WorldWideScience

Sample records for low-temperature neutron irradiation

  1. Tensile properties of Inconel 718 after low temperature neutron irradiation

    Science.gov (United States)

    Byun, T. S.; Farrell, K.

    2003-05-01

    Tensile properties of Inconel 718 (IN718) have been investigated after neutron irradiation to 0.0006-1.2 dpa at 60-100 °C in the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL). The alloy was exposed in solution-annealed (SA) and precipitation-hardened (PH) conditions. Before irradiation, the yield strength of PH IN718 was about 1170 MPa, which was 3.7 times higher than that of SA IN718. In the SA condition, an almost threefold increase in yield strength was found at 1.2 dpa, but the alloy retained a positive strain-hardening capability and a uniform ductility of more than 20%. Comparisons showed that the strain-hardening behavior of the SA IN718 is similar to that of a SA 316LN austenitic stainless steel. In the PH condition, the IN718 displayed no radiation-induced hardening in yield strength and significant softening in ultimate tensile strength. The strain-hardening capability of the PH IN718 decreased with dose as the radiation-induced dissolution of precipitates occurred, which resulted in the onset of plastic instability at strains less than 1% after irradiation to 0.16 or 1.2 dpa. An analysis on plastic instability indicated that the loss of uniform ductility in PH IN718 was largely due to the reduction in strain-hardening rate, while in SA IN718 and SA 316LN stainless steel it resulted primarily from the increase of yield stress.

  2. Low Temperature Hall Measurements of Neutron Irradiated Silicon Carbide

    Science.gov (United States)

    2004-03-01

    neutron absorption cross section . Silicon and carbon both possess small neutron absorption cross sections. Additionally, most silicon and...0 4 1.0E+0 5 1.0E+0 6 1.0E+0 7 1.0E+0 8 Neutron Energy [eV] C a p tu re C ro ss S e ct io n [ b a rn s] Figure 17: Cadmium neutron absorption cross section as... absorption cross section as a function of energy. Cadmium has the unique property of a large thermal cross

  3. Low Temperature Irradiation Applied to Neutron Activation Analysis of Mercury In Human Whole Blood

    Energy Technology Data Exchange (ETDEWEB)

    Brune, D.

    1966-02-15

    The distribution of mercury in human whole blood has been studied by means of neutron activation analysis. During the irradiation procedure the samples were kept at low temperature by freezing them in a cooling device in order to prevent interferences caused by volatilization and contamination. The mercury activity was separated by means of distillation and ion exchange techniques.

  4. Low temperature testing and neutron irradiation of a swept charge device on board the HXMT satellite

    Institute of Scientific and Technical Information of China (English)

    WANG Yu-Sa; CHEN Tian-Xiang; LI Cheng-Kui; HUO Jia; LI Zheng-Wei; LI Wei; HU Wei; ZHANG Yi; LU Bo; ZHU Yue; LIU Yan; CHEN Yong; WU Di; SUN Qing-Rong; ZHANG Zi-Liang; XU Yu-Peng; YANG Yan-Ji; CUI Wei-Wei; LI Mao-Shun; LIU Xiao-Yan; WANG Juan; HAN Da-Wei

    2012-01-01

    We present the low temperature testing of an SCD detector,investigating its performance such as readout noise,energy resolution at 5.9 keV and dark current.The SCD's performance is closely related to temperature,and the temperature range of -80 ℃ to -50 ℃ is the best choice,where the FWHM at 5.9 keV is about 130 eV.The influence of the neutron irradiation from an electrostatic accelerator with fluence up to 1 × 109 cm-2 has been examined.We find the SCD is not vulnerable to neutron irradiation.The detailed operations of the SCD and the test results of low temperature are reported,and the results of neutron irradiation are discussed.

  5. Temperature dependence of the deformation behavior of 316 stainless steel after low temperature neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Pawel-Robertson, J.E.; Rowcliffe, A.F.; Grossbeck, M.L. [Oak Ridge National Lab., TN (United States)] [and others

    1996-10-01

    The effects of low temperature neutron irradiation on the tensile behavior of 316 stainless steel have been investigated. A single heat of solution annealed 316 was irradiated to 7 and 18 dpa at 60, 200, 330, and 400{degrees}C. The tensile properties as a function of dose and as a function of temperature were examined. Large changes in yield strength, deformation mode, strain to necking, and strain hardening capacity were seen in this irradiation experiment. The magnitudes of the changes are dependent on both irradiation temperature and neutron dose. Irradiation can more than triple the yield strength over the unirradiated value and decrease the strain to necking (STN) to less than 0.5% under certain conditions. A maximum increase in yield strength and a minimum in the STN occur after irradiation at 330{degrees}C but the failure mode remains ductile.

  6. Defect evolution in single crystalline tungsten following low temperature and low dose neutron irradiation

    Science.gov (United States)

    Hu, Xunxiang; Koyanagi, Takaaki; Fukuda, Makoto; Katoh, Yutai; Snead, Lance L.; Wirth, Brian D.

    2016-03-01

    The tungsten plasma-facing components of fusion reactors will experience an extreme environment including high temperature, intense particle fluxes of gas atoms, high-energy neutron irradiation, and significant cyclic stress loading. Irradiation-induced defect accumulation resulting in severe thermo-mechanical property degradation is expected. For this reason, and because of the lack of relevant fusion neutron sources, the fundamentals of tungsten radiation damage must be understood through coordinated mixed-spectrum fission reactor irradiation experiments and modeling. In this study, high-purity (110) single-crystal tungsten was examined by positron annihilation spectroscopy and transmission electron microscopy following low-temperature (∼90 °C) and low-dose (0.006 and 0.03 dpa) mixed-spectrum neutron irradiation and subsequent isochronal annealing at 400, 500, 650, 800, 1000, 1150, and 1300 °C. The results provide insights into microstructural and defect evolution, thus identifying the mechanisms of different annealing behavior. Following 1 h annealing, ex situ characterization of vacancy defects using positron lifetime spectroscopy and coincidence Doppler broadening was performed. The vacancy cluster size distributions indicated intense vacancy clustering at 400 °C with significant damage recovery around 1000 °C. Coincidence Doppler broadening measurements confirm the trend of the vacancy defect evolution, and the S-W plots indicate that only a single type of vacancy cluster is present. Furthermore, transmission electron microscopy observations at selected annealing conditions provide supplemental information on dislocation loop populations and visible void formation. This microstructural information is consistent with the measured irradiation-induced hardening at each annealing stage, providing insight into tungsten hardening and embrittlement due to irradiation-induced matrix defects.

  7. Optical properties of CsI single crystals irradiated with neutrons at low temperature

    Energy Technology Data Exchange (ETDEWEB)

    Okada, M. [Kyoto Univ., Kumatori, Osaka (Japan). Research Reactor Inst.; Nakagawa, M. [Faculty of Education, Kagawa Univ., Takamatsu, Kagawa (Japan); Atobe, K. [Faculty of Science, Naruto Univ. of Education, Naruto, Tokushima (Japan); Itatani, N.; Ozawa, K. [Horiba Ltd., Minamiku, Kyoto (Japan)

    1998-05-01

    Optical properties of the irradiation-induced-defects in neutron-irradiated CsI single crystals have been investigated. The nominally pure CsI crystals are irradiated by reactor fast neutrons (E>0.1 MeV) with a fluence of 1.4 x 10{sup 15} n/cm{sup 2} at 20 K and by {gamma}-rays from {sup 60}Co source to a dose of 1.5 x 10{sup 4} Gy at liquid nitrogen temperature (LNT). After the irradiations, isochronal annealings are performed to investigate the thermal behavior of the defects. The glow peaks of the thermoluminescence (TL) in each sample irradiated with neutrons at 20 K and with {gamma}-rays at LNT are observed at about 100, 160 and 220 K. In the neutron-irradiated samples at 20 K, the emission band at 338 nm is observed at LNT. It is supposed that this emission band occurs by an excitation of {gamma}-rays from {sup 134}Cs, which is radioactivated by thermal neutrons among the reactor radiations. It is confirmed that the temperature dependence of the 338 nm band is similar with that of the emission band due to the self-trapped exciton which is introduced into the non-irradiated samples illuminated by higher energy photons. (orig.) 13 refs.

  8. Effects of low-temperature neutron irradiation on the mechanical properties of BCC metals

    Science.gov (United States)

    Kitajima, K.; Abe, H.; Aono, Y.; Kuramoto, E.; Takamura, S.

    1982-08-01

    Tensile properties, together with the effects of point-irradiation annealings on them, were measured on single crystals of pure iron, iron containing 200 at. ppm carbon, and pure molybdenum, which were irradiated at 5 K in reactor JRR-3 and stored at 77 K, at the test temperatures of 4.2-800 K. Their measurements were compared with those irradiated by 2.5 and 28 MeV electrons at 77 K to elucidate the characteristics of neutron irradiation. Interpretations were then presented for the mechanisms of softening and hardening based on the interactions of defects and defect clusters formed in various annealing stages with screw dislocation in bcc metals.

  9. Low-temperature properties of neutron irradiated CuGeO3 single crystals

    Science.gov (United States)

    Gladczuk, L.; Mosiniewicz-Szablewska, E.; Dabkowska, H.; Baran, M.; Pytel, B.; Szymczak, R.; Szymczak, H.

    2000-07-01

    The effect of neutron irradiation on the magnetic properties of CuGeO3 single crystal which shows the spin-Peierls transition below T sp=14 K was investigated by means of electron paramagnetic resonance (EPR) and susceptibility measurements. It was found that the irradiation led to a decrease of the spin-Peierls transition temperature and induced appreciable changes in the EPR signal intensity, resonance linewidth, g-factor and magnetic susceptibility of this material. These changes may be associated with a partial suppression of both the energy gap and the dimerization within the Cu chains.

  10. Effects of low temperature neutron irradiation on deformation behavior of austenitic stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Pawel, J.E.; Rowcliffe, A.F.; Alexander, D.J.; Grossbeck, M.L. [Oak Ridge National Laboratory, TN (United States); Shiba, K.

    1996-04-01

    An austenitic stainless steel, designated 316LN-IG, has been chosen for the first wall/shield (FW/S) structure for the International Thermonuclear Experimental Reactor (ITER). The proposed operational temperature range for the structure (100 to 250{degree}C) is below the temperature regimes for void swelling (400-600{degree}C) and for helium embrittlement (500-700{degree}C). However, the proposed neutron dose is such that large changes in yield strength, deformation mode, and strain hardening capacity could be encountered which could significantly affect fracture properties. Definition of the irradiation regimes in which this phenomenon occurs is essential to the establishment of design rules to protect against various modes of failure.

  11. Microstructure of V-4Cr-4Ti alloy after low-temperature irradiation by ions and neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Gazda, J.; Meshii, M. [Northwestern Univ. (United States); Chung, H.M. [Argonne National Lab., IL (United States)

    1998-03-01

    Mechanical properties of V-4Cr-4Ti alloy were investigated after low-temperature (<420 C) irradiation. The effects of fast neutrons at 390 C were investigated by irradiation to {approx}4 dpa in the X530 experiment in the EBR-II reactor; these tests were complemented by irradiation with single (4.5-MeV Ni{sup ++}) and dual ion beams (350-keV He{sup +} simultaneously with 4.5-MeV Ni{sup ++}). TEM observations showed the formation of a high density of point-defect clusters and dislocation loops (<30 nm diameter) distributed uniformly in the specimens. Mechanical-property testing showed embrittlement of the alloy. TEM investigations of deformed microstructures were used to determine the causes of embrittlement and yielded observation of dislocation channels propagating through the undeformed matrix. Channels are the sole slip paths and cause early onset of necking and loss of work-hardening in this alloy. Based on a review of the available literature, suggestions are made for further research of slip localization in V-base alloys.

  12. Final report on neutron irradiation at low temperature to investigate plastic instability and at high temperature to study caviation

    DEFF Research Database (Denmark)

    Singh, B.N; Eldrup, Morten Mostgaard; Golubov, D.J.

    2005-01-01

    Effects of neutron irradiation on defect accumulation and physical and mechanical properties of pure iron and F82H and EUROFER 97 ferritic-martensitic steels have been investigated. Tensile specimens were neutron irradiated to a dose level of 0,23 dpa at333 and 573 K. Electrical resistivity...... and tensile properties were measured both in the unirradiated and irradiated condition. Some additional specimens of pure iron were irradiated at 333 K to doses of 10-3, 10-2 and 10-1 dpa and tensile tested at 333 K.To investigate the effect of helium on cavity nucleation and growth, specimens of pure iron...... and EUROFER 97 were implanted with different amounts of helium at 323 K and subsequently neutron irradiated to doses of 10-3, 10-2 and 10-1 dpa at 323 K. Defectmicrostructures were investigated using positron annihilation spectroscopy (PAS) and transmission electron microscopy (TEM). Numerical calculations...

  13. Accumulation and annealing of radiation defects under low-temperature electron and neutron irradiation of ODS steel and Fe-Cr alloys

    Science.gov (United States)

    Arbuzov, V. L.; Goshchitskii, B. N.; Sagaradze, V. V.; Danilov, S. E.; Kar'kin, A. E.

    2010-10-01

    The processes of accumulation and annealing of radiation defects at low-temperature (77 K) electron and neutron irradiation and their effect on the physicomechanical properties of Fe-Cr alloys and oxide dispersion strengthened (ODS) steel have been studied. It has been shown that the behavior of radiation defects in ODS steel and Fe-Cr alloys is qualitatively similar. Above 250 K, radiation-induced processes of the solid solution decomposition become conspicuous. These processes are much less pronounced in ODS steel because of specific features of its microstructure. Processes related to the overlapping of displacement cascades under neutron irradiation have been considered. It has been shown that, in this case, it is the increase in the size of vacancy clusters, rather than the growth of their concentration, that is prevailing. Possible mechanisms of the radiation hardening of the ODS steel and the Fe-13Cr alloy upon irradiation and subsequent annealing have been discussed.

  14. Low-temperature low-dose neutron irradiation effects on Brush Wellman S65-C and Kawechi Berylco P0 beryllium

    Energy Technology Data Exchange (ETDEWEB)

    Snead, L.L. [Oak Ridge National Lab., TN (United States)

    1998-09-01

    The mechanical property results for two high quality beryllium materials subjected to low temperature, low dose neutron irradiation in water moderated reactors are presented. Materials chosen were the S65-C ITER candidate material produced by Brush Wellman, and Kawecki Berylco Industries P0 beryllium. Both materials were processed by vacuum hot pressing. Mini sheet tensile and thermal diffusivity specimens were irradiated in the temperature range of {approximately}100--275 C from a fast (E > 0.1 MeV) neutron dose of 0.05 to 1.0 {times} 10{sup 25} n/m{sup 2} in the High Flux Isotope Reactor (HFIR) at the Oak Ridge National Laboratory and the High Flux Beam Reactor (HFBR) at the Brookhaven National Laboratory. As expected from earlier work on beryllium, both materials underwent significant embrittlement with corresponding reduction in ductility and increased strength. Both thermal diffusivity and volumetric expansion were measured and found to be negligible in this temperature and fluence range. Of significance from this work is that while both materials rapidly embrittle at these ITER relevant irradiation conditions, some ductility (>1--2%) remains, which contrasts with a body of earlier work including recent work on the Brush-Wellman S65-C material irradiated to slightly higher neutron fluence.

  15. Minimizing material damage using low temperature irradiation

    Science.gov (United States)

    Craven, E.; Hasanain, F.; Winters, M.

    2012-08-01

    Scientific advancements in healthcare driven both by technological breakthroughs and an aging and increasingly obese population have lead to a changing medical device market. Complex products and devices are being developed to meet the demands of leading edge medical procedures. Specialized materials in these medical devices, including pharmaceuticals and biologics as well as exotic polymers present a challenge for radiation sterilization as many of these components cannot withstand conventional irradiation methods. The irradiation of materials at dry ice temperatures has emerged as a technique that can be used to decrease the radiation sensitivity of materials. The purpose of this study is to examine the effect of low temperature irradiation on a variety of polymer materials, and over a range of temperatures from 0 °C down to -80 °C. The effectiveness of microbial kill is also investigated under each of these conditions. The results of the study show that the effect of low temperature irradiation is material dependent and can alter the balance between crosslinking and chain scission of the polymer. Low temperatures also increase the dose required to achieve an equivalent microbiological kill, therefore dose setting exercises must be performed under the environmental conditions of use.

  16. Characterization of neutron transmutation doped (NTD) Ge for low temperature sensor development

    CERN Document Server

    Mathimalar, S; Dokania, N; Nanal, V; Pillay, R G; Pal, S; Ramakrishnan, S; Shrivastava, A; Maheshwari, Priya; Pujari, P K; Ojha, S; Kanjilal, D; Jagadeesan, K C; Thakare, S V

    2014-01-01

    Development of NTD Ge sensors has been initiated for low temperature (mK) thermometry in The India-based Tin detector (TIN.TIN). NTD Ge sensors are prepared by thermal neutron irradiation of device grade Ge samples at Dhruva reactor, BARC, Mumbai. Detailed measurements have been carried out in irradiated samples for estimating the carrier concentration and fast neutron induced defects. The Positron Annihilation Lifetime Spectroscopy (PALS) measurements indicated monovacancy type defects for all irradiated samples, while Channeling studies employing RBS with 2 MeV alpha particles, revealed no significant defects in the samples exposed to fast neutron fluence of $\\sim 4\\times10^{16}/cm^2$. Both PALS and Channeling studies have shown that vacuum annealing at 600 $^\\circ$C for $\\sim2$ hours is sufficient to recover the damage in the irradiated samples, thereby making them suitable for the sensor development.

  17. Thermal conductivity degradation of graphites irradiated at low temperature

    Energy Technology Data Exchange (ETDEWEB)

    Snead, L.L.; Burchell, T.D. [Oak Ridge National Lab., TN (United States)

    1995-04-01

    The objective of this work is to study the thermal conductivity degradation of new, high thermal conductivity graphites and to compare these results to more standard graphites irradiated at low temperatures. Several graphites and graphite composites (C/C`s) have been irradiated near 150{degree}C and at fluences up to a displacement level of 0.24 dpa. The materials ranged in unirradiated room temperature thermal conductivity of these materials varied from 114 W/m-K for H-451 isotropic graphite, to 670 W/m-K for unidirectional FMI-1D C/C composite. At the irradiation temperature a saturation reduction in thermal conductivity was seen to occur at displacement levels of approximately 0.1 dpa. All materials were seen to degrade to approximately 10 to 14 % of their original thermal conductivity after irradiation. The effect of post irradiation annealing on the thermal conductivity was also studied.

  18. Possibility for low temperature fluid-wall neutron bottle with very low neutron upscattering losses

    CERN Document Server

    Pokotilovski, Yu N

    1999-01-01

    The new recently synthesized polymers - perfluorinated polyformaldehydes have long liquid range and low melting point. Due to the expected low upscattering losses of ultracold neutrons, at low temperatures, these fluids may be good candidates for precision measurement of neutron lifetime by the method of storage of ultracold neutrons in traps.

  19. Tensile and impact properties of vanadium-base alloys irradiated at low temperatures in the ATR-A1 experiment

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, H.; Nowicki, L.J.; Billone, M.C.; Chung, H.M.; Smith, D.L. [Argonne National Lab., IL (United States)

    1998-03-01

    Subsize tensile and Charpy specimens made from several V-(4-5)Cr-(4-5)Ti alloys were irradiated in the ATR-A1 experiment to study the effects of low-temperature irradiation on mechanical properties. These specimens were contained in lithium-bonded subcapsules and irradiated at temperatures between {approx}200 and 300 C. Peak neutron damage was {approx}4.7 dpa. Postirradiation testing of these specimens has begun. Preliminary results from a limited number of specimens indicate a significant loss of work-hardening capability and dynamic toughness due to the irradiation. These results are consistent with data from previous low-temperature neutron irradiation experiments on these alloys.

  20. Defects involving interstitial boron in low-temperature irradiated silicon

    Science.gov (United States)

    Khirunenko, L. I.; Sosnin, M. G.; Duvanskii, A. V.; Abrosimov, N. V.; Riemann, H.

    2016-12-01

    Interstitial boron-related defects in silicon subjected to irradiation with 5 MeV electrons at a temperature of 80 K are investigated by Fourier-transform infrared absorption spectroscopy. This study demonstrates the radiation-enhanced annealing of interstitial boron during irradiation. We have revealed the interaction, which occurs in the course of irradiation, of diffusing interstitial boron atoms with one another and with interstitial oxygen. The local vibrational modes associated with these defects are identified, and the thermal stability of the defects is determined.

  1. Development of a sample environment for neutron diffraction at low temperature

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jeong Soo; Lee, Chang Hee; Choi, Yong Nam

    2000-06-01

    This report contains the development of low temperature sample environment for the neutron diffraction and its utilization techniques. With this research, a low temperature experimental facility of T=10-300 K was developed. We measured magnetic peak of La{sub 1}.4Sr{sub 1}.6Mn{sub 2}O{sub 7} due to low temperature phase transition successfully by this unit installed at the sample table of HRPD. Therefore, the research capability for various materials under the low temperature was expanded.

  2. Low Temperature Irradiation Embrittlement of Reactor Pressure Vessel Steels

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jy-An John [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-08-01

    The embrittlement trend curve development project for HFIR reactor pressure vessel (RPV) steels was carried out with three major tasks. Which are (1) data collection to match that used in HFIR steel embrittlement trend published in 1994 Journal Nuclear Material by Remec et. al, (2) new embrittlement data of A212B steel that are not included in earlier HFIR RPV trend curve, and (3) the adjustment of nil-ductility-transition temperature (NDTT) shift data with the consideration of the irradiation temperature effect. An updated HFIR RPV steel embrittlement trend curve was developed, as described below. NDTT( C) = 23.85 log(x) + 203.3 log (x) + 434.7, with 2- uncertainty of 34.6 C, where parameter x is referred to total dpa. The developed update HFIR RPV embrittlement trend curve has higher embrittlement rate compared to that of the trend curve developed in 1994.

  3. Effect of small additional elements on DBTT of V 4Cr 4Ti irradiated at low temperatures

    Science.gov (United States)

    Shibayama, Tamaki; Yamagata, Ichiro; Kayano, Hideo; Namba, Chusei

    1998-10-01

    As a part of a program to screen several V-4Cr-4Ti containing Si, Al and Y alloys and optimize the amounts of Si, Al and Y, the Charpy impact test of five kinds of V-4Cr-4Ti-Si-Al-Y alloys by an instrumented Charpy impact testing machine using miniaturized specimens (1.5 mm × 1.5 mm × 20 mm) have been conducted before and after neutron irradiation. Charpy impact specimens were encapsulated in an aluminum vial filled with high purity He and irradiated up to 1.06 × 10 19 n/cm 2 ( E > 1 MeV, 156 h) at low temperatures (about 150°C) in Japan Materials Testing Reactor (JMTR). The ductile brittle transition temperature (DBTT) of each alloy was determined by various methods on absorbed energy, brittle fracture ratio and lateral expansion from a quantitative analysis of fractography for broken specimens after the Charpy impact test. Almost all specimens were embrittled after low temperature irradiation. Decomposition of primary precipitates could result in migration of interstitial elements to irradiation defects and many precipitates are formed under irradiation. Radiation hardening then caused the substantial degradation of its fracture toughness.

  4. Thermoluminescence analysis of co-doped NaCl at low temperature irradiations

    Energy Technology Data Exchange (ETDEWEB)

    Cruz-Zaragoza, E., E-mail: ecruz@nucleares.unam.m [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, A.P. 70-543, 04510 Mexico D.F. (Mexico); Ortiz, A. [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, A.P. 70-543, 04510 Mexico D.F. (Mexico); Unidad Profesional Interdisciplinaria de Ingenieria y Tecnologias Avanzadas, IPN, Av. Instituto Politecnico Nacional 2580, Col. La Laguna Ticoman, 07340 Mexico D.F. (Mexico); Furetta, C. [Touro University Rome, Circne Gianicolense 15-17, 00153 Rome (Italy); Flores J, C.; Hernandez A, J.; Murrieta S, H. [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, A.P. 20-364, 01000 Mexico D.F. (Mexico)

    2011-02-15

    The thermoluminescent response and kinetics parameters of NaCl, doubly activated by Ca-Mn and Cd-Mn ions, exposed to gamma radiation are analyzed. The doped NaCl samples were irradiated at relative low temperature, i.e. at the liquid nitrogen temperature (LNT) and at dry ice temperature (DIT), and the glow curves obtained after 2 Gy of gamma irradiation were analyzed using the computerized glow curve deconvolution (CGCD). An evident variation in the glow curve structure after LNT and DIT was observed. It seems that different kinds of trapping levels are activated at relative low temperature. The original two prominent peaks in compositions A (Ca,Mn) and B (Ca,Mn) have been changed in only one main peak with satellites in the low temperature side of the glow curves. In compositions C (Cd,Mn) and D (Cd,Mn), low temperature peaks become stronger and prominent than the high temperature peaks; this effect could be explained considering that the trapping probability for low temperature traps, the one very close to the conduction band, is enhanced by low temperatures during irradiation.

  5. Effects of irradiation at low temperature on V-4Cr-4Ti

    Energy Technology Data Exchange (ETDEWEB)

    Alexander, D.J.; Snead, L.L.; Zinkle, S.J. [Oak Ridge National Lab., TN (United States)] [and others

    1996-10-01

    Irradiation at low temperatures (100 to 275{degrees}C) to 0.5 dpa causes significant embrittlement and changes in the subsequent room temperature tensile properties of V-4Cr-4Ti. The yield strength and microhardness at room temperature increase with increasing irradiation temperature. The tensile flow properties at room temperature show large increases in strength and a complete loss of work hardening capacity with no uniform ductility. Embrittlement, as measured by an increase in the ductile-to-brittle transition temperature, increases with increasing irradiation temperature, at least up to 275{degrees}C. This embrittlement is not due to pickup of O or other interstitial solutes during the irradiation.

  6. The influence of low temperature on gamma-ray irradiated permanent magnets.

    Science.gov (United States)

    Han, Young Chul; Cha, Hyun Gil; Kim, Chang Woo; Ji, Eun Sun; Kim, Young Hwan; Kang, Dong In; Kang, Young Soo

    2009-12-01

    The temperature effect on the magnetic property of gamma-ray irradiated Nd-Fe-B and Sr-Ferrite magnets has been investigated. When the permanent magnets are exposed to gamma-ray, it's magnetic and other related properties are declined with degree of dose. The decreased magnetic property by gamma-ray irradiation at low temperature is similar with the result of magnet at high temperature. The temperature effect on the gamma-ray irradiation at exposed moment is also regarded as one of the important parameters for the reduced magnetic properties. The gamma-irradiation at low temperature was carried out at 195 K, and the changed properties of two kinds of magnets before and after gamma-irradiation were comparatively studied. The increased demagnetization of the magnets were studied by Hall probe. And changed Curie temperature and micro-crystal structure of each permanent magnet by gamma-ray irradiation has been also studied. Moreover the strong and broad single line shape of ESR signal in the resonance magnetic field is attributed to unpaired electron of Fe2+ in the sample by the effect of gamma-ray irradiation.

  7. In Situ Irradiation and Measurement of Triple Junction Solar Cells at Low Intensity, Low Temperature (LILT) Conditions

    Science.gov (United States)

    Harris, R.D.; Imaizumi, M.; Walters, R.J.; Lorentzen, J.R.; Messenger, S.R.; Tischler, J.G.; Ohshima, T.; Sato, S.; Sharps, P.R.; Fatemi, N.S.

    2008-01-01

    The performance of triple junction InGaP/(In)GaAs/Ge space solar cells was studied following high energy electron irradiation at low temperature. Cell characterization was carried out in situ at the irradiation temperature while using low intensity illumination, and, as such, these conditions reflect those found for deep space, solar powered missions that are far from the sun. Cell characterization consisted of I-V measurements and quantum efficiency measurements. The low temperature irradiations caused substantial degradation that differs in some ways from that seen after room temperature irradiations. The short circuit current degrades more at low temperature while the open circuit voltage degrades more at room temperature. A room temperature anneal after the low temperature irradiation produced a substantial recovery in the degradation. Following irradiation at both temperatures and an extended room temperature anneal, quantum efficiency measurement suggests that the bulk of the remaining damage is in the (In)GaAs sub-cell

  8. In Situ Irradiation and Measurement of Triple Junction Solar Cells at Low Intensity, Low Temperature (LILT) Conditions

    Science.gov (United States)

    Harris, R.D.; Imaizumi, M.; Walters, R.J.; Lorentzen, J.R.; Messenger, S.R.; Tischler, J.G.; Ohshima, T.; Sato, S.; Sharps, P.R.; Fatemi, N.S.

    2008-01-01

    The performance of triple junction InGaP/(In)GaAs/Ge space solar cells was studied following high energy electron irradiation at low temperature. Cell characterization was carried out in situ at the irradiation temperature while using low intensity illumination, and, as such, these conditions reflect those found for deep space, solar powered missions that are far from the sun. Cell characterization consisted of I-V measurements and quantum efficiency measurements. The low temperature irradiations caused substantial degradation that differs in some ways from that seen after room temperature irradiations. The short circuit current degrades more at low temperature while the open circuit voltage degrades more at room temperature. A room temperature anneal after the low temperature irradiation produced a substantial recovery in the degradation. Following irradiation at both temperatures and an extended room temperature anneal, quantum efficiency measurement suggests that the bulk of the remaining damage is in the (In)GaAs sub-cell

  9. Neutron irradiation effects on plasma facing materials

    Science.gov (United States)

    Barabash, V.; Federici, G.; Rödig, M.; Snead, L. L.; Wu, C. H.

    2000-12-01

    This paper reviews the effects of neutron irradiation on thermal and mechanical properties and bulk tritium retention of armour materials (beryllium, tungsten and carbon). For each material, the main properties affected by neutron irradiation are described and the specific tests of neutron irradiated armour materials under thermal shock and disruption conditions are summarized. Based on current knowledge, the expected thermal and structural performance of neutron irradiated armour materials in the ITER plasma facing components are analysed.

  10. Structural behaviour of AgNO3 at low temperatures by neutron diffraction

    Indian Academy of Sciences (India)

    P U Sastry; P S R Krishna; Lata Panicker; A B Shinde

    2008-11-01

    Structural behaviour of silver nitrate (AgNO3) at low temperatures has been investigated by neutron powder diffraction and differential scanning calorimetry (DSC). Analysis showed abnormal changes in the rotations of nitrate (NO3) anions and thermal displacement parameters of the atoms near 220 K and 125 K. However, the basic lattice is compatible with the orthorhombic symmetry (space group Pbca) till 12 K. The fine, small-scale structural anomalies probably originate from freezing of reorientation of NO3 ions from high-temperature disordered phase.

  11. Damage structure of austenitic stainless steel 316LN irradiated at low temperature in HFIR

    Energy Technology Data Exchange (ETDEWEB)

    Hashimoto, N.; Robertson, J.P.; Grossbeck, M.L.; Rowcliffe, A.F. [Oak Ridge National Lab., TN (United States); Wakai, E. [Japan Atomic Energy Research Inst. (Japan)

    1998-03-01

    TEM disk specimens of austenitic stainless steel 316LN irradiated to damage levels of about 3 dpa at irradiation temperatures of either about 90 C or 250 C have been investigated by using transmission electron microscopy. The irradiation at 90 C and 250 C induced a dislocation loop density of 3.5 {times} 10{sup 22} m{sup {minus}3} and 6.5 {times} 10{sup 22} m{sup {minus}3}, a black dot density of 2.2 {times} 10{sup 23} m{sup {minus}3} and 1.6 {times} 10{sup 23} m{sup {minus}3}, respectively, in the steels, and a high density (<1 {times} 10{sup 22} m{sup {minus}3}) of precipitates in matrix. Cavities could be observed in the specimens after the irradiation. It is suggested that the dislocation loops, the black dots, and the precipitates cause irradiation hardening, an increase in the yield strength and a decrease in the uniform elongation, in the 316LN steel irradiated at low temperature.

  12. Neutrons from Antiproton Irradiation

    DEFF Research Database (Denmark)

    Bassler, Niels; Holzscheiter, Michael; Petersen, Jørgen B.B.

    Background: Radiotherapy with Antiprotons is currently investigated by the AD-4/ACE collaboration. The hypothesis is that the additional energy released from the antiprotons annihilating at the target nuclei can enable a reduced dose in the entry channel of the primary beam. Furthermore an enhanced...... relative biological effect (RBE) has already been beam measured in spread out Bragg peaks of antiprotons, relative to that found in the plateau region. However, the antiproton annihilation process is associated with a substantial release of secondary particles which contribute to the dose outside...... the neutron spectrum. Additionally, we used a cylindrical polystyrene loaded with several pairs of thermoluminescent detectors containing Lithium-6 and Lithium-7, which effectively detects thermalized neutrons. The obtained results are compared with FLUKA imulations. Results: The results obtained...

  13. Spin 1 centers in neutron irradiated silicon

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Wun; Newell, G. S.

    1963-03-01

    Electron paramagnetic resonance was used to identify a number of fast-neutron induced defects formed in pile irradiated Si and to follow their concentrations as a function of annealing. Measurements were made at 300, 77, and 4.2 deg K on samples that had attained intrinsic resistivity during irradiation, using superheterodyne spectrometers operating at 24 kMc and 9.4 kMc. Aside from the Si-N center, the most prominent lines of the spectrum arise from the m/sub s/ = O to plus or minus 1 transitions of four spin 1 systems. The distinct symmetry and small production rate ( approximately 0.05 centers per fast neutron collision) indicate a class of well-defined but relatively rare defects. Their g tensors, zero-field splitting tensors, and hfs are compatible with systems having two weakly interacting (1 1 1) dangling bonds separated by about a lattice spacing, giving the S = 1 Hamiltonians in the triplet levels formed by the weak exchange interaction. Low-temperature measurements suggest that the singlet-triplet splitting lies between 3 and 50 cm-1. Comparison with floating zone Si shows Center (11, 111), which is dominant in unannealed samples, to be independent of impurity. The remaining three S = 1 centers, which grow and decay rapidly at higher temperatures, involve O. Precise measurements of the parameters of the spin Hamiltonians are given to permit reproducible identification of the centers. (auth)

  14. Neutron diffraction studies of the low-temperature magnetic structure of hexagonal FeGe

    DEFF Research Database (Denmark)

    Bernhard, J.; Lebech, Bente; Beckman, O.

    1984-01-01

    The magnetic structure of the hexagonal polymorph of FeGe has been investigated by means of neutron diffraction on single crystals at low temperature and for magnetic fields applied perpendicular to the c axis. Between 410 and approximately 55K the magnetic structure is collinear c......-axis antiferromagnetic. Below approximately 55K the structure changes to c-axis double-cone antiferromagnetic with an inter-layer turn angle for the basal-plane moment component of 194.4 degrees , independent of temperature and applied field. The cone half-angle increases with decreasing temperature to approximately 14...... degrees at 4.2K, but its temperature dependence shows a pronounced kink at 30K, indicating a phase change at this temperature. At 4.2K the authors observe an anomalous decrease of the basal-plane moment component at a critical field (B perpendicular to c) of 1.4 T. As the temperature is increased...

  15. Mechanical-property changes of polymeric and composite materials after low-temperature proton irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Snead, C.L. Jr.; Czajkowski, C.J.; Skaritka, J. [Brookhaven National Lab., Upton, NY (United States). Dept. of Advanced Technology; Morena, J. [Ace Inc., Stuart, FL (United States)

    1999-02-01

    The mechanical properties of polymeric and composite materials are known to be sensitive to ionizing radiation. Most of the existing data, however, is the result of near-room-temperature irradiations, most commonly with {sup 60}Co gamma irradiation. For use of these materials in applications such as for magnetic fusion magnets, where operation will be at cryogenic temperatures in sometimes severe radiation fields, knowledge of the materials` radiation response to low-temperature irradiations is required. This paper reports the results of mechanical-property-change measurements made at 4.2K on a number of potential magnet materials following 200-MeV-proton irradiation at temperatures below 20K. Standard three-point bend tests were performed at 4.2K for short-beam shear determinations in the laminate materials and for shear strength in the remainder of the specimens. Specimens were warmed to room temperature for one week prior to the mechanical testing in order to emulate the expected the expected mechanical state of the material assuming room-temperature cycling in the expected magnet applications. Data are presented in the form of yield stresses before and after irradiations with percentages of change. There were five specimens per test dose for each material. Data are presented for exposures ranging from nominally 10{sup 7} to 10{sup 9} rad. Results of the mechanical tests range from complete delamination and distortion of the specimens at 10{sup 9} rad to an increase in the yield stress of 63% after 10{sup 9} rad. The latter specimen did, however, evidence significant embrittlement. The phenomenon of irradiation-induced strengthening due to enhanced cross linking in undercured polymers was observed in some cases.

  16. A theoretical model of accelerated irradiation creep at low temperatures by transient interstitial absorption

    Energy Technology Data Exchange (ETDEWEB)

    Stoller, R.E.; Grossbeck, M.L.; Mansur, L.K.

    1990-01-01

    A theoretical model has been developed using the reaction rate theory of radiation effects to explain experimental results that showed higher than expected values of irradiation creep at low temperatures in the Oak Ridge Research Reactor. The customary assumption that the point defect concentrations are at steady state was not made; rather, the time dependence of the vacancy and interstitial concentrations and the creep rate were explicitly calculated. For temperatures below about 100 to 200{degree}C, the time required for the vacancy concentration to reach steady state exceeds the duration of the experiment. For example, if materials parameters typical of austenitic stainless steel are used, the calculated vacancy transient dose at 100{degree}C is about 100 dpa. At 550{degree}C this transient is over by 10{sup {minus}8} dpa. During the time that the vacancy population remains lower than its steady state value, dislocation climb is increased since defects of primarily one type are being absorbed. Using the time-dependent point defect concentrations, the dislocation climb velocity has been calculated as a function of time and a climb-enabled glide creep model had been invoked. The extended transient time for the vacancies leads to high creep rates at low temperatures. In agreement with the experimental observations, a minimum in the temperature dependence of creep is predicted at a temperature between 50 and 350{degree}C. The temperature at which the minimum occurs decreases as the irradiation dose increases. Predicted values of creep at 8 dpa are in good agreement with the results of the ORR-MFE-6J/7J experiment.

  17. Low-temperature TCT characterization of heavily proton irradiated p-type magnetic Czochralski silicon detectors

    CERN Document Server

    Härkönen, J; Luukka, P; Kassamakov, I; Autioniemi, M; Tuominen, E; Sane, P; Pusa, P; Räisänen, J; Eremin, V; Verbitskaya, E; Li, Z

    2007-01-01

    n+/p−/p+ pad detectors processed at the Microelectronics Center of Helsinki University of Technology on boron-doped p-type high-resistivity magnetic Czochralski (MCz-Si) silicon substrates have been investigated by the transient current technique (TCT) measurements between 100 and 240 K. The detectors were irradiated by 9 MeV protons at the Accelerator Laboratory of University of Helsinki up to 1 MeV neutron equivalent fluence of 2×1015 n/cm2. In some of the detectors the thermal donors (TD) were introduced by intentional heat treatment at 430 °C. Hole trapping time constants and full depletion voltage values were extracted from the TCT data. We observed that hole trapping times in the order of 10 ns were found in heavily (above 1×1015 neq/cm2) irradiated samples. These detectors could be fully depleted below 500 V in the temperature range of 140–180 K.

  18. Low temperature neutron diffraction data for CeCo{sub 0.86}Ge{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Gil, A. [Department of Mathematics and Natural Sciences, Pedagogical University, Armii Krajowej 13/15, 42-800 Czestochowa (Poland); Penc, B. [M. Smoluchowski Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Crakow (Poland); Hernandez-Velasco, J. [Berlin Neutron Scattering Center, Hahn-Meitner Institute, Glienicker Str. 100, D-14109 Berlin Wannsee (Germany); Wawrzynska, E. [M. Smoluchowski Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Cracow (Poland); Szytula, A. [M. Smoluchowski Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Cracow (Poland)]. E-mail: szytula@if.uj.ed.pl

    2005-01-25

    Neutron diffraction measurements have been performed on CeCo{sub 0.86}Ge{sub 2} at low temperatures. The obtained data confirm that this compound crystallizes in the orthorhombic CeNiSi{sub 2}-type structure (space group Cmcm). Magnetic ordering is not detected at 1.5 K.

  19. Neutron scattering study of the excitation spectrum of solid helium at ultra-low temperatures

    Indian Academy of Sciences (India)

    Elizabeth Blackburn; John Goodkind; Sunil K Sinha; Collin Broholm; John Copley; Ross Erwin

    2008-10-01

    There has b3een a resurgence of interest in the properties of solid helium due to the recent discovery of non-classical rotational inertia (NCRI) in solid 4He by Chan and coworkers below 200 mK which they have interpreted as a transition to a `supersolid' phase. We have carried out a series of elastic and inelastic neutron scattering measurements on single crystals of hcp 4He at temperatures down to 60 mK. While we have found no direct evidence of any change in the excitation spectrum at low temperatures, we have found that the excitation spectrum of solid 4He shows several interesting features, including extra branches in addition to the phonon branches. We interpret these extra branches as single particle excitations due to propagating vacancy waves, which map on to the famous `roton minimum' long known in the excitation spectrum of superfluid liquid 4He. The results show that in fact solid 4He shares several features in common with the superfluid.

  20. Response of Bacillus subtilis spores to dehydration and UV irradiation at extremely low temperatures.

    Science.gov (United States)

    Dose, K; Klein, A

    1996-02-01

    Spores of Bacillus subtilis have been exposed to the conditions of extreme dehydration (argon/silica gel; simulated space vacuum) for up to 12 weeks at 298 K and 80 K in the dark. The inactivation has been correlated with the production of DNA-double strand-breaks. The temperature-dependence of the rate constants for inactivation or production of DNA-double strand-breaks is surprisingly low. Controls kept in the frozen state at 250 K for the same period of time showed no sign of deterioration. In another series of experiments the spores have been UV irradiated (253.7 nm) at 298 K, 200 K and 80 K after exposure to dehydrating conditions for 3 days. Fluence-effect relationships for inactivation, production of DNA-double strand-breaks and DNA-protein cross-links are presented. The corresponding F37-values for inactivation and production of DNA lesions are significantly increased only at 80 K (factor of 4 to 5). The data indicate that the low temperatures that prevail in the outer parts of the Solar System or at the nightside of Mars or the Moon are not sufficiently low to crucially inhibit inactivation by dehydration. Our data place further constraints on the panspermia hypothesis.

  1. GENOTYPIC VARIATION IN CHLOROPHYLL FLUORESCENCE PARAMETERS, PHOTOSYNTHESIS AND GROWTH OF TOMATO GROWN AT LOW-TEMPERATURE AND LOW IRRADIANCE

    NARCIS (Netherlands)

    JANSSEN, LHJ; VANOEVEREN, JC; VANHASSELT, PR; KUIPER, PJC

    1995-01-01

    The genetic variation in low temperature sensitivity of eight tomato genotypes grown at suboptimal temperature (19 degrees C) and at low irradiance (140 mu mol m(-2) s(-1)) was assessed at the plant, chloroplast and thylakoid membrane levels. Temperature effects on the thylakoid membrane were determ

  2. Accelerated oxygen precipitation in fast neutron irradiated Czochralski silicon

    Institute of Scientific and Technical Information of China (English)

    Ma Qiao-Yun; Li Yang-Xian; Chen Gui-Feng; Yang Shuai; Liu Li-Li; Niu Ping-Juan; Chen Dong-Feng; Li Hong-Tao

    2005-01-01

    Annealing effect of the oxygen precipitation and the induced defects have been investigated on the fast neutron irradiated Czochralski silicon (CZ-Si) by infrared absorption spectrum and the optical microscopy. It is found that the fast neutron irradiation greatly accelerates the oxygen precipitation that leads to a sharp decrease of the interstitial oxygen with the annealing time. At room temperature (RT), the 1107cm-1 infrared absorption band of interstitial oxygen becomes weak and broadens to low energy side. At low temperature, the infrared absorption peaks appear at 1078cm-1, 1096cm-1, and 1182cm-1, related to different shapes of the oxygen precipitates. The bulk microdefects,including stacking faults, dislocations and dislocation loops, were observed by the optical microscopy. New or large stacking faults grow up when the silicon self-interstitial atoms are created and aggregate with oxygen precipitation.

  3. Low-temperature neutron diffraction study of La0.95Nd0.05CrO3

    Indian Academy of Sciences (India)

    Keka R Chakraborty; S M Yusuf; P S R Krishna; M Ramanadham; A K Tyagi

    2004-08-01

    We have synthesized polycrystalline La0.95Nd0.05CrO3 sample by doping the La-site of LaCrO3 with Nd and its magnetic properties have been studied using DC magnetization and neutron diffraction techniques. DC magnetization study shows a paramagnetic to a weak ferromagnetic-like transition at ∼295 K followed by signatures of a spin reorientation phenomenon at 233 and 166 K and, finally a transition to an antiferromagnetic like phase at ∼ 21 K. Low-temperature neutron diffraction measurements confirm a weak ferrimagnetic ordering of Cr3+ moments at all temperatures below 295 K.

  4. New facility for post irradiation examination of neutron irradiated beryllium

    Energy Technology Data Exchange (ETDEWEB)

    Ishitsuka, Etsuo; Kawamura, Hiroshi [Oarai Research Establishment, Ibaraki-Ken (Japan)

    1995-09-01

    Beryllium is expected as a neutron multiplier and plasma facing materials in the fusion reactor, and the neutron irradiation data on properties of beryllium up to 800{degrees}C need for the engineering design. The acquisition of data on the tritium behavior, swelling, thermal and mechanical properties are first priority in ITER design. Facility for the post irradiation examination of neutron irradiated beryllium was constructed in the hot laboratory of Japan Materials Testing Reactor to get the engineering design data mentioned above. This facility consist of the four glove boxes, dry air supplier, tritium monitoring and removal system, storage box of neutron irradiated samples. Beryllium handling are restricted by the amount of tritium;7.4 GBq/day and {sup 60}Co;7.4 MBq/day.

  5. Design aspects of a cold neutron irradiator

    Energy Technology Data Exchange (ETDEWEB)

    Atwood, A.G.; Clark, D.D.; Hossain, T.Z.; Spern, S.A. [Cornell Univ., Ithaca, NY (United States)

    1995-12-31

    Design work on a cold-neutron irradiator (CNI) is being pursued at Cornell University. Prompt gamma neutron activation analysis (PGNAA) by means of cold neutron absorption is the objective of the CNI. Using cold neutrons instead of thermal neutrons to cause neutron capture in the sample, the CNI is a logical extension of the concept of a thermal neutron irradiator. Since the neutron capture cross section for most nuclei varies as 1/v, augmentation of the neutron capture reaction rate is achieved in the sample by a factor of {approximately}2.3. The statistical precision with which one can measure the mass of a particular element in the sample is enhanced in a CNI, in comparison with a thermal neutron irradiator, by a factor of between 2.3 and the square of 2.3. The exact factor by which the statistical precision is enhanced depends on the energy of the PGNAA photopeak at which one is looking and on the extent to which the photon background measured by the photon detector is dominated by either the {sup 252}Cf spontaneous fission photons or by the neutron capture photons from the CNI structural materials. Within the context of the optimization of the elemental sensitivity of the CNI system, the CNI must efficiently deliver cold neutrons from the {sup 252}Cf fast neutron source to the sample and must efficiently deliver the PGNAA gamma rays of the sample to the high-purity germanium (HPGe) photon detector while maintaining reasonable fast neutron and gamma-ray backgrounds at the detector.

  6. Low Temperature and Neutron Physics Studies: Final Progress Report, March 1, 1986--May 31, 1987

    Science.gov (United States)

    Shull, C.G.

    1989-07-27

    A search for a novel coupling interaction between the Pendelloesung periodicity which is formed in a diffracting crystal and the Larmor precession of neutrons in a magnetic field has been carried out. This interaction is expected to exhibit a resonant behavior when the two spatial periodicities become matched upon scanning the magnetic field being applied to the crystal. Observations on a diffracting, perfect crystal of silicon with neutrons of wavelength 1 Angstrom show the expected resonant action but some discrepancy between the observed magnitude of the resonance effects remains for interpretation.

  7. ATF Neutron Irradiation Program Irradiation Vehicle Design Concepts

    Energy Technology Data Exchange (ETDEWEB)

    Geringer, J. W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division; Katoh, Yutai [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division; Howard, Richard H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division; Cetiner, N. O. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division; Petrie, Christian M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division; Smith, Kurt R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division; McDuffee, J. M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division

    2016-03-01

    The Japan Atomic Energy Agency (JAEA) under the Civil Nuclear Energy Working Group (CNWG) is engaged in a cooperative research effort with the U.S. Department of Energy (DOE) to explore issues related to nuclear energy, including research on accident-tolerant fuels and materials for use in light water reactors. This work develops a draft technical plan for a neutron irradiation program on the candidate accident-tolerant fuel cladding materials and elements using the High Flux Isotope Reactor (HFIR). The research program requires the design of a detailed experiment, development of test vehicles, irradiation of test specimens, possible post irradiation examination and characterization of irradiated materials and the shipment of irradiated materials to Japan. This report discusses the conceptual design, the development and irradiation of the test vehicles.

  8. Irradiation embrittlement of neutron-irradiated ferritic steel

    Science.gov (United States)

    Kayano, H.; Narui, M.; Ohta, S.; Morozumi, S.

    1985-08-01

    In this study three kinds of Fe-Cr ferritic steels were examined by the instrumented Charpy test and tensile test before and after JMTR irradiation ( 2.2×10 23 f.n./m 2). In the unirradiated samples, 100%-martensite 5Cr-2Mo steel showed the highest adsorbed energy and the highest toughness at low temperatures, follewed by the 9Cr-2Mo steel, and the 20%-martensite 5Cr-2Mo steel showed the third highest toughness. In the irradiated samples, however, thoughness was low as a whole, especially in 20%-martensite 5Cr-2Mo steel. It was clarified that 100%-martensite 5Cr-2Mo steel had the lowest Ductile-to-Brittle Transition Temperature (DBTT) and the highest fracture toughness, and that its DBTT and fracture toughness changed a little upon irradiation, showing excellent irradiation characteristics. The general equations were considered for correlation among strength, ductillity, DBTT and fracture toughness ( J value)

  9. Microstructural analysis of ferritic-martensitic steels irradiated at low temperature in HFIR

    Energy Technology Data Exchange (ETDEWEB)

    Hashimoto, N.; Robertson, J.P.; Rowcliffe, A.F. [Oak Ridge National Lab., TN (United States); Wakai, E. [Japan Atomic Energy Research Inst. (Japan)

    1998-09-01

    Disk specimens of ferritic-martensitic steel, HT9 and F82H, irradiated to damage levels of {approximately}3 dpa at irradiation temperatures of either {approximately}90 C or {approximately}250 C have been investigated by using transmission electron microscopy. Before irradiation, tempered HT9 contained only M{sub 23}C{sub 6} carbide. Irradiation at 90 C and 250 C induced a dislocation loop density of 1 {times} 10{sup 22} m{sup {minus}3} and 8 {times} 10{sup 21} m{sup {minus}3}, respectively. in the HT9 irradiated at 250 C, a radiation-induced phase, tentatively identified as {alpha}{prime}, was observed with a number density of less than 1 {times} 10{sup 20} m{sup {minus}3}. On the other hand, the tempered F82H contained M{sub 23}C{sub 6} and a few MC carbides; irradiation at 250 C to 3 dpa caused minor changes in these precipitates and induced a dislocation loop density of 2 {times} 10{sup 22} m{sup {minus}3}. Difference in the radiation-induced phase and the loop microstructure may be related to differences in the post-yield deformation behavior of the two steels.

  10. Embrittlement behavior of neutron irradiated RAFM steels

    Energy Technology Data Exchange (ETDEWEB)

    Gaganidze, E. [Forschungszentrum Karlsruhe, Institut fuer Materialforschung II, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen (Germany)]. E-mail: ermile.gaganidze@imf.fzk.de; Schneider, H.-C. [Forschungszentrum Karlsruhe, Institut fuer Materialforschung II, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen (Germany); Dafferner, B. [Forschungszentrum Karlsruhe, Institut fuer Materialforschung II, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen (Germany); Aktaa, J. [Forschungszentrum Karlsruhe, Institut fuer Materialforschung II, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen (Germany)

    2007-08-01

    The effects of neutron irradiation on the embrittlement behavior of reduced activation ferritic/martensitic (RAFM) steel EUROFER97 for different heat treatment conditions have been investigated. The irradiation to 16.3 dpa at different irradiation temperatures (250-450 {sup o}C) was carried out in the Petten High Flux Reactor in the framework of the HFR Phase-IIb (SPICE) irradiation project. Several reference RAFM steels (F82H-mod, OPTIFER-Ia, GA3X) and MANET-I were also irradiated at selected temperatures. The embrittlement behavior and hardening were investigated by instrumented Charpy-V tests with subsize specimens. The neutron irradiation induced embrittlement and hardening of as-delivered EUROFER97 are comparable to those of investigated reference steels, being mostly pronounced for 250 {sup o}C and 300 {sup o}C irradiation temperatures. Heat treatment of EUROFER97 at higher austenization temperature substantially improves the embrittlement behavior at irradiation temperatures of 250 {sup o}C and 350 {sup o}C.

  11. Embrittlement behavior of neutron irradiated RAFM steels

    Science.gov (United States)

    Gaganidze, E.; Schneider, H.-C.; Dafferner, B.; Aktaa, J.

    2007-08-01

    The effects of neutron irradiation on the embrittlement behavior of reduced activation ferritic/martensitic (RAFM) steel EUROFER97 for different heat treatment conditions have been investigated. The irradiation to 16.3 dpa at different irradiation temperatures (250-450 °C) was carried out in the Petten High Flux Reactor in the framework of the HFR Phase-IIb (SPICE) irradiation project. Several reference RAFM steels (F82H-mod, OPTIFER-Ia, GA3X) and MANET-I were also irradiated at selected temperatures. The embrittlement behavior and hardening were investigated by instrumented Charpy-V tests with subsize specimens. The neutron irradiation induced embrittlement and hardening of as-delivered EUROFER97 are comparable to those of investigated reference steels, being mostly pronounced for 250 °C and 300 °C irradiation temperatures. Heat treatment of EUROFER97 at higher austenization temperature substantially improves the embrittlement behavior at irradiation temperatures of 250 °C and 350 °C.

  12. Low-temperature formation of high-quality gate oxide by ultraviolet irradiation on spin-on-glass

    Science.gov (United States)

    Usuda, R.; Uchida, K.; Nozaki, S.

    2015-11-01

    Although a UV cure was found to effectively convert a perhydropolysilazane (PHPS) spin-on-glass film into a dense SiOx film at low temperature, the electrical characteristics were never reported in order to recommend the use of PHPS as a gate-oxide material that can be formed at low temperature. We have formed a high-quality gate oxide by UV irradiation on the PHPS film, and obtained an interface midgap trap density of 3.4 × 1011 cm-2 eV-1 by the UV wet oxidation and UV post-metallization annealing (PMA), at a temperature as low as 160 °C. In contrast to the UV irradiation using short-wavelength UV light, which is well known to enhance oxidation by the production of the excited states of oxygen, the UV irradiation was carried out using longer-wavelength UV light from a metal halide lamp. The UV irradiation during the wet oxidation of the PHPS film generates electron-hole pairs. The electrons ionize the H2O molecules and facilitate dissociation of the molecules into H and OH-. The OH- ions are highly reactive with Si and improve the stoichiometry of the oxide. The UV irradiation during the PMA excites the electrons from the accumulation layer, and the built-in electric field makes the electron injection into the oxide much easier. The electrons injected into the oxide recombine with the trapped holes, which have caused a large negative flat band voltage shift after the UV wet oxidation, and also ionize the H2O molecules. The ionization results in the electron stimulated dissociation of H2O molecules and the decreased interface trap density.

  13. On-line DLTS investigations of vacancy related defects in low-temperature electron irradiated, boron-doped Si

    Science.gov (United States)

    Zangenberg, N. R.; Nylandsted Larsen, A.

    2005-02-01

    Vacancy-related defects in Si are explored with deep level transient spectroscopy (DLTS). The measurements are performed on-line on irradiated p-type Si and a new trap with the signature (Epa, σpa) = (0.18 eV, 6.5×10-15 cm2) only present at cryogenic temperatures is studied. Furthermore, the bi-stable boron-vacancy complex is studied and it’s configuration at low temperatures is investigated and found to have the signature (Epa, σpa) = (0.11 eV, 8.2×10-15 cm2).

  14. Dislocation morphology in deformed and irradiated niobium. [Neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Chang, C. P.

    1977-06-01

    Niobium foils of moderate purity were examined for the morphology of dislocations or defect clusters in the deformed or neutron-irradiated state by transmission electron microscopy. New evidence has been found for the dissociation of screw dislocations into partials on the (211) slip plane according to the Crussard mechanism: (a/2) (111) ..-->.. (a/3) (111) + (a/6) (111).

  15. Investigation of an unusual low-temperature phase transformation in RbBH{sub 4} by neutron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Kitchen, Brian B. [Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI 48109 (United States); Verdal, Nina, E-mail: nina.verdal@nist.gov [NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899-6102 (United States); Department of Materials Science and Engineering, University of Maryland, College Park, MD 20742-2115 (United States); Udovic, Terrence J. [NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899-6102 (United States); Rush, John J. [NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899-6102 (United States); Department of Materials Science and Engineering, University of Maryland, College Park, MD 20742-2115 (United States); Hartman, Michael R. [Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI 48109 (United States); DeVries, Daniel J. [Radiation and Isotopes for Health, Delft University of Technology, Mekelweg 15, 2629 JB Delft (Netherlands)

    2013-07-15

    To investigate the previously reported low-temperature phase transition in rubidium borohydride (RbBH{sub 4}) near 48.5 K, we carried out neutron powder diffraction and vibrational spectroscopy measurements both above and below this temperature on an isotopically-enriched sample of Rb{sup 11}BD{sub 4}. Our diffraction data reflected an average cubic Fm3{sup ¯}m structure with BD{sub 4}{sup −} anion orientational disorder at all temperatures, with no hint of extra Bragg peaks due to long-range orientational order below the transition temperature as reported by others. These structural results and careful analysis of torsional vibrations in RbBD{sub 4} corroborate the results of prior neutron vibrational spectroscopy measurements suggesting that the low-temperature RbBH{sub 4} structure indeed possesses some orientational ordering of the BH{sub 4}{sup −} anions, but of a shorter-ranged nature insensitive to powder diffraction methods. - The neutron powder diffraction pattern of RbBD{sub 4} below the phase transition temperature (shown here in black) is indistinguishable from that collected above the phase transition temperature. The inset depicts the cubic structure that fits the data at both temperatures. - Highlights: • We investigated the nature of the RbBD{sub 4} phase transition using NVS and NPD. • A change in shape of the RbBD{sub 4} torsion mode was observed across the transition. • The RbBD{sub 4} diffraction pattern across this phase transition was unchanged. • The phase transition in RbBD{sub 4} appears to produce only short-range ordering of BD{sub 4}{sup −}.

  16. Polyethylene terephthalate degradation under reactor neutron irradiation

    Science.gov (United States)

    Chikaoui, K.; Izerrouken, M.; Djebara, M.; Abdesselam, M.

    2017-01-01

    This paper is devoted to study the defects generated by reactor neutron in polyethylene terephthalate (PET) films. The explored fast neutron fluence ranges from 2.02×1016 to 2.07×1018 n cm-2. The induced damages were investigated using ultraviolet-visible spectrophotometry (UV-vis), Fourier Transform Infrared spectrometry (FTIR) and X-ray diffraction (XRD). The UV-vis spectra show important changes indicating the degradation of the chemical structure and the creation of new chromophores. FTIR spectra reveal that the intensities of the different absorption bands decrease linearly under fast neutron irradiation. The internal reference band at 1410 cm-1 is used to follow the overall damage during irradiation. The 1342 cm-1 band corresponding to CH2 wagging of trans conformation of crystalline phase show a sharpe linear decrease as the fast neutrons fluence goes up. The creation of the monosubstituted benzene, investigated using the 1610 cm-1 band. It shows a linear increase with fast neutron fluence. It is found from XRD analysis that the diffraction peak (100) intensity is drastically reduced after irradiation at 2.02×1016 n cm-2.

  17. Thermal annealing in neutron-irradiated tribromobenzenes

    DEFF Research Database (Denmark)

    Siekierska, K.E.; Halpern, A.; Maddock, A. G.

    1968-01-01

    The distribution of 82Br among various products in neutron-irradiated isomers of tribromobenzene has been investigated, and the effect of thermal annealing examined. Reversed-phase partition chromatography was employed for the determination of radioactive organic products, and atomic bromine...

  18. Low-temperature positron-lifetime studies of proton-irradiated silicon

    DEFF Research Database (Denmark)

    Mäkinen, S.; Rajainmäki, H.; Linderoth, Søren

    1990-01-01

    The positron-lifetime technique has been used to identify defects created in high-purity single-crystal silicon by irradiation with 12-MeV protons at 15 K, and the evolution of the defects has been studied by subsequent annealings between 20 and 650 K. Two clear annealing steps were seen in the s......The positron-lifetime technique has been used to identify defects created in high-purity single-crystal silicon by irradiation with 12-MeV protons at 15 K, and the evolution of the defects has been studied by subsequent annealings between 20 and 650 K. Two clear annealing steps were seen...

  19. Neutron irradiation induced amorphization of silicon carbide

    Energy Technology Data Exchange (ETDEWEB)

    Snead, L.L.; Hay, J.C. [Oak Ridge National Lab., TN (United States)

    1998-09-01

    This paper provides the first known observation of silicon carbide fully amorphized under neutron irradiation. Both high purity single crystal hcp and high purity, highly faulted (cubic) chemically vapor deposited (CVD) SiC were irradiated at approximately 60 C to a total fast neutron fluence of 2.6 {times} 10{sup 25} n/m{sup 2}. Amorphization was seen in both materials, as evidenced by TEM, electron diffraction, and x-ray diffraction techniques. Physical properties for the amorphized single crystal material are reported including large changes in density ({minus}10.8%), elastic modulus as measured using a nanoindentation technique ({minus}45%), hardness as measured by nanoindentation ({minus}45%), and standard Vickers hardness ({minus}24%). Similar property changes are observed for the critical temperature for amorphization at this neutron dose and flux, above which amorphization is not possible, is estimated to be greater than 130 C.

  20. Using Neutron Diffraction to Determine the Low-Temperature Behavior of Pb2+ in Lead Feldspar

    Science.gov (United States)

    Kolbus, L. M.; Anovitz, L. M.; Chakoumackos, B. C.; Wesolowski, D. J.

    2014-12-01

    Feldspar minerals comprise 60% of the Earth's crust, so it imperative that the properties of feldspar be well understood for seismic modeling. The structure of feldspar consists of a three-dimensional framework of strongly-bonded TO4 tetrahedra formed by the sharing of oxygen atoms between tetrahedra. The main solid solution series found in natural feldspars are alkali NaAlSi3O8 -KAlSi3O8 and plagioclase CaAl2Si2O8-NaAlSi3O8. Recently, efforts have been made to systematically quantify feldspars structural change at non-ambient temperatures by considering only the relative tilts of the tetrahedral framework [1]. This serves as a tool to predict various behaviors of the structure such as the relative anisotropy of unit cell parameters and volume evolution with composition and temperature. Monoclinic feldspars are well predicted by the model [1], but discrepancies still remain between the model predictions and real structures with respect to absolute values of the unit cell parameters. To improve the existing model, a modification must be made to account for the M-cation interaction with its surrounding oxygen atoms. We have, therefore, chosen to study the structure of Pb-feldspar (PbAl2Si2O8), which provides the opportunity to characterize a monoclinic Al2Si2 feldspar containing a large M-site divalent cation using neutron diffraction. Neutron diffraction allows for the characterization of the M-site cation interaction between the oxygen atoms in the polyhedral cage by providing information to accurately determine the atomic displacement parameters.. Lead feldspar was synthesized for this study using the method described in [2], and confirmed to have a monoclinic C2/m space group. In this talk we will present structural determinations and atomic displacement parameters of Pb-feldspar from 10 - 300K generated from Neutron diffraction at the POWGEN beamline at the Spallation Neutron Source at Oak Ridge National lab, and compare our results to those predicted by the

  1. Low-temperature irradiation behavior of uranium-molybdenum alloy dispersion fuel

    Science.gov (United States)

    Meyer, M. K.; Hofman, G. L.; Hayes, S. L.; Clark, C. R.; Wiencek, T. C.; Snelgrove, J. L.; Strain, R. V.; Kim, K.-H.

    2002-08-01

    Irradiation tests have been conducted to evaluate the performance of a series of high-density uranium-molybdenum (U-Mo) alloy, aluminum matrix dispersion fuels. Fuel plates incorporating alloys with molybdenum content in the range of 4-10 wt% were tested. Two irradiation test vehicles were used to irradiate low-enrichment fuels to approximately 40 and 70 at.% 235U burnup in the advanced test reactor at fuel temperatures of approximately 65 °C. The fuel particles used to fabricate dispersion specimens for most of the test were produced by generating filings from a cast rod. In general, fuels with molybdenum contents of 6 wt% or more showed stable in-reactor fission gas behavior, exhibiting a distribution of small, stable gas bubbles. Fuel particle swelling was moderate and decreased with increasing alloy content. Fuel particles with a molybdenum content of 4 wt% performed poorly, exhibiting extensive fuel-matrix interaction and the growth of relatively large fission gas bubbles. Fuel particles with 4 or 6 wt% molybdenum reacted more rapidly with the aluminum matrix than those with higher-alloy content. Fuel particles produced by an atomization process were also included in the test to determine the effect of fuel particle morphology and microstructure on fuel performance for the U-10Mo composition. Both of the U-10Mo fuel particle types exhibited good irradiation performance, but showed visible differences in fission gas bubble nucleation and growth behavior.

  2. ATF Neutron Irradiation Program Technical Plan

    Energy Technology Data Exchange (ETDEWEB)

    Geringer, J. W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division; Katoh, Yutai [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division

    2016-03-01

    The Japan Atomic Energy Agency (JAEA) under the Civil Nuclear Energy Working Group (CNWG) is engaged in a cooperative research effort with the U.S. Department of Energy (DOE) to explore issues related to nuclear energy, including research on accident-tolerant fuels and materials for use in light water reactors. This work develops a draft technical plan for a neutron irradiation program on the candidate accident-tolerant fuel cladding materials and elements using the High Flux Isotope Reactor (HFIR). The research program requires the design of a detailed experiment, development of test vehicles, irradiation of test specimens, possible post irradiation examination and characterization of irradiated materials and the shipment of irradiated materials to JAEA in Japan. This report discusses the technical plan of the experimental study.

  3. ATF Neutron Irradiation Program Technical Plan

    Energy Technology Data Exchange (ETDEWEB)

    Geringer, J. W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division; Katoh, Yutai [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division

    2016-03-01

    The Japan Atomic Energy Agency (JAEA) under the Civil Nuclear Energy Working Group (CNWG) is engaged in a cooperative research effort with the U.S. Department of Energy (DOE) to explore issues related to nuclear energy, including research on accident-tolerant fuels and materials for use in light water reactors. This work develops a draft technical plan for a neutron irradiation program on the candidate accident-tolerant fuel cladding materials and elements using the High Flux Isotope Reactor (HFIR). The research program requires the design of a detailed experiment, development of test vehicles, irradiation of test specimens, possible post-irradiation examination and characterization of irradiated materials and the shipment of irradiated materials to JAEA in Japan. This report discusses the technical plan of the experimental study.

  4. Neutron irradiation of beryllium pebbles

    Energy Technology Data Exchange (ETDEWEB)

    Gelles, D.S.; Ermi, R.M. [Pacific Northwest National Lab., Richland, WA (United States); Tsai, H. [Argonne National Lab., IL (United States)

    1998-03-01

    Seven subcapsules from the FFTF/MOTA 2B irradiation experiment containing 97 or 100% dense sintered beryllium cylindrical specimens in depleted lithium have been opened and the specimens retrieved for postirradiation examination. Irradiation conditions included 370 C to 1.6 {times} 10{sup 22} n/cm{sup 2}, 425 C to 4.8 {times} 10{sup 22} n/cm{sup 2}, and 550 C to 5.0 {times} 10{sup 22} n/cm{sup 2}. TEM specimens contained in these capsules were also retrieved, but many were broken. Density measurements of the cylindrical specimens showed as much as 1.59% swelling following irradiation at 500 C in 100% dense beryllium. Beryllium at 97% density generally gave slightly lower swelling values.

  5. Difference of Low Temperature and Low Irradiance-Resistance between Figleaf Gourd and Cucumber Seedlings Related to Mineral Elements Uptake

    Institute of Scientific and Technical Information of China (English)

    LI Jian-Yong; GUO Shang-Jing; LI Xin-Guo; MENG Jing-Jinga; HE Qi-Wei

    2009-01-01

    We have repotted that the roots of fig, leaf gourd (Cucurbita ficifolia, as rootstock) could improve the resistance of cucumber seedlings (Cucumis sativus L.cv. Jinyan 4, as scion) to 6 h stress at low temperature and low irradiance [1]. In this experiment, the relationship between the mineral elements uptake and photosynthetic activity of photosystems in figleaf gourd and cucumber seedlings were to be studied during low temperature (8 C) stress under low irradiance (100 μ. mol m-2 s-1 PFD) for 5 days. Compared with control seedlings, the maximal photochemical efficiency of PS2 (Fv/Fm) and the oxidizable P700 (P700+) of both figleaf gourd and cucumber seedlings decreased, and beth Fv/Fm and P700+ were lower in cucumber leaves than in figleaf gourd seedlings at the end of the stress. Superoxide dismutase (SOD) activity was higher in beth leaves and roots of figleaf gourd than in leaves and roots of cucumber at both room temperature and low temperature. However, the product rate of O 2 was lower in figleaf gourd leaves than in cucumber leaves. Upon ex-posure to the stress, the malondialdehyde (MDA) content increased markedly in leaves and roots of figleaf gourd and cucumber seedlings, and it grew faster in cucumber seedlings than that in figleaf gourd seedlings. Under adaptive conditions, some mineral elements (Such as Cu, Zn, Mn and Mg) have different contents in leaves and roots between figleaf gourd seedlings and cucumber seedlings. However, at the end of the stress these elements were accumulated apparently in both leaves and roots of figleaf gourd accompanied by no obvious change in cucumber seedlings.

  6. Refined model of the {Fe9} magnetic molecule from low-temperature inelastic neutron scattering studies

    Energy Technology Data Exchange (ETDEWEB)

    Engelhardt, Larry [Francis Marion University; Demmel, Franz [Rutherford Appleton Laboratory; Luban, Marshall [Ames Laboratory; Timco, Grigore A [The University of Manchester; Tuna, Floriana [The University of Manchester; Winpenny, Richard E [The University of Manchester

    2014-06-01

    We present a refined model of the {Fe9} tridiminished icosahedron magnetic molecule system. This molecule was originally modeled as being composed of two ({Fe3} and {Fe6}) clusters, with the Fe3+ ions within each cluster being coupled via exchange interactions, but with no coupling between the clusters. The present inelastic neutron scattering (INS) measurements were used to probe the low-lying energy spectrum of {Fe9}, and these results demonstrate that the previously published model of two uncoupled clusters is incomplete. To achieve agreement between the experiment and theory, we have augmented the model with relatively small exchange coupling between the clusters. A combination of Lanczos matrix diagonalization and quantum Monte Carlo simulations have been used to achieve good agreement between the experimental data and the improved model of the full {Fe9} system despite the complexity of this model (with Hilbert space dimension >107).

  7. Neutron diffraction study of Li4Ti5O12 at low temperatures

    Science.gov (United States)

    Dolotko, Oleksandr; Senyshyn, Anatoliy; Mühlbauer, Martin J.; Boysen, Hans; Monchak, Mykhailo; Ehrenberg, Helmut

    2014-10-01

    The crystal structure of the "zero-strain" positive electrode material Li4Ti5O12 was characterized by neutron powder diffraction in the temperature range 3.4 K-300 K. No phase transition was detected, and the thermal evolution of lattice parameters has been evaluated by the 2nd order Grüneisen approximation using the Debye formalism for internal energy and intrinsic anharmonicity contributions. A relatively high Debye temperature θD = 689 ± 71 K was determined. The thermal behavior of cation-anion bond lengths in octahedral and tetrahedral environments is discussed. The lithium diffusion pathway in Li4Ti5O12 was discussed on the basis of bond-valence modeling.

  8. Vibronic photoexcitation spectra of irradiated spinel MgO·nAl{sub 2}O{sub 3} (n = 2) at low temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Rahman, Abu Zayed Mohammad Saliqur, E-mail: zayed82000@yahoo.com [Key Laboratory of Nuclear Analytical Techniques, Institute of High Energy Physics, Chinese Academy of Sciences, 19B Yuquanlu, Shijingshan District, Beijing 100049 (China); Cao, Xingzhong, E-mail: caoxzh@ihep.ac.cn [Key Laboratory of Nuclear Analytical Techniques, Institute of High Energy Physics, Chinese Academy of Sciences, 19B Yuquanlu, Shijingshan District, Beijing 100049 (China); Wei, Long, E-mail: weil@ihep.ac.cn [Key Laboratory of Nuclear Analytical Techniques, Institute of High Energy Physics, Chinese Academy of Sciences, 19B Yuquanlu, Shijingshan District, Beijing 100049 (China); Wang, Baoyi [Key Laboratory of Nuclear Analytical Techniques, Institute of High Energy Physics, Chinese Academy of Sciences, 19B Yuquanlu, Shijingshan District, Beijing 100049 (China); Tao, Ye [Beijing Synchrotron Radiation Facilities, Institute of High Energy Physics, Chinese Academy of Sciences, 19B Yuquanlu, Shijingshan District, Beijing 100049 (China); Xu, Qiu [Reactor Research Institute, Kyoto University, 2, Asashiro-Nishi, Kumatori-cho, Sennan-gun, Osaka 590-0494 (Japan); Atobe, Kozo [Nuclear Safety Technology Center, 9-15, 1-Chome, Utsubohonmachi, Nishi Ku, Osaka 550-0004 (Japan)

    2013-06-15

    Highlights: •Vibronic photoexcitation band at 230 nm was observed in irradiated spinel at low temperatures for the first time. •Vibronic photoexcitation band shows temperature dependence and becomes obscure at over 120 K. •Huang–Rhys factor S=2.78 and Debye temperature, 518 K were estimated from temperature dependence of 230 nm vibronic band. •Defect related Debye temperature was found to be lower than normal mode in MgO · nAl{sub 2}O{sub 3}(n = 2). -- Abstract: A vibronic photoexcitation band at approximately 230 nm was found at 13 K in reactor neutron- and electron-irradiated magnesium aluminate spinel (MgO · nAl{sub 2}O{sub 3}). Vibronic structure was found to be temperature dependent and became obscure at over 120 K. Huang–Rhys factor S and Debye temperature Θ{sub D} were estimated from the temperature dependence of the 230 nm band by curve-fitting method using Debye approximation. Origin of the vibronic photoexcitation band was suggested as F center.

  9. Tritium release from neutron irradiated beryllium pebbles

    Energy Technology Data Exchange (ETDEWEB)

    Scaffidi-Argentina, F.; Werle, H. [Forschungszentrum Karlsruhe GmbH Technik und Umwelt (Germany). Inst. fuer Neutronenphysik und Reactortechnik

    1998-01-01

    One of the most important open issues related to beryllium for fusion applications refers to the kinetics of the tritium release as a function of neutron fluence and temperature. The EXOTIC-7 as well as the `Beryllium` experiments carried out in the HFR reactor in Petten are considered as the most detailed and significant tests for investigating the beryllium response under neutron irradiation. This paper reviews the present status of beryllium post-irradiation examinations performed at the Forschungszentrum Karlsruhe with samples from the above mentioned irradiation experiments, trying to elucidate the tritium release controlling processes. In agreement with previous studies it has been found that release starts at about 500-550degC and achieves a maximum at about 700-750degC. The observed release at about 500-550degC is probably due to tritium escaping from chemical traps, while the maximum release at about 700-750degC is due to tritium escaping from physical traps. The consequences of a direct contact between beryllium and ceramics during irradiation, causing tritium implanting in a surface layer of beryllium up to a depth of about 40 mm and leading to an additional inventory which is usually several times larger than the neutron-produced one, are also presented and the effects on the tritium release are discussed. (author)

  10. Specific features of low-temperature conductivity of irradiated p-Ge

    Energy Technology Data Exchange (ETDEWEB)

    Klimkovich, B.V.; Poklonskij, N.A.; Stel' makh, V.F. (Belorusskij Gosudarstvennyj Univ., Minsk)

    1984-05-01

    It is shown that a nonconservation of the transverse in momentum component during the electron-phonon interaction the presence of dislocations leads to the tau(p) approximately psup(-7/2) momentum relaxation time dependence for the case, when the hole energy is considerably below than the thermal one, and to the tau(p) approximately p/sup -7/ dependence for the case, when the hole energy is considerably in excess of the thermal one. Results are compared with experimental data on dislocation conductivity of irradiated p-Ge.

  11. Neutron diffraction and electrical transport studies on magnetic ordering in terbium at high pressures and low temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Sarah [University of Alabama, Birmingham; Montgomery, Jeffrey M [University of Alabama, Birmingham; Tsoi, Georgiy [University of Alabama, Birmingham; Vohra, Yogesh [University of Alabama, Birmingham; Chesnut, Gary Neal [University of Alabama, Birmingham; Weir, S. T. [Lawrence Livermore National Laboratory (LLNL); Tulk, Christopher A [ORNL; Moreira Dos Santos, Antonio F [ORNL

    2013-01-01

    Neutron diffraction and electrical transport measurements have been carried out on the heavy rare-earth metal terbium at high pressures and low temperatures in order to elucidate the onset of ferromagnetic (FM) order as a function of pressure. The electrical resistance measurements show a change in slope as the temperature is lowered through the FM Curie temperature. The temperature of this FM transition decreases at a rate of-16.7 K/GPa up to a pressure of 3.6 GPa, at which point the onset of FM order is suppressed. The neutron diffraction measurements as a function of pressure at temperatures ranging from 90 to 290 K confirm that the change of slope in the resistance is associated with the FM ordering, since this occurs at pressures similar to those determined from the resistance results at these temperatures. A disappearance of FM ordering was observed as the pressure is increased above 3.6 GPa and is correlated with the phase transition from the ambient hexagonal close packed structure to an -Sm-type structure at high pressures.

  12. Neutron Spectrum Measurements from Irradiations at NCERC

    Energy Technology Data Exchange (ETDEWEB)

    Jackman, Kevin Richard [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Mosby, Michelle A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Bredeweg, Todd Allen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hutchens, Gregory Joe [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); White, Morgan Curtis [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-04-15

    Several irradiations have been conducted on assemblies (COMET/ZEUS and Flattop) at the National Criticality Experiments Research Center (NCERC) located at the Nevada National Security Site (NNSS). Configurations of the assemblies and irradiated materials changed between experiments. Different metallic foils were analyzed using the radioactivation method by gamma-ray spectrometry to understand/characterize the neutron spectra. Results of MCNP calculations are shown. It was concluded that MCNP simulated spectra agree with experimental measurements, with the caveats that some data are limited by statistics at low-energies and some activation foils have low activities.

  13. Vanadium irradiation at ATR - neutronics aspects

    Energy Technology Data Exchange (ETDEWEB)

    Gomes, I.C.; Smith, D.L. [Argonne National Laboratory, Chicago, IL (United States)

    1995-04-01

    Calculations were performed to estimate damage and transmutation rates in vanadium irradiated in the ATR (Advanced Test Reactor) located in Idaho. The main focuses of the study are to evaluate the transmutation of vanadium to chromium and to explore ways to design the irradiation experiment to avoid excessive transmutation. It was found that the A-hole of ATR produces damage rate of {approximately} 0.2%/dpa of vanadium to chromium. A thermal neutron filter can be incorporated into the design to reduce the vanadium-to-chromium transmutation rate to low levels. A filter 1-2 mm thick of gadolinium or hafnium can be used.

  14. Irradiation embrittlement investigation of the Shippingport Station neutron shield tank

    Energy Technology Data Exchange (ETDEWEB)

    Rosinski, S.T.; Shack, W.J.; Chopra, O.K.

    1989-01-01

    A joint effort between the US Nuclear Regulatory Commission and the US Department of Energy is under way to investigate the low- temperature, low-fluence rate embrittlement of reactor vessel support structures through analysis of the decommissioned Shippingport Station neutron shield tank (NST). The Shippingport NST operated at a temperature of 130/degree/F (55/degree/C) and saw a maximum fluence of approximately 6 /times/ 10/sup 17/ n/cm/sup 2/, E > 1 MeV. To characterize the embrittlement behavior of the NST material, eleven 6-inch diameter discs were removed from the irradiated inner shell of the NST along with the corresponding material from the slightly irradiated outer shell. Standard Charpy V-notch tests on the most highly irradiated NST material indicate a shift in the transition temperature (measured at 15 ft-lbs) of approximately 45/degree/F (25/degree/C) after 9.25 effective full power years of operation. This shift is not as severe as that expected based on surveillance results at the High Flux Isotope Reactor. The resultant transition temperature, however, is close to the NST service temperature. A low toughness at service temperature is also indicated. 10 refs., 8 figs., 1 tab.

  15. Design, Construction, and Modeling of a 252Cf Neutron Irradiator

    Directory of Open Access Journals (Sweden)

    Blake C. Anderson

    2016-01-01

    Full Text Available Neutron production methods are an integral part of research and analysis for an array of applications. This paper examines methods of neutron production, and the advantages of constructing a radioisotopic neutron irradiator assembly using 252Cf. Characteristic neutron behavior and cost-benefit comparative analysis between alternative modes of neutron production are also examined. The irradiator is described from initial conception to the finished design. MCNP modeling shows a total neutron flux of 3 × 105 n/(cm2·s in the irradiation chamber for a 25 μg source. Measurements of the gamma-ray and neutron dose rates near the external surface of the irradiator assembly are 120 μGy/h and 30 μSv/h, respectively, during irradiation. At completion of the project, total material, and labor costs remained below $50,000.

  16. Dosimetry in Thermal Neutron Irradiation Facility at BMRR

    OpenAIRE

    2016-01-01

    Radiation dosimetry for Neutron Capture Therapy (NCT) has been performed since 1959 at Thermal Neutron Irradiation Facility (TNIF) of the three-megawatt light-water cooled Brookhaven Medical Research Reactor (BMRR). In the early 1990s when more effective drug carriers were developed for NCT, in which the eye melanoma and brain tumors in rats were irradiated in situ, extensive clinical trials of small animals began using a focused thermal neutron beam. To improve the dosimetry at irradiation f...

  17. Positron annihilation in neutron-irradiated germanium

    Energy Technology Data Exchange (ETDEWEB)

    Bartenev, G.M.; Bardyshev, I.I.; Erchak, D.P.; Stel' makh, V.F.; Tsyganov, A.D.

    1979-04-01

    The annealing of radiation defects in a germanium single crystal irradiated with 10/sup 18/ neutrons/cm/sup 2/ was studied by positron annihilation, ESR, and resistivity measurements. It was found that positrons are trapped by radiation defects. The intensity of the narrow component of the angular correlation of the annihilation radiation yielded the concentration of defect clusters in the irradiated sample n/sub d/approx. =3 x 10/sup 14/ cm/sup -3/. Three characteristic annealing stages were identified. At 160--200 /sup 0/C, point defects were annealed within the crystal. At 200--320 /sup 0/C, there was ''loosening'' of the clusters, and the charge state of the defects changed. At 320--550 /sup 0/C, the clusters were annealed.

  18. Embrittlement of molybdenum-rhenium welds under low and high temperature neutron irradiation

    Science.gov (United States)

    Krajnikov, A. V.; Morito, F.; Danylenko, M. I.

    2014-01-01

    The effect of low- and high-temperature neutron irradiation on the tensile strength, microhardness, and fracture mode has been studied for a series of Mo-Re welds with various Re concentrations. Radiation-induced hardening and concurrent ductility reduction are the key after-effects of neutron exposure. Low-temperature irradiation usually leads to a very hard embrittlement. The hardening effect is rather limited and unstable because of the lack of ductility. Irradiated specimens fail by brittle intergranular or transgranular fracture. The damaging effect of neutrons is less pronounced after high-temperature irradiation. The hardening of the matrix is rather high, but irradiated specimens still keep residual plasticity. High-temperature irradiation intensifies homogeneous nucleation of Re-rich phases, and this effect equalises the difference in mechanical properties between the different weld zones. A characteristic ductility loss exposure temperature was found to separate the temperature fields of absolutely brittle and relatively ductile behaviour. It usually varies between 850 K and 1000 K depending on the alloy composition and irradiation conditions.

  19. Irradiation temperature dependence of production efficiency of lattice defects in some neutron-irradiated oxides

    Energy Technology Data Exchange (ETDEWEB)

    Okada, Moritami [Research Reactor Institute, Kyoto University, Kumatori-cho, Sennan-gun, Osaka 5900494 (Japan)]. E-mail: okada@rri.kyoto-u.ac.jp; Atobe, Kozo [Faculty of Science, Naruto University of Education, Naruto, Tokushima 7728502 (Japan); Nakagawa, Masuo [Faculty of Education, Kagawa University, Takamatsu, Kagawa 7608522 (Japan)

    2004-11-01

    Temperature dependence of production efficiency of irradiation-induced defects in neutron-irradiated oxides has been investigated. Some oxide single crystals, MgO, {alpha}-Al{sub 2}O{sub 3} (sapphire) and TiO{sub 2} (rutile), were irradiated at several controlled temperatures, 10, 20, 50, 100, 150 and 200 K, using the low-temperature irradiation facility of Kyoto University Reactor (KUR-LTL), and at ambient temperature ({approx}370 K) in the same facility. Irradiation temperature dependence of production efficiency of a 1 {mu}m band in TiO{sub 2} differs greatly from that of anion vacancy (F-type centers) in MgO and {alpha}-Al{sub 2}O{sub 3}. Results for MgO and {alpha}-Al{sub 2}O{sub 3} show steep negative gradients from 10 to 370 K, whereas that for TiO{sub 2} includes a valley between 40 and 60 K and a hump at about 130 K, and then disappear at about 200 K. In MgO and {alpha}-Al{sub 2}O{sub 3}, this behavior can be explained by the recombination of Frenkel pairs, which is activated at higher temperature. In TiO{sub 2}, in addition to the recombination mechanism, a covalent bonding property is thought to be exerted strong influence, and it is suggested that a disappearance of the 1 {mu}m band at above 200 K is due to the recombination process of Frenkel pairs which is caused by the irradiation-induced crystallization.

  20. Neutron diffraction study of the structure and low-temperature phase transformation in ternary NiAl+M (M = Ni, Fe, Co) alloys

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ling [ORNL; Wang, Xun-Li [ORNL; Liu, Chain T [ORNL; Fernandez-Baca, Jaime A [ORNL; Fu, Chong Long [ORNL; Richardson, James W [Argonne National Laboratory (ANL); Shi, Detang [ORNL

    2007-05-01

    Neutron diffraction was used to study the structure of ternary NiAl + M (M = Ni, Fe, Cc) alloys. The experiment confirmed the predictions by first-principle calculations on site preference by solute atoms. Moreover, a universal structural transformation was observed below 20 K in alloys where Al is partially replaced by M. The extra peaks at low-temperatures do not match those from known martensite phases, but are well indexed by a cubic structure. A possible mechanism for the low-temperature phase is discussed. (c) 2007 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  1. Neutron irradiation effects on superconducting wires and insulating materials

    Energy Technology Data Exchange (ETDEWEB)

    Nishimura, Arata [National Institute for Fusion Science, 322-6 Oroshi, Toki, Gifu 509-5292 (Japan)], E-mail: nishi-a@nifs.ac.jp; Takeuchi, Takao [National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Nishijima, Shigehiro [Graduate School of Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Nishijima, Gen; Shikama, Tatsuo [Tohoku University, 2-1-1 Katahira, Aoba, Sendai, Miyagi 980-8577 (Japan); Ochiai, Kentaro [Japan Atomic Energy Agency, 2-4 Shirakata Shirane, Tokai, Naka, Ibaraki 319-1195 (Japan); Koizumi, Norikiyo [Japan Atomic Energy Agency, 801-1 Mukoyama, Naka, Ibaraki 311-0193 (Japan)

    2009-06-15

    On the progress of the Deuterium-Deuterium (D-D) or Deuterium-Tritium (D-T) burning plasma devices, the importance of neutron irradiation on superconducting magnet materials increases and the data base is desired to design the next generation devices. To carry out the investigations on the effect of neutron irradiation, neutron irradiation fields are required together with post-irradiation test facilities. In these several years, a collaboration network of neutron irradiation effect on superconducting magnet materials has been constructed. 14 MeV neutron irradiation was carried out at Fusion Neutronics Sources (FNS) in Japan Atomic Energy Agency (JAEA) and fission neutron irradiation was performed at JRR-3 in JAEA. After the irradiation, the Nb{sub 3}Sn, NbTi and Nb{sub 3}Al samples were sent to High Field Laboratory for Superconducting Materials (HFLSM) in Tohoku University and the superconducting properties were evaluated with 28 T hybrid magnet. Also, the organic insulation materials are considered to be weaker than superconducting materials against neutron irradiation and cyanate ester resin composite was fabricated and tested at the fission reactor. One clear result on Nb{sub 3}Sn was the property change of Nb{sub 3}Sn by 14 MeV neutron irradiation over 13 T. The critical current was increased by 1.4 times around 13 T but the increment of the critical current became almost zero at higher magnetic fields and the critical magnetic field of the irradiated sample showed almost the same as non-irradiated one.

  2. Current Amplification Characteristics of BJT on Fast Neutron Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Sung Ho; Sun, Gwang Min; Baek, Hani [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    BJT (Bipolar Junction Transistor) is a three-terminal device with an important feature in that the current through two terminals can be controlled by small changes we make in the current or voltage at the third terminal. This control feature allows us to amplify small AC signals or to switch the device from an on state and off state and back. Fast neutron irradiation incurs lattice damage in bulk Si. The recombination rate of minority carriers and register are increased by the lattice damage. This study will investigate the current amplification characteristics of a pnp Si BJT through fast neutron irradiation experiments. In this paper, the current amplification characteristics of a pnp Si BJT were investigated for fast neutron irradiation. The experimental results show that base-tocollector current amplification ratio is decreased with an increase in the fast neutron irradiation. These indicate that the lattice damage caused by fast neutron irradiation increases the recombination rate of minority carriers and resistor.

  3. Characteristics of the KUR Heavy Water Neutron Irradiation Facility as a neutron irradiation field with variable energy spectra

    Science.gov (United States)

    Sakurai, Yoshinori; Kobayashi, Tooru

    2000-10-01

    The Heavy Water Neutron Irradiation Facility (HWNIF) of the Kyoto University Research Reactor (KUR) was updated in March 1996, mainly for the improvement in neutron capture therapy (NCT). A striking feature of the updated facility is that the energy spectrum of the neutron beam can be controlled from almost pure thermal to epi-thermal, within 5 min by remote control under a continuous reactor operation. This feature is advantageous not only to medical science such as NCT, but also to the other research fields such as physics, engineering, biology, etc. The performance of the updated facility as a neutron irradiation field with variable energy spectra, was characterized. Thermal neutron flux, cadmium ratio, gamma-ray dose rate, etc., at the normal irradiation position for various irradiation modes were determined, mainly on the basis of the measurement using gold activation foils and thermo-luminescent dosimeters (TLDs). The emphasis was on the performance of the new neutron energy spectrum shifter and cadmium thermal neutron filter, that control the mixing ratio of thermal and epi-thermal neutrons, through the change in the heavy water thickness of the spectrum shifter and the aperture size of the cadmium filter. The evaluation of neutron energy spectra at the normal irradiation position was also performed for three representative irradiation modes, in which the neutron intensities are largest of all the irradiation modes. In addition, the irradiation characteristics of two irradiation devices, namely the Irradiation Rail Device and the Remote Patient Carrier, which were updated concurrently with the facility update, were evaluated.

  4. Magnetic susceptibility and magnetoresistance of neutron-irradiated doped SI whiskers

    Energy Technology Data Exchange (ETDEWEB)

    Druzhinin, A.A., E-mail: druzh@polynet.lviv.ua [Lviv Polytechnic National University, S. Bandera Str., 12, Lviv 79013 (Ukraine); International Laboratory of High Magnetic Fields and Low Temperatures, Wroclaw (Poland); Ostrovskii, I.P.; Khoverko, Yu.M. [Lviv Polytechnic National University, S. Bandera Str., 12, Lviv 79013 (Ukraine); International Laboratory of High Magnetic Fields and Low Temperatures, Wroclaw (Poland); Rogacki, K. [International Laboratory of High Magnetic Fields and Low Temperatures, Wroclaw (Poland); Litovchenko, P.G.; Pavlovska, N.T. [Institute of Nuclear Researches, NAS of Ukraine, 47, Prospect Nauky, 03028 Kyiv (Ukraine); Pavlovskyy, Yu.V.; Ugrin, Yu.O. [Ivan Franko Drohobych State Pedagogical University, 24, Franko str., 82100 Drohobych (Ukraine)

    2015-11-01

    The effect of 8.6·10{sup 17} n/cm{sup 2} fast neutron irradiation on the magnetic susceptibility and magnetoresistance of Si whiskers with impurity concentration near metal–insulator transition (MIT) has been studied. Neutron irradiated specimens with boron concentration away of MIT are mainly diamagnetic with a small amount of paramagnetic centers originated from dangling bonds on the whisker surface. It has been established that at temperatures near 4.2 K, a significant contribution to the conductivity is made by light charge carriers of low concentration but with high mobility. The as grown whiskers with impurity concentration correspondent to MIT showed hysteresis loops in magnetization at temperature of liquid helium. Besides hysteresis loops in magnetoresistance was observed for whiskers under compression stress at low temperature up to 7 K. The possible reason of the effect can be magnetic interaction between impurities centers in subsurface region of the whisker with the orbital moment of dangle bounds in the whisker core–shell interstices. - Highlights: • Neutron irradiation influence on magnetic susceptibility of Si whiskers is studied. • Neutron irradiated Si whiskers with boron concentration away of MIT are diamagnetic. • Whiskers in the vicinity to MIT showed hysteresis loops in magnetoresistance. • Whiskers in the vicinity to MIT showed hysteresis loops in magnetic susceptibility.

  5. The influence of Neutron Irradiation in CR-39 polymer

    Directory of Open Access Journals (Sweden)

    Sangeeta Prasher

    2015-06-01

    Full Text Available The script allocates the influence of neutron irradiations on the structural and optical properties of CR-39. The structural properties of the polymer have been examined using the FTIR spectrum of the pristine and neutron beam irradiated polymer. The studies reveal the increase the intensity of some bands with neutron irradiation pointing the increase in the unsaturated behavior of the polymer. The optical properties analyzed using the UV-Vis spectra made it evident that CR-39 gets easily influenced at a fluence of 1016 n/cm2. The glassy characteristics of the polymer also found to diminish with increasing neutron irradiation. Significant variations in the property profile of the polymer have been observed at higher neutron fluence.

  6. Neutron Flux Characterization of Irradiation Holes for Irradiation Test at HANARO

    Directory of Open Access Journals (Sweden)

    Yang Seong Woo

    2016-01-01

    Full Text Available The High flux Advanced Neutron Application ReactOr (HANARO is a unique research reactor in the Republic of Korea, and has been used for irradiation testing since 1998. To conduct irradiation tests for nuclear materials, the irradiation holes of CT and OR5 have been used due to a high fast-neutron flux. Because the neutron flux must be accurately calculated to evaluate the neutron fluence of irradiated material, it was conducted using MCNP. The neutron flux was measured using fluence monitor wires to verify the calculated result. Some evaluations have been conducted, however, more than 20% errors have frequently occurred at the OR irradiation hole, while a good agreement between the calculated and measured data was shown at the CT irradiation hole.

  7. A study by internal friction of defects produced in iron and nickel irradiated at very low temperatures; Etude au moyen du frottement interne des defauts crees par irradiation a tres basse temperature dans le fer et le nickel

    Energy Technology Data Exchange (ETDEWEB)

    Keating-Hart, G. de [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1969-07-01

    This work represents a contribution to the study of point defects in metals. After a brief review of the theory of internal friction we will discuss some technical innovations aimed at increasing the flexibility of the apparatus at our disposal. These innovations have allowed us to extend our range of measurements down to 20 deg. K. We will then discuss our experimental results. Firstly, we describe preliminary experiments on electron irradiated iron and the evidence for a laminar structure. Secondly, we present and account of the first measurements on nickel after neutron irradiation at 27 deg. K. We will compare the results with those obtained by other methods in this laboratory. Essentially we have observed transitory peaks at low temperature due to close Frenkel pairs and we have noticed the absence of a peak which would correspond to the magnetic after effect band of stage I{sub E}. An attempt is made to explain the disappearance of the observed peaks upon the application of an internal saturating magnetic field. (author) [French] Ce memoire constitue une contribution a l'etude des defauts ponctuels dans les metaux. Apres un bref apercu theorique sur le frottement interne, nous presenterons quelques realisations techniques destinees a accroitre les possibilites des instruments qui nous ont ete confies. Ces dernieres nous ont permis d'etendre la gamme des mesures jusqu'a 20 deg. K. Nous parlerons ensuite de nos resultats experimentaux. En premier lieu, ceux obtenus au cours de premieres experiences, sur le fer irradie aux electrons mettent en evidence des structures de laminage. En second lieu, nous exposerons les premieres mesures realisees sur du nickel irradie aux neutrons; nous comparerons ces resultats avec ceux obtenus par d'autres moyens experimentaux dans le laboratoire. Nous avons observe essentiellement des pics fugitifs a basse temperature dus aux paires proches de Frenckel et nous avons constate l'absence d'un pic

  8. Recent progress in low-temperature silicon detectors

    CERN Document Server

    Abreu, M; Berglund, P; Borchi, E; Borer, K; Bruzzi, M; Buontempo, S; Casagrande, L; Chapuy, S; Cindro, V; D'Ambrosio, N; De Masi, R; Devine, S R H; Dezillie, B; Dierlamm, A; Dimcovski, Zlatomir; Eremin, V; Esposito, A; Granata, V; Grigoriev, E; Grohmann, S; Härkönen, J; Hauler, F; Heijne, Erik H M; Heising, S; Hempel, O; Herzog, R; Janos, S; Jungermann, L; Konorov, I; Li, Z; Lourenço, Carlos; Rato-Mendes, P; Menichelli, D; Mikuz, M; Niinikoski, Tapio O; Pagano, S; Palmieri, V G; Paul, S; Pirollo, S; Pretzl, Klaus; Ruggiero, G; Shea, V O; Smith, K; Solano, B P; Sonderegger, Peter; Sousa, P; Tuominen, E; Verbitskaya, E; Watts, S; Wobst, E; Zavrtanik, M; Da Vià, C; de Boer, Wim

    2003-01-01

    The CERN RD39 Collaboration studies the possibility to extend the detector lifetime in a hostile radiation environment by operating them at low temperatures. The outstanding illustration is the Lazarus effect, which showed a broad operational temperature range around 130 K for neutron irradiated silicon detectors.

  9. The intrinsic gettering in neutron irradiation Czochralski-silicon

    CERN Document Server

    Li Yang Xian; Niu Ping Juan; Liu Cai Chi; Xu Yue Sheng; Yang Deren; Que Duan Lin

    2002-01-01

    The intrinsic gettering in neutron irradiated Czochralski-silicon is studied. The result shows that a denuded zone at the surface of the neutron irradiated Czochralski-silicon wafer may be formed through one-step short-time annealing. The width of the denuded zone is dependent on the annealing temperature and the dose of neutron irradiation, while it is irrelated to the annealing time in case the denuded zone is formed. The authors conclude that the interaction between the defects induced by neutron irradiation and the oxygen in the silicon accelerates the oxygen precipitation in the bulk, and becomes the dominating factor of the quick formation of intrinsic gettering. It makes the effect of thermal history as the secondary factor

  10. Glass-like, low-energy excitations in neutron-irradiated quartz

    Energy Technology Data Exchange (ETDEWEB)

    Gardner, John William [Univ. of Illinois, Urbana-Champaign, IL (United States). Dept. of Physics

    1980-01-01

    The specific heat and thermal conductivity of neutron-irradiated crystalline quartz have been measured for temperatures ≈ 0.1 to 5 K. Four types of low-energy excitations are observed in the irradiated samples, two of which can be removed selectively by heat treatment. One set of remaining excitations gives rise to low-temperature thermal behavior characteristic of glassy (amorphous) solids. The density of these glass-like excitations can be 50% the density observed in vitreous silica, yet the sample still retains long-range atomic order. In a less-irradiated sample, glass-like excitations may be present with a density only ≈ 2.5% that observed in vitreous silica and possess a similar broad energy spectrum over 0.1 to 1 K.

  11. Results on Neutron and Gamma Irradiation of Electrolytic Tilmeters

    Energy Technology Data Exchange (ETDEWEB)

    Calderon, A.; Calvo, E.; Figueroa, C. F.; Martinez-Rivero, C.; Matorras, F.; Rodrigo, T.; Vila, I.; Virto, A. L.; Alberdi, J.; Arce, P.; Barcala, J. M.; Fernando, A.; Fuentes, J.; Josa, M. I.; Luque, J. M.; Molinero, A.; Navarrate, J.; Valdivieso, P.; Fenyvesi, A.; Molnar, J.

    2004-07-01

    We report on irradiation studies done to a sample of high precision electrolytic tiltmeters with gamma-rays, up to a maximum dose of 150 kGy, an neutrons, up to a maximum fluence 1.5x10''14 cm''2. The effect of the irradiation on their performance is discussed. (Author) 19 refs.

  12. Tensile and fracture toughness test results of neutron irradiated beryllium

    Energy Technology Data Exchange (ETDEWEB)

    Chaouadi, R.; Moons, F.; Puzzolante, J.L. [Centre d`Etude de l`Energie Nucleaire, Mol (Belgium)

    1998-01-01

    Tensile and fracture toughness test results of four Beryllium grades are reported here. The flow and fracture properties are investigated by using small size tensile and round compact tension specimens. Irradiation was performed at the BR2 material testing reactor which allows various temperature and irradiation conditions. The fast neutron fluence (>1 MeV) ranges between 0.65 and 2.45 10{sup 21} n/cm{sup 2}. In the meantime, un-irradiated specimens were aged at the irradiation temperatures to separate if any the effect of temperature from irradiation damage. Test results are analyzed and discussed, in particular in terms of the effects of material grade, test temperature, thermal ageing and neutron irradiation. (author)

  13. Neutron and gamma irradiation effects on power semiconductor switches

    Science.gov (United States)

    Schwarze, G. E.; Frasca, A. J.

    1990-01-01

    The performance characteristics of high power semiconductor switches subjected to high levels of neutron fluence and gamma dose must be known by the designer of the power conditioning, control and transmission subsystem of space nuclear power systems. Location and the allowable shielding mass budget will determine the level of radiation tolerance required by the switches to meet performance and reliability requirements. Neutron and gamma ray interactions with semiconductor materials and how these interactions affect the electrical and switching characteristics of solid state power switches is discussed. The experimental measurement system and radiation facilities are described. Experimental data showing the effects of neutron and gamma irradiation on the performance characteristics are given for power-type NPN Bipolar Junction Transistors (BJTs), and Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs). BJTs show a rapid decrease in gain, blocking voltage, and storage time for neutron irradiation, and MOSFETs show a rapid decrease in the gate threshold voltage for gamma irradiation.

  14. 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.)

  15. Neutron and gamma irradiation damage to organic materials.

    Energy Technology Data Exchange (ETDEWEB)

    White, Gregory Von, II; Bernstein, Robert

    2012-04-01

    This document discusses open literature reports which investigate the damage effects of neutron and gamma irradiation on polymers and/or epoxies - damage refers to reduced physical chemical, and electrical properties. Based on the literature, correlations are made for an SNL developed epoxy (Epon 828-1031/DDS) with an expected total fast-neutron fluence of {approx}10{sup 12} n/cm{sup 2} and a {gamma} dosage of {approx}500 Gy received over {approx}30 years at < 200 C. In short, there are no gamma and neutron irradiation concerns for Epon 828-1031/DDS. To enhance the fidelity of our hypotheses, in regards to radiation damage, we propose future work consisting of simultaneous thermal/irradiation (neutron and gamma) experiments that will help elucidate any damage concerns at these specified environmental conditions.

  16. Neutron flux assessment of a neutron irradiation facility based on inertial electrostatic confinement fusion.

    Science.gov (United States)

    Sztejnberg Gonçalves-Carralves, M L; Miller, M E

    2015-12-01

    Neutron generators based on inertial electrostatic confinement fusion were considered for the design of a neutron irradiation facility for explanted organ Boron Neutron Capture Therapy (BNCT) that could be installed in a health care center as well as in research areas. The chosen facility configuration is "irradiation chamber", a ~20×20×40 cm(3) cavity near or in the center of the facility geometry where samples to be irradiated can be placed. Neutron flux calculations were performed to study different manners for improving scattering processes and, consequently, optimize neutron flux in the irradiation position. Flux distributions were assessed through numerical simulations of several models implemented in MCNP5 particle transport code. Simulation results provided a wide spectrum of combinations of net fluxes and energy spectrum distributions. Among them one can find a group that can provide thermal neutron fluxes per unit of production rate in a range from 4.1·10(-4) cm(-2) to 1.6·10(-3) cm(-2) with epithermal-to-thermal ratios between 0.3% and 13% and fast-to-thermal ratios between 0.01% to 8%. Neutron generators could be built to provide more than 10(10) n s(-1) and, consequently, with an arrangement of several generators appropriate enough neutron fluxes could be obtained that would be useful for several BNCT-related irradiations and, eventually, for clinical practice.

  17. Microstructural investigations of materials for low temperature co-fired ceramic (LTCC) based fuel cell using small angle neutron scattering

    Science.gov (United States)

    Mohamed, A. A.; Ahmad, M. H.; Ibrahim, A.; Azman, A.; Alias, R.; Ambak, Z.; Shapee, S.; Putra, E. G.; Patriati, A.; Sharom, M. A.; Yazid, H.; Mamat, M. R.; Karim, J. A.; Idris, F. M.; Yazid, K.; Zin, M. R.

    2013-06-01

    The concept and the realization fuel cell based on LTCC technology require the investigations of fired LTCC microstructures. The majority of the works involved using small angle neutron scattering studies on the microstructural of LTCC ceramic tape and development of neutron tomography for future tool to visualize channels inside the fired tape. Most SANS characterization were carried out at Smarter SANS instrument at BATAN, Indonesia. Standard sample for resolving tens of micron of object size were measured using simple neutron tomography setup utilizing monochromatic SANS beam at Malaysian Nuclear Agency. The initial microstructural findings indicates that organic additives shape the final microstructural of LTCC after firing with the glassy material possibly fill the space left by the burned organic additives. The tomography results showed that 40 micron size object can be differentiated. The conductor deposited on LTCC is preliminary investigated which will later be used as support for catalyst.

  18. Low-temperature dynamics of magnetic colloids studied by time-resolved small-angle neutron scattering

    NARCIS (Netherlands)

    Wiedenmann, A.; Keiderling, U.; Meissner, M.; Wallacher, D.; Gähler, R.; May, R.P.; Prévost, S.; Klokkenburg, M.; Erne, B.H.; Kohlbrecher, J.

    2008-01-01

    The dynamics of ordering and relaxation processes in magnetic colloids has been studied by means of stroboscopic small angle neutron scattering techniques in an oscillating magnetic field. Surfactant stabilized ferrofluids (FFs) of Fe3O4 and Co nanoparticles have been investigated as a function of t

  19. Monte Carlo Calculations for Neutron and Gamma Radiation Fields on a Fast Neutron Irradiation Device

    Science.gov (United States)

    Vieira, A.; Ramalho, A.; Gonçalves, I. C.; Fernandes, A.; Barradas, N.; Marques, J. G.; Prata, J.; Chaussy, Ch.

    We used the Monte Carlo program MCNP to calculate the neutron and gamma fluxes on a fast neutron irradiation facility being installed on the Portuguese Research Reactor (RPI). The purpose of this facility is to provide a fast neutron beam for irradiation of electronic circuits. The gamma dose should be minimized. This is achieved by placing a lead shield preceded by a thin layer of boral. A fast neutron flux of the order of 109 n/cm2s is expected at the exit of the tube, while the gamma radiation is kept below 20 Gy/h. We will present results of the neutron and gamma doses for several locations along the tube and different thickness of the lead shield. We found that the neutron beam is very collimated at the end of the tube with a dominant component on the fast region.

  20. Lack of influence of low temperature, light and growth substances on phytochrome resynthesis in coleoptiles of irradiated oat seedlings

    Directory of Open Access Journals (Sweden)

    Jan Kopcewicz

    2014-02-01

    Full Text Available The photoconversion of phytochrome PR into the PFR form causes at the same time the destruction of the initial large fraction of phytochrome found in the coleoptiles of etiolated oat seedlings. Factors such as low temperature, light of different wavelengths or growth substances are not capable of preventing the progressive destruction and restore the synthesis of phytochrome. Thus an abnormally high level of phytochrome is found only in etiolated seedlings. Such seedlings, on the other hand, are characterized by a very high rate of elongation growth. The role of phytochrome in the control of deetiolation of seedlings is discussed.

  1. High-resolution neutron diffraction study of CuNCN: new evidence of structure anomalies at low temperature.

    Science.gov (United States)

    Jacobs, Philipp; Houben, Andreas; Tchougréeff, Andrei L; Dronskowski, Richard

    2013-12-14

    Copper carbodiimide (CuNCN) is the nitrogen-containing analogue of cupric oxide. Based on high-resolution neutron-diffraction data, CuNCN's lattice parameters are derived as a function of the temperature. In accordance with a recent synchrotron study, a clear trend in the cell parameter a is observed accompanying the changing magnetic behavior. With decreasing temperature, a slowly decreases to a minimum at ~100 K after which it rises again. The same trend-albeit more pronounced-is observed for the c lattice parameter at ~35 K. The herein presented neutron powder-diffraction data also support the conjectured sequence of transitions from the high-temperature one-dimensional resonating valence-bond (RVB) state to a transient two-dimensional RVB state and eventually, at lowest temperatures, into another two-dimensional RVB state, presumably the ground state.

  2. Irradiation facilities at the spallation neutron source SINQ

    Energy Technology Data Exchange (ETDEWEB)

    Lehmann, E.; Ledermann, J.; Aebersold, H.; Kuehne, G.; Kohlik, K. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-09-01

    Four independent experiments for sample irradiation are under construction and in preparation for operational tests at the spallation source SINQ. Three of them are located inside a thermal beam port with end positions inside or near the moderator tank. The other experiment will be established at the end position of a super mirror lined neutron guide for applications with cold neutrons. (author) 3 figs., 1 tab., 6 refs.

  3. Viability of Cladosporium herbarum spores under 157 nm laser and vacuum ultraviolet irradiation, low temperature (10 K) and vacuum

    Energy Technology Data Exchange (ETDEWEB)

    Sarantopoulou, E., E-mail: esarant@eie.gr; Stefi, A.; Kollia, Z.; Palles, D.; Cefalas, A. C. [National Hellenic Research Foundation, Theoretical and Physical Chemistry Institute, 48 Vassileos Constantinou Avenue, Athens 11635 (Greece); Petrou, P. S.; Bourkoula, A.; Koukouvinos, G.; Kakabakos, S. [N.C.S.R. “Demokritos”, Institute for Nuclear and Radiological Sciences, Energy, Technology and Safety, Patriarchou Gregoriou Str. Aghia Paraskevi, Athens 15310 (Greece); Velentzas, A. D. [University of Athens, Faculty of Biology, Department of Cell Biology and Biophysics, Athens 15784 (Greece)

    2014-09-14

    Ultraviolet photons can damage microorganisms, which rarely survive prolonged irradiation. In addition to the need for intact DNA, cell viability is directly linked to the functionality of the cell wall and membrane. In this work, Cladosporium herbarum spore monolayers exhibit high viability (7%) when exposed to 157 nm laser irradiation (412 kJm⁻²) or vacuum-ultraviolet irradiation (110–180 nm) under standard pressure and temperature in a nitrogen atmosphere. Spore viability can be determined by atomic-force microscopy, nano-indentation, mass, μ-Raman and attenuated reflectance Fourier-transform far-infrared spectroscopies and DNA electrophoresis. Vacuum ultraviolet photons cause molecular damage to the cell wall, but radiation resistance in spores arises from the activation of a photon-triggered signaling reaction, expressed via the exudation of intracellular substances, which, in combination with the low penetration depth of vacuum-ultraviolet photons, shields DNA from radiation. Resistance to phototoxicity under standard conditions was assessed, as was resistance to additional environmental stresses, including exposure in a vacuum, under different rates of change of pressure during pumping time and low (10 K) temperatures. Vacuum conditions were far more destructive to spores than vacuum-ultraviolet irradiation, and UV-B photons were two orders of magnitude more damaging than vacuum-ultraviolet photons. The viability of irradiated spores was also enhanced at 10 K. This work, in addition to contributing to the photonic control of the viability of microorganisms exposed under extreme conditions, including decontamination of biological warfare agents, outlines the basis for identifying bio-signaling in vivo using physical methodologies.

  4. Viability of Cladosporium herbarum spores under 157 nm laser and vacuum ultraviolet irradiation, low temperature (10 K) and vacuum

    Science.gov (United States)

    Sarantopoulou, E.; Stefi, A.; Kollia, Z.; Palles, D.; Petrou, P. S.; Bourkoula, A.; Koukouvinos, G.; Velentzas, A. D.; Kakabakos, S.; Cefalas, A. C.

    2014-09-01

    Ultraviolet photons can damage microorganisms, which rarely survive prolonged irradiation. In addition to the need for intact DNA, cell viability is directly linked to the functionality of the cell wall and membrane. In this work, Cladosporium herbarum spore monolayers exhibit high viability (7%) when exposed to 157 nm laser irradiation (412 kJm-2) or vacuum-ultraviolet irradiation (110-180 nm) under standard pressure and temperature in a nitrogen atmosphere. Spore viability can be determined by atomic-force microscopy, nano-indentation, mass, μ-Raman and attenuated reflectance Fourier-transform far-infrared spectroscopies and DNA electrophoresis. Vacuum ultraviolet photons cause molecular damage to the cell wall, but radiation resistance in spores arises from the activation of a photon-triggered signaling reaction, expressed via the exudation of intracellular substances, which, in combination with the low penetration depth of vacuum-ultraviolet photons, shields DNA from radiation. Resistance to phototoxicity under standard conditions was assessed, as was resistance to additional environmental stresses, including exposure in a vacuum, under different rates of change of pressure during pumping time and low (10 K) temperatures. Vacuum conditions were far more destructive to spores than vacuum-ultraviolet irradiation, and UV-B photons were two orders of magnitude more damaging than vacuum-ultraviolet photons. The viability of irradiated spores was also enhanced at 10 K. This work, in addition to contributing to the photonic control of the viability of microorganisms exposed under extreme conditions, including decontamination of biological warfare agents, outlines the basis for identifying bio-signaling in vivo using physical methodologies.

  5. Neutron irradiation of RPCs for the CMS experiment

    CERN Document Server

    Abbrescia, M; Belli, G; Bruno, G; Colaleo, A; Guida, R; Iaselli, G; Loddo, F; Maggi, M; Marangelli, B; Natali, S; Nuzzo, S; Pugliese, G; Ranieri, A; Romano, F

    2003-01-01

    All the CMS muon stations will be equipped with Resistive Plate Chambers (RPCs). They will be exposed to high neutron background environment during the LHC running. In order to verify the safe operation of these detectors, an irradiation test has been carried out with two RPCs at high neutron flux (about 10**8 n cm**-**2 s**- **1), integrating values of dose and fluence equivalent to 10 LHC- years. Before and after the irradiation, the performance of the detectors was studied with cosmic muons, showing no relevant aging effects. Moreover, no indication of damage or chemical changes were observed on the electrode surfaces.

  6. Microstructure and mechanical properties of neutron irradiated beryllium

    Energy Technology Data Exchange (ETDEWEB)

    Ishitsuka, E.; Kawamura, H. [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment; Terai, T.; Tanaka, S.

    1998-01-01

    Microstructure and mechanical properties of the neutron irradiated beryllium with total fast neutron fluences of 1.3 - 4.3 x 10{sup 21} n/cm{sup 2} (E>1 MeV) at 327 - 616degC were studied. Swelling increased by high irradiation temperature, high fluence, and by the small grain size and high impurity. Obvious decreasing of the fracture stress was observed in the bending test and in small grain specimens which had many helium bubbles on the grain boundary. Decreasing of the fracture stress for small grain specimens was presumably caused by crack propagation on the grain boundaries which weekend by helium bubbles. (author)

  7. Neutron irradiation study of silicon photomultipliers from different vendors

    Science.gov (United States)

    Kushpil, V.; Mikhaylov, V.; Kugler, A.; Kushpil, S.; Ladygin, V. P.; Reznikov, S. G.; Svoboda, O.; Tlustý, P.

    2017-02-01

    We present recent results on the investigation of the KETEK, ZECOTEK, HAMAMATSU and SENSL SiPM properties after irradiation by the 6-35 MeV neutrons. The typical neutron fluence was about 1012 n /cm2. The changing of the internal structure of the irradiated SiPMs was studied by the measuring of the C-V and C-f characteristics. We have observed the strong influence of the SiPM manufacturing technology on their radiation hardness. The application of the obtained results to the development of the readout electronics is discussed.

  8. Neutron flux optimization in irradiation channels at NUR research reactor

    Energy Technology Data Exchange (ETDEWEB)

    Meftah, B. [Division Reacteur, Centre de Recherche Nucleaire Draria (CRND), BP 43 Sebala DRARIA, Alger (Algeria)]. E-mail: b_meftah@yahoo.com; Zidi, T. [Division Reacteur, Centre de Recherche Nucleaire Draria (CRND), BP 43 Sebala DRARIA, Alger (Algeria); Bousbia-Salah, A. [Dipartimento di Ingegneria Meccanica, Nucleari e della Produzione, Facolta di Ingegneria, Universita di Pisa, Via Diotisalvi, 2 - 56126 Pisa (Italy)

    2006-09-15

    Optimization of neutron fluxes in experimental channels is of great concern in research reactor utilization. The general approach used at the NUR research reactor for neutron flux optimization in irradiation channels is presented. The approach is essentially based upon a judicious optimization of the core configuration combined with the improvement of reflector characteristics. The method allowed to increase the thermal neutron flux for radioisotope production purposes by more than 800%. Increases of up to 60% are also observed in levels of useful fluxes available for neutron diffraction experiments (small angle neutron scattering (SANS), neutron reflectometry, etc.). Such improvements in the neutronic characteristics of the NUR reactor opened new perspectives in terms of its utilization. More particularly, it is now possible to produce at industrial scales major radio-isotopes for medicine and industry and to perform, for the first time, material testing experiments. The cost of the irradiations in the optimized configuration is generally small when compared to those performed in the old configuration and an average reduction factor of about of 10 is expected in the case of production of Molybdenum-99 (isotope required for the manufacturing of Technetium-99 medical kits). In addition to these important results, safety analysis studies showed that the more symmetrical nature of the core geometry leads to a more adequately balanced reactivity control system and contributes quite efficiently to the operational safety of the NUR reactor. Results of comparisons between calculations and measurements for a series of parameters of importance in reactor operation and safety showed good agreement.

  9. Behavior under irradiation of super-mirror for neutron guides; Tenue sous irradiation de supermiroirs pour guides de neutrons

    Energy Technology Data Exchange (ETDEWEB)

    N' Guy-Marechal, K

    1997-10-15

    The aim of this work is to study the aging of NiCx/Ti super-mirror multilayers used in neutron guides under thermal neutron irradiation. These multilayers allow an increase of the apparent critical angle of total reflection by creating constructive interferences. Neutrons fluxes are thus increased in neutron guides made with a super-mirror coating. Thin films of one and ten bilayers have been deposited on a silicon and a borosilicate glass substrate. We have then studied the evolution of their optical, structural and mechanical properties after irradiation and annealing. After irradiation, a decrease in neutron reflectivity has been observed, due to the interdiffusion of both materials: this phenomenon was particularly important in the coatings deposited on a glass substrate. X-ray diffraction and X-ray absorption spectroscopy have shown that the structural evolutions of both nickel and titanium do not depend on the substrate. Nickel layers remain face-centered cubic after treatment, whereas the initially hexagonal closed-packed titanium becomes face-centered cubic with a texture in the [111] direction. This phase transformation has been attributed to the formation of a TiH compound containing as much as 50% hydrogen. Despite these structural changes, stress relaxation has occurred after irradiation in our layers. On the contrary, the mean stress that we have determined in previous samples, elaborated in another laboratory, has increased after irradiation. Comparison of both results shows that stress evolution is linked to the deposition conditions. As stress remains almost unchanged after annealing, we may conclude that only irradiation defects, and not heating, lead to stress evolution. Our samples being very similar to real neutron guides, we can extend the results we have obtained in this work to real super-mirrors. (author)

  10. Aging under irradiation of super-mirrors used in neutron guides; Tenue sous irradiation de supermiroirs pour guides de neutrons

    Energy Technology Data Exchange (ETDEWEB)

    N`Guy-Marechal, K

    1997-10-16

    The aim of this work is to study the aging of NiC{sub x}/Ti super-mirror multilayers used in neutron guides under thermal neutron irradiation. These multilayers allow an increase of the apparent critical angle of total reflection by creating constructive interferences. Neutrons fluxes are thus increased in neutron guides made with a super-mirror coating. Thin films of one and ten bilayers have been deposited on a silicon and a borosilicate glass substrate. We have then studied the evolution of their optical, structural and mechanical properties after irradiation and annealing. After irradiation, a decrease in neutron reflectivity has been observed, due to the interdiffusion of both materials: this phenomenon was particularly important in the coatings deposited on a glass substrate. X-ray diffraction and X-ray absorption spectroscopy have shown that the structural evolutions of both nickel and titanium do not depend on the substrate. Nickel layers remain face-centered cubic after treatment, whereas the initially hexagonal closed-packed titanium becomes face-centered cubic with a texture in the [111] direction. This phase transformation has been attributed to the formation of a TiH compound containing as much as 50 % hydrogen. Despite these structural changes, stress relaxation has occurred after irradiation in our layers. On the contrary, then mean stress that we have determined in previous samples, elaborated in another laboratory, has increased after irradiation. Comparison of both results shows that stress evolution is linked to the deposition conditions. As stress remains almost unchanged after annealing, we may conclude that only irradiation defects, and not heating, lead to stress evolution. Our samples being very similar to real neutron guides, we can extend the results we have obtained in this work to real super-mirrors. (author) 62 refs.

  11. Neutron diffraction and thermal studies of amorphous CS{sub 2} realised by low-temperature vapour deposition

    Energy Technology Data Exchange (ETDEWEB)

    Yamamuro, O.; Matsuo, T. [Osaka Univ., Dept. of Chemistry, Graduate School of Sciences (Japan); Onoda-Yamamuro, N. [Tokyo Denki Univ., College of Sciences and Technology (Japan); Takeda, K. [Naruto Univ., Dept. of Chemistry, Tokushima (Japan); Munemura, H.; Tanaka, S.; Misawa, M. [Niigata Univ. (Japan). Faculty of Science

    2003-08-01

    We have succeeded in preparing amorphous carbon disulphide (CS{sub 2}) by depositing its vapour on a cold substrate at 10 K. Complete formation of the amorphous state has been confirmed by neutron diffraction and differential thermal analysis (DTA). The amorphous sample crystallized at ca. 70 K, which is lower than the hypothetical glass transition temperature (92 K) estimated from the DTA data of the (CS{sub 2}){sub x}(S{sub 2}Cl{sub 2}){sub 1-x} binary mixture. CS{sub 2}, a symmetric linear tri-atomic molecule, is the simplest of the amorphized molecular substances whose structural and thermal information has been reported so far. Comparison of the static structure factors S(Q) has shown that the orientational correlation of CS{sub 2} molecules may be much stronger in the amorphous state than in the liquid state at higher temperature. (authors)

  12. Precise Magnetic Structures of Hard Ferromagnets of ND2FE14B Type as Determined at Low Temperature from Single Crystal Neutron Diffraction

    Science.gov (United States)

    Wolfers, P.; Bacmann, M.; Fruchart, D.

    2000-09-01

    The main constituent of the hard magnet materials Nd-Fe-B is the prototype of a new ferromagnet series, the Nd2Fe14B type (Space Group P42/nmm). Such compounds are characterised by high magnetocrystalline anisotropy parameters, those of rare earth origin being several times higher than the contribution of the iron subblattices. In many cases, these two contributions exhibit markedly different thermal behaviours, resulting in spin rotation phenomena or (and) lowering of the crystalline and the magnetic symmetry from the tetragonal high temperature state. Low temperature very precise studies on selected compounds of the series R2Fe14B with R = Nd, Ho, Er and Y, were undertaken by using neutron four circle diffractometry on single crystals. When temperature is lowered, the two first compounds exhibit a continuous spin reorientation within the [110] plane from the c-axis at high temperature towards an intermediate direction. The Er compound presents a first order transition around 350K where the resulting magnetisation first order rotates from the c-axis a high temperature to the a basal plane direction at low temperature. The last one compound remains c-easy axis in the whole temperature range. From our neutron diffraction experiments, lowering of the crystal symmetry to monoclinic (orthorhombic) space groups was precisely measured for the two first (third) samples. Besides marked deviations to collinearity affect the different sublattice magnetisations. Yet, these well marked phenomena have not been accounted for in the hundert experimental and theoretical analysis dedicated to the series. However, our results are in good agreement with a detailed 57Fe Mössbauer spectroscopy analysis of the Ho ternary hydrides.

  13. Annealing behaviors of vacancy in varied neutron irradiated Czochralski silicon

    Institute of Scientific and Technical Information of China (English)

    CHEN Gui-feng; LI Yang-xian; LIU Li-li; NIU Ping-juan; NIU Sheng-li; CHEN Dong-feng

    2006-01-01

    The difference of annealing behaviors of vacancy-oxygen complex (VO) in varied dose neutron irradiated Czochralski silicon: (S1 5×1017 n/cm3 and S2 1.07×1019 n/cm3) were studied. The results show that the VO is one of the main defects formed in neutron irradiated Czochralski silicon (CZ-Si). In this defect,oxygen atom shares a vacancy,it is bonded to two silicon neighbors. Annealed at 200 ℃,divacancies are trapped by interstitial oxygen(Oi) to form V2O (840 cm-1). With the decrease of the 829 cm-1 (VO) three infrared absorption bands at 825 cm-1 (V2O2),834 cm-1 (V2O3) and 840 cm-1 (V2O) will rise after annealed at temperature range of 200-500 ℃. After annealed at 450-500 ℃ the main absorption bands in S1 sample are 834 cm-1,825 cm-1 and 889 cm-1 (VO2),in S2 is 825 cm-1. Annealing of A-center in varied neutron irradiated CZ-Si is suggested to consist of two processes. The first is due to trapping of VO by Oi in low dose neutron irradiated CZ-Si (S1) and the second is due to capture the wandering vacancy by VO,etc,in high dose neutron irradiated CZ-Si (S2),the VO2 plays an important role in the annealing of A-center. With the increase of the irradiation dose,the annealing behavior of A-center is changed.

  14. Dosimetry in Thermal Neutron Irradiation Facility at BMRR

    Directory of Open Access Journals (Sweden)

    Hu J.-P.

    2016-01-01

    Full Text Available Radiation dosimetry for Neutron Capture Therapy (NCT has been performed since 1959 at Thermal Neutron Irradiation Facility (TNIF of the three-megawatt light-water cooled Brookhaven Medical Research Reactor (BMRR. In the early 1990s when more effective drug carriers were developed for NCT, in which the eye melanoma and brain tumors in rats were irradiated in situ, extensive clinical trials of small animals began using a focused thermal neutron beam. To improve the dosimetry at irradiation facility, a series of innovative designs and major modifications made to enhance the beam intensity and to ease the experimental sampling at BMRR were performed; including (1 in-core fuel addition to increase source strength and balance flux of neutrons towards two ports, (2 out of core moderator remodeling, done by replacing thicker D2O tanks at graphite-shutter interfacial areas, to expedite neutron thermalization, (3 beam shutter upgrade to reduce strayed neutrons and gamma dose, (4 beam collimator redesign to optimize the beam flux versus dose for animal treatment, (5 beam port shielding installation around the shutter opening area (lithium-6 enriched polyester-resin in boxes, attached with polyethylene plates to reduce prompt gamma and fast neutron doses, (6 sample holder repositioning to optimize angle versus distance for a single organ or whole body irradiation, and (7 holder wall buildup with neutron reflector materials to increase dose and dose rate from scattered thermal neutrons. During the facility upgrade, reactor dosimetry was conducted using thermoluminescent dosimeters TLD for gamma dose estimate, using ion chambers to confirm fast neutron and gamma dose rate, and by the activation of gold-foils with and without cadmium-covers, for fast and thermal neutron flux determination. Based on the combined effect from the size and depth of tumor cells and the location and geometry of dosimeters, the measured flux from cadmium-difference method was 4–7

  15. Dosimetry in Thermal Neutron Irradiation Facility at BMRR

    Energy Technology Data Exchange (ETDEWEB)

    Hu, J. P. [Brookhaven National Lab. (BNL), Upton, NY (United States); Holden, N. E. [Brookhaven National Lab. (BNL), Upton, NY (United States); Reciniello, R. N.

    2014-05-23

    Radiation dosimetry for Neutron Capture Therapy (NCT) has been performed since 1959 at Thermal Neutron Irradiation Facility (TNIF) of the three-megawatt light-water cooled Brookhaven Medical Research Reactor (BMRR). In the early 1990s when more effective drug carriers were developed for NCT, in which the eye melanoma and brain tumors in rats were irradiated in situ, extensive clinical trials of small animals began using a focused thermal neutron beam. To improve the dosimetry at irradiation facility, a series of innovative designs and major modifications made to enhance the beam intensity and to ease the experimental sampling at BMRR were performed; including (1) in-core fuel addition to increase source strength and balance flux of neutrons towards two ports, (2) out of core moderator remodeling, done by replacing thicker D2O tanks at graphite-shutter interfacial areas, to expedite neutron thermalization, (3) beam shutter upgrade to reduce strayed neutrons and gamma dose, (4) beam collimator redesign to optimize the beam flux versus dose for animal treatment, (5) beam port shielding installation around the shutter opening area (lithium-6 enriched polyester-resin in boxes, attached with polyethylene plates) to reduce prompt gamma and fast neutron doses, (6) sample holder repositioning to optimize angle versus distance for a single organ or whole body irradiation, and (7) holder wall buildup with neutron reflector materials to increase dose and dose rate from scattered thermal neutrons. During the facility upgrade, reactor dosimetry was conducted using thermoluminescent dosimeters TLD for gamma dose estimate, using ion chambers to confirm fast neutron and gamma dose rate, and by the activation of gold-foils with and without cadmium-covers, for fast and thermal neutron flux determination. Based on the combined effect from the size and depth of tumor cells and the location and geometry of dosimeters, the measured flux from cadmium-difference method was 4 - 7

  16. Dosimetry in Thermal Neutron Irradiation Facility at BMRR

    Science.gov (United States)

    Hu, J.-P.; Holden, N. E.; Reciniello, R. N.

    2016-02-01

    Radiation dosimetry for Neutron Capture Therapy (NCT) has been performed since 1959 at Thermal Neutron Irradiation Facility (TNIF) of the three-megawatt light-water cooled Brookhaven Medical Research Reactor (BMRR). In the early 1990s when more effective drug carriers were developed for NCT, in which the eye melanoma and brain tumors in rats were irradiated in situ, extensive clinical trials of small animals began using a focused thermal neutron beam. To improve the dosimetry at irradiation facility, a series of innovative designs and major modifications made to enhance the beam intensity and to ease the experimental sampling at BMRR were performed; including (1) in-core fuel addition to increase source strength and balance flux of neutrons towards two ports, (2) out of core moderator remodeling, done by replacing thicker D2O tanks at graphite-shutter interfacial areas, to expedite neutron thermalization, (3) beam shutter upgrade to reduce strayed neutrons and gamma dose, (4) beam collimator redesign to optimize the beam flux versus dose for animal treatment, (5) beam port shielding installation around the shutter opening area (lithium-6 enriched polyester-resin in boxes, attached with polyethylene plates) to reduce prompt gamma and fast neutron doses, (6) sample holder repositioning to optimize angle versus distance for a single organ or whole body irradiation, and (7) holder wall buildup with neutron reflector materials to increase dose and dose rate from scattered thermal neutrons. During the facility upgrade, reactor dosimetry was conducted using thermoluminescent dosimeters TLD for gamma dose estimate, using ion chambers to confirm fast neutron and gamma dose rate, and by the activation of gold-foils with and without cadmium-covers, for fast and thermal neutron flux determination. Based on the combined effect from the size and depth of tumor cells and the location and geometry of dosimeters, the measured flux from cadmium-difference method was 4-7% lower than

  17. Radiation Damages in Aluminum Alloy SAV-1 under Neutron Irradiation

    Science.gov (United States)

    Salikhbaev, Umar; Akhmedzhanov, Farkhad; Alikulov, Sherali; Baytelesov, Sapar; Boltabaev, Azizbek

    2016-05-01

    The aim of this work was to study the effect of neutron irradiation on the kinetics of radiation damages in the SAV-1 alloy, which belongs to the group of aluminum alloys of the ternary system Al-Mg-Si. For fast-neutron irradiation by different doses up to fluence 1019 cm-2 the SAV-1 samples were placed in one of the vertical channels of the research WWR type reactor (Tashkent). The temperature dependence of the electrical resistance of the alloy samples was investigated in the range 290 - 490 K by the four-compensation method with an error about 0.1%. The experimental results were shown that at all the temperatures the dependence of the SAV-1 alloy resistivity on neutron fluence was nonlinear. With increasing neutron fluence the deviation from linearity and the growth rate of resistivity with temperature becomes more appreciable. The observed dependences are explained by means of martensitic transformations and the radiation damages in the studied alloy under neutron irradiation. The mechanisms of radiation modification of the SAV-1 alloy structure are discussed.

  18. Creation of carbon onions and coils at low temperature in near-critical benzene irradiated with an ultraviolet laser

    Energy Technology Data Exchange (ETDEWEB)

    Fukuda, Takahiro [Bio-Nano Electronics Research Centre, Toyo University, 2100, Kujirai, Kawagoe, Saitama 350-8585 (Japan); Watabe, Nami [Bio-Nano Electronics Research Centre, Toyo University, 2100, Kujirai, Kawagoe, Saitama 350-8585 (Japan); Whitby, Raymond [School of Pharmacy and Biomolecular Sciences, University of Brighton, Cockroft Building, Lewes Road, Brighton BN2 4GJ (United Kingdom); Maekawa, Toru [Bio-Nano Electronics Research Centre, Toyo University, 2100, Kujirai, Kawagoe, Saitama 350-8585 (Japan)

    2007-10-17

    Gas-liquid coexistence curves terminate at their critical points, where second-order phase transitions occur. The specific heat and compressibility increase greatly as the fluid systems approach their critical points. As a result, thermal diffusion is suppressed and the perturbations of the temperature, pressure and density propagate as acoustic waves. In this paper, we irradiate near-critical benzene with a laser beam of 266 nm in wavelength, the energy flux of which is 1.3 and 3.9 mW mm{sup -2}, and show that benzene is dissociated and various carbon nano/microstructures such as carbon onions and coils are created. Carbon onions are produced in both subcritical (200 deg. C) and supercritical (290 deg. C) benzene, whereas carbon coils are produced on an alloy catalyst composed of (Fe:Cr:Ni = 74:18:8) in supercritical benzene irradiated with a laser beam of 3.9 mW mm{sup -2}. The operational temperature of the present method is much lower than that used in conventional carbon structure synthesizing methods and a large number of carbon structures, such as carbon onions and coils, are produced in supercritical benzene.

  19. Creation of carbon onions and coils at low temperature in near-critical benzene irradiated with an ultraviolet laser

    Science.gov (United States)

    Fukuda, Takahiro; Watabe, Nami; Whitby, Raymond; Maekawa, Toru

    2007-10-01

    Gas-liquid coexistence curves terminate at their critical points, where second-order phase transitions occur. The specific heat and compressibility increase greatly as the fluid systems approach their critical points. As a result, thermal diffusion is suppressed and the perturbations of the temperature, pressure and density propagate as acoustic waves. In this paper, we irradiate near-critical benzene with a laser beam of 266 nm in wavelength, the energy flux of which is 1.3 and 3.9 mW mm-2, and show that benzene is dissociated and various carbon nano/microstructures such as carbon onions and coils are created. Carbon onions are produced in both subcritical (200 °C) and supercritical (290 °C) benzene, whereas carbon coils are produced on an alloy catalyst composed of (Fe:Cr:Ni = 74:18:8) in supercritical benzene irradiated with a laser beam of 3.9 mW mm-2. The operational temperature of the present method is much lower than that used in conventional carbon structure synthesizing methods and a large number of carbon structures, such as carbon onions and coils, are produced in supercritical benzene.

  20. Swelling and tensile properties of neutron-irradiated vanadium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Loomis, B.A.; Smith, D.L.

    1990-07-01

    Vanadium-base alloys are candidates for use as structural material in magnetic fusion reactors. In comparison to other candidate structural materials (e.g., Type 316 stainless and HT-9 ferritic steels), vanadium-base alloys such as V-15Cr-5Ti and V-20Ti have intrinsically lower long-term neutron activation, neutron irradiation after-heat, biological hazard potential, and neutron-induced helium and hydrogen transmutation rates. Moreover, vanadium-base alloys can withstand a higher surface-heat, flux than steels because of their lower thermal stress factor. In addition to having these favorable neutronic and physical properties, a candidate alloy for use as structural material in a fusion reactor must have dimensional stability, i.e., swelling resistance, and resistance to embrittlement during the reactor lifetime at a level of structural strength commensurate with the reactor operating temperature and structural loads. In this paper, we present experimental results on the swelling and tensile properties of several vanadium-base alloys after irradiation at 420, 520, and 600{degree}C to neutron fluences ranging from 0.3 to 1.9 {times} 10{sup 27} neutrons/m{sup 2} (17 to 114 atom displacements per atom (dpa)).

  1. The effect of low-temperature aging on the microstructure and deformation of uranium- 6 wt% niobium: An in-situ neutron diffraction study

    Science.gov (United States)

    Brown, D. W.; Bourke, M. A. M.; Clarke, A. J.; Field, R. D.; Hackenberg, R. E.; Hults, W. L.; Thoma, D. J.

    2016-12-01

    The mechanical properties of uranium-niobium alloys evolve with aging at relatively low temperatures due to subtle microstructural changes. In-situ neutron diffraction measurements during aging of a monoclinic U-6Nb alloy at temperatures to 573 K were performed to monitor these changes. Further, in-situ neutron diffraction studies during deformation of U-6Nb in the as-quenched state and after aging for two and eight hours at 473 K were completed to assess the influence of microstructural evolution on mechanical properties. With heating, large anisotropic changes in lattice parameter were observed followed by relaxation with time at the aging temperature. The lattice parameters return to nearly their initial values with cooling. The active plastic deformation mechanisms including, in order of occurrence, shape-memory de-twinning, mechanical twinning, and slip-mediated deformation do not change with prior aging. However, the resistance to motion of the as-quenched martensitic twin boundaries increases following aging, resulting in the observed increase in initial yield strength.

  2. A Low-Temperature Crossover in Water Dynamics in an Aqueous LiCl Solution: Diffusion Probed by Neutron Spin-Echo and NMR

    Energy Technology Data Exchange (ETDEWEB)

    Mamontov, Eugene [ORNL; Faraone, Antonio [National Institute of Standards and Technology (NIST); Hagaman, Edward {Ed} W [ORNL; Han, Kee Sung [ORNL; Fratini, E [University of Florence

    2010-01-01

    Aqueous solutions of lithium chloride are an excellent model system for studying the dynamics of water molecules down to low temperatures without freezing. The apparent dynamic crossover observed in an aqueous solution of LiCl at about 220 to 225 K [Mamontov, JPCB 2009, 113, 14073] is located practically at the same temperature as the crossover found for pure water confined in small hydrophilic pores. This finding suggests a strong similarity of water behavior in these two types of systems. At the same time, studies of solutions allow more effective explorations of the long-range diffusion dynamics, because the water molecules are not confined inside an impenetrable matrix. In contrast to the earlier incoherent quasielastic neutron scattering results obtained for the scattering momentum transfers of 0.3 {angstrom}{sup -1} {le} Q {le} 0.9 {angstrom}{sup -1}, our present incoherent neutron spin-echo measurements at a lower Q of 0.1 {angstrom}{sup -1} exhibit no apparent crossover in the relaxation times down to 200 K. At the same time, our present nuclear magnetic resonance measurements of the diffusion coefficients clearly show a deviation at the lower temperatures from the non-Arrhenius law obtained at the higher temperatures. Our results are consistent with a scenario in which more than one relaxational component may exist below the temperature of the dynamic crossover in water.

  3. Density minimum of confined water at low temperatures: a combined study by small-angle scattering of X-rays and neutrons.

    Science.gov (United States)

    Erko, M; Wallacher, D; Hoell, A; Hauss, T; Zizak, I; Paris, O

    2012-03-21

    A simple explanation is given for the low-temperature density minimum of water confined within cylindrical pores of ordered nanoporous materials of different pore size. The experimental evidence is based on combined data from in-situ small-angle scattering of X-rays (SAXS) and neutrons (SANS), corroborated by additional wide-angle X-ray scattering (WAXS). The combined scattering data cannot be described by a homogeneous density distribution of water within the pores, as was originally suggested from SANS data alone. A two-step density model reveals a wall layer covering approximately two layers of water molecules with higher density than the residual core water in the central part of the pores. The temperature-induced changes of the scattering signal from both X-rays and neutrons are consistent with a minimum of the average water density. We show that the temperature at which this minimum occurs depends monotonically on the pore size. Therefore we attribute this minimum to a liquid-solid transition of water influenced by confinement. For water confined in the smallest pores of only 2 nm in diameter, the density minimum is explained in terms of a structural transition of the surface water layer closest to the hydrophilic pore walls.

  4. High sensitivity ethanol gas sensor based on Sn - doped ZnO under visible light irradiation at low temperature

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Peishuo; Pan, Guofeng; Zhang, Bingqiang; Zhen, Jiali; Sun, Yicai, E-mail: pgf@hebut.edu.cn [Institute of Microelectronic, Hebei University of Technology, Tianjin (China)

    2014-07-15

    Pure ZnO and 5at%, 7at%, 9at% Sn - doped ZnO materials are prepared by the chemical co - precipitation method. They were annealed by furnace at temperature range of 300 - 700ºC in air for 1h. The ZnO materials are characterized by X - ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that the Sn - doped ZnO materials appear rough porous structures. The maximum sensitivity can be achieved by doping the amount of 7 at%. It has much better sensing performance towards ethanol vapor under visible light irradiation. The response and recovery time are ~1s and ~5s, respectively. The mechanism for the improvement in the sensing properties can be explained with the surface adsorption theory and the photoactivation theory. (author)

  5. Microstructural defects in EUROFER 97 after different neutron irradiation conditions

    Directory of Open Access Journals (Sweden)

    Christian Dethloff

    2016-12-01

    Full Text Available Characterization of irradiation induced microstructural evolution is essential for assessing the applicability of structural steels like the Reduced Activation Ferritic/Martensitic steel EUROFER 97 in upcoming fusion reactors. In this work Transmission Electron Microscopy (TEM is used to determine the defect microstructure after different neutron irradiation conditions. In particular dislocation loops, voids and precipitates are analyzed concerning defect nature, density and size distribution after irradiation to 15 dpa at 300 °C in the mixed spectrum High Flux Reactor (HFR. New results are combined with previously obtained data from irradiation in the fast spectrum BOR-60 reactor (15 and 32 dpa, 330 °C, which allows for assessment of dose and dose rate effects on the aforementioned irradiation induced defects and microstructural characteristics.

  6. Neutron irradiation damage of nuclear graphite studied by high-resolution transmission electron microscopy and Raman spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Krishna, R. [Dalton Cumbrian Facility, Dalton Nuclear Institute, The University of Manchester, Westlakes Science & Technology Park, Moor Row, Whitehaven, Cumbria, CA24 3HA (United Kingdom); Jones, A.N., E-mail: Abbie.Jones@manchester.ac.uk [Nuclear Graphite Research Group, School of MACE, The University of Manchester, Manchester, M13 9PL (United Kingdom); McDermott, L.; Marsden, B.J. [Nuclear Graphite Research Group, School of MACE, The University of Manchester, Manchester, M13 9PL (United Kingdom)

    2015-12-15

    Nuclear graphite components are produced from polycrystalline artificial graphite manufacture from a binder and filler coke with approximately 20% porosity. During the operational lifetime, nuclear graphite moderator components are subjected to fast neutron irradiation which contributes to the change of material and physical properties such as thermal expansion co-efficient, young's modulus and dimensional change. These changes are directly driven by irradiation-induced changes to the crystal structure as reflected through the bulk microstructure. It is therefore of critical importance that these irradiation changes and there implication on component property changes are fully understood. This work examines a range of irradiated graphite samples removed from the British Experimental Pile Zero (BEPO) reactor; a low temperature, low fluence, air-cooled Materials Test Reactor which operated in the UK. Raman spectroscopy and high-resolution transmission electron microscopy (HRTEM) have been employed to characterise the effect of increased irradiation fluence on graphite microstructure and understand low temperature irradiation damage processes. HRTEM confirms the structural damage of the crystal lattice caused by irradiation attributed to a high number of defects generation with the accumulation of dislocation interactions at nano-scale range. Irradiation-induced crystal defects, lattice parameters and crystallite size compared to virgin nuclear graphite are characterised using selected area diffraction (SAD) patterns in TEM and Raman Spectroscopy. The consolidated ‘D’peak in the Raman spectra confirms the formation of in-plane point defects and reflected as disordered regions in the lattice. The reduced intensity and broadened peaks of ‘G’ and ‘D’ in the Raman and HRTEM results confirm the appearance of turbulence and disordering of the basal planes whilst maintaining their coherent layered graphite structure. - Highlights: • Irradiated graphite

  7. a Study of Stress Relaxation Rate in Un-Irradiated and Neutron-Irradiated Stainless Steel

    Science.gov (United States)

    Ghauri, I. M.; Afzal, Naveed; Zyrek, N. A.

    Stress relaxation rate in un-irradiated and neutron-irradiated 303 stainless steel was investigated at room temperature. The specimens were exposed to 100 mC, Ra-Be neutron source of continuous energy 2-12 MeV for a period ranging from 4 to 16 days. The tensile deformation of the specimens was carried out using a Universal Testing Machine at 300 K. During the deformation, straining was frequently interrupted by arresting the cross head to observe stress relaxation at fixed load. Stress relaxation rate, s, was found to be stress dependent i.e. it increased with increasing stress levels σ0 both in un-irradiated and irradiated specimens, however the rate was lower in irradiated specimens than those of un-irradiated ones. A further decrease in s was observed with increase in exposure time. The experiential decrease in the relaxation rate in irradiated specimens is ascribed to strong interaction of glide dislocations with radiation induced defects. The activation energy for the movement of dislocations was found to be higher in irradiated specimens as compared with the un-irradiated ones.

  8. Accelerated 54{degree}C irradiated test of Shippingport neutron shield tank and HFIR vessel materials

    Energy Technology Data Exchange (ETDEWEB)

    Hawthorne, J.R. [Materials Engineering Associates, Inc., Lanham, MD (United States); Rosinski, S.T. [Sandia National Labs., Albuquerque, NM (United States)

    1993-01-01

    Charpy V-notch specimens (ASTM Type A) and 5.74-mm diameter tension test specimens of the Shippingport Reactor Neutron Shield Tank (NST) (outer wall material) were irradiated together with Charpy V-notch specimens of the Oak Ridge National Laboratory (ORNI), High,, Flux Isotope Reactor (HFIR) vessel (shell material), to 5.07 {times} 10{sup 17} n/cm{sup 2}, E > 1 MeV. The irradiation was performed in the Ford Nuclear Reactor (FNR), a test reactor, at a controlled temperature of 54{degrees}C (130{degrees}F) selected to approximate the prior service temperatures of the cited reactor structures. Radiation-induced elevations in the Charpy 41-J transition temperature and the ambient temperature yield strength were small and independent of specimen test orientation (ASTM LT vs. TL). The observations are consistent with prior findings for the two materials (A 212-B plate) and other like materials irradiated at low temperature (< 200{degrees}C) to low fluence. The high radiation embrittlement sensitivity observed in HFIR vessel surveillance program tests was not found in the present accelerated irradiation test. Response to 288{degrees}C-168 h postirradiation annealing was explored for the NST material. Notch ductility recovery was found independent of specimen test orientation but dependent on the temperature within the transition region at which the specimens were tested.

  9. Accelerated 54[degree]C irradiated test of Shippingport neutron shield tank and HFIR vessel materials

    Energy Technology Data Exchange (ETDEWEB)

    Hawthorne, J.R. (Materials Engineering Associates, Inc., Lanham, MD (United States)); Rosinski, S.T. (Sandia National Labs., Albuquerque, NM (United States))

    1993-01-01

    Charpy V-notch specimens (ASTM Type A) and 5.74-mm diameter tension test specimens of the Shippingport Reactor Neutron Shield Tank (NST) (outer wall material) were irradiated together with Charpy V-notch specimens of the Oak Ridge National Laboratory (ORNI), High,, Flux Isotope Reactor (HFIR) vessel (shell material), to 5.07 [times] 10[sup 17] n/cm[sup 2], E > 1 MeV. The irradiation was performed in the Ford Nuclear Reactor (FNR), a test reactor, at a controlled temperature of 54[degrees]C (130[degrees]F) selected to approximate the prior service temperatures of the cited reactor structures. Radiation-induced elevations in the Charpy 41-J transition temperature and the ambient temperature yield strength were small and independent of specimen test orientation (ASTM LT vs. TL). The observations are consistent with prior findings for the two materials (A 212-B plate) and other like materials irradiated at low temperature (< 200[degrees]C) to low fluence. The high radiation embrittlement sensitivity observed in HFIR vessel surveillance program tests was not found in the present accelerated irradiation test. Response to 288[degrees]C-168 h postirradiation annealing was explored for the NST material. Notch ductility recovery was found independent of specimen test orientation but dependent on the temperature within the transition region at which the specimens were tested.

  10. Morphological profiles of neutron and X-irradiated small intestine

    Energy Technology Data Exchange (ETDEWEB)

    Carr, K.E.; O`Shea, O.; Hazzard, R.A.; McCullough, J.S. [Queen`s Univ., Belfast, Northern Ireland (United Kingdom); Hume, S.P.; Nelson, A.C.

    1996-03-01

    This paper describes the response of mouse small intestine, at several time points after treatment with neutron or X-irradiation, using doses expected to give similar effects in terms of crypt/microcolony survival. Using resin histology, the effects of radiation on the numbers of duodenal cell types and measurements of tissue areas were assessed. The results for individual parameters and for an estimate of overall damage are given in a data display, which summarises the morphological profile of the organ after both types of radiation. Damage and recovery were seen for many of the parameters studied but there was no standard response pattern applicable for all parameters. In particular, the response of individual crypt cell types could not be predicted from knowledge of the change in crypt numbers. With regard to the holistic response of the gut, neutron irradiation appeared to have caused more damage and produced more early effects than the X-irradiation. More specifically, neutron treatment led to more damage to the neuromuscular components of the wall, while X-irradiation produced early vascular changes. (author).

  11. High-dose neutron irradiation embrittlement of RAFM steels

    Energy Technology Data Exchange (ETDEWEB)

    Gaganidze, E. [Forschungszentrum Karlsruhe, Institut fuer Materialforschung II, P.O. Box 3640, 76021 Karlsruhe (Germany)]. E-mail: ermile.gaganidze@imf.fzk.de; Schneider, H.-C. [Forschungszentrum Karlsruhe, Institut fuer Materialforschung II, P.O. Box 3640, 76021 Karlsruhe (Germany); Dafferner, B. [Forschungszentrum Karlsruhe, Institut fuer Materialforschung II, P.O. Box 3640, 76021 Karlsruhe (Germany); Aktaa, J. [Forschungszentrum Karlsruhe, Institut fuer Materialforschung II, P.O. Box 3640, 76021 Karlsruhe (Germany)

    2006-09-01

    Neutron irradiation-induced embrittlement of the reduced-activation ferritic/martensitic (RAFM) steel EUROFER97 was studied under different heat treatment conditions. Irradiation was performed in the Petten High Flux Reactor within the HFR Phase-IIb (SPICE) irradiation project up to 16.3 dpa and at different irradiation temperatures (250-450 deg. C). Several reference RAFM steels (F82H-mod, OPTIFER-Ia, GA3X and MANET-I) were also irradiated at selected temperatures. The impact properties were investigated by instrumented Charpy-V tests with subsize specimens. Embrittlement and hardening of as-delivered EUROFER97 steel are comparable to those of reference steels. Heat treatment of EUROFER97 at a higher austenitizing temperature substantially improves the embrittlement behaviour at low irradiation temperatures. Analysis of embrittlement in terms of the parameter C = {delta}DBTT/{delta}{sigma} indicates hardening-dominated embrittlement at irradiation temperatures below 350 deg. C with 0.17 {<=} C {<=} 0.53 deg. C/MPa. Scattering of C at irradiation temperatures above 400 deg. C indicates no hardening embrittlement.

  12. High-dose neutron irradiation embrittlement of RAFM steels

    Science.gov (United States)

    Gaganidze, E.; Schneider, H.-C.; Dafferner, B.; Aktaa, J.

    2006-09-01

    Neutron irradiation-induced embrittlement of the reduced-activation ferritic/martensitic (RAFM) steel EUROFER97 was studied under different heat treatment conditions. Irradiation was performed in the Petten High Flux Reactor within the HFR Phase-IIb (SPICE) irradiation project up to 16.3 dpa and at different irradiation temperatures (250-450 °C). Several reference RAFM steels (F82H-mod, OPTIFER-Ia, GA3X and MANET-I) were also irradiated at selected temperatures. The impact properties were investigated by instrumented Charpy-V tests with subsize specimens. Embrittlement and hardening of as-delivered EUROFER97 steel are comparable to those of reference steels. Heat treatment of EUROFER97 at a higher austenitizing temperature substantially improves the embrittlement behaviour at low irradiation temperatures. Analysis of embrittlement in terms of the parameter C = ΔDBTT/Δ σ indicates hardening-dominated embrittlement at irradiation temperatures below 350 °C with 0.17 ⩽ C ⩽ 0.53 °C/MPa. Scattering of C at irradiation temperatures above 400 °C indicates no hardening embrittlement.

  13. Cation disorder in high-dose, neutron-irradiated spinel

    Energy Technology Data Exchange (ETDEWEB)

    Sickafus, K.E.; Larson, A.C.; Yu, N. [Los Alamos National Lab., CA (United States)] [and others

    1995-04-01

    The objective of this effort is to determine whether MgAl{sub 2}O{sub 4} spinel is a suitable ceramic for fusion applications. The crystal structures of MgAl{sub 2}O{sub 4} spinel single crystals irradiated to high neutron fluences [>5{times}10{sup 26} n/m{sup 2} (E{sub n}>0.1 MeV)] were examined by neutron diffraction. Crystal structure refinement of the highese dose sample indicated that the average scattering strength of the tetrahedral crystal sites decreased by {approx}20% while increasing by {approx}8% on octahedral sites.

  14. Crack-free periodic porous thin films assisted by plasma irradiation at low temperature and their enhanced gas-sensing performance.

    Science.gov (United States)

    Dai, Zhengfei; Jia, Lichao; Duan, Guotao; Li, Yue; Zhang, Hongwen; Wang, Jingjing; Hu, Jinlian; Cai, Weiping

    2013-09-27

    Homogenous thin films are preferable for high-performance gas sensors because of their remarkable reproducibility and long-term stability. In this work, a low-temperature fabrication route is presented to prepare crack-free and homogenous metal oxide periodic porous thin films by oxygen plasma irradiation instead of high temperature annealing by using a sacrificial colloidal template. Rutile SnO2 is taken as an example to demonstrate the validity of this route. The crack-free and homogenous porous thin films are successfully synthesized on the substrates in situ with electrodes. The SnO2 porous thin film obtained by plasma irradiation is rich in surface OH groups and hence superhydrophilic. It exhibits a more homogenous structure and lower resistance than porous films generated by annealing. More importantly, such thin films display higher sensitivity, a lower detection threshold (100 ppb to acetone) and better durability than those that have been directly annealed, resulting in enhanced gas-sensing performance. The presented method could be applied to synthesize other metal oxide homogenous thin films and to fabricate gas-sensing devices with high performances.

  15. Study of neutron irradiated silicon counters with a fast amplifier

    Energy Technology Data Exchange (ETDEWEB)

    Bates, S.; Munday, D.J.; Parker, M.A.; Anghinolfi, F.; Chilingarov, A.; Ciasnohova, A.; Glaser, M.; Jarron, P.; Lemeilleur, F.; Santiard, J.C.; Goessling, C.; Lisowski, B.; Pilath, S.; Rolf, A.; Bonino, R.; Clark, A.G.; Kambara, H.; Wu, X.; Fretwurst, E.; Lindstroem, G.; Schulz, T.; Moorhead, G.F.; Taylor, G.N.; Tovey, S.N.; Hawkings, R.; Weidberg, A.; Teiger, J. (Cavendish Lab., Univ. of Cambridge (United Kingdom) CERN, Geneva (Switzerland) Inst. fuer Physik, Univ. Dortmund (Germany) DPNC, Geneva Univ. (Switzerland) 1. Inst. fuer Experimentalphysik, Univ. Hamburg (Germany) School of Physics, Univ. of Melbourne, Parkville, Victoria (Australia) Dept. of Nuclear Physics, Oxford Univ. (United Kingdom) Centre d' Etudes Nucleaires de Saclay, 91 Gif-sur-Yvette (France)); RD2 Collaboration

    1993-12-15

    Silicon detectors have been irradiated with fluences of up to 2.7x10[sup 13] neutrons/cm[sup 2], and have been subsequently studied using low-noise preamplifiers with a peaking time of about 15 ns. The detector response to minimum ionizing particles was found to be close to that of non-irradiated detectors. The short integration time of the preamplifier makes the shot noise due to the detector dark current tolerable up to at least 15 [mu]A/channel. (orig.)

  16. Elastic stability of high dose neutron irradiated spinel

    Energy Technology Data Exchange (ETDEWEB)

    Li, Z.; Chan, S.K. [Argonne National Lab., Chicago, IL (United States); Garner, F.A. [Pacific Northwest Lab., Richland, WA (United States)] [and others

    1995-04-01

    The objective of this effort is to identify ceramic materials that are suitable for fusion reactor applications. Elastic constants (C{sub 11}, C{sub 12}, and C{sub 44}) of spinel (MgAl{sub 2}O{sub 4}) single crystals irradiated to very high neutron fluences have geen measured by an ultrasonic technique. Although results of a neutron diffraction study show that cation occupation sites are significantly changed in the irradiated samples, no measurable differences occurred in their elastic properties. In order to understand such behavior, the elastic properties of a variety of materials with either normal or inverse spinel structures were studied. The cation valence and cation distribution appear to have little influence on the elastic properties of spinel materials.

  17. Development of positron annihilation spectroscopy for characterizing neutron irradiated tungsten

    Energy Technology Data Exchange (ETDEWEB)

    C.N. Taylor; M. Shimada; D.W. Akers; M.W. Drigert; B.J. Merrill; Y. Hatano

    2013-05-01

    Tungsten samples (6 mm diameter, 0.2 mm thick) were irradiated to 0.025 and 0.3 dpa with neutrons in the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory. Samples were then exposed to deuterium plasma in the tritium plasma experiment (TPE) at 100, 200 and 500ºC to a total fluence of 1 x 1026 m-2. Nuclear reaction analysis (NRA) and Doppler broadening positron annihilation spectroscopy (DB-PAS) were performed at various stages to characterize damage and retention. We present the first known results of neutron damaged tungsten characterized by DB-PAS in order to study defect concentration. Two positron sources, 22Na and 68Ge, probe ~58 µm and through the entire 200 µm thick samples, respectively. DB-PAS results reveal clear differences between the various irradiated samples. These results, and the calibration of DB-PAS to NRA data are presented.

  18. In vitro antileishmanial properties of neutron-irradiated meglumine antimoniate

    Energy Technology Data Exchange (ETDEWEB)

    Borborema, Samanta Etel Treiger; Nascimento, Nanci do [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), SP (Brazil). Lab. de Biologia Molecular]. E-mail: samanta@usp.br; Osso Junior, Joao Alberto [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), SP (Brazil). Centro de Radiofarmacia]. E-mail: jaosso@ipen.br; Andrade Junior, Heitor Franco de [Instituto de Medicina Tropical de Sao Paulo (IMT-SP), SP (Brazil). Lab. de Protozoologia]. E-mail:hfandrad@usp.br

    2005-10-15

    Pentavalent antimony, as meglumine antimoniate (Glucantime) or sodium stibogluconate (Pentostam), is the main treatment for leishmaniasis, a complex of diseases caused by the protozoan Leishmania, and an endemic and neglected threat in Brazil. Despite over half a century of clinical use, their mechanism of action, toxicity and pharmacokinetic data remain unknown. The analytical methods for determination of antimony in biological systems remain complex and have low sensitivity. Radiotracer studies have a potential in pharmaceutical development. The aim of this study was to obtain a radiotracer for antimony, with suitable physical and biological properties. Meglumine antimoniate was neutron irradiated inside the IEA-R1 nuclear reactor, producing two radioisotopes {sup 122} Sb and {sup 124} Sb, with high radionuclidic purity and good specific activity. This compound showed the same antileishmanial activity as the native compound. The use of the radiotracers, easily created by neutron irradiation, could be an interesting tool to solve important questions in antimonial pharmacology. (author)

  19. Neutron - Alpha irradiation response of superheated emulsion detectors

    Science.gov (United States)

    Felizardo, M.; Morlat, T.; Girard, T. A.; Kling, A.; Fernandes, A. C.; Marques, J. G.; Carvalho, F.; Ramos, A. R.

    2017-08-01

    We report new experimental investigations of the response of single superheated emulsion detectors with small droplet (<30 μm radii) size distributions to both α- and neutron irradiations. Analysis of the results in terms of the underlying detector physics yields a toy model which reasonably reproduces the observations, and identifies the initial energy of the α in the liquid and distribution of droplet sizes as primarily responsible for the detector capacity to distinguish between nuclear recoil and α events.

  20. Neutron irradiation effects on high Nicalon silicon carbide fibers

    Energy Technology Data Exchange (ETDEWEB)

    Osborne, M.C.; Steiner, D.; Snead, L.L. [Oak Ridge National Laboratory, TN (United States)

    1996-10-01

    The effects of neutron irradiation on the mechanical properties and microstructure of SiC and SiC-based fibers is a current focal point for the development of radiation damage resistant SiC/SiC composites. This report discusses the radiation effects on the Nippon Carbon Hi-Nicalon{trademark} fiber system and also discusses an erratum on earlier results published by the authors on this material. The radiation matrix currently under study is also summarized.

  1. The proposed cold neutron irradiation facility at the Breazeale reactor

    Energy Technology Data Exchange (ETDEWEB)

    Dimeo, R. M.; Sokol, P. E.; Carpenter, J. M.

    1997-01-01

    We discuss the design considerations of a Cold Neutron Irradiation Facility (CNIF) originally to have been installed at the Penn State Breazeale Reactor (PSBR). The goal of this project was to study the effects of radiation-induced damage to cryogenic moderators and, in particular, solid methane. This work evolved through the design stage undergoing a full safety analysis and received tentative approval from the PSBR Safeguards Committee but was discontinued due to budgetary constraints. (auth)

  2. Mechanical-property changes of structural composite materials after low-temperature proton irradiation: Implications for use in SSC magnet systems

    Energy Technology Data Exchange (ETDEWEB)

    Morena, J. [Ace, Inc., Stuart, FL (US); Snead, C.L. Jr. [Brookhaven National Lab., Upton, NY (US); Czajkowski, C.; Skaritka, J. [SSC Lab., Dallas, TX (US)

    1993-07-01

    Longterm physical, mechanical, electrical, and other properties of advanced composites, plastics, and other polymer materials are greatly affected by high-energy proton, neutron, electron, and gamma radiation. The effects of high-energy particles on materials is a critical design parameter to consider when choosing polymeric structural, nonstructural, and elastomeric matrix resin systems. Polymer materials used for filled resins, laminates, seals, gaskets, coatings, insulation and other nonmetallic components must be chosen carefully, and reference data viewed with caution. Most reference data collected in the high-energy physics community to date reflects material property degradation using other than proton irradiations. In most instances, the data were collected for room-temperature irradiations, not 4.2 K or other cryogenic temperatures, and at doses less than 10{sup 8}--10{sup 9} Rad. Energetic proton (and the accompanying spallation-product particles) provide good simulation fidelity to the expected radiation fields predicted for the cold-mass regions of the SSC magnets, especially the corrector magnets. The authors present here results for some structural composite materials which were part of a larger irradiation-characterization of polymeric materials for SSC applications.

  3. Evaluation of thermal neutron irradiation field using a cyclotron-based neutron source for alpha autoradiography.

    Science.gov (United States)

    Tanaka, H; Sakurai, Y; Suzuki, M; Masunaga, S; Mitsumoto, T; Kinashi, Y; Kondo, N; Narabayashi, M; Nakagawa, Y; Watanabe, T; Fujimoto, N; Maruhashi, A; Ono, K

    2014-06-01

    It is important to measure the microdistribution of (10)B in a cell to predict the cell-killing effect of new boron compounds in the field of boron neutron capture therapy. Alpha autoradiography has generally been used to detect the microdistribution of (10)B in a cell. Although it has been performed using a reactor-based neutron source, the realization of an accelerator-based thermal neutron irradiation field is anticipated because of its easy installation at any location and stable operation. Therefore, we propose a method using a cyclotron-based epithermal neutron source in combination with a water phantom to produce a thermal neutron irradiation field for alpha autoradiography. This system can supply a uniform thermal neutron field with an intensity of 1.7×10(9) (cm(-2)s(-1)) and an area of 40mm in diameter. In this paper, we give an overview of our proposed system and describe a demonstration test using a mouse liver sample injected with 500mg/kg of boronophenyl-alanine.

  4. Commercial Applications at FRM II Based on Neutron Irradiations

    Energy Technology Data Exchange (ETDEWEB)

    Gerstenberg, H.; Draack, A.; Kastenmuller, A. [Technische Universitaet Muenchen, Munchen (Germany)

    2013-07-01

    Due to its design as a heavy water moderated reactor with a very compact core FRM II, Germany's most modern and most powerful research reactor, offers excellent conditions for basic research using beam tubes. On the other hand it is equipped with various irradiation facilities to be used mainly for industrial purposes. From the very beginning of reactor operation a dedicated department had been implemented in order to provide a neutron irradiation service to interested parties on a commercial basis. As of today the most widely used application is Si doping. The semiautomatic doping facility accepts ingots with diameters between 125 mm and 200 mm and a maximum height of 500 mm. The irradiation channel is located deep in the heavy water tank and exhibits a ratio of thermal/fast neutron flux density of > 1000. This value allows the doping of Si to a target resistivity as high as 1100 Ωcm within the tight limits regarding accuracy and homogeneity specified by the customer. Typically the throughput of Si doped in FRM II sums up to about 15 t/year. Another topic of growing importance is the use of FRM II aiming the production of radioisotopes mainly for the radiopharmaceutical industry. The maybe most challenging example is the production of Lu-177 n. c. a. based on the irradiation of Yb{sub 2}O{sub 3} to a high fluence of thermal neutrons of typically 1.5E20 cm{sup -2}. The Lu-177 activity delivered to the customer is in the range of 750 GBq. With respect to further processing it turned out to be a highly advantageous to have the laboratories of ITG, the company extracting the Lu-177 from the freshly irradiated Yb{sub 2}O{sub 3} on site FRM II. Further irradiation facilities are available at FRM II in order to allow the activation of samples for analytical purposes or to irradiate samples for geochronological investigations using the fission track technique. Finally a project on the future installation of a facility dedicated to the irradiation of U-targets for

  5. Cavity nucleation and growth during helium implantation and neutron irradiation of Fe and steel

    DEFF Research Database (Denmark)

    Eldrup, Morten Mostgaard; Singh, Bachu Narain

    In order to investigate the role of He in cavity nucleation in neutron irradiated iron and steel, pure iron and Eurofer-97 steel have been He implanted and neutron irradiated in a systematic way at different temperatures, to different He and neutron doses and with different He implantation rates...

  6. Influence of neutron irradiation on the tritium retention in beryllium

    Energy Technology Data Exchange (ETDEWEB)

    Rolli, R.; Ruebel, S.; Werle, H. [Forschungszentrum Karlsruhe, Inst. fuer Neutronenphysik und Reaktortechnik, Karlsruhe (Germany); Wu, C.H.

    1998-01-01

    Carbon-based materials and beryllium are the candidates for protective layers on the components of fusion reactors facing plasma. In contact with D-T plasma, these materials absorb tritium, and it is anticipated that tritium retention increases with the neutron damage due to neutron-induced traps. Because of the poor data base for beryllium, the work was concentrated on it. Tritium was loaded into the samples from stagnant T{sub 2}/H{sub 2} atmosphere, and afterwards, the quantity of the loaded tritium was determined by purged thermal annealing. The specification of the samples is shown. The samples were analyzed by SEM before and after irradiation. The loading and the annealing equipments are contained in two different glove boxes with N{sub 2} inert atmosphere. The methods of loading and annealing are explained. The separation of neutron-produced and loaded tritium and the determination of loaded tritium in irradiated samples are reported. Also the determination of loaded tritium in unirradiated samples is reported. It is evident that irradiated samples contained much more loaded tritium than unirradiated samples. The main results of this investigation are summarized in the table. (K.I.)

  7. Stability of the Hall sensors performance under neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Duran, I.; Hron, M.; Stockel, J. [Institute of Plasma Physics, Association EURATOM/IPP.CR, Praha (Czech Republic); Viererbl, L.; Vsolak, R.; Cerva, V. [Nuclear Research Institute plc (Czech Republic); Bolshakova, I.; Holyaka, R. [Lviv Polytechnic National Univ. (Ukraine); Vayakis, G. [ITER International Team, Naka Joint Work Site, Naka, Ibaraki (Japan)

    2004-07-01

    A principally new diagnostic method must be developed for magnetic measurements in steady state regime of operation of fusion reactor. One of the options is the use of transducers based on Hall effect. The use of Hall sensors in ITER is presently limited by their questionable radiation and thermal stability. Issues of reliable operation in ITER like radiation and thermal environment are addressed in the paper. The results of irradiation tests of candidate Hall sensors in LVR-15 and IBR-2 experimental fission reactors are presented. Stable operation (deterioration of sensitivity below one percent) of the specially prepared sensors was demonstrated during irradiation by the total fluence of 3.10{sup 16} n/cm{sup 2} in IBR-2 reactor. Increasing the total neutron fluence up to 3.10{sup 17} n/cm{sup 2} resulted in deterioration of the best sensor's output still below 10% as demonstrated during irradiation in LVR-15 fission reactor. This level of neutron is already higher than the expected ITER life time neutron fluence for a sensor location just outside the ITER vessel. (authors)

  8. Study of neutron irradiated structures of ammonothermal GaN

    Science.gov (United States)

    Gaubas, E.; Ceponis, T.; Deveikis, L.; Meskauskaite, D.; Miasojedovas, S.; Mickevicius, J.; Pavlov, J.; Pukas, K.; Vaitkus, J.; Velicka, M.; Zajac, M.; Kucharski, R.

    2017-04-01

    Study of the radiation damage in GaN-based materials becomes an important aspect for possible application of the GaN detectors in the harsh radiation environment at the Large Hadron Collider and at other particle acceleration facilities. Intentionally doped and semi-insulating bulk ammonothermal GaN materials were studied to reveal the dominant defects introduced by reactor neutron irradiations. These radiation defects have been identified by combining electron spin resonance and transmission spectroscopy techniques. Characteristics of carrier lifetime dependence on neutron irradiation fluence were examined. Variations of the response of the capacitor-type sensors with neutron irradiation fluence have been correlated with the carrier lifetime changes. The measurements of the photoconductivity and photoluminescence transients have been used to study the variation of the parameters of radiative and non-radiative recombination. The examined characteristics indicate that AT GaN as a particle sensing material is radiation hard up to high hadron fluences  ⩾1016 cm‑2.

  9. Tritium release from neutron irradiated beryllium: Kinetics, long-time annealing and effect or crack formation

    Energy Technology Data Exchange (ETDEWEB)

    Scaffidi-Argentina, F.; Werle, H. [Forschungszentrum Karlsruhe, (Germany)

    1995-09-01

    Since beryllium is considered as one of the best neutron multiplier materials in the blanket of the next generation fusion reactors, several studies have been started to evaluate its behaviour under irradiation during both operating and accidental conditions. Based on safety considerations, tritium produced in beryllium during neutron irradiation represents one important issue, therefore it is necessary to investigate tritium transport processes by using a comprehensive mathematical model and comparing its predictions with well characterized experimental tests. Because of the difficulties in extrapolating the short-time tritium release tests to a longer time scale, also long-time annealing experiments with beryllium samples from the SIBELIUS irradiation. have been carried out at the Forschungszentrum Karlsruhe. Samples were annealed up to 12 months at temperatures up to 650{degrees}C. The inventory after annealing was determined by heating the samples up to 1050{degrees}C with a He+0.1 vo1% H{sub 2} purge gas. Furthermore, in order to investigate the likely effects of cracks formation eventually causing a faster tritium release from beryllium, the behaviour of samples irradiated at low temperature (40-50{degrees}C) but up to very high fast neutron fluences (0.8-3.9{center_dot}10{sup 22} cm{sup -2}, E{sub n}{ge}1 MeV) in the BR2 reactor has been investigated. Tritium was released by heating the beryllium samples up to 1050{degrees}C and purging them with He+0.1 vo1% H{sub 2}. Tritium release from high-irradiated beryllium samples showed a much faster kinetics than from the low-irradiated ones, probably because of crack formation caused by thermal stresses in the brittle material and/or by helium bubbles migration. The obtained experimental data have been compared with predictions of the code ANFIBE with the goal to better understand the physical mechanisms governing tritium behaviour in beryllium and to assess the prediction capabilities of the code.

  10. Neutron irradiation behavior of ITER candidate beryllium grades

    Energy Technology Data Exchange (ETDEWEB)

    Kupriyanov, I.B.; Gorokhov, V.A.; Nikolaev, G.N. [A.A.Bochvar All-Russia Scientific Research Inst. of Inorganic Materials (VNIINM), Moscow (Russian Federation); Melder, R.R.; Ostrovsky, Z.E.

    1998-01-01

    Beryllium is one of the main candidate materials both for the neutron multiplier in a solid breeding blanket and for the plasma facing components. That is why its behaviour under the typical for fusion reactor loading, in particular, under the neutron irradiation is of a great importance. This paper presents mechanical properties, swelling and microstructure of six beryllium grades (DshG-200, TR-30, TshG-56, TRR, TE-30, TIP-30) fabricated by VNIINM, Russia and also one - (S-65) fabricated by Brush Wellman, USA. The average grain size of the beryllium grades varied from 8 to 25 {mu}m, beryllium oxide content was 0.8-3.2 wt. %, initial tensile strength was 250-680 MPa. All the samples were irradiated in active zone of SM-3 reactor up to the fast neutron fluence (5.5-6.2) {center_dot} 10{sup 21} cm{sup -2} (2.7-3.0 dpa, helium content up to 1150 appm), E > 0.1 MeV at two temperature ranges: T{sub 1} = 130-180degC and T{sub 2} = 650-700degC. After irradiation at 130-180degC no changes in samples dimensions were revealed. After irradiation at 650-700degC swelling of the materials was found to be in the range 0.1-2.1 %. Beryllium grades TR-30 and TRR, having the smallest grain size and highest beryllium oxide content, demonstrated minimal swelling, which was no more than 0.1 % at 650-700degC and fluence 5.5 {center_dot} 10{sup 21} cm{sup -2}. Tensile and compression test results and microstructure parameters measured before and after irradiation are also presented. (author)

  11. Neutron diffraction analysis of Cr-Ni-Mo-Ti austenitic steel after cold plastic deformation and fast neutrons irradiation

    Science.gov (United States)

    Voronin, V. I.; Valiev, E. Z.; Berger, I. F.; Goschitskii, B. N.; Proskurnina, N. V.; Sagaradze, V. V.; Kataeva, N. F.

    2015-04-01

    A quantitative assessment is presented of the dislocation density and relative fractions of edge and screw dislocations in reactor-steel samples 16Cr-15Ni-3Mo-1Ti subjected to preliminary cold deformation by rolling and subsequent fast neutron irradiation using neutron diffraction analysis. The Williamson-Hall modified method was used for calculations. It is shown that the fast neutron irradiation leads to a decrease in the density of dislocations that appeared after samples deformation. The applicability of neutron diffraction analysis to the examination of dislocation structure of deformed and irradiated materials is shown.

  12. Characterization of hybrid self-powered neutron detector under neutron irradiation

    CERN Document Server

    Nakamichi, M; Yamamura, C; Nakazawa, M; Kawamura, H

    2000-01-01

    To evaluate the irradiation behaviour of a blanket mock-up on in-pile functional test, it is necessary to measure the neutron flux change in the in-pile mock-up by a neutron detector, such as the self-powered neutron detector (SPND). With its small-sized emitter, which has high sensitivity and fast response time, SPND is an indispensable tool in order to measure the local neutron flux change. In the case of an in-pile functional test, it is necessary that response time is less than 1s and ratio of SPND output current is more than 0.3 of output current of SPND with Rh emitter. Therefore, a hybrid SPND with high sensitivity and fast response time was developed. This hybrid SPND used a hybrid emitter, i.e. Co cladded Pt-13%Rh.

  13. Small-angle neutron scattering study on irradiated kappa carrageenan

    Energy Technology Data Exchange (ETDEWEB)

    Abad, Lucille [Neutron Science Laboratory, Institute for Solid State Physics, University of Tokyo, 106-1 Shirakata, Tokai, Ibaraki 319-1106 (Japan) and Philippine Nuclear Research Institute, Commonwealth Ave., Diliman, Quezon City (Philippines) and Advanced Science Research Center, Japan Atomic Energy Research Institute, 2-4 Shirane Shirakata, Tokai, Ibaraki 319-1195 (Japan)]. E-mail: lvabad@pnri.dost.gov.ph; Okabe, Satoshi [Neutron Science Laboratory, Institute for Solid State Physics, University of Tokyo, 106-1 Shirakata, Tokai, Ibaraki 319-1106 (Japan); Koizumi, Satoshi [Advanced Science Research Center, Japan Atomic Energy Research Institute, 2-4 Shirane Shirakata, Tokai, Ibaraki 319-1195 (Japan); Shibayama, Mitsuhiro [Neutron Science Laboratory, Institute for Solid State Physics, University of Tokyo, 106-1 Shirakata, Tokai, Ibaraki 319-1106 (Japan)]. E-mail: sibayama@issp.u-tokyo.ac.jp

    2006-05-31

    The structure of gamma-ray-irradiated {kappa}-carrageenan in aqueous solutions was investigated in terms of small-angle neutron scattering. The scattered intensity, I(q), of non-irradiated {kappa}-carrageenan solutions (5 wt%) was well described with an Ornstein-Zernike (OZ)-type function with the correlation length of 85 A, indicating that the {kappa}-carrageenan solution behaves just as a polymer solution in the semi-dilute regime. By increasing the irradiation dose (100 kGy), I(q) changed to a power-law function with the scattering exponent of -1.84. Further increase in dose results in a recovery of OZ-type function. This indicates that a progressive cleavage of {kappa}-carrageenan chains takes place randomly, leading to a self-similar structure at 100 kGy. This is followed by further segmentation of {kappa}-carrageenan chains.

  14. Thermal neutron irradiation field design for boron neutron capture therapy of human explanted liver.

    Science.gov (United States)

    Bortolussi, S; Altieri, S

    2007-12-01

    The selective uptake of boron by tumors compared to that by healthy tissue makes boron neutron capture therapy (BNCT) an extremely advantageous technique for the treatment of tumors that affect a whole vital organ. An example is represented by colon adenocarcinoma metastases invading the liver, often resulting in a fatal outcome, even if surgical resection of the primary tumor is successful. BNCT can be performed by irradiating the explanted organ in a suitable neutron field. In the thermal column of the Triga Mark II reactor at Pavia University, a facility was created for this purpose and used for the irradiation of explanted human livers. The neutron field distribution inside the organ was studied both experimentally and by means of the Monte Carlo N-particle transport code (MCNP). The liver was modeled as a spherical segment in MCNP and a hepatic-equivalent solution was used as an experimental phantom. In the as-built facility, the ratio between maximum and minimum flux values inside the phantom ((phi(max)/phi(min)) was 3.8; this value can be lowered to 2.3 by rotating the liver during the irradiation. In this study, the authors proposed a new facility configuration to achieve a uniform thermal neutron flux distribution in the liver. They showed that a phi(max)/phi(min) ratio of 1.4 could be obtained without the need for organ rotation. Flux distributions and dose volume histograms were reported for different graphite configurations.

  15. Neutron irradiation damage of nuclear graphite studied by high-resolution transmission electron microscopy and Raman spectroscopy

    Science.gov (United States)

    Krishna, R.; Jones, A. N.; McDermott, L.; Marsden, B. J.

    2015-12-01

    Nuclear graphite components are produced from polycrystalline artificial graphite manufacture from a binder and filler coke with approximately 20% porosity. During the operational lifetime, nuclear graphite moderator components are subjected to fast neutron irradiation which contributes to the change of material and physical properties such as thermal expansion co-efficient, young's modulus and dimensional change. These changes are directly driven by irradiation-induced changes to the crystal structure as reflected through the bulk microstructure. It is therefore of critical importance that these irradiation changes and there implication on component property changes are fully understood. This work examines a range of irradiated graphite samples removed from the British Experimental Pile Zero (BEPO) reactor; a low temperature, low fluence, air-cooled Materials Test Reactor which operated in the UK. Raman spectroscopy and high-resolution transmission electron microscopy (HRTEM) have been employed to characterise the effect of increased irradiation fluence on graphite microstructure and understand low temperature irradiation damage processes. HRTEM confirms the structural damage of the crystal lattice caused by irradiation attributed to a high number of defects generation with the accumulation of dislocation interactions at nano-scale range. Irradiation-induced crystal defects, lattice parameters and crystallite size compared to virgin nuclear graphite are characterised using selected area diffraction (SAD) patterns in TEM and Raman Spectroscopy. The consolidated 'D'peak in the Raman spectra confirms the formation of in-plane point defects and reflected as disordered regions in the lattice. The reduced intensity and broadened peaks of 'G' and 'D' in the Raman and HRTEM results confirm the appearance of turbulence and disordering of the basal planes whilst maintaining their coherent layered graphite structure.

  16. On-line DLTS investigations of the mono- and di-vacancy in p-type silicon after low temperature electron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Zangenberg, Nikolaj E-mail: nrz@ifa.au.dk; Goubet, Jean-Jacques; Nylandsted Larsen, Arne

    2002-01-01

    Using deep level transient spectroscopy (DLTS) and Laplace-DLTS, we have investigated vacancy-related defects created in boron-doped epitaxial Si by 2 MeV electron irradiations at low temperatures ({<=}40 K). The vacancy level is found at E{sub v}+0.12 eV together with a DLTS peak at E{sub v}+0.20 eV which anneals at {approx}140 K and is tentatively identified as a vacancy in a different configuration. The emission rate of the dominant vacancy-related deep level in the temperature range from 200 to 550 K, namely the (0/+) transition of the di-vacancy (V{sub 2}), displays a very large dependence of the emission rate on the electric field strength in the depletion region of the diodes. This dependence is unexpected in terms of the classical Poole-Frenkel effect, given the neutral charge state of V{sub 2} before hole capture. The effect of high fields appears to be caused by phonon assisted tunneling. When V anneals around 200 K, a new complex assigned to a vacancy-boron pair gives rise to two charge states. Quenching experiments with reverse bias show that the complex is bistable. It anneals at 260 K.

  17. SANS response of VVER440-type weld material after neutron irradiation, post-irradiation annealing and reirradiation

    OpenAIRE

    Ulbricht, Andreas; Bergner, Frank; Boehmert, Juergen; Valo, Matti; Mathon, Marie-Helene; Heinemann, Andre

    2007-01-01

    Abstract It is well accepted that the reirradiation behaviour of reactor pressure vessel (RPV) steel after annealing can be different from the original irradiation behaviour. We present the first small-angle neutron scattering (SANS) study of neutron irradiated, annealed and reirradiated VVER440-type RPV weld material. The SANS results are analysed both in terms of the size distribution of irradiation-induced defect/solute atom clusters and in terms of the ratio of total and nuclea...

  18. Evolution of the nanostructure of VVER-1000 RPV materials under neutron irradiation and post irradiation annealing

    Science.gov (United States)

    Miller, M. K.; Chernobaeva, A. A.; Shtrombakh, Y. I.; Russell, K. F.; Nanstad, R. K.; Erak, D. Y.; Zabusov, O. O.

    2009-04-01

    A high nickel VVER-1000 (15Kh2NMFAA) base metal (1.34 wt% Ni, 0.47% Mn, 0.29% Si and 0.05% Cu), and a high nickel (12Kh2N2MAA) weld metal (1.77 wt% Ni, 0.74% Mn, 0.26% Si and 0.07% Cu) have been characterized by atom probe tomography to determine the changes in the microstructure during neutron irradiation to high fluences. The base metal was studied in the unirradiated condition and after neutron irradiation to fluences between 2.4 and 14.9 × 10 23 m -2 ( E > 0.5 MeV), and the weld metal was studied in the unirradiated condition and after neutron irradiation to fluences between 2.4 and 11.5 × 10 23 m -2 ( E > 0.5 MeV). High number densities of ˜2-nm-diameter Ni-, Si- and Mn-enriched nanoclusters were found in the neutron irradiated base and weld metals. No significant copper enrichment was associated with these nanoclusters and no copper-enriched precipitates were observed. The number densities of these nanoclusters correlate with the shifts in the ΔT 41 J ductile-to-brittle transition temperature. These nanoclusters were present after a post irradiation anneal of 2 h at 450 °C, but had dissolved into the matrix after 24 h at 450 °C. Phosphorus, nickel, silicon and to a lesser extent manganese were found to be segregated to the dislocations.

  19. Study of the behaviour under neutron irradiation of hafnium diboride; Etude du comportement sous irradiation neutronique du diborure d`hafnium

    Energy Technology Data Exchange (ETDEWEB)

    Cheminant-Coatanlem, P

    1998-12-31

    Owing to its good neutron cross section and to its high melting point, hafnium diboride is a potential candidate for a use as neutron absorbing material in control rod of pressurized water reactor of the next generation. The main causes of damage under neutron irradiation in this ceramic are due to the {sup 10}B(n,{alpha}){sup 7}Li reaction that introduces in the crystal structure new atoms and point defects. The materials under consideration are the stoichiometric HfB{sub 2} compound and the HfB{sub 2} + 10 vol. % Hf compound. They are been irradiated with neutrons at several fluences and temperatures. Electron irradiations, helium and lithium implantations have been carried out in order to simulate the creation of point defects and/or fission products. Transmission and scanning electron microscopy have been used to determine damage mechanisms in HfB{sub 2}. At a low temperature (<500 deg C), irradiation defects precipitate in dislocation loops of both nature, interstitial and vacancy. Those loops have a particular organisation in the HfB{sub 2} lattice: vacancy loops are lying in the basal plane and interstitial loops in planes perpendicular to basal planes. This induces anisotropic deformation of grains that originates internal stress development. These stresses are associated with the dislocation staking and consequently with the cavity formation at grain boundaries. At a higher temperature (>700 deg C), the same dislocation loops are observed. But, in addition, the irradiation defects diffuse to grain boundaries where helium bubbles are formed. The damage caused by this latter mechanism becomes predominant. The HfB{sub 2} + 10 vol. % Hf materials is more resistant under neutron irradiation than the HfB{sub 2} pellets that display a very damaged surface. This result is explained by the fact that, on the one band, the HfB{sub 2} + 10 vol. % Hf pellets have a higher toughness than the HfB{sub 2} pellets and, on the other hand, the HfB{sub 2} + 10 vol. % Hf

  20. Impurities effect on the swelling of neutron irradiated beryllium

    Energy Technology Data Exchange (ETDEWEB)

    Donne, M.D.; Scaffidi-Argentina, F. [Institut fuer Neutronenphysik und Reaktortechnik, Karlsruhe (Germany)

    1995-09-01

    An important factor controlling the swelling behaviour of fast neutron irradiated beryllium is the impurity content which can strongly affect both the surface tension and the creep strength of this material. Being the volume swelling of the old beryllium (early sixties) systematically higher than that of the more modem one (end of the seventies), a sensitivity analysis with the aid of the computer code ANFIBE (ANalysis of Fusion Irradiated BEryllium) to investigate the effect of these material properties on the swelling behaviour of neutron irradiated beryllium has been performed. Two sets of experimental data have been selected: the first one named Western refers to quite recently produced Western beryllium, whilst the second one, named Russian refers to relatively old (early sixties) Russian beryllium containing a higher impurity rate than the Western one. The results obtained with the ANFIBE Code were assessed by comparison with experimental data and the used material properties were compared with the data available in the literature. Good agreement between calculated and measured values has been found.

  1. Spectroscopic study of fast-neutron-irradiated chromatin

    Energy Technology Data Exchange (ETDEWEB)

    Radu, L. [V. Babes National Inst., Dept. of Molecular Genetics, Bucharest (Romania)]. E-mail: serbanradu@pcnet.ro; Gazdaru, D. [Bucharest Univ., Dept. of Biophysics, Physics Faculty, Bucharest (Romania); Constantinescu, B. [H. Hulubei National Inst., Dept. of Cyclotron, Bucharest (Romania)

    2004-02-01

    The effects produced by fast neutrons (0-100 Gy) on chromatin structure were analyzed by (i) [{sup 1}H]-NMR spectroscopy, (ii) time resolved spectroscopy, and (iii) fluorescence resonance energy transfer (FRET). Two types of chromatin were tested: (i) a chromatin from a normal tissue (liver of Wistar rats) and (ii) a chromatin from a tumoral tissue (Guerin limphotrope epithelioma, a rat solid tumor). The fast-neutron action on chromatin determines greater values of the [{sup 1}H]-NMR transverse relaxation time, indicating a more injured structure. Time-resolved fluorescence measurements show that the relative contribution of the excited state lifetime of bound ethidium bromide to chromatin DNA diminishes with increasing irradiation doses. This reflects the damage that occurs in DNA structure: production of single- and double-strand breaks due to sugar and base modifications. By the FRET method, the distance between dansyl chloride and acridine orange coupled at chromatin was determined. This distance increases upon fast-neutron action. The radiosensitivity of the tumor tissue chromatin seems higher than that of the normal tissue chromatin, probably because of its higher (loose) euchromatin/(compact) heterochromatin ratio. As the values of the physical parameters analyzed are specific for a determined dose, the establishment of these parameters may constitute a criterion for the microdosimetry of chromatin radiolesions produced by fast neutrons. (author)

  2. The medical-irradiation characteristics for neutron capture therapy at the Heavy Water Neutron Irradiation Facility of Kyoto University Research Reactor.

    Science.gov (United States)

    Sakurai, Yoshinori; Kobayashi, Tooru

    2002-10-01

    At the Heavy Water Neutron Irradiation Facility of the Kyoto University Research Reactor, the mix irradiation of thermal and epi-thermal neutrons, and the solo irradiation of epi-thermal neutrons are available additionally to the thermal neutron irradiation, and then the neutron capture therapy (NCT) at this facility became more flexible, after the update in 1996. The estimation of the depth dose distributions in NCT clinical irradiation, were performed for the standard irradiation modes of thermal, mixed and epi-thermal neutrons, from the both sides of experiment and calculation. On the assumption that the 10B concentration in tumor part was 40 ppm and the ratio of tumor to normal tissue was 3.5, the advantage depth were estimated to 5.4, 6.0, and 8.0, for the respective standard irradiation modes. It was confirmed that the various irradiation conditions can be selected according to the target-volume conditions, such as size, depth, etc. Besides, in the viewpoint of the radiation shielding for patient, it was confirmed that the whole-body exposure is effectively reduced by the new clinical collimators, compared with the old one.

  3. Crystallographic changes in lead zirconate titanate due to neutron irradiation

    Directory of Open Access Journals (Sweden)

    Alexandra Henriques

    2014-11-01

    Full Text Available Piezoelectric and ferroelectric materials are useful as the active element in non-destructive monitoring devices for high-radiation areas. Here, crystallographic structural refinement (i.e., the Rietveld method is used to quantify the type and extent of structural changes in PbZr0.5Ti0.5O3 after exposure to a 1 MeV equivalent neutron fluence of 1.7 × 1015 neutrons/cm2. The results show a measurable decrease in the occupancy of Pb and O due to irradiation, with O vacancies in the tetragonal phase being created preferentially on one of the two O sites. The results demonstrate a method by which the effects of radiation on crystallographic structure may be investigated.

  4. Status of Neutron Irradiation of Non-Nuclear Materials at HANARO

    Energy Technology Data Exchange (ETDEWEB)

    Choo, Kee-Nam; Cho, Man-Soon; Shin, Yoon-Taek; Park, Seng-Jae; Kang, Young Hwan; Jun, Byung-Hyuk; Kim, Chan-Joong; Park, Sang-Jun [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-10-15

    The irradiation facilities have been mostly utilized for the KAERI nuclear research projects relevant to a commercial nuclear power reactor such as the ageing management and safety evaluation of the components. Based on the accumulated experience, HANARO has recently supported national R and D projects relevant to new nuclear systems including the System-integrated Modular Advanced Reactor (SMART), research reactors, and future nuclear systems. As neutron irradiation affects the structure of a material, radiation induced modification of materials has become a perspective method for the purposeful changes in material properties. Some irradiation tests of electro-magnetic materials were also performed at HANARO for scientific research of universities and the demand for neutron irradiation of the materials is increasing rapidly. Another research reactor that will specialize in radio-isotope and neutron transmutation doping (NTD) Si production and the demonstration of reactor design is under construction in Korea. Therefore, HANARO will specialize more on irradiation research. Based on its accumulated irradiation experience, HANARO has recently started new support of R and D relevant to the irradiation of electro-magnetic materials. In this paper, the status of utilization of the HANARO irradiation facilities for non-nuclear materials and the possibility of researches on new electro-magnetic materials using neutron irradiation are surveyed to encourage the utilization of HANARO. HANARO irradiation facilities have been actively utilized for various material irradiation tests requested by users. Although most irradiation tests have been related to national R and D relevant to nuclear power, demand for neutron irradiation of electro-magnetic materials is rapidly increasing at HANARO. Another research reactor, the KIJANG research reactor (KJRR), is under construction in Korea. New irradiation facilities including Neutron Transmutation Doping (NTD) facilities for power

  5. Distortion of neutron field during mice irradiation at Kinki University Reactor UTR-KINKI

    Energy Technology Data Exchange (ETDEWEB)

    Endo, Satoru [Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553 (Japan)], E-mail: endos@hiroshima-u.ac.jp; Tanaka, Kenichi [Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553 (Japan); Fujikawa, Kazuo; Horiguchi, Tetsuo; Itoh, Tetsuo [Atomic Energy Research Institute, Kinki University, 3-4-1 Kowakae, Higashi-Osaka 577-8502 (Japan); Bengua, Gerard [Research Reactor Institute, Kyoto University, Kumatori-cho, Sennan-gun, Osaka 590-0494 (Japan); Nomura, Taisei [Graduate Schools of Medicine and Engineering, Osaka University, B4 2-2 Yamadaoka, Suita, Osaka 565-0871 (Japan); Hoshi, Masaharu [Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553 (Japan)

    2007-09-15

    A dosimetry study of mice irradiation at the Kinki University nuclear reactor (UTR-KINKI) has been carried out. Neutron and gamma-ray doses at the irradiation port in the presence of 0, 1, 2, 4 and 6 mice were measured using the paired chamber method. The results show that neutron dose is reduced with increasing numbers of mice. In the six-mice irradiation condition, neutron dose is about 15% smaller compared to a case where no mice were placed in the irradiation port. To investigate the distortion of the neutron spectrum during mice irradiation at UTR-KINKI, a Monte Carlo calculation using the MCNP4C code has been carried out. The measured variation in dose with respect to the total mouse mass was closely reproduced by the calculation results for neutron and gamma-ray dose. Distortion of the neutron spectrum was observed to occur between 1 keV and 1 MeV.

  6. Magnetic structure at low temperatures in FeGe2

    Science.gov (United States)

    Babu, P. D.; Mishra, P. K.; Dube, V.; Mishra, R.; Sastry, P. U.; Ravikumar, G.

    2014-04-01

    Magnetic phase of FeGe2 intermetallic is studied using low-temperature neutron diffraction and DC magnetization. Zero-magnetic-field neutron scattering data shows the presence of an antiferromagnetic phase in the low temperature range. We find the evidence of the presence of a ferromagnetic order overriding on the predominantly antiferromagnetic phase at low temperatures.

  7. Microstructure and dimensional changes of neutron-irradiated zirconium alloys

    Science.gov (United States)

    Pedraza, A. J.; Fainstein-Pedraza, D.

    1982-08-01

    Experimental observations concerning the neutron-irradiation-induced defect structure in zirconium-based alloys are analyzed within the framework of an irradiation growth theory developed in the past years. The competition of those defects and the microstructure present in the material prior to irradiation as point defect sinks is studied as a function of irradiation temperature and dose. Owing to the different growth behavior of recrystallized and of cold-worked specimens at reactor temperatures, the cellular microstructure of the latter is considered in detail. In view of the highly anisotropic dislocation system in these materials, cell boundaries are reasoned to form with essentially edge components in the walls parallel to the c-axis, while the boundary segments normal to that axis should be of screw type. Since the latter would induce no dimensional change if the cell boundary absorbs defects by dislocation climb, it is argued — on the basis of growth data — that it must behave as a point defect sink/source of a different nature than that of free dislocations. The possibility of dislocation segments with a ( c + a)-type Burgers vector in the cell boundary or rapid point defect diffusion along it are also discussed. The existing growth model is then enlarged in order to account quantitatively for the dimensional changes of cold-worked materials, and its results are compared with available experimental data.

  8. Boron neutron capture irradiation: setting up a clinical programme in Nice; Irradiation par capture de neutrons: mise en place d`un programme clinique a Nice

    Energy Technology Data Exchange (ETDEWEB)

    Pignol, J.P.; Chauvel, P.; Courdi, A.; Iborra-Brassart, N.; Frenay, M.; Herault, J.; Bensadoun, R.J.; Milano, G.; Demard, F. [Centre de Lutte Contre le Cancer Antoine Lacassagne, 06 - Nice (France); Paquis, P.; Lonjon, M.; Lebrun-Frenay, C.; Grellier, P.; Chatel, M. [Hopital Pasteur, 06 - Nice (France); Nepveu, F.; Patau, J.P. [Toulouse-3 Univ., 31 (France); Breteau, N. [Hopital de la Source, 45 - Orleans (France)

    1996-12-31

    Neutron capture irradiation aims to selectively destroy tumor tumor cell using {sup 10}B(n,{alpha}){sup 7}Li nuclear reactions produced within themselves. Following the capture reaction, an {alpha} particle and a, {sup 7}Li ion are emitted. Carrying an energy of 2.79 MeV, they destroy all molecular structures along their path close to 10 {mu}m. These captures, used exclusively with a `slow` neutron irradiation, provide a neutron capture therapy (BNCT). If they are used in addition to a fast neutron beam irradiation, they provide a neutron capture potentiation (NCP). The Centre Antoine-Lacassagne in Nice is actively involved in the European Demonstration project for BNCT of grade IV glioblastomas (GBM) after surgical excision and BSH administration. Taking into account the preliminary results obtained in Japan, work on an `epithermal` neutron target compatible with various cyclotron beams is in progress to facilitate further developments of this technique. For NCP, thermalized neutron yield has been measured in phantoms irradiated in the fast neutron beam of the biomedical cyclotron in Nice. A thermal peak appears after 5 cm depth in the tissues, delayed after the fast neutron peak at 1.8 cm depth. Thus, a physical overdosage of 10 % may be obtained if 100 ppm of {sup 10}B are assumed in the tissues. Our results using CAL 58 GBM cell line demonstrate a dose modification factor (DMF) of 1.19 when 100 ppm of boric acid are added to the growth medium. Thus for the particles, issued from neutron capture, a biological efficiency at least twice that of fast neutrons can be derived. These results, compared with historical data on fast neutron irradiation of glioblastoma, suggest that a therapeutic window may be obtained for GBM. (author). 26 refs.

  9. The effect of neutron irradiation on silicon carbide fibers

    Energy Technology Data Exchange (ETDEWEB)

    Newsome, G.A. [Lockheed Martin Corp., Schenectady, NY (United States)

    1997-01-01

    Nine types of SiC fiber have been exposed to neutron radiation in the Advanced Test Reactor at 250 C for various lengths of time ranging from 83 to 128 days. The effects of these exposures have been initially determined using scanning electron microscopy. The fibers tested were Nicalon{trademark} CG, Tyranno, Hi-Nicalon{trademark}, Dow Corning SiC, Carborundum SiC, Textron SCS-6, polymethysilane (PMS) derived SiC from the University of Michigan, and two types of MER SiC fiber. This covers a range of fibers from widely used commercial fibers to developmental fibers. Consistent with previous radiation experiments, Nicalon fiber was severely degraded by the neutron irradiation. Similarly, Tyranno suffered severe degradation. The more advanced fibers which approach the composition and properties of SiC performed well under irradiation. Of these, the Carborundum SiC fiber appeared to perform the best. The Hi-Nicalon and Dow Corning Fibers exhibited good general stability, but also appear to have some surface roughening. The MER fibers and the Textron SCS-6 fibers both had carbon cores which adversely influenced the overall stability of the fibers.

  10. In vitro neutron irradiation of glioma and endothelial cultured cells

    Energy Technology Data Exchange (ETDEWEB)

    Menichetti, L. [Department of PET and Radiopharmaceutical Chemistry, C.N.R. Institute of Clinical Physiology, Pisa (Italy)], E-mail: luca.menichetti@ifc.cnr.it; Gaetano, L. [University Scuola Superiore Sant' Anna, Pisa (Italy); Zampolli, A.; Del Turco, S. [Department of PET and Radiopharmaceutical Chemistry, C.N.R. Institute of Clinical Physiology, Pisa (Italy); Ferrari, C. [University of Pavia, Department of Surgery, Laboratory of experimental Surgery, Pavia (Italy); Bortolussi, S.; Stella, S.; Altieri, S. [University of Pavia, Department of Nuclear Physics, Pavia (Italy); National Institute for Nuclear Physics (INFN), Section of Pavia (Italy); Salvadori, P.A. [Department of PET and Radiopharmaceutical Chemistry, C.N.R. Institute of Clinical Physiology, Pisa (Italy); Cionini, L. [Unit of Radiotherapy, AOUP-University Hospital, Pisa (Italy)

    2009-07-15

    To fully develop its potential boron neutron capture therapy (BNCT) requires the combination of a suitable thermal/epithermal neutron flux together with a selective intake of {sup 10}B-boron nuclei in the target tissue. The latter condition is the most critical to be realized as none of the boron carriers used for experimental or clinical purposes proved at the moment an optimal selectivity for cancer cells compared to normal cells. In addition to complex physical factors, the assessment of the intracellular concentration of boron represent a crucial parameter to predict the dose delivered to the cancer cells during the treatment. Nowadays the dosimetry calculation and then the prediction of the treatment effectiveness are made using Monte Carlo simulations, but some of the model assumption are still uncertain: the radiobiological dose efficacy and the probability of tumour cell survival are crucial parameters that needs a more reliable experimental approach. The aim of this work was to evaluate the differential ability of two cell lines to selectively concentrate the boron-10 administered as di-hydroxyboryl-phenylalanine (BPA)-fructose adduct, and the effect of the differential boron intake on the damage produced by the irradiation with thermal neutrons; the two cell lines were selected to be representative one of normal tissues involved in the active/passive transport of boron carriers, and one of the tumour. Recent in vitro studies demonstrated how BPA is taken by proliferating cells, however the mechanism of BPA uptake and the parameters driving the kinetics of influx and the elimination of BPA are still not clarified. In these preliminary studies we analysed the survival of F98 and human umbilical vein endothelial cells (HUVEC) cells line after irradiation, using different thermal fluencies at the same level of density population and boron concentration in the growing medium prior the irradiation. This is first study performed on endothelium model obtained by

  11. Neutron irradiation effects on AlGaN/GaN high electron mobility transistors

    Institute of Scientific and Technical Information of China (English)

    Lü Ling; Zhang Jin-Cheng; Xue Jun-Shuai; Ma Xiao-Hua; Zhang Wei; Bi Zhi-Wei; Zhang Yue; Hao Yue

    2012-01-01

    AlGaN/GaN high electron mobility transistors (HEMTs) were exposed to 1 MeV neutron irradiation at a neutron fluence of 1 × 1015 cm-2.The dc characteristics of the devices,such as the drain saturation current and the maximum transconductance,decreased after neutron irradiation. The gate leakage currents increased obviously after neutron irradiation.However,the rf characteristics,such as the cut-off frequency and the maximum frequency,were hardly affected by neutron irradiation.The AlGaN/GaN heterojunctions have been employed for the better understanding of the degradation mechanism.It is shown in the Hall measurements and capacitance-voltage tests that the mobility and concentration of two-dimensional electron gas (2DEG) decreased after neutron irradiation.There was no evidence of the full-width at half-maximum of X-ray diffraction (XRD) rocking curve changing after irradiation,so the dislocation was not influenced by neutron irradiation.It is concluded that the point defects induced in AlGaN and GaN by neutron irradiation are the dominant mechanisms responsible for performance degradations of AlGaN/GaN HEMT devices.

  12. Characterization of defect accumulation in neutron-irradiated Mo by positron annihilation spectroscopy

    DEFF Research Database (Denmark)

    Eldrup, Morten Mostgaard; Li, Meimei; Snead, L.L.

    2008-01-01

    Positron annihilation lifetime spectroscopy measurements were performed on neutron-irradiated low carbon arc cast Mo. Irradiation took place in the high flux isotope reactor, Oak Ridge National Laboratory, at a temperature of 80 +/- 10 degrees C. Neutron fluences ranged from 2 x 10(21) to 8 x 10...

  13. Optical absorption and luminescence in neutron-irradiated, silica-based fibers

    Energy Technology Data Exchange (ETDEWEB)

    Cooke, D.W.; Farnum, E.H.; Clinard, F.W. [Los Alamos National Lab., CA (United States)] [and others

    1995-04-01

    The objectives of this work are to assess the effects of thermal annealing and photobleaching on the optical absorption of neutron-irradiated, silica fibers of the type proposed for use in ITER diagnostics, and to measure x-ray induced luminescence of unirradiated (virgin) and neutron-irradiated fibers.

  14. Characterization of the fast neutron irradiation facility of the Portuguese Research Reactor after core conversion.

    Science.gov (United States)

    Marques, J G; Sousa, M; Santos, J P; Fernandes, A C

    2011-08-01

    The fast neutron irradiation facility of the Portuguese Research Reactor was characterized after the reduction in uranium enrichment and rearrangement of the core configuration. In this work we report on the determination of the hardness parameter and the 1MeV equivalent neutron flux along the facility, in the new irradiation conditions, following ASTM E722 standard.

  15. Fission neutron irradiation of copper containing implanted and transmutation produced helium

    DEFF Research Database (Denmark)

    Singh, B.N.; Horsewell, A.; Eldrup, Morten Mostgaard

    1992-01-01

    . The distributions of helium prior to fission neutron irradiation were determined by a combination of transmission electron microscopy (TEM) and positron annihilation techniques (PAT). These specimens, together with pure copper, were then irradiated with fission neutrons in a single capsule in fast flux test...

  16. Lithium target for accelerator based BNCT neutron source: Influence by the proton irradiation on lithium

    Science.gov (United States)

    Fujii, R.; Imahori, Y.; Nakakmura, M.; Takada, M.; Kamada, S.; Hamano, T.; Hoshi, M.; Sato, H.; Itami, J.; Abe, Y.; Fuse, M.

    2012-12-01

    The neutron source for Boron Neutron Capture Therapy (BNCT) is in the transition stage from nuclear reactor to accelerator based neutron source. Generation of low energy neutron can be achieved by 7Li (p, n) 7Be reaction using accelerator based neutron source. Development of small-scale and safe neutron source is within reach. The melting point of lithium that is used for the target is low, and durability is questioned for an extended use at a high current proton beam. In order to test its durability, we have irradiated lithium with proton beam at the same level as the actual current density, and found no deterioration after 3 hours of continuous irradiation. As a result, it is suggested that lithium target can withstand proton irradiation at high current, confirming suitability as accelerator based neutron source for BNCT.

  17. Study on changes of sperm count and testis tissue in black mouse after neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Chun, Ki Jung; Seo, Won Sook [KAERI, Daejeon (Korea, Republic of); Son, Hwa Young [Chungnam National Univ., Daejeon (Korea, Republic of)

    2006-03-15

    For the purpose of the biological effect in black mouse by neutron irradiation, mice were irradiated with 16 or 32 Gy neutron (flux: 1.036739E+09) by lying flat pose at BNCT facility on HANARO Reactors. And 90 days later of irradiation, physical changes of testis and testis tissue were examined. There were no weight changes but a little bit volume changes and sperm counts in the tests. Atrophy of seminiferous tubules irradiated with 32 Gy neutron is increased in number and severity and those in stage VI showed depletion of spermatogonia and pachytene spermatocytes compared to the non-irradiated control group. Testis damage of black mouse was not recovered after long time by 32 Gy neutron irradiation.

  18. Post-irradiation experiments on physical thermal and microstructural properties of neutron-irradiated ceramics. 2

    Energy Technology Data Exchange (ETDEWEB)

    Yano, Toyohiko [Tokyo Inst. of Tech. (Japan). Research Lab. for Nuclear Reactors

    1999-03-01

    Succeeding to the report on the post-irradiation experiments conducted in the previous year, this is a summary report on the post-irradiation experiments of physical, thermal and microstructural properties of neutron-irradiated various ceramics, which are expected to be applied to the in-core materials of an Advanced Fast Breeder Reactor in near future. Four candidate ceramics, Al{sub 2}O{sub 3}, AlN, SiC and Si{sub 3}N{sub 4} were fast-neutron-irradiated up to a fluence of 3.9x10{sup 26} n/m{sup 2}, different irradiation conditions from the previous report specimens, in the CMIR-4 rig in the JOYO experimental fast reactor in JNC. The following observations were performed: (1) Microstructural observation by means of transmission electron microscopy, (2) Measurement of swelling, (3) Measurement of thermal diffusivity by a laser-flash method, (4) Recovery of swelling by isochronal annealing, and (5) Recovery of thermal diffusivity by isochronal annealing. Obtained main results are summarized as follows. Macroscopic length changes by neutron irradiation of Al{sub 2}O{sub 3} and AlN were measured to be 1.8-2.0% and these of SiC and Si{sub 3}N{sub 4} to be 0.2-0.4%, respectively. Thermal diffusivities of all irradiated materials degraded to 0.03-0.05 cm{sup 2}/s, irrespective of materials which had large difference before irradiation. Microstructural observation of irradiated materials by TEM revealed that Al{sub 2}O{sub 3} contained high-density loops, microvoids in grains, and microcracking along grain boundaries, AlN contained high-density loops and microcracking along grain boundaries, SiC contained high-density loops, and Si{sub 3}N{sub 4} contained loops lying on the planes parallel to the c-axis, respectively. Macroscopic length of Al{sub 2}O{sub 3} and AlN started to recover at around 800deg or 1100degC, respectively, irrespective of irradiation temperature, and reduced quickly. Macroscopic length of SiC recovered gradually from near the irradiation temperature

  19. Protecting Intestinal Epithelial Cell Number 6 against Fission Neutron Irradiation through NF-κB Signaling Pathway

    Science.gov (United States)

    Chang, Gong-Min; Gao, Ya-Bing; Wang, Shui-Ming; Xu, Xin-Ping; Zhao, Li; Zhang, Jing; Li, Jin-Feng; Wang, Yun-Liang; Peng, Rui-Yun

    2015-01-01

    The purpose of this paper is to explore the change of NF-κB signaling pathway in intestinal epithelial cell induced by fission neutron irradiation and the influence of the PI3K/Akt pathway inhibitor LY294002. Three groups of IEC-6 cell lines were given: control group, neutron irradiation of 4Gy group, and neutron irradiation of 4Gy with LY294002 treatment group. Except the control group, the other groups were irradiated by neutron of 4Gy. LY294002 was given before 24 hours of neutron irradiation. At 6 h and 24 h after neutron irradiation, the morphologic changes, proliferation ability, apoptosis, and necrosis rates of the IEC-6 cell lines were assayed and the changes of NF-κB and PI3K/Akt pathway were detected. At 6 h and 24 h after neutron irradiation of 4Gy, the proliferation ability of the IEC-6 cells decreased and lots of apoptotic and necrotic cells were found. The injuries in LY294002 treatment and neutron irradiation group were more serious than those in control and neutron irradiation groups. The results suggest that IEC-6 cells were obviously damaged and induced serious apoptosis and necrosis by neutron irradiation of 4Gy; the NF-κB signaling pathway in IEC-6 was activated by neutron irradiation which could protect IEC-6 against injury by neutron irradiation; LY294002 could inhibit the activity of IEC-6 cells. PMID:25866755

  20. Protecting Intestinal Epithelial Cell Number 6 against Fission Neutron Irradiation through NF-κB Signaling Pathway

    Directory of Open Access Journals (Sweden)

    Gong-Min Chang

    2015-01-01

    Full Text Available The purpose of this paper is to explore the change of NF-κB signaling pathway in intestinal epithelial cell induced by fission neutron irradiation and the influence of the PI3K/Akt pathway inhibitor LY294002. Three groups of IEC-6 cell lines were given: control group, neutron irradiation of 4Gy group, and neutron irradiation of 4Gy with LY294002 treatment group. Except the control group, the other groups were irradiated by neutron of 4Gy. LY294002 was given before 24 hours of neutron irradiation. At 6 h and 24 h after neutron irradiation, the morphologic changes, proliferation ability, apoptosis, and necrosis rates of the IEC-6 cell lines were assayed and the changes of NF-κB and PI3K/Akt pathway were detected. At 6 h and 24 h after neutron irradiation of 4Gy, the proliferation ability of the IEC-6 cells decreased and lots of apoptotic and necrotic cells were found. The injuries in LY294002 treatment and neutron irradiation group were more serious than those in control and neutron irradiation groups. The results suggest that IEC-6 cells were obviously damaged and induced serious apoptosis and necrosis by neutron irradiation of 4Gy; the NF-κB signaling pathway in IEC-6 was activated by neutron irradiation which could protect IEC-6 against injury by neutron irradiation; LY294002 could inhibit the activity of IEC-6 cells.

  1. Microstructure and mechanical properties of neutron irradiated OFHC-copper before and after post-irradiation annealing

    DEFF Research Database (Denmark)

    Singh, B.N.; Edwards, D.J.; Toft, P.

    2001-01-01

    Tensile specimens of OFHC-copper were irradiated with fission neutrons in the DR-3 reactor at Risø National Laboratory at 100 deg. C to different displacement dose levels in the range of 0.01 to 0.3 dpa (NRT). Some of the specimens were tensile tested inthe as-irradiated condition at 100 deg. C...

  2. Fusion neutron irradiation of Ni(Si) alloys at high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Huang, J.S.; Guinan, M.W.; Hahn, P.A.

    1987-09-01

    Two Ni-4% Si alloys, with different cold work levels, are irradiated with 14 MeV fusion neutrons at 623 K, and their Curie temperatures are monitored during irradiation. The results are compared to those of an identical alloy irradiated by 2 MeV electrons. The results show that increasing dislocation density increases the Curie temperature change rate. At the same damage rate, the Curie temperature change rate for the alloy irradiated by 14 MeV fusion neutrons is only 6 to 7% of that for an identical alloy irradiated by 2 MeV electrons. It is well known that the migration of radiation induced defects contributes to segregation of silicon atoms at sinks in this alloy, causing the Curie temperature changes. The current results imply that the relative free defect production efficiency decreases from one for the electron irradiated sample to 6 to 7% for the fusion neutron irradiated sample. 17 refs., 4 figs., 1 tab.

  3. Quantitative TEM analysis of precipitation and grain boundary segregation in neutron irradiated EUROFER 97

    Science.gov (United States)

    Dethloff, Christian; Gaganidze, Ermile; Aktaa, Jarir

    2014-11-01

    Characterization of irradiation induced microstructural defects is essential for assessing the applicability of structural steels like the Reduced Activation Ferritic/Martensitic steel EUROFER 97 in upcoming fusion reactors. In this work Transmission Electron Microscopy (TEM) is used to analyze the types and structure of precipitates, and the evolution of their size distributions and densities caused by neutron irradiation to a dose of 32 displacements per atom (dpa) at 330-340 °C in the irradiation experiment ARBOR 1. A significant growth of MX and M23C6 type precipitates is observed after neutron irradiation, while the precipitate density remains unchanged. Hardening caused by MX and M23C6 precipitate growth is assessed by applying the Dispersed Barrier Hardening (DBH) model, and shown to be of minor importance when compared to other irradiation effects like dislocation loop formation. Additionally, grain boundary segregation of chromium induced by neutron irradiation was investigated and detected in irradiated specimens.

  4. Microstructure and mechanical behavior of neutron irradiated ultrafine grained ferritic steel

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad Alsabbagh; Apu Sarkar; Brandon Miller; Jatuporn Burns; Leah Squires; Douglas Porter; James I. Cole; K. L. Murty

    2014-10-01

    Neutron irradiation effects on ultra-fine grain (UFG) low carbon steel prepared by equal channel angular pressing (ECAP) has been examined. Counterpart samples with conventional grain (CG) sizes have been irradiated alongside with the UFG ones for comparison. Samples were irradiated in the Advanced Test Reactor (ATR) at Idaho National Laboratory (INL) to 1.24 dpa. Atom probe tomography revealed manganese, silicon-enriched clusters in both ECAP and CG steel after neutron irradiation. X-ray quantitative analysis showed that dislocation density in CG increased after irradiation. However, no significant change was observed in UFG steel revealing better radiation tolerance.

  5. Dislocation and void segregation in copper during neutron irradiation

    DEFF Research Database (Denmark)

    Singh, Bachu Narain; Leffers, Torben; Horsewell, Andy

    1986-01-01

    High-purity (99. 999%) and fully annealed copper specimens have been irradiated in the DR-3 reactor at Riso to doses of 1 multiplied by 10**2**2 and 5 multiplied by 10**2**2 neutrons (fast)m** minus **2(2 multiplied by 10** minus **3 dpa and 1 multiplied by 10** minus **2 dpa, respectively...... were distributed between these walls. The dislocation walls were practically free of voids and generally had a void-denuded zone along them. The density of dislocations (loops and segments) was very low in the region containing voids (i. e. between the dislocation walls). Even with this low dislocation...... density, the void swelling rate was very high (approximately 2. 5% per dpa). The implications of the segregated distribution of sinks for void formation and growth are briefly discussed....

  6. Optical studies of neutron-irradiated lithium hydride single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Oparin, D.V.; Pilipenko, G.I.; Tyutyunnik, O.I.; Gavrilov, F.F.; Sulimov, E.M. (Ural' skij Politekhnicheskij Inst., Sverdlovsk (USSR))

    1984-09-01

    Lithium hydride single crystals irradiated with neutrons were studied by the optical method. Wide bands belonging to the large F-aggregate and quasimetallic F-centres and to the metallic lithium colloids were discovered in the absorption spectra at room temperature. The small Fsub(n)-centres and molecular lithium centres were detected at 77 K. From the electron-vibrational structure of the absorption spectra of these centres the energies of acoustic phonons in X, W, L points of the Brillouin zone of lithium hydride have been found out: TA(L)-235 cm/sup -1/, TA(X)-27g cm/sup -1/, TA(W)-327 cm/sup -1/, LA(W)-384 cm/sup -1/, LA(X)-426 cm/sup -1/.

  7. Kinetic Monte Carlo modelling of neutron irradiation damage in iron

    Energy Technology Data Exchange (ETDEWEB)

    Gamez, L. [Instituto de Fusion Nuclear, UPM, Madrid (Spain); Departamento de Fisica Aplicada, ETSII, UPM, Madrid (Spain)], E-mail: linarejos.gamez@upm.es; Martinez, E. [Instituto de Fusion Nuclear, UPM, Madrid (Spain); Lawrence Livermore National Laboratory, LLNL, CA 94550 (United States); Perlado, J.M.; Cepas, P. [Instituto de Fusion Nuclear, UPM, Madrid (Spain); Caturla, M.J. [Departamento de Fisica Aplicada, Universidad de Alicante, Alicante (Spain); Victoria, M. [Instituto de Fusion Nuclear, UPM, Madrid (Spain); Marian, J. [Lawrence Livermore National Laboratory, LLNL, CA 94550 (United States); Arevalo, C. [Instituto de Fusion Nuclear, UPM, Madrid (Spain); Hernandez, M.; Gomez, D. [CIEMAT, Madrid (Spain)

    2007-10-15

    Ferritic steels (FeCr based alloys) are key materials needed to fulfill the requirements expected in future nuclear fusion facilities, both for magnetic and inertial confinement, and advanced fission reactors (GIV) and transmutation systems. Research in such field is actually a critical aspect in the European research program and abroad. Experimental and multiscale simulation methodologies are going hand by hand in increasing the knowledge of materials performance. At DENIM, it is progressing in some specific part of the well-linked simulation methodology both for defects energetics and diffusion, and for dislocation dynamics. In this study, results obtained from kinetic Monte Carlo simulations of neutron irradiated Fe under different conditions are presented, using modified ad hoc parameters. A significant agreement with experimental measurements has been found for some of the parameterization and mechanisms considered. The results of these simulations are discussed and compared with previous calculations.

  8. Final report on graphite irradiation test OG-3. [Fast neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Price, R.J.; Beavan, L.A.

    1977-01-01

    The results of dimensional, thermal expansivity, thermal conductivity, Young's modulus, and tensile strength measurements on graphite specimens irradiated in capsule OG-3 are presented. The graphite grades investigated included near-isotropic H-451 (three different preproduction lots), TS-1240, and SO818; needle coke H-327; and European coal tar pitch coke grades P/sub 3/JHA/sub 2/N, P/sub 3/JHAN, and ASI2-500. Data were obtained in the temperature range 823/sup 0/K to 1673/sup 0/K. The peak fast neutron fluence in the experiment was 3 x 10/sup 25/ n/m/sup 3/ (E greater than 29 fJ)/sub HTGR/; the total accumulated fluence exceeded 9 x 10/sup 25/ n/m/sup 2/ on some H-451 specimens and 6 x 10/sup 25/ n/m/sup 2/ on some TS-1240 specimens. Irradiation-induced dimensional changes on H-451 graphite differed slightly from earlier predictions. For an irradiation temperature of about 1225/sup 0/K, axial shrinkage rates at high fluences were somewhat higher than predicted, and the fluence at which radial expansion started (about 9 x 10/sup 25/ n/m/sup 2/ at 1275/sup 0/K) was lower. TS-1240 graphite underwent smaller dimensional changes than H-451 graphite, while limited data on SO818 and ASI2-500 graphites showed similar behavior to H-451. P/sub 3/JHAN and P/sub 3/JHA/sub 2/N graphites displayed anisotropic behavior with rapid axial shrinkage. Comparison of dimensional changes between specimens from three logs of H-451 and of TS-1240 graphites showed no significant log-to-log variations for H-451, and small but significant log-to-log variations for TS-1240. The thermal expansivity of the near-isotropic graphites irradiated at 865-1045/sup 0/K first increased by 5 percent to 10 percent and then decreased. At higher irradiation temperatures the thermal expansivity decreased by up to 50 percent. Changes in thermal conductivity were consistent with previously established curves. Specimens which were successively irradiated at two different temperatures took on the

  9. Microstructural evolution in fast-neutron-irradiated austenitic stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Stoller, R.E.

    1987-12-01

    The present work has focused on the specific problem of fast-neutron-induced radiation damage to austenitic stainless steels. These steels are used as structural materials in current fast fission reactors and are proposed for use in future fusion reactors. Two primary components of the radiation damage are atomic displacements (in units of displacements per atom, or dpa) and the generation of helium by nuclear transmutation reactions. The radiation environment can be characterized by the ratio of helium to displacement production, the so-called He/dpa ratio. Radiation damage is evidenced microscopically by a complex microstructural evolution and macroscopically by density changes and altered mechanical properties. The purpose of this work was to provide additional understanding about mechanisms that determine microstructural evolution in current fast reactor environments and to identify the sensitivity of this evolution to changes in the He/dpa ratio. This latter sensitivity is of interest because the He/dpa ratio in a fusion reactor first wall will be about 30 times that in fast reactor fuel cladding. The approach followed in the present work was to use a combination of theoretical and experimental analysis. The experimental component of the work primarily involved the examination by transmission electron microscopy of specimens of a model austenitic alloy that had been irradiated in the Oak Ridge Research Reactor. A major aspect of the theoretical work was the development of a comprehensive model of microstructural evolution. This included explicit models for the evolution of the major extended defects observed in neutron irradiated steels: cavities, Frank faulted loops and the dislocation network. 340 refs., 95 figs., 18 tabs.

  10. Preparation and Purification of 125I With Neutron Irradiated Xenon in a Vacuum Circular system

    Institute of Scientific and Technical Information of China (English)

    MIAOZeng-xing; LIYu-cheng; YUNing-wen; WUJie; XIANGXue-qin; ZHAOXiu-yan

    2003-01-01

    This paper describes the preparation and purification of 125I with neutron irradiated xenon in a vacuum circular system, which is specially designed with an irradiate chamber set inside of the reactor and three decay chambers set outside of the reactor. The xenon is filled in this system and recurrently circulates between the irradiate chamber and the decay chambers during the reactor is operating.

  11. Resistivity measurements on the neutron irradiated detector grade silicon materials

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zheng

    1993-11-01

    Resistivity measurements under the condition of no or low electrical field (electrical neutral bulk or ENB condition) have been made on various device configurations on detector grade silicon materials after neutron irradiation. Results of the measurements have shown that the ENB resistivity increases with neutron fluence ({Phi}{sub n}) at low {phi}{sub n} (<10{sup 13} n/cm{sup 2}) and saturates at a value between 300 and 400 k{Omega}-cm at {phi}{sub n} {approximately}10{sup 13} n/cm{sup 2}. Meanwhile, the effective doping concentration N{sub eff} in the space charge region (SCR) obtained from the C-V measurements of fully depleted p{sup +}/n silicon junction detectors has been found to increase nearly linearly with {phi}{sub n} at high fluences ({phi}{sub n} > 10{sup 13} n/cm{sup 2}). The experimental results are explained by the deep levels crossing the Fermi level in the SCR and near perfect compensation in the ENB by all deep levels, resulting in N{sub eff} (SCR) {ne} n or p (free carrier concentrations in the ENB).

  12. Resistivity measurements on the neutron irradiated detector grade silicon materials

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zheng

    1993-11-01

    Resistivity measurements under the condition of no or low electrical field (electrical neutral bulk or ENB condition) have been made on various device configurations on detector grade silicon materials after neutron irradiation. Results of the measurements have shown that the ENB resistivity increases with neutron fluence ({Phi}{sub n}) at low {phi}{sub n} (<10{sup 13} n/cm{sup 2}) and saturates at a value between 300 and 400 k{Omega}-cm at {phi}{sub n} {approximately}10{sup 13} n/cm{sup 2}. Meanwhile, the effective doping concentration N{sub eff} in the space charge region (SCR) obtained from the C-V measurements of fully depleted p{sup +}/n silicon junction detectors has been found to increase nearly linearly with {phi}{sub n} at high fluences ({phi}{sub n} > 10{sup 13} n/cm{sup 2}). The experimental results are explained by the deep levels crossing the Fermi level in the SCR and near perfect compensation in the ENB by all deep levels, resulting in N{sub eff} (SCR) {ne} n or p (free carrier concentrations in the ENB).

  13. Effect of neutron irradiation on fracture toughness of metal matrix composites

    Science.gov (United States)

    Sato, Shinji; Hamada, Kenichi; Kohyama, Akira

    1992-09-01

    Based on the recent improvement in mechanical properties of unidirectionally reinforced metal matrix composites (MMCs), SiC/Al and C/Al, impact property change due to neutron irradiation has been investigated. This paper details effects of neutron irradiation on fracture toughness of the MMCs. Materials used were formed sheets of SiC/Al and C/Al. Miniaturized Charpy V-notched specimens were tested by an instrumented Charpy impact tester. Neutron irradiation was performed in JMTR(LWR) at Oarai. The Charpy value was increased with increasing test temperature and with neutron irradiation. SiC/Al was rather more neutron fluence insensitive than C/Al and the insensitivity was correlated to differences in interfacial structure between the two systems.

  14. Effect of neutron irradiation on the microstructure of tungsten

    Directory of Open Access Journals (Sweden)

    M. Klimenkov

    2016-12-01

    Full Text Available Two grades of pure tungsten, single and polycrystalline, were irradiated for 282 days in the HFR reactor, Petten, at 900 °C to an average damage level of 1.6dpa. Each grade of tungsten was investigated using the transmission electron microscope (TEM to assess the effect of neutron irradiation on tungsten microstructure. Investigations revealed the formation of faceted cavities, whose diameter varies from 4 to 14nm in both materials. The cavities are homogeneously distributed only inside single crystalline tungsten. The local distribution of cavities in polycrystalline tungsten is strongly influenced by grain boundaries. The number densities of cavities were measured to be 4×1021 m−3 for polycrystalline and 2.5×1021 m−3 for single crystalline tungsten. This corresponds to volumetric densities of 0.45% and 0.33% respectively. High-resolution transmission electron microscopy (HRTEM revealed that faces of cavities are oriented in (110 plane. Analytical investigations showed precipitation of rhenium and osmium produced by a transmutation reaction around cavities and at grain boundaries.

  15. Development of IASCC Test Facility for Neutron-irradiated Materials

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S. W.; Kim, D. J.; Hwang, S. S. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    From literature review and benchmark studies on recent technologies for IASCC evaluation of highly irradiated stainless steels, the requirements to establish IASCC test facility were drawn. According to the requirements, IASCC test facility for assessment of life time and integrity of RVIs in Korean PWRs will be designed in detail and constructed in hot cells of KAERI. Irradiation assisted stress corrosion cracking (IASCC) has been regarded as the main cause for intergranular cracking incidents in reactor vessel internals (RVIs) in light water reactors (LWRs). IASCC was reported in a fuel rod in the 1960s, a control rod in the 1970s, and a baffle former bolt in recent years. For a proactive management of IASCC of these components, a lot of work has been performed in boiling water reactors (BWRs). From these works, IASCC mechanism and its relation to radiation-induced segregation (RIS), neutron fluence, and applied stress were proposed to describe IASCC behavior of RVIs in BWRs. However, the IASCC mechanism of RVIs in pressurized water reactors (PWRs) is not fully understood yet as compared with that in BWRs owing to a lack of reliable data. Recently, worldwide efforts have been made to investigate the IASCC susceptibility of RVIs in PWRs.

  16. Neutron energy spectrum influence on irradiation hardening and microstructural development of tungsten

    Science.gov (United States)

    Fukuda, Makoto; Kiran Kumar, N. A. P.; Koyanagi, Takaaki; Garrison, Lauren M.; Snead, Lance L.; Katoh, Yutai; Hasegawa, Akira

    2016-10-01

    Neutron irradiation to single crystal pure tungsten was performed in the mixed spectrum High Flux Isotope Reactor (HFIR). To investigate the influences of neutron energy spectrum, the microstructure and irradiation hardening were compared with previous data obtained from the irradiation campaigns in the mixed spectrum Japan Material Testing Reactor (JMTR) and the sodium-cooled fast reactor Joyo. The irradiation temperatures were in the range of ∼90-∼800 °C and fast neutron fluences were 0.02-9.00 × 1025 n/m2 (E > 0.1 MeV). Post irradiation evaluation included Vickers hardness measurements and transmission electron microscopy. The hardness and microstructure changes exhibited a clear dependence on the neutron energy spectrum. The hardness appeared to increase with increasing thermal neutron flux when fast fluence exceeds 1 × 1025 n/m2 (E > 0.1 MeV). Irradiation induced precipitates considered to be χ- and σ-phases were observed in samples irradiated to >1 × 1025 n/m2 (E > 0.1 MeV), which were pronounced at high dose and due to the very high thermal neutron flux of HFIR. Although the irradiation hardening mainly caused by defects clusters in a low dose regime, the transmutation-induced precipitation appeared to impose additional significant hardening of the tungsten.

  17. Irradiation tests of ITER candidate Hall sensors using two types of neutron spectra.

    Science.gov (United States)

    Ďuran, I; Bolshakova, I; Viererbl, L; Sentkerestiová, J; Holyaka, R; Lahodová, Z; Bém, P

    2010-10-01

    We report on irradiation tests of InSb based Hall sensors at two irradiation facilities with two distinct types of neutron spectra. One was a fission reactor neutron spectrum with a significant presence of thermal neutrons, while another one was purely fast neutron field. Total neutron fluence of the order of 10(16) cm(-2) was accumulated in both cases, leading to significant drop of Hall sensor sensitivity in case of fission reactor spectrum, while stable performance was observed at purely fast neutron spectrum. This finding suggests that performance of this particular type of Hall sensors is governed dominantly by transmutation. Additionally, it further stresses the need to test ITER candidate Hall sensors under neutron flux with ITER relevant spectrum.

  18. Migration and accumulation at dislocations of transmutation helium in austenitic steels upon neutron irradiation

    Science.gov (United States)

    Kozlov, A. V.; Portnykh, I. A.

    2016-04-01

    The model of the migration and accumulation at dislocations of transmutation helium and the formation of helium-vacancy pore nuclei in austenitic steels upon neutron irradiation has been proposed. As illustrations of its application, the dependences of the characteristics of pore nuclei on the temperature of neutron irradiation have been calculated. The results of the calculations have been compared with the experimental data in the literature on measuring the characteristics of radiation-induced porosity that arises upon the irradiation of shells of fuel elements of a 16Cr-19Ni-2Mo-2Mn-Si-Ti-Nb-V-B steel in a fast BN600 neutron reactor at different temperatures.

  19. Characterization of the neutron irradiation system for use in the Low-Dose-Rate Irradiation Facility at Sandia National Laboratories.

    Energy Technology Data Exchange (ETDEWEB)

    Franco, Manuel [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-08-01

    The objective of this work was to characterize the neutron irradiation system consisting of americium-241 beryllium (241AmBe) neutron sources placed in a polyethylene shielding for use at Sandia National Laboratories (SNL) Low Dose Rate Irradiation Facility (LDRIF). With a total activity of 0.3 TBq (9 Ci), the source consisted of three recycled 241AmBe sources of different activities that had been combined into a single source. The source in its polyethylene shielding will be used in neutron irradiation testing of components. The characterization of the source-shielding system was necessary to evaluate the radiation environment for future experiments. Characterization of the source was also necessary because the documentation for the three component sources and their relative alignment within the Special Form Capsule (SFC) was inadequate. The system consisting of the source and shielding was modeled using Monte Carlo N-Particle transport code (MCNP). The model was validated by benchmarking it against measurements using multiple techniques. To characterize the radiation fields over the full spatial geometry of the irradiation system, it was necessary to use a number of instruments of varying sensitivities. First, the computed photon radiography assisted in determining orientation of the component sources. With the capsule properly oriented inside the shielding, the neutron spectra were measured using a variety of techniques. A N-probe Microspec and a neutron Bubble Dosimeter Spectrometer (BDS) set were used to characterize the neutron spectra/field in several locations. In the third technique, neutron foil activation was used to ascertain the neutron spectra. A high purity germanium (HPGe) detector was used to characterize the photon spectrum. The experimentally measured spectra and the MCNP results compared well. Once the MCNP model was validated to an adequate level of confidence, parametric analyses was performed on the model to optimize for potential

  20. Viability of the ESS-Bilbao neutron source for irradiation of nuclear fusion materials

    Science.gov (United States)

    Páramo, A. R.; Sordo, F.; Perlado, J. M.; Rivera, A.

    2014-01-01

    The ESS-Bilbao neutron source, currently under construction, is conceived as a multipurpose facility. It will offer a fast neutron beam line for materials irradiation. In this paper we discuss the viability of ESS-Bilbao for experimental studies of fusion materials. Making use of the already designed target station we have calculated the neutron spectrum expected in the fast neutron line. Then, we have studied the neutron irradiation effects in two model materials: iron and silica. We have calculated the expected PKA (primary knock-on atom) spectra and light species production as well as the damage production in these materials. Regarding structural materials, we conclude that the ESS-Bilbao neutron irradiation facility will play a minor role due to the resulting low neutron fluxes (about two orders of magnitude lower than in fusion reactors). On the other hand, ESS-Bilbao turns out to be relevant for studies of final lenses in laser fusion power plants. A comparison with the conditions expected for HiPER final lenses shows that the fluxes will be only a factor 5 smaller in ESS-Bilbao and the PKA spectra will be very similar. Taking into account, in addition, that relevant effects on lenses occur from the onset of irradiation, we conclude that an appropriate irradiation cell with in situ characterisation techniques will make ESS-Bilbao very attractive for applied neutron damage studies of laser fusion final lenses. Finally, we compare ESS-Bilbao with other facilities.

  1. Displacement damage and transmutations in metals under neutron and proton irradiation; Dommage de deplacements et transmutations dans les metaux sous irradiation de neutrons et de protons

    Energy Technology Data Exchange (ETDEWEB)

    Vladimirov, P. [FZK, Institute of Materials Research I, Karlsruhe (Germany); Bouffard, S. [CEA/DRECAM, Centre interdisciplinaire de recherche ions lasers (CIRIL), 14 - Caen (France)

    2008-04-15

    The knowledge of the defect and impurity generation rates, as well as the defect spatial distribution, is the corner stone for the understanding of the evolution of material properties under irradiation. This knowledge is also an essential element for comprehensive experimental simulations of the behavior of irradiated materials. In this article the interaction of neutron and proton irradiation with metals is discussed with respect to displacement damage production. Charged particle irradiation is also briefly illustrated. After discussion of the primary interaction of projectiles (neutrons, charged particles in general, and protons in particular) with target atoms/nuclei, we describe the interaction of a recoil atom with other target atoms resulting in the slowing down of the projectile, displacement damage, impurity atom production due to nuclear reactions, and the creation of atomic displacement cascades. Then the further evolution of defect structure is discussed. The next section, devoted to sub-cascade formation, is divided into two parts. The first experimental evidence of sub-cascade formation under neutron and charged particle irradiation is presented. Then the models of sub-cascade formation are described. Finally we review the models for the calculation of displacement damage and show how these models can be applied to displacement damage calculation under neutron irradiation with a demonstration of a real application of the methods discussed to several nuclear facilities. (authors)

  2. Formation of austenite in high Cr ferritic/martensitic steels by high fluence neutron irradiation

    Science.gov (United States)

    Lu, Z.; Faulkner, R. G.; Morgan, T. S.

    2008-12-01

    High Cr ferritic/martensitic steels are leading candidates for structural components of future fusion reactors and new generation fission reactors due to their excellent swelling resistance and thermal properties. A commercial grade 12%CrMoVNb ferritic/martensitic stainless steel in the form of parent plate and off-normal weld materials was fast neutron irradiated up to 33 dpa (1.1 × 10 -6 dpa/s) at 400 °C and 28 dpa (1.7 × 10 -6 dpa/s) at 465 °C, respectively. TEM investigation shows that the fully martensitic weld metal transformed to a duplex austenite/ferrite structure due to high fluence neutron irradiation, the austenite was heavily voided (˜15 vol.%) and the ferrite was relatively void-free; whilst no austenite phases were detected in plate steel. Thermodynamic and phase equilibria software MTDATA has been employed for the first time to investigate neutron irradiation-induced phase transformations. The neutron irradiation effect is introduced by adding additional Gibbs free energy into the system. This additional energy is produced by high energy neutron irradiation and can be estimated from the increased dislocation loop density caused by irradiation. Modelling results show that neutron irradiation reduces the ferrite/austenite transformation temperature, especially for high Ni weld metal. The calculated results exhibit good agreement with experimental observation.

  3. Formation of austenite in high Cr ferritic/martensitic steels by high fluence neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Z. [IPTME, Loughborough University, Loughborough LE11 3U (United Kingdom)], E-mail: zheng.lu@lboro.ac.uk; Faulkner, R.G.; Morgan, T.S. [IPTME, Loughborough University, Loughborough LE11 3U (United Kingdom)

    2008-12-01

    High Cr ferritic/martensitic steels are leading candidates for structural components of future fusion reactors and new generation fission reactors due to their excellent swelling resistance and thermal properties. A commercial grade 12%CrMoVNb ferritic/martensitic stainless steel in the form of parent plate and off-normal weld materials was fast neutron irradiated up to 33 dpa (1.1 x 10{sup -6} dpa/s) at 400 deg. C and 28 dpa (1.7 x 10{sup -6} dpa/s) at 465 deg. C, respectively. TEM investigation shows that the fully martensitic weld metal transformed to a duplex austenite/ferrite structure due to high fluence neutron irradiation, the austenite was heavily voided ({approx}15 vol.%) and the ferrite was relatively void-free; whilst no austenite phases were detected in plate steel. Thermodynamic and phase equilibria software MTDATA has been employed for the first time to investigate neutron irradiation-induced phase transformations. The neutron irradiation effect is introduced by adding additional Gibbs free energy into the system. This additional energy is produced by high energy neutron irradiation and can be estimated from the increased dislocation loop density caused by irradiation. Modelling results show that neutron irradiation reduces the ferrite/austenite transformation temperature, especially for high Ni weld metal. The calculated results exhibit good agreement with experimental observation.

  4. Resistivity damage rates in fusion-neutron-irradiated metals at 4. 2 K

    Energy Technology Data Exchange (ETDEWEB)

    Guinan, M.W.; Kinney, J.H.

    1981-01-01

    Changes in electrical resistivity at liquid helium temperature have been used to monitor the production of damage in dilute alloys of vanadium, niobium and molybdenum, and pure tungsten, aluminum and copper irradiated with high energy neutrons. The neutrons were produced at the Livermore rotating-target neutron sources (RTNS-I and RTNS-II). Further experiments on V, Nb and Mo were carried out with 30 MeV d-Be neutrons and slightly degraded fission-spectra neutrons. The results for all six materials are compared to those obtained in a pure fission spectrum. The relative damage production rates are in agreement with predictions based on damage energy calculations.

  5. In Vitro antileishmanial properties of neutron-irradiated meglumine antimoniate

    Directory of Open Access Journals (Sweden)

    Samanta Etel Treiger Borborema

    2005-10-01

    Full Text Available Pentavalent antimony, as meglumine antimoniate (Glucantime® or sodium stibogluconate (Pentostam® , is the main treatment for leishmaniasis, a complex of diseases caused by the protozoan Leishmania, and an endemic and neglected threat in Brazil. Despite over half a century of clinical use, their mechanism of action, toxicity and pharmacokinetic data remain unknown. The analytical methods for determination of antimony in biological systems remain complex and have low sensitivity. Radiotracer studies have a potential in pharmaceutical development. The aim of this study was to obtain a radiotracer for antimony, with suitable physical and biological properties. Meglumine antimoniate was neutron irradiated inside the IEA-R1 nuclear reactor, producing two radioisotopes 122Sb and 124Sb, with high radionuclidic purity and good specific activity. This compound showed the same antileishmanial activity as the native compound. The use of the radiotracers, easily created by neutron irradiation, could be an interesting tool to solve important questions in antimonial pharmacology.Os antimoniais pentavalentes, como o antimoniato de meglumina (Glucantime® ou estibogluconato de sódio (Pentostam® , são o principal tratamento para a leishmaniose, um complexo de doenças causadas pelo protozoário parasita Leishmania, uma doença endêmica e negligenciada no Brasil. Apesar do seu uso clínico por mais de meio século, seu mecanismo de ação, toxicidade e dados de farmacocinética permanecem desconhecidos. Os métodos analíticos para determinação de antimônio em sistemas biológicos são complexos e apresentam baixa sensibilidade. Estudos utilizando radiotraçadores têm papel potencial no desenvolvimento farmacológico. O objetivo deste estudo foi desenvolver um radiotraçador de antimônio, com propriedades físicas e biológicas adequadas. O antimoniato de meglumina foi irradiado por nêutrons no reator nuclear IEA-R1, produzindo dois radioisótopos: 122

  6. Evaluation of neutronic characteristic of irradiation field in MEU6-core. Comparison of neutron flux and neutron spectrum in MEU6-core and Mixed-core

    Energy Technology Data Exchange (ETDEWEB)

    Nagao, Yoshiharu; Komukai, Bunsaku; Tabata, Toshio; Takeda, Takashi; Fujiki, Kazuo [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment

    1999-08-01

    In JMTR (Japan Materials Testing Reactor, 50 MW), the core configuration has been changed from previously employed Mixed-core (25 LEUs(low enrichment uranium (19.8%) fuel elements) and 2 MEUs (medium enrichment uranium (45%) fuel elements)) to MEU6-core (21 LEUs and 6 MEUs), since 125th operating cycle (started in Nov. 17, 1998). In order to investigate the effect of core configuration change on the irradiation tests, neutron flux distribution and neutron spectrum of irradiation field in MEU6-core were calculated by diffusion code CITATION and Monte Carlo code MCNP. As the result, it was confirmed that irradiation field in the MEU6-core has the neutronic characteristics almost equivalent to the irradiation field in the Mixed-core. (author)

  7. Neutron dosimetry and damage calculations for the EBRII COBRA-1A irradiations

    Energy Technology Data Exchange (ETDEWEB)

    Greenwood, L.R.; Ratner, R.T. [Pacific Northwest National Lab., Richland, WA (United States)

    1997-04-01

    Neutron fluence measurements and radiation damage calculations are reported for the joint U.S. and Japanese COBRA-1A1 and 1A2 irradiations in the Experimental Breeder Reactor II. The maximum total neutron fluences at midplane were 2.0E+22 and 7.5E+22 n/cm{sup 2}, for the 1A1 and 1A2 irradiations, respectively, resulting in about 8.0 and 30.3 dpa in stainless steel.

  8. Deuterium Depth Profile in Neutron-Irradiated Tungsten Exposed to Plasma

    Energy Technology Data Exchange (ETDEWEB)

    Masashi Shimada; G. Cao; Y. Hatano; T. Oda; Y. Oya; M. Hara; P. Calderoni

    2011-05-01

    The effect of radiation damage has been mainly simulated using high-energy ion bombardment. The ions, however, are limited in range to only a few microns into the surface. Hence, some uncertainty remains about the increase of trapping at radiation damage produced by 14 MeV fusion neutrons, which penetrate much farther into the bulk material. With the Japan-US joint research project: Tritium, Irradiations, and Thermofluids for America and Nippon (TITAN), the tungsten samples (99.99 % pure from A.L.M.T., 6mm in diameter, 0.2mm in thickness) were irradiated to high flux neutrons at 50 C and to 0.025 dpa in the High Flux Isotope Reactor (HFIR) at the Oak Ridge National Laboratory (ORNL). Subsequently, the neutron-irradiated tungsten samples were exposed to a high-flux deuterium plasma (ion flux: 1021-1022 m-2s-1, ion fluence: 1025-1026 m-2) in the Tritium Plasma Experiment (TPE) at the Idaho National Laboratory (INL). First results of deuterium retention in neutron-irradiated tungsten exposed in TPE have been reported previously. This paper presents the latest results in our on-going work of deuterium depth profiling in neutron-irradiated tungsten via nuclear reaction analysis. The experimental data is compared with the result from non neutron-irradiated tungsten, and is analyzed with the Tritium Migration Analysis Program (TMAP) to elucidate the hydrogen isotope behavior such as retention and depth distribution in neutron-irradiated and non neutron-irradiated tungsten.

  9. Embrittlement of low copper VVER 440 surveillance samples neutron-irradiated to high fluences

    Science.gov (United States)

    Miller, M. K.; Russell, K. F.; Kocik, J.; Keilova, E.

    2000-11-01

    An atom probe tomography microstructural characterization of low copper (0.06 at.% Cu) surveillance samples from a VVER 440 reactor has revealed manganese and silicon segregation to dislocations and other ultrafine features in neutron-irradiated base and weld materials (fluences 1×10 25 m-2 and 5×10 24 m-2, E>0.5 MeV, respectively). The results indicate that there is an additional mechanism of embrittlement during neutron irradiation that manifests itself at high fluences.

  10. Identification of neutron irradiation induced strain rate sensitivity change using inverse FEM analysis of Charpy test

    Science.gov (United States)

    Haušild, Petr; Materna, Aleš; Kytka, Miloš

    2015-04-01

    A simple methodology how to obtain additional information about the mechanical behaviour of neutron-irradiated WWER 440 reactor pressure vessel steel was developed. Using inverse identification, the instrumented Charpy test data records were compared with the finite element computations in order to estimate the strain rate sensitivity of 15Ch2MFA steel irradiated with different neutron fluences. The results are interpreted in terms of activation volume change.

  11. Low-temperature embrittlement and fracture of metals with different crystal lattices – Dislocation mechanisms

    Directory of Open Access Journals (Sweden)

    V.M. Chernov

    2016-12-01

    Full Text Available The state of a low-temperature embrittlement (cold brittleness and dislocation mechanisms for formation of the temperature of a ductile-brittle transition and brittle fracture of metals (mono- and polycrystals with various crystal lattices (BCC, FCC, HCP are considered. The conditions for their formation connected with a stress-deformed state and strength (low temperature yield strength as well as the fracture breaking stress and mobility of dislocations in the top of a crack of the fractured metal are determined. These conditions can be met for BCC and some HCP metals in the initial state (without irradiation and after a low-temperature damaging (neutron irradiation. These conditions are not met for FCC and many HCP metals. In the process of the damaging (neutron irradiation such conditions are not met also and the state of low-temperature embrittlement of metals is absent (suppressed due to arising various radiation dynamic processes, which increase the mobility of dislocations and worsen the strength characteristics.

  12. Low temperature asphalt mixtures

    OpenAIRE

    Modrijan, Damjan

    2006-01-01

    This thesis presents the problem of manufacturing and building in the asphalt mixtures produced by the classical hot procedure and the possibility of manufacturing low temperature asphalt mixtures.We will see the main advantages of low temperature asphalt mixtures prepared with bitumen with organic addition Sasobit and compare it to the classical asphalt mixtures. The advantages and disadvantages of that are valued in the practical example in the conclusion.

  13. Low temperature creep plasticity

    Directory of Open Access Journals (Sweden)

    Michael E. Kassner

    2014-07-01

    Full Text Available The creep behavior of crystalline materials at low temperatures (T < 0.3Tm is discussed. In particular, the phenomenological relationships that describe primary creep are reviewed and analyzed. A discussion of the activation energy for creep at T < 0.3Tm is discussed in terms of the context of higher temperature activation energy. The basic mechanism(s of low temperature creep plasticity are discussed, as well.

  14. Effect of neutron irradiation on the mechanical properties of weld overlay cladding for reactor pressure vessel

    Science.gov (United States)

    Tobita, Tohru; Udagawa, Makoto; Chimi, Yasuhiro; Nishiyama, Yutaka; Onizawa, Kunio

    2014-09-01

    This study investigates the effects of high fluence neutron irradiation on the mechanical properties of two types of cladding materials fabricated using the submerged-arc welding and electroslag welding methods. The tensile tests, Charpy impact tests, and fracture toughness tests were conducted before and after the neutron irradiation with a fluence of 1 × 1024 n/m2 at 290 °C. With neutron irradiation, we could observe an increase in the yield strength and ultimate strength, and a decrease in the total elongation. All cladding materials exhibited ductile-to-brittle transition behavior during the Charpy impact tests. A reduction in the Charpy upper-shelf energy and an increase in the ductile-to-brittle transition temperature was observed with neutron irradiation. There was no obvious decrease in the elastic-plastic fracture toughness (JIc) of the cladding materials upon irradiation with high neutron fluence. The tearing modulus was found to decrease with neutron irradiation; the submerged-arc-welded cladding materials exhibited low JIc values at high temperatures.

  15. Effect of neutron irradiation on the mechanical properties of weld overlay cladding for reactor pressure vessel

    Energy Technology Data Exchange (ETDEWEB)

    Tobita, Tohru, E-mail: tobita.tohru@jaea.go.jp; Udagawa, Makoto; Chimi, Yasuhiro; Nishiyama, Yutaka; Onizawa, Kunio

    2014-09-15

    This study investigates the effects of high fluence neutron irradiation on the mechanical properties of two types of cladding materials fabricated using the submerged-arc welding and electroslag welding methods. The tensile tests, Charpy impact tests, and fracture toughness tests were conducted before and after the neutron irradiation with a fluence of 1 × 10{sup 24} n/m{sup 2} at 290 °C. With neutron irradiation, we could observe an increase in the yield strength and ultimate strength, and a decrease in the total elongation. All cladding materials exhibited ductile-to-brittle transition behavior during the Charpy impact tests. A reduction in the Charpy upper-shelf energy and an increase in the ductile-to-brittle transition temperature was observed with neutron irradiation. There was no obvious decrease in the elastic–plastic fracture toughness (J{sub Ic}) of the cladding materials upon irradiation with high neutron fluence. The tearing modulus was found to decrease with neutron irradiation; the submerged-arc-welded cladding materials exhibited low J{sub Ic} values at high temperatures.

  16. Neutron Irradiation Tests of Pressure Transducers in Liquid Helium

    CERN Document Server

    Amand, J F; Casas-Cubillos, J; Thermeau, J P

    1999-01-01

    The superconducting magnets of the future Large Hadron Collider (LHC) at CERN will operate in pressurised superfluid helium (1 bar, 1.9 K). About 500 pressure transducers will be placed in the liquid helium bath for monitoring the filling and the pressure transients after resistive transitions. Their precision must remain better than 100 mbar at pressures below 2 bar and better than 5% for higher pressures (up to 20 bar), with temperatures ranging from 1.8 K to 300 K. All the tested transducers are based on the same principle: the fluid or gas is separated from a sealed reference vacuum by an elastic membrane; its deformation indicates the pressure. The transducers will be exposed to high neutron fluence (2 kGy, 1014 n/cm2 per year) during the 20 years of machine operation. This irradiation may induce changes both on the membranes characteristics (leakage, modification of elasticity) and on gauges which measure their deformations. To investigate these effects and select the transducer to be used in the LHC, a...

  17. Analysis of microstress in neutron irradiated polyester fibre by X-ray diffraction technique

    Indian Academy of Sciences (India)

    B Mallick; R C Behera; T Patel

    2005-10-01

    Microstresses developed in the crystallites of polymeric material due to irradiation of high-energy particle causes peak broadening and shifting of X-ray diffraction lines to lower angle. Neutron irradiation significantly changes the material properties by displacement of lattice atoms and the generation of helium and hydrogen by nuclear transmutation. Another important aspect of neutron irradiation is that the fast neutron can produce dense ionization at deep levels in the materials. The polyethylene terephthalate (PET) fibre of raw denier value, 78.2, were irradiated by fast neutron of energy, 4.44 MeV, at different fluences ranging from 1 × 109 n/cm2 to 1 × 1012 n/cm2. In the present work, the radiation heating microstresses developed in PET micro-crystallites was investigated applying X’Pert-MPD Philips Analytical X-ray diffractometer and the effects of microstresses in tensile strength of fibre measured by Instron have also been reported. The shift of 0.45 cm-1 in the Raman peak position of 1614.65 cm-1 to a higher value confirmed the development of microstresses due to neutron irradiation using micro-Raman technique. The defects due to irradiation were observed by SEM micrographs of single fibre for virgin and all irradiated samples.

  18. International Fusion Material Irradiation Facility (IFMIF) neutron source term simulation and neutronics analyses of the high flux test module

    CERN Document Server

    Simakov, S P; Heinzel, V; Moellendorff, U V

    2002-01-01

    The report describes the new results of the development work performed at Forschungszentrum Karlsruhe on the neutronics of the International Fusion Materials Irradiation Facility (IFMIF). An important step forward has been done in the simulation of neutron production of the deuteron-lithium source using the Li(d,xn) reaction cross sections from evaluated data files. The developed Monte Carlo routine and d-Li reaction data newly evaluated at INPE Obninsk have been verified against available experimental data on the differential neutron yield from deuteron-bombarded thick lithium targets. With the modified neutron source three-dimensional distributions of neutron and photon fluxes, displacement and gas production rates and nuclear heating inside the high flux test module (HFTM) were calculated. In order to estimate the uncertainty resulting from the evaluated data, two independent libraries, recently released by INPE and LANL, have been used in the transport calculations. The proposal to use a reflector around ...

  19. Influence of composition, heat treatment and neutron irradiation on the electrical conductivity of copper alloys

    DEFF Research Database (Denmark)

    Eldrup, Morten Mostgaard; Singh, B.N.

    1998-01-01

    The electrical conductivity of three different types of copper alloys, viz. CuNiBe, CuCrZr and Cu-Al(2)O(3) as well as of pure copper are reported. The alloys have undergone different pre-irradiation heat treatments and have been fission-neutron irradiated up to 0.3 dpa. In some cases post...

  20. On grain size dependent void swelling in pure copper irradiated with fission neutrons

    DEFF Research Database (Denmark)

    Singh, B.N.; Eldrup, Morten Mostgaard; Zinkle, S.J.

    2001-01-01

    in pure copper irradiated with fission neutrons at 623K to a dose level of approx0.3 dpa (displacement peratom). The post-irradiation defect microstructure including voids was investigated using transmission electron microscopy and positron annihilation spectroscopy. The evolution of void swelling...

  1. On grain-size-dependent void swelling in pure copper irradiated with fission neutrons

    DEFF Research Database (Denmark)

    Singh, Bachu Narain; Eldrup, Morten Mostgaard; Zinkle, S.J.

    2002-01-01

    in pure copper irradiated with fission neutrons at 623 K to a dose level of about 0.3 displacement per atom. The post-irradiation defect microstructure including voids was investigated using transmission electron microscopy and positron annihilation spectroscopy. The evolution of void swelling...

  2. The optimization study of Bonner sphere in the epi-thermal neutron irradiation field for BNCT.

    Science.gov (United States)

    Ueda, H; Tanaka, H; Maruhashi, A; Ono, K; Sakurai, Y

    2011-12-01

    The optimization study on the Bonner sphere in the epi-thermal neutron irradiation field for BNCT was done for the moderator material, moderator size, and activation foils as a neutron detector in the sphere. The saturated activity for the activation foil was obtained from the calculated response, and the effective energy range for each Bonner sphere was determined from the saturated activity. We can see that boric acid solution moderator is suitable for the spectrum measurement of a epi-thermal neutron irradiation field.

  3. Annihilation behavior of irradiation defects in Li4SiO4 irradiated with high thermal neutron fluence

    Science.gov (United States)

    Ran, Guangming; Xiao, Chengjian; Chen, Xiaojun; Gong, Yu; Zhao, Linjie; Wang, Heyi; Wang, Xiaolin

    2017-08-01

    The annihilation behavior of irradiation defects in Li4SiO4 which were irradiated with thermal neutrons to a high fluence was studied by electron spin resonance (ESR). It was observed that the ratio of O-related centers to E'-centers increased with increasing annealing temperature. The total irradiation defects were annihilated through two processes, namely the fast (120-250 °C, 70%) and the slow ones (250-500 °C, 30%), and their activation energies were determined to be 0.63 ± 0.09 and 0.89 ± 0.14 eV, respectively. The observed annihilation behavior of irradiation defects in Li4SiO4 was found to be very different from that in a previous study, which could be attributed to the difference in concentration and types of irradiation defects generated by different neutron fluences. It was implied that the annihilation behavior of irradiation defects in ternary lithium oxides would become more complicated with increasing neutron fluence.

  4. Analysis of neutron diffraction spectra acquired in situ during mechanical loading of shape memory NiTiFe at low temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Krishnan, V.B.; Manjeri, R.M. [Advanced Materials Processing and Analysis Center (AMPAC), Department of Mechanical, Materials and Aerospace Engineering, University of Central Florida, Orlando, FL 32816 (United States); Clausen, B.; Brown, D.W. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Vaidyanathan, R. [Advanced Materials Processing and Analysis Center (AMPAC), Department of Mechanical, Materials and Aerospace Engineering, University of Central Florida, Orlando, FL 32816 (United States)], E-mail: raj@mail.ucf.edu

    2008-05-25

    The Spectrometer for Materials Research at Temperature and Stress (SMARTS) at Los Alamos National Laboratory was used to acquire neutron diffraction spectra in situ during mechanical loading at 216 and 237 K. The experiments were performed with the objective of following the texture, strain and phase fraction evolution in the trigonal R-phase in a Ni{sub 46.8}Ti{sub 50}Fe{sub 3.2} shape memory alloy. A methodology to quantify the textures, strains and phase fractions using the General Structure Analysis System (GSAS) for Rietveld refinement of neutron diffraction spectra, is implemented and described. Emphasis is placed on evaluating the choice of P3 and P3-bar space groups for the R-phase in the refinements and the impact of this choice on the quantitative analyses of spectra.

  5. The low-temperature inflection observed in neutron scattering measurements of proteins is due to methyl rotation: direct evidence using isotope labeling and molecular dynamics simulations.

    Science.gov (United States)

    Wood, Kathleen; Tobias, Douglas J; Kessler, Brigitte; Gabel, Frank; Oesterhelt, Dieter; Mulder, Frans A A; Zaccai, Giuseppe; Weik, Martin

    2010-04-14

    There is increasing interest in the contribution of methyl groups to the overall dynamics measured by neutron scattering experiments of proteins. In particular an inflection observed in atomic mean square displacements measured as a function of temperature on high resolution spectrometers (approximately 1 microeV) was explained by the onset of methyl group rotations. By specifically labeling a non-methyl-containing side-chain in a native protein system, the purple membrane, and performing neutron scattering measurements, we here provide direct experimental evidence that the observed inflection is indeed due to methyl group rotations. Molecular dynamics simulations reproduce the experimental data, and their analysis suggests that the apparent transition is due to methyl group rotation entering the finite instrumental resolution of the spectrometer. Methyl group correlation times measured by solid state NMR in the purple membrane, taken from previous work, support the interpretation.

  6. Novel Pr-Cu magnetic phase at low temperature in PrBa2Cu3O6+x observed by neutron diffraction

    DEFF Research Database (Denmark)

    Boothroyd, A.T.; Longmore, A.; Andersen, N.H.

    1997-01-01

    We have studied by neutron diffraction the magnetic ordering in Al-free crystals of PrBa2Cu3O6+x (x = 0.35 and 0.92) that do not display the AFII Cu magnetic phase. Wt find that the Pr ordering below 20 K is accompanied by a counterrotation of the Cu antiferromagnetism on each plane of the bilaye...

  7. Microstructural evolution of pure tungsten neutron irradiated with a mixed energy spectrum

    Science.gov (United States)

    Koyanagi, Takaaki; Kumar, N. A. P. Kiran; Hwang, Taehyun; Garrison, Lauren M.; Hu, Xunxiang; Snead, Lance L.; Katoh, Yutai

    2017-07-01

    Microstructures of single-crystal bulk tungsten (W) and polycrystalline W foil with a strong grain texture were investigated using transmission electron microscopy following neutron irradiation at ∼90-800 °C to 0.03-4.6 displacements per atom (dpa) in the High Flux Isotope Reactor with a mixed energy spectrum. The dominant irradiation defects were dislocation loops and small clusters at ∼90 °C. Additional voids were formed in W irradiated at above 460 °C. Voids and precipitates involving transmutation rhenium and osmium were the dominant defects at more than ∼1 dpa. We found a new phenomenon of microstructural evolution in irradiated polycrystalline W: Re- and Os-rich precipitation along grain boundaries. Comparison of results between this study and previous studies using different irradiation facilities revealed that the microstructural evolution of pure W is highly dependent on the neutron energy spectrum in addition to the irradiation temperature and dose.

  8. Evaluation of gamma and neutron irradiation effects on the properties of mica film capacitors

    Indian Academy of Sciences (India)

    Rajesh Roy; Arun Pandya

    2005-12-01

    We present an investigation of gamma and neutron radiation effects on mica film capacitors from an electrical point of view. We have studied quantitatively the effects of gamma and neutron irradiation on mica film capacitors of thickness, 20 and 40 m (0.7874 and 1.5748 mil) with two different areas, 01 and 04 cm2. The capacitance has been measured at room temperature in the frequency range 100 Hz–10 MHz. Negligible change in the capacitance due to high gamma dose of 60Co, 15 kGy at dose rate 0.25 kGy/h, has been observed. However, appreciable change in the capacitance has been observed due to low doses of fast neutrons (cumulative dose, 115 cGy) with flux ∼ 9.925 × 107 neutrons/cm2 h from 252Cf neutron source of fluence, 2.5 × 107 neutrons/s. We have also observed that the impact of gamma and neutron irradiation is more at frequencies higher than 10 kHz. These results show that the mica capacitors do not show any radiation response below 10 kHz. The study shows the radiation response of mica film capacitors to gamma and fast neutron radiations. Mica capacitors show low gamma radiation response in comparison to fast neutron radiation, because a total dose of kGy order has been given by gamma source and only few cGy dose has been given by fast neutron source.

  9. Effect of neutron irradiation on charge collection efficiency in 4H-SiC Schottky diode

    Science.gov (United States)

    Wu, Jian; Jiang, Yong; Lei, Jiarong; Fan, Xiaoqiang; Chen, Yu; Li, Meng; Zou, Dehui; Liu, Bo

    2014-01-01

    The charge collection efficiency (CCE) in 4H-SiC Schottky diode is studied as a function of neutron fluence. The 4H-SiC diode was irradiated with fast neutrons of a critical assembly in Nuclear Physics and Chemistry Institute and CCE for 3.5 MeV alpha particles was then measured as a function of the applied reverse bias. It was found from our experiment that an increase of neutron fluence led to a decrease of CCE. In particular, CCE of the diode was less than 1.3% at zero bias after an irradiation at 8.26×1014 n/cm2. A generalized Hecht's equation was employed to analyze CCE in neutron irradiated 4H-SiC diode. The calculations nicely fit the CCE of 4H-SiC diode irradiated at different neutron fluences. According to the calculated results, the extracted electron μτ product (μτ)e and hole μτ product (μτ)h of the irradiated 4H-SiC diode are found to decrease by increasing the neutron fluence.

  10. Effects of neutron irradiation on the microstructure of alpha-annealed zircaloy-4

    Energy Technology Data Exchange (ETDEWEB)

    Bajaj, R.; Kammenzind, B.F. [Bettis Atomic Power Lab., West Mifflin, PA (United States); Farkas, D.M. [General Electric Co., Pleasanton, CA (United States). Vallecitos Nuclear Center

    2002-07-01

    Analytical electron microscopy (AEM) was used to study the separate effects of the irradiation parameters on the evolution of the microstructure in recrystallized alpha-annealed Zircaloy-4 under controlled irradiation conditions. The effects of fast neutron flux from {approx} 4 x 10{sup 13} n/cm{sup 2}-s to {approx} 1.5 x 10{sup 14} n/cm{sup 2}-s (E > 1 MeV){sup 3} neutron fluence in the range of {approx} 15 x 10{sup 20} n/cm{sup 2} to {approx} 50 x 10{sup 20} n/cm{sup 2} and temperature from {approx} 270 to {approx} 330 deg C were studied. The completeness of the test matrix and the exposure in the controlled environment of the advanced test reactor permitted the separate effects of fast neutron flux, fluence, and irradiation temperature to be delineated for the first time. It was found that an increase in the neutron flux increases the degree of amorphization of the second-phase precipitates but retards the redistribution of iron out of the amorphous region (neutron fluence and irradiation temperature remaining the same), whereas increasing temperature (neutron flux and neutron fluence remaining the same) has a reverse effect. Overall, the rate of amorphization of the second-phase precipitates observed in this work was larger than that predicted by many existing literature models. Finally, neither segregation of alloying elements to grain boundaries nor precipitation of any new phases were encountered. (authors)

  11. Evaluation of the neutron activation of JET in-vessel components following DT irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Vuolo, M.; Bonifetto, R.; Dulla, S. [Dipartimento Energia, Politecnico di Torino, I-10129 Torino (Italy); Heinola, K. [EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Association EURATOM-TEKES, University of Helsinki, PO Box 64, 00560 Helsinki (Finland); Lengar, I. [Association EURATOM-MESCS, Reactor Physics Division, Jožef Stefan Institute, Ljubljana (Slovenia); Ravetto, P., E-mail: piero.ravetto@polito.it [Dipartimento Energia, Politecnico di Torino, I-10129 Torino (Italy); Richard, L.Savoldi [Dipartimento Energia, Politecnico di Torino, I-10129 Torino (Italy); Villari, R. [Associazione EURATOM-ENEA sulla Fusione, Via Enrico Fermi 45, 00044 Frascati, Rome (Italy); Widdowson, A. [EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Zanino, R. [Dipartimento Energia, Politecnico di Torino, I-10129 Torino (Italy)

    2014-10-15

    Highlights: The temporal evolution of the radioactive species in the in-vessel components after the end of the JET-DT campaign is calculated; Different levels of neutron irradiation are assumed; The neutron flux in the selected components is calculated by the MCNP5 code; The neutron spectra are input to the FISPACT code that computes the evolution of the radioactive species; For each irradiation scenario, the time behavior of the contact dose rate is determined. Abstract: The forthcoming deuterium–tritium (DT) campaign at the Joint European Torus (JET) will induce a significant activation of the system components. In the present work we evaluate the temporal evolution of the radioactive species in the main in-vessel components after the end of the future DT campaign, assuming different levels of neutron irradiation. The neutron flux in the selected components is calculated by the MCNP5 code using the emission source by a typical DT plasma. The resulting neutron spectra are then input to the FISPACT code that computes the evolution of the radioactive species generated by the neutron activation process. For each irradiation scenario, the time behavior of the contact dose rate is determined.

  12. Neutron Flux Measurement at TAPIRO Fast Reactor for APD's Irradiation Fluence Evaluation

    CERN Document Server

    Angelone, M; Diemoz, Marcella; Festinesi, Armando; Longo, Egidio; Organtini, Giovanni; Rosi, G

    1998-01-01

    The Avalanche Photodiodes ( APD) were chosen as photon sensors for the region of the CMS electromagnetic calorimeter. The LHC will be a hard environment for what concerns the radiation levels in the detectors. The most relevant damage on APDs is caused by neutrons that produce an increase in the dark current of these devices. In the CMS-ECAL collaboration a big effort was indeed done to understand this damage, but the evaluation of the absolute effect was limited by the knowledge of the neutron flux calibration of the various irradiation facilities. This investigation describes the calibration of the neutron flux of the Tapiro reactor in Rome and the calculation of the Non-Ionizing-Energy-Loss on Silicon for this reactor. The damage parameter alpha for the APDs is evaluated to be about 10-11*10^-17 A/cm/neutron at 18C and 2 days after the irradiation. Some cross-checks with other irradiation facilities are also presented.

  13. Positron annihilation study of defects in GaAs irradiated by fission neutron

    Institute of Scientific and Technical Information of China (English)

    ZhuSheng-Yun; QianJia-Yu; 等

    1997-01-01

    The defects in Si-doped,N-type HB GaAs single crystal irradiated by En≥1 MeV fission neutrons(6.5×1015cm-2 and 1.4×1014cm-2)have been investigated using positron annihilation lifetime technique.The mono-and di-vacancies were created by irradiation and the tri-vacancies were formed during annealing.The concentration of defects is proportional to the irradiating neutron fluence.Three annealing stages were obsered at 250,450 and 650℃ for the mono-,di-and tri-vacancies,respectively.

  14. Spectrum evaluation at the filter-modified neutron irradiation field for neutron capture therapy in Kyoto University Research Reactor

    Science.gov (United States)

    Sakurai, Yoshinori; Kobayashi, Tooru

    2004-10-01

    The Heavy Water Neutron Irradiation Facility of the Kyoto University Research Reactor (KUR-HWNIF) was updated in March 1996, mainly to improve the facility for neutron capture therapy (NCT). In this facility, neutron beams with various energy spectra, from almost pure thermal to epithermal, are available. The evaluation of the neutron energy spectra by multi-activation-foil method was performed as a series of the facility characterization. The spectra at the normal irradiation position were evaluated for the combinations of heavy-water thickness of the spectrum shifter and the open-close condition of the cadmium and boral filters. The initial spectra were made mainly using a two-dimensional transport code, and the final spectra were obtained using an adjusting code. For the verification of the evaluated spectra, simulation calculations using a phantom were performed on the assumption of NCT-clinical-irradiation conditions. It resulted that the calculated data for the depth neutron-flux distributions were in good agreement with the experimental ones.

  15. Irradiation creep of nano-powder sintered silicon carbide at low neutron fluences

    Energy Technology Data Exchange (ETDEWEB)

    Koyanagi, Takaaki [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Shimoda, Kazuya [Kyoto Univ., Kyoto (Japan); Kondo, Sosuke [Kyoto Univ., Kyoto (Japan); Hinoki, Tatsuya [Kyoto Univ., Kyoto (Japan); Ozawa, Kazumi [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Katoh, Yutai [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)

    2014-12-01

    The irradiation creep behavior of nano-powder sintered silicon carbide was investigated using the bend stress relaxation method under neutron irradiation up to 1.9 dpa. The creep deformation was observed at all temperatures ranging from 380 to 1180 °C mainly from the irradiation creep but with the increasing contributions from the thermal creep at higher temperatures. Microstructural observation and data analysis were performed.

  16. Flux dependence of cluster formation in neutron-irradiated weld material

    Science.gov (United States)

    Bergner, F.; Ulbricht, A.; Hein, H.; Kammel, M.

    2008-03-01

    The effect of neutron flux on the formation of irradiation-induced clusters in reactor pressure vessel (RPV) steels is an unresolved issue. Small-angle neutron scattering was measured for a neutron-irradiated RPV weld material containing 0.22 wt% impurity Cu. The experiment was focused on the influence of neutron flux on the formation of irradiation-induced clusters at fixed fluence. The aim was to separate and tentatively interpret the effect of flux on the characteristics of the cluster size distribution. We have observed a pronounced effect of neutron flux on cluster size, whereas the total volume fraction of irradiation-induced clusters is insensitive to the level of flux. The result is compatible with a rate theory model according to which the range of applied fluxes covers the transition from a flux-independent regime at lower fluxes to a regime of decelerating cluster growth. The results are confronted with measured irradiation-induced changes of mechanical properties. Despite the observed flux effect on cluster size, both yield stress increase and transition temperature shift turned out to be independent of flux. This is in agreement with the volume fraction of irradiation-induced clusters being insensitive to the level of flux.

  17. Hydrogen absorption into neutron-irradiated graphite and estimation of the trapping effect

    Energy Technology Data Exchange (ETDEWEB)

    Atsumi, H [Department of Electric and Electronic Engineering, Kinki University, Kowakae 3-4-1, Higashi-Osaka 577-8502 (Japan); Shibata, N [Molecular and Material Engineering, Graduate School of Kinki University, Kowakae 3-4-1, Higashi-Osaka 577-8502 (Japan); Tanabe, T [Interdisciplinary Graduate School of Engineering Science, Kyushu University, Fukuoka 812-8581 (Japan); Shikama, T [Institute for Materials Research, Tohoku University, Sendai, 980-8577 (Japan)

    2007-03-15

    Bulk hydrogen retention and the analysis of absorption kinetics have been studied on graphite irradiated with neutrons at various conditions. Two kinds of hydrogen trapping sites may exist and be additionally produced during irradiation: interstitial cluster loop edge sites (trap 1) and carbon dangling bonds at edge surfaces of crystallites (trap 2). Neutron irradiation preferably creates trap 2 sites at lower fluences and trap 1 sites at a higher fluence. Trap 2 tends to be annealed out at high temperatures, although trap 1 is hardly decreased even at 1873 K. The activation energy of hydrogen diffusion is found to be increased from 1.04 to 1.60 eV by neutron irradiation.

  18. An investigation of neutron irradiation test on superplastic zirconia-ceramic materials

    Energy Technology Data Exchange (ETDEWEB)

    Shibata, Taiju; Ishihara, Masahiro; Baba, Shinichi; Hayashi, Kimio [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment; Motohashi, Yoshinobu [Ibaraki Univ., Mito (Japan)

    2000-05-01

    A neutron irradiation test on superplastic ceramic materials at high temperature has been proposed as an innovative basic research on high-temperature engineering using the High Temperature Engineering Test Reactor (HTTR). For the effective execution of the test, we reviewed the superplastic deformation mechanism of ceramic materials and discussed neutron irradiation effects on the superplastic deformation process of stabilized Tetragonal Zirconia Polycrystal (TZP), which is a representative superplastic ceramic material. As a result, we pointed out that the decrease in the activation energy for superplastic deformation is expected by the radiation-enhanced diffusion. We selected a fast neutron fluence of 5x10{sup 20} n/cm{sup 2} and an irradiation temperature of about 600degC as test conditions for the first irradiation test on TZP and decided to perform a preliminary irradiation test by the Japan Materials Testing Reactor (JMTR). Moreover, we estimated the radioactivity of irradiated TZP and indicated that it is in the order of 10{sup 10} Bq/g (about 0.3 Ci/g) immediately after irradiation to a thermal neutron fluence of 3x10{sup 20} n/cm{sup 2} and that it decays to about 1/100 in a year. (author)

  19. Irradiation of Polyimide and Neutron Poison Materials by Using a HANARO Capsule

    Energy Technology Data Exchange (ETDEWEB)

    Choo, K. N.; Cho, M. S.; Shin, Y. T.; Kim, B. G.; Seo, C. G.; Kim, Y. K. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2009-05-15

    A material capsule system has been developed for an irradiation test of non-fissile materials in HANARO (High flux Advanced Neutron Application ReactOr).This capsule system has been actively utilized for the various material irradiation tests requested by users from research institutes, universities, and the industries. The capsules were mainly designed for an irradiation of the RPV (Reactor Pressure Vessel) and reactor core materials, and Zr-based alloys of parts of nuclear fuel assembly. Recently, irradiation tests of neutron poison materials and Polyimide were requested by Westinghouse Electric Company (WEC) and Hanyang University, respectively. As a candidate material of control rod of AP1000 reactor, Ag and Ag-In-Cd alloys were requested to be irradiated in HANARO by WEC. Polyimide has been studied as a shielding material against thermal and fast neutrons. The irradiation of these new materials which might affect the safety of a reactor was carried out for the first time in HANARO. As a preliminary test, small amount of these materials were determined to be inserted in a KNF (Korea Nuclear Fuel) irradiation capsule of 07M-13N. Due to the new materials, the irradiation test of the 07M-13N capsule was examined and approved by the 'HANARO Safety Review Committee'. The 07M-13N capsule was safely irradiated for 95.19 days (4 cycles) in the CT test hole of HANARO of a 30MW thermal output at 230{approx}420 .deg. C. The specimens of these new materials were irradiated up to a maximum fast neutron fluence of 1.13x1021(n/cm{sup 2}) (E>1.0MeV) and the dpa of the irradiated specimens were evaluated as 1.87.

  20. Defects annihilation behavior of neutron-irradiated SiC ceramics densified by liquid-phase-assisted method after post-irradiation annealing

    National Research Council Canada - National Science Library

    Idris, Mohd Idzat; Yamazaki, Saishun; Yoshida, Katsumi; Yano, Toyohiko

    2016-01-01

    Numerous studies on the recovery behavior of neutron-irradiated high-purity SiC have shown that most of the defects present in it are annihilated by post-irradiation annealing, if the neutron fluence is less than 1×1026 n/m2 (>0.1MeV...

  1. Emesis ED50 of Neutron Irradiation and Prophylactic Effectiveness.

    Science.gov (United States)

    1985-08-01

    Gamma rays were aximized by thermalizing neutrons in 30.5 cm (12 in.) of water, then absorbing the thermal eutrons in a gadolinium-cadmium shield. The...12 in.) from the tank protrusion in exposure room 1. The neu- tron component was minimized by thermalization of the neutrons by the 30.5 cm (12 in...of water between the core and the exposure room. The thermalized neutrons were subsequently captured in the gadolinium-cadmium on the tank wall. The

  2. Controllability of depth dose distribution for neutron capture therapy at the Heavy Water Neutron Irradiation Facility of Kyoto University Research Reactor.

    Science.gov (United States)

    Sakurai, Yoshinori; Kobayashi, Tooru

    2002-10-01

    The updating construction of the Heavy Water Neutron Irradiation Facility of the Kyoto University Research Reactor has been performed from November 1995 to March 1996 mainly for the improvement in neutron capture therapy. On the performance, the neutron irradiation modes with the variable energy spectra from almost pure thermal to epi-thermal neutrons became available by the control of the heavy-water thickness in the spectrum shifter and by the open-and-close of the cadmium and boral thermal neutron filters. The depth distributions of thermal, epi-thermal and fast neutron fluxes were measured by activation method using gold and indium, and the depth distributions of gamma-ray absorbed dose rate were measured using thermo-luminescent dosimeter of beryllium oxide for the several irradiation modes. From these measured data, the controllability of the depth dose distribution using the spectrum shifter and the thermal neutron filters was confirmed.

  3. Biological effectiveness of neutron irradiation on animals and man

    Energy Technology Data Exchange (ETDEWEB)

    Straume, T.

    1982-11-01

    Neutron experiments on a highly radiosensitive in vivo system - oocytes in mice - provide new insight into the nature of the radiosensitive targets of these important cells. With the radiobiological literature as background, neutron data from animals and humans are integrated, and the controversial question of radiation protection standards for neutrons is addressed. Oocyte killing in juvenile mice by 0.43-MeV, /sup 252/Cf-fission, and 15 MeV neutrons, compared with that by /sup 60/Co gamma rays, yields unusually low neutron RBEs (relative biological effectiveness). At 0.1 rad of 0.43-MeV neutrons the RBE is only 1.8, contrasting greatly with values of 100 or more reported at low-doses for other endpoints. In mice just prior to birth, however, when oocytes are less radiosensitive, the neutron RBE is much higher, similar to values for most other mammalian endpoints. This dramatic change in neutron RBE with mouse age (occurring within 2 to 3 days) can be explained as the result of a shift from a less radiosensitive target (presumably nuclear DNA) to a much more radiosensitive one (probably the oocyte plasma membrane). Using various approaches, a value for the neutron Quality Factor (Q, a radiation protection standard) is estimated as 17 (+-100%), much lower than 100 which has been suggested. With the large uncertainty, 17 is not markedly different from the value of 10 presently in general use.

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

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Tae-Hyun; Park, Jiho; Kim, Jun Yeon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, HyungTae; Park, Kyoungsoo [Yonsei University, Seoul (Korea, Republic of); Kim, Sang-Ho [Hyundai Engineering, Seoul (Korea, Republic of)

    2015-10-15

    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{sup 19} n/cm{sup 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.

  5. Investigation of reactor neutron irradiation induced dark signals increase in COTS array CCDs

    Directory of Open Access Journals (Sweden)

    Zujun Wang

    2014-09-01

    Full Text Available The experiments of reactor neutron irradiation which induce dark signal increase in COTS array CCDs are presented. The flux of the reactor neutron beams was about 1.33 × 108 n/cm2s. The three samples were exposed to 1MeV neutron-equivalent fluences of 1 × 1011, 5 × 1011, and 1 × 1012 n/cm2, respectively. The mean dark signal (KD, dark signal non-uniformity (DSNU, and dark signal spikes (hot pixels versus neutron fluence are investigated. The degradation mechanisms of the dark signal in CCDs are analyzed. The mean dark signal increase due to neutron displacement damage appears to be proportional to displacement damage dose. The dark images from the CCDs irradiated by neutrons are presented to investigate the generation of dark signal spike. The 1D and 2D figures which show the output signal voltage of pixels in dark images irradiated by different neutron beam fluences, are presented to compare the degradation of KD, DSNU, and dark signal spike.

  6. Design of sample carrier for neutron irradiation facility at TRIGA MARK II nuclear reactor

    Science.gov (United States)

    Abdullah, Y.; Hamid, N. A.; Mansor, M. A.; Ahmad, M. H. A. R. M.; Yusof, M. R.; Yazid, H.; Mohamed, A. A.

    2013-06-01

    The objective of this work is to design a sample carrier for neutron irradiation experiment at beam ports of research nuclear reactor, the Reaktor TRIGA PUSPATI (RTP). The sample carrier was designed so that irradiation experiment can be performed safely by researchers. This development will resolve the transferring of sample issues faced by the researchers at the facility when performing neutron irradiation studies. The function of sample carrier is to ensure the sample for the irradiation process can be transferred into and out from the beam port of the reactor safely and effectively. The design model used was House of Quality Method (HOQ) which is usually used for developing specifications for product and develop numerical target to work towards and determining how well we can meet up to the needs. The chosen sample carrier (product) consists of cylindrical casing shape with hydraulic cylinders transportation method. The sample placing can be done manually, locomotion was by wheel while shielding used was made of boron materials. The sample carrier design can shield thermal neutron during irradiation of sample so that only low fluencies fast neutron irradiates the sample.

  7. Neutron irradiation effects on gallium nitride-based Schottky diodes

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Chung-Han; Katz, Evan J.; Zhang, Zhichun [Department of Electrical and Computer Engineering, The Ohio State University, Columbus Ohio 43210 (United States); Qiu, Jie; Cao, Lei [Nuclear Engineering Program, Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, Ohio 43210 (United States); Mishra, Umesh K. [Departments of Electrical and Computer Engineering and Materials Science and Engineering, University of California, Santa Barbara, California 93106 (United States); Brillson, Leonard J. [Department of Electrical and Computer Engineering, The Ohio State University, Columbus Ohio 43210 (United States); Department of Physics and Center for Materials Research, The Ohio State University, Columbus, Ohio 43210 (United States)

    2013-10-14

    Depth-resolved cathodoluminescence spectroscopy (DRCLS), time-resolved surface photovoltage spectroscopy, X-ray photoemission spectroscopy (XPS), and current-voltage measurements together show that fast versus thermal neutrons differ strongly in their electronic and morphological effects on metal-GaN Schottky diodes. Fast and thermal neutrons introduce GaN displacement damage and native point defects, while thermal neutrons also drive metallurgical reactions at metal/GaN interfaces. Defect densities exhibit a threshold neutron fluence below which thermal neutrons preferentially heal versus create new native point defects. Scanning XPS and DRCLS reveal strong fluence- and metal-dependent electronic and chemical changes near the free surface and metal interfaces that impact diode properties.

  8. Neutron irradiation effects on metal-gallium nitride contacts

    Energy Technology Data Exchange (ETDEWEB)

    Katz, Evan J.; Lin, Chung-Han; Zhang, Zhichun [Department of Electrical and Computer Engineering, The Ohio State University, Columbus, Ohio 43210 (United States); Qiu, Jie; Cao, Lei [Nuclear Engineering Program, Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, Ohio 43210 (United States); Mishra, Umesh K. [Departments of Electrical and Computer Engineering and Materials Science and Engineering University of California, Santa Barbara, California 93106 (United States); Brillson, Leonard J., E-mail: brillson.1@osu.edu [Department of Electrical and Computer Engineering, The Ohio State University, Columbus, Ohio 43210 (United States); Department of Physics and Center for Materials Research, The Ohio State University, Columbus, Ohio 43210 (United States)

    2014-03-28

    We have measured the effect of fast and thermal neutrons on GaN Schottky barriers and ohmic contacts using current–voltage and transmission line method electrical techniques, optical, atomic force and scanning electron microscopy morphological techniques, and X-ray photoemission spectroscopy chemical techniques. These studies reveal a 10{sup 15} n/cm{sup 2} neutron threshold for Schottky barrier ideality factor increases, a 10{sup 15} n/cm{sup 2} fast plus thermal neutron threshold for ohmic contact sheet and contact resistance increases, and 10{sup 16} n/cm{sup 2} neutron fluence threshold for major device degradation identified with thermally driven diffusion of Ga and N into the metal contacts and surface phase changes. These results demonstrate the need for protecting metal-GaN contacts in device applications subject to neutron radiation.

  9. Effects of helium content of microstructural development in Type 316 stainless steel under neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Maziasz, P.J.

    1985-11-01

    This work investigated the sensitivity of microstructural evolution, particularly precipitate development, to increased helium content during thermal aging and during neutron irradiation. Helium (110 at. ppM) was cold preinjected into solution annealed (SA) DO-heat type 316 stainess steel (316) via cyclotron irradiation. These specimens were then exposed side by side with uninjected samples. Continuous helium generation was increased considerably relative to EBR-II irradiation by irradiation in HFIR. Data were obtained from quantitative analytical electron microscopy (AEM) in thin foils and on extraction replicas. 480 refs., 86 figs., 19 tabs.

  10. Search for the First-Order Liquid-to-Liquid Phase Transition in Low-Temperature Confined Water by Neutron Scattering

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Sow-Hsin [Massachusetts Institute of Technology (MIT); Wang, Zhe [Massachusetts Institute of Technology (MIT); Kolesnikov, Alexander I [ORNL; Zhang, Yang [ORNL; Liu, Kao-Hsiang [National Taiwan University

    2013-01-01

    It has been conjectured that a 1st order liquid-to-liquid (L-L) phase transition (LLPT) between high density liquid (HDL) and low density liquid (LDL) in supercooled water may exist, as a thermodynamic extension to the liquid phase of the 1st order transition established between the two bulk solid phases of amorphous ice, the high density amorphous ice (HDA) and the low density amorphous ice (LDA). In this paper, we first recall our previous attempts to establish the existence of the 1st order L-L phase transition through the use of two neutron scattering techniques: a constant Q elastic diffraction study of isobaric temperature scan of the D2O density, namely, the equation of state (EOS) measurements. A pronounced density hysteresis phenomenon in the temperature scan of the density above P = 1500 bar is observed which gives a plausible evidence of crossing the 1st order L-L phase transition line above this pressure; an incoherent quasi-elastic scattering measurements of temperature-dependence of the alpha-relaxation time of H2O at a series of pressures, namely, the study of the Fragile-to-Strong dynamic crossover (FSC) phenomenon as a function of pressure which we interpreted as the results of crossing the Widom line in the one-phase region. In this new experiment, we used incoherent inelastic neutron scattering (INS) to measure the density of states (DOS) of H atoms in H2O molecules in confined water as function of temperature and pressure, through which we may be able to follow the emergence of the LDL and HDL phases at supercooled temperature and high pressures. We here report for the first time the differences of librational and translational DOSs between the hypothetical HDL and LDL phases, which are similar to the corresponding differences between the well-established HDA and LDA ices. This is plausible evidence that the HDL and LDL phases are the thermodynamic extensions of the corresponding amorphous solid water HDA and LDA ices.

  11. The effects of gamma irradiation on neutron displacement sensitivity of lateral PNP bipolar transistors

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Chenhui, E-mail: wangchenhui@nint.ac.cn; Chen, Wei; Liu, Yan; Jin, Xiaoming; Yang, Shanchao; Qi, Chao

    2016-09-21

    The effects of gamma irradiation on neutron displacement sensitivity of four types of lateral PNP bipolar transistors (LPNPs) with different neutral base widths, emitter widths and the doping concentrations of the epitaxial base region are studied. The physical mechanisms of the effects are explored by defect analysis using deep level transient spectroscopy (DLTS) techniques and numerical simulations of recombination process in the base region of the lateral PNP bipolar transistors, and are verified by the experiments on gate-controlled lateral PNP bipolar transistors (GCLPNPs) manufactured in the identical commercial bipolar process with different gate bias voltage. The results indicate that gamma irradiation increases neutron displacement damage sensitivity of lateral PNP bipolar transistors and the mechanism of this phenomenon is that positive charge induced by gamma irradiation enhances the recombination process in the defects induced by neutrons in the base region, leading to larger recombination component of base current and greater gain degradation.

  12. Influence of Fast Neutron Irradiation on Critical Current Densities of Bi-2223/Ag Tape

    Institute of Scientific and Technical Information of China (English)

    Duan Zhenzhong

    2004-01-01

    Experimental results on the magnetic field behavior of the critical current in silver sheathed Bi-2223 tapes are presented. The experiments consist of transport and magnetic measurements in a wide temperature range and in external magnetic field up to 6 T. Significant enhancement of the intragrain critical current densities Jc are observed after irradiation with fast neutron. This is attributed to an improvement of flux pinning capability by the neutron induced defects, but the weak link structure is somewhat damaged as evidenced by the small degradation of transport critical current at low field. According to the measurement of remanent magnetic moment before and after irradiation with fast neutron, the connectivity in Bi-2223 tapes is reduced by 50% after irradiated to a fluence of 2 × 1021 m-2, which resulted in the critical currents degradated by a factor of 10%.

  13. Correlation between locally deformed structure and oxide film properties in austenitic stainless steel irradiated with neutrons

    Science.gov (United States)

    Chimi, Yasuhiro; Kitsunai, Yuji; Kasahara, Shigeki; Chatani, Kazuhiro; Koshiishi, Masato; Nishiyama, Yutaka

    2016-07-01

    To elucidate the mechanism of irradiation-assisted stress corrosion cracking (IASCC) in high-temperature water for neutron-irradiated austenitic stainless steels (SSs), the locally deformed structures, the oxide films formed on the deformed areas, and their correlation were investigated. Tensile specimens made of irradiated 316L SSs were strained 0.1%-2% at room temperature or at 563 K, and the surface structures and crystal misorientation among grains were evaluated. The strained specimens were immersed in high-temperature water, and the microstructures of the oxide films on the locally deformed areas were observed. The appearance of visible step structures on the specimens' surface depended on the neutron dose and the applied strain. The surface oxides were observed to be prone to increase in thickness around grain boundaries (GBs) with increasing neutron dose and increasing local strain at the GBs. No penetrative oxidation was observed along GBs or along surface steps.

  14. Nuclear data needs for neutron spectrum tailoring at International Fusion Materials Irradiation Facility (IFMIF)

    Energy Technology Data Exchange (ETDEWEB)

    Sugimoto, Masayoshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2001-03-01

    International Fusion Materials Irradiation Facility (IFMIF) is a proposal of D-Li intense neutron source to cover all aspects of the fusion materials development in the framework of IEA collaboration. The new activity has been started to qualifying the important technical issues called Key Element technology Phase since 2000. Although the neutron spectrum can be adjusted by changing the incident beam energy, it is favorable to be carried out many irradiation tasks at the same time under the unique beam condition. For designing the tailored neutron spectrum, neutron nuclear data for the moderator-reflector materials up to 50 MeV are required. The data for estimating the induced radioactivity is also required to keep the radiation level low enough at maintenance time. The candidate materials and the required accuracy of nuclear data are summarized. (author)

  15. Neutron flux optimization in irradiation facilities at Peruvian research reactor RP-10

    Energy Technology Data Exchange (ETDEWEB)

    Vela, M.; Arrieta, R.; Salazar, A.; Urcia, A.; Canaza, D.; Felix, J; Veramendi, E.; Ovalle, E.; Giol, R.; Zapata, L.; Ramos, F.; Tordocillo, J. [Instituto Peruano de Energia Nuclear (IPEN), Lima (Peru). Direccion de Instalaciones. Dept. de Reactores]. E-mail: mvela@ipen.gob.pe; rarrieta@ipen.gob.pe

    2005-07-01

    In this work we show the values distribution of the neutron flux at Peruvian Research Reactor RP-10, determined under two different safety and control rods configurations. The method applied was to irradiate small gold foils in irradiation facilities of the core to carry out the nuclear reaction {sup 197}Au(n, {gamma}){sup 198}Au; then using a gamma spectrometry system and the Westcott formalism we obtained the neutron flux. The results confirm the favorable effect of such configurations, increasing the neutron flux, both thermal and epithermal. These results have consistency with the weekly activity reports of radioisotopes lots given by the Radioisotopes Production Plant and Neutron Activation Analysis Group. (author)

  16. Quantitative TEM analysis of precipitation and grain boundary segregation in neutron irradiated EUROFER 97

    Energy Technology Data Exchange (ETDEWEB)

    Dethloff, Christian, E-mail: christian.dethloff@kit.edu; Gaganidze, Ermile; Aktaa, Jarir

    2014-11-15

    Characterization of irradiation induced microstructural defects is essential for assessing the applicability of structural steels like the Reduced Activation Ferritic/Martensitic steel EUROFER 97 in upcoming fusion reactors. In this work Transmission Electron Microscopy (TEM) is used to analyze the types and structure of precipitates, and the evolution of their size distributions and densities caused by neutron irradiation to a dose of 32 displacements per atom (dpa) at 330–340 °C in the irradiation experiment ARBOR 1. A significant growth of MX and M{sub 23}C{sub 6} type precipitates is observed after neutron irradiation, while the precipitate density remains unchanged. Hardening caused by MX and M{sub 23}C{sub 6} precipitate growth is assessed by applying the Dispersed Barrier Hardening (DBH) model, and shown to be of minor importance when compared to other irradiation effects like dislocation loop formation. Additionally, grain boundary segregation of chromium induced by neutron irradiation was investigated and detected in irradiated specimens.

  17. Neutron dosimetry and damage calculations for the ATR-A1 irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Greenwood, L.R.; Ratner, R.T. [Pacific Northwest National Lab., Richland, WA (United States)

    1998-09-01

    Neutron fluence measurements and radiation damage calculations are reported for the collaborative US/Japan ATR-A1 irradiation in the Advanced Test Reactor (ATR) at Idaho National Engineering Laboratory (INEL). The maximum total neutron fluence at midplane was 9.4 {times} 10{sup 21} n/cm{sup 2} (5.5 {times} 10{sup 21} n/cm{sup 2} above 0.1 MeV), resulting in about 4.6 dpa in vanadium.

  18. Fabrication of solution-processed amorphous indium zinc oxide thin-film transistors at low temperatures using deep-UV irradiation under wet conditions

    Science.gov (United States)

    Park, Jee Ho; Chae, Soo Sang; Yoo, Young Bum; Lee, Ji Hoon; Lee, Tae Il; Baik, Hong Koo

    2014-03-01

    We fabricated solution-processed indium zinc oxide (IZO) thin film transistors (TFTs) at annealing temperatures as low as 250 °C using deep UV (DUV) irradiation in water vapor medium. The DUV light decomposed the carbon compounds in the IZO films, and the hydroxyl radicals generated when water vapor reacted with ozone effectively oxidized the films. These phenomena were confirmed by X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. Finally, we fabricated DUV-treated IZO TFTs in water-vapor medium at 250 °C with a mobility of 1.2 cm2/Vs and an on/off current ratio of 2.66 × 106.

  19. Interaction between solute atoms and radiation defects in Fe-Ni-Si and Fe-Mn-Si alloys under irradiation with proton ions at low-temperature

    Science.gov (United States)

    Murakami, Kenta; Iwai, Takeo; Abe, Hiroaki; Sekimura, Naoto

    2016-12-01

    Isochronal annealing followed by residual resistivity measurements at 12 K was performed in Fe-0.6Ni-0.6Si and Fe-1.5Mn-0.6Si alloys irradiated with 1 MeV proton ions below 70 K, and recovery stages were compared with those of Fe-0.6Ni and Fe-1.5Mn. The effects of silicon addition in the Fe-Ni alloy was observed as the appearance of a new recovery stage at 282-372 K, presumably corresponding to clustering of solute atoms in matrix, and as a change in mixed dumbbell migration at 122-142 K. Silicon addition mitigated the manganese effect in Fe-Mn alloy that is obstructing the recovery of radiation defects. Reduction of resistivity in Fe-Mn-Si alloy also suggested formation of small solute atom clusters.

  20. Tensile properties of vanadium-base alloys irradiated in the Fusion-1 low-temperature experiment in the BOR-60 reactor

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, H.; Gazda, J.; Nowicki, L.J.; Billone, M.C.; Smith, D.L. [Argonne National Lab., IL (United States)

    1998-09-01

    The irradiation has been completed and the test specimens have been retrieved from the lithium-bonded capsule at the Research Institute of Atomic Reactors (RIAR) in Russia. During this reporting period, the Argonne National Laboratory (ANL) tensile specimens were received from RIAR and initial testing and examination of these specimens at ANL has been completed. The results, corroborating previous findings showed a significant loss of work hardening capability in the materials. There appears to be no significant difference in behavior among the various heats of vanadium-base alloys in the V-(4-5)Cr-(4-5)Ti composition range. The variations in the preirradiation annealing conditions also produced no notable differences.

  1. Antiradiation Vaccine: Technology Development Of Prophylaxis, Prevention And Treatment Of Biological Consequences And Complications After Neutron Irradiation.

    Science.gov (United States)

    Popov, Dmitri; Maliev, Slava; Jones, Jeffrey

    Introduction: Neutrons irradiation produce a unique biological effectiveness compare to different types of radiation because their ability to create a denser trail of ionized atoms in biological living tissues[Straume 1982; Latif et al.2010; Katz 1978; Bogatyrev 1982]. The efficacy of an Anti-Radiation Vaccine for the prophylaxis, prevention and therapy of acute radiation pathology was studied in a neutron exposure facility. The biological effects of fast neutrons include damage of central nervous system and cardiovascular system with development of Acute Cerebrovascular and Cardiovascular forms of acute radiation pathology. After irradiation by high doses of fast neutron, formation of neurotoxins, hematotoxins,cytotoxins forming from cell's or tissue structures. High doses of Neutron Irradiation generate general and specific toxicity, inflammation reactions. Current Acute Medical Management and Methods of Radiation Protection are not effective against moderate and high doses of neutron irradiation. Our experiments demonstrate that Antiradiation Vaccine is the most effective radioprotectant against high doses of neutron-radiation. Radiation Toxins(biological substances with radio-mimetic properties) isolated from central lymph of gamma-irradiated animals could be working substance with specific antigenic properties for vaccination against neutron irradiation. Methods: Antiradiation Vaccine preparation standard - mixture of a toxoid form of Radiation Toxins - include Cerebrovascular RT Neurotoxin, Cardiovascular RT Neurotoxin, Gastrointestinal RT Neurotoxin, Hematopoietic RT Hematotoxin. Radiation Toxins were isolated from the central lymph of gamma-irradiated animals with different forms of Acute Radiation Syndromes - Cerebrovascular, Cardiovascular, Gastrointestinal, Hematopoietic forms. Devices for Y-radiation were "Panorama","Puma". Neutron exposure was accomplished at the Department of Research Institute of Nuclear Physics, Dubna, Russia. The neutrons

  2. Low-temperature crystallization of TiO{sub 2} nanotube arrays via hot water treatment and their photocatalytic properties under visible-light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Krengvirat, Warapong [School of Materials and Mineral Resources Engineering, Engineering Campus, Universiti Sains Malaysia, Penang 14300 (Malaysia); Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, Aichi 441-8580 (Japan); Sreekantan, Srimala, E-mail: warapong001@hotmail.com [School of Materials and Mineral Resources Engineering, Engineering Campus, Universiti Sains Malaysia, Penang 14300 (Malaysia); Mohd Noor, Ahmad-Fauzi [School of Materials and Mineral Resources Engineering, Engineering Campus, Universiti Sains Malaysia, Penang 14300 (Malaysia); Negishi, Nobuaki [Institute for Environmental Management Technology, National Institute of Advanced, Industrial Science and Technology, Tsukuba, Ibaraki 305-8569 (Japan); Kawamura, Go; Muto, Hiroyuki [Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, Aichi 441-8580 (Japan); Matsuda, Atsunori, E-mail: matsuda@ee.tut.ac.jp [Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, Aichi 441-8580 (Japan)

    2013-01-15

    This work demonstrates the facile method to crystallize TiO{sub 2} nanotube arrays by simple immersion of amorphous TiO{sub 2} nanotube arrays into hot water at {approx}70-90 Degree-Sign C under ambient pressure and neutral pH. Hot water treatment induced the transformation of smooth nanotubes walls to granular anatase TiO{sub 2} nanoparticles. Higher treatment temperature and longer exposure time promoted the growth of anatase TiO{sub 2} nanocrystallites, and also lowered number of oxygen vacancies (V{sub O}{sup Bullet Bullet }). Furthermore, it allowed the adsorption of hydroxyl (OH) species and H{sub 2}O as well as the generation of the surface state, ca., Ti{sup 3+}. The presence of interstitial carbon species and surface states enabled the visible-light absorption. The adsorbed OH species and H{sub 2}O stimulated the photocatalytic oxidation by instantaneous reaction at the surface of nanotubes. Anatase TiO{sub 2} nanocrystallites formed by hot water treatment at 90 Degree-Sign C for 3 h exhibited efficient photocatalytic removal of dyes under visible-light irradiation with the decomposition rate of {approx}11% h{sup -1}, which is relatively higher than that of heat-treated arrays ({approx}9% h{sup -1}). The results indicate the potential of hot water treatment for the formation of anatase TiO{sub 2} nanocrystallites with efficient photocatalytic properties. -- Highlights: Black-Right-Pointing-Pointer Visible-light responsive TiO{sub 2} nanotubes were crystallized by immersion into hot water. Black-Right-Pointing-Pointer Temperature and exposure time determined the crystal growth and surface defect. Black-Right-Pointing-Pointer The presence of surface-active site contributed to a higher photocatalytic activity. Black-Right-Pointing-Pointer The product exhibited remarkable photo-degradation under visible-light irradiation.

  3. Mechanical and microstructural properties of neutron irradiated Fe-Cr-C alloys

    Energy Technology Data Exchange (ETDEWEB)

    Konstantinovic, M.J.; Renterghem, W. van; Matijasevic, M.; Minov, B.; Lambrecht, M.; Chiapetto, M.; Malerba, L. [Studiecentrum voor Kernenergie/Centre d' Etude de l' Energie Nucleaire (SCK-CEN), Mol (Belgium); Toyama, T. [Institute for Materials Research, Tohoku University, Sendai (Japan)

    2016-11-15

    Defect properties of neutron irradiated Fe-Cr-C alloys and their influence on the mechanical behavior are studied by combining mechanical tests, microstructural examination, and the results of models. It is found that the initial microstructure of these alloys, determined by the Cr and C concentrations, as well as by the thermal treatment, can account for different defect formation and distribution after neutron irradiation. On the basis of these results, a correlation between defect properties and macroscopic mechanical behavior is proposed. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  4. Correlation between locally deformed structure and oxide film properties in austenitic stainless steel irradiated with neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Chimi, Yasuhiro, E-mail: chimi.yasuhiro@jaea.go.jp [Japan Atomic Energy Agency (JAEA), 2-4 Shirakata, Tokai-mura, Naka-gun, Ibaraki 319-1195 (Japan); Kitsunai, Yuji [Nippon Nuclear Fuel Development, 2163 Narita-cho, Oarai-machi, Higashi-ibaraki-gun, Ibaraki 311-1313 (Japan); Kasahara, Shigeki [Japan Atomic Energy Agency (JAEA), 2-4 Shirakata, Tokai-mura, Naka-gun, Ibaraki 319-1195 (Japan); Chatani, Kazuhiro; Koshiishi, Masato [Nippon Nuclear Fuel Development, 2163 Narita-cho, Oarai-machi, Higashi-ibaraki-gun, Ibaraki 311-1313 (Japan); Nishiyama, Yutaka [Japan Atomic Energy Agency (JAEA), 2-4 Shirakata, Tokai-mura, Naka-gun, Ibaraki 319-1195 (Japan)

    2016-07-15

    To elucidate the mechanism of irradiation-assisted stress corrosion cracking (IASCC) in high-temperature water for neutron-irradiated austenitic stainless steels (SSs), the locally deformed structures, the oxide films formed on the deformed areas, and their correlation were investigated. Tensile specimens made of irradiated 316L SSs were strained 0.1%–2% at room temperature or at 563 K, and the surface structures and crystal misorientation among grains were evaluated. The strained specimens were immersed in high-temperature water, and the microstructures of the oxide films on the locally deformed areas were observed. The appearance of visible step structures on the specimens' surface depended on the neutron dose and the applied strain. The surface oxides were observed to be prone to increase in thickness around grain boundaries (GBs) with increasing neutron dose and increasing local strain at the GBs. No penetrative oxidation was observed along GBs or along surface steps. - Highlights: • Visible step structures depend on the neutron dose and the applied strain. • Local strain at grain boundaries was accumulated with the neutron dose. • Oxide thickness increases with neutron dose and local strain at grain boundaries. • No penetrative oxidation was observed along grain boundaries or surface steps.

  5. Presence of interleukin 6 at the cutaneous level after in vivo neutron irradiation; Presence d`interleukine 6 au niveau cutane apres irradiation neutronique in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Agay, D.; Pradeau, P.; Edgard, L.; Van Uye, A.; Mestries, J.C.

    1994-12-31

    In this study we investigated the in situ localization of IL-6 in mixed neutron-gamma irradiated baboons belly skin. Using immunohistochemical methods, we demonstrated the presence of IL-6 as early as the first day after the irradiation day. However experimental conditions did not allow us to conclude to a causality relation between irradiation and IL-6 cutaneous presence. (author). 4 refs.

  6. Organic materials irradiated at very low temperature and at different stopping powers: examples of polyethylene and of cyclohexane molecules trapped in matrix; Materiaux organiques irradies a tres basse temperature et a differents pouvoirs d'arret: cas du polyethylene et des molecules de cyclohexane isolees en matrice

    Energy Technology Data Exchange (ETDEWEB)

    Melot, M

    2003-10-15

    This thesis concerns the formation mechanisms of defects created in organic materials during irradiation under vacuum, at very low temperature and at different electronic stopping powers. Analysis have been realised by infrared spectroscopy. The first part concerns polyethylene. Irradiating at 8 K allows to dissociate the direct irradiation effects (in cage reactions) and the radical recombination effects. According to the considered chemical groups, the radical mobility leads to very different changes for the formation radiochemical yields. The second part concerns the irradiation of cyclohexane molecules trapped in a solid argon matrix. We evaluate the contribution of intermolecular and intramolecular reactions. The intermolecular reactions have limited consequences when using low ionising radiations but are crucial for heavy ion irradiations. (author)

  7. Mechanical properties and microstructure of neutron irradiated cold worked Al-6063 alloy

    Energy Technology Data Exchange (ETDEWEB)

    Munitz, A.; Shtechman, A.; Cotler, C.; Dahan, S. [Nuclear Res. Center-Negev, Beer-Sheva (Israel); Talianker, M. [Ben-Gurion Univ., Beer-Sheva (Israel). Dept. of Materials Science

    1998-01-01

    The impact of neutron irradiation on the mechanical properties and fracture morphology of cold worked Al-6063 were studied, using scanning and transmission electron microscopy, and tensile measurements. Specimens (50 mm long and 6 mm wide gauge sections) were punched out from an Al-6063 23% cold worked tubes, which had been exposed to prolonged neutron irradiation of up to 4.5 x 10{sup 25} thermal neutrons/m{sup 2} (E < 0.625 eV). The temperature ranged between 41 and 52 C. The tensile specimens were then tensioned till fracture in an Instron tensiometer with strain rate of 2 x 10{sup -3} s{sup -1}. The uniform elongation and the ultimate tensile strength increase as functions of fluence. Metallographic examination and fractography reveal a decrease in the local area reduction of the final fracture necking. This reduction is accompanied with a morphology transition from ductile transgranular shear rupture to a combination of transgranular shear with intergranular dimpled rupture. The intergranular rupture area increases with fluence. No voids could be observed up to the maximum fluence. The dislocation density of cold worked Al decreases with the thermal neutron fluence. Prolonged annealing of unirradiated cold worked Al-6063 at 52 C revealed similar results. It thus appears that under our irradiation conditions the temperature during irradiation is the major factor influencing the mechanical properties and the microstructure during irradiation. (orig.). 23 refs.

  8. Mechanical properties and microstructure of neutron irradiated cold worked Al-6063 alloy

    Science.gov (United States)

    Munitz, A.; Shtechman, A.; Cotler, C.; Talianker, M.; Dahan, S.

    1998-01-01

    The impact of neutron irradiation on the mechanical properties and fracture morphology of cold worked Al-6063 were studied, using scanning and transmission electron microscopy, and tensile measurements. Specimens (50 mm long and 6 mm wide gauge sections) were punched out from an Al-6063 23% cold worked tubes, which had been exposed to prolonged neutron irradiation of up to 4.5 × 10 25 thermal neutrons/m 2 ( E < 0.625 eV). The temperature ranged between 41 and 52°C. The tensile specimens were then tensioned till fracture in an Instron tensiometer with strain rate of 2 × 10 -3 s -1. The uniform elongation and the ultimate tensile strength increase as functions of fluence. Metallographic examination and fractography reveal a decrease in the local area reduction of the final fracture necking. This reduction is accompanied with a morphology transition from ductile transgranular shear rupture to a combination of transgranular shear with intergranular dimpled rupture. The intergranular rupture area increases with fluence. No voids could be observed up to the maximum fluence. The dislocation density of cold worked Al decreases with the thermal neutron fluence. Prolonged annealing of unirradiated cold worked Al-6063 at 52°C revealed similar results. It thus appears that under our irradiation conditions the temperature during irradiation is the major factor influencing the mechanical properties and the microstructure during irradiation.

  9. Magnetization studies of YBa 2Cu 3O 7-x irradiated by fast neutrons

    Science.gov (United States)

    Wisniewski, A.; Baran, M.; Przysłupski, P.; Szymczak, H.; Pajaczkowska, A.; Pytel, B.; Pytel, K.

    1988-02-01

    Studies of the effect of fast neutron damage on the magnetic hysteresis of YBa 2Cu 3O 7-x ceramic samples subjected to fluence of neutrons of 2∗10 16 n/cm 2 up to 6∗10 17 n/cm 2 have been performed. irradiation up to dose of 1∗10 17 did not cause any change in the critical temperature. However it causes a strong increase of the magnetic hysteresis which is presumably connected with the creation of defects. The critical current density at 77 K in H = 10 k0e for the sample irradiated with the dose 1∗10 17 n/cm 2 was estimated to be 520 A/cm 2 as compared to 29 A/cm 2 for the reference non-irradiated sample, non-irradiated sample.

  10. Neutron irradiation effects on the ductile-brittle transition of ferritic/martensitic steels

    Energy Technology Data Exchange (ETDEWEB)

    Klueh, R.L.; Alexander, D.J. [Oak Ridge National Lab., TN (United States)

    1997-08-01

    Ferritic/martensitic steels such as the conventional 9Cr-1MoVNb (Fe-9Cr-1Mo-0.25V-0.06Nb-0.1C) and 12Cr-1MoVW (Fe-12Cr-1Mo-0.25V-0.5W-0.5Ni-0.2C) steels have been considered potential structural materials for future fusion power plants. The major obstacle to their use is embrittlement caused by neutron irradiation. Observations on this irradiation embrittlement is reviewed. Below 425-450{degrees}C, neutron irradiation hardens the steels. Hardening reduces ductility, but the major effect is an increase in the ductile-brittle transition temperature (DBTT) and a decrease in the upper-shelf energy, as measured by a Charpy impact test. After irradiation, DBTT values can increase to well above room temperature, thus increasing the chances of brittle rather than ductile fracture.

  11. Investigations into properties of charge traps created in CCDs by neutron and electron irradiation

    Indian Academy of Sciences (India)

    James E Brau; Olga Igonkina; Nikolai B Sinev; Jan Strube

    2007-12-01

    Our group has been investigating the effects related to radiation damage of CCDs since 1998. In a series of measurements in 2003 we found the puzzling effect of very slow filling of charge traps created by radiation damage of the silicon device. In 2005 we intended to study this phenomenon in detail. However, while in 2003 we could see all the traps created by neutron irradiation in 1998-1997 unchanged, such traps unexpectedly almost completely disappeared in 2005. We explain this as an effect of annealing induced by electron irradiation, as in 2003 we irradiated with electrons the same device irradiated with neutrons in 1997-1998. Results of the 2005 measurements are presented.

  12. Shielding design studies for a neutron irradiator system based on a 252Cf source.

    Science.gov (United States)

    da Silva, A X; Crispim, V R

    2001-01-01

    This study aims to investigate a shielding design against neutrons and gamma rays from a source of 252Cf, using Monte Carlo simulation. The shielding materials studied were borated polyethylene, borated-lead polyethylene and stainless steel. The Monte Carlo code MCNP4B was used to design shielding for 252Cf based neutron irradiator systems. By normalising the dose equivalent rate values presented to the neutron production rate of the source, the resulting calculations are independent of the intensity of the actual 252Cf source. The results show that the total dose equivalent rates were reduced significantly by the shielding system optimisation.

  13. Effect of fission neutron irradiation on the tensile and electrical properties of copper and copper alloys

    Energy Technology Data Exchange (ETDEWEB)

    Fabritsiev, S.A. [D.V. Efremov Institute, St. Petersburg (Russian Federation); Zinkle, S.J.; Rowcliffe, A.F. [Oak Ridge National Lab., TN (United States)] [and others

    1995-04-01

    The objective of this study is to evaluate the properties of several copper alloys following fission reactor irradiation at ITER-relevant temperatures of 80 to 200{degrees}C. This study provides some of the data needed for the ITER research and development Task T213. These low temperature irradiations caused significant radiation hardening and a dramatic decrease in the work hardening ability of copper and copper alloys. The uniform elongation was higher at 200{degree}C compared to 100{degree}C, but still remained below 1% for most of the copper alloys.

  14. Stochastic annealing simulation of copper under neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Heinisch, H.L. [Pacific Northwest National Lab., Richland, WA (United States); Singh, B.N. [Risoe National Lab., Roskilde (Denmark)

    1998-03-01

    This report is a summary of a presentation made at ICFRM-8 on computer simulations of defect accumulation during irradiation of copper to low doses at room temperature. The simulation results are in good agreement with experimental data on defect cluster densities in copper irradiated in RTNS-II.

  15. Separation of Protactinium from Neutron Irradiated Thorium Oxide; Separacion de Protactinio de Oxido de Torio Irradiado con Neutrones

    Energy Technology Data Exchange (ETDEWEB)

    Dominguez, G.; Gutierrez, L.; Ropero, M.

    1983-07-01

    The chemical separation of thorium and protactinium can be carried out by leaching most of the last one, about 95%, with aqueous HF from neutron irradiated thorium oxide. This leaching reaction la highly favored by the transformation reaction of the ThO{sub 2} material into ThF{sub 4}. For both reactions, leaching and transformation, the reagents concentration, agitation speed and temperature influences were studied and the activation energies were found. (Author) 18 refs.

  16. Correlation between shear punch and tensile data for neutron-irradiated aluminum alloys

    Energy Technology Data Exchange (ETDEWEB)

    Hamilton, M.L.; Edwards, D.J. [Pacific Northwest Laboratory, Richland, WA (United States); Toloczko, M.B. [Univ. of California, Santa Barbara, CA (United States)] [and others

    1995-04-01

    This work was performed to determine whether shear punch and tensile data obtained on neutron irradiated aluminum alloys exhibited the same type of relationship as had been seen in other work and to assess the validity of extrapolating the results to proton-irradiated alloys. This work was also meant to be the first of a series of similar test matrices designed to determine whether the shear punch/tensile relationship varied or was the same for different alloy classes.

  17. The effect of neutron irradiation on the mechanical properties of C/SiC composites

    Energy Technology Data Exchange (ETDEWEB)

    Shih, Chunghao [ORNL; Katoh, Yutai [ORNL; Snead, Lance Lewis [ORNL; Steinbeck, John [ORNL

    2013-01-01

    The effects of neutron irradiation to 3.5 and 9.5 dpa at 730 C on a 2D plain woven carbon fiber reinforced polymer derived SiC matrix composite are presented. For both fluences, the irradiation caused in-plane contraction and trans-plane expansion. Irradiation also caused substantial reduction in composite flexural strength (54%) and increase in flexural tangent modulus (+85%). The extents of dimensional/ mechanical property changes were greater for the higher fluence irradiated samples. Those changes suggest the instability of the polymer derived SiC matrix following irradiation. The nature of the mechanical property changes suggest increased clamping stress between the fiber and the matrix. The composite property changes are explained in terms of irradiation effects on composite constituents and are compared with carbon fiber reinforced carbon matrix composite as a reference material.

  18. The effect of neutron irradiation on the mechanical properties of C/SiC composites

    Energy Technology Data Exchange (ETDEWEB)

    Shih, Chunghao, E-mail: shihc@ornl.gov [Materials Science and Technology Division, Oak Ridge National Laboratory (United States); Katoh, Yutai, E-mail: katohy@ornl.gov [Materials Science and Technology Division, Oak Ridge National Laboratory (United States); Snead, Lance L., E-mail: sneadll@ornl.gov [Materials Science and Technology Division, Oak Ridge National Laboratory (United States); Steinbeck, John, E-mail: jws@psicorp.com [Physical Science Inc., Andover MA (United States)

    2013-08-15

    The effects of neutron irradiation to 3.5 and 9.5 dpa at 730 °C on a 2D plain woven carbon fiber reinforced polymer derived SiC matrix composite are presented. For both fluences, the irradiation caused in-plane contraction and trans-plane expansion. Irradiation also caused substantial reduction in composite flexural strength (−54%) and increase in flexural tangent modulus (+85%). The extents of dimensional/mechanical property changes were greater for the higher fluence irradiated samples. Those changes suggest the instability of the polymer derived SiC matrix following irradiation. The nature of the mechanical property changes suggest increased clamping stress between the fiber and the matrix. The composite property changes are explained in terms of irradiation effects on composite constituents and are compared with carbon fiber reinforced carbon matrix composite as a reference material.

  19. The effect of neutron irradiation on the mechanical properties of C/SiC composites

    Science.gov (United States)

    Shih, Chunghao; Katoh, Yutai; Snead, Lance L.; Steinbeck, John

    2013-08-01

    The effects of neutron irradiation to 3.5 and 9.5 dpa at 730 °C on a 2D plain woven carbon fiber reinforced polymer derived SiC matrix composite are presented. For both fluences, the irradiation caused in-plane contraction and trans-plane expansion. Irradiation also caused substantial reduction in composite flexural strength (-54%) and increase in flexural tangent modulus (+85%). The extents of dimensional/mechanical property changes were greater for the higher fluence irradiated samples. Those changes suggest the instability of the polymer derived SiC matrix following irradiation. The nature of the mechanical property changes suggest increased clamping stress between the fiber and the matrix. The composite property changes are explained in terms of irradiation effects on composite constituents and are compared with carbon fiber reinforced carbon matrix composite as a reference material.

  20. Irradiation-induced precipitates in a neutron irradiated 304 stainless steel studied by three-dimensional atom probe

    Energy Technology Data Exchange (ETDEWEB)

    Toyama, T., E-mail: ttoyama@imr.tohoku.ac.jp [International Research Center for Nuclear Materials Science, Institute for Materials Research, Tohoku University, Narita-cho 2145-2, Oarai, Ibaraki 311-1313 (Japan); Nozawa, Y. [International Research Center for Nuclear Materials Science, Institute for Materials Research, Tohoku University, Narita-cho 2145-2, Oarai, Ibaraki 311-1313 (Japan); Van Renterghem, W. [SCK-CEN, Nuclear Materials Science Institute, Boeretang 200, 2400 Mol (Belgium); Matsukawa, Y.; Hatakeyama, M.; Nagai, Y. [International Research Center for Nuclear Materials Science, Institute for Materials Research, Tohoku University, Narita-cho 2145-2, Oarai, Ibaraki 311-1313 (Japan); Al Mazouzi, A. [EDF R and D, Avenue des Renardieres Ecuelles, 77818 Moret sur Loing Cedex (France); Van Dyck, S. [SCK-CEN, Nuclear Materials Science Institute, Boeretang 200, 2400 Mol (Belgium)

    2011-11-15

    Highlights: > Irradiation-induced precipitates in a 304 stainless steel were investigated by three-dimensional atom probe. > The precipitates were found to be {gamma}' precipitates (Ni{sub 3}Si). > Post-irradiation annealing was performed to discuss the contribution of the precipitates to irradiation-hardening. - Abstract: Irradiation-induced precipitates in a 304 stainless steel, neutron-irradiated to a dose of 24 dpa at 300 deg. C in the fuel wrapper plates of a commercial pressurized water reactor, were investigated by laser-assisted three-dimensional atom probe. A high number density of 4 x 10{sup 23} m{sup -3} of Ni-Si rich precipitates was observed, which is one order of magnitude higher than that of Frank loops. The average diameter was {approx}10 nm and the average chemical composition was 40% Ni, 14% Si, 11% Cr and 32% Fe in atomic percent. Over a range of Si concentrations, the ratio of Ni to Si was {approx}3, close to that of {gamma}' precipitate (Ni{sub 3}Si). In some precipitates, Mn enrichment inside the precipitate and P segregation at the interface were observed. Post-irradiation annealing was performed to discuss the contribution of the precipitates to irradiation-hardening.

  1. Microstructure and mechanical behavior of neutron irradiated ultrafine grained ferritic steel

    Energy Technology Data Exchange (ETDEWEB)

    Alsabbagh, Ahmad, E-mail: ahalsabb@ncsu.edu [Department of Nuclear Engineering, North Carolina State University, Raleigh, NC 27695 (United States); Sarkar, Apu [Department of Nuclear Engineering, North Carolina State University, Raleigh, NC 27695 (United States); Miller, Brandon [ATR National Scientific User Facility, Idaho National Laboratory, Idaho Falls, ID 83415 (United States); Burns, Jatuporn [Center for Advanced Energy Studies, Idaho Falls, ID 83401 (United States); Squires, Leah; Porter, Douglas; Cole, James I. [ATR National Scientific User Facility, Idaho National Laboratory, Idaho Falls, ID 83415 (United States); Murty, K.L. [Department of Nuclear Engineering, North Carolina State University, Raleigh, NC 27695 (United States)

    2014-10-06

    Neutron irradiation effects on ultra-fine grain (UFG) low carbon steel prepared by equal channel angular pressing (ECAP) have been examined. Counterpart samples with conventional grain (CG) sizes have been irradiated alongside with the UFG ones for comparison. Samples were irradiated in the Advanced Test Reactor (ATR) at Idaho National Laboratory (INL) to 1.37 dpa. Atom probe tomography revealed manganese and silicon-enriched clusters in both UFG and CG steel after neutron irradiation. Mechanical properties were characterized using microhardness and tensile tests, and irradiation of UFG carbon steel revealed minute radiation effects in contrast to the distinct radiation hardening and reduction of ductility in its CG counterpart. After irradiation, micro hardness indicated increases of around 9% for UFG versus 62% for CG steel. Similarly, tensile strength revealed increases of 8% and 94% respectively for UFG and CG steels while corresponding decreases in ductility were 56% versus 82%. X-ray quantitative analysis showed that dislocation density in CG increased after irradiation while no significant change was observed in UFG steel, revealing better radiation tolerance. Quantitative correlations between experimental results and modeling were demonstrated based on irradiation induced precipitate strengthening and dislocation forest hardening mechanisms.

  2. The Effect of Combining Fast Neutron and Photon Irradiation on the Human Osteosarcoma OS-732 Cell Line

    Institute of Scientific and Technical Information of China (English)

    Linchun Feng; Lin Ma; Jingxiang Huang; Dong Yang; Yingxuan Wang; Mingxue Sun; Jinhua Tang; Weike Chang; Chengxiang Liu

    2005-01-01

    OBJECTIVE To determine the lethal effect of combining fast neutron with photon radiation on the OS-732 cell line.METHODS We examined the effect of irradiation by fast neutrons, photons and a mixed beam (fast neutrons plus photons) on the lethality and colony forming ability of the OS-732 cell line at different times.RESULTS Following a single irradiation close, the lethality was markedly strong at 24, 48 and 72 h in the group treated with fast neutrons alone and in the mixed beam group in which there was a high proportion of fast neutrons.CONCLUSION The lethal effect of a fast neutron and mixed beam with a high proportion of fast neutrons on the OS-732 cell line is highly significant. These studies provide guidance for the clinical application of fast neutrons for osteosarcoma treatment.

  3. Monte-Carlo investigation of radiation beam quality of the CRNA neutron irradiator for calibration purposes

    Energy Technology Data Exchange (ETDEWEB)

    Mazrou, Hakim, E-mail: mazrou_h@crna.d [Centre de Recherche Nucleaire d' Alger (CRNA), 02 Boulevard Frantz, Fanon, B.P. 399, Alger-RP 16000 (Algeria); Sidahmed, Tassadit [Centre de Recherche Nucleaire d' Alger (CRNA), 02 Boulevard Frantz, Fanon, B.P. 399, Alger-RP 16000 (Algeria); Allab, Malika [Faculte de Physique, Universite des Sciences et de la Technologie de Houari-Boumediene (USTHB), 16111, Alger (Algeria)

    2010-10-15

    An irradiation system has been acquired by the Nuclear Research Center of Algiers (CRNA) to provide neutron references for metrology and dosimetry purposes. It consists of an {sup 241}Am-Be radionuclide source of 185 GBq (5 Ci) activity inside a cylindrical steel-enveloped polyethylene container with radially positioned beam channel. Because of its composition, filled with hydrogenous material, which is not recommended by ISO standards, we expect large changes in the physical quantities of primary importance of the source compared to a free-field situation. Thus, the main goal of the present work is to fully characterize neutron field of such special delivered set-up. This was conducted by both extensive Monte-Carlo calculations and experimental measurements obtained by using BF{sub 3} and {sup 3}He based neutron area dosimeters. Effects of each component present in the bunker facility of the Algerian Secondary Standard Dosimetry Laboratory (SSDL) on the energy neutron spectrum have been investigated by simulating four irradiation configurations and comparison to the ISO spectrum has been performed. The ambient dose equivalent rate was determined based upon a correct estimate of the mean fluence to ambient dose equivalent conversion factors at different irradiations positions by means of a 3-D transport code MCNP5. Finally, according to practical requirements established for calibration purposes an optimal irradiation position has been suggested to the SSDL staff to perform, in appropriate manner, their routine calibrations.

  4. Neutron irradiation and damage assessment of plastic scintillators of the Tile Calorimeter

    Science.gov (United States)

    Mdhluli, J. E.; Mellado, B.; Sideras-Haddad, E.

    2017-01-01

    Following the comparative study of proton induced radiation damage on various plastic scintillator samples from the ATLAS-CERN detector, a study on neutron irradiation and damage assessment on the same type of samples will be conducted. The samples will be irradiated with different dose rates of neutrons produced in favourable nuclear reactions using a radiofrequency linear particle accelerator as well as from the SAFARI nuclear reactor at NECSA. The MCNP 5 code will be utilized in simulating the neutron transport for determining the dose rate. Light transmission and light yield tests will be performed in order to assess the radiation damage on the scintillators. In addition, Raman spectroscopy and Electron Paramagnetic Resonance (EPR) analysis will be used to characterize the samples after irradiation. The project aims to extent these studies to include radiation assessment damage of any component that processes the scintillating light and deteriorates the quantum efficiency of the Tilecal detector, namely, photomultiplier tubes, wavelength shifting optical fibres and the readout electronics. They will also be exposed to neutron irradiation and the damage assessed in the same manner.

  5. Magnetic structure at low temperatures in FeGe{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Babu, P. D., E-mail: pdbabu@csr.res.in [UGC-DAE-Consortium for Scientific Research, Mumbai Centre, BARC, Mumbai-400085 (India); Mishra, P. K.; Dube, V.; Ravikumar, G. [Technical Physics Division, Bhabha Atomic Research Centre, Mumbai-400085 (India); Mishra, R. [Chemistry, Division, Bhabha Atomic Research Centre, Mumbai-400085 (India); Sastry, P. U. [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai-400085 (India)

    2014-04-24

    Magnetic phase of FeGe{sub 2} intermetallic is studied using low-temperature neutron diffraction and DC magnetization. Zero-magnetic-field neutron scattering data shows the presence of an antiferromagnetic phase in the low temperature range. We find the evidence of the presence of a ferromagnetic order overriding on the predominantly antiferromagnetic phase at low temperatures.

  6. Swelling behavior detection of irradiated U-10Zr alloy fuel using indirect neutron radiography

    Science.gov (United States)

    Sun, Yong; Huo, He-yong; Wu, Yang; Li, Jiangbo; Zhou, Wei; Guo, Hai-bing; Li, Hang; Cao, Chao; Yin, Wei; Wang, Sheng; Liu, Bin; Feng, Qi-jie; Tang, Bin

    2016-11-01

    It is hopeful that fusion-fission hybrid energy system will become an effective approach to achieve long-term sustainable development of fission energy. U-10Zr alloy (which means the mass ratio of Zr is 10%) fuel is the key material of subcritical blanket for fusion-fission hybrid energy system which the irradiation performance need to be considered. Indirect neutron radiography is used to detect the irradiated U-10Zr alloy because of the high residual dose in this paper. Different burnup samples (0.1%, 0.3%, 0.5% and 0.7%) have been tested with a special indirect neutron radiography device at CMRR (China Mianyang Research Reactor). The resolution of the device is better than 50 μm and the quantitative analysis of swelling behaviors was carried out. The results show that the swelling behaviors relate well to burnup character which can be detected accurately by indirect neutron radiography.

  7. Prenatal exposure to gamma/neutron irradiation: Sensorimotor alterations and paradoxical effects on learning

    Energy Technology Data Exchange (ETDEWEB)

    Di Cicco, D.; Antal, S.; Ammassari-Teule, M. (Istituto di Psicobiologia e Psicofarmacologia del CNR, Rome (Italy))

    1991-01-01

    The effects of prenatal exposure on gamma/neutron radiations (0.5 Gy at about the 18th day of fetal life) were studied in a hybrid strain of mice (DBA/Cne males x C57BL/Cne females). During ontogeny, measurements of sensorimotor reflexes revealed in prenatally irradiated mice (1) a delay in sensorial development, (2) deficits in tests involving body motor control, and (3) a reduction of both motility and locomotor activity scores. In adulthood, the behaviour of prenatally irradiated and control mice was examined in the open field test and in reactivity to novelty. Moreover, their learning performance was compared in several situations. The results show that, in the open field test, only rearings were more frequent in irradiated mice. In the presence of a novel object, significant sex x treatment interactions were observed since ambulation and leaning against the novel object increased in irradiated females but decreased in irradiated males. Finally, when submitted to different learning tasks, irradiated mice were impaired in the radial maze, but paradoxically exhibited higher avoidance scores than control mice, possibly because of their low pain thresholds. Taken together, these observations indicate that late prenatal gamma/neutron irradiation induces long lasting alterations at the sensorimotor level which, in turn, can influence learning abilities of adult mice.

  8. Nano-scale chemical evolution in a proton-and neutron-irradiated Zr alloy

    Science.gov (United States)

    Harte, Allan; Topping, M.; Frankel, P.; Jädernäs, D.; Romero, J.; Hallstadius, L.; Darby, E. C.; Preuss, M.

    2017-04-01

    Proton-and neutron-irradiated Zircaloy-2 are compared in terms of the nano-scale chemical evolution within second phase particles (SPPs) Zr(Fe,Cr)2 and Zr2(Fe,Ni). This is accomplished through ultra-high spatial resolution scanning transmission electron microscopy and the use of energy-dispersive X-ray spectroscopic methods. Fe-depletion is observed from both SPP types after irradiation with both irradiative species, but is heterogeneous in the case of Zr(Fe,Cr)2, predominantly from the edge region, and homogeneously in the case of Zr2(Fe,Ni). Further, there is evidence of a delay in the dissolution of the Zr2(Fe,Ni) SPP with respect to the Zr(Fe,Cr)2. As such, SPP dissolution results in matrix supersaturation with solute under both irradiative species and proton irradiation is considered well suited to emulate the effects of neutron irradiation in this context. The mechanisms of solute redistribution processes from SPPs and the consequences for irradiation-induced growth phenomena are discussed.

  9. Irradiation creep in austenitic and ferritic steels irradiated in a tailored neutron spectrum to induce fusion reactor levels of helium

    Energy Technology Data Exchange (ETDEWEB)

    Grossbeck, M.L.; Gibson, L.T. [Oak Ridge National Laboratory, TN (United States); Jitsukawa, S.

    1996-04-01

    Six austenitic stainless steels and two ferritic alloys were irradiated sequentially in two research reactors where the neutron spectrum was tailored to produce a He production rate typical of a fusion device. Irradiation began in the Oak Ridge Research Reactor where an atomic displacement level of 7.4 dpa was achieved and was then transferred to the High Flux Isotope Reactor for the remainder of the irradiation to a total displacement level of 19 dpa. Temperatures of 60 and 330{degree}C are reported on. At 330{degree}C irradiation creep was found to be linear in stress and fluence with rates in the range of 1.7 - 5.5 x 10{sup -4}% MPa{sup -1} dpa{sup -1}. Annealed and cold-worked materials exhibited similar creep rates. There is some indication that austenitic alloys with TiC or TiO precipitates had a slightly higher irradiation creep rate than those without. The ferritic alloys HT-9 and Fe-16Cr had irradiatoin creep rates about 0.5 x 10{sup -4}% MPa{sup -1} dpa{sup -1}. No meaningful data could be obtained from the tubes irradiated at 60{degree}C because of damage to the tubes.

  10. Displacement damage effects on CMOS APS image sensors induced by neutron irradiation from a nuclear reactor

    Directory of Open Access Journals (Sweden)

    Zujun Wang

    2014-07-01

    Full Text Available The experiments of displacement damage effects on CMOS APS image sensors induced by neutron irradiation from a nuclear reactor are presented. The CMOS APS image sensors are manufactured in the standard 0.35 μm CMOS technology. The flux of neutron beams was about 1.33 × 108 n/cm2s. The three samples were exposed by 1 MeV neutron equivalent-fluence of 1 × 1011, 5 × 1011, and 1 × 1012 n/cm2, respectively. The mean dark signal (KD, dark signal spike, dark signal non-uniformity (DSNU, noise (VN, saturation output signal voltage (VS, and dynamic range (DR versus neutron fluence are investigated. The degradation mechanisms of CMOS APS image sensors are analyzed. The mean dark signal increase due to neutron displacement damage appears to be proportional to displacement damage dose. The dark images from CMOS APS image sensors irradiated by neutrons are presented to investigate the generation of dark signal spike.

  11. Low temperature formation of ferroelectric PbTiO3 films by laser ablation with 2nd laser irradiation; Reiki hikari laser heiyo laser ablation ho ni yoru kyoyudentai PbTiO3 usumaku no teion keisei

    Energy Technology Data Exchange (ETDEWEB)

    Tabata, H.; Kawai, T. [Osaka University, Osaka (Japan)

    1997-08-20

    The unique advantage of the pulsed laser deposition is its ability to produce highly oriented stoichiometric films at a low substrate temperature. Ferroelectric PbTiO3 thin films have been formed using 2nd laser assisted laser ablaion technique at low temperature, i.e., 350degC, on Sr7iO3 single-crystal substrates and Pt/MgO electrodes. The second laser irradiation at the substrate surface is quite effective for crystallization of the films at low substrate temperature below 400degC. The suitable energy density (fluence) of the irradiation laser is in the range of 30-100 mJ/cm{sup 2}. X-ray diffraction patterns of PbTiO3 thin films show c-axis orientation, with a rocking angle of 1.0 - 0.5deg. These films exhibit ferroelectric hysteresis loop. The dielectric constant and remanent polalyzation of the PbTiO3 films are in the range of 120-150 and 60-80 {mu}C/cm{sup 2}, respectively. 31 refs., 10 figs., 1 tab.

  12. Induction of external abnormalities in offspring of male mice irradiated with [sup 252]Cf neutron

    Energy Technology Data Exchange (ETDEWEB)

    Kurishita, Akihiro; Ono, Tetsuya; Mori, Yuriko (Tohoku University School of Medicine, Sendai (Japan). Department of Radiation Research); Okada, Shigefumi (Kyoto University (Japan). Radiation Biology Center); Sawada, Syozo (Hiroshima Univ. (Japan). Research Inst. for Nuclear Medicine and Biology)

    1992-08-01

    To assess the genetic effects of fission neutron, the induction of external malformations was studied in F[sub 1] fetuses after F[sub 0] male mice were irradiated. Male mice of the ICR:MCH strain were irradiated with [sup 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[sup -4]/gamete/cGy based on the linear regression. These results indicated that fission neutron effectively induces external abnormalities in F[sub 1] fetuses after spermatogonial irradiation. (author). 29 refs.; 1 fig.; 2 tabs.

  13. Helium release from neutron-irradiated Li{sub 2}O single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Yamaki, Daiju; Tanifuji, Takaaki; Noda, Kenji [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-03-01

    Helium release behavior in post-irradiation heating tests was investigated for Li{sub 2}O single crystals which had been irradiated with thermal neutrons in JRR-4 and JRR-2, and fast neutrons in FFTF. It is clarified that the helium release curves from JRR-4 and JRR-2 specimens consists of only one broad peak. From the dependence of the peak temperatures on the neutron fluence and the crystal diameter, and the comparison with the results obtained for sintered pellets, it is considered that the helium generated in the specimen is released through the process of bulk diffusion with trapping by irradiation defects such as some defect clusters. For the helium release from FFTF specimens, two broad peaks were observed in the release curves. It is considered to suggest that two different diffusion paths exist for helium migration in the specimen, that is, bulk diffusion and diffusion through the micro-crack due to the heavy irradiation. In addition, helium bubble formation after irradiation due to the high temperature over 800K is suggested. (J.P.N.)

  14. Modeling of helium bubble nucleation and growth in neutron irradiated boron doped RAFM steels

    Energy Technology Data Exchange (ETDEWEB)

    Dethloff, Christian, E-mail: christian.dethloff@kit.edu [Karlsruhe Institute of Technology (KIT), Institute for Applied Materials, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Gaganidze, Ermile [Karlsruhe Institute of Technology (KIT), Institute for Applied Materials, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Svetukhin, Vyacheslav V. [Ulyanovsk State University, Leo Tolstoy Str. 42, 432970 Ulyanovsk (Russian Federation); Aktaa, Jarir [Karlsruhe Institute of Technology (KIT), Institute for Applied Materials, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany)

    2012-07-15

    Reduced activation ferritic/martensitic (RAFM) steels are promising candidates for structural materials in future fusion technology. In addition to other irradiation defects, the transmuted helium is believed to strongly influence material hardening and embrittlement behavior. A phenomenological model based on kinetic rate equations is developed to describe homogeneous nucleation and growth of helium bubbles in neutron irradiated RAFM steels. The model is adapted to different {sup 10}B doped EUROFER97 based heats, which already had been studied in past irradiation experiments. Simulations yield bubble size distributions, whereby effects of helium generation rate, surface energy, helium sinks and helium density are investigated. Peak bubble diameters under different conditions are compared to preliminary microstructural results on irradiated specimens. Helium induced hardening was calculated by applying the Dispersed Barrier Hardening model to simulated cluster size distributions. Quantitative microstructural investigations of unirradiated and irradiated specimens will be used to support and verify the model.

  15. Structure and Spatial Distribution of Ge Nanocrystals Subjected to Fast Neutron Irradiation

    Directory of Open Access Journals (Sweden)

    Alexander N. Ionov

    2011-07-01

    Full Text Available The influence of fast neutron irradiation on the structure and spatial distribution of Ge nanocrystals (NC embedded in an amorphous SiO2 matrix has been studied. The investigation was conducted by means of laser Raman Scattering (RS, High Resolution Transmission Electron Microscopy (HR-TEM and X-ray photoelectron spectroscopy (XPS. The irradiation of Ge- NC samples by a high dose of fast neutrons lead to a partial destruction of the nanocrystals. Full reconstruction of crystallinity was achieved after annealing the radiation damage at 8000C, which resulted in full restoration of the RS spectrum. HR-TEM images show, however, that the spatial distributions of Ge-NC changed as a result of irradiation and annealing. A sharp decrease in NC distribution towards the SiO2 surface has been observed. This was accompanied by XPS detection of Ge oxides and elemental Ge within both the surface and subsurface region.

  16. Gamma and neutron massive irradiation tests of the ATLAS MDT chambers

    Energy Technology Data Exchange (ETDEWEB)

    Meoni, Evelin [Dipartimento di Fisica, Universita degli Studi della Calabria and INFN, Cosenza (Italy)]. E-mail: meoni@fis.unical.it; Branchini, Paolo [Dipartimento di Fisica, Universita Roma Tre and INFN Sezione di Roma III, Rome (Italy); Di Luise, Silvestro [Dipartimento di Fisica, Universita Roma Tre and INFN Sezione di Roma III, Rome (Italy); Graziani, Enrico [Dipartimento di Fisica, Universita Roma Tre and INFN Sezione di Roma III, Rome (Italy); La Rotonda, Laura [Dipartimento di Fisica, Universita degli Studi della Calabria and INFN, Cosenza (Italy); Mazzotta, Concetta [Dipartimento di Fisica, Universita degli Studi della Calabria and INFN, Cosenza (Italy); Morello, Gianfranco [Dipartimento di Fisica, Universita degli Studi della Calabria and INFN, Cosenza (Italy); Passeri, Antonio [Dipartimento di Fisica, Universita Roma Tre and INFN Sezione di Roma III, Rome (Italy); Petrucci, Fabrizio [Dipartimento di Fisica, Universita Roma Tre and INFN Sezione di Roma III, Rome (Italy); Policicchio, Antonio [Dipartimento di Fisica, Universita degli Studi della Calabria and INFN, Cosenza (Italy); Salvatore, Daniela [Dipartimento di Fisica, Universita degli Studi della Calabria and INFN, Cosenza (Italy); Schioppa, Marco [Dipartimento di Fisica, Universita degli Studi della Calabria and INFN, Cosenza (Italy); Tonazzo, Alessandra [Dipartimento di Fisica, Universita Roma Tre and INFN Sezione di Roma III, Rome (Italy)

    2007-03-01

    MDT chambers, the precision tracking system of the ATLAS muon spectrometer, have to operate for 10 years in the harsh LHC background environment mainly due to low energy photons and neutrons. The expected overall maximum count rate is 500Hz/cm{sup 2}. Moreover the upgrades for S-LHC will involve fluxes ten times higher than that at LHC. To study the behavior of MDT chambers under massive irradiation of gammas and neutrons at level of S-LHC, three extensive tests were performed at the ENEA-Casaccia Research Centre Facilities, irradiating several test detectors. The results about the drift properties, gas gain and tracking performances, both at high rates and after massive irradiation, are given.

  17. Influence of rapid thermal process on intrinsic gettering in fast neutron irradiated Czochralski silicon

    Institute of Scientific and Technical Information of China (English)

    CHEN Gui-feng; LI Yang-xian; LI Xing-hua; CAI Li-li; MA Qiao-yun; NIU Ping-juan; NIU Sheng-li; CHEN Dong-feng

    2006-01-01

    A rapid thermal process (RTP) was first introduced into the intrinsic gettering (IG) processes of fast neutron irradiated Czochralski (CZ) silicon. The effect of RTP conditions on bulk microdefects (BMDs) and denuded zone (DZ) was investigated. Fourier transform infrared absorption spectrometer (FTIR) was used to measure the concentration of interstitial oxygen ([Oi]). Bulk microdefects were observed by optical microscope. The results show that,according to the variation of [Oi],it is found that RTP doesn't change the processes of oxygen precipitation in fast neutron irradiated Czochralski silicon. Perfect denuded zone,dense oxygen precipitates and defects form in the bulk of irradiated samples. With increasing temperature of RTP,the width of denuded zone decreases. Increasing RTP cooling rate,the density of Bulk microdefects increases. DZ forms in the sample that annealed in nitrogen atmosphere.

  18. Results from the CDE phase activity on neutron dosimetry for the international fusion materials irradiation facility test cell

    CERN Document Server

    Esposito, B; Maruccia, G; Petrizzi, L; Bignon, G; Blandin, C; Chauffriat, S; Lebrun, A; Recroix, H; Trapp, J P; Kaschuck, Y

    2000-01-01

    The international fusion materials irradiation facility (IFMIF) project deals with the study of an accelerator-based, deuterium-lithium source, producing high energy neutrons at sufficient intensity and irradiation volume to test samples of candidate materials for fusion energy reactors. IFMIF would also provide calibration and validation of data from fission reactor and other accelerator based irradiation tests. This paper describes the activity on neutron/gamma dosimetry (necessary for the characterization of the specimens' irradiation) performed in the frame of the IFMIF conceptual design evaluation (CDE) neutronics tasks. During the previous phase (conceptual design activity (CDA)) the multifoil activation method was proposed for the measurement of the neutron fluence and spectrum and a set of suitable foils was defined. The cross section variances and covariances of this set of foils have now been used for tests on the sensitivity of the IFMIF neutron spectrum determination to cross section uncertainties...

  19. Electrical characterization of commercial NPN bipolar junction transistors under neutron and gamma irradiation

    Directory of Open Access Journals (Sweden)

    OO Myo Min

    2014-01-01

    Full Text Available Electronics components such as bipolar junction transistors, diodes, etc. which are used in deep space mission are required to be tolerant to extensive exposure to energetic neutrons and ionizing radiation. This paper examines neutron radiation with pneumatic transfer system of TRIGA Mark-II reactor at the Malaysian Nuclear Agency. The effects of the gamma radiation from Co-60 on silicon NPN bipolar junction transistors is also be examined. Analyses on irradiated transistors were performed in terms of the electrical characteristics such as current gain, collector current and base current. Experimental results showed that the current gain on the devices degraded significantly after neutron and gamma radiations. Neutron radiation can cause displacement damage in the bulk layer of the transistor structure and gamma radiation can induce ionizing damage in the oxide layer of emitter-base depletion layer. The current gain degradation is believed to be governed by the increasing recombination current in the base-emitter depletion region.

  20. Neutron capture effects in lunar gadolinium and the irradiation histories of some lunar rocks.

    Science.gov (United States)

    Lugmair, G. W.; Marti, K.

    1971-01-01

    The Gd isotopic composition in 19 lunar rock and soil samples from three Apollo sites is reported. The analytical techniques and the high precision mass spectrometric measurements are discussed. Enrichments in the Gd-158 oxide to G-157 oxide ratio due to neutron capture range up to 0.75%. Integrated 'thermal' neutron fluxes derived from the isotopic anomalies of Gd are compared with spallation Kr data from aliquot samples to construct a model which gives both average cosmic-ray irradiation depths and effective neutron exposure ages for some rocks. Rock 14310 is the first lunar sample where Kr anomalies due to resonance neutron capture in Br are observed. A Kr-81/Kr exposure age of 262 (plus or minus 7)m.y. is calculated for this rock.

  1. Impact property of low-activation vanadium alloy after laser welding and heavy neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Nagasaka, Takuya, E-mail: nagasaka@nifs.ac.jp [National Institute for Fusion Science, Toki, Gifu (Japan); The Graduate University for Advanced Studies, Toki, Gifu (Japan); Muroga, Takeo [National Institute for Fusion Science, Toki, Gifu (Japan); The Graduate University for Advanced Studies, Toki, Gifu (Japan); Watanabe, Hideo [Research Institute for Applied Mechanics, Kyushu University, Kasuga (Japan); Miyazawa, Takeshi [The Graduate University for Advanced Studies, Toki, Gifu (Japan); Yamazaki, Masanori [International Research Center for Nuclear Materials Science, Institute for Materials Research, Tohoku University, Oarai, Ibaraki (Japan); Shinozaki, Kenji [Department of Mechanical System Engineering, Graduate School of Engineering, Hiroshima University, Higashi Hiroshima (Japan)

    2013-11-15

    Weld specimens of the reference low activation vanadium alloy, NIFS-HEAT-2, were irradiated up to a neutron fluence of 1.5 × 10{sup 25} n m{sup −2} (E > 0.1 MeV) (1.2 dpa) at 670 K and 1.3 × 10{sup 26} n m{sup −2} (5.3 dpa) at 720 K in the JOYO reactor in Japan. The base metal exhibited superior irradiation resistance with the ductile-to-brittle transition temperature (DBTT) much lower than room temperature (RT) for both irradiation conditions. The weld metal kept the DBTT below RT after the 1.2 dpa irradiation; however, it showed enhanced irradiation embrittlement with much higher DBTT than RT after the 5.3 dpa irradiation. The high DBTT for the weld metal was effectively recovered by a post-irradiation annealing at 873 K for 1 h. Mechanisms of the irradiation embrittlement and its recovery are discussed, based on characterization of the radiation defects and irradiation-induced precipitation.

  2. Low-Temperature Supercapacitors

    Science.gov (United States)

    Brandon, Erik J.; West, William C.; Smart, Marshall C.

    2008-01-01

    An effort to extend the low-temperature operational limit of supercapacitors is currently underway. At present, commercially available non-aqueous supercapacitors are rated for a minimum operating temperature of -40 C. A capability to operate at lower temperatures would be desirable for delivering power to systems that must operate in outer space or in the Polar Regions on Earth. Supercapacitors (also known as double-layer or electrochemical capacitors) offer a high power density (>1,000 W/kg) and moderate energy density (about 5 to 10 Wh/kg) technology for storing energy and delivering power. This combination of properties enables delivery of large currents for pulsed applications, or alternatively, smaller currents for low duty cycle applications. The mechanism of storage of electric charge in a supercapacitor -- at the electrical double-layer formed at a solid-electrode/liquid-electrolyte interface -- differs from that of a primary or secondary electrochemical cell (i.e., a battery) in such a manner as to impart a long cycle life (typically >10(exp 6) charge/discharge cycles).

  3. Optical absorption of neutron-irradiated silica fibers

    Energy Technology Data Exchange (ETDEWEB)

    Cooke, D.W.; Farnum, E.H.; Bennett, B.L. [Los Alamos National Lab., NM (United States)

    1996-10-01

    Induced-loss spectra of silica-based optical fibers exposed to high (10{sup 23} n-m{sup {minus}2}) and low (10{sup 21} n-m{sup {minus}2}) fluences of neutrons at the Los Alamos Spallation Radiation Effects Facility (LASREF) have been measured. Two types of fibers consisting of a pure fused silica core with fluorine-doped ({approximately}4 mole %) cladding were obtained from Fiberguide Industries and used in the as-received condition. Anhydroguide{trademark} and superguide{trademark} fibers contained less than 1 ppm, and 600 to 800 ppm of OH, respectively. The data suggest that presently available silica fibers can be used in plasma diagnostics, but the choice and suitability depends upon the spectral region of interest. Low-OH content fibers can be used for diagnostic purposes in the interval {approximately}800 to 1400 mn if the exposure is to high-fluence neutrons. For low-fluence neutron exposures, the low-OH content fibers are best suited for use in the interval {approximately}800 to 2000 nm, and the high-OH content fibers are the choice for the interval {approximately}400 to 800 nm.

  4. Investigations of void formation in neutron irradiated iron and F82H steel

    DEFF Research Database (Denmark)

    Eldrup, Morten Mostgaard; Singh, Bachu Narain

    2002-01-01

    In the present work pure iron and low activation steel F82H have been neutron irradiated at temperatures in the interval 50 deg.C - 350 deg.C to a dose of 0.23 dpa (displacements per atom). The formation of defects has been investigated by the use ofpositron annihilation spectroscopy (PAS......). In addition iron has been irradiated to different doses in the range 0.01 - 0.4 dpa at 50oC and 100oC and the dose dependence of the electrical conductivity determined. The results demonstrated that theformation of voids takes place during neutron irradiation of pure iron in the whole temperature range....... For irradiation temperatures of 50 deg.C and 100 deg.C also a high density of micro-voids was observed. Voids and micro-voids were also detected in lowactivation F82H steel for a low irradiation temperature (50 deg.C), while for irradiation close to the temperature of annealing stage V (250 deg.C), no voids...

  5. Synergistic effect of mixed neutron and gamma irradiation in bipolar operational amplifier OP07

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Liu, E-mail: liuyan@nint.ac.cn [State Key Laboratory of Intense Pulsed Irradiation Simulation and Effect, Northwest Institute of Nuclear Technology, P.O.Box 69-10, Xi’an 710024 (China); School of Nuclear Science and Technology, Xi’an Jiaotong University, Xi’an 710049 (China); Wei, Chen; Shanchao, Yang; Xiaoming, Jin [State Key Laboratory of Intense Pulsed Irradiation Simulation and Effect, Northwest Institute of Nuclear Technology, P.O.Box 69-10, Xi’an 710024 (China); Chaohui, He [School of Nuclear Science and Technology, Xi’an Jiaotong University, Xi’an 710049 (China)

    2016-09-21

    This paper presents the synergistic effects in bipolar operational amplifier OP07. The radiation effects are studied by neutron beam, gamma ray, and mixed neutron/gamma ray environments. The characterateristics of the synergistic effects are studied through comparison of different experiment results. The results show that the bipolar operational amplifier OP07 exhibited significant synergistic effects in the mixed neutron and gamma irradiation. The bipolar transistor is identified as the most radiation sensitive unit of the operational amplifier. In this paper, a series of simulations are performed on bipolar transistors in different radiation environments. In the theoretical simulation, the geometric model and calculations based on the Medici toolkit are built to study the radiation effects in bipolar components. The effect of mixed neutron and gamma irradiation is simulated based on the understanding of the underlying mechanisms of radiation effects in bipolar transistors. The simulated results agree well with the experimental data. The results of the experiments and simulation indicate that the radiation effects in the bipolar devices subjected to mixed neutron and gamma environments is not a simple combination of total ionizing dose (TID) effects and displacement damage. The data suggests that the TID effect could enhance the displacement damage. The synergistic effect should not be neglected in complex radiation environments.

  6. Subtask 12F3: Effects of neutron irradiation on tensile properties of vanadium-base alloys

    Energy Technology Data Exchange (ETDEWEB)

    Loomis, B.A.; Chung, H.M.; Smith, D.L. [Argonne National Lab., IL (United States)

    1995-03-01

    The objective of this work is to determine the effects of neutron irradiation on the tensile properties of candidate vanadium-base alloys. Vanadium-base alloys of the V-Cr-Ti system are attractive candidates for use as structural materials in fusion reactors. The current focus of the U.S. program of research on these alloys is on the V-(4-6)Cr-(3-6)Ti-(0.05-0.1)Si (in wt.%) alloys. In this paper, we present experimental results on the effects of neutron irradiation on tensile properties of selected candidate alloys after irradiation at 400{degrees}C-600{degrees}C in lithium in fast fission reactors to displacement damages of up to {approx}120 displacement per atom (dpa). Effects of irradiation temperature and dose on yield and ultimate tensile strengths and uniform and total elongations are given for tensile test temperatures of 25{degrees}C, 420{degrees}C, 500{degrees}, and 600{degrees}C. Effects of neutron damage on tensile properties of the U.S. reference alloy V-4Cr-4Ti are examined in detail. 7 refs., 10 figs., 1 tab.

  7. Deuterium trapping at defects created with neutron and ion irradiations in tungsten

    Energy Technology Data Exchange (ETDEWEB)

    Y. Hatano; M. Shimada; T. Otsuka; Y. Oya; V.Kh. Alimov; M. Hara; J. Shi; M. Kobayashi; T. Oda; G. Cao; K. Okuno; T. Tanaka; K. Sugiyama; J. Roth; B. Tyburska-Püschel; J. Dorner; N. Yoshida; N. Futagami; H. Watanabe; M. Hatakeyama; H. Kurishita; M. Sokolov; Y. Katoh

    2013-07-01

    The effects of neutron and ion irradiations on deuterium (D) retention in tungsten (W) were investigated. Specimens of pure W were irradiated with neutrons to 0.3 dpa at around 323 K and then exposed to high-flux D plasma at 473 and 773 K. The concentration of D significantly increased by neutron irradiation and reached 0.8 at% at 473 K and 0.4 at% at 773 K. Annealing tests for the specimens irradiated with 20 MeV W ions showed that the defects which play a dominant role in the trapping at high temperature were stable at least up to 973 K, while the density decreased at temperatures equal to or above 1123 K. These observations of the thermal stability of traps and the activation energy for D detrapping examined in a previous study (˜1.8 eV) indicated that the defects which contribute predominantly to trapping at 773 K were small voids. The higher concentration of trapped D at 473 K was explained by additional contributions of weaker traps. The release of trapped D was clearly enhanced by the exposure to atomic hydrogen at 473 K, though higher temperatures are more effective for using this effect for tritium removal in fusion reactors.

  8. Point defects in 4H–SiC epilayers introduced by neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Hazdra, Pavel, E-mail: hazdra@fel.cvut.cz [Department of Microelectronics, Faculty of Electrical Engineering, Czech Technical University in Prague, Technická 2, CZ-16627 Prague 6 (Czech Republic); Záhlava, Vít [Department of Microelectronics, Faculty of Electrical Engineering, Czech Technical University in Prague, Technická 2, CZ-16627 Prague 6 (Czech Republic); Vobecký, Jan [Department of Microelectronics, Faculty of Electrical Engineering, Czech Technical University in Prague, Technická 2, CZ-16627 Prague 6 (Czech Republic); ABB Switzerland Ltd., Semiconductors, Fabrikstrasse 3, CH-5600 Lenzburg (Switzerland)

    2014-05-01

    Electronic properties of radiation damage produced in 4H–SiC by neutron irradiation and its effect on electrical parameters of Junction Barrier Schottky (JBS) diodes were investigated. 4H–SiC N-epilayers, which formed the low-doped N-base of JBS power diodes, were irradiated with 1 MeV neutrons with fluences ranging from 1.3 × 10{sup 13} to 4.0 × 10{sup 14} cm{sup −2}. Radiation defects were then characterized by capacitance deep-level transient spectroscopy, I–V and C–V measurement. Results show that neutron irradiation introduces different point defects giving rise to acceptor levels lying 0.61/0.69, 0.88, 1.03, 1.08 and 1.55 eV below the SiC conduction band edge. Introduction rates of these centers are ranging from 0.64 to 4.0 cm{sup −1}. These defects have a negligible effect on blocking and dynamic characteristics of irradiated diodes. However, the acceptor character of introduced deep levels and their fast introduction deteriorate diode’s ON-state resistance already at fluences exceeding 1 × 10{sup 14} cm{sup −2}.

  9. Mechanical properties of neutron-irradiated nickel-containing martensitic steels: I. Experimental study

    Energy Technology Data Exchange (ETDEWEB)

    Klueh, R.L. [Oak Ridge National Laboratory, P.O. Box 2008, MS 6151, Oak Ridge, Tennessee 37831-6151 (United States)]. E-mail: kluehrl@ornl.gov; Hashimoto, N. [Oak Ridge National Laboratory, P.O. Box 2008, MS 6151, Oak Ridge, Tennessee 37831-6151 (United States); Sokolov, M.A. [Oak Ridge National Laboratory, P.O. Box 2008, MS 6151, Oak Ridge, Tennessee 37831-6151 (United States); Shiba, K. [Japan Atomic Energy Research Institute, Tokai-mura, Naka-gun, Tokai, Ibaraki 319-1195 (Japan); Jitsukawa, S. [Japan Atomic Energy Research Institute, Tokai-mura, Naka-gun, Tokai, Ibaraki 319-1195 (Japan)

    2006-10-15

    Tensile and Charpy specimens of 9Cr-1MoVNb (modified 9Cr-1Mo) and 12Cr-1MoVW (Sandvik HT9) steels and these steels doped with 2% Ni were irradiated at 300 and 400 deg. C in the High Flux Isotope Reactor (HFIR) up to {approx}12 dpa and at 393 deg. C in the Fast Flux Test Facility (FFTF) to {approx}15 dpa. In HFIR, a mixed-spectrum reactor (n, {alpha}) reactions of thermal neutrons with {sup 58}Ni produce helium in the steels. Little helium is produced during irradiation in FFTF. After HFIR irradiation, the yield stress of all steels increased, with the largest increases occurring for nickel-doped steels. The ductile-brittle transition temperature (DBTT) increased up to two times and 1.7 times more in steels with 2% Ni than in those without the nickel addition after HFIR irradiation at 300 and 400 deg. C, respectively. Much smaller differences occurred between these steels after irradiation in FFTF. The DBTT increases for steels with 2% Ni after HFIR irradiation were 2-4 times greater than after FFTF irradiation. Results indicated there was hardening due to helium in addition to hardening by displacement damage and irradiation-induced precipitation.

  10. Low Temperature Photoluminescence (PL) from High Electron Mobility Transistors (HEMTs)

    Science.gov (United States)

    2015-03-01

    TECHNICAL REPORT RDMR-WD-14-55 LOW TEMPERATURE PHOTOLUMINESCENCE (PL) FROM HIGH ELECTRON MOBILITY TRANSISTORS (HEMTS...DATE March 2015 3. REPORT TYPE AND DATES COVERED Final 4. TITLE AND SUBTITLE Low Temperature Photoluminescence (PL) From High Electron...temperature Photoluminescence (PL) from High Electron Mobility Transistor (HEMT) structures that have been modified by proton irradiation. The samples are

  11. Fluence dependence of defect evolution in austenitic stainless steels during fission neutron irradiation

    Science.gov (United States)

    Watanabe, H.; Muroga, T.; Yoshida, N.

    To understand microstructural evolution during fission neutron irradiation, a pure Fe-Cr-Ni ternary alloy, phosphorus-containing model austenitic stainless steels and SUS316 were irradiated in a Japanese Material Testing Reactor (JMTR) at 493 and 613 K. At 493 K, the density of defect cluster increased with the irradiation dose, but there was no significant change in loop density and loop size among all the materials. At 613 K, on the other hand, interstitial type dislocation loops and phosphides were formed in pure ternary and phosphorus-containing alloys, respectively, by an early stage of irradiation. These results suggest that the defect cluster formation at 493 and 613 K is mainly controlled by the cascade damage and long-range migration of free point defects, respectively.

  12. Phase transformations in lithium aluminates irradiated with neutrons; Transformaciones de fase en aluminatos de litio irradiados con neutrones

    Energy Technology Data Exchange (ETDEWEB)

    Carrera, L.M.; Delfin L, A.; Urena N, F.; Basurto, R. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico); Bosch, P. [UAM-I, 09340 Mexico D.F. (Mexico)

    2003-07-01

    The lithium aluminate like candidate to be used in the coverings producers of tritium in the fusion nuclear reactors, presents high resistance to the corrosion to the one to be stuck to structural materials as special steels. However, the crystallographic changes that take place in the cover that is continually subjected to irradiation with neutrons, can alter its resistance to the corrosion. In this work the changes of crystalline structure are shown that they present two types of nano structures of lithium aluminates, subjected to an average total dose 7.81 x 10{sup 8} Gy in the fixed irradiation system of capsules of the one TRIGA Mark lll nuclear reactor of the Nuclear Center of Mexico. The studied nano structures presented only phase transformations without formation of amorphous material. (Author)

  13. Development of Pneumatic Transfer Irradiation Facility (PTS no.2) for Neutron Activation Analysis at HANARO Research Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Y. S.; Moon, J. H.; Kim, S. H.; Sun, G. M.; Baek, S. Y.; Kim, H. R.; Kim, Y. J

    2008-03-15

    A pneumatic transfer irradiation system (PTS) is one of the most important facilities used during neutron irradiation of a target material for instrumental neutron activation analysis (INAA) in a research reactor. In particular, a fast pneumatic transfer system is essential for the measurement of a short half-life nuclide and a delayed neutron counting system. The pneumatic transfer irradiation system (PTS no.2) involving a manual system and an automatic system for delayed neutron activation analysis (DNAA) were reconstructed with new designs of a functional improvement at the HANARO research reactor in 2006. In this technical report, the conception, design, operation and control of PTS no.2 was described. Also the experimental results and the characteristic parameters measured by a mock-up test, a functional operation test and an irradiation test of these systems, such as the transfer time of irradiation capsule, automatic operation control by personal computer, delayed neutron counting system, the different neutron flux, the temperature of the irradiation position with an irradiation time, the radiation dose rate when the rabbit is returned, etc. are reported to provide a user information as well as a reactor's management and safety.

  14. A new irradiation method with a neutron filter for silicon neutron transmutation doping at the Japan research reactor no. 3 (JRR-3).

    Science.gov (United States)

    Komeda, Masao; Kawasaki, Kozo; Obara, Toru

    2013-04-01

    We studied a new silicon irradiation holder with a neutron filter designed to make the vertical neutron flux profile uniform. Since an irradiation holder has to be made of a low activation material, we applied aluminum blended with B4C as the holder material. Irradiation methods to achieve uniform flux with a filter are discussed using Monte-Carlo calculation code MVP. Validation of the use of the MVP code for the holder's analyses is also discussed via characteristic experiments. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Displacement Damage in Silicon Irradiated with 6- to 10-MeV Neutrons.

    Science.gov (United States)

    1977-04-01

    3. E . E . Conrad , “Considerations in Establ i sh ing a Standard for N eutron Displacement Energy Ef fec ts in Semiconductors ” , IEEE Trans. Nuci...at a tem perature s ign i f i can t ly hi gher than that during irradiation , is sufficient t~- el iminate prior thermal history as a factor in...the number and natur e of permanent defects. 22. C.E. Barnes , “ Thermal and Injection Annealing of Neutron- Irradi tsd P-Type Silicon Between 76°K and

  16. The study of neutron spectra in water bath from Pb target irradiated by 250MeV/u protons

    CERN Document Server

    Li, Yanyan; Ju, Yongqin; Ma, Fei; Zhang, Hongbin; Chen, Liang; Ge, Honglin; Luo, Peng; Zhou, Bin; Zhang, Yanbin; Li, Jianyang; Xu, Junkui; Wang, Songlin; Yang, Yongwei; Yang, Lei

    2014-01-01

    The spallation neutrons were produced by the irradiation of Pb with 250 MeV protons. The Pb target was surrounded by water which was used to slow down the emitted neutrons. The moderated neutrons in the water bath were measured by using the resonance detectors of Au, Mn and In with Cd cover. According to the measured activities of the foils, the neutron flux at different resonance energy were deduced and the epithermal neutron spectra were proposed. Corresponding results calculated with the Monte Carlo code MCNPX were compared with the experimental data to check the validity of the code.

  17. Study of damages by neutron irradiation in lithium aluminates; Estudio de danos por irradiacion neutronica en aluminatos de litio

    Energy Technology Data Exchange (ETDEWEB)

    Palacios G, O

    1999-06-01

    Lithium aluminates proposed to the production of tritium in fusion nuclear reactors, due to the thermal stability that they present as well as the behavior of the aluminium to the irradiation. As a neutron flux with profile ({approx_equal} 14 Mev) of a fusion reactor is not available. A irradiation experiment was designed in order to know the micro and nano structure damages produced by fast and thermal neutrons in two irradiation positions of the fusion nuclear reactor Triga Mark III: CT (Thermal Column) and SIFCA (System of Irradiation Fixed of Capsules). In this work samples of lithium aluminate were characterized by XRD (X-Ray Diffraction), TEM (Transmission Electron Microscopy) and SEM (Scanning Electron Microscopy). Two samples were prepared by two methods: a) coalition method and b) peroxide method. This characterization comprised original and irradiated samples. The irradiated sample amounted to 4 in total: one for each preparation method and one for each irradiation position. The object of this analysis was to correlate with the received neutron dose the damages suffered by the samples with the neutron irradiation during long periods (440 H), in their micro and nano structure aspects; in order to understand the changes as a function of the irradiation zone (with thermal and fast neutron flux) and the preparation methods of the samples and having as an antecedent the irradiation in SIFCA position by short times (2h). The obtained results are referred to the stability of {gamma} -aluminate phase, under given conditions of irradiation and defined nano structure arrangement. They also refer to the proposals of growth mechanism and nucleation of new phases. The error associated with the measurement of neutron dose is also discussed. (Author)

  18. PCC-ring induction in human lymphocytes exposed to gamma and neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Lamadrid B, A.I.; Garcia L, O. [CPHR, Calle 20 No. 4113 e/41 y 47, Playa, La Habana 11300 (Cuba); Delbos, M.; Voisin, P.; Roy, L. [Institut de Radioprotection et de Surete Nucleaire, BP 17, 92262 Fontenay-aux-Roses (France)]. e-mail: ana@cphr.edu.cu

    2006-07-01

    Dose-effect curves for dose assessment in Gamma and neutron overexposures to high doses are presented in this paper for the first time in literature. The relationships were obtained by plotting the Premature Chromosome Condensation -rings (PCC-R) frequencies in PCC Iymphocytes obtained by chemical induction with Calyculin A in vitro, with radiation doses between 5 to 25 Gy. For the elaboration of these curves 9 676 PCC cells in Gl G2 and M stages were analyzed. The results were fitted to a lineal quadratic model in Gamma irradiation. For neutron irradiation the data was fitted to a lineal quadratic model up to 10 Gy and then a markedly cell cycle arrest and saturation was observed. These curves are of particular interest for victims exposed to doses exceeding 5 Gy where it is always very difficult to estimate a dose using the conventional technique. (Author)

  19. Polarised SANS study of microstructural evolution under neutron irradiation in a martensitic steel for fusion reactors

    Energy Technology Data Exchange (ETDEWEB)

    Coppola, R.; Dewhurst, C.D.; Lindau, R.; May, R.P.; Moeslang, A.; Valli, M

    2004-03-01

    This work presents the results of polarised small-angle neutron scattering (SANS) measurements of modified martensitic steel DIN1.4914, originally developed for application in future fusion reactors (MANET steel). SANS measurements were made using the D22 instrument at the ILL Grenoble using an ad hoc polarised beam set-up. The investigated MANET samples were neutron irradiated and subsequently post-irradiation tempered to reproduce as much as possible the expected service conditions. The results, based on the analysis of the nuclear-magnetic interference, are discussed taking into account both the occurrence of Cr redistribution phenomena with correlated changes in the composition of the precipitate phases, and the growth of non-magnetic defects (He-bubbles or microvoids)

  20. Grain boundary segregation in neutron-irradiated 304 stainless steel studied by atom probe tomography

    Energy Technology Data Exchange (ETDEWEB)

    Toyama, T., E-mail: ttoyama@imr.tohoku.ac.jp [International Research Center for Nuclear Materials Science, Institute for Materials Research, Tohoku University, Oarai, Ibaraki 311-1313 (Japan); Nozawa, Y. [International Research Center for Nuclear Materials Science, Institute for Materials Research, Tohoku University, Oarai, Ibaraki 311-1313 (Japan); Van Renterghem, W. [SCK Bullet CEN, Nuclear Materials Science Institute, Boeretang 200, 2400 Mol (Belgium); Matsukawa, Y.; Hatakeyama, M.; Nagai, Y. [International Research Center for Nuclear Materials Science, Institute for Materials Research, Tohoku University, Oarai, Ibaraki 311-1313 (Japan); Al Mazouzi, A. [EDF R and D, Avenue des Renardieres Ecuelles, 77818 Moret sur Loing Cedex (France); Van Dyck, S. [SCK Bullet CEN, Nuclear Materials Science Institute, Boeretang 200, 2400 Mol (Belgium)

    2012-06-15

    Radiation-induced segregation (RIS) of solute atoms at a grain boundary (GB) in 304 stainless steel (SS), neutron-irradiated to a dose of 24 dpa at 300 Degree-Sign C in the fuel wrapper plates of a commercial pressurized water reactor, was investigated using laser-assisted atom probe tomography (APT). Ni, Si, and P enrichment and Cr and Fe depletion at the GB were evident. The full-width at half-maximum of the RIS region was {approx}3 nm for the concentration profile peaks of Ni and Si. The atomic percentages of Ni, Si, and Cr at the GB were {approx}19%, {approx}7%, and {approx}14%, respectively, in agreement with previously-reported values for neutron-irradiated SS. A high number density of intra-granular Ni-Si rich precipitates formed in the matrix. A precipitate-denuded zone with a width of {approx}10 nm appeared on both sides of the GB.

  1. Transmutants and its behaviors in heavy irradiated AlN by reactor neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Atobe, Kozo; Tashiro, Tomonori; Honda, Makoto; Fukuoka, Noboru; Matsukawa, Tokuo [Naruto Univ. of Education, Tokushima (Japan). Faculty of Science; Okada, Moritami; Nakagawa, Masuo

    1997-01-01

    Transmutant production effects on the sintered aluminum nitride have been studied by neutron heavy irradiation using X-ray photoelectron spectroscopy analysis. The specimens are irradiated with fast neutrons in the ranges of 1.0x10{sup 17} - 1.2x10{sup 20} n/cm{sup 2}. For high fluences (>10{sup 18} n/cm{sup 2}), XPS observations show Si2s (153.8 eV) and Si2p (103.3 eV) peaks in XPS spectrum. The depth profiles using Ar-ion sputtering and the chemical shift of the peak indicate that {sup 28}Si induced by {sup 27}Al (n,{gamma}) {sup 28}Al reaction and {beta}-decay of {sup 28}Al precipitates near surface as oxidized silicon. (author)

  2. The neutron irradiation effect on the mechanical properties and structure of beryllium

    Energy Technology Data Exchange (ETDEWEB)

    Fabritsiev, S.A. [D.V. Efremov Scientific Research Inst., St. Petersburg (Russian Federation); Pokrovsky, A.S.; Bagautdinov, R.M. [Scientific Research Inst. of Atomic Reactors, Dimitrovgrad (Russian Federation)

    1999-10-01

    The neutron irradiation effect on the mechanical properties and structure of beryllium are presented. Irradiation was performed in the BOR-60 reactor up to doses of 0.7--1.1 {times} 10{sup 22} n/cm{sup 2} (E > 0.1 MeV) at irradiation temperatures of 350 C, 400 C, 520 C, 780 C. Two modifications of RF beryllium, i.e., DShG-200 and TShG-56, were chosen for investigation. For irradiation at temperatures of 350--400 C Be hardening due to the accumulation of radiation defect complexes. Hardening is accompanied with a sharp drop in plasticity at T{sub test} {le} 300 C. The fracture of samples is of brittle, mainly transcrystallite, type. High-temperature irradiation (T{sub irr} = 780 C) gives rise to large helium pores over the grain boundaries and smaller pores in the grain body. Fracture is brittle and intercrystalline at T{sub test} {ge} 600 C. Helium embrittlement is also accompanied with a drop in the Be mechanical properties. The conclusion is made that the irradiation temperature range, where irradiated beryllium has a satisfactory level of properties, is rather narrow: 300 C {le} T {le} 500 C.

  3. Modeling of displacement damage in silicon carbide detectors resulting from neutron irradiation

    Science.gov (United States)

    Khorsandi, Behrooz

    There is considerable interest in developing a power monitor system for Generation IV reactors (for instance GT-MHR). A new type of semiconductor radiation detector is under development based on silicon carbide (SiC) technology for these reactors. SiC has been selected as the semiconductor material due to its superior thermal-electrical-neutronic properties. Compared to Si, SiC is a radiation hard material; however, like Si, the properties of SiC are changed by irradiation by a large fluence of energetic neutrons, as a consequence of displacement damage, and that irradiation decreases the life-time of detectors. Predictions of displacement damage and the concomitant radiation effects are important for deciding where the SiC detectors should be placed. The purpose of this dissertation is to develop computer simulation methods to estimate the number of various defects created in SiC detectors, because of neutron irradiation, and predict at what positions of a reactor, SiC detectors could monitor the neutron flux with high reliability. The simulation modeling includes several well-known---and commercial---codes (MCNP5, TRIM, MARLOWE and VASP), and two kinetic Monte Carlo codes written by the author (MCASIC and DCRSIC). My dissertation will highlight the displacement damage that may happen in SiC detectors located in available positions in the OSURR, GT-MHR and IRIS. As extra modeling output data, the count rates of SiC for the specified locations are calculated. A conclusion of this thesis is SiC detectors that are placed in the thermal neutron region of a graphite moderator-reflector reactor have a chance to survive at least one reactor refueling cycle, while their count rates are acceptably high.

  4. High-resolution photoinduced transient spectroscopy of neutron irradiated bulk silicon

    CERN Document Server

    Kozlowski, R; Nossarzhevska, E

    2002-01-01

    High-resolution photoinduced transient spectroscopy has been employed in a study on the formation of defects in bulk silicon due to 1 MeV neutron irradiation. Apart from divacancies in various charge states, complexes involving interstitial carbon and oxygen were revealed. The defect structure of float zone and Czochralski-grown material exposed to fluences of 2x10 sup 1 sup 4 and 6.75x10 sup 1 sup 4 cm sup - sup 2 is compared.

  5. Results on photon and neutron irradiation of semitransparent amorphous-silicon sensors

    CERN Document Server

    Carabe, J; Ferrando, A; Fuentes, J; Gandia, J J; Josa-Mutuberria, I; Molinero, A; Oller, J C; Arce, P; Calvo, E; Figueroa, C F; García, N; Matorras, F; Rodrigo, T; Vila, I; Virto, A L; Fenyvesi, A; Molnár, J; Sohler, D

    2000-01-01

    Semitransparent amorphous-silicon sensors are basic elements for laser 2D position reconstruction in the CMS multipoint alignment link system. Some of the sensors have to work in a very hard radiation environment. Two different sensor types have been irradiated with /sup 60/Co photons (up to 100 kGy) and fast neutrons (up to 10/sup 15 / cm/sup -2/), and the subsequent change in their performance has been measured. (13 refs).

  6. Correlative Microscopy of Alpha Prime Precipitation in Neutron-Irradiated Fe-Cr-Al Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Briggs, Samuel A. [Univ. of Wisconsin, Madison, WI (United States)

    2016-12-01

    Fe-Cr-Al alloys are currently being considered for accident tolerant light water reactor fuel cladding applications due to their superior high temperature oxidation and corrosion resistance compared to Zr-based alloys. This work represents the current state-of-the-art on both techniques for analysis of α' precipitate microstructures and the processes and mechanisms governing its formation in neutron-irradiated Fe-Cr-Al alloys.

  7. Simulation of synergistic effects on lateral PNP bipolar transistors induced by neutron and gamma irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Chenhui, E-mail: wangchenhui@nint.ac.cn [State Key Laboratory of Intense Pulsed Irradiation Simulation and Effect, Northwest Institute of Nuclear Technology, P.O.Box 69-10, Xi' an 710024 (China); Bai, Xiaoyan; Chen, Wei; Yang, Shanchao; Liu, Yan; Jin, Xiaoming [State Key Laboratory of Intense Pulsed Irradiation Simulation and Effect, Northwest Institute of Nuclear Technology, P.O.Box 69-10, Xi' an 710024 (China); Ding, Lili [State Key Laboratory of Intense Pulsed Irradiation Simulation and Effect, Northwest Institute of Nuclear Technology, P.O.Box 69-10, Xi' an 710024 (China); Department of Information Engineering, Padova University, Via Gradenigo 6/B, 35131 Padova (Italy)

    2015-10-01

    With semiconductor device simulation software TCAD, numerical simulations of ionizing/displacement synergistic effects on 6 kinds of lateral PNP bipolar transistors induced by the mixed irradiation of neutron and gamma are carried out by means of changing the minority carrier lifetimes, adding charged traps to the oxide layer and increasing the surface recombination velocity in Si/SiO{sub 2} interface. The results indicate that ionizing/displacement synergistic effects on the lateral PNP bipolar transistors are not a simple sum of total ionizing dose effects and displacement effects, and total ionizing dose effects can enhance neutron displacement damages, leading to greater gain degradation. The physical mechanisms of ionizing/displacement synergistic effects are analyzed based on the results. The positive charge in the oxide layer and Si/SiO{sub 2} interface traps induced by gamma irradiation can enhance the recombination processes of carriers in the bulk defects induced by neutron irradiation, and this is the main cause of ionizing/displacement synergistic effects on the lateral PNP bipolar transistors. - Highlights: • Numerical simulation methods of ionizing/displacement synergistic effects induced by the mixed irradiation of neutron and gamma are established with semiconductor device simulation software TCAD. • Ionizing/displacement synergistic effects between the lateral PNP bipolar transistors with different neutral base widths and base doping concentrations are compared. • The difference between ionizing/displacement synergistic effects and the simple sum of total ionizing dose effects and displacement effects is analyzed. • The physical mechanisms of ionizing/displacement synergistic effects are explained.

  8. ATLAS MDT chamber behaviour after neutron irradiation and in a high rate background

    Energy Technology Data Exchange (ETDEWEB)

    Branchini, Paolo; Di Luise, Silvestro; Graziani, Enrico [Dipartimento di Fisica, Universita di Rome Tre and INFN Sezione di Roma Tre, Rome (Italy); Mazzotta, Concetta; Meoni, Evelin; Morello, Gianfranco [Dipartimento di Fisica, Universita della Calabria and INFN Gruppo Collegato di Cosenza, Cosenza (Italy); Passeri, Antonio; Petrucci, Fabrizio [Dipartimento di Fisica, Universita di Rome Tre and INFN Sezione di Roma Tre, Rome (Italy); Policicchio, Antonio [Dipartimento di Fisica, Universita della Calabria and INFN Gruppo Collegato di Cosenza, Cosenza (Italy)], E-mail: antonio.policicchio@cern.ch; Salvatore, Daniela; Schioppa, Marco [Dipartimento di Fisica, Universita della Calabria and INFN Gruppo Collegato di Cosenza, Cosenza (Italy)

    2007-10-21

    Many of the physics processes of interest at the Large Hadron Collider (LHC) will involve muon production in the final state. The Monitored Drift Tube (MDT) chambers, the precision tracking elements of the ATLAS muon spectrometer, are the main tools for the muon identification and measurement. They will operate in the harsh LHC background environment, mainly due to low energy photons and neutrons which will dominate the counting rate in most areas of the spectrometer, where an overall maximum counting rate of 500Hz/cm{sup 2} is expected. The upgrade to Super-LHC will involve fluxes ten times higher. To study the behaviour of MDT chambers under massive neutron irradiation at the level of Super-LHC, a test was performed at the 'Tapiro' Neutron Facility of the ENEA 'La Casaccia' Research Center.

  9. Study of boron carbide evolution under neutron irradiation; Contribution a l'etude de l'evolution du carbure de bore sous irradiation neutronique

    Energy Technology Data Exchange (ETDEWEB)

    Simeone, D. [CEA/Saclay, Dept. de Mecanique et de Technologie (DMT), 91 - Gif-sur-Yvette (France)]|[Universite Blaise Pascal, Clermont-Ferrand II, (CNRS), 63 - Aubiere (France)

    1999-07-01

    Owing to its high neutron efficiency, boron carbide (B{sub 4}C) is used as a neutron absorber in control rods of nuclear plants. Its behaviour under irradiation has been extensively studied for many years. It now seems clear that brittleness of the material induced by the {sup 10}B(n,{alpha}){sup 7}Li capture reaction is due to penny shaped helium bubbles associated to a high strain field around them. However, no model explains the behaviour of the material under neutron irradiation. In order to build such a model, this work uses different techniques: nuclear microprobe X-ray diffraction profile analysis and Raman and Nuclear Magnetic Resonance Spectroscopy to present an evolution model of B{sub 4}C under neutron irradiation. The use of nuclear reactions produced by a nuclear microprobe such as the {sup 7}Li(p,p'{gamma}){sup 7}Li reaction, allows to measure lithium profile in B{sub 4}C pellets irradiated either in Pressurised Water Reactors or in Fast Breeder Reactors. Examining such profiles enables us to describe the migration of lithium atoms out of B{sub 4}C materials under neutron irradiation. The analysis of X-ray diffraction profiles of irradiated B{sub 4}C samples allows us to quantify the concentrations of helium bubbles as well as the strain fields around such bubbles.Furthermore Raman spectroscopy studies of different B{sub 4}C samples lead us to propose that under neutron irradiation. the CBC linear chain disappears. Such a vanishing of this CBC chain. validated by NMR analysis, may explain the penny shaped of helium bubbles inside irradiated B{sub 4}C. (author)

  10. Effect and suppression of parasitic surface damage in neutron irradiated CMOS Monolithic Active Pixel Sensors

    CERN Document Server

    Deveaux, M; Scharrer, P; Stroth, J

    2016-01-01

    CMOS Monolithic Active Pixel Sensors (MAPS) were chosen as sensor technology for the vertex detectors of STAR, CBM and the upgraded ALICE-ITS. They also constitute a valuable option for tracking devices at future e+e- colliders. Those applications require a substantial tolerance to both, ionizing and non-ionizing radiation. To allow for a focused optimization of the radiation tolerance, prototypes are tested by irradiating the devices either with purely ionizing radiation (e.g. soft X-rays) or the most pure sources of non-ionizing radiation available (e.g. reactor neutrons). In the second case, it is typically assumed that the impact of the parasitic $\\gamma$-rays found in the neutron beams is negligible. We checked this assumption by irradiating MAPS with $\\gamma$-rays and comparing the radiation damage generated with the one in neutron irradiated sensors. We conclude that the parasitic radiation doses may cause non-negligible radiation damage. Based on the results we propose a procedure to recognize and to ...

  11. The effects of fast neutron irradiation on oxygen in Czochralski silicon

    Institute of Scientific and Technical Information of China (English)

    Chen Gui-Feng; Yan Wen-Bo; Chen Hong-Jian; Li Xing-Hua; Li Yang-Xian

    2009-01-01

    The effects of fast neutron irradiation on oxygen atoms in Czochralski silicon (CZ-Si) are investigated systemically by using Fourier transform infrared (FTIR) spectrometer and positron annihilation technique (PAT). Through isochronal annealing, it is found that the trend of variation in interstitial oxygen concentration ([Oi]) in fast neutrons irradiated CZ-Si fluctuates largely with temperature increasing, especially between 500 and 700℃. After the CZ-Si is annealed at 600℃, the V4 appearing as three-dimensional vacancy clusters causes the formation of the molecule-like oxygen clusters, and more importantly these dimers with small binding energies (0.1-1.0eV) can diffuse into the Si lattices more easily than single oxygen atoms, thereby leading to the strong oxygen agglomerations. When the CZ-Si is annealed at temperature increasing up to 700℃, three-dimensional vacancy clusters disappear and the oxygen agglomerations decompose into single oxygen atoms (O) at interstitial sites. Results from FTIR spectrometer and PAT provide an insight into the nature of the [Oi] at temperatures between 500 and 700℃. It turns out that the large fluctuation of [Oi] after short-time annealing from 500 to 700℃ results from the transformation of fast neutron irradiation defects.

  12. Severe immune dysfunction after lethal neutron irradiation in a JCO nuclear facility accident victim.

    Science.gov (United States)

    Nagayama, Hitomi; Ooi, Jun; Tomonari, Akira; Iseki, Tohru; Tojo, Arinobu; Tani, Kenzaburo; Takahashi, Tsuneo A; Yamashita, Naohide; Shigetaka, Asano

    2002-08-01

    The optimal treatment for the hematological toxicity of acute radiation syndrome (ARS) is not fully established, especially in cases of high-dose nonuniform irradiation by mixed neutrons and gamma-rays, because estimation of the irradiation dose (dosimetry) and prediction of autologous hematological recovery are complicated. For the treatment of ARS, we performed HLA-DRB1-mismatched unrelated umbilical cord blood transplantation (CBT) for a nuclear accident victim who received 8 to 10 GyEq mixed neutron and gamma-ray irradiation at the JCO Co. Ltd. nuclear processing facility in Tokaimura, Japan. Donor/ recipient mixed chimerism was attained; thereafter rapid autologous hematopoietic recovery was achieved in concordance with the termination of immunosuppressants. Immune function examined in vitro showed recovery of the autologous immune system was severely impaired. Although the naive T-cell fraction and the helper T-cell subtype 1 fraction were increased, the mitogenic responses of T-cells and the allogeneic mixed leukocyte reaction were severely suppressed. Endogenous immunoglobulin production was also suppressed until 120 days after the accident. Although skin transplantation for ARS was successful, the patient died of infectious complications and subsequent acute respiratory distress syndrome 210 days after the accident. These results suggest that fast neutrons in doses higher than 8 to 10 Gy cause complete abrogation of the human immune system, which may lead to fatal outcome even if autologous hematopoiesis recovers. The roles of transplantation, autologous hematopoietic recovery, chimerism, immune suppression, and immune function are discussed.

  13. The effect of neutron irradiation on oxygen aggregation processes in Si material treated under hydrostatic pressure

    Energy Technology Data Exchange (ETDEWEB)

    Londos, Charalampos A.; Andrianakis, Andreas [Solid State Section, Physics Department, University of Athens, Panepistimiopolis, Zografos, 157 84 Athens (Greece); Misiuk, Andrzej [Institute of Electron Technology, Al. Lotnikow 46, 02-668 Warsaw (Poland)

    2011-03-15

    Silicon is the dominant material in electronic industry. Its use for various applications requires processing stages, important among them those involving thermal treatments. Such treatments in Si trigger the mechanisms of oxygen aggregation resulting in the formation of oxygen precipitates which have important influence on the quality of the material. In the present work, we have investigated the effect of thermal treatments, with or without the application of high hydrostatic pressure, on the development of oxygen precipitates. We have particularly studied the effect of neutron irradiation on the formation of the various oxygen agglomerates in the course of the above treatments. To this end, Si samples initially irradiated by neutrons were subjected to high temperature or/and high temperature-high pressure treatments at 1000 and 1130 C. Afterwards, infrared (IR) measurements were undertaken to study various precipitate morphologies, in particular those giving rise to an IR band around 1080 cm{sup -1} related to octahedral-shaped precipitates and an IR band at 1225 cm{sup -1} attributed to platelet-shaped precipitates. The obtained results were found to be consistent with reports cited in the literature. It was confirmed that the application of pressure during treatments as well as the irradiation with neutrons before these treatments enhance substantially the oxygen aggregation process. Comparisons of the results between treatments at 1000 and 1130 C are presented and discussed. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  14. Thermoluminescence response of sodalime glass irradiated with proton and neutron beams

    Energy Technology Data Exchange (ETDEWEB)

    Marrale, M. [Dipartimento di Fisica, Universita degli Studi di Palermo, Viale delle Scienze, Edificio 18, 90128 Palermo (Italy); INFN Gruppo V, Via Santa Sofia 64, 95123 Catania (Italy); Longo, A., E-mail: anna.longo@unipa.it [Dipartimento di Fisica, Universita degli Studi di Palermo, Viale delle Scienze, Edificio 18, 90128 Palermo (Italy); INFN Gruppo V, Via Santa Sofia 64, 95123 Catania (Italy); Bartolotta, A. [Dipartimento STEMBIO, Via delle Scienze, Ed. 16, 90128 Palermo (Italy); Basile, S. [Dipartimento di Fisica, Universita degli Studi di Palermo, Viale delle Scienze, Edificio 18, 90128 Palermo (Italy); INFN Gruppo V, Via Santa Sofia 64, 95123 Catania (Italy); D' Oca, M.C. [Dipartimento STEMBIO, Via delle Scienze, Ed. 16, 90128 Palermo (Italy); Tomarchio, E. [Dipartimento dell' Energia, Universita degli Studi di Palermo, Viale delle Scienze, Edificio 6, 90128 Palermo (Italy); Cirrone, G.A.P. [Laboratori Nazionali del Sud INFN, Via Santa Sofia 65, 95123 Catania (Italy); Di Rosa, F. [Azienda Sanitaria Provinciale N 2, Pres. Osped. ' M. Raimondi' , Via Forlanini 5, S. Cataldo (Italy); Romano, F. [Laboratori Nazionali del Sud INFN, Via Santa Sofia 65, 95123 Catania (Italy); Museo Storico della Fisica e Centro Studi e Ricerche ' E. Fermi' Compendio del Viminale, Piazza del Viminale 1, 00184 Roma (Italy); Cuttone, G. [Laboratori Nazionali del Sud INFN, Via Santa Sofia 65, 95123 Catania (Italy); Brai, M. [Dipartimento di Fisica, Universita degli Studi di Palermo, Viale delle Scienze, Edificio 18, 90128 Palermo (Italy); INFN Gruppo V, Via Santa Sofia 64, 95123 Catania (Italy)

    2012-12-01

    In the research field of emergency dosimeters to be used in case of accidental radiation exposure of the population, watch glass has been considered as a possible fortuitous dosimetric material. This paper reports on results obtained by thermoluminescence of glass samples exposed to neutron and proton beams. Thermoluminescent glow curves have been analyzed for each irradiation studying the modifications induced by the irradiation as a function of proton dose or neutron fluence. The glow curve in a specific temperature range has been used as dosimetric parameter. The thermoluminescence response of samples exposed to protons has been found to be linear in the dose range between 2 and 20 Gy and the lowest detectable dose for this radiation beam is estimated to be smaller than than 1 Gy. In case of exposure with thermal neutrons the TL signal linearly increases with neutron fluence (up to about 3 Multiplication-Sign 10{sup 11} cm{sup -2}) and the lowest detectable fluence has been found to be of the order of magnitude of 10{sup 9} cm{sup -2}. These results could be of interest for accidental retrospective dosimetry.

  15. Proton and Neutron Irradiation Tests of Readout Electronics of the ATLAS Hadronic Endcap Calorimeter

    CERN Document Server

    INSPIRE-00106910

    2012-01-01

    The readout electronics of the ATLAS Hadronic Endcap Calorimeter will have to withstand the about ten times larger radiation environment of the future high-luminosity LHC (HL-LHC) compared to their design values. The GaAs ASIC which comprises the heart of the readout electronics has been exposed to neutron and proton radiation with fluences up to ten times the total expected fluences for ten years of running of the HL-LHC. Neutron tests were performed at the NPI in Rez, Czech Republic, where a 36 MeV proton beam is directed on a thick heavy water target to produce neutrons. The proton irradiation was done with 200 MeV protons at the PROSCAN area of the Proton Irradiation Facility at the PSI in Villigen, Switzerland. In-situ measurements of S-parameters in both tests allow the evaluation of frequency dependent performance parameters - like gain and input impedance - as a function of the fluence. The linearity of the ASIC response has been measured directly in the neutron tests with a triangular input pulse of ...

  16. Proton and Neutron Irradiation Tests of Readout Electronics of the ATLAS Hadronic Endcap Calorimeter

    CERN Document Server

    Menke, Sven; The ATLAS collaboration

    2012-01-01

    The readout electronics of the ATLAS Hadronic Endcap Calorimeter will have to withstand the about ten times larger radiation environment of the future high-luminosity LHC (HL-LHC) compared to their design values. The GaAs ASIC which comprises the heart of the readout electronics has been exposed to neutron and proton radiation with fluences up to ten times the total expected fluences for ten years of running of the HL-LHC. Neutron tests where performed at the NPI in Rez, Czech Republic, where a 36 MeV proton beam is directed on a thick heavy water target to produce neutrons. The proton irradiation was done with 200 MeV protons at the PROSCAN area of the Proton Irradiation Facility at the PSI in Villigen, Switzerland. In-situ measurements of S-parameters in both tests allow the evaluation of frequency dependent performance parameters - like gain and input impedance - as a function of the fluence. The linearity of the ASIC response has been measured directly in the neutron tests with a triangular input pulse of...

  17. Feasibility study of photo-neutron flux in various irradiation channels of Ghana MNSR using a Monte Carlo code

    Energy Technology Data Exchange (ETDEWEB)

    Birikorang, S.A., E-mail: anddydat@yahoo.com [Department of Nuclear Engineering and Material Science, School of Nuclear and Allied Sciences (SNAS), University of Ghana, P.O. Box AE 1, Atomic Energy, Accra (Ghana); Akaho, E.H.K.; Nyarko, B.J.B. [National Nuclear Research Institute, Ghana Atomic Energy Commission, P.O. Box LG 80, Legon, Accra-Ghana (Ghana); Ampomah-Amoako, E.; Seth, Debrah K.; Gyabour, R.A.; Sogbgaji, R.B.M. [Department of Nuclear Engineering and Material Science, School of Nuclear and Allied Sciences (SNAS), University of Ghana, P.O. Box AE 1, Atomic Energy, Accra (Ghana)

    2011-07-15

    Highlights: > The photo-neutron source was investigated within Ghana MNSR irradiation channels. > Irradiation channels under study were inner, outer and the fission chamber. > Thermal rated power at sub-critical state was estimated. > Neutron flux variation was investigated within the channels. > MCNP code has been used to investigate the flux variation. - Abstract: Computer simulation was carried out for photo-neutron source variation in outer irradiation channel, inner irradiation channels and the fission channel of a tank-in-pool reactor, a Miniature Neutron Source Reactor (MNSR) in sub-critical condition. Evaluation of the photo-neutron was done after the reactor has been in sub-critical condition for three month period using Monte Carlo Neutron Particle (MCNP) code. Neutron flux monitoring from the Micro Computer Control Loop System (MCCLS) was also investigated at sub-critical condition. The recorded neutron fluxes from the MCCLS after investigations were used to calculate the power of the reactor at sub-critical state. The computed power at sub-critical state was used to normalize the un-normalized results from the MCNP.

  18. Tritium Retention and Permeation in Ion- and Neutron-Irradiated Tungsten under US-Japan PHENIX Collaboration

    Science.gov (United States)

    Shimada, Masashi; Taylor, Chase N.; Kolasinski, Robert D.; Buchenauer, Dean A.; Chikada, Takumi; Oya, Yasuhisa; Hatano, Yuji

    2015-11-01

    A critical challenge for long-term operation of ITER and beyond to a FNSF, a DEMO and future fusion reactor will be the development of plasma-facing components (PFCs) that demonstrate erosion resistance to intense heat and neutral/ion particle fluxes under the extreme fusion nuclear environment, while minimizing in-vessel inventories and ex-vessel permeation of tritium. Recent work at Tritium Plasma Experiment demonstrated that tritium diffuses in bulk tungsten at elevated temperatures, and can be trapped in radiation-induced trap site (up to 1 at. % T/W) in tungsten [M. Shimada, et.al., Nucl. Fusion 55 (2015) 013008]. US-Japan PHENIX collaboration (2013-2019) investigates irradiation response on tritium behavior in tungsten, and performs one-of-a-kind neutron-irradiation with Gd thermal neutron shield at High Flux Isotope Reactor, ORNL. This presentation describes the challenge in elucidating tritium behavior in neutron-irradiated PFCs, the PHENIX plans for neutron-irradiation and post irradiation examination, and the recent findings on tritium retention and permeation in 14MeV neutron-irradiated and Fe ion irradiated tungsten. This work was prepared for the U.S. Department of Energy, Office of Fusion Energy Sciences, under the DOE Idaho Field Office contract number DE-AC07-05ID14517.

  19. Development and characteristics of the HANARO ex-core neutron irradiation facility for applications in the boron neutron capture therapy field

    CERN Document Server

    Kim, M S; Jun, B J; Kim, H; Lee, B C; Hwang, Sung-Yul; Jun, Byung-Jin; Kim, Heonil; Kim, Myong-Seop; Lee, Byung-Chul

    2006-01-01

    The HANARO ex-core neutron irradiation facility was developed for various applications in the boron neutron capture therapy (BNCT) field, and its characteristics have been investigated. In order to obtain a sufficient thermal neutron flux with a low level contamination of fast neutrons and gamma-rays, a radiation filtering method is adopted. The radiation filter has been designed by using a silicon single crystal cooled by liquid nitrogen and a bismuth crystal. The installation of the main components of the irradiation facility and the irradiation room are finished. Experimental measurements of the neutron beam characteristics have been performed by using bare and cadmium covered gold foils and wires. The in-phantom neutron flux distribution was measured for a flux mapping inside the phantom. The gamma-ray dose was determined by using TLD-700 thermoluminescence dosimeters. The thermal and fast neutron fluxes and the gamma-ray dose were calculated by using the MCNP code, and they were compared with experimenta...

  20. Hot deuteron generation and neutron production in deuterated nanowire array irradiated at relativistic intensity

    Science.gov (United States)

    Curtis, Alden; Calvi, Chase; Tinsley, Jim; Hollinger, Reed; Wang, Shoujun; Rockwood, Alex; Wang, Yong; Buss, Conrad; Shlyaptsev, Vyacheslav; Kaymak, V.; Pukhov, Alexander; Rocca, Jorge

    2016-10-01

    Irradiation of arrays of aligned high aspect ratio nanowires with high contrast femtosecond laser pulses of relativistic intensity was recently shown to volumetrically heat near solid density plasmas to multi-KeV energy. Using aligned arrays of deuterated polyethylene nanowires (CD2) irradiated at laser intensities of up to 1 ×1020 W/cm2 we are able to generate near solid density plasmas in which the tail of the deuteron distribution was measured to reach energies of up to 3 MeV, in agreement with particle-in-cell simulations. Comparative measurements conducted using flat CD2 targets irradiated by the same laser pulses show the maximum deuteron energies are sub-MeV. We also observed a 100x increase in the number of neutrons produced as compared to flat CD2 targets irradiated at the same conditions, with the highest yield shots producing above 106 neutrons per Joule of laser energy. Work supported by AFOSR Award FA9560-14-10232 and NSTec SDRD program.

  1. Effect of periodic temperature variations on the microstructure of neutron-irradiated metals

    DEFF Research Database (Denmark)

    Zinkle, S.J.; Hashimoto, N.; Hoelzer, D.T.

    2002-01-01

    Specimens of pure copper, a high purity austenitic stainless steel, and V–4Cr–4Ti were exposed to eight cycles of either constant temperature or periodic temperature variations during neutron irradiation in the High Flux Isotopes Reactor to a cumulative damage level of 4–5 displacements per atom.......-induced microstructural features consisted of dislocation loops, stacking fault tetrahedra and voids in the stainless steel, Ti-rich precipitates in the V alloy, and voids (along with a low density of stacking fault tetrahedra) in copper.......Specimens of pure copper, a high purity austenitic stainless steel, and V–4Cr–4Ti were exposed to eight cycles of either constant temperature or periodic temperature variations during neutron irradiation in the High Flux Isotopes Reactor to a cumulative damage level of 4–5 displacements per atom...... and V–4Cr–4Ti were qualitatively similar to companion specimens that were continuously maintained at 520 °C during the entire irradiation. The microstructural observations on pure copper irradiated at a constant temperature of 340 °C in this experiment are also summarized. The main radiation...

  2. Radiation damage to neutron and proton irradiated GaAs particle detectors

    CERN Document Server

    Rogalla, M; Evans, N; Joost, S; Kienzle-Focacci, M N; Geppert, R; Göppert, R; Irsigler, R; Ludwig, J; Runge, K; Schmid, T; Eich, Th.; Schmid, Th.

    1997-01-01

    The radiation damage in 200 um thick Schottky diodes made on semi-insulating (SI) undoped GaAs Liquid Encapsulated Czochralski (LEC) bulk material with resistivities between 0.4 and 8.9*10E7 Ohm*cm were studied using alpha-spectroscopy, signal response to minimum ionising particles (MIP), I-V and CV-measurements. The results have been analysed to investigate the influence of the substrate resistivity on the detector performance after neutron and proton irradiation. The leakage current density, signal response to alpha-particles and MIPs show a strong dependence on the resistivity before and after irradiation. An observed decrease of the electron mean free drift length before and after irradiation with increasing substrate resistivity can be explained by a model involving the different ionisation ratios of defects, which are introduced by the irradiation. Comparison of the radiation damage due to neutrons and protons gives a hardness factor of 7+-0.9 for 24 GeV/c protons. The best detectors show a response to ...

  3. Image processing analysis of nuclear track parameters for CR-39 detector irradiated by thermal neutron

    Science.gov (United States)

    Al-Jobouri, Hussain A.; Rajab, Mustafa Y.

    2016-03-01

    CR-39 detector which covered with boric acid (H3Bo3) pellet was irradiated by thermal neutrons from (241Am - 9Be) source with activity 12Ci and neutron flux 105 n. cm-2. s-1. The irradiation times -TD for detector were 4h, 8h, 16h and 24h. Chemical etching solution for detector was sodium hydroxide NaOH, 6.25N with 45 min etching time and 60 C˚ temperature. Images of CR-39 detector after chemical etching were taken from digital camera which connected from optical microscope. MATLAB software version 7.0 was used to image processing. The outputs of image processing of MATLAB software were analyzed and found the following relationships: (a) The irradiation time -TD has behavior linear relationships with following nuclear track parameters: i) total track number - NT ii) maximum track number - MRD (relative to track diameter - DT) at response region range 2.5 µm to 4 µm iii) maximum track number - MD (without depending on track diameter - DT). (b) The irradiation time -TD has behavior logarithmic relationship with maximum track number - MA (without depending on track area - AT). The image processing technique principally track diameter - DT can be take into account to classification of α-particle emitters, In addition to the contribution of these technique in preparation of nano- filters and nano-membrane in nanotechnology fields.

  4. Defect annealing and thermal desorption of deuterium in low dose HFIR neutron-irradiated tungsten

    Energy Technology Data Exchange (ETDEWEB)

    Masashi Shimada; M. Hara; T. Otsuka; Y. Oya; Y. Hatano

    2014-05-01

    Accurately estimating tritium retention in plasma facing components (PFCs) and minimizing its uncertainty are key safety issues for licensing future fusion power reactors. D-T fusion reactions produce 14.1 MeV neutrons that activate PFCs and create radiation defects throughout the bulk of the material of these components. Recent studies show that tritium migrates and is trapped in bulk (>> 10 µm) tungsten beyond the detection range of nuclear reaction analysis technique [1-2], and thermal desorption spectroscopy (TDS) technique becomes the only established diagnostic that can reveal hydrogen isotope behavior in in bulk (>> 10 µm) tungsten. Radiation damage and its recovery mechanisms in neutron-irradiated tungsten are still poorly understood, and neutron-irradiation data of tungsten is very limited. In this paper, systematic investigations with repeated plasma exposures and thermal desorption are performed to study defect annealing and thermal desorption of deuterium in low dose neutron-irradiated tungsten. Three tungsten samples (99.99 at. % purity from A.L.M.T. Co., Japan) irradiated at High Flux Isotope Reactor at Oak Ridge National Laboratory were exposed to high flux (ion flux of (0.5-1.0)x1022 m-2s-1 and ion fluence of 1x1026 m-2) deuterium plasma at three different temperatures (100, 200, and 500 °C) in Tritium Plasma Experiment at Idaho National Laboratory. Subsequently, thermal desorption spectroscopy (TDS) was performed with a ramp rate of 10 °C/min up to 900 °C, and the samples were annealed at 900 °C for 0.5 hour. These procedures were repeated three (for 100 and 200 °C samples) and four (for 500 °C sample) times to uncover damage recovery mechanisms and its effects on deuterium behavior. The results show that deuterium retention decreases approximately 90, 75, and 66 % for 100, 200, and 500 °C, respectively after each annealing. When subjected to the same TDS recipe, the desorption temperature shifts from 800 °C to 600 °C after 1st annealing

  5. Spectroscopy of Low Temperature Plasma

    CERN Document Server

    Ochkin, Vladimir N

    2009-01-01

    Providing an up-to-date overview on spectroscopical diagnostics of low temperature plasma Spectroscopy of Low Temperature Plasma covers the latest developments and techniques. Written by a distinguished scientist and experienced book author this text is applicable to many fields in materials and surface science as well as nanotechnology and contains numerous appendices with indispensable reference data.

  6. Embrittlement behaviour of different international low activation alloys after neutron irradiation

    Science.gov (United States)

    Schneider, H.-C.; Dafferner, B.; Aktaa, J.

    2001-05-01

    The embrittlement behaviour of ferritic/martensitic steels after irradiation in the Petten high flux reactor (HFR) was investigated by instrumented Charpy-V tests with subsize specimens. The main objective, apart from studying effects of particularly low doses, was a comparison of low activation alloys (LAA) from various countries with different Cr contents and different types and concentrations of minor alloying elements and impurities. In the present report, the results of another three materials (OPTIMAR, OPTIFER-IV, GA3X) obtained within the second phase of the MANITU programme (0.8 dpa, at 250-450°C) were analysed and assessed in comparison to the results of the first irradiation up to 0.8 dpa. The evaluation clearly showed a reduced embrittlement problem for the advanced reduced-activation alloys. Of the examined alloys, the GA3X steel shows the very best embrittlement behaviour after neutron irradiation.

  7. PGNAA system preliminary design and measurement of In-Hospital Neutron Irradiator for boron concentration measurement.

    Science.gov (United States)

    Zhang, Zizhu; Chong, Yizheng; Chen, Xinru; Jin, Congjun; Yang, Lijun; Liu, Tong

    2015-12-01

    A prompt gamma neutron activation analysis (PGNAA) system has been recently developed at the 30-kW research reactor In-Hospital Neutron Irradiator (IHNI) in Beijing. Neutrons from the specially designed thermal neutron beam were used. The thermal flux of this beam is 3.08×10(6) cm(-2) s(-1) at a full reactor power of 30 kW. The PGNAA system consists of an n-type high-purity germanium (HPGe) detector of 40% efficiency, a digital spectrometer, and a shielding part. For both the detector shielding part and the neutron beam shielding part, the inner layer is composed of (6)Li2CO3 powder and the outer layer lead. The boron-10 sensitivity of the PGNAA system is approximately 2.5 cps/ppm. Two calibration curves were produced for the 1-10 ppm and 10-50 ppm samples. The measurement results of the control samples were in accordance with the inductively coupled plasma atomic emission spectroscopy (ICP-AES) results.

  8. High Temperature Tensile Properties of Unirradiated and Neutron Irradiated 20 Cr-35 Ni Austenitic Steel

    Energy Technology Data Exchange (ETDEWEB)

    Roy, R.B.; Solly, B.

    1966-12-15

    The tensile properties of an unirradiated and neutron irradiated (at 40 deg C) 20 % Cr, 35 % Ni austenitic steel have been studied at 650 deg C, 750 deg C and 820 deg C. The tensile elongation and mode of fracture (transgranular) of unirradiated specimens tested at room temperature and 650 deg C are almost identical. At 750 deg C and 820 deg C the elongation decreases considerably and a large part of the total elongation is non-uniform. Furthermore, the mode of fracture at these temperatures is intergranular and microscopic evidence suggests that fracture is caused by formation and linkup of grain boundary cavities. YS and UTS decrease monotonically with temperature. Irradiated specimens show a further decrease in ductility and an increase in the tendency to grain boundary cracking. Irradiation has no significant effect on the YS, but the UTS are reduced. The embrittlement of the irradiated specimens is attributed to the presence of He and Li atoms produced during irradiation and the possible mechanisms are discussed. Prolonged annealing of irradiated and unirradiated specimens at 650 deg C appears to have no significant effect on tensile properties.

  9. Nano-cluster stability following neutron irradiation in MA957 oxide dispersion strengthened material

    Energy Technology Data Exchange (ETDEWEB)

    Ribis, J., E-mail: joel.ribis@cea.fr [CEA, DEN, DMN, SRMA, F-91191 Gif sur Yvette (France); Lozano-Perez, S. [Department of Materials, University of Oxford, Parks Road, OX1 3PH Oxford (United Kingdom)

    2014-01-15

    ODS steels are promising materials for Sodium cooled Fast Reactors since their fine distribution of nano-clusters confers excellent mechanical properties. However, the nano-feature stability needs to be assessed under neutron irradiation. Before irradiation, the characterizations show that nano-particles are finely distributed within the ferritic matrix and are identified to have a pyrochlore type structure. After irradiation of the MA957 alloy in the Phenix French reactor at 412 °C up to 50 dpa and 430 °C up to 75 dpa, transmission electron microscopy characterization reveals a very slight density fall but no distinguishable difference in nano-features size before and after irradiation. In addition, after both irradiations, the nano-oxides are still (Y, Ti, O) compounds with orientation relationship with the matrix. A multislice simulation of high resolution images suggests that nano-particles still have a fcc pyrochlore type structure after irradiation. A possible change of lattice parameter seems to be highlighted, possibly due to disordering by cascade effect.

  10. Irradiation creep of nano-powder sintered silicon carbide at low neutron fluences

    Science.gov (United States)

    Koyanagi, T.; Shimoda, K.; Kondo, S.; Hinoki, T.; Ozawa, K.; Katoh, Y.

    2014-12-01

    The irradiation creep behavior of nano-powder sintered silicon carbide was investigated using the bend stress relaxation method under neutron irradiation up to 1.9 dpa. The creep deformation was observed at all temperatures ranging from 380 to 1180 °C mainly from the irradiation creep but with the increasing contributions from the thermal creep at higher temperatures. The apparent stress exponent of the irradiation creep slightly exceeded unity, and instantaneous creep coefficient at 380-790 °C was estimated to be ∼1 × 10-5 [MPa-1 dpa-1] at ∼0.1 dpa and 1 × 10-7 to 1 × 10-6 [MPa-1 dpa-1] at ∼1 dpa. The irradiation creep strain appeared greater than that for the high purity SiC. Microstructural observation and data analysis indicated that the grain-boundary sliding associated with the secondary phases contributes to the irradiation creep at 380-790 °C to 0.01-0.11 dpa.

  11. Nano-cluster stability following neutron irradiation in MA957 oxide dispersion strengthened material

    Science.gov (United States)

    Ribis, J.; Lozano-Perez, S.

    2014-01-01

    ODS steels are promising materials for Sodium cooled Fast Reactors since their fine distribution of nano-clusters confers excellent mechanical properties. However, the nano-feature stability needs to be assessed under neutron irradiation. Before irradiation, the characterizations show that nano-particles are finely distributed within the ferritic matrix and are identified to have a pyrochlore type structure. After irradiation of the MA957 alloy in the Phenix French reactor at 412 °C up to 50 dpa and 430 °C up to 75 dpa, transmission electron microscopy characterization reveals a very slight density fall but no distinguishable difference in nano-features size before and after irradiation. In addition, after both irradiations, the nano-oxides are still (Y, Ti, O) compounds with orientation relationship with the matrix. A multislice simulation of high resolution images suggests that nano-particles still have a fcc pyrochlore type structure after irradiation. A possible change of lattice parameter seems to be highlighted, possibly due to disordering by cascade effect.

  12. Neutron-irradiation creep of silicon carbide materials beyond the initial transient

    Science.gov (United States)

    Koyanagi, Takaaki; Katoh, Yutai; Ozawa, Kazumi; Shimoda, Kazuya; Hinoki, Tatsuya; Snead, Lance L.

    2016-09-01

    Irradiation creep beyond the transient regime was investigated for various silicon carbide (SiC) materials. The materials examined included polycrystalline or monocrystalline high-purity SiC, nanopowder sintered SiC, highly crystalline and near-stoichiometric SiC fibers (including Hi-Nicalon Type S, Tyranno SA3, isotopically-controlled Sylramic and Sylramic-iBN fibers), and a Tyranno SA3 fiber-reinforced SiC matrix composite fabricated through a nano-infiltration transient eutectic phase process. Neutron irradiation experiments for bend stress relaxation tests were conducted at irradiation temperatures ranging from 430 to 1180 °C up to 30 dpa with initial bend stresses of up to ∼1 GPa for the fibers and ∼300 MPa for the other materials. Initial bend stress in the specimens continued to decrease from 1 to 30 dpa. Analysis revealed that (1) the stress exponent of irradiation creep above 1 dpa is approximately unity, (2) the stress normalized creep rate is ∼1 × 10-7 [dpa-1 MPa-1] at 430-750 °C for the range of 1-30 dpa for most polycrystalline SiC materials, and (3) the effects on irradiation creep of initial microstructures-such as grain boundary, crystal orientation, and secondary phases-increase with increasing irradiation temperature.

  13. Influence of temperature on the behaviour of INTEGRAL n-type HPGe detectors irradiated with fast neutrons

    CERN Document Server

    Kandel, B; Albernhe, F; Frabel, P; Cordier, B; Tauzin, G; Crespin, S; Coszach, R; Denis, J M; Leleux, P

    1999-01-01

    Several INTEGRAL n-type HPGe detectors have been irradiated by fast neutrons at different temperatures and their performances have been evaluated. Their behaviour during warm-up and cool-down cycles following the irradiations show evidence for irreversible temperature effects above 100 K. The detectors recovery after annealing was also studied.

  14. The influence of low dose neutron irradiation on the thermal conductivity of Allcomp carbon foam

    Energy Technology Data Exchange (ETDEWEB)

    Burchell, Timothy D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Porter, Wallace D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); McDuffee, Joel Lee [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-03-01

    Oak Ridge National Laboratory was contracted via a Work for Others Agreement with Allcomp Inc. (NFE-14-05011-MSOF: Carbon Foam for Beam Stop Applications ) to determine the influence of low irradiation dose on the thermal conductivity of Allcomp Carbon Foam. Samples (6 mm dia. x 5 mm thick) were successfully irradiated in a rabbit capsule in a hydraulic tube in the target region of the High Flux Isotope Reactor at the Oak Ridge National Laboratory. The specimens were irradiated at Tirr = 747.5 C to a neutron damage dose of 0.2 dpa. There is a small dimensional and volume shrinkage and the mass and density appear reduced (we would expect density to increase as volume reduces at constant mass). The small changes in density, dimensions or volume are not of concern. At 0.2 dpa the irradiation shrinkage rate difference between the glassy carbon skeleton and the CVD coating was not sufficient to cause a large enough irradiation-induced strain to create any mechanical degradation. Similarly differential thermal expansion was not a problem. It appears that only the thermal conductivity was affected by 0.2 dpa. For the intended application conditions, i.e. @ 400 C and 0 DPA (start- up) the foam thermal conductivity is about 57 W/m.K and at 700 C and 0.2 DPA (end of life) the foam thermal conductivity is approx. 30.7 W/m.K. The room temp thermal conductivity drops from 100-120 W/m.K to approximately 30 W/m.K after 0.2 dpa of neutron irradiation.

  15. Comparison of properties and microstructures of Trefimetaux and Hycon 3HP{trademark} after neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, D.J. [Pacific Northwest National Lab., Richland, WA (United States); Singh, B.N.; Toft, P.; Eldrup, M. [Risoe National Lab., Roskilde (Denmark)

    1998-09-01

    The precipitation strengthened CuNiBe alloys are among three candidate copper alloys being evaluated for application in the first wall, divertor, and limiter components of ITER. Generally, CuNiBe alloys have higher strength but poorer conductivity compared to CuCrZr and CuAl{sub 2}O{sub 3} alloys. Brush-Wellman Inc. has manufactured an improved version of their Hycon CuNiBe alloy that has higher conductivity while maintaining a reasonable level strength. It is of interest, therefore, to investigate the effect of radiation on the physical and mechanical properties of this alloy. In the present work the authors have investigated the physical and mechanical properties of the Hycon 3HP{trademark} alloy both before and after neutron irradiation and have compared its microstructure and properties with the European CuNiBe candidate alloy manufactured by Trefirmetaux. Tensile specimens of both alloys were irradiated in the DR-3 reactor at Risoe to displacement dose levels up to 0.3 dpa at 100, 250 and 350 C. Both alloys were tensile tested in the unirradiated and irradiated conditions at 100, 250 and 350 C. Both pre- and post-irradiation microstructures of the alloys were investigated in detail using transmission electron microscopy. Fracture surfaces were examined under a scanning electron microscope. Electrical resistivity measurements were made on tensile specimens before and after irradiation; all measurements were made at 23 C. At this point it seems unlikely that CuNiBe alloys can be recommended for applications in neutron environments where the irradiation temperature exceeds 200 C. Applications at temperatures below 200 C might be plausible, but only after careful experiments have determined the dose dependence of the mechanical properties and the effect of sudden temperature excursions on the material to establish the limits on the use of the alloy.

  16. Emission properties of InGaAs/GaAs heterostructures with quantum wells and dots after irradiation with neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Baidus, N. V.; Vikhrova, O. V., E-mail: vikhrova@nifti.unn.ru; Zvonkov, B. N.; Malysheva, E. I. [Lobachevsky State University of Nizhni Novgorod, Physical-Technical Research Institute (Russian Federation); Trufanov, A. N. [Sedakov Research Institute of Measurement Systems, GSP-486 (Russian Federation)

    2015-03-15

    The effect of neutron radiation on the luminescence of InGaAs/GaAs heterostructures with quantum wells and quantum dots is studied. It is found that neutron radiation results both in the formation of defects and in the radiation-induced annealing of growth-related defects. Quantum dots are more stable to neutron radiation in comparison with quantum wells. It is shown that the layer of InGaAs/GaAs quantum dots located near the surface is less sensitive to irradiation with neutrons compared with a similar layer located in the bulk. In the first case, one can observe an increase in the photoluminescence and electroluminescence intensities after irradiation with neutrons, which is related to the effects of radiation-induced annealing. The pronounced effect of elastic strains in the InGaAs/GaAs quantum wells on the extent of quenching of the photoluminescence intensity upon irradiation with neutrons is revealed. In heterostructures with quantum wells, the effect of radiation-induced annealing manifests itself in a shift of the photoluminescence peak to longer wavelengths as a result of a decrease in elastic strains upon irradiation with neutrons. Doping of the GaAs buffer layer with silicon also reduces the value of this spectral shift.

  17. [Split-course neutron and photon irradiation of experimental tumors: the importance of the sequence and interval lengths].

    Science.gov (United States)

    Carl, U M; Bahnsen, J

    1989-09-01

    In a split course mixed beam experiment we have investigated the influence of the interval and beam-quality on tumour growth delay. Fast growing sarcomas (SaF) in grey CBA-mice were irradiated with different sequences of neutrons (N) and photons (X) varying the length of time interval from 0 up to 300 minutes between two doses. The tumours were treated with isoeffective doses of X-rays and/or neutrons (XX, NN, NX, XN). In order to achieve a homogeneous radiosensitive cell population, tumours were reversibly made hypoxic by clamping ten minutes prior and during irradiation. Tumour growth delay is dependent on the sequence and on the interval. As expected the growth delay in tumours treated with neutrons only was less dependent on the interval than after pure photon irradiation. Beyond an interval of 30 minutes in the mixed beam schedules the one giving neutrons first was more effective than the one giving photons first.

  18. Effects of irradiation - fast neutrons and implantation on sintered Y sbnd Ba sbnd Cu sbnd O superconductors

    Science.gov (United States)

    Rao, K. V.; PuŹniak, R.; Chen, D.-X.; Karpe, N.; Baran, M.; Wiśniewski, A.; Pytel, K.; Szymczak, H.; Dyrbye, K.; Bøttiger, J.

    1988-06-01

    Effects of irradiation damage by fast neutrons, and nitrogen implantation on magnetic and electrical properties of Y sbnd Ba sbnd Cu sbnd O materials have been studied. The samples were subjected to a fluence of 2 × 10 17 and 1 × 10 17 neutrons / cm 2. In the implantation studies dosages of 10 15 and 10 16ions/ cm 2 of N + were used. Here we will report on the detailed changes in the magnetic hysteresis loop due to irradiation. It is found that the transport inter-grain critical current decreases with irradiation, while the critical current inside the grains is enhanced.

  19. Modification of the mesoscopic structure in neutron irradiated EPDM viewed through positron annihilation spectroscopy and dynamic mechanical analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lambri, O.A., E-mail: olambri@fceia.unr.edu.a [Instituto de Fisica Rosario - CONICET, Avda. 27 de Febrero 210 bis, 2000 Rosario (Argentina); Facultad de Ciencias Exactas, Ingenieria y Agrimensura, Universidad Nacional de Rosario, Laboratorio de Materiales, Escuela de Ingenieria Electrica, Avda. Pellegrini 250, 2000 Rosario (Argentina); Plazaola, F.; Axpe, E. [Elektrizitatea eta Elektronika Saila, Zientzia eta Teknologia Fakultatea, Euskal Herriko Unibertsitatea, P.K. 644, 48080 Bilbao (Spain); Mocellini, R.R.; Zelada-Lambri, G.I. [Facultad de Ciencias Exactas, Ingenieria y Agrimensura, Universidad Nacional de Rosario, Laboratorio de Materiales, Escuela de Ingenieria Electrica, Avda. Pellegrini 250, 2000 Rosario (Argentina); Garcia, J.A. [Departamento de Fisica Aplicada II, Facultad de Ciencias y Tecnologia, Universidad del Pais Vasco, Apdo. 644, 48080 Bilbao, Pais Vasco (Spain); Matteo, C.L.; Sorichetti, P.A. [Departamento de Fisica, Facultad de Ingenieria, Universidad de Buenos Aires, Avda. Paseo Colon 850, 1063 Buenos Aires (Argentina)

    2011-02-01

    This article focuses on the study of the mesoscopic structure in neutron irradiated EPDM both from experimental and theoretical points of view. In this work we reveal completely the modification of the mesostructure of the EPDM due to neutron irradiation, resolving volume fraction, size and distribution of the crystalline zones as a function of the irradiation dose. Positron annihilation spectroscopy and dynamic mechanical analysis techniques are applied and the results are discussed by means of new theoretical results for describing the interaction process between the crystals and amorphous zones in EPDM.

  20. Arrangement of high-energy neutron irradiation field and shielding experiment using 4 m concrete at KENS.

    Science.gov (United States)

    Nakao, N; Yashima, H; Kawai, M; Oishi, K; Nakashima, H; Masumoto, K; Matsumura, H; Sasaki, S; Numajiri, M; Sanami, T; Wang, Q; Toyoda, A; Takahashi, K; Iijima, K; Eda, K; Ban, S; Hirayama, H; Muto, S; Nunomiya, T; Yonai, S; Rasolonjatovo, D R H; Terunuma, K; Yamauchi, K; Sarkar, P K; Kim, E; Nakamura, T; Maruhashi, A

    2005-01-01

    An irradiation field of high-energy neutrons produced in the forward direction from a thick tungsten target bombarded by 500 MeV protons was arranged at the KENS spallation neutron source facility. In this facility, shielding experiment was performed with an ordinary concrete shield of 4 m thickness assembled in the irradiation room, 2.5 m downstream from the target centre. Activation detectors of bismuth, aluminium, indium and gold were inserted into eight slots inside the shield and attenuations of neutron reaction rates were obtained by measurements of gamma-rays from the activation detectors. A MARS14 Monte Carlo simulation was also performed down to thermal energy, and comparisons between the calculations and measurements show agreements within a factor of 3. This neutron field is useful for studies of shielding, activation and radiation damage of materials for high-energy neutrons, and experimental data are useful to check the accuracies of the transmission and activation calculation codes.

  1. Low temperature magnetic structure of MnSe

    Indian Academy of Sciences (India)

    J B C Efrem D'sa; P A Bhobe; K R Priolkar; A Das; P S R Krishna; P R Sarode; R B Prabhu

    2004-08-01

    In this paper we report low temperature neutron diffraction studies on MnSe in order to understand the anomalous behaviour of their magnetic and transport properties. Our study indicates that at low temperatures MnSe has two coexisting crystal structures, high temperature NaCl and hexagonal NiAs. NiAs phase appears below 266 K and is antiferromagnetically ordered at all temperatures while the NaCl phase orders antiferromagnetically at 130 K.

  2. A state-of-the-art epithermal neutron irradiation facility for neutron capture therapy

    Science.gov (United States)

    Riley, K. J.; Binns, P. J.; Harling, O. K.

    2004-08-01

    At the Massachusetts Institute of Technology (MIT) the first fission converter-based epithermal neutron beam (FCB) has proven suitable for use in clinical trials of boron neutron capture therapy (BNCT). The modern facility provides a high intensity beam together with low levels of contamination that is ideally suited for use with future, more selective boron delivery agents. Prescriptions for normal tissue tolerance doses consist of 2 or 3 fields lasting less than 10 min each with the currently available beam intensity, that are administered with an automated beam monitoring and control system to help ensure safety of the patient and staff alike. A quality assurance program ensures proper functioning of all instrumentation and safety interlocks as well as constancy of beam output relative to routine calibrations. Beam line shutters and the medical room walls provide sufficient shielding to enable access and use of the facility without affecting other experiments or normal operation of the multipurpose research reactor at MIT. Medical expertise and a large population in the greater Boston area are situated conveniently close to the university, which operates the research reactor 24 h a day for approximately 300 days per year. The operational characteristics of the facility closely match those established for conventional radiotherapy, which together with a near optimum beam performance ensure that the FCB is capable of determining whether the radiobiological promise of NCT can be realized in routine practice.

  3. Effect of 16.3 dpa neutron irradiation on fatigue lifetime of the RAFM steel EUROFER97

    Energy Technology Data Exchange (ETDEWEB)

    Materna-Morris, E., E-mail: edeltraud.materna-morris@kit.edu [KIT Karlsruhe Institute of Technology, Campus Nord, Institute for Applied Materials, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen (Germany); Moeslang, A.; Rolli, R.; Schneider, H.-C. [KIT Karlsruhe Institute of Technology, Campus Nord, Institute for Applied Materials, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen (Germany)

    2011-10-15

    Low cycle fatigue specimens of the reduced-activation martensitic/ferritic steel EUROFER97 were neutron irradiated at 250 deg. C up to an accumulated dose of 16.3 dpa. After irradiation, the specimens were push-pull fatigue tested under strain-controlled conditions at 250 deg. C to determine the impact of irradiation on lifetime, fracture behavior, and microstructure. The typical cyclic softening of martensitic/ferritic steels was observed. Furthermore, a considerable increase of lifetime after irradiation and subsequent cycling at lower strain amplitudes was remarkable. This behavior was attributed to the homogeneous distribution of stable irradiation-induced dislocation loops and small precipitates acting as barriers for the cyclic motion of dislocations, thereby influencing substantially crack initiation and crack network formation. While in the un-irradiated material push-pull fatigue sweeps the dislocations to the boundaries, a significant fraction of dislocations was fixed at irradiation-induced defects after irradiation and fatigue testing.

  4. Nanostructure evolution of neutron-irradiated reactor pressure vessel steels: Revised Object kinetic Monte Carlo model

    Science.gov (United States)

    Chiapetto, M.; Messina, L.; Becquart, C. S.; Olsson, P.; Malerba, L.

    2017-02-01

    This work presents a revised set of parameters to be used in an Object kinetic Monte Carlo model to simulate the microstructure evolution under neutron irradiation of reactor pressure vessel steels at the operational temperature of light water reactors (∼300 °C). Within a "grey-alloy" approach, a more physical description than in a previous work is used to translate the effect of Mn and Ni solute atoms on the defect cluster diffusivity reduction. The slowing down of self-interstitial clusters, due to the interaction between solutes and crowdions in Fe is now parameterized using binding energies from the latest DFT calculations and the solute concentration in the matrix from atom-probe experiments. The mobility of vacancy clusters in the presence of Mn and Ni solute atoms was also modified on the basis of recent DFT results, thereby removing some previous approximations. The same set of parameters was seen to predict the correct microstructure evolution for two different types of alloys, under very different irradiation conditions: an Fe-C-MnNi model alloy, neutron irradiated at a relatively high flux, and a high-Mn, high-Ni RPV steel from the Swedish Ringhals reactor surveillance program. In both cases, the predicted self-interstitial loop density matches the experimental solute cluster density, further corroborating the surmise that the MnNi-rich nanofeatures form by solute enrichment of immobilized small interstitial loops, which are invisible to the electron microscope.

  5. Neutron irradiation effects on the microstructural development of tungsten and tungsten alloys

    Science.gov (United States)

    Hasegawa, Akira; Fukuda, Makoto; Yabuuchi, Kiyohiro; Nogami, Shuhei

    2016-04-01

    Data on the microstructural development of tungsten (W) and tungsten rhenium (Re) alloys were obtained after neutron irradiation at 400-800 °C in the Japan Materials Testing Reactor (JMTR), the experimental fast test reactor Joyo, and the High Flux Isotope Reactor (HFIR) for irradiation damage levels in the range of 0.09-1.54 displacement per atom (dpa). Microstructural observations showed that a small amount of Re (3-5%) in W-Re alloys is effective in suppressing void formation. In W-Re alloys with Re concentrations greater than 10%, acicular precipitates are the primary structural defects. In the HFIR-irradiated specimen, in which a large amount of Re was expected to be produced by the nuclear transmutation of W to Re because of the reactor's high thermal neutron flux, voids were not observed even in pure W. The synergistic effects of displacement damage and solid transmutation elements on microstructural development are discussed, and the microstructural development of tungsten materials utilized in fusion reactors is predicted.

  6. The effect of neutron irradiation damage on the properties of grade NBG-10 graphite

    Science.gov (United States)

    Burchell, Timothy D.; Snead, Lance L.

    2007-09-01

    Nuclear block graphite-10 (NBG-10) is a medium-grain, near-isotropic graphite manufactured by SGL Carbon Company at their plant in Chedde, France. NBG-10 graphite was developed as a candidate core structural material for the pebble bed modular reactor (PBMR) currently being designed in South Africa, and for prismatic reactor concepts being developed in the USA and Europe. NBG-10 is one of several graphites included in the US-DOE Very High Temperature Reactor (VHTR) program. Thirty-six NBG-10 graphite flexure bars have been successfully irradiated in a series of 18 HFIR PTT capsules at ORNL. The capsule irradiation temperatures were 294 ± 25, 360 ± 25 and 691 ± 25 °C. The peak doses attained were 4.93, 6.67, and 6.69 × 10 25 n/m 2 [ E > 0.1 MeV] at ˜294, ˜360, and ˜691 °C, respectively. The high temperature irradiation volume and dimensional change behavior, and flexure strength and elastic modulus changes of NBG-10 were similar to other extruded, near-isotropic grades, such as H-451, which has been irradiated previously at ORNL. The low temperature (˜294 °C) irradiation volume and dimensional change behavior was also as expected for extruded graphites, i.e., exhibiting low dose swelling prior to shrinkage. This behavior was attributed to the relaxation of internal stress arising from the graphite manufacturing process and specimen machining. While the data reported here do not represent a complete database for NBG-10 graphite, they give a measure of confidence that the current generation of nuclear graphites will behave in a familiar and well understood manner.

  7. Sensors for low temperature application

    Science.gov (United States)

    Henderson, Timothy M.; Wuttke, Gilbert H.

    1977-01-01

    A method and apparatus for low temperature sensing which uses gas filled micro-size hollow glass spheres that are exposed in a confined observation area to a low temperature range (Kelvin) and observed microscopically to determine change of state, i.e., change from gaseous state of the contained gas to condensed state. By suitable indicia and classification of the spheres in the observation area, the temperature can be determined very accurately.

  8. Low temperature relations in QCD

    CERN Document Server

    Agasian, N O

    2002-01-01

    In this talk I discuss the low temperature relations for the trace of the energy-momentum tensor in QCD with two and three quarks. It is shown that the temperature derivatives of the anomalous and normal (quark massive term) contributions to the trace of the energy-momentum tensor in QCD are equal to each other in the low temperature region. Leading corrections connected with $\\pi\\pi$-interactions and thermal excitations of $K$ and $\\eta$ mesons are calculated.

  9. Subtask 12F2: Microstructural evolution of V-4Cr-4Ti during neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Chung, H.M.; Gazda, J.; Loomis, B.A. [Argonne National Lab., IL (United States)

    1995-03-01

    The objective of this work is to characterize the microstructural evolution of V-4Cr-4Ti alloy during irradiation by fast neutrons, and thereby to provide a better understanding of long-term performance of the alloy under fusion conditions. Microstructural evolution of V-4Cr-4Ti, an alloy recently shown to exhibit excellent tensile and creep properties, virtual immunity to irradiation embrittlement, and good resistance to swelling, was characterized after irradiation in a lithium environment in the Fast Flux Test Facility (FFTF) (a sodium-cooled fast reactor located in Richland, Washington) at 420, 520, and 600{degrees}C to 24-34 dpa. The primary feature of microstructural evolution during irradiation at 520 and 600{degrees}C was high-density formation of ultrafine Ti{sub 5}Si{sub 3} precipitates and short dislocations. For irradiation at 420{degrees}C, precipitation of Ti{sub 5}Si{sub 3} was negligible, and {open_quotes}black-dot{close_quotes} defects and dislocations were observed in significantly higher densities. In spite of their extremely high densities, neither the {open_quotes}black-dot{close_quotes} defects nor Ti{sub 5}Si{sub 3} precipitates are overly detrimental to ductility and toughness of the alloy, yet they very effectively suppress irradiation-induced swelling. Therefore, these features, normally observed in V-base alloys containing Ti and Si, are considered stable. Unstable microstructural modifications that are likely to degrade mechanical properties significantly were not observed, e.g., irradiation-induced formation of fine oxides, carbides, nitrides, or Cr-rich clusters. 18 refs., 4 figs., 1 tab.

  10. Progress on using deuteron-deuteron fusion generated neutrons for 40Ar/39Ar sample irradiation

    Science.gov (United States)

    Rutte, Daniel; Renne, Paul R.; Becker, Tim; Waltz, Cory; Ayllon Unzueta, Mauricio; Zimmerman, Susan; Hidy, Alan; Finkel, Robert; Bauer, Joseph D.; Bernstein, Lee; van Bibber, Karl

    2017-04-01

    We present progress on the development and proof of concept of a deuteron-deuteron fusion based neutron generator for 40Ar/39Ar sample irradiation. Irradiation with deuteron-deuteron fusion neutrons is anticipated to reduce Ar recoil and Ar production from interfering reactions. This will allow dating of smaller grains and increase accuracy and precision of the method. The instrument currently achieves neutron fluxes of ˜9×107 cm-2s-1 as determined by irradiation of indium foils and use of the activation reaction 115In(n,n')115mIn. Multiple foils and simulations were used to determine flux gradients in the sample chamber. A first experiment quantifying the loss of 39Ar is underway and will likely be available at the time of the presentation of this abstract. In ancillary experiments via irradiation of K salts and subsequent mass spectrometric analysis we determined the cross-sections of the 39K(n,p)39Ar reaction at ˜2.8 MeV to be 160 ± 35 mb (1σ). This result is in good agreement with bracketing cross-section data of ˜96 mb at ˜2.45 MeV and ˜270 mb at ˜4 MeV [Johnson et al., 1967; Dixon and Aitken, 1961 and Bass et al. 1964]. Our data disfavor a much lower value of ˜45 mb at 2.59 MeV [Lindström & Neuer, 1958]. In another ancillary experiment the cross section for 39K(n,α)36Cl at ˜2.8 MeV was determined as 11.7 ± 0.5 mb (1σ), which is significant for 40Ar/39Ar geochronology due to subsequent decay to 36Ar as well as for the determination of production rates of cosmogenic 36Cl. Additional experiments resolving the cross section functions on 39K between 1.5 and 3.6 MeV are on their way using the LICORNE neutron source of the IPN Orsay tandem accelerator. Results will likely be available at the time of the presentation of this abstract. While the neutron generator is designed for fluxes of ˜109 cm-2s-1, arcing in the sample chamber currently limits the power—straightforwardly correlated to the neutron flux—the generator can safely be run at. Further

  11. Evaluation of D(d,n)3 He reaction neutron source models for BNCT irradiation system design

    Institute of Scientific and Technical Information of China (English)

    YAO Ze'en; LUO Peng; Tooru KOBAYASHI; Gerard BENGUA

    2007-01-01

    A mathematical method was developed to calculatc the yield.energy spectrum and angular distribution of neutrons from D(d,n)3 He(D-D)reaction in a thick deuterium-titanium target for incident deuterons in energies lower than 1.0MeV.The data of energy spectrum and angular distribution wefe applied to set up the neutron source model for the beam-shaping-assembly(BSA)design of Boron-Neutron-Capture-Therapy(BNCT)using MCNP-4C code.Three cases of D-D neutron source corresponding to incident deuteron energy of 1000.400 and 150 kaV were investigated.The neutron beam characteristics were compared with the model of a 2.45 MeV mono-energetic and isotropic neutron source using an example BSA designed for BNCT irradiation.The results show significant differences in the neutron beam characteristics,particularly the fast neutron component and fast neutron dose in air,between the non-isotropic neutron source model and the 2.5 MeV mono-energetic and isotropic neutron source model.

  12. Study of the temperature evolution of defect agglomerates in neutron irradiated molybdenum single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Lambri, O.A. [Instituto de Fisica Rosario. Member of the CONICET' s Research Staff, Avda. Pellegrini 250, (2000) Rosario, Santa Fe (Argentina); Facultad de Ciencias Exactas, Ingenieria y Agrimensura, Universidad Nacional de Rosario, Laboratorio de Materiales, Escuela de Ingenieria Electrica, Avda. Pellegrini 250, (2000) Rosario, Santa Fe (Argentina)], E-mail: olambri@fceia.unr.edu.ar; Zelada-Lambri, G.I. [Facultad de Ciencias Exactas, Ingenieria y Agrimensura, Universidad Nacional de Rosario, Laboratorio de Materiales, Escuela de Ingenieria Electrica, Avda. Pellegrini 250, (2000) Rosario, Santa Fe (Argentina); Cuello, G.J. [Institut Laue Langevin, 6, rue Jules Horowitz, BP 156, 38042 Grenoble (France); Departamento de Fisica Aplicada II, Facultad de Ciencias y Tecnologia, Universidad del Pais Vasco, Apdo. 644, 48080 Bilbao, Pais Vasco (Spain); Bozzano, P.B. [Laboratorio de Microscopia Electronica. Unidad de Actividad Materiales, Centro Atomico Constituyentes, Comision Nacional de Energia Atomica, Avda. Gral. Paz 1499, (1650) San Martin (Argentina); Garcia, J.A. [Departamento de Fisica Aplicada II, Facultad de Ciencias y Tecnologia, Universidad del Pais Vasco, Apdo. 644, 48080 Bilbao, Pais Vasco (Spain)

    2009-04-15

    Small angle neutron scattering as a function of temperature, differential thermal analysis, electrical resistivity and transmission electron microscopy studies have been performed in low rate neutron irradiated single crystalline molybdenum, at room temperature, for checking the evolution of the defects agglomerates in the temperature interval between room temperature and 1200 K. The onset of vacancies mobility was found to happen in temperatures within the stage III of recovery. At around 550 K, the agglomerates of vacancies achieve the largest size, as determined from the Guinier approximation for spherical particles. In addition, the decrease of the vacancy concentration together with the dissolution of the agglomerates at temperatures higher than around 920 K was observed, which produce the release of internal stresses in the structure.

  13. Study of the relative dose-response of BANG-3® polymer gel dosimeters in epithermal neutron irradiation

    Science.gov (United States)

    Uusi-Simola, J.; Savolainen, S.; Kangasmäki, A.; Heikkinen, S.; Perkiö, J.; Abo Ramadan, U.; Seppälä, T.; Karila, J.; Serén, T.; Kotiluoto, P.; Sorvari, P.; Auterinen, I.

    2003-09-01

    Polymer gels have been reported as a new, potential tool for dosimetry in mixed neutron-gamma radiation fields. In this work, BANG-3 (MGS Research Inc.) gel vials from three production batches were irradiated with 6 MV photons of a Varian Clinac 2100 C linear accelerator and with the epithermal neutron beam of the Finnish boron neutron capture therapy (BNCT) facility at the FiR 1 nuclear reactor. The gel is tissue equivalent in main elemental composition and density and its T2 relaxation time is dependent on the absorbed dose. The T2 relaxation time map of the irradiated gel vials was measured with a 1.5 T magnetic resonance (MR) scanner using spin echo sequence. The absorbed doses of neutron irradiation were calculated using DORT computer code, and the accuracy of the calculational model was verified by measuring gamma ray dose rate with thermoluminescent dosimeters and 55Mn(n,gamma) activation reaction rate with activation detectors. The response of the BANG-3 gel dosimeter for total absorbed dose in the neutron irradiation was linear, and the magnitude of the response relative to the response in the photon irradiation was observed to vary between different gel batches. The results support the potential of polymer gels in BNCT dosimetry, especially for the verification of two- or three-dimensional dose distributions.

  14. Observation of neutron spectrum from deuterated plastic irradiated by 100 picosecond and sub-picosecond ultra-intense laser.

    Science.gov (United States)

    Izumi, N.; Miyoshi, K.; Takahashi, K.; Habara, H.; Kodama, R.; Sentoku, S.; Fujita, H.; Kitagawa, Y.; Katou, Y.; Mima, K.; Tanaka, K. A.

    1998-11-01

    For understanding of the fundamental physics of the fast ignition, it is crucial to investigate the fast ion production in a high density plasma irradiated by an ultra-intense laser. The energy spectrum of the neutrons produced in the deuterated target reflects the energy spectrum of fast deuterons accelerated in the interacting region. Due to high penetration ability of fast neutron, the neutron spectra directly bring out the information of the hot ions from the high density plasma. We have observed 10^6 of the DD neutrons produced in a deuterated polystyrene (C8D8)x target irradiated by the 500-fs intense laser (up to 10^19 W/cm^2). The fast neutron spectra were measured by multi-channel time-of-flight neutron spectrometer (MANDALA) at the GEKKO XII laser facility of Osaka University. The spectrometer has two sets of 421 channel detector arrays which were located at 90 and 54.7 degrees with respect to the irradiation axis. The observed spectral width of DD neutrons were 1.35 MeV in full width of half maximum. This spectrum result from the fusion reaction created by accelerated ions which have energy about 300 keV. We report the details of the experimental results and the quantitative analysis using particle in cell code.

  15. Cavity nucleation and growth during helium implantation and neutron irradiation of Fe and steel

    DEFF Research Database (Denmark)

    Eldrup, Morten Mostgaard; Singh, Bachu Narain

    2013-01-01

    The present work concerns investigations of damage accumulation during helium implantation of pure iron and the reduced activation ferritic-martensitic steel 'EUROFER 97' at 323K and 623K as well as during neutron irradiation with or without prior helium implantation. The defect microstructure......, in particular the cavities, was characterized using Positron Annihilation Lifetime Spectroscopy (PALS) and Transmission Electron Microscopy (TEM). The PALS investigations reveal a clear difference between the He implantation effects in Fe and EUROFER 97 at both temperatures. For both materials the mean positron...

  16. Isotopic Abundances and Ratios in Arsenic Irradiated by High-Energy Neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Parker, W. E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Hall, J. M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2010-06-07

    This document provides derivations of the 73As, 74As and 75As isotopic abundances and ratios in an arsenic sample irradiated by high-energy (14 MeV) neutrons for 0 ≤ t ≤ T, where T is short compared to the natural decay times of the reaction products (t1/2 (73As) ~ 80.3 d, t1/2 (74As) ~ 17.8 d). The document also outlines the historic approach used to analyze arsenic data from experiments.

  17. Defect-induced magnetism in neutron irradiated 6H-SiC single crystals.

    Science.gov (United States)

    Liu, Yu; Wang, Gang; Wang, Shunchong; Yang, Jianhui; Chen, Liang; Qin, Xiubo; Song, Bo; Wang, Baoyi; Chen, Xiaolong

    2011-02-25

    Defect-induced magnetism is firstly observed in neutron irradiated SiC single crystals. We demonstrated that the intentionally created defects dominated by divacancies (V(Si)V(C)) are responsible for the observed magnetism. First-principles calculations revealed that defect states favor the formation of local moments and the extended tails of defect wave functions make long-range spin couplings possible. Our results confirm the existence of defect-induced magnetism, implying the possibility of tuning the magnetism of wide band-gap semiconductors by defect engineering.

  18. High temperature nanoindentation hardness and Young's modulus measurement in a neutron-irradiated fuel cladding material

    Science.gov (United States)

    Kese, K.; Olsson, P. A. T.; Alvarez Holston, A.-M.; Broitman, E.

    2017-04-01

    Nanoindentation, in combination with scanning probe microscopy, has been used to measure the hardness and Young's modulus in the hydride and matrix of a high burn-up neutron-irradiated Zircaloy-2 cladding material in the temperature range 25-300 °C. The matrix hardness was found to decrease only slightly with increasing temperature while the hydride hardness was essentially constant within the temperature range. Young's modulus decreased with increasing temperature for both the hydride and the matrix of the high burn-up fuel cladding material. The hydride Young's modulus and hardness were higher than those of the matrix in the temperature range.

  19. Neutron beam irradiation study of workload dependence of SER in a microprocessor

    Energy Technology Data Exchange (ETDEWEB)

    Michalak, Sarah E [Los Alamos National Laboratory; Graves, Todd L [Los Alamos National Laboratory; Hong, Ted [STANFORD; Ackaret, Jerry [IBM; Sonny, Rao [IBM; Subhasish, Mitra [STANFORD; Pia, Sanda [IBM

    2009-01-01

    It is known that workloads are an important factor in soft error rates (SER), but it is proving difficult to find differentiating workloads for microprocessors. We have performed neutron beam irradiation studies of a commercial microprocessor under a wide variety of workload conditions from idle, performing no operations, to very busy workloads resembling real HPC, graphics, and business applications. There is evidence that the mean times to first indication of failure, MTFIF defined in Section II, may be different for some of the applications.

  20. Defects in Fast-Neutron Irradiated Nitrogen-Doped Czochralski Silicon after Annealing at High Temperature

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Fast-neutron irradiated nitrogen-doped Czochralski silicon (NCZ-Si) was annealed at 1100 ℃ for different time, then FTIR and optical microscope were used to study the behavior of oxygen. It is found that [Oi] increase at the early stage then decrease along with the increasing of anneal time. High density induced-defects can be found in the cleavage plane. By comparing NCZ-Si with Czochralski silicon (CZ-Si), [Oi] in NCZ-Si decrease more after anneal 24 h.

  1. Comparison of neutron and gamma irradiation effects on KU1 fused silica monitored by electron paramagnetic resonance

    Energy Technology Data Exchange (ETDEWEB)

    Bravo, D. [Department Fisica de Materiales, Universidad Autonoma de Madrid, E-28049 Madrid (Spain)], E-mail: david.bravo@uam.es; Lagomacini, J.C. [Department Fisica de Materiales, Universidad Autonoma de Madrid, E-28049 Madrid (Spain); Leon, M.; Martin, P. [Materiales para Fusion, CIEMAT, Avda. Complutense 22, E-28040 Madrid (Spain); Martin, A. [Department Fisica e Instalaciones, ETS Arquitectura UPM, E-28040 Madrid (Spain); Lopez, F.J. [Department Fisica de Materiales, Universidad Autonoma de Madrid, E-28049 Madrid (Spain); Ibarra, A. [Materiales para Fusion, CIEMAT, Avda. Complutense 22, E-28040 Madrid (Spain)

    2009-06-15

    Electron paramagnetic resonance (EPR) studies have been carried out on KU1 fused silica irradiated with neutrons at fluences 10{sup 21} and 10{sup 22} n/m{sup 2}, and gamma-ray doses up to 12 MGy. The effects of post-irradiation thermal annealing treatments, up to 850 deg. C, have also been investigated. Paramagnetic oxygen-related defects (POR and NBOHC) and E'-type defects have been identified and their concentration has been measured as a function of neutron fluence, gamma dose and post-irradiation annealing temperature. It is found that neutrons at the highest fluence generate a much higher concentration of defects (mainly E' and POR, both at concentrations about 5 x 10{sup 18} spins/cm{sup 3}) than gamma irradiations at the highest dose (mainly E' at a concentration about 4 x 10{sup 17} spins/cm{sup 3}). Moreover, for gamma-irradiated samples a lower treatment temperature (about 400 deg. C) is required to annihilate most of the observed defects than for neutron-irradiated ones (about 600 deg. C)

  2. Influence of nickel and beryllium content on swelling behavior of copper irradiated with fast neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Singh, B.N.; Garner, F.A.; Edwards, D.J. [Pacific Northwest National Lab., Richland, WA (United States); Evans, J.H.

    1996-10-01

    In the 1970`s, the effects of nickel content on the evolution of dislocation microstructures and the formation and growth of voids in Cu-Ni alloys were studied using 1 MeV electrons in a high voltage electron microscope. The swelling rate was found to decrease rapidly with increasing nickel content. The decrease in the swelling rate was associated with a decreasing void growth rate with increasing nickel content at irradiation temperatures up to 450{degrees}C. At 500{degrees}C, both void size and swelling rate were found to peak at 1 and 2% Ni, respectively, and then to decrease rapidly with increasing nickel content. However, recent work has demonstrated that the swelling behavior of Cu-5%Ni irradiated with fission neutrons is very similar for that of pure copper. The present experiments were designed to investigate this apparent discrepancy.

  3. Radiation Damage and Recovery in Neutron-Irradiated MgO Crystal

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    MgO single crystal was irradiated by neutron up to a dose of 5.74×1018 cm-2. The radiation damage and its recovery were studied by means of UV-VIS and EM spectroscopy. The results indicate that the irradiation generates large amount of optically detectable defects such as single anion vacancies (F+ center), anion divacancies (F2) and some higher order defects. Through isochronal annealing, these defects started a series of processes of diminishing and transforming, and finally all disappeared while annealing at 900 ℃. It seems that the absorption bands of 573 nm are resulted from a higher order and more complex aggregated center than that of 424, 451 nm bands.

  4. Thermal stability of neutron irradiation effects on KU1 fused silica

    Energy Technology Data Exchange (ETDEWEB)

    Leon, M. [Materiales Para Fusion, CIEMAT, Avenida Complutense 22, Madrid (Spain)], E-mail: monica.leon@ciemat.es; Martin, P. [Materiales Para Fusion, CIEMAT, Avenida Complutense 22, Madrid (Spain); Bravo, D.; Lopez, F.J. [Departamento Fisica de Materiales, Universidad Autonoma, Cantoblanco, Madrid (Spain); Ibarra, A. [Materiales Para Fusion, CIEMAT, Avenida Complutense 22, Madrid (Spain); Rascon, A. [Metrologia Radiaciones Ionizantes, CIEMAT, Avenida Complutense 22, Madrid (Spain); Mota, F. [Instituto de Fusion Nuclear, DENIM, Universidad Politecnica, Madrid (Spain)

    2008-03-15

    Optical absorption spectra of neutron irradiated (10{sup 21} n/m{sup 2} and 10{sup 22} n/m{sup 2}) KU1 quartz glass samples have been measured. The effects of post-irradiation isochronal thermal annealing, up to 850 deg. C, have been investigated. The general effect of the isochronal annealing is a decrease in the optical absorption bands as the temperature increases. Optical absorption bands have been identified with known defects from the literature, and their concentration temperature dependence has been analyzed. While the annealing curves of the E' and non-bridging oxygen hole centres (NBOHC) are similar, that corresponding to oxygen deficiency centres (ODC(II)) is quite different suggesting that the recombination of E' and NBOHC is part of the same process whereas the recombination of ODC is controlled by the presence of another undetected defect.

  5. Investigation of the agglomeration and amorphous transformation effects of neutron irradiation on the nanocrystalline silicon carbide (3C-SiC) using TEM and SEM methods

    Energy Technology Data Exchange (ETDEWEB)

    Huseynov, Elchin M., E-mail: elchin.h@yahoo.com [Department of Nanotechnology and Radiation Material Science, National Nuclear Research Center, Inshaatchilar pr. 4, AZ 1073 Baku (Azerbaijan); Institute of Radiation Problems of Azerbaijan National Academy of Sciences, B.Vahabzade 9, AZ 1143 Baku (Azerbaijan)

    2017-04-01

    Nanocrystalline 3C-SiC particles irradiated by neutron flux during 20 h in TRIGA Mark II light water pool type research reactor. Silicon carbide nanoparticles were analyzed by Scanning Electron Microscope (SEM) and Transmission Electron Microscopy (TEM) devices before and after neutron irradiation. The agglomeration of nanoparticles was studied comparatively before and after neutron irradiation. After neutron irradiation the amorphous layer surrounding the nanoparticles was analyzed in TEM device. Neutron irradiation defects in the 3C-SiC nanoparticles and other effects investigated by TEM device. The effect of irradiation on the crystal structure of the nanomaterial was studied by selected area electron diffraction (SAED) and electron diffraction patterns (EDP) analysis.

  6. Investigation of the agglomeration and amorphous transformation effects of neutron irradiation on the nanocrystalline silicon carbide (3C-SiC) using TEM and SEM methods

    Science.gov (United States)

    Huseynov, Elchin M.

    2017-04-01

    Nanocrystalline 3C-SiC particles irradiated by neutron flux during 20 h in TRIGA Mark II light water pool type research reactor. Silicon carbide nanoparticles were analyzed by Scanning Electron Microscope (SEM) and Transmission Electron Microscopy (TEM) devices before and after neutron irradiation. The agglomeration of nanoparticles was studied comparatively before and after neutron irradiation. After neutron irradiation the amorphous layer surrounding the nanoparticles was analyzed in TEM device. Neutron irradiation defects in the 3C-SiC nanoparticles and other effects investigated by TEM device. The effect of irradiation on the crystal structure of the nanomaterial was studied by selected area electron diffraction (SAED) and electron diffraction patterns (EDP) analysis.

  7. Image processing analysis of nuclear track parameters for CR-39 detector irradiated by thermal neutron

    Energy Technology Data Exchange (ETDEWEB)

    Al-Jobouri, Hussain A., E-mail: hahmed54@gmail.com; Rajab, Mustafa Y., E-mail: mostafaheete@gmail.com [Department of Physics, College of Science, AL-Nahrain University, Baghdad (Iraq)

    2016-03-25

    CR-39 detector which covered with boric acid (H{sub 3}Bo{sub 3}) pellet was irradiated by thermal neutrons from ({sup 241}Am - {sup 9}Be) source with activity 12Ci and neutron flux 10{sup 5} n. cm{sup −2}. s{sup −1}. The irradiation times -T{sub D} for detector were 4h, 8h, 16h and 24h. Chemical etching solution for detector was sodium hydroxide NaOH, 6.25N with 45 min etching time and 60 C° temperature. Images of CR-39 detector after chemical etching were taken from digital camera which connected from optical microscope. MATLAB software version 7.0 was used to image processing. The outputs of image processing of MATLAB software were analyzed and found the following relationships: (a) The irradiation time -T{sub D} has behavior linear relationships with following nuclear track parameters: i) total track number - N{sub T} ii) maximum track number - MRD (relative to track diameter - D{sub T}) at response region range 2.5 µm to 4 µm iii) maximum track number - M{sub D} (without depending on track diameter - D{sub T}). (b) The irradiation time -T{sub D} has behavior logarithmic relationship with maximum track number - M{sub A} (without depending on track area - A{sub T}). The image processing technique principally track diameter - D{sub T} can be take into account to classification of α-particle emitters, In addition to the contribution of these technique in preparation of nano- filters and nano-membrane in nanotechnology fields.

  8. Subtask 12F1: Effect of neutron irradiation on swelling of vanadium-base alloys

    Energy Technology Data Exchange (ETDEWEB)

    Chung, H.M.; Loomis, B.A.; Smith, D.L. [Argonne National Lab., IL (United States)

    1995-03-01

    The objective of this work is to determine the effects of neutron irradiation on the density change, void distribution, and microstructural evolution of vanadium-base alloys. Swelling behavior and microstructural evolution of V-Ti, V-Cr-Ti, and V-Ti-Si alloys were investigated after irradiation at 420-600{degrees}C up to 114 dpa. The alloys exhibited swelling maxima between 30 and 80 dpa and swelling decreased on irradiation to higher dpa. This is in contrast to the monotonically increasing swelling of binary alloys that contain Fe, Ni, Cr, Mo, W, and Si. Precipitation of dense Ti{sub 5}Si{sub 3} promotes good resistance to swelling of the Ti-containing alloys, and it was concluded that Ti of >3 wt.% and 400-1000 wppm Si are necessary to effectively suppress swelling. Swelling was minimal in V-4Cr-4Ti, identified as the most promising alloy based on good mechanical properties and superior resistance to irradiation embrittlement. 18 refs., 6 figs., 1 tab.

  9. Views of TAGSI on effects of neutron irradiation on ductile tearing in ferritic steels

    Energy Technology Data Exchange (ETDEWEB)

    Knott, J.F. [School of Metallurgy and Materials, University of Birmingham, Birmingham B15 2TT (United Kingdom); Lidbury, D.P.G. [Serco Technical and Assurance Services, Walton House, 404 Faraday Street, Birchwood Park, Warrington WA3 6GA (United Kingdom)], E-mail: david.lidbury@serco.com

    2009-07-15

    The paper reviews information pertaining to effects of neutron irradiation on 'upper-shelf' Charpy impact behaviour and on elastic/plastic fracture mechanics characterising parameters, again for 'upper shelf' conditions, in which the initiation and early growth of a crack involve ductile tearing. The hardening and associated reduction in strain-hardening capacity induced by irradiation gives rise to a decrease in Charpy upper shelf energy. Effects on J-based parameters are more complicated. The material resistance parameters tend to increase for low dose, but decrease at high dose, when the decrease in crack-tip ductility outweighs the effect of hardening. High doses can produce 'fast shear' fracture, which propagates rapidly and is therefore more likely to induce brittle cleavage fracture. The situation is exacerbated if the irradiation also promotes inter-granular segregation and fracture, hence reducing the local brittle fracture stress. For the levels of irradiation experienced by the types of UK civil reactors in operation, no fracture instability is expected to arise as a result of ductile fracture mechanisms alone.

  10. An investigation of methods for neutron dose measurement in high temperature irradiation fields

    Energy Technology Data Exchange (ETDEWEB)

    Kosako, Toshisou; Sugiura, Nobuyuki [Tokyo Univ. (Japan); Kudo, Kazuhiko [Kyushu Univ., Fukuoka (Japan)] [and others

    2000-10-01

    The Japan Atomic Energy Research Institute (JAERI) has been conducting the innovative basic research on high temperature since 1994, which is a series of high temperature irradiation studies using the High Temperature Engineering Test Reactor (HTTR). 'The Task Group for Evaluation of Irradiation Dose under High Temperature Radiation' was founded in the HTTR Utilization Research Committee, which is the promoting body of the innovative basic research. The present report is a summary of investigation which has been made by the Task Group on the present status and subjects of research and development of neutron detectors in high temperature irradiation fields, in view of contributing to high temperature irradiation research using the HTTR. Detectors investigated here in the domestic survey are the following five kinds of in-core detectors: 1) small fission counter, 2) small fission chamber, 3) self-powered detector, 4) activation detector, and 5) optical fiber. In addition, the research and development status in Russia has been investigated. The present report will also be useful as nuclear instrumentation of high temperature gas-cooled reactors. (author)

  11. Szilard-Chalmers effect in solid HIO4.2H2O by neutron irradiation

    Science.gov (United States)

    Takriti, Salaheddin

    1992-09-01

    The Szilard-Chalmers effect in solid was investigated. In order to study the initial distribution of (128)IO4 as a function of neutron flux, samples were irradiated utilizing both the manual vertical irradiation channel and the thermal column of the ET-RR-1 Research Reactor in Egypt. The initial retention was reached a maximum of 40% after 120 minutes at 5.5 x 10(sup 8) ns(exp -1)cm(exp -2). The data was analyzed using a first order reaction. As a result, the activation energy and the vibration constant were found to be E = 0.95 eV and K = 2.82 x 10(sup 11), respectively. Kinetics comparison of the dehydration and irradiation reactions for this solid shows disorder in the crystallographic form. Such disorder may be the result of dehydration or irradiation reaction, where the loss of water molecule will lead to formation of vacancies which, in turn, are responsible for the distribution process.

  12. EL2-related defects in neutron irradiated GaAs/sub 1//sub -x/P/sub x/ alloys

    Energy Technology Data Exchange (ETDEWEB)

    Munoz, E.; Garcia, F.; Jimenez, B.; Calleja, E.; Gomez, A.; Alcober, V.

    1985-10-15

    The generation of EL2-related defects in GaAsP alloys by fast neutron irradiation has been studied through deep level transient spectroscopy and photocapacitance techniques. After irradiation p-n junctions were not annealed at high temperatures. In the composition range x>0.4, fast neutrons generate a broad center at E/sub c/-0.7 eV that it is suggested to belong to the EL2 family. The presence of photocapacitance quenching effects has been taken as a preliminary fingerprint to make the above assignment. From computer analysis of the nonexponential transient capacitance waveforms, evidence that neutron irradiation creates a family of midgap levels, EL2-related, is found.

  13. Neutron irradiation effects on domain wall mobility and reversibility in lead zirconate titanate thin films

    Energy Technology Data Exchange (ETDEWEB)

    Graham, Joseph T. [Nuclear Engineering Teaching Laboratory, University of Texas at Austin, Austin, Texas 78758 (United States); Electronic, Optic and Nano Materials Department, Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); Brennecka, Geoff L.; Ihlefeld, Jon F. [Electronic, Optic and Nano Materials Department, Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); Ferreira, Paulo [Materials Science and Engineering Program, University of Texas at Austin, Austin, Texas 78751 (United States); Small, Leo [Electronic, Optic and Nano Materials Department, Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Duquette, David [Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Apblett, Christopher [Advanced Power Sources R and D Department, Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); Landsberger, Sheldon [Nuclear Engineering Teaching Laboratory, University of Texas at Austin, Austin, Texas 78758 (United States)

    2013-03-28

    The effects of neutron-induced damage on the ferroelectric properties of thin film lead zirconate titanate (PZT) were investigated. Two sets of PbZr{sub 0.52}Ti{sub 0.48}O{sub 3} films of varying initial quality were irradiated in a research nuclear reactor up to a maximum 1 MeV equivalent neutron fluence of (5.16 {+-} 0.03) Multiplication-Sign 10{sup 15} cm{sup -2}. Changes in domain wall mobility and reversibility were characterized by polarization-electric field measurements, Rayleigh analysis, and analysis of first order reversal curves (FORC). With increasing fluence, extrinsic contributions to the small-signal permittivity diminished. Additionally, redistribution of irreversible hysterons towards higher coercive fields was observed accompanied by the formation of a secondary hysteron peak following exposure to high fluence levels. The changes are attributed to the radiation-induced formation of defect dipoles and other charged defects, which serve as effective domain wall pinning sites. Differences in damage accumulation rates with initial film quality were observed between the film sets suggesting a dominance of pre-irradiation microstructure on changes in macroscopic switching behavior.

  14. Cluster dynamics modeling of accumulation and diffusion of helium in neutron irradiated tungsten

    Energy Technology Data Exchange (ETDEWEB)

    Li, Y.G.; Zhou, W.H.; Huang, L.F. [Key Laboratory for Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (China); Zeng, Z., E-mail: zzeng@theory.issp.ac.cn [Key Laboratory for Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (China); Ju, X. [Department of Physics, University of Science and Technology Beijing, Beijing 100083 (China)

    2012-12-15

    A cluster dynamics model based on rate theory has been developed to study the accumulation and diffusion processes of helium in tungsten under synergistic effects of helium implantation and neutron irradiation. By including self-interstitial atoms, vacancies and helium atoms as well as their clusters and further using more reliable parameters, the evolution of different types of defects with time and depth is investigated. The calculated results are comparable with experiments. The cases of helium plasma corresponding to the first wall and to the divertor are taken into account. The accumulation and diffusion behaviors of helium in tungsten are illustrated by the time and depth dependence of helium concentration in tungsten with or without the neutron irradiation, the contribution of different types of helium clusters/complexes to helium concentration and the depth profiles of different mobile defects and helium-vacancy complexes. It is concluded that the competition of trapping and diffusion effects dominates the behavior of helium atoms in tungsten for these two typical cases. Understanding these mechanisms is important for estimating damages to the plasma-facing materials.

  15. Ammonia synthesis at low temperatures

    DEFF Research Database (Denmark)

    Rod, Thomas Holm; Logadottir, Ashildur; Nørskov, Jens Kehlet

    2000-01-01

    have been carried out to evaluate its feasibility. The calculations suggest that it might be possible to catalytically produce ammonia from molecular nitrogen at low temperatures and pressures, in particular if energy is fed into the process electrochemically. (C) 2000 American Institute of Physics........ In contrast to the biological process, the industrial process requires high temperatures and pressures to proceed, and an explanation of this important difference is discussed. The possibility of a metal surface catalyzed process running at low temperatures and pressures is addressed, and DFT calculations...

  16. Modification of chemical, optical and structural properties of Bayfol CR-6-2 using gamma and neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Shehata, Mohamed M.; Radwan, Samh I.; Hassan, Amin [Atomic Energy Authority, Cairo (Egypt). Nuclear Research Centre; Waly, Sayed A. [Atomic Energy Authority, Cairo (Egypt). Second Research Reactor; Badawy, Zaynab M. [Atomic Energy Authority, Cairo (Egypt). Experimental Nuclear Physics Dept.

    2016-08-01

    The effects of gamma and neutron irradiations on the chemical, optical and structural properties of Bayfol CR-6-2 were investigated. The samples were irradiated by γ-rays from a {sup 60}Co source at various doses ranging between 16 and 900 kGy at room temperature in atmospheric air. For neutrons, an Am-Be neutron facility was used for the sample irradiation in thermal mode which had an activity of 185 GBq. Samples were irradiated with different doses of neutrons ranging from 15.7 to 564.2 mGy. The changes induced were analyzed using UV-Vis and Fourier transform infrared (FTIR) spectrometry. The results demonstrated an occurrence of oxidative degradation, resulting in the formation of carbonyl groups at 1700 cm{sup -1}. Simultaneous thermo-gravimetric investigation (TGA) has been performed on the samples of 0.3 mm thickness. The results obtained indicate that cross-linking predominates at small neutron doses and main chain scission happens at higher doses.

  17. Neutron irradiation damage effect on superconducting and normal state properties of the YBa 2Cu 3O 7 system

    Science.gov (United States)

    Przysłupski, P.; Wiśniewski, A.; Koleśnik, S.; Dobrowolski, W.; Pajączkowska, A.; Pytel, K.; Pytel, B.

    1988-06-01

    Effect of irradiation by fast neutrons on superconducting and normal state properties of the YBa 2Cu 3O 7 samples is presented. Transport measurements showed a degradation of all superconducting parameters, especially the transport critical current density. Critical current densities obtained from magnetization data exhibited a substantial increase / about 15 times at 77 K and H = 10 kOe/ after the irradiation with the fluence in the range 2.4·10 17 ÷ 8.7 · 10 17 n/cm 2. Such an anomalous bahavior is explained in terms of neutron created defects at intergrain regions and improved intragrain pinning.

  18. In-situ, Gate Bias Dependent Study of Neutron Irradiation Effects on AlGaN/GaN HFETs

    Science.gov (United States)

    2010-03-01

    Applied Physics Letters , vol.82, no. 22, 2 June 2008. 72 [12] D. M. Sathaiya, et al., "Thermionic trap-assisted tunneling model and its... Letters , vol. 25, no. 3, 1045, 2008. [18] A. Y. Polyakov , et al., “Neutron irradiation effects on electrical properties and deep-level spectra in...undoped n-AlGaN/GaN heterostructures,” Journal of Applied Physics , vol. 98, 033529, 2005. [19] A. Y. Polyakov , et al., “Neutron irradiation effects in

  19. Design and Demonstration of a Material-Plasma Exposure Target Station for Neutron Irradiated Samples

    Energy Technology Data Exchange (ETDEWEB)

    Rapp, Juergen [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Aaron, A. M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bell, Gary L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Burgess, Thomas W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ellis, Ronald James [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Giuliano, D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Howard, R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kiggans, James O. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Lessard, Timothy L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ohriner, Evan Keith [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Perkins, Dale E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Varma, Venugopal Koikal [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-10-20

    Fusion energy is the most promising energy source for the future, and one of the most important problems to be solved progressing to a commercial fusion reactor is the identification of plasma-facing materials compatible with the extreme conditions in the fusion reactor environment. The development of plasma–material interaction (PMI) science and the technology of plasma-facing components are key elements in the development of the next step fusion device in the United States, the so-called Fusion Nuclear Science Facility (FNSF). All of these PMI issues and the uncertain impact of the 14-MeV neutron irradiation have been identified in numerous expert panel reports to the fusion community. The 2007 Greenwald report classifies reactor plasma-facing materials (PFCs) and materials as the only Tier 1 issues, requiring a “. . . major extrapolation from the current state of knowledge, need for qualitative improvements and substantial development for both the short and long term.” The Greenwald report goes on to list 19 gaps in understanding and performance related to the plasma–material interface for the technology facilities needed for DEMO-oriented R&D and DEMO itself. Of the 15 major gaps, six (G7, G9, G10, G12, G13) can possibly be addressed with ORNL’s proposal of an advanced Material Plasma Exposure eXperiment. Establishing this mid-scale plasma materials test facility at ORNL is a key element in ORNL’s strategy to secure a leadership role for decades of fusion R&D. That is to say, our end goal is to bring the “signature facility” FNSF home to ORNL. This project is related to the pre-conceptual design of an innovative target station for a future Material–Plasma Exposure eXperiment (MPEX). The target station will be designed to expose candidate fusion reactor plasma-facing materials and components (PFMs and PFCs) to conditions anticipated in fusion reactors, where PFCs will be exposed to dense high-temperature hydrogen plasmas providing steady

  20. Structural and chemical evolution in neutron irradiated and helium-injected ferritic ODS PM2000 alloy

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Hee Joon; Edwards, Dan J.; Kurtz, Richard J.; Yamamoto, Takuya; Wu, Yuan; Odette, G. Robert

    2017-02-01

    An investigation of the influence of helium on damage evolution under neutron irradiation of an 11 at% Al, 19 at% Cr ODS ferritic PM2000 alloy was carried out in the High Flux Isotope Reactor (HFIR) using a novel in situ helium injection (ISHI) technique. Helium was injected into adjacent TEM discs from thermal neutron 59Ni(nth, 59Ni(nth,α) reactions in a thin NiAl layer. The PM2000 undergoes concurrent displacement damage from the high-energy neutrons. The ISHI technique allows direct comparisons of regions with and without high concentrations of helium since only the side coated with the NiAl experiences helium injection. The corresponding microstructural and microchemical evolutions were characterized using both conventional and scanning transmission electron microscopy techniques. The evolutions observed include formation of dislocation loops and associated helium bubbles, precipitation of a variety of phases, amorphization of the Al2YO3 oxides (which also variously contained internal voids), and several manifestations of solute segregation. Notably, high concentrations of helium had a significant effect on many of these diverse phenomena. These results on PM2000 are compared and contrasted to the evolution of so-called nanostructured ferritic alloys (NFA).

  1. Structural and chemical evolution in neutron irradiated and helium-injected ferritic ODS PM2000 alloy

    Science.gov (United States)

    Jung, Hee Joon; Edwards, Dan J.; Kurtz, Richard J.; Yamamoto, Takuya; Wu, Yuan; Odette, G. Robert

    2017-02-01

    An investigation of the influence of helium on damage evolution under neutron irradiation of an 11 at% Al, 19 at% Cr ODS ferritic PM2000 alloy was carried out in the High Flux Isotope Reactor (HFIR) using a novel in situ helium injection (ISHI) technique. Helium was injected into adjacent TEM discs from thermal neutron 58Ni(nth,γ) 59Ni(nth,α) reactions in a thin NiAl layer. The PM2000 undergoes concurrent displacement damage from the high-energy neutrons. The ISHI technique allows direct comparisons of regions with and without high concentrations of helium since only the side coated with the NiAl experiences helium injection. The corresponding microstructural and microchemical evolutions were characterized using both conventional and scanning transmission electron microscopy techniques. The evolutions observed include formation of dislocation loops and associated helium bubbles, precipitation of a variety of phases, amorphization of the Al2YO3 oxides (which also variously contained internal voids), and several manifestations of solute segregation. Notably, high concentrations of helium had a significant effect on many of these diverse phenomena. These results on PM2000 are compared and contrasted to the evolution of so-called nanostructured ferritic alloys (NFA).

  2. Why neutron guides may end up breaking down? Some results on the macroscopic behaviour of alkali-borosilicate glass support plates under neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Boffy, R.; Kreuz, M. [Institut Laue-Langevin, 71 avenue des Martyrs, CS 20156, F-38042 Grenoble Cedex 9 (France); Beaucour, J., E-mail: beaucour@ill.fr [Institut Laue-Langevin, 71 avenue des Martyrs, CS 20156, F-38042 Grenoble Cedex 9 (France); Köster, U. [Institut Laue-Langevin, 71 avenue des Martyrs, CS 20156, F-38042 Grenoble Cedex 9 (France); Bermejo, F.J. [Instituto de Estructura de la Materia, Consejo Superior de Investigaciones Cientificas, Serrano 123, E-20886 Madrid (Spain)

    2015-09-01

    In this paper we report on a first part of a study on the mechanisms leading to brittle fracture in neutron guides made of glass as structural element. Such devices are widely used to deliver thermal and cold neutron beams to experimental lines in most large neutron research facilities. We present results on macroscopic properties of samples of guide glass substrates which are subjected to neutron irradiation at relatively large fluences. The results show a striking dependence of some of the macroscopic properties such as density, shape or surface curvature upon the specific chemical composition of a given glass. The relevance of the present findings for the installation of either replacement guides at the existing facilities or for the deployment of instruments for ongoing projects such as the European Spallation Source is briefly discussed.

  3. Contribution To Degradation Study, Behavior Of Unsaturated Polyester Resin Under Neutron Irradiation

    Science.gov (United States)

    Abellache, D.; Lounis, A.; Taïbi, K.

    2010-01-01

    Applications of unsaturated polyester thermosetting resins are numerous in construction sector, in transport, electric spare parts manufactures, consumer goods, and anticorrosive materials. This survey reports the effect of thermosetting polymer degradation (unsaturated polyester): degradation by neutrons irradiation. In order to evaluate the deterioration of our material, some comparative characterizations have been done between standard samples and damaged ones. Scanning electron microscopy (SEM), ultrasonic scanning, hardness test (Shore D) are the techniques which have been used. The exposure to a neutrons flux is carried out in the column of the nuclear research reactor of Draria (Algiers-Algeria). The energetic profile of the incidental fluxes is constituted of fast neutrons (ΦR = 3.1012n.cm-2.s-1, E = 2 Mev) of thermal neutrons (ΦTH = 1013n.cm-2.s-1; E = 0.025 ev) and epithermal neutrons (Φepi = 7.1011 n.cm-2.s-1; E>4,9 ev). The received dose flow is 0,4 Kgy. We notice only a few scientific investigations can be found in this field. In comparison with the standard sample (no exposed) it is shown that the damage degree is an increasing process with the exposure. Concerning the description of irradiation effects on polymers, we can advance that several reactions are in competition : reticulation, chain break, and oxidation by radical mechanism. In our case the incidental particle of high energy fast neutrons whose energy is greater or equal to 2 Mev, is braked by the target with a nuclear shock during which the incidental particle transmits a part of its energy to an atom. If the energy transfer is sufficient, the nuclear shock permits to drive out an atom of its site the latter will return positioning interstitially, the energy that we used oversteps probably the energy threshold (displacement energy). This fast neutrons collision with target cores proceeds to an indirect ionization by the preliminary creation of excited secondary species that will

  4. Development of Pneumatic Transfer Irradiation Facility (PTS no.1) for Neutron Activation Analysis at HANARO Research Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Y. S.; Moon, J. H.; Kim, S. H.; Sun, G. M.; Baek, S. Y.; Kim, H. R.; Kim, Y. J

    2008-03-15

    A pneumatic transfer system (PTS) is one of the most important facilities used during neutron irradiation of a target material for instrumental neutron activation analysis (INAA) in a research reactor. In particular, a fast pneumatic transfer system is essential for the measurement of a short half-life nuclide and a delayed neutron counting system. The pneumatic transfer system (PTS no.1) involving a manual system and an semiautomatic system were reconstructed with new designs of a functional improvement at the HANARO research reactor in 2006. In this technical report, the conception, design, operation and control of these system (PTS no.1) was described. Also the experimental results and the characteristic parameters measured by a mock-up test, a functional operation test and an irradiation test of these systems, such as the transfer time of irradiation capsule, the different neutron flux, the temperature of the irradiation position with an irradiation time, the radiation dose rate when the rabbit is returned, etc. are reported to provide a user information as well as a reactor's management and safety.

  5. Effects of neutron irradiation on pinning force scaling in state-of-the-art Nb3Sn wires

    CERN Document Server

    Baumgartner, T; Weber, H W; Flükiger, R; Scheuerlein, C; Bottura, L

    2014-01-01

    We present an extensive irradiation study involving five state-of-the-art Nb3Sn wires which were subjected to sequential neutron irradiation up to a fast neutron fluence of 1.6 x 10(22) m(-2) (E > 0.1 MeV). The volume pinning force of short wire samples was assessed in the temperature range from 4.2 to 15 K in applied fields of up to 7 T by means of SQUID magnetometry in the unirradiated state and after each irradiation step. Pinning force scaling computations revealed that the exponents in the pinning force function differ significantly from those expected for pure grain boundary pinning, and that fast neutron irradiation causes a substantial change in the functional dependence of the volume pinning force. A model is presented, which describes the pinning force function of irradiated wires using a two-component ansatz involving a point-pinning contribution stemming from radiation induced pinning centers. The dependence of this point-pinning contribution on fast neutron fluence appears to be a universal funct...

  6. Test results of an ITER relevant FPGA when irradiated with neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Batista, Antonio J. N.; Santos, Bruno; Fernandes, Ana; Goncalves, Bruno [Instituto de Plasmas e Fusao Nuclear, Instituto Superior Tecnico, Universidade de Lisboa, 1049-001 Lisboa, (Portugal); Leong, Carlos; Teixeira, Joao P. [Instituto de Engenharia de Sistemas e Computadores - Investigacao e Desenvolvimento, 1000-029 Lisboa, (Portugal); Ramos, Ana Rita; Santos, Joana P.; Marques, Jose G. [Centro de Ciencias e Tecnologias Nucleares, Instituto Superior Tecnico, Universidade de Lisboa, 2695-066 Bobadela, (Portugal)

    2015-07-01

    The data acquisition and control instrumentation cubicles room of the ITER tokamak will be irradiated with neutrons during the fusion reactor operation. A Virtex-6 FPGA from Xilinx (XC6VLX365T-1FFG1156C) is used on the ATCA-IO-PROCESSOR board, included in the ITER Catalog of I and C products - Fast Controllers. The Virtex-6 is a re-programmable logic device where the configuration is stored in Static RAM (SRAM), functional data stored in dedicated Block RAM (BRAM) and functional state logic in Flip-Flops. Single Event Upsets (SEU) due to the ionizing radiation of neutrons causes soft errors, unintended changes (bit-flips) to the values stored in state elements of the FPGA. The SEU monitoring and soft errors repairing, when possible, were explored in this work. An FPGA built-in Soft Error Mitigation (SEM) controller detects and corrects soft errors in the FPGA configuration memory. Novel SEU sensors with Error Correction Code (ECC) detect and repair the BRAM memories. Proper management of SEU can increase reliability and availability of control instrumentation hardware for nuclear applications. The results of the tests performed using the SEM controller and the BRAM SEU sensors are presented for a Virtex-6 FPGA (XC6VLX240T-1FFG1156C) when irradiated with neutrons from the Portuguese Research Reactor (RPI), a 1 MW nuclear fission reactor operated by IST in the neighborhood of Lisbon. Results show that the proposed SEU mitigation technique is able to repair the majority of the detected SEU errors in the configuration and BRAM memories. (authors)

  7. Correlative Microscopy of alpha' Precipitation in Neutron-Irradiated Fe-Cr-Al Alloys

    Science.gov (United States)

    Briggs, Samuel A.

    Fe-Cr-Al alloys are currently being considered for accident tolerant light water reactor fuel cladding applications due to their superior high temperature oxidation and corrosion resistance compared to Zr-based alloys. However, precipitation of the Cr-rich alpha' phase during exposure to LWR operational environments can result in application-limiting hardening and embrittlement. To study this effect, four Fe-Cr-Al model alloys with compositions between 10-18 at.% Cr and 5.8-9.3 at.% Al have been neutron-irradiated in the High Flux Isotope Reactor at a target temperature of 320°C to nominal damage doses of up to 7 dpa in order to emulate typical LWR exposure conditions. A correlative microscopy approach involving atom probe tomography, small-angle neutron scattering, and scanning transmission electron microscopy coupled with energy dispersive x-ray spectroscopy was employed to study the resulting precipitate microstructure. This approach necessitated the development of various analysis techniques to allow for cross-comparison between experimental techniques, including a novel method for correcting for trajectory aberration artifacts in atom probe data sets through phase density comparison. Successful correlation of results from these techniques allows for the individual limitations of each to be overcome and enables the detailed microstructural information gleaned from highly localized atom probe tomography analyses to be extrapolated to bulk alloy behavior. Precipitation response was found to increase with Cr content, while Al additions appeared to partially destabilized the alpha' phase, resulting in precipitate compositions with reduced Cr content compared to binary Fe-Cr systems. Observed precipitate evolution with radiation dose indicates a diffusion-limited coarsening mechanism that is similar to what is observed in the thermally aged system. This work represents the current state-of-the-art on both techniques for analysis of alpha' precipitate

  8. Influence of Different Moderator Materials on Characteristics of Neutron Fluxes Generated under Irradiation of Lead Target with Proton Beams

    CERN Document Server

    Sosnin, A N; Polanski, A; Petrochenkov, S A; Golovatyuk, V M; Krivopustov, M I; Bamblevski, V P; Westmeier, W; Odoj, R; Brandt, R; Robotham, H; Hashemi-Nezhad, S R; Zamani-Valassiadou, M

    2002-01-01

    Neutron fields generated in extended heavy (Z\\geq 82) targets under irradiation with proton beams at energies in the range of 1 GeV are investigated. Influence of different moderators on the spectra and multiplicities of neutrons escaping the surface of the assembly consisting of a lead target (\\varnothing 8 cm\\times 20 cm or \\varnothing 8cm\\times 50 cm) screened by variable thickness of polyethylene or graphite, respectively, was compared in the present work. It is shown that the effectiveness of graphite as a material used in such assemblies to moderate spallation neutrons down to thermal energies is significantly lower than that of paraffin.

  9. Certification testing at low temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Noss, P.W. [Packaging Technology, Tacoma, WA (United States); Ammerman, D.J. [Sandia National Labs., Albuquerque, NM (United States)

    2004-07-01

    Regulations governing the transport of radioactive materials require that most hypothetical accident condition tests or analyses consider the effects of the environmental temperature that most challenges package performance. For many packages, the most challenging temperature environment is the cold condition (-29 C according to U.S. regulations), primarily because the low temperature causes the highest free drop impact forces due to the higher strength of many energy-absorbing materials at this temperature. If it is decided to perform low temperature testing, it is only necessary that the relevant parts of the package have the required temperature prior to the drop. However, the details of performing a drop at low temperature can have a large influence on testing cost and technical effectiveness. The selection of the test site, the chamber and type of chilling equipment, instrumentation, and even the time of year are all important. Control of seemingly minor details such as the effect on internal pressure, placement of monitoring thermocouples, the thermal time constant of the test article, and icing of equipment are necessary to ensure a successful low temperature test. This paper will discuss these issues and offer suggestions based on recent experience.

  10. Low temperature aluminum soldering analysis

    Energy Technology Data Exchange (ETDEWEB)

    Peterkort, W.G.

    1976-09-01

    The investigation of low temperature aluminum soldering included the collection of spread factor and dihedral angle data for several solder alloys and a study of flux effects on aluminum. Selected solders were subjected to environmental tests and evaluated on the basis of tensile strength, joint resistance, visual appearance, and metallurgical analysis. A production line method for determining adequate flux removal was developed.

  11. Low-temperature magnetic refrigerator

    Science.gov (United States)

    Barclay, John A.

    1985-01-01

    The disclosure is directed to a low temperature 4 to 20 K. refrigeration apparatus and method utilizing a ring of magnetic material moving through a magnetic field. Heat exchange is accomplished in and out of the magnetic field to appropriately utilize the device to execute Carnot and Stirling cycles.

  12. High-dose neutron irradiation of Hi-Nicalon Type S silicon carbide composites. Part 2: Mechanical and physical properties

    Energy Technology Data Exchange (ETDEWEB)

    Katoh, Yutai, E-mail: katohy@ornl.gov [Oak Ridge National Laboratory, Oak Ridge, TN (United States); Nozawa, Takashi [Japan Atomic Energy Agency, Rokkasho, Aomori-ken (Japan); Shih, Chunghao [Oak Ridge National Laboratory, Oak Ridge, TN (United States); Ozawa, Kazumi [Japan Atomic Energy Agency, Rokkasho, Aomori-ken (Japan); Koyanagi, Takaaki; Porter, Wally; Snead, Lance L. [Oak Ridge National Laboratory, Oak Ridge, TN (United States)

    2015-07-15

    Nuclear-grade silicon carbide (SiC) composite material was examined for mechanical and thermophysical properties following high-dose neutron irradiation in the High Flux Isotope Reactor at a temperature range of 573–1073 K. The material was chemical vapor-infiltrated SiC-matrix composite with a two-dimensional satin weave Hi-Nicalon Type S SiC fiber reinforcement and a multilayered pyrocarbon/SiC interphase. Moderate (1073 K) to very severe (573 K) degradation in mechanical properties was found after irradiation to >70 dpa, whereas no evidence was found for progressive evolution in swelling and thermal conductivity. The swelling was found to recover upon annealing beyond the irradiation temperature, indicating the irradiation temperature, but only to a limited extent. The observed strength degradation is attributed primarily to fiber damage for all irradiation temperatures, particularly a combination of severe fiber degradation and likely interphase damage at relatively low irradiation temperatures.

  13. Clinical Report on Californium-252 Neutron Intraluminal Brachytherapy Combined with External Irradiation for Cervical Carcinoma Treatment

    Institute of Scientific and Technical Information of China (English)

    Huanyu Zhao; Keming Wang; Jian Sun; Xin Geng; Weiming Zhang

    2006-01-01

    OBJECTIVE To observe the curative effects and complications of californium-252 (252Cf) neutron intraluminal brachytherapy (IBT) combined with external irradiation (El) for treatment of cervical carcinoma.METHODS From December 2000 to December 2004, 128 cases of cervical carcinoma staged into ⅡA~ⅢB according to the International Federation of Gynecology and Obstetrics (FIGO) standards were treated with 252Cf neutron IBT using 8~10 Gy per fraction, once a week. The total dose at reference A point was 36~40 Gy in 4~5 fractions. From the second day after 252Cf neutron IBT treatment, the whole pelvic cavity was treated with 60Co γ-ray El, applying 2 Gy per fraction, 4 times per week. After 20~25 Gy of El, the center of the whole pelvic field was blocked with 4 cm of lead in width. The total dose of El was 45~50 Gy.RESULTS The short-term therapeutic effects were CR 95.3% and PR 4.7%. The 3 and 5-year local control rates were 93.5% and 87.9%. The overall 3-year survival rate was 87.5% and for Stages Ⅱ and Ⅲ , 90.9%and 81.5% respectively; the overall 5-year survival rate was 70% and for Stages Ⅱ and Ⅲ, 76.2% and 61% respectively. The rate of radiation complications was 4.7% for radiation cystitis, 7.8% for radiation proctitis, 6.3%for vagina contracture and adhesion and 5.5% for protracted radiation proctitis.CONCLUSION An combination of 252Cf neutron IBT with El for treatment of cervical carcinoma can be well-tolerated by cervical carcinoma patients. The rate of local tumor control is high and radiation complications are few.

  14. Development of Pneumatic Transfer Irradiation Facility (PTS no.3) for Neutron Activation Analysis at HANARO Research Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Y. S.; Moon, J. H.; Kim, S. H.; Sun, G. M.; Baek, S. Y.; Kim, H. R.; Kim, Y. J

    2008-04-15

    A pneumatic transfer system (PTS) is one of the most important facilities used during neutron irradiation of a target material for instrumental neutron activation analysis (INAA) in a research reactor. In particular, a fast pneumatic transfer system is essential for the measurement of a short half-life nuclide. The pneumatic transfer irradiation system (PTS no.3) involving a manual system and an semi-automatic system were reconstructed with new designs of a functional improvement at the HANARO research reactor and NAA laboratory of RI building in 2006. In this technical report, the design, operation and control of these system (PTS no.3) was described. Also the experimental results and the characteristic parameters measured from a functional operation test and an irradiation test of these systems, such as the transfer time of irradiation capsule, the different neutron flux, the temperature of the irradiation position with an irradiation time, the radiation dose rate when the rabbit is returned, etc. are reported to provide a user information as well as a reactor's management and safety.

  15. Improvement of switching speed of a 600-V nonpunch through insulated gate bipolar transistor using fast neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Baek, Ha Ni; Sun, Gwang Min; Kim, Ji Suck; Hoang, Sy Minh Tuan; Jin, Mi Eun; Ahn, Sung Ho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2017-02-15

    Fast neutron irradiation was used to improve the switching speed of a 600-V nonpunch-through insulated gate bipolar transistor. Fast neutron irradiation was carried out at 30-MeV energy in doses of 1 × 10{sup 8} n/cm{sup 2}, 1 × 10{sup 9} n/cm{sup 2}, 1 × 10{sup 10} n/cm{sup 2}, and 1 × 10{sup 11} n/cm{sup 2}. Electrical characteristics such as current–voltage, forward on-state voltage drop, and switching speed of the device were analyzed and compared with those prior to irradiation. The on-state voltage drop of the initial devices prior to irradiation was 2.08 V, which increased to 2.10 V, 2.20 V, 2.3 V, and 2.4 V, respectively, depending on the irradiation dose. This effect arises because of the lattice defects generated by the fast neutrons. In particular, the turnoff delay time was reduced to 92 nanoseconds, 45% of that prior to irradiation, which means there is a substantial improvement in the switching speed of the device.

  16. Tritium removal from various lithium aluminates irradiated by fast and thermal neutrons (COMPLIMENT experiment)

    Science.gov (United States)

    Alvani, C.; Carconi, P. L.; Casadio, S.; Moauro, A.

    1994-02-01

    Within the frame of the COMPLIMENT experiment, γ-LiAlO 2 specimens with different microstructures (grain size distributions) were tested in the same environmental conditions to compare the effects caused by 6Li(n, α)T reaction and by fast neutron scattering, the damaging dose being held at about the same level (1.6-1.8 dpa). The tritium retention times were obtained by the tritium removal of isothermal annealing under He + 0.1% H 2 sweeping gas. In spite of the different Li burnups (2.5% and 0.25%) and the residual tritium concentrations which were found in the irradiated specimens (4.3 Ci/g and 0.09 Ci/g, respectively, for specimens held at 450°C during the irradiations), the kinetics of tritium removal was not found to be discriminated by the two different irradiations. Moreover, the results were found to agree with those previously obtained by the "in-situ" TEQUILA experiment, performed on the same type of Li ceramics. Hence, the apparent first order desorption mechanism has been confirmed to control the kinetics of tritium removal from the porous fine grain γ-LiAlO 2 ceramics.

  17. EFFECTS OF IRRADIATION ON THERMAL CONDUCTIVITY OF ALLOY 690 AT LOW NEUTRON FLUENCE

    Directory of Open Access Journals (Sweden)

    WOO SEOG RYU

    2013-04-01

    Full Text Available Alloy 690 has been selected as a steam generator tubing material for SMART owing to a near immunity to primary water stress corrosion cracking. The steam generators of SMART are faced with a neutron flux due to the integrated arrangement inside a reactor vessel, and thus it is important to know the irradiation effects of the thermal conductivity of Alloy 690. Alloy 690 was irradiated at HANARO to fluences of (0.7−28 × 1019n/cm2 (E>0.1MeV at 250°C, and its thermal conductivity was measured using the laser-flash equipment in the IMEF. The thermal conductivity of Alloy 690 was dependent on temperature, and it was a good fit to the Smith-Palmer equation, which modified the Wiedemann-Franz law. The irradiation at 250°C did not degrade the thermal conductivity of Alloy 690, and even showed a small increase (1% at fluences of (0.7∼28 × 1019n/cm2 (E>0.1MeV.

  18. Ion, X-ray, UV and Neutron Microbeam Systems for Cell Irradiation

    Science.gov (United States)

    Bigelow, A.W.; Randers-Pehrson, G.; Garty, G.; Geard, C.R.; Xu, Y.; Harken, A.D.; Johnson, G. W.; Brenner, D.J.

    2012-01-01

    The array of microbeam cell-irradiation systems, available to users at the Radiological Research Accelerator Facility (RARAF), Center for Radiological Research, Columbia University, is expanding. The HVE 5MV Singletron particle accelerator at the facility provides particles to two focused ion microbeam lines: the sub-micron microbeam II and the permanent magnetic microbeam (PMM). Both the electrostatic quadrupole lenses on the microbeam II system and the magnetic quadrupole lenses on the PMM system are arranged as compound lenses consisting of two quadrupole triplets with “Russian” symmetry. Also, the RARAF accelerator is a source for a proton-induced x-ray microbeam (undergoing testing) and is projected to supply protons to a neutron microbeam based on the 7Li(p, n)7Be nuclear reaction (under development). Leveraging from the multiphoton microscope technology integrated within the microbeam II endstation, a UV microspot irradiator – based on multiphoton excitation – is available for facility users. Highlights from radiation-biology demonstrations on single living mammalian cells are included in this review of microbeam systems for cell irradiation at RARAF. PMID:23420504

  19. Tritium removal from various lithium aluminates irradiated by fast and thermal neutrons (COMPLIMENT experiment)

    Energy Technology Data Exchange (ETDEWEB)

    Alvani, C. (ENEA CRE Casaccia, INN/NUMA, Rome (Italy)); Carconi, P.L. (ENEA CRE Casaccia, INN/NUMA, Rome (Italy)); Casadio, S. (ENEA CRE Casaccia, INN/NUMA, Rome (Italy)); Moauro, A. (ENEA CRE Casaccia, INN/NUMA, Rome (Italy))

    1994-02-01

    Within the frame of the COMPLIMENT experiment, [gamma]-LiAlO[sub 2] specimens with different microstructures (grain size distributions) were tested in the same environmental conditions to compare the effects caused by [sup 6]Li(n, [alpha])T reaction and by fast neutron scattering, the damaging dose being held at about the same level (1.6-1.8 dpa). The tritium retention times were obtained by the tritium removal of isothermal annealing under He + 0.1% H[sub 2] sweeping gas. In spite of the different Li burnups (2.5% and 0.25%) and the residual tritium concentrations which were found in the irradiated specimens (4.3 Ci/g and 0.09 Ci/g, respectively, for specimens held at 450 C during the irradiations), the kinetics of tritium removal was not found to be discriminated by the two different irradiations. Moreover, the results were found to agree with those previously obtained by the ''in-situ'' TEQUILA experiment, performed on the same type of Li ceramics. Hence, the apparent first order desorption mechanism has been confirmed to control the kinetics of tritium removal from the porous fine grain [gamma]-LiAlO[sub 2] ceramics. (orig.)

  20. Effect of acute whole-body neutron gamma irradiation on the dopamine neuronal uptake-sites; Effets d`une irradiation globale aigue a preponderance neutron sur le transporteur de capture neuronale de la dopamine

    Energy Technology Data Exchange (ETDEWEB)

    Martin, C.; Mahfoudi, H.; Lambert, F.; Burckhart, M.F.; Fatome, M. [Centre de Recherches du Service de Sante des Armees, La Tronche, 38 - Grenoble (France)

    1997-12-31

    The effects of (neutron-gamma) irradiation on the dopamine uptake sites distribution were investigated, using quantitative autoradiography. Brain ares examined are striatum, lateral septum, substantia nigra, gyrus dentatus, ventral tegmental area, interfascicular nu and antero-ventral thalamic nu. Three hours after exposure at the dose of 4 Gy, a decrease (- 33 %) of dopamine uptake sites was observed in the gyrus dentatus. (authors)

  1. Evaluation of neutron flux parameters in irradiation sites of research reactor using the Westcott-formalism for the k0 neutron activation analysis method

    Science.gov (United States)

    Kasban, H.; Hamid, Ashraf

    2015-12-01

    Instrumental Neutron Activation Analysis using k0 (k0-INAA) method has been used to determine a number of elements in sediment samples collected from El-Manzala Lake in Egypt. k0-INAA according to Westcott's formalism has been implemented using the complete irradiation kit of the fast pneumatic rabbit and some selected manually loaded irradiation sites for short and long irradiation at Egypt Second Research Reactor (ETRR-2). Zr-Au and Co sets as neutron flux monitors are used to determine the neutron flux parameters (f and α) in each irradiation sites. Two reference materials IAEA Soil-7 samples have been inserted and implemented for data validation and an internal monostandard multi monitor used (k0 based IM-NAA). It was given a good agreement between the experimental analyzed values and that obtained of the certified values. The major and trace elements in the sediment samples have been evaluated with the use of Co as an internal and Au as an external monostandard comparators. The concentrations of the elements (Cr, Mn and Zn) in the sediment samples of the present work are discussed regarding to those obtained from other sites.

  2. Design and Demonstration of a Material-Plasma Exposure Target Station for Neutron Irradiated Samples

    Energy Technology Data Exchange (ETDEWEB)

    Rapp, Juergen [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Aaron, A. M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bell, Gary L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Burgess, Thomas W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ellis, Ronald James [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Giuliano, D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Howard, R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kiggans, James O. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Lessard, Timothy L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ohriner, Evan Keith [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Perkins, Dale E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Varma, Venugopal Koikal [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-10-20

    Fusion energy is the most promising energy source for the future, and one of the most important problems to be solved progressing to a commercial fusion reactor is the identification of plasma-facing materials compatible with the extreme conditions in the fusion reactor environment. The development of plasma–material interaction (PMI) science and the technology of plasma-facing components are key elements in the development of the next step fusion device in the United States, the so-called Fusion Nuclear Science Facility (FNSF). All of these PMI issues and the uncertain impact of the 14-MeV neutron irradiation have been identified in numerous expert panel reports to the fusion community. The 2007 Greenwald report classifies reactor plasma-facing materials (PFCs) and materials as the only Tier 1 issues, requiring a “. . . major extrapolation from the current state of knowledge, need for qualitative improvements and substantial development for both the short and long term.” The Greenwald report goes on to list 19 gaps in understanding and performance related to the plasma–material interface for the technology facilities needed for DEMO-oriented R&D and DEMO itself. Of the 15 major gaps, six (G7, G9, G10, G12, G13) can possibly be addressed with ORNL’s proposal of an advanced Material Plasma Exposure eXperiment. Establishing this mid-scale plasma materials test facility at ORNL is a key element in ORNL’s strategy to secure a leadership role for decades of fusion R&D. That is to say, our end goal is to bring the “signature facility” FNSF home to ORNL. This project is related to the pre-conceptual design of an innovative target station for a future Material–Plasma Exposure eXperiment (MPEX). The target station will be designed to expose candidate fusion reactor plasma-facing materials and components (PFMs and PFCs) to conditions anticipated in fusion reactors, where PFCs will be exposed to dense high-temperature hydrogen plasmas providing steady

  3. The effect of neutron irradiation defects on electrical resistivity in FZ-silicon samples irradiated at Es-Salam research reactor

    Energy Technology Data Exchange (ETDEWEB)

    Abbaci, M. [Centre de Recherche Nucleaire de Birine, BP 180, Ain Oussera W. Djelfa 17200 (Algeria)]. E-mail: abbacim@yahoo.fr; Meglali, O. [Centre de Recherche Nucleaire de Birine, BP 180, Ain Oussera W. Djelfa 17200 (Algeria); Saim, A. [Centre de Recherche Nucleaire de Birine, BP 180, Ain Oussera W. Djelfa 17200 (Algeria); Osmani, N. [Centre de Recherche Nucleaire de Birine, BP 180, Ain Oussera W. Djelfa 17200 (Algeria); Doghmane, N. [Departement d' Electronique, Faculte des Sciences de l' Ingenieur, Universite Badji Mokhtar, BP 12, Annaba 23000 (Algeria)

    2006-09-15

    This paper reports the effect of neutron irradiation defects on electrical properties of n-type FZ-silicon via the measurements of electrical resistivity. For this purpose, FZ-silicon single crystal was irradiated with neutron fluences ranging between 1.54 x 10{sup 16} and 2.5 x 10{sup 18} cm{sup -2}. The samples irradiated at F {sub 1} = 1.54 x 10{sup 16} cm{sup -2}, F {sub 2} = 7.43 x 10{sup 17} cm{sup -2} and F {sub 3} = 2.5 x 10{sup 18} cm{sup -2} were isochronally annealed from room temperature up to 750 {sup o}C. It is found that, for fluences ranging respectively from 1.54 x 10{sup 16} cm{sup -2} to 1.23 x 10{sup 17} cm{sup -2} (stage I) and from 3.09 x 10{sup 17} cm{sup -2} to 2.5 x 10{sup 18} cm{sup -2} (stage II) the resistivity is linearly related to the neutron fluence with two different slopes. The annealing temperature dependence on the electrical resistivity fits well the relation{rho} {sub 0} exp(-CT), where C is a constant depending on the neutron fluence and {rho} {sub 0} is approximately equal to the resistivity after irradiation. For annealing temperatures higher than 550 {sup o}C, we have found that the resistivity is a decreasing function with respect to the neutron fluence and the transmutation-doped phosphorus atoms become electrically active.

  4. Evaluation of neutron irradiation embrittlement in the Korean reactor pressure vessel steels(I) (1st progress report)

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Jun Hwa; Lee, Bong Sang; Park, Duck Gun; Byun, Tak Sang; Kim, Joo Hag; Oh, Yong Jun; Yoon, Ji Hyun; Chi, Sei Hwan; Kuk, Il Hyun [Korea Atomic Energy Research Institute, Taejon (Korea)

    1998-10-01

    The SA508-3 reactor pressure vessel materials degrade due to the application at high temperature, high pressure, and neutron irradiation. In the present study it is planned to examine the effects of neutron irradiation on the properties for assessing the integrity of domestic reactors. The key tests are the Charpy impact test, tensile test, static and dynamic fracture toughness test, J-R test. The additional tests for obtaining basic material properties, such as micro-hardness, microstructural properties, small punch energy etc., are also performed. The irradiation tests are being performed at HANARO of KAERI through the instrumented capsules designed by KAERI and the post-irradiation tests are being performed at IMEF(Irradiated Material Evaluation Facility) of material (UCN-4), Si+Al (YGN-5), UCN-4 weld metal, and UCN-4 HAZ. In the irradiation test the temperature should be controlled in the range of 290 {+-} 10 deg C and the test materials would be irradiated to 2 to 3 neutron fluence levels including the end-of-life fluence. The status of performing this project is that (1) the key data on mechanical properties, mainly related to the fracture toughness, of the unirradiated materials have been obtained, (2) the irradiation of the 1st instrumented capsule, a preliminary test capsule containing miniature specimens, has been completed and is being stored for testing in IMEF, and (3) the 2nd instrumented capsule is being manufactured and will be irradiated in the beginning or 1999. This report includes mainly the experimental methods and results. The status of the design and manufacturing of the instrumented capsules and specimens was also briefly described. (author). 13 refs., 15 figs., 10 tabs.

  5. Low Temperature Spin Structure of Gadolinium Titanate

    Science.gov (United States)

    Javanparast, Behnam; McClarty, Paul; Gingras, Michel

    2012-02-01

    Many rare earth pyrochlore oxides exhibit exotic spin configurations at low temperatures due to frustration. The nearest neighbor coupling between spins on the corner-sharing tetrahedral network generate geometrical magnetic frustration. Among these materials, gadolinium titanate (Gd2Ti2O7) is of particular interest. Its low temperature ordered phases are not yet understood theoretically. Bulk thermal measurements such as specific heat and magnetic susceptibility measurements find two phase transitions in zero external field, in agreement with simple mean field calculations. However, recent neutron scattering experiments suggest a so-called 4-k spin structure for intermediate phase and a so called canted 4-k structure for lower temperature phase that does not agree with either mean-field theory or Monte Carlo simulation which find the 1-k state and Palmer-Chalker state respectively as the lowest free energy configuration for those phases. In our work, we study the 4-k structure in detail and present a new phase diagram for dipolar Heisenberg spins on a pyrochlore lattice, certain portions of which describe gadolinium titanate.

  6. Life span, testis damage and immune cell populations of spleen in C57BL mice with neutron irradiation by lying flat pose

    Energy Technology Data Exchange (ETDEWEB)

    Chun, Ki Jung; kim, Myung Sup; Kyung, Yoo Bo [KAERI, Taejon (Korea)

    2003-10-01

    This study deals with the biological effects of black mouse (C57BL) irradiated with neutron irradiation by using Boron Neutron Capture Therapy facility in HANARO reactor. These include mortality, body wt., hair color, testis volume, sperm count and immune cell populations in mouse spleen after 80 days later by thermal neutron irradiation. Six week old C57BL male mice were irradiated with neutron irradiation for 1 hr or 2 hrs (flux : 1.036739E +09). These irradiat ion doses estimated 15Gy and 30Gy, respectively. Survival days and hair color in mice was checked. On day 80 after irradiation, testis were taken for volume and sperm count. Also spleen was taken for FACS and spleen cells were isolatd and discarded RBC by treating with lysising solution. These cells were placed on ice and immunofluorescence staining was performed. Phycoerythrin (PE )-anti-CD3e, fluorescein isothiocyanate (FITC)-anti-CD4, and FITC-anti-CD8 were added, then the immunostaining cells were incubated on ice for 40 min. The resulting cells were washed with a PBS buffer 3 times and analyzed using a Flow cytometer. All experimental animals survived over 90 days but in case of 30 Gy neutron irradiation, black mice hair were changed white color on the center of the back. Neutron irradiation of black mice show similar in damage of spleen immune cells by subpopulation of T helper and T cytotoxic cells compared to the control non - irradiated group. These results show that treatment of neutron irradiation without boron compounds for 2 hrs in mice can survive over 90 days with hair color change from black to white. Damaged spleen cells recover after long time by irradiation but testis volume and no. of sperm are not recover compared to the normal group in response to neutron irradiation.

  7. Radiation damage induced in Al{sub 2}O{sub 3} single crystal sequentially irradiated with reactor neutrons and 90 MeV Xe ions

    Energy Technology Data Exchange (ETDEWEB)

    Zirour, H. [Faculty of Physics, USTHB, BP. 32, El-Alia, Bab-Ezzouar, Algiers (Algeria); Izerrouken, M., E-mail: izerrouken@yahoo.com [Centre de Recherche Nucléaire de Draria, BP. 43, Sebbala, Draria, Algiers (Algeria); Sari, A. [Centre de Recherche Nucléaire de Berine, BP. 108, Ain-Oussara, Djelfa (Algeria)

    2016-06-15

    The present investigation reports the effect of 90 MeV Xe ion irradiation on neutron irradiated Al{sub 2}O{sub 3} single crystals. Three irradiation experiments were performed, with neutrons only, 90 MeV Xe ions only and with neutrons followed by 90 MeV Xe ions. Neutron and 90 MeV Xe ion irradiations were performed at NUR research reactor, Algiers, Algeria and at GANIL accelerator, Caen, France respectively. After irradiation, the radiation damage was investigated by Raman spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), optical absorption measurements, and X-ray diffraction (XRD) techniques. Raman technique revealed that the concentration of the defects formed in Al{sub 2}O{sub 3} samples subsequently irradiated with neutrons and 90 MeV Xe ions is lower than that formed in Al{sub 2}O{sub 3} samples which were irradiated only with neutrons. This reveals the occurrence of ionization-induced recovery of the neutron damage. Furthermore, as revealed by XRD analysis, a new peak is appeared at about 2θ = 38.03° after irradiation at high fluence (>3 × 10{sup 13} Xe/cm{sup 2}). It can be assigned to the formation of new lattice plane.

  8. Development of indigenous insulation material for superconducting magnets and study of its characteristics under influence of intense neutron irradiation

    Science.gov (United States)

    Sharma, Rajiv; Tanna, V. L.; Rao, C. V. S.; Abhangi, Mitul; Vala, Sudhirsinh; Sundaravel; Varatharajan, S.; Sivakumar, S.; Sasi, K.; Pradhan, S.

    2017-02-01

    Epoxy based glass fiber reinforced composites are the main insulation system for the superconducting magnets of fusion machines. 14MeV neutrons are generated during the DT fusion process, however the energy spectra and flux gets modified to a great extent when they reach the superconducting magnets. Mechanical properties of the GFRP insulation material is reported to degrade up to 30%. As a part of R & D activity, a joint collaboration with IGCAR, Kalpakkam has been established. The indigenous insulation material is subjected to fast neutron fluence of 1014 - 1019 n/m2 (E>0.1 MeV) in FBTR and KAMINI Reactor, India. TRIM software has been used to simulate similar kind of damage produced by neutrons by ion irradiation with 5 MeV Al ions and 3 MeV protons. Fluence of the ions was adjusted to get the same dpa. We present the test experiment of neutron irradiation of the composite material (E-glass, S-glass fiber boron free and DGEBA epoxy). The test results of tensile, inter laminar shear and electrical breakdown strength as per ASTM standards, assessment of micro-structure surface degradation before and after irradiation will be presented. MCNP simulations are carried out for neutron flux, dose and damages produced in the insulation material.

  9. Low Temperature Emissivity Measurement System

    Directory of Open Access Journals (Sweden)

    Jignesh A. Patel

    2014-05-01

    Full Text Available The emissivity of a material is the relative ability of its surface to emit energy by radiation. It is the ratio of energy radiated by a particular material to energy radiated by a black body at the same temperature. Knowledge about the low temperature emissivity of materials and coatings can be essential to the design of fusion cryoplants and in the thermal modeling for space satellite missions. The emittance of materials at cryogenics temperatures often cannot be predicted from room temperature data, but for computing radiative loads and infrared backgrounds this cryogenic data is often required. Measurement of the cryogenic emissivity of a highly reflective surface is a significant challenge: little thermal power is radiated from the sample, and the background radiation. However some researchers have measured emissivity at various low temperature ranges. Present work reports, the various emissivity measurement setup and their considerations.

  10. Ionizing/displacement synergistic effects induced by gamma and neutron irradiation in gate-controlled lateral PNP bipolar transistors

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Chenhui, E-mail: wangchenhui@nint.ac.cn [State Key Laboratory of Intense Pulsed Irradiation Simulation and Effect, Northwest Institute of Nuclear Technology, P.O. Box 69-10, Xi’an 710024 (China); Chen, Wei; Yao, Zhibin; Jin, Xiaoming; Liu, Yan; Yang, Shanchao [State Key Laboratory of Intense Pulsed Irradiation Simulation and Effect, Northwest Institute of Nuclear Technology, P.O. Box 69-10, Xi’an 710024 (China); Wang, Zhikuan [State Key Laboratory of Analog Integrated Circuit, Chongqing 400060 (China)

    2016-09-21

    A kind of gate-controlled lateral PNP bipolar transistor has been specially designed to do experimental validations and studies on the ionizing/displacement synergistic effects in the lateral PNP bipolar transistor. The individual and mixed irradiation experiments of gamma rays and neutrons are accomplished on the transistors. The common emitter current gain, gate sweep characteristics and sub-threshold sweep characteristics are measured after each exposure. The results indicate that under the sequential irradiation of gamma rays and neutrons, the response of the gate-controlled lateral PNP bipolar transistor does exhibit ionizing/displacement synergistic effects and base current degradation is more severe than the simple artificial sum of those under the individual gamma and neutron irradiation. Enough attention should be paid to this phenomenon in radiation damage evaluation. - Highlights: • A kind of gate-controlled lateral PNP bipolar transistor has been specially designed to facilitate the analysis of ionizing/displacement synergistic effects induced by the mixed irradiation of gamma and neutron. • The difference between ionizing/displacement synergistic effects and the simple sum of TID and displacement effects is analyzed. • The physical mechanisms of synergistic effects are explained.

  11. Inverse magnetocaloric effect in Ce(Fe0.96Ru0.04)2: Effect of fast neutron irradiation

    Science.gov (United States)

    Dube, V.; Mishra, P. K.; Rajarajan, A. K.; Prajapat, C. L.; Sastry, P. U.; Thakare, S. V.; Singh, M. R.; Ravikumar, G.

    2013-02-01

    We have shown the effect of fast neutron irradiation on the magnetic phase transition and magnetocaloric effect (MCE) in a doped Ce(Fe0.96Ru0.04)2, intermettalic. We show that this leads to suppression of MCE and a to a disordered ferromagnetic phase.

  12. Sustained Low Temperature NOx Reduction

    Energy Technology Data Exchange (ETDEWEB)

    Zha, Yuhui

    2017-04-05

    Increasing regulatory, environmental, and customer pressure in recent years led to substantial improvements in the fuel efficiency of diesel engines, including the remarkable breakthroughs demonstrated through the Super Truck program supported by the U.S. Department of Energy (DOE). On the other hand, these improvements have translated into a reduction of exhaust gas temperatures, thus further complicating the task of controlling NOx emissions, especially in low power duty cycles. The need for improved NOx conversion over these low temperature duty cycles is also observed as requirements tighten with in-use emissions testing. Sustained NOx reduction at low temperatures, especially in the 150-200oC range, shares some similarities with the more commonly discussed cold-start challenge, however poses a number of additional and distinct technical problems. In this project we set a bold target of achieving and maintaining a 90% NOx conversion at the SCR catalyst inlet temperature of 150oC. The project is intended to push the boundaries of the existing technologies, while staying within the realm of realistic future practical implementation. In order to meet the resulting challenges at the levels of catalyst fundamentals, system components, and system integration, Cummins has partnered with the DOE, Johnson Matthey, and Pacific Northwest National Lab and initiated the Sustained Low-Temperature NOx Reduction program at the beginning of 2015. Through this collaboration, we are exploring catalyst formulations and catalyst architectures with enhanced catalytic activity at 150°C; opportunities to approach the desirable ratio of NO and NO2 in the SCR feed gas; options for robust low-temperature reductant delivery; and the requirements for overall system integration. The program is expected to deliver an on-engine demonstration of the technical solution and an assessment of its commercial potential. In the SAE meeting, we will share the initial performance data on engine to

  13. Differences in TLD 600 and TLD 700 glow curves derived from distict mixed gamma/neutron field irradiations

    Energy Technology Data Exchange (ETDEWEB)

    Cavalieri, Tassio A.; Castro, Vinicius A.; Siqueira, Paulo T.D., E-mail: tassio.cavalieri@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Engenharia Nuclear

    2013-07-01

    In Neutron Capture Therapy, a thermal neutron beam shall impinge on a specific nuclide, such as {sup 10}B, to promote a nuclear reaction which releases the useful therapeutic energy. A nuclear reactor is usually used as the neutron source, and therefore field contaminants such as gamma and high energy neutrons are also present in the field. However, mixed field dosimetry still stands as a challenge in some cases, due to the difficulty to experimentally discriminate the dose from each field component. For the mixed field dosimetry, the International Commission on Radiation end Units (ICRU) recommends the use of detector pairs with different responses for each beam component. The TLD 600/700 pair meets this need, because these LiF detectors have different Li isotopes concentration, with distinct thermal neutron responses because {sup 6}Li presents a much higher neutron capture cross section than does {sup 7}Li for low energy neutrons. TLD 600 is {sup 6}Li enriched while TLD 700 is {sup 7}Li enriched. However, depending on the neutron spectrum presented in the mixed field, TLD 700 response to thermal neutrons cannot be disregarded. This work aims to study the difference in TLD 600 and TLD 700 glow curves when these TLDs are submitted to mixed fields of different energy spectra and components balance. The TLDs were irradiated in a pure gamma source, and in mixed fields from an AmBe sealed source and from the IPEN/MB-01 reactor. These TLDs were read and had their two main dosimetric regions analyzed to observe the differences in the glow curves of these TLDs in each irradiation. Field components discrimination was achieved through Monte Carlo simulations run with MCNP radiation transport code. (author)

  14. Characterization of neutron flux spectra in the irradiation sites of a 37 GBq {sup 241}Am-Be isotopic source

    Energy Technology Data Exchange (ETDEWEB)

    Yücel, Haluk [Ankara University, Institute of Nuclear Sciences, 06100 Tandogan, Ankara (Turkey); Budak, Mustafa Guray, E-mail: mbudak@gazi.edu.tr [Gazi University, Gazi Education Faculty, 06500 Teknikokullar, Ankara (Turkey); Karadag, Mustafa [Gazi University, Gazi Education Faculty, 06500 Teknikokullar, Ankara (Turkey); Yüksel, Alptuğ Özer [Ankara University, Institute of Nuclear Sciences, 06100 Tandogan, Ankara (Turkey)

    2014-11-01

    Highlights: • An irradiation unit was installed using a 37 GBq {sup 241}Am-Be neutron source. • The source neutrons moderated by using both water and paraffin. • Irradiation unit was shielded by boron oxide and lead against neutrons and gammas. • There are two sites for irradiations, one of them has a pneumatic transfer system. • Cadmium ratio method was used for irradiation site characterization. - Abstract: For the applicability of instrumental neutron activation analysis (NAA) technique, an irradiation unit with a 37 GBq {sup 241}Am-Be neutron source was installed at Institute of Nuclear Sciences of Ankara University. Design and configuration properties of the irradiation unit are described. It has two different sample irradiation positions, one is called site #1 having a pneumatic sample transfer system and the other is site #2 having a location for manual use. In order to characterize neutron flux spectra in the irradiation sites, the measurement results were obtained for thermal (φ{sub th}) and epithermal neutron fluxes (φ{sub epi}), thermal to epithermal flux ratio (f) and epithermal spectrum shaping factors (α) by employing cadmium ratios of gold (Au) and molybdenum (Mo) monitors. The activities produced in these foils were measured by using a p-type, 44.8% relative efficiency HPGe well detector. For the measured γ-rays, self-absorption and true coincidence summing effects were taken into account. Additionally, thermal neutron self-shielding and resonance neutron self-shielding effects were taken into account in the measured results. For characterization of site #1, the required parameters were found to be φ{sub th} = (2.11 ± 0.05) × 10{sup 3} n cm{sup −2} s{sup −1}, φ{sub epi} = (3.32 ± 0.17) × 10{sup 1} n cm{sup −2} s{sup −1}, f = 63.6 ± 1.5, α = 0.045 ± 0.009, respectively. Similarly, those parameters were measured in site #2 as φ{sub th} = (1.49 ± 0.04) × 10{sup 3} n cm{sup −2} s{sup −1}, φ{sub epi} = (2.93 ± 0

  15. Atom Probe Tomography Characterization of the Solute Distributions in a Neutron-Irradiated and Annealed Pressure Vessel Steel Weld

    Energy Technology Data Exchange (ETDEWEB)

    Miller, M.K.

    2001-01-30

    A combined atom probe tomography and atom probe field ion microscopy study has been performed on a submerged arc weld irradiated to high fluence in the Heavy-Section Steel irradiation (HSSI) fifth irradiation series (Weld 73W). The composition of this weld is Fe - 0.27 at. % Cu, 1.58% Mn, 0.57% Ni, 0.34% MO, 0.27% Cr, 0.58% Si, 0.003% V, 0.45% C, 0.009% P, and 0.009% S. The material was examined after five conditions: after a typical stress relief treatment of 40 h at 607 C, after neutron irradiation to a fluence of 2 x 10{sup 23} n m{sup {minus}2} (E > 1 MeV), and after irradiation and isothermal anneals of 0.5, 1, and 168 h at 454 C. This report describes the matrix composition and the size, composition, and number density of the ultrafine copper-enriched precipitates that formed under neutron irradiation and the change in these parameters with post-irradiation annealing treatments.

  16. Time development and flux dependence of neutron-irradiation induced defects in silicon pad detectors

    CERN Document Server

    Zontar, D; Kramberger, G; Mikuz, M

    1999-01-01

    1x1 cm sup 2 silicon pad p sup + -n-n sup + detectors were irradiated with fast neutrons from the TRIGA research reactor in Ljubljana to fluences from 5x10 sup 1 sup 3 to 10 sup 1 sup 4 n/cm sup 2. The observed time development of annealing of the full-depletion voltage (FDV) could be fitted by a constant and two exponentials. The characteristic time of the fast component is 4 h, independent of temperature in the interval 0-15 deg. C. A comparison of MESA and planar pad detectors shows a 20-30% lower FDV for the MESA. A search for a flux dependence of the radiation damage was performed in the range from 2x10 sup 8 to 5x10 sup 1 sup 5 n/cm sup 2 s and no systematic differences were observed.

  17. Synergies Between ' and Cavity Formation in HT-9 Following High Dose Neutron Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Field, Kevin G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Parish, Chad M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Saleh, Tarik A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Eftink, Benjamin P. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-06-01

    Candidate cladding materials for advanced nuclear power reactors including fast reactor designs require materials capable of withstanding high dose neutron irradiation at elevated temperatures. One candidate material, HT-9, through various research programs have demonstrated the ability to withstand significant swelling and other radiation-induced degradation mechanisms in the high dose regime (>50 displacements per atom, dpa) at elevated temperatures (>300 C). Here, high efficiency multi-dimensional scanning transmission electron microscopy (STEM) acquisition with the aid of a three-dimensional (3D) reconstruction and modeling technique is used to probe the microstructural features that contribute to the exceptional swelling resistance of HT-9. In particular, the synergies between ' and fine-scale and moderate-scale cavity formation is investigated.

  18. Simulation of the neutron flux in the irradiation facility at RA-3 reactor

    Energy Technology Data Exchange (ETDEWEB)

    Bortolussi, S., E-mail: silva.bortolussi@pv.infn.it [Department of Nuclear and Theoretical Physics, University of Pavia, via Bassi 6 27100, Pavia (Italy)] [National Institute of Nuclear Physics (INFN), Section of Pavia, via Bassi 6 27100, Pavia (Italy); Pinto, J.M. [Department of Research and Production Reactors, Comision Nacional de Energia Atomica (CNEA), Av. del Libertador 8250 (1429), Buenos Aires (Argentina); Thorp, S.I. [Department of Instrumentations and Control, Comision Nacional de Energia Atomica (CNEA), Presbitero Luis Gonzalez y Aragon 15 (B1802AYA), Buenos Aires (Argentina); Farias, R.O. [CONICET, Avda. Rivadavia 1917, (1033) C.A.B.A. Argentina (Argentina); Soto, M.S. [FCEyN, Universidad de Buenos Aires (1428), Cdad. Universitaria. C.A.B.A. Argentina (Argentina); Sztejnberg, M. [Department of Instrumentations and Control, Comision Nacional de Energia Atomica (CNEA), Presbitero Luis Gonzalez y Aragon 15 (B1802AYA), Buenos Aires (Argentina); Pozzi, E.C.C. [Department of Research and Production Reactors, Comision Nacional de Energia Atomica (CNEA), Av. del Libertador 8250 (1429), Buenos Aires (Argentina)] [Department of Radiobiology, Comision Nacional de Energia Atomica (CNEA), Av. del Libertador 8250 (1429), Buenos Aires (Argentina)

    2011-12-15

    A facility for the irradiation of a section of patients' explanted liver and lung was constructed at RA-3 reactor, Comision Nacional de Energia Atomica, Argentina. The facility, located in the thermal column, is characterized by the possibility to insert and extract samples without the need to shutdown the reactor. In order to reach the best levels of security and efficacy of the treatment, it is necessary to perform an accurate dosimetry. The possibility to simulate neutron flux and absorbed dose in the explanted organs, together with the experimental dosimetry, allows setting more precise and effective treatment plans. To this end, a computational model of the entire reactor was set-up, and the simulations were validated with the experimental measurements performed in the facility.

  19. Pixel pitch and particle energy influence on the dark current distribution of neutron irradiated CMOS image sensors.

    Science.gov (United States)

    Belloir, Jean-Marc; Goiffon, Vincent; Virmontois, Cédric; Raine, Mélanie; Paillet, Philippe; Duhamel, Olivier; Gaillardin, Marc; Molina, Romain; Magnan, Pierre; Gilard, Olivier

    2016-02-22

    The dark current produced by neutron irradiation in CMOS Image Sensors (CIS) is investigated. Several CIS with different photodiode types and pixel pitches are irradiated with various neutron energies and fluences to study the influence of each of these optical detector and irradiation parameters on the dark current distribution. An empirical model is tested on the experimental data and validated on all the irradiated optical imagers. This model is able to describe all the presented dark current distributions with no parameter variation for neutron energies of 14 MeV or higher, regardless of the optical detector and irradiation characteristics. For energies below 1 MeV, it is shown that a single parameter has to be adjusted because of the lower mean damage energy per nuclear interaction. This model and these conclusions can be transposed to any silicon based solid-state optical imagers such as CIS or Charged Coupled Devices (CCD). This work can also be used when designing an optical imager instrument, to anticipate the dark current increase or to choose a mitigation technique.

  20. Radiation induced changes in electrical conductivity of chemical vapor deposited silicon carbides under fast neutron and gamma-ray irradiations

    Energy Technology Data Exchange (ETDEWEB)

    Tsuchiya, Bun, E-mail: btsuchiya@meijo-u.ac.jp [Department of General Education, Faculty of Science and Technology, Meijo University, 1-501, Shiogamaguchi, Tempaku-ku, Nagoya 468-8502 (Japan); Shikama, Tatsuo; Nagata, Shinji; Saito, Kesami [Institute for Materials Research, Tohoku University, 2-1-1, Katahira, Aoba-ku, Sendai 980-8577 (Japan); Yamamoto, Syunya [Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, 1233, Watanuki-machi, Takasaki, Gunma 370-1292 (Japan); Ohnishi, Seiki [Tokai Research and Development Center, Japan Atomic Energy Agency, Tokai-mura, Naka-gun, Ibaraki 319-1195 (Japan); Nozawa, Takashi [Aomori Research and Development Center, Japan Atomic Energy Agency, 2-166, Omotedate, Obuchi, Rokkasho, Aomori 039-3212 (Japan)

    2011-10-15

    The radiation-induced changes in the volume electrical conductivities of chemical vapor deposited silicon carbides (CVD-SiCs) were in-site investigated by performing irradiation using 1.17 and 1.33-MeV gamma-ray and 14-MeV fast neutron beams in air and vacuum. Under gamma-ray irradiation at ionization dose rates of 3.6 and 5.9 Gy/s and irradiation temperature of approximately 300 K, the initial rapid increase in electrical conductivity; this is indicative of radiation-induced conductivity (RIC), occurred due to electronic excitation, and a more gradual increase followed up to a dose of approximately 10-50 kGy corresponding to the results in base conductivity without radiation; this is indicative of radiation-induced electrical degradation (RIED). However, the radiation-induced phenomena were not observed at irradiation temperatures above 373 K. Under neutron irradiation at a further low dose rate below approximately 2.1 Gy/s, a fast neutron flux of 9.2 x 10{sup 14} n/m{sup 2} s, and 300 K, the RIED-like behavior according to radiation-induced modification of the electrical property occurred with essentially no displacement damage, but ionizing effects (radiolysis).

  1. Total Dose Effects on Bipolar Integrated Circuits at Low Temperature

    Science.gov (United States)

    Johnston, A. H.; Swimm, R. T.; Thorbourn, D. O.

    2012-01-01

    Total dose damage in bipolar integrated circuits is investigated at low temperature, along with the temperature dependence of the electrical parameters of internal transistors. Bandgap narrowing causes the gain of npn transistors to decrease far more at low temperature compared to pnp transistors, due to the large difference in emitter doping concentration. When irradiations are done at temperatures of -140 deg C, no damage occurs until devices are warmed to temperatures above -50 deg C. After warm-up, subsequent cooling shows that damage is then present at low temperature. This can be explained by the very strong temperature dependence of dispersive transport in the continuous-time-random-walk model for hole transport. For linear integrated circuits, low temperature operation is affected by the strong temperature dependence of npn transistors along with the higher sensitivity of lateral and substrate pnp transistors to radiation damage.

  2. Organ and Effective Dose Coefficients for Cranial and Caudal Irradiation Geometries: Neutrons

    Science.gov (United States)

    Veinot, K. G.; Eckerman, K. F.; Hertel, N. E.; Hiller, M. M.

    2017-09-01

    With the introduction of new recommendations by ICRP Publication 103, the methodology for determining the protection quantity, effective dose, has been modified. The modifications include changes to the defined organs and tissues, the associated tissue weighting factors, radiation weighting factors, and the introduction of reference sex-specific computational phantoms (ICRP Publication 110). Computations of equivalent doses in organs and tissues are now performed in both the male and female phantoms and the sex-averaged values used to determine the effective dose. Dose coefficients based on the ICRP 103 recommendations were reported in ICRP Publication 116, the revision of ICRP Publication 74 and ICRU Publication 57. The coefficients were determined for the following irradiation geometries: anterior-posterior (AP), posterior-anterior (PA), right and left lateral (RLAT and LLAT), rotational (ROT), and isotropic (ISO). In this work, the methodology of ICRP Publication 116 was used to compute dose coefficients for neutron irradiation of the body with parallel beams directed upward from below the feet (caudal) and directed downward from above the head (cranial). These geometries may be encountered in the workplace from personnel standing on contaminated surfaces or volumes and from overhead sources. Calculations of organ and tissue absorbed doses for caudal and cranial exposures to neutrons ranging in energy from 10-9 MeV to 10 GeV have been performed using the MCNP6 radiation transport code and the adult reference voxel phantoms of ICRP Publication 110. At lower energies the effective dose per particle fluence for cranial and caudal exposures is less than AP orientations while above about 30 MeV the cranial and caudal values are greater.

  3. Neutron-gamma irradiation and protein thiols: development of a protein thiol evaluation micro-method and application to irradiated baboons; Irradiation neutron-gamma et groupements thiols proteiques: developpement d`une micromethode d`evaluation des thiols proteiques et application au babouin irradie

    Energy Technology Data Exchange (ETDEWEB)

    Chancerelle, Y.; Lafond, J.L.; Della-Maura, L.; Faure, P.; Mathieu, J.; Costa, P.; Mestries, J.C.; Kergonou, J.F.

    1994-12-31

    The essential non-protein sulfhydryl compound implicated in cellular radioprotection is glutathione. Protein thiols seem to be also involved in this protection and might be scavengers for free radical injury. We developed an analytical procedure for protein thiols measurement and we applied this method in neutron-gamma irradiated baboons. Our results demonstrated the reliability and sensitivity of the procedure. They also a drastic decrease of in vivo protein thiols after irradiation. (author). 5 refs.

  4. Simultaneous impact of neutron irradiation and sputtering on the surface structure of self–damaged ITER–grade tungsten

    Directory of Open Access Journals (Sweden)

    A. I. Belyaeva

    2014-07-01

    Full Text Available Simultaneous effects of neutron irradiation and long–term sputtering on the surface relief of ITER–grade tungsten were studied. The effects of neutron–induced displacement damage have been simulated by irradiation of tungsten target with W6 + ions of 20 MeV energy. Ar+ ions with energy 600 eV were used as imitation of charge exchange atoms in ITER. The surface relief was studied after each sputtering act. The singularity in the WJ–IG surface relief was ascertained experimentally at the first time, which determines the law of roughness extension under sputtering. As follows from the experimental data, the neutron irradiation has not to make a decisive additional contribution in the processes developing under impact of charge exchange atoms only.

  5. Magnetization studies of YBa/sub 2/Cu/sub 3/Osub(7-x) irradiated by fast neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Wisniewski, A.; Baran, M.; Przyslupski, P.; Szymczak, H.; Pajaczkowska, A.; Pytel, B.; Pytel, K.

    1988-02-01

    Studies of the effect of fast neutron damage on the magnetic hysteresis of YBa/sub 2/Cu/sub 3/Osub(7-x) ceramic samples subjected to fluence of neutrons of 2x10/sup 16/ n/cm/sup 2/ up to 6x10/sup 17/ n/cm/sup 2/ have been performed. Irradiation up to dose of 1x10/sup 17/ did not cause any change in the critical temperature. However it causes a strong increase of the magnetic hysteresis which is presumably connected with the creation of defects. The critical current density at 77 K in H = 10 KOe for the sample irradiated with the dose 1x10/sup 17/ n/cm/sup 2/ was estimated to be 520 A/cm/sup 2/ as compared to 29 A/cm/sup 2/ for the reference non-irradiated sample.

  6. EPR study of gamma and neutron irradiation effects on KU1, KS-4V and Infrasil 301 silica glasses

    Energy Technology Data Exchange (ETDEWEB)

    Lagomacini, Juan C., E-mail: jc.lagomacini@uam.es [Dept. Fisica de Materiales, Universidad Autonoma de Madrid, E-28049 Madrid (Spain); Bravo, David [Dept. Fisica de Materiales, Universidad Autonoma de Madrid, E-28049 Madrid (Spain); Leon, Monica; Martin, Piedad; Ibarra, Angel [Materiales para Fusion, CIEMAT, Avda. Complutense 22, E-28040 Madrid (Spain); Martin, Agustin [Dept. Fisica e Instalaciones, ETS Arquitectura UPM, E-28040 Madrid (Spain); Lopez, Fernando J. [Dept. Fisica de Materiales, Universidad Autonoma de Madrid, E-28049 Madrid (Spain)

    2011-10-01

    Electron paramagnetic resonance (EPR) studies have been carried out on KU1 and KS-4V high purity quartz glasses and commercial silica Infrasil 301, irradiated with gamma rays up to a dose of 11.6 MGy and neutron fluences of 10{sup 21} and 10{sup 22} n/m{sup 2}. Gamma irradiations produce a much higher concentration of defect centres (mainly E', POR and NBOHC) for KU1 and I301 than for KS-4V silica. In contrast, neutron irradiation at the highest fluence produces similar concentrations in all silica types. These results agree to a good extent with those obtained in previous optical absorption measurements. Moreover, oxygen-related centres (POR and NBOHC) have been well characterized by means of electron paramagnetic resonance.

  7. Electrical Properties of MWCNT/HDPE Composite-Based MSM Structure Under Neutron Irradiation

    Science.gov (United States)

    Kasani, H.; Khodabakhsh, R.; Taghi Ahmadi, M.; Rezaei Ochbelagh, D.; Ismail, Razali

    2017-04-01

    Because of their low cost, low energy consumption, high performance, and exceptional electrical properties, nanocomposites containing carbon nanotubes are suitable for use in many applications such as sensing systems. In this research work, a metal-semiconductor-metal (MSM) structure based on a multiwall carbon nanotube/high-density polyethylene (MWCNT/HDPE) nanocomposite is introduced as a neutron sensor. Scanning electron microscopy, Fourier-transform infrared, and infrared spectroscopy techniques were used to characterize the morphology and structure of the fabricated device. Current-voltage ( I- V) characteristic modeling showed that the device can be assumed to be a reversed-biased Schottky diode, if the voltage is high enough. To estimate the depletion layer length of the Schottky contact, impedance spectroscopy was employed. Therefore, the real and imaginary parts of the impedance of the MSM system were used to obtain electrical parameters such as the carrier mobility and dielectric constant. Experimental observations of the MSM structure under irradiation from an americium-beryllium (Am-Be) neutron source showed that the current level in the device decreased significantly. Subsequently, current pulses appeared in situ I- V and current-time ( I- t) curve measurements when increasing voltage was applied to the MSM system. The experimentally determined depletion region length as well as the space-charge-limited current mechanism for carrier transport were compared with the range for protons calculated using Monte Carlo n-particle extended (MCNPX) code, yielding the maximum energy of recoiled protons detectable by the device.

  8. Low Temperature Waste Immobilization Testing Vol. I

    Energy Technology Data Exchange (ETDEWEB)

    Russell, Renee L.; Schweiger, Michael J.; Westsik, Joseph H.; Hrma, Pavel R.; Smith, D. E.; Gallegos, Autumn B.; Telander, Monty R.; Pitman, Stan G.

    2006-09-14

    The Pacific Northwest National Laboratory (PNNL) is evaluating low-temperature technologies to immobilize mixed radioactive and hazardous waste. Three waste forms—alkali-aluminosilicate hydroceramic cement, “Ceramicrete” phosphate-bonded ceramic, and “DuraLith” alkali-aluminosilicate geopolymer—were selected through a competitive solicitation for fabrication and characterization of waste-form properties. The three contractors prepared their respective waste forms using simulants of a Hanford secondary waste and Idaho sodium bearing waste provided by PNNL and characterized their waste forms with respect to the Toxicity Characteristic Leaching Procedure (TCLP) and compressive strength. The contractors sent specimens to PNNL, and PNNL then conducted durability (American National Standards Institute/American Nuclear Society [ANSI/ANS] 16.1 Leachability Index [LI] and modified Product Consistency Test [PCT]) and compressive strength testing (both irradiated and as-received samples). This report presents the results of these characterization tests.

  9. New polymer electrolytes for low temperature fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Sundholm, F.; Elomaa, M.; Ennari, J.; Hietala, S.; Paronen, M. [Univ. of Helsinki (Finland). Lab. of Polymer Chemistry

    1998-12-31

    Proton conducting polymer membranes for demanding applications, such as low temperature fuel cells, have been synthesised and characterised. Pre-irradiation methods are used to introduce sulfonic acid groups, directly or using polystyrene grafting, in stable, preformed polymer films. The membranes produced in this work show promise for the development of cost-effective, highly conducting membranes. (orig.)

  10. Ultra-low temperature MAS-DNP

    Science.gov (United States)

    Lee, Daniel; Bouleau, Eric; Saint-Bonnet, Pierre; Hediger, Sabine; De Paëpe, Gaël

    2016-03-01

    Since the infancy of NMR spectroscopy, sensitivity and resolution have been the limiting factors of the technique. Regular essential developments on this front have led to the widely applicable, versatile, and powerful spectroscopy that we know today. However, the Holy Grail of ultimate sensitivity and resolution is not yet reached, and technical improvements are still ongoing. Hence, high-field dynamic nuclear polarization (DNP) making use of high-frequency, high-power microwave irradiation of electron spins has become very promising in combination with magic angle sample spinning (MAS) solid-state NMR experiments. This is because it leads to a transfer of the much larger polarization of these electron spins under suitable irradiation to surrounding nuclei, greatly increasing NMR sensitivity. Currently, this boom in MAS-DNP is mainly performed at minimum sample temperatures of about 100 K, using cold nitrogen gas to pneumatically spin and cool the sample. This Perspective deals with the desire to improve further the sensitivity and resolution by providing "ultra"-low temperatures for MAS-DNP, using cryogenic helium gas. Different designs on how this technological challenge has been overcome are described. It is shown that stable and fast spinning can be attained for sample temperatures down to 30 K using a large cryostat developed in our laboratory. Using this cryostat to cool a closed-loop of helium gas brings the additional advantage of sample spinning frequencies that can greatly surpass those achievable with nitrogen gas, due to the differing fluidic properties of these two gases. It is shown that using ultra-low temperatures for MAS-DNP results in substantial experimental sensitivity enhancements and according time-savings. Access to this temperature range is demonstrated to be both viable and highly pertinent.

  11. Characterization of neutron flux spectra in the irradiation sites of a 37 GBq 241Am-Be isotopic source

    Science.gov (United States)

    Yücel, Haluk; Budak, Mustafa Guray; Karadag, Mustafa; Yüksel, Alptuğ Özer

    2014-11-01

    For the applicability of instrumental neutron activation analysis (NAA) technique, an irradiation unit with a 37 GBq 241Am-Be neutron source was installed at Institute of Nuclear Sciences of Ankara University. Design and configuration properties of the irradiation unit are described. It has two different sample irradiation positions, one is called site #1 having a pneumatic sample transfer system and the other is site #2 having a location for manual use. In order to characterize neutron flux spectra in the irradiation sites, the measurement results were obtained for thermal (Фth) and epithermal neutron fluxes (Фepi), thermal to epithermal flux ratio (f) and epithermal spectrum shaping factors (α) by employing cadmium ratios of gold (Au) and molybdenum (Mo) monitors. The activities produced in these foils were measured by using a p-type, 44.8% relative efficiency HPGe well detector. For the measured γ-rays, self-absorption and true coincidence summing effects were taken into account. Additionally, thermal neutron self-shielding and resonance neutron self-shielding effects were taken into account in the measured results. For characterization of site #1, the required parameters were found to be Фth = (2.11 ± 0.05) × 103 n cm-2 s-1, Фepi = (3.32 ± 0.17) × 101 n cm-2 s-1, f = 63.6 ± 1.5, α = 0.045 ± 0.009, respectively. Similarly, those parameters were measured in site #2 as Фth = (1.49 ± 0.04) × 103 n cm-2 s-1, Фepi = (2.93 ± 0.15) × 101 n cm-2 s-1, f = 50.9 ± 1.3 and α = 0.038 ± 0.008. The results for f-values indicate that good thermalization of fast neutrons on the order of 98% was achieved in both sample irradiation sites. This is because an optimum combination of water and paraffin moderator is used in the present configuration. In addition, the shielding requirements are met by using natural boron oxide powder (5.5 cm) and boron loaded paraffin layers against neutrons, and a 15 cm thick lead bricks against gamma-rays from source and its

  12. Effect of Neutron Irradiation on Properties of Pb(Mg(1/3)Nb(2/3))O3-PbTiO3.

    Science.gov (United States)

    Kim, Yong-Il; Choi, Namkyoung; Kim, Geunwoo; Lee, Yun-Hee; Baek, Kwang-Sae; Kim, Ki-Bok

    2015-11-01

    The effect of neutron irradiation on the electrical and piezoelectric properties of a PMN-PT [(Pb(Mg(1/3)Nb(2/3))O3-PbTiO3)] single crystal such as permittivity, electrical impedance and piezoelectric constant d33 has been investigated at 1 kHz. The changes of d33 and permittivity depending on the dose of neutron irradiation for all samples of PMN-PT single crystal were found. In all samples, the permittivity, and piezoelectric constant d33 decreased with the increase of irradiation dose. Changes of XRD patterns depending on the dose of neutron irradiation for all samples were found. From the results of XRDs for analyzing the formation of the PMN-PT single crystals in single phase, the neutron irradiation will affect the crystallinity of PMN-PT single crystals.

  13. Microdosimetric measurements in the thermal neutron irradiation facility of LENA reactor.

    Science.gov (United States)

    Colautti, P; Moro, D; Chiriotti, S; Conte, V; Evangelista, L; Altieri, S; Bortolussi, S; Protti, N; Postuma, I

    2014-06-01

    A twin TEPC with electric-field guard tubes has been constructed to be used to characterize the BNCT field of the irradiation facility of LENA reactor. One of the two mini TEPC was doped with 50ppm of (10)B in order to simulate the BNC events occurring in BNCT. By properly processing the two microdosimetric spectra, the gamma, neutron and BNC spectral components can be derived with good precision (~6%). However, direct measurements of (10)B in some doped plastic samples, which were used for constructing the cathode walls, point out the scarce accuracy of the nominal (10)B concentration value. The influence of the Boral(®) door, which closes the irradiation channel, has been measured. The gamma dose increases significantly (+51%) when the Boral(®) door is closed. The crypt-cell-regeneration weighting function has been used to measure the quality, namely the RBEµ value, of the radiation field in different conditions. The measured RBEµ values are only partially consistent with the RBE values of other BNCT facilities.

  14. Localised vibrational mode spectroscopy studies of self-interstitial clusters in neutron irradiated silicon

    Energy Technology Data Exchange (ETDEWEB)

    Londos, C. A.; Antonaras, G. [University of Athens, Solid State Physics Section, Panepistimiopolis Zografos, Athens 157 84 (Greece); Chroneos, A. [Materials Engineering, The Open University, Milton Keynes MK7 6AA (United Kingdom); Department of Materials, Imperial College, London SW7 2AZ (United Kingdom)

    2013-07-28

    The evolution of self-interstitial clusters in silicon (Si), produced by fast neutron irradiation of silicon crystals followed by anneals up to 750 °C, is investigated using localised vibrational mode spectroscopy. A band at 582 cm{sup −1} appears after irradiation and is stable up to 550 °C was attributed to small self-interstitial clusters (I{sub n}, n ≤ 4), with the most probable candidate the I{sub 4} structure. Two bands at 713 and 758 cm{sup −1} arising in the spectra upon annealing of the 582 cm{sup −1} band and surviving up to ∼750 °C were correlated with larger interstitial clusters (I{sub n}, 5 ≤ n ≤ 8), with the most probable candidate the I{sub 8} structure or/and with chainlike defects which are precursors of the (311) extended defects. The results illustrate the presence of different interstitial clusters I{sub n}, at the various temperature intervals of the material, in the course of an isochronal anneal sequence. As the annealing temperature increases, they evolve from first-order structures with a small number of self-interstitials (I{sub n}, n ≤ 4) for the temperatures 50 < T < 550 °C, to second order structures (I{sub n}, 5 ≤ n ≤ 8) with a larger number of interstitials, for the temperatures 550 < T < 750 °C.

  15. Fracture behaviors of neutron-irradiated ferritic steels studied by the instrumented charpy impact test

    Science.gov (United States)

    Yoshida, H.; Miyata, K.; Narui, M.; Kayano, H.

    1989-12-01

    The instrumented Charpy impact test for quarter-size specimens was developed and applied to study fracture behavior of ferritic steels and a ferritic-martensitic steel (JFMS) before and after neutron irradiation. The load-deflection curves obtained for U- and V-notched specimens showed typical characteristics of fracture properties of these steels. The temperature dependence of the fracture energy ( Ef) and the failure deflection ( Df) clearly indicates ductile-brittle transition and the DBTT can be determined from the Ef and Df versus temperature curves. The V-notched specimens showed sharper transition at higher temperatures for the JFMS than the U-notched ones, where the former were sensitive to brittle fracture and the latter well demonstrated the behavior of crack propagation. For the ferritic steels the DBTTs showed low values at compositions containing approximate 8-10% Cr and the increase of the DBTT (Δ DBTT) due to irradiation also showed a similar tendency. The Δ DBTT appeared to be relatively larger for the JFMS than the ferritic steels.

  16. Microstructural changes of Y-doped V-4Cr-4Ti alloys after ion and neutron irradiation

    Directory of Open Access Journals (Sweden)

    H. Watanabe

    2016-12-01

    Full Text Available High-purity Y-doped V-4Cr-4Ti alloys (0.1–0.2wt. % Y, manufactured by the National Institute for Fusion Science (NIFS, were used for this study. Heavy-ion and fission-neutron irradiation was carried out at temperatures 673–873K. During the ion irradiation at 873K, the microstructure was controlled by the formation of Ti(C,O,N precipitates lying on the (100 plane. Y addition effectively suppressed the growth of Ti(C,O,N precipitates, especially at lower dose irradiation to up to 4 dpa. However, at higher dose levels (12.0 dpa, the number density was almost at the same levels irrespective of the presence of Y. After neutron irradiation at 873K, fine titanium oxides were also observed in all V alloys. However, smaller oxide sizes were observed in the Y-doped samples under the same irradiation conditions. The detailed analysis of EDS showed that the center of the Ti(C,O,N precipitates was mainly enriched by nitrogen. The results showed that the contribution of not only oxygen atoms picked up from the irradiation environment but also nitrogen atoms is essential to understand the microstructural evolution of V-4Cr-4Ti-Y alloys.

  17. Decommissioning of an Irradiator MPX-{gamma} - 25M and a neutron Irradiator; Desmantelamiento de un irradiador tipo MPX-{gamma}-25M y de un irradiador de neutrones

    Energy Technology Data Exchange (ETDEWEB)

    Soguero, Dania; Guerra, Mercedes; Prieto, Enrique; Desdin, Luis, E-mail: sdania@ceaden.edu.cu [Centro de Aplicaciones Tecnologica y Desarrollo Nuclear (CEADEN), La Habana (Cuba)

    2013-07-01

    In this paper a technology is developed with its procedures in radiation protection to ensure the safety of the process of decommissioning of two irradiators. Both processes are described, the process of decommissioning of a neutron Irradiator 4. 44{center_dot}10{sup 11}Bq, employed in the vegetal radio mutagenesis, and disassembling of an installation of gamma irradiation of 3.33 * 10{sup 12} Bq, self-shielded of category I, model MPX - {gamma} - 25 M. The specific objectives are: a) identify aspects of the contractual assurance, of human and technical resources, b) to evaluate the radiological situation of the process and c) analyze the potential radiological extraordinary events in each of the steps of the process, ensuring the right answers. Evaluation of radiological successful events described can be considered as reference to address the process of disassembling of other similar irradiators.

  18. Subtask 12F4: Effects of neutron irradiation on the impact properties and fracture behavior of vanadium-base alloys

    Energy Technology Data Exchange (ETDEWEB)

    Chung, H.M.; Loomis, B.A.; Smith, D.L. [Argonne National Lab., IL (United States)

    1995-03-01

    Up-to-date results on the effects of neutron irradiation on the impact properties and fracture behavior of V, V-Ti, V-Cr-Ti and V-Ti-Si alloys are presented in this paper, with an emphasis on the behavior of the U.S. reference alloys V-4Cr-4Ti containing 500-1000 wppm Si. Database on impact energy and cluctile-brittle transition temperature (DBTT) has been established from Charpy impact tests of one-third-size specimens irradiated at 420{degrees}C-600{degrees}C up to {approx}50 dpa in lithium environment in fast fission reactors. To supplement the Charpy impact tests fracture behavior was also characterized by quantitative SEM fractography on miniature tensile and disk specimens that were irradiated to similar conditions and fractured at -196{degrees}C to 200{degrees}C by multiple bending. For similar irradiation conditions irradiation-induced increase in DBTT was influenced most significantly by Cr content, indicating that irradiation-induced clustering of Cr atoms takes place in high-Cr (Cr {ge} 7 wt.%) alloys. When combined contents of Cr and Ti were {le}10 wt.%, effects of neutron irradiation on impact properties and fracture behavior were negligible. For example, from the Charpy-impact and multiple-bend tests there was no indication of irradiation-induced embrittlement for V-5Ti, V-3Ti-1Si and the U.S. reference alloy V-4Cr-4Ti after irradiation to {approx}34 dpa at 420{degrees}C to 600{degrees}C, and only ductile fracture was observed for temperatures as low as -196{degrees}C. 14 refs., 8 figs., 1 tab.

  19. Irradiation effects in 6H-SiC induced by neutron and heavy ions: Raman spectroscopy and high-resolution XRD analysis

    Science.gov (United States)

    Chen, Xiaofei; Zhou, Wei; Feng, Qijie; Zheng, Jian; Liu, Xiankun; Tang, Bin; Li, Jiangbo; Xue, Jianming; Peng, Shuming

    2016-09-01

    Irradiation effects of neutron and 3 MeV C+, Si+ in 6H-SiC were investigated by Raman spectroscopy and high-resolution XRD. The total disorder values of neutron irradiated SiC agree well with that of samples irradiated by ions at the same doses respectively. On the other hand, high-resolution XRD results shows that the lattice strain rate caused by neutron irradiation is 6.8%/dpa, while it is only 2.6%/dpa and 4.2%/dpa for Si+ and C+ irradiations respectively. Our results illustrate that the total disorder in neutron irradiated SiC can be accurately simulated by MeV Si+ or C+ irradiations at the same dose, but for the lattice strain and strain-related properties like surface hardness, the depth profile of irradiation damages induced by energetic ions must be considered. This research will contribute to a better understanding of the difference in irradiation effects between neutron and heavy ions.

  20. Effects of neutron irradiation on microstructure and mechanical properties of pure iron

    DEFF Research Database (Denmark)

    Singh, B.N.; Horsewell, Andy; Toft, P.

    1999-01-01

    tensile tested at the irradiation temperatures. Microstructures of the as-irradiated and irradiated and tensile tested specimens were investigated by transmission electron microscopy. Fracture surfaces of tensile tested specimens in unirradiated and irradiated conditions were examined in a scanning...

  1. Tooth enamel EPR dosimetry of neutrons: Enhancement of the apparent sensitivity at irradiation in the human head phantom

    Energy Technology Data Exchange (ETDEWEB)

    Khailov, A.M. [Medical Radiological Research Center, Korolyov str., 4, Obninsk 249032 (Russian Federation); Ivannikov, A.I. [Medical Radiological Research Center, Korolyov str., 4, Obninsk 249032 (Russian Federation)], E-mail: ivannikov@mrrc.obninsk.ru; Tikunov, D.D.; Skvortsov, V.G.; Stepanenko, V.F. [Medical Radiological Research Center, Korolyov str., 4, Obninsk 249032 (Russian Federation); Zhumadilov, K.; Tanaka, K.; Endo, S.; Hoshi, M. [Research Institute for Radiation Biology and Medicine, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima 734-8553 (Japan)

    2007-07-15

    Induction of the EPR signal in tooth enamel at irradiation by the neutrons produced by a generator with maximal energy of 0.8 MeV in the air and in the human head phantom was investigated. Neutron and photon tissue absorbed doses in the mixed radiation field were determined experimentally and calculated using the Monte-Carlo method. It is shown that the EPR signal response of enamel to neutrons relative to the tissue dose is (2{+-}2)% of the appropriate value for {sup 60}Co gamma radiation. At irradiation in the human head phantom, the EPR signal response relatively to the input neutron tissue dose near the surface of the phantom (apparent EPR sensitivity to neutrons) increases to (14{+-}1)%. The observed EPR signal enhancement is caused by absorption in enamel of the secondary photons produced at H(n,{gamma})H{sup 2}, E{sub {gamma}}=2.23MeV reaction in the material of the phantom.

  2. RBE values for colo-rectal injury after caesium 137 gamma-ray and neutron irradiation. 1. Single doses

    Energy Technology Data Exchange (ETDEWEB)

    Terry, N.H.A.; Denekamp, J.; Maughan, R.L. (Mount Vernon Hospital, Northwood (UK). Gray Lab.)

    1983-04-01

    Colo-rectal damage in mice has been assessed after caesium ..gamma.. irradiation and 3 MeV neutrons given as single doses. Several assays were used, including body weight changes, faecal deformity and lethality. Dose response curves were constructed for each assay at times ranging from 10 days to 16 months after irradiation. An initial loss of weight at 10-20 days was presumably related to epithelial denudation, but a dose-dependent weight reduction (compared with controls) persisted over the animals' life span. Mice died progressively after localised pelvic ..gamma.. irradiation; there was no sharp demarcation between an early and late phase of lethal injury. Death resulted from intestinal stricture or stenosis. The time course for lethality was qualitatively different after neutron irradiation, with little progression of damage between 5 and 11 months. Faecal deformity was detectable as a higher proportion of small pellets when the rectum became constricted by fibrosis. No significant faecal deformity was observed before 6 months after which time dose response curves could be obtained. The RBE for early damage (assessed at 1-3 months) was 2.2-2.7, falling to 1.7-1.9 for late damage (determined at 10-15 months) over the range of neutron doses of 7.5-12 Gy.

  3. Neutron irradiation and frequency effects on the electrical conductivity of nanocrystalline silicon carbide (3C-SiC)

    Science.gov (United States)

    Huseynov, Elchin

    2016-09-01

    In this present work nanocrystalline silicon carbide (3C-SiC) has been irradiated with neutron flux (∼ 2 ×1013 ncm-2s-1) up to 20 hours at different periods. Electrical conductivity of nanocrystalline 3C-SiC particles (∼18 nm) is comparatively analyzed before and after neutron irradiation. The frequency dependencies of electrical conductivity of 3C-SiC nanoparticles is reviewed at 100 K-400 K temperature range before and after irradiation. The measurements were carried out at 0.1 Hz-2.5 MHz frequency ranges and at different temperatures. Radiation-induced conductivity (RIC) was observed in the nanocrystalline 3C-SiC particles after neutron irradiation and this conductivity study as a function of frequency are presented. The type of conductivity has been defined based on the interdependence between real and imaginary parts of electrical conductivity function. Based on the obtained results the mechanism behind the electrical conductivity of nanocrystalline 3C-SiC particles is explained in detail.

  4. Characterization of Neutron and Gamma Dose in the Irradiation Cell of Texas A and M University Research Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Vasudevan, Latha; Reece, Warren D. [Nuclear Science Center, Texas A and M University, College Station, Texas (United States); Chirayath, Sunil S. [Nuclear Security Science and Policy Institute, Texas A and M University, College Station, Texas (United States); Aghara, Sukesh [Prairie View A and M University, Prairie View, Texas (United States)

    2011-07-01

    The Monte Carlo N-Particle (MCNP) code was used to develop a three dimensional computational model of the Texas A and M University Nuclear Science Center Reactor (NSCR) operating against the irradiation (dry cell) at steady state thermal power of 1 MW. The geometry of the NSCR core and the dry cell were modeled in detail. NSCR is used for a wide variety of experiments that utilizes the dry cell for neutron as well as gamma irradiation of samples. Information on the neutron and gamma radiation environment inside the dry cell is required to facilitate irradiation of samples. This paper presents the computed neutron flux, neutron and gamma dose rate, and foil reaction rates in the dry cell, obtained through MCNP5 simulations of the NSCR core. The neutron flux was measured using foil activation method and the reaction rates obtained from {sup 197}Au(n,{gamma}){sup 198}Au and {sup 54}Fe(n,p){sup 54}Mn were compared with the model and they showed agreement within {approx} 20%. The gamma dose rate at selected locations inside the dry cell was measured using radiochromic films and the results indicate slightly higher dose rates than predicted from the model. This is because the model calculated only prompt gamma dose rates during reactor operation while the radiochromic films measured gammas from activation products and fission product decayed gammas. The model was also used to calculate the neutron energy spectra for the energy range from 0.001 eV- 20 MeV. (authors)

  5. DLTS and capacitance transients study of defects induced by neutron irradiation in MOS structures CCD process; Etude des defauts induits par irradiation neutron dans des structures MOS par spectroscopie DLTS et reponses transitoires de capacite en fonction du temps

    Energy Technology Data Exchange (ETDEWEB)

    Ahaitouf, A.; Losson, E.; Charles, J.P. [Metz Univ., Lab. Interfaces Composants et Microelectronique, LICM/CLOES/ Supelec, 57 (France)

    1999-07-01

    The aim of this paper is to study neutron irradiation effects on PMOS capacitors and NMOSFETs transistors. The characterization of induced defects was made by capacitance transients C(t) measurements, DLTS spectroscopy, and optical DLTS (ODLTS). DLTS spectra present three peaks due to deep levels created in the semiconductor and two peaks due to minority carrier generation. Two levels are reported in the literature. Two other minority carrier traps have been observed on ODLTS spectra after irradiation. This can explain the decrease of the minority carrier generation lifetime observed by capacitance transients measurements. (authors)

  6. Overview of the US-Japan collaborative investigation on hydrogen isotope retention in neutron-irradiated and ion-damaged tungsten

    Energy Technology Data Exchange (ETDEWEB)

    Masashi Shimada; Y. Hatano; Y. Oya; T. Oda; M. Hara; G. Cao; M. Kobayashi; M. Sokolov; H. Watanabe; B. Tyburska; Y. Ueda; P. Calderoni

    2011-09-01

    Plasma-facing components (PFCs) will be exposed to 14 MeV neutrons from deuterium-tritium (D-T) fusion reactions, and tungsten, a candidate PFC for the divertor in ITER, is expected to receive a neutron dose of 0.7 displacement per atom (dpa) by the end of operation in ITER. The effect of neutron-irradiation damage has been mainly simulated using high-energy ion bombardment. While this prior database of results is quite valuable for understanding the behavior of hydrogen isotopes in PFCs, it does not encompass the full range of effects that must be considered in a practical fusion environment due to short penetration depth, damage gradient, high damage rate, and high PKA energy spectrum of the ion bombardment. In addition, neutrons change the elemental composition via transmutations, and create a high radiation environment inside PFCs, which influence the behavior of hydrogen isotope in PFCs, suggesting the utilization of fission reactors is necessary for neutron irradiation. Therefore, the effort to correlate among high-energy ions, fission neutrons, and fusion neutrons is crucial for accurately estimating tritium retention under a neutron-irradiation environment. Under the framework of the US-Japan TITAN program, tungsten samples (99.99 at. % purity from A.L.M.T. Co.) were irradiated by neutron in the High Flux Isotope Reactor (HFIR), ORNL, at 50 and 300C to 0.025, 0.3, and 1.2 dpa, and the investigation of deuterium retention in neutron-irradiation was performed in the INL Tritium Plasma Experiment (TPE), the unique high-flux linear plasma facility that can handle tritium, beryllium and activated materials. This paper reports the recent results from the comparison of ion-damaged tungsten via various ion species (2.8 MeV Fe2+, 20 MeV W2+, and 700 keV H-) with that from neutron-irradiated tungsten to identify the similarities and differences among them.

  7. Tritium and helium release from beryllium pebbles neutron-irradiated up to 230appm tritium and 3000appm helium

    Directory of Open Access Journals (Sweden)

    Vladimir Chakin

    2016-12-01

    Full Text Available Study of tritium and helium release from beryllium pebbles with diameters of 0.5 and 1mm after high-dose neutron irradiation at temperatures of 686–968K was performed. The release rate always has a single peak, and the peak temperatures at heating rates of 0.017K/s and 0.117K/s lie in the range of 1100–1350K for both tritium and helium release. The total tritium release from 1mm pebbles decreases considerably by increasing the irradiation temperature. The total tritium release from 0.5mm pebbles is less than that from 1mm pebbles and remains constant regardless of the irradiation temperature. At high irradiation temperatures, open channels are formed which contribute to the enhanced tritium release.

  8. In vivo skin leptin modulation after 14 MeV neutron irradiation: a molecular and FT-IR spectroscopic study

    Energy Technology Data Exchange (ETDEWEB)

    Cestelli Guidi, M.; Mirri, C.; Marcelli, A. [Laboratori Nazionali di Frascati - INFN, Frascati, Rome (Italy); Fratini, E.; Amendola, R. [ENEA, UT BIORAD-RAB, Rome (Italy); Licursi, V.; Negri, R. [Universita La Sapienza, Dip. Biologia e Biotecnologie ' ' Charles Darwin' ' , Rome (Italy)

    2012-09-15

    This paper discusses gene expression changes in the skin of mice treated by monoenergetic 14 MeV neutron irradiation and the possibility of monitoring the resultant lipid depletion (cross-validated by functional genomic analysis) as a marker of radiation exposure by high-resolution FT-IR (Fourier transform infrared) imaging spectroscopy. The irradiation was performed at the ENEA Frascati Neutron Generator (FNG), which is specifically dedicated to biological samples. FNG is a linear electrostatic accelerator that produces up to 1.0 x 10{sup 11} 14-MeV neutrons per second via the D-T nuclear reaction. The functional genomic approach was applied to four animals for each experimental condition (unirradiated, 0.2 Gy irradiation, or 1 Gy irradiation) 6 hours or 24 hours after exposure. Coregulation of a subclass of keratin and keratin-associated protein genes that are physically clustered in the mouse genome and functionally related to skin and hair follicle proliferation and differentiation was observed. Most of these genes are transiently upregulated at 6 h after the delivery of the lower dose delivered, and drastically downregulated at 24 h after the delivery of the dose of 1 Gy. In contrast, the gene coding for the leptin protein was consistently upregulated upon irradiation with both doses. Leptin is a key protein that regulates lipid accumulation in tissues, and its absence provokes obesity. The tissue analysis was performed by monitoring the accumulation and the distribution of skin lipids using FT-IR imaging spectroscopy. The overall picture indicates the differential modulation of key genes during epidermis homeostasis that leads to the activation of a self-renewal process at low doses of irradiation. (orig.)

  9. Heterogeneous dislocation loop formation near grain boundaries in a neutron-irradiated commercial FeCrAl alloy

    Science.gov (United States)

    Field, Kevin G.; Briggs, Samuel A.; Hu, Xunxiang; Yamamoto, Yukinori; Howard, Richard H.; Sridharan, Kumar

    2017-01-01

    FeCrAl alloys are an attractive class of materials for nuclear power applications because of their increased environmental compatibility compared with more traditional nuclear materials. Preliminary studies into the radiation tolerance of FeCrAl alloys under accelerated neutron testing between 300 and 400 °C have shown post-irradiation microstructures containing dislocation loops and a Cr-rich α‧ phase. Although these initial studies established the post-irradiation microstructures, there was little to no focus on understanding the influence of pre-irradiation microstructures on this response. In this study, a well-annealed commercial FeCrAl alloy, Alkrothal 720, was neutron irradiated to 1.8 displacements per atom (dpa) at 382 °C and then the effect of random high-angle grain boundaries on the spatial distribution and size of a dislocation loops, a/2 dislocation loops, and black dot damage was analyzed using on-zone scanning transmission electron microscopy. Results showed a clear heterogeneous dislocation loop formation with a/2 dislocation loops showing an increased number density and size, black dot damage showing a significant number density decrease, and a dislocation loops exhibiting an increased size in the vicinity of the grain boundary. These results suggest the importance of the pre-irradiation microstructure and, specifically, defect sink density spacing to the radiation tolerance of FeCrAl alloys.

  10. Low temperature diffusivity of self-interstitial defects in tungsten

    Science.gov (United States)

    Swinburne, Thomas D.; Ma, Pui-Wai; Dudarev, Sergei L.

    2017-07-01

    The low temperature diffusivity of nanoscale crystal defects, where quantum mechanical fluctuations are known to play a crucial role, are essential to interpret observations of irradiated microstructures conducted at cryogenic temperatures. Using density functional theory calculations, quantum heat bath molecular dynamics and open quantum systems theory, we evaluate the low temperature diffusivity of self-interstitial atom clusters in tungsten valid down to temperatures of 1 K. Due to an exceptionally low defect migration barrier, our results show that interstitial defects exhibit very high diffusivity of order {10}3 μ {{{m}}}2 {{{s}}}-1 over the entire range of temperatures investigated.

  11. High-dose neutron induced radiation swelling simulated by heavy ion irradiation and its microscopic study with positron annihilation technique

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    70 MeV-carbon-ion irradiation is used to simulate the radiation swelling induced by neutron irradiation of 3.2×1022 n·cm-2 in domestically-made 316 austenitic stainless steels modified by a 20%-cold-working and Ti-adding from room temperature to 802°C. The created swelling is microscopically examined by the positron annihilation lifetime technique. A radiation swelling peak is observed at 580°C and the corresponding void has an average diameter of 0.7nm which is hardly probed by macroscopic methods.

  12. Neutron irradiation of V-Cr-Ti alloys in the BOR-60 fast reactor: Description of the fusion-1 experiment

    Energy Technology Data Exchange (ETDEWEB)

    Rowcliffe, A.F. [Oak Ridge National Laboratory, TN (United States); Tsai, H.C.; Smith, D.L. [Argonne National Lab., IL (United States)] [and others

    1997-08-01

    The FUSION-1 irradiation capsule was inserted in Row 5 of the BOR-60 fast reactor in June 1995. The capsule contains a collaborative RF/U.S. experiment to investigate the irradiation performance of V-Cr-Ti alloys in the temperature range 310 to 350{degrees}C. This report describes the capsule layout, specimen fabrication history, and the detailed test matrix for the U.S. specimens. A description of the operating history and neutronics will be presented in the next semiannual report.

  13. Experimental verification of equilibrium para-hydrogen levels in hydrogen moderators irradiated by spallation neutrons at J-PARC

    Science.gov (United States)

    Teshigawara, M.; Harada, M.; Tatsumoto, H.; Aso, T.; Ohtsu, K.; Takada, H.; Futakawa, M.; Ikeda, Y.

    2016-02-01

    By sampling gaseous hydrogen from a circulating liquid hydrogen loop for Laser Raman spectroscopy, we measured the para-/ortho-hydrogen fractions in liquid hydrogen under neutron irradiation for the first time to identify whether irradiated hydrogen has an elevated ortho-hydrogen fraction. This measurement indicates that para-hydrogen equilibrium persists at 300 kW proton power in the presence of an iron(III) oxide hydroxide [Fe(OH)3] catalyst. The measurements will be repeated as the power at the Japan Proton Accelerator Research Complex (J-PARC) increases to the MW level.

  14. Comparison between different types of glass and aluminum as containers for irradiation samples by neutron activation analysis.

    Science.gov (United States)

    Sroor, A; El-Dine, N W; El-Shershaby, A; Abdel-Haleem, A S

    2000-01-01

    Three different types of glass and four different kinds of aluminum sheet have been analyzed using neutron activation analysis. The irradiation facilities of the first Egyptian research reactor (ET-RR-1) and a hyper-pure germanium (HPGe) detection system were used for the analysis. Among the 34 identified elements, the isotopes 60Co, 65Zn, 110mAg, 123mTe, 134Cs, 152Eu and 182Ta are of special significance because of their long half-lives, providing a background interference for analyzed samples. A comparison between the different types of containers was made to select the preferred one for sample irradiation.

  15. Study of neutron spectra in a water bath from a Pb target irradiated by 250 MeV protons

    Science.gov (United States)

    Li, Yan-Yan; Zhang, Xue-Ying; Ju, Yong-Qin; Ma, Fei; Zhang, Hong-Bin; Chen, Liang; Ge, Hong-Lin; Wan, Bo; Luo, Peng; Zhou, Bin; Zhang, Yan-Bin; Li, Jian-Yang; Xu, Jun-Kui; Wang, Song-Lin; Yang, Yong-Wei; Yang, Lei

    2015-04-01

    Spallation neutrons were produced by the irradiation of Pb with 250 MeV protons. The Pb target was surrounded by water which was used to slow down the emitted neutrons. The moderated neutrons in the water bath were measured by using the resonance detectors of Au, Mn and In with a cadmium (Cd) cover. According to the measured activities of the foils, the neutron flux at different resonance energies were deduced and the epithermal neutron spectra were proposed. Corresponding results calculated with the Monte Carlo code MCNPX were compared with the experimental data to check the validity of the code. The comparison showed that the simulation could give a good prediction for the neutron spectra above 50 eV, while the finite thickness of the foils greatly effected the experimental data in low energy. It was also found that the resonance detectors themselves had great impact on the simulated energy spectra. Supported by National Natural Science Foundation and Strategic Priority Research Program of the Chinese Academy of Sciences (11305229, 11105186, 91226107, 91026009, XDA03030300)

  16. Neutron irradiation tests on B4C/epoxy composite for neutron shielding application and the parameters assay

    Science.gov (United States)

    Adeli, Ruhollah; Shirmardi, Seyed Pezhman; Ahmadi, Seyed Javad

    2016-10-01

    In this investigation, epoxy resin with a low viscosity amine-based curing agent was chosen as matrix and additives were added to epoxy resin using low speed stirring with ultrasonic waves approach. The chemical stability of resin during fabrication of composites was studied with Fourier transform infrared spectroscopy (FTIR). The effect of B4C particle size (20 and 150 μm) on neutron shielding was investigated. Besides, in order to develop the high performance composites, the effect of ATH (flame retardant) and WO3 powders (for shielding from against gamma rays) on neutron shielding property is considered. The neutron experiments were based on foil activation analysis in thermal column of Tehran Research Reactor (TRR). According to experimental data, required shield thickness (B4C, 150 μm, 3 wt%) for 80% absorption of neutron fluence was calculated about 9.8 mm. Consequently, data show thermal neutron absorption is dependent also on the size of the boron compound filler and show a significant enhancement in shielding performance when using smaller particle size of B4C filler. Furthermore, data obviously show that the neutron attenuation coefficient of reinforced composites increases to 0.345 cm-1 for B4C (20 μm, 5 wt%)/ Epoxy composite shield. As clearly data indicate, adding WO3 and ATH additive had a significant influence on the thermal neutron attenuation property and hybrid shield shows an enhancement of more than 60% in shielding performance.

  17. On the onset of void swelling in pure tungsten under neutron irradiation: An object kinetic Monte Carlo approach

    Science.gov (United States)

    Castin, N.; Bakaev, A.; Bonny, G.; Sand, A. E.; Malerba, L.; Terentyev, D.

    2017-09-01

    We propose an object kinetic Monte Carlo (OKMC) model for describing the microstructural evolution in pure tungsten under neutron irradiation. We here focus on low doses (under 1 dpa), and we neglect transmutation in first approximation. The emphasis is mainly centred on an adequate description of neutron irradiation, the subsequent introduction of primary defects, and their thermal diffusion properties. Besides grain boundaries and the dislocation network, our model includes the contribution of carbon impurities, which are shown to have a strong influence on the onset of void swelling. Our parametric study analyses the quality of our model in detail, and confronts its predictions with experimental microstructural observations with satisfactory agreement. We highlight the importance for an accurate determination of the dissolved carbon content in the tungsten matrix, and we advocate for an accurate description of atomic collision cascades, in light of the sensitivity of our results with respect to correlated recombination.

  18. The Low Temperature Microgravity Physics Facility Project

    Science.gov (United States)

    Chui, T.; Holmes, W.; Lai, A.; Croonquist, A.; Eraker, J.; Abbott, R.; Mills, G.; Mohl, J.; Craig, J.; Balachandra, B.; hide

    2000-01-01

    We describe the design and development of the Low Temperature Microgravity Physics Facility, which is intended to provide a unique environment of low temperature and microgravity for the scientists to perform breakthrough investigations on board the International Space Station.

  19. The Low Temperature Microgravity Physics Facility

    Science.gov (United States)

    Pensinger, J. F.; Chui, T.; Croonquist, A.; Larson, M.; Liu, F.

    2002-01-01

    The Low Temperature Microgravity Physics Facility currently in the design phase is a multiple user and multiple flight facility intended to provide a long duration low temperature environment onboard the International Space Station.

  20. Unfolding the measured neutron spectra in the irradiation chamber of the UZrH reactor using iterative method

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In the procedure of neutron fluence measurement in the whole energy range (10-4 eV~18 MeV), in the irradiation chamber of a UZrH reactor, the neutron energy spectra are unfolded using the method of minimizing directed divergence and SAND-Ⅱ, which are used broadly at home and abroad. These methods belong to the iterative methods.In this article, the procedure of the spectra unfolding using the two methods is described in detail. The neutron spectrum distribution unfolded by the two methods agree well with each other. In the end, the major differences of the two iterative methods are compared with each other, and the main factors affecting the accuracy of the spectra unfolding with the iterative method are discussed.

  1. Neutron irradiation and high temperature effects on amorphous Fe-based nano-coatings on steel - A macroscopic assessment

    Science.gov (United States)

    Simos, N.; Zhong, Z.; Dooryhee, E.; Ghose, S.; Gill, S.; Camino, F.; Şavklıyıldız, İ.; Akdoğan, E. K.

    2017-06-01

    The study revealed that loss of ductility in an amorphous Fe-alloy coating on a steel substrate composite structure was essentially prevented from occurring, following radiation with modest neutron doses of ∼2 × 1018 n/cm2. At the higher neutron dose of ∼2 × 1019, macroscopic stress-strain analysis showed that the amorphous Fe-alloy nanostructured coating, while still amorphous, experienced radiation-induced embrittlement, no longer offering protection against ductility loss in the coating-substrate composite structure. Neutron irradiation in a corrosive environment revealed exemplary oxidation/corrosion resistance of the amorphous Fe-alloy coating, which is attributed to the formation of the Fe2B phase in the coating. To establish the impact of elevated temperatures on the amorphous-to-crystalline transition in the amorphous Fe-alloy, electron microscopy was carried out which confirmed the radiation-induced suppression of crystallization in the amorphous Fe-alloy nanostructured coating.

  2. Effects of the neutronic irradiation on the impact tests. Efectos de la irradiacion neutronica sobre los ensayos de resiliencia

    Energy Technology Data Exchange (ETDEWEB)

    Lapea, J.; Perosanz, F.J.; Hernandez, M.T.

    1993-01-01

    The changes that the Charpy curves suffer when steel is exposed to neutronic fluence are studied. Three steels with different chemical composition were chosen, two of them (JPF and JPJ) being treated at only one neutronic fluence, while the last one (JRQ) was irradiated at three fluences. In this way, it was possible to compare the effect of increasing the neutronic dose, and to study the experimental results as a function of the steel chemical composition. Two characteristic facts have been observed: the displacement of the curve at higher temperatures, and decrease of the upper shelf energy (USE). The mechanical recovery of the materials after two different thermal treatments is also described, and a comparation between the experimental results obtained and the damage prediction formulas given by different regulatory international organisms in the nuclear field is established. Author. 11 refs.

  3. Post-irradiation annealing of Ni–Mn–Si-enriched clusters in a neutron-irradiated RPV steel weld using Atom Probe Tomography

    Energy Technology Data Exchange (ETDEWEB)

    Styman, P.D., E-mail: paul.styman@materials.ox.ac.uk [National Nuclear Laboratory, 168 Harwell Business Centre, Didcot, Oxon OX11 0QT (United Kingdom); Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Hyde, J.M. [National Nuclear Laboratory, 168 Harwell Business Centre, Didcot, Oxon OX11 0QT (United Kingdom); Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); School of Materials, University of Manchester, Manchester M13 9PL (United Kingdom); Parfitt, D.; Wilford, K. [Rolls-Royce, PO BOX 2000, Raynesway, Derby DE21 7XX (United Kingdom); Burke, M.G. [School of Materials, University of Manchester, Manchester M13 9PL (United Kingdom); English, C.A. [National Nuclear Laboratory, 168 Harwell Business Centre, Didcot, Oxon OX11 0QT (United Kingdom); Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); School of Materials, University of Manchester, Manchester M13 9PL (United Kingdom); Efsing, P. [Vattenfall Ringhals AB, Väröbacka (Sweden)

    2015-04-15

    Highlights: • Characterisation of high Ni neutron irradiated RPV surveillance samples at high fluence. • Post-irradiation annealing performed to give insight into the formation mechanisms of Ni–Mn–Si precipitates. • Dissolution of Ni–Mn–Si clusters appears to be lead by the removal of Mn. - Abstract: Atom Probe Tomography has been performed on as-irradiated and post-irradiation annealed surveillance weld samples from Ringhals Unit 3. The weld contains low Cu (0.07 at.%) and high Ni (1.5 at.%). A high number density (∼4 × 10{sup 23} m{sup −3}) of Ni–Mn–Si-enriched clusters was observed in the as-irradiated material. The onset of recovery was observed during the annealing for 30 min at 450 °C. Much more significant dissolution of clusters occurred during the 10 min 500 °C anneal, resulting in a reduction in mean cluster size and a halving of their volume fraction. Detailed analyses of the changes in microstructure demonstrate that the dissolution process is driven by migration of Mn atoms from the clusters. This may indicate a strong correlation between Mn and point defects. Dissolution of the clusters is shown to correlate with recovery of mechanical properties in this material.

  4. Evaluation of the dark signal performance of different SiPM-technologies under irradiation with cold neutrons

    Science.gov (United States)

    Durini, Daniel; Degenhardt, Carsten; Rongen, Heinz; Feoktystov, Artem; Schlösser, Mario; Palomino-Razo, Alejandro; Frielinghaus, Henrich; van Waasen, Stefan

    2016-11-01

    In this paper we report the results of the assessment of changes in the dark signal delivered by three silicon photomultiplier (SiPM) detector arrays, fabricated by three different manufacturers, when irradiated with cold neutrons (wavelength λn=5 Å or neutron energy of En=3.27 meV) up to a neutron dose of 6×1012 n/cm2. The dark signals as well as the breakdown voltages (Vbr) of the SiPM detectors were monitored during the irradiation. The system was characterized at room temperature. The analog SiPM detectors, with and without a 1 mm thick Cerium doped 6Li-glass scintillator material located in front of them, were operated using a bias voltage recommended by the respective manufacturer for a proper detector performance. Iout-Vbias measurements, used to determine the breakdown voltage of the devices, were repeated every 30 s during the first hour and every 300 s during the rest of the irradiation time. The digital SiPM detectors were held at the advised bias voltage between the respective breakdown voltage and dark count mappings repeated every 4 min. The measurements were performed on the KWS-1 instrument of the Heinz Maier-Leibnitz Zentrum (MLZ) in Garching, Germany. The two analog and one digital SiPM detector modules under investigation were respectively fabricated by SensL (Ireland), Hamamatsu Photonics (Japan), and Philips Digital Photon Counting (Germany).

  5. The effect of neutron irradiation on the AlGaN/GaN high electron mobility transistors

    Energy Technology Data Exchange (ETDEWEB)

    Gu, Wenping; Hao, Yue; Yang, Lin' an; Duan, Chao; Duan, Huantao; Zhang, Jincheng; Ma, Xiaohua [School of Microelectronics, Xidian University, China Key Lab of Ministry of Education for Wide Band-Gap Semiconductor Materials and Devices, Xi' an 710071 (China)

    2010-07-15

    The SiN-passivated AlGaN/GaN high electron mobility transistors were investigated by 1MeV neutron irradiation at fluences up to 10{sup 15} cm{sup -2}, yielding a significant degradation for the transconductance near the knee voltage and the reverse gate leakage current at fluences ranging from 10{sup 14} to 10{sup 15} cm{sup -2} which could be attributed to the irradiation induced mobility shift and the defects in SiN passivation layers respectively since no any recovery was found after 20 hour annealing at room temperature. Meanwhile the negligible degradation of the saturation drain current, the maximal transconductance and the threshold voltage gave the fact that the effectiveness of SiN layers in passivated surface states in the source-gate spacer and gate-drain spacer was undiminished by neutron irradiation. Moreover the ohmic contact was robustness to neutron since the sheet resistance of ohmic contact region hardly shifted, but the schottky characteristics degraded obviously. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  6. Feasibility study of U-235, Pu-239 and Pu-240 content determination in an irradiated fuel by neutron transmission analysis

    Energy Technology Data Exchange (ETDEWEB)

    Naguib, K.; Michaiel, M.L.; Morcos, H.N

    1998-07-01

    A proposed nondestructive method and its feasibility for the determination of U-235, Pu-239 and Pu-240 contents in an irradiated fuel is described. The method is based on the use of shape fit analysis of the Time-Of-Flight (TOF) neutron transmission data of the irradiated fuel for neutron energies below 3 eV. The neutron transmission experiment of the irradiated fuel is planned to carry out using one of the TOF spectrometers installed at ET-RR-1 reactor. The computer code SHAPE is adapted taking into account the known parameters of resonances of certain fissile and fission product nuclei to provide the fit analysis. The content of the gross-fissile and fission product isotopes are determined from the burn-up calculations of the fuel assembly of the ET-RR-1 reactor with defined history. The effect of both uncertainties in resonance parameters on the deduced contents of fissile nuclei and statistical accuracy of the TOF measurements are estimated.

  7. Thermal stability and kinetics of defects in magnesium aluminate spinel irradiated with fast neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Yasuda, Kazuhiro E-mail: yasudak@nucl.kyushu-u.ac.jp; Kinoshita, Chiken; Fukuda, Korehisa; Garner, Frank A

    2000-12-01

    Thermal stability of interstitial-type dislocation loops and cavities in single crystals of MgAl{sub 2}O{sub 4} was examined during isochronal and isothermal annealing. The specimens were irradiated with fast-neutrons in FFTF/MOTA at 658 and 1023 K up to 249 dpa. During the isochronal annealing, dislocation loops started to shrink around 1000 K and completely disappeared at 1470 K without changing their character. Cavities grew slightly around 1570 K, and above this temperature, cavities shrunk with increasing annealing temperature. The recovery stage of point defects in MgAl{sub 2}O{sub 4} was discussed in terms of the thermal stability of defect clusters; vacancy migration starts around 1000 K (corresponding to stage III), whereas vacancy clusters start to dissociate around 1570 K (corresponding to stage V). The vacancy migration energy for rate controlling species was estimated from the shrinkage process of interstitial-type dislocation loops to be 2.0 {+-} 0.7 eV.

  8. Application of backscatter electrons for large area imaging of cavities produced by neutron irradiation

    Science.gov (United States)

    Pastukhov, V. I.; Averin, S. A.; Panchenko, V. L.; Portnykh, I. A.; Freyer, P. D.; Giannuzzi, L. A.; Garner, F. A.

    2016-11-01

    It is shown that with proper optimization, backscattered electrons in a scanning electron microscope can produce images of cavity distribution in austenitic steels over a large specimen surface for a depth of ∼500-700 nm, eliminating the need for electropolishing or multiple specimen production. This technique is especially useful for quantifying cavity structures when the specimen is known or suspected to contain very heterogeneous distributions of cavities. Examples are shown for cold-worked EK-164, a very heterogeneously-swelling Russian fast reactor fuel cladding steel and also for AISI 304, a homogeneously-swelling Western steel used for major structural components of light water cooled reactors. This non-destructive overview method of quantifying cavity distribution can be used to direct the location and number of required focused ion beam prepared transmission electron microscopy specimens for examination of either neutron or ion-irradiated specimens. This technique can also be applied in stereo mode to quantify the depth dependence of cavity distributions.

  9. Fracture behavior of neutron-irradiated high-manganese austenitic steels

    Science.gov (United States)

    Yoshida, H.; Miyata, K.; Narui, M.; Kayano, H.

    1991-03-01

    The instrumented Charpy impact test was applied to study the fracture behavior of high-manganese austenitic steels before and after neutron irradiations. Quarter-size specimens of a commercial high-manganese steel (18% Mn-5% Ni-16% Cr), three reference steels (21% Mn-1% Ni-9% Cr, 20% Mn-1% Ni-11% Cr, 15% Mn-1% Ni-13% Cr) and two model steels (17% Mn-4.5% Si-6.5% Cr, 22% Mn-4.5% Si-6.5% Cr-0.2% N) were used for the impact tests at temperatures between 77 and 523 K. The load-deflection curves showed typical features corresponding to characteristics of the fracture properties. The temperature dependences of fracture energy and failure deflection obtained from the curves clearly demonstrate only small effects up to 2 × 10 23 n/m 2 ( E > 0.1 MeV) and brittleness at room temperature in 17% Mn-Si-Cr steel at 1.6 × 10 25 n/m 2 ( E > 0.1 MeV), while ductility still remains in 22%Mn-Si-Cr steel.

  10. Enhancement of flux pinning properties in nanosized MgO added Bi-2212 superconductor through neutron irradiation

    Science.gov (United States)

    Mohiju, Zaahidah'Atiqah; Hamid, Nasri A.; Abdullah, Yusof

    2017-01-01

    For superconducting material to maintain high critical current density, Jc in any applications, effective flux pinning centers are needed. The addition of small size MgO particles in bulk Bi2Sr2CaCu2O8 (Bi-2212) superconductor has been proven to enhance the effective flux pinning centers in the superconducting material by creating a desired microstructure with appropriate defects. To further enhance the pinning properties, radiation is one of the convenient ways to improve the microstructure of the material that has correlation with basic properties of superconductors. Neutron irradiation is one of the niche techniques that can be used to perform the task. Defects with larger radius have dimension comparable to the coherence length of the material and thus improved its superconducting properties. In this paper, a small amount of nanosized MgO particles was used to create defects in the Bi-2212 superconducting material. The Bi-2212/MgO compounds were heat treated, followed by partial melting and slow cooling. Part of the samples was subjected to neutron irradiation using the TRIGA-MARK-II research reactor at the Malaysian Nuclear Agency. Characterization of non-irradiated and irradiated samples was performed via the temperature dependence on electrical resistance measurements, X-ray Diffraction Patterns (XRD), and Scanning Electron Microscopy (SEM) with Energy Dispersive X-ray (EDX) analysis. From the analysis, there was changed in the critical current density and transition temperature of samples subjected to neutron irradiation due to formation of point defects in the microstru