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Sample records for cern neutron time

  1. Status and outlook of the neutron time-of-flight facility n_TOF at CERN

    CERN Document Server

    Gunsing, F

    2007-01-01

    The neutron time-of-flight facility n_TOF at CERN, fully operational since 2002, combines a high instantaneous neutron flux with high energy resolution. The wide energy range and the high neutron flux per time-of-flight burst result in a much enhanced signal to background ratio for neutron capture of radioactive isotopes and makes this facility well suited for the measurement of high quality neutron-induced reaction cross-sections. Neutrons are created by spallation reactions induced by a pulsed 20 GeV/c proton beam impinging on a lead target. A 5 cm water slab surrounding the lead target serves as a coolant and at the same time as a moderator of the spallation neutron spectrum, providing a wide energy spectrum from 0.1 eV to about 250 MeV. By the end of 2005, a first phase of data taking has been successfully terminated. Fission and capture experiments have been performed on a variety of isotopes of interest for nuclear astrophysics, advanced nuclear technologies and for basic nuclear physics. The instrument...

  2. Fluence measurement at the neutron time of flight experiment at CERN

    CERN Document Server

    Weiss, Christina; Jericha, Erwin

    At the neutron time of flight facility n_TOF at CERN a new spallation target was installed in 2008. In 2008 and 2009 the commissioning of the new target took place. During the summer 2009 a fission chamber of the Physikalisch Technische Bundesanstalt (PTB) Braunschweig was used for the neutron fluence measurement. The evaluation of the data recorded with this detector is the primary topic of this thesis. Additionally a neutron transmission experiment with air has been performed at the TRIGA Mark II reactor of the Atomic Institute of the Austrian Universities (ATI). The experiment was implemented to clarify a question about the scattering cross section of molecular gas which could not be answered clearly via the literature. This problem came up during the evaluations for n_TOF.

  3. The Proton Beams for the New Time-of-Flight Neutron Facility at the CERN-PS

    CERN Document Server

    Cappi, R; Métral, G

    2000-01-01

    The experimental determination of neutron cross sections in fission and capture reactions as a function of the neutron energy is of primary importance in nuclear physics. Recent developments at CERN and elsewhere have shown that many fields of research and development, such as the design of Accelerator-Driven Systems (ADS) for nuclear waste incineration, nuclear astrophysics, fundamental nuclear physics, dosimetry for radiological protection and therapy, would benefit from a better knowledge of neutron cross sections. A neutron facility at the CERN-PS has been proposed with the aim of carrying out a systematic and high resolution study of neutron cross sections through Time-Of-Flight (n-TOF) measurement. The facility requires a high intensity proton beam (about 0.7x1013 particles/bunch) distributed in a short bunch (about 25 ns total length) to produce the neutrons by means of a spallation process in a lead target. To achieve these characteristics, a number of complex beam gymnastics have to be performed. All...

  4. Neutron beam imaging with micromegas detectors in combination with neutron time-of-flight at the (nTOF) facility at CERN

    International Nuclear Information System (INIS)

    A bulk micromegas detector with the anode segmented in 2 orthogonal directions and equipped with a neutron/charged particle converter is employed at the neutron time-of-flight (nTOF) facility at CERN to determine the incident neutron beam profile and beam interception factor as a function of the neutron energy determined by the time of flight. Discrepancies between experimental results and simulations in the values of the beam interception factor range up to 12 % and are to be ascribed to a defect in the mesh of the bulk. Nevertheless the detector proved to be really useful for checking the alignment of the neutron beam optics of the facility. Measurements with a new pixelized bulk detector for the determination of the beam interception factor are for seen before the end of 2012

  5. The MICROMEGAS neutron detector for CERN n-TOF

    CERN Document Server

    Andriamonje, Samuel A; Giomataris, Ioanis; Jeanneau, F; Pancin, J; Papadopoulos, I M; Vlachoudis, V; Wendler, H; Cano-Ott, D; González, E; Heil, M; Plag, R; Ferrant, L; Ketlerov, V; Karamanis, D; Papaevangelou, T

    2002-01-01

    A novel neutron detector based on the MICROMEGAS concept is presented. One of the applications of this detector is the determination of the high performance and characteristics (neutron beam profile, flux and energy resolution) of the new high-flux spallation neutron source, the neutron Time-Of-Flight facility (n _TOF) at CERN. (11 refs).

  6. Neutron resonance spectroscopy at n-TOF at CERN

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-07-01

    Neutron resonance spectroscopy plays an important role in the investigation of neutron induced reaction cross sections and nuclear structure in the MeV excitation range. Neutron time-of-flight facilities are the most used installations to explore neutron resonances. In this paper we describe the basic features of neutron resonance spectroscopy together with recent results from the time-of-flight facility n-TOF at CERN. (authors)

  7. Neutron resonance spectroscopy at n TOF at CERN

    OpenAIRE

    Calviño Tavares, Francisco; Cortés Rossell, Guillem Pere; Poch Parés, Agustí; Pretel Sánchez, Carme

    2007-01-01

    Neutron resonance spectroscopy plays an important role in the investigation of neutron induced reaction cross sections and nuclear structure in the MeV excitation range. Neutron time-of-flight facilities are the most used installations to explore neutron resonances. In this paper we describe the basic features of neutron resonance spectroscopy together with recent results from the time-of-flight facility n TOF at CERN.

  8. Neutron resonance spectroscopy at n-TOF at CERN

    International Nuclear Information System (INIS)

    Neutron resonance spectroscopy plays an important role in the investigation of neutron induced reaction cross sections and nuclear structure in the MeV excitation range. Neutron time-of-flight facilities are the most used installations to explore neutron resonances. In this paper we describe the basic features of neutron resonance spectroscopy together with recent results from the time-of-flight facility n-TOF at CERN. (authors)

  9. Neutron capture cross section measurement of $^{151}Sm$ at the CERN neutron Time of Flight Facility (nTOF)

    CERN Document Server

    Abbondanno, U; Alvarez-Velarde, F; Alvarez-Pol, H; Andriamonje, Samuel A; Andrzejewski, J; Badurek, G; Baumann, P; Becvar, F; Benlliure, J; Berthoumieux, E; Calviño, F; Cano-Ott, D; Capote, R; Cennini, P; Chepel, V; Chiaveri, Enrico; Colonna, N; Cortés, G; Cortina-Gil, D; Couture, A; Cox, J; Dababneh, S; Dahlfors, M; David, S; Dolfini, R; Domingo-Pardo, C; Durán, I; Embid-Segura, M; Ferrant, L; Ferrari, A; Ferreira-Marques, R; Frais-Kölbl, H; Furman, W; Gonçalves, I; Gallino, R; Gonzalez-Romero, E; Goverdovski, A; Gramegna, F; Griesmayer, E; Gunsing, F; Haas, B; Haight, R; Heil, M; Herrera-Martínez, A; Isaev, S; Jericha, E; Kappeler, F; Kadi, Y; Karadimos, D; Kerveno, M; Ketlerov, V; Köhler, P; Konovalov, V; Krticka, M; Lamboudis, C; Leeb, H; Lindote, A; Lopes, I; Lozano, M; Lukic, S; Marganiec, J; Marrone, S; Martinez-Val, J; Mastinu, P; Mengoni, A; Milazzo, P M; Molina-Coballes, A; Moreau, C; Mosconi, M; Neves, F; Oberhummer, Heinz; O'Brien, S; Pancin, J; Papaevangelou, T; Paradela, C; Pavlik, A; Pavlopoulos, P; Perlado, J M; Perrot, L; Pignatari, M; Plag, R; Plompen, A; Plukis, A; Poch, A; Policarpo, Armando; Pretel, C; Quesada, J; Raman, S; Rapp, W; Rauscher, T; Reifarth, R; Rosetti, M; Rubbia, Carlo; Rudolf, G; Rullhusen, P; Salgado, J; Soares, J C; Stéphan, C; Tagliente, G; Taín, J L; Tassan-Got, L; Tavora, L; Terlizzi, R; Vannini, G; Vaz, P; Ventura, A; Villamarín, D; Vincente, M C; Vlachoudis, V; Voss, F; Wendler, H; Wiescher, M; Wissha, K

    2004-01-01

    The measurement of **1**5**1Sm(n, gamma)**1**5**2Sm (samarium) cross section showed improved performance of the new spallation neutron facility. It covered a wide energy range with good resolution, high neutron flux, low backgrounds and a favourable duty factor. The samarium cross section was found to be of great importance for characterizing neutron capture nucleosynthesis in asymptotic giant stars. The combination of these features provided a promising basis for a broad experimental program directed towards application in astrophysics and advanced nuclear technologies. (Edited abstract)

  10. Optically Stimulated Luminescence Materials for Wide-Spectrum Neutron Measurements at CERN

    CERN Document Server

    Ravotti, F; Idri, K; Vaillé, J R; Prevost, H; Dusseau, L

    2005-01-01

    For the first time, Optically Stimulated Luminescence (OSL) materials with enhanced neutron-sensitivity have been irradiated. The neutron irradiations were carried out in the accelerator-like environment of the IRRAD2 facility at CERN, Geneva, Switzerland and in the TRIGA reactor at JSI, Ljubljana, Slovenia. The results show the possibility to measure with high accuracy the thermal and the fast components of these two different neutron spectra by means of OSL materials doped with Boron or mixed with Polyethylene. The applicability of this technology in the measurement of the neutron components in the complex radiation environment expected at CERN LHC experiments is therefore demonstrated.

  11. Physics at the new CERN neutron beam line

    CERN Document Server

    Guerrero, C

    2014-01-01

    A new neutron beam line (n_TOF EAR - 2) is being built at CERN within the n_TOF facility. Compared to the existing 185 meters long time - of - flight beam line, the new one (which will operate in parallel) will feature a shorter flight of 20 meters, providing a 2 7 times more intense neutron flux extending from thermal to 300 MeV. The scientific program is now bein g discussed and the first detailed proposals will be refereed by February 2014. This contribution is devoted to present and discuss the expected performance of the facility, briefly, and the details of some of the first measureme nts foreseen for 2014 and 2015.

  12. CERN/STANFORD: And now, what makes the neutron spin?

    International Nuclear Information System (INIS)

    Full text: The annual Rencontres de Moriond in the French Alps traditionally provide a clothes line on which to hang interesting new physics results while they are still wet. This year's meeting, from March 20-27, saw exciting news on nucleon spin structure, with the Spin Muon Collaboration (SMC) from CERN and the E142 experiment from Stanford announcing results from data taken in 1992. Both experiments were proposed shortly after the 1987 surprise from the European Muon Collaboration (EMC), when the combination of EMC and earlier Stanford (SLAC) data indicated that little of the proton spin is carried by valence quarks. Spin - the proton's main space-time quantum number - seemed to come mainly from the 'sea' of accompanying quarks and gluons. The SMC and E142 experiments have investigated the spin structure of the neutron, and have tested for the first time the Bjorken sum rule. This is a fundamental prediction of quark-gluon field theory (quantum chromodynamics - QCD) which relates the difference between proton and neutron spin structure to well known coupling constants from neutron beta-decay. At Moriond, SMC showed the spin structure of the deuteron from spinoriented (polarized) muons probing deep inside polarized deuterons, over a wide kinematical range (x, the fraction of the nucleon momentum carried by quarks, running from 0.006 to 0.6). SMC uses the CERN high energy (100-200 GeV) polarized muon beam with a polarized deuteron target made of two separate cells with opposite spin directions. Typical deuteron polarization was about 40%. The spin direction was reversed every eight hours to reduce systematic errors. The SMC result shows that the contribution of quark spins to the deuteron (proton-neutron system) spin is small, and supports the original EMC proton spin findings. Using the proton data, the difference between the spin structures of the proton and the neutron is in good agreement with the prediction of the fundamental Bjorken sum

  13. The CERN n_TOF Facility: Neutron Beams Performances for Cross Section Measurements

    CERN Document Server

    Chiaveri, E; Andrzejewski, J; Audouin, L; Barbagallo, M; Bécares, V; Bečvář, F; Belloni, F; Berthoumieux, E; Billowes, J; Boccone, V; Bosnar, D; Brugger, M; Calviani, M; Calviño, F; Cano-Ott, D; Carrapiço, C; Cerutti, F; Chin, M; Colonna, N; Cortés, G; Cortés-Giraldo, M A; Diakaki, M; Domingo-Pardo, C; Duran, I; Dressler, R; Dzysiuk, N; Eleftheriadis, C; Ferrari, A; Fraval, K; Ganesan, S; García, A R; Giubrone, G; Gómez-Hornillos, M B; Gonçalves, I F; González-Romero, E; Griesmayer, E; Guerrero, C; Gunsing, F; Gurusamy, P; Hernández-Prieto, A; Jenkins, D G; Jericha, E; Kadi, Y; Käppeler, F; Karadimos, D; Kivel, N; Koehler, P; Kokkoris, M; Krtička, M; Kroll, J; Lampoudis, C; Langer, C; Leal-Cidoncha, E; Lederer, C; Leeb, H; Leong, L S; Losito, R; Mallick, A; Manousos, A; Marganiec, J; Martínez, T; Massimi, C; Mastinu, P F; Mastromarco, M; Meaze, M; Mendoza, E; Mengoni, A; Milazzo, P M; Mingrone, F; Mirea, M; Mondalaers, W; Paradela, C; Pavlik, A; Perkowski, J; Plompen, A; Praena, J; Quesada, J M; Rauscher, T; Reifarth, R; Riego, A; Robles, M S; Roman, F; Rubbia, C; Sabaté-Gilarte, M; Sarmento, R; Saxena, A; Schillebeeckx, P; Schmidt, S; Schumann, D; Tagliente, G; Tain, J L; Tarrío, D; Tassan-Got, L; Tsinganis, A; Valenta, S; Vannini, G; Variale, V; Vaz, P; Ventura, A; Versaci, R; Vermeulen, M J; Vlachoudis, V; Vlastou, R; Wallner, A; Ware, T; Weigand, M; Weiss, C; Wright, T; Žugec, P

    2014-01-01

    This paper presents the characteristics of the existing CERN n\\_TOF neutron beam facility (n\\_TOF-EAR1 with a flight path of 185 meters) and the future one (n\\_TOF EAR-2 with a flight path of 19 meters), which will operate in parallel from Summer 2014. The new neutron beam will provide a 25 times higher neutron flux delivered in 10 times shorter neutron pulses, thus offering more powerful capabilities for measuring small mass, low cross section and/or high activity samples.

  14. A Micromegas Detector for Neutron Beam Imaging at the n_TOF Facility at CERN

    CERN Document Server

    Belloni, F; Berthoumieux, E; Calviani, M; Chiaveri, E; Colonna, N; Giomataris, Y; Guerrero, C; Gunsing, F; Iguaz, F J; Kebbiri, M; Pancin, J; Papaevangelou, T; Tsinganis, A; Vlachoudis, V; Altstadt, S; Andrzejewski, J; Audouin, L; Barbagallo, M; Bécares, V; Bečvář, F; Billowes, J; Boccone, V; Bosnar, D; Brugger, M; Calviño, F; Cano-Ott, D; Carrapiço, C; Cerutti, F; Chiaveri, E; Chin, M; Cortés, G; Corté-Giraldo, M A; Diakaki, M; Domingo-Pardo, C; Duran, I; Dzysiuk, N; Eleftheriadis, C; Ferrari, A; Fraval, K; Ganesan, S; García, A R; Giubrone, G; Gómez-Hornillos, M B; Gonçalves, I F; González-Romero, E; Griesmayer, E; Gurusamy, P; Jenkins, D G; Jericha, E; Kadi, Y; Käppeler, F; Karadimos, D; Koehler, P; Kokkoris, M; Krtička, M; Kroll, J; Langer, C; Lederer, C; Leeb, H; Leong, L S; Losito, R; Manousos, A; Marganiec, J; Marítnez, T; Massimi, C; Mastinu, P F; Mastromarco, M; Meaze, M; Mendoza, E; Mengoni, A; Milazzo, P M; Mingrone, F; Mirea, M; Mondalaers, W; Paradela, C; Pavlik, A; Perkowski, J; Plompen, A J M; Praena, J; Quesada, J M; Rauscher, T; Reifarth, R; Riego, A; Roman, F; Rubbia, C; Sarmento, R; Schillebeeckx, P; Schmidt, S; Tagliente, G; Tain, J L; Tarrío, D; Tassan-Got, L; Valenta, S; Vannini, G; Variale, V; Vaz, P; Ventura, A; Versaci, R; Vermeulen, M J; Vlastou, R; Wallner, A; Ware, T; Weigand, M; Weiss, C; Wright, T J; Žugec, P

    2014-01-01

    Micromegas (Micro-MEsh Gaseous Structure) detectors are gas detectors consisting of a stack of one ionization and one proportional chamber. A micromesh separates the two communicating regions, where two different electric fields establish respectively a charge drift and a charge multiplication regime. The n\\_TOF facility at CERN provides a white neutron beam (from thermal up to GeV neutrons) for neutron induced cross section measurements. These measurements need a perfect knowlodge of the incident neutron beam, in particular regarding its spatial profile. A position sensitive micromegas detector equipped with a B-10 based neutron/charged particle converter has been extensively used at the n\\_TOF facility for characterizing the neutron beam profile and extracting the beam interception factor for samples of different size. The boron converter allowed to scan the energy region of interest for neutron induced capture reactions as a function of the neutron energy, determined by the time of flight. Experimental ...

  15. Minimizing the background radiation in the new neutron time-of-flight facility at CERN FLUKA Monte Carlo simulations for the optimization of the n_TOF second experimental line

    CERN Document Server

    Bergström, Ida; Elfgren, Erik

    2013-06-11

    At the particle physics laboratory CERN in Geneva, Switzerland, the Neutron Time-of-Flight facility has recently started the construction of a second experimental line. The new neutron beam line will unavoidably induce radiation in both the experimental area and in nearby accessible areas. Computer simulations for the minimization of the background were carried out using the FLUKA Monte Carlo simulation package. The background radiation in the new experimental area needs to be kept to a minimum during measurements. This was studied with focus on the contributions from backscattering in the beam dump. The beam dump was originally designed for shielding the outside area using a block of iron covered in concrete. However, the backscattering was never studied in detail. In this thesis, the fluences (i.e. the flux integrated over time) of neutrons and photons were studied in the experimental area while the beam dump design was modified. An optimized design was obtained by stopping the fast neutrons in a high Z mat...

  16. Neutron cross-sections for advanced nuclear systems: the n_TOF project at CERN

    Directory of Open Access Journals (Sweden)

    Barbagallo M.

    2014-01-01

    Full Text Available The study of neutron-induced reactions is of high relevance in a wide variety of fields, ranging from stellar nucleosynthesis and fundamental nuclear physics to applications of nuclear technology. In nuclear energy, high accuracy neutron data are needed for the development of Generation IV fast reactors and accelerator driven systems, these last aimed specifically at nuclear waste incineration, as well as for research on innovative fuel cycles. In this context, a high luminosity Neutron Time Of Flight facility, n_TOF, is operating at CERN since more than a decade, with the aim of providing new, high accuracy and high resolution neutron cross-sections. Thanks to the features of the neutron beam, a rich experimental program relevant to nuclear technology has been carried out so far. The program will be further expanded in the near future, thanks in particular to a new high-flux experimental area, now under construction.

  17. Experimental neutron capture data of 58Ni from the CERN n_TOF facility

    Directory of Open Access Journals (Sweden)

    Žugec P.

    2015-01-01

    Full Text Available The neutron capture cross section of 58Ni was measured at the neutron time of flight facility n_TOF at CERN, from 27 meV to 400 keV neutron energy. Special care has been taken to identify all the possible sources of background, with the so-called neutron background obtained for the first time using high-precision GEANT4 simulations. The energy range up to 122 keV was treated as the resolved resonance region, where 51 resonances were identified and analyzed by a multilevel R-matrix code SAMMY. Above 122 keV the code SESH was used in analyzing the unresolved resonance region of the capture yield. Maxwellian averaged cross sections were calculated in the temperature range of kT = 5 – 100 keV, and their astrophysical implications were investigated.

  18. Two exercises about neutrino departure times at CERN

    OpenAIRE

    Berg, Bernd A.; Hoeflich, Peter

    2011-01-01

    Two simple exercises are solved, which educators can use to awake interest of their students in subtleties of the CERN Neutrino beam to Grand Sasso (CNGS) experiment. The first one is about the statistical error of the average departure time of neutrinos from CERN. The second one about a hypothetical bias in the departure times.

  19. Neutron Time-Of-Flight (n_TOF) experiment

    CERN Multimedia

    Brugger, M; Jericha, E; Cortes rossell, G P; Riego perez, A; Baccomi, R; Griesmayer, E; Leeb, H; Dressler, M; Cano ott, D; Variale, V; Ventura, A; Carrillo de albornoz trillo, A; Lo meo, S; Andrzejewski, J J; Pavlik, A F; Kadi, Y; Zanni vlastou, R; Krticka, M; Valenta, S; Weiss, C; Kokkoris, M; Cortes giraldo, M A; Perkowski, J; Losito, R; Audouin, L; Tain enriquez, J L; Tagliente, G; Wallner, A; Woods, P J; Mengoni, A; Guerrero sanchez, C G; Palomo pinto, F R; Vlachoudis, V; Calviani, M; Reifarth, R; Mendoza cembranos, E; Balibrea correra, J; Quesada molina, J M; Praena rodriguez, A J; Schumann, M D; Tsinganis, A; Saxena, A; Rauscher, T; Leal cidoncha, E; Calvino tavares, F; Bondarenko, I; Mingrone, F; Gonzalez romero, E M; Colonna, N; Negret, A L; Chiaveri, E; Milazzo, P M; Ferro pereira goncalves, I M; De almeida carrapico, C A; Castelluccio, D M

    The neutron time-of-flight facility n_TOF at CERN, Switzerland, operational since 2001, delivers neutrons using the Proton Synchrotron (PS) 20 GeV/c proton beam impinging on a lead spallation target. The facility combines a very high instantaneous neutron flux, an excellent time of flight resolution due to the distance between the experimental area and the production target (185 meters), a low intrinsic background and a wide range of neutron energies, from thermal to GeV neutrons. These characteristics provide a unique possibility to perform neutron-induced capture and fission cross-section measurements for applications in nuclear astrophysics and in nuclear reactor technology.

  20. Determination of the Neutron Fluence, the Beam Characteristics and the Backgrounds at the CERN-PS TOF Facility

    CERN Multimedia

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

    2002-01-01

    In the scope of our programme we propose to start in July 2000 with measurements on elements of well known cross sections, in order to check the reliability of the whole experimental installation at the CERN-TOF facility. These initial exploratory measurements will provide the key-parameters required for the further experimentation at the CERN-TOF neutron beam. The neutron fluence and energy resolution will be determined as a function of the neutron kinetic energy by reproducing standard capture and fission cross sections. The measurements of capture cross sections on elements with specific cross section features will allow to us to disentangle the different components of backgrounds and estimate their level in the experimental area. The time-energy calibration will be determined and monitored with a set of monoenergetic filters as well as by the measurements of elements with resonance-dominated cross sections. Finally, in this initial phase the behaviour of several detectors scheduled in successive measureme...

  1. The new vertical neutron beam line at the CERN n-TOF facility design and outlook on the performance

    International Nuclear Information System (INIS)

    At the neutron time-of-flight facility n-TOF at CERN a new vertical beam line was constructed in 2014, in order to extend the experimental possibilities at this facility to an even wider range of challenging cross-section measurements of interest in astrophysics, nuclear technology and medical physics. The design of the beam line and the experimental hall was based on FLUKA Monte Carlo simulations, aiming at maximizing the neutron flux, reducing the beam halo and minimizing the background from neutrons interacting with the collimator or back-scattered in the beam dump. The present paper gives an overview on the design of the beam line and the relevant elements and provides an outlook on the expected performance regarding the neutron beam intensity, shape and energy resolution, as well as the neutron and photon backgrounds

  2. The new vertical neutron beam line at the CERN n-TOF facility design and outlook on the performance

    Energy Technology Data Exchange (ETDEWEB)

    Weiß, C., E-mail: christina.weiss@cern.ch [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Chiaveri, E.; Girod, S.; Vlachoudis, V.; Aberle, O. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Barros, S. [Instituto Tecnológico e Nuclear, Instituto Superior Técnico, Universidade Técnica de Lisboa, Lisboa (Portugal); Bergström, I. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Berthoumieux, E. [Commissariat à l’Énergie Atomique (CEA) Saclay – Irfu, Gif-sur-Yvette (France); Calviani, M. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Guerrero, C.; Sabaté-Gilarte, M. [Universidad de Sevilla (Spain); European Organization for Nuclear Research (CERN), Geneva (Switzerland); Tsinganis, A. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); National Technical University of Athens (NTUA) (Greece); Andrzejewski, J. [Uniwersytet Łódzki, Lodz (Poland); Audouin, L. [Centre National de la Recherche Scientifique/IN2P3 – IPN, Orsay (France); Bacak, M. [Atominstitut, Technische Universität Wien (Austria); Balibrea-Correa, J. [Centro de Investigaciones Energeticas Medioambientales y Tecnológicas (CIEMAT), Madrid (Spain); Barbagallo, M. [Istituto Nazionale di Fisica Nucleare, Bari (Italy); Bécares, V. [Centro de Investigaciones Energeticas Medioambientales y Tecnológicas (CIEMAT), Madrid (Spain); and others

    2015-11-01

    At the neutron time-of-flight facility n-TOF at CERN a new vertical beam line was constructed in 2014, in order to extend the experimental possibilities at this facility to an even wider range of challenging cross-section measurements of interest in astrophysics, nuclear technology and medical physics. The design of the beam line and the experimental hall was based on FLUKA Monte Carlo simulations, aiming at maximizing the neutron flux, reducing the beam halo and minimizing the background from neutrons interacting with the collimator or back-scattered in the beam dump. The present paper gives an overview on the design of the beam line and the relevant elements and provides an outlook on the expected performance regarding the neutron beam intensity, shape and energy resolution, as well as the neutron and photon backgrounds.

  3. Neutron measurements for advanced nuclear systems: The n{sub T}OF project at CERN

    Energy Technology Data Exchange (ETDEWEB)

    Colonna, N., E-mail: nicola.colonna@ba.infn.it [Istituto Nazionale di Fisica Nucleare, Bari (Italy); Andriamonje, S. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Andrzejewski, J. [Uniwersytet Lodzki, Lodz (Poland); Audouin, L. [Centre National de la Recherche Scientifique/IN2P3, IPN, Orsay (France); Barbagallo, M. [Istituto Nazionale di Fisica Nucleare, Bari (Italy); Becares, V. [Centro de Investigaciones Energeticas Medioambientales y Technologicas (CIEMAT), Madrid (Spain); Becvar, F. [Charles University, Prague (Czech Republic); Belloni, F. [Commissariat a l' Energie Atomique (CEA) Saclay - Irfu, Gif-sur-Yvette (France); Berthier, B. [Centre National de la Recherche Scientifique/IN2P3, IPN, Orsay (France); Berthoumieux, E. [Commissariat a l' Energie Atomique (CEA) Saclay - Irfu, Gif-sur-Yvette (France); Brugger, M.; Calviani, M. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Calvino, F. [Universitat Politecnica de Catalunya, Barcelona (Spain); Cano-Ott, D. [Centro de Investigaciones Energeticas Medioambientales y Technologicas (CIEMAT), Madrid (Spain); Carrapico, C. [Instituto Tecnologico e Nuclear (ITN), Lisbon (Portugal); Cennini, P.; Cerutti, F.; Chiaveri, E.; Chin, M. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Cortes, G. [Universitat Politecnica de Catalunya, Barcelona (Spain); and others

    2011-12-15

    A few years ago, the neutron time-of-flight facility n{sub T}OF was built at CERN to address some of the urgent needs of high-accuracy nuclear data for Accelerator Driven Systems and other advanced nuclear energy systems, as well as for nuclear astrophysics and fundamental nuclear physics. Thanks to the characteristics of the neutron beam, and to state-of-the-art detection and acquisition systems, high quality neutron cross-section data have been obtained for a variety of isotopes, many of which radioactive. Following an important upgrade of the spallation target and of the experimental area, a new measurement campaign has started last year. After a brief review of the most important results obtained so far at n{sub T}OF, the new features of the facility are presented, together with the first results on the commissioning of the neutron beam. The plans for future measurements, in particular related to nuclear technology are finally discussed.

  4. Cern

    CERN Multimedia

    2009-01-01

    "La réparation de l'accélérateur géant de particules LHC, qui devrait redémarrer mi-novembre aprés une panne de plus d'un an, a coûté 23 millions d'euros, selon un haut responsable du Centre européen de recherche nucléaire (CERN), cité vendredi par les médias espagnols" (1 paragraph)

  5. Measurement of the neutron capture cross section of 234U in n-TOF at CERN

    International Nuclear Information System (INIS)

    Accurate and reliable neutron capture cross sections are needed in many research areas, including stellar nucleosynthesis, advanced nuclear fuel cycles, waste transmutation, and other applied programs. In particular, the accurate knowledge of 234U(n, γ) reaction cross section is required for the design and realization of nuclear power stations based on the thorium fuel cycle. We have measured the neutron capture cross section of 234U at the recently constructed neutron time-of-flight facility n-TOF at CERN [2] in the energy range from 0.03 eV to 1 MeV with high accuracy due to a combination of features unique in the world: A high instantaneous neutron fluence and excellent energy resolution of the n-TOF facility, an innovative Data Acquisition System based on flash ADCs [3] and the use of a high performance 4Π BaF2 Total Absorption Calorimeter (TAC) as a detection device [4, 5], In this paper, we will describe the experimental apparatus including the various TAC components and its performance. We also will present results from the 234U(n, γ) measurement. A sample of 38.7 mg of 234U3O8 was pressed into a pellet and doubly encapsulated between Al and Ti foils which were 0.15 mm and 0.2 mm thick, respectively. Monte-Carlo simulations with GEANT4 [6] of the detector response have been performed. After the background subtraction and correction with dead time and pile-up, the capture yield from 0.03 eV up to 1.5 keV was derived. Preliminary analysis of the capture yield in terms of R-matrix resonance parameters is discussed. (authors)

  6. Neutron cross-sections for advanced nuclear systems. The nTOF project at CERN

    International Nuclear Information System (INIS)

    In 2012, nuclear energy continued to play an important role in global electricity production. Despite a small reduction of the total generating nuclear power capacity after the accident at the Fukushima Daiichi nuclear power plant, a significant growth, between 35% and 100% by 2030, is foreseen in the use of nuclear energy worldwide. The knowledge of a wide variety of nuclear processes is a fundamental prerequisite in nuclear technology, as well as in other field of fundamental and applied Nuclear Physics. In particular, neutron-induced reactions play a key role in the operation of present nuclear reactors as well as in the design of future ones aiming at minimizing nuclear waste, such as Generation-IV reactors, ADS or reactors based on Th/U fuel cycle. The cross sections of a large number of neutron-induced reactions are requested with high accuracy to improve safety and efficiency of current reactors, and for the design of future generation systems. Since 2001 nTOF, an innovative neutron Time-Of-Flight facility, has been operating at CERN with the aim of addressing the needs of nuclear data for basic and applied nuclear Physics. An extensive program on both neutron induced fission and capture reactions has been carried out so far. Thanks to the well suited features of the nTOF neutron beam, such as the high instantaneous neutron flux, the high resolution and the wide energy range covered, from thermal to a few GeV, coupled with state-of-the-art detectors and data acquisition system, it has been possible to collect high accuracy and high resolution neutron cross-section data on a variety of isotopes, many of which radioactive. In particular, important results for nuclear technologies have been obtained on isotopes of U, Pu and minor actinides with long half life. Recently the construction of a new, high-flux measuring station has started. A 25 times higher fluence relative to the existing experimental area will allow to measure isotopes with short half life, as

  7. Summer at CERN: a time to make friends

    CERN Multimedia

    2013-01-01

    Summer brings the opportunity for many of us to spend time enjoying the company of our families and friends. It also brings a new generation of young people to CERN – the summer students.   We often talk about the extended CERN community as a being like a big family, where the common bond is the science we do. The summer students who join us every year are in many ways the newest additions to this family. This year we have welcomed 276 students in total, with an impressive 133 from non-Member states. As usual they are joining in the learning experience that the programme offers and taking the opportunity to socialise. However, this year they are showing a particular enthusiasm for developing activities together that are linked to spreading the message about CERN. They’ve shown great support for the CERN Summer Student Webfest – now in its second year - where they were invited to work in teams and design web apps that will encourage the public to learn more abou...

  8. Study of muon-induced neutron production using accelerator muon beam at CERN

    International Nuclear Information System (INIS)

    Cosmogenic muon-induced neutrons are one of the most problematic backgrounds for various underground experiments for rare event searches. In order to accurately understand such backgrounds, experimental data with high-statistics and well-controlled systematics is essential. We performed a test experiment to measure muon-induced neutron production yield and energy spectrum using a high-energy accelerator muon beam at CERN. We successfully observed neutrons from 160 GeV/c muon interaction on lead, and measured kinetic energy distributions for various production angles. Works towards evaluation of absolute neutron production yield is underway. This work also demonstrates that the setup is feasible for a future large-scale experiment for more comprehensive study of muon-induced neutron production

  9. Experimental tests of an advanced proton-to-neutron converter at ISOLDE-CERN

    CERN Document Server

    Gottberg, A; Luis, R; Ramos, J P; Seiffert, C; Cimmino, S; Marzari, S; Crepieux, B; Manea, V; Wolf, R N; Wienholtz, F; Kreim, S; Fedosseev, V N; Marsh, B A; Rothe, S; Vaz, P; Marques, J G; Stora, T

    2014-01-01

    The suppression of isobaric contaminations is of growing importance for many scientific programs using radioactive isotopes produced at isotope separation on-line (ISOL) facilities, such as ISOLDE-CERN. A solid tungsten proton-to-neutron converter has been used for ten years to produce neutron-rich fission fragments from an UC x target while suppressing the production of neutron-deficient isobaric contaminants. The remaining contamination is mainly produced by primary protons that are scattered by the heavy neutron converter and finally impinge on the UC x target itself. Therefore, the knowledge of the energy-dependant cross-sections of proton and neutron induced fission events is crucial in order to evaluate future converter concepts.

  10. Measurements of neutron cross sections for advanced nuclear energy systems at n_TOF (CERN

    Directory of Open Access Journals (Sweden)

    Barbagallo M.

    2014-03-01

    Full Text Available The n_TOF facility operates at CERN with the aim of addressing the request of high accuracy nuclear data for advanced nuclear energy systems as well as for nuclear astrophysics. Thanks to the features of the neutron beam, important results have been obtained on neutron induced fission and capture cross sections of U, Pu and minor actinides. Recently the construction of another beam line has started; the new line will be complementary to the first one, allowing to further extend the experimental program foreseen for next measurement campaigns.

  11. Instrument intercomparison in the pulsed neutron fieldsat the CERN HiRadMat facility

    CERN Document Server

    Aza, E; Cassell, C; Charitonidis, N; Harrouch, E; Manessi, G P; Pangallo, M; Perrin, D; Samara, E; Silari, M

    2014-01-01

    An intercomparison of the performances of active neutron detectors was carried out in pulsed neutron fi elds in the new HiRadMat facility at CERN. Five detectors were employed: four of them (two ionization chambers and two rem counters) are routinely employed in the CERN radiation monitoring system, while the fi fth is a novel instrument, called LUPIN, speci fi cally conceived for applications in pulsed neutron fi elds. The measurements were performed in the stray fi eld generated by a proton beam of very short duration with momentum of 440 GeV/c impinging on a dump. The beam intensity was steadily increased during the experiment by more than three orders of magnitude, with an H*(10) due to neutrons at the detector reference positions varying between a few nSv per burst and a few m Sv per burst, whereas the gamma contribution to the total H*(10) was negligible. The aim of the experiment was to evaluate the linearity of the detector response in extreme pulsed conditions as a function of the neutron burst in- t...

  12. Simultaneous measurement of neutron-induced capture and fission reactions at CERN

    Energy Technology Data Exchange (ETDEWEB)

    Guerrero, C. [European Organization for Nuclear Research, Geneva (Switzerland); Centro de Investigaciones Energeticas Medioambientales y Technologicas (CIEMAT), Madrid (Spain); Berthoumieux, E. [European Organization for Nuclear Research, Geneva (Switzerland); Commissariat a l' Energie Atomique Saclay - Irfu, Gif-sur-Yvette (France); Cano-Ott, D.; Mendoza, E.; Becares, V.; Fernandez-Ordonez, M.; Gonzalez-Romero, E.; Marganiec, J.; Martinez, T. [Centro de Investigaciones Energeticas Medioambientales y Technologicas, Madrid (Spain); Andriamonje, S.; Brugger, M.; Calviani, M.; Cerutti, F.; Chiaveri, E.; Chin, M.; Ferrari, A.; Kadi, Y.; Lebbos, E.; Losito, R.; Rubbia, C.; Vlachoudis, V. [European Organization for Nuclear Research, Geneva (Switzerland); Andrzejewski, J.; Perkowski, J. [Uniwersytet Lodzki, Lodz (Poland); Audouin, L.; Tassan-Got, L. [Centre National de la Recherche Scientifique/IN2P3 - IPN, Orsay (France); Barbagallo, M.; Colonna, N.; Marrone, S.; Meaze, M.; Tagliente, G.; Variale, V. [Istituto Nazionale di Fisica Nucleare, Bari (Italy); Becvar, F.; Kroll, J.; Krticka, M. [Charles Univ., Prague (Czech Republic); Belloni, F.; Milazzo, P.M. [Istituto Nazionale di Fisica Nucleare, Trieste (Italy); Billowes, J.; Ware, T.; Wright, T. [Univ. of Manchester, Manchester (United Kingdom); Calvino, F.; Cortes, G.; Gomez-Hornillos, M.B. [Univ. Politecnica de Catalunya, Barcelona (Spain); Carrapico, C.; Goncalves, I.F.; Sarmento, R.; Vaz, P. [Instituto Tecnologico e Nuclear, Lisbon (Portugal); Cortes-Giraldo, M.A.; Lozano, M.; Praena, J.; Quesada, J.M. [Univ. de Sevilla, Sevilla (Spain); Diakaki, M.; Karadimos, D.; Vlastou, R. [National Technical Univ. of Athens, Athens (Greece); Dillmann, I. [Technische Univ. Muenchen, Physik Dept. E12 and Excellence Cluster Universe, Munich (Germany); Domingo-Pardo, C.; Plag, R.; Reifarth, R. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany)] [and others

    2012-03-15

    The measurement of the capture cross-section of fissile elements, of utmost importance for the design of innovative nuclear reactors and the management of nuclear waste, faces particular difficulties related to the {gamma} -ray background generated in the competing fission reactions. At the CERN neutron time-of-flight facility n{sub T}OF we have combined the Total Absorption Calorimeter (TAC) capture detector with a set of three {sup 235}U loaded MicroMegas (MGAS) fission detectors for measuring simultaneously two reactions: capture and fission. The results presented here include the determination of the three detection efficiencies involved in the process: {epsilon}{sub TAC}(n,f), {epsilon}{sub TAC}(n,{gamma}) and {epsilon}{sub MGAS}(n,f). In the test measurement we have succeeded in measuring simultaneously with a high total efficiency the {sup 235}U capture and fission cross-sections, disentangling accurately the two types of reactions. The work presented here proves that accurate capture cross-section measurements of fissile isotopes are feasible at n{sub T}OF. (orig.)

  13. Experimental tests of an advanced proton-to-neutron converter at ISOLDE-CERN

    Energy Technology Data Exchange (ETDEWEB)

    Gottberg, A. [European Organization for Nuclear Research – CERN 1211, Geneva 23 (Switzerland); Consejo Nacional de Pesquisas Cientificas CSIC, Instituto de Estructura de la Materia, 28006 Madrid (Spain); Mendonca, T.M. [European Organization for Nuclear Research – CERN 1211, Geneva 23 (Switzerland); IFIMUP and IN – Institut of Nanosciences and Nanotechnologies, Rua do Campo Alegre 687, 4169-007 Porto (Portugal); Luis, R. [Instituto Superior Técnico, Campus Tecnológico e Nuclear – IST-CTN, Estrada Nacional 10 (km 139, 7), 2695-066 Bobadela LRS (Portugal); Ramos, J.P. [European Organization for Nuclear Research – CERN 1211, Geneva 23 (Switzerland); École Polytechnique Fédérale de Lausanne – EPFL, 1015 Lausanne (Switzerland); Seiffert, C. [European Organization for Nuclear Research – CERN 1211, Geneva 23 (Switzerland); Technische Universität Darmstadt, 64289 Darmstadt (Germany); Cimmino, S.; Marzari, S.; Crepieux, B. [European Organization for Nuclear Research – CERN 1211, Geneva 23 (Switzerland); Manea, V. [CSNSM-IN2P3-CNRS, Université Paris-Sud, 91405 Orsay (France); Wolf, R.N.; Wienholtz, F. [Institut für Physik, Ernst-Moritz-Arndt Universität Greifswald, 17487 Greifswald (Germany); Kreim, S. [European Organization for Nuclear Research – CERN 1211, Geneva 23 (Switzerland); Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany); Fedosseev, V.N.; Marsh, B.A.; Rothe, S. [European Organization for Nuclear Research – CERN 1211, Geneva 23 (Switzerland); and others

    2014-10-01

    The suppression of isobaric contaminations is of growing importance for many scientific programs using radioactive isotopes produced at isotope separation on-line (ISOL) facilities, such as ISOLDE-CERN. A solid tungsten proton-to-neutron converter has been used for ten years to produce neutron-rich fission fragments from an UC{sub x} target while suppressing the production of neutron-deficient isobaric contaminants. The remaining contamination is mainly produced by primary protons that are scattered by the heavy neutron converter and finally impinge on the UC{sub x} target itself. Therefore, the knowledge of the energy-dependant cross-sections of proton and neutron induced fission events is crucial in order to evaluate future converter concepts. In this paper, an improved neutron converter prototype design is presented together with the experimentally assessed radioisotope production of Rb, Zn, Cu, Ga and In that validate the converter concept aiming at beams of higher purity neutron-rich isotopes. The experimentally derived release efficiencies for isotopes produced by the 1.4 GeV protons available at ISOLDE are used to evaluate the Monte Carlo code FLUKA and the cross-section codes TALYS and ABRABLA, respectively.

  14. Experimental tests of an advanced proton-to-neutron converter at ISOLDE-CERN

    International Nuclear Information System (INIS)

    The suppression of isobaric contaminations is of growing importance for many scientific programs using radioactive isotopes produced at isotope separation on-line (ISOL) facilities, such as ISOLDE-CERN. A solid tungsten proton-to-neutron converter has been used for ten years to produce neutron-rich fission fragments from an UCx target while suppressing the production of neutron-deficient isobaric contaminants. The remaining contamination is mainly produced by primary protons that are scattered by the heavy neutron converter and finally impinge on the UCx target itself. Therefore, the knowledge of the energy-dependant cross-sections of proton and neutron induced fission events is crucial in order to evaluate future converter concepts. In this paper, an improved neutron converter prototype design is presented together with the experimentally assessed radioisotope production of Rb, Zn, Cu, Ga and In that validate the converter concept aiming at beams of higher purity neutron-rich isotopes. The experimentally derived release efficiencies for isotopes produced by the 1.4 GeV protons available at ISOLDE are used to evaluate the Monte Carlo code FLUKA and the cross-section codes TALYS and ABRABLA, respectively

  15. On the figure of merit in neutron time-of-flight measurements

    CERN Document Server

    Mengoni, Alberto; Frisoni, M; Magnani, M

    2002-01-01

    We address the task of evaluating the basic performances of neutron time-of-flight spectrometers, by means of an appropriate figure of merit. Calculations of neutron flux, energy resolution, and figure of merit are presented with a critical discussion on their definitions. The results of Monte Carlo simulations for two presently operating facilities, CERN n_TOF and GELINA, are commented and compared.

  16. The transmission of accelerator timing information around CERN

    International Nuclear Information System (INIS)

    Prior to the construction of the Large Electron Positron (LEP) collider, machine timing information was transmitted around CERN's accelerators using a labyrinth of dedicated copper wires. However, at an early stage in the design of the LEP control system, it was decided to use an integrated communication system based on Time Division Multiplex (TDM) techniques. Therefore it was considered appropriate to use this facility to transmit timing information over long distances. This note describes the overall system, with emphasis placed on the connectivity requirements for the CCITT G.703 series of recommendations. In addition the methods used for error detection and correction, and also for redundancy, are described. The cost implications of using such a TDM based system are also analyzed. Finally the performance and reliability obtained by using this approach are discussed. (author)

  17. Neutron cross-section for P and T and Ads at the N-TOF facility at CERN

    International Nuclear Information System (INIS)

    An innovative neutron time of flight facility (n-TOF) has recently become operative at CERN. Neutrons in a wide energy range (1 eVn<250 MeV) are generated by spallation of 20 GeV/c protons on a lead target. The instantaneously very intense neutron flux, low duty cycle, high resolution and low background make this facility unique for cross-section measurements relevant to Nuclear Astrophysics, fundamental Nuclear Physics, and particularly for Nuclear Technology, where most of the isotopes of interest are highly radioactive and available only in small samples. The n-TOF collaboration has proposed a vast experimental programme on capture, fission and (n,xn) reaction. The main objective is the study of isotopes and reactions relevant to Accelerator-driven Systems (ADS) for nuclear waste transmutation and nuclear energy production. Studies of capture reactions relevant to Nuclear Astrophysics will also benefit from the innovative characteristics of the n-TOF neutron beam. This paper presents the present status and the first raw results. This work is supported by the European Commission under the contract n. FIKW-CT-2000- 00107. (author)

  18. CERN physicists want more time to look for Higgs boson

    CERN Multimedia

    2000-01-01

    A new event has increased the probability that CERN scientists have really seen the Higgs boson. It has led to demands that the closure of LEP be further postponed, perhaps for up to a year (2 paragraphs).

  19. Time-resolved neutron imaging at ANTARES cold neutron beamline

    OpenAIRE

    Tremsin, A.S.; Dangendorf, V.; Tittelmeier, K.; Schillinger, B.; Schulz, M.; Lerche, M.; Feller, W. B.

    2015-01-01

    In non-destructive evaluation with X-rays light elements embedded in dense, heavy (or high-Z) matrices show little contrast and their structural details can hardly be revealed. Neutron radiography, on the other hand, provides a solution for those cases, in particular for hydrogenous materials, owing to the large neutron scattering cross section of hydrogen and uncorrelated dependency of neutron cross section on the atomic number. The majority of neutron imaging experiments at the present time...

  20. Neutron time-of-flight diffractometry

    International Nuclear Information System (INIS)

    Specific possibilities of neutron time-of-flight diffractometry for structural studies are considered. Special attention is paid to correlation neutron diffractometry, kinetic processes, applications of external electric and magnetic fields and high pressures. 133 refs., 20 figs., 5 tabs

  1. Neutron emission time measurements for ICF targets

    International Nuclear Information System (INIS)

    The neutron emission time for laser-driven inertial confinement fusion targets is determined from data recorded with fast neutron and optical detector systems. Two types of neutron detectors are used. Radiation-induced conductivity devices have a 130-ps FWHM response and are sensitive to targets with yields greater than 5 x 10/sup 10/ DT neutrons. They measure the average neutron emission time with a precision of +- 50 ps and are fast enough to measure the neutron production rate within a target core as a function of time. Plastic scintillators coupled to microchannel-plate photomultiplier tubes have a 1.2-ns FWHM response and measure the average neutron emission time with a precision of +- 75 ps for targets with yields greater than 106 neutrons. Streak cameras record the incident laser power. Optical fiducial signals that are injected into each detector are used to cross time between the detector systems. Measurements made on 1-mm-diam spherical targets irradiated with 23 kJ of 0.35-μm light delivered in a temporally square 1.1-ns pulse and yielding 10/sup 13/ neutrons show a burn duration greater than 300 ps and an average neutron emission time of about 850 ps

  2. Time-resolved neutron imaging at ANTARES cold neutron beamline

    CERN Document Server

    Tremsin, A S; Tittelmeier, K; Schillinger, B; Schulz, M; Lerche, M; Feller, W B

    2015-01-01

    In non-destructive evaluation with X-rays light elements embedded in dense, heavy (or high-Z) matrices show little contrast and their structural details can hardly be revealed. Neutron radiography, on the other hand, provides a solution for those cases, in particular for hydrogenous materials, owing to the large neutron scattering cross section of hydrogen and uncorrelated dependency of neutron cross section on the atomic number. The majority of neutron imaging experiments at the present time is conducted with static objects mainly due to the limited flux intensity of neutron beamline facilities and sometimes due to the limitations of the detectors. However, some applications require the studies of dynamic phenomena and can now be conducted at several high intensity beamlines such as the recently rebuilt ANTARES beam line at the FRM-II reactor. In this paper we demonstrate the capabilities of time resolved imaging for repetitive processes, where different phases of the process can be imaged simultaneously and...

  3. Time-energy relation of the nTOF neutron beam: energy standards revisited

    International Nuclear Information System (INIS)

    The accurate determination of neutron cross-sections as a function of the neutron energy at a time-of-flight facility requires a precise knowledge of the time-energy relation for the neutron beam. For the nTOF neutron beam at CERN, produced by spallation of high-energy protons on a Pb target, the time-energy relation is connected to the production mechanism and to the subsequent moderation process. A calibration of the neutron energy scale is proposed based on detailed Monte Carlo simulations of the facility. This time-energy relation has been experimentally validated by means of dedicated measurements of standard energy resonances, from 1 eV to approximately 1 MeV. On the basis of the present measurements, it is proposed to correct the energy of the 1.3 eV resonance of 193Ir, which is commonly considered as an energy standard

  4. The n{sub T}OF Total Absorption Calorimeter for neutron capture measurements at CERN

    Energy Technology Data Exchange (ETDEWEB)

    Guerrero, C. [Centro de Investigaciones Energeticas Medioambientales y Tecnologicas, Madrid (Spain)], E-mail: carlos.guerrero@ciemat.es; Abbondanno, U. [Istituto Nazionale di Fisica Nucleare, Trieste (Italy); Aerts, G. [CEA/Saclay - DSM/DAPNIA, Gif-sur-Yvette (France); Alvarez, H. [Universidade de Santiago de Compostela (Spain); Alvarez-Velarde, F. [Centro de Investigaciones Energeticas Medioambientales y Tecnologicas, Madrid (Spain); Andriamonje, S. [CEA/Saclay - DSM/DAPNIA, Gif-sur-Yvette (France); Andrzejewski, J. [University of Lodz, Lodz (Poland); Assimakopoulos, P. [University of Ioannina (Greece); Audouin, L. [Centre National de la Recherche Scientifique/IN2P3-IReS, Strasbourg (France); Badurek, G. [Atominstitut der Osterreichischen Universitaeten, Technische Universitaet Wien (Austria); Baumann, P. [Centre National de la Recherche Scientifique/IN2P3-IReS, Strasbourg (France); Becvar, F. [Charles University, Prague (Czech Republic); Berthoumieux, E. [CEA/Saclay - DSM/DAPNIA, Gif-sur-Yvette (France); Calvino, F. [Universidad Politecnica de Catalunya (Spain); Calviani, M. [Istituto Nazionale di Fisica Nucleare (INFN), Laboratori Nazionali di Legnaro (Italy); Cano-Ott, D. [Centro de Investigaciones Energeticas Medioambientales y Tecnologicas, Madrid (Spain); Capote, R. [International Atomic Energy Agency (IAEA), Nuclear Data Section, Vienna (Austria); Universidad de Sevilla (Spain); Carrapico, C. [CEA/Saclay - DSM/DAPNIA, Gif-sur-Yvette (France); Instituto Tecnologico e Nuclear(ITN), Lisbon (Portugal); Cennini, P. [CERN, Geneva (Switzerland); Chepel, V. [LIP - Coimbra and Departamento de Fisica da Universidade de Coimbra (Portugal)] (and others)

    2009-09-21

    The n{sub T}OF Collaboration has built and commissioned a high-performance detector for (n,{gamma}) measurements called the Total Absorption Calorimeter (TAC). The TAC was especially designed for measuring neutron capture cross-sections of low-mass and/or radioactive samples with the accuracy required for nuclear technology and stellar nucleosynthesis. We present a detailed description of the TAC and discuss its overall performance in terms of energy and time resolution, background discrimination, detection efficiency and neutron sensitivity.

  5. Time-resolved neutron imaging at ANTARES cold neutron beamline

    Science.gov (United States)

    Tremsin, A. S.; Dangendorf, V.; Tittelmeier, K.; Schillinger, B.; Schulz, M.; Lerche, M.; Feller, W. B.

    2015-07-01

    In non-destructive evaluation with X-rays light elements embedded in dense, heavy (or high-Z) matrices show little contrast and their structural details can hardly be revealed. Neutron radiography, on the other hand, provides a solution for those cases, in particular for hydrogenous materials, owing to the large neutron scattering cross section of hydrogen and uncorrelated dependency of neutron cross section on the atomic number. The majority of neutron imaging experiments at the present time is conducted with static objects mainly due to the limited flux intensity of neutron beamline facilities and sometimes due to the limitations of the detectors. However, some applications require the studies of dynamic phenomena and can now be conducted at several high intensity beamlines such as the recently rebuilt ANTARES beam line at the FRM-II reactor. In this paper we demonstrate the capabilities of time resolved imaging for repetitive processes, where different phases of the process can be imaged simultaneously and integrated over multiple cycles. A fast MCP/Timepix neutron counting detector was used to image the water distribution within a model steam engine operating at 10 Hz frequency. Within neutron radiography for the future applications. The neutron spectrum of the ANTARES beamline as well as transmission spectra of a Fe sample were also measured with the Time Of Flight (TOF) technique in combination with a high resolution beam chopper. The energy resolution of our setup was found to be ~ 0.8% at 5 meV and ~ 1.7% at 25 meV. The background level (most likely gammas and epithermal/fast neutrons) of the ANTARES beamline was also measured in our experiments and found to be on the scale of 3% when no filters are installed in the beam. Online supplementary data available from stacks.iop.org/jinst/10/P07008/mmedia. The videos are given as supplementary material linked to the main article.

  6. The CERN Canoe and Kayak Club has a swimming time

    CERN Multimedia

    2008-01-01

    The new Canoe and Kayak Club, which was formed at the start of the 2006 winter season, already has around twenty members, including some former top-level sportsmen. Catharine Noble, of the IT Department was ranked 13th overall in women’s British freestyle in 1997. Here she is performing a flat loop, a position that can be held for several seconds.Would you be interested in a spot of lunchtime canoeing or kayaking to break up a long working day? Or are you more of an evening sports enthusiast? The CERN Canoe and Kayak Club offers both options, as well as a choice of flat-water and white-water activities to suit all temperaments. With its calm waters and easy access for boats, the Peney nature reserve is ideal for beginners. Outings comprise a few exercises to acquire the techniques, as well as games to make the learning experience more fun and spontaneous. These waters are not only frequented by beginners, however, but also by thos...

  7. Fission-neutrons source with fast neutron-emission timing

    Science.gov (United States)

    Rusev, G.; Baramsai, B.; Bond, E. M.; Jandel, M.

    2016-05-01

    A neutron source with fast timing has been built to help with detector-response measurements. The source is based on the neutron emission from the spontaneous fission of 252Cf. The time is provided by registering the fission fragments in a layer of a thin scintillation film with a signal rise time of 1 ns. The scintillation light output is measured by two silicon photomultipliers with rise time of 0.5 ns. Overall time resolution of the source is 0.3 ns. Design of the source and test measurements using it are described. An example application of the source for determining the neutron/gamma pulse-shape discrimination by a stilbene crystal is given.

  8. Neutron-computer tomography using real-time neutron radiography

    International Nuclear Information System (INIS)

    A real-time neutron radiography facility was constructed including the capability of neutron tomography. The neutron beam was measured for total neutron flux ((1.0 +/- 0.2) x 1011 m/(m2-sec)), gold cadmium ratio (52 +/- 3) and effective neutron temperature (830C +/- 80C). The angular divergence or nonparallelism of the neutron beam was measured to be 2.30 +/- 0.10 thereby providing a means of quantifying the collimator effectiveness. The resolution capabilities of both static film and real-time neutron radiographs were quantified using a Fourier transform algorithm to calculate the modulation transfer function of both types of radiographs. The contrast sensitivity of both types of radiographs. The contrast sensitivity of both types of radiographs was measured as 3.1% for film and 4.0% for real-time radiographs. Two tomography algorithms, the simultaneous iterative reconstruction technique (SIRT) and the convolution method, were programmed on an Intellect 100 Image Processing System. The SIRT algorithm was found to be too large and slow on the Intellect 100 to produce useful tomographs. The convolution method produced results near the theoretical resolution limits for a given number of projections. A tomographic resolution of at least 1.3 mm was demonstrated using 200 projections. Computer running time for the convolution method was found to be ∼ 30 seconds for each projection used. A series of experiments were conducted using the convolution method investigating the effect of high and low pass filtering, diagonal line enhancement and contrast stretching on the finished tomographs. These experiments showed that spatial resolution is not generally improved by these filtering functions but contrast sensitivity of the tomographs is improved

  9. Time of flight fast neutron radiography

    International Nuclear Information System (INIS)

    Neutron radiography with fast or thermal neutrons is a standard technique for non-destructive testing (NDT). Here we report results for fast neutron radiography both as an adjunct to pulsed fast neutron analysis (PFNA) and as a stand-alone method for NDT. PFNA is a new technique for utilizing a collimated pulsed neutron beam to interrogate items and determine their elemental composition. By determining the time of flight for gamma-rays produced by (n,n' gamma X) reactions, a three dimensional image can be produced. Neutron radiography data taken with the same beam provides an important constraint for image reconstruction, and in particular is important in inferring the amount of hydrogen within the interrogated item. As a stand-alone device, the radiography measurement can be used to image items as large as cargo containers as long as their density is not too high. The use of a pulsed beam gives the further advantage of a time of flight measurement on the transmitted neutrons. By gating the radiography signal on the time of flight appropriate to the energy of the primary neutrons, most build-up from scattered neutrons can be eliminated. The pulsed beam also greatly improves the signal to background and extends the range of the neutron radiography. Simulation results will be presented which display the advantage of this constraint in particular for statistically limited data. Experimental results will be presented which show some of the limitations likely in a PFNA system utilizing neutron radiography data. Experimental and simulation results will demonstrate possible uses for this type of radiographic data in identifying contraband substances such as drugs. (orig.)

  10. Time-resolved neutron imaging at ANTARES cold neutron beamline

    International Nuclear Information System (INIS)

    In non-destructive evaluation with X-rays light elements embedded in dense, heavy (or high-Z) matrices show little contrast and their structural details can hardly be revealed. Neutron radiography, on the other hand, provides a solution for those cases, in particular for hydrogenous materials, owing to the large neutron scattering cross section of hydrogen and uncorrelated dependency of neutron cross section on the atomic number. The majority of neutron imaging experiments at the present time is conducted with static objects mainly due to the limited flux intensity of neutron beamline facilities and sometimes due to the limitations of the detectors. However, some applications require the studies of dynamic phenomena and can now be conducted at several high intensity beamlines such as the recently rebuilt ANTARES beam line at the FRM-II reactor. In this paper we demonstrate the capabilities of time resolved imaging for repetitive processes, where different phases of the process can be imaged simultaneously and integrated over multiple cycles. A fast MCP/Timepix neutron counting detector was used to image the water distribution within a model steam engine operating at 10 Hz frequency. Within <10 minutes integration the amount of water was measured as a function of cycle time with a sub-mm spatial resolution, thereby demonstrating the capabilities of time-resolved neutron radiography for the future applications. The neutron spectrum of the ANTARES beamline as well as transmission spectra of a Fe sample were also measured with the Time Of Flight (TOF) technique in combination with a high resolution beam chopper. The energy resolution of our setup was found to be ∼ 0.8% at 5 meV and ∼ 1.7% at 25 meV. The background level (most likely gammas and epithermal/fast neutrons) of the ANTARES beamline was also measured in our experiments and found to be on the scale of 3% when no filters are installed in the beam. Online supplementary data available from stacks

  11. Neutron-induced fission cross section measurement of 233U, 241Am and 243Am in the energy range 0.5 MeV En 20 MeV at nTOF at CERN

    Energy Technology Data Exchange (ETDEWEB)

    Belloni, F. [Instituto Nazionale de Fisica Nucleare-Italy and CEA-France; Milazzo, P. M. [Instituto Nazionale de Fisica Nucleare, Trieste, Italy; Calviani, M. [Laboratori Nazionali di Legnaro, Italy and CERN, Geneva, Switzerland; Colonna, N. [Instituto Nazionale di Fisica Nucleare, Bari, Italy; Mastinu, P. F. [INFN, Laboratori Nazionali di Legnaro, Italy; Abbondanno, U. [Instituto Nazionale de Fisica Nucleare, Trieste, Italy; Aerts, G. [French Atomic Energy Commission (CEA), Centre de Saclay, Gif sur Yvette; Alvarez, H. [University of Santiago de Compostela, Spain; Alvarez-Velarde, F. [Centro de Investigaciones Energeticas Medioambientales y Technol., Madrid, Spain; Andriamonje, S. [French Atomic Energy Commission (CEA), Centre de Saclay, Gif sur Yvette; Andrzejewski, J. [University of Lodz, Lodz, Poland; Assimakopoulos, P. A. [University of Ioannina, Greece; Audouin, L. [Centre National de la Recherche Scidntifique/IN2P3-IPN, Orsay, France; Badurek, G. [Vienna University of Technology, Austria; Barbagallo, M. [Instituto Nazionale di Fisica Nucleare, Bari, Italy; Baumann, P. [CNRS, Strasbourg, France; Becvar, F. [Charles University, Prague, Czech Republic; Berthoumieux, E. [French Atomic Energy Commission (CEA), Centre de Saclay, Gif sur Yvette; Calvino, F. [Universidad Politecnica de Madrid, Spain; Cerutti, F. [CERN, Geneva, Switzerland; Cano-Ott, D. [CIEMAT, Spain; Capote, R. [IAEA-Vienna, Austria and Universidad de Sevilla, Spain; Carrapico, C. [Instituto Tecnológico e Nuclear (ITN), Lisbon, Portugal; Carrillo de Albornoz, A. [Instituto Tecnológico e Nuclear (ITN), Lisbon, Portugal; Cennini, P. [CERN, Geneva, Switzerland; Chepel, V. [University of Ciombra, Portugal; Chiaveri, E. [CERN, Geneva, Switzerland; Cortes, G. [Universitat Politecnica de Catalunya, Barcelona, Spain; Couture, A. [University of Notre Dame, IN; Cox, J. [University of Notre Dame, IN; Dahlfors, M. [CERN, Geneva, Switzerland; David, S. [CNRS, Orsay, France; Dillmann, I. [Institut fur Kernphysik, Karlsruhe, Germany; Dolfini, R. [Universita di Pavia, Italy; Domingo-Pardo, C. [CSIC-Universidad de Valencia; Koehler, Paul [ORNL; The n_TOF Collaboration, [CERN, Geneva, Switzerland

    2012-01-01

    Neutron-induced fission cross section measurements of 233U, 243Am and 241Am relative to 235U have been carried out at the neutron time-of-flight facility n TOF at CERN. A fast ionization chamber has been employed. All samples were located in the same detector; therefore the studied elements and the reference 235U target are subject to the same neutron beam.

  12. Onsager equations and time dependent neutron transport

    International Nuclear Information System (INIS)

    The diffusion of neutrons following an abrupt, localized temperature fluctuation can be conducted in the framework of Onsager-type transport equations. Considering Onsager equations as a generalized Fick's law, time-dependent particle and energy 'generalized diffusion equations' can be obtained. Aim of the present paper is to obtain the time-dependent diffusion Onsager-type equations for the diffusion of neutrons and to apply them to simple trial cases to gain a feeling for their behaviour. (author)

  13. Experimental verification of neutron phenomenology in lead and of transmutation by adiabatic resonance crossing in accelerator driven systems A summary of the TARC Project at CERN

    International Nuclear Information System (INIS)

    The Transmutation by Adiabatic Resonance Crossing (TARC) experiment was carried out as PS211 at the CERN PS from 1996 to 1999. Energy and space distributions of spallation neutrons (produced by 2.5 and 3.57 GeV/c CERN proton beams) slowing down in a 3.3x3.3x3 m3 lead volume and neutron capture rates on long-lived fission fragments 99Tc and 129I demonstrate that Adiabatic Resonance Crossing (ARC) can be used to eliminate efficiently such nuclear waste and validate innovative simulation

  14. Experimental verification of neutron phenomenology in lead and of transmutation by adiabatic resonance crossing in accelerator driven systems A summary of the TARC Project at CERN

    Energy Technology Data Exchange (ETDEWEB)

    Abanades, A.; Aleixandre, J.; Andriamonje, S.; Angelopoulos, A.; Apostolakis, A.; Arnould, H.; Belle, E.; Bompas, C.A.; Brozzi, D.; Bueno, J.; Buono, S.; Carminati, F.; Casagrande, F.; Cennini, P.; Collar, J.I.; Cerro, E.; Moral, R.D.R.Del; Diez, S.; Dumps, L.; Eleftheriadis, C.; Embid, M.; Fernandez, R.; Galvez, J.; Garcia, J.; Geles, C.; Giorni, A.; Gonzalez, E.; Gonzalez, O.; Goulas, I.; Heuer, D.; Hussonnois, M.; Kadi, Y.; Karaiskos, P.; Kitis, G.; Klapisch, R.; Kokkas, P.; Lacoste, V.; Le Naour, C.; Lopez, C.; Loiseaux, J.M.; Martinez-Val, J.M.; Meplan, O.; Nifenecker, H.; Oropesa, J.; Papadopoulos, I.; Pavlopoulos, P.; Perez-Enciso, E.; Perez-Navarro, A.; Perlado, M.; Placci, A.; Poza, M.; Revol, J.-P. E-mail: Jean-Pierre.Revol@cern.ch; Rubbia, C.; Rubio, J.A.; Sakelliou, L.; Saldana, F.; Savvidis, E.; Schussler, F.; Sirvent, C.; Tamarit, J.; Trubert, D.; Tzima, A.; Viano, J.B.; Vieira, S.; Vlachoudis, V.; Zioutas, K

    2001-05-11

    The Transmutation by Adiabatic Resonance Crossing (TARC) experiment was carried out as PS211 at the CERN PS from 1996 to 1999. Energy and space distributions of spallation neutrons (produced by 2.5 and 3.57 GeV/c CERN proton beams) slowing down in a 3.3x3.3x3 m{sup 3} lead volume and neutron capture rates on long-lived fission fragments {sup 99}Tc and {sup 129}I demonstrate that Adiabatic Resonance Crossing (ARC) can be used to eliminate efficiently such nuclear waste and validate innovative simulation.

  15. Real-Time Neutron Radiography at CARR

    Institute of Scientific and Technical Information of China (English)

    HE; Lin-feng; HAN; Song-bai; WANG; Hong-li; WU; Mei-mei; WEI; Guo-hai; WANG; Yu

    2012-01-01

    <正>A real-time detector system for neutron radiography based on CMOS camera has been designed for the thermal neutron imaging facility under construction at China Advanced Research Reactor (CARR). This system is equipped with a new scientific CMOS camera with 5.5 million pixels and speed up to 100 fps at full frame. The readout noise is less than 2.4 electron per pixel. It is capable of providing

  16. Determination of neutron generation time in miniature neutron source reactor by measurement of neutronics transfer function

    Energy Technology Data Exchange (ETDEWEB)

    Hainoun, A.; Khamis, I. [Atomic Energy Commission, Damascus (Syria). Dept. of Physics

    2000-02-01

    The prompt neutron generation time {lambda} and the total effective fraction of delayed neutrons (including the effect of photoneutrons) {beta} have been experimentally determined for the miniature neutron source reactor (MNSR) of Syria. The neutron generation time was found by taking measurements of the reactor open-loop transfer function using newly devised reactivity-step-ejection method by the reactor pneumatic rabbit system. Small reactivity perturbations i.e. step changes of reactivity starting from steady state, were introduced into the reactor during operation at low power level i.e. zero-power. Relative neutron flux and reactivity versus time were obtained. Using transfer function analysis as well as least square fitting techniques and measuring the delayed neutrons fraction, the neutron generation time was determined to be 74.6{+-}1.57 {mu}s. Using the prompt jump approximation of neutron flux, the total effective fraction of delayed neutrons was measured and found to be 0.00783{+-}0.00017. Measured values of {lambda} and {beta} were found to be very consistent with calculated ones reported in the safety analysis report. (orig.)

  17. Determination of neutron generation time in miniature neutron source reactor by measurement of neutronics transfer function

    International Nuclear Information System (INIS)

    The prompt neutron generation time Λ and the total effective fraction of delayed neutrons (including the effect of photoneutrons) β have been experimentally determined for the miniature neutron source reactor (MNSR) of Syria. The neutron generation time was found by taking measurements of the reactor open-loop transfer function using newly devised reactivity-step-ejection method by the reactor pneumatic rabbit system. Small reactivity perturbations i.e. step changes of reactivity starting from steady state, were introduced into the reactor during operation at low power level i.e. zero-power. Relative neutron flux and reactivity versus time were obtained. Using transfer function analysis as well as least square fitting techniques and measuring the delayed neutrons fraction, the neutron generation time was determined to be 74.6±1.57 μs. Using the prompt jump approximation of neutron flux, the total effective fraction of delayed neutrons was measured and found to be 0.00783±0.00017. Measured values of Λ and β were found to be very consistent with calculated ones reported in the safety analysis report. (orig.)

  18. Time reversal invariance in polarized neutron decay

    International Nuclear Information System (INIS)

    An experiment to measure the time reversal invariance violating (T-violating) triple correlation (D) in the decay of free polarized neutrons has been developed. The detector design incorporates a detector geometry that provides a significant improvement in the sensitivity over that used in the most sensitive of previous experiments. A prototype detector was tested in measurements with a cold neutron beam. Data resulting from the tests are presented. A detailed calculation of systematic effects has been performed and new diagnostic techniques that allow these effects to be measured have been developed. As the result of this work, a new experiment is under way that will improve the sensitivity to D to 3 x 10-4 or better. With higher neutron flux a statistical sensitivity of the order 3 x 10-5 is ultimately expected. The decay of free polarized neutrons (n → p + e + bar ve) is used to search for T-violation by measuring the triple correlation of the neutron spin polarization, and the electron and proton momenta (σn · pp x pe). This correlation changes sign under reversal of the motion. Since final state effects in neutron decay are small, a nonzero coefficient, D, of this correlation indicates the violation of time reversal invariance. D is measured by comparing the numbers of coincidences in electron and proton detectors arranged symmetrically about a longitudinally polarized neutron beam. Particular care must be taken to eliminate residual asymmetries in the detectors or beam as these can lead to significant false effects. The Standard Model predicts negligible T-violating effects in neutron decay. Extensions to the Standard Model include new interactions some of which include CP-violating components. Some of these make first order contributions to D

  19. Characterization of extended range Bonner Sphere Spectrometers in the CERF high-energy broad neutron field at CERN

    Science.gov (United States)

    Agosteo, S.; Bedogni, R.; Caresana, M.; Charitonidis, N.; Chiti, M.; Esposito, A.; Ferrarini, M.; Severino, C.; Silari, M.

    2012-12-01

    controlled workplace field. The CERF (CERN-EU high-energy reference field) facility is a unique example of such a field, where a number of experimental campaigns and Monte Carlo simulations have been performed over the past years. With the aim of performing this kind of workplace performance test, four different ERBSS with different degrees of validation, operated by three groups (CERN, INFN-LNF and Politecnico of Milano), were exposed in two fixed positions at CERF. Using different unfolding codes (MAXED, GRAVEL, FRUIT and FRUIT SGM), the experimental data were analyzed to provide the neutron spectra and the related dosimetric quantities. The results allow assessing the overall performance of each ERBSS and of the unfolding codes, as well as comparing the performance of three ERRCs when used in a neutron field with energy distribution different from the calibration spectrum.

  20. Time-energy relation of the n{sub T}OF neutron beam: energy standards revisited

    Energy Technology Data Exchange (ETDEWEB)

    Lorusso, G.; Colonna, N. E-mail: nicola.colonna@ba.infn.it; Marrone, S.; Tagliente, G.; Heil, M.; Cano-Ott, D.; Mosconi, M.; Moreau, C.; Mengoni, A.; Abbondanno, U.; Aerts, G.; Alvarez-Pol, H.; Alvarez-Velarde, F.; Andriamonje, S.; Andrzejewski, J.; Angelopoulos, A.; Assimakopoulos, P.; Badurek, G.; Baumann, P.; Becvar, F.; Benlliure, J.; Berthomieux, E.; Bisceglie, E.; Calvino, P.; Capote, R.; Cennini, P.; Chepel, V.; Chiaveri, E.; Coceva, C.; Cortes, G.; Cortina, D.; Couture, A.; Cox, J.; Dababneh, S.; Dahlfors, M.; David, S.; Dolfini, R.; Domingo-Pardo, C.; Duran, I.; Eleftheriadis, C.; Embid-Segura, M.; Ferrant, L.; Ferrari, A.; Ferreira-Marques, R.; Frais-Koelbl, H.; Furman, W.I.; Goncalves, I.F.; Gonzalez-Romero, E.; Goverdovski, A.; Gramegna, F.; Griesmayer, E.; Gunsing, F.; Haas, B.; Haight, R.; Herrera-Martinez, A.; Ioannides, K.G.; Isaev, S.; Jericha, E.; Kaeppeler, F.; Kadi, Y.; Karamanis, D.; Ketlerov, V.; Kitis, G.; Koehler, P.E.; Konovalov, V.; Kossionides, E.; Krticka, M.; Leeb, H.; Lindote, A.; Lopes, M.I.; Lozano, M.; Lukic, S.; Marganiec, J.; Mastinu, P.F.; Milazzo, P.M.; Molina-Coballes, A.; Neves, F.; Oberhummer, H.; O' Brien, S.; Pancin, J.; Paradela, C.; Pavlik, A.; Pavlopoulos, P.; Perrot, L.; Peskov, V.; Plag, R.; Plompen, A.; Plukis, A.; Poch, A.; Policarpo, A.; Pretel, C.; Quesada, J.M.; Rapp, W.; Rauscher, T.; Reifarth, R.; Rosetti, M.; Rubbia, C.; Rudolf, G.; Rullhusen, P.; Salgado, J.; Savvidis, E.; Soares, J.C.; Stephan, C.; Tain, J.L.; Tassan-Got, L.; Tavora, L.M.N.; Terlizzi, R.; Tsangas, N.; Vannini, G.; Vaz, P.; Ventura, A.; Villamarin, D.; Vincente, M.C.; Vlachoudis, V.; Vlastou, R.; Voss, F.; Wendler, H.; Wiescher, M.; Wisshak, K

    2004-10-21

    The accurate determination of neutron cross-sections as a function of the neutron energy at a time-of-flight facility requires a precise knowledge of the time-energy relation for the neutron beam. For the n{sub T}OF neutron beam at CERN, produced by spallation of high-energy protons on a Pb target, the time-energy relation is connected to the production mechanism and to the subsequent moderation process. A calibration of the neutron energy scale is proposed based on detailed Monte Carlo simulations of the facility. This time-energy relation has been experimentally validated by means of dedicated measurements of standard energy resonances, from 1 eV to approximately 1 MeV. On the basis of the present measurements, it is proposed to correct the energy of the 1.3 eV resonance of {sup 193}Ir, which is commonly considered as an energy standard.

  1. Characterization of extended range Bonner Sphere Spectrometers in the CERF high-energy broad neutron field at CERN

    International Nuclear Information System (INIS)

    controlled workplace field. The CERF (CERN-EU high-energy reference field) facility is a unique example of such a field, where a number of experimental campaigns and Monte Carlo simulations have been performed over the past years. With the aim of performing this kind of workplace performance test, four different ERBSS with different degrees of validation, operated by three groups (CERN, INFN-LNF and Politecnico of Milano), were exposed in two fixed positions at CERF. Using different unfolding codes (MAXED, GRAVEL, FRUIT and FRUIT SGM), the experimental data were analyzed to provide the neutron spectra and the related dosimetric quantities. The results allow assessing the overall performance of each ERBSS and of the unfolding codes, as well as comparing the performance of three ERRCs when used in a neutron field with energy distribution different from the calibration spectrum.

  2. CERN Rocks

    CERN Multimedia

    2004-01-01

    The 15th CERN Hardronic Festival took place on 17 July on the terrace of Rest 3 (Prévessin). Over 1000 people, from CERN and other International Organizations, came to enjoy the warm summer night, and to watch the best of the World's High Energy music. Jazz, rock, pop, country, metal, blues, funk and punk blasted out from 9 bands from the CERN Musiclub and Jazz club, alternating on two stages in a non-stop show.  The night reached its hottest point when The Canettes Blues Band got everybody dancing to sixties R&B tunes (pictured). Meanwhile, the bars and food vans were working at full capacity, under the expert management of the CERN Softball club, who were at the same time running a Softball tournament in the adjacent "Higgs Field". The Hardronic Festival is the main yearly CERN music event, and it is organized with the support of the Staff Association and the CERN Administration.

  3. TORCH - Cherenkov and Time-of-Flight PID Detector for the LHCb Upgrade at CERN

    Science.gov (United States)

    Föhl, K.; Brook, N.; Castillo García, L.; Conneely, T.; Cussans, D.; Forty, R.; Frei, C.; Gao, R.; Gys, T.; Harnew, N.; Milnes, J.; Piedigrossi, D.; Rademacker, J.; Ros Garcì a, A.; van Dijk, M.

    2016-05-01

    TORCH is a large-area precision time-of-flight detector, based on Cherenkov light production and propagation in a quartz radiator plate, which is read out at its edges. TORCH is proposed for the LHCb experiment at CERN to provide positive particle identification for kaons, and is currently in the Research-and-Development phase. A brief overview of the micro-channel plate photon sensor development, the custom-made electronics, and an introduction to the current test beam activities is given. Optical readout solutions are presented for the potential use of BaBar DIRC bar boxes as part of the TORCH configuration in LHCb.

  4. Time collimation for elastic neutron scattering at a pulsed source

    International Nuclear Information System (INIS)

    Conditions for carrying out elastic neutron scattering experiments using the time-of-flight technique are considered. It is shown, that the employment of time dependent neutron beam collimation in the source-sample flight path increases the luminosity of the spectrometer under certain resolution restrictions. Time collimation modes are proposed for small-angle scattering and neutron reflection. (author) 8 figs., 3 refs

  5. Correlation Time-of-flight Spectrometry of Ultracold Neutrons

    OpenAIRE

    Novopoltsev, M. I.; Pokotilovski, Yu. N.

    2010-01-01

    The fearures of the correlation method used in time-of-flight spectrometry of ultracold neutrons are analyzed. The time-of-flight spectrometer for the energy range of ultracold neutrons is described, and results of its testing by measuring spectra of neutrons passing through interference filters are presented.

  6. Measurement of Neutron Induced Fission of 235U, 233U and 245Cm with the FIC Detector at the CERN n()TOF Facility

    International Nuclear Information System (INIS)

    A series of measurements of neutron induced fission cross section of various TRU isotopes have been performed at the CERN n()TOF spallation neutron facility, in the energy range from thermal to nearly 250 MeV. The experimental apparatus consists in a fast ionization chamber (FIC), used as a fission fragment detector with a high efficiency. Good discrimination between alphas and fission fragments can be obtained with a simple amplitude threshold. In order to allow the monitoring of the neutron beam and to extract the n()TOF neutron flux, the well known cross section of the 235U(n,f) reaction, considered as a fission standard, has been used. Preliminary results for the cross section are shown for some selected isotopes such as 235U, 233U and 245Cm in the energy range from 0.050 eV to about 2 MeV.

  7. Onset of collectivity in neutron-rich Sr and Kr isotopes: Prompt spectroscopy after Coulomb excitation at REX-ISOLDE, CERN

    Directory of Open Access Journals (Sweden)

    Clément E.

    2013-12-01

    Full Text Available A rapid onset of quadrupole deformation is known to occur around the neutron number 60 in the neutron-rich Zr and Sr isotopes. This shape change has made the neutron-rich A = 100 region an active area of experimental and theoretical studies for many decades now. We report in this contribution new experimental results in the neutron rich 96,98Sr investigated by safe Coulomb excitation of radioactive beams at the REX-ISOLDE facility, CERN. Reduced transition probabilities and spectroscopic quadrupole moments have been extracted from the differential Coulomb excitation cross section supporting the scenario of shape coexistence/change at N = 60. Future perspectives are presented including the recent experimental campaign performed at ILL-Grenoble.

  8. Development of the high sensitivity real-time neutron radiography for low-flux neutron sources

    International Nuclear Information System (INIS)

    The authors have developed a high-sensitivity real-time neutron radiography (NR) system by the use of the low power reactor of Kinki University. The system was constructed with a high efficiency neutron-photon converter, an image intensifier and a SIT TELEVISION camera. Some digital image processing techniques were applied for improving the quality of the real-time neutron images. By the use of this system, dynamic neutron imaging was performed successfully under the condition of a weak neutron field that was about two orders of magnitude lower than that of the standard NR system. The neutron flux, calculated from the fluctuation of the neutron response of the images, was nearly equal to the value measured by the foil activation method. From this fact, the efficiency for the neutron detection of the imaging system was estimated to be almost 100%. For the purpose of developing a system with higher sensitivity, consideration of neutron statistics would be important. (author)

  9. Measurement and analysis of the $^{243}$Am neutron capture cross section at the n_TOF facility at CERN

    CERN Document Server

    Mendoza, E; Guerrero, C; Berthoumieux, E; Abbondanno, U; Aerts, G; Alvarez-Velarde, F; Andriamonje, S; Andrzejewski, J; Assimakopoulos, P; Audouin, L; Badurek, G; Balibrea, J; Baumann, P; Becvar, F; Belloni, F; Calvino, F; Calviani, M; Capote, R; Carrapico, C; Carrillo de Albornoz, A; Cennini, P; Chepel, V; Chiaveri, E; Colonna, N; Cortes, G; Couture, A; Cox, J; Dahlfors, M; David, S; Dillmann, I; Dolfini, R; Domingo-Pardo, C; Dridi, W; Duran, I; Eleftheriadis, C; Ferrant†, L; Ferrari, A; Ferreira-Marques, R; Fitzpatrick, L; Frais-Koelbl, H; Fujii, K; Furman, W; Goncalves, I; Gonz alez-Romero, E; Goverdovski, A; Gramegna, F; Griesmayer, E; Gunsing, F; Haas, B; Haight, R; Heil, M; Herrera-Martinez, A; Igashira, M; Isaev, S; Jericha, E; Kappeler, F; Kadi, Y; Karadimos, D; Karamanis, D; Ketlerov, V; Kerveno, M; Koehler, P; Konovalov, V; Kossionides, E; Krticka, M; Lampoudis, C; Leeb, H; Lindote, A; Lopes, I; Lossito, R; Lozano, M; Lukic, S; Marganiec, J; Marques, L; Marrone, S; Martınez, T; Massimi, C; Mastinu, P; Mengoni, A; Milazzo, P M; Moreau, C; Mosconi, M; Neves, F; Oberhummer, H; O’Brien, S; Oshima, M; Pancin, J; Papachristodoulou, C; Papadopoulos, C; Paradela, C; Patronis, N; Pavlik, A; Pavlopoulos, P; Perrot, L; Pigni, M T; Plag, R; Plompen, A; Plukis, A; Poch, A; Praena, J; Pretel, C; Quesada, J; Rauscher, T; Reifarth, R; Rosetti, M; Rubbia, C; Rudolf, G; Rullhusen, P; Salgado, J; Santos, C; Sarchiapone, L; Savvidis, I; Stephan, C; Tagliente, G; Tain, J L; Tassan-Got, L; Tavora, L; Terlizzi, R; Vannini, G; Vaz, P; Ventura, A; Villamarin, D; Vicente, M C; Vlachoudis, V; Vlastou, R; Voss, F; Walter, S; Wendler, H; Wiescher, M; Wisshak, K

    2014-01-01

    Background:The design of new nuclear reactors and transmutation devices requires to reduce the present neutron cross section uncertainties of minor actinides. Purpose: Reduce the $^{243}$Am(n,$\\gamma$) cross section uncertainty. Method: The $^{243}$Am(n,$\\gamma$) cross section has been measured at the n_TOF facility at CERN with a BaF$_{2}$ Total Absorption Calorimeter, in the energy range between 0.7 eV and 2.5 keV. Results: The $^{243}$Am(n,$\\gamma$) cross section has been successfully measured in the mentioned energy range. The resolved resonance region has been extended from 250 eV up to 400 eV. In the unresolved resonance region our results are compatible with one of the two incompatible capture data sets available below 2.5 keV. The data available in EXFOR and in the literature has been used to perform a simple analysis above 2.5 keV. Conclusions: The results of this measurement contribute to reduce the $^{243}$Am(n,$\\gamma$) cross section uncertainty and suggest that this cross section is underestimate...

  10. CERN-group conceptual design of a fast neutron operated high power energy amplifier

    International Nuclear Information System (INIS)

    The practical feasibility of an Energy Amplifier (EA) with power and power density which are comparable to the ones of the present generation of large PWR is discussed in this paper. This is only possible with fast neutrons. Schemes are described which offer a high gain, a large maximum power density and an extended burn-up, well in excess of 100 GW x d/t corresponding to about five years at full power operation with no intervention on the fuel core. The following topics are discussed: physics considerations and parameter definition, the accelerator complex, the energy amplifier unit, computer simulated operation, and fuel cycle closing

  11. Quantitative time resolved neutron imaging methods at the high flux neutron source FRM-II

    OpenAIRE

    Brunner, Johannes

    2007-01-01

    In the current work various new experimental methods and computation procedures in the field of neutron imaging are presented. These methods have a significant technical importance in non-destructive material investigations. With stroboscopic neutron radiography periodic processes can be investigated on a sub-millisecond time scale. This opens great opportunities for the study and the development of combustion engines. Energy selective time of flight neutron radiography at neutron spallation ...

  12. The CERN Library

    CERN Multimedia

    Hester, Alec G

    1968-01-01

    Any advanced research centre needs a good Library. It can be regarded as a piece of equipment as vital as any machine. At the present time, the CERN Library is undergoing a number of modifications to adjust it to the changing scale of CERN's activities and to the ever increasing flood of information. This article, by A.G. Hester, former Editor of CERN COURIER who now works in the Scientific Information Service, describes the purposes, methods and future of the CERN Library.

  13. Real time neutron image processing system in NRF

    International Nuclear Information System (INIS)

    The neutron radiography facility was installed at the neutron radiography beam tube of the HANARO research reactor. The NRF is used for the nondestructive test to inspect and evaluate the material defect and homogeneity by detecting the transmitted neutron image in the nuclear as well as non-nuclear industry. To analyze the dynamical neutron image effectively and efficiently, the real-time image processing system was developed in background subtraction, normalization, geometry correction and beam uniformity, contrast control, filtering. The image quality test and dimension measurements were performed for the neutron beam purity and sensitivity indication. The NRF beam condition represents the highest beam quality for neutron radiography.

  14. Development of Upgraded Magnetic Instrumentation for CERN Real-Time Reference Field Measurement Systems

    CERN Document Server

    Buzio, M; Galbraith, P; Golluccio, G; Giloteaux, D; Gilardoni, S; Petrone, C; Walckiers, L

    2010-01-01

    The control of five of the accelerators in the CERN injector chain (PS, PS Booster, SPS, LEIR and AD) is based upon real-time measurements in a reference magnet. These so-called “B-train” systems include a field marker to signal the achievement of a given field value, complemented by one or more pick-up coils to integrate flux changes. Recently, some concerns were raised about long-term reliability and performance improvements, in terms of both resolution and operational flexibility, for these systems. This paper reports the status of three related R&D activities, namely: the development of a novel dynamic NMR field marker for the PS; a campaign aimed at the detailed measurement of the magnetic state of a PS main magnet; and the design of a standardized electronic signal acquisition and conditioning system.

  15. Real time analysis of light water core neutronics

    International Nuclear Information System (INIS)

    A method is described for determining the neutronics parameters of a reactor core comprising the steps of: representing the reactor core as a plurality of nodes having a coarse nodal representation; monitoring selected neutronic parameters of the reactor core; providing time-dependent two group neutron diffusion equations coupled to delayed neutron precursor concentrations that have been subjected to space-time factorization by shape and amplitude functions in response to the plurality of nodes; sensing the monitored parameters; and determining the core neutronics parameters in response to the sensed parameters and the provided two group neutron diffusion equations in constant time steps for sensing the monitored parameters and determining the core neutronics parameters in a real-time environment, the time steps being not less than one quarter second

  16. Measurement of the Syrian MNSR delayed neutron fraction and neutron generation time by noise analysis

    Energy Technology Data Exchange (ETDEWEB)

    Khamis, I. E-mail: ikhamis@aec.org.sy; Hainoun, A.; Suleiman, W

    2003-02-01

    Delayed neutron fraction {beta} and prompt neutron generation time {lambda} were determined for the Miniature Neutron Source Reactor of Syria using noise analysis technique. Small reactivity perturbations, step-wise and impulse in time, were introduced into the reactor at low power level i.e. zero-power. Power and reactivity versus time were obtained. Using the generalized least square algorithm and transfer function analysis, measurement of both the delayed neutron fraction and the neutron generation time were made. The MNSR values obtained for the prompt neutron generation time and delayed neutron fraction are 78.3{+-}1.3 {mu}s and 7.94{+-}0.11x10{sup -3} respectively. Both measured values of {beta} and {lambda} were found to be very consistent with previously measured and calculated ones reported in the Safety Analysis Report.

  17. Measurement of the Syrian MNSR delayed neutron fraction and neutron generation time by noise analysis

    International Nuclear Information System (INIS)

    Delayed neutron fraction β and prompt neutron generation time Λ were determined for the Miniature Neutron Source Reactor of Syria using noise analysis technique. Small reactivity perturbations, step-wise and impulse in time, were introduced into the reactor at low power level i.e. zero-power. Power and reactivity versus time were obtained. Using the generalized least square algorithm and transfer function analysis, measurement of both the delayed neutron fraction and the neutron generation time were made. The MNSR values obtained for the prompt neutron generation time and delayed neutron fraction are 78.3±1.3 μs and 7.94±0.11x10-3 respectively. Both measured values of β and Λ were found to be very consistent with previously measured and calculated ones reported in the Safety Analysis Report

  18. Measurement of the Syrian MNSR delayed neutron fraction and neutron generation time by noise analysis

    International Nuclear Information System (INIS)

    Delayed neutron fraction beta and prompt neutron generation time LAMBDA were determined for the Miniature Neutron Source Reactor of Syria using noise analysis technique. Small reactivity perturbations, step-wise and impulse in time, were introduced into the reactor at low power level i.e. zero-power. Power and reactivity versus time were obtained. Using the generalized least square algorithm and transfer function analysis, measurement of both the delayed neutron fraction and the neutron generation time were made. The MNSR values obtained for the prompt neutron generation time and delayed neutron fraction are 78.3+-1.3 mu s and 7.94+-0.11x10 sup - sup 3 respectively. Both measured values of beta and LAMBDA were found to be very consistent with previously measured and calculated once reported in the Safety Analysis Report. (author)

  19. Texture Investigations by Neutron Time-of-Flight Diffraction

    OpenAIRE

    Feldmann, K.

    1989-01-01

    For the majority of isotopes the thermal neutron absorption cross section is two or more orders lower than that for X-rays. This makes neutron diffraction well-suited for bulk texture investigations. Some characteristics of neutron diffraction are discussed. The principles of neutron time-of-flight diffraction are described. The pole figure determination by means of TOF technique is considered. The main parameters of the present Dubna texture facility are given. Further developments of the ex...

  20. Time reversal tests in nuclear and neutron beta decay

    International Nuclear Information System (INIS)

    Motivation for time reversal violation studies in nuclear and neutron weak decay is discussed with an emphasis on searches for the exotic tensor and scalar weak interaction. The results of the experiment with polarized 8Li are updated. A new experiment with the aim to determine the transverse polarization of electrons emitted by free, polarized neutrons, is proposed. A facility for neutron decay studies with polarized cold neutrons is under construction at the spallation source SINQ-PSI

  1. Analyzer of neutron flux in real time

    International Nuclear Information System (INIS)

    With base in the study of the real signals of neutron flux of instability events occurred in the Laguna Verde nuclear power plant where the nucleus oscillation phenomena of the reactor are in the 0 to 2.5 Hz range, it has been seen the possibility about the development a surveillance and diagnostic equipment capable to analyze in real time the behavior of nucleus in this frequencies range. An important method for surveillance the stability of the reactor nucleus is the use of the Power spectral density which allows to determine the frequencies and amplitudes contained in the signals. It is used an instrument carried out by LabVIEW graphic programming with a data acquisition card of 16 channels which works at Windows 95/98 environment. (Author)

  2. Precision measurements with the multi-reflection time-of-flight mass spectrometer of ISOLTRAP at ISOLDE/CERN

    Energy Technology Data Exchange (ETDEWEB)

    Atanasov, Dinko; Ascher, Pauline; Borgmann, Christopher; Boehm, Christine; Eliseev, Sergey; Eronen, Tommi; George, Sebastian; Kisler, Dmitry; Naimi, Sarah [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany); Beck, Dietrich; Herfurth, Frank; Litvinov, Yuri; Minaya Ramirez, Enrique; Neidherr, Dennis [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Planckstr. 1, 64291 Darmstadt (Germany); Breitenfeldt, Martin [Instituut voor Kern- en Stralingsfysica, Celestijnenlaan 200d - bus 2418, 3001 Heverlee (Belgium); Cakirli, Burcu [University of Istanbul, Department of Physics, 34134 Istanbul (Turkey); Cocolios, Thomas Elias [University of Manchester, Manchester (United Kingdom); Herlert, Alexander Josef [FAIR GmbH, Planckstr. 1, D-64291 Darmstadt (Germany); Kowalska, Magdalena [CERN, Geneva 23, 1211 Geneva (Switzerland); Kreim, Susanne [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany); CERN, Geneva 23, 1211 Geneva (Switzerland); Lunney, David; Manea, Vladimir [CSNSM-IN2P3-CNRS, 91405 Orsay Campus, Bat. 104, 108 (France); Rosenbusch, Marco; Schweikhard, Lutz; Wienholtz, Frank; Wolf, Robert [Ernst-Moritz-Arndt-Universitaet, Institut fuer Physik, Felix-Hausdorff-Str. 6, 17487 Greifswald (Germany); Stanja, Juliane; Zuber, Kai [Institut fuer Kern- und Teilchenphysik, Technische Universitaet Dresden, Zellescher Weg 19, 01069 Dresden (Germany)

    2014-07-01

    The masses of exotic nuclides are among the most important input parameters for modern nuclear theory and astrophysical models. At the high-precision Penning-trap mass spectrometer ISOLTRAP at ISOLDE/CERN, a multi-reflection time-of-flight mass spectrometer (MR-ToF-MS) in combination with a Bradbury-Nielsen gate (BNG) can be used to achieve high-resolution isobar purification with mass-resolving powers of 105 in a few tens of milliseconds. Furthermore, the MR-ToF device can be used as a spectrometer to determine the masses of nuclides with very low yields and short half-lives, where a Penning-trap mass measurement becomes impractical due to the lower transport efficiency and decay losses during the purification and measurement cycles. Recent cross-check experiments show that the MR-ToF MS allows mass measurements with uncertainties in the sub-ppm range. In a first application the mass measurements of the nuclides 53,54Ca was performed, delivered with production rates as low as 10/s and half-lives of only 90(6) ms. The nuclides serve as important benchmarks for testing modern chiral effective theory with realistic 3-body forces. The contribution presents the on-line mass spectrometer ISOLTRAP focusing on the new applications, which became possible after the implementation of the MR-ToF MS into the current setup. In particular, the mass measurements of the neutron-rich calcium isotopes up to A=54 are discussed. In addition, measurements of the isotonic potassium isotopes are reported.

  3. Precision measurements with the multi-reflection time-of-flight mass spectrometer of ISOLTRAP at ISOLDE/CERN

    International Nuclear Information System (INIS)

    The masses of exotic nuclides are among the most important input parameters for modern nuclear theory and astrophysical models. At the high-precision Penning-trap mass spectrometer ISOLTRAP at ISOLDE/CERN, a multi-reflection time-of-flight mass spectrometer (MR-ToF-MS) in combination with a Bradbury-Nielsen gate (BNG) can be used to achieve high-resolution isobar purification with mass-resolving powers of 105 in a few tens of milliseconds. Furthermore, the MR-ToF device can be used as a spectrometer to determine the masses of nuclides with very low yields and short half-lives, where a Penning-trap mass measurement becomes impractical due to the lower transport efficiency and decay losses during the purification and measurement cycles. Recent cross-check experiments show that the MR-ToF MS allows mass measurements with uncertainties in the sub-ppm range. In a first application the mass measurements of the nuclides 53,54Ca was performed, delivered with production rates as low as 10/s and half-lives of only 90(6) ms. The nuclides serve as important benchmarks for testing modern chiral effective theory with realistic 3-body forces. The contribution presents the on-line mass spectrometer ISOLTRAP focusing on the new applications, which became possible after the implementation of the MR-ToF MS into the current setup. In particular, the mass measurements of the neutron-rich calcium isotopes up to A=54 are discussed. In addition, measurements of the isotonic potassium isotopes are reported.

  4. TIME INTERVAL APPROACH TO THE PULSED NEUTRON LOGGING METHOD

    Institute of Scientific and Technical Information of China (English)

    赵经武; 苏为宁

    1994-01-01

    The time interval of neibouring neutrons emitted from a steady state neutron source can be treated as that from a time-dependent neutron source,In the rock space.the neutron flux is given by the neutron diffusion equation and is composed of an infinite number of “modes”,EaCh“mode”,is composed of two die-away curves.The delay action has been discussed and used to measure the time interval with only one detector in the experiment,Nuclear reactions with the time distribution due to different types of radiations observed in the neutron well-logging methods are presented with a view to getting the rock nuclear parameters from the time interval technique.

  5. Future Perspectives at CERN

    OpenAIRE

    Ellis, John

    2002-01-01

    Current and future experiments at CERN are reviewed,with emphasis on those relevant to astrophysics and cosmology. These include experiments related to nuclear astrophysics, matter-antimatter asymmetry, dark matter, axions, gravitational waves, cosmic rays, neutrino oscillations, inflation, neutron stars and the quark-gluon plasma. The centrepiece of CERN's future programme is the LHC, but some ideas for perspectives after the LHC are also presented.

  6. Real time spectrometer for thermal neutrons from radiotherapic accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Mozzanica, A. [Universita degli Studi di Brescia e INFN sezione di Pavia (Italy)], E-mail: mozzanica@bs.infn.it; Bartesaghi, G.; Bolognini, D.; Conti, V.; Mascagna, V.; Prest, M.; Scazzi, S. [Universita degli Studi dell' Insubria e INFN sezione di Milano/Milano Bicocca (Italy); Cappelletti, P.; Frigerio, M.; Gelosa, S.; Monti, A.; Ostinelli, A. [Fisica Sanitaria, Ospedale S. Anna di Como (Italy); Bevilacqua, R.; Giannini, G.; Totaro, P.; Vallazza, E. [INFN, sezione di Trieste e Universita degli Studi di Trieste (Italy)

    2007-10-15

    Radiotherapy accelerators can produce high energy photon beams for deep tumour treatments. Photons with energies greater than 8 MeV produce neutrons via photoproduction. The PHONES (PHOto NEutron Source) project is developing a neutron moderator to use the photoproduced neutrons for BNCT (Boron Neutron Capture Therapy) in hospital environments. In this framework we are developing a real time spectrometer for thermal neutrons exploiting the bunch structure of the beam. Since the beam is produced by a linear accelerator, in fact, particles are sent to the patient in bunches with a rate of 150-300 Hz depending on the beam type and energy. The neutron spectrum is usually measured with integrating detectors such as bubble dosimeters or TLDs, which integrate over a time interval and an energy one. We are developing a scintillator detector to measure the neutron spectrum in real time in the interval between bunches, that is in the thermal region. The signals from the scintillator are discriminated and sampled by a dedicated clock in a Cyclone II FPGA by Altera, thus obtaining the neutron time of flight spectrum. The exploited physical process in ordinary plastic scintillators is neutron capture by H with a subsequent {gamma} emission. The measured TOF spectrum has been compared with a BF{sub 3} counter one. A dedicated simulation with MCNP is being developed to extract the energy spectrum from the TOF one. The paper will present the results of the prototype measurements and the status of the simulation.

  7. CERN Holiday Gift Guide

    CERN Multimedia

    2013-01-01

    Do you have last-minute gifts to get? Stuck for ideas? The CERN Shop and the ATLAS and CMS secretariats have some wonderfully unique gifts and stocking-fillers for sale this year - perfect for the physics fanatics in your life. Let's take a look...   1. CERN Notebook, 10 CHF - 2. CERN Pop-up book, 30 CHF - 3. USB Stick 8GB, 25 CHF - 4. CERN Tumbler, 12 CHF 5. ATLAS 3D Viewer, 5 CHF - 6. ATLAS Puzzle, 15 CHF - 7. CMS Umbrella, 25 CHF   These gifts are all available at the CERN Shop, with the exception of the ATLAS 3D Viewer and the CMS umbrella, which are only available from the respective secretariats. Don’t forget! If you’re from CERN, you still have time to take advantage of a 10% off discount at the CERN shop. Offer ends 20 December.

  8. Measurement of the neutron capture cross section of U{sup 234} in n-TOF at CERN for Generation IV nuclear reactors; Mesure de la section efficace de capture neutronique de l'{sup 234}U a n-TOF au CERN pour les reacteurs nucleaires de generation 4

    Energy Technology Data Exchange (ETDEWEB)

    Dridi, W

    2006-11-15

    Accurate and reliable neutron capture cross sections are needed in many research areas, including stellar nucleosynthesis, advanced nuclear fuel cycles, waste transmutation, and other applied programs. In particular, the accurate knowledge of U{sup 234}(n,{gamma}) reaction cross section is required for the design and realization of nuclear power plants based on the thorium fuel cycle. We have measured the neutron capture cross section of U{sup 234}, with a 4{pi} BaF{sub 2} Total Absorption Calorimeter, at the recently constructed neutron time-of-flight facility n-TOF at CERN in the energy range from 0.03 eV to 1 MeV. Monte-Carlo simulations with GEANT4 and MCNPX of the detector response have been performed. After the background subtraction and correction with dead time and pile-up, the capture yield from 0.03 eV up to 1.5 keV was derived. The analysis of the capture yield in terms of R-matrix resonance parameters is discussed. We have identified 123 resonances and measured the resonance parameters in the energy range from 0.03 eV to 1.5 keV. The mean radiative width <{gamma}{sub {gamma}}> is found to be (38.2 {+-} 1.5) meV and the mean spacing parameter is (11.0 {+-} 0.2) eV, both values agree well with recommended values.

  9. Mapping of the thermal neutron distribution in the lead block assembly of the PS-211 experiment at CERN, using thermoluminescence and nuclear track detectors

    CERN Document Server

    Savvidis, E; Kitis, G

    2002-01-01

    The main purpose of the TARC (transmutation by adiabatic resonance crossing) experiment (PS-211), was to demonstrate the possibility to destroy efficiently long-lived fission fragments (LLFF) in accelerator driven systems (ADS). The experimental set-up which consisted of a lead block with dimensions 3.3 * 3.3 * 3 m/sup 3/, was installed in a CERN proton synchrotron (PS) beam line. The proton beam at 2.5 GeV/c and 3.5 GeV/c, was incident in the centre of the lead block assembly producing neutrons via spallation reactions. Neutron flux measurements are presented in the lead block assembly using thermoluminescence and nuclear track detectors. The results are in good agreement with Monte Carlo calculations as well as with the results of the other methods used in the framework of the TARC experiment. (5 refs).

  10. Time-gated energy-selected cold neutron radiography

    CERN Document Server

    McDonald, T E; Claytor, T N; Farnum, E H; Greene, G L; Morris, C

    1999-01-01

    A technique is under development at the Los Alamos Neutron Science Center (LANSCE), Manuel Lujan Jr. Neutron Scattering Center (Lujan Center) for producing neutron radiography using only a narrow energy range of cold neutrons. The technique, referred to as time-gated energy-selected (TGES) neutron radiography, employs the pulsed neutron source at the Lujan Center with time of flight to obtain a neutron pulse having an energy distribution that is a function of the arrival time at the imager. The radiograph is formed on a short persistence scintillator and a gated, intensified, cooled CCD camera is employed to record the images, which are produced at the specific neutron energy range determined by the camera gate. The technique has been used to achieve a degree of material discrimination in radiographic images. For some materials, such as beryllium and carbon, at energies above the Bragg cutoff the neutron scattering cross section is relatively high while at energies below the Bragg cutoff the scattering cross ...

  11. Study of calculated and measured time dependent delayed neutron yields

    International Nuclear Information System (INIS)

    Time-dependent delayed neutron emission is of interest in reactor design, reactor dynamics, and nuclear physics studies. The delayed neutrons from neutron-induced fission of 232U, 237Np, 238Pu, 241Am, /sup 242m/Am, 245Cm, and 249Cf were studied for the first time. The delayed neutron emission from 232Th, 233U, 235U, 238U, 239Pu, 241Pu, and 242Pu were measured as well. The data were used to develop an empirical expression for the total delayed neutron yield. The expression gives accurate results for a large variety of nuclides from 232Th to 252Cf. The data measuring the decay of delayed neutrons with time were used to derive another empirical expression predicting the delayed neutron emission with time. It was found that nuclides with similar mass-to-charge ratios have similar decay patterns. Thus the relative decay pattern of one nuclide can be established by any measured nuclide with a similar mass-to-charge ratio. A simple fission product yield model was developed and applied to delayed neutron precursors. It accurately predicts observed yield and decay characteristics. In conclusion, it is possible to not only estimate the total delayed neutron yield for a given nuclide but the time-dependent nature of the delayed neutrons as well. Reactors utilizing recycled fuel or burning actinides are likely to have inventories of fissioning nuclides that have not been studied until now. The delayed neutrons from these nuclides can now be incorporated so that their influence on the stability and control of reactors can be delineated. 8 figures, 39 tables

  12. Time-resolved fast neutron imaging: simulation of detector performance

    International Nuclear Information System (INIS)

    We have analyzed and compared the performance of two novel fast-neutron imaging methods with time-of-flight spectroscopy capability. Key parameters such as detection efficiency, the amount of energy deposited in the converter and the spatial resolution of both detector variants have been simulated by means of neutron and charged-particle transport codes

  13. Time-resolved fast neutron imaging: simulation of detector performance

    OpenAIRE

    Vartsky, D.; Mor, I.; Goldberg, M B; Mardor, I.; Feldman, G.; Bar, D.; A. Shor; Dangendorf, V.; Laczko, G; Breskin, A.; Chechik, R.

    2004-01-01

    We have analyzed and compared the performance of two novel fast-neutron imaging methods with time-of-flight spectroscopy capability. Using MCNP and GEANT code simulations of neutron and charged-particle transport in the detectors, key parameters such as detection efficiency, the amount of energy deposited in the converter and the spatial resolution of both detector variants have been evaluated.

  14. Optimization of ''reverse time of flight'' neutron scattering devices

    International Nuclear Information System (INIS)

    The ''reverse time of flight'' (RTOF) elastic neutron scattering technique for powdered samples is briefly described. The advantages and some problems of this high resolution technique are discussed. The main task is to illustrate opportunities and solutions for an optimization of a RTOF instrument, especially for the neutron chopper device and the detector system. (orig.)

  15. Measurement of neutron induced fission of {sup 235}U, {sup 233}U and {sup 245}Cm with the FIC detector at the CERN n-TOF facility

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-07-01

    A series of measurements of neutron induced fission cross section of various transuranic isotopes have been performed at the CERN n-TOF spallation neutron facility, in the energy range from thermal to nearly 250 MeV. The experimental apparatus consists in a fast ionization chamber (FIC), used as a fission fragment detector with a high efficiency. Good discrimination between alphas and fission fragments can be obtained with a simple amplitude threshold. In order to allow the monitoring of the neutron beam and to extract the n-TOF neutron flux, the well known cross section of the {sup 235}U(n,f) reaction, considered as a fission standard, has been used. Preliminary results for the cross section are shown for some selected isotopes such as {sup 235}U, {sup 233}U and {sup 245}Cm in the energy range from 0.050 eV to about 2 MeV. These results for {sup 235}U, {sup 233}U and {sup 245}Cm show results consistent with databases in the resonance region, with no normalization required for {sup 233}U. In the case of {sup 245}Cm, for the energy range between thermal and 20 eV, we obtained the first experimental data ever published, while showing a good agreement with previous data in the region above that value.

  16. Measurement of neutron induced fission of 235U, 233U and 245Cm with the FIC detector at the CERN n-TOF facility

    International Nuclear Information System (INIS)

    A series of measurements of neutron induced fission cross section of various transuranic isotopes have been performed at the CERN n-TOF spallation neutron facility, in the energy range from thermal to nearly 250 MeV. The experimental apparatus consists in a fast ionization chamber (FIC), used as a fission fragment detector with a high efficiency. Good discrimination between alphas and fission fragments can be obtained with a simple amplitude threshold. In order to allow the monitoring of the neutron beam and to extract the n-TOF neutron flux, the well known cross section of the 235U(n,f) reaction, considered as a fission standard, has been used. Preliminary results for the cross section are shown for some selected isotopes such as 235U, 233U and 245Cm in the energy range from 0.050 eV to about 2 MeV. These results for 235U, 233U and 245Cm show results consistent with databases in the resonance region, with no normalization required for 233U. In the case of 245Cm, for the energy range between thermal and 20 eV, we obtained the first experimental data ever published, while showing a good agreement with previous data in the region above that value.

  17. Big research in new dimensions. Thinkers of our time about the actual elementary-particle physics at CERN

    International Nuclear Information System (INIS)

    The following topics are dealt with: Research from the highest energies to the smallest particles at CERN, the laborious way to the Large Hadronic Collider, CERN as accelerator of techniques, culture, and society, a philosophical and sociological perspective of questions concerning CERN, quark matter research at CERN, the FAIR facility for antiproton and ion research. (HSI)

  18. Real-Time Active Cosmic Neutron Background Reduction Methods

    Energy Technology Data Exchange (ETDEWEB)

    Mukhopadhyay, Sanjoy; Maurer, Richard; Wolff, Ronald; Mitchell, Stephen; Guss, Paul

    2013-09-01

    Neutron counting using large arrays of pressurized 3He proportional counters from an aerial system or in a maritime environment suffers from the background counts from the primary cosmic neutrons and secondary neutrons caused by cosmic ray-induced mechanisms like spallation and charge-exchange reaction. This paper reports the work performed at the Remote Sensing Laboratory–Andrews (RSL-A) and results obtained when using two different methods to reduce the cosmic neutron background in real time. Both methods used shielding materials with a high concentration (up to 30% by weight) of neutron-absorbing materials, such as natural boron, to remove the low-energy neutron flux from the cosmic background as the first step of the background reduction process. Our first method was to design, prototype, and test an up-looking plastic scintillator (BC-400, manufactured by Saint Gobain Corporation) to tag the cosmic neutrons and then create a logic pulse of a fixed time duration (~120 μs) to block the data taken by the neutron counter (pressurized 3He tubes running in a proportional counter mode). The second method examined the time correlation between the arrival of two successive neutron signals to the counting array and calculated the excess of variance (Feynman variance Y2F)1 in the neutron count distribution from Poisson distribution. The dilution of this variance from cosmic background values ideally would signal the presence of man-made neutrons.2 The first method has been technically successful in tagging the neutrons in the cosmic-ray flux and preventing them from being counted in the 3He tube array by electronic veto—field measurement work shows the efficiency of the electronic veto counter to be about 87%. The second method has successfully derived an empirical relationship between the percentile non-cosmic component in a neutron flux and the Y2F of the measured neutron count distribution. By using shielding materials alone, approximately 55% of the neutron flux

  19. Device for Writing the Time Tail from Spallation Neutron Pulses

    International Nuclear Information System (INIS)

    Recent work at Los Alamos Neutron Science Center (LANSCE), has shown that there are large gains in neutron beam intensity to be made by using coupled moderators at spallation neutron sources. Most of these gains result from broadening the pulse-width in time. However the accompanying longer exponential tail at large emission times can be a problem in that it introduces relatively large beam-related backgrounds at high resolutions. We have designed a device that can reshape the moderated neutron beam by cutting the time-tail so that a sharp time resolution can be re-established without a significant loss in intensity. In this work the basic principles behind the tail-cutter and some initial results of Monte Carlo simulations are described. Unwanted neutrons in the long time-tail are diffracted out of the transmitted neutron beam by a nested stack of aperiodic multi-layers, rocking at the same frequency as the source. Nested aperiodic multi-layers have recently been used at X-ray sources and as band-pass filters in quasi-Laue neutron experiments at reactor neutron sources. Optical devices that rock in synchronization with a pulsed neutron beam are relatively new but are already under construction at LANSCE. The tail-cutter described here is a novel concept that uses existing multi-layer technology in a new way for spallation neutrons. Coupled moderators in combination with beam shaping devices offer the means of increasing flux whilst maintaining a sharp time distribution. A prototype device is being constructed for the protein crystallography station at LANSCE. The protein crystallography station incorporates a water moderator that has been judiciously coupled in order to increase the flux over neutron energies that are important to structural biology (3-80meV). This development in moderator design is particularly important because protein crystallography is flux limited and because conventional ambient water and cold hydrogen moderators do not provide relatively

  20. Time-dependent pseudo-reciprocity relations in neutronics

    International Nuclear Information System (INIS)

    Earlier, certain reciprocity-like relations have been shown to hold in some restricted steady state cases in neutron diffusion and transport theories. Here, the possibility of existence of similar relations in time-dependent situations is investigated

  1. CERN Relay Race: the Shabbys win again, this time with music

    CERN Multimedia

    2005-01-01

    The Shabbys definitely seem unbeatable. They won the CERN Relay Race for the fifth consecutive year by a comfortable margin (picture below). It was a more neck-and-neck finish for second and third place but in the end Los Latinos Volantes came in second by a hair's breadth in front of Charmilles Technologies in third place, a reversal of last year's positions. For the less competitive participants, the Relay Race retains its traditional charm as a moment of relaxation and as an event in which taking part is more important than winning. In addition, even if the sun was noticeable by its absence, CERN's excellent Jazz Club band added a novel touch of colour and levity. Participants and spectators alike greatly appreciated their musical accompaniment on the finishing line! All the results are published in this issue on page 5 of the Staff Association section.

  2. CERN: Fixed target targets

    International Nuclear Information System (INIS)

    visible for the first time, and help explain the continuing dilemma of the dearth of solar neutrinos (December 1992, page 12). For the longer term future, a larger detector could provide an increased yield, boosting the neutrino capture rate by up to a factor of ten. Other, more spectacular, option is to shine the CERN neutrino beam towards a detector a long way off. Such a beam is practically unimpeded by matter and could pass right through the earth. Possible contenders for underground target stations equipped with big detectors are the Italian Gran Sasso laboratory, 730 kilometres south, or Superkamiokande, 8750 kilometres away in Japan. Other major ongoing 'flagship' SPS projects include the NA48 experiment to continue precision measurements on the still unexplained phenomenon of CP violation (March 1992, page 7) and the 'Spin Muon Collaboration' looking to probe the spin structure of the proton and the neutron using high energy muon beams (April 1992, page 21). Both these experiments address important physics issues. While SMC is already taking data, NA48 will not become operational until 1995, but should run then for more than three years. Elsewhere at the SPS, ongoing studies include a programme using hyperon beams, and a study of beauty particles (WA92) which would be hampered once the new neutrino programme starts. The spectroscopy of particles containing light quarks, although far from having solved all outstanding questions, is slowly coming to the end of its SPS career. The WA91 glueball search at the big Omega detector will continue taking data in 1994. The GAMS experiment took its final CERN data last year. One of the long-standing examples of CERN-Russian collaboration, GAMS earned its acronym from the Russian abbreviation for its characteristic large lead-glass arrays. GAMS experiments have run both at CERN and at Serpukhov's Institute for High Energy Physics near Moscow

  3. Development of a small, nanosecond timing fast neutron spectrometer

    International Nuclear Information System (INIS)

    A neutron spectrometer has been developed for use inside a fast neutron assembly. The spectrometer is small and insensitive to gamma radiation. An optical system was developed which could collect about 80 per cent of the light from an NE213 liquid scintillator and transmit it along a 450 mm quartz light guide to a high performance photomultiplier. To enable the detector to be used as a nanosecond timing spectrometer, several calibration measurements were made of the detector efficiency and response to monoenergetic neutrons

  4. Real‑time, fast neutron detection for stimulated safeguards assay

    International Nuclear Information System (INIS)

    The advent of low‑hazard organic liquid scintillation detectors and real‑time pulse‑shape discrimination (PSD) processing has suggested a variety of modalities by which fast neutrons, as opposed to neutrons moderated prior to detection, can be used directly to benefit safeguards needs. In this paper we describe a development of a fast‑neutron based safeguards assay system designed for the assessment of 235U content in fresh fuel. The system benefits from real‑time pulse‑shape discrimination processing and auto‑calibration of the detector system parameters to ensure a rapid and effective set‑up protocol. These requirements are essential in optimising the speed and limit of detection of the fast neutron technique, whilst minimising the intervention needed to perform the assay.

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

    Science.gov (United States)

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

    2016-03-01

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

  6. Studying Kinetics with Neutrons Prospects for Time-Resolved Neutron Scattering

    CERN Document Server

    Eckold, Götz; Nagler, Stephen E

    2010-01-01

    Neutrons are extremely versatile probes for investigating structure and dynamics in condensed matter. Due to their large penetration depth, they are ideal for in-situ measurements of samples situated in sophisticated and advanced environments. The advent of new high-intensity neutron sources and instruments, as well as the development of new real-time techniques, allows the tracking of transformation processes in condensed matter on a microscopic scale. The present volume provides a review of the state of the art of this new and exciting field of kinetics with neutrons

  7. 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.

  8. 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.

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

    International Nuclear Information System (INIS)

    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 6Li-enriched tiles to absorb outlier neutrons. In this paper, the design and performance of the new TPC are reported in detail

  10. Neutron Capture Reactions on Fe and Ni Isotopes for the Astrophysical s-process

    International Nuclear Information System (INIS)

    Neutron capture cross sections in the keV neutron energy region are the key nuclear physics input to study the astrophysical slow neutron capture process. In the past years, a series of neutron capture cross section measurements has been performed at the neutron time-of-flight facility nTOF at CERN focussing on the Fe/Ni mass region. Recent results and future developments in the neutron time-of-flight technique are discussed

  11. Neutron Time Projection Chamber for Nuclear Security and Verification Applications

    International Nuclear Information System (INIS)

    Detection of fast neutrons produced by fission is a powerful method for discovering, verifying the presence, or monitoring significant quantities of special nuclear material (SNM) at up to moderate distances. Fast neutrons are relatively rare in the natural background and can be very penetrating, even in situations when the energetic gamma-rays are well shielded. Fast neutrons point in the direction of their source and can thus be considered for use in imaging, a feature desirable for rapid, high-signal-to-noise detection of concealed SNM and for nuclear verification. We describe the development and performance of a prototype neutron time projection chamber (nTPC) and its use for directional neutron detection and high-resolution neutron imaging. The nTPC is based on ∼0.025 m3 of a hydrogen-methane mixture and utilizes a readout system with low channel count and is optimized for low event rates. We experimentally demonstrate robust operation, reliable particle identification, event-by-event directional reconstruction over the entire 4π solid angle, and insensitivity to gamma-rays. High-efficiency and high-resolution modes of operation based on single and double neutron scatters, respectively, have also been demonstrated.

  12. Neutron Capture Measurements on Minor Actinides at the n-TOF Facility at CERN: Past, Present and Future

    International Nuclear Information System (INIS)

    The successful development of advanced nuclear systems for sustainable energy production and nuclear waste management depends on high quality nuclear data libraries. Recent sensitivity studies and reports have identified the need for substantially improving the accuracy of neutron cross-section data for minor actinides. The n-TOF collaboration has initiated an ambitious experimental program for the measurement of neutron capture cross sections of minor actinides. Two experimental setups have been constructed for this purpose: a Total Absorption Calorimeter (TAC) for measuring neutron capture cross-sections of low-mass and/or radioactive samples and a set of two low neutron sensitivity C6D6 detectors for the less radioactive materials. (authors)

  13. Neutron Capture Measuremetns on Minor Actinides at the n_TOF Facility at CERN: Past, Present and Future

    CERN Document Server

    Cano-Ott, D; Eleftheriadis, C; Leeb, H; Calvino, F; Herrera-Martinez, A; Savvidis, I; Vlachoudis, V; Haas, B; Abbondanno, U; Vannini, G; Oshima, M; Gramegna, F; Wiescher, M; Pigni, M T; Wiendler, H; Mengoni, A; Quesada, J; Becvar, F; Rosetti, M; Cennini, P; Mosconi, M; Duran, I; Rauscher, T; Ketlerov, V; Couture, A; Capote, R; Sarchiapone, L; Vlastou, R; Domingo-Pardo, C; Pavlopoulos, P; Karamanis, D; Krticka, M; Griesmayer, E; Jericha, E; Ferrari, A; Martinez, T; Oberhummer, H; Karadimos, D; Plompen, A; Mendoza, E; Terlizzi, R; Cortes, G; Cox, J; Voss, F; Pretel, C; Colonna, N; Berthoumieux, E; Dolfini, R; Vaz, P; Heil, M; Lopes, I; Lampoudis, C; Walter, S; Calviani, M; Gonzalez-Romero, E; Stephan, C; Tain, J L; Belloni, F; Igashira, M; Papachristodoulou, C; Aerts, G; Tavora, L; Milazzo, P M; Rudolf, G; Andrzejewski, J; Villamarin, D; Ferreira-Marques, R; Meaze, M H; O'Brien, S; Gunsing, F; Reifarth, R; Perrot, L; Lindote, A; Neves, F; Poch, A; Konovalov, V; Kerveno, M; Marques, L; Rubbia, C; Koehler, P; Dahlfors, M; Wisshak, K; Fujii, K; De Albornoz, A C; Salgado, J; Dridi, W; Ventura, A; Andriamonje, S; Dillman, I; Assimakopoulos, P; Ferrant, L; Lozano, M; Patronis, N; Chiaveri, E; Guerrero, C; Kadi, Y; Vicente, M C; Praena, J; Baumann, P; Moreau, C; Kappeler, F; Rullhusen, P; Furman, W; David, S; Marrone, S; Paradela, C; Audouin, L; Tassan-Got, L; Alvarez-Velarde, F; Massimi, C; Mastinu, P; Isaev, S; Pancin, J; Papadopoulos, C; Tagliente, G; Alvarez, H; Haight, R; Goverdovski, A; Chepel, V; Plag, R; Kossionides, E; Badurek, G; Marganiec, J; Lukic, S; Frais-Koelbl, H; Pavlik, A; Goncalves, I

    2011-01-01

    The successful development of advanced nuclear systems for sustainable energy production and nuclear waste management depends on high quality nuclear data libraries. Recent sensitivity studies and reports {[}1-3] have identified the need for substantially improving the accuracy of neutron cross-section data for minor actinides. The n\\_TOF collaboration has initiated an ambitious experimental program for the measurement of neutron capture cross sections of minor actinides. Two experimental setups have been constructed for this purpose: a Total Absorption Calorimeter (TAC) {[}4] for measuring neutron capture cross-sections of low-mass and/or radioactive samples and a set of two low neutron sensitivity C(6)D(6) detectors for the less radioactive materials.

  14. Neutron capture measuremetns on minor actinides at the n_TOF facility at CERN: past, present and future

    OpenAIRE

    Cano Ott, Daniel; Colonna, Nicola; Tagliente, G; Belloni, Fabio; Calviño Tavares, Francisco; Cortés Rossell, Guillem Pere; Poch Parés, Agustí; Pretel Sánchez, Carme

    2011-01-01

    The successful development of advanced nuclear systems for sustainable energy production and nuclear waste management depends on high quality nuclear data libraries. Recent sensitivity stud- ies and reports [1-3] have identi ed the need for substantially improving the accuracy of neutron cross-section data for minor actinides. The n TOF collaboration has initiated an ambitious exper- imental program for the measurement of neutron capture cross sections of minor actinides. Two e...

  15. Tests of time reversal in neutron-nucleus scattering

    International Nuclear Information System (INIS)

    Experiments to test time-reversal invariance are discussed. The experiments are based on observables constructed from the momentum and spin vectors of epithermal neutrons and from the spin of an aligned or polarized target. It is shown that the proposed tests are detailed balance tests of time-reversal invariance. The status of the experiments is briefly reviewed. 14 refs., 5 figs

  16. CERN Choir

    CERN Multimedia

    Staff Association

    2015-01-01

      Do you like singing? The CERN Choir is looking for basses and tenors Join us! Programme Spring Session 2015: Donizetti: Misere & Missa di Gloria e Credo Bellini: Salve Regina Bruckner: Requiem in D minor Next concert: Sunday 31 May 2015 at 17:00 Musicales de Comesières (GE) Rehearsals at CERN Main Auditorium, building 500 On Wednesdays from 20.00 to 22:00 Membership fee: January to June 150 CHF September to December: 100CHF Contact: Baudouin.bleus@cern.ch Facebook/Choeur-du-CERN

  17. Timing and position response of a block detector for fast neutron time-of-flight imaging

    International Nuclear Information System (INIS)

    Our research effort seeks to improve the spatial and timing performance of a block detector made of a pixilated plastic scintillator (EJ-200), first demonstrated as part of Oak Ridge National Laboratory's Advanced Portable Neutron Imaging System. Improvement of the position and time response is necessary to achieve better resolution and contrast in the images of shielded special nuclear material. Time-of-flight is used to differentiate between gamma and different sources of neutrons (e.g., transmission and fission neutrons). Factors limiting the timing and position performance of the neutron detector have been revealed through simulations and measurements. Simulations have suggested that the degradation in the ability to resolve pixels in the neutron detector is due to those interactions occurring near the light guide. The energy deposition within the neutron detector is shown to affect position performance and imaging efficiency. This examination details how energy cuts improve the position performance and degrade the imaging efficiency. Measurements have shown the neutron detector to have a timing resolution of σ=238 ps. The majority of this timing uncertainty is from the depth-of-interaction (DOI) of the neutron which is confirmed by simulations and analytical calculations

  18. The 1956 CERN Symposium

    CERN Document Server

    Jarlskog, Cecilia

    2014-01-01

    CERN, currently the largest organization in the world for particle physics, was founded in 1954. Originally located in Meyrin, at the outskirts of the city of Geneva in Switzerland, it has with time extended into neighboring France. The Theoretical Study Division of CERN, however, was created already in 1952, i.e., before the official inauguration of CERN. It was situated in Copenhagen. Christian Møller [1] was appointed (part-time) as the Director and there were two full time senior staff members, Gunnar Källén and Ben R. Mottelson. While constructing buildings and accelerators were in progress, an international conference was organized by CERN in the city of Geneva. This “CERN Symposium on High Energy Accelerators and Pion Physics”, 11–23 June 1956, attracted about 250 participants from outside CERN, among them at least 18 Nobel Laureates or future Laureates. Unfortunately, the participants from CERN are not listed in the Proceedings [2]. The conference focused on measuring devices such as bubbl...

  19. Time-correlated neutron analysis of a multiplying HEU source

    Energy Technology Data Exchange (ETDEWEB)

    Miller, E.C., E-mail: Eric.Miller@jhuapl.edu [Johns Hopkins University Applied Physics Laboratory, Laurel, MD (United States); Kalter, J.M.; Lavelle, C.M. [Johns Hopkins University Applied Physics Laboratory, Laurel, MD (United States); Watson, S.M.; Kinlaw, M.T.; Chichester, D.L. [Idaho National Laboratory, Idaho Falls, ID (United States); Noonan, W.A. [Johns Hopkins University Applied Physics Laboratory, Laurel, MD (United States)

    2015-06-01

    The ability to quickly identify and characterize special nuclear material remains a national security challenge. In counter-proliferation applications, identifying the neutron multiplication of a sample can be a good indication of the level of threat. Currently neutron multiplicity measurements are performed with moderated {sup 3}He proportional counters. These systems rely on the detection of thermalized neutrons, a process which obscures both energy and time information from the source. Fast neutron detectors, such as liquid scintillators, have the ability to detect events on nanosecond time scales, providing more information on the temporal structure of the arriving signal, and provide an alternative method for extracting information from the source. To explore this possibility, a series of measurements were performed on the Idaho National Laboratory's MARVEL assembly, a configurable HEU source. The source assembly was measured in a variety of different HEU configurations and with different reflectors, covering a range of neutron multiplications from 2 to 8. The data was collected with liquid scintillator detectors and digitized for offline analysis. A gap based approach for identifying the bursts of detected neutrons associated with the same fission chain was used. Using this approach, we are able to study various statistical properties of individual fission chains. One of these properties is the distribution of neutron arrival times within a given burst. We have observed two interesting empirical trends. First, this distribution exhibits a weak, but definite, dependence on source multiplication. Second, there are distinctive differences in the distribution depending on the presence and type of reflector. Both of these phenomena might prove to be useful when assessing an unknown source. The physical origins of these phenomena can be illuminated with help of MCNPX-PoliMi simulations.

  20. Time-correlated neutron analysis of a multiplying HEU source

    International Nuclear Information System (INIS)

    The ability to quickly identify and characterize special nuclear material remains a national security challenge. In counter-proliferation applications, identifying the neutron multiplication of a sample can be a good indication of the level of threat. Currently neutron multiplicity measurements are performed with moderated 3He proportional counters. These systems rely on the detection of thermalized neutrons, a process which obscures both energy and time information from the source. Fast neutron detectors, such as liquid scintillators, have the ability to detect events on nanosecond time scales, providing more information on the temporal structure of the arriving signal, and provide an alternative method for extracting information from the source. To explore this possibility, a series of measurements were performed on the Idaho National Laboratory's MARVEL assembly, a configurable HEU source. The source assembly was measured in a variety of different HEU configurations and with different reflectors, covering a range of neutron multiplications from 2 to 8. The data was collected with liquid scintillator detectors and digitized for offline analysis. A gap based approach for identifying the bursts of detected neutrons associated with the same fission chain was used. Using this approach, we are able to study various statistical properties of individual fission chains. One of these properties is the distribution of neutron arrival times within a given burst. We have observed two interesting empirical trends. First, this distribution exhibits a weak, but definite, dependence on source multiplication. Second, there are distinctive differences in the distribution depending on the presence and type of reflector. Both of these phenomena might prove to be useful when assessing an unknown source. The physical origins of these phenomena can be illuminated with help of MCNPX-PoliMi simulations

  1. Searching for time reversal invariance violation in polarized neutron decay

    International Nuclear Information System (INIS)

    Time reversal invariance violation is tightly constrained in the Standard Model, and the existence of a T-violating effect above the predicted level would be an indication of new physics. A sensitive probe of this symmetry in the weak interaction is the measurement of the D-coefficient in neutron decay. This parameter characterizes the triple-correlation of neutron spin, electron momentum, and neutrino (or proton) momentum, which changes sign under time reversal. The emiT experiment, now on line, attempts to improve the measurement of D, whose current average is 0.3±1.5x10-3. copyright 1997 American Institute of Physics

  2. Searching for time reversal invariance violation in polarized neutron decay

    International Nuclear Information System (INIS)

    Time reversal invariance violation is tightly constrained in the Standard Model, and the existence of a T-violating effect above the predicted level would be an indication of new physics. A sensitive probe of this symmetry in the weak interaction is the measurement of the D-coefficient in neutron decay. This parameter characterizes the triple-correlation of neutron spin, electron momentum, and neutrino (or proton) momentum, which changes sign under time reversal. The emiT experiment, now on line, attempts to improve the measurement of D, whose current average is 0.3±1.5x10-3

  3. Nuclear superfluidity and cooling time of neutron-star crust

    Energy Technology Data Exchange (ETDEWEB)

    Monrozeau, C.; Margueron, J. [Institut de Physique Nucleaire, Universite Paris Sud, F-91406 Orsay CEDEX (France); Sandulescu, N. [Institut de Physique Nucleaire, Universite Paris Sud, F-91406 Orsay CEDEX (France); Institute of Physics and Nuclear Engineering, RO-76900 Bucharest (Romania)

    2007-03-15

    We analyse the effect of neutron superfluidity on the cooling time of inner crust matter in neutron stars, in the case of a rapid cooling of the core. The specific heat of the inner crust, which determines the thermal response of the crust, is calculated in the framework of HFB approach at finite temperature. The calculations are performed with two paring forces chosen to simulate the pairing properties of uniform neutron matter corresponding respectively to Gogny-BCS approximation and to many-body techniques including polarisation effects. Using a simple model for the heat transport across the inner crust, it is shown that the two pairing forces give very different values for the cooling time. (authors)

  4. Neutron and x-ray emission time measurements

    International Nuclear Information System (INIS)

    Laser fusion targets can produce implosions with a delay between the peak compression (neutron emission) and the laser pulse on the order of 0.2 to 2.5 ns. We use a fast detector system to measure x-ray and D-T neutron emission times with a resolution of 100 to 200 ps. An NE111 fluor (quenched with 2% benzophenone) coupled to a microchannel plate photomultiplier tube detects the arrival of neutrons and x rays. A separate biplanar vacuum photodiode detects the arrival of unabsorbed laser light scattered from the target. These signals are mixed, then recorded on a 500 MHz transient digitizer. The discussion includes a description of the time interval system, experimental data, data analysis techniques, and system calibration

  5. Nuclear superfluidity and cooling time of neutron-star crust

    International Nuclear Information System (INIS)

    We analyse the effect of neutron superfluidity on the cooling time of inner crust matter in neutron stars, in the case of a rapid cooling of the core. The specific heat of the inner crust, which determines the thermal response of the crust, is calculated in the framework of HFB approach at finite temperature. The calculations are performed with two paring forces chosen to simulate the pairing properties of uniform neutron matter corresponding respectively to Gogny-BCS approximation and to many-body techniques including polarisation effects. Using a simple model for the heat transport across the inner crust, it is shown that the two pairing forces give very different values for the cooling time. (authors)

  6. Courrier CERN

    CERN Multimedia

    2015-01-01

    Example of the cover page of the French version of the CERN Courier; Courrier CERN from January 1962. The journal was published both in English and French up to volume 45, no. 5, June 2005. Since then there is a single-language edition where articles are published either in French or English with an abstract in the other language.

  7. CERN & Society

    CERN Multimedia

    2016-01-01

    Non Member State Summer Students 2015 are interviewed about their decision to study STEM subjects, to apply for CERN NMSSS programme, their experience onsite @CERN and takeaways, their future goals and aspirations, offering also advice to fellow students.The Non Member State Summer Student Programme stands for a unique opportunity for students from all over the world to spend their summer at CERN in Geneva, getting involved in some of the world’s biggest experiments. For 8 weeks, summer students gather on-site at CERN and join in the day-to-day work of research. The Programme targets advanced undergraduate and beginning graduate students of physics, computing and engineering, particularly from developing countries. Participating students receive scientific training, attend lectures and work on laboratory-based projects alongside with CERN experts and fellow students.

  8. A real time scintillating fiber Time of Flight spectrometer for LINAC photoproduced neutrons

    Science.gov (United States)

    Maspero, M.; Berra, A.; Conti, V.; Giannini, G.; Ostinelli, A.; Prest, M.; Vallazza, E.

    2015-03-01

    The use of high-energy (> 8 MeV) LINear ACcelerators (LINACs) for medical cancer treatments causes the photoproduction of secondary neutrons, whose unwanted dose to the patient has to be calculated. The characterization of the neutron spectra is necessary to allow the dosimetric evaluation of the neutron beam contamination. The neutron spectrum in a hospital environment is usually measured with integrating detectors such as bubble dosimeters, Thermo Luminescent Dosimeters (TLDs) or Bonner Spheres, which integrate the information over a time interval and an energy one. This paper presents the development of a neutron spectrometer based on the Time of Flight (ToF) technique in order to perform a real time characterization of the neutron contamination. The detector measures the neutron spectrum exploiting the fact that the LINAC beams are pulsed and arranged in bunches with a rate of 100-300 Hz depending on the beam type and energy. The detector consists of boron loaded scintillating fibers readout by a MultiAnode PhotoMultiplier Tube (MAPMT). A detailed description of the detector and the acquisition system together with the results in terms of ToF spectra and number of neutrons with a Varian Clinac iX are presented.

  9. Development and testing of neutron pulse time stamping data acquisition system for neutron noise experiment

    International Nuclear Information System (INIS)

    Statistical correlation techniques find applications in the analysis of zero power reactor noise and in passive neutron assay (PNA). A large number of apparently different techniques have been in use in these application areas and traditionally the electronics modules used for data acquisition and analysis is specific to the method used. In this paper we describe a data acquisition scheme developed by us, which is independent of the specific analysis method and can therefore be used for all of them. This is a neutron time stamping data acquisition system based on a timer card and an interface software to acquire and store the data in the required format. The system has been successfully tested with two statistically different types of neutron sources, namely a random Poisson source (Pu–Be) and a correlated source (a nuclear reactor)

  10. CERN expositions permanentes

    CERN Document Server

    2016-01-01

    Explore by yourself the issues CERN's physicists are trying to solve: given that the entire universe is made of particles, where do they come from? Why do they behave in the way they do? Discover the massive apparatus used by physicists at CERN, like the LHC, and see how each part works. And if you have more time on site, follow the LHC circuit at ground level to understand in situ this giant machine. Enter our exhibitions. Welcome!

  11. CERN permanent exhibitions

    CERN Multimedia

    2016-01-01

    Explore by yourself the issues CERN's physicists are trying to solve: given that the entire universe is made of particles, where do they come from? Why do they behave in the way they do? Discover the massive apparatus used by physicists at CERN, like the LHC, and see how each part works. And if you have more time on site, follow the LHC circuit at ground level to understand in situ this giant machine. Enter our exhibitions. Welcome!

  12. Big research in new dimensions. Thinkers of our time about the actual elementary-particle physics at CERN; Grossforschung in neuen Dimensionen. Denker unserer Zeit ueber die aktuelle Elementarteilchenphysik am CERN

    Energy Technology Data Exchange (ETDEWEB)

    Kommer, Christoph (ed.) [Heidelberg Univ. (Germany); DKFZ, Heidelberg (Germany); Satz, Helmut [Bielefeld Univ. (Germany). Fakultaet fuer Physik; Blanchard, Philippe [Bielefeld Univ. (Germany). Abt. Theoretische Physik

    2016-07-01

    The following topics are dealt with: Research from the highest energies to the smallest particles at CERN, the laborious way to the Large Hadronic Collider, CERN as accelerator of techniques, culture, and society, a philosophical and sociological perspective of questions concerning CERN, quark matter research at CERN, the FAIR facility for antiproton and ion research. (HSI)

  13. Chaotic Scattering and Escape Times of Marginally Trapped Ultracold Neutrons

    Science.gov (United States)

    Coakley, K. J.; Doyle, J. M.; Dzhosyuk, S. N.; Yang, L.; Huffman, P. R.

    2005-01-01

    We compute classical trajectories of Ultracold neutrons (UCNs) in a superconducting Ioffe-type magnetic trap using a symplectic integration method. We find that the computed escape time for a particular set of initial conditions (momentum and position) does not generally stabilize as the time step parameter is reduced unless the escape time is short (less than approximately 10 s). For energy intervals where more than half of the escape times computed for UCN realizations are numerically well determined, we predict the median escape time as a function of the midpoint of the interval.

  14. Neutron Slowing-Down Time and Thermalization Time Constant in Graphite

    International Nuclear Information System (INIS)

    The classical mechanics are able to describe the energy decrease of fast neutrons in their collision with moderator nuclei. However, when those neutrons are slowed down into the energy range of chemical binding of the moderator, such a simple model in which the collision of neutrons is treated as that of billiard balls is not valid; therefore more extended models have been suggested, including phonon exchange between the neutron and moderator lattice. In order to prove their validity, a series of pulsed neutron experiments was performed to investigate neutron moderation and thermalization in a graphite pile. The graphite pile is of nuclear reactor grade with density 1.54 and is 240 cm in height and 120 cm in a side of its hexagonal cross-section. Bursts of neutrons of width 1 microsecond were generated at the centre of the pile. The slowing-down and diffusing neutrons were detected by bare and energy-selective, filter-covered BF3 counters and analysed with a 256-channel time analyser. By interpreting that the increment of the difference of the events between the bare and the filter covered counter is due to the contribution made by that fraction of the neutrons slowing down at the time of measurement below the cut-off energy of the filter, slowing-down times in graphite were determined. As the results of the experiment, slowing-down times below 1.46, 0.61, 0.50, 0.41 and 0.21 eV were determined as 23, 36.9, 41.6, 45.8 and 87.5 μs respectively. The thermalization time constant in graphite was also determined as (296 ± 50)μs by using the silver filter transmission method. It is concluded that the crystal model is capable of describing most satisfactorily the slowing-down and thermalization phenomena in graphite. (author)

  15. Understanding inelastically scattered neutrons from water on a time-of-flight small-angle neutron scattering (SANS) instrument

    CERN Document Server

    Doa, Changwoo; Stanley, Christopher; Gallmeier, Franz X; Doucet, Mathieu; Smith, Gregory S

    2013-01-01

    It is generally assumed by most of the small-angle neutron scattering (SANS) user community that a neutrons energy is unchanged during SANS measurements. Here, the scattering from water, specifically light water, was measured on the EQ-SANS instrument, a time-of-flight SANS instrument located at the Spallation Neutron Source of Oak Ridge National Laboratory. A significant inelastic process was observed in the TOF spectra of neutrons scattered from water. Analysis of the TOF spectra from the sample showed that the scattered neutrons have energies consistent with room-temperature thermal energies (~20 meV) regardless of the incident neutron energy. With the aid of Monte Carlo particle transport simulations, we conclude that the thermalization process within the sample results in faster neutrons that arrive at the detector earlier than expected based on the incident neutron energies. This thermalization process impacts the measured SANS intensities in a manner that will ultimately be sample- and temperature-depe...

  16. A time lens for high resolution neutron time of flight spectrometers

    OpenAIRE

    K. Baumann; Gaehler, R.; Grigoriev, P. D.; Kats, E.I.

    2005-01-01

    We examine in analytic and numeric ways the imaging effects of temporal neutron lenses created by traveling magnetic fields. For fields of parabolic shape we derive the imaging equations, investigate the time-magnification, the evolution of the phase space element, the gain factor and the effect of finite beam size. The main aberration effects are calculated numerically. The system is technologically feasible and should convert neutron time of flight instruments from pinhole- to imaging confi...

  17. Time reversal invariance - a test in free neutron decay

    International Nuclear Information System (INIS)

    Time reversal invariance violation plays only a small role in the Standard Model, and the existence of a T-violating effect above the predicted level would be an indication of new physics. A sensitive probe of this symmetry in the weak interaction is the measurement of the T-violating ''D''-correlation in the decay of free neutrons. The triple-correlation Dσn·pe x pv involves three kinematic variables, the neutron spin, electron momentum, and neutrino (or proton) momentum, and changes sign under time reversal. This experiment detects the decay products of a polarized cold neutron beam with an octagonal array of scintillation and solid-state detectors. Data from first run at NIST's Cold Neutron Research Facility give a D-coefficient of -0.1 ± 1.3(stat.) ± 0.7(syst) x 10-3. This measurement has the greatest bearing on extensions to the Standard model that incorporate leptoquarks, although exotic fermion and lift-right symmetric models also allow a D as large as the present limit

  18. Time reversal invariance - a test in free neutron decay

    Energy Technology Data Exchange (ETDEWEB)

    Lising, Laura J.

    1999-05-18

    Time reversal invariance violation plays only a small role in the Standard Model, and the existence of a T-violating effect above the predicted level would be an indication of new physics. A sensitive probe of this symmetry in the weak interaction is the measurement of the T-violating ''D''-correlation in the decay of free neutrons. The triple-correlation D{sigma}{sub n}{center_dot}p{sub e} x p{sub v} involves three kinematic variables, the neutron spin, electron momentu, and neutrino (or proton) momentum, and changes sign under time reversal. This experiment detects the decay products of a polarized cold neutron beam with an octagonal array of scintillation and solid-state detectors. Data from first run at NIST's Cold Neutron Research Facility give a D-coefficient of -0.1 {+-} 1.3(stat.) {+-} 0.7(syst) x 10{sup -3}. This measurement has the greatest bearing on extensions to the Standard model that incorporate leptoquarks, although exotic fermion and lift-right symmetric models also allow a D as large as the present limit.

  19. Time reversal invariance - a test in free neutron decay

    CERN Document Server

    Lising, L J

    1999-01-01

    Time reversal invariance violation plays only a small role in the Standard Model, and the existence of a T-violating effect above the predicted level would be an indication of new physics. A sensitive probe of this symmetry in the weak interaction is the measurement of the T-violating ''D''-correlation in the decay of free neutrons. The triple-correlation D sigma sub n centre dot p sub e x p sub v involves three kinematic variables, the neutron spin, electron momentum, and neutrino (or proton) momentum, and changes sign under time reversal. This experiment detects the decay products of a polarized cold neutron beam with an octagonal array of scintillation and solid-state detectors. Data from first run at NIST's Cold Neutron Research Facility give a D-coefficient of -0.1 +- 1.3(stat.) +- 0.7(syst) x 10 sup - sup 3. This measurement has the greatest bearing on extensions to the Standard model that incorporate leptoquarks, although exotic fermion and lift-right symmetric models also allow a D as large as the pre...

  20. CERN 1981-8

    International Nuclear Information System (INIS)

    At the CERN Council Meeting in December, the Director General traditionally gives an end-of-year review. This time the presentation took on added significance as it marked the end of the eight-year mandate of Herwig Schopper, who handed over on 1 January to Carlo Rubbia. Looking back over those eight years, Schopper pointed out several major trends. The dramatic growth in CERN 'users' (the scientists coming to the Laboratory to do their research) has led to CERN's research programme becoming really worldwide. The attrition of having to operate an expanding Laboratory under a constant budget has produced in its wake a healthy increase in the efficiency of CERN's big machines and experimental facilities

  1. MINARET: Towards a time-dependent neutron transport parallel solver

    International Nuclear Information System (INIS)

    We present the newly developed time-dependent 3D multigroup discrete ordinates neutron transport solver that has recently been implemented in the MINARET code. The solver is the support for a study about computing acceleration techniques that involve parallel architectures. In this work, we will focus on the parallelization of two of the variables involved in our equation: the angular directions and the time. This last variable has been parallelized by a (time) domain decomposition method called the para-real in time algorithm. (authors)

  2. Bubble masks for time-encoded imaging of fast neutrons.

    Energy Technology Data Exchange (ETDEWEB)

    Brubaker, Erik; Brennan, James S.; Marleau, Peter; Nowack, Aaron B.; Steele, John; Sweany, Melinda; Throckmorton, Daniel J.

    2013-09-01

    Time-encoded imaging is an approach to directional radiation detection that is being developed at SNL with a focus on fast neutron directional detection. In this technique, a time modulation of a detected neutron signal is induced-typically, a moving mask that attenuates neutrons with a time structure that depends on the source position. An important challenge in time-encoded imaging is to develop high-resolution two-dimensional imaging capabilities; building a mechanically moving high-resolution mask presents challenges both theoretical and technical. We have investigated an alternative to mechanical masks that replaces the solid mask with a liquid such as mineral oil. Instead of fixed blocks of solid material that move in pre-defined patterns, the oil is contained in tubing structures, and carefully introduced air gaps-bubbles-propagate through the tubing, generating moving patterns of oil mask elements and air apertures. Compared to current moving-mask techniques, the bubble mask is simple, since mechanical motion is replaced by gravity-driven bubble propagation; it is flexible, since arbitrary bubble patterns can be generated by a software-controlled valve actuator; and it is potentially high performance, since the tubing and bubble size can be tuned for high-resolution imaging requirements. We have built and tested various single-tube mask elements, and will present results on bubble introduction and propagation as a function of tubing size and cross-sectional shape; real-time bubble position tracking; neutron source imaging tests; and reconstruction techniques demonstrated on simple test data as well as a simulated full detector system.

  3. Temperature dependent formation-time approach for $\\Upsilon$ suppression at energies available at the CERN Large Hadraon Collider

    CERN Document Server

    Ganesh, S

    2015-01-01

    We present here a comprehensive model to describe the bottomonium suppression data obtained from the CERN Large Hadron Collider (LHC) at center-of-mass energy of $\\sqrt{s_{NN}}=2.76$ TeV. We employ a quasiparticle model (QPM) equation of state for the quark-gluon plasma (QGP) expanding under Bjorken's scaling law. The current model includes the modification of the formation time based on the temperature of the QGP, color screening during bottomonium production, gluon induced dissociation and collisional damping due to the imaginary part of the potential between the $b\\bar b$ pair. We propose a method for determining the temperature-dependent formation time of bottomonia using the solution of the time-independent Schr\\"{o}dinger equation and compare it with another approach based on time-dependent Schr\\"{o}dinger wave equation simulation. We find that these two independent methods based on different axioms give similar results for the formation time. Cold nuclear matter effects and feed-down from higher resona...

  4. Measurement of the $^{233}$U neutron capture cross section at the n_TOF facility at CERN

    CERN Document Server

    Carrapiço, Carlos; Berthoumieux, Eric; Gonçalves, Isabel; Gunsing, Frank

    2012-12-12

    The Thorium-Uranium (Th-U) fuel cycle has been envisaged as an alternative to the Uranium-Plutonium (U-Pu) fuel cycle for electricity generation using nuclear power reactors. Indeed, thorium can be used as a nuclear fuel, and several studies and R&D programs seem to provide evidence on the sustainability of the Th-U fuel cycle, due to (i) the natural abundance of Thorium, (ii) the improved proliferation resistance offered by the Th-U fuel cycle relative to the U-Pu fuel cycle, (iii) the better neutronics performance of the Th-U fuel cycle throughout the whole neutron energy range compared to the U-Pu fuel cycle, (iv) the lower radiotoxicity of the generated spent fuel in reactors with Th-U fuel cycle and, consequently (v) better economics and public acceptance of the reactors operated using the Th-U fuel cycle compared to those using the U-Pu fuel cycle (prior to the Generation IV nuclear reactors). In a nuclear reactor operated using the Th-U fuel cycle, $^{233}$U is a key nuclide governing the neutr...

  5. Neutron Time of Flight Spectrometer for Velocity Selector Calibration

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Small angle neutron spectrometer on China Advanced Research Reactor (CARR) is located at neutron guide hall and is installed on the end of cold neutron guide. Velocity selector which can purify white light neutron beam into monochromatic neutron beam with wavelength

  6. CERN openlab Open Day

    CERN Multimedia

    Andrew Purcell

    2015-01-01

    CERN openlab is the unique public-private partnership between CERN and leading companies in the field of information and communication technology. The programme is now entering an exciting new phase and is expanding to include other public research organisations for the first time. A special event will be held at CERN to mark this occasion.   CERN openlab was created in 2001 and is now entering its fifth three-year phase (2015-2017). Its mission is to accelerate the development of cutting-edge solutions to be used by the scientific community to control the operations of complex machines and to analyse the vast amounts of data produced by physics experiments. During Run 2 of the LHC, it is expected that the CERN Data Centre will store more than 30 petabytes of data per year from the LHC experiments, which is equivalent to about 1.2 million Blu-ray discs, or 250 years of HD video. Testing in this demanding environment provides the companies collaborating in CERN openlab with valuable feedback o...

  7. CERN Pensioners Association

    CERN Multimedia

    The GAC Committee

    2004-01-01

    Open Day To all CERN retired staff As part of the celebrations organised for the 50th anniversary of CERN, an Open Day will be held on Saturday 16 October 2004. Anyone willing to act as a guide, either to help and inform visitors at the reception points or to guide groups of visitors, sharing your knowledge with them, is invited to fill in the attached form. A preparatory meeting will be arranged for those who left CERN some time ago and whose knowledge of the site may no longer be quite up-to-date. The Open Day organisers need your help, which will be very much appreciated. We hope that many pensioners will participate. People with internet access may enrol directly without coming to CERN, http://www.cern.ch/CERN50/openday The GAC Committee OPEN DAY : CALL FOR VOLUNTEERS 16th October 2004 So now you are excited about the Open Day, how can you participate? As you can imagine, for such a large number of activities, we need many volunteers. Please return the following form to Elena Battis...

  8. Eberhard Widmann (Stefan Meyer Institute, Vienna) and Silke Federmann (Ph.D. Student from Vienna in the CERN-Austrian Ph.D. program) together with a microwave cavity developed by Silke at CERN. The cavity will be used for the first time to look for spin-flip transitions of antihydrogen atoms later this year.

    CERN Multimedia

    Maximilien Brice

    2011-01-01

    Eberhard Widmann (Stefan Meyer Institute, Vienna) and Silke Federmann (Ph.D. Student from Vienna in the CERN-Austrian Ph.D. program) together with a microwave cavity developed by Silke at CERN. The cavity will be used for the first time to look for spin-flip transitions of antihydrogen atoms later this year.

  9. New State of Matter created at CERN

    CERN Multimedia

    CERN Press Office. Geneva

    2000-01-01

    New State of Matter created at CERN At a special seminar on 10 February, spokespersons from the experiments on CERN 's Heavy Ion programme presented compelling evidence for the existence of a new state of matter in which quarks, instead of being bound up into more complex particles such as protons and neutrons, are liberated to roam freely.

  10. Measurement of linear energy transfer distribution at CERN-EU high- energy reference field facility with real-time radiation monitoring device III and its comparison with dosimetric telescope

    CERN Document Server

    Doke, T; Hara, K; Hayashi, T; Kikuchi, J; Suzuki, S; Terasawa, K

    2004-01-01

    The distributions of linear energy transfer for LET (LET/sub water/) in front of the 80-cm-thick concrete side shield at the CERN-EU high- energy reference field (CERF) facility were measured with a Si detector telescope named real-time radiation monitoring device-III (RRMD-III) covered with and without a 1 cm-thick acrylic plate. In these measurements, a difference of about 20% in the absorbed dose between the two LET/sub water/ distributions was observed as a result of protons, deuterons and tritons recoiled by neutrons. The LET/sub water/ distribution obtained using RRMD-III without the 1-cm-thick acrylic plate is compared with lineal energy distributions obtained using the dosimetric telescope (DOSTEL) detector under the same conditions. These dose equivalents are also compared with that obtained using HANDI TEPC which is used as the standard at the CERF facility. (26 refs).

  11. An OpenMP Parallelisation of Real-time Processing of CERN LHC Beam Position Monitor Data

    CERN Document Server

    Renshall, H

    2012-01-01

    SUSSIX is a FORTRAN program for the post processing of turn-by-turn Beam Position Monitor (BPM) data, which computes the frequency, amplitude, and phase of tunes and resonant lines to a high degree of precision. For analysis of LHC BPM data a specific version run through a C steering code has been implemented in the CERN Control Centre to run on a server under the Linux operating system but became a real time computational bottleneck preventing truly online study of the BPM data. Timing studies showed that the independent processing of each BPMs data was a candidate for parallelization and the Open Multiprocessing (OpenMP) package with its simple insertion of compiler directives was tried. It proved to be easy to learn and use, problem free and efficient in this case reaching a factor of ten reductions in real-time over twelve cores on a dedicated server. This paper reviews the problem, shows the critical code fragments with their OpenMP directives and the results obtained.

  12. Resolution kernels in time-of-flight neutron reflectometers

    International Nuclear Information System (INIS)

    Instrumental resolution functions must be taken into account when analysing Neutron Reflectometry data. These resolution functions are obtained by convolving the resolution kernels for the angular and wavelength components. In the past most data reduction and analysis processes have assumed that the overall resolution kernel is Gaussian in shape. Whilst this is the case for monochromatic reflectometers this is not true for those Time-Of-Flight (TOF) Neutron Reflectometers, such as Platypus which possess rectangular wavelength resolution distributions (a consequence of the disc chopper systems used). In such situations the resolution function is typically trapezoidal in shape. Here we detail how a more detailed description of the instrumental resolution function is calculated2. In addition, we outline the situations where the differences between the detailed and approximate resolution kernels become apparent, with the main effects being observed when the width of the resolution kernel is similar to the width of the features in the reflectivity curve.

  13. Real-time dosimetry for boron-neutron capture therapy

    International Nuclear Information System (INIS)

    Epithermal/thermal boron neutron-capture therapy (BNCT) is promising treatment method for malignant tumors. Because the doses and dose rates for medical therapeutic radiation are very close to the normal tissue tolerance, small errors in radiation delivery can result in harmful overdoses. A substantial need exists for a device that will monitor, in real time, the radiation dose being delivered to a patient. Pacific Northwest Laboratory (PNL) has developed a scintillating glass optical fiber that is sensitive to thermal neutrons. The small size of the fibers offers the possibility of in vivo dose monitoring at several points within the radiation field. The count rate of such detectors can approach 10 MHz because the lifetime of the cerium activator is fast. Fluxes typical of those in BNCT (i.e., 109 n/cm2/sec) may be measured because of this potentially high count rate and the small diameter of the fiber

  14. CERN openlab enters fifth phase

    CERN Multimedia

    Andrew Purcell

    2015-01-01

    CERN openlab is a unique public-private partnership between CERN and leading ICT companies. At the start of this year, openlab officially entered its fifth phase, which will run until the end of 2017. For the first time in its history, it has extended beyond the CERN community to include other major European and international research laboratories.   Founded in 2001 to develop the innovative ICT systems needed to cope with the unprecedented computing challenges of the LHC, CERN openlab unites science and industry at the cutting edge of research and innovation. In a white paper published last year, CERN openlab set out the main ICT challenges it will tackle during its fifth phase, namely data acquisition, computing platforms, data storage architectures, computer management and provisioning, networks and connectivity, and data analytics. As it enters its fifth phase, CERN openlab is expanding to include other research laboratories. "Today, research centres in other disciplines are also st...

  15. Equipment for fast neutron time-of-flight experiments

    International Nuclear Information System (INIS)

    A 3-MeV-pulsed Van de Graaff has been built for this laboratory by the High Voltage Engineering Corporation of Boston, United States of America. It is designed to give pulses of 1 ns duration at a repetition frequency of 1 MHz and a current in the pulse of 10 mA. This machine is to be used for fast neutron spectroscopy and a system of electronics for this purpose has been devised. The system is intended to record time intervals up to 1μs with a resolution of ∼3 ns. The timing cycle is started by a start pulse from the neutron detector. The stop pulse is derived from the beam, and delayed by 1μs. The start and stop pulses are fed to a time expander which expands the time interval between the pulses by a factor of ∼250. The expanded time interval is then recorded in digital form on 16-track magnetic tape. (author)

  16. Fast fall-time ion beam in neutron generators

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Q.; Kwan, J.; Regis, M.; Wu, Y.; Wilde, S.B.; Wallig, J.

    2008-08-10

    Ion beam with a fast fall time is useful in building neutron generators for the application of detecting hidden, gamma-shielded SNM using differential die-away (DDA) technique. Typically a fall time of less than 1 {micro}s can't be achieved by just turning off the power to the ion source due to the slow decay of plasma density (partly determined by the fall time of the RF power in the circuit). In this paper, we discuss the method of using an array of mini-apertures (instead of one large aperture beam) such that gating the beamlets can be done with low voltage and a small gap. This geometry minimizes the problem of voltage breakdown as well as reducing the time of flight to produce fast gating. We have designed and fabricated an array of 16 apertures (4 x 4) for a beam extraction experiment. Using a gating voltage of 1400 V and a gap distance of 1 mm, the fall time of extracted ion beam pulses is less than 1 {micro}s at various beam energies ranging between 400 eV to 800 eV. Usually merging an array of beamlets suffers the loss of beam brightness, i.e., emittance growth, but that is not an important issue for neutron source applications.

  17. Parameters Affecting Temporal Resolution of Time Resolved Integrative Optical Neutron Detector (TRION)

    OpenAIRE

    Mor, I.; Vartsky, D.; Dangendorf, V.; Bar, D.; Feldman, G.; Goldberg, M B; Tittelmeier, K.; Bromberger, B.; Brandis, M.; Weierganz, M.

    2013-01-01

    The Time-Resolved Integrative Optical Neutron (TRION) detector was developed for Fast Neutron Resonance Radiography (FNRR), a fast-neutron transmission imaging method that exploits characteristic energy-variations of the total scattering cross-section in the En = 1-10 MeV range to detect specific elements within a radiographed object. As opposed to classical event-counting time of flight (ECTOF), it integrates the detector signal during a well-defined neutron Time of Flight window correspondi...

  18. An FPGA Based Multiprocessing CPU for Beam Synchronous Timing in CERN's SPS and LHC

    CERN Document Server

    Ballester, F J; Gras, J J; Lewis, J; Savioz, J J; Serrano, J

    2003-01-01

    The Beam Synchronous Timing system (BST) will be used around the LHC and its injector, the SPS, to broadcast timing meassages and synchronize actions with the beam in different receivers. To achieve beam synchronization, the BST Master card encodes messages using the bunch clock, with a nominal value of 40.079 MHz for the LHC. These messages are produced by a set of tasks every revolution period, which is every 89 us for the LHC and every 23 us for the SPS, therefore imposing a hard real-time constraint on the system. To achieve determinism, the BST Master uses a dedicated CPU inside its main Field Programmable Gate Array (FPGA) featuring zero-delay hardware task switching and a reduced instruction set. This paper describes the BST Master card, stressing the main FPGA design, as well as the associated software, including the LynxOS driver and the tailor-made assembler.

  19. Real-time database for high resolution neutron monitor measurements

    International Nuclear Information System (INIS)

    The worldwide network of standardised neutron monitors is, after 50 years, still the state-of-the-art instrumentation to measure spectral variations of the primary cosmic ray component. These measurements are an ideal complement to space based cosmic ray measurements. Data from the approximately 50 IGY and NM64 neutron monitors is stored locally but also available through data collections sites like the World Data Center (WDC) or the IZMIRAN ftp server. The data from the WDC is in a standard format, but only hourly values are available. IZMIRAN collects the data in the best available time resolution, but the data arrives on the ftp server only hours, sometimes days, after the measurements. Also, the high time-resolution measurements of the different stations do not have a common format, a conversion routine for each station is needed before they can be used for scientific analysis. Supported by the 7th framework program of the European Commission, we are setting up a real-time database where high resolution cosmic ray measurements will be stored and accessible immediately after the measurement. Stations that do not have 1-minute resolution measurements will be upgraded to 1-minute or better resolution with an affordable standard registration system, that will submit the measurements to the database via the internet in real-time

  20. CERN choir

    CERN Multimedia

    2004-01-01

    Don't forget a special performance of Joseph Haydn's Creation, an oratorio in three parts, given by the CERN choir and the Annecy choir Pro Musica, this Sunday at 8.30 p.m. at the Grand Casino. Tickets (38 CHF) are available at Fnac Rive and Balexert.

  1. Robot adventures at CERN

    CERN Multimedia

    2015-01-01

    Imagine if the CERN robots had an end-of-year party... From retrieving data tapes to handling material safely, the robots at CERN fulfill numerous tasks. Find out more: http://cern.ch/go/VjX7 Produced by: CERN Video Productions Director: Christoph M. Madsen Copyright © 2015 CERN. Terms of use: http://copyright.web.cern.ch/

  2. Nuclear Data Experimental Program at CERN for Reactor Physics

    International Nuclear Information System (INIS)

    The neutron time-of-flight facility n-TOF, operating at CERN since 2001, features a neutron beam that covers the energy range from thermal to 1 GeV. Its most outstanding characteristics are its long flight path (185 m) and the high instantaneous intensity (0.5-12·106 neutrons/pulse depending on the collimator configuration). The ambitious program carried out in the last decade includes a large number of experiments in the fields of nuclear energy technologies, astrophysics, basic physics, detector development and medical applications. Within the field of nuclear energy technologies most measurements are focused on determining, for the first time and/or with unprecedented accuracies, the capture and fission cross sections of actinides, both at low (resolved resonance region) and high (keV-GeV) neutron energies. This paper present a summary of all the measurements carried out since 2001 at n-TOF, including some details for several of these experiments. (author)

  3. Neutron slowing-down time in finite water systems

    International Nuclear Information System (INIS)

    The influence of the size of a moderator system on the neutron slowing-down time has been investigated. The experimental part of the study was performed on six cubes of water with side lengths from 8 to 30 cm. Neutrons generated in pulses of about 1 ns width were slowed down from 14 MeV to 1.457 eV. The detection method used was based on registration of gamma radiation from the main capture resonance of indium. The most probable slowing-down times were found to be 778 +- 23 ns and 898 +- 25 ns for the smallest and for the largest cubes, respectively. The corresponding mean slowing-down times were 1205 +- 42 ns and 1311 +- 42 ns. In a separate measurement series the space dependence of the slowing-down time close to the source was studied. These experiments were supplemented by a theoretical calculation which gave an indication of the space dependence of the slowingdown time in finite systems. The experimental results were compared to the slowing-down times obtained from various theoretical approaches and from Monte Carlo calculations. All the methods show a decrease of the slowing-down time with decreasing size of the moderator. This effect was least pronounced in the experimental results, which can be explained by the fact the measurements are spatially dependent. The agreement between the Monte Carlo results and those obtained using the diffusion approximation or the age-diffusion theory is surprisingly good, especially for large systems. The P1 approximation, on the other hand, leads to an overestimation of the effect of the finite size on the slowing-down time. (author)

  4. "The End of Time" released - a film partly shot at CERN

    CERN Multimedia

    2012-01-01

    Qu’est-ce que le temps ? Une réalité ? Une illusion ? Un concept ? Ces questions sont au coeur du nouveau film de Peter Mettler. Avec The End of Time, guidé par son intuition et sa capacité d’émerveillement, Peter Mettler projette à nouveau le familier dans une dimension extraordinaire et nous donne à voir l’invisible.   Dix ans après Gambling, gods and LSD, son prodigieux essai visuel sur la transcendance, Peter Mettler revient avec un film d’une profonde et rare beauté. Troisième opus d’une trilogie commencée avec Picture of light (1996), puis Gambling, gods and LSD (2002), The End of Time confirme l'attachement de Mettler à un cinéma exigeant, résolument virtuose et visionnaire. Synopsis : Défi envers l’insaisissable sujet du temps entre le dicible et l’...

  5. Apprenticeship at CERN

    CERN Multimedia

    Staff Association

    2016-01-01

    In 1961, based on the finding that the evolution of the labour market created a growing need for qualified staff, a first agreement between the Republic and Canton of Geneva and CERN was signed. One of the objectives of this agreement was the vocational training of young electronics and physics laboratory technicians. CERN, an important stakeholder in the local economy, highlighted with this agreement its willingness to participate in the local social and economic development. The first apprentice arrived at CERN in 1965. In 1971, the apprenticeship centre was created; it now hosts over twenty apprentices in total and welcomes about six new apprentices each year. These apprenticeships are for young people aged between 15 and 21 years, coming from one of the CERN Member States, and having completed their mandatory education, e.g. 11th grade in Switzerland or 3ème in France. The training is divided between working time at CERN and one or two days per week at school (CFPT in Geneva for electronics or ...

  6. Cern Cricket Club

    CERN Multimedia

    Cern Cricket Club

    2014-01-01

      Cern Cricket Club The CERN Cricket Club 2014 season has started earlier than usual, with a game scheduled for the first time ever on Easter Sunday.  Due to repair work for the damage done to the ground because of the “Bosons&More” party at the end of September, all games until June have had to be scheduled away. Net practice, which normally takes place on the ground from mid-April, will not start until mid-June. The club is always looking for new players and newcomers will be made very welcome. Anyone who is interested in joining the club should sign up on our web site: http://cern.ch/Club-Cricket/    

  7. Dead time behaviors in passive neutron correlation counting

    International Nuclear Information System (INIS)

    Passive Neutron Coincidence Counting (PNCC) and Passive Neutron Multiplicity Counting (PNMC) based on (Multiplicity) Shift Register (M)(SR) pulse train correlation analyzers is a long established and important non destructive assay method used in the quantification of plutonium and other spontaneously fissile materials across the fuel cycle. Very high efficiency neutron chambers (>60%) are now available and are being applied to ever more demanding items including impure materials with a high (α, n) rate and articles with a high self-leakage multiplication. This trend means that high instantaneous count rates are commonly encountered such that the multiplicity histogram extends to high order; in other words the number of events detected in a single coincidence gate can be large. This poses a problem in that the likelihood of accidental (chance) coincidences due to random events and overlapping (super) fission histories increases and precision is lost in correcting for them. The epithermal design is one attempt to reduce the capture time distribution to minimize the accidentals coincidence rate but the field of application is so broad that high instantaneous rates are still encountered. This inevitably results in the need to apply a correction to the observed Singles, Doubles and Triples rate for dead time losses. When the instantaneous counting rate is high the uncertainties in the applied corrections can be the accuracy limiting factor in the derived counting rate. Controlling and compensating for dead time losses so that target accuracy is achieved is a crucial aspect of a successful design and implementation process. Dead time losses can be reduced substantially on new systems intended for special use by using dedicated preamplifier-discriminators for each 3He-filled proportional counter together with de-randomiser circuitry and fast encoding electronics. These adaptations are costly, however, and may be difficult to retrofit to existing systems. In this work we

  8. A detector for neutron imaging

    CERN Document Server

    Britton, C L; Wintenberg, A L; Warmack, R J; McKnight, T E; Frank, S S; Cooper, R G; Dudney, N J; Veith, G M; Stephan, A C

    2004-01-01

    A bright neutron source such as the Spallation Neutron Source (SNS) places extreme requirements on detectors including excellent 2-D spatial imaging and high dynamic range. Present imaging detectors have either shown position resolutions that are less than acceptable or they exhibit excessive paralyzing dead times due to the brightness of the source. High neutron detection efficiency with good neutron- gamma discrimination is critical for applications in neutron scattering research where the usefulness of the data is highly dependent on the statistical uncertainty associated with each detector pixel.. A detector concept known as MicroMegas (MicroMEsh GAseous Structure) has been developed at CERN in Geneva for high- energy physics charged-particle tracking applications and has shown great promise for handling high data rates with a rather low-cost structure. We are attempting to optimize the MicroMegas detector concept for thermal neutrons and have designed a 1-D neutron strip detector which we have tested In ...

  9. CERN internal communication is evolving

    CERN Multimedia

    2016-01-01

    CERN news will now be regularly updated on the CERN People page (see here).      Dear readers, All over the world, communication is becoming increasingly instantaneous, with news published in real time on websites and social networks. In order to keep pace with these changes, CERN's internal communication is evolving too. From now on, you will be informed of what’s happening at CERN more often via the “CERN people” page, which will frequently be updated with news. The Bulletin is following this trend too: twice a month, we will compile the most important articles published on the CERN site, with a brand-new layout. You will receive an e-mail every two weeks as soon as this new form of the Bulletin is available. If you have interesting news or stories to share, tell us about them through the form at: https://communications.web.cern.ch/got-story-cern-website​. You can also find out about news from CERN in real time...

  10. Managing the Real-time Behaviour of a Particle Beam Factory The CERN Proton Synchrotron Complex and its Timing System Principles

    CERN Document Server

    Bau, J C; Lewis, J; Philippe, J

    1998-01-01

    In the CERN 26 Gev Proton Synchrotron (PS) accelerator network, super-cycles are defined as sequences of different kinds of beams produced repetitively [Fig.1]. Each of these beams is characterised by attributes such as particle type, beam energy, its route through the accelerator network, and the final end user. The super-cycle is programmed by means of an editor through which the operational requirements of the physics programme can be described. Each beam in the normal sequence may later be replaced by a set of spare beams automatically depending on software and hardware interlocks and requests presented to the Master Timing Generator (MTG [Glos. 1]). The MTG calculates at run time how each beam is to be manufactured, and sends a telegram [Glos. 3] message to each accelerator, just before each cycle, describing what it should be doing now and during the next cycle. These messages, together with key machine timing events and clocks are encoded onto a timing distribution drop net where they are distributed a...

  11. Detectors for Time-of-Flight Fast-Neutron Radiography: 1. Neutron Counting Gas Detector

    OpenAIRE

    Dangendorf, V.; Breskin, A.; Chechik, R.; Goldberg, M; Laczko, G; Mor, I.; Reginatto, M.; Vartsky, D.

    2004-01-01

    One of our two methods for fast-neutron imaging with spectrometric capability is presented here. It is a neutron-counting technique based on a hydrogenous neutron converter coupled to Gaseous Electron Multipliers (GEM). The principles of the detection techniques and the optimization of the converter, electron amplification and the readout are described. Evaluation of the properties are derived from a experiment in a pulsed neutron beam of spectral distribution between 2 and 10 MeV

  12. Development and characterization of real-time wide-energy range personal neutron dosimeter

    International Nuclear Information System (INIS)

    The authors developed a real-time personal neutron dosimeter which could give neutron dose equivalent over wide energy region from thermal to 10 odd MeV by using 2 silicon detectors, fast neutron sensor and slow neutron sensor. The energy response of this dosimeter was evaluated under thermal neutron field, monoenergetic neutron field between 200 keV and 15 MeV, and moderated 252Cf neutron field. The neutron dose equivalent was estimated by adding neutron dose equivalent below 1 MeV given by slow neutron sensor and that above 1 MeV by fast neutron sensor. It was verified from various field tests that this dosimeter is able to give neutron dose equivalent within a factor of 2 margin of accuracy in reactor, accelerator, fusion research and nuclear fuel handling facilities. This dosimeter has more than one order higher sensitivity than conventional personal neutron dosimeters and is insensitive to γ-rays up to about 500 mSv/h. This dosimeter will soon be commercially available as a personal dosimeter which gives neutron and γ-ray dose equivalents simultaneously by installing γ-ray silicon sensor. (author)

  13. A proposal for fast neutron personal real time dosimetry in mixed n, γ fields

    International Nuclear Information System (INIS)

    A method for fast neutron monitoring has been studied, resulting from computer simulation analysis of fast neutron and gamma interaction responses in silicon counters. A real time personal dosemeter with a response accuracy better than 30% in a mixed n, γ field for neutron energies between 0.75 and 15 MeV is proposed. (author)

  14. Search for time reversal violation in neutron decay

    International Nuclear Information System (INIS)

    The topic of this thesis is the implementation of an experimental setup designed to measure the R- and N-parameters in polarized neutron decay, together with the data analysis. Four observables are necessary for this measurement: the neutron polarization, the electron momentum and both transverse components of the electron polarization. These last two are measured using a Mott polarimeter. The other observables are determined using the same detectors. The precision to be reached on the R-parameter is 0.5%. A non zero value would sign a time reversal invariance violation and therefore would be a hint of physics beyond the Standard Model. This document presents the work done to prepare and optimize the experimental setup before the data acquisition run performed in 2004. Particular care was taken on the scintillator walls, used to trigger the acquisition and measure the electron energy. The second part concerns the implementation of methods to extract R and N from the data, and the study of the background recorded simultaneously. (author)

  15. CERN openlab Open Day | 10 June

    CERN Multimedia

    2015-01-01

    CERN openlab is now entering an exciting new phase and is expanding to include other public research organisations for the first time. To mark this occasion, a first-of-its-kind ‘CERN openlab Open Day’ event will be held at CERN on 10 June 2015.   CERN openlab is a unique public-private partnership between CERN and leading ICT companies. Its mission is to accelerate the development of cutting-edge solutions to be used by CERN’s scientific community. The ‘CERN openlab Open Day’ event will take place in the Main Auditorium on 10 June and will be an opportunity to learn more about the work carried out through CERN openlab to help tackle the challenges faced by the scientific community. Find out more: http://indico.cern.ch/event/381083/

  16. A time-of-flight detector for thermal neutrons from radiotherapy Linacs

    Energy Technology Data Exchange (ETDEWEB)

    Conti, V. [Universita degli Studi di Milano and INFN di Milano (Italy)], E-mail: conti.Valentina@gmail.com; Bartesaghi, G. [Universita degli Studi di Milano and INFN di Milano (Italy); Bolognini, D.; Mascagna, V.; Perboni, C.; Prest, M.; Scazzi, S. [Universita dell' Insubria, Como and INFN di Milano (Italy); Mozzanica, A. [Universita degli Studi di Brescia and INFN sezione di Pavia (Italy); Cappelletti, P.; Frigerio, M.; Gelosa, S.; Monti, A.; Ostinelli, A. [Fisica Sanitaria, Ospedale S. Anna di Como (Italy); Giannini, G.; Vallazza, E. [INFN, sezione di Trieste and Universita degli Studi di Trieste (Italy)

    2007-10-21

    Boron Neutron Capture Therapy (BNCT) is a therapeutic technique exploiting the release of dose inside the tumour cell after a fission of a {sup 10}B nucleus following the capture of a thermal neutron. BNCT could be the treatment for extended tumors (liver, stomach, lung), radio-resistant ones (melanoma) or tumours surrounded by vital organs (brain). The application of BNCT requires a high thermal neutron flux (>5x10{sup 8}ncm{sup -2}s{sup -1}) with the correct energy spectrum (neutron energy <10keV), two requirements that for the moment are fulfilled only by nuclear reactors. The INFN PhoNeS (Photo Neutron Source) project is trying to produce such a neutron beam with standard radiotherapy Linacs, maximizing with a dedicated photo-neutron converter the neutrons produced by Giant Dipole Resonance by a high energy (>8MeV) photon beam. In this framework, we have developed a real-time detector to measure the thermal neutron time-of -flight to compute the flux and the energy spectrum. Given the pulsed nature of Linac beams, the detector is a single neutron counting system made of a scintillator detecting the photon emitted after the neutron capture by the hydrogen nuclei. The scintillator signal is sampled by a dedicated FPGA clock thus obtaining the exact arrival time of the neutron itself. The paper will present the detector and its electronics, the feasibility measurements with a Varian Clinac 1800/2100CD and comparison with a Monte Carlo simulation.

  17. Neutron activation analysis of medieval and early modern times ceramics

    International Nuclear Information System (INIS)

    Provenience studies of medieval and early modern times ceramics from the Eastern Danube area of Austria have been performed by instrumental neutron activation analysis. All sherds examined were selected from pottery which was specially charactrized by pottery marks ('Cross Potent', 'Crossmark within a circle', 'Latin Cross', 'Cross Paty'). With respect to the chemical composition five different pottery groups could be evaluated by cluster analysis. Archaeological results: The'Cross Patent' was used by different potter's workshops whereas the 'Crossmark within a circle' was more likely restricted to one manufacture entre. The distribution of the 'Latin Cross' and The 'Cross Paty' over all five clusters indicated the usage of clay from different deposits. The assignment of the 'Cross Paty' exclusively to the area of Passau could be disproved. (Author)

  18. CERN CAR CLUB

    CERN Multimedia

    Automobile club

    2009-01-01

    You are cordially invited to the next General Assembly of the CERN Car Club Tuesday 12 January 2010 at 5:45pm Bldg. 593 / room 11 As the end of 2009 is approaching, it is time to think about renewing your subscription. Therefore next time you are on the CERN-Meyrin site or at the Post Office counter don’t forget to fill in the payment slip to continue to be a part of our large family. The fee remains unchanged: 50 CHF. For those of you who are regular users of our equipment and who know of all the advantages that the club is in a position to offer, it seems pointless to give details, we are sure that many of you have made use of them and are satisfied. We remind you everyone working on CERN site is entitled to become a member of our club, this includes industrial support personnel and staff of companies which have a contract with CERN. If you are not yet a member, come and visit us! We will be happy to welcome you and show you the facilities, or you can visit our web site. The use of the club&...

  19. CERN's Guardian Angels

    CERN Multimedia

    2002-01-01

    Any trouble at CERN? The Technical Control Room operates the entire technical infrastructure of CERN every day, all year long. They deal with problems that go from simple water leaks to devastating power cuts.   The Technical Control Room with Kenneth Olesen and Mark Harvey, minutes before their starting time. This big room is probably the liveliest at CERN, since there's always someone there, everyday, all year long. Laurent Randot and Eric Lienard working in the Technical Control Room at CERN in building 212. They've started at 7 a.m. and today has been a relatively quiet day. There have been some microcuts in the electric net because of the wind. But these have been repaired rather quickly... The relief: It's 2.30 p.m. Time for Laurent Randot and Eric Lienard to show their colleagues Mark Harvey and Kenneth Olesen what has been going on during the morning. They are the next TCR team of the day. Mark Harvey and Kenneth Olesen start their working day. They will work until 11p.m., when another team wil...

  20. Moderation of Neutrons Emitted by a Pulsed Source and Neutron Spectrometry Based on Slowing-Down Time

    International Nuclear Information System (INIS)

    Over the past ten years research has been going on at the P.N. Lebedev Physics Institute on the non-stationary moderation of neutrons in heavy media, the development of a method of neutron spectrometry based on the slowing-down time and the use of this method in studying the energy dependence of the cross-sections of nuclear reactions produced by neutrons with energy up to 30 keV. The authors review this work and discuss the results achieved. After a brief discussion of the theory of the non-stationary moderation and thermalization of neutrons the authors set forth the results of experimental studies of neutron moderation in graphite, iron and lead, and of neutron thermalization in lead. Using a pulsed neutron source and resonance detectors the distribution of slowing-down times was measured up to a series of fixed values for final neutron energy. The results are compared with theory, which takes into account the thermal motion of the moderator atoms; in the case of lead this thermal motion leads to a measurable spread in the slowing-down times at energies below 10 eV. The relationship between the mean velocity of neutrons in lead and the slowing-down time is measured in the subcadmium energy range and a comparison made with multigroup theory. The procedure for determining the energy dependence of neutron reaction cross-sections by slowing-down time is described and the potentialities of this method of spectrometry discussed. There follows a brief discussion of the results obtained in two fields of spectrometric measurement. Firstly, precise measurement of the relative excitation functions of the following reactions: He3(n, p), Li6(n, α), B10(n, α) and N14(n, p) - the most interesting results being the discovery of a constant negative component of the reaction cross-section and indications of the existence of an excited He4 level. Secondly, measurement of the energy dependence of averaged radiative capture cross-sections. Measurements carried out on a large

  1. Improvements in neutron time-of-flight spectra processing

    International Nuclear Information System (INIS)

    At this conference Egan et. al. have reported on neutron scattering experiments on actinide nuclei with incident neutron energies in the 2 to 3 MeV range. These measurements present unique challenges because cross sections are small and excited levels are closely spaced. In this paper we review aspects of experiment design and of data reduction which assist in overcoming these difficulties (neutron scattering, actinides, elastic and inelastic cross sections, data reduction). (author)

  2. Stamp in honour of CERN

    CERN Multimedia

    1966-01-01

    21 February 1966. The Swiss post office issued a stamp in CERN's honour. This stamp showed the flags of the thirteen Member States at the time arranged in the geometrical outline of Switzerland against a background of a track photograph.

  3. Neutronics equations: Positiveness; compactness; spectral theory; time asymptotic behavior

    International Nuclear Information System (INIS)

    Neutronics equations are studied: the continuous model (with and without delayed neutrons) and the multigroup model. Asymptotic descriptions of these equations (t→+∞) are obtained, either by the Dunford method or by using semigroup perturbation techniques, after deriving the spectral theory for the equations. Compactness problems are reviewed, and a general theory of compact injection in neutronic functional space is derived. The effects of positiveness in neutronics are analyzed: the irreducibility of the transport semigroup, and the properties of the main eigenvalue (existence, nonexistence, frame, strict dominance, strict monotony in relation to all the parameters). A class of transport operators whose real spectrum can be completely described is shown

  4. Monoenergetic time-dependent neutron transport in an infinite medium with time-varying cross sections

    International Nuclear Information System (INIS)

    For almost 20 yr, the main thrust of the author's research has been the generation of as many benchmark solutions to the time-dependent monoenergetic neutron transport equation as possible. The major motivation behind this effort has been to provide code developers with highly accurate numerical solutions to serve as standards in the assessment of numerical transport algorithms. In addition, these solutions provide excellent educational tools since the important physical features of neutron transport are still present even though the problems solved are idealized. A secondary motivation, though of equal importance, is the intellectual stimulation and understanding provided by the combination of the analytical, numerical, and computational techniques required to obtain these solutions. Therefore, to further the benchmark development, the added complication of time-dependent cross sections in the one-group transport equation is considered here

  5. Development of real time personal neutron dosimeter with two silicon detectors

    International Nuclear Information System (INIS)

    The personal neutron dosimetry becomes more important with the increasing use of nuclear and accelerator facilities. The solid state track detector, film badge and thermo-luminescent dosimeter have widely been used as passive-type personal neutron dosimeters, but the real-time neutron dosimeter is strongly needed. A real time personal dosimeter which could give neutron dose equivalent over wide energy range from thermal to 10 odd MeV by using two neutron sensors has been developed by our group. For practical commercial product, some changes from these prototype sensors have recently been done by Fuji Electric Co. Ltd. The purpose of this work is the final performance test of the dosimeter just before sale. We checked again about the sensitivity in the monoenergetic neutron field from 8 keV to 15 MeV and in the neutron fields around a few accelerator facilities. (author)

  6. Design and manufacture of neutron time of flight spectrometer on China Advanced Research Reactor

    International Nuclear Information System (INIS)

    The cold or thermal neutron energy spectra on China Advanced Research Reactor (CARR) could be directly measured by neutron time of flight spectrometer. Spectrometer structure and selected parameters of its key components were introduced. The impact of chopper slit and flux limit slit on neutron counts and pulse width was analyzed. The formulas of neutron counts and pulse width which were dependent on neutron wavelength were acquired. According to neutron energy spectrum measurement requirement for high fluence rate neutron beam, low-sensitivity detector, detector flux limit slit and multi-channel scaler for data acquisition were selected. These would ensure that the count loss rate was less than 0.5%. Electronics framework of detection system was designed and the total resolution time was 22.15-29.46 μs. (authors)

  7. CERN: 50 and counting

    International Nuclear Information System (INIS)

    Fifty years is a long time in particle physics - and not just because most subatomic particles only exist for tiny fractions of a second. In 1954, the year that CERN was established, the leading high-energy laboratories in the US, and indeed the world, were at Berkeley in California and Brookhaven in New York. Today these two labs - with nine Nobel prizes for discoveries in particle physics between them - have been replaced by Stanford (established in 1962) and Fermilab (1967) as the focal points of high-energy physics in the US. CERN did not reach its current position of strength overnight. In the early years it struggled as US labs dominated the field and beat Europe's new lab to the big discoveries. The tide turned with the detection of weak neutral currents in 1973, and the discovery of the W and Z bosons 10 years later showed that CERN was capable of making truly massive discoveries. Today, completing the Large Hadron Collider (LHC) and its four detectors on schedule and within budget, and then ensuring that they run reliably from 2007 onwards, are CERN's top priorities. (U.K.)

  8. A heatwave at CERN

    CERN Multimedia

    Anaïs Schaeffer

    2011-01-01

    It's getting hot in Buildings 201 and 860, over-heating even... But no reason to panic! We're talking about the superheated water boilers of CERN's two heating plants, which heat all the buildings on the Meyrin and Prévessin sites.   View of the three boilers and the control centre of the Meyrin heating plant. CERN's two heating plants each comprise three gas* boilers, with generators of 15 MW in the case of Meyrin and 5 MW in the case of Prévessin. Both inject pressurised water, superheated to 125 degrees, into several kilometres of pipes, 22 km on the Meyrin site and 5 km in Prévessin. "A single boiler is sufficient most of the time but a second kicks in automatically during very cold weather, and a third is there on stand-by," explains Christophe Martel, head of the GS Department section responsible for CERN's heating and air-conditioning systems. All of CERN's buildings have a sub-station that receives the superheated water from the boilers an...

  9. Neutrinos at CERN

    International Nuclear Information System (INIS)

    CERN's long and distinguished neutrino tradition began in 1958 at the then new 500 MeV synchrocyclotron (SC) with the first observation of the decay of a charged pion into an electron and a neutrino. At that time, the first ideas on the special (vector/axial vector) structure of the weak interactions had been put forward by Feynman and Gell-Mann and by Marshak and Sudarshan, but the continual non-observation of that charged pion decay was holding up progress. This decay is only one part in ten thousand, and is masked by the dominant muon-neutrino channel. A special telescope was built to pick up the high energy electrons from the pion decay. In 1962 came another SC neutrino success, with the first measurement of the decay of a charged pion into a neutral one, with emission of an electron and a neutrino. Meanwhile the main thrust of CERN's neutrino effort was taking shape at the PS. By the close of 1960, CERN had decided to attack neutrino physics using several detectors - a 1m heavy liquid bubble chamber from Andre Lagarrigue's team in Paris, a CERN 1 m heavy liquid bubble chamber, and a hybrid chamber/counter from a group led by Helmut Faissner

  10. CERN Women's club

    CERN Multimedia

    CERN Women's club

    2010-01-01

    The Welcome Center The Welcome Center website for CERN newcomers – and everyone else at CERN – has celebrated its first anniversary in operation. It began as a project to organize all the various information available at CERN into an easy to use site, with advice to help you make the most of your time here. It continues to be updated as new information becomes available. Lori Hakulinen and her helpers offer to meet with anyone who has questions. They can advise you on weekend activities, local restaurants and where to buy hard to find items or some of your favorite things from home, in addition to all of the practicalities you need to know, such as how to find housing or have a telephone installed, where to take language classes and much, much more. It’s all listed at: http://cern.ch/club-cwc-newcomers In general, meetings take place the first and third Thursdays in the month at Restaurant No. 1 in the Children’s Dining Room. (Please consult the Homepage for schedu...

  11. Electron linac based pulsed white neutron sources for high resolution neutron time of flight spectroscopy - status and perspectives

    International Nuclear Information System (INIS)

    With r.f. linacs nowadays intense, subnanosecond bursts of neutrons can be produced which allow neutron time of flight measurements in a range covering in favourable cases 11 decades of neutron energy (1 meV-100 MeV). The number of neutrons contained in such short bursts is larger that the corresponding numbers generated with the short burst spallation source at LAMPF and with the Karlsruhe cyclotron. The considerably larger average neutron intensities at the latter two accelerators are due to the much higher pulse repetition frequencies. This advantage is cancelled if pulse overlap conditions require a reduction of the p.r.f. down to the level at which electron linacs operate. Taking this into account the contemporary linac equipped with a subnanosecond pulsing facility like GELINA continues to offer the best intensity/resolution performance for neutron time of flight spectroscopy between 10 keV and a few MeV. At very low (meV range) and at high (> some ten MeV) neutron energies the LAMPF neutron sources occupy with distinction the first rank while in the low MeV range the KFK cyclotron is clearly superior to electron linacs and competitive with the LAMPF short burst satellite source. Plans or thoughts to replace some electron linacs by more powerful accelerators have existed for several years. So far none of them has had the chance of realization. Instead of going the way of completely new and very expensive concepts which carry a non-negligible technological risk, for the field of applied neutron nuclear data the following two approaches are suggested: a) Case of dominant interest in neutron data for fission reactors: Exploitation of the L-band linac to the same level as it is done for S-band linacs, including post acceleration pulse compression. b) Case of dominant interest in neutron data for fusion reactors: Use of KFK cyclotron type source. With 70 MeV deuterons on uranium a hundred times more neutrons would be available at 14 MeV than with contemporary

  12. Performance of a liquid argon time projection chamber exposed to the CERN West Area Neutrino Facility neutrino beam

    International Nuclear Information System (INIS)

    We present the results of the first exposure of a Liquid Argon TPC to a multi-GeV neutrino beam. The data have been collected with a 50 liters ICARUS-like chamber located between the CHORUS and NOMAD experiments at the CERN West Area Neutrino Facility (WANF). We discuss both the instrumental performance of the detector and its capability to identify and reconstruct low-multiplicity neutrino interactions

  13. UK @ CERN

    CERN Multimedia

    FI Department

    2008-01-01

    17 – 18 November 2008 9.00 a.m. - 5.00 p.m. on Monday 17 November 9.00 a.m. - 5.00 p.m. on Tuesday 18 November Individual meetings will take place in the technicians’ or engineers’ offices. The companies will contact relevant users/technicians but anyone wishing to arrange an appointment with a specific company can contact Caroline Laignel (mailto:caroline.laignel@cern.ch, tel. 73722). A list of the companies is available from all departmental secretariats and on the web at: http://fi-dep.web.cern.ch/fi-dep/structure/memberstates/exhibitions_visits.htm List of companies: 1. Caburn MDC Europe Ltd. 2. Croft Engineering Services 3. Cryox Ltd. 4. Goodfellow Cambridge Ltd. 5. Gravatom Engineering Systems Ltd. 6. High Voltage Technology 7. Lilco Ltd. 8. Micro Metalsmiths Ltd. 9. Photek Ltd. 10. Shadow Robot Company 11. Sundance Multiprocessor Technology Ltd. 12. Tessella plc 13. Thermal Resources Management Ltd. 14. Torr Scientific Ltd. For further information please contact Mrs C. Laignel, FI-DI, tel. 7372...

  14. CERN moves to http://home.cern

    CERN Multimedia

    2015-01-01

    A new top-level domain for CERN will be inaugurated next week, with the migration of the core website to http://home.cern.   The new home.cern webpage. The .cern top-level domain is intended for the exclusive use of CERN and its affiliates, and will soon be open for applications from within the community. Clear governance mechanisms for registration and management of .cern domains have been put in place. Applications for domains may be submitted by current members of the CERN personnel, and must be sponsored by a CERN entity such as a department, experiment, project or CERN-recognised experiment. For more information please refer to the registration policy. The acquisition of the .cern top-level domain was negotiated via ICANN’s new gTLD programme by a board comprising members of the CERN Legal Service, Communications group and IT department. .cern is one of over 1,300 new top-level domains that will launch over the coming months and years. The .cern domain nam...

  15. CERN – better than science fiction!

    CERN Multimedia

    2007-01-01

    From left to right: Allan Cameron (Production Designer), Sam Breckham (Location Manager), James Gillies (Head of Communication at CERN), Jacques Fichet (from the CERN Audiovisual Service), Rolf Landua (former spokesman of the ATHENA antihydrogen experiment at CERN and Head of CERN’s Education Group), Ron Howard, and Renilde Vanden Broeck (CERN press officer). The two-time Academy Award-winning American film director, Ron Howard, recently visited CERN for background research in preparation for his new film Angels and Demons, based on the book by Dan Brown. He also filmed the adaption of Brown’s bestselling novel The Da Vinci Code last year.

  16. Time-of-flight discrimination between gamma-rays and neutrons by neural networks

    OpenAIRE

    Akkoyun, Serkan

    2012-01-01

    In gamma-ray spectroscopy, a number of neutrons are emitted from the nuclei together with the gamma-rays and these neutrons influence gamma-ray spectra. An obvious method of separating between neutrons and gamma-rays is based on the time-of-flight (tof) technique. This work aims obtaining tof distributions of gamma-rays and neutrons by using feed-forward artificial neural network (ANN). It was shown that, ANN can correctly classify gamma-ray and neutron events. Testing of trained networks on ...

  17. Isotope identification capabilities using time resolved prompt gamma emission from epithermal neutrons

    International Nuclear Information System (INIS)

    We present a concept of integrated measurements for isotope identification which takes advantage of the time structure of spallation neutron sources for time resolved γ spectroscopy. Time resolved Prompt Gamma Activation Analysis (T-PGAA) consists in the measurement of gamma energy spectrum induced by the radioactive capture as a function of incident neutron Time Of Flight (TOF), directly related with the energy of incident neutrons. The potential of the proposed concept was explored on INES (Italian Neutron Experimental Station) at the ISIS spallation neutron source (U.K.). Through this new technique we show an increase in the sensitivity to specific elements of archaeometric relevance, through incident neutron energy selection in prompt γ spectra for multicomponent samples. Results on a standard bronze sample are presented

  18. CERN firemen share their expertise

    CERN Multimedia

    Maximilien Brice

    2002-01-01

    Firemen from local fire brigades have been coming to CERN to learn modern fire-fighting techniques. The CERN firemen have some unique training equipment for two particularly dangerous fire hazards, flashover and backdraft. Backdraft occurs when a fire smoulders for a long time within a confined space. The gases produced by the embers fail to burn owing to a lack of oxygen. When the door of the room is opened, for example, the resulting inflow of oxygen causes a deflagration that may prove fatal. This series of photos shows the use of special apparatus to simulate the spectacular backdraft phenomenon, so that firemen training at CERN learn to understand it.

  19. CERN Services Availability during the CERN Annual Closure 2011

    CERN Multimedia

    IT & GS Departments

    2011-01-01

    General Services: Most of the services provided by the GS Department that do not depend on continuous human presence will remain available during the CERN annual closure. Support levels are reduced during this period, in general the target reaction time for problems will be ½ day. Apart from the heating system, no interruptions are scheduled. In case of failure, the reaction time for restoration of services depends on the arrangements that have been made on a service by service level. Incidents will be documented at http://gssb.web.cern.ch/ For more detailed information please consult the service-portal (http://cern.ch/service-portal). Computing Services Most of the services provided by the IT Department - including WLCG production services - will remain available during the CERN annual closure. No interruptions are scheduled but in case of failure, the restoration of services cannot be guaranteed. Problems will be dealt with on a best effort basis only. However, please note: Experts shoul...

  20. Neutron noise analysis of BWR using time series analysis

    International Nuclear Information System (INIS)

    The main purpose of this paper is to give more quantitative understanding of noise source in neutron flux and to provide a useful tool for the detection and diagnosis of reactor. The space dependent effects of distributed neutron flux signals at the axial direction of two different strings are investigated by the power contribution ratio among neutron fluxes and the incoherent noise spectra of neutron fluxes derived from autoregressive spectra. The signals are measured on the medium sized commercial BWR of 460 MWe in Japan. From the obtained results, local and global noise sources in neutron flux are discussed. This method is indicated to be a useful tool for detection and diagnosis of anomalous phenomena in BWR. (orig./RW)

  1. Time-dependent density-functional studies on strength functions in neutron-rich nuclei

    OpenAIRE

    Ebata, Shuichiro; Inakura, Tsunenori; Nakatsukasa, Takashi

    2013-01-01

    The electric dipole (E1) strength functions have been systematically calculated based on the time-dependent density functional theory (TDDFT), using the finite amplitude method and the real-time approach to the TDDFT with pairing correlations. The low-energy E1 strengths in neutron-rich isotopes show peculiar behaviors, such as sudden enhancement and reduction, as functions of the neutron numbers.They seem to be due to the interplay between the neutron shell effect and the deformation effect.

  2. Time-resolved fast-neutron imaging with a pulse-counting image intensifier

    OpenAIRE

    Dangendorf, Volker; Lauck, Ronald; Kaufmann, Frank; Barnstedt, Juergen; Breskin, Amos; Jagutzki, Ottmar; Kraemer, Michael; Vartsky, David

    2006-01-01

    A new imaging method that combines high-efficiency fast-neutron detection with sub-ns time resolution is presented. This is achieved by exploiting the high neutron detection efficiency of a thick scintillator and the fast timing capability and flexibility of light-pulse detection with a dedicated image intensifier. The neutron converter is a plastic scintillator slab or, alternatively, a scintillating fibre screen. The scintillator is optically coupled to a pulse counting image intensifier wh...

  3. President of Chile at CERN

    CERN Multimedia

    2007-01-01

    The President of Chile, Michelle Bachelet, in the ATLAS cavern with, from left to right, Peter Jenni, ATLAS Spokesman, Vivian Heyl, CONICYT President, and Robert Aymar, CERN Director-General. Robert Aymar, CERN Director-General, and Vivian Heyl, CONICYT President, signing a cooperation agreement between CERN and Chile’s Comisión Nacional de Investigación Científica y Tecnológica (CONICYT).The President of Chile, Michelle Bachelet, paid a visit to CERN during her three-day tour of Switzerland. The charismatic Michelle Bachelet and her large delegation were greeted by the CERN Director-General and then taken to see the ATLAS experiment and the LHC. She also took time to meet the Chilean community working at CERN, comprising several physicists in the Theory Group and the ATLAS experiment. The meeting was followed by the signing of a cooperation agreement between CERN and Chile’s Comisión Nacional de Investigación Científi...

  4. A transistorized 1024-channel neutron time-of-flight analyser

    International Nuclear Information System (INIS)

    A transistorized 1024-channel neutron time-of-flight analyser is described. This instrument has been divided in two fully independent parts: the analogue-to-digital converter (ADC) that measures the time-of-flight and the 1024-channel ferrite-core memory. In this way the output signals coming from the ADC can be recorded on a magnetic tape together with the output from other ADCs which measure other physical quantities related to the same nuclear event, with an overall number of channels higher than the capacity of the memory. The AD converter is provided with a temporary memory that, by its regularizing action on the signals rate, (1) when the AD converter, directly connected to the 1024-channel memory, allows a dead time of only 0.5 μs, and (2) when the AD converter drives a magnetic tape recorder and allows a better utilization of the magnetic tape itself. The temporary memory has a capacity of four numbers of up to sixteen bits. The channel-width of the analyser is variable from 0.5 up to 48 μs. The 1024 channels can be divided in two contemporary groups of 512, each connected to two detectors. The temporary memory allows contemporary recordings of signals into the two groups. The channels can also be subdivided over the time-of-flight in two groups of which the first (of 16 channels) is used to record the true zero time of the time-of-flight, while the second group can be set in any position over the total time-of-flight interval. The number of channels used in the recording of the time-of-flight can be reduced in order to record another quantity with 1024 overall channels. The logical design of the instrument is described. In the design advantage has been taken of the possibilities offered by the transistorization and the related mechanical construction systems in order to produce a most flexible instrument and one in which future modifications or extensions, which may be required by the experimenters, are feasible. (author)

  5. A neutron Albedo system with time rejection for landmine and IED detection

    Energy Technology Data Exchange (ETDEWEB)

    Kovaltchouk, V.D., E-mail: kovaltchoukv@bubbletech.ca [Bubble Technology Industries, Chalk River, Ontario (Canada); Andrews, H.R.; Clifford, E.T.H. [Bubble Technology Industries, Chalk River, Ontario (Canada); Faust, A.A. [Defense R and D Canada-Suffield, Medicine Hat, Alberta (Canada); Ing, H. [Bubble Technology Industries, Chalk River, Ontario (Canada); McFee, J.E. [Defense R and D Canada-Suffield, Medicine Hat, Alberta (Canada)

    2011-10-01

    A neutron Albedo system has been developed for imaging of buried landmines and improvised explosive devices (IEDs). It involves irradiating the ground with fast neutrons and subsequently detecting the thermalized neutrons that return. A scintillating {sup 6}Li loaded ZnS(Ag) screen with a sensitive area of 40 cmx40 cm is used as a thermal neutron detector. Scintillation light is captured by orthogonal arrays of wavelength-shifting fibers placed on either side of the scintillator surface and then transferred to X and Y multi-pixel PMTs. A timing circuit, used with pulsed neutron sources, records the time when a neutron detection takes place relative to an external synchronization pulse from the pulsed source. Experimental tests of the Albedo system performance have been done in a sand box with a {sup 252}Cf neutron source (no time gating) and with pulsed D-D (2.6 MeV) neutrons from the Defense R and D Ottawa Van de Graaff accelerator (with time gating). Information contained in the time evolution of the thermal neutron field provided improved detection capability and image reconstruction. The detector design is described and experimental results are discussed.

  6. Digital determination of TR-I control rod worths and time behaviour of neutron flux

    International Nuclear Information System (INIS)

    In this work, the control rod reactivity worth of the swimming-pool type reactor (TR-I) in CNAEM, Cekmece Nuclear Research and Training Centre has been measured digitally and the mean neutron lifetime has been estimated by a special miniature fission chamber with 60 nanosecond resolving time. The time behaviour of thermal neutrons is also compared with reactor control console results. (orig.)

  7. CERN: Towards LEP 200

    International Nuclear Information System (INIS)

    In March a cryomodule with four superconducting radiofrequency accelerating cavities operated for the first time in CERN's new LEP electron-positron collider, the result of many years of careful research and development work and an important step on the road to boost LEP energies from their initial level around 50 GeV per beam to above the 82 GeV threshold for production of W pairs

  8. CERN access cards

    CERN Multimedia

    HR Department

    2007-01-01

    Holders of CERN access cards are reminded that the card is an official document. It is important to carry it with you at all times when you are on the site. This applies also to those on standby duty who are called out for emergency interventions. As announced in Weekly Bulletin 13/2006, any loss or theft of access cards must be declared to the competent external authorities.

  9. CERN Electronics Pool presentations

    CERN Multimedia

    2011-01-01

    The CERN Electronics Pool has organised a series of presentations in collaboration with oscilloscope manufacturers. The last one will take place according to the schedule below.   Time will be available at the end of the presentation to discuss your personal needs. The Agilent presentation had to be postponed and will be organised later. -     Lecroy: Thursday, 24 November 2011, in 530-R-030, 14:00 to 16:30.

  10. The Duke of York visits CERN

    CERN Multimedia

    2004-01-01

    The Duke of York chats before inaugurating the UK@CERN exhibition. From left to right: Robert Aymar, CERN's Director General, the Duke of York, and leading UK scientists at CERN: Jim Virdee, CMS deputy spokeman; theorist John Ellis ; and Steve Myers, head of the AB Department. On 23 November, the Duke of York visited CERN and, in his capacity as the UK's Special Representative for International Trade and Investment, inaugurated the UK@CERN Exhibition. This biennial trade show was initially held in 1968, the first such exhibition by a CERN member state. This year 22 companies displayed goods and services that could be of interest to CERN scientists. In his inaugural speech, the Duke emphasized that business between companies and CERN "is a two-way information flow with mutual benefits." The companies make sales but also benefit from technologies that CERN transfers to them. CERN benefits from the exchange, the Duke said, addressing CERN's scientists, because it "frees your time for what you do best: science....

  11. LHCb: Beam and Background Monitoring and the Upgrade of the Timing and Fast Control System of the LHCb experiment at CERN

    CERN Multimedia

    Alessio, F

    2009-01-01

    The LHCb experiment at CERN is preparing for first real data taking, foreseen by the end of the year 2009 with the start-up of the LHC. A large amount of work of commissioning, tests and improvements of the full detector has been done in order to optimize its performance. During my first year as a Doctoral Student at CERN, I have been working on the timing and readout control of the LHCb experiment in the frame of the LHCb Online group. The group is responsible for the full data acquisition of the LHCb experiment, from the Front-End Electronics (FEE) to the storage of the data for offline analysis, as well as the Timing and Fast Control (TFC) system. The latter controls and distributes centrally timing and trigger information, as well as synchronous and asynchronous commands to the readout system. It is also responsible for receiving and adjusting the bunch and orbit clocks of the LHC machine and distributing it to the electronics of the whole experiment. It is of vital importance to assure that the timing o...

  12. The multipurpose time-of-flight neutron reflectometer “Platypus” at Australia's OPAL reactor

    Science.gov (United States)

    James, M.; Nelson, A.; Holt, S. A.; Saerbeck, T.; Hamilton, W. A.; Klose, F.

    2011-03-01

    In this manuscript we describe the major components of the Platypus time-of-flight neutron reflectometer at the 20 MW OPAL reactor in Sydney, Australia. Platypus is a multipurpose spectrometer for the characterisation of solid thin films, materials adsorbed at the solid-liquid interface and free-liquid surfaces. It also has the capacity to study magnetic thin films using spin-polarised neutrons. Platypus utilises a white neutron beam ( λ=2-20 Å) that is pulsed using boron-coated disc chopper pairs; thus providing the capacity to tailor the wavelength resolution of the pulses to suit the system under investigation. Supermirror optical components are used to focus, deflect or spin-polarise the broad bandwidth neutron beams, and typical incident spectra are presented for each configuration. A series of neutron reflectivity datasets are presented, indicating the quality and flexibility of this spectrometer. Minimum reflectivity values of Platypus time-of-flight neutron reflectometer are presented.

  13. Calculation of the neutron importance and weighted neutron generation time using MCNIC method in accelerator driven subcritical reactors

    International Nuclear Information System (INIS)

    Highlights: • All reactor kinetic parameters are importance weighted quantities. • MCNIC method has been developed for calculating neutron importance in ADSRs. • Mean generation time has been calculated in spallation driven systems. -- Abstract: The difference between non-weighted neutron generation time (Λ) and the weighted one (Λ†) can be quite significant depending on the type of the system. In the present work, we will focus on developing MCNIC method for calculation of the neutron importance (Φ†) and importance weighted neutron generation time (Λ†) in accelerator driven systems (ADS). Two hypothetic bare and graphite reflected spallation source driven system have been considered as illustrative examples for this means. The results of this method have been compared with those obtained by MCNPX code. According to the results, the relative difference between Λ and Λ† is within 36% and 24,840% in bare and reflected illustrative examples respectively. The difference is quite significant in reflected systems and increases with reflector thickness. In Conclusion, this method may be used for better estimation of kinetic parameters rather than the MCNPX code because of using neutron importance function

  14. Time analysis of the slow neutron field generated by the accelerating tube downhole

    International Nuclear Information System (INIS)

    Pulsed neutron logging (PNL) consists in the irradiation of rocks around the well by a pulsed periodic flux of fast neutrons generated by a portable accelerating tube and detection of thermal neutrons during pauses between the neutron pulses. The main aim of the PNL is determining the time distribution of thermal neutrons in the well and formation. At present the PNL response is considered as the sum of two exponentially decaying components, one related to the well and another one - to rock formation: J(t) = A1 exp (-λ1t) + A2 exp (-λ2t) . This is a result of homogenization of a neutron field in the borehole and formation space which is characterized by complicated radial structure and heterogeneous neutron properties. The time base of measurements T is subdivided into a set consisting of I narrow time windows Δt and the PNL response is formed as the series of neutron registration events Ni for each time window Δt with number i =1 to I (time neutron spectrum). Presented is a noise-immune algorithm for decomposition of the experimental time neutron spectrum into two components using the following overdetermined system of equations: Ni - Δt (λ1 + λ2) Σk=i Nk + (Δt)2 λ1λ2 Σk=i Σj=k Nj + [T - (i - 1) Δt][J'(T) - (λ1 + λ2) J(T)]Δt - J(T) Δt 0. Two amplitudes and two time decay constants of these components give an information about the neutron absorption cross-section and porosity of rocks. Presented are physical characteristics of new Russian PNL tools and examples illustrating the processing of PNL in oil wells. (author)

  15. TDTORT: Time-Dependent, 3-D, Discrete Ordinates, Neutron Transport Code System with Delayed Neutrons

    International Nuclear Information System (INIS)

    1 - Description of program or function: TDTORT solves the time-dependent, three-dimensional neutron transport equation with explicit representation of delayed neutrons to estimate the fission yield from fissionable material transients. This release includes a modified version of TORT from the C00650MFMWS01 DOORS3.1 code package plus the time-dependent TDTORT code. GIP is also included for cross-section preparation. TORT calculates the flux or fluence of particles due to particles incident upon the system from extraneous sources or generated internally as a result of interaction with the system in two- or three-dimensional geometric systems. The principle application is to the deep-penetration transport of neutrons and photons. Reactor eigenvalue problems can also be solved. Numerous printed edits of the results are available, and results can be transferred to output files for subsequent analysis. TDTORT reads ANISN-format cross-section libraries, which are not included in the package. Users may choose from several available in RSICC's data library collection which can be identified by the keyword 'ANISN FORMAT'. 2 - Methods:The time-dependent spatial flux is expressed as a product of a space-, energy-, and angle-dependent shape function, which is usually slowly varying in time and a purely time-dependent amplitude function. The shape equation is solved for the shape using TORT; and the result is used to calculate the point kinetics parameters (e.g., reactivity) by using their inner product definitions, which are then used to solve the time-dependent amplitude and precursor equations. The amplitude function is calculated by solving the kinetics equations using the LSODE solver. When a new shape calculation is needed, the flux is calculated using the newly computed amplitude function. The Boltzmann transport equation is solved using the method of discrete ordinates to treat the directional variable and weighted finite-difference methods, in addition to Linear Nodal

  16. The new Athens center on data processing from the neutron monitor network in real time

    OpenAIRE

    Mavromichalaki; Souvatzoglou; Sarlanis; Mariatos; Gerontidou; Papaioannou; Plainaki; Tatsis; Belov; Eroshenko; Yanke

    2005-01-01

    International audience The ground-based neutron monitors (NMs) record galactic and solar relativistic cosmic rays which can play a useful key role in space weather forecasting, as a result of their interaction with interplanetary disturbances. The Earth's-based neutron monitor network has been used in order to produce a real-time prediction of space weather phenomena. Therefore, the Athens Neutron Monitor Data Processing Center (ANMODAP) takes advantage of this unique multi-directional dev...

  17. Quick algorithms for real-time discrimination of neutrons and gamma rays

    OpenAIRE

    Amiri, Moslem; Přenosil, Václav; Cvachovec, František; Matěj, Zdeněk; Mravec, Filip

    2014-01-01

    Several new methods for the digital discrimination of neutrons and gamma-rays in a mixed radiation field are presented. The methods introduced discriminate neutrons and gamma rays successfully in the digital domain. They are mathematically simple and exploit samples during the life time of the pulse, hence appropriate for field measurements. All these methods are applied to a set of mixed neutron and photon signals from a stilbene scintillator and their discrimination qualities are compared.

  18. Quick algorithms for real-time discrimination of neutrons and gamma rays

    International Nuclear Information System (INIS)

    Several new methods for the digital discrimination of neutrons and gamma-rays in a mixed radiation field are presented. The methods introduced discriminate neutrons and gamma rays successfully in the digital domain. They are mathematically simple and exploit samples during the life time of the pulse, hence appropriate for field measurements. All these methods are applied to a set of mixed neutron and photon signals from a stilbene scintillator and their discrimination qualities are compared. (author)

  19. The Local-time variations of Lunar Prospector epithermal-neutron data

    OpenAIRE

    Teodoro, L F A; Lawrence, D.J.; Eke, V. R.; Elphic, R. E.; Feldman, W. C.; Maurice, S.; Siegler, M. A.; Paige, D. A.

    2015-01-01

    We assess local-time variations of epithermal-neutron count rates measured by the Lunar Prospector Neutron Spectrometer. We investigate the nature of these variations and find no evidence to support the idea that such variations are caused by diurnal variations of hydrogen concentration across the lunar surface. Rather we find an anticorrelation between instrumental temperature and epithermal-neutron count rate. We have also found that the measured counts are dependent on the temperatures of ...

  20. A Differential Time-of-flight Spectrometer of Very Slow Neutrons

    CERN Document Server

    Pokotilovski, Yu N; Geltenbort, P; Brenner, Th

    2011-01-01

    A time-of-flight spectrometer of neutrons in the energy range (0.05 -- 2.5)$\\mu$eV is described. This spectrometer has been tested my measuring the total and differential neutron cross sections for a number of materials: Al, Cu, $^{6}$LiF, Si, Zr, teflon, polyethylene and liquid fluoropolymers, that are essential for experiments in the physics of ultracold neutrons.

  1. CERN Courier goes digital

    CERN Multimedia

    Christine Sutton, CERN Courier editor

    2013-01-01

    The January/February 2013 issue of the CERN Courier offers a new way to access the content – the first digital edition of the magazine.   The CERN Courier dates back to August 1959, when the first issue appeared, consisting of 8 black-and-white pages. Since then it has seen many changes in design and layout, leading to the current full-colour editions of more than 50 pages on average. It went on the web for the first time in October 1998, when IOP Publishing took over the production work. Now, we have taken another step forward with a digital edition that provides yet another means to access the content beyond the web and print editions, which continue as before. To download the digital edition, click here. To sign up to the new issue alert, please visit: http://cerncourier.com/cws/sign-up.

  2. Belgian Firms Visit CERN

    CERN Multimedia

    2001-01-01

    Fifteen Belgian firms visited CERN last 2 and 3 April to present their know-how. Industrial sectors ranging from precision machining to electrical engineering and electronics were represented. And for the first time, companies from the Flemish and Brussels regions of the country joined their Walloon compatriots, who have come to CERN before. The visit was organised by Mr J.-M. Warêgne, economic and commercial attaché at the Belgian permanent mission for the French-speaking region, Mr J. Van de Vondel, his opposite number for the Flemish region, and Mrs E. Solowianiuk, economic and commercial counsellor at the Belgian permanent mission for the Brussels-Capital region.

  3. Ombud's Corner: Respect @ CERN

    CERN Document Server

    Sudeshna Datta-Cockerill

    2014-01-01

    Since 2010 CERN has been a member of the Geneva-based association "Le respect, ça change la vie". Four years later and in conjunction with CERN’s celebration of its 60 years of ‘science for peace’, it is time to launch a new respectful workplace awareness campaign under the auspices of the Ombud.   Mutual respect is a basic pillar of peace. At CERN, we pride ourselves on our history, which started when a handful of Europe’s visionary scientists saw the opportunity that an international laboratory for fundamental research would present in bringing nations together. That idea has worked very well and, today, our success can be measured not only in terms of unprecedented scientific achievements but also in terms of training and education, and exemplary collaboration across borders, cultures and an extensive range of differences. In order for history to continue along these positive lines, and coming back to the awareness campai...

  4. CERN: Accelerator school

    International Nuclear Information System (INIS)

    Full text: Jyvaskyla, a university town in central Finland, was the setting for last year's General Accelerator School organized by the CERN Accelerator School. Well over a hundred students - more than for some time - followed two weeks of lectures on a broad spectrum of accelerator topics, the first step en route to becoming the designers, builders and operators of the surprisingly large number of, accelerators of all kinds either built or planned throughout Europe and further afield. This was the fifth such school organized by CAS in a biennial cycle which alternates this introductory level with more advanced tuition. The next, advanced, school will be from 20 October - 1 November, hosted by Athens University on the Greek Island of Rhodes. (Application details will become available in Spring but would-be participants should already reserve the dates.) After Finland, the CAS caravan moved to Benalmadena near Malaga in Spain where, together with Seville University, they organized one of the joint US-CERN schools held every two years and focusing on frontier accelerator topics. This time the subject was electron-positron factories - machines for high luminosity experiments in phi, tau-charm, beauty and Z physics. Experts from both sides of the Atlantic and from Japan shared their knowledge with an equally representative audience and probed the many intensity related phenomena which must be mastered to reach design performance. A number of these topics will receive extended coverage in the next specialist CAS School which is a repeat - by public demand - of the highly successful radiofrequency course held in Oxford in 1991. This school will be in Capri, Italy, with the support of the University of Naples from 29 April to 5 May. Details and application forms are now available by e-mail (CASRF@CERNVM.CERN.CH), by fax (+41 22 7824836) or from Suzanne von Wartburg, CERN Accelerator School, 1211 Geneva 23, Switzerland

  5. UK @ CERN

    CERN Multimedia

    FI Department

    2008-01-01

    17 – 18 November 2008 9.00 a.m. - 5.00 p.m. on Monday 17 November 9.00 a.m. - 5.00 p.m. on Tuesday 18 November Individual meetings will take place in the technicians’ or engineers’ offices. The companies will contact relevant users/technicians but anyone wishing to arrange an appointment with a specific company can contact Caroline Laignel (caroline.laignel@cern.ch, tel. 73722). A list of the companies is available from all departmental secretariats and on the web here. List of companies: 1. Caburn MDC Europe Ltd. 2. Croft Engineering Services 3. Cryox Ltd. 4. Goodfellow Cambridge Ltd. 5. Gravatom Engineering Systems Ltd. 6. High Voltage Technology 7. Lilco Ltd. 8. Micro Metalsmiths Ltd. 9. Photek Ltd. 10. Shadow Robot Company 11. Sundance Multiprocessor Technology Ltd. 12. Tessella plc 13. Thermal Resources Management Ltd. 14. Torr Scientific Ltd. For further information please contact Mrs C. Laignel, FI-DI, tel. 73722.

  6. A new neutron time-of-flight detector to measure the MeV neutron spectrum at the National Ignition Facility

    International Nuclear Information System (INIS)

    A new time-of-flight detector has been developed to measure the neutron spectrum at the National Ignition Facility. This detector allows for a more accurate measurement of the down scattered neutrons as well as the determination of the TT neutron spectrum. First measurements with this detector are being presented. (author)

  7. Measuring neutron energy spectra of 252Cf and Am-Be source with neutron time-of-flight spectrometer with double scintillators

    International Nuclear Information System (INIS)

    We established a neutron time-of-flight spectrometer with double scintillators. It can be used to measure the energy spectra of neutron sources. It is capable of working at above several hundred keV. We measured the energy spectra of 252Cf and Am-Be neutron sources by using this spectrometer. The results obtained were compared to those in other works

  8. Real time neutronic evolution CNE (Embalse nuclear power plant)

    International Nuclear Information System (INIS)

    The simulator of the Embalse nuclear power plant uses a Point Reactor Model(PRM) for the neutronic evolution calculation. As this model is not conservative for transients produced by the sudden or localized reactivity insertion in big cores, it is convenient to use spatial models in these cases. In this report we show the results obtained using a nodal model (codes NODOS-TIEMPO). This model has been fitted against a more exact solution for the neutron flux and delayed neutron precursors. This has been done for the reactor at full power with nominal values for the reactivity control devices (liquid zones and adjusters rods). Transients corresponding to the global variation of the liquid zones and to the insertion of fresh fuel in some channels are shown. The results are compared with calculations made with the quasi-static model of the PUMA code. (author). 1 ref

  9. Current status and future prospect of space and time reversal symmetry violation on low energy neutron reactions

    International Nuclear Information System (INIS)

    In this report, the papers on symmetry violation under space reflection and time reversal and neutron spin, neutron spin rotation and P-violation, parity nonconservation in neutron capture reaction, some advantage of the search for CP-violation in neutron scattering, dynamic polarization of 139La target, alexandrite laser for optical pumping, polarized 3He system for T- and P-violation neutron experiments, control of neutron spin in T-violation neutron experiment, symmetry regarding time and space and angular distribution and angular correlation of radiation and particle beams, T-violation due to low temperature nuclear polarization and axion exploration using nuclear transition are collected. (K.I.)

  10. Time-of-flight measurement of fast neutrons with Timepix detectors

    Science.gov (United States)

    Bergmann, B.; Nelson, R. O.; O'Donnell, J. M.; Pospisil, S.; Solc, J.; Takai, H.; Vykydal, Z.

    2014-05-01

    Timepix pixel detectors have been used to study the response of silicon hybrid pixel detectors to fast neutrons from a pulsed neutron beam at WNR FP30R, a 14 m long flight path, in the Los Alamos Neutron Science Center. Neutrons with kinetic energies up to 600 MeV were available. In order to enhance the conversion of neutrons to energetic charged particles, several converter foils and filters were attached to the 300 μm thick silicon sensor, i.e. polyethylene, polyethylene with aluminum, 6LiF, 6LiF with aluminum, aluminum. The Time-of-Arrival mode of the Timepix detectors has permitted the application of the Time-of-Flight (TOF) technique for the assignment of the detected interactions in the form of clusters (groups of adjacent pixels) in the pixel matrix, to the kinetic energies of the incident neutrons. It was found that, for lower neutron energies ( ~ MeV range) the cluster rates below the polyethylene and the polyethylene and aluminum region, produced by recoil protons, are a good measure for the mean kinetic energies of neutrons. For energies above 50 MeV nuclear reactions in the silicon dominate the detector response. In this energy range the shape of the clusters indicates the neutron kinetic energy.

  11. Parameters Affecting Temporal Resolution of Time Resolved Integrative Optical Neutron Detector (TRION)

    CERN Document Server

    Mor, I; Dangendorf, V; Bar, D; Feldman, G; Goldberg, M B; Tittelmeier, K; Bromberger, B; Brandis, M; Weierganz, M

    2013-01-01

    The Time-Resolved Integrative Optical Neutron (TRION) detector was developed for Fast Neutron Resonance Radiography (FNRR), a fast-neutron transmission imaging method that exploits characteristic energy-variations of the total scattering cross-section in the En = 1-10 MeV range to detect specific elements within a radiographed object. As opposed to classical event-counting time of flight (ECTOF), it integrates the detector signal during a well-defined neutron Time of Flight window corresponding to a pre-selected energy bin, e.g., the energy-interval spanning a cross-section resonance of an element such as C, O and N. The integrative characteristic of the detector permits loss-free operation at very intense, pulsed neutron fluxes, at a cost however, of recorded temporal resolution degradation. This work presents a theoretical and experimental evaluation of detector related parameters which affect temporal resolution of the TRION system.

  12. Parameters affecting temporal resolution of Time Resolved Integrative Optical Neutron Detector (TRION)

    Science.gov (United States)

    Mor, I.; Vartsky, D.; Dangendorf, V.; Bar, D.; Feldman, G.; Goldberg, M. B.; Tittelmeier, K.; Bromberger, B.; Brandis, M.; Weierganz, M.

    2013-11-01

    The Time-Resolved Integrative Optical Neutron (TRION) detector was developed for Fast Neutron Resonance Radiography (FNRR), a fast-neutron transmission imaging method that exploits characteristic energy-variations of the total scattering cross-section in the En = 1-10 MeV range to detect specific elements within a radiographed object. As opposed to classical event-counting time of flight (ECTOF), it integrates the detector signal during a well-defined neutron Time of Flight window corresponding to a pre-selected energy bin, e.g., the energy-interval spanning a cross-section resonance of an element such as C, O and N. The integrative characteristic of the detector permits loss-free operation at very intense, pulsed neutron fluxes, at a cost however, of recorded temporal resolution degradation This work presents a theoretical and experimental evaluation of detector related parameters which affect temporal resolution of the TRION system.

  13. Calibration and operation of a neutron time-of-flight scintillator array on Nova

    International Nuclear Information System (INIS)

    The Tion diagnostic is a 1020-channel scintillator array on the Nova laser at Livermore. It measures the arrival time of single D-D or D-T neutrons at 27 m from the target with time resolution of 4 ns. The effect of neutron scattering has been obtained from Monte-Carlo neutron transport simulations and the scattered response is convolved with a Gaussian source to fit the data. The data analysis has been checked using targets which produce roughly equal numbers of D-T and D-D counts. The temperature obtained from Tion and from a current-mode neutron time-of-flight detector are in agreement for neutron yields above 1 x 109. (orig.)

  14. Neutron production and time resolution of a new class moderator for pulsed neutron diffraction. Measurements and transport calculations

    International Nuclear Information System (INIS)

    Measurements of neutron pulse time-width and intensity have been carried out on grids of small moderators placed side by side and decoupled by cadmium strips; a moderator concept introduced by the authors through previous publications. Transport calculations are based on the standard reactor code DOT 3.5 with the ENDF-B IV nuclear data library. (orig.)

  15. Proceedings of the 1986 workshop on advanced time-of-flight neutron powder diffraction

    International Nuclear Information System (INIS)

    This report contains abstracts of talks and summaries of discussions from a small workshop held to discuss the future of time-of-flight neutron powder diffraction and its implementation at the Los Alamos Neutron Scattering Center. 47 refs., 3 figs

  16. Detection of buried explosives using portable neutron sources with nanosecond timing

    Energy Technology Data Exchange (ETDEWEB)

    Kuznetsov, A.V. E-mail: apl@atom.nw.ru; Evsenin, A.V.; Gorshkov, I.Yu.; Osetrov, O.I.; Vakhtin, D.N

    2004-07-01

    Significant reduction of time needed to identify hidden explosives and other hazardous materials by the 'neutron in, gamma out' method has been achieved by introducing timed (nanosecond) neutron sources--the so-called nanosecond neutron analysis technique. Prototype mobile device for explosives' detection based on a timed (nanosecond) isotopic {sup 252}Cf neutron source has been created. The prototype is capable of identifying 400 g of hidden explosives in 10 min. Tests have been also made with a prototype device using timed (nanosecond) neutron source based on a portable D-T neutron generator with built-in segmented detector of accompanying {alpha}-particles. The presently achieved intensity of the neutron generator is 5x10{sup 7} n/s into 4{pi}, with over 10{sup 6} of these neutrons being correlated with {alpha}-particles detected by the built-in {alpha}-particle detector. Results of measurements with an anti-personnel landmine imitator are presented.

  17. FOCUS: neutron time-of-flight spectrometer at SINQ: recent progress

    Energy Technology Data Exchange (ETDEWEB)

    Janssen, S.; Mesot, J.; Holitzner, L. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Hempelmann, R. [Saarbruecken Univ. (Germany)

    1997-09-01

    At the Swiss neutron spallation source SINQ a time-of-flight spectrometer for cold neutrons is under construction. The design foresees a Hybrid solution combining a Fermi chopper with a doubly focusing crystal monochromator. During 1996 important progress has been made concerning the main spectrometer components such as the spectrometer housing and the detector system. (author) 2 figs., 3 refs.

  18. Mass of Neutron Star in SdS space-time

    CERN Document Server

    Vinayaraj O K

    2008-01-01

    In this work we present a modified TOV equation which incorporates the cosmological constant with regard to the recent astronomical observations that the Universe is in a phase of accelerated expansion. Using this modified TOV equation we considered the structure of a neutron star in SdS space-time and calculated maximum mass limit for neutron stars.

  19. A time-dependent neutron transport method of characteristics formulation with time derivative propagation

    Science.gov (United States)

    Hoffman, Adam J.; Lee, John C.

    2016-02-01

    A new time-dependent Method of Characteristics (MOC) formulation for nuclear reactor kinetics was developed utilizing angular flux time-derivative propagation. This method avoids the requirement of storing the angular flux at previous points in time to represent a discretized time derivative; instead, an equation for the angular flux time derivative along 1D spatial characteristics is derived and solved concurrently with the 1D transport characteristic equation. This approach allows the angular flux time derivative to be recast principally in terms of the neutron source time derivatives, which are approximated to high-order accuracy using the backward differentiation formula (BDF). This approach, called Source Derivative Propagation (SDP), drastically reduces the memory requirements of time-dependent MOC relative to methods that require storing the angular flux. An SDP method was developed for 2D and 3D applications and implemented in the computer code DeCART in 2D. DeCART was used to model two reactor transient benchmarks: a modified TWIGL problem and a C5G7 transient. The SDP method accurately and efficiently replicated the solution of the conventional time-dependent MOC method using two orders of magnitude less memory.

  20. Progress in space-charge limited machines: Four times the design intensity in the CERN Proton Synchrotron Booster

    International Nuclear Information System (INIS)

    Starting from rather modes performances, the CERN Proton Synchrotron Booster has now reached its sum-of-four-rings design intensity of 1013 protons per pulse in each ring, featuring the outstanding maximum space-charge tune shift of 0.6 units. The latter requires dynamic compensation of half and (even systematic) third integer stopbands. More measures were introduced to push the intensity ceiling higher: careful choice of working area, controlled linear coupling to enhance injection efficiency and to fill the full aperture with a better-suited transverse charge distribution; bunch shaping by addition of a second-harmonic RF system, beam loading compensated by fast feedback; RF feedforward in the fundamental cavities; feedback systems taming longitudinal coupled-bunch instabilities, and transverse wide-band dampers replacing octupoles previously used. The article reviews these techniques as well as some of the Booster's unique beam diagnostics, crucial to the achievement of these performances

  1. CERN GSM monitoring system

    CERN Multimedia

    Ghabrous Larrea, C

    2009-01-01

    As a result of the tremendous development of GSM services over the last years, the number of related services used by organizations has drastically increased. Therefore, monitoring GSM services is becoming a business critical issue in order to be able to react appropriately in case of incident. In order to provide with GSM coverage all the CERN underground facilities, more than 50 km of leaky feeder cable have been deployed. This infrastructure is also used to propagate VHF radio signals for the CERN’s fire brigade. Even though CERN’s mobile operator monitors the network, it cannot guarantee the availability of GSM services, and for sure not VHF services, where signals are carried by the leaky feeder cable. So, a global monitoring system has become critical to CERN. In addition, monitoring this infrastructure will allow to characterize its behaviour over time, especially with LHC operation. Given that commercial solutions were not yet mature, CERN developed a system based on GSM probes and an application...

  2. CERN, accelerator of motivation

    CERN Multimedia

    François Becler

    2014-01-01

    Have your dreams ever come true? My dream did, when I was lucky enough to be allowed into the world’s largest particle physics laboratory and spend five whole days there.   François, in front of LEP's DELPHI detector, displayed in the LHCb cavern. François was given the opportunity to visit the experiment during his placement at CERN. I’m a pupil in my last year at the Collège Jean-Jacques Rousseau in Saint-Julien-en-Genevois and was on a work experience placement at CERN from 16 to 20 December last year. I’m so happy I was chosen because working alongside physicists and engineers of all nationalities was like a dream come true. The first thing that impressed me was the size of the site, its infrastructures and facilities but also the fact that I was working in a prestigious, world-renowned organisation. I spent lots of time looking at the map and trying to find my way around... CERN's such a massive place ! Th...

  3. The N-TOF Facility at CERN: Status and Perspectives

    International Nuclear Information System (INIS)

    The outstanding features of the existing CERN n-TOF neutron beam are the very high instantaneous neutron flux, excellent n-TOF resolution, low intrinsic backgrounds and coverage of a wide range of neutron energies, from thermal to a few GeV. These characteristics provide a unique possibility to perform neutron-induced cross-section and angular distribution measurements for applications such as nuclear astrophysics, nuclear reactor technology and basic nuclear physics. This paper presents in detail all the characteristics of the present neutron beam in the different available configurations, which correspond to two different collimation systems and two choices of neutron moderator. The features include shape and intensity of the neutron flux, beam spatial profile, in-beam background components and the energy resolution broadening. The description of these features is based upon both dedicated measurements as well as Monte Carlo simulations, and includes an estimation of the systematic uncertainties in the mentioned quantities. The overall efficiency of the experimental program and the range of possible measurements will be expanded in the near future with the construction of a second experimental area (EAR-2), vertically located 20 m on top of the present n-TOF spallation target. This upgrade, which will benefit from a neutron flux 25 times higher than the existing one, will provide a substantial improvement in measurement sensitivities and will open the possibility to measure neutron cross-section of isotopes with very short half-lives or available in very small quantities. The technical study for the construction of this new neutron beam will be presented, highlighting the main advantages compared to the presently existing Experimental Area (EAR-1). (author)

  4. Pulse processing routines for neutron time-of-flight data

    CERN Document Server

    Žugec, P; Guerrero, C; Gunsing, F; Vlachoudis, V; Sabate-Gilarte, M; Stamatopoulos, A; Wright, T; Lerendegui-Marco, J; Mingrone, F; Ryan, J A; Warren, S G; Tsinganis, A; Barbagallo, M

    2016-01-01

    A pulse shape analysis framework is described, which was developed for n_TOF-Phase3, the third phase in the operation of the n_TOF facility at CERN. The most notable feature of this new framework is the adoption of generic pulse shape analysis routines, characterized by a minimal number of explicit assumptions about the nature of pulses. The aim of these routines is to be applicable to a wide variety of detectors, thus facilitating the introduction of the new detectors or types of detectors into the analysis framework. The operational details of the routines are suited to the specific requirements of particular detectors by adjusting the set of external input parameters. Pulse recognition, baseline calculation and the pulse shape fitting procedure are described. Special emphasis is put on their computational efficiency, since the most basic implementations of these conceptually simple methods are often computationally inefficient.

  5. Pulse processing routines for neutron time-of-flight data

    Science.gov (United States)

    Žugec, P.; Weiß, C.; Guerrero, C.; Gunsing, F.; Vlachoudis, V.; Sabate-Gilarte, M.; Stamatopoulos, A.; Wright, T.; Lerendegui-Marco, J.; Mingrone, F.; Ryan, J. A.; Warren, S. G.; Tsinganis, A.; Barbagallo, M.

    2016-03-01

    A pulse shape analysis framework is described, which was developed for n_TOF-Phase3, the third phase in the operation of the n_TOF facility at CERN. The most notable feature of this new framework is the adoption of generic pulse shape analysis routines, characterized by a minimal number of explicit assumptions about the nature of pulses. The aim of these routines is to be applicable to a wide variety of detectors, thus facilitating the introduction of the new detectors or types of detectors into the analysis framework. The operational details of the routines are suited to the specific requirements of particular detectors by adjusting the set of external input parameters. Pulse recognition, baseline calculation and the pulse shape fitting procedure are described. Special emphasis is put on their computational efficiency, since the most basic implementations of these conceptually simple methods are often computationally inefficient.

  6. Time reversal in polarized neutron decay: the emiT experiment

    CERN Document Server

    Jones, G L; Anaya, J M; Bowles, T J; Chupp, T E; Coulter, K P; Dewey, M S; Freedman, S J; Fujikawa, B K; García, A; Greene, G L; Hwang, S R; Lising, L J; Mumm, H P; Nico, J S; Robertson, R G H; Steiger, T D; Teasdale, W A; Thompson, A K; Wasserman, E G; Wietfeldt, F E; Wilkerson, J F

    2000-01-01

    The standard electro-weak model predicts negligible violation of time-reversal invariance in light quark processes. We report on an experimental test of time-reversal invariance in the beta decay of polarized neutrons as a search for physics beyond the standard model. The emiT collaboration has measured the time-reversal-violating triple-correlation in neutron beta decay between the neutron spin, electron momentum, and neutrino momentum often referred to as the D coefficient. The first run of the experiment produced 14 million events which are currently being analyzed. However, a second run with improved detectors should provide greater statistical precision and reduced systematic uncertainties.

  7. Time reversal in polarized neutron decay: the emiT experiment

    International Nuclear Information System (INIS)

    The standard electro-weak model predicts negligible violation of time-reversal invariance in light quark processes. We report on an experimental test of time-reversal invariance in the beta decay of polarized neutrons as a search for physics beyond the standard model. The emiT collaboration has measured the time-reversal-violating triple-correlation in neutron beta decay between the neutron spin, electron momentum, and neutrino momentum often referred to as the D coefficient. The first run of the experiment produced 14 million events which are currently being analyzed. However, a second run with improved detectors should provide greater statistical precision and reduced systematic uncertainties

  8. Fusion neutron detector for time-of-flight measurements in z-pinch and plasma focus experiments.

    Science.gov (United States)

    Klir, D; Kravarik, J; Kubes, P; Rezac, K; Litseva, E; Tomaszewski, K; Karpinski, L; Paduch, M; Scholz, M

    2011-03-01

    We have developed and tested sensitive neutron detectors for neutron time-of-flight measurements in z-pinch and plasma focus experiments with neutron emission times in tens of nanoseconds and with neutron yields between 10(6) and 10(12) per one shot. The neutron detectors are composed of a BC-408 fast plastic scintillator and Hamamatsu H1949-51 photomultiplier tube (PMT). During the calibration procedure, a PMT delay was determined for various operating voltages. The temporal resolution of the neutron detector was measured for the most commonly used PMT voltage of 1.4 kV. At the PF-1000 plasma focus, a novel method of the acquisition of a pulse height distribution has been used. This pulse height analysis enabled to determine the single neutron sensitivity for various neutron energies and to calibrate the neutron detector for absolute neutron yields at about 2.45 MeV. PMID:21456735

  9. Fusion neutron detector for time-of-flight measurements in z-pinch and plasma focus experiments

    International Nuclear Information System (INIS)

    We have developed and tested sensitive neutron detectors for neutron time-of-flight measurements in z-pinch and plasma focus experiments with neutron emission times in tens of nanoseconds and with neutron yields between 106 and 1012 per one shot. The neutron detectors are composed of a BC-408 fast plastic scintillator and Hamamatsu H1949-51 photomultiplier tube (PMT). During the calibration procedure, a PMT delay was determined for various operating voltages. The temporal resolution of the neutron detector was measured for the most commonly used PMT voltage of 1.4 kV. At the PF-1000 plasma focus, a novel method of the acquisition of a pulse height distribution has been used. This pulse height analysis enabled to determine the single neutron sensitivity for various neutron energies and to calibrate the neutron detector for absolute neutron yields at about 2.45 MeV.

  10. Time-frequency feature analysis and recognition of fission neutrons signal based on support vector machine

    International Nuclear Information System (INIS)

    Based on the interdependent relationship between fission neutrons (252Cf) and fission chain (235U system), the paper presents the time-frequency feature analysis and recognition in fission neutron signal based on support vector machine (SVM) through the analysis on signal characteristics and the measuring principle of the 252Cf fission neutron signal. The time-frequency characteristics and energy features of the fission neutron signal are extracted by using wavelet decomposition and de-noising wavelet packet decomposition, and then applied to training and classification by means of support vector machine based on statistical learning theory. The results show that, it is effective to obtain features of nuclear signal via wavelet decomposition and de-noising wavelet packet decomposition, and the latter can reflect the internal characteristics of the fission neutron system better. With the training accomplished, the SVM classifier achieves an accuracy rate above 70%, overcoming the lack of training samples, and verifying the effectiveness of the algorithm. (authors)

  11. MR-ToF isobar separation for mass and life-time measurements of neutron-rich zinc at ISOLTRAP

    Energy Technology Data Exchange (ETDEWEB)

    Audi, Georges; Lunney, David; Wang, Meng [CSNSMIN2P3-CNRS, Universite de Paris Sud, Orsay (France); Beck, Dietrich; Herfurth, Frank; Kluge, Juergen; Ramirez, Enrique Minaya; Neidherr, Dennis [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Blaum, Klaus; Boehm, Christine; Borgmann, Christopher; Cakirli, R. Burcu; Eliseev, Sergey [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Breitenfeldt, Martin [Leuven Univ. (Belgium). Inst. voor Kern- en Stralingsfysika; Cocolios, Thomas Elias; Kowalska, Magdalena [CERN, Geneva (Switzerland); George, Sebastian; Schwarz, Stefan [NSCL, Michigan State University, East Lansing, MI (United States); Herlert, Alexander [FAIR GmbH, Darmstadt (Germany); Kreim, Susanne [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); CERN, Geneva (Switzerland); Naimi, Sarah [RIKEN Research Facility (Japan); Rosenbusch, Marco; Schweikhard, Lutz; Wienholtz, Frank; Wolf, Robert N. [Ernst-Moritz-Arndt-Universitaet, Greifswald (Germany); Stanja, Juliane; Zuber, Kai [Technische Universitaet, Dresden (Germany)

    2012-07-01

    High-precision Penning-trap mass measurements of short-lived nuclei are performed with ISOLTRAP at the on-line isotope separator ISOLDE/CERN. An important prerequisite to achieve relative uncertainties of {delta}m/m=10{sup -8} is the availability of purely isobaric ion ensembles. To enhance the purity of radioactive ion beams, a multi-reflection time-of-flight mass separator developed at the University of Greifswald has recently been implemented at the ISOLTRAP setup. A mass resolving power of R=2.10{sup 5} and a contaminant reduction of four orders of magnitude by use of a Bradbury-Nielsen ion gate have been achieved. The performance of the combined setup (including an RFQ ion buncher, the MR-ToF MS and the two Penning traps) in both offline tests as well as in first applications with radioactive ion beams is presented. Furthermore, the physics case and recent results of mass measurements of neutron-rich Zinc are shown.

  12. MR-ToF isobar separation for mass and life-time measurements of neutron-rich zinc at ISOLTRAP

    International Nuclear Information System (INIS)

    High-precision Penning-trap mass measurements of short-lived nuclei are performed with ISOLTRAP at the on-line isotope separator ISOLDE/CERN. An important prerequisite to achieve relative uncertainties of δm/m=10-8 is the availability of purely isobaric ion ensembles. To enhance the purity of radioactive ion beams, a multi-reflection time-of-flight mass separator developed at the University of Greifswald has recently been implemented at the ISOLTRAP setup. A mass resolving power of R=2.105 and a contaminant reduction of four orders of magnitude by use of a Bradbury-Nielsen ion gate have been achieved. The performance of the combined setup (including an RFQ ion buncher, the MR-ToF MS and the two Penning traps) in both offline tests as well as in first applications with radioactive ion beams is presented. Furthermore, the physics case and recent results of mass measurements of neutron-rich Zinc are shown.

  13. Spallation Neutrons Used for Imaging in the Time and Energy Domain

    International Nuclear Information System (INIS)

    SINQ, the Swiss national source for neutron research, is based on the principle of spallation, where protons from a 590 MeV cyclotron are sent to a lead target with highest possible beam intensity. The proton beam current from the PSI’s cyclotron is of the order of 2 mA, corresponding to about 1 MW deposited beam power in the target region. SINQ is a large scale user facility. The spallation neutrons with initial energies of up to 100 MeV are slowed to thermal energies within the moderator tank filled with heavy water (D2O). Further reduction of the neutron energy can take place in the cold source, which is operated at about 25 K and is filled with liquid deuterium. Unlike similar spallation sources (SNS, Oak Ridge, United States of America; JPARC, Tokai, Japan; ISIS, Didcot, United Kingdom), SINQ is not a pulsed source but provides a constant neutron flux level. As such, it compares to a research reactor with about 15 MW of thermal power. Neutron imaging as an advanced technique for neutron research, applied studies and industrial testing is established at SINQ with two beamlines: NEUTRA for thermal neutrons and ICON for cold neutrons. This capability has only minor representation compared to the scattering facilities at SINQ, with about 15 such installations. Modern neutron imaging techniques are exclusively based on digital systems, where each pixel can be considered an individual neutron counter. Neutron imaging experiments are mainly performed in transmission mode where the comparison between the initial and transmitted radiation is used to describe the properties of the sample material in the beam. For standard applications, the full incident neutron spectrum is used, which delivers an energy average attenuation value. Recent developments at the SINQ imaging beamlines permit time dependent investigations, in particular of cyclic processes, with frames in the millisecond range. This option is of high interest for studying the injection of fuel into running

  14. Thermalization time in a model of neutron star

    Czech Academy of Sciences Publication Activity Database

    Ducomet, B.; Nečasová, Šárka

    2011-01-01

    Roč. 16, č. 3 (2011), s. 801-818. ISSN 1531-3492 R&D Projects: GA ČR GA201/08/0012 Institutional research plan: CEZ:AV0Z10190503 Keywords : comressible * heat conducting fluids * one-dimensional symmetry * neutron star Subject RIV: BA - General Mathematics Impact factor: 0.921, year: 2011 http://aimsciences.org/journals/displayArticlesnew.jsp?paperID=6325

  15. Maintenance work on CERN mobile phone services

    CERN Multimedia

    2007-01-01

    Maintenance work on the CERN GSM services will be carried out by our mobile operator, Sunrise, from 8.00 p.m. on 25 June to 1 a.m. on 26 June. External calls from CERN mobile phones using the 333 prefix may be disrupted for 30 minutes during this time. Other type of calls, e.g. mobile to mobile or mobile to CERN fixed phones, will not be affected. Should you have any questions regarding this maintenance operation, please contact the switchboard by phone (76111) or e-mail (standard.telephone@cern.ch) Telecom Section IT/CS

  16. MCT: a Monte Carlo code for time-dependent neutron thermalization problems

    International Nuclear Information System (INIS)

    In the Monte Carlo simulation of pulse source experiments, the neutron energy spectrum, spatial distribution and total density may be required for a long time after the pulse. If the assemblies are very small, as often occurs in the cases of interest, sophisticated Monte Carlo techniques must be applied which force neutrons to remain in the system during the time interval investigated. In the MCT code a splitting technique has been applied to neutrons exceeding assigned target times, and we have found that this technique compares very favorably with more usual ones, such as the expected leakage probability, giving large gains in computational time and variance. As an example, satisfactory asymptotic thermal spectra with a neutron attenuation of 10-5 were quickly obtained. (U.S.)

  17. Time-resolved Neutron-gamma-ray Data Acquisition for in Situ Subsurface Planetary Geochemistry

    Science.gov (United States)

    Bodnarik, Julie G.; Burger, Dan Michael; Burger, A.; Evans, L. G.; Parsons, A. M.; Schweitzer, J. S.; Starr R. D.; Stassun, K. G.

    2013-01-01

    The current gamma-ray/neutron instrumentation development effort at NASA Goddard Space Flight Center aims to extend the use of active pulsed neutron interrogation techniques to probe the subsurface elemental composition of planetary bodies in situ. Previous NASA planetary science missions, that used neutron and/or gamma-ray spectroscopy instruments, have relied on neutrons produced from galactic cosmic rays. One of the distinguishing features of this effort is the inclusion of a high intensity 14.1 MeV pulsed neutron generator synchronized with a custom data acquisition system to time each event relative to the pulse. With usually only one opportunity to collect data, it is difficult to set a priori time-gating windows to obtain the best possible results. Acquiring time-tagged, event-by-event data from nuclear induced reactions provides raw data sets containing channel/energy, and event time for each gamma ray or neutron detected. The resulting data set can be plotted as a function of time or energy using optimized analysis windows after the data are acquired. Time windows can now be chosen to produce energy spectra that yield the most statistically significant and accurate elemental composition results that can be derived from the complete data set. The advantages of post-processing gamma-ray time-tagged event-by-event data in experimental tests using our prototype instrument will be demonstrated.

  18. Development of a new time-amplitude converter with tunnel diodes for improving fast neutron spectrometry by time of flight

    International Nuclear Information System (INIS)

    New time-amplitude converter with Esaki diodes, the events being preselected before analysis, allows for realizing a fast neutron spectrometer by time-of-flight with an 1.5 * 10-9 s overall time resolution for 12C (n,n') at 14 MeV. (author)

  19. Application of neutron time-of-flight diffraction to texture studies

    International Nuclear Information System (INIS)

    The application of neutron time-of-flight diffraction to texture investigation on polycrystalline solids is described. A composition with the stationary method shows the efficiency but also some disadvantages of the proposed technique. The texture diffractometer NSWR is described, which was going into operation at the pulsed reactor IBR-2. Selected experiments on metallic and geological specimens demonstrate the efficiency of neutron texture analysis using time-of-flight technique

  20. Hangout with CERN: Welcome to CERN (S01E01)

    CERN Multimedia

    Kahle, Kate

    2012-01-01

    In this first Hangout with CERN "Welcome to CERN" ATLAS physicist Steven Goldfarb, CERN theorist Alvaro De Rujula and Mick Storr from the CERN education group introduce CERN and answer some of the questions received via #askCERN on Twitter and Google+. Recorded live on 1st November 2012.

  1. Time-of-flight diffraction at pulsed neutron sources: An introduction to the symposium

    International Nuclear Information System (INIS)

    In the 25 years since the first low-power demonstration experiments, pulsed neutron sources have become as productive as reactor sources for many types of diffraction experiments. The pulsed neutron sources presently operating in the United States, England, and Japan offer state of the art instruments for powder and single crystal diffraction, small angle scattering, and such specialized techniques as grazing-incidence neutron reflection, as well as quasielastic and inelastic scattering. In this symposium, speakers review the latest advances in diffraction instrumentation for pulsed neutron sources and give examples of some of the important science presently being done. In this introduction to the symposium, I briefly define the basic principles of pulsed neutron sources, review their development, comment in general terms on the development of time-of-flight diffraction instrumentation for these sources, and project how this field will develop in the next ten years

  2. Invited Article: Polarization ``Down Under'': The polarized time-of-flight neutron reflectometer PLATYPUS

    Science.gov (United States)

    Saerbeck, T.; Klose, F.; Le Brun, A. P.; Füzi, J.; Brule, A.; Nelson, A.; Holt, S. A.; James, M.

    2012-08-01

    This review presents the implementation and full characterization of the polarization equipment of the time-of-flight neutron reflectometer PLATYPUS at the Australian Nuclear Science and Technology Organisation (ANSTO). The functionality and efficiency of individual components are evaluated and found to maintain a high neutron beam polarization with a maximum of 99.3% through polarizing Fe/Si supermirrors. Neutron spin-flippers with efficiencies of 99.7% give full control over the incident and scattered neutron spin direction over the whole wavelength spectrum available in the instrument. The first scientific experiments illustrate data correction mechanisms for finite polarizations and reveal an extraordinarily high reproducibility for measuring magnetic thin film samples. The setup is now fully commissioned and available for users through the neutron beam proposal system of the Bragg Institute at ANSTO.

  3. Fast neutron flux analyzer with real-time digital pulse shape discrimination

    Science.gov (United States)

    Ivanova, A. A.; Zubarev, P. V.; Ivanenko, S. V.; Khilchenko, A. D.; Kotelnikov, A. I.; Polosatkin, S. V.; Puryga, E. A.; Shvyrev, V. G.; Sulyaev, Yu. S.

    2016-08-01

    Investigation of subthermonuclear plasma confinement and heating in magnetic fusion devices such as GOL-3 and GDT at the Budker Institute (Novosibirsk, Russia) requires sophisticated equipment for neutron-, gamma- diagnostics and upgrading data acquisition systems with online data processing. Measurement of fast neutron flux with stilbene scintillation detectors raised the problem of discrimination of the neutrons (n) from background cosmic particles (muons) and neutron-induced gamma rays (γ). This paper describes a fast neutron flux analyzer with real-time digital pulse-shape discrimination (DPSD) algorithm FPGA-implemented for the GOL-3 and GDT devices. This analyzer was tested and calibrated with the help of 137Cs and 252Cf radiation sources. The Figures of Merit (FOM) calculated for different energy cuts are presented.

  4. Virgin Galactic explores CERN

    CERN Multimedia

    2016-01-01

    Virgin Galactic visited CERN with a group of future astronauts and Sir Richard Branson. During their visit the group was shown around various experiments, including the Globe, SM18, AMS and the CERN Control Centre.

  5. Doing business with CERN

    CERN Multimedia

    2015-01-01

    The Procurement Service, in collaboration with the Communications group’s Design team, has recently launched a new information campaign targeted at companies wishing to supply their products and services to CERN. This campaign comprises:   A brochure, available in hard and soft copy:  http://procurement.web.cern.ch/brochures/doing-business-with-cern.   A 6-minute video overview: https://procurement-dev.web.cern.ch/doing-business-with-cern. This campaign is intended for Member State firms with whom CERN is yet to do business. The key objectives are: To emphasise that CERN can be considered a major customer across a wide range of activities;   To present CERN’s procurement procedures in a dynamic and digestible way;   To highlight the information available on CERN’s procurement website: http://procurement.web.cern.ch. Furthermore, a new section called “Having a contract with CERN” is also now ava...

  6. CERN Shop Christmas Sale

    CERN Multimedia

    Visits & Exhibition Service/ETT-VE

    2001-01-01

    11-13.12.2001 Looking for Christmas present ideas? Come to the Reception Shop Special Stand in Meyrin, Main Building, ground floor, from Tuesday 11 to Thursday 13 December from 10.30 to 16.00. CERN Calendar 10.- CERN Sweat-shirts(M, L, XL) 30.- CERN T-shirt (M, L, XL) 20.- New CERN silk tie (2 colours) 35.- Fancy silk tie (blue, bordeau) 25.- Silk scarf (light blue, red, yellow) 35.- Swiss army knife with CERN logo 25.- CERN watch 25.- CERN baseball cap 15.- CERN briefcase 15.- Book 'Antimatter' (English) 35.- Book 'How the web was born' (English) 25.- The Search for Infinity (French, Italian, English, German) 40.-   If you miss this special occasion, the articles are also available at the Reception Shop in Building 33 from Monday to Saturday between 08.30 and 17.30 hrs.

  7. Greece at CERN

    CERN Multimedia

    CERN Press Office. Geneva

    1997-01-01

    Greece, one of CERN*'s founding Member States, inaugurated its first Industrial Exhibition at the Meyrin site on Tuesday, 14 October. After a meeting with CERN's Director General, Professor Christopher Llewellyn Smith, Professor Emmanuel Frangoulis, the General Secretary of the Greek Ministry of Industry, accompanied by Prof Emmanuel Floratos, Greek delegate to CERN council visited the DELPHI experiment on the LEP collider, guided by Andromachi Tsirou, a Greek physicist.

  8. France at CERN

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    Rolf Heuer, CERN Director General, visits the exhibition "La France au CERN". The exhibition France at CERN, organized by UBIFRANCE in collaboration with CERN's GS/SEM (Site Engineering and Management) service, took place from Monday 7 to Wednesday 9 June in the Main Building. The 36 French firms taking part came to present their products and technologies related to the Organization's activities. The next exhibition will be "Netherlands at CERN" in November.

  9. Spotlight on CERN

    CERN Multimedia

    CERN video productions

    2009-01-01

    Welcome to the Globe of Science and Innovation for the first "Spotlight on CERN" just a few weeks before the restart of the LHC machine. Today our guest is Mike Lamont, who is in charge of the Operations Group for the accelerator beams. This weekend, protons were injected into the LHC for the first time since September 2008. But before we talk about that, let's go back a few weeks and look at the previous stage, which involved testing the transfer lines of the injection tunnels TI2/TI8. Our video team was there to film this operation.

  10. A time-of-flight neutron spectrometer for DT-plasma diagnostics

    International Nuclear Information System (INIS)

    A neutron time-of-flight spectrometer is proposed for spectral measurements of 14 MeV neutrons, generated in deuterium plasma through consecutive d(d,t)p and d(t,n)α reactions, i.e. minority d-t neutrons. According to numerical simulations, spectral width, average energy and fluxes of neutrons depend on confinement and slowing down of the tritons in which the electron temperature plays a significant role. Neutrons, backscattered in a deuterated first scintillator are detected in a second hydrogen based scintillator. Laboratory tests, with an efficiency of 8 x 10-6 cm2 provide a resolution equal to 2.2%, which scales reciprocally to the flight path length. A reference spectrometer is suggested for measurements at JET, with an efficiency of 2.7 x 10-2 cm2 and an energy resolution better than 3%, which enables spectral measurements of 14 MeV minority neutrons in the emission interval 5 x 1013 - 1016 s-1, provided neutron filters are utilized. An upgraded version of the device, aimed for spectral measurements of 14 MeV neutrons from DT-plasmas, is suggested. In this case the resolution is 2.0% and the maximum efficiency 2.9 x 10-3 cm2. (au)

  11. Time-of-flight neutron detection using PECVD grown boron carbide diode detector

    International Nuclear Information System (INIS)

    The development of novel neutron detectors requires an understanding of the entire neutron detection process, a process which depends strongly on material properties. Here we present accurate measurements of the neutron detection efficiency of an unenriched 640 nm thick boron carbide solid state neutron detector grown by plasma enhanced chemical vapor deposition as a function of the neutron wavelength at a time-of-flight facility. The data were compared to that obtained simultaneously by a calibrated nitrogen detector over the same wavelength range. The measured spectra of both detectors fit a Maxwell–Boltzmann wavelength distribution, thereby indicating that the boron carbide detector can be used as a reliable beam monitor. Measurements of the material properties (density, thickness and elemental composition) of the semiconducting boron carbide enable a precise calculation of the ideal expected neutron detection efficiency. The calculated neutron detection efficiency for the effective moderator temperature (obtained from a fit to the Maxwell–Boltzmann distribution) showed excellent agreement with the experimentally determined neutron detection efficiency of 1.25%. Higher efficiencies may be obtained either by increased film thickness and/or 100% 10B enrichment of the boron carbide source molecule

  12. Measurement of Compound Nucleus Space-Time Extent with Two-Neutron Correlation Functions

    International Nuclear Information System (INIS)

    Two-neutron relative-momentum correlation functions have been measured in the 130 MeV 18O+26Mg reaction. Differences in the longitudinal and transverse correlation functions, observed for the first time for neutrons, allow an independent determination of the spatial extent and the time scale for decay of the 44Ca compound nucleus. A comparison with theoretical calculations indicates a radius of 4.4±0.3 fm and an average neutron emission time scale of 1100±100 fm/c for 44Ca at 100 MeV excitation energy. Correlation functions selected by cuts on the total momentum of the neutron pair give a quantitative characterization of the cooling of a compound nucleus. copyright 1995 The American Physical Society

  13. 2008 annual CERN Road Race

    CERN Multimedia

    2008-01-01

    Dear runners, The 2008 annual CERN Road Race will be held on Wednesday 24 September at 6.00 p.m. This 5.4 km race consists of 3 laps of a 1.8 km circuit in the West Area of the Meyrin site and is open to everyone working at CERN and their families. Past races have attracted runners of all speeds, with times ranging from under 17 to over 34 minutes. The race is run on a handicap basis, with starting times staggered to ensure that (in theory) all runners finish together. However, if the popularity of the race continues to grow (95 runners took part last year), its format may be modified to a classic single start. For more information and to complete the online entry form, go to http://club-running.web.cern.ch

  14. CERN Photowalk 2015

    CERN Multimedia

    2015-01-01

    CERN is organising a Photowalk on Friday 25 September 2015. At this event a few selected photographers will get the chance to come to CERN, the European Organization for Nuclear Research, for an exclusive behind-the-scenes tour of the laboratory. For more information: http://photowalk2015.web.cern.ch/

  15. In the CERN Library

    CERN Multimedia

    1963-01-01

    Seen in this picture is Noria Christophoridou, librarian of the Greek Atomic Energy Commission, who has been sent by her government to CERN for a year to widen her experience of library and documentation services. In the photograph she is providing information to Kurt Gottfried, a CERN visiting scientist from Harvard University, who is spending a year with CERN's Theory Division

  16. Time-resolved fast-neutron pinhole camera for studying thermonuclear plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, R.W.; Weingart, R.C.

    1976-02-02

    A fast-neutron pinhole camera with high detection efficiency and nanosecond time-resolution has been developed and applied to the investigation of the spatial and temporal distributions of DD- and DT-neutrons produced by thermonuclear plasmas. The pinhole consists of a specially designed 1.15 m long copper collimator with an effective aperture of 1 mm diameter. Several different types of spatial resolution detectors have been used at the image plane: (1) a multi-element, scintillation-photomultiplier system used for time-resolved measurements consisting of sixty-one individual detectors, (2) a scintillation-fiber-chamber coupled to a gated image-intensifier tube used for direct photographing of the neutron image, and (3) a propane bubble chamber used for time-integrated recording with a capability to distinguish DD- from DT-neutrons. Pulsed neutron sources with typical dimensions of 1 cm emitting of the order of 10/sup 12/ neutrons over a time period of 10-100 nsec have been investigated. A spatial resolution of 1 mm and a time resolution of approximately 10 nsec was achieved in the investigations of dense plasma compression phenomena.

  17. CrossRef The Second Beam-Line and Experimental Area at n_TOF: A New Opportunity for Challenging Neutron Measurements at CERN

    CERN Document Server

    Colonna, Nicola; Chiaveri, Enrico

    2015-01-01

    Since 2001, a wealth of neutron capture and neutron-induced fission reactions has been measured at n_TOF, providing an important contribution to a wide variety of research fields. The experimental activity is driven mostly by two motivations: on the one hand, capture reactions are studied with the aim of improving current models of stellar nucleosynthesis of heavy elements. A review of the needs related to nuclear astrophysics and the contribution of the n_TOF program can be found in [1, 2].

  18. Upgrade of the CERN telephone exchange

    CERN Multimedia

    2006-01-01

    As part of the upgrade of telephone services, maintenance work will be carried out on the CERN switching centre between 8.00 p.m. and 10.00 p.m. on Monday 9 October. Telephone services may be disrupted and possibly even interrupted during this time. We apologise in advance for any inconvenience this may cause. CERN TELECOM Service

  19. Robert Aymar, Director-General of CERN

    CERN Multimedia

    Patrice Loïez

    2003-01-01

    Robert Aymar, photographed in 2003 before taking his position as Director-General at CERN, succeeding Luciano Maiani in 2004. At this time, Aymar was director of the International Thermonuclear Experimental Reactor (ITER) although he had already been involved with developments at CERN, chairing the External Review Committee, set up in 2001 in response to the increased cost of the LHC.

  20. Time-of-flight discrimination between gamma-rays and neutrons by using artificial neural networks

    International Nuclear Information System (INIS)

    Highlights: ► Time-of-flight (tof) is an obvious method for separation between gamma and neutron particles. ► tof distributions are obtained by neural networks. ► Neural network method is consistent with the experimental results. ► Neural networks can classify different events for discrimination. - Abstract: In gamma-ray spectroscopy, a number of neutrons are emitted from the nuclei together with the gamma-rays. These neutrons influence gamma-ray spectra. An obvious method for discrimination between neutrons and gamma-rays is based on the time-of-flight (tof) technique. In this work, the tof distributions of gamma-rays and neutrons were obtained both experimentally and by using artificial neural networks (ANNs). It was shown that, ANN can correctly classify gamma-ray and neutron events. Also, for highly nonlinear detector response for tof, we have constructed consistent empirical physical formulas (EPFs) by appropriate ANNs. These ANN–EPFs can be used to derive further physical functions which could be relevant to discrimination between gamma-rays and neutrons

  1. Current Development Status of Time-of-Flight Inelastic Neutron Spectrometer at HANARO

    International Nuclear Information System (INIS)

    As part of the Cold Neutron Research Facility (CNRF) project launched in 2003, disk chopper time-off light (DC-TOF) spectrometer was proposed for the study of slow dynamics of all condensed matter sciences, which has been increasingly proven to be invaluable information. Here we present the current status of the DC-TOF instrument development. The HANARO research reactor has started operation since 1995 and reached its full operation power of 30 MW in 2004. Three neutron scattering instruments such as HRPD, FCD and SANS have been since running for user program, both domestic and foreign researchers. Till now, however there has been no inelastic neutron spectrometer in Korea, which has deterred otherwise natural growth of an inelastic neutron scattering community. Disk chopper time-of-flight inelastic neutron spectrometer is an advanced neutron scattering instrument, which has been proven worldwide to be very versatile for both basic science and material engineering studies. Therefore, when the Korea Atomic Energy Research Institute (KAERI) started the CNRF project in 2003, it was a natural choice that it decided to build DC-TOF for the cold neutron laboratory. Day-1 instruments of the CNRF project include a DC-TOF, a cold TAS, a 40m-SANS, and two reflectometers. In this paper, we present the current design specifications of the DC-TOF at the KAERI

  2. Fast neutron measurements at the nELBE time-of-flight facility

    Directory of Open Access Journals (Sweden)

    Junghansa A. R.

    2015-01-01

    Full Text Available The compact neutron-time-of-flight facility nELBE at the superconducting electron accelerator ELBE of Helmholtz-Zentrum Dresden-Rossendorf has been rebuilt. A new enlarged experimental hall with a flight path of up to 10 m is available for neutron time-of-flight experiments in the fast energy range from about 50 keV to 10 MeV. nELBE is intended to deliver nuclear data of fast neutron nuclear interactions e.g. for the transmutation of nuclear waste and improvement of neutron physical simulations of innovative nuclear systems. The experimental programme consists of transmission measurements of neutron total cross sections, elastic and inelastic scattering cross section measurements, and neutron induced fission cross sections. The inelastic scattering to the first few excited states in 56Fe was investigated by measuring the gamma production cross section with an HPGe detector. The neutron induced fission of 242Pu was studied using fast ionisation chambers with large homogeneous actinide deposits.

  3. Calibration of Time Of Flight Detectors Using Laser-driven Neutron Source

    OpenAIRE

    Mirfayzi, S. R.; Kar, S.; H. Ahmed; Krygier, A. G.; Green, A.; Alejo, A.; Clarke, R.; Freeman, R. R.; Fuchs, J.; Jung, D.; Kleinschmidt, A.; Morrison, J. T.; Najmudin, Z.; Nakamura, H.; Norreys, P.

    2015-01-01

    Calibration of three scintillators (EJ232Q, BC422Q, and EJ410) in a time-of-flight arrangement using a laser drive-neutron source is presented. The three plastic scintillator detectors were calibrated with gamma insensitive bubble detector spectrometers, which were absolutely calibrated over a wide range of neutron energies ranging from sub-MeV to 20 MeV. A typical set of data obtained simultaneously by the detectors is shown, measuring the neutron spectrum emitted from a petawatt laser irrad...

  4. Calibration of time of flight detectors using laser-driven neutron source.

    Science.gov (United States)

    Mirfayzi, S R; Kar, S; Ahmed, H; Krygier, A G; Green, A; Alejo, A; Clarke, R; Freeman, R R; Fuchs, J; Jung, D; Kleinschmidt, A; Morrison, J T; Najmudin, Z; Nakamura, H; Norreys, P; Oliver, M; Roth, M; Vassura, L; Zepf, M; Borghesi, M

    2015-07-01

    Calibration of three scintillators (EJ232Q, BC422Q, and EJ410) in a time-of-flight arrangement using a laser drive-neutron source is presented. The three plastic scintillator detectors were calibrated with gamma insensitive bubble detector spectrometers, which were absolutely calibrated over a wide range of neutron energies ranging from sub-MeV to 20 MeV. A typical set of data obtained simultaneously by the detectors is shown, measuring the neutron spectrum emitted from a petawatt laser irradiated thin foil. PMID:26233373

  5. A neutron time of flight spectrometer appropriate for D-T plasma diagnostics

    International Nuclear Information System (INIS)

    A neutron time-of-flight spectrometer with 2 m flight path for diagnostics of deuterium plasmas in JET is presently under construction. An upgrade of this spectrometer to make it appropriate for 14-MeV neutron spectroscopy is presented here. It is suggested to use backscattering in a deuterium based scintillator. The flight path length is 1-2 m and the efficiency is of the order of 2.10-5 cm-5 . Results from test of principle are presented with estimates for neutron and gamma backgrounds

  6. Calibration of time of flight detectors using laser-driven neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Mirfayzi, S. R.; Kar, S., E-mail: s.kar@qub.ac.uk; Ahmed, H.; Green, A.; Alejo, A.; Jung, D. [Centre for Plasma Physics, School of Mathematics and Physics, Queen’s University Belfast, Belfast BT7 1NN (United Kingdom); Krygier, A. G.; Freeman, R. R. [Department of Physics, The Ohio State University, Columbus, Ohio 43210 (United States); Clarke, R. [Central Laser Facility, Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0QX (United Kingdom); Fuchs, J.; Vassura, L. [LULI, Ecole Polytechnique, CNRS, Route de Saclay, 91128 Palaiseau Cedex (France); Kleinschmidt, A.; Roth, M. [Institut für Kernphysik, Technische Universität Darmstadt, Schloßgartenstrasse 9, D-64289 Darmstadt,Germany (Germany); Morrison, J. T. [Propulsion Systems Directorate, Air Force Research Lab, Wright Patterson Air Force Base, Ohio 45433 (United States); Najmudin, Z.; Nakamura, H. [Blackett Laboratory, Department of Physics, Imperial College, London SW7 2AZ (United Kingdom); Norreys, P. [Central Laser Facility, Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0QX (United Kingdom); Department of Physics, University of Oxford, Oxford OX1 3PU (United Kingdom); Oliver, M. [Department of Physics, University of Oxford, Oxford OX1 3PU (United Kingdom); Zepf, M. [Centre for Plasma Physics, School of Mathematics and Physics, Queen’s University Belfast, Belfast BT7 1NN (United Kingdom); Helmholtz Institut Jena, D-07743 Jena (Germany); Borghesi, M. [Centre for Plasma Physics, School of Mathematics and Physics, Queen’s University Belfast, Belfast BT7 1NN (United Kingdom); Institute of Physics of the ASCR, ELI-Beamlines Project, Na Slovance 2, 18221 Prague (Czech Republic)

    2015-07-15

    Calibration of three scintillators (EJ232Q, BC422Q, and EJ410) in a time-of-flight arrangement using a laser drive-neutron source is presented. The three plastic scintillator detectors were calibrated with gamma insensitive bubble detector spectrometers, which were absolutely calibrated over a wide range of neutron energies ranging from sub-MeV to 20 MeV. A typical set of data obtained simultaneously by the detectors is shown, measuring the neutron spectrum emitted from a petawatt laser irradiated thin foil.

  7. Application of the Time-of-Flight Method to Neutron-Diffraction Studies

    International Nuclear Information System (INIS)

    The pulsed reactor of the Joint Institute for Nuclear Research was used to study neutron diffraction in polycrystalline samples. Using a fixed scattering angle, the authors measured the effect of neutron flight time, i.e. wavelength, on scattering intensity. The method described was used successfully to investigate the crystalline and magnetic structures of BiFeO3, studied earlier by the usual neutron diffraction method with poorer resolution. Splitting of a number of peaks was observed, caused by slight rhombohedral distortion of the cell. From this it could be determined that below zero point the magnetic moments of the Fe ions are oriented parallel to the [111] axis. (author)

  8. Complementarity of real-time neutron and synchrotron radiation structural investigations in molecular biology

    International Nuclear Information System (INIS)

    General problems of the complementarity of different physical methods and specific features of the interaction between neutron and matter and neutron diffraction with respect to the time of flight are discussed. The results of studying the kinetics of structural changes in lipid membranes under hydration and self-assembly of the lipid bilayer in the presence of a detergent are reported. The possibilities of the complementarity of neutron diffraction and X-ray synchrotron radiation and developing a free-electron laser are noted.

  9. Collide@CERN Geneva

    CERN Document Server

    CERN. Geneva; Kieffer, Robert; Blas Temino, Diego; Bertolucci, Sergio; Mr. Decelière, Rudy; Mr. Hänni, Vincent

    2014-01-01

    CERN, the Republic and Canton of Geneva, and the City of Geneva are delighted to invite you to “Collide@CERN Geneva Music”. Come to the public lecture about collisions between music and particle physics by the third winners of Collide@CERN Geneva, Vincent Hänni & Rudy Decelière, and their scientific inspiration partners, Diego Blas and Robert Kieffer. The event marks the beginning of their residency at CERN, and will be held at the CERN Globe of Science and Innovation on 16 October 2014 at 19.00. Doors will open at 18.30.

  10. CERN Cricket Club

    CERN Multimedia

    CERN Cricket Club

    2010-01-01

    CERN Cricket Club Match Reports The cricket season is well under way, despite the weather, and several matches have been played. The match reporters have, however, found it too difficult to limit their reports to ¼ of a page, hence the reports have not appeared in the bulletin. All reports can be found at http://cern.ch/Club-Cricket/reports/reports.html The list of forthcoming matches can be consulted at http://cern.ch/Club-Cricket/fixtures.html Further information about the CERN Cricket Club can be found at http://cern.ch/Club-Cricket/

  11. Britain at CERN

    CERN Multimedia

    CERN Press Office. Geneva

    1996-01-01

    On 8 October, H.E. Mr David Beattie, British Ambassador to Switzerland, Mr John R. Nichols, H.M. Consul-General in Geneva and, Prof. Christopher Llewellyn Smith, CERN*'s Director General, formally opened the industrial exhibition of thirty-three British hi-tech companies at CERN, which takes place from 8 to 11 October, 1996. The exhibition offers British companies the opportunity to display their products in fields that are of immediate importance to the scientists, engineers and technicians working at CERN, and also to scientists from non-Member States who take part in research projects at CERN.

  12. Romania's flag raised at CERN

    CERN Multimedia

    Corinne Pralavorio

    2016-01-01

    A ceremony was held for the raising of the Romanian flag alongside the flags of CERN’s 21 other Member States.   The Romanian flag is raised alongside the flags of CERN’s other Member States, in the presence of the Romanian President, CERN’s Director-General, the President of the CERN Council and a large Romanian delegation. (Image: Maximilien Brice/ Sophia Bennett/CERN) On Monday, 5 September, the Romanian flag was raised in front of CERN for the first time, marking the country’s accession to Membership of the Organization. The blue, yellow and red flag joined those of the other 21 Member States of CERN in a ceremony attended by the President of Romania, Klaus Iohannis, the Romanian Minister for Education and Scientific Research, Mircea Dumitru, and several other members of the President’s office, the government and academia in Romania. The country officially became a CERN Member State on 17 July 2016, after 25 years of collaboration between the...

  13. Studies of parity and time reversal symmetries in neutron scattering from 165Ho

    International Nuclear Information System (INIS)

    We describe searches for parity and time reversal violations in the scattering of polarized neutrons from polarized and aligned 165Ho targets. We have completed a search with 7.1 and 11.0 MeV neutrons for PoddTodd terms in the elastic scattering forward amplitude of the form s.(Ixk), where s is the neutron spin, I is the target spin and k is the neutron momentum vector. The target was a single crystal of holmium, polarized horizontally along its b axis by a 1 Tesla magnetic field. The neutrons were polarized vertically. Differences in the neutron transmission were measured for neutrons with spins parallel (antiparallel) to Ixk. The P,T violating analyzing powers were found to be consistent with zero at the few 10-3 level: ρP,T(7.1 MeV)=-0.88(±2.02)x10-3, ρP,T(11.0 MeV)=-0.4(±2.88)x10-3. We have also attempted to find enhancements with MeV neutrons in P-violation due to the terms s.k. We are preparing an aligned target cryostat for investigations of PevenTodd terms {(I.k)(Ixk)xs} in neutron scattering. The target will be a single crystal cylinder of 165Ho cooled to 100 mK in a bath of liquid helium and rotated by a shaft from a room temperature stepping motor. The cylinder will be oriented vertically and the alignment (c) axis oriented horizontally. Warming or rotation of the sample allows one to separate effects that mimic the sought-after time reversal violating term. (orig.)

  14. Studies of parity and time reversal symmetries in neutron scattering from165Ho

    Science.gov (United States)

    Haase, D. G.; Gould, C. R.; Koster, J. E.; Roberson, N. R.; Seagondollar, L. W.; Soderstrum, J. P.; Schneider, M. B.; Zhu, X.

    1988-12-01

    We describe searches for parity and time reversal violations in the scattering of polarized neutrons from polarized and aligned165Ho targets. We have completed a search with 7.1 and 11.0 MeV neutrons for PoddTodd terms in the elastic scattering forward amplitude of the form s. ( I×K), where s is the neutron spin, I is the target spin and k is the neutron momentum vector. The target was a single crystal of holmium, polarized horizontally along its b axis by a 1 Tesla magnetic field. The neutrons were polarized vertically. Differences in the neutron transmission were measured for neutrons with spins parallel (antiparallel) to I×k. The P,T violating analyzing powers were found to be consistent with zero at the few 10-3 level: ρP,T(7.1 MeV)=-0.88 (±2.02) x 10-3, ρP,T(11.0 MeV)=-0.4 (±2.88) x 10-3. We have also attempted to find enhancements with MeV neutrons in P-violation due to the term s k. We are preparing an aligned target cryostat for investigations of PevenTodd terms {bd(Ik)(I×k)s} in neutron scattering. The target will be a single crystal cylinder of165Ho cooled to 100 mK in a bath of liquid helium and rotated by a shaft from a room temperature stepping motor. The cylinder will be oriented vertically and the alignment ( c) axis oriented horizontally. Warming or rotation of the sample allows one to separate effects that mimic the sought-after time reversal violating term.

  15. CERN honours Georges Charpak

    CERN Multimedia

    2009-01-01

    CERN pays tribute to the work of Georges Charpak at a colloquium in honour of his 85th birthday. var flash_video_player=get_video_player_path(); insert_player_for_external('Video/Public/Movies/2009/CERN-MOVIE-2009-008/CERN-MOVIE-2009-008-0753-kbps-480x360-25-fps-audio-64-kbps-44-kHz-stereo', 'mms://mediastream.cern.ch/MediaArchive/Video/Public/Movies/2009/CERN-MOVIE-2009-008/CERN-MOVIE-2009-008-Multirate-200-to-753-kbps-480x360.wmv', 'false', 480, 360, 'https://mediastream.cern.ch/MediaArchive/Video/Public/Movies/2009/CERN-MOVIE-2009-008/CERN-MOVIE-2009-008-posterframe-480x360-at-10-percent.jpg', '1167500', true, 'Video/Public/Movies/2009/CERN-MOVIE-2009-008/CERN-MOVIE-2009-008-0600-kbps-maxH-360-25-fps-audio-128-kbps-48-kHz-stereo.mp4'); Watch the video conference of Georges Charpak.   On 9 March CERN’s Main Auditorium was the venue for a fascinating and moving celebration marking the 85th birthday of Georges Charpak, who was awarded the Nobel Prize for Physics in 1992 for his inven...

  16. Signal and Noise Analysis in TRION -Time-Resolved Integrative Optical Fast Neutron Detector

    OpenAIRE

    Vartsky, D.; Feldman, G.; Mor, I.; Goldberg, M B; Bar, D.; Dangendorf, V.

    2008-01-01

    TRION is a sub-mm spatial resolution fast neutron imaging detector, which employs an integrative optical time-of-flight technique. The detector was developed for fast neutron resonance radiography, a method capable of detecting a broad range of conventional and improvised explosives. In this study we have analyzed in detail, using Monte-Carlo calculations and experimentally determined parameters, all the processes that influence the signal and noise in the TRION detector. In contrast to event...

  17. 2013 CERN Road Race

    CERN Multimedia

    Klaus Hanke

    2013-01-01

    The 2013 edition of the annual CERN Road Race will be held on Wednesday 18 September at 18.15.   The 5.5 km race takes place over 3 laps of a 1.8 km circuit in the West Area of the Meyrin site, and is open to everyone working at CERN and their families. There are runners of all speeds, with times ranging from under 17 to over 34 minutes, and the race is run on a handicap basis, by staggering the starting times so that (in theory) all runners finish together. Children (< 15 years) have their own race over 1 lap of 1.8 km. As usual, there will be a “best family” challenge (judged on best parent + best child). Trophies are awarded in the usual men’s, women’s and veterans’ categories, and there is a challenge for the best age/performance. Every adult will receive a souvenir prize, financed by a registration fee of 10 CHF. Children enter free (each child will receive a medal). More information, and the online entry form, can be found at: htt...

  18. 2013 CERN Road Race

    CERN Multimedia

    Klaus Hanke

    2013-01-01

    The 2013 annual CERN Road Race will be held on Wednesday 18 September at 6.15 p.m.   The 5.5 km race takes place over 3 laps of a 1.8 km circuit in the West Area of the Meyrin site, and is open to everyone working at CERN and their families. There are runners of all speeds, with times ranging from under 17 to over 34 minutes, and the race is run on a handicap basis, by staggering the starting times so that (in theory) all runners finish together. Children (< 15 years) have their own race over 1 lap of 1.8 km. As usual, there will be a “best family” challenge (judged on best parent and best child). Trophies are awarded in the usual men’s, women’s and veterans’ categories, and there is a challenge for the best age/performance. Every adult will receive a souvenir prize, financed by a registration fee of 10 CHF. Children enter free (each child will receive a medal). More information, and the online entry form, can be found here.

  19. Technical infrastructure monitoring at CERN

    CERN Document Server

    Stowisek, Jan; Suwalska, Anna

    2006-01-01

    The Technical Infrastructure Monitoring system (TIM) is used to monitor and control CERN's technical services from the CERN Control Centre (CCC). The system's primary function is to provide CCC operators with reliable real-time information about the state of the laboratory's extensive and widely distributed technical infrastructure. TIM is also used to monitor all general services required for the operation of CERN's accelerator complex and the experiments. A flexible data acquisition mechanism allows TIM to interface with a wide range of technically diverse installations, using industry standard protocols wherever possible and custom designed solutions where needed. The complexity of the data processing logic, including persistence, logging, alarm handling, command execution and the evaluation of datadriven business rules is encapsulated in the system's business layer. Users benefit from a suite of advanced graphical applications adapted to operations (synoptic views, alarm consoles, data analysis tools etc....

  20. The Evolution of CERN EDMS

    CERN Document Server

    Wardzinska, Aleksandra; Bray, Rachel; Delamare, Christophe; Arza, Griselda Garcia; Krastev, Tsvetelin; Pater, Krzysztof; Suwalska, Anna; Widegren, David

    2015-01-01

    Large-scale long-term projects such as the LHC require the ability to store, manage, organize and distribute large amounts of engineering information, covering a wide spectrum of fields. This information is a living material, evolving in time, following specific lifecycles. It has to reach the next generations of engineers so they understand how their predecessors designed, crafted, operated and maintained the most complex machines ever built.This is the role of CERN EDMS. The Engineering and Equipment Data Management Service has served the High Energy Physics Community for over 15 years. It is CERN's official PLM (Product Lifecycle Management), supporting engineering communities in their collaborations inside and outside the laboratory. EDMS is integrated with the CAD (Computer-aided Design) and CMMS (Computerized Maintenance Management) systems used at CERN providing tools for engineers who work in different domains and who are not PLM specialists.Over the years, human collaborations and machines grew in si...

  1. CERN theorist gets a Heineman

    CERN Multimedia

    2006-01-01

    A CERN theorist is among the recipients of the American Physical Society's annual Dannie Heineman Prize for Mathematical Physics. The 2006 recipients of the Dannie Heineman Prize. From left to right : Peter van Nieuwenhuizen of the Stony Brook University (New York), Sergio Ferrara of CERN and Daniel Freedman of the Massachusetts Institute of Technology. Picture taken in Rome in June 2005. The 2006 prize recognises the development of supergravity by Sergio Ferrara of CERN, Daniel Freedman of the Massachusetts Institute of Technology and Peter van Nieuwenhuizen of the State University of New York, Stony Brook. The trio won the award for constructing and developing the first super-symmetric extension of Einstein's theory of general relativity. By providing a special class of field theories for the low-energy manifestation of superstrings, supergravity has played an important role in theoretical physics in the last thirty years. This is not the first time that supergravity has won an award. In 1993, the trio ...

  2. CERN Scientific Book Fair 2013

    CERN Multimedia

    CERN Library

    2013-01-01

    The CERN Bookshop and CERN Library invite you to attend the 2013 CERN Book Fair, a two-day scientific event offering you the opportunity to meet key publishers and to browse and purchase books at significant discounts.   Key publishers will present a selection of titles in physics, technology, mathematics, engineering, computing and popular science. You are welcome to come along and meet the publishers’ representatives or simply have a look at the books on sale. The fair will take place in the Main Building (Bldg. 500) on the ground floor near Restaurant 1 on Monday 9 and Tuesday 10 September. Participating or represented publishers include: Oxford University Press, Princeton University Press, Springer, Wiley, and World Scientific-Imperial College Press. Fair opening times:  - Monday 9 September 9:00 - 18:00  - Tuesday 10 September 9:00 - 18:00

  3. CERN scientific book fair 2010

    CERN Multimedia

    CERN Library

    2010-01-01

    The CERN Bookshop and CERN Library invite you to attend the 2010 CERN Book Fair, a two-day scientific event offering you the opportunity to meet key publishers and to browse and purchase books at significant discounts.   Some twelve companies will be present and will bring with them a selection of titles in physics, technology, mathematics, engineering, computing and popular science. You are welcome to come along and meet the publishers’ representatives or simply have a look to the books on offer. The Fair will take place in the Main Building (bldg. 500) on the ground floor near the Restaurant 1 on Tuesday 7th and Wednesday 8th September. Participating or represented publishers include: Cambridge University Press, EPFL Press – PPUR, Oxford University Press, Imperial College Press, McGraw-Hill, Oxford University Press, Pearson Education, Princeton University Press, Springer, Taylor and Francis, Wiley, World Scientific. Fair opening times: Tuesday 7 September 9:00 &ndash...

  4. Calculation of the angular distribution of delay times in neutron scattering on 58Ni nuclei

    International Nuclear Information System (INIS)

    Angular distributions of average delay times and time variances are calculated for resonance-neutron scattering on 58Ni nuclei at neutron energies in the range E = 600−700 keV. The effect of the energy spectrum and polarization of the beam on the scattering-process time is discussed. The angular dependence of the time law is also considered for the decay of an intermediate compound nuclear system. It is shown that the results of stationary and nonstationary calculations are in good agreement.

  5. Calculation of the angular distribution of delay times in neutron scattering on {sup 58}Ni nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Prokopets, G. A., E-mail: gaprok@uos.net.ua [National University of Kyiv-Mohyla Academy (Ukraine)

    2011-05-15

    Angular distributions of average delay times and time variances are calculated for resonance-neutron scattering on {sup 58}Ni nuclei at neutron energies in the range E = 600-700 keV. The effect of the energy spectrum and polarization of the beam on the scattering-process time is discussed. The angular dependence of the time law is also considered for the decay of an intermediate compound nuclear system. It is shown that the results of stationary and nonstationary calculations are in good agreement.

  6. Neutrino oscillation experiments at CERN

    International Nuclear Information System (INIS)

    Two proposals for neutrino oscillation experiments have been submitted at CERN at this time. A Padova-Pisa-Athens-Wisconsin group proposes to use BEBC to observe ν/sub e/ events in a nearly pure ν/sub μ/ beam, and the CERN-Dortmund-Heidelberg-Saclay group proposes to use the neutrino detector presently installed in the SPS high energy neutrino beam to look for the disappearance of ν/sub μ/. The main features of the two experiments are presented and discussed

  7. 50 years CERN Courier Celebration

    CERN Multimedia

    2009-01-01

    The 50th anniversary of the first publication of the CERN Courier provided the opportunity for a modest celebration on 2 September 2009. All six of the principal editors that the magazine has had over its 50-years history met together for the first time. After getting acquainted and reacquainted over lunch, they gathered in the library at CERN to answer questions about the production of the magazine over the years. From left to right, from the present editor to the first one: Christine Sutton, James Gillies, Gordon Fraser, Brian Southworth, Alec Hester and Roger Anthoine.

  8. Neutron generator burst timing measured using a pulse shape discrimination plastic scintillator with silicon photomultiplier readout

    Science.gov (United States)

    Preston, R. M.; Eberhardt, J. E.; Tickner, J. R.

    2013-12-01

    An EJ-299-34 plastic scintillator with silicon photomultiplier (SiPM) readout was used to measure the fast neutron output of a pulsed Thermo-Fisher A-325 Deuterium-Tritium sealed tube neutron generator (STNG). The SiPM signals were handled by a prototype digital pulse processing system, based on a free-running analogue to digital converter feeding a digital signal processor (DSP). Pulse shape discrimination was used to distinguish between detected fast-neutrons and gammas. Pulse detection, timing, energy and shape were all processed by the DSP in real-time. The time-dependency of the neutron output of the STNG was measured for various pulsing schemes. The switch-on characteristics of the tube strongly depended on the operating settings, with the delay between pulse turn-on and the production of neutrons ranging between 13 μs to 74 μs for the tested pulse rates and duty cycles. This work will facilitate the optimization and modeling of apparatus that use the neutron generator's pulsing abilities.

  9. Neutron generator burst timing measured using a pulse shape discrimination plastic scintillator with silicon photomultiplier readout

    International Nuclear Information System (INIS)

    An EJ-299-34 plastic scintillator with silicon photomultiplier (SiPM) readout was used to measure the fast neutron output of a pulsed Thermo-Fisher A-325 Deuterium-Tritium sealed tube neutron generator (STNG). The SiPM signals were handled by a prototype digital pulse processing system, based on a free-running analogue to digital converter feeding a digital signal processor (DSP). Pulse shape discrimination was used to distinguish between detected fast-neutrons and gammas. Pulse detection, timing, energy and shape were all processed by the DSP in real-time. The time-dependency of the neutron output of the STNG was measured for various pulsing schemes. The switch-on characteristics of the tube strongly depended on the operating settings, with the delay between pulse turn-on and the production of neutrons ranging between 13 μs to 74 μs for the tested pulse rates and duty cycles. This work will facilitate the optimization and modeling of apparatus that use the neutron generator's pulsing abilities

  10. Analysis of the neutron time-of-flight spectra from inertial confinement fusion experiments

    Science.gov (United States)

    Hatarik, R.; Sayre, D. B.; Caggiano, J. A.; Phillips, T.; Eckart, M. J.; Bond, E. J.; Cerjan, C.; Grim, G. P.; Hartouni, E. P.; Knauer, J. P.; Mcnaney, J. M.; Munro, D. H.

    2015-11-01

    Neutron time-of-flight diagnostics have long been used to characterize the neutron spectrum produced by inertial confinement fusion experiments. The primary diagnostic goals are to extract the d + t → n + α (DT) and d + d → n + 3He (DD) neutron yields and peak widths, and the amount DT scattering relative to its unscattered yield, also known as the down-scatter ratio (DSR). These quantities are used to infer yield weighted plasma conditions, such as ion temperature (Tion) and cold fuel areal density. We report on novel methodologies used to determine neutron yield, apparent Tion, and DSR. These methods invoke a single temperature, static fluid model to describe the neutron peaks from DD and DT reactions and a spline description of the DT spectrum to determine the DSR. Both measurements are performed using a forward modeling technique that includes corrections for line-of-sight attenuation and impulse response of the detection system. These methods produce typical uncertainties for DT Tion of 250 eV, 7% for DSR, and 9% for the DT neutron yield. For the DD values, the uncertainties are 290 eV for Tion and 10% for the neutron yield.

  11. Analysis of the neutron time-of-flight spectra from inertial confinement fusion experiments

    Energy Technology Data Exchange (ETDEWEB)

    Hatarik, R., E-mail: hatarik1@llnl.gov; Sayre, D. B.; Caggiano, J. A.; Phillips, T.; Eckart, M. J.; Bond, E. J.; Cerjan, C.; Grim, G. P.; Hartouni, E. P.; Mcnaney, J. M.; Munro, D. H. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Knauer, J. P. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States)

    2015-11-14

    Neutron time-of-flight diagnostics have long been used to characterize the neutron spectrum produced by inertial confinement fusion experiments. The primary diagnostic goals are to extract the d + t → n + α (DT) and d + d → n + {sup 3}He (DD) neutron yields and peak widths, and the amount DT scattering relative to its unscattered yield, also known as the down-scatter ratio (DSR). These quantities are used to infer yield weighted plasma conditions, such as ion temperature (T{sub ion}) and cold fuel areal density. We report on novel methodologies used to determine neutron yield, apparent T{sub ion}, and DSR. These methods invoke a single temperature, static fluid model to describe the neutron peaks from DD and DT reactions and a spline description of the DT spectrum to determine the DSR. Both measurements are performed using a forward modeling technique that includes corrections for line-of-sight attenuation and impulse response of the detection system. These methods produce typical uncertainties for DT T{sub ion} of 250 eV, 7% for DSR, and 9% for the DT neutron yield. For the DD values, the uncertainties are 290 eV for T{sub ion} and 10% for the neutron yield.

  12. Neutron intensity modulation and time-focusing with integrated Larmor and resonant frequency techniques

    Science.gov (United States)

    Zhao, Jinkui; Hamilton, William A.; Lee, Sung-Woo; Robertson, J. L.; Crow, Lowell; Kang, Yoon W.

    2015-09-01

    The analysis of neutron diffraction experiments often assumes that neutrons are elastically scattered from the sample. However, there is growing evidence that a significant fraction of the detected neutrons is in fact inelastically scattered, especially from soft materials and aqueous samples. Ignoring these inelastic contributions gives rise to inaccurate experimental results. To date, there has been no simple method with broad applicability for inelastic signal separation in neutron diffraction experiments. Here, we present a simple and robust method that we believe could be suited for this purpose. We use two radio frequency resonant spin flippers integrated with a Larmor precession field to modulate the neutron intensity and to encode the inelastic scattering information into the neutron data. All three components contribute to the spin encoding. The Larmor field serves several additional purposes. Its usage facilitates neutron time-focusing, eliminates the need for stringent magnetic shielding, and allows for compact setups. The scheme is robust, simple, and flexible. We believe that, with further improvements, it has the potential of adding inelastic signal discrimination capabilities to many existing diffraction instruments in the future.

  13. The Nuclear Physics Programme at CERN (1/3)

    CERN Document Server

    CERN. Geneva

    2013-01-01

    This lecture series will focus on the two major facilities at CERN for nuclear physics: ISOLDE and nToF. ISOLDE is one of the world's leading radioactive beam facilities which can produce intense beams of unstable nuclei. Some of these beams can also be re-acclerated to energies around the Coulomb barrier and undergo nuclear reactions in turn. ISOLDE can address a wide range of Physics from nuclear structure to nuclear astrophysics (the origin of the chemical elements) and fundamental physics. The second major facility is nToF which is a neutron time-of-flight facility. Intense neutron beams are used to study nuclear reactions important both for nuclear astrophysics and for present and future reactor cycles. An overview will be given of these two facilities including highlights of their Physics programmes and the perspectives for the future.

  14. Correlation analysis with neutron count distributions in randomly or signal triggered time intervals for assay of special fissile materials

    International Nuclear Information System (INIS)

    A mathematical model is derived for the probability distribution of neutron signal multiplets inside randomly and signal triggered time intervals for a generalized time response function of the neutron detector assembly. The theory is applied to assemblies with an exponential time decay of its neutron population. The probability distributions, their factorial moments, and moments are expressed as a function of the spontaneous fission rate, (α-n) reaction rate, neutron detection probability, probability that a neutron generates a fast fission, and nuclear data. Measurements with plutonium sample are analyzed to check the derived algorithms for the factorial moments of the two probability distributions

  15. Calculation of neutron die-away times in a large-vehicle portal monitor

    International Nuclear Information System (INIS)

    Monte Carlo methods have been used to calculate neutron die-away times in a large-vehicle portal monitor. These calculations were performed to investigate the adequacy of using neutron die-away time measurements to detect the clandestine movement of shielded nuclear materials. The geometry consisted of a large tunnel lined with He3 proportional counters. The time behavior of the (n,p) capture reaction in these counters was calculated when the tunnel contained a number of different tractor-trailer load configurations. Neutron die-away times obtained from weighted least squares fits to these data were compared. The change in neutron die-away time due to the replacement of cargo in a fully loaded truck with a spherical shell containing 240 kg of borated polyethylene was calculated to be less than 3%. This result together with the overall behavior of neutron die-away time versus mass inside the tunnel strongly suggested that measurements of this type will not provide a reliable means of detecting shielded nuclear materials in a large vehicle. 5 figures, 4 tables

  16. HYSPEC : A CRYSTAL TIME OF FLIGHT HYBRID SPECTROMETER FOR THE SPALLATION NEUTRON SOURCE.

    Energy Technology Data Exchange (ETDEWEB)

    SHAPIRO,S.M.; ZALIZNYAK,I.A.

    2002-12-30

    This document lays out a proposal by the Instrument Development Team (IDT) composed of scientists from leading Universities and National Laboratories to design and build a conceptually new high-flux inelastic neutron spectrometer at the pulsed Spallation Neutron Source (SNS) at Oak Ridge. This instrument is intended to supply users of the SNS and scientific community, of which the IDT is an integral part, with a platform for ground-breaking investigations of the low-energy atomic-scale dynamical properties of crystalline solids. It is also planned that the proposed instrument will be equipped with a polarization analysis capability, therefore becoming the first polarized beam inelastic spectrometer in the SNS instrument suite, and the first successful polarized beam inelastic instrument at a pulsed spallation source worldwide. The proposed instrument is designed primarily for inelastic and elastic neutron spectroscopy of single crystals. In fact, the most informative neutron scattering studies of the dynamical properties of solids nearly always require single crystal samples, and they are almost invariably flux-limited. In addition, in measurements with polarization analysis the available flux is reduced through selection of the particular neutron polarization, which puts even more stringent limits on the feasibility of a particular experiment. To date, these investigations have mostly been carried out on crystal spectrometers at high-flux reactors, which usually employ focusing Bragg optics to concentrate the neutron beam on a typically small sample. Construction at Oak Ridge of the high-luminosity spallation neutron source, which will provide intense pulsed neutron beams with time-averaged fluxes equal to those at medium-flux reactors, opens entirely new opportunities for single crystal neutron spectroscopy. Drawing upon experience acquired during decades of studies with both crystal and time-of-flight (TOF) spectrometers, the IDT has developed a conceptual

  17. Comedy Collider presents: No cause for conCERN

    CERN Multimedia

    Traczyk, Piotr

    2014-01-01

    Comedy Collider presents: No cause for conCERN was the highly anticipated follow up to LHComedy: CERN After Dark, starring an entirely new ensemble of comedy talent. Time: 13th June 2014, 19:30 for 20:00 Location: Globe of Science and Innovation, CERN, Geneva, Switzerland

  18. Time correlated measurements using plastic scintillators with neutron-photon pulse shape discrimination

    Science.gov (United States)

    Richardson, Norman E., IV

    nuclear and radiological material. Moreover, the production of 3He isotope as a byproduct of security programs was drastically decreased. This isotope shortage coupled with the disadvantages of relying on a detector that requires neutron moderation before the detection of fission neutrons, poses a significant challenge in supporting the existing detection systems and the development of future technologies. To address this problem, a reliable and accurate alternative technology to detect neutrons emitted in fissions must be developed. One such alternative technology that shows promise in this application is the use of scintillators based on solid state materials (plastics) which are sensitive to fast neutrons. However, plastic scintillators are also sensitive to photons. Hence, it is necessary to separate the neutron signals from the photon signals, using the pulse shape discrimination (PSD) analysis. The PSD is based on the comparison of the pulse shapes of digitized signal waveforms. This approach allows for the measurement of fast neutrons without the necessity of their moderation. Because the fission spectrum neutrons are mainly fast, methods employing fast neutron detection are applicable for the assay of fissile materials. In addition, the average time of scintillation of the plastic medium is much shorter than those of the gaseous counters, thus allowing scintillation detectors to be used in high count rate environments. Furthermore, the temporal information of the fast neutron detection using multiple sensors enables the time correlation analysis of the fission neutron multiplicity. The study of time correlation measurements of fast neutrons using the array of plastic scintillators is the basis of this work. The array of four plastic scintillator detectors equipped with the digital data acquisition and analysis system was developed. The digital PSD analysis of detector signals "on-the-fly" was implemented for the array. The time coincidence measurement technique

  19. Neutrons are flying

    CERN Multimedia

    2000-01-01

    View of the n_TOF tube with members of the design and construction team of the facility(from left to right: R. Magnin/LHC, E. Radermacher/EP, P. Cennini/EP and R. Cappi/PS). A new experimental facility was inaugurated at CERN on Wednesday 8 November. The neutron Time Of Flight (n_TOF) facility received its first protons from the PS at 10:55. With an intensity of 1 x 1011 protons per cycle on the n_TOF target, an intense neutron beam has been produced at CERN for the first time, opening the door to many new avenues of research including, for example, neutron induced cross-section measurements. The facility is an offspring of the work by Carlo Rubbia and his group on the novel idea of an Energy Amplifier. The basic idea was successfully tested at the PS with the FEAT experiment and later with the TARC experiment, where the feasibility of transmutation of long-lived products by Adiabatic Resonance Crossing (ARC) was confirmed. This led to the possibility of radio-isotope production for medical applications, fo...

  20. Cern collisions light up Copenhagen

    CERN Multimedia

    Banks, Michael

    2010-01-01

    "Anyone passing by the Niels Bohr Institute in Copenhagen, Denmark, might be startled by some strange moving lights on the facade of the institute's main building. In fact, the dancing beams show, almost in real time, collisions form the Atlas experiment at Cern's Large Hadron Collider (LHC)" (1 paragraph)

  1. Time step control for solving the transient even-parity neutron transport equation

    International Nuclear Information System (INIS)

    Recently a discretization (in time) scheme for the transient even-parity neutron transport equation was successfully developed and implemented in the VARIANT/KIN3D code. Starting from this result we have first more thoroughly investigated the order of approximation, with respect to the time variable, arising from such a scheme especially having in mind the use of a variable time step. Based on the results of this analysis we have then introduced a time discretization scheme capable of keeping the mathematical structure of the equation also in the framework of a variable time step. Starting from this new scheme we have also introduced an automatic time step control option based on the estimation of the third order time derivative by comparing the backward and centered Euler schemes. In the paper, the developed theoretical background is presented and results for a small size fast reactor are shown. We have investigated the time step control option and find its behavior being in agreement with the physical phenomena. In particular the increase of the delayed neutron fraction changes the behavior in the expected manner. The time step control was, in fact, able to detect the presence of additional time scales introduced by two families of delayed neutrons in comparison with the case with almost no delayed neutrons. (authors)

  2. New Converging Collimator for Cold Neutrons Time-Of-Flight Measurements

    Science.gov (United States)

    Naguib, K.; Sallam, O. H.; Salama, Mohamed

    An idea to design a new converging collimator for cold neutron time-of-flight measurements is presented. Using this new facility in combination with a neutron time-of-flight spectrometer, we may have neutron intensity gain factors about three times that obtained using the conventional straight slit collimators. Expressions for calculating the collimators dimensions as well as the intensity gain and the time resolution broading were presented.Translated AbstractEin neuer, konvergierender Kollimator für Flugzeitmessungen mit langsamen NeutronenDie Idee der Konstruktion eines neuen, konvergierenden Kollimators für Flugzeitmessungen mit langsamen Neutronen wird vorgestellt. Mit diesem neuen Gerät in Kombination mit einem Neutronenflugzeitspektrometer sollte sich ein Intensitätsgewinn von drei gegenüber konventionellen Anordnungen ergeben. Die Kollimatordimensionen, der Intensitätsgewinn und die Verbreiterung der Zeitauflösung werden berechnet.

  3. The Local-time variations of Lunar Prospector epithermal-neutron data

    CERN Document Server

    Teodoro, L F A; Eke, V E; Elphic, R E; Feldman, W C; Maurice, S; Siegler, M A; Paige, D A

    2015-01-01

    We assess local-time variations of epithermal-neutron count rates measured by the Lunar Prospector Neutron Spectrometer. We investigate the nature of these variations and find no evidence to support the idea that such variations are caused by diurnal variations of hydrogen concentration across the lunar surface. Rather we find an anticorrelation between instrumental temperature and epithermal-neutron count rate. We have also found that the measured counts are dependent on the temperatures of the top decimeters of the lunar subsurface as constrained by the Lunar Reconnaissance Orbiter Diviner Lunar Radiometer Experiment temperature measurements. Finally, we have made the first measurement of the effective leakage depth for epithermal-neutrons of ~20 cm.

  4. A new neutron time-of-flight detector for fuel-areal-density measurements on OMEGA.

    Science.gov (United States)

    Glebov, V Yu; Forrest, C J; Marshall, K L; Romanofsky, M; Sangster, T C; Shoup, M J; Stoeckl, C

    2014-11-01

    A new neutron time-of-flight (nTOF) detector for fuel-areal-density measurements in cryogenic DT implosions was installed on the OMEGA Laser System. The nTOF detector has a cylindrical thin-wall, stainless-steel, 8-in.-diam, 4-in.-thick cavity filled with an oxygenated liquid xylene scintillator. Four gated photomultiplier tubes (PMTs) with different gains are used to measure primary DT and D2 neutrons, down-scattered neutrons in nT and nD kinematic edge regions, and to study tertiary neutrons in the same detector. The nTOF detector is located 13.4 m from target chamber center in a well-collimated line of sight. The design details of the nTOF detector, PMT optimization, and test results on OMEGA will be presented. PMID:25430281

  5. The multipurpose time-of-flight neutron reflectometer 'Platypus' at Australia's OPAL reactor

    International Nuclear Information System (INIS)

    In this manuscript we describe the major components of the Platypus time-of-flight neutron reflectometer at the 20 MW OPAL reactor in Sydney, Australia. Platypus is a multipurpose spectrometer for the characterisation of solid thin films, materials adsorbed at the solid-liquid interface and free-liquid surfaces. It also has the capacity to study magnetic thin films using spin-polarised neutrons. Platypus utilises a white neutron beam (λ=2-20 A) that is pulsed using boron-coated disc chopper pairs; thus providing the capacity to tailor the wavelength resolution of the pulses to suit the system under investigation. Supermirror optical components are used to focus, deflect or spin-polarise the broad bandwidth neutron beams, and typical incident spectra are presented for each configuration. A series of neutron reflectivity datasets are presented, indicating the quality and flexibility of this spectrometer. Minimum reflectivity values of -7 are observed; while maximum thickness values of 325 nm have been measured for single-component films and 483 nm for a multilayer system. Off-specular measurements have also been made to investigate in-plane features as opposed to those normal to the sample surface. Finally, the first published studies conducted using the Platypus time-of-flight neutron reflectometer are presented.

  6. CVD Diamond Detectors for Current Mode Neutron Time-of-Flight Spectroscopy at OMEGA/NIF

    International Nuclear Information System (INIS)

    We have performed pulsed neutron and pulsed laser tests of a CVD diamond detector manufactured from DIAFILM, a commercial grade of CVD diamond. The laser tests were performed at the short pulse UV laser at Bechtel Nevada in Livermore, CA. The pulsed neutrons were provided by DT capsule implosions at the OMEGA laser fusion facility in Rochester, NY. From these tests, we have determined the impulse response to be 250 ps fwhm for an applied E-field of 500 V/mm. Additionally, we have determined the sensitivity to be 2.4 mA/W at 500 V/mm and 4.0 mA/W at 1000 V/mm. These values are approximately 2 to 5x times higher than those reported for natural Type IIa diamond at similar E-field and thickness (1mm). These characteristics allow us to conceive of a neutron time-of-flight current mode spectrometer based on CVD diamond. Such an instrument would sit inside the laser fusion target chamber close to target chamber center (TCC), and would record neutron spectra fast enough such that backscattered neutrons and x-rays from the target chamber wall would not be a concern. The acquired neutron spectra could then be used to extract DD fuel areal density from the downscattered secondary to secondary ratio

  7. CERN Table Tennis Club

    CERN Multimedia

    CERN Table Tennis Club

    2014-01-01

    CERN Table Tennis Club Announcing CERN 60th Anniversary Table Tennis Tournament to take place at CERN, from July 1 to July 15, 2014   The CERN Table Tennis Club, reborn in 2008, is encouraging people at CERN to take more regular exercise. This is why the Club, thanks to the strong support of the CERN Staff Association, installed last season a first outdoor table on the terrace of restaurant # 1, and will install another one this season on the terrace of Restaurant # 2. Table tennis provides both physical exercise and friendly social interactions. The CERN Table Tennis club is happy to use the unique opportunity of the 60th CERN anniversary to promote table tennis at CERN, as it is a game that everybody can easily play, regardless of level. Table tennis is particularly well suited for CERN, as many great physicists play table tennis, as you might already know: “Heisenberg could not even bear to lose a game of table tennis”; “Otto Frisch played a lot of table tennis;...

  8. CERN Yachting club

    CERN Multimedia

    CERN Yachting club

    2015-01-01

    Surely among the most active sports clubs within CERN, the Yachting Club has had a steadily increasing membership over a decade; it is now around 350 but new members are always welcome, especially now at the beginning of a season. Indeed, with the Lottery for places in courses which are one of our highlights, membership has jumped since mid-March. The Lottery is always heavily oversubscribed, which we like to think represents its good reputation for quality of teaching and good fun at the same time. Now those lucky new students are in contact with their teachers, will be buying wetsuits in some cases (dinghy and catamaran courses), joining us for the launch of the fleet (see calendar on website at http://yachting.web.cern.ch/yachting/ycc_home.html ) and  – in many cases – learning sailing as complete beginners. Those Lottery-unlucky can still plan a fun season, with our Thursday Practice evenings, where we can almost always place everyone on a boat for an outing.   ...

  9. EUCYS prizewinner visits CERN

    CERN Multimedia

    Jennifer Toes

    2016-01-01

    Young Turkish student Baris Volkan Gürses visited CERN from 4 to 8 July after winning the prize in the 2015 European Contest for Young Scientists (EUCYS).    Baris Volkan Gürses, EUCYS prizewinner, visiting the Microcosm. After winning both regional and national competitions in Turkey, 18-year-old student Baris Volkan Gürses competed against 169 young scientists and was awarded a visit to CERN by EIROforum for his physics project in EUCYS 2015. His project, entitled “Generation of artificial gravity by using electrostatic force for prevention of muscle atrophy and osteoporosis occurring in gravity-free environments”, focused on the design of a mechanism to help with the impact of spaceflight on the human body. “My objective was to eliminate the negative effects of a gravity-free environment on astronauts who stay in space for longer periods of time, like in the International Space Station,” explained Volkan. &...

  10. New auditorium for CERN

    CERN Multimedia

    Laëtitia Pedroso

    2010-01-01

    Since September 2009 the PH and GS Departments have been working very closely together on the renovation project for Building 222. The building is now being transformed into an auditorium with a seating capacity of 200. Work began on 15 November 2009 and will be completed just in time for the first conferences.   The conference room in B222 a few days ago. After 20 years as premises for the filtering and purification of CERN's drinking water and three years as a hall for the reception tests and testing of electronic equipment for the LHC experiments, Building 222 is about to get another new lease of life. Only the Main Auditorium and the Globe have seating capacities in excess of 200 at CERN. “The problem of the lack of conference rooms with such a seating capacity was raised at the end of 2008 by the PH Department, which proposed this idea. The project was entrusted to the GS Department in 2009,” explains Barthélemy Gossuin, an engineer in the GS Department who is...

  11. Preserving CERN's legacy

    CERN Multimedia

    Antonella Del Rosso

    2015-01-01

    At CERN, scientists from all over the world design and build innovative instruments to be implemented in the cutting-edge machines used in high-energy physics. Those instruments go on to become part of the world’s most powerful accelerators, Nobel-prize-winning detectors, unique antimatter machines, the first web servers… These are historical pieces and belong to our common heritage. But, what happens to them once they are no longer in use?   New endeavours consistently require new technical developments, and the list of “old” objects belonging to a laboratory like CERN increases over time. As innovative as they might have been when they were created, they are often bulky, sometimes very delicate, and do not always look like everyday tools when they are dismantled. How best to deal with them? “A database of objects suitable for scientific exhibitions has been available on CDS for many years,” says Gigi Rolandi, Chair of CER...

  12. Celebrating diversity at CERN

    CERN Multimedia

    2014-01-01

    With international women’s day coming up on 8 March, along with the recent appointment of a new Diversity Programme Leader, it seems timely to take a look at how far we’ve come over recent years in promoting gender equality at CERN. In short, the news is good, but we still have some way to travel.   CERN does not have a policy of positive discrimination, but rather one of presenting a level playing field. We work to ensure, for example, that the diversity of candidates presented for interview reflects the diversity of applicants. It’s an approach that is having the desired effect. Overall, the percentage of female staff members has risen from 17% to 20% over the last decade, with parity being achieved among professional administrators and significant advances being made among research and applied physicists, engineers and technicians. At recruitment, our approach is working: we’re managing to attract growing numbers of women. This brings us to the phen...

  13. Thomas Kibble visits CERN

    CERN Multimedia

    Rosaria Marraffino

    2014-01-01

    Emeritus Professor Sir Thomas W.B. Kibble, from Imperial College London visited LHC for the first time last week and delivered a colloquium on the genesis of electroweak unification and the Brout-Englert-Higgs mechanism.   From left to right: Jim Virdee, Tiziano Camporesi, Tom Kibble and Austin Ball on the visit to CMS. On his way back from Trieste, where he received the Abdus Salam International Centre for Theoretical Physics' Dirac Medal, Tom Kibble stopped by CERN for his first visit to the LHC. Kibble had a standing invitation from Jim Virdee, former CMS spokesperson, who is also a researcher from Imperial College London. Peter Jenni (left) and Tom Kibble tour the ATLAS detector. (Image: Erwan Bertrand) Kibble made the trip to CERN a family outing and brought along 14 relatives,  including his children and grandchildren. He visited the ATLAS detector with Peter Jenni, its former spokesperson, on Friday 10 October. In the afternoon, Kibble delivered a colloquium in the...

  14. Study of calculated and measured time dependent delayed neutron yields. [TX, for calculating delayed neutron yields; MATINV, for matrix inversion; in FORTRAN for LSI-II minicomputer

    Energy Technology Data Exchange (ETDEWEB)

    Waldo, R.W.

    1980-05-01

    Time-dependent delayed neutron emission is of interest in reactor design, reactor dynamics, and nuclear physics studies. The delayed neutrons from neutron-induced fission of /sup 232/U, /sup 237/Np, /sup 238/Pu, /sup 241/Am, /sup 242m/Am, /sup 245/Cm, and /sup 249/Cf were studied for the first time. The delayed neutron emission from /sup 232/Th, /sup 233/U, /sup 235/U, /sup 238/U, /sup 239/Pu, /sup 241/Pu, and /sup 242/Pu were measured as well. The data were used to develop an empirical expression for the total delayed neutron yield. The expression gives accurate results for a large variety of nuclides from /sup 232/Th to /sup 252/Cf. The data measuring the decay of delayed neutrons with time were used to derive another empirical expression predicting the delayed neutron emission with time. It was found that nuclides with similar mass-to-charge ratios have similar decay patterns. Thus the relative decay pattern of one nuclide can be established by any measured nuclide with a similar mass-to-charge ratio. A simple fission product yield model was developed and applied to delayed neutron precursors. It accurately predicts observed yield and decay characteristics. In conclusion, it is possible to not only estimate the total delayed neutron yield for a given nuclide but the time-dependent nature of the delayed neutrons as well. Reactors utilizing recycled fuel or burning actinides are likely to have inventories of fissioning nuclides that have not been studied until now. The delayed neutrons from these nuclides can now be incorporated so that their influence on the stability and control of reactors can be delineated. 8 figures, 39 tables.

  15. Neutron coincidence counting based on time interval analysis with dead time corrected one and two dimensional Rossi-alpha distributions: an application for passive neutron waste assay

    International Nuclear Information System (INIS)

    The report describes a new neutron multiplicity counting method based on Rossi-alpha distributions. The report also gives the necessary dead time correction formulas for the multiplicity counting method. The method was tested numerically using a Monte Carlo simulation of pulse trains. The use of this multiplicity method in the field of waste assay is explained: it can be used to determine the amount of fissile material in a waste drum without prior knowledge of the actual detection efficiency

  16. 2015 CERN-Fermilab HCP Summer School

    CERN Multimedia

    2015-01-01

    CERN and Fermilab are jointly offering a series of "Hadron Collider Physics Summer Schools", to prepare young researchers for these exciting times. The school has alternated between CERN and Fermilab, and will return to CERN for the tenth edition, from 24 June to 3 July 2015. The CERN-Fermilab Hadron Collider Physics Summer School is an advanced school targeted particularly at young postdocs and senior PhD students working towards the completion of their thesis project, in both Experimental High Energy Physics (HEP) and phenomenology. Lecture Topics include: Statistics in HEP, Heavy Flavour, Heavy Ion, Standard Model, Higgs searches and measurements, BSM theory, BSM searches, Top physics, QCD and Monte Carlos, Accelerators, Detectors for the future, Trigger and DAQ, Dark Matter Astroparticle, and two special lectures on Future Colliders, and 20 years after the top discovery. Calendar and Details: Mark your calendar for  24 June - 3 July 2015, when CERN will welcome students to t...

  17. Utilizing the slowing-down-time technique for benchmarking neutron thermalization in graphite

    International Nuclear Information System (INIS)

    Graphite is the moderator/reflector in the Very High Temperature Reactor (VHTR) concept of Generation IV reactors. As a thermal reactor, the prediction of the thermal neutron spectrum in the VHTR is directly dependent on the accuracy of the thermal neutron scattering libraries of graphite. In recent years, work has been on-going to benchmark and validate neutron thermalization in 'reactor grade' graphite. Monte Carlo simulations using the MCNP5 code were used to design a pulsed neutron slowing-down-time experiment and to investigate neutron slowing down and thermalization in graphite at temperatures relevant to VHTR operation. The unique aspect of this experiment is its ability to observe the behavior of neutrons throughout an energy range extending from the source energy to energies below 0.1 eV. In its current form, the experiment is designed and implemented at the Oak Ridge Electron Linear Accelerator (ORELA). Consequently, ORELA neutron pulses are injected into a 70 cm x 70 cm x 70 cm graphite pile. A furnace system that surrounds the pile and is capable of heating the graphite to a centerline temperature of 1200 K has been designed and built. A system based on U-235 fission chambers and Li-6 scintillation detectors surrounds the pile. This system is coupled to multichannel scaling instrumentation and is designed for the detection of leakage neutrons as a function of the slowing-down-time (i.e., time after the pulse). To ensure the accuracy of the experiment, careful assessment was performed of the impact of background noise (due to room return neutrons) and pulse-to-pulse overlap on the measurement. Therefore, the entire setup is surrounded by borated polyethylene shields and the experiment is performed using a source pulse frequency of nearly 130 Hz. As the basis for the benchmark, the calculated time dependent reaction rates in the detectors (using the MCNP code and its associated ENDF-B/VI thermal neutron scattering libraries) are compared to measured

  18. The time-of-flight epithermal neutron spectrum measurement from accelerator based BNCT facility

    International Nuclear Information System (INIS)

    Results of epithermal neutrons spectrum measurement by time-of-flight method for different beam shaping assembly designed for BNCT purposes are presented. Discuss method to realize time-of-flight measurement at accelerator. Results looks are important for beam shaping assembly optimization and accurate and reliable treatment planning. (author)

  19. A scientific database for real-time Neutron Monitor measurements - taking Neutron Monitors into the 21st century

    Science.gov (United States)

    Steigies, Christian

    2012-07-01

    The Neutron Monitor Database project, www.nmdb.eu, has been funded in 2008 and 2009 by the European Commission's 7th framework program (FP7). Neutron monitors (NMs) have been in use worldwide since the International Geophysical Year (IGY) in 1957 and cosmic ray data from the IGY and the improved NM64 NMs has been distributed since this time, but a common data format existed only for data with one hour resolution. This data was first distributed in printed books, later via the World Data Center ftp server. In the 1990's the first NM stations started to record data at higher resolutions (typically 1 minute) and publish in on their webpages. However, every NM station chose their own format, making it cumbersome to work with this distributed data. In NMDB all European and some neighboring NM stations came together to agree on a common format for high-resolution data and made this available via a centralized database. The goal of NMDB is to make all data from all NM stations available in real-time. The original NMDB network has recently been joined by the Bartol Research Institute (Newark DE, USA), the National Autonomous University of Mexico and the North-West University (Potchefstroom, South Africa). The data is accessible to everyone via an easy to use webinterface, but expert users can also directly access the database to build applications like real-time space weather alerts. Even though SQL databases are used today by most webservices (blogs, wikis, social media, e-commerce), the power of an SQL database has not yet been fully realized by the scientific community. In training courses, we are teaching how to make use of NMDB, how to join NMDB, and how to ensure the data quality. The present status of the extended NMDB will be presented. The consortium welcomes further data providers to help increase the scientific contributions of the worldwide neutron monitor network to heliospheric physics and space weather.

  20. National Ignition Facility (NIF) Neutron time-of-flight (nTOF) Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Lerche, R A; Glebov, V Y; Moran, M J; McNaney, J M; Kilkenny, J D; Eckart, M; Zacharias, R A; Haslam, J J; Clancy, T J; Yeoman, M F; Warwas, D P; Sangster, T C; Stoeckl, C; Knauer, J; Horsfield, C J

    2010-05-13

    The first three of eighteen neutron time-of-flight (nTOF) channels have been installed at the National Ignition Facility (NIF). The role of these detectors includes yield, temperature, and bang time measurements. This article focuses on nTOF data analysis and quality of results obtained for the first set of experiments to use all 192 NIF beams. Targets produced up to 2 x 10{sup 10} 2.45-MeV neutrons for initial testing of the nTOF detectors. Differences in neutron scattering at the OMEGA laser facility where the detectors were calibrated and at NIF result in different response functions at the two facilities. Monte Carlo modeling shows this difference. The nTOF performance on these early experiments indicates the nTOF system with its full complement of detectors should perform well in future measurements of yield, temperature, and bang time.

  1. CERN and the environment

    CERN Multimedia

    Corinne Pralavorio

    2016-01-01

    New webpages answer common questions about CERN and the environment.   One of the new public webpages dedicated to CERN and the environment. Do your neighbours ever ask you about CERN’s environmental impact? And about radiation in particular? If so, the answers to those questions can now be found online on a new set of public webpages dedicated to CERN and the environment. These pages, put together by the Occupational Health, Safety and Environmental Protection (HSE) unit and the groups responsible for CERN's site maintenance, contain a wealth of information on topics linked to the environment, such as biodiversity at CERN, waste management, ionising radiation, and water and electricity consumption. “CERN forms part of the local landscape, with its numerous sites and scientific activities. It’s understandable that people living nearby have questions about the impact of these activities and it’s important that we respond with complete transp...

  2. German visits to CERN

    CERN Multimedia

    2007-01-01

    State secretary to Germany's Federal Ministry of Education and Research, Frieder Meyer-Krahmer, with CERN's Director-General Robert Aymar.On 21 February, Professor Frieder Meyer-Krahmer, State Secretary to Germany's Federal Ministry of Education and Research, came to CERN. He visited the ALICE and ATLAS experiments and the computing centre before meeting the CERN's Director-General, some German physicists and members of the top management. The Minister of Science, Research and the Arts of the Baden-Württemberg regional government, Peter Frankenberg, and CERN's Director-General, Robert Aymar, signing an agreement on education. In the background: Sigurd Lettow, CERN's Director of Finance and Human Resources, and Karl-Heinz Meisel, Rector of the Fachhochschule Karlsruhe. The Minister of Science, Research and the Arts of the Baden-Württemberg regional government, Prof. Peter Frankenberg, visited CERN on 23 February. He was accompanied by the Rector of the Fachhochschule Karlsruhe, Prof. Karl-Heinz Meisel, and b...

  3. Germany at CERN

    CERN Multimedia

    2005-01-01

    From left to right: Maximilian Metzger, CERN's Secretary-General, Hermann Schunck, Director at the German Federal Ministry of Education and Research, and Robert Aymar, CERN's Director-General, talking to Wolfgang Holler from Butting, one of the companies at the "Germany at CERN" exhibition. Far right : Susanne-Corinna Langer-Greipl from BMBF, delegate to the CERN Finance Committee. For three days, CERN's Main Building was transformed into a showcase for German industry. Twenty-nine companies from sectors related to particle physics (electrical engineering, vacuum and low temperature technology, radiation protection, etc.) were here for the ninth "Germany at CERN" exhibition, organised by the German Federal Ministry of Education and Research (BMBF), which gave them the opportunity to meet scientists and administrators from the Laboratory. On 1 March the exhibition was visited by a German delegation headed by Dr Hermann Schunck, Director at BMBF.

  4. Young Artists@ CERN

    CERN Document Server

    2004-01-01

    In view of 50th anniversary of CERN, about 20 young artists will be visiting CERN from 26 to 31 January to learn about the laboratory's research and the mysterious world of particle physics. The impressions they take home will be the main inspiration for the artwork they will then produce for an exhibition to be inaugurated in October 2004 as part of CERN's 50th anniversary celebration. We are looking for scientists who are interested in the Art-Science synergy and who can volunteer to discuss their work at CERN to these young artists during this week (25-31/01). Please contact renilde.vanden.broeck@cern.ch if you are interested. The project is called Young Artists@ CERN and for more information look at this website: http://www.hep.ucl.ac.uk/~andy/CERNart/

  5. CERN Cricket club

    CERN Multimedia

    CERN Cricket club

    2015-01-01

    The CERN Cricket Club 2015 season begins soon, the first net practice is scheduled (weather permitting) for Thursday April 16th, at 18:00! The club is always looking for new players and newcomers will be made very welcome. Anyone who is interested in joining the club should sign up on our web site: http://cern.ch/Club-Cricket/ or turn up for net practice, which takes place each Thursday evening from April 16th (apart from CERN official holidays) until the end of September (starting at 18:00 to around 19:30) at the CERN Prévessin site: http://club-cricket.web.cern.ch/Club-Cricket/CERN-Ground.html The first match will be at home on Sunday, April 19th against Rhone CC from Lyon.

  6. CERN Relay Race

    CERN Multimedia

    CERN Running Club

    2010-01-01

    The CERN relay race will take place around the Meyrin site on Thursday 20 May, starting at 12.15. If possible, please avoid driving on the site during this 20-minute period. If you do meet runners while driving your car, please STOP until they have all passed. Thank you for your cooperation. Details on the route, and how to register your team for the relay race, can be found at: https://espace.cern.ch/Running-Club/CERN-Relay

  7. The CERN PC farm

    CERN Multimedia

    Serge Bellegarde

    2005-01-01

    Housed in the CERN Computer Centre, these banks of computers process and store data produced on the CERN systems. When the LHC starts operation in 2008, it will produce enough data every year to fill a stack of CDs 20 km tall. To handle this huge amount of data, CERN has also developed the Grid, allowing the processing power to be shared between computer centres around the world.

  8. Sharing resources@CERN

    CERN Multimedia

    Maximilien Brice

    2002-01-01

    The library is launching a 'sharing resources@CERN' campaign, aiming to increase the library's utility by including the thousands of books bought by individual groups at CERN. This will improve sharing of information among CERN staff and users. Photo 01: L. to r. Eduardo Aldaz, from the PS division, Corrado Pettenati, Head Librarian, and Isabel Bejar, from the ST division, read their divisional copies of the same book.

  9. Radiation protection at CERN

    OpenAIRE

    Forkel-Wirth, Doris; Roesler, Stefan; Silari, Marco; Streit-Bianchi, Marilena; Theis, Christian; Vincke, Heinz; Vincke, Helmut

    2013-01-01

    This paper gives a brief overview of the general principles of radiation protection legislation; explains radiological quantities and units, including some basic facts about radioactivity and the biological effects of radiation; and gives an overview of the classification of radiological areas at CERN, radiation fields at high-energy accelerators, and the radiation monitoring system used at CERN. A short section addresses the ALARA approach used at CERN.

  10. Time-dependent thermal neutron field in two-region bounded systems

    International Nuclear Information System (INIS)

    A set of solutions of the time-dependent diffusion equation for two-region bounded systems in spherical and cylindrical geometries is presented. Two types of solutions are given for each geometry: the general solution and a solution for the case where the spatial distribution of the thermal neutron flux is constant inside the inner region. These solutions provide the theoretical background for the development of a new method of measuring the thermal neutron macroscopic absorption cross section. The theoretical description of the method worked out for small samples is in good agreement with the experimental results presented. The principles of measuring the neutron transport cross section using small samples and mathematical solutions are described. The possibility of applying a sinusoidally modulated neutron source is presented. Special attention is paid to proper averaging of the thermal neutron diffusion parameters and to the problem of boundary effects. The so-called thermal neutron average dynamic parameters have been used. Results obtained from the modified diffusion theory compare satisfactorily with those obtained form the one-speed transport and P3 theory approximations. (au) (56 refs.)

  11. Study on thermal neutron spectra in reactor moderators by time-of-flight method

    International Nuclear Information System (INIS)

    Prediction of thermal neutron spectra in a reactor core plays very important role in the neutronic design of the reactor for obtaining the accurate thermal group constants. It is well known that the neutron scattering properties of the moderator materials markedly influence the thermal neutron spectra. Therefore, 00 angular dependent thermal neutron spectra were measured by the time-of-flight method in the following moderator bulks 1) Graphite bulk poisoned with boron at the temperatures from 20 to 8000C, 2) Light water bulk poisoned with Cadmium and/or Indium, 3) Light water-natural uranium heterogeneous bulk. The measured results were compared with calculation utilizing Young-Koppel and Haywood scattering model for graphite and light water respectively. On the other hand, a variety of 20% enriched uranium loaded and graphite moderated cores consisting of the different lattice cell in a wide range of the carbon to uranium atomic ratio have been built at Semi-Homogeneous Critical Experimental Assembly (SHE) to perform the critical experiments related to Very High Temperature Reactor (VHTR). The experimental data were for the critical masses in 235U, reactivity worths of experimental burnable poison rods, thorium rods, natural-uranium rods and experimental control rods and kinetic parameters. It is made clear from comparison between measurement and calculation that the accurate thermal group constants can be obtained by use of the Young-Koppel and Haywood neutron scattering models if heterogeneity of reactor core lattices is taken into account precisely. (author)

  12. CERN - better than science fiction!

    CERN Multimedia

    2007-01-01

    From left to right: Allan Cameron (Production Designer), Sam Breckham (Location Manager), James Gillies (Head of Communication at CERN), Jacques Fichet (from the CERN audiovisual service), Rolf Landua (former spokesman of the ATHENA antihydrogen experiment at CERN and Head of CERN's Education Group), Ron Howard, and Renilde Vanden Broeck (CERN press officer).

  13. Neural networks based neutron emissivity tomography at JET with real-time capabilities

    Energy Technology Data Exchange (ETDEWEB)

    Ronchi, E., E-mail: emanuele.ronchi@tsl.uu.s [JET-EFDA, Culham Science Centre, OX14 3DB Abingdon (United Kingdom); Association EURATOM-VR, Department of Physics and Astronomy, Uppsala University, SE-75120 Uppsala (Sweden); Conroy, S.; Andersson Sunden, E.; Ericsson, G.; Gatu Johnson, M.; Hellesen, C.; Sjoestrand, H.; Weiszflog, M. [JET-EFDA, Culham Science Centre, OX14 3DB Abingdon (United Kingdom); Association EURATOM-VR, Department of Physics and Astronomy, Uppsala University, SE-75120 Uppsala (Sweden)

    2010-02-01

    Tomographic reconstruction techniques typically require computationally intensive algorithms which are not suitable for real-time application. This paper describes a framework to perform neutron emissivity tomography at the Joint European Torus (JET) using neural networks with successful results over a broad range of magnetic configurations, heating and fueling schemes. Application times in the mus time scale allows for real-time applicability of the method.

  14. Neural networks based neutron emissivity tomography at JET with real-time capabilities

    International Nuclear Information System (INIS)

    Tomographic reconstruction techniques typically require computationally intensive algorithms which are not suitable for real-time application. This paper describes a framework to perform neutron emissivity tomography at the Joint European Torus (JET) using neural networks with successful results over a broad range of magnetic configurations, heating and fueling schemes. Application times in the μs time scale allows for real-time applicability of the method.

  15. Neutron Moderation in the Oklo Natural Reactor and the Time Variation of alpha

    CERN Document Server

    Lamoreaux, S K

    2003-01-01

    In the analysis of the Oklo (gabon) natural reactor to test for a possible time variation of the fine structure constant alpha, a Maxwell-Boltzmann low energy neutron spectrum was assumed. We present here an analysis where a more realistic spectrum is employed and show that the most recent isotopic analysis of samples implies a non-zero change in alpha, over the last two billion years since the reactor was operating, of \\Delta\\alpha/\\alpha\\geq 2.2\\times 10^{-7} (6\\sigma confidence). Issues regarding the interpretation of the shifts of the low energy neutron resonances are discussed.

  16. Digital image processing for real-time neutron radiography and its applications

    International Nuclear Information System (INIS)

    The present paper describes several digital image processing approaches for the real-time neutron radiography (neutron television-NTV), such as image integration, adaptive smoothing and image enhancement, which have beneficial effects on image improvements, and also describes how to use these techniques for applications. Details invisible in direct images of NTV are able to be revealed by digital image processing, such as reversed image, gray level correction, gray scale transformation, contoured image, subtraction technique, pseudo color display and so on. For real-time application a contouring operation and an averaging approach can also be utilized effectively. (author)

  17. Integrity at CERN

    CERN Document Server

    Department, HR

    2015-01-01

    In the fulfillment of its mission, CERN relies upon the trust and material support of its Member States and partners, and is committed to exercising exemplary stewardship of the resources with which it is entrusted. Accordingly, CERN expects the highest level of integrity from all its contributors (whether members of the personnel, consultants, contractors working on site, or persons engaged in any other capacity at or on behalf of CERN). Integrity is a core value of CERN, defined in the Code of Conduct as “behaving ethically, with intellectual honesty and being accountable for one’s own actions”.

  18. Britain at CERN

    CERN Multimedia

    2000-01-01

    H. E. Mr Christopher Hulse, Ambassador of United Kingdom in Switzerland, CERN Director General Luciano Maiani, Sir David Wright, Chief Executive of British Trade International and Roger Cashmore, CERN Director of research visit the Britain at CERN exhibition. From 14 to 17 November 30 British companies exhibited leading edge technologies at CERN. This is Britain's 18th exhibition at CERN since 1968. Out of the 30 companies, which attended the Britain at CERN exhibition in 1998, 25 have received an order or a contract relating to CERN during the last two years. The exhibition was inaugurated on Tuesday by Sir David Wright, Chief Executive of British Trade International. He was accompanied by H.E. Mr Christopher Hulse CMG, OBE, Her Majesty's Ambassador to Switzerland, and Mr. David Roberts, Deputy Head of Mission and Director of Trade Promotion at the British Embassy in Bern. CERN Director-General, Professor Luciano Maiani, underlined the major contribution of British physicists to CERN, pointing out the fact ...

  19. Dear CERN Computing Community,

    CERN Multimedia

    2003-01-01

    This is to remind you that LXPLUS6 cluster will be switched off on: Friday May 30th 2003 12:00 CET Please start using lxplus.cern.ch now to avoid unnecessary problems at the last minute. Note especially, that telnet and ftp to lxplus.cern.ch are not provided and will not work, instead secure protocols such as ssh and sftp should be used. Also LINUX6 resources in LXBATCH will no longer be available from the same date - Friday May 30th 2003 8:00 CET. See: http://cern.ch/plus/issues.html for other know issues. Vladimir Bahyl CERN/IT/FIO/FS

  20. Dear CERN Computing Community,

    CERN Multimedia

    2003-01-01

    This is to remind you that LXPLUS6 cluster will be switched off on: Friday May 30th 2003 12:00 CETPlease start using lxplus.cern.ch now to avoid unnecessary problems at the last minute. Note especially, that telnet and ftp to lxplus.cern.ch are not provided and will not work, instead secure protocols such as ssh and sftp should be used. Also LINUX6 resources in LXBATCH will no longer be available from the same date - Friday May 30th 2003 8:00 CET. See: http://cern.ch/plus/issues.html for other know issues. Vladimir Bahyl CERN/IT/FIO/FS

  1. Switch of the incoming CERN Telecom operator

    CERN Multimedia

    2004-01-01

    The CERN numbering plan (from 022 767 0000 to 022 767 9999) actually owned by Swisscom will be transferred to Sunrise on the 15th of April 2004 between 6:30 to 7:30. During this action, the following disruptions may happen: • External calls to CERN internal fixed phones may be cut at any time for several minutes. • External calls made from CERN mobiles using "333" may be cut at any time for several minutes. At 7:30, once this action is done, the normal status should be recovered.

  2. CERN exhibition attracts over 100,000 visitors in Belgrade

    CERN Multimedia

    Antonella Del Rosso

    2012-01-01

    “This must be an 'all-time record',” says Ray Lewis, CERN travelling exhibition manager. “In all my time with the various permanent and travelling exhibitions that have taken place locally and within our Member States I have never experienced such figures.”   Zarko Obradovic (left), Serbian Minister of Education, Science and Technology, and Rolf Heuer (right), CERN Director-General, at the CERN travelling exhibition in Belgrade. Indeed, in approximately 20 days of exhibition time about 120,000 people, mainly school visiters and the general public, visited the 100 m2 CERN mini-exhibition. It was set up in the centre of Belgrade in October, in association with the meeting of the Restricted European Committee for Future Accelerators (RECFA). After attending the RECFA meeting, CERN's Director-General Rofl Heuer opened the CERN exhibition on the evening of 19 October. Lectures about CERN were held every afternoon, and two public de...

  3. Neutron Moderation Studied by the Time-Dependent Reaction Rate Method

    International Nuclear Information System (INIS)

    Time dependent neutron spectra have been studied in water, ice and heavy water, using the 5.5-MeV Van de Graaff accelerator at Studsvik as a pulsed neutron source. The change of the spectrum with time,after the injection of the neutrons in the moderator, has been followed by the detection and time analysis of prompt gamma rays which come from the reaction between the flux and the neutron - capturing, spectrum indicators (with known capture cross-section) which have been distributed in small quantities in the moderator. Earlier measurements on the thermalization in water have been extended to the slowing-down region by the use of indium as a spectrum indicator and by measuring with a time resolution of 0.05 μs. The results are in good agreement with the theory for the slowing-down caused by collisions with free protons. The space-dependence near the source of the time-dependent neutron density has been compared with recent theoretical work. In ice the thermalization time constant has been measured. The value obtained, 5 μs, deviates only slightly from the earlier value obtained for water, after correction for the density difference. This implies only a small difference in the integral parameters of the scattering law for the two states of water. Time-dependent reaction rate curves have also been measured for heavy water, using a volume of 900 l and indium,cadmium and gadolinium as indicators. Von Dardel's trial function for the time-dependent density during slowing down has been verified. The thermalization proceeds with a time constant of 33 μs and has been completed after 200 μs. (author)

  4. Time correlation of cosmic-ray-induced neutrons and gamma rays at sea level

    Energy Technology Data Exchange (ETDEWEB)

    Miloshevsky, G., E-mail: gennady@purdue.edu; Hassanein, A.

    2014-02-11

    The neutrons and gamma rays produced by cosmic ray interactions in spallation and evaporation processes of air nuclei are time-correlated. The occurrence of their counts in a fixed time interval is not a random (Poisson) distribution, but rather time-correlated bursts of counts. A computational model is developed to explore time correlations of cosmic-ray-induced background of neutrons and gammas at sea level. Their lifetimes in air showers, multiplicity distributions, coincidence count statistic, and excess variance are analyzed. The effects of latitude and area size on multiplicity and coincidence distributions are also studied. The coincidence count distributions and Feynman-Y statistic are used to reveal the duration of spallation processes and properties of multiplying media. It is found that the coincidence count distribution in fixed time intervals deviates from a Poisson distribution. The Feynman-Y is about an order of magnitude greater for gammas than that for neutrons. For both neutrons and gammas, the duration of time-correlated multiplying processes in air showers is ∼250 µs.

  5. Time correlation of cosmic-ray-induced neutrons and gamma rays at sea level

    International Nuclear Information System (INIS)

    The neutrons and gamma rays produced by cosmic ray interactions in spallation and evaporation processes of air nuclei are time-correlated. The occurrence of their counts in a fixed time interval is not a random (Poisson) distribution, but rather time-correlated bursts of counts. A computational model is developed to explore time correlations of cosmic-ray-induced background of neutrons and gammas at sea level. Their lifetimes in air showers, multiplicity distributions, coincidence count statistic, and excess variance are analyzed. The effects of latitude and area size on multiplicity and coincidence distributions are also studied. The coincidence count distributions and Feynman-Y statistic are used to reveal the duration of spallation processes and properties of multiplying media. It is found that the coincidence count distribution in fixed time intervals deviates from a Poisson distribution. The Feynman-Y is about an order of magnitude greater for gammas than that for neutrons. For both neutrons and gammas, the duration of time-correlated multiplying processes in air showers is ∼250 µs

  6. Rietveld refinement with time-of-flight powder diffraction data from pulsed neutron sources

    International Nuclear Information System (INIS)

    The recent development of accelerator-based pulsed neutron sources has led to the widespread use of the time-of-flight technique for neutron powder diffraction. The properties of the pulsed source make possible unusually high resolution over a wide range of d spacings, high count rates, and the ability to collect complete data at fixed scattering angles. The peak shape and other instrument characteristics can be accurately modelled, which make Rietveld refinement possible for complex structures. In this paper we briefly review the development of the Rietveld method for time-of-flight diffraction data from pulsed neutron sources and discuss the latest developments in high resolution instrumentation and advanced Rietveld analysis methods. 50 refs., 12 figs., 14 tabs

  7. Calculation of the reactor neutron time of flight spectrum by convolution technique

    International Nuclear Information System (INIS)

    It is a very complex and time-consuming process to simulate the nuclear reactor neutron spectrum from the reactor core to the export channel by applying a Monte Carlo program. This paper presents a new method to calculate the neutron spectrum by using the convolution technique which considers the channel transportation as a linear system and the transportation scattering as the response function. It also applies Monte Carlo Neutron and Photon Transport Code (MCNP) to simulate the response function numerically. With the application of convolution technique to calculate the spectrum distribution from the core to the channel, the process is then much more convenient only with the simple numerical integral numeration. This saves computer time and reduces some trouble in re-writing of the MCNP program. (general)

  8. Crosscorrelation techniques in neutron polarisation analysis time-of-flight studies

    International Nuclear Information System (INIS)

    A method of performing time-of-flight measurements on a neutron polarisation analysis instrument is described. The method involves a crosscorrelation technique in which the neutron beam polarisation prior to the scattering sample is modulated by a neutron spin flipper according to a predetermined pseudo random sequence. It is shown that the final crosscorrelation of the measured count rate at the detector with the pseudo random sequence yields a time-of-flight spectrum which is proportional to the difference between the spin flip and non spin flip scattering cross-sections of the sample. Implementation of the technique and an example of its use are discussed. It is also shown that in a simple form the crosscorrelation technique is useful in providing discrimination against inelastic scattering. (author)

  9. Chasseur de rayons cosmiques au CERN

    CERN Multimedia

    Brouet, Anne-Muriel

    2003-01-01

    Alvaro de Rújula swims every day in the macro and the microspace. At CERN since 25 years, he shares his time between his appointment as a professor in Boston and his researches to satisfy his scientific curiosity

  10. Study of time response of fission neutrons induced apoptosis in murine thymocytes and its molecular mechanism

    International Nuclear Information System (INIS)

    Objective:To study the time response of fission neutrons induced apoptosis in murine thymocytes with 60Co γ-rays as the reference radiation and to investigate preliminarily its molecular mechanism. Methods: Apoptosis induction was detected by means of DNA gel electrophoresis, morphologic assay, flow cytometric (FCM) analysis and diphenylamine(DPA) method respectively. p53 and bcl-2 gene expressions were studied by dot hybridization with digoxigenin labelled probes. Results: When mice was exposed to 2.5 Gy of fission neutrons, DNA ladders of thymocytes were detected at different time points during 2-24 hours post-irradiation. Thymocytes with typical morphological characteristics of apoptosis were also observed. Time response curves were obtained with methods of morphologic assay, FCM analysis and DPA method. The percentage of thymocytes undergoing apoptosis steeply increased during the first 6 hours post-irradiation,reached the peak levels at 8-10 hours,began to decrease 12 hours later and significantly decreased by 24 hours as compared with the level at 4-12 hours (P < 0.05) but was still slightly higher than the normal level. Similar curves were obtained by using three different methods. Time response curve after exposure to 5.0 Gy of γ-irradiation was characterized by an initial slow increase in the number of apoptotic thymocytes during the first 6 hours post-irradiation. In addition, DNA ladders were not detected at 24 hours post-irradiation. After exposure to 2.5 Gy of fission neutrons irradiation, p53 gene expression at 2, 4, 12 and 24 hours post-irradiation were obviously higher than in control (P<0.05 or P<0.01),while bcl-2 gene expression at different time points during 2-24 hours post-irradiation decreased obviously (P<0.01)in comparison with non-irradiated control. Conclusions: Apoptosis of murine thymocytes can be induced in mice exposed to 2.5 Gy of fission neutrons. The rules of time response after fission neutrons irradiation for 2.5 Gy is similar

  11. Neutron measurements with Time-Resolved Event-Counting Optical Radiation (TRECOR) detector

    Science.gov (United States)

    Brandis, M.; Vartsky, D.; Dangendorf, V.; Bromberger, B.; Bar, D.; Goldberg, M. B.; Tittelmeier, K.; Friedman, E.; Czasch, A.; Mardor, I.; Mor, I.; Weierganz, M.

    2012-04-01

    Results are presented from the latest experiment with a new neutron/gamma detector, a Time-Resolved, Event-Counting Optical Radiation (TRECOR) detector. It is composed of a scintillating fiber-screen converter, bending mirror, lens and Event-Counting Image Intensifier (ECII), capable of specifying the position and time-of-flight of each event. TRECOR is designated for a multipurpose integrated system that will detect Special Nuclear Materials (SNM) and explosives in cargo. Explosives are detected by Fast-Neutron Resonance Radiography, and SNM by Dual Discrete-Energy gamma-Radiography. Neutrons and gamma-rays are both produced in the 11B(d,n+γ)12C reaction. The two detection modes can be implemented simultaneously in TRECOR, using two adjacent radiation converters that share a common optical readout. In the present experiment the neutron detection mode was studied, using a plastic scintillator converter. The measurements were performed at the PTB cyclotron, using the 9Be(d,n) neutron spectrum obtained from a thick Be-target at Ed ~ 13 MeV\\@. The basic characteristics of this detector were investigated, including the Contrast Transfer Function (CTF), Point Spread Function (PSF) and elemental discrimination capability.

  12. Neutron time-of-flight spectroscopy measurement using a waveform digitizer

    Science.gov (United States)

    Liu, Long-Xiang; Wang, Hong-Wei; Ma, Yu-Gang; Cao, Xi-Guang; Cai, Xiang-Zhou; Chen, Jin-Gen; Zhang, Gui-Lin; Han, Jian-Long; Zhang, Guo-Qiang; Hu, Ji-Feng; Wang, Xiao-He

    2016-05-01

    The photoneutron source (PNS, phase 1), an electron linear accelerator (linac)-based pulsed neutron facility that uses the time-of-flight (TOF) technique, was constructed for the acquisition of nuclear data from the Thorium Molten Salt Reactor (TMSR) at the Shanghai Institute of Applied Physics (SINAP). The neutron detector signal used for TOF calculation, with information on the pulse arrival time, pulse shape, and pulse height, was recorded by using a waveform digitizer (WFD). By using the pulse height and pulse-shape discrimination (PSD) analysis to identify neutrons and γ-rays, the neutron TOF spectrum was obtained by employing a simple electronic design, and a new WFD-based DAQ system was developed and tested in this commissioning experiment. The DAQ system developed is characterized by a very high efficiency with respect to millisecond neutron TOF spectroscopy. Supported by Strategic Priority Research Program of the Chinese Academy of Science(TMSR) (XDA02010100), National Natural Science Foundation of China(NSFC)(11475245,No.11305239), Shanghai Key Laboratory of Particle Physics and Cosmology (11DZ2260700)

  13. Monitoring Short-term Cosmic-ray Spectral Variations Using Neutron Monitor Time-delay Measurements

    Science.gov (United States)

    Ruffolo, D.; Sáiz, A.; Mangeard, P.-S.; Kamyan, N.; Muangha, P.; Nutaro, T.; Sumran, S.; Chaiwattana, C.; Gasiprong, N.; Channok, C.; Wuttiya, C.; Rujiwarodom, M.; Tooprakai, P.; Asavapibhop, B.; Bieber, J. W.; Clem, J.; Evenson, P.; Munakata, K.

    2016-01-01

    Neutron monitors (NMs) are ground-based detectors of cosmic-ray showers that are widely used for high-precision monitoring of changes in the Galactic cosmic-ray (GCR) flux due to solar storms and solar wind variations. In the present work, we show that a single neutron monitor station can also monitor short-term changes in the GCR spectrum, avoiding the systematic uncertainties in comparing data from different stations, by means of NM time-delay histograms. Using data for 2007-2014 from the Princess Sirindhorn Neutron Monitor, a station at Doi Inthanon, Thailand, with the world’s highest vertical geomagnetic cutoff rigidity of 16.8 GV, we have developed an analysis of time-delay histograms that removes the chance coincidences that can dominate conventional measures of multiplicity. We infer the “leader fraction” L of neutron counts that do not follow a previous neutron count in the same counter from the same atmospheric secondary, which is inversely related to the actual multiplicity and increases for increasing GCR spectral index. After correction for atmospheric pressure and water vapor, we find that L indicates substantial short-term GCR spectral hardening during some but not all Forbush decreases in GCR flux due to solar storms. Such spectral data from Doi Inthanon provide information about cosmic-ray energies beyond the Earth’s maximum geomagnetic cutoff, extending the reach of the worldwide NM network and opening a new avenue in the study of short-term GCR decreases.

  14. Indigenous design and development of multiPSD array for time of flight neutron spectrometer

    Science.gov (United States)

    Desai, Shraddha S.; Devan, Shylaja; Das, Amrita; Patkar, S. M.; Rao, Mala N.

    2016-05-01

    Time of Flight neutron Spectrometer for inelastic neutron scattering studies is being commissioned at Dhruva reactor. Neutron pulse tagging is carried out using the Fermi chopper. Scattered neutrons at maximum possible scattered solid angle are needed to be detected along with the time information at detector. Precise and efficient detection system is essential for measurement of spatial and temporal distribution. Detection area is optimized to cover an angle of 70° in horizontal direction and 23° in vertical direction. Position sensitive detectors (PSDs) are designed with judicial use of precious 3He gas and a few PSDs with BF3 gas as suitable alternative for 3He gas. An array of vertically arranged 1 m long, 50 PSDs, covers the arc length of 2.5 m and detection area 2.5 m2. The design of the BF3 PSDs is supported by investigations on the gas purity, fill gas pressure, drift region, drift field and neutron absorption in cathode wall. Design details and performance of the PSDs are presented in the paper.

  15. Preliminary energy-filtering neutron imaging with time-of-flight method on PKUNIFTY: A compact accelerator based neutron imaging facility at Peking University

    Science.gov (United States)

    Wang, Hu; Zou, Yubin; Wen, Weiwei; Lu, Yuanrong; Guo, Zhiyu

    2016-07-01

    Peking University Neutron Imaging Facility (PKUNIFTY) works on an accelerator-based neutron source with a repetition period of 10 ms and pulse duration of 0.4 ms, which has a rather low Cd ratio. To improve the effective Cd ratio and thus improve the detection capability of the facility, energy-filtering neutron imaging was realized with the intensified CCD camera and time-of-flight (TOF) method. Time structure of the pulsed neutron source was firstly simulated with Geant4, and the simulation result was evaluated with experiment. Both simulation and experiment results indicated that fast neutrons and epithermal neutrons were concentrated in the first 0.8 ms of each pulse period; meanwhile in the period of 0.8-2.0 ms only thermal neutrons existed. Based on this result, neutron images with and without energy filtering were acquired respectively, and it showed that detection capability of PKUNIFTY was improved with setting the exposure interval as 0.8-2.0 ms, especially for materials with strong moderating capability.

  16. Towards the CERN of tomorrow

    CERN Multimedia

    2009-01-01

    The Council working group on the geographical and scientific enlargement of CERN met for the first time during the week of 9 March. It was a good meeting, setting the pace for what promises to be a very important process. A timetable for meetings and consultations has been put in place, and all being well we can look forward to recommendations being made at the December meeting of Council this year. Since my talk to the CERN staff in January, much has been made of my statement that nothing is off the table, so I’d like to make it clear what that means. The CERN Convention is required reading for my job. It’s a remarkably concise and prescient document, as relevant today as it was when it was written over half a century ago. If you haven’t already done so, I strongly recommend that you read it. The Convention states that the Organization shall "provide for collaboration among European States", and goes on to say that CERN should ...

  17. Maintenance of the CERN telephone exchanges

    CERN Multimedia

    TS Department

    2008-01-01

    Maintenance work will be carried out on the CERN telephone exchanges between 8 p.m. and midnight on 3 December. During this time, the fixed-line telephone and audio-conference services may be disrupted. However, the CCC and the Fire Brigade will be reachable at all times. Mobile telephone services (GSM) will not be affected by this work. For further details please contact mailto:Netops@cern.ch.

  18. Maintenance of the CERN telephone exchanges

    CERN Multimedia

    TS Department

    2008-01-01

    Maintenance work will be carried out on the CERN telephone exchanges between 8 p.m. and midnight on 3 December. During this time, the fixed-line telephone and audio-conference services may be disrupted. However, the CCC and the Fire Brigade will be reachable at all times. Mobile telephone services (GSM) will not be affected by this work. For further details please contact Netops@cern.ch.

  19. Optimal timing of neutron irradiation for boron neutron capture therapy after intravenous infusion of sodium borocaptate in patients with glioblastoma

    International Nuclear Information System (INIS)

    Purpose: A cooperative study in Europe and Japan was conducted to determine the pharmacokinetics and boron uptake of sodium borocaptate (BSH: Na2B12H11SH), which has been introduced clinically as a boron carrier for boron neutron capture therapy in patients with glioblastoma. Methods and Materials: Data from 56 patients with glioblastoma who received BSH intravenous infusion were retrospectively reviewed. The pharmacokinetics were evaluated in 50 patients, and boron uptake was investigated in 47 patients. Patients received BSH doses between 12 and 100 mg/kg of body weight. For the evaluation, the infused boron dose was scaled linearly to 100 mg/kg BSH. Results: In BSH pharmacokinetics, the average value for total body clearance, distribution volume of steady state, and mean residence time was 3.6±1.5 L/h, 223.3±160.7 L, and 68.0±52.5 h, respectively. The average values of the boron concentration in tumor adjusted to 100 mg/kg BSH, the boron concentration in blood adjusted to 100 mg/kg BSH, and the tumor/blood boron concentration ratio were 37.1±35.8 ppm, 35.2±41.8 ppm, and 1.53±1.43, respectively. A good correlation was found between the logarithmic value of Tadj and the interval from BSH infusion to tumor tissue sampling. About 12-19 h after infusion, the actual values for Tadj and tumor/blood boron concentration ratio were 46.2±36.0 ppm and 1.70±1.06, respectively. The dose ratio between tumor and healthy tissue peaked in the same interval. Conclusion: For boron neutron capture therapy using BSH administered by intravenous infusion, this work confirms that neutron irradiation is optimal around 12-19 h after the infusion is started

  20. Collide@CERN ProHelvetia Public Lecture

    CERN Document Server

    CERN. Geneva; Heuer, Rolf; Mr. de Diesbach, Simon; Mr. Dubois, Marc; Ms. Perrenoud, Laura; Mr. Vust, Michel; Mrs. Bello, Monica

    2015-01-01

    You are very warmly invited to the opening presentation of Fragment.In’s residency at CERN. Fragment.In are the winners of Collide@CERN ProHelvetia, a collective formed by Laura Perrenoud, Simon de Diesbach, and Marc Dubois. They will present their artistic work along with their CERN scientific inspiration partner, who will present his/her work on Science. In their proposal, Fragment.In has a unique, original and creative approach to data visualization. We look forward to having them at CERN. Collide@CERN is the three month residency programme providing artists with time and space to reflect, research and renew their artistic practice.

  1. Is timing noise important in the gravitational wave detection of neutron stars?

    OpenAIRE

    Jones, D. I.

    2004-01-01

    In this paper we ask whether the phenomenon of timing noise long known in electromagnetic pulsar astronomy is likely to be important in gravitational wave (GW) observations of spinning-down neutron stars. We find that timing noise is strong enough to be of importance only in the young pulsars, which must have larger triaxialities than theory predicts for their GW emission to be detectable. However, assuming that their GW emission is detectable, we list the pulsars for which timing noise is im...

  2. Experimental Tests of Neutron Shielding for the ATLAS Forward Region

    CERN Document Server

    Pospísil, S; Cechák, T; Cermák, P; Jakubek, J; Kluson, J; Konícek, J; Kubasta, J; Linhart, V; Sinor, M; Leroy, C; Dolezal, Z; Leitner, R; Lukianov, G A; Soustruznik, K; Lokajícek, M; Némécek, S; Pálla, G; Sodomka, J

    1999-01-01

    Experimental tests devoted to the optimization of the neutron shielding for the ATLAS forward region were performed at the CERN-PS with a 4 GeV/c proton beam. Spectra of fast neutrons, slow neutrons and gamma rays escaping a block of iron (40$\\times$40$\\times$80 cm$^3$) shielded with different types of neutron and gamma shields (pure polyethylene - PE, borated polyethylene - BPE, lithium filled polyethylene - LiPE, lead, iron) were measured by means of plastic scintillators, a Bonner spectrometer, a HPGe detector and a slow neutron detector. Effectiveness of different types of shielding agaisnt neutrons and $\\gamma$-rays were compared. The idea of a segmented outer layer shielding (iron, BPE, iron, LiPE) for the ATLAS Forward Region was also tested.

  3. Romanian Visit to CERN

    CERN Multimedia

    2001-01-01

    Romanian Minister for Foreign Affairs, Mr Mircea Dan Geoana, visited CERN on 30 March to discuss collaboration between his country and the Laboratory. Above, Mr Dan Geoana signs the visitors' book in the presence of CERN Director General Luciano Maiani and Mrs Anda Flip, Ambassador and permanent representative of Romania at the United Nations.

  4. CERN's Early History Revisited

    CERN Multimedia

    Schopper, Herwig Franz; Krige, Gerhard John

    2005-01-01

    As a member of the group of historians charged to write the history of the founding of CERN, John Krige particularly underlines the important role I.I. Rabi played. The first author, former Director General of CERN add a few comments. S.A. Khan gives precisions about the role played by E. Amaldi and P. Auger; then J. Krige replies

  5. ESO: The CERN Years

    CERN Multimedia

    Schaeffer, A

    2012-01-01

    In 1970, CERN and ESO signed a collaboration agreement for the construction of the Observatory’s first telescope. That same year, ESO’s Telescope Division and Sky Atlas laboratory settled on the CERN site in Meyrin. Let’s turn back to the beginnings of this lasting and fruitful alliance.

  6. Punctualizaciones del CERN

    CERN Multimedia

    2002-01-01

    "Viene de la pagina anterior. Puntualizaciones del CERN. La valoracion que me merece la aprobacion en el Consejo de Ministros el 24 de mayo de un acuerdo de colaboracion entre el MCYT y el CERN para el proyecto de neutrinos al Gran Sasso es positiva" (1 page).

  7. Integration of CERN staff

    CERN Multimedia

    1965-01-01

    An example of the integration of CERN staff in the neighbouring communes is provided by the hamlet of Bugnon at St-Genis-Pouilly (Ain), FRance. The CERN installation on the Swiss site are visible on the left in the background. Behind them the Saleve mountain in Haute-Savoie.

  8. Child Care at CERN

    CERN Document Server

    CERN, Child Care Initiative

    2008-01-01

    This is a document summarizing a survey of child care needs of CERN staff and users which was performed in February 2008 by the CERN Child Care Initiative. The document presents the analysis of this data. Conclusions on the minimal facilities size are derived and possible funding source at the European Union are discussed.

  9. The CERN Accelerator School

    CERN Multimedia

    2016-01-01

    Introduction to accelerator physics This course will take place in Budapest, Hungary, from 2 to 14 October 2016. It is now open for registration and further information can be found at: http://cas.web.cern.ch/cas/Hungary2016/Hungary-advert.html and http://indico.cern.ch/event/532397/.

  10. CERN and the LHC

    CERN Multimedia

    Cramer, J G

    1992-01-01

    CERN, a high-energy physics laboratory in Europe, is planning to build a more powerful particle accelerator, the Large Hadronic Collider. The US spreads its accelerators around the country while most of Europe's research is conducted at and around CERN.

  11. CERN openlab Open Day

    CERN Multimedia

    Purcell, Andrew Robert

    2015-01-01

    The CERN openlab Open Day took place on 10 June, 2015. This was the first in a series of annual events at which research and industrial teams from CERN openlab can present their projects, share achievements, and collect feedback from their user communities.

  12. UK Mission to CERN

    CERN Multimedia

    2004-01-01

    At the end of June, nine experts from UK industry visited CERN to study techniques for developing distributed computing systems and to look at some specific applications. In a packed three-day programme, almost 40 CERN experts presented a comprehensive survey of achievements.

  13. Boron carbide based solid state neutron detectors: the effects of bias and time constant on detection efficiency

    International Nuclear Information System (INIS)

    Neutron detection in thick boron carbide(BC)/n-type Si heterojunction diodes shows a threefold increase in efficiency with applied bias and longer time constants. The improved efficiencies resulting from long time constants have been conclusively linked to the much longer charge collection times in the BC layer. Neutron detection signals from both the p-type BC layer and the n-type Si side of the heterojunction diode are observed, with comparable efficiencies. Collectively, these provide strong evidence that the semiconducting BC layer plays an active role in neutron detection, both in neutron capture and in charge generation and collection.

  14. FASTBUS data acquisition system for neutron time-of-flight measurements

    International Nuclear Information System (INIS)

    The design of a new data acquisition system for the Weapons Neutron Research Facility is based on the FASTBUS system hosted by DEC computers. System and FASTBUS configurations are discussed. Modules unique to pulsed time-of-flight measurements are presented

  15. France at CERN

    CERN Multimedia

    2001-01-01

    From 19 to 22 June, for the 8th edition of France at CERN, 31 French companies presented their latest technology to the Laboratory. Demonstrating the latest in French technology during France at CERN. The France at CERN exhibition was inaugurated by Mr. Bernard Frois, Director of the Department Energy, Transport, Environment and Natural Resources at the Technology Directorate of the Ministry of Research. 'France is happy to be a Member of CERN, which is a successful example of the construction of scientific Europe,' he declared during the inauguration, 'this exhibition is an excellent opportunity to put fundamental research and advanced technology in contact.' Mr. Philippe Petit, French Ambassador to Switzerland, and Mr. Alexandre Defay, technical adviser of the Minister of Research, were also present to represent France and its industry. Representing CERN at the 19 June opening of the exhibition was Claude Detraz, who said, 'I hope that this exhibition will make it possible to weave stronger links between ...

  16. CERN in the park

    CERN Multimedia

    2002-01-01

    CERN will be the centre of debate at a 'Café scientifique' on Monday 29 April. The aim of the Cafés scientifiques, which are organised by the association of Bancs Publics, is to kindle discussion between ordinary people and specialists in a scientific field. This Monday, Maurice Bourquin, President of the CERN Council, Hans Hoffmann, Director of Technology Transfer and Scientific Computing at CERN, Gilbert Guignard, a physicist at CERN, and Ruhal Floris, who teaches mathematical didactics at the University of Geneva, will explain the usefulness and contributions to science of the world's biggest laboratory for particle physics. What is CERN for? Monday 29 April at 18.30 Musée d'histoire des sciences, Geneva (in the park Perle du Lac) Entry free Wine and buffet after the discussion

  17. Romanian President Visits CERN

    CERN Multimedia

    2001-01-01

    Director General Luciano Maiani watches as Romanian President Ion Iliescu signs the CERN guest book. On Friday the 12th of October, Romanian President Ion Iliescu arrived at CERN and was warmly greeted by Director General Luciano Maiani at the steps of building 500. After initial greetings and a general presentation of the laboratory, President Iliescu and his entourage embarked on a whistle stop tour of the CERN facilities. They visited the CMS magnet assembly hall and civil engineering work where presentations were made by CMS spokesperson Michel Della Negra and the ATLAS Tile Calorimeter where the president was introduced to Romanian physicists working here at CERN. Michel Della Negra explains some of the general principles behind CMS to President Iliescu during his visit last week. The Romanian teams working on CERN projects make very visible contributions, for example to the construction of the ATLAS experiment and to the preparation of its eventual scientific exploitation. 'Those of us on the ATLAS ...

  18. CERN Mobility Survey

    CERN Multimedia

    GS Department

    2011-01-01

    The Institute of Shipping and Transport of the University of the Aegean and the National Technical University of Athens are partners with CERN in a study of mobility patterns between and within the CERN sites and to that effect have realized a mobility survey dedicated to the CERN community.         The study aims to understand: How you presently get around the CERN sites; What problems you encounter regarding mobility; What your needs are; What improvements you’d like to see; What measures you would like to see implemented most. The replies we receive will enable us to define a general policy promoting the diversity of mobility at CERN and to establish and quantify the strategic actions to be implemented for both the short and medium term. The objectives of the transport mobility plans are to: Facilitate mobility within and between the CERN sites by identifying adequate solutions in response to individual ...

  19. Lectures for CERN pensioners

    CERN Multimedia

    GS Department

    2009-01-01

    The CERN Medical Service and the Pensioners Association are pleased to invite CERN pensioners to a series of lectures given by professors and specialists from the Teaching Hospitals and the Faculty of Medicine of the University of Geneva on the following topic: PROMOTION OF OPTIMUM BRAIN AGEING The lectures will take place in the Main CERN Auditorium (Building 60) from 2.30 p.m. to 4.30 p.m. on the following dates: Thursday 15 January 2009: Diagnosing and treating Alzheimer’s disease Pr Gabriel GOLD Wednesday 25 February 2009: What is the brain reserve? Speaker’s name to be announced at a later date. The lectures will be given in French, with transparencies in English, and will be followed by a wide-ranging debate with the participants. CERN Medical Service - Pensioners Association - CERN-ESO (GAC-EPA)

  20. Wide dynamic range neutron flux monitor having fast time response for the Large Helical Device

    International Nuclear Information System (INIS)

    A fast time response, wide dynamic range neutron flux monitor has been developed toward the LHD deuterium operation by using leading-edge signal processing technologies providing maximum counting rate up to ∼5 × 109 counts/s. Because a maximum total neutron emission rate over 1 × 1016 n/s is predicted in neutral beam-heated LHD plasmas, fast response and wide dynamic range capabilities of the system are essential. Preliminary tests have demonstrated successful performance as a wide dynamic range monitor along the design

  1. Investigation of the structure of ettringite by time-of-flight neutron powder diffraction techniques

    International Nuclear Information System (INIS)

    The crystalline structure of ettringite, Ca6[Al(OH)6]2(SO4)3.∼26H2O, was investigated using high-resolution time-of-flight neutron powder diffraction techniques. The powder diffraction data were subjected to Rietveld crystal structure refinement. The resultant ettringite crystal structure confirmed the positions of Ca, Al, and S atoms while permitting a more precise determination of the locations of O and H atomic positions than in previous X-ray and neutron diffraction studies. A discussion of the ettringite hydrogen bonding network is presented, illustrating the role of hydrogen bonding in the stabilization of the ettringite structure

  2. Study on neutron diffusion and time dependence heat ina fluidized bed nuclear reactor

    International Nuclear Information System (INIS)

    The purpose of this work is to model the neutron diffusion and heat transfer for a Fluidized Bed Nuclear Reactor and its solution by Laplace Transform Technique with numerical inversion using Fourier Series. Also Gaussian quadrature and residues techniques were applied for numerical inversion. The neutron transport, diffusion, and point Kinetic equation for this nuclear reactor concept are developed. A matricial and Taylor Series methods are proposed for the solution of the point Kinetic equation which is a time scale problem of Stiff type

  3. A time-of-flight neutron reflectometer for surface and interfacial studies

    International Nuclear Information System (INIS)

    A time-of-flight neutron reflectometer constructed for surface and interfacial studies, and installed at the ISIS pulsed neutron source, is described. One of its important design features is its inclined incident beam, since this allows both liquid and solid surface phenomena to be investigated. Measurements are presented to show the performance of the instrument, and new representative results, which include studies of liquid surfaces, Langmuir-Blodgett films, and thin film multilayers, are included as illustrations of the scientific potential of the method. (author)

  4. A silicon photomultiplier readout for time of flight neutron spectroscopy with γ-ray detectors

    International Nuclear Information System (INIS)

    The silicon photomultiplier (SiPM) is a recently developed photosensor used in particle physics, e.g., for detection of minimum ionizing particles and/or Cherenkov radiation. Its performance is comparable to that of photomultiplier tubes, but with advantages in terms of reduced volume and magnetic field insensitivity. In the present study, the performance of a gamma ray detector made of an yttrium aluminum perovskite scintillation crystal and a SiPM-based readout is assessed for use in time of flight neutron spectroscopy. Measurements performed at the ISIS pulsed neutron source demonstrate the feasibility of γ-detection based on the new device.

  5. Neutron moderation in the Oklo natural reactor and the time variation of α

    Science.gov (United States)

    Lamoreaux, S. K.; Torgerson, J. R.

    2004-06-01

    In previous analyses of the Oklo (Gabon) natural reactor to test for a possible time variation of the fine-structure constant α, a Maxwell-Boltzmann low energy neutron spectrum was assumed. We present here an analysis where a more realistic spectrum is employed and show that the most recent isotopic analysis of samples implies a decrease in α, over the last 2×109 years since the reactor was operating, of (αpast-αnow)/α⩾4.5×10-8 (6σ confidence). Issues regarding the interpretation of the shifts of the low energy neutron absorption resonances are discussed.

  6. Time behaviour of the neutron flux at reactivity changes close to criticality

    International Nuclear Information System (INIS)

    In the determination of the control rod positions for which a nuclear power reactor becomes critical, the time behaviour of the neutron flux is usually observed. This time behaviour has been calculated in the point reactor approximation using six groups of delayed neutrons. The results show that, from the shape of the obtained curves, it is difficult to draw any certain conclusions whether the reactor is supercritical or not, if the observation time is as short as 10-30 s. Determination of the doubling time seems to be a good help in deciding when to decrease the steps in the control rod movements and increase the observation time in order to avoid unintentional criticality. (author)

  7. CERN Access Cards and Access Authorisations

    CERN Multimedia

    2003-01-01

    From the 01/05/2003, all problems relating to access cards and refusal of access to any zone, building or experiment within CERN must be addressed to the Centrale de Surveillance des Accès (CSA building 120) on 78877 or send an e-mail to Access.Surveillance@cern.ch. The responsibles for CERN access control have put into place a procedure with the CSA, Service Enregistrement and the Technical Control Room, to make sure that all problems get resolved in a proper and timely manner.

  8. Simulations of a new detection concept for high-energy neutrons based on timing RPCs

    International Nuclear Information System (INIS)

    In this manuscript we present a novel concept for the detection of relativistic neutrons (between 100 MeV and 1 GeV) based on Resistive Plate Chambers (RPCs). Its principle relies on the detection of charged particles created in hadronic showers induced by the incoming neutrons on the detector constituent materials. The presented design solely considers glass plates as converters for neutron detection while simultaneously delimiting the active gas. For the optimization of a large area detector based on RPCs, simulations using the Virtual Monte Carlo framework FairRoot have been performed. The resulting detector is designed using timing RPC modules, each with 5 gas gaps, that are sequentially grouped, reaching an efficiency for one neutron detection higher than 90%. We show a systematic study on the counter performance as a function of the thickness of the glass plates, and present the design of a prototype to be tested with quasi-monoenergetic neutrons of energies ranging between 200 MeV and 1.5 GeV in the upcoming future

  9. Study of elastic and inelastic neutron cross-sections using time of flight technique

    International Nuclear Information System (INIS)

    High precision neutron scattering data has become increasingly important in the development of nuclear reactors and accelerator systems, astrophysics and space system design, radiation therapy and isotope production, and for shielding considerations. Previous evaluations of the neutron cross-section standards were completed in 1987 and disseminated as NEANDC/INDC and other databases. R-matrix model fits for the light elements and non-model least-squares fits for the heavy elements were the basis of the combined fits for all of the data. Some important reactions and constants are not considered standards, but assist greatly in the determination of the standard cross-sections and reduce their uncertainties. The focus of the present work is to measure elastic and inelastic neutron differential scattering cross-sections for 23Na using Time of Flight Technique for a range of energies with a high accuracy level

  10. Calculation of the reactor neutron time of flight spectrum by convolution technique

    Institute of Scientific and Technical Information of China (English)

    Cheng Jin-Xing; Ouyang Xiao-Ping; Zheng Yi; Zhang An-Hui; Ouyang Mao-Jie

    2008-01-01

    It is a very complex and tlme-consuming process to simulate the nuclear reactor neutron spectrum from the reactor core to the export channel by applying a Monte Carlo program. This paper presents a new method to calculate the neutron spectrum by using the convolution technique which considers the channel transportation as a linear system and the transportation scattering as the response function. It also applies Monte Carlo Neutron and Photon Transport Code (MCNP) to simulate the response function numerically. With the application of convolution technique to calculate thespectrum distribution from the core to the channel, the process is then much more convenient only with the simple numerical integral numeration. This saves computer time and reduces some trouble in re-writing of the MCNP program.

  11. A Dead Time Correction for Overlapped Pulse Signals for a Thermal Neutron Coincidence Counter System

    International Nuclear Information System (INIS)

    A typical well-type thermal neutron counter uses many He-3 proportional counter neutron detectors to enhance its measurement efficiency. Such, He-3 detectors are grouped with several other groups to make one output signal. Then the group signals are connected to shift register coincidence electronics using an OR gate device. But a loss of pulse signals occurs in an OR gate device because a simultaneous pulse signal is recognized as one pulse signal. This paper describes the development of a new circuit that processes overlapped pulse signals and the effect of the dead time with an OR gate device of an ACP Safeguards Neutron Counter (ASNC) for an Advanced Spent Fuel Conditioning Process (ACP)

  12. Monte Carlo calculation of neutron generation time in critical reactor and subcritical reactor with an external source

    International Nuclear Information System (INIS)

    The neutron generation time Λ plays an important role in the reactor kinetics. However, it is not straightforward nor standard in most continuous energy Monte Carlo codes which are able to calculate the prompt neutron lifetime lp directly. The difference between Λ and lp are sometimes very apparent. As very few delayed neutrons are produced in the reactor, they have little influence on Λ. Thus on the assumption that no delayed neutrons are produced in the system, the prompt kinetics equations for critical system and subcritical system with an external source are proposed. And then the equations are applied to calculating Λ with pulsed neutron technique using Monte Carlo. Only one fission neutron source is simulated with Monte Carlo in critical system while two neutron sources, including a fission source and an external source, are simulated for subcritical system. Calculations are performed on both critical benchmarks and subcritical system with an external source and the results are consistent with the reference values. (author)

  13. Detection of renal cell carcinoma using neutron time of flight spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Viana, Rodrigo S.; Yoriyaz, Helio, E-mail: rodrigossviana@gmail.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Lakshmanan, Manu N.; Agasthya, Greeshma A.; Kapadia, Anuj J. [Duke University Medical Center, Durham, NC, (United States). Ravin Advanced Imaging Labs, Radiology

    2013-07-01

    The diagnosis of renal cell carcinoma (RCC) is challenging because the symptoms accompanying it are not unique to the disease, and can therefore be misdiagnosed as other diseases. Due to this characteristic, detection of renal cancer is incidental most of time, occurring via abdominal radiographic examinations unrelated to the disease. Presently, biopsy, which is invasive and an unpleasant procedure for the patient, is the most commonly used technique to diagnose RCC. In this study, we demonstrate the application of a novel noninvasive technique for detecting and imaging RCC in vivo. The elemental composition of biological tissues including kidneys has been investigated using a new technique called Neutron Stimulated Emission Computed Tomography (NSECT). This technique is based on detecting the energy signature emitted by the stable isotopes of elements in the body, which are stimulated to emit gamma radiation via inelastic neutron scattering. Methods for improving detection sensitivity and reducing dose, such as time-of-flight neutron spectroscopy have been explored. MCNP5 simulations were used to model the NSECT scanning of the human kidney where the energy and time of arrival of gamma photons were recorded in an ideal detector placed around the human torso. A 5 MeV collimated neutron beam was used to irradiate the kidney containing an RCC lesion. The resulting spectra were resolved in 100 picosecond and 1 keV time and energy bins, respectively. The preliminary results demonstrate the ability to localize the lesion through neutron time of flight spectroscopy and generate a tomographic image at a low dose to the patient. (author)

  14. Estimation of optimum time interval for neutron- γ discrimination by simplified digital charge collection method

    International Nuclear Information System (INIS)

    The discrimination of mixed radiation field is of prime importance due to its application in neutron detection which leads to radiation safety, nuclear material detection etc. The liquid scintillators are one of the most important radiation detectors because the relative decay rate of neutron pulse is slower as compared to gamma radiation in these detectors. There are techniques like zero crossing and charge comparison which are very popular and implemented using analogue electronics. In the recent years due to availability of fast ADC and FPGA, digital methods for discrimination of mixed field radiations have been investigated. Some of the digital time domain techniques developed are pulse gradient analysis (PGA), simplified digital charge collection method (SDCC), digital zero crossing method. The performance of these methods depends on the appropriate selection of gate time for which the pulse is processed. In this paper, the SDCC method is investigated for a neutron-gamma mixed field. The main focus of the study is to get the knowledge of optimum gate time which is very important in neutron gamma discrimination analysis in a mixed radiation field. The comparison with charge collection (CC) method is also investigated

  15. Multi-purpose fast neutron spectrum analyzer with real-time signal processing

    Energy Technology Data Exchange (ETDEWEB)

    Sulyaev, Yu.S., E-mail: sulyaev@inp.nsk.su [Budker Institute of Nuclear Physics SB RAS, 630090 Novosibirsk (Russian Federation); Novosibirsk State University, 630090 Novosibirsk (Russian Federation); Puryga, E.A.; Khilchenko, A.D. [Budker Institute of Nuclear Physics SB RAS, 630090 Novosibirsk (Russian Federation); Novosibirsk State Technical University, 630092 Novosibirsk (Russian Federation); Kvashnin, A.N. [Budker Institute of Nuclear Physics SB RAS, 630090 Novosibirsk (Russian Federation); Polosatkin, S.V. [Budker Institute of Nuclear Physics SB RAS, 630090 Novosibirsk (Russian Federation); Novosibirsk State University, 630090 Novosibirsk (Russian Federation); Rovenskikh, A.F. [Budker Institute of Nuclear Physics SB RAS, 630090 Novosibirsk (Russian Federation); Burdakov, A.V.; Grishnyaev, E.V. [Budker Institute of Nuclear Physics SB RAS, 630090 Novosibirsk (Russian Federation); Novosibirsk State Technical University, 630092 Novosibirsk (Russian Federation)

    2013-08-21

    Diagnostics of hot ion component of plasma on the products of fusion reactions is widely used on thermonuclear facilities. In case of employment of neutron spectrometers, based on organics scintillators, there is advanced technique developed to eliminate neutron pulses from gamma background—digital pulse shape discrimination. For every DPSD application it is necessary to use the fast (2–5 ns) and precise (12 bit) transient ADC unit with large amount of onboard memory for storing every digitized scintillation pulses during shot time. At present time the duration of hot thermonuclear plasma burning in large tokamaks approximate to 1 min, and this requires very high onboard memory capacity (∼100 GB). This paper describes a neutron spectrum analyzer with real-time DPSD algorithm, implemented to ADC unit. This approach saves about two orders of onboard memory capacity, gives the possibility of instant use of outcome to feedback systems. This analyzer was tested and calibrated with help of {sup 60}Co and {sup 252}Cf radiation sources, and deuterium neutron generator.

  16. Music, videos and the risk for CERN

    CERN Multimedia

    IT Department

    2010-01-01

    Do you like listening to music while working? What about watching videos during leisure time? Sure this is fun. Having your colleagues participating in this is even more fun. However, this fun is usually not free. There are music and film companies who earn their living from music and videos. Thus, if you want to listen to music or watch films at CERN, make sure that you own the proper rights to do so (and you have the agreement of your supervisor to do this during working hours). Note that these rights are personal: You usually do not have the right to share this music or these videos with third parties without violating copyrights. Therefore, making copyrighted music and videos public, or sharing music and video files as well as other copyrighted material, is forbidden at CERN --- and also outside CERN. It violates the CERN Computing Rules (http://cern.ch/ComputingRules) and it contradicts CERN's Code of Coduct (https://cern.ch/hr-info/codeofconduct.asp) which expects each of us to behave ethically and be ...

  17. Neutron Scattering in Hydrogenous Moderators, Studied by Time Dependent Reaction Rate Method

    International Nuclear Information System (INIS)

    The moderation and absorption of a neutron burst in water, poisoned with the non-1/v absorbers cadmium and gadolinium, has been followed on the time scale by multigroup calculations, using scattering kernels for the proton gas and the Nelkin model. The time dependent reaction rate curves for each absorber display clear differences for the two models, and the separation between the curves does not depend much on the absorber concentration. An experimental method for the measurement of infinite medium reaction rate curves in a limited geometry has been investigated. This method makes the measurement of the time dependent reaction rate generally useful for thermalization studies in a small geometry of a liquid hydrogenous moderator, provided that the experiment is coupled to programs for the calculation of scattering kernels and time dependent neutron spectra. Good agreement has been found between the reaction rate curve, measured with cadmium in water, and a calculated curve, where the Haywood kernel has been used

  18. Cf-252 based neutron radiography using real-time image processing system

    International Nuclear Information System (INIS)

    For compact Cf-252 based neutron radiography, a real-time image processing system by particle counting technique has been developed. The electronic imaging system consists of a supersensitive imaging camera, a real-time corrector, a real-time binary converter, a real-time calculator for centroid, a display monitor and a computer. Three types of accumulated NR image; ordinary, binary and centroid images, can be observed during a measurement. Accumulated NR images were taken by the centroid mode, the binary mode and ordinary mode using of Cf-252 neutron source and those images were compared. The centroid mode presented the sharpest image and its statistical characteristics followed the Poisson distribution, while the ordinary mode showed the smoothest image as the averaging effect by particle bright spots with distributed brightness was most dominant. (author)

  19. CERN hosts training event on international management

    CERN Multimedia

    2007-01-01

    CERN held its first training event on international management at the Globe on 2 October, sharing its expertise with high-level Swiss managers as part of their year-long part-time executive training programme on advanced management. CERN is often talked about in terms of impressive statistics: the coldest place in the universe, the largest accelerator, the greatest volume of data. Whilst the science is undeniably remarkable, it is backed by a management infrastructure that has to be as cutting-edge as the research it supports. On 2 October, the Learning and Development section of HR organised an event for 60 delegates to come to CERN to learn about international management from those who have taken on the management challenges at the heart of this unique institution. It was the first time that CERN had prepared such an event. SKU, a non-profit organisation, approached our management training team to arrange the event as part of a wee...

  20. A digital data acquisition system for a time of flight neutron diffuse scattering instrument

    International Nuclear Information System (INIS)

    Full text. We describe the design of a digital data acquisition system built for acquiring and storing the information produced by a neutron diffuse scattering apparatus. This instrument is based on the analysis of pulsed subthermal neutron which are scattered by a solid or liquid sample, measured as function of the scattered neutron wavelength and momentum direction. The time of flight neutron intensities on 14 different angular detector positions and two fission chambers must be analyzed simultaneously for each neutron burst. A PC controlled data acquisition board system was built based on two parallel multiscannning units, each with its own add-one counting unit, and a common base time generator. The unit plugs onto the ISA bus through an interface card. Two separate counting units were designed, to avoid possible access competition between low counting rate counters at off-axis positions and the higher rate frontal 0 deg and beam monitoring counters. the first unit contains logic for 14 independent and simultaneous multi scaling inputs, with 128 time channels and dwell time per channel of 5, 10 or 20 microseconds. Sweep trigger is synchronized with an electric signal from a coil sensing the rotor. The second unit contains logic for four additional multi scalers using the same external synchronizing signal, similar in all others details to the previously described multi scalers. Basic control routines for the acquisitions were written in C and a program for spectrum display and user interface was written in C++ for a Windows 3.1 OS. A block diagram of the system is presented

  1. Neutron monitors and muon detectors for solar modulation studies: 2. $\\phi$ time series

    OpenAIRE

    Ghelfi, A.; Maurin, D.; Cheminet, A.; Derome, L.; G. Hubert; Melot, F.

    2016-01-01

    The level of solar modulation at different times (related to the solar activity) is a central question of solar and galactic cosmic-ray physics. In the first paper of this series, we have established a correspondence between the uncertainties on ground-based detectors count rates and the parameter $\\phi$ (modulation level in the force-field approximation) reconstructed from these count rates. In this second paper, we detail a procedure to obtain a reference $\\phi$ time series from neutron mon...

  2. Two-phase fluid flow measurements in small diameter channels using real-time neutron radiography

    International Nuclear Information System (INIS)

    A series of real-time, neutron radiography, experiments are ongoing at the Texas A and M Nuclear Science Center Reactor (NSCR). These tests determine the resolving capabilities for radiographic imaging of two phase water and air flow regimes through small diameter flow channels. Though both film and video radiographic imaging is available, the real-time video imaging was selected to capture the dynamic flow patterns with results that continue to improve. (author)

  3. Parareal in time 3D numerical solver for the LWR Benchmark neutron diffusion transient model

    CERN Document Server

    Baudron, Anne-Marie A -M; Maday, Yvon; Riahi, Mohamed Kamel; Salomon, Julien

    2014-01-01

    We present a parareal in time algorithm for the simulation of neutron diffusion transient model. The method is made efficient by means of a coarse solver defined with large time steps and steady control rods model. Using finite element for the space discretization, our implementation provides a good scalability of the algorithm. Numerical results show the efficiency of the parareal method on large light water reactor transient model corresponding to the Langenbuch-Maurer-Werner (LMW) benchmark [1].

  4. Possibilities for polarized pulsed neutron instrumentation based on the time-of-flight spin-resonance energy filter

    International Nuclear Information System (INIS)

    We present a new approach for dynamic energy filtering at spallation neutron sources, based on the original concept of the Drabkin spin-resonance flipper. The setup takes advantage of the neutron magnetic moment, and consists of a wavelength-selective magnetic resonator and a supermirror polarizer/analyzer system. We are proposing refinements (time dependence and revised magnetic field profiles) to the basic concepts of the setup, making it suitable for time-of-flight experiments at spallation neutron sources. We outline here possibilities for using this spin resonator as the core of new neutron instruments. (orig.)

  5. Determination of Neutron Spectra in Bulk Media by Time-Of-Flight

    International Nuclear Information System (INIS)

    The time-of-flight method has recently been applied to the measurement of fast neutron spectra in bulk media to study problems of computing neutron distributions in reactor and shielding geometries. The advent of the high intensity, short pulse electron linear accelerator makes possible the collection of data in reasonable time for high resolution deep penetration experiments. Several experiments have been completed on geometries designed to be calculable by specific computer codes. Of particular interest is the class of one-dimensional geometries consisting of a central neutron source surrounded by spherical shells of homogeneous media with the outer boundary either spherical or essentially at infinity. To evaluate the ability to calculate fast neutron spectra in high-A materials, leakage spectra from a few keV to a few MeV were measured for a 6-in diameter lead sphere with a central (γ-n) neutron source. Results are compared with multigroup transport theory using cross-sections obtained by normalizing statistical theory with cross-section data. Spectra were also obtained at the lead-graphite interface for the above sphere encased in a 5-in thick, spherical, graphite shell. As expected, comparison of theory with experiment indicates that slowing down by low-A media is much better understood than slowing down by high-A media. The deep penetration problem, e.g. neutron shielding calculations, imposes extreme demands on computational methods both on accuracy required for input cross-sections, and on computational detail required to describe large attenuations. To study this problem, spectra were measured from 0.5 to 14 MeV for a point source, essentially infinite medium of paraffin. Measurements were made at several angles and radii out to 45-cm penetration. Results are compared with multigroup transport theory. Measurements have also been performed on a two-dimensional experiment (cylindrical medium, point source on axis) on the spectrum of deep

  6. EFQPSK Versus CERN: A Comparative Study

    Science.gov (United States)

    Borah, Deva K.; Horan, Stephen

    2001-01-01

    This report presents a comparative study on Enhanced Feher's Quadrature Phase Shift Keying (EFQPSK) and Constrained Envelope Root Nyquist (CERN) techniques. These two techniques have been developed in recent times to provide high spectral and power efficiencies under nonlinear amplifier environment. The purpose of this study is to gain insights into these techniques and to help system planners and designers with an appropriate set of guidelines for using these techniques. The comparative study presented in this report relies on effective simulation models and procedures. Therefore, a significant part of this report is devoted to understanding the mathematical and simulation models of the techniques and their set-up procedures. In particular, mathematical models of EFQPSK and CERN, effects of the sampling rate in discrete time signal representation, and modeling of nonlinear amplifiers and predistorters have been considered in detail. The results of this study show that both EFQPSK and CERN signals provide spectrally efficient communications compared to filtered conventional linear modulation techniques when a nonlinear power amplifier is used. However, there are important differences. The spectral efficiency of CERN signals, with a small amount of input backoff, is significantly better than that of EFQPSK signals if the nonlinear amplifier is an ideal clipper. However, to achieve such spectral efficiencies with a practical nonlinear amplifier, CERN processing requires a predistorter which effectively translates the amplifier's characteristics close to those of an ideal clipper. Thus, the spectral performance of CERN signals strongly depends on the predistorter. EFQPSK signals, on the other hand, do not need such predistorters since their spectra are almost unaffected by the nonlinear amplifier, Ibis report discusses several receiver structures for EFQPSK signals. It is observed that optimal receiver structures can be realized for both coded and uncoded EFQPSK

  7. CERN: Digitally open, too

    CERN Multimedia

    Computer Security Team

    2013-01-01

    The Open Days are here!! From tomorrow onwards, we will be welcoming thousands of people to CERN. No barriers, no boundaries!   For decades, we have welcomed researchers and visitors from around the world to work at CERN, discuss physics research and attend our training sessions, lectures and conferences. This is how fundamental research should be conducted!!! But have you ever noticed how you are welcome at CERN in the digital world, too? Once you are affiliated and are registered with CERN, you receive a CERN computing account and e-mail address.  You can register your laptops, PCs and smartphones to use our (wireless) network, you can easily create your personal webpage, and profit from a vast disk space for file storage (AFS and DFS). CERN is indeed an Open Campus and not only during the Open Days. CERN is an Open Campus in the digital world. This digital Open Campus culture is exactly the reason why “computer security” has been dele...

  8. CERN in 2030

    CERN Multimedia

    Laëtitia Pedroso

    2011-01-01

    A competition will soon be launched to select the architect, urban planner or landscape designer to undertake the first phase of redevelopment of the parking area by the flagpoles, between Entrances A and B. This will be the first stage in a wider development project aimed at sprucing up the CERN site and enhancing its image. Work to create a pleasant and harmonious area at the CERN entrance will start in 2013 while preparatory work for other developments inside the CERN site has already begun…   CERN as it is today.  By 2030, CERN will be a greener place, much like a university campus. The arrival of the tramway on 30 April will be an opportunity to forge ahead with the urban plan aimed at rejuvenating the CERN site and redefining how it is organised. "Nearly sixty years after CERN's first buildings went up, this plan will help transform the site and give it a welcoming, friendly face, a bit like a university campus," explains Thierry Chanard, urban plannin...

  9. CERN honours its guides

    CERN Multimedia

    2004-01-01

    At the end of January, CERN's guides were rewarded for their devotion to the Laboratory. They have a passion for their work, know CERN inside-out and for 40 years have shown people of all ages and nationalities, from all walks of life, around the Laboratory. Who are they? Why, the CERN guides, of course. On 27 January, ten of CERN's 180 guides received special honours for their impressive number of guided tours in 2003. Presenting the awards in the Microcosm hall, CERN's Director-General Robert Aymar congratulated the winners on the key role they play with respect to the general public. "CERN would be nothing without you who show them its activities," he stressed. CERN's Director-General Robert Aymar congratulates Alberto Ribon for his tally of over 40 visits in the course of 2003.One of the prizes was the book «The Particle Odyssey». Here the book's co-author Christine Sutton dedicates it for Sijin Qian. Tzanko Spassoff (PH) and retired staff members Klaus Batzner and Antonio Francano wo...

  10. Measurement of the Slowing-Down and Thermalization Time of Neutrons in Water

    International Nuclear Information System (INIS)

    The experimental equipment for the study of the time behaviour of neutrons during slowing-down and thermalization in a moderator by the use of a pulsed van de Graaff accelerator as a neutron source is described. Information on the change with time of the neutron spectrum is obtained from its reaction with spectrum indicators, the reaction rate being observed by the detection of capture gamma rays. The time resolution may be chosen in the range 0.01 to 5 μs. Measurements have been made for water with cadmium, gadolinium and samarium as indicators dissolved in the medium. A slowing- down time to 0.2 eV of 2.7 ± 0.4 μs and a total thermalization time of 25 - 30 μs were obtained. From 9 μs after the injection, the results are well described by the assumption of the flux as a Maxwell distribution cooling down to the moderator temperature with a thermalization time constant of 4.1 ± 0.4 μs

  11. Time-resolved Fast Neutron Radiography of Air-water Two-phase Flows

    Science.gov (United States)

    Zboray, Robert; Dangendorf, Volker; Mor, Ilan; Tittelmeier, Kai; Bromberger, Benjamin; Prasser, Horst-Michael

    Neutron imaging, in general, is a useful technique for visualizing low-Z materials (such as water or plastics) obscured by high-Z materials. However, when significant amounts of both materials are present and full-bodied samples have to be examined, cold and thermal neutrons rapidly reach their applicability limit as the samples become opaque. In such cases one can benefit from the high penetrating power of fast neutrons. In this work we demonstrate the feasibility of time-resolved, fast neutron radiography of generic air-water two-phase flows in a 1.5 cm thick flow channel with Aluminum walls and rectangular cross section. The experiments have been carried out at the high-intensity, white-beam facility of the Physikalisch-Technische Bundesanstalt, Germany. Exposure times down to 3.33 ms have been achieved at reasonable image quality and acceptable motion artifacts. Different two-phase flow regimes such as bubbly slug and churn flows have been examined. Two-phase flow parameters like the volumetric gas fraction, bubble size and bubble velocities have been measured.

  12. Evaluation of dominant time-eigenvalues of neutron transport equation by Meyer's sub-space iterations

    International Nuclear Information System (INIS)

    Highlights: → Meyer's sub-space iteration method is used to evaluate dominant prompt time eigenvalues of neutron transport equation. → Mono-energetic 1-D benchmark problems are analysed. → The method is found to correctly compute complex eigenvalues also. - Abstract: The aim of this paper is to explore the use of Meyer's sub-space iteration (SSI) method for the evaluation of dominant prompt time-eigenvalues of the neutron transport equation. The integro-differential form of the transport equation is considered. The SSI method is known to be an efficient technique to find the dominant eigenvalues of a non-symmetric matrix. It has been earlier used for eigenvalue problems in neutron diffusion theory. However, it does not seem to be tried in the transport theory case. Here, the use of SSI has been tested in transport theory for some 1-D mono-energetic homogeneous and heterogeneous benchmark problems. The space variable is discretised by finite differencing while neutron directions are discretised by discrete ordinates (Sn-) method. The SSI method needs frequent multiplication of the relevant matrix operator with vectors. As known from earlier works in this area, this can be achieved in terms of external source calculations for which a 1-D programme was developed and used. With the availability of more versatile Sn-method codes, it may perhaps be possible to extend use of SSI to more realistic cases.

  13. Time-of-flight mass measurements for nuclear processes in neutron star crusts

    CERN Document Server

    Estrade, A; Schatz, H; Amthor, A M; Bazin, D; Beard, M; Becerril, A; Brown, E F; Cyburt, R; Elliot, T; Gade, A; Galaviz, D; George, S; Gupta, S S; Hix, W R; Lau, R; Lorusso, G; Moller, P; Pereira, J; Portillo, M; Rogers, A M; Shapira, D; Smith, E; Stolz, A; Wallace, M; Wiescher, M

    2011-01-01

    The location of electron capture heat sources in the crust of accreting neutron stars depends on the masses of extremely neutron-rich nuclei. We present first results from a new implementation of the time-of-flight technique to measure nuclear masses of rare isotopes at the National Superconducting Cyclotron Laboratory. The masses of 16 neutron-rich nuclei in the scandium -- nickel range were determined simultaneously, improving the accuracy compared to previous data in 12 cases. The masses of $^{61}${V}, $^{63}${Cr}, $^{66}${Mn}, and $^{74}${Ni} were measured for the first time with mass excesses of $-30.510(890)$ MeV, $-35.280(650)$ MeV, $-36.900(790)$ MeV, and $-49.210(990)$ MeV, respectively. With the measurement of the $^{66}$Mn mass, the locations of the two dominant electron capture heat sources in the outer crust of accreting neutron stars that exhibit superbursts are now experimentally constrained. We find that the location of the $^{66}$Fe$\\rightarrow^{66}$Mn electron capture transition occurs signi...

  14. Study of the $^{234}$U(n,f) fission fragment angular distribution at the CERN n_TOF facility

    CERN Document Server

    Cidoncha-Leal, E; Paradela, C; Tarrío, D; Leong, L S; Audouin, L; Tassan-Got, L; Altstadt, S; Andrzejewski, J; Barbagallo, M; Bécares, V; Becvár, F; Belloni, F; Berthoumieux, E; Billowes, J; Boccone, V; Bosnar, D; Brugger, M; Calviani, M; Calviño, F; Cano-Ott, D; Carrapiço, C; Cerutti, F; Chiaveri, E; Chin, M; Colonna, N; Cortés, G; Cortés-Giraldo, M A; Diakaki, M; Domingo-Pardo, C; Dressler, R; Dzysiuk, N; Eleftheriadis, C; Ferrari, A; Fraval, K; Ganesan, S; García, A R; Giubrone, G; Gómez-Hornillos, M B; Gonçalves, I F; González-Romero, E; Griesmayer, E; Guerrero, C; Gunsing, F; Gurusamy, P; Hernández-Prieto, A; Jenkins, D G; Jericha, E; Kadi, Y; Käppeler, F; Karadimos, D; Kivel, N; Koehler, P; Kokkoris, M; Krticka, M; Kroll, J; Lampoudis, C; Langer, C; Lederer, C; Leeb, H; Losito, R; Mallick, A; Manousos, A; Marganiec, J; Martínez, T; Massimi, C; Mastinu, P F; Mastromarco, M; Meaze, M; Mendoza, E; Mengoni, A; Milazzo, P M; Mingrone, F; Mirea, M; Mondalaers, W; Pavlik, A; Perkowski, J; Plompen, A; Praena, J; Quesada, J M; Rauscher, T; Reifarth, R; Riego, A; Robles, M S; Roman, F; Rubbia, C; Sabaté-Gilarte, M; Sarmento, R; Saxena, A; Schillebeeckx, P; Schmidt, S; Schumann, D; Tagliente, G; Tain, J L; Tsinganis, A; Valenta, S; Vannini, G; Variale, V; Vaz, P; Ventura, A; Versaci, R; Vermeulen, M J; Vlachoudis, V; Vlastou, R; Wallner, A; Ware, T; Weigand, M; Weiß, C; Wright, T; Zugec, P

    2014-01-01

    The angular distribution of the f ssion fragments (FFAD) produced in neutron- induced reactions of actinides have been measured with a f ssion detection setup based on parallel-plate avalanche counters (PPACs) at the Neutron Time- Of-Flight (n_TOF) facility at CERN. The main features of the setup and pre- liminary results are reported here forthe 234 U(n,f)reaction measurement show- ing a high concordance with previous data, while providing new results up to 100 MeV.

  15. Forthcoming (n, {gamma}) measurements on the Fe and Ni isotopes at CERN n{sub T}OF

    Energy Technology Data Exchange (ETDEWEB)

    Domingo-Pardo, C [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Andriamonje, S; Berthoumieux, E [CEA/Saclay - DSM, Gif-sur-Yvette (France); Andrzejewski, J [University of Lodz, Lodz (Poland); Audouin, L; Berthier, B [Centre National de la Recherche Scientifique/IN2P3 - IPN, Orsay (France); Avrigeanu, V [National Institute of Physics and Nuclear Engineering - IFIN, Bucharest (Romania); Becvar, F [Charles University, Prague (Czech Republic); Belloni, F [Istituto Nazionale di Fisica Nucleare, Trieste (Italy); Brugger, M; Cerutti, F; Chiaveri, F [CERN, Geneva (Switzerland); Calviani, M [Istituto Nazionale di Fisica Nucleare(INFN), Laboratori Nazionali di Legnaro (Italy); Calvino, F; Cortes, G [Universitat Politecnica de Catalunya, Barcelona (Spain); Cano-Ott, D [Centro de Investigaciones Energeticas Medioambientales y Technologicas, Madrid (Spain); Colonna, N [Istituto Nazionale di Fisica Nucleare, Bari (Italy); Dillmann, I [Physik-Department E12, Technische Universitaet Muenchen, Beschleunigerlaboratorium, Garching (Germany); Duran, I [Universidade de Santiago de Compostela (Spain); Carrapico, C, E-mail: c.domingopardo@gsi.d

    2010-01-01

    An overview of the past, present and future research activities at the CERN neutron time of flight facility n{sub T}OF is given, with special focus on the astrophysical aspects. During the first campaign (Phase I), neutron capture cross sections of relevance for several aspects of the s-process nucleosynthesis have been measured. A second campaign has recently started (Phase II), aiming at the study of the weak s-process component via accurate (n,{gamma}) measurements of the Fe and Ni isotopes. Some changes in the facility will allow us to perform these measurements with improved experimental conditions.

  16. La Hollande au CERN

    CERN Document Server

    CERN Press Office. Geneva

    1995-01-01

    On 17 October the third industrial exhibition, "Holland at CERN" was officially opened by Dr R.J. van Duinen, President of the Dutch Organisation for Scientific Research (NWO). In his opening speech he encouraged scientific organisations such as CERN to take full advantage of industry's ability to design and invent new processes and equipment stressing that the purpose of the "Holland at CERN" exhibition was not simply to sell equipment, but to establish an efficient cross-fertilisation between fundamental science and industry.

  17. Neutron radiography, a powerful method to determine time-dependent moisture distributions in concrete

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Peng [Center for Durability and Sustainability Studies of Shandong Province, Qingdao Technological University, 11 Fushun Road, Qingdao 266033 (China); Wittmann, Folker H., E-mail: wittmann@aedificat.de [Center for Durability and Sustainability Studies of Shandong Province, Qingdao Technological University, 11 Fushun Road, Qingdao 266033 (China); Aedificat Institute Freiburg, Schlierbergstr. 80, D-79100 Freiburg (Germany); Zhao Tiejun [Center for Durability and Sustainability Studies of Shandong Province, Qingdao Technological University, 11 Fushun Road, Qingdao 266033 (China); Lehmann, Eberhard H.; Vontobel, Peter [Neutron Imaging and Activation Group, Paul Scherrer Institute, CH-5232 Villigen PSI (Switzerland)

    2011-12-15

    Highlights: Black-Right-Pointing-Pointer For the first time water movement in cement-based materials could be quantified in a non-destructive way. Black-Right-Pointing-Pointer neutron radiography has a sensitivity and a spatial resolution unknown so far. Black-Right-Pointing-Pointer Results are essential for prediction of service life. Black-Right-Pointing-Pointer Results will contribute to more durable and more ecological construction. - Abstract: Service life of reinforced concrete structures is often limited by penetration of water and compounds dissolved in water into concrete. Concrete can be damaged in this way and corrosion of steel reinforcement can be initiated. There is an urgent need to study water penetration into concrete in order to better understand deterioration mechanisms and to find appropriate ways to improve durability. Neutron radiography provides us with an advanced non-destructive technique with high spatial resolution and extraordinary sensitivity. In this contribution, neutron radiography was successfully applied to study the process of water absorption of two types of concrete with different water-cement ratios, namely 0.4 and 0.6. The influence cracks and of water repellent treatment on water absorption has been studied on mortar specimens. It is possible to visualize migration of water into concrete and other cement-based composites and to quantify the time-dependent moisture distributions as function of time with high spatial resolution by means of neutron radiography. Water penetration depth obtained from neutron radiography is in good agreement with corresponding values obtained from capillary suction tests. Surface impregnation of concrete with silane prevents capillary uptake of water. Even fine cracks are immediately filled with water as soon as the surface gets in contact. Results provide us with a solid basis for a better understanding of deteriorating processes in concrete and other cement-based materials.

  18. Neutron radiography, a powerful method to determine time-dependent moisture distributions in concrete

    International Nuclear Information System (INIS)

    Highlights: ► For the first time water movement in cement-based materials could be quantified in a non-destructive way. ► neutron radiography has a sensitivity and a spatial resolution unknown so far. ► Results are essential for prediction of service life. ► Results will contribute to more durable and more ecological construction. - Abstract: Service life of reinforced concrete structures is often limited by penetration of water and compounds dissolved in water into concrete. Concrete can be damaged in this way and corrosion of steel reinforcement can be initiated. There is an urgent need to study water penetration into concrete in order to better understand deterioration mechanisms and to find appropriate ways to improve durability. Neutron radiography provides us with an advanced non-destructive technique with high spatial resolution and extraordinary sensitivity. In this contribution, neutron radiography was successfully applied to study the process of water absorption of two types of concrete with different water–cement ratios, namely 0.4 and 0.6. The influence cracks and of water repellent treatment on water absorption has been studied on mortar specimens. It is possible to visualize migration of water into concrete and other cement-based composites and to quantify the time-dependent moisture distributions as function of time with high spatial resolution by means of neutron radiography. Water penetration depth obtained from neutron radiography is in good agreement with corresponding values obtained from capillary suction tests. Surface impregnation of concrete with silane prevents capillary uptake of water. Even fine cracks are immediately filled with water as soon as the surface gets in contact. Results provide us with a solid basis for a better understanding of deteriorating processes in concrete and other cement-based materials.

  19. Stochastic analog reactor period - time achievement a given level of number of neutrons

    International Nuclear Information System (INIS)

    In theory and in practice the operation of nuclear reactors to control the safety of the reactor is widely used the deterministic value of period of the reactor. It is proposed along with the period of the reactor using a stochastic analogue of this magnitude - a random value of time to achieve a given level of a random process for the number of neutrons in the reactor. Thr paper discusses various models for the distribution function of the lifetime of neutrons in the reactor, the knowledge which is important in the study of time to achieve the level and impact of the maximum possible time to achieve the level of the characteristics of the random variable

  20. Stochastic analog reactor period - time achievement a given level of number of neutrons

    International Nuclear Information System (INIS)

    In theory and in practice the operation of nuclear reactors to control the safety of the reactor is widely used the deterministic value of period of the reactor. It is proposed along with the period of the reactor using a stochastic analogue of this magnitude - a random value of time to achieve a given level of a random process for the number of neutrons in the reactor. The paper discusses various models for the distribution function of the lifetime of neutrons in the reactor, the knowledge which is important in the study of time to achieve the level and impact of the maximum possible time to achieve the level of the characteristics of the random variable

  1. The MRSt for time-resolved measurements of the neutron spectrum at the NIF

    Science.gov (United States)

    Frenje, J.; Gatu Johnson, M.; Li, C.; Seguin, F.; Petrasso, R.; Hilsabeck, T.; Kilkenny, J.; Bionta, R.; Cerjan, C.

    2015-11-01

    Information about the time evolution of inertial-confinement-fusion fuel assembly and hot-spot formation can be obtained with the next-generation Magnetic Recoil Spectrometer (MRS) for time-resolved measurements of the neutron spectrum. This spectrometer, called MRSt, represents a paradigm shift in our thinking about neutron spectrometers for ICF applications, as it will provide simultaneously information about the burn history and ρR -Ti trajectory during burn. As the peak burn generally occurs before and after peak compression in failed and ignited implosions, respectively, an MRSt measurement of the relative timing of these events will be critical for assessing implosion dynamics. This work was supported in part by the U.S. DOE, LLNL and LLE.

  2. Statistics of quantum beats in the time dependence of the neutron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Prokopets, G.A.; Prokopets, A.G. [National University of Kyiv-Mohyla Academy, Physics and Mathematics Department, Kyiv (Ukraine)

    2011-12-15

    The numerical calculations of the delay time distributions for the neutron scattering have been carried out. The scattering of the short wave packet of neutrons with the broad energy interval 500-800 keV by {sup 58}Ni nuclei has been studied. The decay curves and average times of the compound scattering were found as for the forward scattering as for the specific spin-parity states. The time oscillations of the decay curves were identified as quantum beats that were caused by the interference of the excited resonance set. The statistical analysis of the frequency spectra of the decay curves oscillations has been carried out. The behavior of the examined statistical observables turns out to be close to the Poisson law. (orig.)

  3. Statistics of quantum beats in the time dependence of the neutron scattering

    International Nuclear Information System (INIS)

    The numerical calculations of the delay time distributions for the neutron scattering have been carried out. The scattering of the short wave packet of neutrons with the broad energy interval 500-800 keV by 58Ni nuclei has been studied. The decay curves and average times of the compound scattering were found as for the forward scattering as for the specific spin-parity states. The time oscillations of the decay curves were identified as quantum beats that were caused by the interference of the excited resonance set. The statistical analysis of the frequency spectra of the decay curves oscillations has been carried out. The behavior of the examined statistical observables turns out to be close to the Poisson law. (orig.)

  4. Neutron capture measurements on 62Ni, 63Ni and 197Au and their relevance for stellar nucleosynthesis

    CERN Document Server

    Lederer, Claudia

    Neutron capture reactions in stars are responsible for forming about 99% of the elemental abundances heavier than Fe. Two processes contribute about equally to the overall abundance pattern: the slow neutron capture process (s process) where neutron densities are small and therefore radioactive decay is generally faster than subsequent neutron capture on radionuclides, and the rapid neutron capture process (r process) which takes place in environments of high neutron densities, driving the reaction path towards the neutron rich side. The key nuclear physics input for s process studies are stellar neutron capture cross sections, called MACS (Maxwellian-averaged cross section). In the course of this work, dierent reactions relevant to s process nucleosynthesis have been studied. To improve and check existing information, neutron capture cross sections of most stable Fe and Ni isotopes were measured via the time-of-flight technique at the n TOF facility at CERN. This campaign was triggered by a work of Sneden et...

  5. Phonon-Magnon coupling in CoF$_2$ investigated by time-of-flight neutron spectroscopy

    OpenAIRE

    Chatterji, Tapan; Zbiri, Mohamed; Rols, Stephane

    2013-01-01

    We report the results of inelastic neutron scattering investigation on the model antiferromagnet CoF$_2$ by time-of-flight neutron spectroscopy. We measured the details of the scattering function $S(Q,\\omega)$ as a function of temperature with two different incident neutron wavelengths. The temperature and Q dependence of the measured scattering function suggests the presence of magnon-phonon coupling in almost all branches. The present results are in agreement with the strong magnetoelastic ...

  6. Colloquium: Measuring the neutron star equation of state using x-ray timing

    Science.gov (United States)

    Watts, Anna L.; Andersson, Nils; Chakrabarty, Deepto; Feroci, Marco; Hebeler, Kai; Israel, Gianluca; Lamb, Frederick K.; Miller, M. Coleman; Morsink, Sharon; Özel, Feryal; Patruno, Alessandro; Poutanen, Juri; Psaltis, Dimitrios; Schwenk, Achim; Steiner, Andrew W.; Stella, Luigi; Tolos, Laura; van der Klis, Michiel

    2016-04-01

    One of the primary science goals of the next generation of hard x-ray timing instruments is to determine the equation of state of matter at supranuclear densities inside neutron stars by measuring the radius of neutron stars with different masses to accuracies of a few percent. Three main techniques can be used to achieve this goal. The first involves waveform modeling. The flux observed from a hotspot on the neutron star surface offset from the rotational pole will be modulated by the star's rotation, and this periodic modulation at the spin frequency is called a pulsation. As the photons propagate through the curved spacetime of the star, information about mass and radius is encoded into the shape of the waveform (pulse profile) via special and general-relativistic effects. Using pulsations from known sources (which have hotspots that develop either during thermonuclear bursts or due to channeled accretion) it is possible to obtain tight constraints on mass and radius. The second technique involves characterizing the spin distribution of accreting neutron stars. A large collecting area enables highly sensitive searches for weak or intermittent pulsations (which yield spin) from the many accreting neutron stars whose spin rates are not yet known. The most rapidly rotating stars provide a clean constraint, since the limiting spin rate where the equatorial surface velocity is comparable to the local orbital velocity, at which mass shedding occurs, is a function of mass and radius. However, the overall spin distribution also provides a guide to the torque mechanisms in operation and the moment of inertia, both of which can depend sensitively on dense matter physics. The third technique is to search for quasiperiodic oscillations in x-ray flux associated with global seismic vibrations of magnetars (the most highly magnetized neutron stars), triggered by magnetic explosions. The vibrational frequencies depend on stellar parameters including the dense matter equation of

  7. Princess of Thailand returns to CERN

    CERN Multimedia

    Stefania Pandolfi

    2015-01-01

    On Tuesday, 17 November 2015, HRH Princess Maha Chakri Sirindhorn of Thailand visited CERN. Princess Sirindhorn was visiting the Laboratory for the fifth time, following her last visit in 2010.   Princess Maha Chakri Sirindhorn of Thailand (center) witnesses the signing of the collaboration agreement between CERN and SLRI, represented by Rolf Heuer (right) and Professor Sarawut Sujitjorn (left) respectively. The Princess was accompanied by a delegation that included the Director of the Synchrotron Light Research Institute (SLRI) in Thailand, Professor Sarawut Sujitjorn, and a large group of Thailand’s Diplomatic Representatives in Switzerland. Upon her arrival, Princess Sirindhorn was welcomed by CERN Director-General Rolf Heuer and the Director-General Designate, Fabiola Gianotti. At CERN, the Princess was given a brief update on the Laboratory’s activities since her last visit, in April 2010. Later on, she witnessed the signature of the f...

  8. The distance from CERN to LNGS

    CERN Document Server

    Jones, M; Crespi, M; Colosimo, G; Mazzoni, A; Durand, S

    2012-01-01

    The calculation of the distance from CERN to Gran Sasso involves the combination of three independent sets of measurements: the calculation of the distance between pillars included in the geodetic reference network at CERN and the Lab Nationale Gran Sasso (LNGS); and the transfer on each site of coordinates, from the geodetic surface network, underground into the tunnel or experiment hall installations. The transfer of coordinates, from the surface, underground at the two sites was not done as part of the CNGS Project. Initial survey concerns for the project were directed towards the orientation of the beamline from CERN to LNGS to within ~100 m. Gyro-theodolite measurements underground were planned at CERN so a transfer would effectively only translate the target point. Given the precision estimated for previous transfers, it was decided not to undertake expensive and time-consuming measurements campaigns for a negligible gain in accuracy. Therefore only GPS measurements at the two sites were carried out. Th...

  9. Star spotting at CERN

    CERN Multimedia

    2008-01-01

    This June, two American celebrities (and physics enthusiasts!) came to CERN. Brian Cox gave Mike Einziger (right), lead guitarist with the rock band Incubus, the star treatment in the ATLAS cavern. Jesse Dylan embraces the spirit of ATLAS! Mike Einziger, lead guitarist with the rock band Incubus, visited CERN on Friday 13 June between concerts in Finland and England. Einziger, a lifelong science enthusiast descended into the ATLAS and CMS caverns and visited the SM18 test magnet facility during his brief tour of CERN. Einziger learned about the LHC through watching online lectures from University of Manchester and ATLAS physicist Brian Cox, and was thrilled to have the chance to see the detectors in person. The musician has created an orchestral piece, inspired in part by the work being done at CERN for the LHC, which will have its debut in Los Angeles on 23 August. Just over a week earlier, Jesse Dylan, Hollywood film director a...

  10. Ex / Noise / CERN / Deerhoof

    CERN Multimedia

    CERN, SM18,

    2015-01-01

    Indie rockers Deerhoof battled with the noise of CERN’s magnet test facilities on 30 August 2015. The band visited CERN at the invitation of ATLAS physicist James Beacham, whose pilot project Ex/Noise/CERN collides experimental music artists with experimental particle physics. Credits: -Producer- CERN Video Productions James Beacham François Briard -Director- Noemi Caraban -Camera- Yann Krajewski Piotr Traczyk Noemi Caraban -Crane operator- Antonio Henrique Jorge-Costa -Live recording at CERN- Mixing at Rec studio/Geneva By Serge Morattel -Infography- Daniel Dominguez Noemi Caraban -Deerhoof- John Dieterich Satomi Matsuzaki Ed Rodriguez Greg Saunier w/Deron Pulley SPECIAL THANKS TO: Michal Strychalski Marta Bajko Maryline Charrondiere Luca Bottura Christian Giloux Rodrigue Faes Mariane Catallon Georgina Hobgen Hailey Reissman Marine Bass

  11. Britain exhibition at CERN

    CERN Multimedia

    Bertin; CERN PhotoLab

    1969-01-01

    The United Kingdom inaugurated the Industrial Exhibitions in 1968, and it wasn't till 1971 that other countries staged exhibitions at CERN. This photo was taken in 1969, at the second British exhibition, where 16 companies were present.

  12. Indian President visits CERN

    CERN Multimedia

    Katarina Anthony

    2011-01-01

    On 1 October, her Excellency Mrs Pratibha Devisingh Patil, President of India, picked CERN as the first stop on her official state visit to Switzerland. Accompanied by a host of Indian journalists, a security team, and a group of presidential delegates, the president left quite an impression when she visited CERN’s Point 2!   Upon arrival, Pratibha Patil was greeted by CERN Director General Rolf Heuer, as well as senior Indian scientists working at CERN, and various department directors. After a quick overview of the Organization, Rolf Heuer and the President addressed India’s future collaboration with CERN. India is currently an Observer State of the Organization, and is considering becoming an Associate Member State. A short stop in LHC operations gave Steve Myers and the Accelerator team the opportunity to take the President on a tour through the LHC tunnel. From there, ALICE’s Tapan Nayak and Spokesperson Paolo Giubellino took Pratibha Patil to the experiment&am...

  13. Open Hardware at CERN

    CERN Multimedia

    CERN Knowledge Transfer Group

    2015-01-01

    CERN is actively making its knowledge and technology available for the benefit of society and does so through a variety of different mechanisms. Open hardware has in recent years established itself as a very effective way for CERN to make electronics designs and in particular printed circuit board layouts, accessible to anyone, while also facilitating collaboration and design re-use. It is creating an impact on many levels, from companies producing and selling products based on hardware designed at CERN, to new projects being released under the CERN Open Hardware Licence. Today the open hardware community includes large research institutes, universities, individual enthusiasts and companies. Many of the companies are actively involved in the entire process from design to production, delivering services and consultancy and even making their own products available under open licences.

  14. CERN stationery rejuvenated

    CERN Multimedia

    Anaïs Schaeffer

    2013-01-01

    With the introduction of CERN’s new graphic charter, our complete range of official communications stationery has been redesigned. Discover the newly harmonised and standardised range of CERN stationery.   As the Director-General announced in Bulletin 41-42/2012, a new graphic charter is now in force at CERN. The graphics team has taken this opportunity to redesign all the official CERN stationery, such as business cards, correspondence cards, letterheads, envelopes and file holders, all of which will now boast the same, unified format. In keeping with CERN’s new graphic charter, even the business cards have had a makeover: of a better quality than their predecessors, they now elegantly display the CERN colours (namely the familiar Pantone 286 blue). These new cards, which all follow a standardised format, help to project a standardised corporate image of the Organization. Order them online now! As the Director-General highlighted, “it's increasingly imp...

  15. CERN meets Facebook

    CERN Multimedia

    2012-01-01

    Social networking sites like LinkedIn, MySpace, Google+ and Facebook are on the rise. In particular, the life of youngsters revolves more and more around these sites as they facilitate communication, networking and the exchange of niceties. Who does not today already have an account registered with one of them? A Facebook profile can contain photos, listings of hobbies, job information, preferences…   The on-going effort to externalise some of CERN's computing resources continues, and in order to promote a unified interface for personal information, CERN has decided to establish a partnership with Facebook starting on 1stApril. "CERN is a public and trustworthy international organisation, and as such, our staff and users have nothing to hide from the general public," said Alexi Spiner (IT), project leader responsible for this migration: * The computer profiles of all CERN users will be integrated into the Facebook portal; * In addition, we will also ...

  16. Rejuvenating CERN's Accelerators

    CERN Multimedia

    2004-01-01

    In the coming years and especially in 2005, CERN's accelerators are going to receive an extensive renovation programme to ensure they will perform reliably and effectively when the LHC comes into service.

  17. CERN Science and Technology

    OpenAIRE

    Di Meglio, Alberto

    2015-01-01

    A high-level overview of the relationship between science and technology at CERN and the impact of technology on research with a focus on ICT technologies. Presented as a 12-minute "power-talk" at CIOCity 2015, Brussels

  18. PACMAN at CERN

    CERN Multimedia

    2015-01-01

    PACMAN Particle Accelerator Components Metrology and Alignment to the Nanometre scale. PACMAN is an Innovative Doctoral Program Network, offering training to 10 Early Stage Researchers hosted by CERN thanks to The European Commission FP7 Marie Curie Actions.

  19. YOUR LIFE@CERN

    CERN Multimedia

    Guinot, Genevieve

    2016-01-01

    Balancing work and home life, getting support for your family and thriving in an inclusive and respectful workplace: find out more about the support structures in place to enhance your working life@CERN!

  20. CERN at ESOF 2016

    CERN Multimedia

    James Gillies

    2016-01-01

    CERN had a major presence at the ESOF2016 conference this week, largely in collaboration with our EIROforum partners. A keynote session featuring the CERN Director-General, Fabiola Gianotti, EMBL Director-General, Iain Mattaj, and ESO Director for Science, Rob Ivison, and chaired by BBC science correspondent Pallab Ghosh debated the value of European collaboration in science.   The focal point of EIROforum’s presence was a stand highlighting the societal benefit of EIROforum science. (Image: Matt Wilkinson Photography/ ESOF 2016) A double session covered the science of the EIROs, with ATLAS physicist Claire Lee representing CERN, and there was a session exploring the ways that the EIROforum organisations create business value locally, with the leader of the Knowledge Transfer group, Giovanni Anelli, representing CERN. The focal point of EIROforum’s presence was a stand highlighting the societal benefit of EIROforum science. Side events linked to the stand discussed subjects su...

  1. La nascita del CERN

    CERN Multimedia

    Fidecaro, Giuseppe

    2004-01-01

    CERN was born on 30th September 1954, after the ratification of the Convention by the Member States. After the war, there was a need for international collaboration to rebuild the half-destroyed Europe (2 pages)

  2. Iran approaches CERN

    CERN Multimedia

    2002-01-01

    Members of Parliament from the Islamic Republic of Iran visit SM18. From left to right : Ali Mojtahed-Shabestari, Deputy Ambassador of the Islamic Republic of Iran in Geneva, Diether Blechschmidt, from CERN, Abdol-Rahim Baharvand and Hossain Amiri, from the Iranian Parliament, Norbert Siegel, from CERN, Hossain Afarideh, Rasool Seddighi and Ahmad Shirzad from the Iranian Parliament. Five members of the Parliament of the Islamic Republic of Iran visited CERN for three days at the beginning of May. All of them have PhD's in Physics, as well as holding their job in politics. They are involved in legislation for science, research and education funding in Iran. Apart from their interest in CERN in general, they were especially attracted to the CMS detector, since an Iranian contribution to the LHC is now starting through a collaboration with the Institute for Studies in Theoretical Physics and Mathematics in Tehran.

  3. CERN recognises LHC suppliers

    CERN Multimedia

    2002-01-01

    CERN has just presented the first awards recognising LHC suppliers. The Russian institute BINP, the Belgian firm Cockerill-Sambre and the US company Wah-Chang are the recipients of the first 'Golden Hadrons'.

  4. CERN scientists predict supernova

    CERN Multimedia

    2003-01-01

    "A team of theoretical physicists working at CERN and the Technion Institute of Technology in Israel has developed a theory to account for the mysterious gamma ray bursts that come from the depths of the Universe" (1/2 page).

  5. CERN confirms LHC schedule

    CERN Multimedia

    2003-01-01

    The CERN Council held its 125th session on 20 June. Highlights of the meeting included confirmation that the LHC is on schedule for a 2007 start-up, and the announcement of a new organizational structure in 2004.

  6. Safety at CERN

    CERN Multimedia

    2009-01-01

    Safety is an integral part of our working lives, and should be in our minds whatever job we do at CERN. Ultimately, safety is the responsibility of the Director General – your safety is my concern. That’s why I have this week appointed a new Safety Policy Committee (SAPOCO) that reflects the new Organizational structure of CERN. CERN’s Staff Rules and Regulations clearly lay out in chapter 3 the scope of safety at CERN as well as my responsibilities and yours in safety matters. At CERN, safety is considered in the broadest sense, encompassing occupational Health and Safety, environmental protection, and the safety of equipment and installations. It is my responsibility to put appropriate measures in place to ensure that these conditions are met. And it is the responsibility of us all to ensure that we are fully conversant with safety provisions applicable in our areas of work and that we comply with them. The appointment of a n...

  7. Fusion Revisits CERN

    CERN Multimedia

    2001-01-01

    It's going to be a hot summer at CERN. At least in the Main Building, where from 13 July to 20 August an exhibition is being hosted on nuclear fusion, the energy of the Stars. Nuclear fusion is the engine driving the stars but also a potential source of energy for mankind. The exhibition shows the different nuclear fusion techniques and research carried out on the subject in Europe. Inaugurated at CERN in 1993, following collaboration between Lausanne's CRPP-EPFL and CERN, with input from Alessandro Pascolini of Italy's INFN, this exhibition has travelled round Europe before being revamped and returning to CERN. 'Fusion, Energy of the Stars', from 13 July onwards, Main Building

  8. Open Compute Project at CERN

    CERN Document Server

    CERN. Geneva

    2014-01-01

    The Open Compute Project, OCP ( http://www.opencompute.org/), was launched by Facebook in 2011 with the objective of building efficient computing infrastructures at lowest possible cost. The technologies are released as open hardware design, with the goal to develop servers and data centers following the model traditionally associated with open source software projects. We have been following the OCP project for some time and decided to buy two OCP twin servers in 2013 to get some hands-on experience. The servers have been tested and compared with our standard hardware regularly acquired through large tenders. In this presentation we will give some relevant results from this testing and also discuss some of the more important differences that can matter for a larger deployment at CERN. Finally it will outline the details for a possible project for a larger deployment of OCP hardware for production use at CERN.

  9. TIMOC-72, 3-D Time-Dependent Homogeneous or Inhomogeneous Neutron Transport by Monte-Carlo

    International Nuclear Information System (INIS)

    1 - Nature of physical problem solved: TIMOC solves the energy and time dependent (or stationary) homogeneous or inhomogeneous neutron transport equation in three-dimensional geometries. The program can treat all commonly used scattering kernels, such as absorption, fission, isotropic and anisotropic elastic scattering, level excitation, the evaporation model, and the energy transfer matrix model, which includes (n,2n) reactions. The exchangeable geometry routines consist at present of (a) periodical multilayer slab, spherical and cylindrical lattices, (b) an elaborate three-dimensional cylindrical geometry which allows all kinds of subdivisions, (c) the very flexible O5R geometry routine which is able to describe any body combinations with surfaces of second order. The program samples the stationary or time-energy-region dependent fluxes as well as the transmission ratios between geometrical regions and the following integral quantities or eigenvalues, the leakage rate, the slowing down density, the production to source ratio, the multiplication factor based on flux and collision estimator, the mean production time, the mean destruction time, time distribution of production and destruction, the fission rates, the energy dependent absorption rates, the energy deposition due to elastic scattering for the different geometrical regions. 2 - Method of solution: TIMOC is a Monte Carlo program and uses several, partially optional variance reducing techniques, such as the method of expected values (weight factor), Russian roulette, the method of fractional generated neutrons, double sampling, semi-systematic sampling and the method of expected leakage probability. Within the neutron lifetime a discrete energy value is given after each collision process. The nuclear data input is however done by group averaged cross sections. The program can generate the neutron fluxes either resulting from an external source or in the form of fundamental mode distributions by a special

  10. An artistic look at CERN

    CERN Multimedia

    2009-01-01

    The Japanese artist Mariko Mori visited CERN on 25 May. She met several scientists and found the visit very inspiring. CERN is becoming increasingly popular among artists of all kinds, from filmmakers to photographers, illustrators etc. Mariko Mori is not new to science-inspired artistic works; in 2006 she made Tom Na H-iu, a 3.2 m high glass sculpture illuminated by an internal LED connected in real time to the Super-Kamiokande neutrino detector in Japan. "When I worked with Super-Kamiokande I already had Tom Na H-iu in my mind; this time I am visiting CERN for my personal research", says Mori. "The LHC is a fantastic instrument whose challenge is to find the reality that we don’t know yet. In a way, art is also about creating new reality, although using a completely different approach. For me it is very important to gather information on what the whole scientific world is searching and reaching for: the truth of our existence, the...

  11. Detection of hidden explosives by using tagged neutron beams with sub-nanosecond time resolution

    International Nuclear Information System (INIS)

    Non-destructive inspection of luggage has been simulated in laboratory conditions by using a 14 MeV tagged neutron beam and BaF2 scintillation detectors (Tagged Neutron Inspection System, TNIS). The tagged neutron beam is produced by detecting the associated alpha particle emitted in the D+T reaction by means of a YAP:Ce scintillator. The TNIS intrinsic time resolution has been measured to be δt=0.9 ns [FWHM], which allows inspection of a minimum voxel of 5 cm depth along the neutron flight path. This characteristic is demonstrated by identifying graphite and water samples hidden inside a hard plastic suitcase filled with background material. Finally, explosive devices such as small anti-personnel or anti-tank landmines have been inspected when placed inside the suitcase. In the case of relatively large explosive objects such as an anti-tank landmine, the system is capable of testing directly the TNT charge inside the device, separating this material from the external plastic case. Further developments of the TNIS concept are discussed

  12. AMOR – the time-of-flight neutron reflectometer at SINQ/PSI

    Indian Academy of Sciences (India)

    Mukul Gupta; T Gutberlet; J Stahn; P Keller; D Clemens

    2004-07-01

    The apparatus for multioptional reflectometry (AMOR) at SINQ/PSI is a versatile reflectometer operational in the time-of-flight (TOF) mode (in a wavelength range of 0.15 nm > > 1.3 nm) as well as in the monochromatic ( - 2) mode with both polarized and unpolarized neutrons. AMOR is designed to perform reflectometry measurements in horizontal sample-plane geometry which allows studying both solid–liquid and liquid–liquid interfaces. A pulsed cold neutron beam from the end position of the neutron guide is produced by a dual-chopper system (side-by-side) having two windows at 180° and rotatable with a maximum frequency of 200 Hz. In the TOF mode, the chopper frequency, width of the gating window and the chopper–detector distance can be selected independently providing a wide range of -resolution ( / = 1–10%). Remanent FeCoV/Ti : N supermirrors are used as polarizer/analyzer with a polarization efficiency of ∼ 97%. For the monochromatic wavelength mode, a Ni/Ti multilayer is used as a monochromator, giving ∼ 50% reflectivity at a wavelength of 0.47 nm. In the present work, a detailed description of the instrument and setting-up of the polarization option is described. Results from some of the recent studies with polarized neutrons and measurements on liquid surfaces are presented.

  13. Detection of hidden explosives by using tagged neutron beams with sub-nanosecond time resolution

    Energy Technology Data Exchange (ETDEWEB)

    Pesente, Silvia; Nebbia, Giancarlo; Lunardon, Marcello; Viesti, Giuseppe E-mail: giuseppe.viesti@pd.infn.it; Sudac, Davorin; Nad, Karlo; Blagus, Sasha; Valkovic, Vladivoj

    2004-10-01

    Non-destructive inspection of luggage has been simulated in laboratory conditions by using a 14 MeV tagged neutron beam and BaF{sub 2} scintillation detectors (Tagged Neutron Inspection System, TNIS). The tagged neutron beam is produced by detecting the associated alpha particle emitted in the D+T reaction by means of a YAP:Ce scintillator. The TNIS intrinsic time resolution has been measured to be {delta}t=0.9 ns [FWHM], which allows inspection of a minimum voxel of 5 cm depth along the neutron flight path. This characteristic is demonstrated by identifying graphite and water samples hidden inside a hard plastic suitcase filled with background material. Finally, explosive devices such as small anti-personnel or anti-tank landmines have been inspected when placed inside the suitcase. In the case of relatively large explosive objects such as an anti-tank landmine, the system is capable of testing directly the TNT charge inside the device, separating this material from the external plastic case. Further developments of the TNIS concept are discussed.

  14. Measuring the neutron star equation of state using X-ray timing

    CERN Document Server

    Watts, Anna L; Chakrabarty, Deepto; Feroci, Marco; Hebeler, Kai; Israel, Gianluca; Lamb, Frederick K; Miller, M Coleman; Morsink, Sharon; Özel, Feryal; Patruno, Alessandro; Poutanen, Juri; Psaltis, Dimitrios; Schwenk, Achim; Steiner, Andrew W; Stella, Luigi; Tolos, Laura; van der Klis, Michiel

    2016-01-01

    One of the primary science goals of the next generation of hard X-ray timing instruments is to determine the equation of state of the matter at supranuclear densities inside neutron stars, by measuring the radius of neutron stars with different masses to accuracies of a few percent. Three main techniques can be used to achieve this goal. The first involves waveform modelling. The flux we observe from a hotspot on the neutron star surface offset from the rotational pole will be modulated by the star's rotation, giving rise to a pulsation. Information about mass and radius is encoded into the pulse profile via relativistic effects, and tight constraints on mass and radius can be obtained. The second technique involves characterising the spin distribution of accreting neutron stars. The most rapidly rotating stars provide a very clean constraint, since the mass-shedding limit is a function of mass and radius. However the overall spin distribution also provides a guide to the torque mechanisms in operation and th...

  15. CERN: Making CLIC tick

    International Nuclear Information System (INIS)

    While the Large Hadron Collider (LHC) scheme for counter-rotating proton beams in a new superconducting ring to be built in CERN's existing 27-kilometre LEP tunnel is being pushed as the Laboratory's main construction project for the 1990s, research and development continues in parallel for an eventual complementary attack on new physics frontiers with CERN's Linear Collider - CLIC - firing TeV electron and positron beams at each other

  16. Cern Women's Club

    CERN Multimedia

    Cern Women's Club

    2014-01-01

      CERN WOMEN’S CLUB   Coffee Morning Tuesday 10th  June 2014, 12:30   Annual Club Lunch at the restaurant “Le Coq Rouge” in St-Genis-Pouilly Those interested in helping should come along. New arrivals and all members are cordially invited. You can enrol for membership, renew membership, find out about and sign up for our activities. Visit our website: http://web.cern.ch/Club-WomensClub/

  17. Cern women's club

    CERN Document Server

    Club des cernoises

    2014-01-01

    CERN WOMEN’S CLUB Coffee Morning Tuesday 13th  May 2014, 9:30 Bldg 504,  (Restaurant No 2 – DSR) 1st Floor, Club Room 3   Annual General Meeting Those interested in helping should come along. New arrivals and all members are cordially invited. You can enrol for membership, renew membership, find out about and sign up for our activities. Visit our website: http://cern.ch/Club-WomensClub/

  18. CERN, Accelerating Science

    CERN Multimedia

    De Melis, Cinzia

    2015-01-01

    What is the Universe made of? Where did it come from, where is it going and why does it behave the way it does? These are some of the questions that CERN set out to address when a small number of pioneering scientists created Europe’s first scientific international organization. Founded in 1954, in the aftermath of the Second World War, CERN is not only a first-class centre for fundamental research but also a pioneering adventure in international collaboration.

  19. The CERN's year

    International Nuclear Information System (INIS)

    CERN, the European organization for nuclear research, has just celebrated its fifty years of existence. Its first goal was to counterbalance the migration of physics scientists towards the USA by the creation of a physics laboratory gathering scientists from the different European countries. Today, the CERN's mission has changed and has overcome all the expectations of its founders. In 2008, it will become, with the LHC (Large Hadron Collider), the biggest particle accelerator in the world. The CERN employs about 3000 physicists, engineers, technicians and workers. There is also 6500 people from 80 different countries who use the CERN's facilities during the year. The CERN is controlled by 20 European member states and 6 observer countries, and 20 non-member countries participate to the programs in progress. The CERN's power comes from its international and cosmopolitan spirit. The whole most famous physicists of the world can work together for the progress of science and for a better understanding of matter, of its interactions and of our universe. Two Nobel prices of physics come from the CERN: C. Rubbia and S. Van der Meer in 1983 for the discovery of W+, W- and Z0 bosons, and G. Charpak for the development of particle detectors. One can foresee that the LHC will allow new scientific achievements, like for instance, during experiments for the quest of the famous Higgs boson. It is important also to mention that the CERN has been at the origin of several technological innovations in all technical and engineering domains in the framework of its fundamental physics researches. (J.S.)

  20. CERN: RICH dividends

    International Nuclear Information System (INIS)

    Back in 1985, when the hunt was on at CERN's proton-antiproton collider for as many W and Z particles as possible, an Athens/CERN/Uppsala/Wuppertal group had an unique chance to install a ring-imaging Cherenkov counter (RICH) in one of the twelve end-cap sectors of the big UA2 experiment and squeeze in a short run

  1. CERN Library | Agnes Chavez @ CERN | 3 May

    CERN Multimedia

    CERN Library

    2016-01-01

    Agnes Chavez is an artist and educator participating in a two-week research stay through the ATLAS Experiment at CERN.   Tuesday 3 May at 4 p.m. CERN Library (52 1-052) Artist/educator, Agnes Chavez will share video outcomes from Projecting Particles, an Art + Science + Education collaboration with ATLAS. The Sci-Art project combines the International Masterclass with Projection Art in a series of teen-led youth workshops and projection events. In this presentation Chavez will share her vision and describe the research and development behind the project, now in its third year.  For the Projecting pARTicles series of art installations she has formed an interdisciplinary team of programmers, artists, scientists and educators to investigate how we can create art and education interventions inspired by emerging particle physics theories. Chavez’s art experiments with data visualization, sound and projections to create participatory environments. She collaborates with programmers t...

  2. Yachting Club CERN

    CERN Multimedia

    Yachting Club CERN

    2010-01-01

    New President, new committee, new season The YCC General Meeting was a long time ago, November, but elected itself a new President, Alex Cerri, and a Committee with a few changes as well. It also remembered to thank outgoing President Tomasz Ładziński for his excellent leadership and personal hard work over many seasons. And then we rounded off the evening with the Closing Dinner and awards of prizes: skippers, crew-member, and photographic cultminations of a very enjoyable season. This new Committee has met a couple of times already, and planned the season carefully: check it out on http://yachting.web.cern.ch/yachting/ . We are highlighting a Winter Evening next week: see the Blog on the opening page, and join us for some insights on owning, running, sailing, an Atlantic cruiser - solo! It is also not too early to contemplate signing up for a course: not just newcomers, but those moving from the early experiences in to more demanding boats. We are planning courses very similar to the previous season, pl...

  3. CERN Courier has a new look

    CERN Multimedia

    Christine Sutton

    2011-01-01

    During more than 50 years of existence, CERN’s well-known magazine has changed several times in appearance. Now, for the first time since the 1990s, it has a new look for the new decade.   The new cover of the CERN Courier. Originally conceived as an internal newsletter, the CERN Courier first appeared in August 1959 in an edition of 8 pages with a print run of 1000. From the start it generated interest outside CERN, with its articles not only on CERN but also about particle physics around the world. The number of copies doubled in the first 6 months in response to the external demand. As CERN prepares to welcome new Member States in the coming years, it’s even more fitting that the magazine should continue to address a global readership, now totalling some 25,000 and extending throughout the many countries that have an interest in particle physics. It’s therefore important that the CERN Courier should remain appealing to this extensive audience, both visually and i...

  4. Water ingress into a casein film quantified using time-resolved neutron imaging.

    Science.gov (United States)

    Metwalli, E; Hermes, H E; Calzada, E; Kulozik, U; Egelhaaf, S U; Müller-Buschbaum, P

    2016-03-01

    The migration of water into a casein film was probed with neutron radiography. From the neutron transmission images, the evolution of the water saturation profiles was extracted. The results indicate that the water influx is dominated by imbibition but also contains a diffusional component. The time dependence of the water ingress was quantified using a diffusion-like equation previously also applied to imbibition. A water transport coefficient D = 0.9 × 10(-9) m(2) s(-1) was found. This value and direct observation of the images indicate that the time taken for a typical adhesive casein-based layer to become saturated with water is of the order of hours. PMID:26862596

  5. X-ray timing observations of the brightest neutron star LMXB Sco X-1

    Science.gov (United States)

    Yu, W.

    The observations of the brightest neutron star LMXB Sco X-1 with the Rossi X-ray timing explorer RXTE show that the components of its variability in the frequency range between 0 01 Hz to 1000 Hz are related This is unique and has been benefited from the high X-ray count rate which would only be obtained for other neutron star LMXBs with a ten times RXTE In previous studies we have found that 1 the upper kHz QPO frequency varies more than 22 Hz within the 6 Hz normal branch oscillation NBO cycle 2 the 45 Hz HBO amplitude is correlated with the phase of the 6 Hz NBO We will summarize our results obtained from further studies of Sco X-1 and other sources in these directions and discuss the underlying physics

  6. Temporary Polarisation Insert for a Time-of-Flight Neutron Reflectometer

    CERN Document Server

    Kreuzpaintner, Wolfgang; Moulin, Jean-François; Wiedemann, Birgit; Ye, Jingfan; Mayr, Sina; Paul, Amitesh; Haese, Martin; Pomm, Matthias; Böni, Peter

    2016-01-01

    The suitability of a transportable 3He-spin filter as broadband polariser for a Time-of-Flight neutron reflectometer in combination with a proposed characterisation method for 3He-spin filters is presented. Both, the experimental simplicity and the data treatment procedure for extracting the spin-up and spin-down neutron reflectivity from measurements obtained for a time dependent 3He polarisation, are shown. For benchmarking, the extraction of a very weak magnetic signal from reflectivity data, measured on the magnetic heterostructure Fe(1nm)/Cu(20nm)/Si(substrate) in an externally applied magnetic field of 30 mT is demonstrated and compared to similar measurements on Cu(20nm)/Si(substrate), which show no magnetic signal.

  7. Time-resolved small-angle neutron scattering of a micelle-to-vesicle transition

    Energy Technology Data Exchange (ETDEWEB)

    Egelhaaf, S.U. [Institut Max von Laue - Paul Langevin (ILL), 38 -Grenoble (France); Schurtenberger, P. [Eidgenoessische Technische Hochschule, Zurich (Switzerland)

    1997-04-01

    Amphiphilic molecules spontaneously self-assemble in solution to form a variety of aggregates. Only limited information is available on the kinetics of the structural transitions as well as on the existence of non-equilibrium or metastable states. Aqueous mixtures of lecithin and bile salt are very interesting biological model-systems which exhibit a spontaneous transition from polymer-like mixed micelles to vesicles upon dilution. The small-angle neutron scattering (SANS) instrument D22, with its very high neutron flux and the broad range of scattering vectors covered in a single instrumental setting, allowed us for the first time to perform time-resolved scattering experiments in order to study the micelle-to-vesicle transition. The temporal evolution of the aggregate structures were followed and detailed information was obtained even on molecular length-scales. (author). 5 refs.

  8. CREATIVE COLLISIONS: ARTS @CERN

    CERN Document Server

    CERN. Geneva

    2012-01-01

    In 2000, CERN hosted Signatures of the Invisible – one of the landmark initiatives in arts and science. In 2012, CERN is now initiating its own science/arts programme Collide@CERN in different arts disciplines. The first of these is in digital arts, and the international competition to find the winning artist is called the Prix Ars Electronica Collide@CERN. It was announced September 2011 at CERN’s first collaboration with an international arts festival – Ars Electronica in Linz. The competition attracted over 395 entries from 40 countries around the world. The winning artist, Julius Von Bismarck, will begin his two month residency here at CERN next month. Ariane Koek who leads on this initiative, discusses the residency programme, as well as the background about Art@CERN. History has shown that particle physics and the arts are great inspiration partners. The publication of the paper by Max Planck which gave birth to quantum mechanics as well as those by Einstein, heavily influenced some of the grea...

  9. Sharing resources@CERN

    CERN Multimedia

    2002-01-01

    The library is launching a 'sharing resources@CERN' campaign, aiming to increase the library's utility by including the thousands of books bought by individual groups at CERN. This will improve sharing of information among CERN staff and users. Until now many people were unaware that copies of the same book (or standard, or journal) are often held not only by the library but by different divisions. (Here Eduardo Aldaz, from the PS division, and Isabel Bejar, from the ST division, read their divisional copies of the same book.) The idea behind the library's new sharing resources@CERN' initiative is not at all to collect the books in individual collections at the CERN library, but simply to register them in the Library database. Those not belonging to the library will in principle be unavailable for loan, but should be able to be consulted by anybody at CERN who is interested. "When you need a book urgently and it is not available in the library,' said PS Division engineer Eduardo Aldaz Carroll, it is a sham...

  10. CERN Relay Race

    CERN Multimedia

    Running Club

    2010-01-01

    This year’s CERN Relay Race will take place around the Meyrin site on Thursday 20th May at 12h00. This annual event is for teams of 6 runners covering distances of 1000m, 800m, 800m, 500m, 500m and 300m respectively. Teams may be entered in the Seniors, Veterans, Ladies, Mixed or Open categories. The registration fee is 10 CHF per runner, and each runner receives a souvenir prize. As usual, there will be a programme of entertainments from 12h in the arrival area, in front of the Restaurant no. 1. Drinks, food, CERN club information and music will be available for the pleasure of both runners and spectators. The race starts at 12h15, with results and prize giving at 13:15.   For details of the race, and of how to sign up a team, please visit: https://espace.cern.ch/Running-Club/CERN-Relay The event is organised by the CERN Running Club with the support of the CERN Staff Association.  

  11. CERN In Focus

    CERN Multimedia

    CERN audiovisual service

    2008-01-01

    First edition 2008 of Cern in Focus. On behalf of the audiovisual team, a selection of the latest videos filmed at CERN. Every six weeks, we will bring you the latest in CERN's activities, from LHC start up to the Computing Grid, featuring the experiments and many other goings-on at CERN. The agenda of this first edition of CERN in Focus features the visit of the prime minister of Malta, Lawrence Gonzi... CMS and the final descent of the YE-1 end cap... The departure of UA1 magnets to Japan... The start up of sectors 4 and 5... And finally, in our sports round up... We'll talk about football. New in brief this month... The final bolt is in place : On 7th November, in the bowels of the LHC tunnel, CERN's Director General Robert Aymar tightened a gold-plated bolt for the last arc interconnection of sector 1-2. This symbolic gesture marks the completion of all the arc interconnections of the LHC. Last welding work: it was never going to be an easy task. On this day last year just one sector had been completed,...

  12. Measurement of the angular distribution of fission fragments using a PPAC assembly at CERN nTOF

    International Nuclear Information System (INIS)

    A fission reaction chamber based on Parallel Plate Avalanche Counters (PPACs) was built for measuring angular distributions of fragments emitted in neutron-induced fission of actinides at the neutron beam available at the Neutron Time-Of-Flight (nTOF) facility at CERN. The detectors and the samples were tilted 45° with respect to the neutron beam direction to cover all the possible values of the emission angle of the fission fragments. The main features of this setup are discussed and results on the fission fragment angular distribution are provided for the 232Th(n,f) reaction around the fission threshold. The results are compared with the available data in the literature, demonstrating the good capabilities of this setup

  13. Measurement of the angular distribution of fission fragments using a PPAC assembly at CERN n_TOF

    CERN Document Server

    Tarrío, D; Audouin, L; Duran, I; Paradela, C; Tassan-Got, L; Le Naour, C; Bacri, C O; Petitbon, V; Mottier, J; Caamano, M; Altstadt, S; Andrzejewski, J; Barbagallo, M; Bécares, V; Bečvář, F; Belloni, F; Berthoumieux, E; Billowes, J; Boccone, V; Bosnar, D; Brugger, M; Calviani, M; Calviño, F; Cano-Ott, D; Carrapiço, C; Cerutti, F; Chiaveri, E; Chin, M; Colonna, N; Cortés, G; Cértes-Giraldo, M A; Diakaki, M; Domingo-Pardo, C; Dzysiuk, N; Eleftheriadis, C; Ferrari, A; Fraval, K; Ganesan, S; García, A R; Giubrone, G; Gómez-Hornillos, M B; Gonçalves, I F; González-Romero, E; Griesmayer, E; Guerrero, C; Gunsing, F; Gurusamy, P; Jenkins, D G; Jericha, E; Kadi, Y; Käppeler, F; Karadimos, D; Koehler, P; Kokkoris, M; Krtička, M; Kroll, J; Langer, C; Lederer, C; Leeb, H; Losito, R; Manousos, A; Marganiec, J; Martínez, T; Massimi, C; Mastinu, P F; Mastromarco, M; Meaze, M; Mendoza, E; Mengoni, A; Milazzo, P M; Mingrone, F; Mirea, M; Mondalaers, W; Pavlik, A; Perkowski, J; Plompen, A; Praena, J; Quesada, J M; Rauscher, T; Reifarth, R; Riego, A; Roman, F; Rubbia, C; Sarmento, R; Schillebeeckx, P; Schmidt, S; Tagliente, G; Tain, J L; Tsinganis, A; Valenta, S; Vannini, G; Variale, V; Vaz, P; Ventura, A; Versaci, R; Vermeulen, M J; Vlachoudis, V; Vlastou, R; Wallner, A; Ware, T; Weigand, M; Weiß, C; Wright, T J; Žugec, P

    2014-01-01

    A fission reaction chamber based on Parallel Plate Avalanche Counters (PPACs) was built for measuring angular distributions of fragments emitted in neutron-induced fission of actinides at the neutron beam available at the Neutron Time-Of-Flight (n_TOF) facility at CERN. The detectors and the samples were tilted 45 1 with respect to the neutron beam direction to cover all the possible values of the emission angle of the fission fragments. The main features of this setup are discussed and results on the fission fragment angular distribution are provided for the 232 Th(n,f) reaction around the fission threshold. The results are compared with the available data in the literature, demonstrating the good capabilities of this setup

  14. New life for CERN's first accelerator

    CERN Document Server

    Anaïs Schaeffer

    2011-01-01

    Building 300 right in the middle of the CERN site houses a special "antique": the Laboratory's very first accelerator. After several years in the wilderness following its decommissioning in 1990, the Synchrocyclotron is set to take on a new lease of life in the near future, this time as a visitor attraction.   The Synchrocyclotron as it was in 1975; it will be restored to this configuration for public viewing. The Synchrocyclotron (SC) began operation in 1957, two years before the PS was commissioned. Running at an energy of 600 MeV and producing beams of protons, neutrons, muons and pions, it helped to further research in the nuclear physics field for no fewer than 33 years, providing beams for various decay experiments as well as the muon capture experiment (*). Since the SC was decommissioned in 1990, three of its four buildings (160, 161 and 301) have been converted into offices for members of the ALICE collaboration, but the shielded hall housing the machine it...

  15. Deformation dynamics study of a wrought magnesium alloy by real-time in situ neutron diffraction

    International Nuclear Information System (INIS)

    The deformation dynamics and the effect of deformation history on plastic deformation in a wrought magnesium alloy at room temperature have been studied by real-time in situ neutron diffraction measurements under a continuous loading condition. The experimental results reveal that no detwinning occurred during unloading after compression and even in an elastic region during reverse tension. It is found that the serration behavior is closely related to the twinning- and detwinning-dominated deformation

  16. Time resolved analysis of water drainage in porous asphalt concrete using neutron radiography.

    Science.gov (United States)

    Poulikakos, L D; Sedighi Gilani, M; Derome, D; Jerjen, I; Vontobel, P

    2013-07-01

    Porous asphalt as a road surface layer controls aquaplaning as rain water can drain through its highly porous structure. The process of water drainage through this permeable layer is studied using neutron radiography. Time-resolved water configuration and distribution within the porous structure are reported. It is shown that radiography depicts the process of liquid water transport within the complex geometry of porous asphalt, capturing water films, filled dead end pores and water islands. PMID:23500651

  17. Oscillations of hot, young neutron stars: Gravitational wave frequencies and damping times

    OpenAIRE

    Burgio, G.F.; Ferrari, V.; Gualtieri, L.; Schulze, H. J.

    2011-01-01

    We study how the frequencies and damping times of oscillations of a newly born, hot proto-neutron star depend on the physical quantities which characterize the star quasi-stationary evolution which follows the bounce. Stellar configurations are modeled using a microscopic equation of state obtained within the Brueckner-Hartree-Fock, nuclear many-body approach, extended to the finite-temperature regime. We discuss the mode frequency behaviour as function of the lepton composition, and of the e...

  18. The response time analysis of high log neutron flux rate for heavy water reactors

    International Nuclear Information System (INIS)

    The heavy water reactor such as Wolssung no. 1 has a protection/safety system named special safety system. The system has four safety systems ; shutdown no. 1, shutdown no. 2, emergency core cooling system and containment system. In this paper, the response time of high log neutron flux rate, one of the reactor trip loops of shutdown no.1/no.2, was analysed based on the description of final safety analysis report and compared to the plant measurement

  19. Parameters’ Covariance in Neutron Time of Flight Analysis – Explicit Formulae

    Energy Technology Data Exchange (ETDEWEB)

    Odyniec, M. [NSTec; Blair, J. [NSTec

    2014-12-01

    We present here a method that estimates the parameters’ variance in a parametric model for neutron time of flight (NToF). The analytical formulae for parameter variances, obtained independently of calculation of parameter values from measured data, express the variances in terms of the choice, settings, and placement of the detector and the oscilloscope. Consequently, the method can serve as a tool in planning a measurement setup.

  20. People and things. CERN Courier, Dec 1991, v. 31(10)

    International Nuclear Information System (INIS)

    The article reports on achievements of various people, staff changes and position opportunities within the CERN organization and contains news updates on upcoming or past events: ; The pulsed muon facility at the UK Rutherford Appleton Laboratory's ISIS neutron source is to be substantially upgraded under the European Commission's Large Installations Plan. ; On 1 November at CERN, a cooperation agreement was signed which provides a framework for Australia and CERN to develop reciprocal scientific and technical cooperation