WorldWideScience

Sample records for external neutron beam

  1. Peripheral photon and neutron doses from prostate cancer external beam irradiation.

    Science.gov (United States)

    Bezak, Eva; Takam, Rundgham; Marcu, Loredana G

    2015-12-01

    Peripheral photon and neutron doses from external beam radiotherapy (EBRT) are associated with increased risk of carcinogenesis in the out-of-field organs; thus, dose estimations of secondary radiation are imperative. Peripheral photon and neutron doses from EBRT of prostate carcinoma were measured in Rando phantom. (6)LiF:Mg,Cu,P and (7)LiF:Mg,Cu,P glass-rod thermoluminescence dosemeters (TLDs) were inserted in slices of a Rando phantom followed by exposure to 80 Gy with 18-MV photon four-field 3D-CRT technique. The TLDs were calibrated using 6- and 18-MV X-ray beam. Neutron dose equivalents measured with CR-39 etch-track detectors were used to derive readout-to-neutron dose conversion factor for (6)LiF:Mg,Cu,P TLDs. Average neutron dose equivalents per 1 Gy of isocentre dose were 3.8±0.9 mSv Gy(-1) for thyroid and 7.0±5.4 mSv Gy(-1) for colon. For photons, the average dose equivalents per 1 Gy of isocentre dose were 0.2±0.1 mSv Gy(-1) for thyroid and 8.1±9.7 mSv Gy(-1) for colon. Paired (6)LiF:Mg,Cu,P and (7)LiF:Mg,Cu,P TLDs can be used to measure photon and neutron doses simultaneously. Organs in close proximity to target received larger doses from photons than those from neutrons whereas distally located organs received higher neutron versus photon dose. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  2. The status of neutron beam utilization in Korea

    International Nuclear Information System (INIS)

    Shim, Hae-Seop; Lee, Chang-Hee; Seong, Baek-Seok; Lee, Jeong-Soo

    1999-01-01

    HANARO (30 MWth) at Korea Atomic Energy Research Institute (KAERI), which reached its first criticality on February 1995, is the multi-purpose research reactor for the application of reactor radiation in a variety of fields such as physics and materials science, irradiation technology, biomedical technology, and neutron activation analysis. For the neutron beam research, seven horizontal beam tubes of different types are available, and HANARO has performed its development plan for a basic set of neutron beam instruments since 1992. A High Resolution Powder Diffractometer (HRPD) and a Neutron Radiography Facility (NRF) has been installed and operated since 1997 and 1996 each. A Four Circle Diffractometer (FCD) and a Small Angle Neutron Spectrometer (SANS) will be operational on 1999 and in 2000 respectively, and a Polarized Neutron Spectrometer (PNS) in 2001. SANS at CN (Cold Neutron) beam tube will be operated using liquid nitrogen cooled Be filter until the cold neutron source is made available. Then, it will be moved to a guide laboratory with proper modification. Research works using the instruments in operation started by internal and external users since their full operation and have been rapidly increasing. Most in-house resources available are being used for on-going development of instruments due to rapidly increasing demands of external users nationwide. In addition to above instruments, a Triple Axis Spectrometer (TAS) and a Neutron Reflectometer which have been strongly requested by external users from universities and industries are under discussion. Then, HANARO will provide the best combination of neutron instruments to meet national research demands and international collaborations, and will be well prepared for future researches by cold neutrons. (author)

  3. Study of the RP-10 reactor neutron beam applied to the neutron radiography

    International Nuclear Information System (INIS)

    Zegarra, Manuel; Lopez, Alcides

    2013-01-01

    We have studied the RP-10 reactor radial neutron beam No. 3, which is used for neutron radiographies, by comparing radiograph's with and without the inner duct, and neutron flux determination with in flakes along the external duct, being the presence of photons creating signals at comparable levels of neutron effects, which reduce the quality of the analysis, values around 10 6 and 10 4 n/cm 2 s for thermal and epithermal flux were obtained respectively. It is recommended evaluate the design of the internal duct which presents strong photon emission. (authors).

  4. Improvements to the internal and external antenna H(-) ion sources at the Spallation Neutron Source.

    Science.gov (United States)

    Welton, R F; Dudnikov, V G; Han, B X; Murray, S N; Pennisi, T R; Pillar, C; Santana, M; Stockli, M P; Turvey, M W

    2014-02-01

    The Spallation Neutron Source (SNS), a large scale neutron production facility, routinely operates with 30-40 mA peak current in the linac. Recent measurements have shown that our RF-driven internal antenna, Cs-enhanced, multi-cusp ion sources injects ∼55 mA of H(-) beam current (∼1 ms, 60 Hz) at 65-kV into a Radio Frequency Quadrupole (RFQ) accelerator through a closely coupled electrostatic Low-Energy Beam Transport system. Over the last several years a decrease in RFQ transmission and issues with internal antennas has stimulated source development at the SNS both for the internal and external antenna ion sources. This report discusses progress in improving internal antenna reliability, H(-) yield improvements which resulted from modifications to the outlet aperture assembly (applicable to both internal and external antenna sources) and studies made of the long standing problem of beam persistence with the external antenna source. The current status of the external antenna ion source will also be presented.

  5. Dosimetry of clinical neutron and proton beams: An overview of recommendations

    International Nuclear Information System (INIS)

    Vynckier, S.

    2004-01-01

    Neutron therapy beams are obtained by accelerating protons or deuterons on Beryllium. These neutron therapy beams present comparable dosimetric characteristics as those for photon beams obtained with linear accelerators; for instance, the penetration of a p(65) + Be neutron beam is comparable with the penetration of an 8 MV photon beam. In order to be competitive with conventional photon beam therapy, the dosimetric characteristics of the neutron beam should therefore not deviate too much from the photon beam characteristics. This paper presents a brief summary of the neutron beams used in radiotherapy. The dosimetry of the clinical neutron beams is described. Finally, recent and future developments in the field of physics for neutron therapy is mentioned. In the last two decades, a considerable number of centres have established radiotherapy treatment facilities using proton beams with energies between 50 and 250 MeV. Clinical applications require a relatively uniform dose to be delivered to the volume to be treated, and for this purpose the proton beam has to be spread out, both laterally and in depth. The technique is called 'beam modulation' and creates a region of high dose uniformity referred to as the 'spread-out Bragg peak'. Meanwhile, reference dosimetry in these beams had to catch up with photon and electron beams for which a much longer tradition of dosimetry exists. Proton beam dosimetry can be performed using different types of dosemeters, such as calorimeters, Faraday cups, track detectors and ionisation chambers. National standard dosimetry laboratories will, however, not provide a standard for the dosimetry of proton beams. To achieve uniformity on an international level, the use of an ionisation chamber should be considered. This paper reviews and summarises the basic principles and recommendations for the absorbed dose determination in a proton beam, utilising ionisation chambers calibrated in terms of absorbed dose to water. These recommendations

  6. Neutron Beam Filters

    International Nuclear Information System (INIS)

    Adib, M.

    2011-01-01

    The purpose of filters is to transmit neutrons with selected energy, while remove unwanted ones from the incident neutron beam. This reduces the background, and the number of spurious. The types of commonly used now-a-day neutron filters and their properties are discussed in the present work. There are three major types of neutron filters. The first type is filter of selective thermal neutron. It transmits the main reflected neutrons from a crystal monochromate, while reject the higher order contaminations accompanying the main one. Beams coming from the moderator always contain unwanted radiation like fast neutrons and gamma-rays which contribute to experimental background and to the biological hazard potential. Such filter type is called filter of whole thermal neutron spectrum. The third filter type is it transmits neutrons with energies in the resonance energy range (En . 1 KeV). The main idea of such neutron filter technique is the use of large quantities of a certain material which have the deep interference minima in its total neutron cross-section. By transmitting reactor neutrons through bulk layer of such material, one can obtain the quasimonochromatic neutron lines instead of white reactor spectrum.

  7. Study on neutron beam probe. Study on the focused neutron beam

    Energy Technology Data Exchange (ETDEWEB)

    Kotajima, Kyuya; Suzuki, K.; Fujisawa, M.; Takahashi, T.; Sakamoto, I. [Tohoku Univ., Sendai (Japan). Faculty of Engineering; Wakabayashi, T.

    1998-03-01

    A monoenergetic focused neutron beam has been produced by utilizing the endoenergetic heavy ion reactions on hydrogen. To realize this, the projectile heavy ion energy should be taken slightly above the threshold energy, so that the excess energy converted to the neutron energy should be very small. In order to improve the capability of the focused neutron beam, some hydrogen stored metal targets have also been tested. Separating the secondary heavy ions (associated particles) from the primary ions (accelerated particles) by using a dipole magnet, a rf separator, and a particle identification system, we could directly count the produced neutrons. This will leads us to the possibility of realizing the standard neutron field which had been the empty dream of many neutron-related researchers in the world. (author)

  8. Basic research of neutron radiography using cold neutron beam

    International Nuclear Information System (INIS)

    Oda, Masahiro; Tamaki, Masayoshi; Tasaka, Kanji

    1995-01-01

    As the result of demanding high quality images, now the nuclear reactors which can supply stably intense neutron beam have become the most general neutron source for radiography. For the purpose, mostly thermal neutrons have been used, but it is indispensable to use other neutrons than thermal neutrons for advancing neutron radiography technology and expanding the application fields. The radiography using cold neutrons is most behind in the development because the suitable neutron source was not available in Japan. The neutron sources for exclusively obtaining intense cold neutron beam were installed in the Kyoto University reactor in 1986 and in the JRR-3M of Japan Atomic Energy Research Institute in 1991. Basically as neutron energy lowers, the cross section of substances increases. In certain crystalline substances, the Bragg cutoff arises. The removal of scattered neutrons, the measurement of parallelism of beam and the relation of the thickness of objects with the transmissivity of cold neutrons are described. The imaging by TV method and the cold neutron CT in the CNRF and the simplified neutron CT by film method are reported. (K.I.)

  9. BR2 reactor neutron beams

    International Nuclear Information System (INIS)

    Neve de Mevergnies, M.

    1977-01-01

    The use of reactor neutron beams is becoming increasingly more widespread for the study of some properties of condensed matter. It is mainly due to the unique properties of the ''thermal'' neutrons as regards wavelength, energy, magnetic moment and overall favorable ratio of scattering to absorption cross-sections. Besides these fundamental reasons, the impetus for using neutrons is also due to the existence of powerful research reactors (such as BR2) built mainly for nuclear engineering programs, but where a number of intense neutron beams are available at marginal cost. A brief introduction to the production of suitable neutron beams from a reactor is given. (author)

  10. Neutron beam applications

    International Nuclear Information System (INIS)

    Lee, Chang Hee; Lee, J. S.; Seong, B. S.

    2000-05-01

    For the materials science by neutron technique, the development of the various complementary neutron beam facilities at horizontal beam port of HANARO and the techniques for measurement and analysis has been performed. High resolution powder diffractometer, after the installation and performance test, has been opened and used actively for crystal structure analysis, magnetic structure analysis, phase transition study, etc., since January 1998. The main components for four circle diffractometer were developed and, after performance test, it has been opened for crystal structure analysis and texture measurement since the end of 1999. For the small angle neutron spectrometer, the main component development and test, beam characterization, and the preliminary experiment for the structure study of polymer have been carried out. Neutron radiography facility, after the precise performance test, has been used for the non-destructive test of industrial component. Addition to the development of main instruments, for the effective utilization of those facilities, the scattering techniques relating to quantitative phase analysis, magnetic structure analysis, texture measurement, residual stress measurement, polymer study, etc, were developed. For the neutron radiography, photographing and printing technique on direct and indirect method was stabilized and the development for the real time image processing technique by neutron TV was carried out. The sample environment facilities for low and high temperature, magnetic field were also developed

  11. A neutron beam polarizer for study of parity violation in neutron-nucleus interactions

    International Nuclear Information System (INIS)

    Penttilae, S.I.; Bowman, J.D.; Frankle, C.M.; Seestrom, S.J.; Yen, Yi-Fen; Delheij, P.P.J.; Haase, D.G.; Postma, H.

    1994-01-01

    A dynamically-polarized proton target operating at 5 Tesla and 1 K has been built to, neutron beam for studies of parity violation in compound-nuclear resonances. Nearly 0.9 proton polarization was obtained in an electron-beam irradiated ammonia target. This was used to produce a neutron beam polarization of 0.7 at epithermal energies. The combination of the polarized proton target and the LANSCE spallation neutron source produces the most intense pulsed polarized epithermal neutron beam in the world. The neutron-beam polarizer is described and methods to determine neutron beam polarization are presented

  12. Calculated intensity of high-energy neutron beams

    International Nuclear Information System (INIS)

    Mustapha, B.; Nolen, J.A.; Back, B.B.

    2004-01-01

    The flux, energy and angular distributions of high-energy neutrons produced by in-flight spallation and fission of a 400 MeV/A 238 U beam and by the break-up of a 400 MeV/A deuteron beam are calculated. In both cases very intense secondary neutron beams are produced, peaking at zero degrees, with a relatively narrow energy spread. Such secondary neutron beams can be produced with the primary beams from the proposed rare isotope accelerator driver linac. The break-up of a 400 kW deuteron beam on a liquid-lithium target can produce a neutron flux of >10 10 neutrons/cm 2 /s at a distance of 10 m from the target

  13. SU-E-T-542: Measurement of Internal Neutrons for Uniform Scanning Proton Beams

    Energy Technology Data Exchange (ETDEWEB)

    Islam, M; Ahmad, S [University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma (United States); Zheng, Y; Rana, S [Procure Proton Therapy Center, Oklahoma City, OK (United States); Collums, T [University of Iowa Hospitals and Clinics, Iowa City, IA (United States); Monsoon, J; Benton, E [Oklahoma State University, Stillwater, OK (United States)

    2015-06-15

    Purpose: In proton radiotherapy, the production of neutrons is a wellknown problem since neutron exposure can lead to increased risk of secondary cancers later in the patient’s lifetime. The assessment of neutron exposure is, therefore, important for the overall quality of proton radiotherapy. This study investigates the secondary neutrons created inside the patient from uniform scanning proton beams. Methods: Dose equivalent due to secondary neutrons was measured outside the primary field as a function of distance from beam isocenter at three different angles, 45, 90 and 135 degree, relative to beam axis. Plastic track nuclear detector (CR-39 PNTD) was used for the measurement of neutron dose. Two experimental configurations, in-air and cylindrical-phantom, were designed. In a cylindrical-phantom configuration, a cylindrical phantom of 5.5 cm diameter and 35 cm long was placed along the beam direction and in an in-air configuration, no phantom was used. All the detectors were placed at nearly identical locations in both configurations. Three proton beams of range 5 cm, 18 cm, and 32 cm with 4 cm modulation width and a 5 cm diameter aperture were used. The contribution from internal neutrons was estimated from the differences in measured dose equivalent between in-air and cylindrical-phantom configurations at respective locations. Results: The measured ratio of neutron dose equivalent to the primary proton dose (H/D) dropped off with distance and ranged from 27 to 0.3 mSv/Gy. The contribution of internal neutrons near the treatment field edge was found to be up to 64 % of the total neutron exposure. As the distance from the field edge became larger, the external neutrons from the nozzle appear to dominate and the internal neutrons became less prominent. Conclusion: This study suggests that the contribution of internal neutrons could be significant to the total neutron dose equivalent.

  14. A neutron beam facility at Spiral-2

    Energy Technology Data Exchange (ETDEWEB)

    Ledoux, X.; Bauge, E.; Belier, G.; Ethvignot, T.; Taieb, J.; Varignon, C. [CEA Bruyeres-le-Chatel, DIF, 91 (France); Andriamonje, S.; Dore, D.; Dupont, E.; Gunsing, F.; Ridikas, D.; Takibayev, A. [CEA Saclay, DSM/IRFU/SPhN, 91 - Gif-sur-Yvette (France); Blideanu, V. [CEA Saclay, DSM/IRFU/Senac, 91 - Gif-sur-Yvette (France); Aiche, M.; Barreau, G.; Czajkowski, S.; Jurado, B. [Centre d' Etudes Nucleaires de Bordeaux Gradignan, 33 (France); Ban, G.; Lecolley, F.R.; Lecolley, J.F.; Lecouey, J.L.; Marie, N.; Steckmeyer, J.C. [LPC, 14 - Caen (France); Dessagne, P.; Kerveno, M.; Rudolf, G. [IPHC, 57 - Strasbourg (France); Bem, P.; Mrazek, J.; Novak, J. [NPI, Rez (Czech Republic); Blomgren, J.; Pomp, S. [Uppsala Univ., Dept. of Physics and Astronomy (Sweden); Fischer, U.; Herber, S.; Simakov, S.P. [FZK, Karlsruhe (Germany); Jacquot, B.; Rejmund, F. [GANIL, 14 - Caen (France); Avrigeanu, M.; Avrigeanu, V.; Borcea, C.; Negoita, F.; Petrascu, M. [NIPNE, Bucharest (Romania); Oberstedt, S.; Plompen, A.J.M. [JRC/IRMM, Geel (Belgium); Shcherbakov, O. [PNPI, Gatchina (Russian Federation); Fallot, M. [Subatech, 44 - Nantes (France); Smith, A.G.; Tsekhanovich, I. [Manchester Univ., Dept. of Physics and Astronomy (United Kingdom); Serot, O.; Sublet, J.C. [CEA Cadarache, DEN, 13 - Saint-Paul-lez-Durance (France); Perrot, L.; Tassan-Got, L. [IPNO, 91 - Orsay (France); Caillaud, T.; Giot, L.; Landoas, O.; Ramillon, J.M.; Rosse, B.; Thfoin, I. [CIMAP, 14 - Caen (France); Balanzat, E.; Bouffard, S.; Guillous, S.; Oberstedt, A. [Orebro Univ. (Sweden)

    2009-07-01

    The future Spiral-2 facility, dedicated to the production of intense radioactive ion beams, is based on a high-power superconducting driver Linac, delivering high-intensity deuteron, proton and heavy ion beams. These beams are particularly well suited to the production of neutrons in the 100 keV- 40 MeV energy range, a facility called 'Neutrons for Science' (NFS) will be built in the LINAG Experimental Area (LEA). NFS, operational in 2012, will be composed of a pulsed neutron beam for in-flight measurements and irradiation stations for activation measurements and material studies. Thick C and Be converters and a deuteron beam will produce an intense continuous neutron spectrum, while a thin {sup 7}Li target and a proton beam allow to generate quasi-mono-energetic neutrons. In the present work we show how the primary ion beam characteristics (energy, time resolution and intensity) are adequate to create a neutron time-of-flight facility delivering intense neutron fluxes in the 100 keV-40 MeV energy range. Irradiation stations for neutron, proton and deuteron reactions will also allow to perform cross-section measurements by means of the activation technique. Light-ion beams will be used to study radiation damage effects on materials for the nuclear industry. (authors)

  15. A neutron beam polarizer for study of parity violation in neutron-nucleus interactions

    International Nuclear Information System (INIS)

    Penttilae, S.I.; Bowman, J.D.; Delheij, P.P.; Frankle, C.M.; Haase, D.G.; Postma, H.; Seestrom, S.J.; Yen, Y.

    1995-01-01

    A dynamically-polarized proton target operating at 5 Tesla and 1 K has been built to polarize an epithermal neutron beam for studies of parity violation in compound-nuclear resonances. Nearly 0.9 proton polarization was obtained in an electron-beam irradiated ammonia target. This was used to produce a neutron beam polarization of 0.7 at epithermal energies. The combination of the polarized proton target and the LANSCE spallation neutron source produces the most intense pulsed polarized epithermal neutron beam in the world. The neutron-beam polarizer is described and methods to determine neutron beam polarization are presented. copyright 1995 American Institute of Physics

  16. Neutronic analysis of JET external neutron monitor response

    Energy Technology Data Exchange (ETDEWEB)

    Snoj, Luka, E-mail: luka.snoj@ijs.si [Reactor Physics Division, Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana (Slovenia); Lengar, Igor; Čufar, Aljaž [Reactor Physics Division, Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana (Slovenia); Syme, Brian; Popovichev, Sergey [Culham Centre for Fusion Energy, Culham Science Centre, Abingdon, OX14 3DB, United Kingdom (United Kingdom); Batistoni, Paola [ENEA C. R. Frascati, via E. Fermi 45, 00044 Frascati, Roma (Italy); Conroy, Sean [VR Association, Uppsala University, Department of Physics and Astronomy, PO Box 516, SE-75120 Uppsala (Sweden)

    2016-11-01

    Highlights: • We model JET tokamak containing JET remote handling system. • We investigate effect of remote handling system on external neutron monitor response. • Remote handling system correction factors are calculated. • Integral correction factors are relatively small, i.e up to 8%. - Abstract: The power output of fusion devices is measured in terms of the neutron yield which relates directly to the fusion yield. JET made a transition from Carbon wall to ITER-Like Wall (Beryllium/Tungsten/Carbon) during 2010–11. Absolutely calibrated measurement of the neutron yield by JET neutron monitors was ensured by direct measurements using a calibrated {sup 252}Cf neutron source (NS) deployed by the in-vessel remote handling system (RHS) inside the JET vacuum vessel. Neutronic calculations were required in order to understand the neutron transport from the source in the vacuum vessel to the fission chamber detectors mounted outside the vessel on the transformer limbs of the tokamak. We developed a simplified computational model of JET and the JET RHS in Monte Carlo neutron transport code MCNP and analyzed the paths and structures through which neutrons reach the detectors and the effect of the JET RHS on the neutron monitor response. In addition we performed several sensitivity studies of the effect of substantial massive structures blocking the ports on the external neutron monitor response. As the simplified model provided a qualitative picture of the process only, some calculations were repeated using a more detailed full 3D model of the JET tokamak.

  17. Non-classical neutron beams for fundamental and solid state research

    International Nuclear Information System (INIS)

    Rauch, H.

    2008-01-01

    The curious dual nature of the neutron, sometimes a particle, sometimes a wave, is wonderfully manifested in the various non-local interference and quantum contextuality effects observed in neutron interferometry. Non-classical states may become useful for novel fundamental and solid state research. Here we discuss unavoidable quantum losses as they appear in neutron phase-echo and spin rotation experiments and we show how entanglement effects in a single particle system demonstrate quantum contextuality. In all cases of interactions, parasitic beams are produced which cannot be recombined completely with the original beam. This means that a complete reconstruction of the original state would, in principle, be impossible which causes a kind of intrinsic irreversibility. Even small interaction potentials can have huge effects when they are applied in quantum Zeno-like experiments. Recently, it has been shown that an entanglement between external and internal degrees of freedom exists even in single particle systems. This contextuality phenomenon also shows that a quantum system carries much more information than usually extracted. The path towards advanced neutron quantum optics will be discussed. (author)

  18. Study on improvement of the lifetime of a field-reversed configuration by tangential neutron beam injection

    International Nuclear Information System (INIS)

    Takahashi, Toshiki; Kondoh, Yoshiomi; Hirano, Yoichi; Asai, Tomohiko; Takahashi, Tsutomu; Mizuguchi, Naoki; Tomita, Yukihiro

    2006-01-01

    The numerical analysis of neutron beam injection (NBI) is carried out to keep the stationary conditions of the field-reversed configuration (FRC) plasma. The ionization process of neutron beam was reproduced by the Monte Carlo method. A confinement of 15 keV beam ion was investigated using the sharp of stormer region obtained by the position and velocity at a moment of ionization. The relation between the external magnetic field B ex [T] and radius of machine r w [m] was shown by B ex = 0.1 r w -3/4 . The power imparted to plasma was estimated by beam ion orbital calculation. The confinement coefficient of beam ion was lost by re-charge-exchange reaction with deuterium; this fact was discovered at first. In order to keep the configuration of plasma under the conditions of 0.2 T of the external magnetic field, 0.4 m of radius, and 100 eV ion temperature, about 17 MW/m NBI power is needed. (S.Y.)

  19. UCN sources at external beams of thermal neutrons. An example of PIK reactor

    International Nuclear Information System (INIS)

    Lychagin, E.V.; Mityukhlyaev, V.A.; Muzychka, A.Yu.; Nekhaev, G.V.; Nesvizhevsky, V.V.; Onegin, M.S.; Sharapov, E.I.; Strelkov, A.V.

    2016-01-01

    We consider ultracold neutron (UCN) sources based on a new method of UCN production in superfluid helium ("4He). The PIK reactor is chosen as a perspective example of application of this idea, which consists of installing "4He UCN source in the beam of thermal or cold neutrons and surrounding the source with moderator-reflector, which plays the role of cold neutron (CN) source feeding the UCN source. CN flux in the source can be several times larger than the incident flux, due to multiple neutron reflections from the moderator–reflector. We show that such a source at the PIK reactor would provide an order of magnitude larger density and production rate than an analogous source at the ILL reactor. We estimate parameters of "4He source with solid methane (CH_4) or/and liquid deuterium (D_2) moderator–reflector. We show that such a source with CH_4 moderator–reflector at the PIK reactor would provide the UCN density of ~1·10"5 cm"−"3, and the UCN production rate of ~2·10"7 s"−"1. These values are respectively 1000 and 20 times larger than those for the most intense UCN user source. The UCN density in a source with D_2 moderator-reflector would reach the value of ~2·10"5 cm"−"3, and the UCN production rate would be equal ~8·10"7 s"−"1. Installation of such a source in a beam of CNs would slightly increase the density and production rate.

  20. Neutron beam imaging with GEM detectors

    International Nuclear Information System (INIS)

    Albani, G.; Cazzaniga, C.; Rebai, M.; Gorini, G.; Croci, G.; Muraro, A.; Cippo, E. Perelli; Tardocchi, M.; Cavenago, M.; Murtas, F.; Claps, G.; Pasqualotto, R.

    2015-01-01

    Neutron GEM-based detectors represent a new frontier of devices in neutron physics applications where a very high neutron flux must be measured such as future fusion experiments (e.g. ITER Neutral beam Injector) and spallation sources (e.g. the European Spallation source). This kind of detectors can be properly adapted to be used both as beam monitors but also as neutron diffraction detectors that could represent a valid alternative for the 3 He detectors replacement. Fast neutron GEM detectors (nGEM) feature a cathode composed by one layer of polyethylene and one of aluminium (neutron scattering on hydrogen generates protons that are detected in the gas) while thermal neutron GEM detectors (bGEM) are equipped with a borated aluminium cathode (charged particles are generated through the 10 B(n,α) 7 Li reaction). GEM detectors can be realized in large area (1 m 2 ) and their readout can be pixelated. Three different prototypes of nGEM and one prototype of bGEM detectors of different areas and equipped with different types of readout have been built and tested. All the detectors have been used to measure the fast and thermal neutron 2D beam image at the ISIS-VESUVIO beamline. The different kinds of readout patterns (different areas of the pixels) have been compared in similar conditions. All the detectors measured a width of the beam profile consitent with the expected one. The imaging property of each detector was then tested by inserting samples of different material and shape in the beam. All the samples were correctly reconstructed and the definition of the reconstruction depends on the type of readout anode. The fast neutron beam profile reconstruction was then compared to the one obtained by diamond detectors positioned on the same beamline while the thermal neutron one was compared to the imaged obtained by cadmium-coupled x-rays films. Also efficiency and the gamma background rejection have been determined. These prototypes represent the first step towards

  1. Neutron beam design for low intensity neutron and gamma-ray radioscopy using small neutron sources

    CERN Document Server

    Matsumoto, T

    2003-01-01

    Two small neutron sources of sup 2 sup 5 sup 2 Cf and sup 2 sup 4 sup 1 Am-Be radioisotopes were used for design of neutron beams applicable to low intensity neutron and gamma ray radioscopy (LINGR). In the design, Monte Carlo code (MCNP) was employed to generate neutron and gamma ray beams suited to LINGR. With a view to variable neutron spectrum and neutron intensity, various arrangements were first examined, and neutron-filter, gamma-ray shield and beam collimator were verified. Monte Carlo calculations indicated that with a suitable filter-shield-collimator arrangement, thermal neutron beam of 3,900 ncm sup - sup 2 s sup - sup 1 with neutron/gamma ratio of 7x10 sup 7 , and 25 ncm sup - sup 2 s sup - sup 1 with very large neutron/gamma ratio, respectively, could be produced by using sup 2 sup 5 sup 2 Cf(122 mu g) and a sup 2 sup 4 sup 1 Am-Be(37GBq)radioisotopes at the irradiation port of 35 cm from the neutron sources.

  2. Neutron beams. Tracks analysis, imaging and medicine

    International Nuclear Information System (INIS)

    Pepy, G.

    2006-01-01

    Thermal neutron beams can supply informations about the arrangement of atoms and molecules and about their movement inside the matter. This article treats of the preparation of thermal neutron beams and of the applications that use their penetration and matter activation properties: 1 - thermal neutrons production; 2 - basic properties of thermal neutrons: neutrons scattering, absorbing materials, activating materials, transparent materials, preparation of a neutron beam; 3 - tracks measurement by activation: activation method, measurement of marine pollution by heavy elements, historical evolution of glass composition; 4 - neutron radiography: neutronography, neutronoscopy: viscosity measurement; 5 - cancer treatment. (J.S.)

  3. Neutron filters for producing monoenergetic neutron beams

    International Nuclear Information System (INIS)

    Harvey, J.A.; Hill, N.W.; Harvey, J.R.

    1982-01-01

    Neutron transmission measurements have been made on high-purity, highly-enriched samples of 58 Ni (99.9%), 60 Ni (99.7%), 64 Zn (97.9%) and 184 W (94.5%) to measure their neutron windows and to assess their potential usefulness for producing monoenergetic beams of intermediate energies from a reactor. Transmission measurements on the Los Alamos Sc filter (44.26 cm Sc and 1.0 cm Ti) have been made to determine the characteristics of the transmitted neutron beam and to measure the total cross section of Sc at the 2.0 keV minimum. When corrected for the Ti and impurities, a value of 0.35 +- 0.03 b was obtained for this minimum

  4. Use of neutron beams for fundamental research, applications and human capacity building: From national to regional perspectives

    International Nuclear Information System (INIS)

    Nothnagel, S.G.

    2010-01-01

    The SAFARI-1 research reactor at NECSA South Africa is currently one of the best utilized research reactors in the world. Apart from being used for materials irradiation and isotope production, there is a history of innovative utilization of neutron beam line techniques, such as neutron diffraction (strain scanning, powder and single crystal), neutron radiography/tomography, prompt gamma-ray neutron activation analysis and small angle neutron scattering both for NECSA research programs and external users. Through these applications neutron beam line diagnostics have been shown to make important contributions to a number of key research areas in South Africa. As a result these techniques are now being viewed as 'standard and essential' for an increasing number of researchers who came to appreciate the extra dimension of knowledge provided by neutron techniques. In addition neutron beam line facilities provide excellent training platforms for human capacity building in nuc lear and material related science and technology. Because of these reasons neutron beam line facilities at research reactors offer unique opportunities to build productive cross-cutting research collaborations, at national and regional levels. Some information on the role that nuclear beams can play, in the capacities mentioned, will be shared by virtue of some examples and the national, international and regional net-working potential of research reactor based neutron facilities shall be discussed.

  5. Beam shaping assembly of a D-T neutron source for BNCT and its dosimetry simulation in deeply-seated tumor

    Science.gov (United States)

    Faghihi, F.; Khalili, S.

    2013-08-01

    This article involves two aims for BNCT. First case includes a beam shaping assembly estimation for a D-T neutron source to find epi-thermal neutrons which are the goal in the BNCT. Second issue is the percent depth dose calculation in the adult Snyder head phantom. Monte-Carlo simulations and verification of a suggested beam shaping assembly (including internal neutron multiplier, moderator, filter, external neutron multiplier, collimator, and reflector dimensions) for thermalizing a D-T neutron source as well as increasing neutron flux are carried out and our results are given herein. Finally, we have simulated its corresponding doses for treatment planning of a deeply-seated tumor.

  6. Accelerator Based Neutron Beams for Neutron Capture Therapy

    International Nuclear Information System (INIS)

    Yanch, Jacquelyn C.

    2003-01-01

    The DOE-funded accelerator BNCT program at the Massachusetts Institute of Technology has resulted in the only operating accelerator-based epithermal neutron beam facility capable of generating significant dose rates in the world. With five separate beamlines and two different epithermal neutron beam assemblies installed, we are currently capable of treating patients with rheumatoid arthritis in less than 15 minutes (knee joints) or 4 minutes (finger joints) or irradiating patients with shallow brain tumors to a healthy tissue dose of 12.6 Gy in 3.6 hours. The accelerator, designed by Newton scientific Incorporated, is located in dedicated laboratory space that MIT renovated specifically for this project. The Laboratory for Accelerator Beam Applications consists of an accelerator room, a control room, a shielded radiation vault, and additional laboratory space nearby. In addition to the design, construction and characterization of the tandem electrostatic accelerator, this program also resulted in other significant accomplishments. Assemblies for generating epithermal neutron beams were designed, constructed and experimentally evaluated using mixed-field dosimetry techniques. Strategies for target construction and target cooling were implemented and tested. We demonstrated that the method of submerged jet impingement using water as the coolant is capable of handling power densities of up to 6 x 10(sup 7) W/m(sup 2) with heat transfer coefficients of 10(sup 6)W/m(sup 2)-K. Experiments with the liquid metal gallium demonstrated its superiority compared with water with little effect on the neutronic properties of the epithermal beam. Monoenergetic proton beams generated using the accelerator were used to evaluate proton RBE as a function of LET and demonstrated a maximum RBE at approximately 30-40 keV/um, a finding consistent with results published by other researchers. We also developed an experimental approach to biological intercomparison of epithermal beams and

  7. Enhancing neutron beam production with a convoluted moderator

    Energy Technology Data Exchange (ETDEWEB)

    Iverson, E.B., E-mail: iversoneb@ornl.gov [Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Baxter, D.V. [Center for the Exploration of Energy and Matter, Indiana University, Bloomington, IN 47408 (United States); Muhrer, G. [Lujan Neutron Scattering Center, Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87545 (United States); Ansell, S.; Dalgliesh, R. [ISIS Facility, Rutherford Appleton Laboratory, Chilton (United Kingdom); Gallmeier, F.X. [Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Kaiser, H. [Center for the Exploration of Energy and Matter, Indiana University, Bloomington, IN 47408 (United States); Lu, W. [Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

    2014-10-21

    We describe a new concept for a neutron moderating assembly resulting in the more efficient production of slow neutron beams. The Convoluted Moderator, a heterogeneous stack of interleaved moderating material and nearly transparent single-crystal spacers, is a directionally enhanced neutron beam source, improving beam emission over an angular range comparable to the range accepted by neutron beam lines and guides. We have demonstrated gains of 50% in slow neutron intensity for a given fast neutron production rate while simultaneously reducing the wavelength-dependent emission time dispersion by 25%, both coming from a geometric effect in which the neutron beam lines view a large surface area of moderating material in a relatively small volume. Additionally, we have confirmed a Bragg-enhancement effect arising from coherent scattering within the single-crystal spacers. We have not observed hypothesized refractive effects leading to additional gains at long wavelength. In addition to confirmation of the validity of the Convoluted Moderator concept, our measurements provide a series of benchmark experiments suitable for developing simulation and analysis techniques for practical optimization and eventual implementation at slow neutron source facilities.

  8. The Thermal Neutron Beam Option for NECTAR at MLZ

    Science.gov (United States)

    Mühlbauer, M. J.; Bücherl, T.; Genreith, C.; Knapp, M.; Schulz, M.; Söllradl, S.; Wagner, F. M.; Ehrenberg, H.

    The beam port SR10 at the neutron source FRM II of Heinz Maier-Leibnitz Zentrum (MLZ) is equipped with a moveable assembly of two uranium plates, which can be placed in front of the entrance window of the beam tube via remote control. With these plates placed in their operating position the thermal neutron spectrum produced by the neutron source FRM II is converted to fission neutrons with 1.9 MeV of mean energy. This fission neutron spectrum is routinely used for medical applications at the irradiation facility MEDAPP, for neutron radiography and tomography experiments at the facility NECTAR and for materials testing. If, however, the uranium plates are in their stand-by position far off the tip of the beam tube and the so-called permanent filter for thermal neutrons is removed, thermal neutrons originating from the moderator tank enter the beam tube and a thermal spectrum becomes available for irradiation or activation of samples. By installing a temporary flight tube the beam may be used for thermal neutron radiography and tomography experiments at NECTAR. The thermal neutron beam option not only adds a pure thermal neutron spectrum to the energy ranges available for neutron imaging at MLZ instruments but it also is an unique possibility to combine two quite different neutron energy ranges at a single instrument including their respective advantages. The thermal neutron beam option for NECTAR is funded by BMBF in frame of research project 05K16VK3.

  9. Reactor-moderated intermediate-energy neutron beams for neutron-capture therapy

    International Nuclear Information System (INIS)

    Less, T.J.

    1987-01-01

    One approach to producing an intermediate energy beam is moderating fission neutrons escaping from a reactor core. The objective of this research is to evaluate materials that might produce an intermediate beam for NCT via moderation of fission neutrons. A second objective is to use the more promising moderator material in a preliminary design of an NCT facility at a research reactor. The evaluations showed that several materials or combinations of materials could produce a moderator source for an intermediate beam for NCT. The best neutron spectrum for use in NCT is produced by Al 2 O 3 , but mixtures of Al metal and D 2 O are also attractive. Using the best moderator materials, results were applied to the design of an NCT moderator at the Georgia Institute of Technology Research Reactor's bio-medical facility. The amount of photon shielding and thermal neutron absorber were optimized with respect to the desired photon dose rate and intermediate neutron flux at the patient position

  10. Neutron beam facilities at the Australian Replacement Research Reactor

    International Nuclear Information System (INIS)

    Kennedy, Shane; Robinson, Robert; Hunter, Brett

    2001-01-01

    Australia is building a research reactor to replace the HIFAR reactor at Lucas Heights by the end of 2005. Like HIFAR, the Replacement Research Reactor will be multipurpose with capabilities for both neutron beam research and radioisotope production. It will be a pool-type reactor with thermal neutron flux (unperturbed) of 4 x 10 14 n/cm 2 /sec and a liquid D 2 cold neutron source. Cold and thermal neutron beams for neutron beam research will be provided at the reactor face and in a large neutron guide hall. Supermirror neutron guides will transport cold and thermal neutrons to the guide hall. The reactor and the associated infrastructure, with the exception of the neutron beam instruments, is to be built by INVAP S.E. under contract. The neutron beam instruments will be developed by ANSTO, in consultation with the Australian user community. This status report includes a review the planned scientific capabilities, a description of the facility and a summary of progress to date. (author)

  11. Neutron capture therapy beams at the MIT Research Reactor

    International Nuclear Information System (INIS)

    Choi, J.R.; Clement, S.D.; Harling, O.K.; Zamenhof, R.G.

    1990-01-01

    Several neutron beams that could be used for neutron capture therapy at MITR-II are dosimetrically characterized and their suitability for the treatment of glioblastoma multiforme and other types of tumors are described. The types of neutron beams studied are: (1) those filtered by various thicknesses of cadmium, D2O, 6Li, and bismuth; and (2) epithermal beams achieved by filtration with aluminum, sulfur, cadmium, 6Li, and bismuth. Measured dose vs. depth data are presented in polyethylene phantom with references to what can be expected in brain. The results indicate that both types of neutron beams are useful for neutron capture therapy. The first type of neutron beams have good therapeutic advantage depths (approximately 5 cm) and excellent in-phantom ratios of therapeutic dose to background dose. Such beams would be useful for treating tumors located at relatively shallow depths in the brain. On the other hand, the second type of neutron beams have superior therapeutic advantage depths (greater than 6 cm) and good in-phantom therapeutic advantage ratios. Such beams, when used along with bilateral irradiation schemes, would be able to treat tumors at any depth in the brain. Numerical examples of what could be achieved with these beams, using RBEs, fractionated-dose delivery, unilateral, and bilateral irradiation are presented in the paper. Finally, additional plans for further neutron beam development at MITR-II are discussed

  12. Narrow beam neutron dosimetry.

    Science.gov (United States)

    Ferenci, M Sutton

    2004-01-01

    Organ and effective doses have been estimated for male and female anthropomorphic mathematical models exposed to monoenergetic narrow beams of neutrons with energies from 10(-11) to 1000 MeV. Calculations were performed for anterior-posterior, posterior-anterior, left-lateral and right-lateral irradiation geometries. The beam diameter used in the calculations was 7.62 cm and the phantoms were irradiated at a height of 1 m above the ground. This geometry was chosen to simulate an accidental scenario (a worker walking through the beam) at Flight Path 30 Left (FP30L) of the Weapons Neutron Research (WNR) Facility at Los Alamos National Laboratory. The calculations were carried out using the Monte Carlo transport code MCNPX 2.5c.

  13. Properties of the TRIUMF neutron beam

    International Nuclear Information System (INIS)

    Gan, L.; Berdoz, A.R.; Green, P.W.; Greeniaus, L.G.; Helmer, R.; Korkmaz, E.; Lee, L.; Miller, C.A.; Opper, A.K.; Page, S.A.; Van Oers, W.T.H.; Zhao, J.

    1995-01-01

    Properties of the TRIUMF neutron beam (4A/2) are presented and compared with a Monte Carlo prediction. The beam intensity profile, energy spectrum and polarization are predicted taking into account the beamline geometry, energy losses in the LD 2 production target, the properties of the vector pd→ vector npp reaction, and the scattering of neutrons from the collimator walls. The results allow for improved corrections to systematic errors in a number of TRIUMF neutron experiments. (orig.)

  14. Neutron measurements from beam-target reactions at the ELISE neutral beam test facility

    International Nuclear Information System (INIS)

    Xufei, X.; Fan, T.; Nocente, M.; Gorini, G.; Bonomo, F.; Franzen, P.; Fröschle, M.; Grosso, G.; Tardocchi, M.; Grünauer, F.; Pasqualotto, R.

    2014-01-01

    Measurements of 2.5 MeV neutron emission from beam-target reactions performed at the ELISE neutral beam test facility are presented in this paper. The measurements are used to study the penetration of a deuterium beam in a copper dump, based on the observation of the time evolution of the neutron counting rate from beam-target reactions with a liquid scintillation detector. A calculation based on a local mixing model of deuterium deposition in the target up to a concentration of 20% at saturation is used to evaluate the expected neutron yield for comparison with data. The results are of relevance to understand neutron emission associated to beam penetration in a solid target, with applications to diagnostic systems for the SPIDER and MITICA Neutral Beam Injection prototypes

  15. Scatterings and reactions by means of polarized neutron beam

    International Nuclear Information System (INIS)

    Koori, N.

    1989-01-01

    A high resolution polarized neutron beam should be prepared for nuclear physics, which will be planned with the new ring cyclotron at RCNP. Studies on scatterings and reactions by means of polarized neutron beams are reviewed briefly. Beam lines for polarized neutrons are summarized. An example of high resolution measurements of neutron induced reactions is described. (author)

  16. Polarizing beam-splitter device at a pulsed neutron source

    International Nuclear Information System (INIS)

    Itoh, Shinichi; Takeda, Masayasu.

    1996-01-01

    A polarizing beam-splitter device was designed using Fe/Si supermirrors in order to obtain two polarized neutron beam lines, from one unpolarized neutron beam line, with a practical beam size for investigating the properties of condensed matter. This device was mounted after a guide tube at a pulsed neutron source, and its performance was investigated. (author)

  17. Materials research with neutron beams from a research reactor

    Energy Technology Data Exchange (ETDEWEB)

    Root, J.; Banks, D. [Canadian Neutron Beam Centre, Chalk River Laboratories, Chalk River, Ontario (Canada)

    2015-03-15

    Because of the unique ways that neutrons interact with matter, neutron beams from a research reactor can reveal knowledge about materials that cannot be obtained as easily with other scientific methods. Neutron beams are suitable for imaging methods (radiography or tomography), for scattering methods (diffraction, spectroscopy, and reflectometry) and for other possibilities. Neutron-beam methods are applied by students and researchers from academia, industry and government to support their materials research programs in several disciplines: physics, chemistry, materials science and life science. The arising knowledge about materials has been applied to advance technologies that appear in everyday life: transportation, communication, energy, environment and health. This paper illustrates the broad spectrum of materials research with neutron beams, by presenting examples from the Canadian Neutron Beam Centre at the NRU research reactor in Chalk River. (author)

  18. Construction of the Neutron Beam Facility at Australia's OPAL Research Reactor

    International Nuclear Information System (INIS)

    Kennedy, J.S.

    2005-01-01

    Full text: Australia's new research reactor, OPAL, has been designed for high quality neutron beam science and radioisotope production. It has a capacity for eighteen neutron beam instruments to be located at the reactor face and in a neutron guide hall. The new neutron beam facility features a 20 litre liquid deuterium cold neutron source and supermirror neutron reflecting guides for intense cold and thermal neutron beams. Nine neutron beam instruments are under development, of which seven are scheduled for completion in early 2007. The project is approaching the hot-commissioning stage, where criticality will be demonstrated. Installation of the neutron beam transport system and neutron beam instruments in the neutron guide hall and at the reactor face is underway, and the path to completion of this project is relatively clear. The lecture will outline Australia's aspirations for neutron science at the OPAL reactor, and describe the neutron beam facility under construction. The status of this project and a forecast of the program to completion, including commissioning and commencement of routine operation in 2007 will also be discussed. This project is the culmination of almost a decade of effort. We now eagerly anticipate catapulting Australia's neutron beam science capability to meet the best in the world today. (author)

  19. Utilizations of filtered neutron beams at Dalat nuclear research reactor

    International Nuclear Information System (INIS)

    Hien, P.D.; Chau, L.N.; Tan, V.H.; Hiep, N.T.; Phuong, L.B.

    1992-01-01

    Neutron beam utilizations in basic and applied researches have been important activities at the Dalat nuclear reactor. The neutron filters with single crystal of silicon are used to produce thermal neutrons at the tangential horizontal channel and quasi-monoenergetic 144 KeV and 54 KeV neutrons at the piercing beam tube. The paper presents some relevant characteristics of the filtered neutron beams at the two horizontal channels. Applications of neutron beams in prompt gamma-ray activation analysis and in nuclear data measurements are briefly described. (author)

  20. External Beam Radiation Therapy for Cancer

    Science.gov (United States)

    External beam radiation therapy is used to treat many types of cancer. it is a local treatment, where a machine aims radiation at your cancer. Learn more about different types of external beam radiation therapy, and what to expect if you're receiving treatment.

  1. Neutron beam facilities at the Replacement Research Reactor, ANSTO

    International Nuclear Information System (INIS)

    Kim, S.

    2003-01-01

    The exciting development for Australia is the construction of a modern state-of-the-art 20-MW Replacement Research Reactor which is currently under construction to replace the aging reactor (HIFAR) at ANSTO in 2006. To cater for advanced scientific applications, the replacement reactor will provide not only thermal neutron beams but also a modern cold-neutron source moderated by liquid deuterium at approximately -250 deg C, complete with provision for installation of a hot-neutron source at a later stage. The latest 'supermirror' guides will be used to transport the neutrons to the Reactor Hall and its adjoining Neutron Guide Hall where a suite of neutron beam instruments will be installed. These new facilities will expand and enhance ANSTO's capabilities and performance in neutron beam science compared with what is possible with the existing HIFAR facilities, and will make ANSTO/Australia competitive with the best neutron facilities in the world. Eight 'leading-edge' neutron beam instruments are planned for the Replacement Research Reactor when it goes critical in 2006, followed by more instruments by 2010 and beyond. Up to 18 neutron beam instruments can be accommodated at the Replacement Research Reactor, however, it has the capacity for further expansion, including potential for a second Neutron Guide Hall. The first batch of eight instruments has been carefully selected in conjunction with a user group representing various scientific interests in Australia. A team of scientists, engineers, drafting officers and technicians has been assembled to carry out the Neutron Beam Instrument Project to successful completion. Today, most of the planned instruments have conceptual designs and are now being engineered in detail prior to construction and procurement. A suite of ancillary equipment will also be provided to enable scientific experiments at different temperatures, pressures and magnetic fields. This paper describes the Neutron Beam Instrument Project and gives

  2. Construction of the neutron beam facility at Australia's OPAL research reactor

    International Nuclear Information System (INIS)

    Kennedy, Shane J.

    2006-01-01

    Australia's new research reactor, OPAL, has been designed principally for neutron beam science and radioisotope production. It has a capacity for 18 neutron beam instruments, located at the reactor face and in a neutron guide hall. The neutron beam facility features a 20 l liquid deuterium cold neutron source and cold and thermal supermirror neutron guides. Nine neutron beam instruments are under development, of which seven are scheduled for completion in early 2007. The project is approaching the hot-commissioning stage, when criticality will be demonstrated. Installation of the neutron beam transport system and neutron beam instruments in the neutron guide hall and at the reactor face is underway, and the path to completion of this project is relatively clear. This paper will outline the key features of the OPAL reactor, and will describe the neutron beam facility in particular. The status of the construction and a forecast of the program to completion, including commissioning and commencement of routine operation in 2007 will also be discussed

  3. Double beam neutron radiography facility

    International Nuclear Information System (INIS)

    Domanus, J.C.

    1977-09-01

    The DR1 reactor at Risoe is used as a neutron source for neutron radiography. In the double-beam neutron radiography facility a neutron flux of an intensity of 1.4 and 1.8 x 10 6 n. cm -2 . s -1 reaches the object to be radiographed. The transport and exposure container used for neutron radiography of irradiated nuclear fuel rods is described, and the exposure technique and procedure are reviewed. The mode by which single neutron radiographs are assembled and assessed is described. This report will be published in the ''Neutron Radiography Newsletter''. (author)

  4. Subcriticality calculation in nuclear reactors with external neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Adilson Costa da; Martinez, Aquilino Senra; Silva, Fernando Carvalho da [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE). Programa de Engenharia Nuclear]. E-mails: asilva@con.ufrj.br; aquilino@lmp.ufrj.br; fernando@con.ufrj.br

    2007-07-01

    The main objective of this paper consists on the development of a methodology to monitor subcriticality. We used the inverse point kinetic equation with 6 precursor groups and external neutron sources for the calculation of reactivity. The input data for the inverse point kinetic equation was adjusted, in order to use the neutron counting rates obtained from the subcritical multiplication (1/M) in a nuclear reactor. In this paper, we assumed that the external neutron sources strength is constant and we define it in terms of a known initial condition. The results obtained from inverse point kinetic equation with external neutron sources were compared with the results obtained with a benchmark calculation, and showed good accuracy (author)

  5. Subcriticality calculation in nuclear reactors with external neutron sources

    International Nuclear Information System (INIS)

    Silva, Adilson Costa da; Martinez, Aquilino Senra; Silva, Fernando Carvalho da

    2007-01-01

    The main objective of this paper consists on the development of a methodology to monitor subcriticality. We used the inverse point kinetic equation with 6 precursor groups and external neutron sources for the calculation of reactivity. The input data for the inverse point kinetic equation was adjusted, in order to use the neutron counting rates obtained from the subcritical multiplication (1/M) in a nuclear reactor. In this paper, we assumed that the external neutron sources strength is constant and we define it in terms of a known initial condition. The results obtained from inverse point kinetic equation with external neutron sources were compared with the results obtained with a benchmark calculation, and showed good accuracy (author)

  6. Beam profiles for fast neutrons; and reply

    International Nuclear Information System (INIS)

    Bewley, D.K.; Parnell, C.J.; Bloch, P.

    1976-01-01

    The authors express surprise that Bloch et al. (Bloch, P.H., Hendry, G.O., Hilton, J.L., Quam, W.M., Reinhard, D.K., and Wilson, C., 1976, Phys. Med. Biol., Vol. 21, 450) justified a target size of 5.5 x 5.5 cm in a neutron generator by comparison with the profile given by a 2.5 MV X-ray generator. The penumbral width of this new neutron generator is more than twice that of a modern megavoltage X-ray machine, and larger than those of beams from standard 60 Co units, or of the Hammersmith Hospital cyclotron beam. The large target size of the neutron generator may have to be accepted as a necessary evil, but should not be considered satisfactory. In reply, one of the authors of the original note presents the results of calculations of beam profiles for 14 MeV neutron beams in a tissue-equivalent phantom, and suggests that the broader profiles are principally caused by the larger probability of side scatter, not by source size. The most fruitful approach to sharpening the neutron beam profile would seem to be to design a field flattening filter to increase relative dose near the edge inside the geometrically defined field. Calculations indicating that Bewley and Parnell have underestimated the penumbral widths of 60 Co beams are also presented. (U.K.)

  7. Thai Research Reactor (TRR-1/M1) Neutron Beam Measurements

    International Nuclear Information System (INIS)

    Ratanatongchai, Wichian

    2009-07-01

    Full text: Neutron beam tube of neutron radiography facility at Thai Research Reactor (TRR-1/M1) Thailand Institute of Nuclear Technology (public organization) is a divergent beam. The rectangular open-end of the beam tube is 16 cm x 17 cm while the inner-end is closed to the reactor core. The neutron beam size was measured using 20 cm x 40 cm neutron imaging plate. The measurement at the position 100 cm from the end of the collimator has shown that the beam size was 18.2 cm x 19.0 cm. Gamma ray in neutron the beam was also measured by the identical position using industrial X ray film. The area of gamma ray was 27.8 cm x 31.1 cm with the highest intensity found to be along the neutron beam circumference

  8. Effects of neutron spectrum and external neutron source on neutron multiplication parameters in accelerator-driven system

    International Nuclear Information System (INIS)

    Shahbunder, Hesham; Pyeon, Cheol Ho; Misawa, Tsuyoshi; Lim, Jae-Yong; Shiroya, Seiji

    2010-01-01

    The neutron multiplication parameters: neutron multiplication M, subcritical multiplication factor k s , external source efficiency φ*, play an important role for numerical assessment and reactor power evaluation of an accelerator-driven system (ADS). Those parameters can be evaluated by using the measured reaction rate distribution in the subcritical system. In this study, the experimental verification of this methodology is performed in various ADS cores; with high-energy (100 MeV) proton-tungsten source in hard and soft neutron spectra cores and 14 MeV D-T neutron source in soft spectrum core. The comparison between measured and calculated multiplication parameters reveals a maximum relative difference in the range of 6.6-13.7% that is attributed to the calculation nuclear libraries uncertainty and accuracy for energies higher than 20 MeV and also dependent on the reaction rate distribution position and count rates. The effects of different core neutron spectra and external neutron sources on the neutron multiplication parameters are discussed.

  9. Filtered epithermal quasi-monoenergetic neutron beams at research reactor facilities

    International Nuclear Information System (INIS)

    Mansy, M.S.; Bashter, I.I.; El-Mesiry, M.S.; Habib, N.; Adib, M.

    2015-01-01

    Filtered neutron techniques were applied to produce quasi-monoenergetic neutron beams in the energy range of 1.5–133 keV at research reactors. A simulation study was performed to characterize the filter components and transmitted beam lines. The filtered beams were characterized in terms of the optimal thickness of the main and additive components. The filtered neutron beams had high purity and intensity, with low contamination from the accompanying thermal emission, fast neutrons and γ-rays. A computer code named “QMNB” was developed in the “MATLAB” programming language to perform the required calculations. - Highlights: • Quasi-monoenergetic neutron beams in energy range from (1.5–133) keV. • Interference between the resonance and potential scattering amplitudes. • Epithermal neutron beams used in BNCT

  10. Triple GEM gas detectors as real time fast neutron beam monitors for spallation neutron sources

    International Nuclear Information System (INIS)

    Murtas, F; Claps, G; Croci, G; Tardocchi, M; Pietropaolo, A; Cippo, E Perelli; Rebai, M; Gorini, G; Frost, C D; Raspino, D; Rhodes, N J; Schooneveld, E M

    2012-01-01

    A fast neutron beam monitor based on a triple Gas Electron Multiplier (GEM) detector was developed and tested for the ISIS spallation neutron source in U.K. The test on beam was performed at the VESUVIO beam line operating at ISIS. The 2D fast neutron beam footprint was recorded in real time with a spatial resolution of a few millimeters thanks to the patterned detector readout.

  11. Beam Characterization at the Neutron Radiography Facility

    Energy Technology Data Exchange (ETDEWEB)

    Sarah Morgan; Jeffrey King

    2013-01-01

    The quality of a neutron imaging beam directly impacts the quality of radiographic images produced using that beam. Fully characterizing a neutron beam, including determination of the beam’s effective length-to-diameter ratio, neutron flux profile, energy spectrum, image quality, and beam divergence, is vital for producing quality radiographic images. This project characterized the east neutron imaging beamline at the Idaho National Laboratory Neutron Radiography Reactor (NRAD). The experiments which measured the beam’s effective length-to-diameter ratio and image quality are based on American Society for Testing and Materials (ASTM) standards. An analysis of the image produced by a calibrated phantom measured the beam divergence. The energy spectrum measurements consist of a series of foil irradiations using a selection of activation foils, compared to the results produced by a Monte Carlo n-Particle (MCNP) model of the beamline. Improvement of the existing NRAD MCNP beamline model includes validation of the model’s energy spectrum and the development of enhanced image simulation methods. The image simulation methods predict the radiographic image of an object based on the foil reaction rate data obtained by placing a model of the object in front of the image plane in an MCNP beamline model.

  12. Activation analysis opportunities using cold neutron beams

    Energy Technology Data Exchange (ETDEWEB)

    Lindstrom, R M; Zeisler, R; Rossbach, M

    1987-05-01

    Guided beams of cold neutrons being installed at a number of research reactors may become increasingly available for analytical research. A guided cold beam will provide higher neutron fluence rates and lower background interferences than in present facilities. In an optimized facility, fluence rates of 10/sup 9/ nxcm/sup -2/xs/sup -1/ are obtainable. Focusing a large area beam onto a small target will further increase the neutron intensity. In addition, the shift to lower neutron energy increases the effective cross sections. The absence of fast neutrons and gamma rays permits detectors to be placed near the sample without intolerable background, and thus the efficiency for counting prompt gamma rays can be much higher than in present systems. Measurements made at the hydrogen cold source of the FRJ-2 (DIDO) reactor at the KFA provide a numerical evaluation of the improvements in PGAA with respect to signal-to-background ratios of important elements and matrices. (author) 15 refs.

  13. Intermediate-energy neutron beams from reactors for NCT

    International Nuclear Information System (INIS)

    Brugger, R.M.; Less, T.J.; Passmore, G.G.

    1986-01-01

    This paper discusses ways that a beam of intermediate-energy neutrons might be extracted from a nuclear reactor. The challenge is to suppress the fast-neutron component and the gamma-ray component of the flux while leaving enough of the intermediate-energy neutrons in the beam to be able to perform neutron capture therapy in less than an hour exposure time. Moderators, filters, and reflectors are considered. 11 references, 7 figures, 3 tables

  14. The neutron beam facility at the Australian replacement research reactor

    International Nuclear Information System (INIS)

    Hunter, B.; Kennedy, S.

    1999-01-01

    Full text: The Australian federal government gave ANSTO final approval to build a research reactor to replace HIFAR on August 25th 1999. The replacement reactor is to be a multipurpose reactor with a thermal neutron flux of 3 x 10 14 n.cm -2 .s -1 and having improved capabilities for neutron beam research and for the production of radioisotopes for pharmaceutical, scientific and industrial use. The replacement reactor will commence operation in 2005 and will cater for Australian scientific, industrial and medical needs well into the 21st century. The scientific capabilities of the neutron beams at the replacement reactor are being developed in consultation with representatives from academia, industry and government research laboratories to provide a facility for condensed matter research in physics, chemistry, materials science, life sciences, engineering and earth sciences. Cold, thermal and hot neutron sources are to be installed, and neutron guides will be used to position most of the neutron beam instruments in a neutron guide hall outside the reactor confinement building. Eight instruments are planned for 2005, with a further three to be developed by 2010. A conceptual layout for the neutron beam facility is presented including the location of the planned suite of neutron beam instruments. The reactor and all the associated infrastructure, with the exception of the neutron beam instruments, is to be built by an accredited reactor builder in a turnkey contract. Tenders have been called for December 1999, with selection of contractor planned by June 2000. The neutron beam instruments will be developed by ANSTO and other contracted organisations in consultation with the user community and interested overseas scientists. The facility will be based, as far as possible, around a neutron guide hall that is be served by three thermal and three cold neutron guides. Efficient transportation of thermal and cold neutrons to the guide hall requires the use of modern super

  15. Numerical study of neutron beam divergence in a beam-fusion scenario employing laser driven ions

    Science.gov (United States)

    Alejo, A.; Green, A.; Ahmed, H.; Robinson, A. P. L.; Cerchez, M.; Clarke, R.; Doria, D.; Dorkings, S.; Fernandez, J.; McKenna, P.; Mirfayzi, S. R.; Naughton, K.; Neely, D.; Norreys, P.; Peth, C.; Powell, H.; Ruiz, J. A.; Swain, J.; Willi, O.; Borghesi, M.; Kar, S.

    2016-09-01

    The most established route to create a laser-based neutron source is by employing laser accelerated, low atomic-number ions in fusion reactions. In addition to the high reaction cross-sections at moderate energies of the projectile ions, the anisotropy in neutron emission is another important feature of beam-fusion reactions. Using a simple numerical model based on neutron generation in a pitcher-catcher scenario, anisotropy in neutron emission was studied for the deuterium-deuterium fusion reaction. Simulation results are consistent with the narrow-divergence (∼ 70 ° full width at half maximum) neutron beam recently served in an experiment employing multi-MeV deuteron beams of narrow divergence (up to 30° FWHM, depending on the ion energy) accelerated by a sub-petawatt laser pulse from thin deuterated plastic foils via the Target Normal Sheath Acceleration mechanism. By varying the input ion beam parameters, simulations show that a further improvement in the neutron beam directionality (i.e. reduction in the beam divergence) can be obtained by increasing the projectile ion beam temperature and cut-off energy, as expected from interactions employing higher power lasers at upcoming facilities.

  16. Design, construction and characterization of a new neutron beam for neutron radiography at the Tehran Research Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Choopan Dastjerdi, M.H., E-mail: mdastjerdi@aeoi.org.ir [Reactor Research School, Nuclear Science and Technology Research Institute, Atomic Energy Organization of Iran, Tehran (Iran, Islamic Republic of); Department of Energy Engineering and Physics, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Khalafi, H.; Kasesaz, Y.; Mirvakili, S.M.; Emami, J.; Ghods, H.; Ezzati, A. [Reactor Research School, Nuclear Science and Technology Research Institute, Atomic Energy Organization of Iran, Tehran (Iran, Islamic Republic of)

    2016-05-11

    To obtain a thermal neutron beam for neutron radiography applications, a neutron collimator has been designed and implemented at the Tehran Research Reactor (TRR). TRR is a 5 MW open pool light water moderated reactor with seven beam tubes. The neutron collimator is implemented in the E beam tube of the TRR. The design of the neutron collimator was performed using MCNPX Monte Carlo code. In this work, polycrystalline bismuth and graphite have been used as a gamma filter and an illuminator, respectively. The L/D parameter of the facility was chosen in the range of 150–250. The thermal neutron flux at the image plane can be varied from 2.26×10{sup 6} to 6.5×10{sup 6} n cm{sup −2} s{sup −1}. Characterization of the beam was performed by ASTM standard IQI and foil activation technique to determine the quality of neutron beam. The results show that the obtained neutron beam has a good quality for neutron radiography applications.

  17. Design of filtered epithermal neutron beams for BNC

    International Nuclear Information System (INIS)

    Greenwood, R.C.

    1986-01-01

    The design principles of filters (installed in nuclear reactors) to provide epithermal neutron beams suitable for use in 10 B Neutron Capture Therapy (BNCT) are reviewed. The goal of such filters is to provide epithermal neutron beams within an energy range of 1 keV to 30 keV with fluxes in excess of 5 x 10 8 neutrons/cm 2 .s, and having acceptably low contaminant fast neutron (> 30 keV) and gamma components. Filters considered for this application include 238 U, Sc, Fe/Al and Al/S. It is shown that in order to achieve a goal epithermal neutron flux of > 5 x 10 8 neutrons/cm 2 .s, such filters must be located in radial beam channels which view essentially the complete reactor core. Based on considerations of estimated epithermal fluxes, cost and availability of materials, and transmitted neutron energy spectrum, it is suggested that a filter consisting of elements of Al, S, Ti and V might prove to be an optimum design for BNCT applications. 13 references, 3 figures, 8 tables

  18. Evaluation of the Induced Activity in Air by the External Proton Beam in the Target Room of the Proton Accelerator Facility of Proton Engineering Frontier Project

    International Nuclear Information System (INIS)

    Lee, Cheol Woo; Lee, Young Ouk; Cho, Young Sik; Ahn, So Hyun

    2007-01-01

    One of the radiological concerns is the worker's exposure level and the concentration of the radionuclides in the air after shutdown, for the safety analysis on the proton accelerator facility. Although, the primary radiation source is the protons accelerated up to design value, all of the radio-nuclide is produced from the secondary neutron and photon induced reaction in air. Because, the protons don't penetrate the acceleration equipment like the DTL tank wall or BTL wall, secondary neutrons or photons are only in the air in the accelerator tunnel building because of the short range of the proton in the materials. But, for the case of the target rooms, external proton beams are occasionally used in the various experiments. When these external proton beams travel through air from the end of the beam transport line to the target, they interact directly with air and produce activation products from the proton induced reaction. The external proton beam will be used in the target rooms in the accelerator facility of the Proton Accelerator Frontier Project (PEFP). In this study, interaction characteristics of the external proton beam with air and induced activity in air from the direct interaction of the proton beam were evaluated

  19. Beam-beam effects under the influence of external noise

    International Nuclear Information System (INIS)

    Ohmi, K

    2014-01-01

    Fast external noise, which gives fluctuation into the beam orbit, is discussed in connection with beam-beam effects. Phase noise from crab cavities and detection devices (position monitor) and kicker noise from the bunch by bunch feedback system are the sources. Beam-beam collisions with fast orbit fluctuations with turn by turn or multi-turn correlations, cause emittance growth and luminosity degradation. We discuss the tolerance of the noise amplitude for LHC and HL-LHC

  20. Monte Carlo program for the cold neutron beam guide

    International Nuclear Information System (INIS)

    Yoshiki, H.

    1985-02-01

    A Monte Carlo program for the transport of cold neutrons through beam guides has been developed assuming that the neutrons follow the specular reflections. Cold neutron beam guides are normally used to transport cold neutrons (4 ∼ 10 Angstrom) to experimental equipments such as small angle scattering apparatus, TOF measuring devices, polarized neutron spectrometers, and ultra cold neutron generators, etc. The beam guide is about tens of meters in length and is composed from a meter long guide elements made up from four pieces of Ni coated rectangular optical glass. This report describes mathematics and algorithm employed in the Monte Carlo program together with the display of the results. The source program and input data listings are also attached. (Aoki, K.)

  1. Modification of NUR II neutron beam profile of MINT TRIGA MARK II research reactor for digital neutron radiography

    International Nuclear Information System (INIS)

    Muhammad Rawi Mohamed Zin; Azali Muhammad; Abdul Aziz Mohamed; Rafhayudi Jamro; Syed Nasaruddin Syed Idris; Ng Aik Hao; Rosly Jaafar

    2006-01-01

    A cone neutron beam collimated by a 5.4 cm aperture produced in the Neutron Radiography II (NUR II) via a step divergence collimator had to be modified to fulfill 5 cm x 6 cm dimension of the scintillation screen placed in the charge couple device (ccd) camera. The required convergence neutron beam was obtained by a simple collimator-beam plug plugged in front of the NUR II beam port. The calculations involved in designing the collimator-beam plug had to take into account not only the neutron beam profiling but also the neutron and gamma shielding and are discussed in this article. (Author)

  2. nGEM fast neutron detectors for beam diagnostics

    International Nuclear Information System (INIS)

    Croci, G.; Claps, G.; Cavenago, M.; Dalla Palma, M.; Grosso, G.; Murtas, F.; Pasqualotto, R.; Perelli Cippo, E.; Pietropaolo, A.; Rebai, M.; Tardocchi, M.; Tollin, M.; Gorini, G.

    2013-01-01

    Fast neutron detectors with a sub-millimetric space resolution are required in order to qualify neutron beams in applications related to magnetically-controlled nuclear fusion plasmas and to spallation sources. A nGEM detector has been developed for the CNESM diagnostic system of the SPIDER NBI prototype for ITER and as beam monitor for fast neutrons lines at spallation sources. The nGEM is a triple GEM gaseous detector equipped with polypropylene and polyethylene layers used to convert fast neutrons into recoil protons through the elastic scattering process. This paper describes the results obtained by testing a nGEM detector at the ISIS spallation source on the VESUVIO beam line. Beam profiles (σ x =14.35 mm, σ y =15.75 mm), nGEM counting efficiency (around 10 -4 for 3 MeV n <15 MeV), detector stability (≈4.5%) and the effect of filtering the beam with different type of materials were successfully measured. The x beam profile was compared to the one measured by a single crystal diamond detector. Finally, the efficiency of the detector was simulated exploiting the GEANT4 tool

  3. Beam shaping assembly of a D–T neutron source for BNCT and its dosimetry simulation in deeply-seated tumor

    International Nuclear Information System (INIS)

    Faghihi, F.; Khalili, S.

    2013-01-01

    This article involves two aims for BNCT. First case includes a beam shaping assembly estimation for a D–T neutron source to find epi-thermal neutrons which are the goal in the BNCT. Second issue is the percent depth dose calculation in the adult Snyder head phantom. Monte-Carlo simulations and verification of a suggested beam shaping assembly (including internal neutron multiplier, moderator, filter, external neutron multiplier, collimator, and reflector dimensions) for thermalizing a D–T neutron source as well as increasing neutron flux are carried out and our results are given herein. Finally, we have simulated its corresponding doses for treatment planning of a deeply-seated tumor. - Highlights: ► An assembly for the D–T neutron source including many regions is given herein. ► Dosimetry simulations in the Snyder head phantom for a deeply-seated tumor are carried out. ► Brief literatures conclusions on the recent BNCT studies are presented herein

  4. Device for guiding a subthermal neutron beam and focussing device made of micro-neutron guides

    International Nuclear Information System (INIS)

    Marx, D.

    1977-01-01

    The invention concerns a device for guiding, in particular for diverting, a subthermal neutron beam with curved boundary surfaces at least in one level, whose sides towards the neutron beam are covered with at least one coating which reflects the subthermal neutrons completely. (orig./RW) [de

  5. Neutron beam applications - A development of real-time imaging processing for neutron radiography

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Whoi Yul; Lee, Sang Yup; Choi, Min Seok; Hwang, Sun Kyu; Han, Il Ho; Jang, Jae Young [Hanyang University, Seoul (Korea)

    1999-08-01

    This research is sponsored and supported by KAERI as a part of {sup A}pplication of Neutron Radiography Beam.{sup M}ain theme of the research is to develop a non-destructive inspection system for the task of studying the real-time behaviour of dynamic motion using neutron beam with the aid of a special purpose real-time image processing system that allows to capture an image of internal structure of a specimen. Currently, most off-the-shelf image processing programs designed for visible light or X-ray are not adequate for the applications that require neutron beam generated by the experimental nuclear reactor. In addition, study of dynamic motion of a specimen is severely constrained by such image processing systems. In this research, a special image processing system suited for such application is developed which not only supplements the commercial image processing system but allows to use neutron beam directly in the system for the study. 18 refs., 21 figs., 1 tab. (Author)

  6. Epithermal neutron beam interference with cardiac pacemakers

    International Nuclear Information System (INIS)

    Koivunoro, H.; Serén, T.; Hyvönen, H.; Kotiluoto, P.; Iivonen, P.; Auterinen, I.; Seppälä, T.; Kankaanranta, L.; Pakarinen, S.; Tenhunen, M.; Savolainen, S.

    2011-01-01

    In this paper, a phantom study was performed to evaluate the effect of an epithermal neutron beam irradiation on the cardiac pacemaker function. Severe malfunction occurred in the pacemakers after substantially lower dose from epithermal neutron irradiation than reported in the fast neutron or photon beams at the same dose rate level. In addition the pacemakers got activated, resulting in nuclides with half-lives from 25 min to 115 d. We suggest that BNCT should be administrated only after removal of the pacemaker from the vicinity of the tumor.

  7. Epithermal neutron beam interference with cardiac pacemakers

    Energy Technology Data Exchange (ETDEWEB)

    Koivunoro, H., E-mail: hanna.koivunoro@helsinki.fi [Department of Physics, P.O.B. 64, FI-00014 University of Helsinki (Finland)] [Department of Oncology, Helsinki University Central Hospital, P.O.B. 180, FIN-00029 HUS (Finland)] [Boneca Corporation, Finland, Filnland (Finland); Seren, T. [VTT Technical Research Centre of Finland (Finland); Hyvoenen, H. [Boneca Corporation, Finland, Filnland (Finland); Kotiluoto, P. [VTT Technical Research Centre of Finland (Finland); Iivonen, P. [St. Jude Medical (Finland); Auterinen, I. [VTT Technical Research Centre of Finland (Finland); Seppaelae, T.; Kankaanranta, L. [Department of Oncology, Helsinki University Central Hospital, P.O.B. 180, FIN-00029 HUS (Finland); Pakarinen, S. [Department of Cardiology, Helsinki University Central Hospital (Finland); Tenhunen, M. [Department of Oncology, Helsinki University Central Hospital, P.O.B. 180, FIN-00029 HUS (Finland); Savolainen, S. [HUS Helsinki Medical Imaging Center, Helsinki University Central Hospital (Finland)

    2011-12-15

    In this paper, a phantom study was performed to evaluate the effect of an epithermal neutron beam irradiation on the cardiac pacemaker function. Severe malfunction occurred in the pacemakers after substantially lower dose from epithermal neutron irradiation than reported in the fast neutron or photon beams at the same dose rate level. In addition the pacemakers got activated, resulting in nuclides with half-lives from 25 min to 115 d. We suggest that BNCT should be administrated only after removal of the pacemaker from the vicinity of the tumor.

  8. Neutron beam facilities at the replacement research reactor

    International Nuclear Information System (INIS)

    Kennedy, S.

    1999-01-01

    Full text: On September 3rd 1997 the Australian Federal Government announced their decision to replace the HIFAR research reactor by 2005. The proposed reactor will be a multipurpose reactor with improved capabilities for neutron beam research and for the production of radioisotopes for pharmaceutical, scientific and industrial use. The neutron beam facilities are intended to cater for Australian scientific needs well into the 21st century. In the first stage of planning the neutron Beam Facilities at the replacement reactor, a Consultative Group was formed (BFCG) to determine the scientific capabilities of the new facility. Members of the group were drawn from academia, industry and government research laboratories. The BFCG submitted their report in April 1998, outlining the scientific priorities to be addressed. Cold and hot neutron sources are to be included, and cold and thermal neutron guides will be used to position most of the instruments in a neutron guide hall outside the reactor confinement building. In 2005 it is planned to have eight instruments installed with a further three to be developed by 2010, and seven spare instrument positions for development of new instruments over the life of the reactor. A beam facilities technical group (BFTG) was then formed to prepare the engineering specifications for the tendering process. The group consisted of some members of the BFCG, several scientists and engineers from ANSTO, and scientists from leading neutron scattering centres in Europe, USA and Japan. The BFTG looked in detail at the key components of the facility such as the thermal, cold and hot neutron sources, neutron collimators, neutron beam guides and overall requirements for the neutron guide hall. The report of the BFTG, completed in August 1998, was incorporated into the draft specifications for the reactor project, which were distributed to potential reactor vendors. An assessment of the first stage of reactor vendor submissions was completed in

  9. Filtered epithermal quasi-monoenergetic neutron beams at research reactor facilities.

    Science.gov (United States)

    Mansy, M S; Bashter, I I; El-Mesiry, M S; Habib, N; Adib, M

    2015-03-01

    Filtered neutron techniques were applied to produce quasi-monoenergetic neutron beams in the energy range of 1.5-133keV at research reactors. A simulation study was performed to characterize the filter components and transmitted beam lines. The filtered beams were characterized in terms of the optimal thickness of the main and additive components. The filtered neutron beams had high purity and intensity, with low contamination from the accompanying thermal emission, fast neutrons and γ-rays. A computer code named "QMNB" was developed in the "MATLAB" programming language to perform the required calculations. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Prediction of the neutrons subcritical multiplication using the diffusion hybrid equation with external neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    Costa da Silva, Adilson; Carvalho da Silva, Fernando [COPPE/UFRJ, Programa de Engenharia Nuclear, Caixa Postal 68509, 21941-914, Rio de Janeiro (Brazil); Senra Martinez, Aquilino, E-mail: aquilino@lmp.ufrj.br [COPPE/UFRJ, Programa de Engenharia Nuclear, Caixa Postal 68509, 21941-914, Rio de Janeiro (Brazil)

    2011-07-15

    Highlights: > We proposed a new neutron diffusion hybrid equation with external neutron source. > A coarse mesh finite difference method for the adjoint flux and reactivity calculation was developed. > 1/M curve to predict the criticality condition is used. - Abstract: We used the neutron diffusion hybrid equation, in cartesian geometry with external neutron sources to predict the subcritical multiplication of neutrons in a pressurized water reactor, using a 1/M curve to predict the criticality condition. A Coarse Mesh Finite Difference Method was developed for the adjoint flux calculation and to obtain the reactivity values of the reactor. The results obtained were compared with benchmark values in order to validate the methodology presented in this paper.

  11. Prediction of the neutrons subcritical multiplication using the diffusion hybrid equation with external neutron sources

    International Nuclear Information System (INIS)

    Costa da Silva, Adilson; Carvalho da Silva, Fernando; Senra Martinez, Aquilino

    2011-01-01

    Highlights: → We proposed a new neutron diffusion hybrid equation with external neutron source. → A coarse mesh finite difference method for the adjoint flux and reactivity calculation was developed. → 1/M curve to predict the criticality condition is used. - Abstract: We used the neutron diffusion hybrid equation, in cartesian geometry with external neutron sources to predict the subcritical multiplication of neutrons in a pressurized water reactor, using a 1/M curve to predict the criticality condition. A Coarse Mesh Finite Difference Method was developed for the adjoint flux calculation and to obtain the reactivity values of the reactor. The results obtained were compared with benchmark values in order to validate the methodology presented in this paper.

  12. Directed Neutron Beams From Inverse Kinematic Reactions

    Science.gov (United States)

    Vanhoy, J. R.; Guardala, N. A.; Glass, G. A.

    2011-06-01

    Kinematic focusing of an emitted fairly mono-energetic neutron beam by the use of inverse-kinematic reactions, i.e. where the projectile mass is greater than the target atom's mass, can provide for the utilization of a significant fraction of the fast neutron yield and also provide for a safer radiation environment. We examine the merit of various neutron production reactions and consider the practicalities of producing the primary beam using the suitable accelerator technologies. Preliminary progress at the NSWC-Carderock Positive Ion Accelerator Facility is described. Possible important applications for this type of neutron-based system can be both advanced medical imaging techniques and active "stand-off" interrogation of contraband items.

  13. NSPEC - A neutron spectrum code for beam-heated fusion plasmas

    International Nuclear Information System (INIS)

    Scheffel, J.

    1983-06-01

    A 3-dimensional computer code is described, which computes neutron spectra due to beam heating of fusion plasmas. Three types of interactions are considered; thermonuclear of plasma-plasma, beam-plasma and beam-beam interactions. Beam deposition is modelled by the NFREYA code. The applied steady state beam distribution as a function of pitch angle and velocity contains the effects of energy diffusion, friction, angular scattering, charge exchange, electric field and source pitch angle distribution. The neutron spectra, generated by Monte-Carlo methods, are computed with respect to given lines of sight. This enables the code to be used for neutron diagnostics. (author)

  14. Boron neutron capture therapy (BNCT). Recent aspect, a change from thermal neutron to epithermal neutron beam and a new protocol

    International Nuclear Information System (INIS)

    Nakagawa, Yoshinobu

    1999-01-01

    Since 1968, One-hundred seventy three patients with glioblastoma (n=81), anaplastic astrocytoma (n=44), low grade astrocytoma (n=16) or other types of tumor (n=32) were treated by boron-neutron capture therapy (BNCT) using a combination of thermal neutron and BSH in 5 reactors (HTR n=13, JRR-3 n=1, MuITR n=98, KUR n=28, JRR-2 n=33). Out of 101 patients with glioma treated by BNCT under the recent protocol, 33 (10 glioblastoma, 14 anaplastic astrocytoma, 9 low grade astrocytoma) patients lived or have lived longer than 3 years. Nine of these 33 lived or have lived longer than 10 years. According to the retrospective analysis, the important factors related to the clinical results were tumor dose radiation dose and maximum radiation dose in thermal brain cortex. The result was not satisfied as it was expected. Then, we decided to introduce mixed beams which contain thermal neutron and epithermal neutron beams. KUR was reconstructed in 1996 and developed to be available to use mixed beams. Following the shutdown of the JRR-2, JRR-4 was renewed for medical use in 1998. Both reactors have capacity to yield thermal neutron beam, epithermal neutron beam and mixed beams. The development of the neutron source lead us to make a new protocol. (author)

  15. About possibilities of obtaining focused beams of thermal neutrons of radionuclide source

    International Nuclear Information System (INIS)

    Aripov, G.A.; Kurbanov, B.I.; Sulaymanov, N.T.; Ergashev, A.

    2004-01-01

    Full text: In the last years significant progress is achieved in development of neutron focusing methods (concentrating neutrons in a given direction and a small area). In this, main attention is given to focusing of neutron beams of reactor, particularly cold neutrons and their applications. [1,2]. However, isotope sources also let obtain intensive neutron beams and solve quite important (tasks) problems (e.g. neutron capture therapy for malignant tumors) [3], and an actual problems is focusing of neutrons. We developed a device on the basis of californium source of neutrons, allowing to obtain focused (preliminarily) beam of thermal neutrons with the aid of respective choice of moderators, reflectors and geometry of their disposition. Here, fast neutrons and gamma rays in the beam are minimized. With the aid of the model we developed on the basis of Monte-Carlo method, it is possible to modify aforementioned device and dynamics of output neutrons in wide energy range and analyze ways of optimization of neutron beams of isotope sources with different neutron outputs. Device of preliminary focusing of thermal neutrons can serve as a basis for further focus of neutrons using micro- and nano-capillar systems. It is known that, capillary systems performed with certain technology can form beam of thermal neutrons increasing its density by more than two orders of magnitude and effectively divert beams up to 20 o with length of system 15 cm

  16. About possibilities of obtaining focused beams of thermal neutrons of radionuclide source

    International Nuclear Information System (INIS)

    Aripov, G.A.; Kurbanov, B.I.; Sulaymanov, N.T.; Ergashev, A.

    2004-01-01

    In the last years significant progress is achieved in development of neutron focusing methods (concentrating neutrons in a given direction and a small area). In this, main attention is given to focusing of neutron beams of reactor, particularly cold neutrons and their applications. [1,2]. However, isotope sources also let obtain intensive neutron beams and solve quite important (tasks) problems (e.g. neutron capture therapy for malignant tumors) [3], and an actual problems is focusing of neutrons. We developed a device on the basis of californium source of neutrons, allowing to obtain focused (preliminarily) beam of thermal neutrons with the aid of respective choice of moderators, reflectors and geometry of their disposition. Here, fast neutrons and gamma rays in the beam are minimized. With the aid of the model we developed on the basis of Monte-Carlo method, it is possible to modify aforementioned device and dynamics of output neutrons in wide energy range and analyze ways of optimization of neutron beams of isotope sources with different neutron outputs. Device of preliminary focusing of thermal neutrons can serve as a basis for further focus of neutrons using micro- and nano-capillary systems. It is known that, capillary systems performed with certain technology can form beam of thermal neutrons increasing its density by more than two orders of magnitude and effectively divert beams up to 20 o with length of system 15 cm. (author)

  17. A white beam neutron spin splitter

    International Nuclear Information System (INIS)

    Krist, T.; Klose, F.; Felcher, G.P.

    1997-01-01

    The polarization of a narrow, highly collimated polychromatic neutron beam is tested by a neutron spin splitter that permits the simultaneous measurement of both spin states. The device consists of a Si-Co 0.11 Fe 0.89 supermirror, which totally reflects one spin state up to a momentum transfer q=0.04 angstrom -1 , whilst transmits neutrons of the opposite spin state. The supermirror is sandwitched between two thick silicon wafers and is magnetically saturated by a magnetic field of 400 Oe parallel to its surface. The neutron beam enters through the edge of one of the two silicon wavers, its spin components are split by the supermirror and exit from the opposite edges of the two silicon wafers and are recorded at different channels of a position-sensitive detector. The device is shown to have excellent efficiency over a broad range of wavelengths

  18. A white beam neutron spin splitter

    Energy Technology Data Exchange (ETDEWEB)

    Krist, T. [Hahn Meitner Institute, Berlin (Germany); Klose, F.; Felcher, G.P. [Argonne National Lab., IL (United States)

    1997-07-23

    The polarization of a narrow, highly collimated polychromatic neutron beam is tested by a neutron spin splitter that permits the simultaneous measurement of both spin states. The device consists of a Si-Co{sub 0.11} Fe{sub 0.89} supermirror, which totally reflects one spin state up to a momentum transfer q=0.04 {angstrom}{sup -1}, whilst transmits neutrons of the opposite spin state. The supermirror is sandwitched between two thick silicon wafers and is magnetically saturated by a magnetic field of 400 Oe parallel to its surface. The neutron beam enters through the edge of one of the two silicon wavers, its spin components are split by the supermirror and exit from the opposite edges of the two silicon wafers and are recorded at different channels of a position-sensitive detector. The device is shown to have excellent efficiency over a broad range of wavelengths.

  19. Directionally positionable neutron beam

    International Nuclear Information System (INIS)

    Dance, W.E.; Bumgardner, H.M.

    1981-01-01

    Disclosed is apparatus for forming and directionally positioning a neutron beam. The apparatus includes an enclosed housing rotatable about a first axis with a neutron source axially positioned on the axis of rotation of the enclosed housing but not rotating with the housing. The rotatable housing is carried by a vertically positionable arm carried on a mobile transport. A collimator is supported by the rotatable housing and projects into the housing to orientationally position its inlet window at an adjustably fixed axial and radial spacing from the neutron source so that rotation of the enclosed housing causes the inlet window to rotate about a circle which is a fixed axial distance from the neutron source and has the axis of rotation of the housing as its center. (author)

  20. Beam transient analyses of Accelerator Driven Subcritical Reactors based on neutron transport method

    Energy Technology Data Exchange (ETDEWEB)

    He, Mingtao; Wu, Hongchun [School of Nuclear Science and Technology, Xi’an Jiaotong University, Xi’an 710049, Shaanxi (China); Zheng, Youqi, E-mail: yqzheng@mail.xjtu.edu.cn [School of Nuclear Science and Technology, Xi’an Jiaotong University, Xi’an 710049, Shaanxi (China); Wang, Kunpeng [Nuclear and Radiation Safety Center, PO Box 8088, Beijing 100082 (China); Li, Xunzhao; Zhou, Shengcheng [School of Nuclear Science and Technology, Xi’an Jiaotong University, Xi’an 710049, Shaanxi (China)

    2015-12-15

    Highlights: • A transport-based kinetics code for Accelerator Driven Subcritical Reactors is developed. • The performance of different kinetics methods adapted to the ADSR is investigated. • The impacts of neutronic parameters deteriorating with fuel depletion are investigated. - Abstract: The Accelerator Driven Subcritical Reactor (ADSR) is almost external source dominated since there is no additional reactivity control mechanism in most designs. This paper focuses on beam-induced transients with an in-house developed dynamic analysis code. The performance of different kinetics methods adapted to the ADSR is investigated, including the point kinetics approximation and space–time kinetics methods. Then, the transient responds of beam trip and beam overpower are calculated and analyzed for an ADSR design dedicated for minor actinides transmutation. The impacts of some safety-related neutronics parameters deteriorating with fuel depletion are also investigated. The results show that the power distribution varying with burnup leads to large differences in temperature responds during transients, while the impacts of kinetic parameters and feedback coefficients are not very obvious. Classification: Core physic.

  1. Neutron emission in neutral beam heated KSTAR plasmas and its application to neutron radiography

    Energy Technology Data Exchange (ETDEWEB)

    Kwak, Jong-Gu, E-mail: jgkwak@nfri.re.kr; Kim, H.S.; Cheon, M.S.; Oh, S.T.; Lee, Y.S.; Terzolo, L.

    2016-11-01

    Highlights: • We measured the neutron emission from KSTAR plasmas quantitatively. • We confirmed that neutron emission is coming from neutral beam-plasma interactions. • The feasibility study shows that the fast neutron from KSTAR could be used for fast neutron radiography. - Abstract: The main mission of Korea Superconducting Tokamak Advanced Research (KSTAR) program is exploring the physics and technologies of high performance steady state Tokamak operation that are essential for ITER and fusion reactor. Since the successful first operation in 2008, the plasma performance is enhanced and duration of H-mode is extended to around 50 s which corresponds to a few times of current diffusion time and surpassing the current conventional Tokamak operation. In addition to long-pulse operation, the operational boundary of the H-mode discharge is further extended over MHD no-wall limit(β{sub N} ∼ 4) transiently and higher stored energy region is obtained by increased total heating power (∼6 MW) and plasma current (I{sub p} up to 1 MA for ∼10 s). Heating system consists of various mixtures (NB, ECH, LHCD, ICRF) but the major horse heating resource is the neutral beam(NB) of 100 keV with 4.5 MW and most of experiments are conducted with NB. So there is a lot of production of fast neutrons coming from via D(d,n){sup 3}He reaction and it is found that most of neutrons are coming from deuterium beam plasma interaction. Nominal neutron yield and the area of beam port is about 10{sup 13}–10{sup 14}/s and 1 m{sup 2} at the closest access position of the sample respectively and neutron emission could be modulated for application to the neutron radiography by varying NB power. This work reports on the results of quantitative analysis of neutron emission measurements and results are discussed in terms of beam-plasma interaction and plasma confinement. It also includes the feasibility study of neutron radiography using KSTAR.

  2. Filtered neutron beams at the FMRB - review and current status

    International Nuclear Information System (INIS)

    Alberts, W.G.; Dietz, E.

    1987-12-01

    A review is presented of our experience with filtered neutron beams installed in beam tubes of the Research and Measurement Reactor Braunschweig since 1976: Desing of the filters and measurement of the beam parameters are reported and an outline of the research work done with the beams is given. The present status of the irradiation facility, which consists of 5 beams (144 keV, 24.5 keV, 2 keV, 0.2 keV and thermal neutrons), is described in some detail to allow understanding of the physical as well as the technical prerequisites for performing calibrations of neutron measuring instruments. An appendix contains the actual beam parameters. (orig.) [de

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

    International Nuclear Information System (INIS)

    Dien, Nguyen Nhi; Hai, Nguyen Canh

    2003-01-01

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

  4. Neutron production by neutral beam sources

    International Nuclear Information System (INIS)

    Berkner, K.H.; Massoletti, D.J.; McCaslin, J.B.; Pyle, R.V.; Ruby, L.

    1979-11-01

    Neutron yields, from interactions of multiampere 40- to 120-keV deuterium beams with deuterium atoms implanted in copper targets, have been measured in order to provide input data for shielding of neutral-deuterium beam facilities for magnetic fusion experiments

  5. Neutron production by neutral beam sources

    Energy Technology Data Exchange (ETDEWEB)

    Berkner, K.H.; Massoletti, D.J.; McCaslin, J.B.; Pyle, R.V.; Ruby, L.

    1979-11-01

    Neutron yields, from interactions of multiampere 40- to 120-keV deuterium beams with deuterium atoms implanted in copper targets, have been measured in order to provide input data for shielding of neutral-deuterium beam facilities for magnetic fusion experiments.

  6. Demonstration of the importance of a dedicated neutron beam monitoring system for BNCT facility

    International Nuclear Information System (INIS)

    Chao, Der-Sheng; Liu, Yuan-Hao; Jiang, Shiang-Huei

    2016-01-01

    The neutron beam monitoring system is indispensable to BNCT facility in order to achieve an accurate patient dose delivery. The neutron beam monitoring of a reactor-based BNCT (RB-BNCT) facility can be implemented through the instrumentation and control system of a reactor provided that the reactor power level remains constant during reactor operation. However, since the neutron flux in reactor core is highly correlative to complicated reactor kinetics resulting from such as fuel depletion, poison production, and control blade movement, some extent of variation may occur in the spatial distribution of neutron flux in reactor core. Therefore, a dedicated neutron beam monitoring system is needed to be installed in the vicinity of the beam path close to the beam exit of the RB-BNCT facility, where it can measure the BNCT beam intensity as closely as possible and be free from the influence of the objects present around the beam exit. In this study, in order to demonstrate the importance of a dedicated BNCT neutron beam monitoring system, the signals originating from the two in-core neutron detectors installed at THOR were extracted and compared with the three dedicated neutron beam monitors of the THOR BNCT facility. The correlation of the readings between the in-core neutron detectors and the BNCT neutron beam monitors was established to evaluate the improvable quality of the beam intensity measurement inferred by the in-core neutron detectors. In 29 sampled intervals within 16 days of measurement, the fluctuations in the mean value of the normalized ratios between readings of the three BNCT neutron beam monitors lay within 0.2%. However, the normalized ratios of readings of the two in-core neutron detectors to one of the BNCT neutron beam monitors show great fluctuations of 5.9% and 17.5%, respectively. - Highlights: • Two in-core neutron detectors and three BNCT neutron beam monitors were compared. • BNCT neutron beam monitors improve the stability in neutron

  7. Optimal Neutron Source and Beam Shaping Assembly for Boron Neutron Capture Therapy

    International Nuclear Information System (INIS)

    Vujic, J.; Greenspan, E.; Kastenber, W.E.; Karni, Y.; Regev, D.; Verbeke, J.M.; Leung, K.N.; Chivers, D.; Guess, S.; Kim, L.; Waldron, W.; Zhu, Y.

    2003-01-01

    There were three objectives to this project: (1) The development of the 2-D Swan code for the optimization of the nuclear design of facilities for medical applications of radiation, radiation shields, blankets of accelerator-driven systems, fusion facilities, etc. (2) Identification of the maximum beam quality that can be obtained for Boron Neutron Capture Therapy (BNCT) from different reactor-, and accelerator-based neutron sources. The optimal beam-shaping assembly (BSA) design for each neutron source was also to e obtained. (3) Feasibility assessment of a new neutron source for NCT and other medical and industrial applications. This source consists of a state-of-the-art proton or deuteron accelerator driving and inherently safe, proliferation resistant, small subcritical fission assembly

  8. Prospects for a new cold neutron beam measurement of the neutron lifetime

    Energy Technology Data Exchange (ETDEWEB)

    Dewey, M., E-mail: mdewey@nist.go [National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States); Coakley, K., E-mail: kevin.coakley@nist.go [National Institute of Standards and Technology, Boulder, CO 80305 (United States); Gilliam, D., E-mail: david.gilliam@nist.go [National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States); Greene, G., E-mail: greenegl@ornl.go [Department of Physics, University of Tennessee, Knoxville, TN 37996 (United States); Physics Division, Oak Ridge National Lab, Building 6010, Oak Ridge, TN 37831 (United States); Laptev, A., E-mail: alaptev@nist.go [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Nico, J., E-mail: jnico@nist.go [National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States); Snow, W., E-mail: wsnow@indiana.ed [Indiana University/IUCF, Bloomington, IN 47408 (United States); Wietfeldt, F., E-mail: few@tulane.ed [Tulane University, New Orleans, LA 70118 (United States); Yue, A., E-mail: ayue@nist.go [Department of Physics, University of Tennessee, Knoxville, TN 37996 (United States)

    2009-12-11

    In the most accurate cold neutron beam determination of the neutron lifetime based on the absolute counting of decay protons, the largest uncertainty was attributed to the absolute determination of the capture flux of the cold neutron beam. Currently an experimental effort is underway at the National Institute of Standards and Technology (NIST) that will significantly reduce this contribution to the uncertainty in the lifetime determination. The next largest source of uncertainty is the determination of the absolute count rate of decay protons, which contributes to the experimental uncertainty approximately at the 1 s level. Experience with the recent neutron radiative decay experiment, which used the neutron lifetime apparatus, has provided valuable insights into ways to reduce other uncertainties. In addition, the cold neutron fluence rate at NIST is presently 1.5 times greater than in the 2003 measurement, and there is the prospect for a significantly higher rate with the new guide hall expansion. This paper discusses an approach for achieving a determination of the neutron lifetime with an accuracy of approximately 1 s.

  9. Determination of the neutron energy and spatial distributions of the neutron beam from the TSR-II in the large beam shield

    International Nuclear Information System (INIS)

    Clifford, C.E.; Muckenthaler, F.J.

    1976-01-01

    The TSR-II reactor of the ORNL Tower Shielding Facility has recently been relocated within a new, fixed shield. A principal feature of the new shield is a beam port of considerably larger area than that of its predecessor. The usable neutron flux has thereby been increased by a factor of approximately 200. The bare beam neutron spectrum behind the new shield has been experimentally determined over the energy range from 0.8 to 16 MeV. A high level of fission product gamma ray background prevented measurement of bare beam spectra below 0.8 MeV, however neutron spectra in the energy range from 8 keV to 1.4 MeV were obtained for two simple, calculable shielding configurations. Also measured in the present work were weighted integral flux distributions and fast neutron dose rates

  10. Optimization study for an epithermal neutron beam for boron neutron capture therapy at the University of Virginia Research Reactor

    International Nuclear Information System (INIS)

    Burns, T.D. Jr.

    1995-05-01

    The non-surgical brain cancer treatment modality, Boron Neutron Capture Therapy (BNCT), requires the use of an epithermal neutron beam. This purpose of this thesis was to design an epithermal neutron beam at the University of Virginia Research Reactor (UVAR) suitable for BNCT applications. A suitable epithermal neutron beam for BNCT must have minimal fast neutron and gamma radiation contamination, and yet retain an appreciable intensity. The low power of the UVAR core makes reaching a balance between beam quality and intensity a very challenging design endeavor. The MCNP monte carlo neutron transport code was used to develop an equivalent core radiation source, and to perform the subsequent neutron transport calculations necessary for beam model analysis and development. The code accuracy was validated by benchmarking output against experimental criticality measurements. An epithermal beam was designed for the UVAR, with performance characteristics comparable to beams at facilities with cores of higher power. The epithermal neutron intensity of this beam is 2.2 x 10 8 n/cm 2 · s. The fast neutron and gamma radiation KERMA factors are 10 x 10 -11 cGy·cm 2 /n epi and 20 x 10 -11 cGy·cm 2 /n epi , respectively, and the current-to-flux ratio is 0.85. This thesis has shown that the UVAR has the capability to provide BNCT treatments, however the performance characteristics of the final beam of this study were limited by the low core power

  11. Achievement and development of neutron beam utilization in research reactors

    International Nuclear Information System (INIS)

    Isshiki, Masahiko

    1996-01-01

    Especially regarding the neutron beam experiment in Japan, the basic research has been developed by utilizing the JRR-2 of Japan Atomic Energy Research Institute and the KUR of Kyoto University over long years. Now, the JRR-3M of JAERI was revived as a high performance, general purpose reactor, and bears important roles as the neutron beam experiment center in Japan. Thanks to one of the most powerful reactor neutron sources in the world and the cold neutron source, the environment of research was greatly improved, and the excellent results of researches began to be reported. The discovery of neutrons by Chadwick and the history of the related researches are described. As neutron sources, radioisotopes, accelerators and nuclear reactors are properly used corresponding to purposes. As the utilization of research reactors for neutron sources, the utilization for irradiation and neutron beam experiment are carried out. The outline of the research reactor JRR-3M is explained. The state of utilization in neutron scattering experiment, neutron radiography, prompt γ-ray analysis and the medical irradiation of neutrons is reported. (K.I.)

  12. A low background pulsed neutron polyenergetic beam

    International Nuclear Information System (INIS)

    Adib, M.; Abdelkawy, A.; Habib, N.; abuelela, M.; Wahba, M.; kilany, M.; Kalebebin, S.M.

    1992-01-01

    A low background pulsed neutron polyenergetic thermal beam at ET-R R-1 is produced by a rotor and rotating collimator suspended in magnetic fields. Each of them is mounted on its mobile platform and whose centres are 66 cm apart, rotating synchronously at speeds up to 16000 rpm. It was found that the neutron burst produced by the rotor with almost 100% transmission passes through the collimator, when the rotation phase between them is 28.8 degree Moreover the background level achieved at the detector position is low, constant and free from peaks due to gamma rays and fast neutrons accompanying the reactor thermal beam.3 fig

  13. European protocol for neutron dosimetry for external beam therapy

    International Nuclear Information System (INIS)

    Broerse, J.J.; Mijnheer, B.J.; Williams, J.R.

    1981-01-01

    The paper attempts to serve the needs of European centres participating in the High LET Therapy Project Group set up under the sponsorship of The European Organization for Research on Treatment of Cancer, to promote cooperation between physicists involved in fast neutron therapy and establish a common basis for neutron dosimetry. Differences in dosimetry procedures between European and American Groups are indicated if relevant. The subject is dealt with under the following main headings: principles of dosimetry of neutron fields, dosimetric methods, physical parameters, determination of absorbed dose at a reference point, determination of absorbed dose at any point, check of absorbed dose given to a patient, dosimetry intercomparisons between institutes. There is an ample bibliography. (U.K.)

  14. Other applications of neutron beams in material sciences

    International Nuclear Information System (INIS)

    Novion, C.H. de

    1997-01-01

    The various applications of neutron beams are reviewed. The different mechanisms involved in neutron interaction with matter are explained. We notice that generally neutron radiation effects are unfavorable but can be turned into efficient tools to add new structures or properties to materials, silicon doping is an example. The basis principles of neutron activation analysis and neutron radiography are described. (A.C.)

  15. Beam splitting to improve target life in neutron generators

    International Nuclear Information System (INIS)

    Farrell, J.P.

    1976-01-01

    In a neutron generator in which a tritium-titanium target is bombarded by a deuterium ion beam, the target half-life is increased by separating the beam with a weak magnetic field to provide three separate beams of atomic, diatomic, and triatomic deuterium ions which all strike the target at different adjacent locations. Beam separation in this manner eliminates the problem of one type ion impairing the neutron generating efficiency of other type ions, thereby effecting more efficient utilization of the target material

  16. A spin-transport system for a longitudinally polarized epithermal neutron beam

    International Nuclear Information System (INIS)

    Crawford, B.E.; Bowman, J.D.; Penttilae, S.I.; Roberson, N.R.

    2001-01-01

    The TRIPLE (Time Reversal and Parity at Low Energies) collaboration uses a polarized epithermal neutron beam and a capture γ-ray detector to study parity violation in neutron-nucleus reactions. In order to preserve the spin polarization of the neutrons as they travel the 60-m path to the target, the beam pipes are wrapped with wire to produce a solenoidal magnetic field of about 10 G along the beam direction. The flanges and bellows between sections of the beam pipe cause gaps in the windings which in turn produce radial fields that can depolarize the neutron spins. A computer code has been developed that numerically evaluates the effect of these gaps on the polarization. A measurement of the neutron depolarization for neutrons in the actual spin-transport system agrees with a calculation of the neutron depolarization for the TRIPLE system. Features that will aid in designing similar spin-transport systems are discussed

  17. Development of the RRR cold neutron beam facility

    International Nuclear Information System (INIS)

    Lovotti, Osvaldo; Masriera, Nestor; Lecot, Carlos; Hergenreder, Daniel

    2002-01-01

    This paper describes some general design issues on the neutron beam facilities (cold neutron source and neutron beam transport system) of the Replacement Research Reactor (RRR) for the Australian Nuclear Science and Technology Organisation (ANSTO). The description covers different aspect of the design: the requirements that lead to an innovative design, the overall design itself, the definition of a technical approach in order to develop the necessary design solutions, and finally the organizational framework by which international expertise from five different institutions is integrated. From the technical viewpoint, the RRR-CNS is a liquid Deuterium (LD2) moderator, sub-cooled to ensure maximum moderation efficiency, flowing within a closed natural circulation thermosyphon loop. The thermosyphon is surrounded by a zirconium alloy CNS vacuum containment that provides thermal insulation and a multiple barriers scheme to prevent Deuterium from mixing with water or air. Consistent with international practice, this vessel is designed to withstand any hypothetical energy reaction should Deuterium and air mix in its interior. The 'cold' neutrons are then taken by the NBTS and transported by the neutron guide system into the reactor beam hall and neutron guide hall, where neutron scattering instruments are located. From the management viewpoint, the adopted distributed scheme is successful to manage the complex interfacing between highly specialized technologies, allowing a smooth integration within the project. (author)

  18. Upgrade for the epithermal neutron beam at NRI Rez

    International Nuclear Information System (INIS)

    Marek, M.; Flibor, S.; Viererbl, L.; Burian, J.; Rejchrt, J.; Klupak, V.; Gambarini, G.; Vanossi, E.

    2006-01-01

    The epithermal neutron beam facility designed for pre-clinical neutron capture therapy research has been operated at LVR-15 reactor for more than ten years. The construction of the beam filter has been recently modified especially for the shielding quality of the beam shutter to be improved. The parameters of the upgraded beam were calculated with the MCNP code and a new source term for the NCTPLAN treatment planning software was evaluated. The calculated source term was consequently scaled according to the results of measurements in the free beam and in the 50x50x25 cm 3 water phantom. (author)

  19. A neutron beam facility for radioactive ion beams and other applications

    Science.gov (United States)

    Tecchio, L. B.

    1999-06-01

    In the framework of the Italian participation in the project of a high intensity proton facility for the energy amplifier and nuclear waste transmutations, LNL is involved in the design and construction of same prototypes of the injection system of the 1 GeV linac that consists of a RFQ (5 MeV, 30 mA) followed by a 100 MeV linac. This program has already been supported financially and the work is in progress. In this context LNL has proposed a project for the construction of a second generation facility for the production of radioactive ion beams (RIBs) by means of the ISOL method. The final goal is the production of neutron rich RIBs with masses ranging from 30 to 150 by using primary beams of protons, deuterons and light ions with energy of 100 MeV and 100 kW power. This project is expected to be developed in about 10 years from new and intermediate milestones and experiments are foreseen and under consideration for the next INFN five year plan (1999-2003). During that period the construction of a proton/deuteron accelerator of 10 MeV energy and 10 mA current, consisting of a RFQ (5 MeV, 30 mA) and a linac (10 MeV, 10 mA), and of a neutron area dedicated to the RIBs production and to the neutron physics, is proposed. Some remarks on the production methods will be presented. The possibility of producing radioisotopes by means of the fission induced by neutrons will be investigated and the methods of production of neutrons will be discussed. Besides the RIBs production, neutron beams for the BNCT applications and neutron physics are also planned.

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

    CERN Document Server

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

    2003-01-01

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

  1. GEM-based thermal neutron beam monitors for spallation sources

    International Nuclear Information System (INIS)

    Croci, G.; Claps, G.; Caniello, R.; Cazzaniga, C.; Grosso, G.; Murtas, F.; Tardocchi, M.; Vassallo, E.; Gorini, G.; Horstmann, C.; Kampmann, R.; Nowak, G.; Stoermer, M.

    2013-01-01

    The development of new large area and high flux thermal neutron detectors for future neutron spallation sources, like the European Spallation Source (ESS) is motivated by the problem of 3 He shortage. In the framework of the development of ESS, GEM (Gas Electron Multiplier) is one of the detector technologies that are being explored as thermal neutron sensors. A first prototype of GEM-based thermal neutron beam monitor (bGEM) has been built during 2012. The bGEM is a triple GEM gaseous detector equipped with an aluminum cathode coated by 1μm thick B 4 C layer used to convert thermal neutrons to charged particles through the 10 B(n, 7 Li)α nuclear reaction. This paper describes the results obtained by testing a bGEM detector at the ISIS spallation source on the VESUVIO beamline. Beam profiles (FWHM x =31 mm and FWHM y =36 mm), bGEM thermal neutron counting efficiency (≈1%), detector stability (3.45%) and the time-of-flight spectrum of the beam were successfully measured. This prototype represents the first step towards the development of thermal neutrons detectors with efficiency larger than 50% as alternatives to 3 He-based gaseous detectors

  2. Off-axis dose equivalent due to secondary neutrons from uniform scanning proton beams during proton radiotherapy

    Science.gov (United States)

    Islam, M. R.; Collums, T. L.; Zheng, Y.; Monson, J.; Benton, E. R.

    2013-11-01

    The production of secondary neutrons is an undesirable byproduct of proton therapy and it is important to quantify the contribution from secondary neutrons to patient dose received outside the treatment volume. The purpose of this study is to investigate the off-axis dose equivalent from secondary neutrons experimentally using CR-39 plastic nuclear track detectors (PNTD) at ProCure Proton Therapy Center, Oklahoma City, OK. In this experiment, we placed several layers of CR-39 PNTD laterally outside the treatment volume inside a phantom and in air at various depths and angles with respect to the primary beam axis. Three different proton beams with max energies of 78, 162 and 226 MeV and 4 cm modulation width, a 5 cm diameter brass aperture, and a small snout located 38 cm from isocenter were used for the entire experiment. Monte Carlo simulations were also performed based on the experimental setup using a simplified snout configuration and the FLUKA Monte Carlo radiation transport code. The measured ratio of secondary neutron dose equivalent to therapeutic primary proton dose (H/D) ranged from 0.3 ± 0.08 mSv Gy-1 for 78 MeV proton beam to 37.4 ± 2.42 mSv Gy-1 for 226 MeV proton beam. Both experiment and simulation showed a similar decreasing trend in dose equivalent with distance to the central axis and the magnitude varied by a factor of about 2 in most locations. H/D was found to increase as the energy of the primary proton beam increased and higher H/D was observed at 135° compared to 45° and 90°. The overall higher H/D in air indicates the predominance of external neutrons produced in the nozzle rather than inside the body.

  3. Off-axis dose equivalent due to secondary neutrons from uniform scanning proton beams during proton radiotherapy

    International Nuclear Information System (INIS)

    Islam, M R; Collums, T L; Monson, J; Benton, E R; Zheng, Y

    2013-01-01

    The production of secondary neutrons is an undesirable byproduct of proton therapy and it is important to quantify the contribution from secondary neutrons to patient dose received outside the treatment volume. The purpose of this study is to investigate the off-axis dose equivalent from secondary neutrons experimentally using CR-39 plastic nuclear track detectors (PNTD) at ProCure Proton Therapy Center, Oklahoma City, OK. In this experiment, we placed several layers of CR-39 PNTD laterally outside the treatment volume inside a phantom and in air at various depths and angles with respect to the primary beam axis. Three different proton beams with max energies of 78, 162 and 226 MeV and 4 cm modulation width, a 5 cm diameter brass aperture, and a small snout located 38 cm from isocenter were used for the entire experiment. Monte Carlo simulations were also performed based on the experimental setup using a simplified snout configuration and the FLUKA Monte Carlo radiation transport code. The measured ratio of secondary neutron dose equivalent to therapeutic primary proton dose (H/D) ranged from 0.3 ± 0.08 mSv Gy −1  for 78 MeV proton beam to 37.4 ± 2.42 mSv Gy −1  for 226 MeV proton beam. Both experiment and simulation showed a similar decreasing trend in dose equivalent with distance to the central axis and the magnitude varied by a factor of about 2 in most locations. H/D was found to increase as the energy of the primary proton beam increased and higher H/D was observed at 135° compared to 45° and 90°. The overall higher H/D in air indicates the predominance of external neutrons produced in the nozzle rather than inside the body. (paper)

  4. Tailoring phase-space in neutron beam extraction

    Energy Technology Data Exchange (ETDEWEB)

    Weichselbaumer, S. [Heinz Maier-Leibnitz Zentrum und Physik-Department E21, Technische Universität München, Lichtenbergstr. 1, D-85748 Garching (Germany); Brandl, G. [Heinz Maier-Leibnitz Zentrum und Physik-Department E21, Technische Universität München, Lichtenbergstr. 1, D-85748 Garching (Germany); Physik-Department E21, Technische Universität München, James-Franck-Str. 1, D-85748 Garching (Germany); Georgii, R., E-mail: Robert.Georgii@frm2.tum.de [Heinz Maier-Leibnitz Zentrum und Physik-Department E21, Technische Universität München, Lichtenbergstr. 1, D-85748 Garching (Germany); Physik-Department E21, Technische Universität München, James-Franck-Str. 1, D-85748 Garching (Germany); Stahn, J. [Laboratory for Neutron Scattering, Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Panzner, T. [Material Science and Simulations, Neutrons and Muons, Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Böni, P. [Physik-Department E21, Technische Universität München, James-Franck-Str. 1, D-85748 Garching (Germany)

    2015-09-01

    In view of the trend towards smaller samples and experiments under extreme conditions it is important to deliver small and homogeneous neutron beams to the sample area. For this purpose, elliptic and/or Montel mirrors are ideally suited as the phase space of the neutrons can be defined far away from the sample. Therefore, only the useful neutrons will arrive at the sample position leading to a very low background. We demonstrate the ease of designing neutron transport systems using simple numeric tools, which are verified using Monte-Carlo simulations that allow taking into account effects of gravity and finite beam size. It is shown that a significant part of the brilliance can be transferred from the moderator to the sample. Our results may have a serious impact on the design of instruments at spallation sources such as the European Spallation Source (ESS) in Lund, Sweden.

  5. CONTINOUS EXTRACTED BEAM IN THE AGS FAST EXTERNAL BEAM LINE

    International Nuclear Information System (INIS)

    GLENN, J.W.; TSOUPAS, N.; BROWN, K.A.; BIRYUKOV, V.M.

    2001-01-01

    A method to split off a few percent of the 6 x 10 13 AGS beam delivered to the Slow External Beam (SEB) lines and send it down the Fast External Beam line (FEB) has been developed. The mission is to feed a counter experiment off the FEB that directly measures the neutrino mass using the muon storage ring. The use of normal thin septum splitters would have an excessive loss overhead and been optically difficult. The AGS Slow Extraction uses a third integer resonance with sextuple strength so the resonance width is a few percent of the beam width. This results in a low density tail which will be clipped by a bent crystal and deflected into the FEB channel. This clipping off of the tail should reduce losses in the SEB transport line. Details of modeled orbits, particle distribution and extraction trajectories into and out off the crystal will be given

  6. The first neutron beam hits EAR2

    CERN Multimedia

    Antonella Del Rosso

    2014-01-01

    On 25 July 2014, about a year after construction work began, the Experimental Area 2 (EAR2) of CERN’s neutron facility n_TOF recorded its first beam. Unique in many aspects, EAR2 will start its rich programme of experimental physics this autumn.   The last part of the EAR2 beamline: the neutrons come from the underground target and reach the top of the beamline, where they hit the samples. Built about 20 metres above the neutron production target, EAR2 is in fact a bunker connected to the n_TOF underground facilities via a duct 80 cm in diameter, where the beamline is installed. The feet of the bunker support pillars are located on the concrete structure of the n_TOF tunnel and part of the structure lies above the old ISR building. A beam dump located on the roof of the building completes the structure. Neutrons are used by physicists to study neutron-induced reactions with applications in a number of fields, including nuclear waste transmutation, nuclear technology, nuclear astrop...

  7. The Spallation Neutron Source Beam Commissioning and Initial Operations

    Energy Technology Data Exchange (ETDEWEB)

    Henderson, Stuart [Argonne National Lab. (ANL), Argonne, IL (United States); Aleksandrov, Alexander V. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Allen, Christopher K. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Assadi, Saeed [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bartoski, Dirk [University of Texas, Houston, TX (United States). Anderson Cancer Center; Blokland, Willem [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Casagrande, F. [Michigan State Univ., East Lansing, MI (United States); Campisi, I. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Chu, C. [Michigan State Univ., East Lansing, MI (United States); Cousineau, Sarah M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Crofford, Mark T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Danilov, Viatcheslav [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Deibele, Craig E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Dodson, George W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Feshenko, A. [Inst. for Nuclear Research (INR), Moscow (Russian Federation); Galambos, John D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Han, Baoxi [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hardek, T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Holmes, Jeffrey A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Holtkamp, N. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Howell, Matthew P. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jeon, D. [Inst. for Basic Science, Daejeon (Korea); Kang, Yoon W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kasemir, Kay [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kim, Sang-Ho [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kravchuk, L. [Institute for Nuclear Research (INR), Moscow (Russian Federation); Long, Cary D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); McManamy, T. [McManamy Consulting, Inc., Middlesex, MA (United States); Pelaia, II, Tom [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Piller, Chip [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Plum, Michael A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Pogge, James R. [Tennessee Technological Univ., Cookeville, TN (United States); Purcell, John David [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Shea, T. [European Spallation Source, Lund (Sweden); Shishlo, Andrei P [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Sibley, C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Stockli, Martin P. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Stout, D. [Michigan State Univ., East Lansing, MI (United States); Tanke, E. [European Spallation Source, Lund (Sweden); Welton, Robert F [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Zhang, Y. [Michigan State Univ., East Lansing, MI (United States); Zhukov, Alexander P [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-09-01

    The Spallation Neutron Source (SNS) accelerator delivers a one mega-Watt beam to a mercury target to produce neutrons used for neutron scattering materials research. It delivers ~ 1 GeV protons in short (< 1 us) pulses at 60 Hz. At an average power of ~ one mega-Watt, it is the highest-powered pulsed proton accelerator. The accelerator includes the first use of superconducting RF acceleration for a pulsed protons at this energy. The storage ring used to create the short time structure has record peak particle per pulse intensity. Beam commissioning took place in a staged manner during the construction phase of SNS. After the construction, neutron production operations began within a few months, and one mega-Watt operation was achieved within three years. The methods used to commission the beam and the experiences during initial operation are discussed.

  8. Upgrades of the epithermal neutron beam at the Brookhaven Medical Research Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Hungyuan B.; Brugger, R.M.; Rorer, D.C.

    1994-12-31

    The first epithermal neutron beam at the Brookhaven Medical Research Reactor (BMRR) was installed in 1988 and produced a neutron beam that was satisfactory for the development of NCT with epithermal neutrons. This beam was used routinely until 1992 when the beam was upgraded by rearranging fuel elements in the reactor core to achieve a 50% increase in usable flux. Next, after computer modeling studies, it was proposed that the Al and Al{sub 2}O{sub 3} moderator material in the shutter that produced the epithermal neutrons could be rearranged to enhance the beam further. However, this modification was not started because a better option appeared, namely to use fission plates to move the source of fission neutrons closer to the moderator and the patient irradiation position to achieve more efficient moderation and production of epithermal neutrons. A fission plate converter (FPC) source has been designed recently and, to test the concept, implementation of this upgrade has started. The predicted beam parameters will be 12 x 10{sup 9} n{sub epi}/cm{sup 2}sec accompanying with doses from fast neutrons and gamma rays per epithermal neutron of 2.8 x 10{sup -11} and < 1 x 10{sup -11} cGycm{sup 2}/n, respectively, and a current-to-flux ratio of epithermal neutrons of 0.78. This conversion could be completed by late 1996.

  9. Characterization of a Neutron Beam Following Reconfiguration of the Neutron Radiography Reactor (NRAD Core and Addition of New Fuel Elements

    Directory of Open Access Journals (Sweden)

    Aaron E. Craft

    2016-02-01

    Full Text Available The neutron radiography reactor (NRAD is a 250 kW Mark-II Training, Research, Isotopes, General Atomics (TRIGA reactor at Idaho National Laboratory, Idaho Falls, ID, USA. The East Radiography Station (ERS is one of two neutron beams at the NRAD used for neutron radiography, which sits beneath a large hot cell and is primarily used for neutron radiography of highly radioactive objects. Additional fuel elements were added to the NRAD core in 2013 to increase the excess reactivity of the reactor, and may have changed some characteristics of the neutron beamline. This report discusses characterization of the neutron beamline following the addition of fuel to the NRAD. This work includes determination of the facility category according to the American Society for Testing and Materials (ASTM standards, and also uses an array of gold foils to determine the neutron beam flux and evaluate the neutron beam profile. The NRAD ERS neutron beam is a Category I neutron radiography facility, the highest possible quality level according to the ASTM. Gold foil activation experiments show that the average neutron flux with length-to-diameter ratio (L/D = 125 is 5.96 × 106 n/cm2/s with a 2σ standard error of 2.90 × 105 n/cm2/s. The neutron beam profile can be considered flat for qualitative neutron radiographic evaluation purposes. However, the neutron beam profile should be taken into account for quantitative evaluation.

  10. Shear behavior of concrete beams externally prestressed with Parafil ropes

    Directory of Open Access Journals (Sweden)

    A.H. Ghallab

    2013-03-01

    Full Text Available Although extensive work has been carried out investigating the use of external prestressing system for flexural strengthening, a few studies regarding the shear behavior of externally prestressed beams can be found. Five beams, four of them were externally strengthened using Parafil rope, were loaded up to failure to investigate the effect of shear span/depth ratio, external prestressing force and concrete strength on their shear behavior. Test results showed that the shear span to depth ratio has a significant effect on both the shear strength and failure mode of the strengthened beams and the presence of external prestressing force increased the ultimate load of the tested beams by about 75%. Equations proposed by different codes for both the conventional reinforced concrete beams and for ordinary prestressed beams were used to evaluate the obtained experimental results. In general, codes equations showed a high level of conservatism in predicting the shear strength of the beams. Also, using the full strength rather than half of the concrete shear strength in the Egyptian code PC-method improves the accuracy of the calculated ultimate shear strength.

  11. Using MCNP-4C code for design of the thermal neutron beam for neutron radiography at the MNSR

    International Nuclear Information System (INIS)

    Shaaban, I.

    2009-11-01

    Studies were carried out for determination of the parameters of a thermal neutron beam at the MNSR reactor (MNSR-30 kW) for neutron radiography in the vertical beam port by using the MCNP-4C (Monte Carlo Neutron - Photon transport). Thermal, epithermal and fast neutron energy ranges were selected as 10 keV respectively. To produce a good neutron beam in terms of intensity and quality, several materials Lead (Pb), Bismuth (Bi), Borated polyethelyene and Alumina Oxide (Al 2 O 3 ) were used as neutron and photon filters. Based on the current design, the L/D of the facility ranges between 125, 110 and 90. The thermal neutron flux at the beam exit is 1.436x10 5 n/cm2 .s ,1.843x10 5 n/cm2 .s and 2.845x10 5 n/cm2 .s respectively, middots with a Cd-ratio of ∼ 2.829, 2.766, 3.191 for the L/D = 125, 110, 90 respectively. The estimated values for gamma doses are 6.705x10 -2 Rem/h and 1.275x10 -1 Rem/h and 2.678x10 -1 Rem/ h with bismuth. The divergent angle of the collimator is 1.348 degree - 2.021 degree. Such neutron beams, if built into the Syrian MNSR reactor, could support the application of NRG in Syria. (author)

  12. Targets for neutron beam spallation sources

    International Nuclear Information System (INIS)

    Bauer, G.S.

    1980-01-01

    The meeting on Targets for Neutron Beam Spallation Sources held at the Institut fuer Festkoerperforschung at KFA Juelich on June 11 and 12, 1979 was planned as an informal get-together for scientists involved in the planning, design and future use of spallation neutron sources in Europe. These proceedings contain the papers contributed to this meeting. For further information see hints under relevant topics. (orig./FKS)

  13. Radiation protection commissioning of neutron beam instruments at the OPAL research reactor

    International Nuclear Information System (INIS)

    Parkes, Alison; Saratsopoulos, John; Deura, Michael; Kenny, Pat

    2008-01-01

    The neutron beam facilities at the 20 MW OPAL Research Reactor were commissioned in 2007 and 2008. The initial suite of eight neutron beam instruments on two thermal neutron guides, two cold neutron guides and one thermal beam port located at the reactor face, together with their associated shielding were progressively installed and commissioned according to their individual project plans. Radiation surveys were systematically conducted as reactor power was raised in a step-wise manner to 20 MW in order to validate instrument shielding design and performance. The performance of each neutron guide was assessed by neutron energy spectrum and flux measurements. The activation of beam line components, decay times assessments and access procedures for Bragg Institute beam instrument scientists were established. The multiple configurations for each instrument and the influence of operating more than one instrument or beamline simultaneously were also tested. Areas of interest were the shielding around the secondary shutters, guide shield and bunker shield interfaces and monochromator doors. The shielding performance, safety interlock checks, improvements, radiation exposures and related radiation protection challenges are discussed. This paper discusses the health physics experience of commissioning the OPAL Research Reactor neutron beam facilities and describes health physics results, actions taken and lessons learned during commissioning. (author)

  14. In vitro biological effectiveness of JRR-4 epithermal neutron beam. Experiment under free air beam and in water phantom. Cooperative research

    CERN Document Server

    Yamamoto, T; Horiguchi, Y; Kishi, T; Kumada, H; Matsumura, A; Nose, T; Torii, Y; Yamamoto, K

    2002-01-01

    The surviving curve and the biological effectiveness factor of dose components generated in boron neutron capture therapy (BNCT) were separately determined in neutron beams at Japan Research Reactor No.4. Surviving fraction of V79 Chinese hamster cell with or without sup 1 sup 0 B was obtained using an epithermal neutron beam (ENB), a mixed thermal-epithermal neutron beam (TNB-1), and a thermal neutron beam (TNB-2), which were used or planned to use for BNCT clinical trial. The cell killing effect of these neutron beams with or without the presence of sup 1 sup 0 B depended highly on the neutron beam used, according to the epithermal and fast neutron content in the beam. The biological effectiveness factor values of the boron capture reaction for ENB, TNB-1 and TNB-2 were 3.99+-0.24, 3.04+-0.19 and 1.43+-0.08, respectively. The biological effectiveness factor values of the high-LET dose components based on the hydrogen recoils and the nitrogen capture reaction were 2.50+-0.32, 2.34+-0.30 and 2.17+-0.28 for EN...

  15. Inverse kinetics for subcritical systems with external neutron source

    International Nuclear Information System (INIS)

    Carvalho Gonçalves, Wemerson de; Martinez, Aquilino Senra; Carvalho da Silva, Fernando

    2017-01-01

    Highlights: • It was developed formalism for reactivity calculation. • The importance function is related to the system subcriticality. • The importance function is also related with the value of the external source. • The equations were analyzed for seven different levels of sub criticality. • The results are physically consistent with others formalism discussed in the paper. - Abstract: Nuclear reactor reactivity is one of the most important properties since it is directly related to the reactor control during the power operation. This reactivity is influenced by the neutron behavior in the reactor core. The time-dependent neutrons behavior in response to any change in material composition is important for the reactor operation safety. Transient changes may occur during the reactor startup or shutdown and due to accidental disturbances of the reactor operation. Therefore, it is very important to predict the time-dependent neutron behavior population induced by changes in neutron multiplication. Reactivity determination in subcritical systems driven by an external neutron source can be obtained through the solution of the inverse kinetics equation for subcritical nuclear reactors. The main purpose of this paper is to find the solution of the inverse kinetics equation the main purpose of this paper is to device the inverse kinetics equations for subcritical systems based in a previous paper published by the authors (Gonçalves et al., 2015) and by (Gandini and Salvatores, 2002; Dulla et al., 2006). The solutions of those equations were also obtained. Formulations presented in this paper were tested for seven different values of k eff with external neutrons source constant in time and for a powers ratio varying exponentially over time.

  16. Influence of the external neutron sources in the criticality prediction using 1/M curve

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Valmir [COPPE/UFRJ, Programa de Engenharia Nuclear, Caixa Postal 68509, 21941-972 Rio de Janeiro (Brazil); Carvalho da Silva, Fernando [COPPE/UFRJ, Programa de Engenharia Nuclear, Caixa Postal 68509, 21941-972 Rio de Janeiro (Brazil); Martinez, Aquilino Senra [COPPE/UFRJ, Programa de Engenharia Nuclear, Caixa Postal 68509, 21941-972 Rio de Janeiro (Brazil)]. E-mail: aquilino@lmp.ufrj.br

    2005-11-15

    The influence of external neutron sources in the process to obtain the criticality condition is estimated. To reach this objective, the three-dimensional neutron diffusion equation in two groups of energy is solved, for a subcritical PWR reactor core with external neutron sources. The results are compared with the solution of the corresponding problem without external neutron sources, that is an eigenvalue problem. The method developed for this purposes it makes use of both the nodal method (for calculation of the neutron flux) and the finite differences method (for calculation of the adjoint flux). A coarse mesh finite difference method was developed for the adjoint flux calculation, which uses the output of the nodal expansion method. The results regarding the influence of the external neutron source presence for attaining criticality have shown that far from criticality it is necessary to calculate the reactivity values of the system.

  17. Influence of the external neutron sources in the criticality prediction using 1/M curve

    International Nuclear Information System (INIS)

    Pereira, Valmir; Carvalho da Silva, Fernando; Martinez, Aquilino Senra

    2005-01-01

    The influence of external neutron sources in the process to obtain the criticality condition is estimated. To reach this objective, the three-dimensional neutron diffusion equation in two groups of energy is solved, for a subcritical PWR reactor core with external neutron sources. The results are compared with the solution of the corresponding problem without external neutron sources, that is an eigenvalue problem. The method developed for this purposes it makes use of both the nodal method (for calculation of the neutron flux) and the finite differences method (for calculation of the adjoint flux). A coarse mesh finite difference method was developed for the adjoint flux calculation, which uses the output of the nodal expansion method. The results regarding the influence of the external neutron source presence for attaining criticality have shown that far from criticality it is necessary to calculate the reactivity values of the system

  18. Characterization of weak, fair and strong neutron absorbing materials by means of neutron transmission: Beam hardening effect

    Science.gov (United States)

    Kharfi, F.; Bastuerk, M.; Boucenna, A.

    2006-09-01

    The characterization of neutron absorbing materials as well as quantification of neutron attenuation through matter is very essential in various fields, namely in shielding calculation. The objective of this work is to describe an experimental procedure to be used for the determination of neutron transmission through different materials. The proposed method is based on the relation between the gray value measured on neutron radiography image and the corresponding inducing neutron beam. For such a purpose, three kinds of materials (in shape of plate) were investigated using thermal neutrons: (1) boron-alloyed stainless steel as strong absorber; (2) copper and steel as fair absorbers and (3) aluminum as weak absorber. This work is not limited to the determination of neutron transmission through matters; it is also spread out to the measure of the surface density of the neutron absorbing elements (ρs) as a function of thickness of neutron absorbing material such as boron-alloyed stainless steel. The beam hardening effect depending on material thickness was also studied using the neutron transmission measurements. A theoretical approach was used to interpret the experimental results. The neutron transmission measurements were performed at the Neutron Radiography and Tomography facility of the Atomic Institute of the Austrian Universities in Vienna. Finally, a Maxwellian neutron distribution of incident neutron beam was used in the theoretical calculations of neutron energy shift in order to compare with experiments results. The obtained experimental results are in a good agreement with the developed theoretical approach.

  19. Optimizing Laser-accelerated Ion Beams for a Collimated Neutron Source

    International Nuclear Information System (INIS)

    Ellison, C.L.; Fuchs, J.

    2010-01-01

    High-flux neutrons for imaging and materials analysis applications have typically been provided by accelerator- and reactor-based neutron sources. A novel approach is to use ultraintense (>1018W/cm2) lasers to generate picosecond, collimated neutrons from a dual target configuration. In this article, the production capabilities of present and upcoming laser facilities are estimated while independently maximizing neutron yields and minimizing beam divergence. A Monte-Carlo code calculates angular and energy distributions of neutrons generated by D-D fusion events occurring within a deuterated target for a given incident beam of D+ ions. Tailoring of the incident distribution via laser parameters and microlens focusing modifies the emerging neutrons. Projected neutron yields and distributions are compared to conventional sources, yielding comparable on-target fluxes per discharge, shorter time resolution, larger neutron energies and greater collimation.

  20. Beam intensity monitoring for the external proton beam at LAMPF

    International Nuclear Information System (INIS)

    Barrett, R.J.; Anderson, B.D.; Willard, H.B.; Anderson, A.N.; Jarmie, N.

    1975-07-01

    Three different intensity monitors were tested in the external proton beam at LAMPF, and together cover the entire range of beam currents available. A 800 kg Faraday cup was installed and used to measure the absolute intensity to better than 1 percent for beam currents up to several nanoamperes. A high gain ion chamber was used as part of the calibration procedure for the Faraday cup, and was found to be useful when monitoring very small beam intensities, being reliable down to the few picoampere level. A secondary emission monitor was also tested, calibrated, and found to be trustworthy only for beams of greater than 50 pA intensity. (auth)

  1. Intermediate-energy neutron beam for NCT at MURR

    International Nuclear Information System (INIS)

    Brugger, R.M.; Less, T.J.; Passmore, G.G.

    1986-01-01

    The University of Missouri Research Reactor (MURR) is one of the high-flux reactors in the USA and it can be used to produce an intense beam of intermediate-energy neutrons for neutron capture therapy. Two methods are being evaluated at MURR to produce such a beam. The first uses a moderator of Al 2 O 3 replacing part of the graphite and water on one side of the core of the reactor to produce a source of predominantly intermediate-energy neutrons. The second method is a filter of 238 U between the core and the patient position to pass only intermediate-energy neutrons. The results of these evaluations are presented in this paper along with an outline of the other resources at the University of Missouri-Columbia that are available to support an NCT program. 4 references, 7 figures, 1 table

  2. In vitro biological effectiveness of JRR-4 epithermal neutron beam. Experiment under free air beam and in water phantom. Cooperative research

    International Nuclear Information System (INIS)

    Yamamoto, Tetsuya; Matsumura, Akira; Nose, Tadao; Yamamoto, Kazuyoshi; Kumada, Hiroaki; Kishi, Toshiaki; Hori, Naohiko; Torii, Yoshiya; Horiguchi, Yoji

    2002-05-01

    The surviving curve and the biological effectiveness factor of dose components generated in boron neutron capture therapy (BNCT) were separately determined in neutron beams at Japan Research Reactor No.4. Surviving fraction of V79 Chinese hamster cell with or without 10 B was obtained using an epithermal neutron beam (ENB), a mixed thermal-epithermal neutron beam (TNB-1), and a thermal neutron beam (TNB-2), which were used or planned to use for BNCT clinical trial. The cell killing effect of these neutron beams with or without the presence of 10 B depended highly on the neutron beam used, according to the epithermal and fast neutron content in the beam. The biological effectiveness factor values of the boron capture reaction for ENB, TNB-1 and TNB-2 were 3.99±0.24, 3.04±0.19 and 1.43±0.08, respectively. The biological effectiveness factor values of the high-LET dose components based on the hydrogen recoils and the nitrogen capture reaction were 2.50±0.32, 2.34±0.30 and 2.17±0.28 for ENB, TNB-1 and TNB-2, respectively. The biological effectiveness factor values of the neutron and photon components were 1.22±0.16, 1.23±0.16 and 1.21±0.16, respectively. The depth function of biological effectiveness factor in water phantom and the difference in biological effectiveness factor among boron compounds were also determined. The experimental determination of biological effectiveness factor outlined in this paper is applicable to the dose calculation for each dose component of the neutron beams and contribute to an accurate biological effectiveness factor as comparison with a neutron beam at a different facility employed in ongoing and planned BNCT clinical trials. (author)

  3. Neutron beam instruments at Harwell

    International Nuclear Information System (INIS)

    Baston, A.H.; Harris, D.H.C.

    1978-11-01

    A list and brief descriptions are given of the neutron beam facilities for U.K. scientists at Harwell and in academic institutions, available under an agreement between the Science Research Council and AERE (Harwell). The list falls under the following headings: reactor instruments (single crystal diffractometers, powder diffractometers, triple axis spectrometers, time-of-flight cold neutron twin rotor spectrometer, beryllium filter spectrometer, MARX spectrometer, Harwell small-angle scattering spectrometer); LINAC instruments (total scattering spectrometer, back scattering spectrometer, active sample spectrometer, inelastic rotor spectrometer, constant Q spectrometer); ancillary equipment (cryostats, superconducting magnets, electromagnets, furnaces). (U.K.)

  4. Dosimetric properties of the fast neutron therapy beams at TAMVEC

    International Nuclear Information System (INIS)

    Almond, P.R.; Smith, A.R.; Smathers, J.R.; Otte, V.A.

    1975-01-01

    In October 1972, M.D. Anderson Hospital and Tumor Institute of the University of Texas System Cancer Center initiated a clinical trial of fast neutron radiotherapy using the cyclotron at Texas A and M University. Initially, the study used neutrons produced by bombarding beryllium with 16 MeV deuterons, but since March, 1973, neutrons from 50 MeV deuterons have been used. The dosimetric properties of the 30 MeV beams have also been measured for comparison with the neutron beams from D-T generators. The three beams are compared in terms of dose rate, skin sparing, depth dose and field flatness. Isodose curves for treatment planning were generated using the decrement line method and compared to curves measured by a computer controlled isodose plotter. This system was also used to measure the isodose curves for wedge fields. Dosimetry checks on various patients were made using silicon diodes as in vivo fast neutron dosimeters

  5. Neutron beam measurement dosimetry

    International Nuclear Information System (INIS)

    Amaro, C.R.

    1995-01-01

    This report describes animal dosimetry studies and phantom measurements. During 1994, 12 dogs were irradiated at BMRR as part of a 4 fraction dose tolerance study. The animals were first infused with BSH and irradiated daily for 4 consecutive days. BNL irradiated 2 beagles as part of their dose tolerance study using BPA fructose. In addition, a dog at WSU was irradiated at BMRR after an infusion of BPA fructose. During 1994, the INEL BNCT dosimetry team measured neutron flux and gamma dose profiles in two phantoms exposed to the epithermal neutron beam at the BMRR. These measurements were performed as a preparatory step to the commencement of human clinical trials in progress at the BMRR

  6. Neutron beam tomography software

    International Nuclear Information System (INIS)

    Newbery, A.C.R.

    1988-05-01

    When a sample is traversed by a neutron beam, inhomogeneities in the sample will cause deflections, and the deflections will permit conclusions to be drawn concerning the location and size of the inhomogeneities. The associated computation is similar to problems in tomography, analogous to X-ray tomography though significantly different in detail. We do not have any point-sample information, but only mean values over short line segments. Since each mean value is derived from a separate neutron counter, the quantity of available data has to be modest; also, since each datum is an integral, its geometric precision is inferior to that of X-ray data. Our software is designed to cope with these difficulties. (orig.) [de

  7. A measurement of the absolute neutron beam polarization produced by an optically pumped 3He neutron spin filter

    International Nuclear Information System (INIS)

    Rich, D.R.; Bowman, J.D.; Crawford, B.E.; Delheij, P.P.J.; Espy, M.A.; Haseyama, T.; Jones, G.; Keith, C.D.; Knudson, J.; Leuschner, M.B.; Masaike, A.; Masuda, Y.; Matsuda, Y.; Penttilae, S.I.; Pomeroy, V.R.; Smith, D.A.; Snow, W.M.; Szymanski, J.J.; Stephenson, S.L.; Thompson, A.K.; Yuan, V.

    2002-01-01

    The capability of performing accurate absolute measurements of neutron beam polarization opens a number of exciting opportunities in fundamental neutron physics and in neutron scattering. At the LANSCE pulsed neutron source we have measured the neutron beam polarization with an absolute accuracy of 0.3% in the neutron energy range from 40 meV to 10 eV using an optically pumped polarized 3 He spin filter and a relative transmission measurement technique. 3 He was polarized using the Rb spin-exchange method. We describe the measurement technique, present our results, and discuss some of the systematic effects associated with the method

  8. Magnetic compound refractive lens for focusing and polarizing cold neutron beams

    International Nuclear Information System (INIS)

    Littrell, K. C.; Velthuis, S. G. E. te; Felcher, G. P.; Park, S.; Kirby, B. J.; Fitzsimmons, M. R.

    2007-01-01

    Biconcave cylindrical lenses are used to focus beams of x rays or neutrons using the refractive properties of matter. In the case of neutrons, the refractive properties of magnetic induction can similarly focus and simultaneously polarize the neutron beam without the concomitant attenuation of matter. This concept of a magnetic refractive lens was tested using a compound lens consisting of 99 pairs of cylindrical permanent magnets. The assembly successfully focused the intensity of a white beam of cold neutrons of one spin state at the detector, while defocusing the other. This experiment confirmed that a lens of this nature may boost the intensity locally by almost an order of magnitude and create a polarized beam. An estimate of the performance of a more practically dimensioned device suitable for incorporation in reflectometers and slit-geometry small angle scattering instruments is given

  9. Magnetic compound refractive lens for focusing and polarizing cold neutron beams.

    Science.gov (United States)

    Littrell, K C; te Velthuis, S G E; Felcher, G P; Park, S; Kirby, B J; Fitzsimmons, M R

    2007-03-01

    Biconcave cylindrical lenses are used to focus beams of x rays or neutrons using the refractive properties of matter. In the case of neutrons, the refractive properties of magnetic induction can similarly focus and simultaneously polarize the neutron beam without the concomitant attenuation of matter. This concept of a magnetic refractive lens was tested using a compound lens consisting of 99 pairs of cylindrical permanent magnets. The assembly successfully focused the intensity of a white beam of cold neutrons of one spin state at the detector, while defocusing the other. This experiment confirmed that a lens of this nature may boost the intensity locally by almost an order of magnitude and create a polarized beam. An estimate of the performance of a more practically dimensioned device suitable for incorporation in reflectometers and slit-geometry small angle scattering instruments is given.

  10. Poster - 25: Neutron Spectral Measurements around a Scanning Proton Beam

    Energy Technology Data Exchange (ETDEWEB)

    Kildea, John; Enger, Shirin; Maglieri, Robert; Mirzakhanian, Lalageh; Dahlgren, Christina Vallhagen; Dubeau, Jacques; Witharana, Sanjeeva [Medical Physics Unit, McGill University Health Centre, Medical Physics Unit, McGill University, Medical Physics Unit, McGill University, Medical Physics Unit, McGill University, Skandion Clinic, Detec Inc., Gatineau, Quebec, Detec Inc., Gatineau, Quebec (Canada)

    2016-08-15

    We describe the measurements of neutron spectra that we undertook around a scanning proton beam at the Skandion proton therapy clinic in Uppsala, Sweden. Measurements were undertaken using an extended energy range Nested Neutron Spectrometer (NNS, Detec Inc., Gatineau, QC) operated in pulsed and current mode. Spectra were measured as a function of location in the treatment room and for various Bragg peak depths. Our preliminary unfolded data clearly show the direct, evaporation and thermal neutron peaks and we can show the effect on the neutron spectrum of a water phantom in the primary proton beam.

  11. Simulation study of accelerator based quasi-mono-energetic epithermal neutron beams for BNCT.

    Science.gov (United States)

    Adib, M; Habib, N; Bashter, I I; El-Mesiry, M S; Mansy, M S

    2016-01-01

    Filtered neutron techniques were applied to produce quasi-mono-energetic neutron beams in the energy range of 1.5-7.5 keV at the accelerator port using the generated neutron spectrum from a Li (p, n) Be reaction. A simulation study was performed to characterize the filter components and transmitted beam lines. The feature of the filtered beams is detailed in terms of optimal thickness of the primary and additive components. A computer code named "QMNB-AS" was developed to carry out the required calculations. The filtered neutron beams had high purity and intensity with low contamination from the accompanying thermal, fast neutrons and γ-rays. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Utilization of cold neutron beams at intermediate flux reactors

    International Nuclear Information System (INIS)

    Clark, D.D.

    1992-01-01

    With the advent of cold neutron beam (CNB) facilities at U.S. reactors [National Institute of Standards and Technology (NIST) in 1991; Cornell University and the University of Texas at Austin, anticipated in 1992], it is appropriate to reexamine the types of research for which they are likely to be best suited or uniquely suited. With the exception of a small-angle neutron scattering facility at Brookhaven National Laboratory, there has been no prior experience in the United States with such beams, but they have been extensively used at European reactors where cold neutron sources and neutron guides were developed some years age. This paper does not discuss specialized cases such as ultracold neutrons or very high flux facilities such as the Institute Laue-Langevin ractor and the proposed advanced neutron source. Instead, it concentrates on potential utilization of CNBs at intermediate-flux reactors such as at Cornell and Texas, i.e., in the 1-MW range and operated <24 h a day

  13. Status report of the program on neutron beam utilization at the Dalat Nuclear Research Reactor

    International Nuclear Information System (INIS)

    Vuong Huu Tan

    1996-08-01

    The thermal reactor is an intense source not only of thermal neutron, but also intermediate as well as fast neutrons. Using the filtered neutron beam technique at steady state atomic reactor allows receiving the neutrons in the intermediate energy region with the most available intense flux at present. In the near time at the Dalat reactor the filtered neutron beam technique has been applied. Utilization of the filtered neutron beams in basic and applied researches has been a important activity of the Dalat Nuclear Research Institute (DNRI). This report presents some relevant characteristics of the filtered neutron beams and their utilization in nuclear data measurements, neutron capture gamma ray spectroscopy, neutron radiography, neutron dose calibration and other applications. (author). 3 refs, 2 figs

  14. Characteristic analysis on moderating material for obtaining epithermal neutron beam

    International Nuclear Information System (INIS)

    Jiang Xinbiao; Chen Da; Zhang Ying

    2000-01-01

    The one dimension discrete coordinates transport code ANISN was used to calculate three-group constants of 11 elements which could be used to consist moderating epithermal neutron material of beam. Moderating character of simple substances, compounds and mixtures consisted of the optimized elements analyzed three kinds of moderating materials were optimized for epithermal neutron beam

  15. Consequences of trapped beam ions of the analysis of neutron emission data

    International Nuclear Information System (INIS)

    Loughlin, M.J.; Hone, M.; Jarvis, O.N.; Laundy, B.; Sadler, G.; Belle, P. van

    1989-01-01

    Neutron energy spectra have been measured during D o neutral beam heating of deuterium plasmas. The thermonuclear to beam-plasma neutron production ratios are deduced. For a non-radial spectrometer line-of-sight, the trapped beam-ion fraction must be considered. (author) 5 refs., 4 figs

  16. Self-shielding for thick slabs in a converging neutron beam

    CERN Document Server

    Mildner, D F R

    1999-01-01

    We have previously given a correction to the neutron self-shielding for a thin slab to account for the increased average path length through the slab when irradiated in a converging neutron beam. This expression overstates the case for the self-shielding for a thick (or highly absorbing) slab. We give a better approximation to the increase in effective shielding correction for a slab placed in a converging neutron beam. It is negligible at large absorption mean free paths. (author)

  17. Monochromatic neutron beam production at Brazilian nuclear research reactors

    Science.gov (United States)

    Stasiulevicius, Roberto; Rodrigues, Claudio; Parente, Carlos B. R.; Voi, Dante L.; Rogers, John D.

    2000-12-01

    Monochomatic beams of neutrons are obtained form a nuclear reactor polychromatic beam by the diffraction process, suing a single crystal energy selector. In Brazil, two nuclear research reactors, the swimming pool model IEA-R1 and the Argonaut type IEN-R1 have been used to carry out measurements with this technique. Neutron spectra have been measured using crystal spectrometers installed on the main beam lines of each reactor. The performance of conventional- artificial and natural selected crystals has been verified by the multipurpose neutron diffractometers installed at IEA-R1 and simple crystal spectrometer in operator at IEN- R1. A practical figure of merit formula was introduced to evaluate the performance and relative reflectivity of the selected planes of a single crystal. The total of 16 natural crystals were selected for use in the neutron monochromator, including a total of 24 families of planes. Twelve of these natural crystal types and respective best family of planes were measured directly with the multipurpose neutron diffractometers. The neutron spectrometer installed at IEN- R1 was used to confirm test results of the better specimens. The usually conventional-artificial crystal spacing distance range is limited to 3.4 angstrom. The interplane distance range has now been increased to approximately 10 angstrom by use of naturally occurring crystals. The neutron diffraction technique with conventional and natural crystals for energy selection and filtering can be utilized to obtain monochromatic sub and thermal neutrons with energies in the range of 0.001 to 10 eV. The thermal neutron is considered a good tool or probe for general applications in various fields, such as condensed matter, chemistry, biology, industrial applications and others.

  18. RBEs and cytogenetic hereditary effects induced by neutron beams in mice

    International Nuclear Information System (INIS)

    Du Zeji; Li Yanyi; Liu Degui

    1994-01-01

    The RBEs and cytogenetic hereditary effects of different dose of neutron beams on chromosome aberrations and micronuclei of bone marrow cells in mice were observed. The results indicated that micronuclei frequency of occurrence and chromosome aberration frequency caused by neutrons increased with doses. The relationship was feasible to Y aD n . The lower energy of neutrons had the smaller value of RBE. RBE determined by CSACR were larger than that by MNCF. RBEs decreased with increasing of neutron doses, especially within the low range of doses. There was a linear relationship between CSACR and MNCF caused by neutron beams and γ-ray

  19. OPTIMIZATION OF THE EPITHERMAL NEUTRON BEAM FOR BORON NEUTRON CAPTURE THERAPY AT THE BROOKHAVEN MEDICAL RESEARCH REACTOR.

    Energy Technology Data Exchange (ETDEWEB)

    HU,J.P.; RORER,D.C.; RECINIELLO,R.N.; HOLDEN,N.E.

    2002-08-18

    Clinical trials of Boron Neutron Capture Therapy for patients with malignant brain tumor had been carried out for half a decade, using an epithermal neutron beam at the Brookhaven's Medical Reactor. The decision to permanently close this reactor in 2000 cut short the efforts to implement a new conceptual design to optimize this beam in preparation for use with possible new protocols. Details of the conceptual design to produce a higher intensity, more forward-directed neutron beam with less contamination from gamma rays, fast and thermal neutrons are presented here for their potential applicability to other reactor facilities. Monte Carlo calculations were used to predict the flux and absorbed dose produced by the proposed design. The results were benchmarked by the dose rate and flux measurements taken at the facility then in use.

  20. Application of Zeeman spatial beam-splitting in polarized neutron reflectometry

    OpenAIRE

    Kozhevnikov, S. V.; Ignatovich, V. K.; Radu, F.

    2017-01-01

    Neutron Zeeman spatial beam-splitting is considered at reflection from magnetically noncollinear films. Two applications of Zeeman beam-splitting phenomenon in polarized neutron reflectometry are discussed. One is the construction of polarizing devices with high polarizing efficiency. Another one is the investigations of magnetically noncollinear films with low spin-flip probability. Experimental results are presented for illustration.

  1. Epithermal neutron beam adoption for lung and pancreatic cancer treatment by boron neutron capture therapy

    International Nuclear Information System (INIS)

    Matsumoto, Tetsuo; Fukushima, Yuji

    2001-01-01

    The depth-dose distributions were evaluated for possible treatment of both lung and pancreatic cancers using an epithermal neutron beam. The Monte Carlo Neutron Photon (MCNP) calculations showed that physical dose in tumors were 6 and 7 Gy/h, respectively, for lung and pancreas, attaining an epithermal neutron flux of 5 x 10 8 ncm -2 s -1 . The boron concentrations were assumed at 100 ppm and 30 ppm, respectively, for lung and pancreas tumors and normal tissues contains 1/10 tumor concentrations. The dose ratios of tumor to normal tissue were 2.5 and 2.4, respectively, for lung and pancreas. The dose evaluation suggests that BNCT using an epithermal neutron beam could be applied for both lung and pancreatic cancer treatment. (author)

  2. Geant4 simulations of NIST beam neutron lifetime experiment

    Science.gov (United States)

    Valete, Daniel; Crawford, Bret; BL2 Collaboration Collaboration

    2017-09-01

    A free neutron is unstable and its decay is described by the Standard Model as the transformation of a down quark into an up quark through the weak interaction. Precise measurements of the neutron lifetime test the validity of the theory of the weak interaction and provide useful information for the predictions of the theory of Big Bang nucleosynthesis of the primordial helium abundance in the universe and the number of different types of light neutrinos Nν. The predominant experimental methods for determination of the neutron lifetime are commonly called `beam' and `bottle' methods, and the most recent uses of each method do not agree with each other within their stated uncertainties. An improved experiment of the beam technique, which uses magnetic and electric fields to trap and guide the decay protons of a beam of cold neutrons to a detector, is in progress at the National Institute of Standards and Technology, Gaithersburg, MD with a precision goal of 0.1. I acknowledge the support of the Cross-Diciplinary Institute at Gettysburg College.

  3. Feasibility Analysis for the Construction of Vertical Neutron Beam in the MNSR

    International Nuclear Information System (INIS)

    Al-Ayoubi, S.; Sulaiman, I.

    2009-06-01

    The MCNP-4C code was used to investigate the possibility of extracting a vertical neutron beam in the MNSR reactor. Code results showed that thermal neutron flux at the exit aperture of about ( 6 x10 5 ) cm -2 s -1 could be obtained and neutron beam properties were determined. (author)

  4. Design considerations for primary neutron beam collimation on the Spallation Neutron Source

    International Nuclear Information System (INIS)

    Howells, W.S.

    1980-09-01

    A scheme for the design of primary neutron beam collimation is presented which is based on ray diagrams. The practical application of the ideas is outlined and the influence of various constraints such as beam shutters is discussed. The ideas are illustrated with examples which include the layouts for some typical instruments. (author)

  5. Conventional external beam radiotherapy for central nervous system malignancies

    International Nuclear Information System (INIS)

    Halperin, E.C.; Burger, P.C.

    1985-01-01

    Fractionated external beam photon radiotherapy is an important component of the clinical management of malignant disease of the central nervous system. The practicing neurologist or neurosurgeon frequently relies on the consultative and treatment skills of a radiotherapist. This article provides a review for the nonradiotherapist of the place of conventional external beam radiotherapy in neuro-oncology. 23 references

  6. Investigations of the neutron halo by radioactive beam experiments

    International Nuclear Information System (INIS)

    Mueller, A.C.

    1993-01-01

    Recently, a new tool has become available to study the behaviour of nuclei at the limits of particle stability. Heavy-ion projectile fragmentation, in combination with efficient recoil spectrometers, allows to prepare 'exotic' beams which can be used to induce secondary nuclear reactions. First experiments have revealed surprising features in the reactions of the most neutron-rich light nuclei. There is now conclusive evidence that the observed effects are due to long-tail matter distributions ('neutron halo') which occur for the last, very weakly bound neutrons. The results of some recent radioactive beam experiments, made by means of the spectrometer LISE3 at GANIL, are presented. (author) 24 refs.; 7 figs

  7. Prompt-gamma spectrometry for the optimization of reactor neutron beams in biomedical research

    International Nuclear Information System (INIS)

    Borisov, G.I.; Komkov, M.M.; Leonov, V.F.

    1988-01-01

    In order to select the optimal spectral composition and size for the reactor neutron beams applied to in vivo analysis and therapy in biomedical research it is necessary to determine the spatial slow-neutron flux distributions produced by the beam in the irradiated object and to calculate or measure the neutron dose equivalents of both the original spectrum and the moderated neutrons. In this study the maximum neutron dose equivalents are found by spectrometry of the prompt-γ emission from the interaction of neutrons with atomic nuclei in the irradiated object. Different spectral distributions were produced by using an unfiltered beam together with filters of quartz, cadmium, 10 B, iron, aluminum, and sulfur. The phantom used was a tank filled with an aqueous solution of urea. Cadmium-containing organs were simulated. For in vivo neutron-activation analysis of human tissues at a depth of 2-5 cm it was found advisable to use neutrons of 20-40 keV mean energy with a beam area of at least 45 cm 2

  8. A Kinematically Beamed, Low Energy Pulsed Neutron Source for Active Interrogation

    International Nuclear Information System (INIS)

    Dietrich, D.; Hagmann, C.; Kerr, P.; Nakae, L.; Rowland, M.; Snyderman, N.; Stoeffl, W.; Hamm, R.

    2004-01-01

    We are developing a new active interrogation system based on a kinematically focused low energy neutron beam. The key idea is that one of the defining characteristics of SNM (Special Nuclear Materials) is the ability for low energy or thermal neutrons to induce fission. Thus by using low energy neutrons for the interrogation source we can accomplish three goals, (1) Energy discrimination allows us to measure the prompt fast fission neutrons produced while the interrogation beam is on; (2) Neutrons with an energy of approximately 60 to 100 keV do not fission 238U and Thorium, but penetrate bulk material nearly as far as high energy neutrons do and (3) below about 100keV neutrons lose their energy by kinematical collisions rather than via the nuclear (n,2n) or (n,n') processes thus further simplifying the prompt neutron induced background. 60 keV neutrons create a low radiation dose and readily thermal capture in normal materials, thus providing a clean spectroscopic signature of the intervening materials. The kinematically beamed source also eliminates the need for heavy backward and sideway neutron shielding. We have designed and built a very compact pulsed neutron source, based on an RFQ proton accelerator and a lithium target. We are developing fast neutron detectors that are nearly insensitive to the ever-present thermal neutron and neutron capture induced gamma ray background. The detection of only a few high energy fission neutrons in time correlation with the linac pulse will be a clear indication of the presence of SNM

  9. A single-beam deuteron compact accelerator for neutron generation

    International Nuclear Information System (INIS)

    Araujo, Wagner Leite; Campos, Tarcisio Passos Ribeiro de

    2011-01-01

    Portable neutron generators are devices composed by small size accelerators that produce neutrons through fusion between hydrogen isotopes. These reactions are characterized by appreciable cross section at energies at the tens of keV, which enables device portability. The project baselines follow the same physical and engineering principles of any other particle accelerators. The generator consists of a gas reservoir, apparatus for ion production, few electrodes to accelerate and focus the ion beam, and a metal hydride target where fusion reactions occur. Neutron generator applications include geophysical measurements, indus- trial process control, environmental, research, nation's security and mechanical structure analysis.This article presents a design of a compact accelerator for d-d neutron generators, describing the physical theory applied to the deuteron extraction system, and simulating the ion beam transport in the accelerator. (author)

  10. Primary study for boron neutron capture therapy uses the RSG-GAS beam tube facility

    International Nuclear Information System (INIS)

    Suroso

    2000-01-01

    The minimum epithermal neutron flux as one of the prerequisite of Boron Neutron Capture Therapy (BNCT) is 1.0 x 10 9 n/(cm 2 s) RSG-GAS have 6 beam tube facilities for neutron source, which is one of the beam tube S-2 has a possibility to utilization for BNCT facility. The totally flux neutron measurement in the front of S-2 beam tube is 1.8 x 10 7 n/(cm 2 s). The neutron flux measurement was less than for BNCT minimum prerequisite. Concerning to the flux neutron production in the reactor, which is reach to 2.5 x 10 14 n/(cm 2 s), there for the S-2 beam tube could be used beside collimator modification

  11. Neutron beam-line shield design for the protein crystallography instrument at the Lujan Center

    International Nuclear Information System (INIS)

    Russell, G.J.; Pitcher, E.J.; Muhrer, G.; Ferguson, P.D.

    2001-01-01

    We have developed a very useful methodology for calculating absolute total (neutron plus gamma-ray) dose equivalent rates for use in the design of neutron beam line shields at a spallation neutron source. We have applied this technique to the design of beam line shields for several new materials science instruments being built at the Manuel Lujan Jr. Neutron Scattering Center. These instruments have a variety of collimation systems and different beam line shielding issues. We show here some specific beam line shield designs for the Protein Crystallography Instrument. (author)

  12. How to polarise all neutrons in one beam: a high performance polariser and neutron transport system

    Science.gov (United States)

    Rodriguez, D. Martin; Bentley, P. M.; Pappas, C.

    2016-09-01

    Polarised neutron beams are used in disciplines as diverse as magnetism,soft matter or biology. However, most of these applications often suffer from low flux also because the existing neutron polarising methods imply the filtering of one of the spin states, with a transmission of 50% at maximum. With the purpose of using all neutrons that are usually discarded, we propose a system that splits them according to their polarisation, flips them to match the spin direction, and then focuses them at the sample. Monte Carlo (MC) simulations show that this is achievable over a wide wavelength range and with an outstanding performance at the price of a more divergent neutron beam at the sample position.

  13. Role of external neutrons of weakly bound nuclei in reactions with their participation

    Science.gov (United States)

    Naumenko, M. A.; Penionzhkevich, Yu E.; Samarin, V. V.; Sobolev, Yu G.

    2018-05-01

    The paper presents the results of measurement of the total cross sections for reactions 4,6He+Si and 6,7,9Li+Si in the beam energy range 5–50 A MeV. The enhancements of the total cross sections for reaction 6He+Si compared with reaction 4He+Si and 9Li+Si compared with reactions 6,7Li+Si have been observed. The performed microscopic analysis of total cross sections for reactions 6He+Si and 9Li+Si based on numerical solution of the time-dependent Schrödinger equation for external neutrons of projectile nuclei 6He and 9Li yielded good agreement with experimental data.

  14. A standardized method for beam design in neutron capture therapy

    International Nuclear Information System (INIS)

    Storr, G.J.: Harrington, B.V.

    1993-01-01

    A desirable end point for a given beam design for Neutron Capture Therapy (NCT) should be quantitative description of tumour control probability and normal tissue damage. Achieving this goal will ultimately rely on data from NCT human clinical trials. Traditional descriptions of beam designs have used a variety of assessment methods to quantify proposed or installed beam designs. These methods include measurement and calculation of open-quotes free fieldclose quotes parameters, such as neutron and gamma flux intensities and energy spectra, and figures-of-merit in tissue equivalent phantoms. The authors propose here a standardized method for beam design in NCT. This method would allow all proposed and existing NCT beam facilities to be compared equally. The traditional approach to determining a quantitative description of tumour control probability and normal tissue damage in NCT research may be described by the following path: Beam design → dosimetry → macroscopic effects → microscopic effects. Methods exist that allow neutron and gamma fluxes and energy dependence to be calculated and measured to good accuracy. By using this information and intermediate dosimetric quantities such as kerma factors for neutrons and gammas, macroscopic effect (absorbed dose) in geometries of tissue or tissue-equivalent materials can be calculated. After this stage, for NCT the data begins to become more sparse and in some areas ambiguous. Uncertainties in the Relative Biological Effectiveness (RBE) of some NCT dose components means that beam designs based on assumptions considered valid a few years ago may have to be reassessed. A standard method is therefore useful for comparing different NCT facilities

  15. Novel neutralized-beam intense neutron source for fusion technology development

    International Nuclear Information System (INIS)

    Osher, J.E.; Perkins, L.J.

    1983-01-01

    We describe a neutralized-beam intense neutron source (NBINS) as a relevant application of fusion technology for the type of high-current ion sources and neutral beamlines now being developed for heating and fueling of magnetic-fusion-energy confinement systems. This near-term application would support parallel development of highly reliable steady-state higher-voltage neutral D 0 and T 0 beams and provide a relatively inexpensive source of fusion neutrons for materials testing at up to reactor-like wall conditions. Beam-target examples described incude a 50-A mixed D-T total (ions plus neutrals) space-charge-neutralized beam at 120 keV incident on a liquid Li drive-in target, or a 50-A T 0 + T + space-charge-neutralized beam incident on either a LiD or gas D 2 target with calculated 14-MeV neutron yields of 2 x 10 15 /s, 7 x 10 15 /s, or 1.6 x 10 16 /s, respectively. The severe local heat loading on the target surface is expected to limit the allowed beam focus and minimum target size to greater than or equal to 25 cm 2

  16. Neutron spectra in two beam ports of the TRIGA Mark III reactor

    International Nuclear Information System (INIS)

    Vega C, H. R.; Hernandez D, V. M.; Aguilar, F.; Paredes, L.; Rivera M, T.

    2013-10-01

    The neutron spectra have been measured in two beam ports, radial and tangential, of the TRIGA Mark III nuclear reactor from the National Institute of Nuclear Research. Measurements were carried out with the core with mixed fuel (Leu 8.5/20 and Flip Heu 8.5/70). Two reactor powers, 5 and 10 W, were used during neutron spectra measurements using a Bonner sphere spectrometer with a 6 Lil(Eu) scintillator and 2, 3, 5, 8, 10 and 12 inches-diameter high density polyethylene spheres. The neutron spectra were unfolded using the NSDUAZ unfolding code; from each spectrum the total neutron flux, the neutron mean energy and the neutron ambient dose equivalent dose were determined. Measured spectra show fission (E≥ 0.1 MeV), epithermal (from 0.4 eV up to 0.1 MeV) and thermal neutrons (E≤ 0.4 eV). For both reactor powers the spectra in the radial beam port have similar features which are different to the neutron spectrum characteristics in the tangential beam port. (Author)

  17. Neutron spectra in two beam ports of the TRIGA Mark III reactor

    Energy Technology Data Exchange (ETDEWEB)

    Vega C, H. R.; Hernandez D, V. M. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98060 Zacatecas (Mexico); Aguilar, F.; Paredes, L. [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Rivera M, T., E-mail: fermineutron@yahoo.com [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Unidad Legaria, Av. Legaria 694, 11500 Mexico D. F. (Mexico)

    2013-10-15

    The neutron spectra have been measured in two beam ports, radial and tangential, of the TRIGA Mark III nuclear reactor from the National Institute of Nuclear Research. Measurements were carried out with the core with mixed fuel (Leu 8.5/20 and Flip Heu 8.5/70). Two reactor powers, 5 and 10 W, were used during neutron spectra measurements using a Bonner sphere spectrometer with a {sup 6}Lil(Eu) scintillator and 2, 3, 5, 8, 10 and 12 inches-diameter high density polyethylene spheres. The neutron spectra were unfolded using the NSDUAZ unfolding code; from each spectrum the total neutron flux, the neutron mean energy and the neutron ambient dose equivalent dose were determined. Measured spectra show fission (E≥ 0.1 MeV), epithermal (from 0.4 eV up to 0.1 MeV) and thermal neutrons (E≤ 0.4 eV). For both reactor powers the spectra in the radial beam port have similar features which are different to the neutron spectrum characteristics in the tangential beam port. (Author)

  18. A compact neutron beam generator system designed for prompt gamma nuclear activation analysis.

    Science.gov (United States)

    Ghassoun, J; Mostacci, D

    2011-08-01

    In this work a compact system was designed for bulk sample analysis using the technique of PGNAA. The system consists of (252)Cf fission neutron source, a moderator/reflector/filter assembly, and a suitable enclosure to delimit the resulting neutron beam. The moderator/reflector/filter arrangement has been optimised to maximise the thermal neutron component useful for samples analysis with a suitably low level of beam contamination. The neutron beam delivered by this compact system is used to irradiate the sample and the prompt gamma rays produced by neutron reactions within the sample elements are detected by appropriate gamma rays detector. Neutron and gamma rays transport calculations have been performed using the Monte Carlo N-Particle transport code (MCNP5). 2010 Elsevier Ltd. All rights reserved.

  19. 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 ...

  20. Triga IPR-R1 neutron beam: increasing the thematic of applications in CDTN

    International Nuclear Information System (INIS)

    Sebastiao, Rita de C.O.; Rodrigues, Rogerio R.; Leal, Alexandre S.

    2007-01-01

    The neutron flux in a research reactor can be used in several applications such as the neutron activation analysis, the radioisotopes production, study of DNA and protein structures, doping of silicon and neutron radiography. The enhancement of the nuclear research reactor utilization with the introduction of new applications would be possible with the availability of a neutron beam and with the neutron energy spectra completely characterized. This work evaluates the use of TRIGA reactor of CDTN/CNEN as a source of neutron beam. The readiness of a neutron beam with appropriate intensity and energy spectrum would make possible the increasing of the thematic of applications and researches in this reactor. The main contribution to this theme is to evaluate the thermal and epithermal neutron flux in the vertical extractor of the TRIGA IPR-R1. The simulation was performed in this work using the MCNP code. (author)

  1. Neutron spectroscopy measurements and modeling of neutral beam heating fast ion dynamics

    International Nuclear Information System (INIS)

    Hellesen, C; Sunden, E Andersson; Conroy, S; Ericsson, G; Johnson, M Gatu; Hjalmarsson, A; Kaellne, J; Ronchi, E; Sjoestrand, H; Weiszflog, M; Albergante, M; Ballabio, L; Gorini, G; Tardocchi, M; Giacomelli, L; Jenkins, I; Voitsekhovitch, I

    2010-01-01

    The energy spectrum of the neutron emission from beam-target reactions in fusion plasmas at the Joint European Torus (JET) has been investigated. Different beam energies as well as injection angles were used. Both measurements and simulations of the energy spectrum were done. The measurements were made with the time-of-flight spectrometer TOFOR. Simulations of the neutron spectrum were based on first-principle calculations of neutral beam deposition profiles and the fast ion slowing down in the plasma using the code NUBEAM, which is a module of the TRANSP package. The shape of the neutron energy spectrum was seen to vary significantly depending on the energy of the beams as well as the injection angle and the deposition profile in the plasma. Cross validations of the measured and modeled neutron energy spectra were made, showing a good agreement for all investigated scenarios.

  2. Radiation transport calculations for the ANS [Advanced Neutron Source] beam tubes

    International Nuclear Information System (INIS)

    Engle, W.W. Jr.; Lillie, R.A.; Slater, C.O.

    1988-01-01

    The Advanced Neutron Source facility (ANS) will incorporate a large number of both radial and no-line-of-sight (NLS) beam tubes to provide very large thermal neutron fluxes to experimental facilities. The purpose of this work was to obtain comparisons for the ANS single- and split-core designs of the thermal and damage neutron and gamma-ray scalar fluxes in these beams tubes. For experimental locations far from the reactor cores, angular flux data are required; however, for close-in experimental locations, the scalar fluxes within each beam tube provide a credible estimate of the various signal to noise ratios. In this paper, the coupled two- and three-dimensional radiation transport calculations employed to estimate the scalar neutron and gamma-ray fluxes will be described and the results from these calculations will be discussed. 6 refs., 2 figs

  3. Fusion reaction using low energy neutron-excess nucleus beam

    International Nuclear Information System (INIS)

    Fukuda, Tomokazu

    1994-01-01

    The present state and the plan of the experiment of measuring the fusion reaction near barriers by using neutron-excess nucleus beam, which has been advanced at RIKEN are reported. One of the purposes of this experiment is the feasibility investigation of the fusion reaction by using neutron-excess nuclei, which is indispensable for synthesizing superheavy elements. It is intended to systematically explore some enhancing mechanism in the neutron-excess nuclei which are unfavorable in beam intensity. This research can become the good means to prove the dynamic behavior of the neutrons on the surfaces of nuclei in reaction. The fusion reaction of 27 Al + Au was measured by using the stable nucleus beam of 27 Al, and the results are shown. In order to know the low energy fusion reaction of 11 Li and 11 Be which are typical halo nuclei, the identification by characteristic α ray of composite nuclei is carried out in 7,9,11 Li + 209 Bi and 9,10,11 Be + 208 Pb. A new detector having high performance, New MUSIC, is being developed. As the experiment by using this detector, the efficient measurement of the fusion reaction by using heavy neutron-excess nuclei up to Ni is considered. An example of 8 Li + α → 11 B + n reaction for celestial body physics is mentioned. (K.I.)

  4. Flux distribution in phantom for biomedical use of beam-type thermal neutrons

    International Nuclear Information System (INIS)

    Aoki, Kazuhiko; Kobayashi, Tooru; Kanda, Keiji; Kimura, Itsuro

    1985-01-01

    For boron neutron capture therapy, the thermal neutron beam is worth using as therapeutic neutron irradiation without useless and unfavorable exposure of normal tissues around tumor and for microanalysis system to measure ppm-order 10 B concentrations in tissue and to search for the location of the metastasis of tumor. In the present study, the thermal neutron flux distribution in a phantom, when beam-type thermal neutrons were incident on it, was measured at the KUR Neutron Guide Tube. The measurements were carried out by two different methods using indium foil. The one is an ordinary foil activation technique by using the 115 In(n, γ) 116m 1 In reactions, while the other is to detect γ-rays from the 115 In(n, γ) 116m 2 In reactions during neutron irradiations with a handy-type Ge detector. The calculations with DOT 3.5 were performed to examine thermal neutron flux in the phantom for various beam size and phantom size. The experimental and calculated results are in good agreement and it is shown that the second type measurement has a potential for practical application as a new monitoring system of the thermal neutron flux in a living body for boron neutron capture therapy. (author)

  5. Experiments with neutron-rich isomeric beams

    International Nuclear Information System (INIS)

    Rykaczewski, K.; Lewitowicz, M.; Pfuetzner, M.

    1998-01-01

    A review of experimental results obtained on microsecond-isomeric states in neutron-rich nuclei produced in fragmentation reactions and studied with SISSI-Alpha-LISE3 spectrometer system at GANIL Caen is given. The perspectives of experiments based on secondary reactions with isomeric beams are presented

  6. Development of an external Faraday cup for beam current measurements

    International Nuclear Information System (INIS)

    Kim, Kye-Ryung; Jung, Myung-Hwan; Ra, Se-Jin; Lee, Seok-Ki

    2010-01-01

    In general, beam current measurements are very important for many kinds of experiments using highly energetic particle beams at accelerators, such as cyclotrons, linacs, etc. The Faraday cup is known to be one of the most popular beam current measurement tools. We developed an external Faraday cup to measure the beam current at a dedicated beam line for low-flux experiments installed at the MC-50 cyclotron of Korea Institute of Radiological and Medical Sciences (KIRAMS). It was designed for external beam current measurements and is composed of a vacuum chamber, an entrance window, a collimator, a electrostatic suppressor ring, and a cup. The window is made of 75-um-thick Kapton film, and the diameter of the collimator is 10 mm or 20 mm. The ring and the cup has 5-cm inner diameters, and the thickness of the bottom of the cup is 2 cm, which is enough to absorb the total proton energy up to 45 MeV. Using this external Faraday cup, we measured the beam current from the cyclotron, and we compared measured flux to the results from film dosimetry using GAF films.

  7. Comparison of radioimmunotherapy and external beam radiotherapy in colon cancer xenografts

    International Nuclear Information System (INIS)

    Buras, R.R.; Wong, J.F.C.; Kuhn, J.A.; Beatty, B.G.; Williams, L.E.; Beatty, J.D.; Wanek, P.M.

    1993-01-01

    Radioimmunotherapy and external beam radiotherapy were compared in a nude mouse human colon cancer model. Radioimmunotherapy was delivered by intraperitoneal injection of 90 Y-labeled anticarcinoembryonic antigen monoclonal antibody (anti-CEA MAB). Single fraction external beam radiotherapy was delivered using a 60 Co teletherapy unit. Control groups received saline, unlabeled anit-CEA monoclonal antibody and labeled nonspecific monoclonal antibody. Tumor growth suppression was expressed as delay to reach 2g compared to saline controls. Unlabeled anti-CEA monoclonal antibody and labeled nonspecific monoclonal antibody had no effect. External beam radiotherapy of 300, 600, 1000 and 2000 cGy produced growth delays of 3, 12, 17, and 22 days, respectively. Radioimmunotherapy with 120 μCi, 175 μCi, and 225 μCi resulted in growth delays of 20, 34, and 36 days. Estimated absorbed tumor dose was 1750 cGy in the 120 μCi group. Similar comparisons were done with the more radioresistant WiDr human colon carcinoma cell line. External beam radiotherapy doses of 400, 800, 1200, and 1600 cGy resulted in growth delays of 6, 21, 36 and 48 days, respectively. Radioimmunotherapy of 120 μCi and 175 μCi resulted in growth delays of 9 and 19 days, respectively. The 120 μCi dose delivered an estimated absorbed tumor dose of 1080 cGy to WiDr tumors. In summary, for the radiosensitive LS174T line, radioimmunotherapy produced biologic effects that were comparable to a similar dose of single fraction external beam radiotherapy. For the more radioresistant WiDr tumor, radioimmunotherapy produced a biologic effect which was less than a similar dose of single fraction external beam radiotherapy. These studies suggest that a tumor's response to radioimmunotherapy relative to that of external beam radiotherapy is, in part, dependent on tumor radiosensitivity and repair capacity. 23 refs., 5 figs. 4 tabs

  8. 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.

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

    International Nuclear Information System (INIS)

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

    1990-01-01

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

  10. Prediction of in-phantom dose distribution using in-air neutron beam characteristics for BNCS

    International Nuclear Information System (INIS)

    Verbeke, Jerome M.

    1999-01-01

    A monoenergetic neutron beam simulation study is carried out to determine the optimal neutron energy range for treatment of rheumatoid arthritis using radiation synovectomy. The goal of the treatment is the ablation of diseased synovial membranes in joints, such as knees and fingers. This study focuses on human knee joints. Two figures-of-merit are used to measure the neutron beam quality, the ratio of the synovium absorbed dose to the skin absorbed dose, and the ratio of the synovium absorbed dose to the bone absorbed dose. It was found that (a) thermal neutron beams are optimal for treatment, (b) similar absorbed dose rates and therapeutic ratios are obtained with monodirectional and isotropic neutron beams. Computation of the dose distribution in a human knee requires the simulation of particle transport from the neutron source to the knee phantom through the moderator. A method was developed to predict the dose distribution in a knee phantom from any neutron and photon beam spectra incident on the knee. This method was revealed to be reasonably accurate and enabled one to reduce by a factor of 10 the particle transport simulation time by modeling the moderator only

  11. Prediction of in-phantom dose distribution using in-air neutron beam characteristics for BNCS

    Energy Technology Data Exchange (ETDEWEB)

    Verbeke, Jerome M.

    1999-12-14

    A monoenergetic neutron beam simulation study is carried out to determine the optimal neutron energy range for treatment of rheumatoid arthritis using radiation synovectomy. The goal of the treatment is the ablation of diseased synovial membranes in joints, such as knees and fingers. This study focuses on human knee joints. Two figures-of-merit are used to measure the neutron beam quality, the ratio of the synovium absorbed dose to the skin absorbed dose, and the ratio of the synovium absorbed dose to the bone absorbed dose. It was found that (a) thermal neutron beams are optimal for treatment, (b) similar absorbed dose rates and therapeutic ratios are obtained with monodirectional and isotropic neutron beams. Computation of the dose distribution in a human knee requires the simulation of particle transport from the neutron source to the knee phantom through the moderator. A method was developed to predict the dose distribution in a knee phantom from any neutron and photon beam spectra incident on the knee. This method was revealed to be reasonably accurate and enabled one to reduce by a factor of 10 the particle transport simulation time by modeling the moderator only.

  12. Fast neutron detection at near-core location of a research reactor with a SiC detector

    Science.gov (United States)

    Wang, Lei; Jarrell, Josh; Xue, Sha; Tan, Chuting; Blue, Thomas; Cao, Lei R.

    2018-04-01

    The measurable charged-particle produced from the fast neutron interactions with the Si and C nucleuses can make a wide bandgap silicon carbide (SiC) sensor intrinsically sensitive to neutrons. The 4H-SiC Schottky detectors have been fabricated and tested at up to 500 °C, presenting only a slightly degraded energy resolution. The response spectrum of the SiC detectors were also obtained by exposing the detectors to external neutron beam irradiation and at a near-core location where gamma-ray field is intense. The fast neutron flux of these two locations are ∼ 4 . 8 × 104cm-2 ṡs-1 and ∼ 2 . 2 × 107cm-2 ṡs-1, respectively. At the external beam location, a Si detector was irradiated side-by-side with SiC detector to disjoin the neutron response from Si atoms. The contribution of gamma ray, neutron scattering, and charged-particles producing reactions in the SiC was discussed. The fast neutron detection efficiencies were determined to be 6 . 43 × 10-4 for the external fast neutron beam irradiation and 6 . 13 × 10-6 for the near-core fast neutron irradiation.

  13. Precise determination of the degree of polarization of a cold neutron beam

    International Nuclear Information System (INIS)

    Nastoll, H.; Schreckenbach, K.; Baglin, C.; Bussiere, A.; Guillaud, J.P.; Kossakowski, R.; Liaud, P.

    1991-01-01

    A cold neutron beam at the ILL High Flux Reactor was used to produce highly polarized neutrons by means of a bent supermirror polarizer. A following current sheet spin flipper allowed the change of the neutron spin direction relative to the guiding magnetic fields. The degree of polarization of the beam was measured as a function of the neutron velocity in the range 300-1500 m/s achieving an accuracy of 0.2% at typically 98% polarization. Two spin flippers and the permutation of three supermirror polarizers as polarizer/analyzer were employed. (orig.)

  14. Beam-transport optimization for cold-neutron spectrometer

    Directory of Open Access Journals (Sweden)

    Nakajima Kenji

    2015-01-01

    Full Text Available We report the design of the beam-transport system (especially the vertical geometry for a cold-neutron disk-chopper spectrometer AMATERAS at J-PARC. Based on the elliptical shape, which is one of the most effective geometries for a ballistic mirror, the design was optimized to obtain, at the sample position, a neutron beam with high flux without serious degrading in divergence and spacial homogeneity within the boundary conditions required from actual spectrometer construction. The optimum focal point was examined. An ideal elliptical shape was modified to reduce its height without serious loss of transmission. The final result was adapted to the construction requirements of AMATERAS. Although the ideas studied in this paper are considered for the AMATERAS case, they can be useful also to other spectrometers in similar situations.

  15. Beam monitoring system for intense neutron source

    International Nuclear Information System (INIS)

    Tron, A.M.

    2001-01-01

    Monitoring system realizing novel principle of operation and allowing to register a two-dimensional beam current distribution within entire aperture (100...200 mm) of ion pipe for a time in nanosecond range has been designed and accomplished for beam control of the INR intense neutron source, for preventing thermo-mechanical damage of its first wall. Key unit of the system is monitor of two-dimensional beam current distribution, elements of which are high resistant to heating by the beam and to radiation off the source. The description of the system and monitor are presented. Implementation of the system for the future sources with more high intensities are discussed. (author)

  16. Compendium of Neutron Beam Facilities for High Precision Nuclear Data Measurements

    International Nuclear Information System (INIS)

    2014-07-01

    The recent advances in the development of nuclear science and technology, demonstrating the globally growing economy, require highly accurate, powerful simulations and precise analysis of the experimental results. Confidence in these results is still determined by the accuracy of the atomic and nuclear input data. For studying material response, neutron beams produced from accelerators and research reactors in broad energy spectra are reliable and indispensable tools to obtain high accuracy experimental results for neutron induced reactions. The IAEA supports the accomplishment of high precision nuclear data using nuclear facilities in particular, based on particle accelerators and research reactors around the world. Such data are essential for numerous applications in various industries and research institutions, including the safety and economical operation of nuclear power plants, future fusion reactors, nuclear medicine and non-destructive testing technologies. The IAEA organized and coordinated the technical meeting Use of Neutron Beams for High Precision Nuclear Data Measurements, in Budapest, Hungary, 10–14 December 2012. The meeting was attended by participants from 25 Member States and three international organizations — the European Organization for Nuclear Research (CERN), the Joint Research Centre (JRC) and the Organisation for Economic Co-operation and Development (OECD) Nuclear Energy Agency (OECD/NEA). The objectives of the meeting were to provide a forum to exchange existing know-how and to share the practical experiences of neutron beam facilities and associated instrumentation, with regard to the measurement of high precision nuclear data using both accelerators and research reactors. Furthermore, the present status and future developments of worldwide accelerator and research reactor based neutron beam facilities were discussed. This publication is a summary of the technical meeting and additional materials supplied by the international

  17. Novel optics for conditioning neutron beams. II Focussing neutrons with a 'lobster-eye' optic

    International Nuclear Information System (INIS)

    Allman, B.E.; Cimmino, A.; Griffin, S.L.; Klein, A.G.; Nugent, K.A.

    1998-01-01

    Square-channel capillary, or 'Lobster-eye' arrays have been shown to be the optimum geometry for array optics. This configuration leads to a novel class of conditioning devices for X-ray and neutron beams. We present the first results of the focussing of neutrons with a Pb glass square-channel array. (authors)

  18. Evaluation of JRR-4 neutron beam using tumor cells

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Kazuyoshi; Kumada, Hiroaki; Torii, Yoshiya; Kishi, Toshiaki; Horiguchi, Yoji [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Yamamoto, Tetsuya; Matsumura, Akira; Nose, Tadao [Tsukuba Univ., Ibaraki (Japan)

    2001-03-01

    For preparation of irradiation plan of boron-neutron capture therapy (BNCT), not only the physical dose is important, but also weighted factors or RBE are also necessary on the evaluation of the effect on the organism. Physical dose calculated by dose evaluation system (JCDS : JAERI Computational Dosimetry System) must appropriately carry out the weighting by various cells like tumor, central nerve, glia, and the vascular in proportion to JRR-4 each irradiation mode. In-vitro biological experiment which used 9L gliosarcoma and C6 glioma in the head water phantom was carried out in order to evaluate these effect. Neutron beam characteristics of JRR-4 were also evaluated from the functions of survival fraction of these cells. As a result of the evaluation, it became clear that the dose evaluation calculated from physical dose of the boron and nitrogen carried out in traditional BNCT of Japan using thermal neutron is applicable for thermal and epi-thermal mixed neutron beam. (author)

  19. Radiative capture of cold neutrons by protons and deuteron photodisintegration with twisted beams

    Science.gov (United States)

    Afanasev, Andrei; Serbo, Valeriy G.; Solyanik, Maria

    2018-05-01

    We consider two basic nuclear reactions: capture of neutrons by protons, n + p → γ + d, and its time-reversed counterpart, photodisintegration of the deuteron, γ + d → n + p. In both of these cases we assume that the incoming beam of neutrons or photons is ‘twisted’ by having an azimuthal phase dependence, i.e., it carries an additional angular momentum along its direction of propagation. Taking a low-energy limit of these reactions, we derive relations between corresponding transition amplitudes and cross sections with plane-wave beams and twisted beams. Implications for experiments with twisted cold neutrons and twisted photon beams are discussed.

  20. High flux, beamed neutron sources employing deuteron-rich ion beams from D2O-ice layered targets

    Science.gov (United States)

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

    2017-06-01

    A forwardly-peaked bright neutron source was produced using a laser-driven, deuteron-rich ion beam in a pitcher-catcher scenario. A proton-free ion source was produced via target normal sheath acceleration from Au foils having a thin layer of D2O ice at the rear side, irradiated by sub-petawatt laser pulses (˜200 J, ˜750 fs) at peak intensity ˜ 2× {10}20 {{W}} {{cm}}-2. The neutrons were preferentially produced in a beam of ˜70° FWHM cone along the ion beam forward direction, with maximum energy up to ˜40 MeV and a peak flux along the axis ˜ 2× {10}9 {{n}} {{sr}}-1 for neutron energy above 2.5 MeV. The experimental data is in good agreement with the simulations carried out for the d(d,n)3He reaction using the deuteron beam produced by the ice-layered target.

  1. Beamed neutron emission driven by laser accelerated light ions

    Science.gov (United States)

    Kar, S.; Green, A.; Ahmed, H.; Alejo, A.; Robinson, A. P. L.; Cerchez, M.; Clarke, R.; Doria, D.; Dorkings, S.; Fernandez, J.; Mirfayzi, S. R.; McKenna, P.; Naughton, K.; Neely, D.; Norreys, P.; Peth, C.; Powell, H.; Ruiz, J. A.; Swain, J.; Willi, O.; Borghesi, M.

    2016-05-01

    Highly anisotropic, beam-like neutron emission with peak flux of the order of 109 n/sr was obtained from light nuclei reactions in a pitcher-catcher scenario, by employing MeV ions driven by a sub-petawatt laser. The spatial profile of the neutron beam, fully captured for the first time by employing a CR39 nuclear track detector, shows a FWHM divergence angle of ˜ 70^\\circ , with a peak flux nearly an order of magnitude higher than the isotropic component elsewhere. The observed beamed flux of neutrons is highly favourable for a wide range of applications, and indeed for further transport and moderation to thermal energies. A systematic study employing various combinations of pitcher-catcher materials indicates the dominant reactions being d(p, n+p)1H and d(d,n)3He. Albeit insufficient cross-section data are available for modelling, the observed anisotropy in the neutrons’ spatial and spectral profiles is most likely related to the directionality and high energy of the projectile ions.

  2. Neutron spectra in two beam ports of a TRIGA Mark III reactor with HEU fuel

    International Nuclear Information System (INIS)

    Vega C, H. R.; Hernandez D, V. M.; Paredes G, L.; Aguilar, F.

    2012-10-01

    Before to change the HEU for Leu fuel of the ININ's TRIGA Mark III nuclear reactor the neutron spectra were measured in two beam ports using 5 and 10 W. Measurements were carried out in a tangential and a radial beam port using a Bonner sphere spectrometer. It was found that neutron spectra are different in the beam ports, in radial beam port the amplitude of thermal and fast neutrons are approximately the same while, in the tangential beam port thermal neutron peak is dominant. In the radial beam port the fluence-to-ambient dose equivalent factors are 131±11 and 124±10 p Sv-cm 2 for 5 and 10 W respectively while in the tangential beam port the fluence-to-ambient dose equivalent factor is 55±4 p Sv-cm 2 for 10 W. (Author)

  3. Minimal requirements for quality controls in radiotherapy with external beams

    International Nuclear Information System (INIS)

    1999-01-01

    Physical dosimetric guidelines have been developed by the Italian National Institute of Health study group on quality assurance in radiotherapy to define protocols for quality controls in external beam radiotherapy. While the document does not determine strict rules or firm recommendations, it suggests minimal requirements for quality controls necessary to guarantee an adequate degree of accuracy in external beam radiotherapy [it

  4. Steel research using neutron beam techniques. In-situ neutron diffraction, small-angle neutron scattering and residual stress analysis

    International Nuclear Information System (INIS)

    Sueyoshi, Hitoshi; Ishikawa, Nobuyuki; Yamada, Katsumi; Sato, Kaoru; Nakagaito, Tatsuya; Matsuda, Hiroshi; Arakaki, Yu; Tomota, Yo

    2014-01-01

    Recently, the neutron beam techniques have been applied for steel researches and industrial applications. In particular, the neutron diffraction is a powerful non-destructive method that can analyze phase transformation and residual stress inside the steel. The small-angle neutron scattering is also an effective method for the quantitative evaluation of microstructures inside the steel. In this study, in-situ neutron diffraction measurements during tensile test and heat treatment were conducted in order to investigate the deformation and transformation behaviors of TRIP steels. The small-angle neutron scattering measurements of TRIP steels were also conducted. Then, the neutron diffraction analysis was conducted on the high strength steel weld joint in order to investigate the effect of the residual stress distribution on the weld cracking. (author)

  5. Beam Instrumentation for the Spallation Neutron Source Ring

    International Nuclear Information System (INIS)

    Witkover, R. L.; Cameron, P. R.; Shea, T. J.; Connolly, R. C.; Kesselman, M.

    1999-01-01

    The Spallation Neutron Source (SNS) will be constructed by a multi-laboratory collaboration with BNL responsible for the transfer lines and ring. The 1 MW beam power necessitates careful monitoring to minimize un-controlled loss. This high beam power will influence the design of the monitors in the high energy beam transport line (HEBT) from linac to ring, in the ring, and in the ring-to-target transfer line (RTBT). The ring instrumentation must cover a 3-decade range of beam intensity during accumulation. Beam loss monitoring will be especially critical since un-controlled beam loss must be kept below 10 -4 . A Beam-In-Gap (BIG) monitor is being designed to assure out-of-bucket beam will not be lost in the ring

  6. Other applications of neutron beams in material sciences; Autres utilisations des faisceaux de neutrons en science des materiaux

    Energy Technology Data Exchange (ETDEWEB)

    Novion, C.H. de

    1997-12-31

    The various applications of neutron beams are reviewed. The different mechanisms involved in neutron interaction with matter are explained. We notice that generally neutron radiation effects are unfavorable but can be turned into efficient tools to add new structures or properties to materials, silicon doping is an example. The basis principles of neutron activation analysis and neutron radiography are described. (A.C.)

  7. Generation of neutron standing waves at total reflection of polarized neutrons

    International Nuclear Information System (INIS)

    Aksenov, V.L.; Nikitenko, Yu.V.; Kozhevnikov, S.V.; Radu, F.; Kruijs, R.; Rekveldt, M.Th.

    1999-01-01

    The regime of neutron standing waves at reflection of polarized thermal neutrons from the structure glass/Cu (1000 A Angstrom)/Ti (2000 A Angstrom)/Co (60 A Angstrom)/Ti (300 A Angstrom) in a magnetic field directed at an angle to the sample plane is realized. The intensity of neutrons with a particular spin projection on the external magnetic field direction appears to be a periodic function of the neutron wavelength and the glancing angle of the reflected beam. It is shown that the neutron standing wave regime can be a very sensitive method for the determination of changes in the spatial position of magnetic noncollinear layers. (author)

  8. Neutron capture studies of {sup 206}Pb at a cold neutron beam

    Energy Technology Data Exchange (ETDEWEB)

    Schillebeeckx, P.; Kopecky, S.; Quetel, C.R.; Tresl, I.; Wynants, R. [Institute for Reference Materials and Measurements, European Commission, Joint Research Centre, Geel (Belgium); Belgya, T.; Szentmiklosi, L. [Institute for Energy Security and Environmental Safety, Centre for Energy Research, Budapest (Hungary); Borella, A. [Institute for Reference Materials and Measurements, European Commission, Joint Research Centre, Geel (Belgium); SCK CEN, Mol (Belgium); Mengoni, A. [Nuclear Data Section, International Atomic Energy Agency (IAEA), Wagramerstrasse 5, PO Box 100, Vienna (Austria); Agenzia Nazionale per le Nuove Tecnologie, l' Energia e lo Sviluppo Economico Sostenibile (ENEA), Bologna (Italy)

    2013-11-15

    Gamma-ray transitions following neutron capture in {sup 206}Pb have been studied at the cold neutron beam facility of the Budapest Neutron Centre using a metallic sample enriched in {sup 206}Pb and a natural lead nitrate powder pellet. The measurements were performed using a coaxial HPGe detector with Compton suppression. The observed {gamma} -rays have been incorporated into a decay scheme for neutron capture in {sup 206}Pb. Partial capture cross sections for {sup 206}Pb(n, {gamma}) at thermal energy have been derived relative to the cross section for the 1884 keV transition after neutron capture in {sup 14}N. From the average crossing sum a total thermal neutron capture cross section of 29{sup +2}{sub -1} mb was derived for the {sup 206}Pb(n, {gamma}) reaction. The thermal neutron capture cross section for {sup 206}Pb has been compared with contributions due to both direct capture and distant unbound s-wave resonances. From the same measurements a thermal neutron-induced capture cross section of (649 {+-} 14) mb was determined for the {sup 207}Pb(n, {gamma}) reaction. (orig.)

  9. Progress in neutron beam development at the HFR Petten (feasibility study for a BNCT facility)

    International Nuclear Information System (INIS)

    Constantine, G.; Moss, R.L.; Watkins, P.R.D.; Perks, C.A.; Delafield, H.J.; Ross, D.; Voorbraak, W.P.; Paardekooper, A.; Freudenreich, W.E.; Stecher-Rasmussen, F.

    1990-08-01

    Boron Neutron Capture Therapy, using intermediate energy neutrons to achieve the deep penetration essential for treating brain tumours, can be implemented with a filtered reactor neutron beam. This is designed to minimize the mean energy of the neutrons to keep proton recoil damage to the scalp within normal tissue tolerance limits whilst delivering the required thermal neutron fluence to the tumour over a reasonably short period. This can only be realized in conjunction with a high power density reactor. At the Joint Research Centre Petten an optimized neutron filter is currently being built for installation into the HB11 beam tube of the High Flux Reactor HFR. Part of the development leading to this design has been an extensive study of broad spectrum, filtered beam performance on the HB7 beam tube facility. A wide range of calculations was performed using the Monte Carlo code, MCPN, supported by validation experiments in which several filter configuration incorporating aluminium, sulphur, liquid argon, titanium and cadmium were installed for low power measurements of the neutron fluence rate, neutron spectra and beam gamma-ray contamination. The measurements were carried out within a successful European collaboration. Evaluations were made of the reactor core edge and unfiltered beam spectra, for comparison with MCNP calculations. Multi-foil activation methods and also gamma dose determination in the filtered beam using thermo-luminescent detectors were performed by the ECN. The Harwell/ Birmingham University collaborators undertook the neutron spectrum measurements in the filtered beam. proton recoil spectrometry was used above 30 keV, combined with a multi-sphere and BF 3 chamber response modification technique. Subsequent spectrum adjustment was carried out with the SENSAK code. The agreement between the calculated and measured spectra has given confidence in the reactor and filter modelling methods used to design the HB11 therapy facility. (author). 12 refs

  10. Characterisation of neutron beam and gamma spectrometer for PGAA

    International Nuclear Information System (INIS)

    Revay, Zs.; Molnar, G.L.

    2001-01-01

    In the second project year great efforts have been devoted in Budapest to the development of methods and procedures for neutron beam characterisation and spectrometer calibration. These are described here to provide recipes for other laboratories. Some illustrative results obtained on the former thermal guide, and partly on the new cold neutron guide are also given. Preliminary results from the benchmark experiments on flux monitors titanium standard and an unknown sample are also reported. New k o factors for elements of highest priority will be measured on the cold beam only in the near future. (author)

  11. A novel methodology to determine the divergence of a neutron beam

    Energy Technology Data Exchange (ETDEWEB)

    Souza, E.S., E-mail: msouza@ien.gov.br [Universidade Federal do Rio de Janeiro, COPPE, Centro de Tecnologia, Cidade Universitaria, Bloco G, Ilha do Fundao, 21945-970 Rio de Janeiro, RJ (Brazil); Almeida, G.L., E-mail: gevlisb@hotmail.com [Instituto de Engenharia Nuclear, Reator Argonauta - CNEN Rua Helio de Almeida 75, Cidade Universitária, Ilha do Fundao, Caixa Postal 68550, CEP 21941-972 Rio de Janeiro, RJ (Brazil); Lopes, R.T., E-mail: ricardo@lin.ufrj.br [Universidade Federal do Rio de Janeiro, COPPE, Centro de Tecnologia, Cidade Universitaria, Bloco G, Ilha do Fundao, 21945-970 Rio de Janeiro, RJ (Brazil)

    2016-12-01

    This work posits a novel approach to characterize the divergence of a neutron beam emerging from a reactor port. Unlike the usual inverse of the L/D ratio, the term divergence as employed here refers to the deviation from an ideal parallel beam emitted from a surface source. Within this concept, an ideal point source in spite of its conical beam would not exhibit any divergence. Hence, the beam divergence of a surface source is more adequately characterized adopting the notion of Rocking Curve - RC, a term borrowed from the X-ray diffraction field. After this idea, every point of the surface source emits neutrons in all directions but with different intensities following a bell-shaped profile. Once the RC semi-width is determined, it is possible to assess its effect upon the quality of an acquired neutron radiograph, since it incorporates degrading agents such as geometrical unsharpness, neutron scattering, noise and statistical dispersion. In this work an inverse procedure is applied, i.e., to use an actual neutron radiograph to find the RC semi-width. To accomplish this task, synthetic images - generated with defined RC semi-widths and object-detector gaps - are compared with experimental ones acquired with the same gaps in order to find the most resemblance between them. The angular semi-width of the best synthetic image is assigned to that of the experimental one, defining thus the aimed beam divergence, which has been compared with a different method with a fair agreement. An equivalent procedure embedded in the algorithm has been employed to evaluate the L/D using the same radiographic images. The outcome fairly agrees with the value inferred from the neutron flux ratio at different locations. Both approaches RC semi-width and L/D ratio yielded consistent results with other utterly different methods. Yet, the rocking curve approach forecasts more precisely the neutron pattern hitting the detector and does not need a precisely machined test-object as required

  12. A novel methodology to determine the divergence of a neutron beam

    International Nuclear Information System (INIS)

    Souza, E.S.; Almeida, G.L.; Lopes, R.T.

    2016-01-01

    This work posits a novel approach to characterize the divergence of a neutron beam emerging from a reactor port. Unlike the usual inverse of the L/D ratio, the term divergence as employed here refers to the deviation from an ideal parallel beam emitted from a surface source. Within this concept, an ideal point source in spite of its conical beam would not exhibit any divergence. Hence, the beam divergence of a surface source is more adequately characterized adopting the notion of Rocking Curve - RC, a term borrowed from the X-ray diffraction field. After this idea, every point of the surface source emits neutrons in all directions but with different intensities following a bell-shaped profile. Once the RC semi-width is determined, it is possible to assess its effect upon the quality of an acquired neutron radiograph, since it incorporates degrading agents such as geometrical unsharpness, neutron scattering, noise and statistical dispersion. In this work an inverse procedure is applied, i.e., to use an actual neutron radiograph to find the RC semi-width. To accomplish this task, synthetic images - generated with defined RC semi-widths and object-detector gaps - are compared with experimental ones acquired with the same gaps in order to find the most resemblance between them. The angular semi-width of the best synthetic image is assigned to that of the experimental one, defining thus the aimed beam divergence, which has been compared with a different method with a fair agreement. An equivalent procedure embedded in the algorithm has been employed to evaluate the L/D using the same radiographic images. The outcome fairly agrees with the value inferred from the neutron flux ratio at different locations. Both approaches RC semi-width and L/D ratio yielded consistent results with other utterly different methods. Yet, the rocking curve approach forecasts more precisely the neutron pattern hitting the detector and does not need a precisely machined test-object as required

  13. Design of thermal neutron beam based on an electron linear accelerator for BNCT.

    Science.gov (United States)

    Zolfaghari, Mona; Sedaghatizadeh, Mahmood

    2016-12-01

    An electron linear accelerator (Linac) can be used for boron neutron capture therapy (BNCT) by producing thermal neutron flux. In this study, we used a Varian 2300 C/D Linac and MCNPX.2.6.0 code to simulate an electron-photoneutron source for use in BNCT. In order to decelerate the produced fast neutrons from the photoneutron source, which optimize the thermal neutron flux, a beam-shaping assembly (BSA) was simulated. After simulations, a thermal neutron flux with sharp peak at the beam exit was obtained in the order of 3.09×10 8 n/cm 2 s and 6.19×10 8 n/cm 2 s for uranium and enriched uranium (10%) as electron-photoneutron sources respectively. Also, in-phantom dose analysis indicates that the simulated thermal neutron beam can be used for treatment of shallow skin melanoma in time of about 85.4 and 43.6min for uranium and enriched uranium (10%) respectively. Copyright © 2016. Published by Elsevier Ltd.

  14. Study of computerized tomography using neutron beam

    International Nuclear Information System (INIS)

    Pereira, W.W.

    1991-05-01

    This paper aims to demonstrate the advantages, shortcomings and complementaries of a tomography development using neutrons over the one employing gamma rays in the context of their applications to non destructive essays. A simulated experimental study was performed in order to compare the two aforementioned tomographic procedures as applied to some materials. These materials were chosen for their clear advantages and complementaries as, for instance, aluminium, iron, plastic and aluminium hydroxide. In this work two tomographic systems, are employed both with parallel beams. The first with a gamma radiation source (Caesium-137), with an energy of 662 KeV and an activity of 3,9 x 10 9 Bq (100 mCi) and the second one employing a neutron source, the Argonaut Reactor of the Instituto de Engenharia Nuclear, IEN/CNEN, from where the thermal neutron beam of about 10 5 n/(cm.s) was obtained. It is possible to conclude from the simulated and experimental results, by means of image analysis and distortion measurements, that for a given material the adequate radiation and its energy may be chosen so as to better characterize it. (author)

  15. National facility for neutron beam research

    Indian Academy of Sciences (India)

    In this talk, the growth of neutron beam research (NBR) in India over the past five decades is traced beginning with research at Apsara. A range of problems in condensed matter physics could be studied at CIRUS, followed by sophisticated indegenous instrumentation and research at Dhruva. The talk ends with an overview ...

  16. Development of a sealed-accelerator-tube neutron generator

    Science.gov (United States)

    Verbeke; Leung; Vujic

    2000-10-01

    Sealed-accelerator-tube neutron generators are being developed in Lawrence Berkeley National Laboratory (LBNL) for applications ranging from neutron radiography to boron neutron capture therapy and neutron activation analysis. The new generation of high-output neutron generators is based on the D-T fusion reaction, producing 14.1-MeV neutrons. The main components of the neutron tube--the ion source, the accelerator and the target--are all housed in a sealed metal container without external pumping. Thick-target neutron yield computations are performed in this paper to estimate the neutron yield of titanium and scandium targets. With an average deuteron beam current of 1 A and an energy of 120 keV, a time-averaged neutron production of approximately 10(14) n/s can be estimated for a tritiated target, for both pulsed and cw operations. In mixed deuteron/triton beam operation, a beam current of 2 A at 150 keV is required for the same neutron output. Recent experimental results on ion sources and accelerator columns are presented and discussed.

  17. External beam radiotherapy for unresectable pancreatic cancer

    Energy Technology Data Exchange (ETDEWEB)

    Kagami, Yoshikazu; Nishio, Masamichi; Narimatsu, Naoto; Ogawa, Hajime; Betsuyaku, Takashi; Hirata, Kouji; Ikeda, Shigeyuki (Sapporo National Hospital (Japan). Hokkaido Cancer Center)

    1992-04-01

    Between 1980 to 1989, 24 patients with unresectable pancreatic cancer (10 with localized tumor alone and 14 with distant metastases) have been treated with external beam radiation at Sapporo National Hospital, Hokkaido Cancer Center. Response rate of pancreatic tumor treated with external beam radiation was 33.3% (7/21) with no complete response. Median survival time of the patients with localized tumor was 10 months and that of the patients with distant metastases was 3 months. Relief of pain occurred in 92.9% (12/13) of patients having pain due to pancreatic tumor and in 75% (3/4) of patients having pain due to bone metastases. Major complication was gastric ulcer which developed in 5 patients of 21 patients given stomach irradiation. We concluded that unresectable pancreatic cancer would be frequently indicated for radiotherapy. (author).

  18. Neutron scattering at FRJ-2. Experimental reports 2004

    International Nuclear Information System (INIS)

    Brueckel, T.; Richter, D.; Zorn, R.

    2004-01-01

    The Research Centre FZ-Juelich is offering its neutron research facilities to a growing national and international user community for the benefit of their research using neutron beams. FZ-Juelich operates a 23 MW DIDO reactor that delivers a total neutron flux of 2.9 x 10 14 n/cm 2 s (undisturbed) for a comprehensive suite of 17 instruments installed at 5 individual thermal beam tubes and, in addition, 5 external cold neutron guides. In the year 2004 the reactor was in operation for 208 days and we are happy to announce that more than 150 individual experiments (constituting 61% of the total) were carried out by a large external user community from 85 institutions all over the world. In close collaboration with internal staff the study of soft matter systems took the largest stake. In addition, subjects of biology, magnetism and engineering were among the other main topics of the experimental programme. We gratefully acknowledge the funding programme ''Juelich Neutrons for Europe'' under the European initiative NMI3 that enables numerous external users from the EU and associated countries to come over, visit Juelich and perform their experiments. This book comprises the scientific reports of the experiments completed in 2004. We wish to thank all external users, local applicants, instrument responsibles, and technical staff for their joint efforts and contributions to the success and progress of the Juelich neutron research facility. (orig.)

  19. SU-F-BRE-11: Neutron Measurements Around the Varian TrueBeam Linac

    Energy Technology Data Exchange (ETDEWEB)

    Maglieri, R; Seuntjens, J; Kildea, J [McGill University, Montreal, QC (Canada); Liang, L; DeBlois, F [Jewish General Hospital, Montreal, QC (Canada); Evans, M [Montreal General Hospital, Montreal, QC (Canada); Licea, A [Canadian Nuclear Safety Comission, Ottawa, Ontario (Canada); Dubeau, J; Witharana, S [Detec, Gatineau, QC (Canada)

    2014-06-15

    Purpose: With the emergence of flattening filter free (FFF) photon beams, several authors have noted many advantages to their use. One such advantage is the decrease in neutron production by photonuclear reactions in the linac head. In the present work we investigate the reduction in neutrons from a Varian TrueBeam linac using the Nested Neutron Spectrometer (NNS, Detec). The neutron spectrum, total fluence and source strength were measured and compared for 10 MV with and without flattening filter and the effect of moderation by the room and maze was studied for the 15 MV beam. Methods: The NNS, similar to traditional Bonner sphere detectors but operated in current mode, was used to measure the neutron fluence and spectrum. The NNS was validated for use in high dose rate environments using Monte Carlo simulations and calibrated at NIST and NRC Canada. Measurements were performed at several positions within the treatment room and maze with the linac jaws closed to maximize neutron production. Results: The measurements showed a total fluence reduction between 35-40% in the room and maze when the flattening filter was removed. The neutron source strength Qn was calculated from in-room fluence measurements and was found to be 0.042 × 10{sup 2} n/Gy, 0.026 × 10{sup 2} n/Gy and 0.59 × 101{sup 2} n/Gy for the 10 MV, the 10 MV FFF and 15 MV beams, respectively. We measured ambient equivalent doses of 11 mSv/hr, 7 mSv/hr and 218 mSv/hr for the 10 MV, 10 MV FFF and 15 MV by the head. Conclusion: Our measurements revealed a decrease in total fluence, neutron source strength and equivalent dose of approximately 35-40% across the treatment room for the FFF compared to FF modes. This demonstrates, as expected, that the flattening filter is a major component of the neutron production for the TrueBeam. The authors greatly acknowledge support form the Canadian Nuclear Commission and the Natural Sciences and Engineering Research Council of Canada through the CREATE program. Co

  20. Establishment of nuclear data system - Feasibility study for neutron-beam= facility at pohang accelerator laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Nam Kung, Won; Koh, In Soo; Cho, Moo Hyun; Kim, Kui Nyun; Kwang, Hung Sik; Park, Sung Joo [Pohang Accelerator Laboratory, Pohang (Korea, Republic of)

    1996-12-01

    Nuclear data which have been produced by a few developed countries in the= past are essential elements to many disciplines, especially to nuclear engineering. As we promote our nuclear industry further to the level of advanced countries, we also have to establish the Nuclear Data System to produce and evaluate nuclear data independently. We have studied the possibility to build a neutron-beam facility utilizing accelerator facilities, technologies and man powers at pohang Accelerator Laboratory. We found specific parameters for the PAL 100-MeV electron linac based on the existing klystron, modulator, accelerating tubes and other facilities in the PAL; the beam energy is 60-100 MeV, the beam current for the short pulse (10 ns) is 2 A and for the long pulse is 500 mA and the pulse repetition rate is 60 Hz. We propose a neutron-beam facility using PAL 100-MeV electron linac where we can use a Ta-target for the neutron generation and three different time-of-flight beam lines (10 m, 20 m, and 100 m). One may find that the proposed neutron-beam facility is comparable with other operating neutron facilities in the world. We conclude that the proposed neutron-beam facility utilizing the existing accelerator facility in the PAL would be an excellent facility for neutron data production in combination with the ` Hanaro` facility in KAERI. 8 refs., 11 tabs., 12 figs. (author)

  1. Impurity radiation from a beam-plasma neutron source

    International Nuclear Information System (INIS)

    Molvik, A.W.

    1995-01-01

    Impurity radiation, in a worst case evaluation for a beam-plasma neutron source (BPNS), does not limit performance. Impurities originate from four sources: (a) sputtering from walls by charge exchange or alpha particle bombardment, (b) sputtering from limiters, (c) plasma desorption of gas from walls and (d) injection with neutral beams. Sources (c) and (d) are negligible; adsorbed gas on the walls of the confinement chamber and the neutral beam sources is removed by the steady state discharge. Source (b) is negligible for impinging ion energies below the sputtering threshold (T i ≤ 0.025 keV on tungsten) and for power densities to the limiter within the capabilities of water cooling (30-40 MW/m 2 ); both conditions can be satisfied in the BPNS. Source (a) radiates 0.025 MW/m 2 to the neutron irradiation samples, compared with 5 to 10 MW/m 2 of neutrons; and radiates a total of 0.08 MW from the plasma column, compared with 60 MW of injected power. The particle bombardment that yields source (a) deposits an average of 2.7 MW/m 2 on the samples, within the capabilities of helium gas cooling (10 MW/m 2 ). An additional worst case for source (d) is evaluated for present day 2 to 5 s pulsed neutral beams with 0.1% impurity density and is benchmarked against 2XIIB. The total radiation would increase a factor of 1.5 to ≤ 0.12 MW, supporting the conclusion that impurities will not have a significant impact on a BPN. (author). 61 refs, 7 figs, 2 tabs

  2. Novel design concepts for generating intense accelerator based beams of mono-energetic fast neutrons

    International Nuclear Information System (INIS)

    Franklyn, C.B.; Govender, K.; Guzek, J.; Beer, A. de; Tapper, U.A.S.

    2001-01-01

    Full text: Successful application of neutron techniques in research, medicine and industry depends on the availability of suitable neutron sources. This is particularly important for techniques that require mono-energetic fast neutrons with well defined energy spread. There are a limited number of nuclear reactions available for neutron production and often the reaction yield is low, particularly for thin targets required for the production of mono-energetic neutron beams. Moreover, desired target materials are often in a gaseous form, such as the reactions D(d,n) 3 He and T(d,n) 3 He, requiring innovative design of targets, with sufficient target pressure and particle beam handling capability. Additional requirements, particularly important in industrial applications, and for research institutions with limited funds, are the cost effectiveness as well as small size, coupled with reliable and continuous operation of the system. Neutron sources based on high-power, compact radio-frequency quadrupole (RFQ) linacs can satisfy these criteria, if used with a suitable target system. This paper discusses the characteristics of a deuteron RFQ linear accelerator system coupled to a high pressure differentially pumped deuterium target. Such a source, provides in excess of 10 10 mono- energetic neutrons per second with minimal slow neutron and gamma-ray contamination, and is utilised for a variety of applications in the field of mineral identification and materials diagnostics. There is also the possibility of utilising a proposed enhanced system for isotope production. The RFQ linear accelerator consists of: 1) Deuterium 25 keV ion source injector; 2) Two close-coupled RFQ resonators, each powered by an rf amplifier supplying up to 300 kW of peak power at 425 MHz; 3) High energy beam transport system consisting of a beam line, a toroid for beam current monitoring, two steering magnets and a quadrupole triplet for beam focusing. Basic technical specifications of the RFQ linac

  3. From x-ray telescopes to neutron scattering: Using axisymmetric mirrors to focus a neutron beam

    International Nuclear Information System (INIS)

    Khaykovich, B.; Gubarev, M.V.; Bagdasarova, Y.; Ramsey, B.D.; Moncton, D.E.

    2011-01-01

    We demonstrate neutron beam focusing by axisymmetric mirror systems based on a pair of mirrors consisting of a confocal ellipsoid and hyperboloid. Such a system, known as a Wolter mirror configuration, is commonly used in X-ray telescopes. The axisymmetric Wolter geometry allows nesting of several mirror pairs to increase collection efficiency. We implemented a system containing four nested Ni mirror pairs, which was tested by the focusing of a polychromatic neutron beam at the MIT Reactor. In addition, we have carried out extensive ray-tracing simulations of the mirrors and their performance in different situations. The major advantages of the Wolter mirrors are nesting for large angular collection and aberration-free performance. We discuss how these advantages can be utilized to benefit various neutron scattering methods, such as imaging, SANS, and time-of-flight spectroscopy.

  4. Low-energy beam transport studies supporting the spallation neutron source 1-MW beam operation.

    Science.gov (United States)

    Han, B X; Kalvas, T; Tarvainen, O; Welton, R F; Murray, S N; Pennisi, T R; Santana, M; Stockli, M P

    2012-02-01

    The H(-) injector consisting of a cesium enhanced RF-driven ion source and a 2-lens electrostatic low-energy beam transport (LEBT) system supports the spallation neutron source 1 MW beam operation with ∼38 mA beam current in the linac at 60 Hz with a pulse length of up to ∼1.0 ms. In this work, two important issues associated with the low-energy beam transport are discussed: (1) inconsistent dependence of the post-radio frequency quadrupole accelerator beam current on the ion source tilt angle and (2) high power beam losses on the LEBT electrodes under some off-nominal conditions compromising their reliability.

  5. Pulsed White Spectrum Neutron Generator for Explosive Detection

    International Nuclear Information System (INIS)

    King, Michael J.; Miller, Gill T.; Reijonen, Jani; Ji, Qing; Andresen, Nord; Gicquel, Frederic; Kavlas, Taneli; Leung, Ka-Ngo; Kwan, Joe

    2008-01-01

    Successful explosive material detection in luggage and similar sized containers is a critical issue in securing the safety of all airline passengers. Tensor Technology Inc. has recently developed a methodology that will detect explosive compounds with pulsed fast neutron transmission spectroscopy. In this scheme, tritium beams will be used to generate neutrons with a broad energy spectrum as governed by the T(t,2n)4He fission reaction that produces 0-9 MeV neutrons. Lawrence Berkeley National Laboratory (LBNL), in collaboration with Tensor Technology Inc., has designed and fabricated a pulsed white-spectrum neutron source for this application. The specifications of the neutron source are demanding and stringent due to the requirements of high yield and fast pulsing neutron emission, and sealed tube, tritium operation. In a unique co-axial geometry, the ion source uses ten parallel rf induction antennas to externally couple power into a toroidal discharge chamber. There are 20 ion beam extraction slits and 3 concentric electrode rings to shape and accelerate the ion beam into a titanium cone target. Fast neutron pulses are created by using a set of parallel-plate deflectors switching between +-1500 volts and deflecting the ion beams across a narrow slit. The generator is expected to achieve 5 ns neutron pulses at tritium ion beam energies between 80-120 kV. First experiments demonstrated ion source operation and successful beam pulsing

  6. Detailed characterisation of the incident neutron beam on the TOSCA spectrometer

    Science.gov (United States)

    Pinna, Roberto S.; Rudić, Svemir; Capstick, Matthew J.; McPhail, David J.; Pooley, Daniel E.; Howells, Gareth D.; Gorini, Giuseppe; Fernandez-Alonso, Felix

    2017-10-01

    We report a detailed characterisation of the incident neutron beam on the TOSCA spectrometer. A bespoke time-of-flight neutron monitor has been designed, constructed and used to perform extensive spatially resolved measurements of the absolute neutron flux and its underlying time structure at the instrument sample position. The obtained data give a quantitative understanding of the current instrument beyond neutronic simulations and provide a baseline in order to assess the performance of the upgraded instrument. At an average proton current-on-target of 153 μA (ISIS Target Station 1; at the time of measurements) we have found that the wavelength-integrated neutron flux (from 0.28 Å to 4.65 Å) at the position of the TOSCA instrument sample (spatially averaged across the 3 × 3cm2 surface centred around (0,0) position) is approximately 1 . 2 × 106 neutrons cm-2s-1, while the whole beam has a homogeneous distribution across the 3 . 0 × 3 . 5cm2 sample surface. The spectra reproduced the well-known shape of the neutrons moderated by the room temperature water moderator and exhibit a neutron flux of 7 . 3 × 105 neutrons cm-2s-1Å-1 at 1 Å.

  7. Prestress Force Identification for Externally Prestressed Concrete Beam Based on Frequency Equation and Measured Frequencies

    Directory of Open Access Journals (Sweden)

    Luning Shi

    2014-01-01

    Full Text Available A prestress force identification method for externally prestressed concrete uniform beam based on the frequency equation and the measured frequencies is developed. For the purpose of the prestress force identification accuracy, we first look for the appropriate method to solve the free vibration equation of externally prestressed concrete beam and then combine the measured frequencies with frequency equation to identify the prestress force. To obtain the exact solution of the free vibration equation of multispan externally prestressed concrete beam, an analytical model of externally prestressed concrete beam is set up based on the Bernoulli-Euler beam theory and the function relation between prestress variation and vibration displacement is built. The multispan externally prestressed concrete beam is taken as the multiple single-span beams which must meet the bending moment and rotation angle boundary conditions, the free vibration equation is solved using sublevel simultaneous method and the semi-analytical solution of the free vibration equation which considered the influence of prestress on section rigidity and beam length is obtained. Taking simply supported concrete beam and two-span concrete beam with external tendons as examples, frequency function curves are obtained with the measured frequencies into it and the prestress force can be identified using the abscissa of the crosspoint of frequency functions. Identification value of the prestress force is in good agreement with the test results. The method can accurately identify prestress force of externally prestressed concrete beam and trace the trend of effective prestress force.

  8. Summary of mirror experiments relevant to beam-plasma neutron source

    International Nuclear Information System (INIS)

    Molvik, A.W.

    1988-01-01

    A promising design for a deuterium-tritium (DT) neutron source is based on the injection of neutral beams into a dense, warm plasma column. Its purpose is to test materials for possible use in fusion reactors. A series of designs have evolved, from a 4-T version to an 8-T version. Intense fluxes of 5--10 MW/m 2 is achieved at the plasma surface, sufficient to complete end-of-life tests in one to two years. In this report, we review data from earlier mirror experiments that are relevant to such neutron sources. Most of these data are from 2XIIB, which was the only facility to ever inject 5 MW of neutral beams into a single mirror call. The major physics issues for a beam-plasma neutron source are magnetohydrodynamic (MHD) equilibrium and stability, microstability, startup, cold-ion fueling of the midplane to allow two-component reactions, and operation in the Spitzer conduction regime, where the power is removed to the ends by an axial gradient in the electron temperature T/sub e/. We show in this report that the conditions required for a neutron source have now been demonstrated in experiments. 20 refs., 15 figs., 3 tabs

  9. Metrology and quality of radiation therapy dosimetry of electron, photon and epithermal neutron beams

    Energy Technology Data Exchange (ETDEWEB)

    Kosunen, A

    1999-08-01

    In radiation therapy using electron and photon beams the dosimetry chain consists of several sequential phases starting by the realisation of the dose quantity in the Primary Standard Dosimetry Laboratory and ending to the calculation of the dose to a patient. A similar procedure can be described for the dosimetry of epithermal neutron beams in boron neutron capture therapy (BNCT). To achieve the required accuracy of the dose delivered to a patient the quality of all steps in the dosimetry procedure has to be considered. This work is focused on two items in the dosimetry chains: the determination of the dose in the reference conditions and the evaluation of the accuracy of dose calculation methods. The issues investigated and discussed in detail are: a)the calibration methods of plane parallel ionisation chambers used in electron beam dosimetry, (b) the specification of the critical dosimetric parameter i.e. the ratio of stopping powers for water to air, (S I ?){sup water} {sub air}, in photon beams, (c) the feasibility of the twin ionization chamber technique for dosimetry in epithermal neutron beams applied to BNCT and (d) the determination accuracy of the calculated dose distributions in phantoms in electron, photon, and epithermal neutron beams. The results demonstrate that up to a 3% improvement in the consistency of dose determinations in electron beams is achieved by the calibration of plane parallel ionisation chambers in high energy electron beams instead of calibrations in {sup 60}Co gamma beams. In photon beam dosimetry (S I ?){sup water} {sub air} can be determined with an accuracy of 0.2% using the percentage dose at the 10 cm depth, %dd(10), as a beam specifier. The use of %odd(10) requires the elimination of the electron contamination in the photon beam. By a twin ionisation chamber technique the gamma dose can be determined with uncertainty of 6% (1 standard deviation) and the total neutron dose with an uncertainty of 15 to 20% (1 standard deviation

  10. Metrology and quality of radiation therapy dosimetry of electron, photon and epithermal neutron beams

    International Nuclear Information System (INIS)

    Kosunen, A.

    1999-08-01

    In radiation therapy using electron and photon beams the dosimetry chain consists of several sequential phases starting by the realisation of the dose quantity in the Primary Standard Dosimetry Laboratory and ending to the calculation of the dose to a patient. A similar procedure can be described for the dosimetry of epithermal neutron beams in boron neutron capture therapy (BNCT). To achieve the required accuracy of the dose delivered to a patient the quality of all steps in the dosimetry procedure has to be considered. This work is focused on two items in the dosimetry chains: the determination of the dose in the reference conditions and the evaluation of the accuracy of dose calculation methods. The issues investigated and discussed in detail are: a)the calibration methods of plane parallel ionisation chambers used in electron beam dosimetry, (b) the specification of the critical dosimetric parameter i.e. the ratio of stopping powers for water to air, (S I ?) water air , in photon beams, (c) the feasibility of the twin ionization chamber technique for dosimetry in epithermal neutron beams applied to BNCT and (d) the determination accuracy of the calculated dose distributions in phantoms in electron, photon, and epithermal neutron beams. The results demonstrate that up to a 3% improvement in the consistency of dose determinations in electron beams is achieved by the calibration of plane parallel ionisation chambers in high energy electron beams instead of calibrations in 60 Co gamma beams. In photon beam dosimetry (S I ?) water air can be determined with an accuracy of 0.2% using the percentage dose at the 10 cm depth, %dd(10), as a beam specifier. The use of %odd(10) requires the elimination of the electron contamination in the photon beam. By a twin ionisation chamber technique the gamma dose can be determined with uncertainty of 6% (1 standard deviation) and the total neutron dose with an uncertainty of 15 to 20% (1 standard deviation). To improve the accuracy

  11. Neutron Spectroscopy for pulsed beams with frame overlap using a double time-of-flight technique

    Science.gov (United States)

    Harrig, K. P.; Goldblum, B. L.; Brown, J. A.; Bleuel, D. L.; Bernstein, L. A.; Bevins, J.; Harasty, M.; Laplace, T. A.; Matthews, E. F.

    2018-01-01

    A new double time-of-flight (dTOF) neutron spectroscopy technique has been developed for pulsed broad spectrum sources with a duty cycle that results in frame overlap, where fast neutrons from a given pulse overtake slower neutrons from previous pulses. Using a tunable beam at the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory, neutrons were produced via thick-target breakup of 16 MeV deuterons on a beryllium target in the cyclotron vault. The breakup spectral shape was deduced from a dTOF measurement using an array of EJ-309 organic liquid scintillators. Simulation of the neutron detection efficiency of the scintillator array was performed using both GEANT4 and MCNP6. The efficiency-corrected spectral shape was normalized using a foil activation technique to obtain the energy-dependent flux of the neutron beam at zero degrees with respect to the incoming deuteron beam. The dTOF neutron spectrum was compared to spectra obtained using HEPROW and GRAVEL pulse height spectrum unfolding techniques. While the unfolding and dTOF results exhibit some discrepancies in shape, the integrated flux values agree within two standard deviations. This method obviates neutron time-of-flight spectroscopy challenges posed by pulsed beams with frame overlap and opens new opportunities for pulsed white neutron source facilities.

  12. System for detecting neutrons in the harsh radiation environment of a relativistic electron beam

    International Nuclear Information System (INIS)

    Kruse, L.W.

    1978-06-01

    Newly developed detectors and procedures allow measurement of neutron yield and energy in the harsh radiation environment of a relativistic electron beam source. A new photomultiplier tube design and special gating methods provide the basis for novel time-of-flight and total-yield detectors. The technique of activation analysis is expanded to provide a neutron energy spectrometer. There is a demonstrated potential in the use of the integrated system as a valuable diagnostic tool to study particle-beam fusion, intense ion-beam interactions, and pulsed neutron sources for simulating weapons effects. A physical lower limit of 10 8 neutrons into 4π is established for accurate and meaningful measurements in the REB environment

  13. Instrumentation to handle thermal polarized neutron beams

    NARCIS (Netherlands)

    Kraan, W.H.

    2004-01-01

    In this thesis we investigate devices needed to handle the polarization of thermal neutron beams: Ï/2-flippers (to start/stop Larmor precession) and Ï-flippers (to reverse polarization/precession direction) and illustrate how these devices are used to investigate the properties of matter and of the

  14. Proton external beam in the TANDAR Accelerator

    International Nuclear Information System (INIS)

    Rey, R.; Schuff, J.A.; Perez de la Hoz, A.; Debray, M.E.; Hojman, D.; Kreiner, A.J.; Kesque, J.M.; Saint-Martin, G.; Oppezzo, O.; Bernaola, O.A.; Molinari, B.L.; Duran, H.A.; Policastro, L.; Palmieri, M.; Ibanez, J.; Stoliar, P.; Mazal, A.; Caraballo, M.E.; Burlon, A.; Cardona, M.A.; Vazquez, M.E.; Salfity, M.F.; Ozafran, M.J.; Naab, F.; Levinton, G.; Davidson, M.; Buhler, M.

    1998-01-01

    An external proton beam has been obtained in the TANDAR accelerator with radiological and biomedical purposes. The protons have excellent physical properties for their use in radiotherapy allowing a very good accuracy in the dose spatial distribution inside the tissue so in the side direction as in depth owing to the presence of Bragg curve. The advantage of the accuracy in the dose localization with proton therapy is good documented (M. Wagner, Med. Phys. 9, 749 (1982); M. Goitein and F. Chen, Med. Phys. 10, 831 (1983); M.R. Raju, Rad. Res. 145, 391 (1996)). It was obtained external proton beams with energies between 15-25 MeV, currents between 2-10 p A and a uniform transversal sections of 40 mm 2 approximately. It was realized dosimetric evaluations with CR39 and Makrofol foliation. The irradiations over biological material contained experiences In vivo with laboratory animals, cellular and bacterial crops. It was fixed the optimal conditions of position and immobilization of the Wistar rats breeding for the In vivo studies. It was chosen dilutions and sowing techniques adequate for the exposition at the cellular and bacterial crops beam. (Author)

  15. Overview on neutron beam industry-focused strategic research in Malaysia

    International Nuclear Information System (INIS)

    Abdul Aziz Mohamed; Razali Kassim; Abdul Jalil Abdul Hamid; Azali Muhammad; Muhammad Rawi Mohd Zain; Azhar Azmi

    2002-01-01

    The TRIGA MARK II research reactor (RTP) at the Malaysian Institute for Nuclear Technology Research (MINT) was commissioned in July 1982. RTP is a 1 MW steady state reactor which being used for reactor training and research related to neutron. Since then various works have been performed to utilise the neutrons produced from this steady state reactor. Projects undertaken are the development and utilization of the neutron radiography (myNR) and small angle neutron scattering (mySANS) facilities. This poster highlights the recent status the above neutron beam facilities and their application in materials science and technology research and education. (Author)

  16. Overview of the Conceptual Design of the Future VENUS Neutron Imaging Beam Line at the Spallation Neutron Source

    Science.gov (United States)

    Bilheux, Hassina; Herwig, Ken; Keener, Scott; Davis, Larry

    VENUS (Versatile Neutron Imaging Beam line at the Spallation Neutron Source) will be a world-class neutron-imaging instrument that will uniquely utilize the Spallation Neutron Source (SNS) time-of-flight (TOF) capabilities to measure and characterize objects across several length scales (mm to μm). When completed, VENUS will provide academia, industry and government laboratories with the opportunity to advance scientific research in areas such as energy, materials, additive manufacturing, geosciences, transportation, engineering, plant physiology, biology, etc. It is anticipated that a good portion of the VENUS user community will have a strong engineering/industrial research focus. Installed at Beam line 10 (BL10), VENUS will be a 25-m neutron imaging facility with the capability to fully illuminate (i.e., umbra illumination) a 20 cm x 20 cm detector area. The design allows for a 28 cm x 28 cm field of view when using the penumbra to 80% of the full illumination flux. A sample position at 20 m will be implemented for magnification measurements. The optical components are comprised of a series of selected apertures, T0 and bandwidth choppers, beam scrapers, a fast shutter to limit sample activation, and flight tubes filled with Helium. Techniques such as energy selective, Bragg edge and epithermal imaging will be available at VENUS.

  17. Reactions with fast radioactive beams of neutron-rich nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Aumann, T. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany)

    2005-11-01

    The neutron dripline has presently been reached only for the lightest nuclei up to the element oxygen. In this region of light neutron-rich nuclei, scattering experiments are feasible even for dripline nuclei by utilizing high-energy secondary beams produced by fragmentation. In the present article, reactions of high-energy radioactive beams will be exemplified using recent experimental results mainly derived from measurements of breakup reactions performed at the LAND and FRS facilities at GSI and at the S800 spectrometer at the NSCL. Nuclear and electromagnetically induced reactions allow probing different aspects of nuclear structure at the limits of stability related to the neutron-proton asymmetry and the weak binding close to the dripline. Properties of the valence-neutron wave functions are studied in the one-neutron knockout reaction, revealing the changes of shell structure when going from the beta-stability line to more asymmetric loosely bound neutron-rich systems. The vanishing of the N=8 shell gap for neutron-rich systems like {sup 11}Li and {sup 12}Be, or the new closed N=14, 16 shells for the oxygen isotopes are examples. The continuum of weakly bound nuclei and halo states can be studied by inelastic scattering. The dipole response, for instance, is found to change dramatically when going away from the valley of stability. A redistribution of the dipole strength towards lower excitation energies is observed for neutron-rich nuclei, which partly might be due to a new collective excitation mode related to the neutron-proton asymmetry. Halo nuclei in particular show strong dipole transitions to the continuum at the threshold, being directly related to the ground-state properties of the projectile. Finally, an outlook on future experimental prospects is given. (orig.)

  18. Reactions with fast radioactive beams of neutron-rich nuclei

    International Nuclear Information System (INIS)

    Aumann, T.

    2005-11-01

    The neutron dripline has presently been reached only for the lightest nuclei up to the element oxygen. In this region of light neutron-rich nuclei, scattering experiments are feasible even for dripline nuclei by utilizing high-energy secondary beams produced by fragmentation. In the present article, reactions of high-energy radioactive beams will be exemplified using recent experimental results mainly derived from measurements of breakup reactions performed at the LAND and FRS facilities at GSI and at the S800 spectrometer at the NSCL. Nuclear and electromagnetically induced reactions allow probing different aspects of nuclear structure at the limits of stability related to the neutron-proton asymmetry and the weak binding close to the dripline. Properties of the valence-neutron wave functions are studied in the one-neutron knockout reaction, revealing the changes of shell structure when going from the beta-stability line to more asymmetric loosely bound neutron-rich systems. The vanishing of the N=8 shell gap for neutron-rich systems like 11 Li and 12 Be, or the new closed N=14, 16 shells for the oxygen isotopes are examples. The continuum of weakly bound nuclei and halo states can be studied by inelastic scattering. The dipole response, for instance, is found to change dramatically when going away from the valley of stability. A redistribution of the dipole strength towards lower excitation energies is observed for neutron-rich nuclei, which partly might be due to a new collective excitation mode related to the neutron-proton asymmetry. Halo nuclei in particular show strong dipole transitions to the continuum at the threshold, being directly related to the ground-state properties of the projectile. Finally, an outlook on future experimental prospects is given. (orig.)

  19. Investigation on the neutron beam characteristics for boron neutron capture therapy with 3D and 2D transport calculations

    International Nuclear Information System (INIS)

    Kodeli, I.; Diop, C.M.; Nimal, J.C.

    1994-01-01

    In the framework of future Boron Neutron Capture Therapy (BNCT) experiments, where cells and animals irradiations are planned at the research reactor of Strasbourg University, the feasibility to obtain a suitable epithermal neutron beam is investigated. The neutron fluence and spectra calculations in the reactor are performed using the 3D Monte Carlo code TRIPOLI-3 and the 2D SN code TWODANT. The preliminary analysis of Al 2 O 3 and Al-Al 2 O 3 filters configurations are carried out in an attempt to optimize the flux characteristics in the beam tube facility. 7 figs., 7 refs

  20. Beam neutron energy optimization for boron neutron capture therapy using monte Carlo method

    International Nuclear Information System (INIS)

    Pazirandeh, A.; Shekarian, E.

    2006-01-01

    In last two decades the optimal neutron energy for the treatment of deep seated tumors in boron neutron capture therapy in view of neutron physics and chemical compounds of boron carrier has been under thorough study. Although neutron absorption cross section of boron is high (3836b), the treatment of deep seated tumors such as glioblastoma multiform requires beam of neutrons of higher energy that can penetrate deeply into the brain and thermalized in the proximity of the tumor. Dosage from recoil proton associated with fast neutrons however poses some constraints on maximum neutron energy that can be used in the treatment. For this reason neutrons in the epithermal energy range of 10eV-10keV are generally to be the most appropriate. The simulation carried out by Monte Carlo methods using MCBNCT and MCNP4C codes along with the cross section library in 290 groups extracted from ENDF/B6 main library. The ptimal neutron energy for deep seated tumors depends on the sue and depth of tumor. Our estimated optimized energy for the tumor of 5cm wide and 1-2cm thick stands at 5cm depth is in the range of 3-5keV

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-09-21

    The design of a low-power prototype of neutron amplifier recently proposed within the INFN-E project indicated the need for more accurate data on the neutron yield produced by a proton beam with energy of about 70 MeV impinging on a thick beryllium target. Such measurement was performed at the LNS superconducting cyclotron, covering a wide angular range from 0° to 150° and a complete neutron energy interval from thermal to beam energy. Neutrons with energy above 0.5 MeV were measured by liquid scintillators exploiting their time of flight to determine the kinetic energy. For lower energy neutrons, down to thermal energy, a {sup 3}He detector was used. The obtained data are in good agreement with previous measurements at 0° using 66 MeV proton beam, covering neutron energies >10MeV, as well as with measurements at few selected angles using protons of 46, 55 and 113 MeV energy. The present results extend the neutron yield data in the 60–70 MeV beam energy range. A comparison of measured yields to MCNP, FLUKA and Geant4 Monte Carlo simulations was performed.

  2. Development and Commissioning of an External Beam Facility in the Union College Ion Beam Analysis Laboratory

    Science.gov (United States)

    Yoskowitz, Joshua; Clark, Morgan; Labrake, Scott; Vineyard, Michael

    2015-10-01

    We have developed an external beam facility for the 1.1-MV tandem Pelletron accelerator in the Union College Ion Beam Analysis Laboratory. The beam is extracted from an aluminum pipe through a 1 / 4 ' ' diameter window with a 7.5- μm thick Kapton foil. This external beam facility allows us to perform ion beam analysis on samples that cannot be put under vacuum, including wet samples and samples too large to fit into the scattering chamber. We have commissioned the new facility by performing proton induced X-ray emission (PIXE) analysis of several samples of environmental interest. These include samples of artificial turf, running tracks, and a human tooth with an amalgam filling. A 1.7-MeV external proton beam was incident on the samples positioned 2 cm from the window. The resulting X-rays were measured using a silicon drift detector and were analyzed using GUPIX software to determine the concentrations of elements in the samples. The results on the human tooth indicate that while significant concentrations of Hg, Ag, and Sn are present in the amalgam filling, only trace amounts of Hg appear to have leached into the tooth. The artificial turf and running tracks show rather large concentrations of a broad range of elements and trace amounts of Pb in the turf infill.

  3. Characterization of a polychromatic neutron beam diffracted by pyrolytic graphite crystals

    CERN Document Server

    Byun, S H; Choi, H D

    2002-01-01

    The beam spectrum for polychromatic neutrons diffracted by pyrolytic graphite crystals was characterized. The theoretical beam spectrum was obtained using the diffraction model for a mosaic crystal. The lattice vibration effects were included in the calculation using the reported vibration amplitude of the crystal and the measured time-of-flight spectra in the thermal region. The calculated beam spectrum was compared with the results obtained in the absence of thermal motion. The lattice vibration effects became more important for the higher diffraction orders and a large decrease in the neutron flux induced by the vibrations was identified in the epithermal region. The validity of the beam spectrum was estimated by comparing with the effective quantities determined from prompt gamma-ray measurements and Cd-ratios measured both for 1/nu and non-1/nu nuclides.

  4. Design of an irradiation facility with thermal, epithermal and fast neutron beams

    International Nuclear Information System (INIS)

    Pfister, G.; Bernnat, W.; Seidel, R.; Schatz, A.K.; Wagner, F.M.; Waschkowski, W.; Schraube, H.

    1992-01-01

    The main features of a neutron irradiation facility to be installed at the planned research reactor FRM-II are presented. In addition to the operational possibilities of the existing facility at the reactor FRM-I, the new facility will produce quasi-monoenergetic neutron fields and a neutron beam in the keV region whose spectrum can be modified by application of suitable filters and scatterers. For this beam, which is well suited for boron capture therapy, calculated boron reaction rates inside a phantom and an experimental verification of the calculations at the existing facility are presented. (orig.) [de

  5. Measurement of Relative Biological Effectiveness (RBE) for the Radiation Beam from Neutron Source Reactor YAYOI -Comparisons with Cyclotron Neutron and 60Co Gamma Ray-

    OpenAIRE

    HIROAKI, WAKABAYASHI; SHOZO, SUZUKI; AKIRA, ITO; Nuclear Engineering Research Laboratory, Faculty of Engineering, the University of Tokyo; Institute of Medical Science, the University of Tokyo; Institute of Medical Science, the University of Tokyo

    1983-01-01

    Radiation biology and/or therapy research and development for a research reactor beam need specific RBEs of neutrons as well as of specific reactions. RBEs for reactor beams measured in situ condition are interesting because actual radiation effects on each biological system are different depending on detailed conditions of irradiation. A small powered research reactor (Fast Neutron Source Reactor: YAYOI) was examined here as a neutron beam source for obtaining survival curves in a manner usu...

  6. Study of the production of neutron-rich isotope beams issuing from fissions induced by fast neutrons

    International Nuclear Information System (INIS)

    Lau, Ch.

    2000-01-01

    This work is a contribution to the PARRNe project (production of radioactive neutron-rich isotopes). This project is based on the fission fragments coming from the fission of 238-uranium induced by fast neutrons. The fast neutron flux is produced by the collisions of deutons in a converter. Thick targets of uranium carbide and liquid uranium targets have been designed in order to allow a quick release of fission fragments. A device, able to trap on a cryogenic thimble rare gas released by the target, has allowed the production of radioactive nuclei whose half-life is about 1 second. This installation has been settled to different deuton accelerators in the framework of the European collaboration SPIRAL-2. A calibration experiment has proved the feasibility of fixing an ISOL-type isotope separator to a 15 MV tandem accelerator, this installation can provide 500 nA deutons beams whose energy is 26 MeV and be a valuable tool for studying fast-neutron induced fission. Zinc, krypton, rubidium, cadmium, iodine, xenon and cesium beams have been produced in this installation. The most intense beams reach 10000 nuclei by micro-coulomb for 26 MeV deutons. An extra gain of 2 magnitude orders can be obtained by using a more specific ion source and by increasing the thickness of the target. Another extra gain of 2 magnitude orders involves 100 MeV deutons

  7. Establishment of the Neutron Beam Research Facility at the OPAL Reactor

    International Nuclear Information System (INIS)

    Kennedy, S.J.; Robinson, R.A.

    2012-01-01

    Full text: Australia's first research reactor, HIFAR, reached criticality in January 1958. At that time Australia's main agenda was establishment of a nuclear power program. HIFAR operated for nearly 50 years, providing a firm foundation for the establishment of Australia's second generation research Reactor OPAL, which reached criticality in August 006. In HIFAR's early years a neutron beam facility was established for materials characterization, partly in aid of the nuclear energy agenda and partly in response to interest from Australia's scientific community. By the time Australia's nuclear energy program ceased (in the 1970s), radioisotope production and research had also been established at Lucas Heights. Also, by this time the neutron beam facility for scientific research had evolved into a major utilization programme, warranting establishment of an independent body to facilitate scientific access (the Australian Institute for Nuclear Science and Engineering). In HIFAR's lifetime, ANSTO established a radiopharmaceuticals service for the Australian medical community and NDT silicon production was also established and grew to maturity. So when time came to determine the strategy for nuclear research in Australia into the 21st century, it was clear that the replacement for HIFAR should be multipurpose, with major emphases on scientific applications of neutron beams and medical isotope production. With this strategy in mind, ANSTO set about to design and build OPAL with a world-class neutron beam facility, capable of supporting a large and diverse scientific research community. The establishment of the neutron beam facility became the mission of the Bragg Institute management team. This journey began in 1997 with establishment of a working budget, and reached its first major objective when OPAL reached 20 MW thermal power nearly one decade later (in 2006). The first neutron beam instruments began operation soon after (in 2007), and quickly proved themselves to be

  8. Physical parameters and biological effects of the LVR-15 epithermal neutron beam

    International Nuclear Information System (INIS)

    Burian, J.; Marek, M.; Rejchrt, J.; Viererbl, L.; Gambarini, G.; Mares, V.; Vanossi, E.; Judas, L.

    2006-01-01

    Monitoring of the physical and biological properties of the epithermal neutron beam constructed at the multipurpose LVR-15 nuclear reactor for NCT therapy of brain tumors showed that its physical and biological properties are stable in time and independent on an ad hoc reconfiguration of the reactor core before its therapeutic use. Physical parameters were monitored by measurement of the neutron spectrum, neutron profile, fast neutron kerma rate in tissue and photon absorbed dose, the gel dosimetry was used with the group of standard measurement methods. The RBE of the beam, as evaluated by 3 different biological models, including mouse intestine crypt regeneration assay, germinative zones of the immature rat brain and C6 glioma cells in culture, ranged from 1.70 to 1.99. (author)

  9. Use of Neutron Beams for Materials Research Relevant to the Nuclear Energy Sector

    International Nuclear Information System (INIS)

    2015-10-01

    Nuclear technologies such as fission and fusion reactors, including associated waste storage and disposal, rely on the availability of not only nuclear fuels but also advanced structural materials. In 2010–2013, the IAEA organized and implemented the Coordinated Research Project (CRP) on Development, Characterization and Testing of Materials of Relevance to Nuclear Energy Sector Using Neutron Beams. A total of 19 institutions from 18 Member States (Argentina, Australia, Brazil, China, Czech Republic, France, Germany, Hungary, Indonesia, Italy, Japan, Netherlands, Republic of Korea, Romania, Russian Federation (two institutions), South Africa, Switzerland and United States of America) cooperated with the main objective to address the use of various neutron beam techniques for characterization, testing and qualification of materials and components produced or under development for applications in the nuclear energy sector. This CRP aimed to bring stakeholders and end users of research reactors and accelerator based neutron sources together for the enhanced use of available facilities and development of new infrastructures for applied materials research. Work envisioned under this CRP was related to the optimization and validation of neutron beam techniques, including facility and instrument modifications/optimizations as well as improved data acquisition, processing and analysis systems. Particular emphasis was placed on variable environments during material characterization and testing as required by some applications such as intensive irradiation load, high temperature and high pressure conditions, and the presence of strong magnetic fields. Targeted neutron beam techniques were neutron diffraction, small angle neutron scattering and digital neutron radiography/tomography. This publication is a compilation of the main results and findings of the CRP, and the CD-ROM accompanying this publication contains 19 reports with additional relevant technical details

  10. 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.

  11. Comparison of neutron and high-energy X-ray dual-beam radiography for air cargo inspection

    International Nuclear Information System (INIS)

    Liu, Y.; Sowerby, B.D.; Tickner, J.R.

    2008-01-01

    Dual-beam radiography techniques utilising various combinations of high-energy X-rays and neutrons are attractive for screening bulk cargo for contraband such as narcotics and explosives. Dual-beam radiography is an important enhancement to conventional single-beam X-ray radiography systems in that it provides additional information on the composition of the object being imaged. By comparing the attenuations of transmitted dual high-energy beams, it is possible to build a 2D image, colour coded to indicate material. Only high-energy X-rays, gamma-rays and neutrons have the required penetration to screen cargo containers. This paper reviews recent developments and applications of dual-beam radiography for air cargo inspection. These developments include dual high-energy X-ray techniques as well as fast neutron and gamma-ray (or X-ray) radiography systems. High-energy X-ray systems have the advantage of generally better penetration than neutron systems, depending on the material being interrogated. However, neutron systems have the advantage of much better sensitivity to material composition compared to dual high-energy X-ray techniques. In particular, fast neutron radiography offers the potential to discriminate between various classes of organic material, unlike dual energy X-ray techniques that realistically only offer the ability to discriminate between organic and metal objects

  12. Development of a monoenergetic neutron beam (Theoretical aspects, experimental developments and applications)

    International Nuclear Information System (INIS)

    Varela G, A.

    2003-01-01

    By the use of a neutron time of flight system at the Tandem Accelerator of the National Nuclear Research Institute; with neutrons provided by means of the 2 H(d, n) 3 He we intend to use the associated particle technique in order to have monoenergetic neutrons. This neutron beam will be used both in basic and applied research. (Author)

  13. The structure of neutron-rich nuclei explored via in-beam gamma-ray spectroscopy of fast beams

    International Nuclear Information System (INIS)

    Glasmacher, T.; Campbell, C.M.; Church, J.A.; Dinca, D.C.; Hansen, P.G.; Olliver, H.; Perry, B.C.; Sherrill, B.M.; Terry, J.R.; Bazin, D.; Enders, J.; Gade, A.; Hu, Z.; Mueller, W.F.

    2003-01-01

    In-beam gamma-ray spectroscopy with fast exotic beams provides an efficient tool to study bound states in exotic neutron-rich nuclei. Specialized experimental techniques have been developed and explore different aspects of nuclear structure. Inelastic scattering experiments with γ-ray detection can measure the response of exotic nuclei to electromagnetic (Coulomb excitation with a heavy target) or hadronic probes (proton scattering with hydrogen target). In-beam fragmentation populates higher-lying bound states to establish levels. Single- and two-nucleon knockout reactions allow for detailed wavefunction spectroscopy of individual levels and for the measurement of spectroscopic factors. Experimental programs employing these techniques are now underway at all projectile-fragmentation facilities around the world. Here we report on several successful in-beam gamma-ray spectroscopy experiments that have been performed at the Coupled Cyclotron Facility at Michigan State University with an emphasis on elucidating the evolution of nuclear structure around neutron numbers N=16, N=20, and N=28 in the π(sd) shell. (orig.)

  14. High-efficiency resonant rf spin rotator with broad phase space acceptance for pulsed polarized cold neutron beams

    Directory of Open Access Journals (Sweden)

    P.-N. Seo

    2008-08-01

    Full Text Available High precision fundamental neutron physics experiments have been proposed for the intense pulsed spallation neutron beams at JSNS, LANSCE, and SNS to test the standard model and search for new physics. Certain systematic effects in some of these experiments have to be controlled at the few ppb level. The NPDGamma experiment, a search for the small parity-violating γ-ray asymmetry A_{γ} in polarized cold neutron capture on parahydrogen, is one example. For the NPDGamma experiment we developed a radio-frequency resonant spin rotator to reverse the neutron polarization in a 9.5  cm×9.5  cm pulsed cold neutron beam with high efficiency over a broad cold neutron energy range. The effect of the spin reversal by the rotator on the neutron beam phase space is compared qualitatively to rf neutron spin flippers based on adiabatic fast passage. We discuss the design of the spin rotator and describe two types of transmission-based neutron spin-flip efficiency measurements where the neutron beam was both polarized and analyzed by optically polarized ^{3}He neutron spin filters. The efficiency of the spin rotator was measured at LANSCE to be 98.8±0.5% for neutron energies from 3 to 20 meV over the full phase space of the beam. Systematic effects that the rf spin rotator introduces to the NPDGamma experiment are considered.

  15. Radiochemical Means of Investigating Delayed Neutron Precursors

    International Nuclear Information System (INIS)

    Marmol, P. del

    1968-01-01

    Fast radiochemical methods used now for the determination of delayed neutron precursors are classified and reviewed: precipitations, solvent extractions, range experiments, milking, gas sweeping, isotopic and ion exchange, hot atom reactions and diffusion loss. Advantages and limitations of irradiation systems with respect to fast separations are discussed: external beams which allow faster separations only have low neutron fluxes, internal beams which are mostly fit for gaseous reactions; and rabbits for solution irradiations. Future prospects of radiochemical procedures are presented; among these, studies should be mostly oriented towards gaseous reactions which offer possibilities of isolating very short-lived delayed neutron precursors. Chemical procedures for delayed neutron precursor detection are compared with mass spectrometric and isotope separator techniques; it is concluded that the methods are complementary. (author)

  16. Radiochemical Means of Investigating Delayed Neutron Precursors

    International Nuclear Information System (INIS)

    Marmol, P. del

    1968-01-01

    Fast radiochemical methods used now for the determination of delayed neutron precursors are classified and reviewed: precipitations, solvent extractions, range experiments, milking, gas sweeping, isotopic and ion exchange, hot-atom reactions and diffusion loss. Advantages and limitations of irradiation systems with respect to fast separations are discussed: external beams which allow faster separations only have low neutron fluxes, internal beams which are mostly fit for gaseous reactions; and rabbits for solution irradiations. Future prospects of radiochemical procedures are presented; among these, studies should be mostly oriented towards gaseous reactions which offer possibilities of isolating very short-lived delayed neutron precursors. Chemical procedures for delayed neutron precursor detection are compared with mass spectrometric and isotope-separator techniques; it is concluded that the methods are complementary. (author)

  17. Deuteron beam interaction with Li jet for a neutron source test facility

    International Nuclear Information System (INIS)

    Hassanein, A.

    1995-09-01

    Testing and evaluating candidate fusion reactor materials in a high-flux, high-energy neutron environment are critical to the success and economic feasibility of a fusion device. The current understanding of materials behavior in fission-like environments and existing fusion facilities is insufficient to ensure the necessary performance of future fusion reactor components. An accelerator-based deuterium-lithium system to generate the required high neutron flux for material testing is considered to be the most promising approach in the near future. In this system, a high-energy (30-40 MeV) deuteron beam impinges on a high-speed (10-20 m/s) lithium jet to produce the high-energy (>14 MeV) neutrons required to simulate a fusion environment via the Li (d,n) nuclear stripping reaction. Interaction of the high-energy deuteron beam and the subsequent response of the high-speed lithium jet are evaluated in detail. Deposition of the deuteron beam, jet-thermal hydraulic response, lithium-surface vaporization rate, and dynamic stability of the jet are modeled. It is found that lower beam kinetic energies produce higher surface temperature and consequently higher Li vaporization rates. Larger beam sizes significantly reduce both bulk and surface temperatures. Thermal expansion and dynamic velocities (normal to jet direction) due to beam energy deposition and momentum transfer are much lower than jet flow velocity and decrease substantially at lower beam current densities

  18. Deuteron beam interaction with lithium jet in a neutron source test facility

    International Nuclear Information System (INIS)

    Hassanein, A.

    1996-01-01

    Testing and evaluating candidate fusion reactor materials in a high-flux, high-energy neutron environment are critical to the success and economic feasibility of a fusion device. The current understanding of materials behavior in fission-like environments and existing fusion facilities is insufficient to ensure the necessary performance of future fusion reactor components. An accelerator-based deuterium-lithium system to generate the required high neutron flux for material testing is considered to be the most promising approach in the near future. In this system, a high-energy (30-40 MeV) deuteron beam impinges on a high-speed (10-20 m/s) lithium jet to produce the high-energy (≥14 MeV) neutrons required to simulate a fusion environment via the Li (d,n) nuclear stripping reaction. Interaction of the high-energy deuteron beam and the subsequent response of the high-speed lithium jet are evaluated in detail. Deposition of the deuteron beam, jet-thermal hydraulic response, lithium-surface vaporization rate, and dynamic stability of the jet are modeled. It is found that lower beam kinetic energies produce higher surface temperature and consequently higher Li vaporization rates. Larger beam sizes significantly reduce both bulk and surface temperatures. Thermal expansion and dynamic velocities (normal to jet direction) due to beam energy deposition and momentum transfer are much lower than jet flow velocity and decrease substantially at lower beam current densities. (orig.)

  19. Neutron time behavior for deuterium neutral beam injection into a hydrogen plasma in ORMAK

    International Nuclear Information System (INIS)

    England, A.C.; Howe, H.C.; Mihalczo, J.T.; Fowler, R.H.

    1977-10-01

    Neutrons were produced by D-D interactions when a 28-keV deuterium beam was coinjected into a hydrogen plasma in the Oak Ridge Tokamak (ORMAK). Fokker-Planck calculations, which correctly predict the time behavior of the neutron rate after beam turnon, show that the majority of the neutrons are from injected particles interacting with previously injected deuterons that have scattered to pitch angles of approximately 60 to 90 0 while slowing down

  20. External-beam PIXE analysis of small sculptures

    International Nuclear Information System (INIS)

    Gyodi, I.; Demeter, I.; Hollos-Nagy, K.; Kovacs, I.; Szokefalvi-Nagy, Z.

    1999-01-01

    Non-destructive analysis of precious art objects is an important tool to solve provenance problems or to facilitate restoration. External beam PIXE analysis is one of the most powerful and popular methods used in this respect. The paper summarises the external beam PIXE set-up at the Accelerator Laboratory in Budapest, and two selected applications are described. Different parts of a small Cambodian metal sculpture probably made in the 11th century were analysed. It was observed that the sculpture was composed of an iron core and an outer bronze shell. This sculptural technique was well known in the Middle-East but no indication has been found about its use in the Far-East, yet. Before its restoration paint traces on a wooden relief of St. Jerome made by an unknown artist in about 1600 were analysed. Different white and red paints were distinguished at selected points and the presence of titanium on a certain part of the relief was attributed to a repainting in modern times

  1. Neutron beam effects on spin-exchange-polarized 3He.

    Science.gov (United States)

    Sharma, M; Babcock, E; Andersen, K H; Barrón-Palos, L; Becker, M; Boag, S; Chen, W C; Chupp, T E; Danagoulian, A; Gentile, T R; Klein, A; Penttila, S; Petoukhov, A; Soldner, T; Tardiff, E R; Walker, T G; Wilburn, W S

    2008-08-22

    We have observed depolarization effects when high intensity cold neutron beams are incident on alkali-metal spin-exchange-polarized 3He cells used as neutron spin filters. This was first observed as a reduction of the maximum attainable 3He polarization and was attributed to a decrease of alkali-metal polarization, which led us to directly measure alkali-metal polarization and spin relaxation over a range of neutron fluxes at Los Alamos Neutron Science Center and Institute Laue-Langevin. The data reveal a new alkali-metal spin-relaxation mechanism that approximately scales as sqrt[phi_{n}], where phi_{n} is the neutron capture-flux density incident on the cell. This is consistent with an effect proportional to the concentration of electron-ion pairs but is much larger than expected from earlier work.

  2. Development of advanced neutron beam technology

    Energy Technology Data Exchange (ETDEWEB)

    Seong, B S; Lee, J S; Sim, C M [and others

    2007-06-15

    The purpose of this work is to timely support the national science and technology policy through development of the advanced application techniques for neutron spectrometers, built in the previous project, in order to improve the neutron spectrometer techniques up to the world-class level in both quantity and quality and to reinforce industrial competitiveness. The importance of the research and development (R and D) is as follows: 1. Technological aspects - Development of a high value-added technology through performing the advanced R and D in the broad research areas from basic to applied science and from hard to soft condensed matter using neutron scattering technique. - Achievement of an important role in development of the new technology for the following industries aerospace, defense industry, atomic energy, hydrogen fuel cell etc. by the non-destructive inspection and analysis using neutron radiography. - Development of a system supporting the academic-industry users for the HANARO facility 2. Economical and Industrial Aspects - Essential technology in the industrial application of neutron spectrometer, in the basic and applied research of the diverse materials sciences, and in NT, BT, and IT areas - Broad impact on the economics and the domestic and international collaborative research by using the neutron instruments in the mega-scale research facility, HANARO, that is a unique source of neutron in Korea. 3. Social Aspects - Creating the scientific knowledge and contributing to the advanced industrial society through the neutron beam application - Improving quality of life and building a national consensus on the application of nuclear power by developing the RT fusion technology using the HANARO facility. - Widening the national research area and strengthening the national R and D capability by performing advanced R and D using the HANARO facility.

  3. Development of advanced neutron beam technology

    International Nuclear Information System (INIS)

    Seong, B. S.; Lee, J. S.; Sim, C. M.

    2007-06-01

    The purpose of this work is to timely support the national science and technology policy through development of the advanced application techniques for neutron spectrometers, built in the previous project, in order to improve the neutron spectrometer techniques up to the world-class level in both quantity and quality and to reinforce industrial competitiveness. The importance of the research and development (R and D) is as follows: 1. Technological aspects - Development of a high value-added technology through performing the advanced R and D in the broad research areas from basic to applied science and from hard to soft condensed matter using neutron scattering technique. - Achievement of an important role in development of the new technology for the following industries aerospace, defense industry, atomic energy, hydrogen fuel cell etc. by the non-destructive inspection and analysis using neutron radiography. - Development of a system supporting the academic-industry users for the HANARO facility 2. Economical and Industrial Aspects - Essential technology in the industrial application of neutron spectrometer, in the basic and applied research of the diverse materials sciences, and in NT, BT, and IT areas - Broad impact on the economics and the domestic and international collaborative research by using the neutron instruments in the mega-scale research facility, HANARO, that is a unique source of neutron in Korea. 3. Social Aspects - Creating the scientific knowledge and contributing to the advanced industrial society through the neutron beam application - Improving quality of life and building a national consensus on the application of nuclear power by developing the RT fusion technology using the HANARO facility. - Widening the national research area and strengthening the national R and D capability by performing advanced R and D using the HANARO facility

  4. Expanding options in radiation oncology: neutron beam therapy

    International Nuclear Information System (INIS)

    Cohen, L.

    1982-01-01

    Twelve years experience with neutron beam therapy in Britain, the USA, Europe and Japan shows that local control is achievable in late-stage epidermoid cancer somewhat more frequently than with conventional radiotherapy. Tumours reputed to be radioresistant (salivary gland, bladder, rectosigmoid, melanoma, bone and soft-tissue sarcomas) have proved to be particularly responsive to neutrons. Pilot studies in brain and pancreatic tumours suggest promising new approaches to management of cancer in these sites. The availability of neutron therapy in the clinical environment opens new prospects for irradiation of 'radioresistant' tumours, permits more conservative cancer surgery, expands the use of elective chemotherapy and provides a wider range of options for cancer patients. (author)

  5. The development of maple technology for materials testing, isotope production, and neutron-beam applications

    International Nuclear Information System (INIS)

    Lidstone, R.F.; Gillespie, G.E.; Lee, A.G.; Bishop, W.E.

    1996-01-01

    AECL has been developing MAPLE technology to meet Canadian and international requirements for high-performance research reactors. MAPLE refers to a family of open-tank-in-pool reactors that employ compact H 2 O-cooled cores within D 2 O vessels to efficiently furnish neutrons to various types of irradiation facilities. The initial focus was on a 10-MW t Canadian facility for radioisotope production, the HANARO multipurpose-reactor project, and an associated R and D program. Recently, AECL began to develop the concept for a new Canadian Irradiation Research Facility (IRF) which will support the continued evolution of CANDU (CANadian Deuterium Uranium) technology and generate neutrons for basic and applied materials science. Additionally, AECL is currently developing a standardized MAPLE research-centre design with integrated neutron-application facilities; various reactor-core options have been optimized for different combinations of utilization: a 19-site core for neutron-beam applications and ancillary isotope production, a 31-site core for multipurpose materials testing and neutron-beam applications, and twin 18-site cores for high-flux neutron-beam applications. (author)

  6. Neutron flux determination at the IPR-R1 Triga Mark I neutron beam extractor

    International Nuclear Information System (INIS)

    Zangirolami, Dante Marco; Maretti Junior, Fausto; Ferreira, Andrea Vidal

    2009-01-01

    The IPR-R1 Triga Mark I Reactor located at the CDTN/CNEN, Belo Horizonte, Brazil, has been operating since November of 1960. In this work, measurements of thermal and epithermal neutron flux along the IPR-R1 neutron beam extractor were performed by neutron activation of reference materials using the two foils method. The obtained results were compared with results from two previous works: an experimental measurement done in a previous reactor core configuration and a numerical work made by Monte Carlo simulation using the actual reactor core configuration. The main purpose of this work is to update the measured data to the actual reactor core configuration. (author)

  7. Neutron beam testing of triblades

    Energy Technology Data Exchange (ETDEWEB)

    Michalak, Sarah E [Los Alamos National Laboratory; Du Bois, Andrew J [Los Alamos National Laboratory; Storlie, Curtis B [Los Alamos National Laboratory; Rust, William N [Los Alamos National Laboratory; Du Bois, David H [Los Alamos National Laboratory; Modl, David G [Los Alamos National Laboratory; Quinn, Heather M [Los Alamos National Laboratory; Blanchard, Sean P [Los Alamos National Laboratory; Manuzzato, Andrea [UNIV DEGLI STUDI DI PADOVA ITALY

    2010-12-16

    Four IBM Triblades were tested in the Irradiation of Chips and Electronics facility at the Los Alamos Neutron Science Center. Triblades include two dual-core Opteron processors and four PowerXCell 8i (Cell) processors. The Triblades were tested in their field configuration while running different applications, with the beam aimed at the Cell processor or the Opteron running the application. Testing focused on the Cell processors, which were tested while running five different applications and an idle condition. While neither application nor Triblade was statistically important in predicting the hazard rate, the hazard rate when the beam was aimed at the Opterons was significantly higher than when it was aimed at the Cell processors. In addition, four Cell blades (one in each Triblade) suffered voltage shorts, leading to their inoperability. The hardware tested is the same as that in the Roadrunner supercomputer.

  8. Floppy disc units for data collection from neutron beam experiments

    International Nuclear Information System (INIS)

    Hall, J.W.

    1976-02-01

    The replacement of paper tape output facilities on neutron beam equipment on DIDO and PLUTO reactors by floppy discs will improve reliability and provide a more manageable data storage medium. The cost of floppy disc drives is about the same as a tape punch and printer and less than other devices such as a magnetic tape. Suitable floppy disc controllers are not at present available and a unit was designed as a directly pluggable replacement for paper tape punches. This design was taken as the basis in the development of a prototype unit for use in neutron beam equipment. The circuit operation for this prototype unit is described. (author)

  9. Possibilities and conditions of applying PIXE analysis with external proton beam

    International Nuclear Information System (INIS)

    Potocek, V.

    1989-01-01

    The technical and methodological prerequisites are summed up for the use of the PIXE method with an external proton beam. The method is suitable for the preliminary analysis of unknown samples prior to the choice of the best suited analytical method, for the nondestructive analysis of rare samples such as unique works of art, of small amounts of materials which are difficult to access, etc., as well as for calibration and comparing analyses. As for the operators the application of the PIXE method with external proton beam assumes the availability of accelerator operating time, minimization of the length of exposure of the targets, optimization of parameters of the exciting beam and automation of the whole process. Attention is also devoted to technical provisions and organization of laboratory work. The design is described of an analytical unit using the PIXE method with external proton beam, and it is stated that the Van de Graaff accelerator at the Institute of Nuclear Physics in Rez near Prague could be used for the purpose. (Z.M.). 6 refs

  10. Influence of core model parameters on the characteristics of neutron beams of the research reactor

    Directory of Open Access Journals (Sweden)

    N. A. Khafizova

    2013-12-01

    Full Text Available IRT MEPhI reactor is equipped with a number of facilities at horizontal experimental channels (HEC. Knowing of parameters influencing spatio-angular distribution of irradiation fields is essential for each application area. The research for neutron capture therapy (NCT facility at HEC of the reactor was made. Calculation methods have been used to estimate how the reactor core parameters influence neutron beam characteristics at the HEC output. The impact of neutron source model in Monte Carlo calculations by MCNP code on the parameters of neutron and secondary photon field at the output of irradiation beam tubes of research reactor is estimated. The study shows that specifying neutron source with fission reaction rate distribution in SDEF option gives almost the same results as criticality calculation considered the most accurate. Our calculations show that changes of the core operational parameters have insignificant influence on characteristics of neutron beams at HEC output.

  11. Neutron-induced damage evolution under Beam Raster Scanner conditions for IFMIF

    International Nuclear Information System (INIS)

    Mota, Fernando; Ortiz, Christophe J.; Ibarra, Angel; Vila, Rafael

    2011-01-01

    The formation and evolution of defects in materials irradiated with a homogeneous neutron source and with the Beam Raster Scanner (BRS) solution was investigated. The intensity neutron source fluctuations inherent to the BRS system were determined using the neutron transport McDeLicious code. Defects generated during irradiation were calculated using the binary collision approximation MARLOWE code, using the primary knock-on atom (PKA) energy spectrum resulting from neutron interactions with the material. In order to predict the evolution of defects during irradiation, a Rate Theory model based on ab initio parameters was developed. Our model accounts for the migration of mobile defects, the formation of clusters and their recombination. As an example, we investigated defect evolution in Fe irradiated at room temperature in both beam configurations. Simulation results clearly indicate that the defect evolution expected in the BRS configuration is nearly the same as the one expected in a homogeneous irradiation system.

  12. A facility to produce collimated neutron beams at the Legnaro Laboratories

    International Nuclear Information System (INIS)

    Colautti, P.; Talpo, G.; Tornielli, G.

    1988-01-01

    The 7 MV Van de Graaff and the 16 MV Tandem accelerators at the Legnaro National Laboratories can be used to produce fast neutron fluxes of moderate intensity, ranging in energy from 1 MeV to 50 MeV. A W-polyethylene-Pb cylindrical collimator has been constructed in order to produce a collimated neutron beam, with well defined dose and microdose characteristics for radiobiological experiments. The collimator can be assembled in different configurations allowing both for different thicknesses and different beam apertures. Dosimetric measurements have been made with a d(4.5)+Be source. These demonstrate sharp beam edges with attenuation behind the shield of 20% with the 15 cm collimator and 1.5% with the 50 cm collimator. (author)

  13. Feasibility of sealed D-T neutron generator as neutron source for liver BNCT and its beam shaping assembly.

    Science.gov (United States)

    Liu, Zheng; Li, Gang; Liu, Linmao

    2014-04-01

    This paper involves the feasibility of boron neutron capture therapy (BNCT) for liver tumor with four sealed neutron generators as neutron source. Two generators are placed on each side of the liver. The high energy of these emitted neutrons should be reduced by designing a beam shaping assembly (BSA) to make them useable for BNCT. However, the neutron flux decreases as neutrons pass through different materials of BSA. Therefore, it is essential to find ways to increase the neutron flux. In this paper, the feasibility of using low enrichment uranium as a neutron multiplier is investigated to increase the number of neutrons emitted from D-T neutron generators. The neutron spectrum related to our system has a proper epithermal flux, and the fast and thermal neutron fluxes comply with the IAEA recommended values. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Two-stream instability for a light ion beam-plasma system with external magnetic field

    International Nuclear Information System (INIS)

    Okada, T.; Tazawa, H.

    1992-12-01

    For inertial confinement fusion, a focused light ion beam (LIB) is required to propagate stably through a chamber to a target. We have pointed out that the applied external magnetic field is important for LIB propagation. To investigate the influence of the external magnetic field on the LIB propagation, we analysed the electrostatic dispersion relation of magnetized light ion beam-plasma system. The particle in-cell (PIC) simulation results are presented for a light ion beam-plasma system with external magnetic field. (author)

  15. External proton and Li beams

    International Nuclear Information System (INIS)

    Schuff, Juan A.; Burlon, Alejandro A.; Debray, Mario E.; Kesque, Jose M.; Kreiner, Andres J.; Stoliar, Pablo A.; Naab, Fabian; Ozafran, Mabel J.; Vazquez, Monica E.; Perez de la Hoz, A.; Somacal, Hector; Valda, Alejandro; Canevas, S.; Ruffolo, M.; Tasat, D.R.; Muhlmann, M. C.

    2000-01-01

    In the frame of a feasibility study to introduce proton therapy in Argentina in a collaborative agreement between the Physics and Radiobiology Departments of the National Atomic Energy Commission or Argentina and the Centre de Protontherapie de Orsay, France, external proton and Li beams were produced at the TANDAR accelerator in Buenos Aires. The specific aim of this work was to start radiobiology studies on cell cultures and small laboratory animals. In particular we seek to determine here the relative biological effectiveness, RBE, for proton and Li beams as a function of energy for different tumor and normal cell lines. The 24 MeV proton beam was diffused using a 25 μm gold foil and extracted through a Kapton window to obtain a homogeneous field (constant to 95%) of about 7 cm in diameter. Measurements were carried out with quasi-monoenergetic beams (of 20.2 ± 0.07 MeV, 2.9 ± 0.10 MeV y 1.5 ± 0.1 MeV for protons and 21.4 ± 0.4 MeV for Lithium). Proton fluence and Bragg peaks were measured. The dose delivered in each case was monitored on-line with a calibrated transmission ionization chamber. Three cell lines PDV, PDVC 57 and V 79 (as a reference) were irradiated with γ-rays, proton and lithium beams with linear energy transfer (LET) from 2 to 100 keV/μm. RBE values in the range of 1.2-5.9 were obtained. In addition preliminary studies on chromosomal aberrations and viability of alveolar macrophages were carried out. (author)

  16. 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.

  17. Induction of external abnormalities in offspring of male mice irradiated with 252Cf neutron

    International Nuclear Information System (INIS)

    Kurishita, Akihiro; Ono, Tetsuya; Mori, Yuriko; Okada, Shigefumi; Sawada, Syozo

    1992-01-01

    To assess the genetic effects of fission neutron, the induction of external malformations was studied in F 1 fetuses after F 0 male mice were irradiated. Male mice of the ICR:MCH strain were irradiated with 252 Cf neutron at doses of 0.238, 0.475, 0.95 and 1.9 Gy. They were mated with non-irradiated female mice at 71-120 days after irradiation. Pregnant females were autopsied on day 18 of gestation and their fetuses were examined for deaths and external abnormalities. No increases of pre- and post-implantation losses were noted at any dose. External abnormalities were observed at rates of 1.40% in the 0.238 Gy, 2.23% in the 0.475 Gy, 3.36% in the 0.95 and 3.26% in the 1.9 Gy groups; the rate in the control group was 1.65%. The dose-response curve was linear up to 0.95 Gy, and then flattened out; the induction rate of external abnormalities was 2.7x10 -4 /gamete/cGy based on the linear regression. These results indicated that fission neutron effectively induces external abnormalities in F 1 fetuses after spermatogonial irradiation. (author). 29 refs.; 1 fig.; 2 tabs

  18. Possibility of a crossed-beam experiment involving slow-neutron capture by unstable nuclei - ``rapid-process tron''

    Science.gov (United States)

    Yamazaki, T.; Katayama, I.; Uwamino, Y.

    1993-02-01

    The possibility of a crossed beam facility of slow neutrons capturing unstable nuclei is examined in connection with the Japanese Hadron Project. With a pulsed proton beam of 50 Hz repetition and with a 100 μA average beam current, one obtains a spallation neutron source of 2.4 × 10 8 thermal neutrons/cm 3/spill over a 60 cm length with a 3 ms average duration time by using a D 2O moderator. By confining radioactive nuclei of 10 9 ions in a beam circulation ring of 0.3 MHz revolution frequency, so that nuclei pass through the neutron source, one obtains a collision luminosity of 3.9 × 10 24/cm 2/s. A new research domain aimed at studying rapid processes in nuclear genetics in a laboratory will be created.

  19. Out‐of‐field doses and neutron dose equivalents for electron beams from modern Varian and Elekta linear accelerators

    Science.gov (United States)

    Cardenas, Carlos E.; Nitsch, Paige L.; Kudchadker, Rajat J.; Howell, Rebecca M.

    2016-01-01

    Out‐of‐field doses from radiotherapy can cause harmful side effects or eventually lead to secondary cancers. Scattered doses outside the applicator field, neutron source strength values, and neutron dose equivalents have not been broadly investigated for high‐energy electron beams. To better understand the extent of these exposures, we measured out‐of‐field dose characteristics of electron applicators for high‐energy electron beams on two Varian 21iXs, a Varian TrueBeam, and an Elekta Versa HD operating at various energy levels. Out‐of‐field dose profiles and percent depth‐dose curves were measured in a Wellhofer water phantom using a Farmer ion chamber. Neutron dose was assessed using a combination of moderator buckets and gold activation foils placed on the treatment couch at various locations in the patient plane on both the Varian 21iX and Elekta Versa HD linear accelerators. Our findings showed that out‐of‐field electron doses were highest for the highest electron energies. These doses typically decreased with increasing distance from the field edge but showed substantial increases over some distance ranges. The Elekta linear accelerator had higher electron out‐of‐field doses than the Varian units examined, and the Elekta dose profiles exhibited a second dose peak about 20 to 30 cm from central‐axis, which was found to be higher than typical out‐of‐field doses from photon beams. Electron doses decreased sharply with depth before becoming nearly constant; the dose was found to decrease to a depth of approximately E(MeV)/4 in cm. With respect to neutron dosimetry, Q values and neutron dose equivalents increased with electron beam energy. Neutron contamination from electron beams was found to be much lower than that from photon beams. Even though the neutron dose equivalent for electron beams represented a small portion of neutron doses observed under photon beams, neutron doses from electron beams may need to be considered for

  20. Out-of-field doses and neutron dose equivalents for electron beams from modern Varian and Elekta linear accelerators.

    Science.gov (United States)

    Cardenas, Carlos E; Nitsch, Paige L; Kudchadker, Rajat J; Howell, Rebecca M; Kry, Stephen F

    2016-07-08

    Out-of-field doses from radiotherapy can cause harmful side effects or eventually lead to secondary cancers. Scattered doses outside the applicator field, neutron source strength values, and neutron dose equivalents have not been broadly investigated for high-energy electron beams. To better understand the extent of these exposures, we measured out-of-field dose characteristics of electron applicators for high-energy electron beams on two Varian 21iXs, a Varian TrueBeam, and an Elekta Versa HD operating at various energy levels. Out-of-field dose profiles and percent depth-dose curves were measured in a Wellhofer water phantom using a Farmer ion chamber. Neutron dose was assessed using a combination of moderator buckets and gold activation foils placed on the treatment couch at various locations in the patient plane on both the Varian 21iX and Elekta Versa HD linear accelerators. Our findings showed that out-of-field electron doses were highest for the highest electron energies. These doses typically decreased with increasing distance from the field edge but showed substantial increases over some distance ranges. The Elekta linear accelerator had higher electron out-of-field doses than the Varian units examined, and the Elekta dose profiles exhibited a second dose peak about 20 to 30 cm from central-axis, which was found to be higher than typical out-of-field doses from photon beams. Electron doses decreased sharply with depth before becoming nearly constant; the dose was found to decrease to a depth of approximately E(MeV)/4 in cm. With respect to neutron dosimetry, Q values and neutron dose equivalents increased with electron beam energy. Neutron contamination from electron beams was found to be much lower than that from photon beams. Even though the neutron dose equivalent for electron beams represented a small portion of neutron doses observed under photon beams, neutron doses from electron beams may need to be considered for special cases.

  1. Genetic Algorithms: A New Method for Neutron Beam Spectral Characterization

    International Nuclear Information System (INIS)

    David W. Freeman

    2000-01-01

    A revolutionary new concept for solving the neutron spectrum unfolding problem using genetic algorithms (GAs) has recently been introduced. GAs are part of a new field of evolutionary solution techniques that mimic living systems with computer-simulated chromosome solutions that mate, mutate, and evolve to create improved solutions. The original motivation for the research was to improve spectral characterization of neutron beams associated with boron neutron capture therapy (BNCT). The GA unfolding technique has been successfully applied to problems with moderate energy resolution (up to 47 energy groups). Initial research indicates that the GA unfolding technique may well be superior to popular unfolding methods in common use. Research now under way at Kansas State University is focused on optimizing the unfolding algorithm and expanding its energy resolution to unfold detailed beam spectra based on multiple foil measurements. Indications are that the final code will significantly outperform current, state-of-the-art codes in use by the scientific community

  2. Compendium of Neutron Beam Facilities for High Precision Nuclear Data Measurements. Annex: Individual Reports

    International Nuclear Information System (INIS)

    2014-07-01

    The recent advances in the development of nuclear science and technology, demonstrating the globally growing economy, require highly accurate, powerful simulations and precise analysis of the experimental results. Confidence in these results is still determined by the accuracy of the atomic and nuclear input data. For studying material response, neutron beams produced from accelerators and research reactors in broad energy spectra are reliable and indispensable tools to obtain high accuracy experimental results for neutron induced reactions. The IAEA supports the accomplishment of high precision nuclear data using nuclear facilities in particular, based on particle accelerators and research reactors around the world. Such data are essential for numerous applications in various industries and research institutions, including the safety and economical operation of nuclear power plants, future fusion reactors, nuclear medicine and non-destructive testing technologies. The IAEA organized and coordinated the technical meeting Use of Neutron Beams for High Precision Nuclear Data Measurements, in Budapest, Hungary, 10–14 December 2012. The meeting was attended by participants from 25 Member States and three international organizations — the European Organization for Nuclear Research (CERN), the Joint Research Centre (JRC) and the Organisation for Economic Co-operation and Development (OECD) Nuclear Energy Agency (OECD/NEA). The objectives of the meeting were to provide a forum to exchange existing know-how and to share the practical experiences of neutron beam facilities and associated instrumentation, with regard to the measurement of high precision nuclear data using both accelerators and research reactors. Furthermore, the present status and future developments of worldwide accelerator and research reactor based neutron beam facilities were discussed. This publication is a summary of the technical meeting and additional materials supplied by the international

  3. Study on beam geometry and image reconstruction algorithm in fast neutron computerized tomography at NECTAR facility

    Science.gov (United States)

    Guo, J.; Bücherl, T.; Zou, Y.; Guo, Z.

    2011-09-01

    Investigations on the fast neutron beam geometry for the NECTAR facility are presented. The results of MCNP simulations and experimental measurements of the beam distributions at NECTAR are compared. Boltzmann functions are used to describe the beam profile in the detection plane assuming the area source to be set up of large number of single neutron point sources. An iterative algebraic reconstruction algorithm is developed, realized and verified by both simulated and measured projection data. The feasibility for improved reconstruction in fast neutron computerized tomography at the NECTAR facility is demonstrated.

  4. Study on beam geometry and image reconstruction algorithm in fast neutron computerized tomography at NECTAR facility

    International Nuclear Information System (INIS)

    Guo, J.; Buecherl, T.; Zou, Y.; Guo, Z.

    2011-01-01

    Investigations on the fast neutron beam geometry for the NECTAR facility are presented. The results of MCNP simulations and experimental measurements of the beam distributions at NECTAR are compared. Boltzmann functions are used to describe the beam profile in the detection plane assuming the area source to be set up of large number of single neutron point sources. An iterative algebraic reconstruction algorithm is developed, realized and verified by both simulated and measured projection data. The feasibility for improved reconstruction in fast neutron computerized tomography at the NECTAR facility is demonstrated.

  5. Study on beam geometry and image reconstruction algorithm in fast neutron computerized tomography at NECTAR facility

    Energy Technology Data Exchange (ETDEWEB)

    Guo, J. [State Key Laboratory of Nuclear Physics and Technology and School of Physics, Peking University, 5 Yiheyuan Lu, Beijing 100871 (China); Lehrstuhl fuer Radiochemie, Technische Universitaet Muenchen, Garching 80748 (Germany); Buecherl, T. [Lehrstuhl fuer Radiochemie, Technische Universitaet Muenchen, Garching 80748 (Germany); Zou, Y., E-mail: zouyubin@pku.edu.cn [State Key Laboratory of Nuclear Physics and Technology and School of Physics, Peking University, 5 Yiheyuan Lu, Beijing 100871 (China); Guo, Z. [State Key Laboratory of Nuclear Physics and Technology and School of Physics, Peking University, 5 Yiheyuan Lu, Beijing 100871 (China)

    2011-09-21

    Investigations on the fast neutron beam geometry for the NECTAR facility are presented. The results of MCNP simulations and experimental measurements of the beam distributions at NECTAR are compared. Boltzmann functions are used to describe the beam profile in the detection plane assuming the area source to be set up of large number of single neutron point sources. An iterative algebraic reconstruction algorithm is developed, realized and verified by both simulated and measured projection data. The feasibility for improved reconstruction in fast neutron computerized tomography at the NECTAR facility is demonstrated.

  6. Compact D-D Neutron Source-Driven Subcritical Multiplier and Beam-Shaping Assembly for Boron Neutron Capture Therapy

    International Nuclear Information System (INIS)

    Ganda, Francesco; Vujic, Jasmina; Greenspan, Ehud; Leung, Ka-Ngo

    2010-01-01

    This work assesses the feasibility of using a small, safe, and inexpensive keff 0.98 subcritical fission assembly [subcritical neutron multiplier (SCM)] to amplify the treatment neutron beam intensity attainable from a compact deuterium-deuterium (D-D) fusion neutron source delivering [approximately]1012 n/s. The objective is to reduce the treatment time for deep-seated brain tumors to [approximately]1 h. The paper describes the optimal SCM design and two optimal beam-shaping assemblies (BSAs) - one designed to maximize the dose rate and the other designed to maximize the total dose that can be delivered to a deep-seated tumor. The neutron beam intensity amplification achieved with the optimized SCM and BSA results in an increase in the treatment dose rate by a factor of 18: from 0.56 Gy/h without the SCM to 10.1 Gy/h. The entire SCM is encased in an aluminum structure. The total amount of 20% enriched uranium required for the SCM is 8.5 kg, and the cost (not including fabrication) is estimated to be less than $60,000. The SCM power level is estimated at 400 W when driven by a 1012 n/s D-D neutron source. This translates into consumption of only [approximately]0.6% of the initially loaded 235U atoms during 50 years of continuous operation and implies that the SCM could operate continuously for the entire lifetime of the facility without refueling. Cooling the SCM does not pose a challenge; it may be accomplished by natural circulation as the maximum heat flux is only 0.034 W/cm2.

  7. Reactor beam calculations to determine optimum delivery of epithermal neutrons for treatment of brain tumors

    International Nuclear Information System (INIS)

    Wheeler, F.J.; Nigg, D.W.; Capala, J.

    1997-01-01

    Studies were performed to assess theoretical tumor control probability (TCP) for brain-tumor treatment with boron neutron capture therapy (BNCT) using epithermal neutron sources from reactors. The existing epithermal-neutron beams at the Brookhaven Medical Research Reactor Facility (BMRR), the Petten High Flux Reactor Facility (HWR) and the Finnish Research Reactor 1 (FIR1) have been analyzed and characterized using common analytical and measurement methods allowing for this inter-comparison. Each of these three facilities is unique and each offers an advantage in some aspect of BNCT, but none of these existing facilities excel in all neutron-beam attributes as related to BNCT. A comparison is therefore also shown for a near-optimum reactor beam which does not currently exist but which would be feasible with existing technology. This hypothetical beam is designated BNCT-1 and has a spectrum similar to the FIR-1, the mono-directionality of the HFR and the intensity of the BMRR. A beam very similar to the BNCT-1 could perhaps be achieved with modification of the BMRR, HFR, or FIR, and could certainly be realized in a new facility with today's technology

  8. A low background pulsed neutron polyenergetic beam at the ET-RR-1 reactor

    International Nuclear Information System (INIS)

    Adib, M.; Abdel-Kawy, A.; Habib, N.; Abu-El-Ela, M.; Wahba, M.; Kilany, M.

    1991-12-01

    A low background pulsed neutron polyenergetic thermal beam at ET-RR-1 is produced by a rotor and rotating collimator suspended in magnetic fields. Each of them is mounted on its mobile platform and whose centres are 66 cm apart, rotating synchronously at speeds up to 16000 rpm. It was found that the neutron burst produced by the rotor with almost 100% transmission passes through the collimator, when the rotation phase between them is 28.8 deg. Moreover the background level achieved at the detector position is low, constant and free from peaks due to gamma rays and fast neutrons accompanying the reactor thermal beam. (author). 12 refs, 3 figs

  9. A comparison of mutagenic effects of common wheat by electron beam, fast neutron and 60Co gamma ray irradiation

    International Nuclear Information System (INIS)

    An Daochang; Wang Linqing

    1988-02-01

    After winter wheat was irradiated by electron beam, fast neutron and γ-rays, respectively, the RBE value of electron beam to both fast neutrons and γ-rays was less than one, the RBE value of fast neutron to γ-rays was largely more than one. This results indicated that biological effect of M 1 generation induced by electron beam was less than that of fast neutrons very much, and similar to γ-ray irradiation. With electron beam irradiation, the half-lethal doses of M 1 generation were from 185 to 370 Gy, closer to 370 Gy, the lethal doses from 740 to 925 Gy. M 2 mutation efficiency with electron beam treatment was larger as compared with that with both fast neutrons and γ-rays. A wider mutation spectrum and higher mutation efficiency compared with other physical mutagens can be obtained with electron beam irradiation, about 30% higher than that with γ-ray irradiation. The best doses of irradiation with electron beam were 370 to 555 Gy. Fast neutrons, a better dose of which was 25 Gy, could induce more mutants than that with γ-rays in M 2 generation. The dose in which biological injury reached to 50% was the best dose for M 2 mutants by electron beam irradiation

  10. Proceedings of the 5. symposium on neutron dosimetry. Beam dosimetry

    International Nuclear Information System (INIS)

    Schraube, H.; Burger, G.; Booz, J.

    1985-01-01

    Proceedings of the fifth symposium on neutron dosimetry, organized at Neuherberg, 17-21 September 1984, by the Commission of the European Communities and the GSF Neuherberg, with the co-sponsorship of the US Department of Energy, Office of Health and Environmental Research. The proceedings deal with research on concepts, instruments and methods in radiological protection for neutrons and mixed neutron-gamma fields, including the generation, collection and evaluation of new dosimetric data, the derivation of relevant radiation protection quantitites, and the harmonization of experimental methods and instrumentation by intercomparison programmes. Besides radiation protection monitoring, the proceedings also report on the improvement of neutron beam dosimetry in the fields of radiobiology and radiation therapy

  11. Survey on neutron production by electron beam from high power CW electron linear accelerator

    International Nuclear Information System (INIS)

    Toyama, S.

    1999-04-01

    In Japan Nuclear Cycle Development Institute, the development of high current CW electron linear accelerator is in progress. It is possible for an accelerator to produce neutrons by means of a spallation and photo nuclear reactions. Application of neutron beam produced by bremsstrahlung is one of ways of the utilization for high current electron accelerator. It is actual that many electron linear accelerators which maximum energy is higher than a few hundreds MeV are used as neutron sources. In this report, an estimate of neutron production is evaluated for high current CW electron linear accelerator. The estimate is carried out by 10 MeV beam which is maximum energy limited from the regulation and rather low for neutron production. Therefore, the estimate is also done by 17 and 35 MeV beam which is possible to be accelerated. Beryllium is considered as a target for lower electron energy in addition to Lead target for higher energy, because Beryllium has low threshold energy for neutron production. The evaluation is carried out in account of the target thickness optimized by the radiation length and neutron cross section reducing the energy loss for both of electron and neutron, so as to get the maximum number of neutrons. The result of the calculations shows neutron numbers 1.9 x 10 10 , 6.1 x 10 13 and 4.8 x 10 13 (n/s), respectively, for 10, 17, and 35 MeV with low duty. The thermal removal from the target is one of critical points. The additional shielding and cooling system is necessary in order to endure radiation. A comparison with other facilities are also carried out. The estimate of neutron numbers suggests the possibility to be applied for neutron radiography and measurement of nuclear data by means of Lead spectrometer, for example. (author)

  12. Effect of Neutron Irradiation on Beam-Column Interaction of Reinforced Concrete

    International Nuclear Information System (INIS)

    Kwon, Tae-Hyun; Park, Jiho; Kim, Jun Yeon; Kim, HyungTae; Park, Kyoungsoo; Kim, Sang-Ho

    2015-01-01

    Age-related effects on such RC structures have been extensively studied in detail. However, the effect of neutron irradiation requires further studies from its limited database. Most of RC structures have been regarded as sound as the neutron fluence below 1.0x10 19 n/cm 2 . The reduction of strength is not considered in a periodic inspection program at aging NPPs. However, RC structures, such as biological shields and supports for a reactor vessel, could be exposed to see the critical level of neutron fluence at years of operation. In this regard, beam-column interaction of a typical RC member is numerically investigated as a result of neutron irradiation. The effect of neutron irradiation on beam-column interaction is evaluated. ACI318 requires the strength reduction factor, ϕ=0.70, for the compression controlled area and the higher up to 0.9 as the tensile strain in steel reinforcement goes higher. This concept works well with this example. However, this does not take into account the energy dissipation capacity of the member but it only expresses the ultimate strength. Therefore, the current strength evaluation concept may be misleading when the material behavior of steel reinforcement becomes brittle due to the neutron irradiation. In such case, even for the transient and tension controlled area, the strength reduction factor needs to be modified to account for the potential ductility loss

  13. Spallation study with proton beams around 1 GeV: neutron production

    International Nuclear Information System (INIS)

    Boudard, A.; Borne, F.; Brochard, F.; Crespin, S.; Drake, D.; Duchazeaubeneix, J.C.; Durand, D.; Durand, J.M.; Frehaut, J.; Hanappe, F.; Kowalski, L.; Lebrun, C.; Lecolley, F.R.; Lecolley, J.F.; Ledoux, X.; Lefebvres, F.; Legrain, R.; Leray, S.; Louvel, M.; Martinez, E.; Meigo, S.I.; Menard, S.; Milleret, G.; Patin, Y.; Petibon, E.; Plouin, F.; Pras, P.; Schapira, J.P.; Stuttge, L.; Terrien, Y.; Thun, J.; Uematsu, M.; Varignon, C.; Volant, C.; Whittal, D.M.; Wlazlo, W.

    2000-01-01

    Experiments performed at Lab. Nat. SATURNE on neutron produced by spallation from proton beams in the range 0.8 - 1.6 GeV are presented. Experimental data compared with codes show a significant improvement of the recent intra-nuclear cascade (J. Cugnon). This is also true in the same way for the neutron production from thick targets. However the model underestimates the energetic neutrons produced in the backward direction and other quantities as residual nuclei cross sections are not accurately predicted

  14. Systematic error in the precision measurement of the mean wavelength of a nearly monochromatic neutron beam due to geometric errors

    Energy Technology Data Exchange (ETDEWEB)

    Coakley, K.J., E-mail: kevin.coakley@nist.go [National Institute of Standards and Technology, 325 Broadway, Boulder, CO 80305 (United States); Dewey, M.S. [National Institute of Standards and Technology, Gaithersburg, MD (United States); Yue, A.T. [University of Tennessee, Knoxville, TN (United States); Laptev, A.B. [Tulane University, New Orleans, LA (United States)

    2009-12-11

    Many experiments at neutron scattering facilities require nearly monochromatic neutron beams. In such experiments, one must accurately measure the mean wavelength of the beam. We seek to reduce the systematic uncertainty of this measurement to approximately 0.1%. This work is motivated mainly by an effort to improve the measurement of the neutron lifetime determined from data collected in a 2003 in-beam experiment performed at NIST. More specifically, we seek to reduce systematic uncertainty by calibrating the neutron detector used in this lifetime experiment. This calibration requires simultaneous measurement of the responses of both the neutron detector used in the lifetime experiment and an absolute black neutron detector to a highly collimated nearly monochromatic beam of cold neutrons, as well as a separate measurement of the mean wavelength of the neutron beam. The calibration uncertainty will depend on the uncertainty of the measured efficiency of the black neutron detector and the uncertainty of the measured mean wavelength. The mean wavelength of the beam is measured by Bragg diffracting the beam from a nearly perfect silicon analyzer crystal. Given the rocking curve data and knowledge of the directions of the rocking axis and the normal to the scattering planes in the silicon crystal, one determines the mean wavelength of the beam. In practice, the direction of the rocking axis and the normal to the silicon scattering planes are not known exactly. Based on Monte Carlo simulation studies, we quantify systematic uncertainties in the mean wavelength measurement due to these geometric errors. Both theoretical and empirical results are presented and compared.

  15. Epithermal neutron beam design for neutron capture therapy at the Power Burst Facility and the Brookhaven Medical Research Reactor

    International Nuclear Information System (INIS)

    Wheeler, F.J.; Parsons, D.K.; Rushton, B.L.; Nigg, D.W.

    1990-01-01

    Nuclear design studies have been performed for two reactor-based epithermal neutron beams for cancer treatment by neutron capture therapy (NCT). An intermediate-intensity epithermal beam has been designed and implemented at the Brookhaven Medical Research Reactor (BMRR). Measurements show that the BMRR design predictions for the principal characteristics of this beam are accurate. A canine program for research into the biological effects of NCT is now under way at BMRR. The design for a high-intensity epithermal beam with minimal contamination from undesirable radiation components has been finalized for the Power Burst Facility (PBF) at the Idaho National Engineering Laboratory. This design will be implemented when it is determined that human NCT trials are advisable. The PBF beam will exhibit approximately an order of magnitude improvement in absolute epithermal flux intensity over that available in the BMRR, and its angular distribution and spectral characteristics will be more advantageous for NCT. The combined effects of beam intensity, angular distribution, spectrum, and contaminant level allow the desired tumor radiation dose to be delivered in much shorter times than are possible with the currently available BMRR beam, with a significant reduction (factor of 3 to 5) in collateral dose due to beam contaminants

  16. On scaling and optimization of high-intensity, low-beam-loss RF linacs for neutron source drivers

    International Nuclear Information System (INIS)

    Jameson, R.A.

    1992-01-01

    RF linacs providing cw proton beams of 30--250 mA at 800--1600 MeV, and cw deuteron beams of 100--250 mA at 35--40 MeV, are needed as drivers for factory neutron sources applied to radioactive waste transmutation, advanced energy production, materials testing facilities, and spallation neutron sources. The maintenance goals require very low beam loss along the linac. Optimization of such systems is complex; status of beam dynamics aspects presently being investigated is outlined

  17. Multipurpose epithermal neutron beam on new research station at MARIA research reactor in Swierk-Poland

    Energy Technology Data Exchange (ETDEWEB)

    Gryzinski, M.A.; Maciak, M. [National Centre for Nuclear Research, Andrzeja Soltana 7, 05-400 Otwock-Swierk (Poland)

    2015-07-01

    MARIA reactor is an open-pool research reactor what gives the chance to install uranium fission converter on the periphery of the core. It could be installed far enough not to induce reactivity of the core but close enough to produce high flux of fast neutrons. Special design of the converter is now under construction. It is planned to set the research stand based on such uranium converter in the near future: in 2015 MARIA reactor infrastructure should be ready (preparation started in 2013), in 2016 the neutron beam starts and in 2017 opening the stand for material and biological research or for medical training concerning BNCT. Unused for many years, horizontal channel number H2 at MARIA research rector in Poland, is going to be prepared as a part of unique stand. The characteristics of the neutron beam will be significant advantage of the facility. High flux of neutrons at the level of 2x10{sup 9} cm{sup -2}s{sup -1} will be obtainable by uranium neutron converter located 90 cm far from the reactor core fuel elements (still inside reactor core basket between so called core reflectors). Due to reaction of core neutrons with converter U{sub 3}Si{sub 2} material it will produce high flux of fast neutrons. After conversion neutrons will be collimated and moderated in the channel by special set of filters and moderators. At the end of H2 channel i.e. at the entrance to the research room neutron energy will be in the epithermal energy range with neutron intensity at least at the level required for BNCT (2x10{sup 9} cm{sup -2}s{sup -1}). For other purposes density of the neutron flux could be smaller. The possibility to change type and amount of installed filters/moderators which enables getting different properties of the beam (neutron energy spectrum, neutron-gamma ratio and beam profile and shape) is taken into account. H2 channel is located in separate room which is adjacent to two other empty rooms under the preparation for research laboratories (200 m2). It is

  18. Response of LET spectrometer based on track etching at some neutron sources

    International Nuclear Information System (INIS)

    Spurny, Frantisek; Brabcova, Katerina; Jadrnickova, Iva

    2008-01-01

    There is still need to develop upgrade, and test further methods able to characterise the external exposure to neutrons. This contribution presents further results obtained with the goal to enlarge and upgrade the possibility of neutron dosimetry and microdosimetry with a LET spectrometer based on the chemically etched track detectors (TED). As TED we have used several types of polyallyldiglycolcarbonates (PADC). The PADC detectors have been exposed in: high energy neutron beams at iThemba facility, Cape Town, South Africa, and in monoenergetic neutron beams at JRC Geel, Belgium. The studies have been performed in the frame of the ESA supported project DOBIES. (author)

  19. Neutron production and dose rate in the IFMIF/EVEDA LIPAc injector beam commissioning

    Energy Technology Data Exchange (ETDEWEB)

    Kondo, Keitaro, E-mail: kondo.keitaro@jaea.go.jp [Rokkasho Fusion Institute, Japan Atomic Energy Agency, Rokkasho-mura, Kamikita-gun, Aomori (Japan); Narita, Takahiro; Usami, Hiroki; Takahashi, Hiroki; Ochiai, Kentaro; Shinto, Katsuhiro; Kasugai, Atsushi [Rokkasho Fusion Institute, Japan Atomic Energy Agency, Rokkasho-mura, Kamikita-gun, Aomori (Japan); Okumura, Yoshikazu [IFMIF/EVEDA Project Team, Rokkasho-mura, Kamikita-gun, Aomori (Japan)

    2016-11-01

    Highlights: • A dedicated neutron production yield monitoring system for LIPAc has been developed. • The biological dose rate during operation of the LIPAc injector was analyzed. • The neutron streaming effect due to penetrations in the shielding wall was investigated. - Abstract: The construction of the Linear IFMIF Prototype Accelerator (LIPAc) is in progress in Rokkasho, Japan, and the deuteron beam commissioning of the injector began in July 2015. Due to the huge beam current of 125 mA, a large amount of d-D neutrons are produced in the commissioning. The neutron streaming effect through pipe penetrations and underground pits may dominate the radiation dose at the outside of the accelerator vault during the injector operation. In the present study the effective dose rate expected during the injector commissioning was analyzed by a Monte Carlo calculation and compared with the measured value. For the comparison it is necessary to know the total neutron production yield in the accelerator vault, thus a dedicated neutron production yield monitoring system was developed. The yield obtained was smaller than that previously reported in a literature by a factor of a few and seems to depend on some beam conditions. From the comparison it was proved that the calculation always provides a conservative estimate and the dose rates in places where occupational works can always access and the controlled area boundary are expected to be far less than the legal criteria throughout the injector commissioning.

  20. Performance of a MICROMEGAS-based TPC in a high-energy neutron beam

    Science.gov (United States)

    Snyder, L.; Manning, B.; Bowden, N. S.; Bundgaard, J.; Casperson, R. J.; Cebra, D. A.; Classen, T.; Duke, D. L.; Gearhart, J.; Greife, U.; Hagmann, C.; Heffner, M.; Hensle, D.; Higgins, D.; Isenhower, D.; King, J.; Klay, J. L.; Geppert-Kleinrath, V.; Loveland, W.; Magee, J. A.; Mendenhall, M. P.; Sangiorgio, S.; Seilhan, B.; Schmitt, K. T.; Tovesson, F.; Towell, R. S.; Walsh, N.; Watson, S.; Yao, L.; Younes, W.

    2018-02-01

    The MICROMEGAS (MICRO-MEsh GAseous Structure) charge amplification structure has found wide use in many detection applications, especially as a gain stage for the charge readout of Time Projection Chambers (TPCs). Here we report on the behavior of a MICROMEGAS TPC when operated in a high-energy (up to 800 MeV) neutron beam. It is found that neutron-induced reactions can cause discharges in some drift gas mixtures that are stable in the absence of the neutron beam. The discharges result from recoil ions close to the MICROMEGAS that deposit high specific ionization density and have a limited diffusion time. For a binary drift gas, increasing the percentage of the molecular component (quench gas) relative to the noble component and operating at lower pressures generally improves stability.

  1. Dual-fission chamber and neutron beam characterization for fission product yield measurements using monoenergetic neutrons

    Science.gov (United States)

    Bhatia, C.; Fallin, B.; Gooden, M. E.; Howell, C. R.; Kelley, J. H.; Tornow, W.; Arnold, C. W.; Bond, E. M.; Bredeweg, T. A.; Fowler, M. M.; Moody, W. A.; Rundberg, R. S.; Rusev, G.; Vieira, D. J.; Wilhelmy, J. B.; Becker, J. A.; Macri, R.; Ryan, C.; Sheets, S. A.; Stoyer, M. A.; Tonchev, A. P.

    2014-09-01

    A program has been initiated to measure the energy dependence of selected high-yield fission products used in the analysis of nuclear test data. We present out initial work of neutron activation using a dual-fission chamber with quasi-monoenergetic neutrons and gamma-counting method. Quasi-monoenergetic neutrons of energies from 0.5 to 15 MeV using the TUNL 10 MV FM tandem to provide high-precision and self-consistent measurements of fission product yields (FPY). The final FPY results will be coupled with theoretical analysis to provide a more fundamental understanding of the fission process. To accomplish this goal, we have developed and tested a set of dual-fission ionization chambers to provide an accurate determination of the number of fissions occurring in a thick target located in the middle plane of the chamber assembly. Details of the fission chamber and its performance are presented along with neutron beam production and characterization. Also presented are studies on the background issues associated with room-return and off-energy neutron production. We show that the off-energy neutron contribution can be significant, but correctable, while room-return neutron background levels contribute less than <1% to the fission signal.

  2. Superconducting magnetic Wollaston prism for neutron spin encoding

    Energy Technology Data Exchange (ETDEWEB)

    Li, F., E-mail: fankli@indiana.edu; Parnell, S. R.; Wang, T.; Baxter, D. V. [Center for Exploration of Energy and Matter, Indiana University, Bloomington, Indiana 47408 (United States); Hamilton, W. A. [Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830 (United States); Maranville, B. B. [National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Semerad, R. [Ceraco Ceramic Coating GmbH, Ismaning 85737 (Germany); Cremer, J. T. [Adelphi Technology Inc., Redwood City, California 94063 (United States); Pynn, R. [Center for Exploration of Energy and Matter, Indiana University, Bloomington, Indiana 47408 (United States); Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830 (United States)

    2014-05-15

    A magnetic Wollaston prism can spatially split a polarized neutron beam into two beams with different neutron spin states, in a manner analogous to an optical Wollaston prism. Such a Wollaston prism can be used to encode the trajectory of neutrons into the Larmor phase associated with their spin degree of freedom. This encoding can be used for neutron phase-contrast radiography and in spin echo scattering angle measurement (SESAME). In this paper, we show that magnetic Wollaston prisms with highly uniform magnetic fields and low Larmor phase aberration can be constructed to preserve neutron polarization using high temperature superconducting (HTS) materials. The Meissner effect of HTS films is used to confine magnetic fields produced electromagnetically by current-carrying HTS tape wound on suitably shaped soft iron pole pieces. The device is cooled to ∼30 K by a closed cycle refrigerator, eliminating the need to replenish liquid cryogens and greatly simplifying operation and maintenance. A HTS film ensures that the magnetic field transition within the prism is sharp, well-defined, and planar due to the Meissner effect. The spin transport efficiency across the device was measured to be ∼98.5% independent of neutron wavelength and energizing current. The position-dependent Larmor phase of neutron spins was measured at the NIST Center for Neutron Research facility and found to agree well with detailed simulations. The phase varies linearly with horizontal position, as required, and the neutron beam shows little depolarization. Consequently, the device has advantages over existing devices with similar functionality and provides the capability for a large neutron beam (20 mm × 30 mm) and an increase in length scales accessible to SESAME to beyond 10 μm. With further improvements of the external coupling guide field in the prototype device, a larger neutron beam could be employed.

  3. Superconducting magnetic Wollaston prism for neutron spin encoding

    Science.gov (United States)

    Li, F.; Parnell, S. R.; Hamilton, W. A.; Maranville, B. B.; Wang, T.; Semerad, R.; Baxter, D. V.; Cremer, J. T.; Pynn, R.

    2014-05-01

    A magnetic Wollaston prism can spatially split a polarized neutron beam into two beams with different neutron spin states, in a manner analogous to an optical Wollaston prism. Such a Wollaston prism can be used to encode the trajectory of neutrons into the Larmor phase associated with their spin degree of freedom. This encoding can be used for neutron phase-contrast radiography and in spin echo scattering angle measurement (SESAME). In this paper, we show that magnetic Wollaston prisms with highly uniform magnetic fields and low Larmor phase aberration can be constructed to preserve neutron polarization using high temperature superconducting (HTS) materials. The Meissner effect of HTS films is used to confine magnetic fields produced electromagnetically by current-carrying HTS tape wound on suitably shaped soft iron pole pieces. The device is cooled to ˜30 K by a closed cycle refrigerator, eliminating the need to replenish liquid cryogens and greatly simplifying operation and maintenance. A HTS film ensures that the magnetic field transition within the prism is sharp, well-defined, and planar due to the Meissner effect. The spin transport efficiency across the device was measured to be ˜98.5% independent of neutron wavelength and energizing current. The position-dependent Larmor phase of neutron spins was measured at the NIST Center for Neutron Research facility and found to agree well with detailed simulations. The phase varies linearly with horizontal position, as required, and the neutron beam shows little depolarization. Consequently, the device has advantages over existing devices with similar functionality and provides the capability for a large neutron beam (20 mm × 30 mm) and an increase in length scales accessible to SESAME to beyond 10 μm. With further improvements of the external coupling guide field in the prototype device, a larger neutron beam could be employed.

  4. Observation of spatial splitting of a polarized neutron beam as it is refracted on the interface of two magnetically non-collinear media

    International Nuclear Information System (INIS)

    Aksenov, V.L.; Kozhevnikov, S.V.; Nikitenko, Yu.V.; Fredrikze, H.; Rekveldt, M.Th.; Schreiber, J.

    1998-01-01

    In the conducted experimental investigation of neutron refraction on the interface of two magnetically non-collinear media spatial splitting of a polarized neutron beam was observed. The beam of neutrons initially in the spin state '+' or '-' splits into two beams of neutrons in the states '+' and '-'. All four split beams have different spatial positions. The reported phenomenon has been observed for the first time

  5. On the possible use of the MASURCA reactor as a flexible, high-intensity, fast neutron beam facility

    Science.gov (United States)

    Dioni, Luca; Jacqmin, Robert; Sumini, Marco; Stout, Brian

    2017-09-01

    In recent work [1, 2], we have shown that the MASURCA research reactor could be used to deliver a fairly-intense continuous fast neutron beam to an experimental room located next to the reactor core. As a consequence of the MASURCA favorable characteristics and diverse material inventories, the neutron beam intensity and spectrum can be further tailored to meet the users' needs, which could be of interest for several applications. Monte Carlo simulations have been performed to characterize in detail the extracted neutron (and photon) beam entering the experimental room. These numerical simulations were done for two different bare cores: A uranium metallic core (˜30% 235U enriched) and a plutonium oxide core (˜25% Pu fraction, ˜78% 239Pu). The results show that the distinctive resonance energy structures of the two core leakage spectra are preserved at the channel exit. As the experimental room is large enough to house a dedicated set of neutron spectrometry instruments, we have investigated several candidate neutron spectrum measurement techniques, which could be implemented to guarantee well-defined, repeatable beam conditions to users. Our investigation also includes considerations regarding the gamma rays in the beams.

  6. Design of neutron beams at the Argonne Continuous Wave Linac (ACWL) for boron neutron capture therapy and neutron radiography

    International Nuclear Information System (INIS)

    Zhou, X.L.; McMichael, G.E.

    1994-01-01

    Neutron beams are designed for capture therapy based on p-Li and p-Sc reactions using the Argonne Continuous Wave Linac (ACWL). The p-Li beam will provide a 2.5 x 10 9 n/cm 2 s epithermal flux with 7 x 10 5 γ/cm 2 s contamination. On a human brain phantom, this beam allows an advantage depth (AD) of 10 cm, an advantage depth dose rate (ADDR) of 78 cGy/min and an advantage ratio (AR) of 3.2. The p-Sc beam offers 5.9 x 10 7 n/cm 2 s and a dose performance of AD = 8 cm and AR = 3.5, suggesting the potential of near-threshold (p,n) reactions such as the p-Li reaction at E p = 1.92 MeV. A thermal radiography beam could also be obtained from ACWL

  7. Neutron production and ion beam generation in plasma focus devices

    International Nuclear Information System (INIS)

    Steinmetz, K.

    1980-01-01

    Concerning the physical processes leading to neutron emission, a clearer situation has been achieved compared to the state at the start of this work. The general discussion will realize that the whole experimental data cannot be described consistently by the predictions of either the beam-target model or the quasi-thermonuclear fusion model, although many questions about the neutron production properties have been solved. In particular the neutron fluence anisotropy is found to be a property basically related to the existence of fast ions escaping axially out of the pinch region. The requirements to explain broad radial neutron energy spectra, long emission times, and energetic but not spatial emission anisotropies suggest a kind of particle trapping in the main source region. (orig./HT)

  8. BEAM-LOSS DRIVEN DESIGN OPTIMIZATION FOR THE SPALLATION NEUTRON SOURCE (SNS) RING.

    Energy Technology Data Exchange (ETDEWEB)

    WEI,J.; BEEBE-WANG,J.; BLASKIEWICZ,M.; CAMERON,P.; DANBY,G.; GARDNER,C.J.; JACKSON,J.; LEE,Y.Y.; LUDEWIG,H.; MALITSKY,N.; RAPARIA,D.; TSOUPAS,N.; WENG,W.T.; ZHANG,S.Y.

    1999-03-29

    This paper summarizes three-stage design optimization for the Spallation Neutron Source (SNS) ring: linear machine design (lattice, aperture, injection, magnet field errors and misalignment), beam core manipulation (painting, space charge, instabilities, RF requirements), and beam halo consideration (collimation, envelope variation, e-p issues etc.).

  9. Beam-Loss Driven Design Optimization for the Spallation Neutron Source (SNS) Ring

    International Nuclear Information System (INIS)

    Wei, J.

    1999-01-01

    This paper summarizes three-state design optimization for the Spallation Neutron Source (SNS) ring: linear machine design (lattice, aperture, injection, magnet field errors and misalignment), beam core manipulation (painting, space charge, instabilities, RF requirements), and beam halo consideration (collimation, envelope variation, e-p issues etc.)

  10. THE METHODS OF PRODUCING AND ANALYZING POLARIZED NEUTRON BEAMS FOR HYSPEC AT THE SNS

    International Nuclear Information System (INIS)

    SHAPIRO, S.M.; PASSELL, L.; ZALIZNYAK, A.; GHOSH, V.J.; LEONHARDT, W.L.; HAGEN, M.E.

    2005-01-01

    The Hybrid Spectrometer (HYSPEC), under construction at the SNS on beam line 14B, is the only inelastic scattering instrument designed to enable polarization of the incident and the scattered neutron beams. A Heusler monochromator will replace the graphite crystal for producing polarized neutrons. In the scattered beam it is planned to use a collimator--multi-channel supermirror bender array to analyze the polarization of the scattered beam over the final energy range from 5-20 meV. Other methods of polarization analysis under consideration such as transmission filters using He 3 , Sm, and polarized protons are considered. Their performance is estimated and a comparison of the various methods of polarization is made

  11. Plasma focus neutron anisotropy measurements and influence of a deuteron beam obstacle

    Energy Technology Data Exchange (ETDEWEB)

    Talebitaher, A. [Physics Department, University of Regina, Saskatchewan, Canada S4S 0A2 (Canada); Springham, S.V., E-mail: stuart.springham@nie.edu.sg [Natural Sciences and Science Education, National Institute of Education, 637616 (Singapore); Rawat, R.S.; Lee, P. [Natural Sciences and Science Education, National Institute of Education, 637616 (Singapore)

    2017-03-11

    The deuterium-deuterium (DD) fusion neutron yield and anisotropy were measured on a shot-to-shot basis for the NX2 plasma focus (PF) device using two beryllium fast-neutron activation detectors at 0° and 90° to the PF axis. Measurements were performed for deuterium gas pressures in the range 6–16 mbar, and positive correlations between neutron yield and anisotropy were observed at all pressures. Subsequently, at one deuterium gas pressure (13 mbar), the contribution to the fusion yield produced by the forwardly-directed D{sup +} ion beam, emitted from the plasma pinch, was investigated by using a circular Pyrex plate to obstruct the beam and suppress its fusion contribution. Neutron measurements were performed with the obstacle positioned at two distances from the anode tip, and also without the obstacle. It was found that ~ 80% of the neutron yield originates in the plasma pinch column and just above that. In addition, proton pinhole imaging was performed from the 0° and 90° directions to the pinch. The obtained proton images are consistent with the conclusion that DD fusion is concentrated (~ 80%) in the pinch column region.

  12. Opportunities for research using neutron beams at Australia's replacement research reactor

    International Nuclear Information System (INIS)

    Robinson, R.A.

    2000-01-01

    Full text: On July 13th 2000, a contract was signed for construction of Australia's Replacement Research Reactor at Lucas Heights just outside Sydney. This may represent Australia's largest single investment in scientific infrastructure, and it provides researchers in condensed matter physics, chemistry, materials science, and some aspects of engineering, the earth sciences and biology with the 'opportunity of a generation' The replacement reactor, which will commence operation in 2005, will be comparable with the national neutron sources of Japan, France and the U.S.A. Cold and thermal neutron sources are to be installed and supermirror guides will transport cold and thermal neutron beams into a large modern guide hall. The reactor and all the associated infrastructure, with the exception of the neutron beam instruments, is to be built by the Argentinian company INVAP S.E., in collaboration with two Australian firms, in a turnkey contract. The instruments will be developed by ANSTO and other contracted organisations, in consultation with the Australian user community and interested overseas parties. This presentation reviews the planned scientific capabilities and opportunities, gives a description of the facility and a status report on the activities so far

  13. External beam radiotherapy in the management of ovarian carcinoma

    International Nuclear Information System (INIS)

    Reinfuss, Marian; Zbigniew, Kojs; Skolyszewski, Jan

    1993-01-01

    Between 1970 and 1983, 345 patients with ovarian cancer clinical stage I, II and III were irradiated postoperatively. Five-year NED survival was achieved in 41.7% of patients. The most important prognostic factors were histological grade and clinical stage of cancer. Postoperative external beam radiotherapy appeared to be highly efficient for the patients with microscopic residual disease, giving 70% 5-year survival, and moderately efficient for patients with small, i.e. ≤3 cm in diameter residual disease, giving 40% 5-year survival. The optimal technique of irradiation appeared to be the irradiation given to the entire abdominal cavity with additional irradiation coned down to the pelvis. External beam radiotherapy was ineffective in patients with gross residual disease, i.e. >3 cm in diameter, and useless as palliative treatment given to patients with inoperable cancer of the ovary. (author). tabs., figs

  14. In-beam test of Neutron detector array facility at IUAC

    International Nuclear Information System (INIS)

    Sugathan, P.; Jhingan, A.; Saneesh, S.

    2014-01-01

    A new experimental facility dedicated for the study of fission dynamics has been installed and commissioned recently at Inter University Accelerator Centre (IUAC), New Delhi. The facility, National Array of Neutron Detectors (NAND) is used for the systematic studies on fission dynamics around Coulomb barrier energies using heavy ion beams from the Tandem plus LINAC accelerator facilities. The detector array consists 100 neutron detectors mounted on a geodesic dome structure at a radial distance of 175 cm from the target and multi wire proportional counters (MWPC) for detection of fission fragments. Each neutron detector is made of 5'' x 5'' cylindrical cell filled with BC501A organic liquid scintillator and coupled to a 5'' photo multiplier tube. A 100 cm diameter spherical vacuum chamber has been installed at the center of the array to house the targets, fission fragment detectors and other ancillary charged particle detectors. The vacuum chamber is made of 4mm thick steel and has target ladder with linear and rotary movements. The detector array is installed on a dedicated beam line of LINAC accelerator facilities at beam hall II. The neutrons are discriminated from gamma rays using pulse shape discrimination (PSD) technique based on conventional analog electronics and the energies of neutrons are measured by the time of flight (TOF) method. For this purpose, custom made electronics modules have been built to process signal from each detector. This module contains the integrated electronics for n - γ discrimination, time of flight (TOF) and light output. The fission fragments are detected in low pressure MWPCs mounted inside the spherical vacuum chamber. The MWPC has been built based on the conventional design using three electrodes, having a central cathode foil electrode sandwiched between two position sensing anode wire/strip frames. In order to acquire data from detector array, the data acquisition system has been implemented using VME based hardware systems

  15. Determination of Thermal Neutron Capture Cross Sections Using Cold Neutron Beams at the Budapest PGAA-NIPS Facilities

    International Nuclear Information System (INIS)

    Belgya, T.

    2006-01-01

    A complete elemental gamma-ray library was measured with our guided thermal beam at the Budapest PGAA facility in the period of 1995-2000. Using this data library in an IAEA CRP on PGAA it was managed to re-normalize the ENSDF intensity data with the Budapest intensities. Based on this renormalization thermal neutron cross sections were deduced for several isotopes. Most of these calculations were done by Richard B. Firestone. The Budapest PGAA-NIPS facilities have been used for routine prompt gamma activation analysis with cold neutrons since the year of 2000. The advantage of the cold neutron beam is that the neutron guide has much higher neutron transmission. This resulted in a gain factor about 20 relative to our thermal guide. For the analytical works a precise comparator technique was developed that is routinely used to determine partial gamma-ray production cross sections. An additional development of our methodology was necessary to be worked out to determine thermal neutron capture cross sections based on the partial gamma-ray production cross sections. In this talk our methodology of radiative capture cross section determination will be presented, including our latest results on 129 I, 204,206,207 Pb and 209 Bi. Most of these works were done in cooperation with people from EU-JRC-IRMM, Geel, Belgium and CEA Cadarache, France. Many partial cross sections of short lived nuclei have been re-measured with our new chopper technique. The uncertainty calculations of the radiative capture cross section determination procedures will be also shown. (authors)

  16. The fast neutron facility at the research reactor Munich. Determination of the beam quality and medical applications

    International Nuclear Information System (INIS)

    Wagner, F. M.; Koester, L.

    1990-01-01

    At the research reactor FRM, fast and epithermal neutron beams are generated by a thermal-to-fast neutron converter and/or near core scatterers. The dosimetry and spectroscopy of the resulting intense mixed beams of neutron and gamma radiation with a wide range of energies set spetial tasks for neutron dosimetry and spectroscopy. The twin chamber method and some others are briefly described. Neutron spectroscopy is performed by a Li-6 sandwich spectrometer covering the full neutron spectrum of a well-collimated mixed beam from about 20 keV to 8 MeV. The data registration is assisted by a microcomputer which generates sum and triton spectra on-line. Sum analysis is applied to neutron energies greater than 0.3 MeV; the intermediate neutron spectrum is evaluated by unfolding of the triton spectrum. Moreover, a brief overview of the reactor neutron therapy (RENT) at the FRM is given. After a number of animal experiments for the determination of the biological effectiveness relative to X-rays, clinical irradiations have been started in 1985. The most important indications for RENT are listed. 140 patients with bad prognoses have been treated since. The average tumour control rate of 60% is surprisingly high. Possibilities for an assisting Boron Neutron Capture Therapy (BNCT) are shown. 8 figs., 23 refs

  17. Fluence-to-absorbed-dose conversion coefficients for neutron beams from 0.001 eV to 100 GeV calculated for a set of pregnant female and fetus models

    International Nuclear Information System (INIS)

    Taranenko, Valery; Xu, X George

    2008-01-01

    Protection of fetuses against external neutron exposure is an important task. This paper reports a set of absorbed dose conversion coefficients for fetal and maternal organs for external neutron beams using the RPI-P pregnant female models and the MCNPX code. The newly developed pregnant female models represent an adult female with a fetus including its brain and skeleton at the end of each trimester. The organ masses were adjusted to match the reference values within 1%. For the 3 mm cubic voxel size, the models consist of 10-15 million voxels for 35 organs. External monoenergetic neutron beams of six standard configurations (AP, PA, LLAT, RLAT, ROT and ISO) and source energies 0.001 eV-100 GeV were considered. The results are compared with previous data that are based on simplified anatomical models. The differences in dose depend on source geometry, energy and gestation periods: from 20% up to 140% for the whole fetus, and up to 100% for the fetal brain. Anatomical differences are primarily responsible for the discrepancies in the organ doses. For the first time, the dependence of mother organ doses upon anatomical changes during pregnancy was studied. A maximum of 220% increase in dose was observed for the placenta in the nine months model compared to three months, whereas dose to the pancreas, small and large intestines decreases by 60% for the AP source for the same models. Tabulated dose conversion coefficients for the fetus and 27 maternal organs are provided

  18. Radioactive beam EXperiments at ISOLDE : Coulomb excitation and neutron transfer reactions of exotic nuclei.

    CERN Multimedia

    Kugler, E; Ratzinger, U; Wenander, F J C

    2002-01-01

    % IS347 \\\\ \\\\We propose to perform a pilot experiment to study very neutron rich (A<32) Na-Mg and (A<52) K-Ca isotopes in the region around the neutron shell closures of N=20 and N=28 after Coulomb excitation and neutron transfer, and to demonstrate highly efficient and cost-effective ways to bunch, charge-state breed and accelerate already existing mass-separated singly-charged radioactive ion beams. \\\\ \\\\To do this we plan to accelerate the ISOLDE beams up to 2~MeV/u by means of a novel acceleration scheme and to install an efficient $\\gamma$-ray array for low-multiplicity events around the target position.

  19. A 14-MeV beam-plasma neutron source for materials testing

    International Nuclear Information System (INIS)

    Futch, A.H.; Coensgen, F.H.; Damm, C.C.; Molvik, A.W.

    1989-01-01

    The design and performance of 14-MeV beam-plasma neutron sources for accelerated testing of fusion reactor materials are described. Continuous production of 14-MeV neutron fluxes in the range of 5 to 10 MW/m 2 at the plasma surface are produced by D-T reactions in a two-component plasma. In the present designs, 14-MeV neutrons result from collisions of energetic deuterium ions created by transverse injection of 150-keV deuterium atoms on a fully ionized tritium target plasma. The beam energy, which deposited at the center of the tritium column, is transferred to the warm plasma by electron drag, which flows axially to the end regions. Neutral gas at high pressure absorbs the energy in the tritium plasma and transfers the heat to the walls of the vacuum vessel. The plasma parameters of the neutron source, in dimensionless units, have been achieved in the 2XIIB high-β plasma. The larger magnetic field of the present design permits scaling to the higher energy and density of the neutron source design. In the extrapolation, care has been taken to preserve the scaling and plasma attributes that contributed to equilibrium, magnetohydrodynamic (MHD) stability, and microstability in 2XIIB. The performance and scaling characteristics are described for several designs chosen to enhance the thermal isolation of the two-component plasmas. 11 refs., 3 figs., 3 tabs

  20. Computer dosimetry for flattened and wedged fast-neutron beams

    International Nuclear Information System (INIS)

    Hogstrom, K.R.; Smith, A.R.; Almond, P.R.; Otte, V.A.; Smathers, J.B.

    1976-01-01

    Beam flattening by the use of polyethylene filters has been developed for the 50-MeV d→Be fast-neutron therapy beam at the Texas AandM Variable-Energy Cyclotron (TAMVEC) as a result of the need for a more uniform dose distribution at depth within the patient. A computer algorithm has been developed that allows the use of a modified decrement line method to calculate dose distributions; standard decrement line methods do not apply because of off-axis peaking. The dose distributions for measured flattened beams are transformed into distributions that are physically equivalent to an unflattened distribution. In the transformed space, standard decrement line theory yields a distribution for any field size which, by applying the inverse transformation, generates the flattened dose distribution, including the off-axis peaking. A semiempirical model has been constructed that allows the calculation of dose distributions for wedged beams from open-beam data

  1. Dose-rate effects in external beam radiotherapy redux

    International Nuclear Information System (INIS)

    Ling, C. Clifton; Gerweck, Leo E.; Zaider, Marco; Yorke, Ellen

    2010-01-01

    Recent developments in external beam radiotherapy, both in technical advances and in clinical approaches, have prompted renewed discussions on the potential influence of dose-rate on radio-response in certain treatment scenarios. We consider the multiple factors that influence the dose-rate effect, e.g. radical recombination, the kinetics of sublethal damage repair for tumors and normal tissues, the difference in α/β ratio for early and late reacting tissues, and perform a comprehensive literature review. Based on radiobiological considerations and the linear-quadratic (LQ) model we estimate the influence of overall treatment time on radio-response for specific clinical situations. As the influence of dose-rate applies to both the tumor and normal tissues, in oligo-fractionated treatment using large doses per fraction, the influence of delivery prolongation is likely important, with late reacting normal tissues being generally more sensitive to the dose-rate effect than tumors and early reacting tissues. In conventional fractionated treatment using 1.8-2 Gy per fraction and treatment times of 2-10 min, the influence of dose-rate is relatively small. Lastly, the dose-rate effect in external beam radiotherapy is governed by the overall beam-on-time, not by the average linac dose-rate, nor by the instantaneous dose-rate within individual linac pulses which could be as high as 3 x 10 6 MU/min.

  2. Long distance propagation of a polarized neutron beam in zero magnetic field

    International Nuclear Information System (INIS)

    Schmidt, U.; Bitter, T.; El-Muzeini, P.

    1992-01-01

    A beam of fully polarized cold neutrons was transported through a zero magnetic field region of 70 m length without loss of polarization. The purpose of this exercise was twofold: Firstly, to demonstrate that the new zero-field neutron spin-echo method will work also for very long neutron flight paths; secondly, to prove in the most direct way that the neutron free-flight region of the ILL neutron-antineutron oscillation experiment was indeed sufficiently field-free ('quasifree condition') by using the neutrons themselves as a magnetometer. To this purpose the residual magnetic field integrals in the long 'zero-field' region were measured with a conventional neutron spin-echo method. The overall spin precession angle of the neutrons during their flight through the long zero-field region was found to be less than 2 0 . (orig.)

  3. Peculiarities of using mixed deuterium and tritium ion beams of complicated atomic-molecular composition for fast neutron generation

    International Nuclear Information System (INIS)

    Kir'yanov, G.I.; Syromukov, S.V.

    1983-01-01

    The neutron yield is calculated depending on deuterium and tritium beam parameters as well as on the target parameters. Cases of target presaturation with hydrogen nuclides and of target stuffing with the ion beam in the process of the system functioning are discussed. It is shown that the neutron yield is approximately three times more in the case with a pure beam compared to the case with a niked beam

  4. The n_TOF facility: Neutron beams for challenging future measurements at CERN

    Science.gov (United States)

    Chiaveri, E.; Aberle, O.; Andrzejewski, J.; Audouin, L.; Bacak, M.; Balibrea, J.; Barbagallo, M.; Bečvář, F.; Berthoumieux, E.; Billowes, J.; Bosnar, D.; Brown, A.; Caamaño, M.; Calviño, F.; Calviani, M.; Cano-Ott, D.; Cardella, R.; Casanovas, A.; Cerutti, F.; Chen, Y. H.; Colonna, N.; Cortés, G.; Cortés-Giraldo, M. A.; Cosentino, L.; Damone, L. A.; Diakaki, M.; Domingo-Pardo, C.; Dressler, R.; Dupont, E.; Durán, I.; Fernández-Domínguez, B.; Ferrari, A.; Ferreira, P.; Finocchiaro, P.; Göbel, K.; García, A. R.; Gawlik, A.; Gilardoni, S.; Glodariu, T.; Gonçalves, I. F.; González, E.; Griesmayer, E.; Guerrero, C.; Gunsing, F.; Harada, H.; Heinitz, S.; Heyse, J.; Jenkins, D. G.; Jericha, E.; Käppeler, F.; Kadi, Y.; Kalamara, A.; Kavrigin, P.; Kimura, A.; Kivel, N.; Kokkoris, M.; Krtička, M.; Kurtulgil, D.; Leal-Cidoncha, E.; Lederer, C.; Leeb, H.; Lerendegui-Marco, J.; Meo, S. Lo; Lonsdale, S. J.; Macina, D.; Marganiec, J.; Martínez, T.; Masi, A.; Massimi, C.; Mastinu, P.; Mastromarco, M.; Maugeri, E. A.; Mazzone, A.; Mendoza, E.; Mengoni, A.; Milazzo, P. M.; Mingrone, F.; Musumarra, A.; Negret, A.; Nolte, R.; Oprea, A.; Patronis, N.; Pavlik, A.; Perkowski, J.; Porras, I.; Praena, J.; Quesada, J. M.; Radeck, D.; Rauscher, T.; Reifarth, R.; Rubbia, C.; Ryan, J. A.; Sabaté-Gilarte, M.; Saxena, A.; Schillebeeckx, P.; Schumann, D.; Smith, A. G.; Sosnin, N. V.; Stamatopoulos, A.; Tagliente, G.; Tain, J. L.; Tarifeño-Saldivia, A.; Tassan-Got, L.; Tsinganis, A.; Valenta, S.; Vannini, G.; Variale, V.; Vaz, P.; Ventura, A.; Vlachoudis, V.; Vlastou, R.; Wallner, A.; Warren, S.; Woods, P. J.; Wright, T.; Žugec, P.

    2017-09-01

    The CERN n_TOF neutron beam facility is characterized by a very high instantaneous neutron flux, excellent TOF resolution at the 185 m long flight path (EAR-1), low intrinsic background and coverage of a wide range of neutron energies, from thermal to a few GeV. These characteristics provide a unique possibility to perform high-accuracy measurements of neutron-induced reaction cross-sections and angular distributions of interest for fundamental and applied Nuclear Physics. Since 2001, the n_TOF Collaboration has collected a wealth of high quality nuclear data relevant for nuclear astrophysics, nuclear reactor technology, nuclear medicine, etc. The overall efficiency of the experimental program and the range of possible measurements has been expanded with the construction of a second experimental area (EAR-2), located 20 m on the vertical of the n_TOF spallation target. This upgrade, which benefits from a neutron flux 30 times higher than in EAR-1, provides a substantial extension in measurement capabilities, opening the possibility to collect data on neutron cross-section of isotopes with short half-lives or available in very small amounts. This contribution will outline the main characteristics of the n_TOF facility, with special emphasis on the new experimental area. In particular, we will discuss the innovative features of the EAR-2 neutron beam that make possible to perform very challenging measurements on short-lived radioisotopes or sub-mg samples, out of reach up to now at other neutron facilities around the world. Finally, the future perspectives of the facility will be presented.

  5. Neutron therapy in the 21. century

    International Nuclear Information System (INIS)

    Kroc, Thomas K.; Welsh, James S.

    2015-01-01

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

  6. Bilateral Rhegmatogenous Retinal Detachment during External Beam Radiotherapy

    Directory of Open Access Journals (Sweden)

    Takako Hidaka

    2016-06-01

    Full Text Available Herein, we report a case of nontraumatic bilateral rhegmatogenous retinal detachment (RRD during external beam radiotherapy for nonocular tumor, presented as an observational case study in conjunction with a review of the relevant literature. A 65-year-old male was referred to our hospital due to bilateral RRD. He underwent a biopsy for a tumor of the left frontal lobe 4 months prior to presentation, and the tumor had been diagnosed as primary central nerve system B-cell type lymphoma. He received chemotherapy and external beam radiotherapy for 1 month. There were no traumatic episodes. Bilateral retinal detachment occurred during a series of radiotherapies. Simultaneous nontraumatic bilateral retinal detachment is rare. The effects of radiotherapy on ocular functionality, particularly in cases involving retinal adhesion and vitreous contraction, may include RRD. Thus, it is necessary to closely monitor the eyes of patients undergoing radiotherapy, particularly those undergoing surgery for retinal detachment and those with a history of photocoagulation for retinal tears, a relevant family history, or risk factors known to be associated with RRD.

  7. Feasibility of the utilization of BNCT in the fast neutron therapy beam at Fermilab

    International Nuclear Information System (INIS)

    Langen, Katja; Lennox, Arlene J.; Kroc, Thomas K.; DeLuca, Paul M. Jr.

    2000-01-01

    The Neutron Therapy Facility at Fermilab has treated cancer patients since 1976. Since then more than 2,300 patients have been treated and a wealth of clinical information accumulated. The therapeutic neutron beam at Fermilab is produced by bombarding a beryllium target with 66 MeV protons. The resulting continuous neutron spectrum ranges from thermal to 66 MeV in neutron energy. It is clear that this spectrum is not well suited for the treatment of tumors with boron neutron capture therapy (BNCT) only However, since this spectrum contains thermal and epithermal components the authors are investigating whether BNCT can be used in this beam to boost the tumor dose. There are clinical scenarios in which a selective tumor dose boost of 10 - 15% could be clinically significant. For these cases the principal treatment would still be fast neutron therapy but a tumor boost could be used either to deliver a higher dose to the tumor tissue or to reduce the dose to the normal healthy tissue while maintaining the absorbed dose level in the tumor tissue

  8. The University of Texas Cold Neutron Source

    International Nuclear Information System (INIS)

    Uenlue, Kenan; Rios-Martinez, Carlos; Wehring, B.W.

    1994-01-01

    A cold neutron source has been designed, constructed, and tested by the Nuclear Engineering Teaching Laboratory (NETL) at The University of Texas at Austin. The Texas Cold Neutron Source (TCNS) is located in one of the beam ports of the NETL 1-MW TRIGA Mark II research reactor. The main components of the TCNS are a cooled moderator, a heat pipe, a cryogenic refrigerator, and a neutron guide. 80 ml of mesitylene moderator are maintained at about 30 K in a chamber within the reactor graphite reflector by the heat pipe and cryogenic refrigerator. The heat pipe is a 3-m long aluminum tube that contains neon as the working fluid. The cold neutrons obtained from the moderator are transported by a curved 6-m long neutron guide. This neutron guide has a radius of curvature of 300 m, a 50x15 mm cross-section, 58 Ni coating, and is separated into three channels. The TCNS will provide a low-background subthermal neutron beam for neutron capture and scattering research. After the installation of the external portion of the neutron guide, a neutron focusing system and a Prompt Gamma Activation Analysis facility will be set up at the TCNS. ((orig.))

  9. Neutron beam test of multi-grid-type microstrip gas chamber

    International Nuclear Information System (INIS)

    Fujita, K.; Takahashi, H.; Siritiprussamee, P.; Niko, H.; Kai, M.; Nakazawa, M.; Ino, T.; Sato, S.; Yokoo, T.; Furusaka, M.; Kanazawa, M.

    2006-01-01

    Multi-grid-type microstrip gas chambers (M-MSGCs) are being developed for the next-generation pulsed neutron source. Two new concepts, a global-local-grouping (GLG) method and a graded cathode pattern readout method, were applied to the M-MSGC design for realizing higher counting rate than traditional 3 He proportional counters. One-dimensional detectors with 700 mm-long test plates were fabricated and tested with X-ray and neutron beams, which demonstrated position detection capability based on these concepts

  10. Monitoring elastic strain and damage by neutron and synchrotron beams

    International Nuclear Information System (INIS)

    Withers, P.J.

    2001-01-01

    Large-scale neutron and synchrotron X-ray facilities have been providing important information for physicists and chemists for many decades. Increasingly, materials engineers are finding that they can also provide them with important information non-destructively. Highly penetrating neutron and X-ray synchrotron beams provide the materials engineer with a means of obtaining information about the state of stress and damage deep within materials. In this paper the principles underlying the elastic strain measurement and damage characterization techniques are introduced. (orig.)

  11. Health physics considerations at a neutron therapy facility cyclotron

    International Nuclear Information System (INIS)

    Kleck, J.H.; Krueger, D.J.; Mc Laughlin, J.E.; Smathers, J.B.

    1987-01-01

    The U.C.L.A. Neutron Therapy Facility (NTF) is one of four such facilities in the United States currently involved in NCI sponsored trials of neutron therapy and reflects the present interest in the use of high energy neutron beams for treating certain types of human cancers. The NTF houses a CP-45 negative ion cyclotron which accelerates a 46 MeV proton beam for production of neutrons from a beryllium target. In addition to patient treatment, the NTF is involved in the production of positron emitting radioisotopes for diagnostic use in Positron Emission Tomography (PET). The activation of therapy treatment collimators, positron and neutron target systems, and a high and rapidly varying external radiation environment in a clinical setting have contributed to the need for a comprehensive radiation control program in which patient care is balanced with the maintenance of occupational exposures to ALARA levels

  12. np Elastic-scattering experiments with polarized neutron beams

    International Nuclear Information System (INIS)

    Chalmers, J.S.; Ditzler, W.R.; Hill, D.

    1985-01-01

    Measurements of the spin transfer parameters, K/sub NN/ and K/sub LL/, at 500, 650, and 800 MeV are presented for the reaction p-vector d → n-vector pp at 0 0 . The data are useful input to the NN data base and indicate that the quasi-free charge exchange (CEX) reaction is a useful mechanism for producing neutrons with at least 40% polarization at energies as low as 500 MeV. Measurements of np elastic scattering observables C/sub LL/ and C/sub SL/ covering 35 0 to 172 0 are performed using a polarized neutron beam at 500, 650, and 800 MeV. Preliminary results are presented. 3 refs., 6 figs

  13. Neutron scattering-instrumentation at the upgraded research reactor BER II

    International Nuclear Information System (INIS)

    1991-01-01

    The Berlin Neutron Scattering Centre (BENSC) is a newly created special department of the Hahn-Meitner-Institut, in the framework of which the BER II neutron beam reactor is made available to external users. BENSC is devoted to development, continuous modernisation and maintenance of the scientific instrumets at the BER II and to the support of their users. (orig./HSI)

  14. Silicon Photo-Multiplier Radiation Hardness Tests with a White Neutron Beam

    International Nuclear Information System (INIS)

    Montanari, A.; Tosi, N.; Pietropaolo, A.; Andreotti, M.; Baldini, W.; Calabrese, R.; Cibinetto, G.; Luppi, E.; Cotta Ramusino, A.; Malaguti, R.; Santoro, V.; Tellarini, G.; Tomassetti, L.; De Donato, C.; Reali, E.

    2013-06-01

    We report radiation hardness tests performed, with a white neutron beam, at the Geel Electron Linear Accelerator in Belgium on silicon Photo-Multipliers. These are semiconductor photon detectors made of a square matrix of Geiger-Mode Avalanche photo-diodes on a silicon substrate. Several samples from different manufacturers have been irradiated integrating up to about 6.2 x 10 9 1-MeV-equivalent neutrons per cm 2 . (authors)

  15. Optimization of beam shaping assembly based on D-T neutron generator and dose evaluation for BNCT

    Science.gov (United States)

    Naeem, Hamza; Chen, Chaobin; Zheng, Huaqing; Song, Jing

    2017-04-01

    The feasibility of developing an epithermal neutron beam for a boron neutron capture therapy (BNCT) facility based on a high intensity D-T fusion neutron generator (HINEG) and using the Monte Carlo code SuperMC (Super Monte Carlo simulation program for nuclear and radiation process) is proposed in this study. The Monte Carlo code SuperMC is used to determine and optimize the final configuration of the beam shaping assembly (BSA). The optimal BSA design in a cylindrical geometry which consists of a natural uranium sphere (14 cm) as a neutron multiplier, AlF3 and TiF3 as moderators (20 cm each), Cd (1 mm) as a thermal neutron filter, Bi (5 cm) as a gamma shield, and Pb as a reflector and collimator to guide neutrons towards the exit window. The epithermal neutron beam flux of the proposed model is 5.73 × 109 n/cm2s, and other dosimetric parameters for the BNCT reported by IAEA-TECDOC-1223 have been verified. The phantom dose analysis shows that the designed BSA is accurate, efficient and suitable for BNCT applications. Thus, the Monte Carlo code SuperMC is concluded to be capable of simulating the BSA and the dose calculation for BNCT, and high epithermal flux can be achieved using proposed BSA.

  16. The continued development of the Spallation Neutron Source external antenna H- ion source

    International Nuclear Information System (INIS)

    Welton, R. F.; Carmichael, J.; Fuga, R.; Goulding, R. H.; Han, B.; Kang, Y.; Lee, S. W.; Murray, S. N.; Pennisi, T.; Potter, K. G.; Santana, M.; Stockli, M. P.; Desai, N. J.

    2010-01-01

    The U.S. Spallation Neutron Source (SNS) is an accelerator-based, pulsed neutron-scattering facility, currently in the process of ramping up neutron production. In order to ensure that the SNS will meet its operational commitments as well as provide for future facility upgrades with high reliability, we are developing a rf-driven, H - ion source based on a water-cooled, ceramic aluminum nitride (AlN) plasma chamber. To date, early versions of this source have delivered up to 42 mA to the SNS front end and unanalyzed beam currents up to ∼100 mA (60 Hz, 1 ms) to the ion source test stand. This source was operated on the SNS accelerator from February to April 2009 and produced ∼35 mA (beam current required by the ramp up plan) with availability of ∼97%. During this run several ion source failures identified reliability issues, which must be addressed before the source re-enters production: plasma ignition, antenna lifetime, magnet cooling, and cooling jacket integrity. This report discusses these issues, details proposed engineering solutions, and notes progress to date.

  17. PEMODELAN KOLIMATOR DI RADIAL BEAM PORT REAKTOR KARTINI UNTUK BORON NEUTRON CAPTURE THERAPY

    Directory of Open Access Journals (Sweden)

    Bemby Yulio Vallenry

    2015-03-01

    Full Text Available Salah satu metode terapi kanker adalah Boron Neutron Capture Therapy (BNCT. BNCT memanfaatkan tangkapan neutron oleh 10B yang terendapkan pada sel kanker. Keunggulan BNCT dibandingkan dengan terapi radiasi lainnya adalah tingkat selektivitas yang tinggi karena tingkatannya adalah sel. Pada penelitian ini dilakukan pemodelan kolimator di radial beamport reaktor Kartini sebagai dasar pemilihan material dan manufature kolimator sebagai sumber neutron untuk BNCT. Pemodelan ini dilakukan dengan simulasi menggunakan perangkat lunak Monte Carlo N-Particle versi 5 (MCNP 5. MCNP 5 adalah suatu paket program untuk memodelkan sekaligus menghitung masalah transpor partikel dengan mengikuti sejarah hidup neutron semenjak lahir, bertranspor pada bahan hingga akhirnya hilang karena mengalami reaksi penyerapan atau keluar dari sistem. Pemodelan ini menggunakan variasi material dan ukurannya agar menghasilkan nilai dari tiap parameter-parameter yang sesuai dengan rekomendasi I International Atomic Energy Agency (IAEA untuk BNCT, yaitu fluks neutron epitermal (Фepi > 9 n.cm-2.s-1, rasio antara laju dosis neutron cepat dan fluks neutron epitermal (Ḋf/Фepi 0,7. Berdasarkan hasil optimasi dari pemodelan ini, material dan ukuran penyusun kolimator yang didapatkan yaitu 0,75 cm Ni sebagai dinding kolimator, 22 cm Al sebagai moderator dan 4,5 cm Bi sebagai perisai gamma. Keluaran berkas radiasi yang dihasilkan dari pemodelan kolimator radial beamport yaitu Фepi = 5,25 x 106 n.cm-2s-1, Ḋf/Фepi =1,17 x 10-13 Gy.cm2.n-1, Ḋγ/Фepi = 1,70 x 10-12 Gy.cm2.n-1, Фth/Фepi = 1,51 dan J/Фepi = 0,731. Berdasarkan penelitian ini, hasil optimasi 5 parameter sebagai persyaratan kolimator untuk BNCT yang keluar dari radial beam port tidak sepenuhnya memenuhi kriteria yang direkomendasikan oleh IAEA sehingga perlu dilakukan penelitian lebih lanjut agar tercapainya persyaratan IAEA. Kata kunci: BNCT, radial beamport, MCNP 5, kolimator   One of the cancer therapy methods is

  18. Study of an integrated electronic monitor for neutron beams

    International Nuclear Information System (INIS)

    Barelaud, B.; Nexon-Mokhtari, F.; Barrau, C.; Decossac, J.L.; Vareille, J.C.; Sarrabayrouse, G.

    1994-01-01

    Many neutron beams monitors in 10 keV - 50 keV range are perturbed by gamma radiation impact. This new monitor uses two silicon (junction) diodes operating coincidence detection, combined with an electronic threshold to eliminate gamma background noise. The results and analyses presented here only concern feasibility studies. (D.L.)

  19. External beam radiation for retinoblastoma: Results, patterns of failure, and a proposal for treatment guidelines

    International Nuclear Information System (INIS)

    Hernandez, J. Carlos; Brady, Luther W.; Shields, Jerry A.; Shields, Carol L.; Potter, Patrick de; Karlsson, Ulf L.; Markoe, Arnold M.; Amendola, Beatriz E.; Singh, Arun

    1996-01-01

    Purpose: To analyze treatment results and patterns of failure following external beam radiation for retinoblastoma and propose treatment guidelines according to specific clinical variables. Methods and Materials: We analyzed 27 patients (34 eyes) with retinoblastoma who received external beam radiation as initial treatment at Hahnemann University Hospital from October 1980 to December 1991 and have been followed for at least 1 year. Of the 34 eyes, 14 were Groups I-II (Reese-Ellsworth classification), 7 were Group III, and 13 were Groups IV-V. Doses ranged from 34.5-49.5 Gy (mean 44.3 Gy, median 45 Gy) in 1.5-2.0 Gy fractions generally delivered through anterior and lateral wedged pair fields. Results: At a mean follow up of 35.2 months (range 12-93 months), local tumor control was obtained in 44% (15 out of 34) of eyes with external beam radiation alone. Salvage therapy (plaque brachytherapy, cryotherapy, and/or photocoagulation) controlled an additional 10 eyes (29.5%), so that overall ocular survival has been 73.5%. Local tumor control with external beam radiotherapy alone was obtained in 78.5% (11 out of 14) of eyes in Groups I-II, but in only 20% (4 out of 20) of eyes in Groups III-V. A total of 67 existing tumors were identified prior to treatment in the 34 treated eyes and local control with external beam radiation alone was obtained in 87% (46 out of 53) of tumors measuring 15 mm or less and in 50% (7 out of 14) of tumors measuring more than 15 mm. When analyzing patterns of failure in the 19 eyes that relapsed, a total of 28 failure sites were identified and consisted of progression of vitreous seeds in seven instances (25% of failure sites) recurrences from previously existing tumors in 10 instances (36% of failure sites) and development of new tumors in previously uninvolved retina in 11 instances (39% of failure sites). Conclusions: 1) We find that external beam radiation to a dose of 45 Gy in fractions of 1.5 to 2.0 Gy provides adequate tumor control

  20. Structural integrity assessment based on the HFR Petten neutron beam facilities

    CERN Document Server

    Ohms, C; Idsert, P V D

    2002-01-01

    Neutrons are becoming recognized as a valuable tool for structural-integrity assessment of industrial components and advanced materials development. Microstructure, texture and residual stress analyses are commonly performed by neutron diffraction and a joint CEN/ISO Pre-Standard for residual stress analysis is under development. Furthermore neutrons provide for defects analyses, i.e. precipitations, voids, pores and cracks, through small-angle neutron scattering (SANS) or radiography. At the High Flux Reactor, 12 beam tubes have been installed for the extraction of thermal neutrons for such applications. Two of them are equipped with neutron diffractometers for residual stress and structure determination and have been extensively used in the past. Several other facilities are currently being reactivated and upgraded. These include the SANS and radiography facilities as well as a powder diffractometer. This paper summarizes the main characteristics and current status of these facilities as well as recently in...

  1. 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...

  2. A novel design of beam shaping assembly to use D-T neutron generator for BNCT.

    Science.gov (United States)

    Kasesaz, Yaser; Karimi, Marjan

    2016-12-01

    In order to use 14.1MeV neutrons produced by d-T neutron generators, two special and novel Beam Shaping Assemblies (BSA), including multi-layer and hexagonal lattice have been suggested and the effect of them has been investigated by MCNP4C Monte Carlo code. The results show that the proposed BSA can provide the qualified epithermal neutron beam for BNCT. The final epithermal neutron flux is about 6e9 n/cm2.s. The final proposed BSA has some different advantages: 1) it consists of usual and well-known materials (Pb, Al, Fluental and Cd); 2) it has a simple geometry; 3) it does not need any additional gamma filter; 4) it can provide high flux of epithermal neutrons. As this type of neutron source is under development in the world, it seems that they can be used clinically in a hospital considering the proposed BSA. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

    Energy Technology Data Exchange (ETDEWEB)

    Nakajima, Y.; Lin, C. J.; Ochoa-Ricoux, J. P. [Lawrence Berkeley National Laboratory, Berkeley, California (United States); Draeger, E.; White, C. G. [Illinois Institute of Technology, Chicago, Illinois (United States); Luk, K. B.; Steiner, H. [Lawrence Berkeley National Laboratory, Berkeley, California (United States); Department of Physics, University of California, Berkeley, California (United States)

    2015-08-17

    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.

  4. Beam plug replacement and alignment under high radiation conditions for cold neutron facilities at Hanaro

    International Nuclear Information System (INIS)

    Yeong-Garp, Cho; Jin-Won, Shin; Jung-Hee, Lee; Jeong-Soo, Ryu

    2010-01-01

    Full text : The HANARO, an open-tank-in-pool type research reactor of a 30 MWth power in Korea, has been operating for 15 years since its initial criticality in February 1995. The beam port assigned for the cold neutron at HANARO had been used for an 8-m SANS without neutron guides until it was replaced by a cold neutron guide system in 2008. It was developed a cold neutron guide system for the delivery of cold neutrons from the cold neutron source in the reactor to the neutron scattering instruments in the guide hall. Since the HANARO has been operated from 1995, it was a big challenge to replace the existing plug and shutter with the new facilities under high radiation conditions. When the old plug was removed from the beam port in 2008, the radiation level was 230 mSv/hr at the end of beam port. In addition to that, there were more difficult situations such as the poor as-built dimensions of the beam port, limited work space and time constraint due to other constructions in parallel in the reactor hall. Before the removal of the old plug the level of the radiation was measured coming out through a small hole of the plug to estimate the radiation level during the removal of the old plug and installation of a new plug. Based on the measurement and analysis results, special tools and various shielding facilities were developed for the removal of old in-pile plug and the installation of the new in-pile plug assembly safely. In 2008, the old plug and shutter were successfully replaced by the new plug and shutter as shown in this article with a minimum exposure to the workers. A laser tracker system was also one of the main factors in our successful installation and alignment under high radiation conditions and limited work space. The laser tracker was used to measure and align all the mechanical facilities and the neutron guides with a minimum radiation exposure to workers. The alignment of all the guides and accessories were possible during reactor operation because

  5. Corrections in the gold foil activation method for determination of neutron beam density

    DEFF Research Database (Denmark)

    Als-Nielsen, Jens Aage

    1967-01-01

    A finite foil thickness and deviation in the cross section from the 1ν law imply corrections in the determination of neutron beam densities by means of foil activation. These corrections, which depend on the neutron velocity distribution, have been examined in general and are given in a specific...

  6. Voluminous D2 source for intense cold neutron beam production at the ESS

    DEFF Research Database (Denmark)

    Klinkby, Esben Bryndt; Batkov, K.; Mezei, F.

    2014-01-01

    the target for the complementary needs of certain fundamental physics experiments. To facilitate experiments depending on the total number of neutrons in a sizable beam, the option of a voluminous D2 moderator, in a large cross-section extraction guide is discussed and its neutronic performance is assessed....

  7. Ion beam characteristics of the controlatron/zetatron family of the gas filled neutron tubes

    Energy Technology Data Exchange (ETDEWEB)

    Berg, R.S.; Shope, L.A.; O' Neal, M.L.; Boers, J.E.; Bickes, R.W. Jr.

    1981-03-01

    A gas filled tube used to produce a neutron flux with the D(T,He/sup 4/)n reaction is described. Deuterium and tritium ions generated in a reflex discharge are extracted and accelerated to 100 keV by means of an accelerator electrode onto a deutero-tritide target electrode. The electrodes are designed to focus the ion beam onto the target. Total tube currents consisting of extracted ions, unsuppressed secondary electrons, and ions generated by interactions with the background gas are typically 100 mA. The characteristics of the extracted ion beam are discussed. Accelerating voltages greater than 50 kV are required to focus the beam through the accelerator aperture for configurations that give beams with the proper energy density onto the target. The perveance of the beam is discussed. Maximum perveance values are 2 to 20 nanopervs. Tube focusing and neutron production characteristics are described.

  8. Proceedings of neutron irradiation technical meeting on BNCT

    International Nuclear Information System (INIS)

    2000-10-01

    The 'Neutron Irradiation Technical Meeting for Boron Neutron Capture Therapy (BNCT)' was held on March 13, 2000 at Tokai Research Establishment. The Meeting is aimed to introduce the neutron beam facility for medical irradiation at JRR-4 to Japanese researchers widely, as well as providing an opportunity for young researchers, engineers, medical representatives such surgeons and doctors of pharmacology to present their research activities and to exchange valuable information. JAERI researcher presented the performance and the irradiation technology in the JRR-4 neutron beam facility, while external researchers made various and beneficial presentations containing such accelerator-based BNCT, spectrum-shifter, biological effect, pharmacological development and so on. In this meeting, a special lecture titled 'The Dawn of BNCT and Its Development.' was given by MD, Prof. Takashi Minobe, an executive director of Japan Foundation for Emergency Medicine. The 11 of the presented papers are indexed individually. (J.P.N.)

  9. Study of the production of neutron-rich isotope beams issuing from fissions induced by fast neutrons; Etude de la production de faisceaux riches en neutrons par fission induite par neutrons rapides

    Energy Technology Data Exchange (ETDEWEB)

    Lau, Ch

    2000-09-15

    This work is a contribution to the PARRNe project (production of radioactive neutron-rich isotopes). This project is based on the fission fragments coming from the fission of 238-uranium induced by fast neutrons. The fast neutron flux is produced by the collisions of deutons in a converter. Thick targets of uranium carbide and liquid uranium targets have been designed in order to allow a quick release of fission fragments. A device, able to trap on a cryogenic thimble rare gas released by the target, has allowed the production of radioactive nuclei whose half-life is about 1 second. This installation has been settled to different deuton accelerators in the framework of the European collaboration SPIRAL-2. A calibration experiment has proved the feasibility of fixing an ISOL-type isotope separator to a 15 MV tandem accelerator, this installation can provide 500 nA deutons beams whose energy is 26 MeV and be a valuable tool for studying fast-neutron induced fission. Zinc, krypton, rubidium, cadmium, iodine, xenon and cesium beams have been produced in this installation. The most intense beams reach 10000 nuclei by micro-coulomb for 26 MeV deutons. An extra gain of 2 magnitude orders can be obtained by using a more specific ion source and by increasing the thickness of the target. Another extra gain of 2 magnitude orders involves 100 MeV deutons.

  10. Study of an integrated electronic monitor for neutron beams

    Energy Technology Data Exchange (ETDEWEB)

    Barelaud, B.; Nexon-Mokhtari, F.; Barrau, C.; Decossac, J.L.; Vareille, J.C. [Limoges Univ., 87 (France); Sarrabayrouse, G. [Centre National de la Recherche Scientifique (CNRS), 31 - Toulouse (France). Lab. d`Automatique et d`Analyse des Systemes

    1994-12-31

    Many neutron beams monitors in 10 keV - 50 keV range are perturbed by gamma radiation impact. This new monitor uses two silicon (junction) diodes operating coincidence detection, combined with an electronic threshold to eliminate gamma background noise. The results and analyses presented here only concern feasibility studies. (D.L.). 11 refs.

  11. Geometric phase in a split-beam experiment measured with coupled neutron interference loops

    International Nuclear Information System (INIS)

    Hasegawa, Yuji; Zawisky, M.; Rauch, H.; Ioffe, A.

    1996-01-01

    A geometric phase factor is derived for a split-beam experiment as an example of cyclic evolutions. The geometric phase is given by one half of the solid angle independent of the spin of the beam. We observe this geometric phase with a two-loop neutron interferometer, where a reference beam can be added to the beam from one interference loop. All the experimental results show complete agreement with our theoretical treatment. (author)

  12. Experimental and Simulated Characterization of a Beam Shaping Assembly for Accelerator- Based Boron Neutron Capture Therapy (AB-BNCT)

    International Nuclear Information System (INIS)

    Burlon, Alejandro A.; Valda, Alejandro A.; Girola, Santiago; Minsky, Daniel M.; Kreiner, Andres J.

    2010-01-01

    In the frame of the construction of a Tandem Electrostatic Quadrupole Accelerator facility devoted to the Accelerator-Based Boron Neutron Capture Therapy, a Beam Shaping Assembly has been characterized by means of Monte-Carlo simulations and measurements. The neutrons were generated via the 7 Li(p, n) 7 Be reaction by irradiating a thick LiF target with a 2.3 MeV proton beam delivered by the TANDAR accelerator at CNEA. The emerging neutron flux was measured by means of activation foils while the beam quality and directionality was evaluated by means of Monte Carlo simulations. The parameters show compliance with those suggested by IAEA. Finally, an improvement adding a beam collimator has been evaluated.

  13. Determination and analysis of neutron flux distribution on radial Piercing beam port for utilization of Kartini research reactor

    International Nuclear Information System (INIS)

    Widarto

    2002-01-01

    Determination and analysis of neutron flux measurements on radial piercing beam port have been done as completion experimental data document and progressing on utilization of the Kartini research reactor purposes. The analysis and determination of the neutron flux have been carried out by using Au foils detector neutron activation analysis method which put on the radius of cross section (19 cm) and a long of radial piercing beam port (310 cm) Based on the calculation, distribution of the thermal neutron flux is around (8.3 ± 0.9) x 10 5 ncm -2 s -1 to (6.8 ± 0.5) x 10 7 ncm -2 s -1 and fast neutron is (5.0 ± 0.2) x 10 5 ncm -2 s -1 to (1.43 ± 0.6) x 10 7 ncm -2 s -1 . Analyzing by means of curve fitting method could be concluded that the neutron flux distribution on radial piercing beam port has profiled as a polynomial curve. (author)

  14. External Beam Radiotherapy in Metastatic Bone Pain from Solid ...

    African Journals Online (AJOL)

    Key Words: Bone, metastasis, radiotherapy, pain, control randomized ... described the efficacy of external beam radiotherapy in pain .... life of patients with multiple myeloma. Eur. J. ... Rades D, Jeremic B, Hoskin PJ: The Role of ... randomised multicenter trial on single fraction ... "The subjective experience of acute pain. An.

  15. Neutron elastic scattering at very small angles

    CERN Multimedia

    2002-01-01

    This experiment will measure neutron-proton elastic scattering at very small angles and hence very small four-momentum transfer, |t|. The range of |t| depends on the incident neutron momentum of the events but the geometrical acceptance will cover the angular range 0.025 < $\\Theta_{lab}$ < 1.9 mrad. The higher figure could be extended to 8.4 mrad by changing the geometry of the experiment in a later phase. \\\\ \\\\ The neutron beam will be highly collimated and will be derived from a 400 GeV external proton beam of up to $4 \\times 10^{10}$ protons per pulse in the SPS North Area Hall 1. The hydrogen target will be gaseous, operating at 40 atm. pressure and acts as a multiwire proportional chamber to detect the recoil protons. The forward neutron will be detected and located by interaction in a neutron vertex detector and its energy measured by a conventional steel plate calorimeter. \\\\ \\\\ The experiment will cover the angular region of nucleon-nucleon scattering which is dominated by Coulomb scattering ...

  16. The relationship between external beam radiotherapy dose and chronic urinary dysfunction - A methodological critique

    International Nuclear Information System (INIS)

    Rosewall, Tara; Catton, Charles; Currie, Geoffrey; Bayley, Andrew; Chung, Peter; Wheat, Janelle; Milosevic, Michael

    2010-01-01

    Purpose: To perform a methodological critique of the literature evaluating the relationship between external beam radiotherapy dose/volume parameters and chronic urinary dysfunction to determine why consistent associations between dose and dysfunction have not been found. Methods and materials: The radiotherapy literature was reviewed using various electronic medical search engines with appropriate keywords and MeSH headings. Inclusion criteria comprised of; English language articles, published between 1999 and June 2009, incorporating megavoltage external beam photons in standard-sized daily fraction. A methodological critique was then performed, evaluating the factors affected in the quantification of radiotherapy dose and chronic urinary dysfunction. Results: Nine of 22 eligible studies successfully identified a clinically and statistically significant relationship between dose and dysfunction. Accurate estimations of external beam radiotherapy dose were compromised by the frequent use of dosimetric variables which are poor surrogates for the dose received by the lower urinary tract tissue and do not incorporate the effect of daily variations in isocentre and bladder position. The precise categorization of chronic urinary dysfunction was obscured by reliance on subjective and aggregated toxicity metrics which vary over time. Conclusions: A high-level evidence-base for the relationship between external beam radiotherapy dose and chronic urinary dysfunction does not currently exist. The quantification of the actual external beam dose delivered to the functionally important tissues using dose accumulation strategies and the use of objective measures of individual manifestations of urinary dysfunction will assist in the identification of robust relationships between dose and urinary dysfunction for application in widespread clinical practice.

  17. A scatter model for fast neutron beams using convolution of diffusion kernels

    International Nuclear Information System (INIS)

    Moyers, M.F.; Horton, J.L.; Boyer, A.L.

    1988-01-01

    A new model is proposed to calculate dose distributions in materials irradiated with fast neutron beams. Scattered neutrons are transported away from the point of production within the irradiated material in the forward, lateral and backward directions, while recoil protons are transported in the forward and lateral directions. The calculation of dose distributions, such as for radiotherapy planning, is accomplished by convolving a primary attenuation distribution with a diffusion kernel. The primary attenuation distribution may be quickly calculated for any given set of beam and material conditions as it describes only the magnitude and distribution of first interaction sites. The calculation of energy diffusion kernels is very time consuming but must be calculated only once for a given energy. Energy diffusion distributions shown in this paper have been calculated using a Monte Carlo type of program. To decrease beam calculation time, convolutions are performed using a Fast Fourier Transform technique. (author)

  18. External beam pixe programs at the University of California, Davis

    International Nuclear Information System (INIS)

    Eldred, R.A.

    1983-01-01

    A PIXE system in which large or delicate samples are excited by a low-current external proton beam is described. This system has been used to analyze historical printed books and manuscripts, as well as a large variety of archeological artifacts. The steps used to protect the sample from unnecessary beam current are examined. A recent thorough study of the first volume of the Gutenberg 42-line Bible is described in some detail

  19. Intraoperative boron neutron capture therapy for malignant gliomas. First clinical results of Tsukuba phase I/II trial using JAERI mixed thermal-epithermal beam

    International Nuclear Information System (INIS)

    Matsumura, A.; Yamamoto, T.; Shibata, Y.

    2000-01-01

    Since October 1999, a clinical trial of intraoperative boron neutron capture therapy (IOBNCT) is in progress at JRR-4 (Japan Research Reactor-4) in Japan Atomic Energy Research Institute (JAERI) using mixed thermal-epithermal beam (thermal neutron beam I: TNB-I). Compared to pure thermal beam (thermal neutron beam II: TNB-II), TNB-I has an improved neutron delivery into the deep region than TNB-II. The clinical protocol and the preliminary results will be discussed. (author)

  20. Report on neutron beam utilization and study of high Tc superconductors at NRI

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Vuong Huu [Nuclear Physics Dept., Nuclear Research Inst. (NRI), Dalat (Viet Nam)

    1998-10-01

    Utilization of reactor neutron beams at NRI for research and applications up to November 1996 had been presented at the last Workshop in Jakarta (25-28 Nov., 1996). This paper describes new research and applications carried out at Nuclear Physics Department of NRI after that time. They consist of neutron beam developments, neutron activation cross section measurements for waste disposal assessment and in-vivo prompt gamma neutron activation analysis for Cd determination in organs. After the last Sub-Workshop on Neutron Scattering in Serpong (21-23 Nov., 1996), we were accepted to participate in the Regional Program on Study of High Tc Superconductors with the topic `The mechanism of Pb and Sb dopant role on superconductivity of 2223 phase of Bi-Sr-Ca-Cu-O system`. Indeed, this study has begun at NRI only since August, 1997 due to the problem of materials. The study has been carried out in collaboration with the Hanoi State University (Superconductors Department) where experts and equipment for superconductors research have been considered as the best ones in Vietnam. Primary results in this study are presented in this workshop. (author)

  1. Development of 2-d position-sensitive neutron detector with individual readout. Operation test and establishment of detection system by means of neutron beam

    International Nuclear Information System (INIS)

    Tanaka, Hiroki; Yamagishi, Hideshi; Nakamura, Tatsuya; Soyama, Kazuhiko; Aizawa, Kazuya

    2005-04-01

    We have been developing the 2-d position-sensitive neutron detector with individual readout as next-generation-type detector system for neutron scattering experiments using intense pulsed neutron source. The detection system is designed to fulfill the specifications required for each neutron spectrometer, such as a count rate, efficiency, neutron/gamma-ray ratio, a spatial resolution and a size, by using suitable detector heads. The fundamental and imaging performances of the developed system assembled with a Multi-wire proportional counter head were evaluated using a collimated neutron beam. The system worked stably for long hours at the 4 He gas pressure of 5 atm with a mixture of 30% C 2 H 6 (0.26 atom 3 He) at gas gain of 450. The spatial resolutions were 1.4, 1.6 mm (FWHM) for a cathode- and a back strip- direction, respectively, considering a beam size. It was also confirmed that the spatial uniformity of the detection efficiency over the whole sensitive detection area was rather good, ±8% deviation from the average with the optimum discrimination level. (author)

  2. Calculation And Design Of A New Configuration For Radiation Shielding At Neutron Beam No.3 For Fundamental And Applied Researches

    International Nuclear Information System (INIS)

    Vuong Huu Tan; Tran Tuan Anh; Nguyen Kien Cuong; Nguyen Canh Hai; Nguyen Xuan Hai; Pham Ngoc Son; Ho Huu Thang

    2011-01-01

    The tangential horizontal channel of No. 3 of the Dalat Research Reactor has been opened and used during the 1990s. The utilizations of the thermal neutron beam at this channel were the Neutron Radiography and the Prompt Gamma Neutron Activation Analysis method (PGNAA). At present, the neutron beam used for nuclear structure data researches based on the Summing of Amplitude Coincident Pulses system (SACP). Beside, several related research equipments have been set up and operated for the research purposes. A renovation of the neutron channel, therefore, will play an important role in safe and effective utilizations of the neutron beam in fields of nuclear physic training and researches. A new configuration for radiation shielding has been simulated by MCNP code. The calculated results of dose rates for neutron and gamma at working positions are in range of dose rate limit. (author)

  3. Single-crystal filters for attenuating epithermal neutrons and gamma rays in reactor beams

    DEFF Research Database (Denmark)

    Rustad, B.M.; Als-Nielsen, Jens Aage; Bahnsen, A.

    1965-01-01

    Cross section of representative samples of bismuth and quartz were measured at room and liquid nitrogen temperatures over neutron energy range of 0.0007 to 2.0 ev to obtain data for design of single-crystal 32-cm bismuth filters for attenuating fast neutrons and γ-rays in reactor beams; filters may...

  4. Influence of Great East Japan Earthquake on neutron source station in J-PARC

    International Nuclear Information System (INIS)

    Sakai, Kenji; Sakamoto, Shinichi; Kinoshita, Hidetaka; Seki, Masakazu; Haga, Katsuhiro; Kogawa, Hiroyuki; Wakui, Takashi; Naoe, Takashi; Kasugai, Yoshimi; Tatsumoto, Hideki; Aso, Tomokazu; Hasegawa, Shoichi; Maekawa, Fujio; Oikawa, Kenichi; Ooi, Motoki; Watanabe, Akihiko; Teshigawara, Makoto; Meigo, Shin-ichiro; Ikezaki, Kiyomi; Akutsu, Atsushi; Harada, Masahide; Takada, Hiroshi; Futakawa, Masatoshi

    2012-03-01

    This report investigates the behavior, damage and restoration of each component in a neutron source station of the Materials and Life Science Experimental Facility (MLF) of J-PARC at the time of the Great East Japan Earthquake (M9.0) and verified the safety design for emergency accidents in the neutron source station. The neutron source station of the MLF at the J-PARC generates neutrons by injecting proton beams into a mercury target, and supplies to user experimental apparatuses. It consists of the mercury target, three moderators filled with supercritical hydrogen, reflectors, water cooling shields, a vessel filled with helium gas, neutron beam shutters, biological-shields and so on. In case of loss of their external electric power supply, a control function for the source station is kept by an emergency power supply. According to interlock sequences in an emergency, a signal for terminating the beam operation is transmitted, the circulators shut down automatically, and the hydrogen gas is released out of the building. On March 11 in 2011, strong shocks caused by the earthquake were observed all over Ibaraki prefecture. At the date, a status of the source station was ready for the restart of beam operation. In the MLF, after strong quakes were detected at the several instruments, the external power supply was lost, all of the circulators shut down automatically, and the hydrogen gas was released. The leakages of mercury, hydrogen and radio-activation gases did not occur. While, the quakes made gaps between the shield blocks and ruptured external pipe lines for compressed air and water by subsidence around the building. But significant damages to the components were not found though the pressure drop of compressed air lines influenced on the mercury target trolley lock system and pneumatic operation values. These results substantiated the validity of the safety design for emergency accidents in the neutron source station in the MLF, and suggested several points

  5. Preliminary shielding analysis in support of the CSNS target station shutter neutron beam stop design

    Institute of Scientific and Technical Information of China (English)

    ZHANG Bin; CHEN Yi-Xue; WANG Wei-Jin; YANG Shou-Hai; WU Jun; YIN Wen; LIANG Tian-Jiao; JIA Xue-Jun

    2011-01-01

    The construction of China Spallation Neutron Source (CSNS) has been initiated in Dongguan,Guangdong, China.Thus a detailed radiation transport analysis of the shutter neutron beam stop is of vital importance. The analyses are performed using the coupled Monte Carlo and multi-dimensional discrete ordinates method. The target of calculations is to optimize the neutron beamline shielding design to guarantee personal safety and minimize cost. Successful elimination of the primary ray effects via the two-dimensional uncollided flux and the first collision source methodology is also illustrated. Two-dimensional dose distribution is calculated. The dose at the end of the neutron beam line is less than 2.5μSv/h. The models have ensured that the doses received by the hall staff members are below the standard limit required.

  6. Implementation of a system for external audits beam radiation therapy in terms of reference no

    International Nuclear Information System (INIS)

    Alonso Samper, Jose Luis; Dominguez, Lourdes; Alert Silva, Jose; Alfonso Laguardia, Rodolfo; Larrinaga Cortina, Eduardo; Garcia Yip, Fernando; Rodriguez Machado, Jorge; Morales Lopez, Jorge Luis; Silvestre Patallo, Ileana

    2009-01-01

    This paper presents our experience in implementing a external audit system for radiotherapy beam in no reference conditions with the use of CIRS and a summary of the measurements with him made.This paper presents our experience in implementing a external audit system for radiotherapy beam in no reference conditions with the use of CIRS and a summary of the measurements with him made. Centers were audited with external beam high-energy Co-60, 6 MV and 15 MV and were considered 4 treatment planning systems (TPS): AMEPLAN, Theraplan Plus, Precise Plan and MIRS to calculate doses prescribed in each test case. All measurements were acquired by the audit team using the anthropomorphic phantom CIRS, Semiflex chamber PTW 31010 and PTW electrometer STATES. The implementation and development of the external audits of beams radiotherapy in terms of 'no reference' has brought an improvement in both clinical aspects of treatment and the radiation safety and the quality control, has given us greater confidence and for this reason we believe has become essential. (Author)

  7. MCNP simulation of the influence of the external moisture on low calorific value in the coal quality analysis by neutron

    International Nuclear Information System (INIS)

    Liu Dekun; Zhang Hongyu; Zhang Lihong; Dong Huan; Gu Deshan

    2012-01-01

    An important index in assessment of coal quality is low calorific value. Using neutron to analysis coal quality, the more the coal moisture content, especially the increasing of external moisture will reduce the low calorific value. The principle of coal quality analysis by neutron prompt Gamma-ray is introduced. The influence of the gamma count of the carbon element peak with increasing external moisture in coal samples was simulated using MCNP code. And discussed the reasons how external moisture content influence the calorific value. Simulation results indicate that with the increasing of external moisture in the coal samples, the gamma count of the carbon element peak dwindling, and the low calorific value reducing. The conclusion is : using neutrons method to analysis coal quality, the more external moisture content, the larger error of the measurement results of the carbon element, and will influence the calculation accuracy of the low calorific value. (authors)

  8. Accumulator ring lattice for the national spallation neutron source

    International Nuclear Information System (INIS)

    Gardner, C.J.; Lee, Y.Y.; Luccio, A.U.

    1997-01-01

    The Accumulator Ring for the proposed National Spallation Neutron Source (NSNS) is to accept a 1.03 millisecond beam pulse from a 1 GeV Proton Linac at a repetition rate of 60 Hz. For each beam pulse, 10 14 protons are to be accumulated via charge-exchange injection. A 295 nanosecond gap in the beam, maintained by an rf system, will allow for extraction to an external target for the production of neutrons by spallation. This paper describes the four-fold symmetric lattice that has been chosen for the ring. The lattice contains four long dispersion-free straight sections to accomodate injection, extraction, rf cavities, and beam scraping respectively. The four-fold symmetry allows for easy adjustment of the tunes and flexibility in the placement of correction elements, and ensures that potentially dangerous betatron structure resonances are avoided

  9. SU-F-T-183: Design of a Beam Shaping Assembly of a Compact DD-Based Boron Neutron Capture Therapy System

    Energy Technology Data Exchange (ETDEWEB)

    Hsieh, M; Liu, Y; Nie, L [Purdue University, West Lafayette, Indiana (United States)

    2016-06-15

    Purpose: To design a beam shaping assembly (BSA) to shape the 2.45-MeV neutrons produced by a deuterium-deuterium (DD) neutron generator and to optimize the beam output for boron neutron capture therapy of brain tumors Methods: MCNP is used for this simulation study. The simulation model consists of a neutron surface source that resembles an actual DD source and is surrounded by a BSA. The neutron source emits 2.45-MeV neutrons isotropically. The BSA is composed of a moderator, reflector, collimator and filter. Various types of materials and geometries are tested for each component to optimize the neutron output. Neutron characteristics are measured with an 2×2×2-cm{sup 3} air-equivalent cylinder at the beam exit. The ideal BSA is determined by evaluating the in-air parameters, which include epithermal neutron per source neutron, fast neutron dose per epithermal neutron, and photon dose per epithermal neutron. The parameter values are compared to those recommended by the IAEA. Results: The ideal materials for reflector and thermal neutron filter were lead and cadmium, respectively. The thickness for reflector was 43 cm and for filter was 0.5 mm. At present, the best-performing moderator has 25 cm of AlF{sub 3} and 5 cm of MgF{sub 2}. This layout creates a neutron spectrum that has a peak at approximately 10 keV and produces 1.35E-4 epithermal neutrons per source neutron per cm{sup 2}. Additional neutron characteristics, fast neutrons per epithermal neutron and photon per epithermal neutron, are still under investigation. Conclusion: Working is ongoing to optimize the final layout of the BSA. The neutron spectrum at the beam exit window of the final configuration will have the maximum number of epithermal neutrons and limited photon and fast neutron contaminations within the recommended values by IAEA. Future studies will also include phantom experiments to validate the simulation results.

  10. Measurement of neutron production by 500 MeV proton beam

    International Nuclear Information System (INIS)

    Hirayama, Hideo; Ban, Shuichi

    1981-01-01

    Measurement of high energy neutrons is difficult, because the cross section data are scarce, the cross section at high energy is usually small, and the monoenergetic neutrons are hardly obtained. At the National Laboratory for High Energy Physics (KEK), various threshold detectors have been used for high energy neutron measurement. A carbon detector is a standard detector for high energy neutrons, since the cross section of the C 12 (n, 2n) C 11 reaction is almost constant at higher energy than 20 MeV, and the data have been well known. The half-life of the product (C 11 ) is about 20 min, and other activities with longer half-life than 1 min are restricted to Be 7 and C 11 . As a carbon detector, a plastic scintillator is used, and the neutron spectra observed at the Booster Beam Dump Room of KEK are presented. The results of measurements were compared with the calculated results using a Monte Carlo code made at KEK. Agreement between both results was good. (Kato, T.)

  11. Neutronics Assessments for a RIA Fragmentation Line Beam Dump Concept

    CERN Document Server

    Boles, Jason; Reyes, Susana; Stein, Werner

    2005-01-01

    Heavy ion and radiation transport calculations are in progress for conceptual beam dump designs for the fragmentation line of the proposed Rare Isotope Accelerator (RIA). Using the computer code PHITS, a preliminary design of a motor-driven rotating wheel beam dump and adjacent downstream multipole has been modeled. Selected results of these calculations are given, including neutron and proton flux in the wheel, absorbed dose and displacements per atom in the hub materials, and heating from prompt radiation and from decay heat in the multipole.

  12. Multigroup and coupled forward-adjoint Monte Carlo calculation efficiencies for secondary neutron doses from proton beams

    International Nuclear Information System (INIS)

    Kelsey IV, Charles T.; Prinja, Anil K.

    2011-01-01

    We evaluate the Monte Carlo calculation efficiency for multigroup transport relative to continuous energy transport using the MCNPX code system to evaluate secondary neutron doses from a proton beam. We consider both fully forward simulation and application of a midway forward adjoint coupling method to the problem. Previously we developed tools for building coupled multigroup proton/neutron cross section libraries and showed consistent results for continuous energy and multigroup proton/neutron transport calculations. We observed that forward multigroup transport could be more efficient than continuous energy. Here we quantify solution efficiency differences for a secondary radiation dose problem characteristic of proton beam therapy problems. We begin by comparing figures of merit for forward multigroup and continuous energy MCNPX transport and find that multigroup is 30 times more efficient. Next we evaluate efficiency gains for coupling out-of-beam adjoint solutions with forward in-beam solutions. We use a variation of a midway forward-adjoint coupling method developed by others for neutral particle transport. Our implementation makes use of the surface source feature in MCNPX and we use spherical harmonic expansions for coupling in angle rather than solid angle binning. The adjoint out-of-beam transport for organs of concern in a phantom or patient can be coupled with numerous forward, continuous energy or multigroup, in-beam perturbations of a therapy beam line configuration. Out-of-beam dose solutions are provided without repeating out-of-beam transport. (author)

  13. Proceedings of neutron irradiation technical meeting on BNCT

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-10-01

    The 'Neutron Irradiation Technical Meeting for Boron Neutron Capture Therapy (BNCT)' was held on March 13, 2000 at Tokai Research Establishment. The Meeting is aimed to introduce the neutron beam facility for medical irradiation at JRR-4 to Japanese researchers widely, as well as providing an opportunity for young researchers, engineers, medical representatives such surgeons and doctors of pharmacology to present their research activities and to exchange valuable information. JAERI researcher presented the performance and the irradiation technology in the JRR-4 neutron beam facility, while external researchers made various and beneficial presentations containing such accelerator-based BNCT, spectrum-shifter, biological effect, pharmacological development and so on. In this meeting, a special lecture titled 'The Dawn of BNCT and Its Development.' was given by MD, Prof. Takashi Minobe, an executive director of Japan Foundation for Emergency Medicine. The 11 of the presented papers are indexed individually. (J.P.N.)

  14. RBE and clinical response in radiotherapy with neutron beams

    International Nuclear Information System (INIS)

    Ellis, F.

    1984-01-01

    Consideration of the clinical results reported, when a cyclotron produced neutron beam was used for treatments in the pelvis region, suggested that a constant RBE of 3 should not have been used for all neutron doses. Instead a variable RBE, which increased from approximately 3 to 8 (with decreasing dose), should have been used. Although some of these RBE values are much higher than 3, they have been observed in clinical practice. An ''equivalent photon'' isodose plan was produced by employing a variable RBE and, by taking a TDF limit of 86 for bowel, an isoeffect plan was produced. This shows that in the clinical situation under consideration much of the pelvis was overdosed. Doses to tumour cells and late effects are also briefly considered. It is suggested that, in neutron therapy, both an ''equivalent photon'' isodose plan and an isoeffect plan should be produced prior to treatment. (author)

  15. Basic quantum irreversibility in neutron interferometry

    International Nuclear Information System (INIS)

    Rauch, H

    2009-01-01

    The transition between the quantum and classical world is a topical problem in quantum physics, which can be investigated by neutron interferometric methods. Here we discuss unavoidable quantum losses as they appear in neutron phase-echo and spin rotation experiments and we show how entanglement effects in a single-particle system demonstrate quantum contextuality, i.e. an entanglement between external and internal degrees of freedom in single-particle systems. This contextuality phenomenon also shows that a quantum system carries much more information than usually extracted. In all cases of an interaction, parasitic beams are produced which cannot be recombined completely with the original beam. This means that a complete reconstruction of the original state is, in principle, impossible which causes a kind of intrinsic irreversibility. Even small interaction potentials can have huge effects when they are applied in quantum Zeno-like experiments. The path towards advanced neutron quantum optics will be discussed.

  16. Optimization of Neutron Spectrum in Northwest Beam Tube of Tehran Research Reactor for BNCT, by MCNP Code

    Energy Technology Data Exchange (ETDEWEB)

    Zamani, M. [National Radiation Protection Department - NRPD, Atomic Energy Organization of Iran - AEOI, Tehran (Iran, Islamic Republic of); End of North Kargar st, Atomic Energy Organization of Iran, P.O. Box: 14155-1339, Tehran (Iran, Islamic Republic of); Kasesaz, Y.; Khalafi, H.; Shayesteh, M. [Radiation Application School, Nuclear Science and Technology Research Institute, AEOI, Tehran (Iran, Islamic Republic of)

    2015-07-01

    In order to gain the neutron spectrum with proper components specification for BNCT, it is necessary to design a Beam Shape Assembling (BSA), include of moderator, collimator, reflector, gamma filter and thermal neutrons filter, in front of the initial radiation beam from the source. According to the result of MCNP4C simulation, the Northwest beam tube has the most optimized neuron flux between three north beam tubes of Tehran Research Reactor (TRR). So, it has been chosen for this purpose. Simulation of the BSA has been done in four above mentioned phases. In each stage, ten best configurations of materials with different length and width were selected as the candidates for the next stage. The last BSA configuration includes of: 78 centimeters of air as an empty space, 40 centimeters of Iron plus 52 centimeters of heavy-water as moderator, 30 centimeters of water or 90 centimeters of Aluminum-Oxide as a reflector, 1 millimeters of lithium (Li) as thermal neutrons filter and finally 3 millimeters of Bismuth (Bi) as a filter of gamma radiation. The result of Calculations shows that if we use this BSA configuration for TRR Northwest beam tube, then the best neutron flux and spectrum will be achieved for BNCT. (authors)

  17. Optimization of Neutron Spectrum in Northwest Beam Tube of Tehran Research Reactor for BNCT, by MCNP Code

    International Nuclear Information System (INIS)

    Zamani, M.; Kasesaz, Y.; Khalafi, H.; Shayesteh, M.

    2015-01-01

    In order to gain the neutron spectrum with proper components specification for BNCT, it is necessary to design a Beam Shape Assembling (BSA), include of moderator, collimator, reflector, gamma filter and thermal neutrons filter, in front of the initial radiation beam from the source. According to the result of MCNP4C simulation, the Northwest beam tube has the most optimized neuron flux between three north beam tubes of Tehran Research Reactor (TRR). So, it has been chosen for this purpose. Simulation of the BSA has been done in four above mentioned phases. In each stage, ten best configurations of materials with different length and width were selected as the candidates for the next stage. The last BSA configuration includes of: 78 centimeters of air as an empty space, 40 centimeters of Iron plus 52 centimeters of heavy-water as moderator, 30 centimeters of water or 90 centimeters of Aluminum-Oxide as a reflector, 1 millimeters of lithium (Li) as thermal neutrons filter and finally 3 millimeters of Bismuth (Bi) as a filter of gamma radiation. The result of Calculations shows that if we use this BSA configuration for TRR Northwest beam tube, then the best neutron flux and spectrum will be achieved for BNCT. (authors)

  18. Development of a monoenergetic neutron beam (Theoretical aspects, experimental developments and applications); Desarrollo de un haz de neutrones monoenergeticos (Aspectos teoricos, desarrollos experimentales y aplicaciones)

    Energy Technology Data Exchange (ETDEWEB)

    Varela G, A

    2003-07-01

    By the use of a neutron time of flight system at the Tandem Accelerator of the National Nuclear Research Institute; with neutrons provided by means of the {sup 2} H(d, n) {sup 3} He we intend to use the associated particle technique in order to have monoenergetic neutrons. This neutron beam will be used both in basic and applied research. (Author)

  19. A method to combine three dimensional dose distributions for external beam and brachytherapy radiation treatments for gynecological neoplasms

    International Nuclear Information System (INIS)

    Narayana, V.; Sahijdak, W.M.; Orton, C.G.

    1997-01-01

    Purpose: Radiation treatment of gynecological neoplasms, such as cervical carcinoma, usually combines external radiation therapy with one or more intracavitary brachytherapy applications. Although the dose from external beam radiation therapy and brachytherapy can be calculated and displayed in 3D individually, the dose distributions are not combined. At most, combined point doses are calculated for select points using various time-dose models. In this study, we present a methodology to combine external beam and brachytherapy treatments for gynecological neoplasms. Material and Methods: Three dimensional bio-effect treatment planning to obtain complication probability has been outlined. CT scans of the patient's pelvis with the gynecological applicator in place are used to outline normal tissue and tumor volumes. 3D external beam and brachytherapy treatment plans are developed separately and an external beam dose matrix and a brachytherapy dose matrix was calculated. The dose in each voxel was assumed to be homogeneous. The physical dose in each voxel of the dose matrix was then converted into extrapolated response dose (ERD) based on the linear quadratic model that accounts for the dose per fraction, number of fractions, dose rate, and complete or incomplete repair of sublethal damage (time between fractions). The net biological dose delivered was obtained by summing the ERD grids from external beam and brachytherapy since there was complete repair of sublethal damage between external beam and brachytherapy treatments. The normal tissue complication probability and tumor control probability were obtained using the biological dose matrix based on the critical element model. Results: The outlined method of combining external beam and brachytherapy treatments was implemented on gynecological treatments using an applicator for brachytherapy treatments. Conclusion: Implementation of the biological dose calculation that combine different modalities is extremely useful

  20. Prospective survey of erectile dysfunction after external beam radiotherapy for prostate cancer

    International Nuclear Information System (INIS)

    Kikuchi, Eiji; Ando, Toshiyuki; Nagata, Hirohiko; Miyajima, Akira; Nakagawa, Ken; Oya, Mototsugu; Nakashima, Jun; Marumo, Ken

    2011-01-01

    We prospectively evaluated the effect of external beam radiotherapy on erectile function in patients with localized or locally advanced prostate cancer using the Japanese version of the International Index of Erectile Function (IIEF) survey. From 2000 to 2007, we identified 55 patients who underwent external beam radiotherapy at our institution for localized or locally advanced prostate cancer and could respond to the IIEF survey. The patients did not receive neo- and/or adjuvant hormone therapy and they were followed-up for at least 12 months after radiotherapy. Mean patient age was 69 years and the mean prostate specific antigen (PSA) level before radiotherapy was 24.9 ng/ml. First we evaluated the change of the erectile function domain score over time before and after radiotherapy. The population of severe erectile dysfunction (ED) increased while those with no or mild ED decreased after radiotherapy. The erectile function and intercourse satisfaction domain score of the IIEF declined significantly after radiotherapy, however, the orgasmic function, sexual desire, and overall satisfaction domain scores did not change after external beam radiation. Of the 34 patients who had erectile function at baseline, 10 patients could maintain erectile function 12 months after radiotherapy. Though there were no significant differences in clinical features between patients who could maintain erectile function and those who had worsening erectile function 12 months after radiotherapy, the sexual desire domain score before radiotherapy was significantly higher in patients who could maintain erectile function than their counterparts. Using the IIEF survey, external beam radiation was found to affect erectile function in patients with localized or locally advanced prostate cancer. (author)

  1. Design of collimator in the radial piercing beam port of Kartini reactor for boron neutron capture therapy

    International Nuclear Information System (INIS)

    M Ilma Muslih A; Andang Widiharto; Yohannes Sardjono

    2014-01-01

    Studies were carried out to design a collimator which results in epithermal neutron beam for in vivo experiment of Boron Neutron Capture Therapy (BNCT) at the Kartini Research Reactor by means of Monte Carlo N-Particle (MCNP) codes. Reactor within 100 kW of thermal power was used as the neutron source. All materials used were varied in size, according to the value of mean free path for each material. MCNP simulations indicated that by using 5 cm thick of Ni (95%) as collimator wall, 15 cm thick of Al as moderator, 1 cm thick of Pb as γ-ray shielding, 1.5 cm thick of Boral as additional material, with 2 cm aperture diameter, epithermal neutron beam with maximum flux of 5.03 x 10 8 n.cm -2 .s -1 could be produced. The beam has minimum fast neutron and γ-ray components of, respectively, 2.17 x 10 -13 Gy.cm 2 .n -1 and 1.16 x 10 -13 Gy.cm 2 .n -l , minimum thermal neutron per epithermal neutron ratio of 0.12, and maximum directionality of 0.835 . It did not fully pass the IAEA's criteria, since the epithermal neutron flux was below the recommended value, 1.0 x 10 9 n.cm -2 .s -l . Nonetheless, it was still usable with epithermal neutron flux exceeding 5.0 x 10 8 n.cm -2 .s -1 and fast neutron flux close to 2 x 10 -13 Gy.cm 2 .n -1 it is still feasible for BNCT in vivo experiment. (author)

  2. Multi-beam neutron guide system at IRI, Delft

    Energy Technology Data Exchange (ETDEWEB)

    Well, A.A. van; Gibcus, H.P.M.; Gommers, R.M.; Haan, V.O. de; Labohm, F.; Verkooijen, A.H.M. [Technische Univ. Delft (Netherlands). Interfacultair Reactor Inst.; Schebetov, A.; Pusenkov, V. [St. Petersburg Inst. of Nuclear Physics, Gatchina (Russian Federation)

    2001-07-01

    One of the main facilities of the Interfaculty Reactor Institute (IRI) at the Delft University of Technology is the swimming-pool type research reactor HOR. In 1963 it was critical for the first time. The power raised from 100 kW in 1963 to 500 kW in 1965. In 1968, forced cooling was introduced. From that time on, the reactor is operated at 2 MW, 5 days per week. The reactor comprises a variety of irradiation facilities, used among others for radioisotope production and neutron activation analysis. It is equipped with six horizontal radial beam tubes, originally used for neutron-scattering experiments. Throughout the years, the research activities have grown steadily, both in the development of new techniques and in applying these techniques in new research areas. (orig.)

  3. Structural design study of a proton beam window for a 1-MW spallation neutron source

    CERN Document Server

    Teraoku, T; Ishikura, S; Kaminaga, M; Maekawa, F; Meigo, S I; Terada, A

    2003-01-01

    A 1-MW spallation neutron source aiming at materials and life science researches will be constructed under the JAERI-KEK High-intensity Proton Accelerator Project (J-PARC). A proton beam passes through a proton beam window, and be injected into a target of the neutron source. The proton beam window functions as a boundary wall between a high vacuum area in the proton beam line and a helium atmosphere at about atmospheric pressure in a helium vessel which contains the target and moderators. The proton beam window is cooled by light water because high heat-density is generated in the window material by interactions with the proton beam. Then, uniformity of the water flow is requested at the window to suppress a hot-spot that causes excessive thermal stress and cooling water boiling. Also, the window has to be strong enough in its structure for inner stress due to water pressure and thermal stress due to heat generation. In this report, we propose two types of proton beam windows; one flat-type that is easy to m...

  4. Study and production of polarized monochromatic thermal neutron beams; Etude et production de faisceaux monochromatiques polarises de neutrons lents

    Energy Technology Data Exchange (ETDEWEB)

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

    1963-06-15

    Results obtained with a recently built neutron spectrometer producing monochromatic polarized neutron beams,in the energy rang (10{sup -3} - 10) eV and using a series of artificial (Co: 92 per cent - Fe: 8 per cent) monocrystal as polarizers and analysers, are given. A high precision method for cutting monocrystals is explained. A description of the installation itself as well as some results obtained with Fe{sub 3}O{sub 4} crystals are also given. Experimental result pertaining to various magnetic guide and 'spin flip' system, as required in the handling of such polarized neutron beams, are also discussed. (author) [French] Nous donnons les resultats obtenus avec un spectrometre produisant des neutrons monochromatiques polarises d'energie comprise entre quelques milliemes d'electronvolts et quelques electronvotts qui utilise une serie de monocristaux artificiels de Co: 92 pour cent - Fe: 8 pour cent, comme polariseurs et analyseurs. Nous discutons egalement une methode de taille de monocristaux a tres haute precision. Le dispositif experimental ainsi que quelques resultats preliminaires obtenus avec des monocristaux de Fe{sub 3}O{sub 4} sont egalement donnes. Nous discutons egalement des resultats experimentaux obtenus avec differents systemes de guidage magnetique et de renversement du spin. (auteur)

  5. Study and production of polarized monochromatic thermal neutron beams; Etude et production de faisceaux monochromatiques polarises de neutrons lents

    Energy Technology Data Exchange (ETDEWEB)

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

    1963-06-15

    Results obtained with a recently built neutron spectrometer producing monochromatic polarized neutron beams,in the energy rang (10{sup -3} - 10) eV and using a series of artificial (Co: 92 per cent - Fe: 8 per cent) monocrystal as polarizers and analysers, are given. A high precision method for cutting monocrystals is explained. A description of the installation itself as well as some results obtained with Fe{sub 3}O{sub 4} crystals are also given. Experimental result pertaining to various magnetic guide and 'spin flip' system, as required in the handling of such polarized neutron beams, are also discussed. (author) [French] Nous donnons les resultats obtenus avec un spectrometre produisant des neutrons monochromatiques polarises d'energie comprise entre quelques milliemes d'electronvolts et quelques electronvotts qui utilise une serie de monocristaux artificiels de Co: 92 pour cent - Fe: 8 pour cent, comme polariseurs et analyseurs. Nous discutons egalement une methode de taille de monocristaux a tres haute precision. Le dispositif experimental ainsi que quelques resultats preliminaires obtenus avec des monocristaux de Fe{sub 3}O{sub 4} sont egalement donnes. Nous discutons egalement des resultats experimentaux obtenus avec differents systemes de guidage magnetique et de renversement du spin. (auteur)

  6. Dehydration process of fish analyzed by neutron beam imaging

    International Nuclear Information System (INIS)

    Tanoi, K.; Hamada, Y.; Seyama, S.; Saito, T.; Iikura, H.; Nakanishi, T.M.

    2009-01-01

    Since regulation of water content of the dried fish is an important factor for the quality of the fish, water-losing process during drying (squid and Japanese horse mackerel) was analyzed through neutron beam imaging. The neutron image showed that around the shoulder of mackerel, there was a part where water content was liable to maintain high during drying. To analyze water-losing process more in detail, spatial image was produced. From the images, it was clearly indicated that the decrease of water content was regulated around the shoulder part. It was suggested that to prevent deterioration around the shoulder part of the dried fish is an important factor to keep quality of the dried fish in the storage.

  7. First results of micro-neutron tomography by use of a focussing neutron lens

    CERN Document Server

    Masschaele, B; Cauwels, P; Dierick, M; Jolie, J; Mondelaers, W

    2001-01-01

    Since the appearance of high flux neutron beams, scientists experimented with neutron radiography. This high beam flux combined with modern neutron to visible light converters leads to the possibility of performing fast neutron micro-tomography. The first results of cold neutron tomography with a neutron lens are presented in this article. Samples are rotated in the beam and the projections are recorded with a neutron camera. The 3D reconstruction is performed with cone beam reconstruction software.

  8. SU-E-T-403: Evaluation of the Beam Performance of a Varian TrueBeam Linear Accelerator Under External Device-Based Gated Delivery Conditions

    International Nuclear Information System (INIS)

    Kobulnicky, K; Pawlak, D; Purwar, A

    2015-01-01

    Purpose: To examine the beam performance of a Varian TrueBeam linear accelerator under external device-based gated delivery conditions. Methods: Six gating cycles were used to evaluate the gating performance of a standard production TrueBeam system that was not specially tuned in any way. The system was equipped with a factory installed external gating interface (EXGI). An in-house EXGI tester box was used to simulate the input gating signals. The gating cycles were selected based on long beam-on and short beam-off times, short beam-on and long beam-off times, or equal beam on and off times to check linac performance. The beam latencies were measured as the time difference between the logic high gating signal and the first or last target pulses with an oscilloscope. Tissue-Phantom Ratio, beam flatness, and dose distributions from 5 different plans were measured using the 6 different gating durations and the un-gated irradiation. A PTW 729 2-D array was used to compare 5 plans versus the un-gated delivery with a 1%/1mm gamma index passing criteria. Results: The beam latencies of the linac were based off of 20 samples for beam-on and beam-off, for each gating cycle. The average beam-on delays were measured to be between 57 and 66msec, with a maximum of 88 msec. The beam off latencies averaged between 19 and 26msec, with a maximum of 48 msec. TPR20,10 measurements showed beam energy stability within 0.5% of the un-gated delivery. Beam flatness was better than 2.5% for all gated cycles. All but two deliveries, the open field with 4 seconds on, 1 second off, and a five field IMRT plan with 0.5 seconds on, 2.5 seconds off, had >90% passing rate. Conclusion: TrueBeam demonstrates excellent beam stability with minimal beam latencies under external device-based gated operations. Dosimetric measurements show minimal variation in beam energy, flatness, and plan delivery. Authors are employees of Varian Medical Systems, Inc

  9. SU-E-T-403: Evaluation of the Beam Performance of a Varian TrueBeam Linear Accelerator Under External Device-Based Gated Delivery Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Kobulnicky, K; Pawlak, D; Purwar, A [Varian Medical Systems, Inc., Palo Alto, CA (United States)

    2015-06-15

    Purpose: To examine the beam performance of a Varian TrueBeam linear accelerator under external device-based gated delivery conditions. Methods: Six gating cycles were used to evaluate the gating performance of a standard production TrueBeam system that was not specially tuned in any way. The system was equipped with a factory installed external gating interface (EXGI). An in-house EXGI tester box was used to simulate the input gating signals. The gating cycles were selected based on long beam-on and short beam-off times, short beam-on and long beam-off times, or equal beam on and off times to check linac performance. The beam latencies were measured as the time difference between the logic high gating signal and the first or last target pulses with an oscilloscope. Tissue-Phantom Ratio, beam flatness, and dose distributions from 5 different plans were measured using the 6 different gating durations and the un-gated irradiation. A PTW 729 2-D array was used to compare 5 plans versus the un-gated delivery with a 1%/1mm gamma index passing criteria. Results: The beam latencies of the linac were based off of 20 samples for beam-on and beam-off, for each gating cycle. The average beam-on delays were measured to be between 57 and 66msec, with a maximum of 88 msec. The beam off latencies averaged between 19 and 26msec, with a maximum of 48 msec. TPR20,10 measurements showed beam energy stability within 0.5% of the un-gated delivery. Beam flatness was better than 2.5% for all gated cycles. All but two deliveries, the open field with 4 seconds on, 1 second off, and a five field IMRT plan with 0.5 seconds on, 2.5 seconds off, had >90% passing rate. Conclusion: TrueBeam demonstrates excellent beam stability with minimal beam latencies under external device-based gated operations. Dosimetric measurements show minimal variation in beam energy, flatness, and plan delivery. Authors are employees of Varian Medical Systems, Inc.

  10. Generating AN Optimum Treatment Plan for External Beam Radiation Therapy.

    Science.gov (United States)

    Kabus, Irwin

    1990-01-01

    The application of linear programming to the generation of an optimum external beam radiation treatment plan is investigated. MPSX, an IBM linear programming software package was used. All data originated from the CAT scan of an actual patient who was treated for a pancreatic malignant tumor before this study began. An examination of several alternatives for representing the cross section of the patient showed that it was sufficient to use a set of strategically placed points in the vital organs and tumor and a grid of points spaced about one half inch apart for the healthy tissue. Optimum treatment plans were generated from objective functions representing various treatment philosophies. The optimum plans were based on allowing for 216 external radiation beams which accounted for wedges of any size. A beam reduction scheme then reduced the number of beams in the optimum plan to a number of beams small enough for implementation. Regardless of the objective function, the linear programming treatment plan preserved about 95% of the patient's right kidney vs. 59% for the plan the hospital actually administered to the patient. The clinician, on the case, found most of the linear programming treatment plans to be superior to the hospital plan. An investigation was made, using parametric linear programming, concerning any possible benefits derived from generating treatment plans based on objective functions made up of convex combinations of two objective functions, however, this proved to have only limited value. This study also found, through dual variable analysis, that there was no benefit gained from relaxing some of the constraints on the healthy regions of the anatomy. This conclusion was supported by the clinician. Finally several schemes were found that, under certain conditions, can further reduce the number of beams in the final linear programming treatment plan.

  11. Change of magnetic properties of nanocrystalline alloys under influence of external factors

    Science.gov (United States)

    Sitek, Jozef; Holková, Dominika; Dekan, Julius; Novák, Patrik

    2016-10-01

    Nanocrystalline (Fe3Ni1)81Nb7B12 alloys were irradiated using different types of radiation and subsequently studied by Mössbauer spectroscopy. External magnetic field of 0.5 T, electron-beam irradiation up to 4 MGy, neutron irradiation up to 1017 neutrons/cm2 and irradiation with Cu ions were applied on the samples. All types of external factors had an influence on the magnetic microstructure manifested as a change in the direction of the net magnetic moment, intensity of the internal magnetic field and volumetric fraction of the constituent phases. The direction of the net magnetic moment was the most sensitive parameter. Changes of the microscopic magnetic parameters were compared after different external influence and results of nanocrystalline samples were compared with their amorphous precursors.

  12. Beam plasma 14 MeV neutron source for fusion materials development

    International Nuclear Information System (INIS)

    Ravenscroft, D.; Bulmer, D.; Coensgen, F.; Doggett, J.; Molvik, A.; Souza, P.; Summers, L.; Williamson, V.

    1991-09-01

    The conceptual engineering design and expected performance for a 14 MeV DT neutron source is detailed. The source would provide an intense neutron flux for accelerated testing of fusion reactor materials. The 150-keV neutral beams inject energetic deuterium atoms, that ionize, are trapped, then react with a warm (200 eV), dense tritium target plasma. This produces a neutron source strength of 3.6 x 10 17 n/sec for a neutron power density at the plasma edge of 5--10 MW/m 2 . This is several times the ∼2 MW/m 2 anticipated at the first wall of fusion reactors. This high flux provides accelerated end-of-life tests of 1- to 2-year duration, thus making materials development possible. The modular design of the source and the facilities are described

  13. Epithermal neutron beam for BNCT research at the Washington State University TRIGA research reactor

    International Nuclear Information System (INIS)

    Nigg, D.W.; Venhuizen, J.R.; Wheeler, F.J.; Wemple, C.A.; Tripard, G.E.; Gavin, P.R.

    2000-01-01

    A new epithermal-neutron beam facility for BNCT (Boron Neutron Capture Therapy) research and boronated agent screening in animal models is in the final stages of construction at Washington State University (WSU). A key distinguishing feature of the design is the incorporation of a new, high-efficiency, neutron moderating and filtering material, Fluental, developed by the Technical Research Centre of Finland. An additional key feature is the provision for adjustable filter-moderator thickness to systematically explore the radiobiological consequences of increasing the fast-neutron contamination above the nominal value associated with the baseline system. (author)

  14. Suppression of beam-excited electron waves by an externally applied RF signal

    International Nuclear Information System (INIS)

    Fukumasa, Osamu; Itatani, Ryohei

    1980-11-01

    Suppression of the beam-excited electron wave in a bounded system is investigated in connection with the beam distribution function. Wave suppression has two different processes depending on whether injected beams are reflected at the other end or not. In the absence of reflected beam electrons, deformation of the beam distribution function is observed in relation to the suppression of the electron wave. However, when beam electrons are reflected, the external wave suppresses the electron wave but distribution function shows no appreciable change. These experimental results show that nonlinear behaviors of beam electrons, namely behaviors of reflected beams, are quite important for wave suppression. By using the method of partial simulation, interaction between two waves in the bounded system including nonlinear motions of beam electrons is studied numerically. Qualitative agreement between experimental and numerical results is obtained. (author)

  15. Fan analyzer of neutron beam polarization on REMUR spectrometer at IBR-2 pulsed reactor

    International Nuclear Information System (INIS)

    Nikitenko, Yu.V.; Ul'yanov, V.A.; Pusenkov, V.M.; Kozhevnikov, S.V.; Jernenkov, K.N.; Pleshanov, N.K.; Peskov, B.G.; Petrenko, A.V.; Proglyado, V.V.; Syromyatnikov, V.G.; Schebetov, A.F.

    2006-01-01

    The new spectrometer of polarized neutrons REMUR has been created and put in operation in the Frank Laboratory of Neutron Physics (JINR, Dubna). The spectrometer is dedicated to investigations of multiplayer structures and surfaces by registering the reflection of polarized neutrons and of the inhomogeneous state of solid matter by measuring the small-angle scattering of polarized neutrons. The spectrometer's working range of neutron wavelengths is 1.5-10 A. The spectrometer is equipped with a linear position-sensitive detector and a focused supermirror polarization analyzer (fan-like polarization analyzer) with a solid angle of neutron detection of 2.2x10 -4 rad. This article describes the design and the principle of operation of the fan analyzer of neutron polarization together with the results of its tests on a polarized neutron beam

  16. Scattering and depolarization of polarized neutrons in ferrofluids

    International Nuclear Information System (INIS)

    Balasoiu, M.; Dokukin, E.B.; Kozhevnikov, S.V.; Nikitenko, Y.V.

    1999-01-01

    On the SPN - 1 polarized neutron spectrometer at IBR -2 high - flux pulsed rector there were carried out preliminary measurements on transmission and polarization of a neutron beam passing through a magnetic colloidal system of Fe 3 O 4 particles in transformer oil and dodecane carriers. It was found that in the ferrofluids with magnetite particles exist, dependent on the particle volume concentration and the magnitude of the external magnetic field, effects of depolarization and nuclear - magnetic small angle scattering. (author)

  17. Photo neutron dose equivalent rate in 15 MV X-ray beam from a Siemens Primus Linac

    Directory of Open Access Journals (Sweden)

    A Ghasemi

    2015-01-01

    Full Text Available Fast and thermal neutron fluence rates from a 15 MV X-ray beams of a Siemens Primus Linac were measured using bare and moderated BF 3 proportional counter inside the treatment room at different locations. Fluence rate values were converted to dose equivalent rate (DER utilizing conversion factors of American Association of Physicist in Medicine′s (AAPM report number 19. For thermal neutrons, maximum and minimum DERs were 3.46 × 10 -6 (3 m from isocenter in +Y direction, 0 × 0 field size and 8.36 × 10 -8 Sv/min (in maze, 40 × 40 field size, respectively. For fast neutrons, maximum DERs using 9" and 3" moderators were 1.6 × 10 -5 and 1.74 × 10 -5 Sv/min (2 m from isocenter in +Y direction, 0 × 0 field size, respectively. By changing the field size, the variation in thermal neutron DER was more than the fast neutron DER and the changes in fast neutron DER were not significant in the bunker except inside the radiation field. This study showed that at all points and distances, by decreasing field size of the beam, thermal and fast neutron DER increases and the number of thermal neutrons is more than fast neutrons.

  18. Neutron contamination of Varian Clinac iX 10 MV photon beam using Monte Carlo simulation

    International Nuclear Information System (INIS)

    Yani, S; Haryanto, F; Arif, I; Tursinah, R; Rhani, M F; Soh, R C X

    2016-01-01

    High energy medical accelerators are commonly used in radiotherapy to increase the effectiveness of treatments. As we know neutrons can be emitted from a medical accelerator if there is an incident of X-ray that hits any of its materials. This issue becomes a point of view of many researchers. The neutron contamination has caused many problems such as image resolution and radiation protection for patients and radio oncologists. This study concerns the simulation of neutron contamination emitted from Varian Clinac iX 10 MV using Monte Carlo code system. As neutron production process is very complex, Monte Carlo simulation with MCNPX code system was carried out to study this contamination. The design of this medical accelerator was modelled based on the actual materials and geometry. The maximum energy of photons and neutron in the scoring plane was 10.5 and 2.239 MeV, respectively. The number and energy of the particles produced depend on the depth and distance from beam axis. From these results, it is pointed out that the neutron produced by linac 10 MV photon beam in a typical treatment is not negligible. (paper)

  19. An assessment of effective dose to staff in external beam radiotherapy

    International Nuclear Information System (INIS)

    Rawlings, D.J.; Nicholson, L.

    1997-01-01

    Radiation safety in external beam radiotherapy is governed by national legislation. Annual doses recorded by radiographers and others associated with external beam radiotherapy are typically much lower than the relevant dose limit. However, it is possible that larger doses might be received as a result of an accidental irradiation. In the event of a significant exposure resulting in a dose at or near a relevant dose limit, an accurate conversion has to be made from the dose meter reading to the limiting quantity. A method was devised to demonstrate ratios of effective dose to personal dose equivalent which might be anticipated in the even of an individual other than the patient being irradiated within a radiotherapy treatment room consisting of a linear accelerator. The variation of ratios obtained under different conditions is discussed. (author)

  20. Cluster-transfer reactions with radioactive beams: a spectroscopic tool for neutron-rich nuclei

    CERN Document Server

    AUTHOR|(CDS)2086156; Raabe, Riccardo; Bracco, Angela

    In this thesis work, an exploratory experiment to investigate cluster-transfer reactions with radioactive beams in inverse kinematics is presented. The aim of the experiment was to test the potential of cluster-transfer reactions at the Coulomb barrier, as a possible mean to perform $\\gamma$ spectroscopy studies of exotic neutron-rich nuclei at medium-high energies and spins. The experiment was performed at ISOLDE (CERN), employing the heavy-ion reaction $^{98}$Rb + $^{7}$Li at 2.85 MeV/A. Cluster-transfer reaction channels were studied through particle-$\\gamma$ coincidence measurements, using the MINIBALL Ge array coupled to the charged particle Si detectors T-REX. Sr, Y and Zr neutron-rich nuclei with A $\\approx$ 100 were populated by either triton- or $\\alpha$ transfer from $^{7}$Li to the beam nuclei and the emitted complementary charged fragment was detected in coincidence with the $\\gamma$ cascade of the residues, after few neutrons evaporation. The measured $\\gamma$ spectra were studied in detail and t...

  1. Guide for External Beam Radiotherapy. Procedures 2007

    International Nuclear Information System (INIS)

    Ardiet, Jean-Michel; Bourhis, Jean; Eschwege, Francois; Gerard, Jean-Pierre; Martin, Philippe; Mazeron, Jean-Jacques; Barillot, Isabelle; Bey, Pierre; Cosset, Jean-Marc; Thomas, Olivier; Bolla, Michel; Bourguignon, Michel; Godet, Jean-Luc; Krembel, David; Valero, Marc; Bara, Christine; Beauvais-March, Helene; Derreumaux, Sylvie; Vidal, Jean-Pierre; Drouard, Jean; Sarrazin, Thierry; Lindecker-Cournil, Valerie; Robin, Sun Hee Lee; Thevenet, Nicolas; Depenweiller, Christian; Le Tallec, Philippe; Ortholan, Cecile; Aimone, Nicole; Baldeschi, Carine; Cantelli, Andree; Estivalet, Stephane; Le Prince, Cyrille; QUERO, Laurent; Costa, Andre; Gerard, Jean-Pierre; Ardiet, Jean-Michel; Bensadoun, Rene-Jean; Bourhis, Jean; Calais, Gilles; Lartigau, Eric; Ginot, Aurelie; Girard, Nicolas; Mornex, Francoise; Bolla, Michel; Chauvet, Bruno; Maingon, Philippe; Martin, Etienne; Azria, David; Gerard, Jean-Pierre; Grehange, Gilles; Hennequin, Christophe; Peiffert, Didier; Toledano, Alain; Belkacemi, Yazid; Courdi, Adel; Belliere, Aurelie; Peignaux, Karine; Mahe, Marc; Bondiau, Pierre-Yves; Kantor, Guy; Lepechoux, Cecile; Carrie, Christian; Claude, Line

    2007-01-01

    In order to optimize quality and security in the delivery of radiation treatment, the French SFRO (Societe francaise de radiotherapie oncologique) is publishing a Guide for Radiotherapy. This guide is realized according to the HAS (Haute Autorite de sante) methodology of 'structured experts consensus'. This document is made of two parts: a general description of external beam radiation therapy and chapters describing the technical procedures of the main tumors to be irradiated (24). For each procedure, a special attention is given to dose constraints in the organs at risk. This guide will be regularly updated

  2. Neutron polarization measurements using the pulsed-polarized proton and deuteron beams at TUNL

    International Nuclear Information System (INIS)

    Walter, R.L.

    1981-01-01

    Nanosecond wide pulses of polarized protons or deuterons at a repetition rate of 4 MHz are now routinely available for studying interactions involving outgoing neutrons. Up to 90 nA of protons and 200 nA of deuterons have been observed on target. The authors' first experiments involved the determination of the analyzing power A /SUB y/ (UJ) for a few (→p,n) and (→d,n) reactions using conventional neutron time-of-flight detection. A major program for observing polarization effects in neutron elastic scattering has been initiated. The source of polarized neutrons for this program is the 2 H(→d,n→) 3 He reaction which yields a neutron beam having 90% of the polarization of the incident deuterons

  3. Nuclear studies at TUNL using polarized neutron beams

    International Nuclear Information System (INIS)

    Walter, R.L.; Howell, C.R.; Tornow, W.

    1992-01-01

    Experimental data obtained using polarized neutron beams has proven to be essential for determining the nucleon-nucleon and the nucleon-nucleus interaction. The present paper reviews the experimental methods and some results of the Triangle Universities Nuclear Laboratory for a variety of polarization experiments involving neutron elastic scattering. A brief introduction to the nucleon-nucleon problem and its relation to the three-nucleon problem is presented; data for n-p and n-d analyzing powers are highlighted. Measurements involving heavier targets ( 93 Nb and 208 Pb) and their connection to the development of conventional and dispersive optical models are shown. The importance of the dispersive model for 27 Al in relation to conclusions about the nucleon-nucleus spin-spin potential is presented. Comparisons of microscopic models to data for 10 B and 28 Si are described

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1989-01-01

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

  5. Practical implications of the ICRP - Publication 26 on the neutron external monitoring

    International Nuclear Information System (INIS)

    Sordi, G.-M.A.A.

    1983-01-01

    The following topics are dealt with: radiation monitoring (monitoring of the work place, individual monitoring, application of models to the interpretation of the monitoring results, monitoring complementary functions); monitoring of the work place for the external neutronic radiation (a project for a monitoring program, interpretation of the results) and confidence quality. (M.A.) [pt

  6. Initial performance of the Cornell cold neutron beam

    International Nuclear Information System (INIS)

    Clark, D.D.; Spern, S.A.; Atwood, A.G.

    1997-01-01

    The cold source for a guided neutron beam has been installed in a Cornell TRIGA beamport and has successfully undergone thermal tests up to full power (normally 480 kW). Tests to date (8/1/96) include spectral and yield measurements at 10 kW with the first three meters of the 2-cm by 5-cm Ni-on-glass guide in place. A 110-cm 3 Al chamber, located 17 cm from the core, contains solid mesitylene and is cooled by conduction through a 269-cm long Cu rod connected to a cryorefrigerator outside the reactor shield. Distributions of flux per unit velocity have been measured at 10 kW by time-of-flight. Anticipated properties of the complete 13 m long beam at full power are discussed. (author)

  7. The target volume concept at the recording of external beam radiotherapy

    International Nuclear Information System (INIS)

    Quast, U.; Glaeser, L.

    1981-01-01

    With the aim of complete, exact and reproducible manual recording and documentation of external beam radiotherapy a concept is proposed providing treatment planning and recording related to space and time for target volumes of different order corresponding to Ist, IInd or IIIrd part of treatment course, regarding all dose limiting organs at risk. The record consists of the dosage plan for medical treatment planning, the treatment plan for physical dose distribution planning and the treatment record of absorbed doses delivered as well as a checklist for patient and machine set-up, and labels for intended actions during treatment development. A clear arrangement of the record form in logical order was found, demanding exact specification of target(s) and beam(s) and their relation in space and time; asking for verbal and graphical description of target volumes, organs at risk, patient positioning, beam portals and dose reference points in terms of patients' anatomy; emphasizing the most important medical data by marked areas and leaving enough empty space for additional data, remarks or comments. During several years of clinical use these record forms proved to be suitable for all cases of external beam therapy, for complex situations of target volumes and treatment-scheduling, for all treatment techniques and radiation qualities and for all ways of physical treatment planning. They can be extended to automatic treatment verification, monitoring and recording as well as to the application of in-vivo-measurements of absorbed doses. (orig.) [de

  8. Pulsed and monoenergetic beams for neutron cross-section measurements using activation and scattering techniques at Triangle Universities Nuclear Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Hutcheson, A. [Triangle Universities Nuclear Laboratory, P.O. Box 90308, Durham, NC 27708 (United States)]. E-mail: hutch@tunl.duke.edu; Angell, C.T. [Triangle Universities Nuclear Laboratory, P.O. Box 90308, Durham, NC 27708 (United States); Becker, J.A. [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550 (United States); Boswell, M. [Triangle Universities Nuclear Laboratory, P.O. Box 90308, Durham, NC 27708 (United States); Crowell, A.S. [Triangle Universities Nuclear Laboratory, P.O. Box 90308, Durham, NC 27708 (United States); Dashdorj, D. [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550 (United States); Fallin, B. [Triangle Universities Nuclear Laboratory, P.O. Box 90308, Durham, NC 27708 (United States); Fotiades, N. [Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87545 (United States); Howell, C.R.; Karwowski, H.J.; Kelley, J.H.; Kiser, M. [Triangle Universities Nuclear Laboratory, P.O. Box 90308, Durham, NC 27708 (United States); Macri, R.A. [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550 (United States); Nelson, R.O. [Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87545 (United States); Pedroni, R.S. [NC A and T State University, 1601 East Market Street, Greensboro, NC 27411 (United States); Tonchev, A.P.; Tornow, W. [Triangle Universities Nuclear Laboratory, P.O. Box 90308, Durham, NC 27708 (United States); Vieira, D.J. [Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87545 (United States); Weisel, G.J. [Penn State Altoona, 3000 Ivyside Park, Altoona, PA 16601 (United States); Wilhelmy, J.B. [Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87545 (United States)

    2007-08-15

    In support of the Stewardship Science Academic Alliances initiative, an experimental program has been developed at Triangle Universities Nuclear Laboratory (TUNL) to measure (n,xn) cross-sections with both in-beam and activation techniques with the goal of improving the partial cross-section database for the NNSA Stockpile Stewardship Program. First experimental efforts include excitation function measurements on {sup 235,238}U and {sup 241}Am using pulsed and monoenergetic neutron beams with E {sub n} = 5-15 MeV. Neutron-induced partial cross-sections were measured by detecting prompt {gamma} rays from the residual nuclei using various combinations of clover and planar HPGe detectors in the TUNL shielded neutron source area. Complimentary activation measurements using DC neutron beams have also been performed in open geometry in our second target area. The neutron-induced activities were measured in the TUNL low-background counting area. In this presentation, we include detailed information about the irradiation procedures and facilities and preliminary data on first measurements using this capability.

  9. Improving the neutron-to-photon discrimination capability of detectors used for neutron dosimetry in high energy photon beam radiotherapy

    International Nuclear Information System (INIS)

    Irazola, L.; Terrón, J.A.; Bedogni, R; Pola, A.; Lorenzoli, M.; Sánchez-Nieto, B.; Gómez, F.; Sánchez-Doblado, F.

    2016-01-01

    The increasing interest of the medical community to radioinduced second malignancies due to photoneutrons in patients undergoing high-energy radiotherapy, has stimulated in recent years the study of peripheral doses, including the development of some dedicated active detectors. Although these devices are designed to respond to neutrons only, their parasitic photon response is usually not identically zero and anisotropic. The impact of these facts on measurement accuracy can be important, especially in points close to the photon field-edge. A simple method to estimate the photon contribution to detector readings is to cover it with a thermal neutron absorber with reduced secondary photon emission, such as a borated rubber. This technique was applied to the TNRD (Thermal Neutron Rate Detector), recently validated for thermal neutron measurements in high-energy photon radiotherapy. The positive results, together with the accessibility of the method, encourage its application to other detectors and different clinical scenarios. - Highlights: • Neutron-to-photon discrimination of a thermal neutron detector used in radiotherapy. • Photon and anisotropic response study with distance and beam incidence of thermal neutron detector. • Borated rubber for estimating photon contribution in any thermal neutron detector.

  10. Beam intensity increases at the intense pulsed neutron source accelerator

    International Nuclear Information System (INIS)

    Potts, C.; Brumwell, F.; Norem, J.; Rauchas, A.; Stipp, V.; Volk, G.

    1985-01-01

    The Intense Pulsed Neutron Source (IPNS) accelerator system has managed a 40% increase in time average beam current over the last two years. Currents of up to 15.6μA (3.25 x 10 12 protons at 30 Hz) have been successfully accelerated and cleanly extracted. Our high current operation demands low loss beam handling to permit hands-on maintenance. Synchrotron beam handling efficiencies of 90% are routine. A new H - ion source which was installed in March of 1983 offered the opportunity to get above 8 μA but an instability caused unacceptable losses when attempting to operate at 10 μA and above. Simple techniques to control the instabilities were introduced and have worked well. These techniques are discussed below. Other improvements in the regulation of various power supplies have provided greatly improved low energy orbit stability and contributed substantially to the increased beam current

  11. Elemental analysis with external-beam PIXE

    Science.gov (United States)

    Lin, E. K.; Wang, C. W.; Teng, P. K.; Huang, Y. M.; Chen, C. Y.

    1992-05-01

    A beamline system and experimental setup has been established for elemental analysis using PIXE with an external beam. Experiments for the study of the elemental composition of ancient Chinese potsherds (the Min and Ching ages) were performed. Continuum X-ray spectra from the samples bombarded by 3 MeV protons have been measured with a Si(Li) detector. From the analysis of PIXE data, the concentration of the main elements (Al, Si, K, and Ca) and of more than ten trace elements in the matrices and glazed surfaces were determined. Results for two different potsherds are presented, and those obtained from the glaze colorants are compared with the results of measurements on a Ching blue-and-white porcelain vase.

  12. Neutron flux stabilization in the NG-150 neutron generators

    International Nuclear Information System (INIS)

    Kuz'min, L.E.; Makarov, S.A.; Pronman, I.M.

    1986-01-01

    Problem of metal tritium target lifetime increase and neutron flux stabilization in the NG-150 neutron generators is studied. Possibility on neutron flux stabilization using the mass analyzer for low-angle (4 deg and 41 deg) mass separation of a beam in thre components, which fall on a target simultaneously, is confirmed experimentally. Basic generator parameters are: accelerating voltage of 150 kV, total beam current on a target of 1.5 mA, beam current density of 0.3-1.6 mA/cm 2 , beam diameter of 8 mm. The initial neutron flux on the targets of 0.73 mg/cm 2 thick constituted 1.1x10 11 ssup(-1). The neutron flux monitoring was accomplished from recoil proton recording by a plastic scintillator. Flux decrease by more than 5% served as a signel for measuring mass analyzer magnetic field providing beam displacement on a target and restoration of the given flux. The NG-150 generator neutron flux stabilization was attained during 2h

  13. A polarizing neutron periscope for neutron imaging

    International Nuclear Information System (INIS)

    Schulz, Michael; Boeni, Peter; Calzada, Elbio; Muehlbauer, Martin; Neubauer, Andreas; Schillinger, Burkhard

    2009-01-01

    Optical neutron polarizers like guides or benders destroy the collimation of a neutron beam due to multiple reflections or scattering. This makes them unsuitable for their use in polarized neutron radiography, because the beam collimation is essential to obtain high spatial resolution. We have developed a neutron polarizer based on the principle of an optical periscope with a zigzag double reflection on two parallel high-m supermirror polarizers. If the supermirrors are perfectly parallel and flat, the beam collimation is left unchanged by such a device. A first proof of concept version of this type of polarizer was built and tested. We expect to achieve a beam polarization of up to 99% with an improved version yet to be built.

  14. Determination of the total neutron cross section using average energy shift method for filtered neutron beam

    Directory of Open Access Journals (Sweden)

    О. О. Gritzay

    2016-12-01

    Full Text Available Development of the technique for determination of the total neutron cross sections from the measurements of sample transmission by filtered neutrons, scattered on hydrogen is described. One of the methods of the transmission determination TH52Cr from the measurements of 52Cr sample, using average energy shift method for filtered neutron beam is presented. Using two methods of the experimental data processing, one of which is presented in this paper (another in [1], there is presented a set of transmissions, obtained for different samples and for different measurement angles. Two methods are fundamentally different; therefore, we can consider the obtained processing results, using these methods as independent. In future, obtained set of transmissions is planned to be used for determination of the parameters E0, Гn and R/ of the resonance 52Cr at the energy of 50 keV.

  15. Absolute calibration of neutron detectors on the C-2U advanced beam-driven FRC

    Energy Technology Data Exchange (ETDEWEB)

    Magee, R. M., E-mail: rmagee@trialphaenergy.com; Clary, R.; Korepanov, S.; Jauregui, F.; Allfrey, I.; Garate, E.; Valentine, T.; Smirnov, A. [Tri Alpha Energy, Inc., Rancho Santa Margarita, California 92688 (United States)

    2016-11-15

    In the C-2U fusion energy experiment, high power neutral beam injection creates a large fast ion population that sustains a field-reversed configuration (FRC) plasma. The diagnosis of the fast ion pressure in these high-performance plasmas is therefore critical, and the measurement of the flux of neutrons from the deuterium-deuterium (D-D) fusion reaction is well suited to the task. Here we describe the absolute, in situ calibration of scintillation neutron detectors via two independent methods: firing deuterium beams into a high density gas target and calibration with a 2 × 10{sup 7} n/s AmBe source. The practical issues of each method are discussed and the resulting calibration factors are shown to be in good agreement. Finally, the calibration factor is applied to C-2U experimental data where the measured neutron rate is found to exceed the classical expectation.

  16. Design of a high-current low-energy beam transport line for an intense D-T/D-D neutron generator

    International Nuclear Information System (INIS)

    Lu, Xiaolong; Wang, Junrun; Zhang, Yu; Li, Jianyi; Xia, Li; Zhang, Jie; Ding, Yanyan; Jiang, Bing; Huang, Zhiwu; Ma, Zhanwen; Wei, Zheng; Qian, Xiangping; Xu, Dapeng; Lan, Changlin; Yao, Zeen

    2016-01-01

    An intense D-T/D-D neutron generator is currently being developed at the Lanzhou University. The Cockcroft–Walton accelerator, as a part of the neutron generator, will be used to accelerate and transport the high-current low-energy beam from the duoplasmatron ion source to the rotating target. The design of a high-current low-energy beam transport (LEBT) line and the dynamics simulations of the mixed beam were carried out using the TRACK code. The results illustrate that the designed beam line facilitates smooth transportation of a deuteron beam of 40 mA, and the number of undesired ions can be reduced effectively using two apertures.

  17. Investigation of the combined effect of neutron irradiation and electron beam exposure on pure tungsten

    Energy Technology Data Exchange (ETDEWEB)

    Van Renterghem, W., E-mail: wvrenter@sckcen.be; Uytdenhouwen, I., E-mail: iuytdenh@sckcen.be

    2016-08-15

    Pure tungsten samples were neutron irradiated in the BR2 reactor of SCK·CEN to fluences of 1.47 × 10{sup 20} n/cm{sup 2} and 4.74 × 10{sup 20} n/cm{sup 2} at 300 °C under Helium atmosphere and exposed to the electron beam of the Judith 1 installation The effect of these treatments on the defect structure was studied with transmission electron microscopy. In the irradiated samples the defect structure in the bulk is compared to the structure at the surface. The neutron irradiation created a large amount of a/2‹111› type dislocation loops forming dislocation rafts. The loop density increased from 8.5 × 10{sup 21}/m³ to 9 × 10{sup 22}/m³ with increasing dose, while the loop size decreased from 5.2 nm to 3.5 nm. The electron beam exposure induced significant annealing of the defects and almost all of the dislocation loops were removed. The number of line dislocations in that area increased as a result of the thermal stresses from the thermal shock. - Highlights: • Neutron irradiated and electron beam exposed tungsten samples were studied with transmission electron microscopy. • Neutron irradiation creates dislocation loops and rafts, while voids are created at higher irradiation dose. • No precipitates of transmutation products were found under these low dose irradiation conditions. • Electron beam exposure annihilates the dislocation loops and rafts.

  18. 3D FE Analysis of RC Beams Externally Strengthened with SRG/SRP Systems

    Directory of Open Access Journals (Sweden)

    Francesco Bencardino

    2016-05-01

    Full Text Available The purpose of this study is to evaluate, through a nonlinear Finite Element (FE analysis, the structural behavior of Reinforced Concrete (RC beams externally strengthened by using Steel Reinforced Grout (SRG and Steel Reinforced Polymer (SRP systems. The parameters taken into account were the external strengthening configuration, with or without U-wrap end anchorages, as well as the strengthening materials. The numerical simulations were carried out by using a three-dimensional (3D FE model. The linear and nonlinear behavior of all materials was modeled by appropriate constitutive laws and the connection between concrete substrate and external reinforcing layer was simulated by means of cohesive surfaces with appropriate bond-slip laws. In order to overcome convergence difficulties, to simulate the quasi-static response of the strengthened RC beams, a dynamic approach was adopted. The numerical results in terms of load-displacement curves, failure modes, and load and strain values at critical stages were validated against some experimental data. As a result, the proposed 3D FE model can be used to predict the structural behavior up to ultimate stage of similar strengthened beams without carrying out experimental tests.

  19. MO-A-BRB-03: Integration Issues in Electronic Charting for External Beam Therapy

    International Nuclear Information System (INIS)

    Sutlief, S.

    2015-01-01

    The process of converting to an electronic chart for radiation therapy can be daunting. It requires a dedicated committee to first research and choose appropriate software, to review the entire documentation policy and flow of the clinic, to convert this system to electronic form or if necessary, redesign the system to more easily conform to the electronic process. Those making the conversion and those who already use electronic charting would benefit from the shared experience of those who have been through the process in the past. Therefore TG262 was convened to provide guidance on electronic charting for external beam radiation therapy and brachytherapy. This course will present the results of an internal survey of task group members on EMR practices in External Beam Radiation Therapy as well as discuss important issues in EMR development and structure for both EBRT and brachytherapy. Learning Objectives: Be familiarized with common practices and pitfalls in development and maintenance of an electronic chart in Radiation Oncology Be familiarized with important issues related to electronic charting in External Beam Radiation Therapy Be familiarized with important issues related to electronic charting in Brachytherapy

  20. Californium-252 Brachytherapy Combined With External-Beam Radiotherapy for Cervical Cancer: Long-Term Treatment Results

    International Nuclear Information System (INIS)

    Lei Xin; Qian Chengyuan; Qing Yi; Zhao Kewei; Yang Zhengzhou; Dai Nan; Zhong Zhaoyang; Tang Cheng; Li Zheng; Gu Xianqing; Zhou Qian; Feng Yan; Xiong Yanli; Shan Jinlu; Wang Dong

    2011-01-01

    Purpose: To observe, by retrospective analysis, the curative effects and complications due to californium-252 ( 252 Cf) neutron intracavitary brachytherapy (ICBT) combined with external-beam radiotherapy (EBRT) in the treatment of cervical cancer. Methods and Materials: From February 1999 to December 2007, 696 patients with cervical cancer (Stages IB to IIIB) were treated with 252 Cf-ICBT in combination of EBRT. Of all, 31 patients were at Stage IB, 104 at IIA, 363 at IIB, 64 at IIIA, and 134 at IIIB. Californium-252 ICBT was delivered at 7–12 Gy per insertion per week, with a total dose of 29–45 Gy to reference point A in three to five insertions. The whole pelvic cavity was treated with 8-MV X-ray external irradiation at 2 Gy per fraction, four times per week. After 16–38 Gy of external irradiation, the center of the whole pelvic field was blocked with a 4-cm-wide lead shield, with a total external irradiation dose of 44–56 Gy. The total treatment course was 5 to 6 weeks. Results: Overall survival rate at 3 and 5 years for all patients was 76.0% and 64.9%, respectively. Disease-free 3- and 5-year survival rates of patients were 71.2% and 58.4%, respectively. Late complications included vaginal contracture and adhesion, radiation proctitis, radiation cystitis, and inflammatory bowel, which accounted for 5.8%, 7.1%, 6.2%, and 4.9%, respectively. Univariate analysis results showed significant correlation of stage, age, histopathologic grade, and lymph node status with overall survival. Cox multiple regression analysis showed that the independent variables were stage, histopathologic grade, tumor size, and lymphatic metastasis in all patients. Conclusion: Results of this series suggest that the combined use of 252 Cf-ICBT with EBRT is an effective method for treatment of cervical cancer.

  1. In-vivo dosimetric study of carcinoma of uterine cervix with FBX solution in external beam therapy

    International Nuclear Information System (INIS)

    Srinivas, Challapalli; Shenoy, K. Kamalaksh; Dinesh, M.; Savitha, K.S.; Kasturi, Dinesh Pai; Supe, S.S.; Nagesha, Y.N.

    1999-01-01

    To ensure accurate dose delivery to target site in external beam therapy and brachytherapy, various authors have conducted tests to assess the process of manual dose calculations. In vivo dosimetric measurement is one of these methods to verify these calculations. In this study, an attempt has been made to compare the manually calculated dose to dose estimated using a chemical dosimeter (FBX) solution (in-vivo method, using polypropylene vials), on 12 patients of carcinoma of uterine cervix in external beam therapy. Dose measured by FBX vial varies in the range of ± 2 to 6.75%, as compared with manual calculations. These variations seen may be attributed to the location of the vial position in the vagina, with reference to the beam axis (may not be horizontal), off axis position, manual calculation variations and reproducibility of the FBX system etc. FBX dosimetry offers itself as an in-vivo method to estimate the dose delivered to the target site in external beam therapy. (author)

  2. Neutron beams for therapy

    International Nuclear Information System (INIS)

    Kuplenikov, Eh.L.; Dovbnya, A.N.; Telegin, Yu.N.; Tsymbal, V.A.; Kandybej, S.S.

    2011-01-01

    It was given the analysis and generalization of the study results carried out during some decades in many world countries on application of thermal, epithermal and fast neutrons for neutron, gamma-neutron and neutron-capture therapy. The main attention is focused on the practical application possibility of the accumulated experience for the base creation for medical research and the cancer patients effective treatment.

  3. Coulomb Excitation of a Neutron-Rich $^{88}$Kr Beam Search for Mixed Symmetry States

    CERN Multimedia

    Andreoiu, C; Napiorkowski, P J; Iwanicki, J S

    2002-01-01

    We propose to use the ISOLDE/REX/MINIBALL/CD set-up to perform a Coulomb Excitation experiment with a $^{88}$Kr radioactive beam. The motivation includes a search for $Mixed$ $Symmetry$ states predicted by the IBM-2 model, gathering more spectroscopy data about the $^{88}$Kr nucleus and extending shape coexistence studies (performed previously by the proposers for neutron-deficient Kr isotopes) to the neutron-rich side. The proposed experiment will provide data complementary to the Coulomb Excitation of a relativistic $^{88}$Kr beam proposed by D. Tonev et al. for a RISING experiment. A total of 12 days of beam time is necessary for the experiment, equally divided into two runs. One run with a 2.2 MeV/A beam energy on a $^{48}$Ti target and a second run with the maximum available REX energy of 3.1 MeV/A on a $^{208}$Pb target are requested. Using either a UC$_{x}$ or ThC$_{x}$ fissioning primary target coupled with a plasma source by a cooled transfer line seems to be the best choice for the proposed experime...

  4. Neutron therapy

    International Nuclear Information System (INIS)

    Riesler, Rudi

    1995-01-01

    Standard radiotherapy uses Xrays or electrons which have low LET (linear energy transfer); in contrast, particles such as neutrons with high LET have different radiobiological responses. In the late 1960s, clinical trials by Mary Catterall at the Hammersmith Hospital in London indicated that fast neutron radiation had clinical advantages for certain malignant tumours. Following these early clinical trials, several cyclotron facilities were built in the 1980s for fast neutron therapy, for example at the University of Washington, Seattle, and at UCLA. Most of these newer machines use extracted cyclotron proton beams in the range 42 to 66 MeV with beam intensities of 15 to 60 microamps. The proton beams are transported to dedicated therapy rooms, where neutrons are produced from beryllium targets. Second-generation clinical trials showed that accurate neutron beam delivery to the tumour site is more critical than for photon therapy. In order to achieve precise beam geometries, the extracted proton beams have to be transported through a gantry which can rotate around the patient and deliver beams from any angle; also the neutron beam outline (''field shape'') must be adjusted to extremely irregular shapes using a flexible collimation system. A therapy procedure has to be appropriately organized, with physicians, radiotherapists, nurses, medical physicists and other staff in attendance; other specialized equipment, such as CT or MRI scanners and radiation simulators must be made available. Neutron therapy is usually performed only in radiation oncology departments of major medical centres

  5. Evaluation of GafChromic EBT prototype B for external beam dose verification

    International Nuclear Information System (INIS)

    Todorovic, M.; Fischer, M.; Cremers, F.; Thom, E.; Schmidt, R.

    2006-01-01

    The capability of the new GafChromic EBT prototype B for external beam dose verification is investigated in this paper. First the general characteristics of this film (dose response, postirradiation coloration, influence of calibration field size) were derived using a flat-bed scanner. In the dose range from 0.1 to 8 Gy, the sensitivity of the EBT prototype B film is ten times higher than the response of the GafChromic HS, which so far was the GafChromic film with the highest sensitivity. Compared with the Kodak EDR2 film, the response of the EBT is higher by a factor of 3 in the dose range from 0.1 to 8 Gy. The GafChromic EBT almost does not show a temporal growth of the optical density and there is no influence of the chosen calibration field size on the dose response curve obtained from this data. A MatLab program was written to evaluate the two-dimensional dose distributions from treatment planning systems and GafChromic EBT film measurements. Verification of external beam therapy (SRT, IMRT) using the above-mentioned approach resulted in very small differences between the planned and the applied dose. The GafChromic EBT prototype B together with the flat-bed scanner and MatLab is a successful approach for making the advantages of the GafChromic films applicable for verification of external beam therapy

  6. Development of high pressure deuterium gas targets for the generation of intense mono-energetic fast neutron beams

    International Nuclear Information System (INIS)

    Guzek, J.; Richardson, K.; Franklyn, C.B.; Waites, A.; McMurray, W.R.; Watterson, J.I.W.; Tapper, U.A.S.

    1999-01-01

    Two different technical solutions to the problem of generation of mono-energetic fast neutron beams on the gaseous targets are presented here. A simple and cost-effective design of a cooled windowed gas target system is described in the first part of this paper. It utilises a thin metallic foil window and circulating deuterium gas cooled down to 100 K. The ultimate beam handling capability of such target is determined by the properties of the window. Reliable performance of this gas target system was achieved at 1 bar of deuterium gas, when exposed to a 45 μA beam of 5 MeV deuterons, for periods in excess of 6 h. Cooling of the target gas resulted in increased fast neutron output and improved neutron to gamma-ray ratio. The second part of this paper discusses the design of a high pressure, windowless gas target for use with pulsed, low duty cycle accelerators. A rotating seal concept was applied to reduce the gas load in a differentially pumped system. This allows operation at 1.23 bar of deuterium gas pressure in the gas cell region. Such a gas target system is free from the limitations of the windowed target but special attention has to be paid to the heat dissipation capability of the beam dump, due to the use of a thin target. The rotating seal concept is particularly suitable for use with accelerators such as radio-frequency quadrupole (RFQ) linacs that operate with a very high peak current at low duty cycle. The performance of both target systems was comprehensively characterized using the time-of-flight (TOF) technique. This demonstrated that very good quality mono-energetic fast neutron beams were produced with the slow neutron and gamma-ray component below 10% of the total target output

  7. Optimization of the beam shaping assembly in the D-D neutron generators-based BNCT using the response matrix method.

    Science.gov (United States)

    Kasesaz, Y; Khalafi, H; Rahmani, F

    2013-12-01

    Optimization of the Beam Shaping Assembly (BSA) has been performed using the MCNP4C Monte Carlo code to shape the 2.45 MeV neutrons that are produced in the D-D neutron generator. Optimal design of the BSA has been chosen by considering in-air figures of merit (FOM) which consists of 70 cm Fluental as a moderator, 30 cm Pb as a reflector, 2mm (6)Li as a thermal neutron filter and 2mm Pb as a gamma filter. The neutron beam can be evaluated by in-phantom parameters, from which therapeutic gain can be derived. Direct evaluation of both set of FOMs (in-air and in-phantom) is very time consuming. In this paper a Response Matrix (RM) method has been suggested to reduce the computing time. This method is based on considering the neutron spectrum at the beam exit and calculating contribution of various dose components in phantom to calculate the Response Matrix. Results show good agreement between direct calculation and the RM method. Copyright © 2013 Elsevier Ltd. All rights reserved.

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

    International Nuclear Information System (INIS)

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

    2013-01-01

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

  9. Initial Experimental Verification of the Neutron Beam Modeling for the LBNL BNCT Facility

    International Nuclear Information System (INIS)

    Bleuel, D.L.; Chu, W.T.; Donahue, R.J.; Ludewigt, B.A.; McDonald, R.J.; Smith, A.R.; Stone, N.A.; Vuji, J.

    1999-01-01

    In preparation for future clinical BNCT trials, neutron production via the 7Li(p,n) reaction as well as subsequent moderation to produce epithermal neutrons have been studied. Proper design of a moderator and filter assembly is crucial in producing an optimal epithermal neutron spectrum for brain tumor treatments. Based on in-phantom figures-of-merit,desirable assemblies have been identified. Experiments were performed at the Lawrence Berkeley National Laboratory's 88-inch cyclotron to characterize epithermal neutron beams created using several microampere of 2.5 MeV protons on a lithium target. The neutron moderating assembly consisted of Al/AlF3 and Teflon, with a lead reflector to produce an epithermal spectrum strongly peaked at 10-20 keV. The thermal neutron fluence was measured as a function of depth in a cubic lucite head phantom by neutron activation in gold foils. Portions of the neutron spectrum were measured by in-air activation of six cadmium-covered materials (Au, Mn, In, Cu, Co, W) with high epithermal neutron absorption resonances. The results are reasonably reproduced in Monte Carlo computational models, confirming their validity

  10. A neutron irradiator applied to cancer treatment

    International Nuclear Information System (INIS)

    Campos, Tarcisio P.R.; Andrade, Ana P. de

    2000-01-01

    Cancer and the way of treating it with neutron capture therapy are addressed. This paper discusses also the type of neutron facilities used to treat cancer around the world, as follow: discrete neutron sources, accelerators, and nuclear reactors. The major features of an epithermal neutron irradiation facility applied to BNCT treatment are addressed. The main goal is to give another choice of neutron irradiators to be set in a hospital. The irradiation facility embeds a set of 252 Cf neutron source coupled with a homogeneous mixture of uranium-zirconium hydride alloy containing 8.4 wt % uranium enriched to 20% U 235 . The facility delivers an epithermal neutron beam with low background of fast neutron and gamma rays. The N particle transport code (MCNP-4A) has been used during the simulation in order to achieve the desired configurations and to estimate the multiplication factor, k eff . The present facility loaded with 30 mg of 252 Cf neutron source generates an external beam with an intensity of 10 7 n/cm 2 .s on the spectrum of 4 eV to 40 KeV. The 252 Cf - facility coupled with fissile material was able to amplify the epithermal flux to 10 8 n/cm 2 .s, maintaining the figure-of-merits represented by the ratios of the fast dose and gamma dose in air per epithermal neutron flux closed to those values presented by BMRR, MITR-II and Petten Reactor. The medical irradiation facility loaded with 252 Cf- 235 U can be a choice for BNCT. (author)

  11. Status report on treatment planning with the fast neutron beam at Hamburg-Eppendorf

    International Nuclear Information System (INIS)

    Hess, A.; Schmidt, R.; Franke, H.D.

    1981-01-01

    For treatment planning with the fast neutron beam (DT, 14 MeV) at the Radiotherapy Department of the University Hospital Hamburg-Eppendorf the decrement line method is applied to compute isodose curves (total beam or neutrons and gamma-rays separately). The isodose curves are generated by a measured depth dose distribution and one lateral dose distribution at 10 cm phantom depth assuming two crossing points of the decrement lines at the edges of the collimator. By this method isodose charts have been generated for all available field sizes at 80 cm SSD. For the determination of depth dose values at different SSD a modified inverse square law has to be taken into account. Computerized treatment plans are calculated with the same technique used by the SIDOS-U1 (Siemens) planning system. (orig.)

  12. A TCP model for external beam treatment of intermediate-risk prostate cancer.

    LENUS (Irish Health Repository)

    Walsh, Seán

    2013-03-01

    Biological models offer the ability to predict clinical outcomes. The authors describe a model to predict the clinical response of intermediate-risk prostate cancer to external beam radiotherapy for a variety of fractionation regimes.

  13. Study of very neutron-rich nuclei produced by means of a 48Ca beam

    International Nuclear Information System (INIS)

    Lewitowicz, M.; Artukh, A.G.

    1991-01-01

    The results of experiments with a 48 Ca beam performed at GANIL are presented and discussed. More than 30 very neutron-rich isotopes were identified or studied for the first time. The evidence for particle-unstable character of the 26 O isotope is reported. Half-life measurements for light neutron rich nuclei are compared with different theoretical predictions. (author) 14 refs.; 6 figs.; 1 tab

  14. Online monitoring of fast neutron (DT/DD) at Purnima neutron generator

    International Nuclear Information System (INIS)

    Bishnoi, S.; Patel, T.; Shukla, M.; Adhikari, P.S.; Sinha, A.

    2012-01-01

    A neutron generator (NG) at Purnima Labs, BARC has been developed for DT accelerator driven zero power subcritical (ADSS) system. Subcritical core of ADSS will be coupled to the NG for benchmarking experiments. Kinetic parameters of ADSS such as K-source, flux, power etc depends on this external neutron source strength injected to the core. However the neutron emission rate of NG does not remain stable throughout its operation. In view of this a reliable, precise and online monitoring of NG's neutron emission rate is required. An online neutron monitoring system based on associated particle method has been designed, developed and installed at NG. The monitoring unit consists of an ion implanted planar silicon detector, placed inside the drift tube of NG at an angle with respect to D + beam direction. A series of experiments were carried out with increasing neutron yield to optimize the position of detector such that it has sufficient counting statistics and minimum pileup. A complementary calibration procedure for validating these results based on activation technique was also carried out with standard Cu foil. The reaction rate monitored with online monitor and foil activation technique were compared, their variations with the predicted (theoretical) results were within 16%. This paper deals with the development and performance of online neutron monitoring system for DT and DD neutrons

  15. A neutron amplifier: prospects for reactor-based waste transmutation

    International Nuclear Information System (INIS)

    Blanovsky, A.

    2004-01-01

    A design concept and characteristics for an epithermal breeder controlled by variable feedback and external neutron source intensity are presented. By replacing the control rods with neutron sources, we could maintain good power distribution and perform radioactive waste burning in high flux subcritical reactors (HFSR) that have primary system size, power density and cost comparable to a pressurized water reactor (PWR). Another approach for actinide transmutation is a molten salt subcritical reactor proposed by Russian scientists. To increase neutron source intensity the HFSR is divided into two zones: a booster and a blanket with solid and liquid fuels. A neutron gate (absorber and moderator) imposed between two zones permits fast neutrons from the booster to flow to the blanket. Neutrons moving in the reverse direction are moderated and absorbed in the absorber zone. In the HFSR, neptunium-plutonium fuel is circulated in the booster and blanket, and americium-curium in the absorber zone and outer reflector. Use of a liquid actinide fuel permits transport of the delayed-neutron emitters from the blanket to the booster, where they can provide additional neutrons (source-dominated mode) or all the necessary excitation without an external neutron source (self-amplifying mode). With a blanket neutron multiplication gain of 20 and a booster gain of 50, an external neutron source rate of at least 10 15 n/s (0.7 MW D-T or 2.5 MW electron beam power) is needed to control the HFSR that produces 300 MWt. Most of the power could be generated in the blanket that burns about 100 kg of actinides a year. The analysis takes into consideration a wide range of HFSR design aspects including the wave model of observed relativistic phenomena, plant seismic diagnostics, fission electric cells (FEC) with a multistage collector (anode) and layered cathode. (author)

  16. Prompt gamma-ray analysis using JRR-3M cold and thermal neutron guide beams

    International Nuclear Information System (INIS)

    Yonezawa, C.; Haji Wood, A.K.; Magara, M.; Hoshi, M.; Tachikawa, E.; Sawahata, H.; Ito, Y.

    1993-01-01

    A permanent and stand-alone neutron-induced prompt gamma-ray analysis (PGA) system, usable at both cold and thermal neutron beam guides of JRR-3M has been constructed. Neutron flux at the sample positions were 1.4x10 8 and 2.4x10 7 n cm -2 s -1 for the cold and thermal neutrons, respectively. The γ-ray spectrometer is equipped to acquire three modes of spectra simultaneously: single mode, Compton suppression mode and pair mode, in an energy range up to 12 MeV. Owing to the cold neutron guide beam and the low γ-ray background system, analytical sensitivities and detection limits better than those in other PGA systems have been achieved. Analytical sensitivity and detection limit for 73 elements were measured. Boron, Gd, Sm and Cd are the most sensitive elements with detection limits down to 1 to 10 ng. For some elements such as F, Al, V, Eu and Hf, decay γ-rays are more sensitive compared to their respective prompt γ-ray. Analytical sensitivity of several heavy elements through detection of characteristic X-rays was higher than that through the prompt γ-ray detection. Analytical applicability of some sensitive elements such as B, H, Gd and Sm were examined. Isotopic analysis of Ni and Si were also examined. (author)

  17. Performance tests of external moderators of a PGNAA setup

    International Nuclear Information System (INIS)

    Naqvi, A.A.; Fazal-ur-Rehman,; Al-Jarallah, M.I.; Abu-Jarad, F.; Maslehuddin, M.

    2003-01-01

    Performance tests of external cylindrical moderators of an accelerator-based prompt gamma ray neutron activation analysis (PGNAA) setup have been carried out through thermal neutrons and prompt γ-ray yield measurements. The PGNAA setup is to be used for analysis of cement samples. This study was conducted to investigate the effects of geometry of cylindrical moderator on yield of thermal neutrons and prompt γ-rays for two different types of moderator assemblies. One of the moderators was to be used with a small sample and the other to be used with a large sample. Fast and thermal neutron yield was measured inside the sample volume as a function of the front moderator thickness as well as sample length. Neutron yield measurement was carried out at the King Fahd University of Petroleum and Minerals 350 keV pulsed beam accelerator using nuclear track detectors. The pulsed 200 keV deuteron beam with 5 ns pulse width and 31.25 kHz frequency was used to produce 2.8 MeV neutrons via D(d,n) reaction. Neutron yield measurements showed that the large sample moderator has a smaller yield of thermal neutrons as compared to the small sample moderator, which is in complete agreement with the results of Monte Carlo yield calculations of the thermal and fast neutrons from both the moderators. Finally, the prompt γ-ray yield from a Portland cement sample was measured using the two moderators and was compared with each other. As predicted by Monte Carlo simulations, in spite of a smaller yield of thermal neutrons, the large sample moderator has a higher yield of prompt γ-rays

  18. Performance tests of external moderators of a PGNAA setup

    Energy Technology Data Exchange (ETDEWEB)

    Naqvi, A.A. E-mail: aanaqvi@kfupm.edu.sa; Fazal-ur-Rehman,; Al-Jarallah, M.I.; Abu-Jarad, F.; Maslehuddin, M

    2003-01-01

    Performance tests of external cylindrical moderators of an accelerator-based prompt gamma ray neutron activation analysis (PGNAA) setup have been carried out through thermal neutrons and prompt {gamma}-ray yield measurements. The PGNAA setup is to be used for analysis of cement samples. This study was conducted to investigate the effects of geometry of cylindrical moderator on yield of thermal neutrons and prompt {gamma}-rays for two different types of moderator assemblies. One of the moderators was to be used with a small sample and the other to be used with a large sample. Fast and thermal neutron yield was measured inside the sample volume as a function of the front moderator thickness as well as sample length. Neutron yield measurement was carried out at the King Fahd University of Petroleum and Minerals 350 keV pulsed beam accelerator using nuclear track detectors. The pulsed 200 keV deuteron beam with 5 ns pulse width and 31.25 kHz frequency was used to produce 2.8 MeV neutrons via D(d,n) reaction. Neutron yield measurements showed that the large sample moderator has a smaller yield of thermal neutrons as compared to the small sample moderator, which is in complete agreement with the results of Monte Carlo yield calculations of the thermal and fast neutrons from both the moderators. Finally, the prompt {gamma}-ray yield from a Portland cement sample was measured using the two moderators and was compared with each other. As predicted by Monte Carlo simulations, in spite of a smaller yield of thermal neutrons, the large sample moderator has a higher yield of prompt {gamma}-rays.

  19. Nuclear analytical techniques with neutron beams at the Univ. of Texas at Austin

    International Nuclear Information System (INIS)

    Uenlue, K.; Wehring, B.W.

    1996-01-01

    Neutron beams produced by nuclear research reactors can be used for analytical chemical analysis by measuring nuclear radiation produced by neutron capture. Prompt gamma activation analysis (PGAA) and neutron depth profiling (NDP) are two such analytical techniques. For the last three decades, these techniques have been applied at a number of research reactors around the world. Within the last 4 yr, we have developed NDP and PGAA facilities at The University of Texas at Austin research reactor, a 1-MW TRIGA Mark II reactor. Brief descriptions of the facilities and summaries of activities for these analytical techniques at the University of Texas at Austin are provided in this paper

  20. Lattice design of medium energy beam transport line for n spallation neutron source

    International Nuclear Information System (INIS)

    Dhingra, Rinky; Kulkarni, Nita S.; Kumar, Vinit

    2015-01-01

    A 1 GeV H - injector linac is being designed at RRCAT for the proposed Indian Spallation Neutron Source (ISNS). The front-end of the injector linac will consist of Radiofrequency Quadrupole (RFQ) linac, which will accelerate the H - beam from 50 keV to 3 MeV. The beam will be further accelerated in superconducting Single Spoke Resonators (SSRs). A Medium Energy Beam Transport (MEBT) line will be used to transport the beam from the exit of RFQ to the input of SSR. The main purpose of MEBT is to carry out beam matching from RFQ to SSR, and beam chopping. In this paper, we describe the optimization criteria for the lattice design of MEBT. The optimized lattice element parameters are presented for zero and full (15 mA) current case. Beam dynamics studies have been carried out using an envelope tracing code Trace-3D. Required beam deflection angle due to the chopper housed inside the MEBT for beam chopping has also been estimated. (author)

  1. HYSPEC: A crystal time-of-flight hybrid spectrometer for the spallation neutron source with polarization capabilities

    International Nuclear Information System (INIS)

    Shapiro, S.M.; Zaliznyak, I.A.; Passell, L.; Ghosh, V.J.; Leonhardt, W.J.; Hagen, M.E.

    2006-01-01

    The hybrid spectrometer (HYSPEC) is a unique direct geometry inelastic scattering instrument under construction at the spallation neutron source (SNS). It combines the intensity enhancement features of focusing Bragg crystals with time-of-flight energy analysis. It will be located at beam-line 14B, which views a coupled liquid hydrogen moderator. A neutron beam from the moderator will travel along a curved guide, through a Fermi chopper and will then be focused onto a sample in an external building, 39 m from the source. In this configuration the intensity at the sample position is more than an order of magnitude larger than for other planned inelastic instrument. A movable detector bank 4.5 m from the sample will cover an angular range of 60 deg. in the horizontal plane and 15 deg. in the vertical direction. An important feature of HYSPEC is the ability to do neutron polarization analysis experiments. A Heusler crystal, which polarizes the neutron beam, can be used as the focusing crystal and a series of bender analyzers will analyze the polarization of the scattered beam

  2. External beam radiotherapy alone in advanced esophageal cancer

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Sung Ja; Chung, Woong Ki; Nah, Byung Sik; Nam, Taek Keun [College of Medicine, Chonnam National Univ., Kwangju (Korea, Republic of)

    1999-09-01

    We performed the retrospective analysis to find the outcome of external beam radiotherapy alone in advanced esophageal cancer patients. One hundred and six patients treated with external beam radiotherapy alone between July 1990 and December 1996 were analyzed retrospectively. We limited the site of the lesions to the thoracic esophagus and cell type to the squamous cell carcinoma. Follow-up was completed in 100 patients (94%) and ranged from 1 month to 92 months (median; 6 months). The median age was 62 years old and male to female ratio was 104:2. Fifty-three percent was the middle thorax lesion and curative radiotherapy was performed in 83%. Mean tumor dose delivered with curative aim was 58.6 Gy (55-70.8 Gy) and median duration of the radiation therapy was days. The median survival of all patients was 6 months and 1-year and 2-year overall survival rate was 27% and 12%, respectively. Improvement of dysphagia was obtained in most patients except for 7 patients who underwent feeding gastrostomy. The complete response rate immediately after radiation therapy was 32% (34/106). The median survival and 2-year survival rate of the complete responder was 14 months and 30% respectively, while those of the nonresponder was 4 months and 0% respectively (p=0.000). The median survival and 2-year survival rate of the patients who could tolerate regular diet was 9 months and 16% while those of the patients who could not tolerate regular diet was 3 months and 0%, respectively (p=0.004). The survival difference between the patients with 5 cm or less tumor length and those with more than 5 cm tumor length was marginally statistically significant (p=0.06). However, the survival difference according to the periesophageal invasion or mediastinal lymphadenopathy in the chest CT imaging study was not statistically significant in this study. In a multivariate analysis, the statistically significant covariates to the survival were complete response to radiotherapy, tumor, length, and

  3. Development Of A Method For Measurement Of Total Neutron Cross Sections Based On The Neutron Transmission Method Using A He-3 Counter On Filtered Neutron Beams At Dalat Research Reactor

    International Nuclear Information System (INIS)

    Tran Tuan Anh; Dang Lanh; Nguyen Canh Hai; Nguyen Xuan Hai; Pham Kien; Nguyen Thuy Nham; Pham Ngoc Son; Ho Huu Thang

    2007-01-01

    Determination of total neutron cross sections and average resonance parameters in the energy range from tens keV to hundreds keV is important for fast reactors calculations and designs because this energy range gives the most output of all neutron induced reactions in the spectrum of fast reactors. Besides, the total neutron cross section measurement is also one of the methods for determination of s, p and d-wave neutron strength functions. The purpose of this project is to develop a method for measurement of total neutron cross sections based on the neutron transmission technique using a He-3 counter. The average total neutron cross sections of 238 U were obtained from neutron transmission measurements on filtered neutron beams of 55 keV and 144 keV at the horizontal channel No.4 of the Dalat research reactor. The present results have been compared with the previous measurements, and the evaluated data from ENDF/B-6.8 library. (author)

  4. Influence of boost technique (external beam radiotherapy or brachytherapy) on the outcome of patients with carcinoma of the base of the tongue

    International Nuclear Information System (INIS)

    Regueiro, C.A.; Millan, I.; Torre, A. de la; Valcarcel, F.J.; Magallon, R.; Fernandez, E.; Aragon, G.

    1995-01-01

    We reviewed 90 patients with squamous cell carcinoma of the base of the tongue. Fifty-three patients were treated with external beam radiotherapy alone (3 T1, 11 T2, 21 T3, and 18 T4 tumors) and thirty-seven patients were treated with external beam radiotherapy plus brachytherapy boost (4 T1, 15 T2, 11 T3, and 7 T4 tumors). For patients with T1, T2 and T3 primaries, the actuarial 3-year local relapse-free survival was 42% following external beam radiotherapy alone and 67% following external beam radiotherapy plus brachytherapy (p<0.05). The actuarial 3-year cause specific survival for these T-stages was 37% for patients treated with external beam radiotherapy alone and 53% for patients treated with external beam radiotherapy plus brachytherapy (p=0.1). In the Cox multivariate analyses restricted patients with T1, T2 and T3 staged tumors, treatment modality was the only predictor for local control but no influence on specific survival was found. The trend towards significant differences in specific survival found in the univariate comparison of both treatment modalities was probably due to the significantly higher number of N-positive patients treated with external beam radiotherapy alone. When all stages were included in the Cox analysis, low hemoglobin level, invasion of deep muscle, number of palpable nodes, and history of weight loss significantly influenced the outcome. Soft tissue necrosis occurred more frequently in patients treated with external beam radiotherapy plus brachytherapy (33% vs. 10%, p=0.52). (orig.)

  5. Target volume delineation in external beam partial breast irradiation: less inter-observer variation with preoperative- compared to postoperative delineation

    NARCIS (Netherlands)

    Leij, F. van der; Elkhuizen, P.H.M.; Janssen, T.M.; Poortmans, P.M.P.; Sangen, M. van der; Scholten, A.N.; Vliet-Vroegindeweij, C. van; Boersma, L.J.

    2014-01-01

    The challenge of adequate target volume definition in external beam partial breast irradiation (PBI) could be overcome with preoperative irradiation, due to less inter-observer variation. We compared the target volume delineation for external beam PBI on preoperative versus postoperative CT scans of

  6. Designing an Epithermal Neutron Beam for Boron Neutron Capture Therapy for the Fusion Reactions 2H(d,n)3He and 3H(d,n)4He1

    International Nuclear Information System (INIS)

    Verbeke, J.M.; Costes, S.V.; Bleuel, D.; Vujic, J.; Leung, K.N.

    1998-01-01

    A beam shaping assembly has been designed to moderate high energy neutrons from the fusion reactions 2 H(d,N) 3 He and 3 H(d,n) 4 He for use fin boron neutron capture therapy. The low neutron yield of the 2 H(d,n) 3 He reaction led to unacceptably long treatment times. However, a 160 mA deuteron beam of energy 400 keV led to a treatment time of 120 minutes with the reaction 3 H(d,n) 4 He. Equivalent doses of 9.6 Gy-Eq and 21.9 Gy-Eq to the skin and to a 8 cm deep tumor respectively have been computed

  7. Neutron diagnostic that measures Z/sub eff/ in a neutral-beam-heated Tokomak

    International Nuclear Information System (INIS)

    Slaughter, D.R.

    1979-01-01

    The rate of pitch-angle scattering in a beam-driven Tokomak is proportional to Z/sub eff/ when neutral deuterium is injected parallel or antiparallel to the toroidal field B/sub T/. The energy spectrum of neutrons produced by D--D or D--T reactions is sensitive to the angular distribution of reacting energetic deuterons so that a measurement of the spectrum may be used to infer Z/sub eff/. Energy spectra of neutrons emitted parallel to B/sub T/ during simultaneous co- and counter-injection were calculated for the case of 120-keV beams by using a PPPL code. The results were then convoluted with spectrometer lineshapes determined experimentally for a system used to measure neutron spectra during a 1.0-s source pulse. Results indicate that Z/sub eff/ in the range of 1 to 4 may be determined with uncertainties of +- 0.25 for D--D plasma and +- 0.5 for D--T plasma, provided the ion temperature T/sub i/ is well known. However, the spectrometer energy resolution is not adequate to determine T/sub i/ directly from a neutron--spectrum measurement. In the absence of accurate T/sub i/ data, the uncertainty in Z/sub eff/ is approximately +- 1. In either case, impurity identification is not established by this type of measurement

  8. Characterisation of an accelerator-based neutron source for BNCT versus beam energy

    Science.gov (United States)

    Agosteo, S.; Curzio, G.; d'Errico, F.; Nath, R.; Tinti, R.

    2002-01-01

    Neutron capture in 10B produces energetic alpha particles that have a high linear energy transfer in tissue. This results in higher cell killing and a higher relative biological effectiveness compared to photons. Using suitably designed boron compounds which preferentially localize in cancerous cells instead of healthy tissues, boron neutron capture therapy (BNCT) has the potential of providing a higher tumor cure rate within minimal toxicity to normal tissues. This clinical approach requires a thermal neutron source, generally a nuclear reactor, with a fluence rate sufficient to deliver tumorcidal doses within a reasonable treatment time (minutes). Thermal neutrons do not penetrate deeply in tissue, therefore BNCT is limited to lesions which are either superficial or otherwise accessible. In this work, we investigate the feasibility of an accelerator-based thermal neutron source for the BNCT of skin melanomas. The source was designed via MCNP Monte Carlo simulations of the thermalization of a fast neutron beam, generated by 7 MeV deuterons impinging on a thick target of beryllium. The neutron field was characterized at several deuteron energies (3.0-6.5 MeV) in an experimental structure installed at the Van De Graaff accelerator of the Laboratori Nazionali di Legnaro, in Italy. Thermal and epithermal neutron fluences were measured with activation techniques and fast neutron spectra were determined with superheated drop detectors (SDD). These neutron spectrometry and dosimetry studies indicated that the fast neutron dose is unacceptably high in the current design. Modifications to the current design to overcome this problem are presented.

  9. Flexural Behavior of RC Members Using Externally Bonded Aluminum-Glass Fiber Composite Beams

    Directory of Open Access Journals (Sweden)

    Ki-Nam Hong

    2014-03-01

    Full Text Available This study concerns improvement of flexural stiffness/strength of concrete members reinforced with externally bonded, aluminum-glass fiber composite (AGC beams. An experimental program, consisting of seven reinforced concrete slabs and seven reinforced concrete beams strengthened in flexure with AGC beams, was initiated under four-point bending in order to evaluate three parameters: the cross-sectional shape of the AGC beam, the glass fiber fabric array, and the installation of fasteners. The load-deflection response, strain distribution along the longitudinal axis of the beam, and associated failure modes of the tested specimens were recorded. It was observed that the AGC beam led to an increase of the initial cracking load, yielding load of the tension steels and peak load. On the other hand, the ductility of some specimens strengthened was reduced by more than 50%. The A-type AGC beam was more efficient in slab specimens than in beam specimens and the B-type was more suitable for beam specimens than for slabs.

  10. Influence of the beam divergence on the quality neutron radiographic images improved by Richardson-Lucy deconvolution

    International Nuclear Information System (INIS)

    Almeida, Gevaldo L. de; Silvani, Maria Ines; Lopes, Ricardo T.

    2010-01-01

    Full text: Images produced by radiation transmission, as many others, are affected by disturbances caused by random and systematic uncertainties. Those caused by noise or statistical dispersion can be diminished by a filtering procedure which eliminates high-frequencies associated to the noise, but unfortunately also those belonging to the signal itself. Systematic uncertainties, in principle, could be more effectively removed if one knows the spoiling convolution function causing the degradation of the image. This function depends upon the detector resolution and the non-punctual character of the source employed in the acquisition, which blur the image making a single point to appear as a spot with a vanishing edge. For an extended source, exhibiting however a reasonable parallel beam, the penumbra degrading the image would be caused by the unavoidable beam divergence. In both cases, the essential information to improve the degraded image is the law of transformation of a single point into a blurred spot, known as point spread function-PSF. Even for an isotropic system, where this function would have a symmetric bell-like shape, it is very difficult to obtain experimentally and to apply it to the data processing. For this reason it is usually replaced by an approximated analytical function such as a Gaussian or Lorentzian. In this work, the Richardson-Lucy deconvoultion has been applied to ameliorate thermal neutron radiographic images acquired with imaging plates using a Gaussian PSF as deconvolutor. Due to the divergence of the neutron beam, reaching 1 deg 16', the penumbra affecting the final image depends upon the gap object-detector. Moreover, even if the object were placed in direct contact with the detector the non-zero dimension of the object along the beam path would produce penumbrae of different magnitudes, i.e., the spatial resolution of the system would be dependent upon the object-detector arrangement. This means that the width of the PSF increases

  11. Design and optimization of a beam-shaping assembly (BSA) for BNCT based on a neutron generator located at CEADEN, Havana, Cuba

    International Nuclear Information System (INIS)

    Padilla Cabal, F.; Martin, G; Abrahantes, A.

    2007-01-01

    A monoenergetic neutron beam simulation study is carried out to determine the most suitable neutron energy for treatment of shallow and deep-seated brain tumors in the context of Boron Neutron Capture Therapy (BNCT). Two figures-of-merit, i.e. the absorbed dose for healthy tissue and the absorbed tumor dose at a given depth in the brain are used to measure the neutron beam quality. Also irradiation time, therapeutic gain and the power generated in the target are utilized as beam assessment parameters. Moderators, reflectors and delimiters are designed and optimized to moderate the high-energy neutrons from the fusion reactions 2 H(d;n) 3 He and 3 H(d;n) 4 He down to a suitable energy spectrum. Metallic uranium and manganese are successfully tested for fast-to-epithermal neutron moderation as well as Fluental TM for the neutron spectrum shifting. A semispherical target is proposed in order to dissipate twice the amount of power generated in the target, and decrease all the dimensions of the BSA. The cooling system of the target is also included in the calculations. Calculations are performed using the MCNP code. After the optimization of our beam-shaper a study of the dose distribution in the head had been made. The therapeutic gain is increased in 9% while the current required for one hour treatment is decreased in comparison with the trading prototypes of NG used for BNCT. (Author)

  12. Design and optimization of a beam-shaping assembly (BSA) for BNCT based on a neutron generator located at CEADEN, Havana, Cuba

    International Nuclear Information System (INIS)

    Padilla Cabal, F.; Martin, G.; Abrahantes, A.

    2007-01-01

    A monoenergetic neutron beam simulation study is carried out to determine the most suitable neutron energy for treatment of shallow and deep-seated brain tumors in the context of Boron Neutron Capture Therapy (BNCT). Two figures-of-merit, i.e. the absorbed dose for healthy tissue and the absorbed tumor dose at a given depth in the brain are used to measure the neutron beam quality. Also irradiation time, therapeutic gain and the power generated in the target are utilized as beam assessment parameters. Moderators, reflectors and delimiters are designed and optimized to moderate the high-energy neutrons from the fusion reactions 2 H(d;n) 3 He and 3 H(d;n) 4 Hedown to a suitable energy spectrum. Metallic uranium and manganese are successfully tested for fast-to-epithermal neutron moderation as well as Fluental TM for the neutron spectrum shifting. A semi spherical target is proposed in order to dissipate twice the amount of power generated in the target, and decrease all the dimensions of the BSA. The cooling system of the target is also included in the calculations. Calculations are performed using the MCNP code. After the optimization of our beam-shaper a study of the dose distribution in the head had been made. The therapeutic gain is increased in 9% while the current required for one hour treatment is decreased in comparison with the trading prototypes of NG used for BNCT. (Author)

  13. External beam monitoring of the Cyclone 30 cyclotron of IPEN-CNEN-SP

    International Nuclear Information System (INIS)

    Matsuda, Hylton

    2002-01-01

    Due to the increasing demand for cyclotron radioisotopes and the high cost of equipment and materials involved in the process, it becomes evident the importance of external beam monitoring of the cyclotron. In this way, the beam of the Cyclone 30 cyclotron of IPEN-CNEN/S P was characterized throughout the evaluation of its current intensity, profile (position, focus and geometry), alignment and homogeneity, by measuring currents, temperatures and pressures of irradiation systems. For this purpose, techniques and conventional devices, thermocouples and pressure sensors associated to electronic of instrumentation, and technology and flexibility of micro controllers allowed observing the beam behavior during irradiations in real time. The ion beam energy was also evaluated using activation analysis technique of monitor reactions in nat Cu. The beam monitoring systems have been contributing to prevent material damages and they have already been used in routine irradiations, bringing important advantages in the process of beam optimization of the Cyclone 30. (author)

  14. The usage of electron beam to produce radio isotopes through the uranium fission by γ-rays and neutrons

    International Nuclear Information System (INIS)

    Bunatyan, G.G.; Nikolenko, V.G.; Popov, A.V.

    2010-01-01

    We treat the production of desirable radio isotopes due to the 238 U photo-fission by the bremsstrahlung induced in converter by an initial electron beam provided by a linear electron accelerator. We consider as well the radio isotope production through the 238 U fission by the neutrons that stem in the 238 U sample irradiated by that bremsstrahlung. The yield of the most applicable radio isotope 99 Mo is calculated. We correlate the findings acquired in the work presented with those obtained by treating the nuclear photo-neutron reaction. Menace of the plutonium contamination of an irradiated uranium sample because of the neutron capture by 238 U is considered. As we get convinced, the photo-neutron production of radio isotopes proves to be more practicable than the production by the uranium photo- and neutron-fission. Both methods are certain to be brought into action due to usage of the electron beam provided by modern linear accelerators

  15. Problems and prospects of neutron imaging

    International Nuclear Information System (INIS)

    Kobayashi, Hisao

    2008-01-01

    Technical problems and future prospects of neutron imaging and neutron radiography are reviewed and discussed for further development. For technical problems, neutron sources together with cold neutron, ultra-cold neutron, epithermal and fast-neutron beams, energy converters, and the intensity of neutron beam, dynamic range associated with imaging procedure, etc, are reviewed. As standardization, such indicators as beam purity, sensitivity, image quality, and beam quality are discussed and limitation of neutron radiography is also presented. As neutron imaging has developed as a nondestructive testing technique in industrial applications, further problems and prospects of quality control and qualification to perform neutron radiography, standardization and international cooperation of neutron imaging are discussed. (S. Ohno)

  16. Measurement of stray neutron doses inside the treatment room from a proton pencil beam scanning system

    Czech Academy of Sciences Publication Activity Database

    Mojzeszek, N.; Farah, J.; Klodowska, M.; Ploc, Ondřej; Stolarczyk, L.; Waligorski, M. P. R.; Olko, P.

    2017-01-01

    Roč. 34, č. 2 (2017), s. 80-84 ISSN 1120-1797 Institutional support: RVO:61389005 Keywords : secondary neutrons * proton therapy * pencil beam scanning systtems * out-of-field doses * stray neutron doses * TEPC Subject RIV: FP - Other Medical Disciplines OBOR OECD: Radiology, nuclear medicine and medical imaging Impact factor: 1.990, year: 2016

  17. A prospect for the development of an epithermal neutron beam from the horizontal channel at the TRNC for brain tumors treatment based on the BNCT method

    International Nuclear Information System (INIS)

    Ben-Ghazail, Mustafa Ali

    2005-01-01

    In this work the epithermal neutron was development from horizontal channel VI at Tajoura research reactor which can be used for Boron Neutron Capture Therapy. The analysis of reactivity and control rod worth is performed by three dimensional continues energy MCNP-4C code with neutron cross section data from the ENDF/B-VI evaluation. The neutron beam which is developed for medical purpose is generated from the reactor core by means of U-235 fission. The neutrons leaking through the cavity of HC in Be-9 reflector is guided through a tube made of stainless steel to patient position. The HC has two wheels. The first wheel is small and is used as a gate. The second is large and have three positions one to close the gate, the second to open the gate while the third for loading collimator. The collimator consists of the moderators and filters to optimize the neutron beam which is installed in the loading position. The HC VI is extended to the room constructed to allow space for other horizontal channels users. materials are used to optimize the neutron beam which was selected depending on neutron beam properties related to core loading and control rod position. The results of the development study show that the required values for the neutron beam characteristic can be nearly reached. The different comparisons of the calculations performed using MCNP-4C code with the requirements values of characteristics neutron beam show that the result values of MCNP-4C code model are reliable. (author)

  18. Elemental analysis of artefacts - establishing external beam PIXE

    International Nuclear Information System (INIS)

    Alves, A.; Johnston, P.; Short, R.; Bubb, I.

    1999-01-01

    The development of an external PIXE facility on the 1 MV Tandetron accelerator at RMIT has led to a wide range of research possibilities. A proton beam, generated inside a vacuum is brought into air via an Au coated Kapton foil exit window (thickness 8μm, diameter 0.35mm). Monitoring of the beam intensity is achieved by detecting backscattered protons from the inside Au coating on the window. Artefacts, which may be too large to be placed inside the vacuum, are positioned in the beamline opposite the exit window. An optical system consisting of a CCD camera, alignment laser and two mirrors allows viewing of a region of the target 10mm x 10mm. This technique provides quantitative analysis of elements in the pigments used in paintings and on ceramics, which is a valuable tool in art conservation and authentication. Application of the technique to a ceramic sample from the historic house 'Viewbank' is described

  19. Radiotherapy in poor risk patients with stage I cancer of the endometrium: results of not giving external beam radiotherapy.

    Science.gov (United States)

    DeCruze, B; Guthrie, D

    1999-01-01

    Poor prognosis (poorly differentiated and/or deep myometrial invasion) Stage I endometrial cancer can have a relapse rate as high as 50%. Traditionally, most clinical oncologists treat these patients with external beam radiotherapy after surgery but there is no evidence to show that this improves survival. The retrospective study looks at the results of not giving external beam radiotherapy in 25 consecutive patients and compares the results with a group of 13 consecutive patients who did have such treatment. The two groups were comparable with regard to age, degree of differentiation and degree of invasion. Survival was comparable in the two groups. There is no evidence of any obvious decrease in survival from withholding external beam radiotherapy, but this was not a prospective randomized controlled trial. This study illustrates that it is essential that the Medical Research Council ASTEC trial should be supported because this will determine the true place of external beam radiotherapy in such patients.

  20. Simulation study of the photon quality correction factors of ionization chambers for FiR 1 epithermal neutron beam

    International Nuclear Information System (INIS)

    Koivunoro, H.; Uusi-Simola, J.; Savolainen, S.; Kotiluoto, P.; Auterinen, I.; Kosunen, A.

    2006-01-01

    At FiR 1 BNCT facility in Finland, neutron-insensitive Mg(Ar) ionization chambers are used for photon dose measurements in an epithermal neutron beam. Previously, photon sensitivity factors for the chamber for the measurements in a water phantom in FiR 1 beam have been determined experimentally from measurements in 60 Co gamma and in a 6 MV clinical accelerator photon beams. However, the response of the ionization chamber in a water phantom depends on energy spectrum and angle of the photons and the secondary electrons created inside the phantom and may differ depending on type of the irradiation source (accelerator vs. an epithermal neutron beam). Also, the experimental sensitivity factor does not take into account the possible perturbations in the photon production in phantom caused by the ionization chamber materials. Therefore, it is necessary to determine the photon quality correction factors (k Qγ ) for the Mg(Ar) chamber at the FiR 1 beam through computer simulations. In this study, the k Qγ factors have been determined for Mg(Ar) chamber from Monte Carlo calculations of absorbed photon dose at two depths in a water phantom using MCNP code. The k qγ factors obtained with this method are compared to the sensitivity factors determined with measurements in an accelerator photon beam and to the k Qγ factors published previously. (author)

  1. Development of an external beam nuclear microprobe on the Aglae facility of the Louvre museum

    Energy Technology Data Exchange (ETDEWEB)

    Calligaro, T.; Dran, J.-C. E-mail: dran@culture.fr; Ioannidou, E.; Moignard, B.; Pichon, L.; Salomon, J

    2000-03-01

    The external beam line of our facility has been recently equipped with the focusing system previously mounted on a classical nuclear microprobe. When using a 0.1 {mu}m thick Si{sub 3}N{sub 4} foil for the exit window and flowing helium on the sample under analysis, a beam spot as small as 10 {mu}m is attainable at a distance of 3 mm from the window. Elemental micromapping is performed by mechanical scanning. An electronic device has been designed which allows XY scanning by moving the sample under the beam by steps down to 0.1 {mu}m. Beam monitoring is carried out by means of the weak X-ray signal emitted by the exit foil and detected by a specially designed Si(Li) detector cooled by Peltier effect. The characteristics of external beams of protons and alpha particles are evaluated by means of resonance scanning and elemental mapping of a grid. An example of application is presented, dealing with elemental micro-mapping of inclusions in gemstones.

  2. High-power electron beam tests of a liquid-lithium target and characterization study of (7)Li(p,n) near-threshold neutrons for accelerator-based boron neutron capture therapy.

    Science.gov (United States)

    Halfon, S; Paul, M; Arenshtam, A; Berkovits, D; Cohen, D; Eliyahu, I; Kijel, D; Mardor, I; Silverman, I

    2014-06-01

    A compact Liquid-Lithium Target (LiLiT) was built and tested with a high-power electron gun at Soreq Nuclear Research Center (SNRC). The target is intended to demonstrate liquid-lithium target capabilities to constitute an accelerator-based intense neutron source for Boron Neutron Capture Therapy (BNCT) in hospitals. The lithium target will produce neutrons through the (7)Li(p,n)(7)Be reaction and it will overcome the major problem of removing the thermal power >5kW generated by high-intensity proton beams, necessary for sufficient therapeutic neutron flux. In preliminary experiments liquid lithium was flown through the target loop and generated a stable jet on the concave supporting wall. Electron beam irradiation demonstrated that the liquid-lithium target can dissipate electron power densities of more than 4kW/cm(2) and volumetric power density around 2MW/cm(3) at a lithium flow of ~4m/s, while maintaining stable temperature and vacuum conditions. These power densities correspond to a narrow (σ=~2mm) 1.91MeV, 3mA proton beam. A high-intensity proton beam irradiation (1.91-2.5MeV, 2mA) is being commissioned at the SARAF (Soreq Applied Research Accelerator Facility) superconducting linear accelerator. In order to determine the conditions of LiLiT proton irradiation for BNCT and to tailor the neutron energy spectrum, a characterization of near threshold (~1.91MeV) (7)Li(p,n) neutrons is in progress based on Monte-Carlo (MCNP and Geant4) simulation and on low-intensity experiments with solid LiF targets. In-phantom dosimetry measurements are performed using special designed dosimeters based on CR-39 track detectors. © 2013 Elsevier Ltd. All rights reserved.

  3. Measuring the Density of Different Materials by Using the Collimated Fast Neutron Beam

    Energy Technology Data Exchange (ETDEWEB)

    Sudac, D.; Nad, K.; Orlic, Z.; Obhodas, J. [Rudjer Boskovic Institute, Bijenicka c. 54, 10000 Zagreb (Croatia); Valkovic, V. [Rudjer Boskovic Institute, Zagreb (Croatia); Kvinticka 62, Zagreb (Croatia)

    2015-07-01

    It was demonstrated in the previous work that various threat materials could be detected inside the sea going cargo container by measuring the three variables, carbon and oxygen concentration and density of investigated material. Density was determined by measuring transmitted neutrons, which is not always practical in terms of setting up the instrument geometry. In order to enable more geometry flexibility, we have investigated the possibility of using the scattered neutrons in cargo material identification. For that purpose, the densities of different materials were measured depending on the position of neutron detectors and neutron generator with respect to the target position. One neutron detector was put above the target, one behind and one in front of the target, above the neutron generator. It was shown that all three positions of neutron detectors can be successfully used to measure the target density, but only if the detected neutrons are successfully discriminated from the gamma rays. Although the associated alpha particle technique/associate particle imaging (API) was used to discriminate the neutrons from the gamma rays, it is believed that the same results would be obtained by using the pulse shape discrimination method. In that way API technique can be avoided and the neutron generator which produces much higher beam intensity than 10{sup 8} n/s can be used. (authors)

  4. Design and optimization of a beam shaping assembly for BNCT based on D-T neutron generator and dose evaluation using a simulated head phantom.

    Science.gov (United States)

    Rasouli, Fatemeh S; Masoudi, S Farhad

    2012-12-01

    A feasibility study was conducted to design a beam shaping assembly for BNCT based on D-T neutron generator. The optimization of this configuration has been realized in different steps. This proposed system consists of metallic uranium as neutron multiplier, TiF(3) and Al(2)O(3) as moderators, Pb as reflector, Ni as shield and Li-Poly as collimator to guide neutrons toward the patient position. The in-air parameters recommended by IAEA were assessed for this proposed configuration without using any filters which enables us to have a high epithermal neutron flux at the beam port. Also a simulated Snyder head phantom was used to evaluate dose profiles due to the irradiation of designed beam. The dose evaluation results and depth-dose curves show that the neutron beam designed in this work is effective for deep-seated brain tumor treatments even with D-T neutron generator with a neutron yield of 2.4×10(12) n/s. The Monte Carlo Code MCNP-4C is used in order to perform these calculations. Copyright © 2012 Elsevier Ltd. All rights reserved.

  5. External beam radiation therapy for prostate cancer

    International Nuclear Information System (INIS)

    Forman, Jeffrey D.

    1996-01-01

    Purpose/Objectives: The intent of this course is to review the issues involved in the management of non-metastatic adenocarcinoma of the prostate. -- The value of pre-treatment prognostic factors including stage, grade and PSA value will be presented, and their value in determining therapeutic strategies will be discussed. -- Controversies involving the simulation process and treatment design will be presented. The value of CT scanning, Beams-Eye View, 3-D planning, intravesicle, intraurethral and rectal contrast will be presented. The significance of prostate and patient movement and strategies for dealing with them will be presented. -- The management of low stage, low to intermediate grade prostate cancer will be discussed. The dose, volume and timing of irradiation will be discussed as will the role of neo-adjuvant hormonal therapy, neutron irradiation and brachytherapy. The current status of radical prostatectomy and cryotherapy will be summarized. Treatment of locally advanced, poorly differentiated prostate cancer will be presented including a discussion of neo-adjuvant and adjuvant hormones, dose-escalation and neutron irradiation. -- Strategies for post-radiation failures will be presented including data on cryotherapy, salvage prostatectomy and hormonal therapy (immediate, delayed and/or intermittent). New areas for investigation will be reviewed. -- The management of patients post prostatectomy will be reviewed. Data on adjuvant radiation and therapeutic radiation for biochemical or clinically relapsed patients will be presented. This course hopes to present a realistic and pragmatic overview for treating patients with non-metastatic prostatic cancer

  6. LANSCE Beam Current Limiter (XL)

    International Nuclear Information System (INIS)

    Gallegos, F.R.; Hall, M.J.

    1997-01-01

    The Radiation Security System (RSS) at the Los Alamos Neutron Science Center (LANSCE) is an engineered safety system that provides personnel protection from prompt radiation due to accelerated proton beams. The Beam Current Limiter (XL), as an active component of the RSS, limits the maximum average current in a beamline, thus the current available for a beam spill accident. Exceeding the pre-set limit initiates action by the RSS to mitigate the hazard (insertion of beam stoppers in the low energy beam transport). The beam limiter is an electrically isolated, toroidal transformer and associated electronics. The device was designed to continuously monitor beamline currents independent of any external timing. Fail-safe operation was a prime consideration in its development. Fail-safe operation is defined as functioning as intended (due to redundant circuitry), functioning with a more sensitive fault threshold, or generating a fault condition. This report describes the design philosophy, hardware, implementation, operation, and limitations of the device

  7. Target volume delineation in external beam partial breast irradiation: Less inter-observer variation with preoperative- compared to postoperative delineation

    International Nuclear Information System (INIS)

    Leij, Femke van der; Elkhuizen, Paula H.M.; Janssen, Tomas M.; Poortmans, Philip; Sangen, Maurice van der; Scholten, Astrid N.; Vliet-Vroegindeweij, Corine van; Boersma, Liesbeth J.

    2014-01-01

    The challenge of adequate target volume definition in external beam partial breast irradiation (PBI) could be overcome with preoperative irradiation, due to less inter-observer variation. We compared the target volume delineation for external beam PBI on preoperative versus postoperative CT scans of twenty-four breast cancer patients

  8. Average fast neutron flux in three energy ranges in the Quinta assembly irradiated by two types of beams

    Directory of Open Access Journals (Sweden)

    Strugalska-Gola Elzbieta

    2017-01-01

    Full Text Available This work was performed within the international project “Energy plus Transmutation of Radioactive Wastes” (E&T - RAW for investigations of energy production and transmutation of radioactive waste of the nuclear power industry. 89Y (Yttrium 89 samples were located in the Quinta assembly in order to measure an average high neutron flux density in three different energy ranges using deuteron and proton beams from Dubna accelerators. Our analysis showed that the neutron density flux for the neutron energy range 20.8 - 32.7 MeV is higher than for the neutron energy range 11.5 - 20.8 MeV both for protons with an energy of 0.66 GeV and deuterons with an energy of 2 GeV, while for deuteron beams of 4 and 6 GeV we did not observe this.

  9. A verification scenario of nuclear plus interference scattering effects using neutron incident angle distribution to the wall in beam-injected deuterium plasmas

    International Nuclear Information System (INIS)

    Sugiyama, Shota; Matsuura, Hideaki; Uchiyama, Daisuke; Sawada, Daisuke; Watanabe, Tsuguhiro; Goto, Takuya; Mitarai, Osamu

    2015-01-01

    A verification scenario of knock-on tail formation in the deuteron distribution function due to nuclear plus interference scattering is presented by observing the incident angle distribution of neutrons in a vacuum vessel. Assuming a knock-on tail created in a "3He-beam-injected deuterium plasma, the incident angle distribution and energy spectra of the neutrons produced by fusion reactions between 1-MeV and thermal deuterons are evaluated. The relation between the neutron incident angle to the vacuum vessel and neutron energy is examined in the case of anisotropic neutron emission due to knock-on tail formation in neutral-beam-injected plasmas. (author)

  10. In-beam γ-ray spectroscopy of the neutron rich 39Si

    International Nuclear Information System (INIS)

    Sohler, D.; Dombradi, Zs.; Achouri, N.L.; Angelique, J.C.; Bastin, B.; Azaiez, F.; Baiborodin, D.; Borcea, R.

    2009-01-01

    Complete text of publication follows. In order to clarify the role of proton excitations across the Z = 14 subshell closure in neutron-rich Si isotopes, we investigated the structure of the 14 39 Si 25 isotope, having three neutron-hole configurations with respect to an N = 28 core. The excited states of 39 Si were studied by in-beam γ-ray spectroscopy trough fragmentation of radioactive beams. The experiment was performed at the GANIL facility in France. The radioactive beams were produced by the fragmentation of the stable 48 Ca beam of 60 MeV/u energy and 4μA intensity on a 12 C target in the SISSI device. The cocktail beam produced was impinged onto a 9 Be target. The nuclei produced in the secondary fragmentation reaction were selected and unambiguously identified by the SPEG spectrometer. In the performed experiment the 39 Si nuclei were obtained via 1p, 1p1n, 2p1n and 2p2n knockout reactions from the 40,41 P and 42,43 S secondary beams. To measure the γ rays emitted from the excited states, the secondary target was surrounded by the 4π 'Chateau de Crystal' array consisting of 74 BaF 2 scintillators. The γ-ray spectra were generated by gating event-by-event on the incoming secondary beam particles and the ejectiles after the secondary target. For the γ rays emitted by the fast moving fragments accurate Doppler correction was performed. From the obtained γ spectra of 39 Si displayed in Figure 1, two strong γ transitions at 163 and 397 keV as well as weaker ones at 303, 657, 906, 1143 and 1551 keV have been identified. γγ coincidences were obtained in 39 Si after having added all data from the various reaction channels giving rise to 39 Si. Analysing these data the 163 keV transition was found to be in coincidence with the 657, 1143 and 1551 keV ones, but not with the 397 keV transition. The two lines of the 303+397 keV doublet are in mutual coincidence, and one or both of them are found in coincidence with the 906 keV transition.

  11. Distortion of optical feedback signals in microchip Nd:YAG lasers subjected to external multi-beam interference feedback

    International Nuclear Information System (INIS)

    Yi-Dong, Tan; Shu-Lian, Zhang; Zhou, Ren; Cheng, Ren; Yi-Nan, Zhang

    2010-01-01

    This paper proposes a theoretical analysis for the characteristics of an external cavity Nd:YAG laser with feedback of multiple-beam interference, which is induced by the multi-reentrance of the light from the external Fabry–Perot cavity. The theoretical model considers the multiple beam interference of the external Fabry–Perot cavity. It is found that the optical feedback signals are distorted to pulse waveforms instead of the sinusoidal ones in conventional feedback. The experimental results are in good agreement with the theoretical analysis. The obtained theoretical and experimental results can advance the development of a laser feedback interferometer

  12. Cobalt-60 Machines and Medical Linear Accelerators: Competing Technologies for External Beam Radiotherapy.

    Science.gov (United States)

    Healy, B J; van der Merwe, D; Christaki, K E; Meghzifene, A

    2017-02-01

    Medical linear accelerators (linacs) and cobalt-60 machines are both mature technologies for external beam radiotherapy. A comparison is made between these two technologies in terms of infrastructure and maintenance, dosimetry, shielding requirements, staffing, costs, security, patient throughput and clinical use. Infrastructure and maintenance are more demanding for linacs due to the complex electric componentry. In dosimetry, a higher beam energy, modulated dose rate and smaller focal spot size mean that it is easier to create an optimised treatment with a linac for conformal dose coverage of the tumour while sparing healthy organs at risk. In shielding, the requirements for a concrete bunker are similar for cobalt-60 machines and linacs but extra shielding and protection from neutrons are required for linacs. Staffing levels can be higher for linacs and more staff training is required for linacs. Life cycle costs are higher for linacs, especially multi-energy linacs. Security is more complex for cobalt-60 machines because of the high activity radioactive source. Patient throughput can be affected by source decay for cobalt-60 machines but poor maintenance and breakdowns can severely affect patient throughput for linacs. In clinical use, more complex treatment techniques are easier to achieve with linacs, and the availability of electron beams on high-energy linacs can be useful for certain treatments. In summary, there is no simple answer to the question of the choice of either cobalt-60 machines or linacs for radiotherapy in low- and middle-income countries. In fact a radiotherapy department with a combination of technologies, including orthovoltage X-ray units, may be an option. Local needs, conditions and resources will have to be factored into any decision on technology taking into account the characteristics of both forms of teletherapy, with the primary goal being the sustainability of the radiotherapy service over the useful lifetime of the equipment

  13. A retrospective study of external beam radiation, neutron brachytherapy, and concurrent chemotherapy for patients with localized advanced carcinoma of the esophagus

    International Nuclear Information System (INIS)

    Ma, Kai; Wang, Qifeng; Li, Tao; Liu, Huiming; Liu, Bo; Jia, Xitang; Li, Shufeng; Lang, Junyuan; Zhang, Mingzhi

    2014-01-01

    The aim of this study was to retrospectively observe and analyze the long-term treatment outcomes of a total of 140 esophageal cancer patients who were treated with californium-252 ( 252 Cf) neutron brachytherapy (NBT) in combination with external beam radiotherapy (EBRT) and concurrent chemotherapy (CCT). From January 2002 to November 2012, 140 patients with esophageal cancer underwent NBT in combination with EBRT and CCT. The distribution of the patient numbers over the various cancer stages of IIA, IIB, and III were 43, 7, and 90, respectively. The total radiation dose to the reference point via NBT was 8–25 Gy-eq in two to five fractions with one fraction per week. The total dose via EBRT was 50–60 Gy, which was delivered over a period of five to six weeks with normal fractionation. Fifty-four and 86 patients received tegafur suppositories (TS) and continuous infusion of fluorouracil (5-Fu) with cisplatin (CDDP), respectively. The median follow-up time was 42 months. The minimum follow-up was three months, and the maximum was 106 months. The overall median survival including death from all causes was 29.5 months. The five-year overall survival rate (OS) and local control (LC) were 33.4% and 55.9%, respectively. The chemotherapy regimen was a factor that was significantly associated with OS (p = 0.025) according to univariate analysis. The five-year OSs were 27.4% and 44.3% for the PF and TS chemotherapy regimens, respectively. Regarding acute toxicity, no incidences of fistula or massive bleeding were observed during this treatment period. The incidence of severe, late complications was related to the PF chemotherapy regimen (p = 0.080). The clinical data indicated that NBT in combination with EBRT and CRT produced favorable local control and long-term survival rates for patients with esophageal cancer and that the side effects were tolerable. A reasonable CRT regimen can decrease the rate of severe, late complications

  14. Physical and microdosimetric studies of neutron beams used in radiobiology

    International Nuclear Information System (INIS)

    Lavigne, Bernard.

    1978-10-01

    Microdosimetry is concerned with the energy imparted in microscopic regions irradiated with different radiations. The energy imparted is subject to random fluctuations. The probability distribution may be estimated by measurements or by computing code. The results obtained with a tissue-equivalent proportional counter of Rossi type are compared with those obtained by means of the computer code of DENNIS and EDWARDS. Beams of monoenergetic neutrons of 0.68 MeV, 2.18 MeV, 3.53 MeV, 5.5 MeV and 14.18 MeV, and fission neutrons were used. The computer code requires that neutron spectrum and W, the mean energy expanded in a gas per ion pair formed are determined. The first part of the report thus describes: -spectrometric measurements done with a NE 213 scintillator; -W measurements with a chamber operating alternately as ionization chamber and proportional counter. Results are given for H + , He + , C + , N + and O + ions in argon and tissue-equivalent gas in the energy range 25 keV - 500 keV [fr

  15. Instrumentation with polarized neutrons

    International Nuclear Information System (INIS)

    Boeni, P.; Muenzer, W.; Ostermann, A.

    2009-01-01

    Neutron scattering with polarization analysis is an indispensable tool for the investigation of novel materials exhibiting electronic, magnetic, and orbital degrees of freedom. In addition, polarized neutrons are necessary for neutron spin precession techniques that path the way to obtain extremely high resolution in space and time. Last but not least, polarized neutrons are being used for fundamental studies as well as very recently for neutron imaging. Many years ago, neutron beam lines were simply adapted for polarized beam applications by adding polarizing elements leading usually to unacceptable losses in neutron intensity. Recently, an increasing number of beam lines are designed such that an optimum use of polarized neutrons is facilitated. In addition, marked progress has been obtained in the technology of 3 He polarizers and the reflectivity of large-m supermirrors. Therefore, if properly designed, only factors of approximately 2-3 in neutron intensity are lost. It is shown that S-benders provide neutron beams with an almost wavelength independent polarization. Using twin cavities, polarized beams with a homogeneous phase space and P>0.99 can be produced without significantly sacrificing intensity. It is argued that elliptic guides, which are coated with large m polarizing supermirrors, provide the highest flux.

  16. External Beam Radiotherapy for Carcinoma of the Extrahepatic Biliary System

    International Nuclear Information System (INIS)

    Chun, Ha Chung; Lee, Myung Za

    1996-01-01

    Purpose : To evaluate the effectiveness and tolerance of patients of external beam radiotherapy of carcinoma of the extrahepatic biliary system (EHBS) including gall bladder (GB) and extrahepatic bile ducts (EHBD) and to define the role of radiotherapy for these tumors. Methods and Materials : We retrospectively analyzed the records of 43 patients with carcinoma of the EHBS treated with external beam radiotherapy at our institution between April, 1986 and July, 1994. Twenty three patients had GB cancers and remaining 20 patients did EHBD cancers. Of those 23 GB cancers, 2 had Stage II, 12 did Stage III and 9 did Stage IV disease, respectively. Male to female ratio was 11 to 12. Fifteen patients underwent radical surgery with curative intent and 8 patients did biopsy and bypass surgery alone. Postoperatively 16 patients were irradiated with 4500 cGy or higher doses and 4 patients with 3180 to 4140 cGy. Follow up periods ranged from 8 to 34 months. Results : overall median survival time of patients with GB cancer was 11 months. Median survival time for patients with Stage III and IV disease were 14 months and 5 months, respectively. Corresponding two year survival rates were 36%(4/11) and 13%(1/8), respectively. Those who underwent surgery with curative intent showed significantly better survival at 12 months than those who underwent bypass surgery alone(67% vs 13%). None of the patients died of treatment related complications. Median survival time for entire group of 20 EHBD patients was 10 months. Median survivals of 10 Stage III and 7 Stage IV disease were 10 and 8 months, respectively. Two patients who underwent Whipple's procedure had 11 and 14 month survival and those treated with resection and drainage showed median survival of 10 month. Conclusion : Postoperative external beam radiotherapy for carcinoma of the extrahepatic billary system is well tolerated and might improve survival of patients. especially those with respectable lesions with microscopic or

  17. Theoretical study on production of heavy neutron-rich isotopes around the N=126 shell closure in radioactive beam induced transfer reactions

    Directory of Open Access Journals (Sweden)

    Long Zhu

    2017-04-01

    Full Text Available In order to produce more unknown neutron-rich nuclei around N=126, the transfer reactions 136Xe + 198Pt, 136–144Xe + 208Pb, and 132Sn + 208Pb are investigated within the framework of the dinuclear system (DNS model. The influence of neutron excess of projectile on production cross sections of target-like products is studied through the reactions 136,144Xe + 208Pb. We find that the radioactive projectile 144Xe with much larger neutron excess is favorable to produce neutron-rich nuclei with charge number less than the target rather than produce transtarget nuclei. The incident energy dependence of yield distributions of fragments in the reaction 132Sn + 208Pb are also studied. The production cross sections of neutron-rich nuclei with Z=72–77 are predicted in the reactions 136–144Xe + 208Pb and 132Sn + 208Pb. It is noticed that the production cross sections of unknown neutron-rich nuclei in the reaction 144Xe + 208Pb are at least two orders of magnitude larger than those in the reaction 136Xe + 208Pb. The radioactive beam induced transfer reactions 139,144Xe + 208Pb, considering beam intensities proposed in SPIRAL2 (Production System of Radioactive Ion and Acceleration On-Line project as well, for production of neutron-rich nuclei around the N=126 shell closure are investigated for the first time. It is found that, in comparison to the stable beam 136Xe, the radioactive beam 144Xe shows great advantages for producing neutron-rich nuclei with N=126 and the advantages get more obvious for producing nuclei with less charge number.

  18. Radiation dosimetry at the BNL High Flux Beam Reactor

    International Nuclear Information System (INIS)

    Holden, N.E.; Hu, J.P.; Reciniello, R.N.

    1998-02-01

    The HFBR is a heavy water, D 2 O, cooled and moderated reactor with twenty-eight fuel elements containing a maximum of 9.8 kilograms of 235 U. The core is 53 cm high and 48 cm in diameter and has an active volume of 97 liters. The HFBR, which was designed to operate at forty mega-watts, 40 NW, was upgraded to operate at 60 NW. Since 1991, it has operated at 30 MW. In a normal 30 MW operating cycle the HFBR operates 24 hours a day for thirty days, with a six to fourteen day shutdown period for refueling and maintenance work. While most reactors attempts to minimize the escape of neutrons from the core, the HFBR's D 2 O design allows the thermal neutron flux to peak in the reflector region and maximizes the number of thermal neutrons available to nine horizontal external beams, H-1 to H-9. The HFBR neutron dosimetry effort described here compares measured and calculated energy dependent neutron and gamma ray flux densities and/or dose rates at horizontal beam lines and vertical irradiation thimbles

  19. Flexural behaviour of RCC beams with externally bonded FRP

    Science.gov (United States)

    Vignesh, S. Arun; Sumathi, A.; Saravana Raja Mohan, K.

    2017-07-01

    The increasing use of carbon and glass fibre reinforced polymer (FRP) sheets for strengthening existing reinforced concrete beams has generated considerable interest in understanding the behavior of the FRP sheets when subjected to bending. The study on flexure includes various parameters like percentage of increase in strength of the member due to the externally bonded Fiber reinforced polymer, examining the crack patterns, reasons of debonding of the fibre from the structure, scaling, convenience of using the fibres, cost effectiveness etc. The present work aims to study experimentally about the reasons behind the failure due to flexure of an EB-FRP concrete beam by studying the various parameters. Deflection control may become as important as flexural strength for the design of FRPreinforced concrete structures. A numerical model is created using FEM software and the results are compared with that of the experiment.

  20. Beam dynamics simulation of the Spallation Neutron Source linear accelerator

    International Nuclear Information System (INIS)

    Takeda, H.; Billen, J.H.; Bhatia, T.S.

    1998-01-01

    The accelerating structure for Spallation Neutron Source (SNS) consists of a radio-frequency-quadrupole-linac (RFQ), a drift-tube-linac (DTL), a coupled-cavity-drift-tube-linac (CCDTL), and a coupled-cavity-linac (CCL). The linac is operated at room temperature. The authors discuss the detailed design of linac which accelerates an H - pulsed beam coming out from RFQ at 2.5 MeV to 1000 MeV. They show a detailed transition from 402.5 MHz DTL with a 4 βλ structure to a CCDTL operated at 805 MHz with a 12 βλ structure. After a discussion of overall feature of the linac, they present an end-to-end particle simulation using the new version of the PARMILA code for a beam starting from the RFQ entrance through the rest of the linac. At 1000 MeV, the beam is transported to a storage ring. The storage ring requires a large (±500-keV) energy spread. This is accomplished by operating the rf-phase in the last section of the linac so the particles are at the unstable fixed point of the separatrix. They present zero-current phase advance, beam size, and beam emittance along the entire linac

  1. PRR1 rehabilitation and the current and future neutron beam utilization program

    International Nuclear Information System (INIS)

    Calix, Virginia S.

    2003-01-01

    The PRR1 research reactor is the center for nuclear science R and D in the Philippines. It is located in Metro Manila inside the campus of the University of the Philippines. It is a General Electric designed reactor and was commissioned in 1963 with a rated thermal power of 1 MW. It was operated for 20 years enabling the Institute to pursue activities in radioisotope production, neutron scattering, activation analyses and other R and D activities requiring neutron beams. In 1984 it was converted to a 3 MW TRIGA Type reactor. Conversion was completed and test run was successfully accomplished in 1988. In the same year the reactor was shut down due to a leak in the aluminum linear of the reactor pool. During the repair deterioration of the other parts of the reactor was discovered that could affect the safety of its operation. A rehabilitation program is made that include the reactor core box and all the other peripherals that could affect its safety operation and to address present regulatory concerns. Modification of the core box and its position in the pool opens opportunities and possibilities to suit specific neutron beam application for the users. Plans for this will be presented as well as the strategy of the Institute to satisfy the current need for reactor based facilities to enhanced implementation of the Country's S and T Program. (author)

  2. Dependence of neutron rate production with accelerator beam profile and energy range in an ADS-TRIGA RC1 reactor

    Energy Technology Data Exchange (ETDEWEB)

    Firoozabadi, M.M.; Karimi, J. [Birjand Univ. (Iran, Islamic Republic of). Dept. of Physics; Zangian, M. [Shahid Beheshti Univ., Tehran (Iran, Islamic Republic of). Nuclear Engineering Dept.

    2016-12-15

    Lead, mercury, tantalum and tungsten were used as target material for calculation of spallation processes in an ADS-TRIGA RC1 reactor. The results show that tungsten has the highest neutron production rate. Therefore it was selected as target material for further calculations. The sensitivity of neutron parameters of the ADS reactor core relative to a change of beam profile and proton energy was determined. The core assembly and parameters of the TRIGA RC1 demonstration facility were used for the calculation model. By changing the proton energy from 115 to 1 400 MeV by using the intra-nuclear cascade model of Bertini (INC-Bertini), the quantity of the relative difference in % for energy gain (G) and spallation neutron yield (Y{sub n/p}), increases to 289.99 % and 5199.15 % respectively. These changes also reduce the amount of relative difference for the proton beam current (I{sub p}) and accelerator power (P{sub acc}), 99.81 % and 81.28 % respectively. In addition, the use of a Gaussian distribution instead of a uniform distribution in the accelerator beam profile increases the quantity of relative difference for energy gain (G), net neutron multiplication (M) and spallation neutron yield (Y{sub n/p}), up to 4.93 %, 4.9 % and 5.55 % respectively.

  3. Structural design study of a proton beam window for a 1-MW spallation neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Teraoku, Takuji; Terada, Atsuhiko; Maekawa, Fujio; Meigo, Shin-ichiro; Kaminaga, Masanori; Ishikura, Syuichi; Hino, Ryutaro [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2003-03-01

    A 1-MW spallation neutron source aiming at materials and life science researches will be constructed under the JAERI-KEK High-intensity Proton Accelerator Project (J-PARC). A proton beam passes through a proton beam window, and be injected into a target of the neutron source. The proton beam window functions as a boundary wall between a high vacuum area in the proton beam line and a helium atmosphere at about atmospheric pressure in a helium vessel which contains the target and moderators. The proton beam window is cooled by light water because high heat-density is generated in the window material by interactions with the proton beam. Then, uniformity of the water flow is requested at the window to suppress a hot-spot that causes excessive thermal stress and cooling water boiling. Also, the window has to be strong enough in its structure for inner stress due to water pressure and thermal stress due to heat generation. In this report, we propose two types of proton beam windows; one flat-type that is easy to manufacture, and the other, curved-type that has high stress resistivity. As a part of design study for the windows, evaluation of strength of structure and thermal hydraulic analysis were conducted. As a result, it was found that sufficient heat removal was assured with uniform water flow at the window, and stress caused by internal water pressure and thermal stress could be maintained below allowable stress values. Accordingly, it was confirmed that the proton beam window designs were feasible. (author)

  4. Beam dynamics study of a 30 MeV electron linear accelerator to drive a neutron source

    Science.gov (United States)

    Kumar, Sandeep; Yang, Haeryong; Kang, Heung-Sik

    2014-02-01

    An experimental neutron facility based on 32 MeV/18.47 kW electron linac has been studied by means of PARMELA simulation code. Beam dynamics study for a traveling wave constant gradient electron accelerator is carried out to reach the preferential operation parameters (E = 30 MeV, P = 18 kW, dE/E E-gun, pre-buncher, buncher, and 2 accelerating columns. A disk-loaded, on-axis-coupled, 2π/3-mode type accelerating rf cavity is considered for this linac. After numerous optimizations of linac parameters, 32 MeV beam energy is obtained at the end of the linac. As high electron energy is required to produce acceptable neutron flux. The final neutron flux is estimated to be 5 × 1011 n/cm2/s/mA. Future development will be the real design of a 30 MeV electron linac based on S band traveling wave.

  5. A pulsed neutron monochromatic beam at the ET-RR-1 reactor

    International Nuclear Information System (INIS)

    Adib, M.; Abdel-Kawy, A.; Eid, Y.; Maayouf, R.M.A.

    1985-01-01

    A pulsed neutron monochromatic beam, at the ET-RR-1 reactor, is produced by two 32 cm diameter rotors suspended in magnetic fields, whose centres are 126 cm apart rotating at speeds up to 16,000 rev/min. Each of the rotors has two slots, which are of constant cross-section in area - 7x10mm 2 , and are curved so that they have a maximum transmission for neutrons whose speed is 8.2 times that of the rotor tip. The jitter of the phase between the rotors at different rotation rates is found not to exceed +-1 μs. It has been found that both the observed time distribution and the TOF distribution of the neutrons at different rotation rates are in good agreement with the calculated ones. The observed intensity of the monochromatic neutrons of wavelength 2.74+-0.09 A, obtained by the rotors rotating at a speed of 10,500 rev/min with 864+-1 μs difference in phase between them, is 66.8 n/s. This value is found to be less than the predicted one by a factor of 5.5. (author)

  6. High energy neutron radiography

    International Nuclear Information System (INIS)

    Gavron, A.; Morley, K.; Morris, C.; Seestrom, S.; Ullmann, J.; Yates, G.; Zumbro, J.

    1996-01-01

    High-energy spallation neutron sources are now being considered in the US and elsewhere as a replacement for neutron beams produced by reactors. High-energy and high intensity neutron beams, produced by unmoderated spallation sources, open potential new vistas of neutron radiography. The authors discuss the basic advantages and disadvantages of high-energy neutron radiography, and consider some experimental results obtained at the Weapons Neutron Research (WNR) facility at Los Alamos

  7. Polycapillary neutron lenses

    International Nuclear Information System (INIS)

    Mildner, D.F.R.

    1997-01-01

    The principle of multiple mirror reflection from smooth surfaces at small grazing angles enables the transport and guiding of high intensity slow neutron beams to locations of low background for neutron scattering and absorption experiments and to provide facilities for multiple instruments. Curved guides have been widely used at cold neutron facilities to remove the unwanted radiation (fast neutrons and gamma rays) from the beam without the use of filters. A typical guide has transverse dimensions of 50 mm and, with a radius of curvature of 1 km, transmits wavelengths longer than 5 A. Much tighter curves requires narrower transverse dimensions, otherwise there is little transmission. Typical neutron benders have a number of slots with transverse dimensions of ∼5 mm. Based on the same principle but using a different technology, recent developments in glass polycapillary fibers have produced miniature versions of neutron guides. Fibers with many thousands of channels having sizes of ∼ 10 μm enable beams of long wavelength neutrons (λ > 4 A) to be transmitted efficiently in a radius of curvature as small as a fraction of 1 m. A large collection of these miniature versions of neutron guides can be used to bend the neutron trajectories such that the incident beam can be focused. (author)

  8. Effect of external magnetic field on critical current for the onset of virtual cathode oscillations in relativistic electron beams

    International Nuclear Information System (INIS)

    Hramov, Alexander; Koronovskii, Alexey; Morozov, Mikhail; Mushtakov, Alexander

    2008-01-01

    In this Letter we research the space charge limiting current value at which the oscillating virtual cathode is formed in the relativistic electron beam as a function of the external magnetic field guiding the beam electrons. It is shown that the space charge limiting (critical) current decreases with growth of the external magnetic field, and that there is an optimal induction value of the magnetic field at which the critical current for the onset of virtual cathode oscillations in the electron beam is minimum. For the strong external magnetic field the space charge limiting current corresponds to the analytical relation derived under the assumption that the motion of the electron beam is one-dimensional [D.J. Sullivan, J.E. Walsh, E. Coutsias, in: V.L. Granatstein, I. Alexeff (Eds.), Virtual Cathode Oscillator (Vircator) Theory, in: High Power Microwave Sources, vol. 13, Artech House Microwave Library, 1987, Chapter 13]. Such behavior is explained by the characteristic features of the dynamics of electron space charge in the longitudinal and radial directions in the drift space at the different external magnetic fields

  9. Unified model to predict flexural shear behavior of externally bonded RC beams

    International Nuclear Information System (INIS)

    Colotti, V.; Spadea, G.; Swamy, R.N.

    2006-01-01

    Structural strengthening with externally bonded reinforcement is now recognized as a cost-effective, structurally sound and practically efficient method of rehabilitating deteriorating and damaged reinforced concrete beams. There is now an urgent need to develop a sound engineering basis which can predict the failure loads of all such strengthened beams in a reliable and consistent manner. Existing models to predict the behavior at ultimate of strengthened beams suffer from many limitations and weaknesses. This paper presents a unified global model, based on the Strut-and-Tie approach, to predict the failure loads of reinforced concrete beams strengthened for flexure and/or shear. This structural model is based on rational engineering principles, considers all the possible failure modes, and incorporates the load transfer mechanism bond to reflect the debonding phenomena which has a dominant influence on the failure process of plated beams. The model is validated against about 200 strengthened beam test reported in the literature and failing in flexure and/or shear, involving a large number of structural variables and steel, carbon and glass fiber reinforced polymer laminates as reinforcing medium. (author)

  10. Calculated neutron spectrum from 800-MeV protons incident on a copper beam stop

    International Nuclear Information System (INIS)

    Perry, D.G.

    1975-10-01

    A Monte Carlo calculation was performed to obtain the neutron spectrum generated by 800-MeV protons incident on the LAMPF main copper beam stop. The total flux is calculated to be of the order of 10 13 n/cm 2 -sec-mA at full-beam intensity of 1 mA, with flux spectra calculated for angles of 20 0 , 30 0 , 60 0 , 90 0 , 120 0 , and 150 0 . (auth)

  11. External post-operational checks for the LHC beam dumping system

    International Nuclear Information System (INIS)

    Magnin, N.; Baggiolini, V.; Carlier, E.; Goddard, B.; Gorbonosov, R.; Khasbulatov, D.; Uythoven, J.; Zerlauth, M.

    2012-01-01

    The LHC Beam Dumping System (LBDS) is a critical part of the LHC machine protection system. After every LHC beam dump action the various signals and transient data recordings of the beam dumping control systems and beam instrumentation measurements are automatically analysed by the external Post-Operational Checks (XPOC) system to verify the correct execution of the dump action and the integrity of the related equipment. This software system complements the LHC machine protection hardware, and has to ascertain that the beam dumping system is 'as good as new' before the start of the next operational cycle. This is the only way by which the stringent reliability requirements can be met. The XPOC system has been developed within the framework of the LHC 'Post-Mortem' system, allowing highly dependable data acquisition, data archiving, live analysis of acquired data and replay of previously recorded events. It is composed of various analysis modules, each one dedicated to the analysis of measurements coming from specific equipment. This paper describes the global architecture of the XPOC system and gives examples of the analyses performed by some of the most important analysis modules. It explains the integration of the XPOC into the LHC control infrastructure along with its integration into the decision chain to allow proceeding with beam operation. Finally, it discusses the operational experience with the XPOC system acquired during the first years of LHC operation, and illustrates examples of internal system faults or abnormal beam dump executions which it has detected. (authors)

  12. T2-weighted endorectal magnetic resonance imaging of prostate cancer after external beam radiation therapy

    International Nuclear Information System (INIS)

    Westphalen, Antonio C.; Kurhanewicz, John; Cunha, Rui M.G.; Hsu, I-Chow; Kornak, John; Zhao, Shoujun; Coakley, Fergus V.

    2009-01-01

    Purpose: To retrospectively determine the accuracy of T2-weighted endorectal MR imaging in the detection of prostate cancer after external beam radiation therapy and to investigate the relationship between imaging accuracy and time since therapy. Materials and Methods: Institutional review board approval was obtained and the study was HIPPA compliant. We identified 59 patients who underwent 1.5 Tesla endorectal MR imaging of the prostate between 1999 and 2006 after definitive external beam radiation therapy for biopsy-proven prostate cancer. Two readers recorded the presence or absence of tumor on T2-weighted images. Logistic regression and Fisher's exact tests for 2x2 tables were used to determine the accuracy of imaging and investigate if accuracy differed between those imaged within 3 years of therapy (n = 25) and those imaged more than 3 years after therapy (n = 34). Transrectal biopsy was used as the standard of reference for the presence or absence of recurrent cancer. Results: Thirty-four of 59 patients (58%) had recurrent prostate cancer detected on biopsy. The overall accuracy of T2-weighted MR imaging in the detection cancer after external beam radiation therapy was 63% (37/59) for reader 1 and 71% for reader 2 (42/59). For both readers, logistic regression showed no difference in accuracy between those imaged within 3 years of therapy and those imaged more than 3 years after therapy (p = 0.86 for reader 1 and 0.44 for reader 2). Conclusion: T2-weighted endorectal MR imaging has low accuracy in the detection of prostate cancer after external beam radiation therapy, irrespective of the time since therapy. (author)

  13. Research of accelerator-based neutron source for boron neutron capture therapy

    International Nuclear Information System (INIS)

    Li Changkai; Ma Yingjie; Tang Xiaobin; Xie Qin; Geng Changran; Chen Da

    2013-01-01

    Background: 7 Li (p, n) reaction of high neutron yield and low threshold energy has become one of the most important neutron generating reactions for Accelerator-based Boron Neutron Capture Therapy (BNCT). Purpose Focuses on neutron yield and spectrum characteristics of this kind of neutron generating reaction which serves as an accelerator-based neutron source and moderates the high energy neutron beams to meet BNCT requirements. Methods: The yield and energy spectrum of neutrons generated by accelerator-based 7 Li(p, n) reaction with incident proton energy from 1.9 MeV to 3.0 MeV are researched using the Monte Carlo code-MCNPX2.5.0. And the energy and angular distribution of differential neutron yield by 2.5-MeV incident proton are also given in this part. In the following part, the character of epithermal neutron beam generated by 2.5-MeV incident protons is moderated by a new-designed moderator. Results: Energy spectra of neutrons generated by accelerator-based 7 Li(p, n) reaction with incident proton energy from 1.9 MeV to 3.0 MeV are got through the simulation and calculation. The best moderator thickness is got through comparison. Conclusions: Neutron beam produced by accelerator-based 7 Li(p, n) reaction, with the bombarding beam of 10 mA and the energy of 2.5 MeV, can meet the requirement of BNCT well after being moderated. (authors)

  14. Radical distributions in ammonium tartrate single crystals exposed to photon and neutron beams

    International Nuclear Information System (INIS)

    Marrale, M.; Longo, A.; Brai, M.; Barbon, A.; Brustolon, M.

    2014-01-01

    The radiation therapy carried out by means of heavy charged particles (such as carbon ions) and neutrons is rapidly becoming widespread worldwide. The success of these radiation therapies relies on the high density of energy released by these particles or by secondary particles produced after primary interaction with matter. The biological damages produced by ionising radiations in tissues and cells depend more properly on the energy released per unit pathlength, which is the linear energy transfer and which determines the radiation quality. To improve the therapy effectiveness, it is necessary to grasp the mechanisms of free radical production and distribution after irradiation with these particles when compared with the photon beams. In this work some preliminary results on the analysis of the spatial distributions of the free radicals produced after exposure of ammonium tartrate crystals to various radiation beams ( 60 Co gamma photons and thermal neutrons) were reported. Electron spin resonance analyses were performed by the electron spin echo technique, which allows the determination of local spin concentrations and by double electron-electron resonance technique, which is able to measure the spatial distance distribution (range 1.5-8 nm) among pairs of radicals in solids. The results of these analyses are discussed on the basis of the different distributions of free radicals produced by the two different radiation beams used. This paper extends to the single crystal case, a similar work done on AT powder irradiated with different beams, with assessment of microscopic radical concentration by determining the amount of ID contribution and obtaining the inter-radical distance distributions by double microwave irradiation. In this paper single crystals of AT have been exposed to 60 Co photons and neutrons. The results confirm that advanced pulse EPR techniques allow the direct measurement of the local free radical concentration and provide information about the

  15. Ion beam pellet fusion as a CTR neutron test source

    International Nuclear Information System (INIS)

    Arnold, R.; Martin, R.

    1975-07-01

    Pellet fusion, driven by nanosecond pulses containing α particles with 200 MeV energy, is being developed as a neutron source. A prototype system is in the conceptual design stage. During the coming year, engineering design of required accelerator components, storage rings, and pellet configurations, as well as experiments on energy deposition mechanisms, should be accomplished. Successful construction and tests of prototype rings, followed by two years of full scale system construction, would give a source producing a useful flux of fusion neutrons for materials testing. The system as currently envisioned would employ 100 small superconducting high field storage rings (15 cm radius, 140 kG field) which would be synchronously filled with circulating 1 nsec pulses from a 200 MeV linear accelerator over a period of 3 x 10 -4 sec. These ion pulses would all be simultaneously extracted, forming a total current of 10 kA, and focussed from all directions on a deuterium and tritium (DT) pellet with 0.17 mm radium, surrounded by a heavier (metal) coating to increase confinement time and aid compression efficiency. The overall repetition rate, limited principally by physical transport of the pellets, could reach 100/sec. Spacing between pellet and focussing elements would be about 1 m. The predominant engineering problems are the fast extraction mechanism and beam transport devices for the storage rings. Additional theoretical and experimental studies are required on the crucial energy deposition and transport mechanisms in pellets with ion beam heating before firm estimates can be given. Preliminary estimates suggest fusion neutron yields of at least 10 14 /sec and possibly 10 16 /sec are possible, with optimal pellet dynamics, but without the necessity for any large advances in the state-of-the-art in accelerator and storage ring design. (auth)

  16. Neutronics shielding analysis of the last mirror-beam duct system for a laser fusion power reactor

    International Nuclear Information System (INIS)

    Ragheb, M.M.H.; Klein, A.C.

    1981-01-01

    A Monte Carlo three-dimensional neutronics analysis for the last mirror-beam duct system for the SOLASE conceptual laser-driven fusion power reactor design is presented. Detailed geometric configurations including the reactor cavity, the two last mirrors, and the three-section two-right-angle bends duct are modeled. Measurements are given of the dimensions and compositions of the reactor components, and of neutron scalar fluxes, spatial dependencies and neutron volumetric heating rates for the cases of aluminum or Boral as laser beam duct liners, and ordinary concrete or lead mortar as shield material. A three-dimensional modeling of laser-driven reactor penetrations is employed. The particle leakage is found to be excessively high for the configuration of the conceptual design considered and the advantages and disadvantages of various solutions, such as the use of Boral as a duct liner and the use of lead mortar instead of ordinary concrete as a shield material, are considered

  17. Fast and slow neutrons in an 18-MV photon beam from a Philips SL/75-20 linear accelerator

    International Nuclear Information System (INIS)

    Gur, D.; Rosen, J.C.; Bukovitz, A.G.; Gill, A.W.

    1978-01-01

    Fast- and slow-neutron contamination in an 18-MV photon beam from a Philips SL/75-20 linear accelerator has been measured. Aluminum and indium foils were activated to determine fast- and slow-neutron fluence, which were largely independent of field sizes. Measured fast-neutron fluences were typically 13.9 x 10 4 and 4.4 x 10 4 neutrons/cm 2 /rad of x ray inside and 5 cm outside the field, respectively. Slow-neutron fluences, 1.3 x 10 4 neutrons/cm 2 /rad of x ray, remained relatively constant inside and outside the field. The reported results are about three times higher than neutron fluences recently reported with a betatron operated at the same energy

  18. A fan analyzer of neutron beam polarization on the spectrometer REMUR at the pulsed reactor IBR-2

    International Nuclear Information System (INIS)

    Ul'yanov, V.A.; Pusenkov, V.M.; Pleshanov, N.K.

    2004-01-01

    The new spectrometer of polarized neutrons REMUR has been created and put in operation at the Frank Laboratory of Neutron Physics (JINR, Dubna). The spectrometer is dedicated to investigations of multilayer structures and surfaces by registering the reflection of polarized neutrons and of the inhomogeneous state of solid matter by measuring the small-angle scattering of polarized neutrons. The spectrometer's working range of neutron wavelengths is 1.5-10 Angstroem. The spectrometer is equipped with a linear position-sensitive detector and a focused supermirror polarization analyzer (the fan-like polarization analyzer) with a solid angle of polarized neutron detection of 2.2·10 -4 rad. This paper describes the design and the principle of operation of the fan analyzer of neutron polarization together with the results of the fan tests on a polarized neutron beam

  19. Shear Strengthening of RC Deep Beam Using Externally Bonded GFRP Fabrics

    Science.gov (United States)

    Kumari, A.; Patel, S. S.; Nayak, A. N.

    2018-06-01

    This work presents the experimental investigation of RC deep beams wrapped with externally bonded Glass Fibre Reinforced Polymer (GFRP) fabrics in order to study the Load versus deflection behavior, cracking pattern, failure modes and ultimate shear strength. A total number of five deep beams have been casted, which is designed with conventional steel reinforcement as per IS: 456 (Indian standard plain and reinforced concrete—code for practice, Bureau of Indian Standards, New Delhi, 2000). The spans to depth ratio for all RC deep beams have been kept less than 2 as per the above specification. Out of five RC deep beams, one without retrofitting serves as a reference beam and the rest four have been wrapped with GFRP fabrics in multiple layers and tested with two point loading condition. The first cracking load, ultimate load and the shear contribution of GFRP to the deep beams have been observed. A critical discussion is made with respect to the enhancement of the strength, behaviour and performance of retrofitted deep beams in comparison to the deep beam without GFRP in order to explore the potential use of GFRP for strengthening the RC deep beams. Test results have demonstrated that the deep beams retrofitted with GFRP shows a slower development of the diagonal cracks and improves shear carrying capacity of the RC deep beam. A comparative study of the experimental results with the theoretical ones predicted by various researchers available in the literatures has also been presented. It is observed that the ultimate load of the beams retrofitted with GFRP fabrics increases with increase of number of GFRP layers up to a specific number of layers, i.e. 3 layers, beyond which it decreases.

  20. Effects of an energy broadened proton beam on the neutron distribution for the "7Li(p,n)"7Be reaction near threshold

    International Nuclear Information System (INIS)

    Shor, A.; Eisen, Y.; Berkovits, D.; Hirsh, T.; Feinberg, G.; Friedman, M.; Paul, M.; Krasa, A.; Giorginis, G.; Plompen, A.

    2011-01-01

    A common method for simulating the thermal neutron conditions in the stellar interior is based on the "7Li(p,n)"7Be reaction near threshold energy. Maxwellian-averaged neutron capture cross-sections of mean energy 25 keV, relevant to the s-process nucleosynthesis, are measured at existing Van-de-Graaff (VdG) proton accelerators. Soreq NRC Applied Research superconducting linear Accelerator Facility (SARAF) phase 1 is in its final stage of commissioning. Maxwellian averaged neutron capture cross-section measurements are planned to be conducted using a forced-flow closed-loop liquid-lithium target (LiLiT). The proton beam energy spread of RF linear accelerators, such as SARAF, is typically larger than the spread of proton beams of VdG accelerators. The energy spread of SARAF proton beam at 1912 keV is calculated to be of the order of 20-40 keV FWHM as compared to about 3 keV FWHM for VdG accelerators. For simulating the SARAF proton beam we performed an experiment at the IRMM-Geel VdG using a gold foil degrader positioned before the LiF target. This degrader shifts the mean proton energy to 1912 keV and it broadens the proton beam energy to values simulating the spread of the proton beam at SARAF. For calibrating the cross-sections we also performed a "7Li(p,n)"7Be experiment without the gold foil degrader at a proton energy of 1912 keV. The VdG was operated in a pulse mode and the neutron energies were determined by time-of-flight measurements using "6Li glass detectors. Detector efficiencies were obtained by Monte Carlo calculations. We present our study and compare the results for both narrow and broad energy proton beams. It is shown that the energy distribution for the broad-energy beam with a spread of 15 keV is similar to that of the distribution of the narrow energy beam and they peak nearly at the same energy. The broad-energy distribution has a tail extending to higher energies than that of the narrow-energy beam. It appears also that the neutron

  1. Propagation characteristics of a focused laser beam in a strontium barium niobate photorefractive crystal under reverse external electric field.

    Science.gov (United States)

    Guo, Q L; Liang, B L; Wang, Y; Deng, G Y; Jiang, Y H; Zhang, S H; Fu, G S; Simmonds, P J

    2014-10-01

    The propagation characteristics of a focused laser beam in a SBN:75 photorefractive crystal strongly depend on the signal-to-background intensity ratio (R=Is/Ib) under reverse external electric field. In the range 20>R>0.05, the laser beam shows enhanced self-defocusing behavior with increasing external electric field, while it shows self-focusing in the range 0.03>R>0.01. Spatial solitons are observed under a suitable reverse external electric field for R=0.025. A theoretical model is proposed to explain the experimental observations, which suggest a new type of soliton formation due to "enhancement" not "screening" of the external electrical field.

  2. Simulation of the Production of Secondary Particles from a Neutron Beam on Polyethylene Targets using the GEANT4 Simulation Tool

    CERN Document Server

    Ilgner, C

    2003-01-01

    In view of a beam test of RadFET semiconductor detectors and optically stimulated luminescence (OSL) detectors as on-line dosimeters for radiation monitoring purposes in the caverns of the Large Hadron Collider (LHC) experiments, a simulation on the production of secondary particles from a neutron beam on a polyethylene target was carried out. We describe the yield of recoil protons, scattered neutrons as well as electrons, positrons and photons, when neutrons of an average energy of 20 MeV hit polyethylene targets of several thicknesses. The simulation was carried out using the latest release 5.2 of the GEANT4 detector description and simulation tool, including advanced hadron interaction models.

  3. Research of isolated resonances using the average energy shift method for filtered neutron beam

    International Nuclear Information System (INIS)

    Gritzay, O.O.; Grymalo, A.K.; Kolotyi, V.V.; Mityushkin, O.O.; Venediktov, V.M.

    2010-01-01

    This work is devoted to detailed description of one of the research directions in the Neutron Physics Department (NPD), namely, to research of resonance parameters of isolated nuclear level at the filtered neutron beam on the horizontal experimental channel HEC-8 of the WWR-M reactor. Research of resonance parameters is an actual problem nowadays. This is because there are the essential differences between the resonance parameter values in the different evaluated nuclear data library (ENDL) for many nuclei. Research of resonance parameter is possible due to the set of the neutron cross sections received at the same filter, but with the slightly shifted filter average energy. The shift of the filter average energy is possible by several processes. In this work this shift is realized by neutron energy dependence on scattering angle. This method is provided by equipment.

  4. Cold neutron beam studies of parity-violation in the n-α and n-p systems

    International Nuclear Information System (INIS)

    Markoff, D.M.

    2001-01-01

    Long wavelength neutrons (λ>1 A) in a cold neutron beam provide a valuable probe to study the strong and weak nuclear forces in hadronic systems, where the description is complicated by the quark structure of the particles. As a consequence of parity-violation (PV) arising from the weak interaction, the low-energy neutron transverse spin-polarization vector rotates as the neutrons transverse a medium. The magnitude of the PV spin-rotation observable in the n-α system provides important new data to determine the strength of the neutron-nucleus weak interaction. Measurement of the spin-rotation in the bare neutron-proton system with a parahydrogen target, will provide important constraints on the weak nucleon-nucleon (NN) interaction including the neutral current contribution, and will increase our understanding of the strong NN interaction. This paper will review the recent spin-rotation measurement in a liquid helium target, and the proposed measurement in a parahydrogen target

  5. Cumulative beam break-up study of the spallation neutron source superconducting linac

    CERN Document Server

    Jeon, D; Krafft, G A; Yunn, B; Sundelin, R; Delayen, J; Kim, S; Doleans, M

    2002-01-01

    Beam instabilities due to High Order Modes (HOMs) are a concern to superconducting (SC) linacs such as the Spallation Neutron Source (SNS) linac. The effects of pulsed mode operation on transverse and longitudinal beam breakup instability are studied for H sup - beam in a consistent manner for the first time. Numerical simulation indicates that cumulative transverse beam breakup instabilities are not a concern in the SNS SC linac, primarily due to the heavy mass of H sup - beam and the HOM frequency spread resulting from manufacturing tolerances. As little as +-0.1 MHz HOM frequency spread stabilizes all the instabilities from both transverse HOMs, and also acts to stabilize the longitudinal HOMs. Such an assumed frequency spread of +-0.1 MHz HOM is small, and hence conservative compared with measured values of sigma=0.00109(f sub H sub O sub M -f sub 0)/f sub 0 obtained from Cornell and the Jefferson Lab Free Electron Laser cavities. However, a few cavities may hit resonance lines and generate a high heat lo...

  6. Relative measurements of fast neutron contamination in 18-MV photon beams from two linear accelerators and a betatron

    International Nuclear Information System (INIS)

    Gur, D.; Bukovitz, A.G.; Rosen, J.C.; Holmes, B.G.

    1979-01-01

    Fast neutron contamination in photon beams in the 20 MV range have been reported in recent years. In order to determine if the variations were due mainly to differences in measurement procedures, or inherent in the design of the accelerators, three different 18-MV (BJR) photon beams were compared using identical analytical techniques. The units studied were a Philips SL/75-20 and a Siemens Mevatron-20 linear accelerators and a Schimadzu betatron. Gamma spectroscopy of an activated aluminum foil was the method used. By comparing the relative amounts of neutron contamination, errors associated with absolute measurements such as detector efficiency and differences in activation foils were eliminated. Fast neutron contaminations per rad of x rays in a ratio of 6.7:3.7:1 were found for the Philips, Schimadzu and Siemens accelerators, respectively

  7. Strengthening of Reinforced Concrete Beam in Shear Zone by Compensation the Stirrups with Equivalent External Steel Plates

    Directory of Open Access Journals (Sweden)

    Khamail Abdul-Mahdi Mosheer

    2016-09-01

    Full Text Available An experimental study on reinforced concrete beams strengthened with external steel plates instead of shear stirrups has been held in this paper. Eight samples of the same dimensions and properties were used. Two of them were tested up to failure and specified as references beams; one with shear reinforcement and the other without shear reinforcement. Another samples without shear reinforcement were tested until the first shear crack occurs, then the samples strengthened on both sides with external steel plates as equivalent area of removed stirrups. The strengthened beams were divided into three groups according to the thickness of plates (1, 1.5, 2 mm, each group involved two beams; one bonded using epoxy and the other bonded using epoxy with anchored bolts. Finally, the strengthened beams tested when using anchored bolts with epoxy glue to bond plates. Where the increasing in maximum load is higher than that in reference beam with no internal stirrups reach to (75.46 –106.13% and has a good agreement with the control beam with shear reinforcement reach to (76.06 – 89.36% of ultimate load.

  8. Polarized neutrons

    International Nuclear Information System (INIS)

    Williams, W.G.

    1988-01-01

    The book on 'polarized neutrons' is intended to inform researchers in condensed matter physics and chemistry of the diversity of scientific problems that can be investigated using polarized neutron beams. The contents include chapters on:- neutron polarizers and instrumentation, polarized neutron scattering, neutron polarization analysis experiments and precessing neutron polarization. (U.K.)

  9. A long neutron optical horn for the ILL neutron-antineutron oscillation experiment

    International Nuclear Information System (INIS)

    Bitter, T.; Eisert, F.; El-Muzeini, P.; Kessler, M.; Klemt, E.; Lippert, W.; Meienburg, W.; Dubbers, D.

    1992-01-01

    In the neutron-antineutron oscillation experiment at ILL the divergence of the free flying cold neutron beam was strongly reduced without loss of intensity by the use of a 34 m long neutron-optical horn system. The divergence reduction was accurately studied in order to maintain the total width of the neutron beam below 1.1 m after a neutron free flight distance of about 80 m. The fabrication and performance of this system are described. (orig.)

  10. The neutron beam users tape management system

    International Nuclear Information System (INIS)

    Lyall, B.; Johnson, M.W.

    1977-02-01

    Systems are described for dealing with data collected at the High Flux Reactor, Institut Laue-Langevin, Grenoble and brought on magnetic tape to the Neutron Beam Research Unit at the Rutherford Laboratory. The first system, named GNAT, was designed to archive the incoming 800 bpi tapes onto 6250 bpi tapes (to enable them to return to the ILL). The archiving program, besides choosing the archive tapes, keeping a record of the data sets archived, and writing the archive tape, should be able to cope with incoming tapes whose formats are somewhat different from the standard IBM format. The second system, named FONT, was designed to maintain a record of all the tapes in the NBRU's possession, their whereabouts and what data, if any, are on them. (U.K.)

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

    Directory of Open Access Journals (Sweden)

    Malone R.C.

    2016-01-01

    We are conducting new measurements of the cross section for nn QFS in nd breakup. The measurements are performed at incident neutron beam energies below 20 MeV. The neutron beam is produced via the 2H(d, n3He reaction. The target is a deuterated plastic cylinder. Our measurements utilize time-of-flight techniques with a pulsed neutron beam and detection of the two emitted neutrons in coincidence. A description of our initial measurements at 10 MeV for a single scattering angle will be presented along with preliminary results. Also, plans for measurements at other energies with broad angular coverage will be discussed.

  12. Improved Dose Targeting for a Clinical Epithermal Neutron Capture Beam Using Optional 6Li Filtration

    International Nuclear Information System (INIS)

    Binns, Peter J.; Riley, Kent J.; Ostrovsky, Yakov; Gao Wei; Albritton, J. Raymond; Kiger, W.S.; Harling, Otto K.

    2007-01-01

    Purpose: The aim of this study was to construct a 6 Li filter and to improve penetration of thermal neutrons produced by the fission converter-based epithermal neutron beam (FCB) for brain irradiation during boron neutron capture therapy (BNCT). Methods and Materials: Design of the 6 Li filter was evaluated using Monte Carlo simulations of the existing beam line and radiation transport through an ellipsoidal water phantom. Changes in beam performance were determined using three figures of merit: (1) advantage depth (AD), the depth at which the total biologically weighted dose to tumor equals the maximum weighted dose to normal tissue; (2) advantage ratio (AR), the ratio of the integral tumor dose to that of normal tissue averaged from the surface to the AD; and (3) advantage depth dose rate (ADDR), the therapeutic dose rate at the AD. Dosimetry performed with the new filter installed provided calibration data for treatment planning. Past treatment plans were recalculated to illustrate the clinical potential of the filter. Results: The 8-mm-thick Li filter is more effective for smaller field sizes, increasing the AD from 9.3 to 9.9 cm, leaving the AR unchanged at 5.7 but decreasing the ADDR from 114 to 55 cGy min -1 for the 12 cm diameter aperture. Using the filter increases the minimum deliverable dose to deep seated tumors by up to 9% for the same maximum dose to normal tissue. Conclusions: Optional 6 Li filtration provides an incremental improvement in clinical beam performance of the FCB that could help to establish a therapeutic window in the future treatment of deep-seated tumors

  13. Neutronics design of accelerator-driven system for power flattening and beam current reduction

    International Nuclear Information System (INIS)

    Nishihara, Kenji; Iwanaga, Kohei; Tsujimoto, Kazufumi; Kurata, Yuji; Oigawa, Hiroyuki; Iwasaki, Tomohiko

    2008-01-01

    In the present neutronics design of the Accelerator-Driven System (ADS) cooled by lead-bismuth eutectic (LBE), we investigated several methods to reduce the power peak and beam current, and estimated the temperature reductions of the cladding tube and beam window from the conventional design. The methods are adjustment of inert matrix ratio in fuel in each burn-up cycle, multiregion design in terms of pin radius or inert matrix content, and modification of the level of the beam window position and the height of the central fuel assemblies. As a result, we optimized the ADS combined with the adjustment of the inert matrix ratio in each burn-up cycle, multiregion design in terms of inert matrix content and deepened window level. The maximum temperatures of the optimized ADS at the surface of the cladding tube and the beam window were reduced by 91 and 38degC, respectively. The maximum beam current was improved from 20.3 to 15.6 mA. (author)

  14. PIXE/PIGE characterisation of emeralds using an external micro-beam

    International Nuclear Information System (INIS)

    Calligaro, T.; Dran, J.-C.; Poirot, J.-P.; Querre, G.; Salomon, J.; Zwaan, J.C.

    2000-01-01

    A large collection of emeralds of various occurrences has been analysed by PIXE/PIGE in view to establish a compositional database. Major elements (Be, Si, Al) and trace elements (Li, F, Na, Mg, Ca, Rb, Cs and transition metals) are determined using an external 3 MeV proton micro-beam. Elemental micro-mapping permits to select the useful provenance tracers. This database was applied to infer the origin of several ancient emeralds set on historical jewels

  15. SU-E-J-181: Effect of Prostate Motion On Combined Brachytherapy and External Beam Dose Based On Daily Motion of the Prostate

    Energy Technology Data Exchange (ETDEWEB)

    Narayana, V; McLaughlin, P [Providence Cancer Center, Southfield, MI (United States); University of Michigan, Ann Arbor, MI (United States); Ealbaj, J [University of Michigan, Ann Arbor, MI (United States)

    2015-06-15

    Purpose: In this study, the adequacy of target expansions on the combined external beam and implant dose was examined based on the measured daily motion of the prostate. Methods: Thirty patients received an I–125 prostate implant prescribed to dose of 90Gy. This was followed by external beam to deliver a dose of 90Gyeq (external beam equivalent) to the prostate over 25 to 30 fractions. An ideal IMRT plan was developed by optimizing the external beam dose based on the delivered implant dose. The implant dose was converted to an equivalent external beam dose using the linear quadratic model. Patients were set up on the treatment table by daily orthogonal imaging and aligning the marker seeds in the prostate. Orthogonal images were obtained at the end of treatment to assess prostate intrafraction motion. Based on the observed motion of the markers between the initial and final images, 5 individual plans showing the actual dose delivered to the patient were calculated. A final true dose distribution was established based on summing the implant dose and the 5 external beam plans. Dose to the prostate, seminal vesicles, lymphnodes and normal tissues, rectal wall, urethra and lower sphincter were calculated and compared to ideal. On 18 patients who were sexually active, dose to the corpus cavernosum and internal pudendal artery was also calculated. Results: The average prostate motion in 3 orthogonal directions was less than 1 mm with a standard deviation of less than +2 mm. Dose and volume parameters showed that there was no decrease in dose to the targets and a marginal decrease in dose to in normal tissues. Conclusion: Dose delivered by seed implant moves with the prostate, decreasing the impact of intrafractions dose movement on actual dose delivered. Combined brachytherapy and external beam dose delivered to the prostate was not sensitive to prostate motion.

  16. 235U Determination using In-Beam Delayed Neutron Counting Technique at the NRU Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, M. T. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Bentoumi, G. [Canadian Nuclear Labs., Chalk River, ON (Canada); Corcoran, E. C. [Royal Military College of Canada, Kingston, ON (United States); Dimayuga, I. [Canadian Nuclear Labs., Chalk River, ON (Canada); Kelly, D. G. [Royal Military College of Canada, Kingston, ON (United States); Li, L. [Canadian Nuclear Labs., Chalk River, ON (Canada); Sur, B. [Canadian Nuclear Labs., Chalk River, ON (Canada); Rogge, R. B. [Canadian Nuclear Labs., Chalk River, ON (Canada)

    2015-11-17

    This paper describes a collaborative effort that saw the Royal Military College of Canada (RMC)’s delayed neutron and gamma counting apparatus transported to Canadian Nuclear Laboratories (CNL) for use in the neutron beamline at the National Research Universal (NRU) reactor. Samples containing mg quantities of fissile material were re-interrogated, and their delayed neutron emissions measured. This collaboration offers significant advantages to previous delayed neutron research at both CNL and RMC. This paper details the determination of 235U content in enriched uranium via the assay of in-beam delayed neutron magnitudes and temporal behavior. 235U mass was determined with an average absolute error of ± 2.7 %. This error is lower than that obtained at RMCC for the assay of 235U content in aqueous solutions (3.6 %) using delayed neutron counting. Delayed neutron counting has been demonstrated to be a rapid, accurate, and precise method for special nuclear material detection and identification.

  17. The effect of combined external beam and high-dose intracavitary brachytherapy on dysphagia and survival in patients with advanced esophageal cancer

    International Nuclear Information System (INIS)

    Yorozu, Atsunori; Dokiya, Takushi; Ogita, Mikio; Kutsuki, Shoji

    1996-01-01

    During an 11-year period, a group of 130 patients with esophageal cancer of stages 2 to 4 were treated with external beam irradiation (40 to 60 Gy) followed by boost dose of 10 to 20 Gy of high-dose intracavitary brachytherapy. The overall 2-year survival rate was 15.4%. The significant prognostic factors were tumor size, response to external beam irradiation, pretreatment dysphagia score, and presence of distant metastases. The palliative effect was excellent; the dysphagia scores of 122 of 130 patients (93.8%) improved. The significant palliative factors were response to external beam irradiation and pretreatment dysphagia score. Tracheoesophageal fistulas developed after treatment in 13 of 130 patients (10%); 3 of the fistulas were probably related to radiotherapy. We conclude that intracavitary brachytherapy is useful in the treatment of cases of advanced cancer which show a good response to external beam irradiation and may be curative in patients with mild dysphagia. (author)

  18. A large angle cold neutron bender using sequential garland reflections for pulsed neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Ebisawa, T.; Tasaki, S. [Kyoto Univ., Kumatori, Osaka (Japan). Research Reactor Inst; Soyama, K.; Suzuki, J. [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2001-03-01

    We discuss a basic structure and performance of a new cold neutron bender using sequential garland reflections, in order to bend a neutron beam with large divergence by large angle. Using this bender for a pulsed neutron source we could not only avoid the frame overlap for cold neutrons but also install a plural spectrometers at a cold guide and obtain polarized neutron beams if necessary. (author)

  19. A large angle cold neutron bender using sequential garland reflections for pulsed neutron source

    International Nuclear Information System (INIS)

    Ebisawa, T.; Tasaki, S.; Soyama, K.; Suzuki, J.

    2001-01-01

    We discuss a basic structure and performance of a new cold neutron bender using sequential garland reflections, in order to bend a neutron beam with large divergence by large angle. Using this bender for a pulsed neutron source we could not only avoid the frame overlap for cold neutrons but also install a plural spectrometers at a cold guide and obtain polarized neutron beams if necessary. (author)

  20. The GENEPI-MASURCA coupling for the neutronic investigations of subcritical multiplying media in presence of an external neutron source: The MUSE experiments

    International Nuclear Information System (INIS)

    Soule, R.; Granget, G.; Chauvin, J.P.

    1999-01-01

    Full text: Accelerator Driven Systems (ADS) are being explored in France in the frame of the research program on radioactive waste management options. Besides studies aimed to clarify the motivations for ADS, a significant program has been started to validate experimentally the main physics principles of these systems. This program was initiated at CEA Cadarache in 1995, with the sponsorship of EdF and Framatome. Since 1997, the CNRS has joined the program, which is now a common CEA-CNRS- EdF-Framatome program, open to external partners, in particular the European Community in the frame of the 5th FW Program. The experimental programs allow to validate nuclear data and calculation methods used to describe the sub-critical core, in terms of reactivity, spatial flux distributions, neutron spectra and external source worth. If the source can be used in continuous and pulsed modes, static and dynamic reactivity measurements are possible. This point is of relevance, since the experimental investigation of the different techniques to monitor the sub-criticality level during the operation of an ADS is still an open question. The future MUSE program will enter a new phase in november 1999, with the installation at MASURCA of a deuteron accelerator (GENEPI accelerator), developed at the CNRS/IN2P3/ISN of Grenoble. Improved performances are expected (in terms of the quality of the neutron pulse and source intensity), and the use of both (D,D) and (D,T) reactions, will enable to explore different neutron spectra as well as source worths and their ratios to the fission neutron worths. The paper presents the GENEPI accelerator characteristics and monitoring and the experimental configurations defined for the next phase of the MUSE experiments. (author)