Photoinduced currents in pristine and ion irradiated kapton-H polyimide

Energy Technology Data Exchange (ETDEWEB)

Sharma, Anu, E-mail: sharmaanu81@gmail.com; Sridharbabu, Y., E-mail: sharmaanu81@gmail.com; Quamara, J. K., E-mail: sharmaanu81@gmail.com [Physics Department, SGTB Khalsa college, Delhi University, Delhi (India); Department of Physics, National Institute of Technology, Kurukshetra-136119 (India); Echelon Group of Institutions, Faridabad (India)

2014-10-15

The photoinduced currents in pristine and ion irradiated kapton-H polyimide have been investigated for different applied electric fields at 200°C. Particularly the effect of illumination intensity on the maximum current obtained as a result of photoinduced polarization has been studied. Samples were irradiated by using PELLETRON facility, IUAC, New Delhi. The photo-carrier charge generation depends directly on intensity of illumination. The samples irradiated at higher fluence show a decrease in the peak current with intensity of illumination. The secondary radiation induced crystallinity (SRIC) is responsible for the increase in maximum photoinduced currents generated with intensity of illumination.

Modification of the genetic effect of gamma irradiation by electric current

International Nuclear Information System (INIS)

Grigor'eva, N.N.; Shakhbazov, V.G.

1985-01-01

The authors study the effect of direct current of varying strength and polarity on the genetic damage due to gamma irradiation of Vicia faba seedlings. The modificational effect of direct current observed earlier is confirmed here. The extent and nature of this effect depends on the strength and polarity of the current as well as interval between irradiation and exposure to the electric field. Conditions having no effect on the irradiated seedlings, those protecting the cells from damage and enhancing the irradiation effect, are identified

Charge collection efficiency of irradiated silicon detector operated at cryogenic temperatures

International Nuclear Information System (INIS)

Borer, K.; Janos, S.; Palmieri, V.G.; Dezillie, B.; Li, Z.; Collins, P.; Niinikoski, T.O.; Lourenco, C.; Sonderegger, P.; Borchi, E.; Bruzzi, M.; Pirollo, S.; Granata, V.; Pagano, S.; Chapuy, S.; Dimcovski, Z.; Grigoriev, E.; Bell, W.; Devine, S.R.H.; O'Shea, V.; Smith, K.; Berglund, P.; Boer, W. de; Hauler, F.; Heising, S.; Jungermann, L.; Casagrande, L.; Cindro, V.; Mikuz, M.; Zavartanik, M.; Via, C. da; Esposito, A.; Konorov, I.; Paul, S.; Schmitt, L.; Buontempo, S.; D'Ambrosio, N.; Pagano, S.; Ruggiero, G.; Eremin, V.; Verbitskaya, E.

2000-01-01

The charge collection efficiency (CCE) of heavily irradiated silicon diode detectors was investigated at temperatures between 77 and 200 K. The CCE was found to depend on the radiation dose, bias voltage value and history, temperature, and bias current generated by light. The detector irradiated to the highest fluence 2x10 15 n/cm 2 yields a MIP signal of at least 15000 e - both at 250 V forward bias voltage, and at 250 V reverse bias voltage in the presence of a light-generated current. The 'Lazarus effect' was thus shown to extend to fluences at least ten times higher than was previously studied

Current investigations of packaging materials used for food irradiation

International Nuclear Information System (INIS)

Fiszer, W.

1996-01-01

The article reviews current investigations of packaging materials applied for food irradiation. The increasing role of various synthetic materials is described. Author reviews radiation-induced damages in these materials. The article includes the list of materials accepted for food packaging and subsequent irradiation with different doses

Current status of food irradiation in overseas (2013). From the meeting report of RCA food irradiation project

International Nuclear Information System (INIS)

Todoriki, Setsuko

2013-01-01

The report introduces the activity of RCA (Regional Cooperative Agreement for Research Development and Training Related to Nuclear Science and Technology for Asia and Pacific) food irradiation project (RAS/5/057) and information obtained at the two workshops on current status of Asia and Pacific areas together with EU, USA and Japan. Also current trends of RAS/5/057 Implementing Best Practices for food irradiation for plant sanitary and phytosanitary purposes are described. Amount of food irradiation products of RCA member countries, minimum adopted doses for quarantine harmful insects (70 to 232 Gy) and import amount of fruits of USA (79 to 5500 tons) are tabulated. Finally current status of Japan is explained. (S. Ohno)

Color centers in heavily irradiated CsI(Tl) crystals

International Nuclear Information System (INIS)

Yakovlev, V.; Meleshko, A.; Trefilova, L.

2008-01-01

The absorption and luminescence properties of CsI(Tl) crystals colored by irradiation are studied by the method of the time-resolved spectroscopy. The scheme of the electron transitions in CsI(Tl) crystal is suggested to explain the appearance of the color centers under exposure to the near-UV light. It is established that either of the two types activator color centers holds the charge carrier with opposite sign. The model of the hole Tl 2+ v c - activator color center is suggested. According to the model the positive charge of Tl 2+ ion is compensated by the negative charge of a close cation vacancy v c - . The color center emission reveals in the cathode-luminescence spectrum of the colored CsI(Tl) crystal. The high-dose irradiation of CsI(Tl) crystal results in the reduction of the decay time of the near-thallium self-trapped excitons (STE) emission. The decay kinetics of Tl 2+ v c - emission contains the time components typical for the decay kinetics of near-thallium STE emission. The reason of the observed effects is the energy transfer from the near-thallium STE excitons to the color centers via the inductive-resonant mechanism

Low Current Irradiation Facility at KOMAC

Energy Technology Data Exchange (ETDEWEB)

Min, Yi-Sub; Park, Sung-Kyun; Park, Jeong-Min; Cho, Yong-Sub [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2016-10-15

Korea Multi-purpose Accelerator Complex (KOMAC) is branched off from Korea Atomic Energy Research Institute (KAERI). The 100 MeV linear proton accelerator as well as the various types of the ion accelerator have been operated and developed in KOMAC. The operation of these accelerators included in the KOMAC site should be approved by Nuclear Safety and Security Committee (NSSC). To aims at the operation in 2017, a research facility to irradiate low current beam has been prepared. The radiation safety analysis was performed again to adopt with the change. As a result of these changes, an easy access into the facility will be got to. This paper introduces the activity in terms of the radiation safety for these accelerator operations. Radiation analysis was performed depending on the planned changes, and it was confirmed that there is no effect by the changes. This facility is expected to be made the best use at a field which could be irradiated with proton beam which has an energy up to 100 MeV and current up to 10 nA.

Space-charge-limited currents in electron-irradiated dielectrics

International Nuclear Information System (INIS)

Nunes de Oliveira, L.; Gross, B.

1975-01-01

This paper develops the theory of steady-state currents generated in a dielectric placed between positively or negatively biased electrodes and irradiated with a partially penetrating electron beam. The dielectric is divided into an irradiated region (IR), which extends from the electrode of incidence to the extrapolated range of the beam, and a nonirradiated region (NIR). In the IR the primary beam generates an electron-hole plasma. Its end plane acts as a virtual electrode embedded in the dielectric. Currents are space-charge limited in the NIR and Ohmic in the IR which is characterized by a uniform radiation-induced conductivity. Depending on the polarity of the electrode bias, electrons or holes are drawn from the IR into the NIR. The theory correctly predicts an apparent threshold effect for the inset of steady-state currents: the current amplitudes remain small as long as the electron range is smaller than half the sample thickness, and increase strongly only afterwards. Calculated current curves for different beam energies are in satisfactory agreement with experimental results. The role of the electron beam as a virtual electrode is discussed

Effect of Fast Neutron Irradiation on Current Transport Properties of HTS Materials

CERN Document Server

Ballarino, A; Kruglov, V S; Latushkin, S T; Lubimov, A N; Ryazanov, A I; Shavkin, S V; Taylor, T M; Volkov, P V

2004-01-01

The effect of fast neutron irradiation with energy up to 35 MeV and integrated fluence of up to 5 x 10**15 cm-2 on the current transport properties of HTS materials Bi-2212 and Bi-2223 has been studied, both at liquid nitrogen and at room temperatures. The samples irradiated were selected after verification of the stability of their superconducting properties after temperature cycling in the range of 77 K - 293 K. It has been found that the irradiation by fast neutrons up to the above dose does not produce a significant degradation of critical current. The effect of room temperature annealing on the recovery of transport properties of the irradiated samples is also reported, as is a preliminary microstructure investigation of the effect of irradiation on the soldered contacts.

Measurements of the reverse current of highly irradiated silicon sensors to determine the effective energy and current related damage rate

Science.gov (United States)

Wiehe, Moritz; Wonsak, S.; Kuehn, S.; Parzefall, U.; Casse, G.

2018-01-01

The reverse current of irradiated silicon sensors leads to self heating of the sensor and degrades the signal to noise ratio of a detector. Precise knowledge of the expected reverse current during detector operation is crucial for planning and running experiments in High Energy Physics. The dependence of the reverse current on sensor temperature and irradiation fluence is parametrized by the effective energy and the current related damage rate, respectively. In this study 18 n-in-p mini silicon strip sensors from companies Hamamatsu Photonics and Micron Semiconductor Ltd. were deployed. Measurements of the reverse current for different bias voltages were performed at temperatures of -32 ° C, -27 ° C and -23 ° C. The sensors were irradiated with reactor neutrons in Ljubljana to fluences ranging from 2 × 1014neq /cm2 to 2 × 1016neq /cm2. The measurements were performed directly after irradiation and after 10 and 30 days of room temperature annealing. The aim of the study presented in this paper is to investigate the reverse current of silicon sensors for high fluences of up to 2 × 1016neq /cm2 and compare the measurements to the parametrization models.

Defect formation in heavily doped Si upon irradiation

International Nuclear Information System (INIS)

Gubskaya, V.I.; Kuchinskii, P.V.; Lomako, V.M.

1981-01-01

The rates of the carrier removal and radiation defect introduction into n- and p-Si in the concentration range of 10 14 to 10 17 cm -3 upon 7-MeV-electron irradiation have been studied. The spectrum of the vacancy-type defects, defining the carrier removal rate in lightly doped crystals has been found. With doping level increase the carrier removal rate grows irrespective of conductivity type, and at n 0 , p 0 > 10 17 cm -3 is close to the total displacement number. At the same time a decrease in the introduction rate of the known vacancy-type defects is observed. x It is shown that a considerable growth of the carrier removal rate is defined neither by introduction of shallow compensating centers, nor by change in the primary defect charge state. It is suggested that at high doping impurity concentrations compensation in Si is due to the introduction of complexes doping impurity-interstitial or (impurity atom-interstitial) + vacancy, which give deep levels. (author)

Current status of food irradiation in the world. Trend in Asia

International Nuclear Information System (INIS)

Kume, Tamikazu

2002-01-01

This review describes the current status of food irradiation in the world and particularly, its trends in Asia, based on the report of the economic scale investigation on the irradiation in United States and Japan (2001) and on the information of 12th International Meeting on Radiation Processing in France in 2001 and on personal communications. International Consultative Group on Food Irradiation promotes its activities of irradiation globally and 46 countries are affiliated. Food irradiation is allowed in 52 countries. In 1999, 257,000 t of food is irradiated in the world, of which 1/3 is due to spice. The facilities for the irradiation have such sources as 60 Co and 137 Cs γ-rays, electron beam of <10 MeV and X-ray with <5 MeV. Detection methods of irradiated foods are summarized by the project of Analytical Detection Methods for Irradiation Treatment of Foods. The US is the most advanced country in the irradiation and, in Japan, only irradiation of potato is permitted. The detailed present status is also described of Bangladesh, China (the irradiation is most widely conducted in the world), India, Indonesia, Korea, Malaysia, Thailand and Vietnam. Recently Australia and New Zealand have started the irradiation. (K.H.)

Charge collection properties of heavily irradiated epitaxial silicon detectors

International Nuclear Information System (INIS)

Kramberger, G.; Cindro, V.; Dolenc, I.; Fretwurst, E.; Lindstroem, G.; Mandic, I.; Mikuz, M.; Zavrtanik, M.

2005-01-01

Detectors processed on epitaxial silicon seem to be a viable solution for the extreme radiation levels in the innermost layers of tracking detectors at upgraded LHC (SLHC). A set of epitaxial pad detectors of 50 and 75μm thicknesses (ρ=50Ωcm) was irradiated with 24GeV/c protons and reactor neutrons up to equivalent fluences of 10 16 cm -2 . Charge collection for minimum ionizing electrons from a 90 Sr source was measured using a charge sensitive preamplifier and a 25ns shaping circuit. The dependence of collected charge on annealing time and operation temperature was studied. Results were used to predict the performance of fine pitch pixel detectors proposed for SLHC

Charge collection properties of heavily irradiated epitaxial silicon detectors

Energy Technology Data Exchange (ETDEWEB)

Kramberger, G. [Institute Jozef Stefan, Jamova 39, SI-1111 Ljubljana (Slovenia)]. E-mail: Gregor.Kramberger@ijs.si; Cindro, V. [Institute Jozef Stefan, Jamova 39, SI-1111 Ljubljana (Slovenia); Dolenc, I. [Institute Jozef Stefan, Jamova 39, SI-1111 Ljubljana (Slovenia); Fretwurst, E. [University of Hamburg, Institut fuer Experimentalphysik, Luruper Chaussee 149, D-22761 Hamburg (Germany); Lindstroem, G. [University of Hamburg, Institut fuer Experimentalphysik, Luruper Chaussee 149, D-22761 Hamburg (Germany); Mandic, I. [Institute Jozef Stefan, Jamova 39, SI-1111 Ljubljana (Slovenia); Mikuz, M. [Institute Jozef Stefan, Jamova 39, SI-1111 Ljubljana (Slovenia); Zavrtanik, M. [Institute Jozef Stefan, Jamova 39, SI-1111 Ljubljana (Slovenia)

2005-12-01

Detectors processed on epitaxial silicon seem to be a viable solution for the extreme radiation levels in the innermost layers of tracking detectors at upgraded LHC (SLHC). A set of epitaxial pad detectors of 50 and 75{mu}m thicknesses ({rho}=50{omega}cm) was irradiated with 24GeV/c protons and reactor neutrons up to equivalent fluences of 10{sup 16}cm{sup -2}. Charge collection for minimum ionizing electrons from a {sup 90}Sr source was measured using a charge sensitive preamplifier and a 25ns shaping circuit. The dependence of collected charge on annealing time and operation temperature was studied. Results were used to predict the performance of fine pitch pixel detectors proposed for SLHC.

Density of trapped gas in heavily-irradiated lithium hydride

International Nuclear Information System (INIS)

Bowman, R.C. Jr.; Attalla, A.; Souers, P.C.; Folkers, C.L.; McCreary, T.; Snider, G.D.; Vanderhoofven, F.; Tsugawa, R.T.

1988-01-01

We review old gamma-irradiated lithium hydride data and also display much new bulk and gas-displacement density and nuclear magnetic resonance data on Li(D, T) and LiT at 296 to 373 K. We find that: (1) Li(D, T) swells because of the formation of internal D-T and 3 He gas bubbles, but probably not because of the precipitation of lithium metal; (2) the gas bubbles are at densities of at least 3 to 4x10 4 mol/m 3 , i.e. thousands of atmospheres; (3) outgassing may be largely the result of bubbles rupturing, although diffusion of 3 He as atoms may occur at long times. (orig.)

Charge collection efficiency recovery in heavily irradiated silicon detectors operated at cryogenic temperatures

CERN Document Server

Da Vià, C; Berglund, P; Borchi, E; Borer, K; Bruzzi, Mara; Buontempo, S; Casagrande, L; Chapuy, S; Cindro, V; Dimcovski, Zlatomir; D'Ambrosio, N; de Boer, Wim; Dezillie, B; Esposito, A P; Granat, V; Grigoriev, E; Heijne, Erik H M; Heising, S; Janos, S; Koivuniemi, J H; Konotov, I; Li, Z; Lourenço, C; Mikuz, M; Niinikoski, T O; Pagano, S; Palmieri, V G; Paul, S; Pirollo, S; Pretzl, Klaus P; Ropotar, I; Ruggiero, G; Salmi, J; Seppä, H; Suni, I; Smith, K; Sonderegger, P; Valtonen, M J; Zavrtanik, M

1998-01-01

The charge collection efficiency (CCE) of high resistivity silicon detectors, previously neutron irradiated up to 2*10/sup 15/ n/cm/sup 2/, was measured at different cryogenic temperatures and different bias voltages. In order to $9 study reverse annealing (RA) effects, a few samples were heated to 80 degrees C and kept at room temperature for several months after irradiation. For comparison other samples (NRA) where kept at -10 C after irradiation. The RA and $9 NRA samples, measured at 250 V forward and reverse bias voltage, present a common temperature threshold at 150 K. Below 120 K the CCE is constant and ranges between 55and 65 0.000000or the RA and NRA sample respectively. Similar CCE $9 was measured for a device processed with low resistivity contacts (OHMIC), opening the prospect for a consistent reduction of the cost of large area particle tracking. (7 refs).

Angular and magnetic field dependences of critical current in irradiated YBaCuO single crystals

International Nuclear Information System (INIS)

Petrusenko, Yu.

2010-01-01

The investigation of mechanisms responsible for the current-carrying capability of irradiated high-temperature superconductors (HTSC) was realized. For the purpose, experiments were made to investigate the effect of point defects generated by high-energy electron irradiation on the critical temperature and the critical current in high-Tc superconducting single crystals YBa 2 Cu 3 O 7-x . The transport current density measured in HTSC single crystals YBa 2 Cu 3 O 7-x by the dc-method was found to exceed 80000 A/cm 2 . The experiments have demonstrated a more than 30-fold increase in the critical current density in single crystals irradiated with 2.5 MeV electrons to a dose of 3·10 18 el/cm 2 . Detailed studies were made into the anisotropy of critical current and the dependence of critical current on the external magnetic field strength in irradiated single crystals. A high efficiency of point defects as centers of magnetic vortex pinning in HTSC single crystals was first demonstrated.

Analysis of dark current images of a CMOS camera during gamma irradiation

Energy Technology Data Exchange (ETDEWEB)

Náfrádi, Gábor, E-mail: nafradi@reak.bme.hu [INT, BME, EURATOM Association, H-1111 Budapest (Hungary); Czifrus, Szabolcs, E-mail: czifrus@reak.bme.hu [INT, BME, EURATOM Association, H-1111 Budapest (Hungary); Kocsis, Gábor, E-mail: kocsis.gabor@wigner.mta.hu [Wigner RCP, RMI, EURATOM Association, POB 49, 1525 Budapest (Hungary); Pór, Gábor, E-mail: por@reak.bme.hu [INT, BME, EURATOM Association, H-1111 Budapest (Hungary); Szepesi, Tamás, E-mail: szepesi.tamas@wigner.mta.hu [Wigner RCP, RMI, EURATOM Association, POB 49, 1525 Budapest (Hungary); Zoletnik, Sándor, E-mail: zoletnik.sandor@wigner.mta.hu [Wigner RCP, RMI, EURATOM Association, POB 49, 1525 Budapest (Hungary)

2013-12-15

Highlights: • Radiation tolerance of a fast framing CMOS camera EDICAM examined. • We estimate the expected gamma dose and spectrum of EDICAM with MCNP. • We irradiate EDICAM by 23.5 Gy in 70 min in a fission rector. • Dose rate normalised average brightness of frames grows linearly with the dose. • Dose normalised average brightness of frames follows the dose rate time evolution. -- Abstract: We report on the behaviour of the dark current images of the Event Detection Intelligent Camera (EDICAM) when placed into an irradiation field of gamma rays. EDICAM is an intelligent fast framing CMOS camera operating in the visible spectral range, which is designed for the video diagnostic system of the Wendelstein 7-X (W7-X) stellarator. Monte Carlo calculations were carried out in order to estimate the expected gamma spectrum and dose for an entire year of operation in W7-X. EDICAM was irradiated in a pure gamma field in the Training Reactor of BME with a dose of approximately 23.5 Gy in 1.16 h. During the irradiation, numerous frame series were taken with the camera with exposure times 20 μs, 50 μs, 100 μs, 1 ms, 10 ms, 100 ms. EDICAM withstood the irradiation, but suffered some dynamic range degradation. The behaviour of the dark current images during irradiation is described in detail. We found that the average brightness of dark current images depends on the total ionising dose that the camera is exposed to and the dose rate as well as on the applied exposure times.

High critical currents in heavily doped (Gd,Y)Ba2Cu3Ox superconductor tapes

Energy Technology Data Exchange (ETDEWEB)

Selvamanickam, V; Gharahcheshmeh, MH; Xu, A; Galstyan, E; Delgado, L; Cantoni, C

2015-01-19

REBa2Cu3Ox ((REBCO), RE = rare earth) superconductor tapes with moderate levels of dopants have been optimized for high critical current density in low magnetic fields at 77 K, but they do not exhibit exemplary performance in conditions of interest for practical applications, i.e., temperatures less than 50K and fields of 2-30 T. Heavy doping of REBCO tapes has been avoided by researchers thus far due to deterioration in properties. Here, we report achievement of critical current densities (J(c)) above 20 MA/cm(2) at 30 K, 3 T in heavily doped (25 mol.% Zr-added) (Gd,Y)Ba2Cu3Ox superconductor tapes, which is more than three times higher than the J(c) typically obtained in moderately doped tapes. Pinning force levels above 1000 GN/m(3) have also been attained at 20 K. A composition map of lift factor in J(c) (ratio of J(c) at 30 K, 3 T to the J(c) at 77 K, 0 T) has been developed which reveals the optimum film composition to obtain lift factors above six, which is thrice the typical value. A highly c-axis aligned BaZrO3 (BZO) nanocolumn defect density of nearly 7 x 10(11) cm(-2) as well as 2-3 nm sized particles rich in Cu and Zr have been found in the high J(c) films. (C) 2015 AIP Publishing LLC.

Positron annihilation and thermally stimulated current of electron beam irradiated polyetheretherketone

Energy Technology Data Exchange (ETDEWEB)

Fujita, Shigetaka; Shinyama, Katsuyoshi; Baba, Makoto [Hachinohe Inst. of Tech., Hachinohe, Aomori (Japan); Suzuki, Takenori

1997-03-01

Positron lifetime measurements were applied to electron beam irradiated poly(ether-ether-ketone). The lifetime, {tau}{sub 3}, of the ortho-positronium of unirradiated and 5 MGy irradiated specimen became rapidly longer above about 150degC. {tau}{sub 3} of 50 MGy and 100 MGy irradiated specimen was shorter than that of unirradiated one. Thermally stimulated current (TSC) decreased with increasing the dose before voltage application. In the case of voltage application, a TSC peak appeared and the peak value decreased with increased the dose. The correlation between the results of positron annihilation and TSC was investigated. (author)

Modification of genetic effect of gamma-irradiation by electric current

International Nuclear Information System (INIS)

Grigor'eva, N.N.; Shakhbazov, V.G.

1983-01-01

The effect of direct current of different polarity on genetic sequels of #betta#-radiation of Vicia faba seedlings is studied. It is established that weak current might modify genetic sequels of #betta#-radiation. Protective current effect on irradiated meristem cells of seedlings manifests at negative polarization of the meristem before radiation and at positive polarization-after radiation. Modifying effect of electric current is brought about at the expense of redistribution of anions and cations between the meristem and other root zones

Uranium doping and neutron irradiation of Bi-2223 superconduction tapes for improved critical current density

International Nuclear Information System (INIS)

Moss, S.D.; Wang, W.G.; Dou, S.X.; Weinstein, R.

1998-01-01

It is demonstrated that a combination of neutron irradiation with uranium doping introduce fission tracks through a Bi-2223 tape which act as effective pinning centres, leading to a substantial increase in critical current. Preliminary data suggests that the combination of uranium doping and neutron irradiation produces improved flux pinning in Bi-2223 tapes over neutron irradiation alone. Before irradiation, SEM, DTA and XRD analyses were performed on the tapes. Both before and after irradiation the trapped maximum magnetic flux was measured at 77K. Before neutron irradiation, uranium doping has no effect on critical current. Preliminary SEM data suggested that the uranium is homogeneously distributed throughout the oxide core of the tape. The presence of 2212 and other secondary phases in the doped tapes suggest further refinement of the sintering procedure is necessary. (authors)

High critical currents in heavily doped (Gd,Y)Ba2Cu3Ox superconductor tapes

International Nuclear Information System (INIS)

Selvamanickam, V.; Gharahcheshmeh, M. Heydari; Xu, A.; Galstyan, E.; Delgado, L.; Cantoni, C.

2015-01-01

REBa 2 Cu 3 O x ((REBCO), RE = rare earth) superconductor tapes with moderate levels of dopants have been optimized for high critical current density in low magnetic fields at 77 K, but they do not exhibit exemplary performance in conditions of interest for practical applications, i.e., temperatures less than 50 K and fields of 2–30 T. Heavy doping of REBCO tapes has been avoided by researchers thus far due to deterioration in properties. Here, we report achievement of critical current densities (J c ) above 20 MA/cm 2 at 30 K, 3 T in heavily doped (25 mol. % Zr-added) (Gd,Y)Ba 2 Cu 3 O x superconductor tapes, which is more than three times higher than the J c typically obtained in moderately doped tapes. Pinning force levels above 1000 GN/m 3 have also been attained at 20 K. A composition map of lift factor in J c (ratio of J c at 30 K, 3 T to the J c at 77 K, 0 T) has been developed which reveals the optimum film composition to obtain lift factors above six, which is thrice the typical value. A highly c-axis aligned BaZrO 3 (BZO) nanocolumn defect density of nearly 7 × 10 11  cm −2 as well as 2–3 nm sized particles rich in Cu and Zr have been found in the high J c films

An automated tensile machine for small specimens heavily neutron irradiated in FFTF/MOTA

International Nuclear Information System (INIS)

Kohyama, Akira; Sato, Shinji; Hamada, Kenichi

1993-01-01

The objective of this work is to develop a fully automated tensile machine for post-irradiation examination (PIE) of Fast Flux Test Facility (FFTF)/Materials Open Test Assembly (MOTA) irradiated miniature tension specimens. The anticipated merit of the automated tensile machine is to reduce damage to specimens during specimen handling for PIE and to reduce exposure to radioactive specimens. This machine is designed for testing at elevated temperatures, up to 873 K, in a vacuum or in an inert gas environment. Twelve specimen assemblies are placed in the vacuum chamber that can be tested successively in a fully automated manner. A unique automated tensile machine for the PIE of FFTF/MOTA irradiated specimens, the Monbusho Automated Tensile Machine (MATRON) consists of a test frame with controlling units and an automated specimen-loading apparatus. The qualification of the test frame has been completed, and the results have satisfied the machine specifications. The capabilities of producing creep and relaxation data have been demonstrated for Cu, Al, 316SS, and ferritic steels. The specimen holders for the three-point bending test and the small bulge test (small punch test; SP test) were also designed and produced

The release of stored energy in heavily irradiated NaCl explosive reactions

NARCIS (Netherlands)

Vainshtein, D.; Bemt, M. van den; Seinen, J.; Datema, H.C.; Hartog, H.W. den

1995-01-01

During irradiation of NaCl with ionizing radiation at moderate temperatures (50-150 degrees C) irregular structures of very fine Na and Cl nano-precipitates are formed. The increase of the temperature to a value between 50 and 250 degrees C might induce explosive reactions between radiolytic Na and

Nondestructive examination of irradiated fuel rods by pulsed eddy current techniques

International Nuclear Information System (INIS)

Francis, W.C.; Quapp, W.J.; Martin, M.R.; Gibson, G.W.

1976-02-01

A number of fuel rods and unfueled zircaloy cladding tubes which had been irradiated in the Saxton reactor have undergone extensive nondestructive and corroborative destructive examinations by Aerojet Nuclear Company as part of the Water Reactor Safety Research Program, Irradiation Effects Test Series. This report discusses the pulsed eddy current (PEC) nondestructive examinations on the fuel rods and tubing and the metallography results on two fuel rods and one irradiated zircaloy tube. The PEC equipment, designed jointly by Argonne National Laboratory and Aerojet, performed very satisfactorily the functions of diameter, profile, and wall thickness measurements and OD and ID surface defect detection. The destructive examination provided reasonably good confirmation of ''defects'' detected in the nondestructive examination

Current and potential trade in horticultural products irradiated for phytosanitary purposes

International Nuclear Information System (INIS)

Bustos-Griffin, Emilia; Hallman, Guy J.; Griffin, Robert L.

2012-01-01

The current status of trade in horticultural products irradiated for phytosanitary purposes is examined, including trends, strengths and weaknesses. A strategy is proposed to take advantage of the best future opportunities for increasing trade in irradiated horticultural products by identifying best possibilities for expanding both the number and volume of commodities for irradiation and then applying appropriate business criteria in a general analysis of the commodities, commercial scenarios, and geographic regions where the greatest potential exists for expansion. The results show that fresh fruits such as mango, papaya, citrus, grapes, and vegetables such as tomatoes, onions, asparagus, garlic, and peppers from Asia and the Americas show the greatest potential. Substantial opportunities for additional growth exist, especially as regulatory conditions become more favorable. - Highlights: ► This research examined the trade in horticultural products irradiated for Phytosanitary purposes. ► Paper describes strategies for enhancing trade in irradiated horticultural products. ► Results identify commodities and regions with the greatest potential. ► Additional growth potential exists, especially as regulatory conditions become more favorable.

The influence of gamma irradiation on short-circuit current in CuGaSe2

International Nuclear Information System (INIS)

Gasimoglu, I.; Mamedova, I.A.; Bagirov, A.G.

2005-01-01

Full text : The influence of gamma irradiation on a short-circuit current at 77 K was investigated. The appeared strip with a maximum at 1,61 ///// after irradiation in spectral dependence connected with p-type radiating defects [ru

Cobalt 60 gamma irradiation current status, trends and insights

International Nuclear Information System (INIS)

Corley, John T.

1998-01-01

This paper discusses the current status, trends and insights into the continued, safe use of cobalt 60 gamma irradiation. Also presented are some of the many initiatives undertaken at MDS Nordion. Topics covered include our investment for the future supply of raw materials and the latest news from source production. Briefly presented are the tasks associated with the safe transport of cobalt 60 around the world. Discussed is cobalt 60 usage at the customer site; more specifically maintaining source integrity, source utilization and irradiator design trends. Highlighted are industry trends for North America, Europe and the rest of the world. Finally presented are the challenges and opportunities for the industry. Stressed in the paper is the need to work together

Total body irradiation: current indications; L`irradiation corporelle totale: les indications actuelles

Energy Technology Data Exchange (ETDEWEB)

Giraud, P.; Danhier, S.; Dubray, B.; Cosset, J.M. [Institut Curie, 75 - Paris (France)

1998-05-01

The choice of dose and fractionation for total body irradiation is made difficult by the large number of considerations to be taken into account. The outcome of bone marrow transplantation after total body irradiation can be understood in terms of tumor cell killing, engraftment, and normal tissue damage, each of these endpoints being influenced by irradiation-, disease-, transplant-, and patient- related factors. Interpretation of clinical data is further hampered by the overwhelming influence of logistic constraints, the small numbers of randomized studies, and the concomitant variations in total dose and fraction size or dose rate. So far, three cautious conclusions can be drawn in order to tentatively adapt the total body irradiation schedule to clinically-relevant situations. Firstly, the organs at risk for normal tissue damage (lung, liver, lens, kidney) are protected by delivering small doses per fraction at low dose rate. This suggests that, when toxicity is at stake (e.g. in children), fractionated irradiation should be preferred, provided that inter-fraction intervals are long enough. Secondly, fractionated irradiation should be avoided in case of T-cell depleted transplant, given the high risk of graft rejection in this setting. An alternative would be to increase total (or fractional) dose of fractionated total body irradiation, but this approach is likely to induce more normal tissue toxicity. Thirdly, clinical data have shown higher relapse rates in chronic myeloid leukemia after fractionated or low dose rate total body irradiation, suggesting that fractionated irradiation should not be recommended, unless total (or fractional) dose is increased. Total body irradiation-containing regimens, primarily cyclophosphamide / total body irradiation, are either equivalent to or better than the chemotherapy-only regimens, primarily busulfan / cyclophosphamide. Busulfan / cyclophosphamide certainly represents a reasonable alternative, especially in patients who

Thermally stimulated current method applied to highly irradiated silicon diodes

CERN Document Server

Pintilie, I; Pintilie, I; Moll, Michael; Fretwurst, E; Lindström, G

2002-01-01

We propose an improved method for the analysis of Thermally Stimulated Currents (TSC) measured on highly irradiated silicon diodes. The proposed TSC formula for the evaluation of a set of TSC spectra obtained with different reverse biases leads not only to the concentration of electron and hole traps visible in the spectra but also gives an estimation for the concentration of defects which not give rise to a peak in the 30-220 K TSC temperature range (very shallow or very deep levels). The method is applied to a diode irradiated with a neutron fluence of phi sub n =1.82x10 sup 1 sup 3 n/cm sup 2.

Current status of food irradiation in Korea

International Nuclear Information System (INIS)

Kwon, Joong-Ho

2007-01-01

With respect to the safety of irradiated food, the Korean government has accepted in principle the recommendations of international organization (FAO, WHO, IAEA, CAC, etc) as well as the national-based evaluations. Gamma radiation from Co-60 is now authorized to be used for food irradiation of 26 food items (or classes). Two multipurpose gamma-irradiation facilities (Greenpia Tech. Inc. since 1987; SOYA Co. Ltd. since 2002) are now operating for the treatments of selected food items as well as medical supplies. At present, labeled-irradiated products are not yet being marketed at the consumer level. As an alternative process of chemical fumigants, however, irradiation is being partially utilized for the microbial decontamination and pest control of dried spices, vegetable ingredients, etc. for their use in processed foods as minor ingredients. Commercial applications of food irradiation, though small in number, have been steady ever since. This article introduces the commercial progress in food irradiation technology in Korea in terms of research activities, legislation, commercialization, and the control of irradiated foods. (author)

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.

Ion-channeling analysis of As relocation in heavily doped Si:As irradiated with high-energy ions

International Nuclear Information System (INIS)

Lulli, G.; Albertazzi, E.; Bianconi, M.; Ferri, M.

2003-01-01

Silicon on insulator layers doped with 8x10 20 As cm -3 and thermally equilibrated at 1100 deg. C, have been irradiated with 2 MeV Si + ions. Rutherford backscattering-channeling analysis shows an increase in As disorder upon irradiation significantly larger than the increase in Si disorder, while electrical measurements show a large decrease in electrical activation. Monte Carlo simulation of channeling angular scans suggests that the enhanced As disorder effect is due to the preferential relocation of dopant atoms slightly displaced from lattice sites, which appear the main reason responsible for the electrical deactivation in the unirradiated sample and are believed to be in the form of As-vacancy clusters. Upon 600 deg. C 15 s annealing, the As atoms randomly relocated by ion irradiation almost completely recover their original configuration, probably capturing vacancies and forming, again, the complexes dissociated by ion irradiation

Simulation of tensile stress-strain properties of irradiated type 316 SS by heavily cold-worked material

International Nuclear Information System (INIS)

Muto, Yasushi; Jitsukawa, Shiro; Hishinuma, Akimichi

1995-07-01

Type 316 stainless steel is one of the most promising candidate materials to be used for the structural parts of plasma facing components in the nuclear fusion reactor. The neutron irradiation make the material brittle and reduces its uniform elongation to almost zero at heavy doses. In order to apply such a material of reduced ductility to structural components, the structural integrity should be examined and assured by the fracture mechanics. The procedure requires a formulated stress-strain relationship. However, the available irradiated tensile test data are very limited at present, so that the cold-worked material was used as a simulated material in this study. Property changes of 316 SS, that is, a reduction of uniform elongation and an enhancement of yield stress are seemingly very similar for both the irradiated 316 SS and the cold-worked one. The specimens made of annealed 316 SS, 20% (or 15%) cold worked one and 40% cold worked one were prepared. After the formulation of stress strain behavior, the equation for the cold-worked 316 SS was fitted to the data on irradiated material under the assumption that the yield stress is the same for both materials. In addition, the upper limit for the plastic strain was introduced using the data on the irradiated material. (author)

Characterization of irradiated fuel rods using pulsed eddy current techniques

International Nuclear Information System (INIS)

Martin, M.R.; Francis, W.C.

1975-11-01

A number of irradiated fuel rods and unfueled zircaloy cladding tubes (''water tubes'') were obtained from the Saxton reactor through arrangements with the Westinghouse Electric Corporation for use in subsequent irradiation effects and fuel behavior programs. A comprehensive nondestructive and corroborative destructive characterization program was undertaken on these fuel rods and tubes by ANC to provide baseline data on their characteristics prior to further testing and for comparison against post-post data. This report deals primarily with one portion of the NDT program performed remotely in the hot cells. The portion of interest in this paper is the pulsed eddy current inspection used in the nondestructive phase of the work. 6 references

Influence of 2 MeV electrons irradiation on gallium phosphide light-emitting diodes reverse currents

Directory of Open Access Journals (Sweden)

V. G. Vorobiov

2015-10-01

Full Text Available Results of reverse electrophysical characteristics study of red and green LEDs, initial and irradiated with 2 MeV electrons were given. It was found that reverse current was predominantly caused by carriers tunneling at Urev ≤ 9 V, and by the avalanche multiplication at Urev ≥ 13 V, in the range U = 9 ÷ 13 V both mechanisms are available. Current increase at high voltage areas (Urev > 19 V is limited by the base resistance of diode. In the case of significant reverse currents (I > 1 mA irradiation of diodes leads to the shift of reverse current-voltage characteristics into the high voltages direction.

Review of current summary of irradiated foods

International Nuclear Information System (INIS)

Dyakova, A.; Tsvetkova, E.; Miteva, D.; Dimov, K.

2005-01-01

The reasons about widely application of food irradiation as a technology for increasing food safety were presenting in this summary. Topics which are discussing are about: purpose of the irradiation, radiological safety, toxicology, microbiological conclusion, alimentary adequacy, packing, labeling, public acceptance, inspection of food irradiated plants

Phytosanitary irradiation of fresh tropical commodities in Hawaii: Generic treatments, commercial adoption, and current issues

International Nuclear Information System (INIS)

Follett, Peter A.; Weinert, Eric D.

2012-01-01

Hawaii is a pioneer in the use of phytosanitary irradiation. The commercial X-ray irradiation facility, Hawaii Pride LLC, has been shipping papaya and other tropical fruits and vegetables to the United States mainland using irradiation for 11 years. Irradiation is an approved treatment to control quarantine pests in 17 fruits and 7 vegetables for export from Hawaii to the US mainland. Hawaiian purple sweet potato is the highest volume product with annual exports of more than 12 million lbs (5500 t). The advent of generic radiation treatments for tephritid fruit flies (150 Gy) and other insects (400 Gy) will accelerate commodity export approvals and facilitate worldwide adoption. Lowering doses for specific pests and commodities can lower treatment costs and increase capacity owing to shorter treatment times, and will minimize any quality problems. Current impediments to wider adoption include the 1 kGy limit for fresh horticultural products, the labeling requirement, and non-acceptance of phytosanitary irradiation in Japan, the European Union, and elsewhere. Irradiation has potential as a treatment for unregulated imports to prevent new pest incursions. - Highlights: ► Irradiation is used to control quarantine insects in exported fresh commodities. ► Hawaii exported 5.7 t of tropical produce using irradiation in 2010. ► Generic radiation treatments will accelerate commodity export approvals. ► Lowering the dose for specific commodities will reduce costs/maintain quality. ► Current issues include the 1 kGy dose limit and labeling requirements.

Characterization of as-grown and heavily irradiated GaN epitaxial structures by photoconductivity and photoluminescence

International Nuclear Information System (INIS)

Gaubas, E.; Jurs e-dot nas, S.; Tomasiunas, R.; Vaitkus, J.; Zukauskas, A.; Blue, A.; Rahman, M.; Smith, K.M.

2005-01-01

The influence of radiation defects on photoconductivity transients and photoluminescence (PL) spectra have been examined in semi-insulating GaN epitaxial layers grown on bulk n-GaN/sapphire substrates. Defects induced by 10-keV X-ray irradiation with a dose of 600Mrad and 100-keV neutrons with fluences of 5x10 14 and 10 16 cm -2 have been revealed through contact photoconductivity and microwave absorption transients. The amplitude of the initial photoconductivity decay is significantly reduced by the radiation defect density. A simultaneous decrease with radiation-induced defect density is also observed in the steady-state PL intensity of yellow, blue and ultraviolet bands peaked at 2.18, 2.85, and 3.42eV, respectively. The decrease of the PL intensity is accompanied by an increase of asymptotic decay lifetime, which is due to excess carrier multi-trapping. The decay can be described by the stretched exponential approximation exp[-(t/τ) α ] with different values of α in as-grown material (α∼0.7) and irradiated samples (α∼0.3). The value of the fracton dimension d s of the disordered structure, evaluated as d s =2α/(1-α), changes from 4.7 to 0.86 for as-grown and irradiated material, respectively, implying percolative carrier motion on an infinite cluster of dislocations net in the as-grown material and cluster fragmentation into finite fractons after irradiation

Is current clinical practice modified about intraoperative breast irradiation?

Science.gov (United States)

Massa, Michela; Franchelli, Simonetta; Panizza, Renzo; Massa, Tiberio

2016-04-01

After the results obtained in the two randomized clinical trial, the ELIOT trial and the TARGIT-A trial, a heated debate is going on concerning the question of applying intraoperative radiotherapy (IORT) instead of postoperative whole breast irradiation (WBI) after breast conservative treatment. Currently, many centers are applying the IORT following the strict selection criteria dictated by the working groups American Society for Radiation Oncology (ASTRO) and Groupe Européen de Curiethérapie-European Society for Therapeutic Radiology and Oncology (GEC-ESTRO) and monitoring the oncological outcome together with radiation toxicity on breast tissue. The clinical experience of the Geneva University Hospital regarding the use of the Intrabeam system is evaluated and compared with current evidences.

Effect of irradiation on the critical currents of alloy and compound superconductors

International Nuclear Information System (INIS)

Sekula, S.T.

1977-06-01

The effects of energetic-particle irradiation on the critical-current density J/sub c/(H) of several superconducting compounds and Nb-Ti alloys have been examined by a number of workers. The irradiations used in the investigations include electrons, fast neutrons, ions, and fission fragments. The results of these studies are reviewed and summarized. In the alloys, changes in J/sub c/(H) on irradiation depend on the metallurgical history of the material and indicate that radiation defects modify the strength of the interaction between the fluxoid array and the sample microstructure. Radiation defects in alloys can also affect J/sub c/(H) through small decreases in T/sub c/, the transition temperature and rho, the normal-state resistivity. Irradiations of A15 compounds up to moderate fluences (dependent on the type and energy of irradiating particle) lead to decreases in T/sub c/ of approximately 1 0 K and increases in J/sub c/(H) with dose for most of the samples investigated. This result can be qualitatively understood as resulting from radiation-induced changes in rho and the pinning force acting on the fluxoids. At higher dose levels, significant depressions of T/sub c/ and possibly gamma, the electronic specific heat coefficient, lead to drastic reductions in J/sub c/(H). The effect of various energetic particles and irradiation temperature on changes in J/sub c/(H) are discussed

Ionising radiation dosimetry by measuring thermally excited currents (TEC) in irradiated highpolymers

International Nuclear Information System (INIS)

Shtol'ts, V.; Petermann, V.; Nigot, V.

1976-01-01

The first results are presented in measuring thermally excited currents (TEC) in 60 Co - gamma irradiated polyethylene and teflon. The design of measuring instruments is described. The maximum background currents in nonirradiated samples reached 10 -13 A. The TEC curves are presented which have obtained under irradiation up to 0.1-1000 rad followed by heating in the temperature range from 20 to 250 deg C. The curves exhibited maxima at about 90 deg C for polyethylene and about 200 deg C for teflon. The TEC dose range has been determined to be 0.1-1000 rad and 5-1000 rad for polyethylene and teflon, respectively. The fading at room temperature after 100 hrs has appeared to be 50% for polyethylene and 60% for teflon. The main merit of the technique is assumed to be the simplicity of the measuring instruments [ru

Current state of waste and food irradiation

International Nuclear Information System (INIS)

Horacek, P.

1979-01-01

Research and industrial applications are briefly described of irradiation technology in Czechoslovakia and in other countries. Intensive research into the irradiation of meat, grain, fruit and vegetables is going on; it has not, however, been widely applied in practice. The objective of the research into industrial and agricultural waste irradiation is to make the wastes usable as fertilizers or feed additives for farm animals. (M.S.)

Various categories of defects after surface alloying induced by high current pulsed electron beam irradiation

Energy Technology Data Exchange (ETDEWEB)

Luo, Dian [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Tang, Guangze, E-mail: oaktang@hit.edu.cn [School of Material Science & Engineering, Harbin Institute of Technology, Harbin 150001 (China); Ma, Xinxin [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Gu, Le [School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001 (China); Sun, Mingren [School of Material Science & Engineering, Harbin Institute of Technology, Harbin 150001 (China); Wang, Liqin [School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001 (China)

2015-10-01

Highlights: • Four kinds of defects are found during surface alloying by high current electron beam. • Exploring the mechanism how these defects appear after irradiation. • Increasing pulsing cycles will help to get good surface quality. • Choosing proper energy density will increase surface quality. - Abstract: High current pulsed electron beam (HCPEB) is an attractive advanced materials processing method which could highly increase the mechanical properties and corrosion resistance. However, how to eliminate different kinds of defects during irradiation by HCPEB especially in condition of adding new elements is a challenging task. In the present research, the titanium and TaNb-TiW composite films was deposited on the carburizing steel (SAE9310 steel) by DC magnetron sputtering before irradiation. The process of surface alloying was induced by HCPEB with pulse duration of 2.5 μs and energy density ranging from 3 to 9 J/cm{sup 2}. Investigation of the microstructure indicated that there were several forms of defects after irradiation, such as surface unwetting, surface eruption, micro-cracks and layering. How the defects formed was explained by the results of electron microscopy and energy dispersive spectroscopy. The results also revealed that proper energy density (∼6 J/cm{sup 2}) and multi-number of irradiation (≥50 times) contributed to high quality of alloyed layers after irradiation.

Particle-in-cell simulation of electron trajectories and irradiation uniformity in an annular cathode high current pulsed electron beam source

Energy Technology Data Exchange (ETDEWEB)

Jiang, Wei; Wang, Langping, E-mail: aplpwang@hit.edu.cn; Zhou, Guangxue; Wang, Xiaofeng

2017-02-01

Highlights: • The transmission process of electrons and irradiation uniformity was simulated. • Influence of the irradiation parameters on irradiation uniformity are discussed. • High irradiation uniformity can be obtained in a wide processing window. - Abstract: In order to study electron trajectories in an annular cathode high current pulsed electron beam (HCPEB) source based on carbon fiber bunches, the transmission process of electrons emitted from the annular cathode was simulated using a particle-in-cell model with Monte Carlo collisions (PIC-MCC). The simulation results show that the intense flow of the electrons emitted from the annular cathode are expanded during the transmission process, and the uniformity of the electron distribution is improved in the transportation process. The irradiation current decreases with the irradiation distance and the pressure, and increases with the negative voltage. In addition, when the irradiation distance and the cathode voltage are larger than 40 mm and −15 kV, respectively, a uniform irradiation current distribution along the circumference of the anode can be obtained. The simulation results show that good irradiation uniformity of circular components can be achieved by this annular cathode HCPEB source.

The Defect Inspection on the Irradiated Fuel Rod by Eddy Current Test

International Nuclear Information System (INIS)

Koo, D. S.; Park, Y. K.; Kim, E. K.

1996-01-01

The eddy current test(ECT) probe of differential encircling coil type was designed and fabricated, and the optimum condition of ECT was derived for the examination of the irradiated fuel rod. The correlation between ECT test frequency and phase and amplitude was derived by performing the test of the standard rig that includes inner notches, outer notches and through-holes. The defect of through-hole was predicted by ECT at the G33-N2 fuel rod irradiated in the Kori-1 nuclear power reactor. The metallographic examination on the G33-N2 fuel rod was Performed at the defect location predicted by ECT. The result of metallographic examination for the G33-N2 fuel rod was in good agreement with that of ECT. This proves that the evaluation for integrity of irradiated fuel rod by ECT is reliable

Band to Band Tunneling (BBT) Induced Leakage Current Enhancement in Irradiated Fully Depleted SOI Devices

Science.gov (United States)

Adell, Phillipe C.; Barnaby, H. J.; Schrimpf, R. D.; Vermeire, B.

2007-01-01

We propose a model, validated with simulations, describing how band-to-band tunneling (BBT) affects the leakage current degradation in some irradiated fully-depleted SOI devices. The dependence of drain current on gate voltage, including the apparent transition to a high current regime is explained.

Preservation of crab meat by gamma irradiation

International Nuclear Information System (INIS)

Loaharanu, P.; Prompubesara, C.; Kraisorn, K.; Noochpramool, K.

1972-01-01

Fresh crab meat from swimming crab (Portunus pelagicus, Linn.) was irradiated at doses of 0.075, 0.15 and 0.25 Mrad and held at 3 0 C. The storage life of non-irradiated crab meat was approximately 7 days compared with 14 days for crab meat irradiated at 0.075 Mrad and 28 days for samples receiving 0.15 or 0.25 Mrad treatment. Total aerobic count, trimethylamine nitrogen, total volatile basic nitrogen, and ammonia contents were used as objective indices of freshness in comparison with sensory evaluation of the crab meat. All objective indices correlated well with the sensory judgement of the samples. The crab meat used in the study was heavily contaminated with microorganisms. Irradiation at 0.15 and 0.25 Mrad reduced approximately 2 log cycles in the total count. Acinetobacter (Achromobacter) was predominated in irradiated crab meat, especially after prolonged storage. High coagulase positive staphylococci count was detected in only non-irradiated crab meat

Current status of information transfer activity on food irradiation and consumer attitudes in Japan

Science.gov (United States)

Furuta, Masakazu

2004-09-01

For the purpose of public education of radiation and radiation-related technology towards school kids and their parents through efficient information transfer, ''RADIATION FAIR—the relationship between daily life and radiation" has been successfully held at Kintetsu Department Store, one of the major departmental stores in downtown Osaka, the second largest city in Japan during summer vacation in every August for 19 years. Currently various irradiated products available in our daily life including irradiated potatoes and spices were displayed together with explanatory panels and attractions. The number of participants has increased every year and constantly exceeded 20,000 in recent years. This activity has become a good medium for the consumer to recognize the quality of the irradiated potatoes which has been distributed in the market since 1974, and irradiated spices, the next candidate for the clearance under examination by Japanese government. Taking advantage of this opportunity, we have demonstrated toward the participants that irradiation-decontaminated spices are superior to conventional heat-treated ones in aromatic quality as well as conducting survey of the visitor's feeling on radiation and irradiated foods. These activities would be potentially effective to facilitate public acceptance of irradiation decontamination of spices.

Current status of information transfer activity on food irradiation and consumer attitudes in Japan

International Nuclear Information System (INIS)

Furuta, Masakazu

2004-01-01

For the purpose of public education of radiation and radiation-related technology towards school kids and their parents through efficient information transfer, 'RADIATION FAIR - the relationship between daily life and radiation' has been successfully held at Kintetsu Department Store, one of the major departmental stores in downtown Osaka, the second largest city in Japan during summer vacation in every August for 19 years. Currently various irradiated products available in our daily life including irradiated potatoes and spices were displayed together with explanatory panels and attractions. The number of participants has increased every year and constantly exceeded 20,000 in recent years. This activity has become a good medium for the consumer to recognize the quality of the irradiated potatoes which has been distributed in the market since 1974, and irradiated spices, the next candidate for the clearance under examination by Japanese government. Taking advantage of this opportunity, we have demonstrated toward the participants that irradiation-decontaminated spices are superior to conventional heat-treated ones in aromatic quality as well as conducting survey of the visitor's feeling on radiation and irradiated foods. These activities would be potentially effective to facilitate public acceptance of irradiation decontamination of spices

Scanning transient current study of the I-V stabilization phenomena in silicon detectors irradiated by fast neutrons

International Nuclear Information System (INIS)

Eremin, V.; Verbitskaya, E.; Sidorov, A.; Fretwurst, E.; Lindstrom, G.

1996-03-01

Investigation of the I-V stabilization phenomena in neutron irradiated silicon detectors has been carried out using scanning transient current technique (STCT) on non-irradiated PP + -p-n + detectors. The PP + -p-n + detectors were used to simulate the PP + -n-n + detectors irradiated beyond the space charge sign inversion (SCSI). Two mechanisms partially responsible for the I- V stabilization have been identified

Irradiated foods

International Nuclear Information System (INIS)

Darrington, Hugh

1988-06-01

This special edition of 'Food Manufacture' presents papers on the following aspects of the use of irradiation in the food industry:- 1) an outline view of current technology and its potential. 2) Safety and wholesomeness of irradiated and non-irradiated foods. 3) A review of the known effects of irradiation on packaging. 4) The problems of regulating the use of irradiation and consumer protection against abuse. 5) The detection problem - current procedures. 6) Description of the Gammaster BV plant in Holland. 7) World outline review. 8) Current and future commercial activities in Europe. (U.K.)

Current status of information transfer activity on food irradiation and consumer attitudes in Japan

Energy Technology Data Exchange (ETDEWEB)

Furuta, Masakazu E-mail: mfuruta@riast.osakafu-u.ac.jp

2004-10-01

For the purpose of public education of radiation and radiation-related technology towards school kids and their parents through efficient information transfer, 'RADIATION FAIR - the relationship between daily life and radiation' has been successfully held at Kintetsu Department Store, one of the major departmental stores in downtown Osaka, the second largest city in Japan during summer vacation in every August for 19 years. Currently various irradiated products available in our daily life including irradiated potatoes and spices were displayed together with explanatory panels and attractions. The number of participants has increased every year and constantly exceeded 20,000 in recent years. This activity has become a good medium for the consumer to recognize the quality of the irradiated potatoes which has been distributed in the market since 1974, and irradiated spices, the next candidate for the clearance under examination by Japanese government. Taking advantage of this opportunity, we have demonstrated toward the participants that irradiation-decontaminated spices are superior to conventional heat-treated ones in aromatic quality as well as conducting survey of the visitor's feeling on radiation and irradiated foods. These activities would be potentially effective to facilitate public acceptance of irradiation decontamination of spices.

Effects of vacuum ultraviolet irradiation on trapped charges and leakage currents of low-k organosilicate dielectrics

Energy Technology Data Exchange (ETDEWEB)

Zheng, H.; Guo, X.; Pei, D.; Shohet, J. L. [Plasma Processing and Technology Laboratory and Department of Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Ryan, E. T. [GLOBALFOUNDRIES, Albany, New York 12203 (United States); Nishi, Y. [Stanford University, Stanford, California 94305 (United States)

2015-05-11

Vacuum ultraviolet (VUV) photoemission spectroscopy is utilized to investigate the distribution of trapped charges within the bandgap of low dielectric constant (low-k) organosilicate (SiCOH) materials. It was found that trapped charges are continuously distributed within the bandgap of porous SiCOH and the center of the trapped states is 1.3 eV above the valence band of the tested sample. By comparing photoemission spectroscopic results before and after VUV exposure, VUV irradiation with photon energies between 7.6 and 8.9 eV was found to deplete trapped charge while UV exposure with photon energies less than 6.0 eV induces more trapped charges in tested samples. Current-Voltage (IV) characteristics results show that the reliability of dielectrics is improved after VUV irradiation with photon energies between 7.6 and 8.9 eV, while UV exposure results in an increased level of leakage current and a decreased breakdown voltage, both of which are harmful to the reliability of the dielectric. This work shows that VUV irradiation holds the potential to substitute for UV curing in microelectronic processing to improve the reliability of low-k dielectrics by mitigating the leakage currents and trapped charges induced by UV irradiation.

Enhancements of the critical currents of YBaCuO single crystals by neutron (n) and proton (p) irradiation

International Nuclear Information System (INIS)

Vlcek, B.M.; Frischherz, M.C.; Vishwanathan, H.K.; Welp, U.; Crabtree, G.W.; Kirk, M.A.

1992-01-01

We present results of magnetization hysteresis and T c measurements of neutron and proton irradiated YBaCuO single crystals. The crystals used for comparison were irradiated to a fluence of 2x10 7 n/cm 2 (n,E > 0.1MeV) and 1x10 16 p/cm 2 (p,E=3.5MeV). The critical currents at 1T and 10K are enhanced by a factor of 5 for the neutron irradiated and a factor of 9 for the proton irradiated sample respectively. After irradiation the crystals were annealed at 100, 200 and 300C for 8h each in air. Following each annealing step the critical temperature and the magnetization hysteresis at 10 and 70K was measured. Upon annealing, we observe a decrease of the critical currents, which is more pronounced for the proton irradiated sample. This decrease is related to the removal of point defects or their small clusters. Thus, their contribution to pinning can be studied. The critical temperature decreases after both types of irradiation by about 0.5K and is fully recovered after annealing

Electrical characterization of FBK small-pitch 3D sensors after γ-ray, neutron and proton irradiations

Science.gov (United States)

Dalla Betta, G.-F.; Boscardin, M.; Hoeferkamp, M.; Mendicino, R.; Seidel, S.; Sultan, D. M. S.

2017-11-01

In view of applications in the tracking detectors at the High Luminosity LHC (HL-LHC), we have developed a new generation of 3D pixel sensors featuring small-pitch (50 × 50 or 25 × 100 μ m2) and thin active layer (~ 100 μ m). Owing to the very short inter-electrode distance (~ 30 μ m), charge trapping effects can be strongly mitigated, making these sensors extremely radiation hard. However, the downscaled sensor structure also lends itself to high electric fields as the bias voltage is increased, motivating investigation of leakage current increase in order to prevent premature electrical breakdown due to impact ionization. In order to assess the characteristics of heavily irradiated samples, using 3D diodes as test devices, we have carried out a dedicated campaign that included several irradiations (γ -rays, neutrons, and protons) at different facilities. In this paper, we report on the electrical characterization of a subset of the irradiated samples, also in comparison to their pre-irradiation properties. Results demonstrate that hadron irradiated devices can be safely operated at a voltage high enough to allow for full depletion (hence high efficiency) also at the maximum fluence foreseen at the HL-LHC.

Ultraviolet irradiation disrupts somatic pili structure and function

Energy Technology Data Exchange (ETDEWEB)

Silverblatt, F.J.

1979-09-01

Three piliated bacterial species were exposed to ultraviolet light and the effect of increasing duration of irradiation on the integrity of the somatic pili was quantitated by negative-stain electron microscopy. Heavily piliated Proteus mirabilis became devoid of pili after 20 min of irradiation, but Escherichia coli and Neisseria gonorrhoeae required 40 min for complete depiliation. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis demonstrated that new, small molecular weight fragments appeared after irradiation of purified E. coli pili, suggesting that cleavage of the peptide chain rather than dissociation of pilin monomers accounted for the loss of pili structure. These observations indicate that the ultrastructural integrity and function of pili can be disrupted by ultraviolet light.

Pollination with gamma-irradiated pollen and seed development in kiwifruit (Actinidia deliciosa var. deliciosa)

International Nuclear Information System (INIS)

Musial, K.

1997-01-01

Full text. The effects of pollen irradiation at 70 and 90 kr on seed set were studied in Actinidia deliciosa var. deliciosa. Pollination with irradiated pollen affected seed development and contents. Rising irradiation doses increased the percentages of empty seeds and decreased the percentages of seeds containing embryos with endosperm. Moreover, pollination with heavily irradiated pollen led to the formation of seeds containing the endosperm only. Embryo and endosperm size was also strongly influenced by irradiated pollen. The length of endosperms was reduced at all levels of pollen irradiation compared to the non-irradiated controls; the embryo development was conspicuously retarded. Cells in endosperm resulting from the treatments differed in the presence and number of starch grains. (author)

Further considerations for damping in heavily insulated pipe systems

International Nuclear Information System (INIS)

Anderson, M.J.; Lindquist, M.R.; Severud, L.K.

1985-01-01

Over the past several years a body of test data has been accumulated which demonstrates that damping in small diameter heavily insulated pipe systems is much larger than presently recommended by Regulatory Guide 1.61. This data is generally based on pipe systems using a stand-off insulation design with a heater annulus. Additional tests have how been completed on similar pipe systems using a strap-on insulation design without the heater annulus. Results indicate some reduction in damping over the stand-off designs. Test data has also been obtained on a larger sixteen-inch diameter heavily insulated pipe system. Results of these two additional test series are presented. Revised damping values for seismic design of heavily insulated pipe systems are then recommended

Further considerations for damping in heavily insulated pipe systems

International Nuclear Information System (INIS)

Anderson, M.J.; Lindquist, M.R.; Severud, L.K.

1985-01-01

Over the past several years a body of test data has been accumulated which demonstrates that damping in small diameter heavily insulated pipe systems is much larger than presently recommended by Regulatory Code 1.61. This data is generally based on pipe systems using a stand-off insulation design with a heater annulus. Additional tests have now been completed on similar pipe systems using a strap-on insulation design without the heater annulus. Results indicate some reduction in damping over the stand-off designs. Test data has also been obtained on a larger sixteen-inch diameter heavily insulated pipe system. Results of these two additional test series are presented. Revised damping values for seismic design for heavily insulated pipe systems are then recommended

Phytosanitary irradiation for export of fresh produce. Commercial adoption in Hawaii and current issues

International Nuclear Information System (INIS)

Follett, P.A.; Wall, M.M.

2013-01-01

Hawaii is a pioneer in the use of phytosanitary irradiation. Irradiation is an approved treatment to control quarantine insect pests in 17 fruits and 7 vegetables for export from Hawaii to the US mainland. The commercial X-ray irradiation facility, Hawaii Pride LLC, has been shipping tropical fruits and vegetables to the US mainland using irradiation since 2000. Hawaiian purple sweet potato is the highest volume product with annual exports of more than 12 million lbs (5,500 tonnes). The advent of generic radiation treatments for tephritid fruit flies (150 Gy) and other insects (400 Gy) has accelerated commodity export approvals and facilitated adoption by foreign trading partners. Current impediments to wider adoption include the labeling requirement, the 1 kGy limit for fresh horticultural products, and non-acceptance of phytosanitary irradiation in Japan and the European Union. USDA Animal and Plant Health Inspection Service (APHIS) has restricted the use of modified atmosphere packaging (MAP) for irradiated fresh fruits exported to the US due to possible increased radio-tolerance in the target insects. Data are presented for response of melon fly in papaya to several types of MAP with radiation treatment at 45-65 Gy. Low oxygen atmospheres can increase insect radio-tolerance, but the effect is dependent on oxygen concentration and radiation dose. (author)

Comparative characteristic of transmembrane currents and caffeine-induced responses of intact and irradiated small intestine smooth muscle cells

International Nuclear Information System (INIS)

Stepanov, Yu.V.; Gordienko, D.V.; Preobrazhenskaya, T.D.; Stepanova, L.I.; Vojtsitskij, V.M.

1994-01-01

A comparative investigation of transmembrane ion currents and caffeine-induced responses of single smooth muscle cells isolated from the circular layer of rat small intestine was curried out by the method of 'patch-clamp'. No reliable difference in potential-dependent and amplitude-kinetic characteristics of transmembrane ion currents in cells of intact and irradiated with dose of 3 Gy rats was revealed. In cells of irradiated animals external application of caffeine (4 mM) was not accompanied by strong quick-inactivated transient Ca 2+ -dependent potassium current as in control

TOSCA simulation of some effects observed in irradiated silicon detectors

International Nuclear Information System (INIS)

Moszczynski, A.S.

2001-12-01

TOSCA package has been used to simulate some effects observed recently in heavily irradiated silicon detectors. In particular, unexpected possibility of α-particle registration at p+ contact has been explained without presented elsewhere assumption that there was p-n junction of unknown origin beneath p+ layer. Performed simulations showed that assumption on relaxation-like character of irradiated silicon material is also not necessary to explain such effects like low-voltage capacitance peak in reverse bias and negative capacitance in forward bias. (author)

Experimental Irradiations of Materials and Fuels in the BR2 Reactor: An Overview of Current Programmes

International Nuclear Information System (INIS)

Van Dyck, S.; Koonen, E.; Verwerft, M.; Wéber, M.

2013-01-01

The BR2 material test reactor offers a variety of experimental irradiation possibilities for testing of materials, fuels and instruments. The current paper gives an overview of the recent and ongoing programmes in order to illustrate the experimental potential of the reactor. Three domains of applications are reviewed: Irradiation of materials and fuels for pressurised water reactors (PWR); irradiation of materials for accelerator driven systems (ADS), cooled by liquid lead alloys; and irradiation of fuel for Material Test Reactors (MTR). For PWR relevant tests, a dedicated loop is available, providing a full simulation of the thermo hydraulic conditions of a PWR. ADS related tests require particular control of the irradiation environment and the necessary safety precautions in order to avoid 210 Po contamination. In-core mechanical testing of materials is done in comparison and complimentarily to post-irradiation examinations in order to assess flux related effects on the deformation behaviour of materials. (author)

Investigation of leakage current and breakdown voltage in irradiated double-sided 3D silicon sensors

International Nuclear Information System (INIS)

Betta, G.-F. Dalla; Mendicino, R.; Povoli, M.; Sultan, D.M.S.; Ayllon, N.; Hoeferkamp, M.; McDuff, H.; Seidel, S.; Boscardin, M.; Zorzi, N.; Mattiazzo, S.

2016-01-01

We report on an experimental study aimed at gaining deeper insight into the leakage current and breakdown voltage of irradiated double-sided 3D silicon sensors from FBK, so as to improve both the design and the fabrication technology for use at future hadron colliders such as the High Luminosity LHC. Several 3D diode samples of different technologies and layout are considered, as well as several irradiations with different particle types. While the leakage current follows the expected linear trend with radiation fluence, the breakdown voltage is found to depend on both the bulk damage and the surface damage, and its values can vary significantly with sensor geometry and process details.

Superconductivity in heavily boron-doped silicon carbide

Directory of Open Access Journals (Sweden)

Markus Kriener, Takahiro Muranaka, Junya Kato, Zhi-An Ren, Jun Akimitsu and Yoshiteru Maeno

2008-01-01

Full Text Available The discoveries of superconductivity in heavily boron-doped diamond in 2004 and silicon in 2006 have renewed the interest in the superconducting state of semiconductors. Charge-carrier doping of wide-gap semiconductors leads to a metallic phase from which upon further doping superconductivity can emerge. Recently, we discovered superconductivity in a closely related system: heavily boron-doped silicon carbide. The sample used for that study consisted of cubic and hexagonal SiC phase fractions and hence this led to the question which of them participated in the superconductivity. Here we studied a hexagonal SiC sample, free from cubic SiC phase by means of x-ray diffraction, resistivity, and ac susceptibility.

Proton-irradiation technology for high-frequency high-current silicon welding diode manufacturing

Science.gov (United States)

Lagov, P. B.; Drenin, A. S.; Zinoviev, M. A.

2017-05-01

Different proton irradiation regimes were tested to provide more than 20 kHz-frequency, soft reverse recovery “snap-less” behavior, low forward voltage drop and leakage current for 50 mm diameter 7 kA/400 V welding diode Al/Si/Mo structure. Silicon diode with such parameters is very suitable for high frequency resistance welding machines of new generation for robotic welding.

High resolution laser beam induced current images under trichromatic laser radiation: approximation to the solar irradiation.

Science.gov (United States)

Navas, F J; Alcántara, R; Fernández-Lorenzo, C; Martín-Calleja, J

2010-03-01

A laser beam induced current (LBIC) map of a photoactive surface is a very useful tool when it is necessary to study the spatial variability of properties such as photoconverter efficiency or factors connected with the recombination of carriers. Obtaining high spatial resolution LBIC maps involves irradiating the photoactive surface with a photonic beam with Gaussian power distribution and with a low dispersion coefficient. Laser emission fulfils these characteristics, but against it is the fact that it is highly monochromatic and therefore has a spectral distribution different to solar emissions. This work presents an instrumental system and procedure to obtain high spatial resolution LBIC maps in conditions approximating solar irradiation. The methodology developed consists of a trichromatic irradiation system based on three sources of laser excitation with emission in the red, green, and blue zones of the electromagnetic spectrum. The relative irradiation powers are determined by either solar spectrum distribution or Planck's emission formula which provides information approximate to the behavior of the system if it were under solar irradiation. In turn, an algorithm and a procedure have been developed to be able to form images based on the scans performed by the three lasers, providing information about the photoconverter efficiency of photovoltaic devices under the irradiation conditions used. This system has been checked with three photosensitive devices based on three different technologies: a commercial silicon photodiode, a commercial photoresistor, and a dye-sensitized solar cell. These devices make it possible to check how the superficial quantum efficiency has areas dependent upon the excitation wavelength while it has been possible to measure global incident photon-to-current efficiency values approximating those that would be obtained under irradiation conditions with sunlight.

Radiation-disorder and aperiodicity in irradiated ceramics

International Nuclear Information System (INIS)

Hobbs, L.W.

1992-01-01

This final technical report documents the accomplishments of the program of research entitled ''Radiation Disorder and Aperiodicity in Irradiated Ceramics'' for the period June 22, 1989--June 21, 1992. This research forms the latest part on an on-going program, begun at MIT in 1983 under DOE support, which has had as its objectives investigation of the responses in radiation environments of ceramics heavily-irradiated with electrons, neutrons and ions, with potential applications to fusion energy technology and high-level nuclear waste storage. Materials investigated have included SiO 2 , MgAl 2 O 4 , Al 23 O 27 N 5 , SiC, BeO, LiAlO 2 , Li 2 ZrO 3 , CaTiO 3 KTaO 3 and Ca(Zr, Pu)Ti 2 O 7 . The program initially proposed for 1989 had as its major objectives two main thrusts: (1) research on defect aggregation in irradiated non-oxide ceramics, and (2) research on irradiation-induced amorphization of network silicas and phosphates

Current situation of food irradiation practice in U.S.A

International Nuclear Information System (INIS)

Furuta, Masakazu

1996-01-01

It is essential that private food companies adopt the process and retail stores sell irradiated food products in order to popularize food irradiation among consumers. FOOD TECHnology Inc. (former Vindicator Inc.), which is founded in Florida 1992 for the purpose of decontamination of fruit flies infected in Oranges using 60 Co gamma-irradiation, and Carrot Top, which has been selling irradiated foods since 1992, are well known to be actively involved in PA activity of irradiated foods. Carrot Top is now strongly interested in selling tropical fruits from Hawaii, which has been prohibited to ship from Hawaii to the mainland without decontamination treatment by US government because of fruit fly infestation. They got a temporal permit for the shipment of those fruits with irradiation at Chicago. FOOD TECHnology Inc. irradiates chicken, tomatoes, strawberries and mushrooms. Foods for hospitalized patients and astronauts are also irradiated at FOOD TECHnology Inc.. All food supply for the 'Space Shuttle' program has been provided. Recently they began to irradiate frozen shrimps and salmons. Carrot Top says that irradiated food items gain popularity among their customers although they changed the information transfer method from news letter to news paper advertisement as well as minimizing the description in the store. They noted that the goods sold well whether or not they are irradiated if they are fresh, good-looking and reasonable in price. FOOD TECHnology also commented that food industries has become more friendly towards food irradiation and they petitioned FDA for clearance of beef irradiation to decontaminate E. coli 0157:H7, but the private companies still hesitated to pick up this process therefore we need more efforts of PR. (J.P.N.)

Formation Mechanism of Micropores on the Surface of Pure Aluminum Induced by High-Current Pulsed Electron Beam Irradiation

International Nuclear Information System (INIS)

Zou Yang; Cai Jie; Wan Ming-Zhen; Lv Peng; Guan Qing-Feng

2011-01-01

The mechanism of micropores formed on the surface of polycrystalline pure aluminum under high-current pulsed electron beam (HCPEB) irradiation is explained. It is discovered that dispersed micropores with sizes of 0.1–1 μm on the irradiated surface of pure aluminum can be successfully fabricated after HCPEB irradiation. The dominant formation mechanism of the surface micropores should be attributed to the formation of supersaturation vacancies within the near surface during the HCPEB irradiation and the migration of vacancies along grain boundaries and/or dislocations towards the irradiated surface. It is expected that the HCPEB technique will become a new method for the rapid synthesis of surface porous materials. (condensed matter: structure, mechanical and thermal properties)

Short-channel drain current model for asymmetric heavily/lightly ...

Indian Academy of Sciences (India)

The paper presents a drain current model for double gate metal oxide semiconductor field effect transistors (DG MOSFETs) based on a new velocity saturation model that accounts for short-channel velocity saturation effect independently in the front and the back gate controlled channels under asymmetric front and back ...

High critical currents in heavily doped (Gd,Y)Ba{sub 2}Cu{sub 3}O{sub x} superconductor tapes

Energy Technology Data Exchange (ETDEWEB)

Selvamanickam, V., E-mail: selva@uh.edu; Gharahcheshmeh, M. Heydari; Xu, A.; Galstyan, E.; Delgado, L. [Department of Mechanical Engineering and Texas Center for Superconductivity, University of Houston, 4800 Calhoun Rd., Houston, Texas 77204-4006 (United States); Cantoni, C. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37381 (United States)

2015-01-19

REBa{sub 2}Cu{sub 3}O{sub x} ((REBCO), RE = rare earth) superconductor tapes with moderate levels of dopants have been optimized for high critical current density in low magnetic fields at 77 K, but they do not exhibit exemplary performance in conditions of interest for practical applications, i.e., temperatures less than 50 K and fields of 2–30 T. Heavy doping of REBCO tapes has been avoided by researchers thus far due to deterioration in properties. Here, we report achievement of critical current densities (J{sub c}) above 20 MA/cm{sup 2} at 30 K, 3 T in heavily doped (25 mol. % Zr-added) (Gd,Y)Ba{sub 2}Cu{sub 3}O{sub x} superconductor tapes, which is more than three times higher than the J{sub c} typically obtained in moderately doped tapes. Pinning force levels above 1000 GN/m{sup 3} have also been attained at 20 K. A composition map of lift factor in J{sub c} (ratio of J{sub c} at 30 K, 3 T to the J{sub c} at 77 K, 0 T) has been developed which reveals the optimum film composition to obtain lift factors above six, which is thrice the typical value. A highly c-axis aligned BaZrO{sub 3} (BZO) nanocolumn defect density of nearly 7 × 10{sup 11 }cm{sup −2} as well as 2–3 nm sized particles rich in Cu and Zr have been found in the high J{sub c} films.

Mechanical properties of low temperature proton irradiated single crystal copper

International Nuclear Information System (INIS)

Schildcrout, M.

1975-01-01

Single crystal copper samples, of varying degrees of cold work, were irradiated near either liquid helium or liquid nitrogen temperature by 10.1-MeV protons. The internal friction and dynamic Young's modulus were observed as a function of either temperature or integrated proton flux. The primary effect of irradiation was to produce dislocation pinning. The initial pinning rate was found to be very sensitive to cold work. During irradiation it was found that heavily cold worked samples (25 percent compression) exhibited, almost exclusively, exponential pinning given by Y = e/sup --lambda phi/. This is attributed to the immobilization, rather than shortening, of loop lengths and is characterized by the pinning constant lambda. Exponential pinning was also found, to a smaller degree, in less heavily cold worked samples. Cold work appears to reduce the ''effective volume'' within which the defect clusters produced by irradiation, can immobilize dislocation segments. The bulk effect was observed after dislocation pinning was completed. Expressed in terms of the fractional change in Young's modulus per unit concentration of irradiation induced defects, it was measured at liquid helium temperature to be --18.5 +- 3. An anelastic process occurring near 10 0 K for low kHz frequencies and due to stress-induced ordering of point defects produced by irradiation has also been studied. The peak height per unit fluence was found to decrease with increasing cold work. The peak was not observed in samples compressed 25 percent. For the most carefully handled sample the activation energy was (1.28 +- 0.05) x 10 -2 eV, the attempt frequency was 10/sup 11.6 +- .8/ s -1 , the shape factor was 0.20, and the half width of the peak was 11 percent larger than the theoretical value calculated from the Debye equation for a single relaxation process

Proton-irradiation technology for high-frequency high-current silicon welding diode manufacturing

International Nuclear Information System (INIS)

Lagov, P B; Drenin, A S; Zinoviev, M A

2017-01-01

Different proton irradiation regimes were tested to provide more than 20 kHz-frequency, soft reverse recovery “snap-less” behavior, low forward voltage drop and leakage current for 50 mm diameter 7 kA/400 V welding diode Al/Si/Mo structure. Silicon diode with such parameters is very suitable for high frequency resistance welding machines of new generation for robotic welding. (paper)

Thermally stimulated current of electron beam irradiation cross-linked polyethylene, (3)

International Nuclear Information System (INIS)

Aihara, Mitsugu; Aida, Fumio; Shiono, Takeo

1984-01-01

In the past, electron-beam irradiation was for the most part applied to rather thin insulation electric cables. Considering application to thick insulation, high voltage power cables (6.6 kV or more), the authors experimented on the charge accumulation and crystallizing properties of polyethylene due to irradiation, using three differently crystallizing samples, high and low density polyethylenes (HDPE and LDPE) and straight chain low density polyethylene (LLDPE), and have obtained some findings. Those are summarized as follows. (1) The crystallizing properties (crystallinity, the size of spherulite, etc.) of polyethylene varied according to the cooling condition, and affected the thermally stimulated current (TSC). (2) In HDPE and LDPE, the behaviour of crystallization differed. In HDPE, fine crystals decreased, and spherulites significantly grew in slow cooling, but in LDPE, the generation of fine crystals and the growth of spherulites simultaneously progressed. (3) The TSC peak area for HDPE was scarcely affected by slow cooling, but that for LDPE greatly increased. (4) The TSC of irradiated polyethylene showed peaks corresponding to the melting temperatures of fine crystals and spherulites when collecting voltage Vc was lowered. (5) The above facts suggest that fine crystals and spherulites took part as charge trap sites, but the aspect of participation was different in HDPE and LDPE. (6) LLDPE has the properties of both HDPE and LDPE in view of the crystallinity, charge accumulation was small, and it was hard to be affected by cooling condition. Accordingly, it seemed to be an interesting material as the PE for irradiation. A differential scanning calorimeter and laser small angle scattering method were used for the analysis of the measured results of TSC. (Wakatsuki, Y.)

Whole bone marrow irradiation for the treatment of multiple myeloma

International Nuclear Information System (INIS)

Coleman, M.; Saletan, S.; Wolf, D.; Nisce, L.; Wasser, J.; McIntyre, O.R.; Tulloh, M.

1982-01-01

Nine patients with multiple myeloma were treated with whole bone marrow irradiation. Six had heavily pretreated disease refractory to chemotherapy. Three had stable disease lightly pretreated by chemotherapy. A modification of the ''three and two'' total nodal radiation technique was employed. Although varying and often severe treatment related cytopenia occurred, infectious complications, clinical bleeding, and nonhematalogic complications were minimal. Five of nine patients showed a decrease in monoclonal protein components, and one showed an increase during treatment. These preliminary results indicate that a reduction of tumor cell burden may occur in patients following whole bone marrow irradiation and that the technique is feasible. Whole bone marrow irradiation combined with chemotherapy represents a new conceptual therapeutic approach for multiple myeloma

Effects of gamma irradiation on voltage-dependant NA+ and K+ currents in N1E-115 cells

International Nuclear Information System (INIS)

Diserbo, M.; Barbier, M.; Quignard, J.F.

1998-01-01

Effects of 15 Gy gamma irradiation on voltage-dependent Na + and K + currents in differentiated N1E-115 cells are studied by using whole cell recording. Only, we observed an activation of Na + currents at a lower threshold. (authors)

Multiple relaxation processes in high-energy ion irradiated kapton-H polyimide: Thermally stimulated depolarization current study

International Nuclear Information System (INIS)

Garg, Maneesha; Quamara, J.K.

2006-01-01

High-energy ion irradiation effects on the thermally stimulated depolarization current (Tdc) behaviour of kapton-H samples (12.5 μm) irradiated with 50 MeV Li ion (fluence 5 x 10 4 , 10 5 and 5 x 10 5 ions/cm 2 ) have been investigated. The TSDC spectra of the irradiated samples reveal that the β-peak (appearing around 80-110 deg. C) associated with dipolar relaxation has been significantly affected owing to the demerization of carbonyl groups due to irradiation. The TSDC spectra also reveal a new relaxation process (termed as γ-relaxation) around 30 deg. C, due to increased water absorptivity in irradiated samples. The peak around 200 deg. C (α-peak) associated with space charge relaxation process also shows a behavioural change with ion irradiation. The peak not only shifts towards the higher temperature with increasing fluence but also show an increase in its activation energy (0.33-0.99 eV) with increasing polarizing field. The creation of new deep energy trap centers due to the formation of conjugated bonds after irradiation is responsible for this modification. The Cole-Cole distribution curves show the formation of new sub-polar group with different characteristic relaxation time

Current status of irradiation facilities in JRR-3 and JRR-4

International Nuclear Information System (INIS)

Hori, Naohiko; Wada, Shigeru; Sasajima, Fumio; Kusunoki, Tsuyoshi

2006-01-01

The Department of Research Reactor has operated two research reactors, JRR-3 and JRR-4. These reactors were constructed in the Tokai Research Establishment. Many researchers and engineers use these joint-use facilities. JRR-3 is a light water moderated and cooled, pool type research reactor using low-enriched silicide fuel. JRR-3's maximum thermal power is 20MW. JRR-3 has nine vertical irradiation holes for RI production, nuclear fuels and materials irradiation at reactor core area. JRR-3 has many kinds of irradiation holes in a heavy water tank around the reactor core. These are two hydraulic rabbit irradiation facilities, two pneumatic rabbit irradiation facilities, one activation analysis irradiation facilities, one uniform irradiation facility, one rotating irradiation facility and one capsule irradiation facility. JRR-3 has nine horizontal experimental holes, that are used by many kinds of neutron beam experimental facilities using these holes. JRR-4 is a light water moderated and cooled, swimming pool type research reactor using low-enriched silicide fuel. JRR-4's maximum thermal power is 3.5MW. JRR-4 has five vertical irradiation tubes at reactor core area, three capsule irradiation facilities, one hydraulic rabbit irradiation facility, and one pneumatic rabbit irradiation facility. JRR-4 has a neutron beam hole, and it has used neutron beam experiments, irradiations for activation analysis and medical neutron irradiations. (author)

Comparison on mechanical properties of heavily phosphorus- and arsenic-doped Czochralski silicon wafers

Science.gov (United States)

Yuan, Kang; Sun, Yuxin; Lu, Yunhao; Liang, Xingbo; Tian, Daxi; Ma, Xiangyang; Yang, Deren

2018-04-01

Heavily phosphorus (P)- and arsenic (As)-doped Czochralski silicon (CZ-Si) wafers generally act as the substrates for the epitaxial silicon wafers used to fabricate power and communication devices. The mechanical properties of such two kinds of n-type heavily doped CZ silicon wafers are vital to ensure the quality of epitaxial silicon wafers and the manufacturing yields of devices. In this work, the mechanical properties including the hardness, Young's modulus, indentation fracture toughness and the resistance to dislocation motion have been comparatively investigated for heavily P- and As-doped CZ-Si wafers. It is found that heavily P-doped CZ-Si possesses somewhat higher hardness, lower Young's modulus, larger indentation fracture toughness and stronger resistance to dislocation motion than heavily As-doped CZ-Si. The mechanisms underlying this finding have been tentatively elucidated by considering the differences in the doping effects of P and As in silicon.

The current legal situation relating to food irradiation as assessed by the Land Government

International Nuclear Information System (INIS)

Frede, W.

1994-01-01

Discussed is the current legal situation of food irradiation procedures as assessed by the Government of Northrhine-Westfalia. The topics highest on the agenda are the unrestrained exchange of merchandise within the Internal Market and the problems arising from deviating legal stipulations in the individual EU member states. (vhe) [de

Stem cell migration after irradiation

International Nuclear Information System (INIS)

Nothdurft, W.; Fliedner, T.M.

1979-01-01

The survival rate of irradiated rodents could be significantly improved by shielding only the small parts of hemopoietic tissues during the course of irradiation. The populations of circulating stem cells in adult organisms are considered to be of some importance for the homeostasis between the many sites of blood cell formation and for the necessary flexibility of hemopoietic response in the face of fluctuating demands. Pluripotent stem cells are migrating through peripheral blood as has been shown for several mammalian species. Under steady state conditions, the exchange of stem cells between the different sites of blood cell formation appears to be restricted. Their presence in blood and the fact that they are in balance with the extravascular stem cell pool may well be of significance for the surveilance of the integrity of local stem cell populations. Any decrease of stem cell population in blood below a critical size results in the rapid immigration of circulating stem cells in order to restore local stem cell pool size. Blood stem cells are involved in the regeneration after whole-body irradiation if the stem cell population in bone marrows is reduced to less than 10% of the normal state. In the animals subjected to partial-body irradiation, the circulating stem cells appear to be the only source for the repopulation of the heavily irradiated, aplastic sites of hemopoietic organs. (Yamashita, S.)

Irradiation behavior of graphite shielding materials for FBR

International Nuclear Information System (INIS)

Maruyama, Tadashi; Kaito, Takeji; Onose, Shoji; Shibahara, Itaru

1994-01-01

Thirteen kinds of isotropic graphites with different density and maximum grain size were irradiated in the experimental fast reactor 'JOYO' to fluences from 2.11 to 2.86x10 26 n/m 2 (E>0.1 MeV) at temperatures from 549 to 597degC. Postirradiation examination was carried out on dimensional change, elastic modulus, and the thermal conductivity. The result of measurement of dimensional change indicated that the graphites irradiated at lower fluences showed shrinkage upon neutron irradiation followed by increase with increasing neutron fluences, irrespective of differences in material parameters. The Young's modulus and Poisson's ratio increased to two to three times of unirradiated values. A large scatter found in Poisson's ratio of unirradiated materials became very small and a linear dependency on density was obtained after irradiation. The thermal conductivity decreased to one-fifth to one-tenth of unirradiated values, but the change in specific heat was negligibly small. The results of postirradiation examination indicated that the changes in physical properties of high density, isotropic graphites were mainly dominated by the irradiation condition rather than their material parameters. Namely, the effects of irradiation induced defects on physical properties of heavily neutron-irradiated graphites are much larger than that of defects associated with as-fabricated specimens. (author)

Magnetic studies of current conduction and flux pinning in high-Tc cuprates: Virgin, irradiated, and oxygen deficient materials

International Nuclear Information System (INIS)

Thompson, J.R.; Civale, L.; Marwick, A.D.; Holtzberg, F.

1992-09-01

To increase the current density and pinning of magnetic flux in high temperature superconductors, defects with point-like and line-like geometries were created in controlled numbers using ion irradiation methods. Single crystals of Y 1 Ba 2 Cu 3 O 7 and Bi 2 Sr 2 Ca 1 Cu 2 0 8 superconductors were studied using dc magnetic methods. These studies showed greatly increased irreversibility in the vortex state magnetization and enhanced intragrain current density J c following irradiation. Linear defects, created by irradiation with energetic heavy ions, are particularly effective in pinning vortices at higher temperatures and magnetic fields. Further investigations of ''flux creep'' (the time dependence of magnetization) are well described by recent vortex glass and collective pinning theories. Complementary investigations have delineated the role of oxygen deficiency δ on pinning in aligned Y 1 Ba 2 Cu 3 O 7-δ materials

a Study of Oxygen Precipitation in Heavily Doped Silicon.

Science.gov (United States)

Graupner, Robert Kurt

Gettering of impurities with oxygen precipitates is widely used during the fabrication of semiconductors to improve the performance and yield of the devices. Since the effectiveness of the gettering process is largely dependent on the initial interstitial oxygen concentration, accurate measurements of this parameter are of considerable importance. Measurements of interstitial oxygen following thermal cycles are required for development of semiconductor fabrication processes and for research into the mechanisms of oxygen precipitate nucleation and growth. Efforts by industrial associations have led to the development of standard procedures for the measurement of interstitial oxygen in wafers. However practical oxygen measurements often do not satisfy the requirements of such standard procedures. An additional difficulty arises when the silicon wafer has a low resitivity (high dopant concentration). In such cases the infrared light used for the measurement is severely attenuated by the electrons of holes introduced by the dopant. Since such wafers are the substrates used for the production of widely used epitaxial wafers, this measurement problem is economically important. Alternative methods such as Secondary Ion Mass Spectroscopy or Gas Fusion Analysis have been developed to measure oxygen in these cases. However, neither of these methods is capable of distinguishing interstitial oxygen from precipitated oxygen as required for precipitation studies. In addition to the commercial interest in heavily doped silicon substrates, they are also of interest for research into the role of point defects in nucleation and precipitation processes. Despite considerable research effort, there is still disagreement concerning the type of point defect and its role in semiconductor processes. Studies of changes in the interstitial oxygen concentration of heavily doped and lightly doped silicon wafers could help clarify the role of point defects in oxygen nucleation and precipitation

Effect of 520 MeV Kr{sup 20+} ion irradiation on the critical current density of Bi-2212 single crystals

Energy Technology Data Exchange (ETDEWEB)

Terai, Takayuki; Ito, Yasuyuki [Tokyo Univ. (Japan). Faculty of Engineering; Kishio, Kouji

1996-10-01

Change in magnetic properties of Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+y} (Bi-2212) single crystals due to Kr{sup 20+} ion irradiation is reported, focused on critical current density and irreversibility magnetic field. The Bi-2212 single crystal specimens (3x3x0.3 mm{sup 3}) were prepared by the floating zone method. Each specimen was irradiated with 520 MeV Kr{sup 20+} ions of 10{sup 10}-10{sup 11} cm{sup -2} in the fluence. Magnetic hysteresis was measured at 4.2K-60K with a vibrating sample magnetometer before and after irradiation. Very large enhancement was observed in critical current density and irreversibility magnetic field above 20K. (author)

Growth and characterization of heavily doped silicon crystals

Energy Technology Data Exchange (ETDEWEB)

Scala, R.; Porrini, M. [MEMC Electronic Materials SpA, via Nazionale 59, 39012 Merano (Italy); Borionetti, G. [MEMC Electronic Materials SpA, viale Gherzi 31, Novara (Italy)

2011-08-15

Silicon crystals grown with the Czochralski method are still the most common material used for the production of electronic devices. In recent years, a growing need of large diameter crystals with increasingly higher doping levels is observed, especially to support the expanding market of discrete devices and its trend towards lower and lower resistivity levels for the silicon substrate. The growth of such heavily doped, large-diameter crystals poses several new challenges to the crystal grower, and the presence of a high dopant concentration in the crystal affects significantly its main properties, requiring also the development of dedicated characterization techniques. This paper illustrates the recent advances in the growth and characterization of silicon crystals heavily doped with antimony, arsenic, phosphorus and boron. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Evaluation of the effect of probe design parameters on ECT signal and development of eddy current probe for irradiated fuel rods

International Nuclear Information System (INIS)

Kwank, S. W.; Han, Y. K.; Woo, S. K.; Kim, T. W.; Park, J. Y.; Kim, B. J.; Park, J. Y.

1999-01-01

Eddy current test(ECT) is used to inspect not only the failed fuel rods but also peripheral rods during repairing of the failed fuel rods, to detect internal defects in irradiated fuel rods which could not be detected by ultrasonic test and visual test, and to obtain the data for determining the root cause of fuel rod failure. This study evaluates the effect of properties of test article, irradiated fuel rods, on the impedance diagram in order to reduce the difficulty of ECT signal analysis. The optimum eddy current probe design conditions for inspecting the irradiated fuel rods, is estimate by using experimental equations and the probe is manufactured based on the estimated conditions. The performance of developed eddy current probe and the optimum conditions is proved through characteristic comparison experiment with the probe purchased from the foreign vendor

Modelling property changes in graphite irradiated at changing irradiation temperature

CSIR Research Space (South Africa)

Kok, S

2011-01-01

Full Text Available A new method is proposed to predict the irradiation induced property changes in nuclear; graphite, including the effect of a change in irradiation temperature. The currently used method; to account for changes in irradiation temperature, the scaled...

Current status of food irradiation overseas. Data update from 2013

International Nuclear Information System (INIS)

Todoriki, Setsuko

2015-01-01

As the movement of international standards and specifications, the treatment standards related to food irradiation have been summarized on the basis of the ISPM 28 Annex PT-19 of International Plant Protection Convention. As the movement in the United States, there are the following tables: (1) food and radiation dose approved by FDA, (2) lowest radiation dose for the pests of each quarantine target stipulated by the USDA/APHIS as the plant quarantine authorities of the United States Department of Agriculture, (3) items and production sites of vegetables/fruits about which irradiation treatment in import phytosanitary has been approved by USDA, and (4) import volume of irradiated fruits into the United States. The following statistics have also been summarized: (1) materials and irradiation dose permitted FSANZ, which is the food safety regulatory authorities of Australia and New Zealand, and (2) irradiation-treated amount of each food in the EU territory in 2013, and treated amount in each country. In Asia, the amount and facilities of irradiation treatment are described for ten countries including China, Thailand, India, etc. As the contents of the Coordinated Research Programs (CRPs) of International Atomic Energy Agency (IAEA), the following are introduced: (1) three items including 'Development of generic irradiation doses for quarantine treatments,' and (2) three items of the contents of 'The Regional Cooperative Agreement for Research, Development and Training Related to Nuclear Science and Technology for Asia and the Pacific: RCA).' (A.O.)

Optical properties of electron-irradiated gallium phosphide

International Nuclear Information System (INIS)

Brailovskii, E.Yu.; Grigoryan, N.E.; Eritsyan, G.N.

1980-01-01

Results of optical absorption and photoconductivity measurements in the 0.1 to 2.4 eV range of GaP crystals irradiated with 7.5 and 50 MeV electrons are presented. The absorption of irradiated crystals near the edge can be represented by two exponential regions. In the free carrier absorption region one can observe as a result of irradiation a decrease of the power index p in the dependence α proportional to lambdap. Photoconductivity with long-time relaxation takes place in the spectral interval where the additional absorption is observed. The quenching of residual conductivity can be observed at hν=1.0eV. Variations in absorption and photoconductivity are attributed to the 'tails' of density states near the zone edges arising at introduction of both point defects and disordered regions. At hν=2.1eV one can observe a resonance band which is attributed to intra-centre transitions on point defects. A recovery of the optical properties of GaP at annealing is studied. In heavily irradiated GaP crystals point defects can form gatherings which display themselves as disordered regions. (author)

Irradiation-induced mutation experiments with eiploid and tetraploid tomato plants

International Nuclear Information System (INIS)

Boda, J.

1979-01-01

Tomato mutation experiments are described. The tomatoes used in the experiment were the diploid Reziszta and its autotetraploid variety. The experimental plants were exposed to an irradiation of 5000 rsd for 1-2 days, and after transplantation into the gamma field, to chronic irradiation during the whole growing season. The chronic treatment heavily reduced fertility in the generations of tetraploid tomato plants. Recurrent treatment of tetraploid led to further deterioration in fertility. Several berries were formed with few seeds or with no seeds at all. After three irradiations, the chlorophyll mutation frequency increased in the diploid and tetraploid tomato plants. For diploids, treatment applied at the seedling stage gave a lower chlorophyll mutation frequency. With tetraploids the same treatment induced similar chlorophyll mutation frequency. As regards to phenotypic variability of quantitative characteristics in diploid and tetraploid tomatoes, the single and repeated chronic irradiation induced no increase in the variability of properties like flowering time, weight, height etc. (author)

Models of Solar Irradiance Variations: Current Status Natalie A ...

Indian Academy of Sciences (India)

Abstract. Regular monitoring of solar irradiance has been carried out since 1978 to show that solar total and spectral irradiance varies at different time scales. Whereas variations on time scales of minutes to hours are due to solar oscillations and granulation, variations on longer time scales are driven by the evolution of the ...

Short circuit current changes in electron irradiated GaAlAs/GaAs solar cells

Science.gov (United States)

Walker, G. H.; Conway, E. J.

1978-01-01

Heteroface p-GaAlAs/p-GaAs/n-GaAs solar cells with junction depths of 0.8, 1.5, and 4 microns were irradiated with 1 MeV electrons. The short-circuit current for the 4 micron junction depth cells is significantly reduced by the electron irradiation. Reduction of the junction depth to 1.5 microns improves the electron radiation resistance of the cells while further reduction of the junction depth to 0.8 microns improves the stability of the cells even more. Primary degradation is in the blue region of the spectrum. Considerable recovery of lost response is obtained by annealing the cells at 200 C. Computer modeling shows that the degradation is caused primarily by a reduction in the minority carrier diffusion length in the p-GaAs.

IRRAD: The New 24GeV/c Proton Irradiation Facility at CERN

CERN Document Server

Gkotse, Blerina; Moll, Michael; Ravotti, Federico

2016-01-01

The proton and mixed-field irradiation facilities at the CERN PS East Area (known as IRRAD1 and IRRAD2), have been heavily exploited for irradiation of particle detectors, electronic components and materials since 1992. With the increasing demand of irradiation experiments, and in view of the High-Luminosity upgrade of the CERN Large Hadron Collider (HL-LHC), these facilities suffered of a number of unpleasant restrictions such as the space availability, the maximum achievable particle flux and several access constraints. In the framework of the AIDA project, an upgrade of these facilities was carried out during the Long Shutdown 1 (LS1) of the CERN accelerator complex. The new combined East Area IRRADiation facility (EA-IRRAD) started the commissioning in October 2014. While the new proton facility (IRRAD) continue to be mainly devoted to the radiation hardness studies for the High Energy Physics community, the new mixed-field facility (CHARM) mainly hosts irradiation experiments for the validation of electr...

Investigation of the double exponential in the current-voltage characteristics of silicon solar cells. [proton irradiation effects on ATS 1 cells

Science.gov (United States)

Wolf, M.; Noel, G. T.; Stirn, R. J.

1977-01-01

Difficulties in relating observed current-voltage characteristics of individual silicon solar cells to their physical and material parameters were underscored by the unexpected large changes in the current-voltage characteristics telemetered back from solar cells on the ATS-1 spacecraft during their first year in synchronous orbit. Depletion region recombination was studied in cells exhibiting a clear double-exponential dark characteristic by subjecting the cells to proton irradiation. A significant change in the saturation current, an effect included in the Sah, Noyce, Shockley formulation of diode current resulting from recombination in the depletion region, was caused by the introduction of shallow levels in the depletion region by the proton irradiation. This saturation current is not attributable only to diffusion current from outside the depletion region and only its temperature dependence can clarify its origin. The current associated with the introduction of deep-lying levels did not change significantly in these experiments.

Food irradiation: An update

International Nuclear Information System (INIS)

Morrison, Rosanna M.

1984-01-01

Recent regulatory and commercial activity regarding food irradiation is highlighted. The effects of irradiation, used to kill insects and microorganisms which cause food spoilage, are discussed. Special attention is given to the current regulatory status of food irradiation in the USA; proposed FDA regulation regarding the use of irradiation; pending irradiation legislation in the US Congress; and industrial applications of irradiation

Structural changes in the regenerating rat thymus after irradiation

Energy Technology Data Exchange (ETDEWEB)

Fukumoto, Tetsuo; Wang, Yu-Hsueh; Hashimoto, Noriko; Tokuda, Nobuko; Sawada, Tomoo [Yamaguchi Univ., Ube (Japan). School of Medicine

1999-11-01

The structural changes of the rat thymus after irradiation were examined. Thymocytes regenerate rapidly after irradiation and the mechanism responsible for this rapid regeneration was examined analyzing vascular and immunohistochemical changes in the thymus. Following results were obtained: Vascular fine mesh works in the cortex were destroyed on day 3 after 6 Gy irradiation, while on day 5 these changes appeared to be restored to almost normal. Massive macrophage accumulations were observed in the cortex on day 3-5 after irradiation. This may be due to clean up the damaged thymocytes, although other possibility, as production of cytokines which may contribute to the rapid proliferation must be intensively examined. Immunohistochemical staining with anti MHC class II molecule showed relatively strong staining in the medulla compared to the cortex in the normal thymus, while this finding was reversed and cortex stained heavily compared to the medulla on day 5-7 after irradiation suggesting the importance of the cortical MHC class II positive thymic epithelial cells in regeneration of thymocytes. Anti FTS antibody stained relatively strongly in the irradiated and recovering thymus compared to the normal. These results may partly explain the abrupt proliferation of thymocytes after irradiation and further studies on cytokine message changes and thymic epithelial characterization responsible to produce the cytokines for the effective thymocyte proliteration are on the way of analysis. (author)

Heavily nitrogen doped, graphene supercapacitor from silk cocoon

International Nuclear Information System (INIS)

Sahu, Vikrant; Grover, Sonia; Tulachan, Brindan; Sharma, Meenakshi; Srivastava, Gaurav; Roy, Manas; Saxena, Manav; Sethy, Niroj; Bhargava, Kalpana; Philip, Deepu; Kim, Hansung; Singh, Gurmeet; Singh, Sushil Kumar; Das, Mainak; Sharma, Raj Kishore

2015-01-01

Doping of graphene with nitrogen is of much interest, since it improves the overall conductivity and supercapacitive properties. Besides conductivity, nitrogen doping also enhances the pseudo-capacitance due to fast and reversible surface redox processes. In this work, we have developed a cheap and easy process for synthesizing heavily nitrogen doped graphene (15% nitrogen) from non-mulberry silk cocoon membrane (Tassar, Antheraea mylitta) by pyrolyzing the cocoon at 400 °C in argon atmosphere. Further we have investigated the performance of this heavily ‘nitrogen doped graphene’ (NDG) in a supercapacitor device. Our results suggest that NDG obtained from cocoon has improved supercapacitor performance. The improved performance is due to the high electronegativity of nitrogen that forms dipoles on the graphene surface. These dipoles consequently enhance the tendency of graphene to attract charged species to its surface. This is a green and clean synthesis approach for developing electronic materials for energy applications

Food irradiation: current problems and future potential

International Nuclear Information System (INIS)

Kilcast, D.

1995-01-01

Food irradiation is one of a set of processing technologies that can be used to increase the microbiological safety and shelf-life of a wide range of foods. Ionizing radiation is used to generate highly active chemical species within the food, which react with DNA. Under normal usage conditions, the food receives a pasteurizing treatment that gives a valuable reduction in common food-spoilage organisms and food pathogens. This review describes how the process is used in practice, including the benefits and limitations. The nature of changes to food components are outlined, together with the development of practical detection methods that utilize these changes. The legislative position of food irradiation is outlined, with the specific example of the introduction of the technology within the UK. The reasons for the slow uptake in the use of the technology are discussed, and the problem of consumer acceptance is addressed. (author)

Current mapping of low-energy (120 eV) helium and hydrogen irradiated tungsten by conductive atomic force microscopy

Energy Technology Data Exchange (ETDEWEB)

Fan, Hongyu [School of Physics and Materials Engineering, Dalian Nationalities University, Dalian (China); Endo, Takashi [Nano-micro Materials Analysis Laboratory, Hokkaido University, Sapporo (Japan); Bi, Zhenghua; Yan, Weibin [School of Physics and Materials Engineering, Dalian Nationalities University, Dalian (China); Ohnuki, Somei [Nano-micro Materials Analysis Laboratory, Hokkaido University, Sapporo (Japan); Yang, Qi; Ni, Weiyuan [School of Physics and Materials Engineering, Dalian Nationalities University, Dalian (China); Liu, Dongping, E-mail: dongping.liu@dlnu.edu.cn [School of Physics and Materials Engineering, Dalian Nationalities University, Dalian (China)

2017-04-01

Both conductive atomic force microscopy (CAFM) and transmission electron microscopy have been used to characterize the defects or He bubbles in low-energy (120 eV) H and He irradiated tungsten (W). By a comparative study, we find that the current mapping from CAFM is very sensitive in the detection of nanometer-sized defects in low-energy H and He irradiated W. Our calculation confirms that the resistance change in H and He irradiated W is strongly affected by the distance between atomic force microscopy tip and defects/He bubbles. CAFM can accurately detect defects/He bubbles in the W surface layer, however, it is infeasible to measure them in the deep layer (>20 nm), especially due to the existence of defects in the surface layer.

Pulsed eddy current inspection system for nondestructive examination of irradiated fuel rods

International Nuclear Information System (INIS)

Yancey, M.E.

1979-01-01

An inspection system has been developed for nondestructive examination of irradiated fuel rods utilizing pulsed eddy current techniques. The system employs an encircling type pulsed eddy current transducer capable of sensing small defects located on both the inner and outer diameter fuel rod surfaces during a single scan. Pulsed eddy current point probes are used to provide fuel rod wall thikness data and an indication of radial defect location. Two linear variable differential transformers are used to provide information on fuel rod diameter variation. A microprocessor based control system is used to automatically scan fuel rods up to 4.06 meters in length at predetermined radial locations. Defects as small as 0.005 cm deep by 0.254 cm long by 0.005 cm wide have been detected on outside diameter surfaces of a 1.43 cm outside diameter fuel rod cladding with a 0.094 cm wall thickness and 0.010 cm deep by 0.254 cm long by 0.005 cm wide on the inside diameter surface

Analytical solutions for thermal transient profile in solid target irradiated with low energy and high beam current protons

International Nuclear Information System (INIS)

Oliveira, Henrique B. de; Brazao, Nei G.; Sciani, Valdir

2009-01-01

There were obtained analytical solutions for thermal transient in solid targets, used in short half-life radioisotopes production, when irradiated with low energy and high beam current protons, in the cyclotron accelerator Cyclone 30 of the Institute for Energy and Nuclear Research (IPEN/CNEN-SP). The beam spatial profile was considered constant and the time depended heat distribution equation was resolved for a continuous particles flow entering the target. The problem was divided into two stages: a general solution was proposed which is the sum of two functions, the first one related to the thermal equilibrium situation and the second one related to a time dependent function that was determinate by the setting of the contour conditions and the initial conditions imposed by the real problem. By that one got an analytic function for a complete description of the heat transport phenomenon inside the targets. There were used both, numerical and symbolic computation methods, to obtain temperature maps and thermal gradients and the results showed an excellent agreement when compared with purely numerical models. The results were compared with obtained data from Gallium-67 and Thallium-201 irradiation routines conducted by the IPEN Cyclotrons accelerators center, showing excellent agreement. The objective of this paper is to develop solid targets irradiation systems (metals and oxides) so that one can operate with high levels of current beam, minimizing the irradiation time and maximizing the final returns. (author)

TSD current investigations in pristine and 100 MeV Ni-ion irradiated PET/0.3 PHB polymer liquid crystal

International Nuclear Information System (INIS)

Quamara, J.K.; Singh, Nafa; Prabhavathi, T.; Sridharbabu, Y.

2002-01-01

The dielectric relaxations investigations have been carried out in pristine as well as 100 MeV 58 Ni ion irradiated (PELLETRON facility, Nuclear Science Center, New Delhi) PET/0.3 PHB PLC samples. Thermally stimulated depolarization current technique (TSDC) has been employed for this purpose. The plc samples were polarized at 180 deg C under the influence of various polarizing fields following the usual method. Three current maxima are observed around 35deg, 120deg and 155degC which are ascribed as β', β and α transitions. These transitions are mainly due to the fast reacting dipoles of PHB regions, dipolar character due to carbonyl groups in PET rich phase and to the cold crystallization of PET. The results confirm the biphasic nature of this plc. The high energy irradiation influences both β and α transitions. Increase in fluence shifts the β peak as well as α peak towards higher temperature. This confirms that high energy irradiation has not only affected the carbonyl groups but has created new phases. (author)

Detection methods for irradiated foods: current status. Proceedings

International Nuclear Information System (INIS)

McMurray, C.H.; Gray, R.; Stewart, E.M.; Pearce, J.; Queen's Univ., Belfast, Northern Ireland

1996-01-01

This book contains a scientific record of an international meeting on analytical detection methods for irradiation treatment of food. Apart from encouraging the basic development of detection tests, the meeting also aimed to assess the various test methods critically to determine their suitability for general use by public health laboratories and others concerned with trade in irradiated food. Two sets of criteria have been developed to assess test methods, technical criteria for a qualitative or quantitative test and practical criteria if a method is to be widely applied by food labelling authorities. Agreement has already been achieved for the use of electron spin resonance, thermoluminescence, hydrocarbons, 2-Alkylcyclobutanones, microbiological, viscometry and impedance tests. (UK)

Feasibility of Helical Tomotherapy for Debulking Irradiation Before Stem Cell Transplantation in Malignant Lymphoma

International Nuclear Information System (INIS)

Chargari, Cyrus; Vernant, Jean-Paul; Tamburini, Jerome; Zefkili, Sofia; Fayolle, Maryse; Campana, Francois; Fourquet, Alain; Kirova, Youlia M.

2011-01-01

Purpose: Preliminary clinical experience has suggested that radiation therapy (RT) may be effectively incorporated into conditioning therapy before transplant for patients with refractory/relapsed malignant lymphoma. We investigated the feasibility of debulking selective lymph node irradiation before autologous and/or allogeneic stem cell transplantation (SCT) using helical tomotherapy (HT). Methods and Materials: Six consecutive patients with refractory malignant lymphoma were referred to our institution for salvage HT before SCT. All patients had been previously heavily treated but had bulky residual tumor despite chemotherapy (CT) intensification. Two patients had received previous radiation therapy. HT delivered 30-40 Gy in the involved fields (IF), using 6 MV photons, 2 Gy per daily fraction. Total duration of treatment was 28 to 35 days. Results: Using HT, doses to critical organs (heart, lungs, esophagu, and parotids) were significantly decreased and highly conformational irradiation could be delivered to all clinical target volumes. HT delivery was technically possible, even in patients with lesions extremely difficult to irradiate in other conditions or in patients with previous radiation therapy. No Grade 2 or higher toxicity occurred. Four months after the end of HT, 5 patients experienced complete clinical, radiologic, and metabolic response and were subsequently referred for SCT. Conclusions: By more effectively sparing critical organs, HT may contribute to improving the tolerance of debulking irradiation before allograft. Quality of life may be preserved, and doses to the heart may be decreased. This is particularly relevant in heavily treated patients who are at risk for subsequent heart disease. These preliminary results require further prospective assessment.

High-dose irradiated food: Current progress, applications, and prospects

Science.gov (United States)

Feliciano, Chitho P.

2018-03-01

Food irradiation as an established and mature technology has gained more attention in the food industry for ensuring food safety and quality. Primarily used for phytosanitary applications, its use has been expanded for developing various food products for varied purposes (e.g. ready-to-eat & ready-to-cook foods, hospital diets, etc.). This paper summarized and analyzed the recent progress and application of high-dose irradiation and discussed its prospects in the field of food product development, its safety and quality.

Impact of doped boron concentration in emitter on high- and low-dose-rate damage in lateral PNP transistors

International Nuclear Information System (INIS)

Zheng Yuzhan; Lu Wu; Ren Diyuan; Wang Yiyuan; Wang Zhikuan; Yang Yonghui

2010-01-01

The characteristics of radiation damage under a high or low dose rate in lateral PNP transistors with a heavily or lightly doped emitter is investigated. Experimental results show that as the total dose increases, the base current of transistors would increase and the current gain decreases. Furthermore, more degradation has been found in lightly-doped PNP transistors, and an abnormal effect is observed in heavily doped transistors. The role of radiation defects, especially the double effects of oxide trapped charge, is discussed in heavily or lightly doped transistors. Finally, through comparison between the high- and low-dose-rate response of the collector current in heavily doped lateral PNP transistors, the abnormal effect can be attributed to the annealing of the oxide trapped charge. The response of the collector current, in heavily doped PNP transistors under high- and low-dose-rate irradiation is described in detail. (semiconductor integrated circuits)

Change of mechanical properties of irradiated silicon iron in dependence of preliminary deformation

International Nuclear Information System (INIS)

Chirkina, L.A.; Okovit, V.S.; Khinkis, B.A.

1979-01-01

Presented are the data on the influence of the 225 MeV electron irradiation on flow limit and specific elongation of silicon iron specimens preliminary deformed by slipping and twinning. The irradiaton was carried out at the temperature up to 350 K with integral dose up to 7x10 18 el/cm 2 . The specimens were tested in the temperature range of 4-450 K. It is found that the ductile brittle transition temperature Tsub(c) and plastic deformation mode of the irradiated material heavily depends on the preliminary deformation mode. The irradiation of specimens deformed by slipping leads to the increase in transition temperature (Tsub(c)) by 80 deg and it reaches 420 K. The preliminary deformation by twinning results in the Tsub(c) increase up to 320 K

Irradiation Facilities at CERN

CERN Document Server

Gkotse, Blerina; Carbonez, Pierre; Danzeca, Salvatore; Fabich, Adrian; Garcia, Alia, Ruben; Glaser, Maurice; Gorine, Georgi; Jaekel, Martin, Richard; Mateu,Suau, Isidre; Pezzullo, Giuseppe; Pozzi, Fabio; Ravotti, Federico; Silari, Marco; Tali, Maris

2017-01-01

CERN provides unique irradiation facilities for applications in many scientific fields. This paper summarizes the facilities currently operating for proton, gamma, mixed-field and electron irradiations, including their main usage, characteristics and information about their operation. The new CERN irradiation facilities database is also presented. This includes not only CERN facilities but also irradiation facilities available worldwide.

The effect of low-temperature neutron irradiation on the critical current of some superconducting materials

International Nuclear Information System (INIS)

Takamura, S.; Okuda, S.

1978-01-01

The critical current densities of pure V and Nb single crystals, single core Nb-50 wt% Ti coated with Cu and Nb 3 Sn were measured after fast neutron irradiation at about 5 K and during subsequent annealings. The peak effect was observed in V and Nb single cyrstals immediately after irradiation. In V, the peak effect disappeared after subsequent annealing above 200 K (in the so-called stage III recovery where vacancies are considered to anneal out in V). In contrast, in Nb the peak effect did not disappear even after annealing at 300 K (above the stage III recovery of Nb). Furthermore, in V the peak effect showed a remarkable recovery at 120 K where about 50% of the resistivity increase recovered. The elementary force of the fluxoid-defect interaction was estimated in V single crystals. (Auth.)

Critical current densities and flux creep rate in Co-doped BaFe2As2 with columnar defects introduced by heavy-Ion irradiation

International Nuclear Information System (INIS)

Nakajima, Y.; Tsuchiya, Y.; Taen, T.; Yagyuda, H.; Tamegai, T.; Okayasu, S.; Sasase, M.; Kitamura, H.; Murakami, T.

2010-01-01

We report the formation of columnar defects in Co-doped BaFe 2 As 2 single crystals with different heavy-ion irradiations. The formation of columnar defects by 200 MeV Au ion irradiation is confirmed by transmission electron microscopy and their density is about 40% of the irradiation dose. Magneto-optical imaging and bulk magnetization measurements reveal that the critical current density J c is enhanced in the 200 MeV Au and 800 MeV Xe ion irradiated samples while J c is unchanged in the 200 MeV Ni ion irradiated sample. We also find that vortex creep rates are strongly suppressed by the columnar defects. We compare the effect of heavy-ion irradiation into Co-doped BaFe 2 As 2 and cuprate superconductors.

The natural aging of austenitic stainless steels irradiated with fast neutrons

Science.gov (United States)

Rofman, O. V.; Maksimkin, O. P.; Tsay, K. V.; Koyanbayev, Ye. T.; Short, M. P.

2018-02-01

Much of today's research in nuclear materials relies heavily on archived, historical specimens, as neutron irradiation facilities become ever more scarce. These materials are subject to many processes of stress- and irradiation-induced microstructural evolution, including those during and after irradiation. The latter of these, referring to specimens "naturally aged" in ambient laboratory conditions, receives far less attention. The long and slow set of rare defect migration and interaction events during natural aging can significantly change material properties over decadal timescales. This paper presents the results of natural aging carried out over 15 years on austenitic stainless steels from a BN-350 fast breeder reactor, each with its own irradiation, stress state, and natural aging history. Natural aging is shown to significantly reduce hardness in these steels by 10-25% and partially alleviate stress-induced hardening over this timescale, showing that materials evolve back towards equilibrium even at such a low temperature. The results in this study have significant implications to any nuclear materials research program which uses historical specimens from previous irradiations, challenging the commonly held assumption that materials "on the shelf" do not evolve.

Magnetic resonance thermometry for monitoring photothermal effects of interstitial laser irradiation

Science.gov (United States)

Goddard, Jessica; Jose, Jessnie; Figueroa, Daniel; Le, Kelvin; Liu, Hong; Nordquist, Robert E.; Hode, Tomas; Chen, Wei R.

2012-03-01

Selective photothermal interaction using dye-assisted non-invasive laser irradiation has limitations when treating deeper tumors or when the overlying skin is heavily pigmented. We developed an interstitial laser irradiation method to induce the desired photothermal effects. An 805-nm near-infrared laser with a cylindrical diffuser was used to treat rat mammary tumors by placing the active tip of the fiber inside the target tumors. Three different power settings (1.0 to 1.5 watts) were applied to treat animal tumors with an irradiation duration of 10 minutes. The temperature distributions of the treated tumors were measured by a 7.1-Tesla magnetic resonance imager using proton resonance frequency (PRF) method. Three-dimensional temperature profiles were reconstructed and assessed using PRF. This is the first time a 7.1-Tesla magnetic resonance imager has been used to monitor interstitial laser irradiation via PRF. This study provides a basic understanding of the photothermal interaction needed to control the thermal damage inside tumor using interstitial laser irradiation. It also shows that PRF can be used effectively in monitoring photothermal interaction. Our long-term goal is to develop a PRF-guided laser therapy for cancer treatment.

Lack of appetite for food irradiation

International Nuclear Information System (INIS)

Tacey, Elisabeth

1989-01-01

The British government has approved food irradiation in Britain on a much wider scale than has taken place previously. The implications for one of the companies currently offering a gamma irradiation service are explored. Irradiation is by a large Cobalt 60 source. Currently the customers are medical, cosmetic and packaging firms. It does not yet have the facilities necessary for large-scale food irradiation, nor does it expect a huge demand for food irradiation as customer resistance is strong. However some dry spices and herbs may be treated next year. (UK)

Backward diodes using heavily Mg-doped GaN growth by ammonia molecular-beam epitaxy

Science.gov (United States)

Okumura, Hironori; Martin, Denis; Malinverni, Marco; Grandjean, Nicolas

2016-02-01

We grew heavily Mg-doped GaN using ammonia molecular-beam epitaxy. The use of low growth temperature (740 °C) allows decreasing the incorporation of donor-like defects (p-type doping compensation. As a result, a net acceptor concentration of 7 × 1019 cm-3 was achieved, and the hole concentration measured by Hall effect was as high as 2 × 1019 cm-3 at room temperature. Using such a high Mg doping level, we fabricated GaN backward diodes without polarization-assisted tunneling. The backward diodes exhibited a tunneling-current density of 225 A/cm2 at a reverse bias of -1 V at room temperature.

Remote Excavation of Heavily Contaminated UXO Sites. The Range Master

National Research Council Canada - National Science Library

Crandall, Alan L

2007-01-01

USA Environmental, Inc., and Timberline Environmental Services, Inc., developed the Range Master, a remote controlled scraper with an integrated power screen, to excavate and sift the top 12 inches of heavily contaminated UXO sites...

Current status and regulation of food irradiation

International Nuclear Information System (INIS)

Sivinski, J.S.

1987-01-01

It is estimated by the Food and Agricultural Organization (FAO) of the United Nations that 25 to 35 percent of world food production is lost through natural causes such a pests, microbes, and insects. In the ASEAN countries alone, postharvest losses of cereals are estimated at 30 percent, fruits and vegetables at 20 to 40 percent, and up to 50 percent for fish. Some products in Africa suffer postharvest losses as high as 50 percent. One of the best responses to the problem of world hunger is preservation of what has already been grown. If postharvest losses worldwide could be minimized, food supply gains could be made without allocation of additional resources. The problems of food production, processing and storage require a continuing search for effective, technically and economically feasible alternative methods of food preservation. Food irradiation is not a panacea for this problem, however. Alone, it cannot change conditions or solve the problems of world hunger, but it can become a factor in the improvement of conditions where improved human nutrition is an immediate need. Food irradiation has progressed steadily over the past 40 years in terms of research, development, and legislative or regulatory activities

Electrochemical Decontamination of Painted and Heavily Corroded Metals

International Nuclear Information System (INIS)

Marczak, S.; Anderson, J.; Dziewinski, J.

1998-01-01

The radioactive metal wastes that are generated from nuclear fuel plants and radiochemical laboratories are mainly contaminated by the surface deposition of radioactive isotopes. There are presently several techniques used in removing surface contamination involving physical and chemical processes. However, there has been very little research done in the area of soiled, heavily oxidized, and painted metals. Researchers at Los Alamos National Laboratory have been developing electrochemical procedures for the decontamination of bare and painted metal objects. These methods have been found to be effective on highly corroded as well as relatively new metals. This study has been successful in decontaminating projectiles and shrapnel excavated during environmental restoration projects after 40+ years of exposure to the elements. Heavily corroded augers used in sampling activities throughout the area were also successfully decontaminated. This process has demonstrated its effectiveness and offers several advantages over the present metal decontamination practices of media blasting and chemical solvents. These advantages include the addition of no toxic or hazardous chemicals, low operating temperature and pressure, and easily scaleable equipment. It is in their future plans to use this process in the decontamination of gloveboxes destined for disposal as TRU waste

Proton irradiation induced defects in Cd and Zn doped InP

International Nuclear Information System (INIS)

Rybicki, G.C.; Williams, W.S.

1993-01-01

Proton irradiation induced defects in Zn and Cd doped InP have been studied by deep level transient spectroscopy, (DLTS). After 2 MeV proton irradiation the defects H4 and H5 were observed in lightly Zn doped InP, while the defects H3 and H5 were observed in more heavily Zn and Cd doped InP. The defect properties were not affected by the substitution of Cd for Zn, but the introduction rate of H5 was lower in Cd doped InP. The annealing rate of defects was also higher in Cd doped InP. The use of Cd doped InP may thus result in an InP solar cell with even greater radiation resistance

Food irradiation

International Nuclear Information System (INIS)

Matsuyama, Akira

1990-01-01

This paper reviews researches, commentaries, and conference and public records of food irradiation, published mainly during the period 1987-1989, focusing on the current conditions of food irradiation that may pose not only scientific or technologic problems but also political issues or consumerism. Approximately 50 kinds of food, although not enough to fill economic benefit, are now permitted for food irradiation in the world. Consumerism is pointed out as the major factor that precludes the feasibility of food irradiation in the world. In the United States, irradiation is feasible only for spices. Food irradiation has already been feasible in France, Hollands, Belgium, and the Soviet Union; has under consideration in the Great Britain, and has been rejected in the West Germany. Although the feasibility of food irradiation is projected to increase gradually in the future, commercial success or failure depends on the final selection of consumers. In this respect, the role of education and public information are stressed. Meat radicidation and recent progress in the method for detecting irradiated food are referred to. (N.K.) 128 refs

Functional State of Haemopoietic Stem Cells in the Irradiated Mouse

Energy Technology Data Exchange (ETDEWEB)

Silini, G.; Pozzi, Laura V. [Laboratorio di Radiobiologica Animale, Centro Studi Nucleari, Casaccia, Rome (Italy)

1968-08-15

The repopulation kinetics of bone marrow in irradiated (C3H x C57BL) F{sub 1} hybrid mice were followed at different time intervals after a single whole-body dose of 150 rad X -rays. The changes in the number of total nucleated cells and of colony-forming cells were estimated and expressed as number of cells per femur shaft of fixed length. For the evaluation of the progenitor cell compartment an exogenous test of transplantation into heavily irradiated hosts followed by spleen colony counts was employed. In an attempt to distinguish between cycling and dormant cells in the progenitor pool, vinblastine was also administered under various schedules of treatment with respect to time and dosage to follow the changes induced by this drug in the irradiated recovering marrow. The depopulation of total bone-m arrow cells caused by vinblastine proceeded at a comparable rate in both the irradiated and the normal mouse. On the other hand, depopulation of the colony-formers is faster in animals irradiated 1 -2 days previously as compared with normal animals or mice irradiated 1 week or 2 weeks earlier. The data were interpreted to show that in the marrow of a newly-irradiated animal more cells are in a fast cycle than in a normal or a recovering animal. Data are finally presented and discussed concerning the use of vinblastine for studies of stem cell kinetics in haemopoietic tissues. (author)

A New High-intensity Proton Irradiation Facility at the CERN PS East Area

CERN Document Server

Gkotse, B; Lima, P; Matli, E; Moll, M; Ravotti, F

2014-01-01

and IRRAD2), were heavily and successfully used for irradiation of particle detectors, electronic components and materials since 1992. These facilities operated with particle bursts - protons with momentum of 24GeV/c - delivered from the PS accelerator in “spills” of about 400ms (slow extraction). With the increasing demand of irradiation experiments, these facilities suffered from a number of restrictions such as the space availability, the maximum achievable particle flux and several access constraints. In the framework of the AIDA project, an upgrade of these facilities has been realized during the CERN long shutdown (LS1). While the new proton facility (IRRAD) will continue to be mainly devoted to the radiation hardness studies for the High Energy Physics (HEP) experimental community, the new mixed-field facility (CHARM) will mainly host irradiation experiments for the validation of electronic systems used in a...

Influence of coil current modulation on polycrystalline diamond film deposition by irradiation of Ar/CH4/H2 inductively coupled thermal plasmas

Science.gov (United States)

Betsuin, Toshiki; Tanaka, Yasunori; Arai, T.; Uesugi, Y.; Ishijima, T.

2018-03-01

This paper describes the application of an Ar/CH4/H2 inductively coupled thermal plasma with and without coil current modulation to synthesise diamond films. Induction thermal plasma with coil current modulation is referred to as modulated induction thermal plasma (M-ITP), while that without modulation is referred to as non-modulated ITP (NM-ITP). First, spectroscopic observations of NM-ITP and M-ITP with different modulation waveforms were made to estimate the composition in flux from the thermal plasma by measuring the time evolution in the spectral intensity from the species. Secondly, we studied polycrystalline diamond film deposition tests on a Si substrate, and we studied monocrystalline diamond film growth tests using the irradiation of NM-ITP and M-ITP. From these tests, diamond nucleation effects by M-ITP were found. Finally, following the irradiation results, we attempted to use a time-series irradiation of M-ITP and NM-ITP for polycrystalline diamond film deposition on a Si substrate. The results indicated that numerous larger diamond particles were deposited with a high population density on the Si substrate by time-series irradiation.

Dimensional measurements and eddy currents control of the sheath integrity for a set of irradiated candu fuel elements

International Nuclear Information System (INIS)

Gheorghe, G.; Man, I.

2015-01-01

During irradiation in the nuclear reactor, fuel elements undergo dimensional and structural changes, and changes of sheath surface condition as well, which can lead to damages and even loss of integrity. This paper presents the results of dimensional measurements and of examination technique with eddy currents for three fuel elements of an irradiated CANDU fuel bundle. One of the fuel elements (FE), which is studied in detail, presented a crack about 40 mm long. The purpose of these nondestructive examination techniques is to determine those parameters that characterize the behavior and performance of nuclear fuel operation. This paper contains images of defects and interpretations of the causes of their occurrence. (authors)

Perspective on food irradiation

International Nuclear Information System (INIS)

Newsome, R.L.

1987-01-01

A brief review summarizes current scientific information on the safety and efficacy of irradiation processing of foods. Attention is focused on: specifics of the irradiation process and its effectiveness in food preservation; the historical development of food irradiation technology in the US; the response of the Institute of Food Technologists to proposed FDA guidelines for food irradiation; the potential uses of irradiation in the US food industry; and the findings of the absence of toxins and of unaltered nutrient density (except possibly for fats) in irradiated foods. The misconceptions of consumers concerning perceived hazards associated with food irradiation, as related to consumer acceptance, also are addressed

Optimal conditions for high current proton irradiations at the university of Wisconsin's ion beam laboratory

International Nuclear Information System (INIS)

Wetteland, C. J.; Field, K. G.; Gerczak, T. J.; Eiden, T. J.; Maier, B. R.; Albakri, O.; Sridharan, K.; Allen, T. R.

2013-01-01

The National Electrostatics Corporation's (NEC) Toroidal Volume Ion Source (TORVIS) source is known for exceptionally high proton currents with minimal service downtime as compared to traditional sputter sources. It has been possible to obtain over 150μA of proton current from the source, with over 70μA on the target stage. However, beam fluxes above ∼1×10 17 /m2-s may have many undesirable effects, especially for insulators. This may include high temperature gradients at the surface, sputtering, surface discharge, cracking or even disintegration of the sample. A series of experiments were conducted to examine the role of high current fluxes in a suite of ceramics and insulating materials. Results will show the optimal proton irradiation conditions and target mounting strategies needed to minimize unwanted macro-scale damage, while developing a procedure for conducting preliminary radiation experiments.

Luminescence from {gamma}-irradiated humic acid

Energy Technology Data Exchange (ETDEWEB)

Goraczko, Wieslaw [Faculty of Chemical Technology, Radio- and Photochemistry Department, Poznan University of Technology, ul. Piotrowo 3, 60-965 Poznan (Poland); Slawinski, Janusz [Institute of Ecotechnology, State Higher Vocational School, ul. Ks. Kard. S.Wyszynskiego 38, 62-200 Gniezno (Poland)

2008-07-15

This study was conducted to investigate the ultraweak delayed radiochemiluminescence (RCL) spectra, kinetics and spectroscopic properties of humic acids (HAs) after {gamma}-radiation exposure (absorbed doses of 1-10 kGy, Co-60) in model systems. The kinetics and spectral distribution of RCL (340-650 nm) were measured using the single photon counting (SPC) method and cut-off filters. The intensity of fluorescence ({lambda}{sub ex}=390, 440, 490 and 540 nm) covering the spectral range 400-580 nm was heavily dependent on the {lambda}{sub ex} and slightly increased with the absorbed dose of {gamma}-radiation. Absorption spectra (the range 240-800 nm) and color coefficients E{sub 2.6/4} and E{sub 4/6} of irradiated solutions indicated that post-radiative degradation/polymerization processes take place in the HA, changing their macromolecule size or properties. Comparison of FTIR spectra and elemental analysis proved an increased O and decreased C atoms in irradiated samples. The data indicate on the radiolysis-induced degradation of native HA into fulvic-like acids with higher hydrophilicity and lower molecular size.

Luminescence from γ-irradiated humic acid

International Nuclear Information System (INIS)

Goraczko, Wieslaw; Slawinski, Janusz

2008-01-01

This study was conducted to investigate the ultraweak delayed radiochemiluminescence (RCL) spectra, kinetics and spectroscopic properties of humic acids (HAs) after γ-radiation exposure (absorbed doses of 1-10 kGy, Co-60) in model systems. The kinetics and spectral distribution of RCL (340-650 nm) were measured using the single photon counting (SPC) method and cut-off filters. The intensity of fluorescence (λ ex =390, 440, 490 and 540 nm) covering the spectral range 400-580 nm was heavily dependent on the λ ex and slightly increased with the absorbed dose of γ-radiation. Absorption spectra (the range 240-800 nm) and color coefficients E 2.6/4 and E 4/6 of irradiated solutions indicated that post-radiative degradation/polymerization processes take place in the HA, changing their macromolecule size or properties. Comparison of FTIR spectra and elemental analysis proved an increased O and decreased C atoms in irradiated samples. The data indicate on the radiolysis-induced degradation of native HA into fulvic-like acids with higher hydrophilicity and lower molecular size

Proton and gamma -Rays Irradiation-Induced Dark Current Random Telegraph Signal in a 0.18-mu{{m}} CMOS Image Sensor

Science.gov (United States)

Martin, E.; Nuns, T.; Virmontois, C.; David, J.-P.; Gilard, O.

2013-08-01

The dark current random telegraph signal (RTS) behavior has been studied in a five-transistor-per-pixel (5T) pinned photodiode 0.18-μm COTS active pixel sensor (APS). Several devices, irradiated using protons and gamma rays, have been studied in order to assess the ionizing and displacement damage effects. The influence of the proton energy, fluence, ionizing dose and applied bias during irradiation on the number of RTS pixels, the number of discrete levels, maximum transition amplitude, and mean switching time constants is investigated.

Effects of synchronous irradiance monitoring and correction of current-voltage curves on the outdoor performance measurements of photovoltaic modules

Science.gov (United States)

Hishikawa, Yoshihiro; Doi, Takuya; Higa, Michiya; Ohshima, Hironori; Takenouchi, Takakazu; Yamagoe, Kengo

2017-08-01

Precise outdoor measurement of the current-voltage (I-V) curves of photovoltaic (PV) modules is desired for many applications such as low-cost onsite performance measurement, monitoring, and diagnosis. Conventional outdoor measurement technologies have a problem in that their precision is low when the solar irradiance is unstable, hence, limiting the opportunity of precise measurement only on clear sunny days. The purpose of this study is to investigate an outdoor measurement procedure, that can improve both the measurement opportunity and precision. Fast I-V curve measurements within 0.2 s and synchronous measurement of irradiance using a PV module irradiance sensor very effectively improved the precision. A small standard deviation (σ) of the module’s maximum output power (P max) in the range of 0.7-0.9% is demonstrated, based on the basis of a 6 month experiment, that mainly includes partly sunny days and cloudy days, during which the solar irradiance is unstable. The σ was further improved to 0.3-0.5% by correcting the curves for the small variation of irradiance. This indicates that the procedure of this study enables much more reproducible I-V curve measurements than a conventional usual procedure under various climatic conditions. Factors that affect measurement results are discussed, to further improve the precision.

Structural, Optical, and Dielectric Investigations of the Relaxor PLZT 9,75/65/35 Ceramics Irradiated by High-Current Pulsed Electron Beam

CERN Document Server

Efimov, V V; Kalmikov, A V; Klevtsova, E A; Minashkin, V F; Novikova, N N; Sikolenko, V V; Skripnik, A V; Sternberg, A; Tiutiunnikov, S I; Yakovlev, V A

2002-01-01

First time comprehensive study of high-current pulsed electron irradiation effects on the structural, optical and dielectric properties of relaxor (Pb_{(1-x)}La^{x}(Zr_{0.65}Ti_{0.35})_{1-x/4}O_{3} ceramics with x=9.75% has been provided. The electron beam had the following parameters: energy E_{e}=250 keV, current density J_{e}=1000 A/cm^{2}, pulse duration tau = 300 ns, density 10^{15} electrons/cm^{2} per pulse. Infrared reflectivity spectra in the region of 100-2000 cm^{-1} were obtained in virgin, irradiated by 1500 pulses and annealed up to t=500^{circ}C ceramics. The reconstruction of perovskite ABO_{3} structure in irradiated samples has been studied by complex use of X-ray and neutron scattering and IR spectroscopy techniques revealing the changes in transverse and longitudinal phonon modes, oscillators strength and damping of modes. Radiation effects on temperature behaviour of dielectric permittivity in the region of phase transition were studied. The possible mechanisms of pulsed electron irradiat...

TEM study of damage recovery in SiC by swift Xe ion irradiation

International Nuclear Information System (INIS)

Skuratov, V.A.; O’Connell, J.; Sohatsky, A.S.; Neethling, J.

2014-01-01

The microstructure of 4H–SiC samples subsequently irradiated with low energy He (10 keV), Ti (220 keV) and high energy (167 MeV) Xe ions has been studied using cross-sectional transmission electron microscopy. It was found that xenon ions with fluences above 10 13 cm −2 restore crystallinity in a heavily damaged partially amorphous zone. No, or negligible damage recovery is observed in fully amorphized layers of silicon carbide

Isothermal oxidation behaviour of thermal barrier coatings with CoCrAlY bond coat irradiated by high-current pulsed electron beam

Energy Technology Data Exchange (ETDEWEB)

Cai, Jie [School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013 (China); Guan, Qingfeng, E-mail: guanqf@mail.ujs.edu.cn [School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013 (China); Hou, Xiuli [School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013 (China); Wang, Zhiping; Su, Jingxin; Han, Zhiyong [College of Science, Civil Aviation University of China, Tianjin 300300 (China)

2014-10-30

Highlights: • The original coarse surface was re-melted by pulsed electron beam irradiation. • Very fine grains were homogeneously dispersed on the irradiated coat surface. • A compact Al{sub 2}O{sub 3} scale was formed in irradiated TBCs at the onset of oxidation. • The selective oxidation of Al element avoided the formation of other oxides. • The irradiated coating has a much higher oxidation resistance. - Abstract: Thermal sprayed CoCrAlY bond coat irradiated by high-current pulsed electron beam (HCPEB) and thermal barrier coatings (TBCs) prepared with the irradiated bond coat and the ceramic top coat were investigated. The high temperature oxidation resistance of these specimens was tested at 1050 °C in air. Microstructure observations revealed that the original coarse surface of the as-sprayed bond coat was significantly changed as the interconnected bulged nodules with a compact appearance after HCPEB irradiation. Abundant Y-rich alumina particulates and very fine grains were dispersed on the irradiated surface. After high temperature oxidation test, the thermally grown oxide (TGO) in the initial TBCs grew rapidly and was comprised of two distinct layers: a large percentage of mixed oxides in the outer layer and a relatively small portion of Al{sub 2}O{sub 3} in the inner layer. Severe local internal oxidation and extensive cracks in the TGO layer were discovered as well. Comparatively, the irradiated TBCs exhibited thinner TGO layer, slower TGO growth rate, and homogeneous TGO composition (primarily consisting of Al{sub 2}O{sub 3}). The results indicate that TBCs with the irradiated bond coat have a much higher oxidation resistance.

Planning of irradiation

Energy Technology Data Exchange (ETDEWEB)

Caha, A; Krystof, V [Vyzkumny Ustav Klinicke a Experimentalni Onkologie, Brno (Czechoslovakia)

1979-07-01

The principles are discussed of the planning of irradiation, ie., the use of the various methods of location of a pathological focus and the possibility of semiautomatic transmission of the obtained data on a two-dimensional or spatial model. An efficient equipment is proposed for large irradiation centres which should cooperate with smaller irradiation departments for which also a range of apparatus is proposed. Irradiation planning currently applied at the Research Institute of Clinical and Experimental Oncology in Brno is described. In conclusion, some of the construction principles of semi-automatic operation of radiotherapy departments are discussed.

Preliminary investigation on the extension of shelf-life of boiled Chub mackerel by irradiation

Energy Technology Data Exchange (ETDEWEB)

Loaharanu, P; Prombubesara, C; Songprasertchai, S

1971-12-31

The influence of irradiation on the extension of shelf-life of boiled Chub mackerel stored at room temperature (25-30{sup 0}C) was investigated. It was found that boiled Chub mackerel irradiated at 0.1, 0.2, or 0.3 Mrad could be kept with good organoleptic properties at room temperature for 5, 8, and 11 days respectively; while the unirradiated sample could be kept for only 2 days. Boiled Chub mackerel used in this study was found to be heavily contaminated with microorganisms. Irradiation at doses mentioned caused reduction of more than 99% of bacteria. Bacillus and Acinetobacter were found to predominate in the irradiated boiled mackerel. The predominant flora in unirradiated boiled mackerel included Micrococcus, Staphylococcus, Bacillus, Acinetobacter, and Proteus. E. coli was always detected in unirradiated samples and was occasionally detected only in samples irradiated at 0.1 Mrad. Trimethylamine nitrogen (TMA-N) content, total volatile basic nitrogen (TVB-N) content, and total bacterial count (TBC) were used as indices of decomposition of both irradiated and unirradiated samples. TMA-N and TBC were found to be good indices of quality of only unirradiated boiled Chub mackerel, whereas TVB-N was found to be a good index of quality of both irradiated and unirradiated samples.

Studies on the immune response to fixed antigens. Preferential induction of helper function with heavily trinitrophenylated sheep erythrocytes, and glutaraldehyde-treated sheep erythrocytes

International Nuclear Information System (INIS)

Kahan, M.; Berman-Goldman, R.; Saltoun, R.; Naor, D.

1976-01-01

Mice primed with heavily trinitrophenylated sheep red cells (TNP 128 SRC) or glutaraldehyde-treated sheep red cells (G-SRC) developed an early helper function mediated by thymus-derived cells. Such mice were able to produce high secondary responses to both hapten and carrier after challenge 2 days after priming, with lightly trinitrophenylated SRC (TNP 0 . 14 SRC). However, the primary response of the TNP 128 SRC or G-SRC-primed mice were very low to undetectable, and their secondary responses were also low when the challenge antigen was administered 4 days after priming or later. Inhibitory humoral factor(s) which were induced in the primed animals appeared responsible for the decreased capacity of primed mice to mount a secondary response when challenged later than 2 days after priming. Transfer of spleen cells from TNP 128 SRC-primed mice to sublethally irradiated recipients circumvents their exposure to inhibitory humoral factor(s) present in intact animals allowing them to react with challenge antigen. Enriched populations of T cells, but not B cells, were able to transfer this early immunologic memory to irradiated recipients. The theoretical and practical implications of these results are discussed

Irradiation emerges as processing alternative

International Nuclear Information System (INIS)

Hatfield, D.

1985-01-01

Anticipating that food irradiation may soon become an important addition to the many food processing techniques currently available, this article discusses many aspects of this process. Primarily, the benefits of irradiation for all foods include insect and bacterial control, increasing the potential to reduce incidences of food-borne illnesses, in addition to delaying the deterioration of fruits and vegetables. Currently approved uses of food irradiation in the U.S. and other countries, a summary of the proposed rule for wider application, and the labeling issue encompassed in the proposal are addressed. Additionally, the areas of great consumer concern--safety and public health implications, are talked about with the conclusion that food irradiation has been declared safe

Measuring the critical current in superconducting samples made of NT-50 under pulse irradiation by high-energy particles

International Nuclear Information System (INIS)

Vasilev, P.G.; Vladimirova, N.M.; Volkov, V.I.; Goncharov, I.N.; Zajtsev, L.N.; Zel'dich, B.D.; Ivanov, V.I.; Kleshchenko, E.D.; Khvostov, V.B.

1981-01-01

The results of tests of superconducting samples of an uninsulated wire of the 0.5 mm diameter, containing 1045 superconducting filaments of the 10 μm diameter made of NT-50 superconductor in a copper matrix, are given. The upper part of the sample (''closed'') is placed between two glass-cloth-base laminate plates of the 50 mm length, and the lower part (''open'') of the 45 mm length is immerged into liquid helium. The sample is located perpendicular to the magnetic field of a superconducting solenoid and it is irradiated by charged particle beams at the energy of several GeV. The measurement results of permissible energy release in the sample depending on subcriticality (I/Isub(c) where I is an operating current through the sample, and Isub(c) is a critical current for lack of the beam) and the particle flux density, as well as of the maximum permissible fluence depending on subcriticality. In case of the ''closed'' sample irradiated by short pulses (approximately 1 ms) for I/Isub(c) [ru

Geometric component of charge pumping current in nMOSFETs due to low-temperature irradiation

Science.gov (United States)

Witczak, S. C.; King, E. E.; Saks, N. S.; Lacoe, R. C.; Shaneyfelt, M. R.; Hash, G. L.; Hjalmarson, H. P.; Mayer, D. C.

2002-12-01

The geometric component of charge pumping current was examined in n-channel metal-oxide-silicon field effect transistors (MOSFETs) following low-temperature irradiation. In addition to the usual dependencies on channel length and gate bias transition time, the geometric component was found to increase with radiation-induced oxide-trapped charge density and decreasing temperature. A postirradiation injection of electrons into the gate oxide reduces the geometric component along with the density of oxide-trapped charge, which clearly demonstrates that the two are correlated. A fit of the injection data to a first-order model for trapping kinetics indicates that the electron trapping occurs predominantly at a single type of Coulomb-attractive trap site. The geometric component results primarily from the bulk recombination of channel electrons that fail to transport to the source or drain during the transition from inversion to accumulation. The radiation response of these transistors suggests that Coulomb scattering by oxide-trapped charge increases the bulk recombination at low temperatures by impeding electron transport. These results imply that the geometric component must be properly accounted for when charge pumping irradiated n-channel MOSFETs at low temperatures.

Current-induced nonuniform enhancement of sheet resistance in A r+ -irradiated SrTi O3

Science.gov (United States)

Roy, Debangsu; Frenkel, Yiftach; Davidovitch, Sagi; Persky, Eylon; Haham, Noam; Gabay, Marc; Kalisky, Beena; Klein, Lior

2017-06-01

The sheet resistance Rs of A r+ irradiated SrTi O3 in patterns with a length scale of several microns increases significantly below ˜40 K in connection with driving currents exceeding a certain threshold. The initial lower Rs is recovered upon warming with accelerated recovery around 70 and 160 K. Scanning superconducting quantum interference device microscopy shows local irreversible changes in the spatial distribution of the current with a length scale of several microns. We attribute the observed nonuniform enhancement of Rs to the attraction of the charged single-oxygen and dioxygen vacancies by the crystallographic domain boundaries in SrTi O3 . The boundaries, which are nearly ferroelectric below 40 K, are polarized by the local electrical field associated with the driven current and the clustered vacancies which suppress conductivity in their vicinity and yield a noticeable enhancement in the device resistance when the current path width is on the order of the boundary extension. The temperatures of accelerated conductivity recovery are associated with the energy barriers for the diffusion of the two types of vacancies.

Irradiation damage in superconductors

International Nuclear Information System (INIS)

Quere, Y.

1989-01-01

Most superconductors are quite sensitive to irradiation defects. Critical temperatures may be depressed, critical currents may be increased, by irradiation, but other behaviours may be encountered. In compounds, the sublattice in which defects are created is of significant importance. 24 refs

Schedule and status of irradiation experiments

International Nuclear Information System (INIS)

Rowcliffe, A.F.; Grossbeck, M.L.; Robertson, J.P.

1998-01-01

The current status of reactor irradiation experiments is presented in tables summarizing the experimental objectives, conditions, and schedule. Currently, the program has four irradiation experiments in reactor, and five experiments in the design or construction stages. Postirradiation examination and testing is in progress on ten experiments

TEM study of damage recovery in SiC by swift Xe ion irradiation

Energy Technology Data Exchange (ETDEWEB)

Skuratov, V.A., E-mail: skuratov@jinr.ru [Joint Institute for Nuclear Research, Dubna (Russian Federation); O’Connell, J. [Centre for HRTEM, Nelson Mandela Metropolitan University, Port Elizabeth (South Africa); Sohatsky, A.S. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Neethling, J. [Centre for HRTEM, Nelson Mandela Metropolitan University, Port Elizabeth (South Africa)

2014-05-01

The microstructure of 4H–SiC samples subsequently irradiated with low energy He (10 keV), Ti (220 keV) and high energy (167 MeV) Xe ions has been studied using cross-sectional transmission electron microscopy. It was found that xenon ions with fluences above 10{sup 13} cm{sup −2} restore crystallinity in a heavily damaged partially amorphous zone. No, or negligible damage recovery is observed in fully amorphized layers of silicon carbide.

Stromal cell migration precedes hemopoietic repopulation of the bone marrow after irradiation

International Nuclear Information System (INIS)

Werts, E.D.; Gibson, D.P.; Knapp, S.A.; DeGowin, R.L.

1980-01-01

Circulation of hemopoietic stem cells into an irradiated site has been thoroughly documented, but migration of stromal cells to repair radiation damage has not. We determined the radiosensitivity of mouse bone marrow stroma and evaluated stromal and hemopoietic repopulation in x-irradiated marrow. The D 0 for growth of colonies of marrow stromal cells (MSC) was 215 to 230 rad. Total-body irradiation (TB) obliterated marrow stromal and hemopoietic cells within 3 days. In contrast, 1 day after 1000 rad leg irradiation (LI), MSC rose to 80% of normal, but fell to 34% by 3 days and recovered to 72% by 30 days. However, femoral nucleated cells diminished to 20% by 3 days and recovered to 74% of normal by 30 days. Likewise, differentiated marrow cells and hemopoietic stem cells were initially depleted. With 1000 rad LI followed 3 h later by 1000 rad to the body while shielding the leg, MSC and femoral nucleated cells recovered to values intermediate between 1000 rad TB and 1000 rad LI. We concluded that: (1) the D 0 for MSC was 215 to 230 rad, (2) stromal repopulation preceded hemopoietic recovery, and (3) immigration of stromal cells from an unirradiated sanctuary facilitated hemopoietic repopulation of a heavily irradiated site

Near-infrared free carrier absorption in heavily doped silicon

International Nuclear Information System (INIS)

Baker-Finch, Simeon C.; McIntosh, Keith R.; Yan, Di; Fong, Kean Chern; Kho, Teng C.

2014-01-01

Free carrier absorption in heavily doped silicon can have a significant impact on devices operating in the infrared. In the near infrared, the free carrier absorption process can compete with band to band absorption processes, thereby reducing the number of available photons to optoelectronic devices such as solar cells. In this work, we fabricate 18 heavily doped regions by phosphorus and boron diffusion into planar polished silicon wafers; the simple sample structure facilitates accurate and precise measurement of the free carrier absorptance. We measure and model reflectance and transmittance dispersion to arrive at a parameterisation for the free carrier absorption coefficient that applies in the wavelength range between 1000 and 1500 nm, and the range of dopant densities between ∼10 18 and 3 × 10 20  cm −3 . Our measurements indicate that previously published parameterisations underestimate the free carrier absorptance in phosphorus diffusions. On the other hand, published parameterisations are generally consistent with our measurements and model for boron diffusions. Our new model is the first to be assigned uncertainty and is well-suited to routine device analysis

Change in physical properties of high density isotropic graphites irradiated in the ?JOYO? fast reactor

Science.gov (United States)

Maruyama, T.; Kaito, T.; Onose, S.; Shibahara, I.

1995-08-01

Thirteen kinds of isotropic graphites with different density and maximum grain size were irradiated in the experimental fast reactor "JOYO" to fluences from 2.11 to 2.86 × 10 26 n/m 2 ( E > 0.1 MeV) at temperatures from 549 to 597°C. Postirradiation examination was carried out on the dimensional changes, elastic modulus, and thermal conductivity of these materials. Dimensional change results indicate that the graphites irradiated at lower fluences showed shrinkage upon neutron irradiation followed by increase with increasing neutron fluences, irrespective of differences in material parameters. The Young's modulus and Poisson's ratio increased by two to three times the unirradiated values. The large scatter found in Poisson's ratio of unirradiated materials became very small and a linear dependence on density was obtained after irradiation. The thermal conductivity decreased to one-fifth to one-tenth of unirradiated values, with a negligible change in specific heat. The results of postirradiation examination indicated that the changes in physical properties of high density, isotropic graphites were mainly dominated by the irradiation condition rather than their material parameters. Namely, the effects of irradiation induced defects on physical properties of heavily neutron-irradiated graphites are much larger than that of defects associated with as-fabricated specimens.

Change in physical properties of high density isotropic graphites irradiated in the ''JOYO'' fast reactor

International Nuclear Information System (INIS)

Maruyama, T.; Kaito, T.; Onose, S.; Shibahara, I.

1995-01-01

Thirteen kinds of isotropic graphites with different density and maximum grain size were irradiated in the experimental fast reactor ''JOYO'' to fluences from 2.11 to 2.86x10 26 n/m 2 (E>0.1 MeV) at temperatures from 549 to 597 C. Postirradiation examination was carried out on the dimensional changes, elastic modulus, and thermal conductivity of these materials. Dimensional change results indicate that the graphites irradiated at lower fluences showed shrinkage upon neutron irradiation followed by increase with increasing neutron fluences, irrespective of differences in material parameters. The Young's modulus and Poisson's ratio increased by two to three times the unirradiated values. The large scatter found in Poisson's ratio of unirradiated materials became very small and a linear dependence on density was obtained after irradiation. The thermal conductivity decreased to one-fifth to one-tenth of unirradiated values, with a negligible change in specific heat. The results of postirradiation examination indicated that the changes in physical properties of high density, isotropic graphites were mainly dominated by the irradiation condition rather than their material parameters. Namely, the effects of irradiation induced defects on physical properties of heavily neutron-irradiated graphites are much larger than that of defects associated with as-fabricated specimens. (orig.)

Cytogenetic study of skin fibroblasts in a case of accidental acute irradiation

International Nuclear Information System (INIS)

Mouthuy, M.; Dutrillaux, B.

1982-01-01

The cytogenetic study of skin fibroblasts from a young boy, heavily irradiated by handling of an iridium-192 source of 25 curies is reported. About half of the cells examined had chromosomal abnormalities. The same clone, with multiple chromosome rearrangement, was observed in cultures from biopsies obtained 25 and 35 months after the accident. Several other clones were detected in vitro. The results obtained from cultures of biopsies from different locations show that no direct relationships were found between the absorbed dose and the frequency of stable chromosomal rearrangements. The comparison of the intrachromosomal rearrangements, mostly inversions, observed in this study with those detected in human pathology, in irradiation experiments in vitro, and in various species of primates indicates that these rearrangements do not occur at random. (orig.)

Addition of sunitinib to cetuximab and irinotecan in patients with heavily pre-treated advanced colorectal cancer

DEFF Research Database (Denmark)

Qvortrup, Camilla; Jensen, Benny Vittrup; Jørgensen, Trine Lembrecht

2010-01-01

Results of continuous sunitinib, in combination with cetuximab and irinotecan every other week (SIC) for compassionate use in heavily pre-treated patients with mCRC are presented.......Results of continuous sunitinib, in combination with cetuximab and irinotecan every other week (SIC) for compassionate use in heavily pre-treated patients with mCRC are presented....

Regolith irradiation stratigraphy at the Apollo 16 and 17 landing sites

Science.gov (United States)

Crozaz, G.

1978-01-01

Additional fossil track measurements in the Apollo 17 deep drill stem, as well as detailed track studies in section 3 of the Apollo 16 deep drill core are reported. Although the upper part of the Apollo 17 core seems to have accreted rapidly, no evidence for a rapid accretion of the lower part, as postulated by some authors, is found. Despite the apparent inhomogeneity of section 60003, its track record is unexpectedly homogeneous; all levels are heavily irradiated and emplacement of big slabs of material is not favored.

IFMIF, a fusion relevant neutron source for material irradiation current status

International Nuclear Information System (INIS)

Knaster, J.; Chel, S.; Fischer, U.; Groeschel, F.; Heidinger, R.; Ibarra, A.; Micciche, G.; Möslang, A.; Sugimoto, M.; Wakai, E.

2014-01-01

The d-Li based International Fusion Materials Irradiation Facility (IFMIF) will provide a high neutron intensity neutron source with a suitable neutron spectrum to fulfil the requirements for testing and qualifying fusion materials under fusion reactor relevant irradiation conditions. The IFMIF project, presently in its Engineering Validation and Engineering Design Activities (EVEDA) phase under the Broader Approach (BA) Agreement between Japan Government and EURATOM, aims at the construction and testing of the most challenging facility sub-systems, such as the first accelerator stage, the Li target and loop, and irradiation test modules, as well as the design of the entire facility, thus to be ready for the IFMIF construction with a clear understanding of schedule and cost at the termination of the BA mid-2017. The paper reviews the IFMIF facility and its principles, and reports on the status of the EVEDA activities and achievements

Perspective on food irradiation

International Nuclear Information System (INIS)

Anon.

1987-01-01

Recent US Food and Drug Administration approval of irradiation treatment for fruit, vegetables and pork has stimulated considerable discussion in the popular press on the safety and efficacy of irradiation processing of food. This perspective is designed to summarize the current scientific information available on this issue

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.

Food irradiation

International Nuclear Information System (INIS)

1991-01-01

Processing of food with low levels of radiation has the potential to contribute to reducing both spoilage of food during storage - a particular problem in developing countries - and the high incidence of food-borne disease currently seen in all countries. Approval has been granted for the treatment of more than 30 products with radiation in over 30 countries but, in general, governments have been slow to authorize the use of this new technique. One reason for this slowness is a lack of understanding of what food irradiation entails. This book aims to increase understanding by providing information on the process of food irradiation in simple, non-technical language. It describes the effects that irradiation has on food, and the plant and equipment that are necessary to carry it out safely. The legislation and control mechanisms required to ensure the safety of food irradiation facilities are also discussed. Education is seen as the key to gaining the confidence of the consumers in the safety of irradiated food, and to promoting understanding of the benefits that irradiation can provide. (orig.) With 4 figs., 1 tab [de

Gemcitabine and capecitabine for heavily pre-treated metastatic colorectal cancer patients

DEFF Research Database (Denmark)

Spindler, Karen-Lise G; Pallisgaard, Niels; Andersen, Rikke F

2014-01-01

AIM: We investigated the efficacy and safety of capecitabine and gemcitabin (GemCap) in heavily pre-treated, therapy-resistant metastatic colorectal cancer (mCRC) patients and the clinical importance of cell-free DNA (cfDNA) measurement. PATIENTS AND METHODS: Patients' inclusion criteria included...

Detection of irradiated food: current progress on the MAFF programme

International Nuclear Information System (INIS)

Blackburn, C.M.; Holley, P.A.; Pryke, D.C.

1994-01-01

In their 1986 report the UK's Advisory Committee on Irradiated Food recognized that a generally applicable test was not available. In view of this the Committee advised that documentary control would have to be maintained throughout the processing chain. The Committee considered that detection tests would be an useful supplement for such a control system, and would do much to reassure consumers. In the following year MAFF initiated an R/D programme covering a wide variety of potential methods. The programme now focuses on developing and validating the most promising of these. Whilst it is unlikely that there will ever be an universal test covering all foods, this programme has now reached a point where tests are becoming available for a wide variety of foods. This paper reviews the progress on a number of last years projects of MAFF (Ministry of Agriculture, Fisheries and Food). In addition to the existing MAFF collaboratively tested non-statutory method for herbs and spices, two other methods have now been published: electron spin resonance spectroscopy for meat, and detection of irradiated poultry using the limulus lyasate test based on the presence on 2-alkyl cyclobutanones in irradiated seafood, poultry and meat. The Ministry also takes an active interest in international programmes including European Community and IAEA/FAO initiatives. (author)

Phosphorus-32 intracavitary irradiation of cystic craniopharyngiomas: current technique and long-term results

International Nuclear Information System (INIS)

Pollock, Bruce E.; Lunsford, L. Dade; Kondziolka, Douglas; Levine, Geoffrey; Flickinger, John C.

1995-01-01

Purpose: The management of patients with craniopharyngiomas is often multifaceted and multidisciplinary. The purpose of this study was to examine the results of phosphorus-32 intracavitary irradiation in the treatment of patients with predominately cystic craniopharyngiomas. Methods and Materials: Thirty patients with cystic craniopharyngiomas underwent phosphorus-32 intracavitary irradiation at our center between 1981 and 1993. The median patient age was 26 years (range, 3-70 years). Thirteen patients had intracavitary irradiation as the primary surgery for their cystic tumors, whereas 17 patients had adjuvant intracavitary irradiation after microsurgical resection, fractionated radiotherapy, or both. Patients in the adjuvant treatment group were more likely to have preoperative anterior pituitary insufficiency (p = 0.008 Fischer exact test) and diabetes insipidus (p = 0.003 Fischer exact test). The median follow-up was 37 months (mean, 46 months, range, 7-116 months). Results: Phosphorus-32 intracavitary irradiation resulted in cyst regression in 28 of 32 treated cysts (88%). Ten patients (33%) have had tumor progression requiring further surgical intervention. Three patients (10%) died: two of tumor progression, and one of unrelated causes. Visual acuity and fields improved or remained stable in 63% of the patients. Fifteen patients had residual anterior pituitary function before intracavitary irradiation and 10 (67%) retained their preoperative endocrine status. New-onset diabetes insipidus occurred in 3 of 17 patients (18%) who had normal posterior pituitary function preoperatively. Fourteen of 20 adult patients (70%) continued to perform at their preoperative functional level; 3 of 5 pediatric patients who were age appropriate at the time of treatment continued to develop normally. No difference was noted between primary and adjuvant treatment patients with respect to cyst control, visual deterioration, or endocrine preservation after phosphorus-32

Defect structures in YBa2Cu3O/sub 7-x/ produced by electron irradiation

International Nuclear Information System (INIS)

Kirk, M.A.; Baker, M.C.; Liu, J.Z.; Lam, D.J.; Weber, H.W.

1987-12-01

Defect structures in YBa 2 Cu 3 O/sub 7-x/ produced by electron irradiation at 300 0 K were investigated by transmission electron microscopy. Threshold energies for the production of visible defects were determined to be 152 keV and 131 keV (+- 7 keV) in directions near the a and b (b > a) axes (both perpendicular to c, the long axis in the orthorhombic structure), respectively. During above threshold irradiations in an electron flux of 3 x 10 18 cm -2 s -1 , extended defects were observed to form and grow to sizes of 10 to 50 nm over 1000 s in material thicknesses 20 to 200 nm. Such low electron threshold energies suggest oxygen atom displacements with recoil energies near 20 eV. The observation of movement of twin boundaries during irradiation just above threshold suggests movement of the basal plane oxygen atoms by direct displacement or defect migration processes. Crystals irradiated above threshold were observed after about 24 hours to have transformed to a structure heavily faulted on planes perpendicular to the c axis. 3 refs., 3 figs

On the influence of extrinsic point defects on irradiation-induced point-defect distributions in silicon

International Nuclear Information System (INIS)

Vanhellemont, J.; Romano-Rodriguez, A.

1994-01-01

A semi-quantitative model describing the influence of interfaces and stress fields on {113}-defect generation in silicon during 1-MeV electron irradiation, is further developed to take into account also the role of extrinsic point defects. It is shown that the observed distribution of {113}-defects in high-flux electron-irradiated silicon and its dependence on irradiation temperature and dopant concentration can be understood by taking into account not only the influence of the surfaces and interfaces as sinks for intrinsic point defects but also the thermal stability of the bulk sinks for intrinsic point defects. In heavily doped silicon the bulk sinks are related with pairing reactions of the dopant atoms with the generated intrinsic point defects or related with enhanced recombination of vacancies and self-interstitials at extrinsic point defects. The obtained theoretical results are correlated with published experimental data on boron-and phosphorus-doped silicon and are illustrated with observations obtained by irradiating cross-section transmission electron microscopy samples of wafer with highly doped surface layers. (orig.)

Issues in food irradiation

International Nuclear Information System (INIS)

Mills, S.

1987-04-01

This discussion paper has two goals: first, to raise public awareness of food irradiation, an emerging technology in which Canada has the potential to build a new industry, mainly oriented to promising overseas markets; and second, to help build consensus among government and private sector decision makers about what has to be done to realize the domestic and export potential. The following pages discuss the potential of food irradiation; indicate how food is irradiated; outline the uses of food irradiation; examine questions of the safety of the equipment and both the safety and nutritional value of irradiated food; look at international commercial developments; assess the current and emerging domestic scene; and finally, draw some conclusions and offer suggestions for action

Current understanding of the effects of enviromental and irradiation variables on RPV embrittlement

International Nuclear Information System (INIS)

Odette, G.R.; Lucas, G.E.; Wirth, B.; Liu, C.L.

1997-01-01

Radiation enhanced diffusion at RPV operating temperatures around 290 degrees C leads to the formation of various ultrafine scale hardening phases, including copper-rich and copper-catalyzed manganese-nickel rich precipitates. In addition, defect cluster or cluster-solute complexes, manifesting a range of thermal stability, develop under irradiation. These features contribute directly to hardening which in turn is related to embrittlement, manifested as shifts in Charpy V-notch transition temperature. Models based on the thermodynamics, kinetics and micromechanics of the embrittlement processes have been developed; these are broadly consistent with experiment and rationalize the highly synergistic effects of most important irradiation (temperature, flux, fluence) and metallurgical (copper, nickel, manganese, phosphorous and heat treatment) variables on both irradiation hardening and recovery during post-irradiation annealing. A number of open questions remain which can be addressed with a hierarchy of new theoretical and experimental tools

Multiscale models of metal behaviour and structural change under the action of high-current electron irradiation

International Nuclear Information System (INIS)

Mayer, A E; Krasnikov, V S; Mayer, P N; Pogorelko, V V

2017-01-01

We present our models of the tensile fracture of metals in the solid and molten states, the melting and the plastic deformation of the solid metals. Also we discuss implementation of these models for simulation of the high current electron beam impact on metals. The models are constructed in the following way: the atomistic simulations are used at the first stage for investigation of dynamics and kinetics of structural defects in material (voids, dislocations, melting cites); equations describing evolution of such defects are constructed, verified, and their parameters are identified by means of comparison with the atomistic simulation result; finally, the defects evolution equations are incorporated into the continuum model of the substance behaviour on the macroscopic scale. The obtained continuum models with accounting of defects subsystems are tested in comparison with the experimental results known from literature. The proposed models not only allow one to describe the metal behaviour under the conditions of intensive electron irradiation, but they also allow one to determine the structural changes in the irradiated material. (paper)

Mid-infrared plasmonic resonances exploiting heavily-doped Ge on Si

Science.gov (United States)

Biagioni, P.; Sakat, E.; Baldassarre, L.; Calandrini, E.; Samarelli, A.; Gallacher, K.; Frigerio, J.; Isella, G.; Paul, D. J.; Ortolani, M.

2015-03-01

We address the behavior of mid-infrared localized plasmon resonances in elongated germanium antennas integrated on silicon substrates. Calculations based on Mie theory and on the experimentally retrieved dielectric constant allow us to study the tunability and the figures of merit of plasmon resonances in heavily-doped germanium and to preliminarily compare them with those of the most established plasmonic material, gold.

Investigation of the stability of polysilicon layers in SOI-structures under irradiation by electrons and hard magnetic field influence

Directory of Open Access Journals (Sweden)

Khoverko Yu. N.

2010-10-01

Full Text Available The properties of recrystallized polysilicon on insulator layers of p-type conductive SOI-structures with different carrier concentration irradiated with high-energy electrons flow about 1017 сm–2 in temperature range 4,2—300 К and high magnetic fields were investigated. It was found that heavily doped laser recrystallized polysilicon on insulator layers show its radiation resistance under irradiation with high-energy electrons and magnetoresistance of such material remains quite low in magnetic field about 14 T does not exceed 1—2%. Such qulity can be applied in designing of microelectronic sensors of mechanical values operable in hard conditions of exploitation.

Space charge sign inversion and electric field reconstruction in 24 GeV/c proton-irradiated MCZ Si p+-n(TD)-n+ detectors processed via thermal donor introduction

International Nuclear Information System (INIS)

Li, Z.; Verbitskaya, E.; Carini, G.; Chen, W.; Eremin, V.; Gul, R.; Haerkoenen, J.; Li, M.

2009-01-01

The aim of this study is the evaluation of radiation effects in detectors based on p-type magnetic czochralski (MCZ) Si that was converted to n-type by thermal donor (TD) introduction. As-processed p + -p-n + detectors were annealed at 430 deg. C resulting in p + -n(TD)-n + structures. The space charge sign and the electric field distribution E(x) in MCz Si p + -n(TD)-n + detectors irradiated by 24 GeV/c protons were analyzed using the data on the current pulse response and the Double Peak (DP) electric field distribution model for heavily irradiated detectors. The approach considers an irradiated detector as a structure with three regions in which the electric field depends on the coordinate, and the induced current pulse response arises from the drift process of free carriers in the detector with variable electric field. Reconstruction of the E(x) profile from the pulse response shapes is performed employing a new method for DP electric field reconstruction. This method includes: (a) a direct extraction of charge loss due to trapping and (b) the fitting of a simulated pulse response to the 'corrected' pulse by adjusting the electric field profiles in the three regions. Reconstruction of E(x) distribution showed that in the diodes irradiated by a proton fluence of (2-4)x10 14 p/cm 2 space charge sign inversion has occurred. This is the evidence that the influence of 24 GeV/c proton radiation on MCz Si p + -n(TD)-n + detectors is similar to that on p + -n-n + detectors based on FZ or diffusion oxygenated n-type Si.

Optimal conditions for high current proton irradiations at the university of Wisconsin's ion beam laboratory

Energy Technology Data Exchange (ETDEWEB)

Wetteland, C. J.; Field, K. G.; Gerczak, T. J. [Materials Science Program, University of Wisconsin, Madison, WI 53706 (United States); Eiden, T. J.; Maier, B. R.; Albakri, O.; Sridharan, K.; Allen, T. R. [Department of Engineering Physics, University of Wisconsin, Madison, WI 53706 (United States)

2013-04-19

The National Electrostatics Corporation's (NEC) Toroidal Volume Ion Source (TORVIS) source is known for exceptionally high proton currents with minimal service downtime as compared to traditional sputter sources. It has been possible to obtain over 150{mu}A of proton current from the source, with over 70{mu}A on the target stage. However, beam fluxes above {approx}1 Multiplication-Sign 10{sup 17}/m2-s may have many undesirable effects, especially for insulators. This may include high temperature gradients at the surface, sputtering, surface discharge, cracking or even disintegration of the sample. A series of experiments were conducted to examine the role of high current fluxes in a suite of ceramics and insulating materials. Results will show the optimal proton irradiation conditions and target mounting strategies needed to minimize unwanted macro-scale damage, while developing a procedure for conducting preliminary radiation experiments.

Quality characteristics of irradiated sesame seeds during storage

International Nuclear Information System (INIS)

Swailam, H.M.

2009-01-01

The effect of using gamma radiation 60 Co on the microbial load , presence of some pathogens, viscosity, oil, fatty acids and amino acids properties of sesame seeds were investigated.The condition storage at ambient temperature (20-28 deg c) was held for one year. Pre-packaged sesame seeds were found to be heavily contaminated with bacteria and fungi. The total bacterial counts were 1,9x10 4 cfu/g,whereas total fungal counts were 3.4x10 4 cfu/g.Samples showed low number of the pathogenic bacterial in control . It was found that the microbiological population greatly reduced with a dose of 10 kGy without affecting their quality attributes , irradiation doses used linearly reduced the viscosity of sesame seeds samples. These irradiation doses caused a decrease in the content of some fatty acids and amino acids and increase in others. At the end of storage period, it is clear that , irradiation dose of 10 kGy greatly reduced the counts of total bacterial count, total fungal count and spore former bacterial to less than 10 cfu/ g. The average counts of faecal coliforms , staphylococcus aureus and enterococcus faecalis did not detected in samples receiving 5 and 10 kGy . the flow index (n) and consistency index (k) were decreased after 12 month of storage in irradiated sesame with 10 kGy. Also, there was a slight increase in acid and peroxide value of oil extracted from sesame seeds treatment with 10 kGy. Meanwhile, there was a decrease in iodine, saponification value and very little decrease in the refractive index. It was found that slightly decreased in total unsaturated fatty acid (0.12%) and total amino acid (0.63%)in sesame irradiated at 10 kGy . so, it can be concluded that 10 kGy of γ-radiation suffice the purpose of this work

Energy stored in irradiated NaCl

International Nuclear Information System (INIS)

Lidiard, A.B.

1979-01-01

Recently reported measurements of the energy stored in heavily irradiated NaCl are reviewed in the light of recent understanding of radiation-damage processes in this material. It is shown that, in the ranges of temperatures and dose rates of these experiments, the F-centres produced by the irradiation are retained principally in the form of colloids: the stored energy is thus a direct measure of the number of F-centres retained in this form. Comparison of these results with the prediction of the recently proposed theory of colloid growth shows that the predictions of the dependence of colloid growth rates upon temperature and dose rate are qualitatively correct. The dependence of stored energy dose, however, appears to require the inclusion of a thermally activated back-reaction and possible modifications to the theory are briefly discussed. However, further experiments in this range of temperatures and dose rates are necessary for more quantitative tests of the theory. This reconsideration of the data does not alter the broad conclusion as to the relative insignificance of stored energy in a natural salt formation used as a radioactive waste repository, although more extensive measurements permitting a more exact test of theory would allow better predictions to be made for such applications. (author)

Optical Gaps in Pristine and Heavily Doped Silicon Nanocrystals: DFT versus Quantum Monte Carlo Benchmarks.

Science.gov (United States)

Derian, R; Tokár, K; Somogyi, B; Gali, Á; Štich, I

2017-12-12

We present a time-dependent density functional theory (TDDFT) study of the optical gaps of light-emitting nanomaterials, namely, pristine and heavily B- and P-codoped silicon crystalline nanoparticles. Twenty DFT exchange-correlation functionals sampled from the best currently available inventory such as hybrids and range-separated hybrids are benchmarked against ultra-accurate quantum Monte Carlo results on small model Si nanocrystals. Overall, the range-separated hybrids are found to perform best. The quality of the DFT gaps is correlated with the deviation from Koopmans' theorem as a possible quality guide. In addition to providing a generic test of the ability of TDDFT to describe optical properties of silicon crystalline nanoparticles, the results also open up a route to benchmark-quality DFT studies of nanoparticle sizes approaching those studied experimentally.

Food irradiation scenario in India

International Nuclear Information System (INIS)

Thomas, Paul

1998-01-01

Over 3 decades of research and developmental effort in India have established the commercial potential for food irradiation to reduce post-harvest losses and to ensure food safety. Current regulations permit irradiation of onions, potatoes and spices for domestic consumption and operation of commercial irradiators for treatment of food. In May 1997 draft rules have been notified permitting irradiation of several additional food items including rice, wheat products, dry fruits, mango, meat and poultry. Consumers and food industry have shown a positive attitude to irradiated foods. A prototype commercial irradiator for spices set up by Board of Radiation and Isotope Technology (BRIT) is scheduled to commence operation in early 1998. A commercial demonstration plant for treatment of onions is expected to be operational in the next 2 years in Lasalgaon, Nashik district. (author)

Food irradiation--US regulatory considerations

International Nuclear Information System (INIS)

Morehouse, Kim M.

2002-01-01

The use of ionizing radiation in food processing has received increased interest as a means of reducing the level of foodborne pathogens. This overview discusses the regulatory issues connected with the use of this technology in the United States. Several recent changes in the FDA's review process are discussed. These include the current policy that utilizes an expedited review process for petitions seeking approval of additives and technologies intended to reduce pathogen levels in food, and the recent USDA rule that eliminates the need for a separate rulemaking process by USDA for irradiation of meat and poultry. Recently promulgated rules and pending petitions before the FDA associated with the use of ionizing radiation for the treatment of foods are also discussed along with the current FDA labeling requirements for irradiated foods and the 1999 advanced notice of proposed rule on labeling. Another issue that is presented is the current status of the approval of packaging materials intended for food contact during irradiation treatment of foods

Test-beam evaluation of heavily irradiated silicon strip modules for ATLAS Phase-II Strip Tracker Upgrade

CERN Document Server

Blue, Andrew; The ATLAS collaboration

2018-01-01

The planned HL-LHC (High Luminosity LHC) is being designed to maximise the physics potential of the LHC with 10 years of operation at instantaneous luminosities of 7.5x1034cm−2s−1. A consequence of this increased luminosity is the expected radiation damage requiring the tracking detectors to withstand hadron equivalences to over 1x1015 1 MeV neutron equivalent per cm2 in the ATLAS Strips system. The silicon strip tracker exploits the concept of modularity. Fast readout electronics, deploying 130nm CMOS front-end electronics are glued on top of a silicon sensor to make a module. The radiation hard n-in-p micro-strip sensors used have been developed by the ATLAS ITk Strip Sensor collaboration and produced by Hamamatsu Photonics. A series of tests were performed at the DESY-II and CERN SPS test beam facilities to investigate the detailed performance of a strip module with both 2.5cm and 5cm length strips before and after irradiation with 8x1014neqcm−2 protons and a total ionising dose of 37.2MRad. The DURA...

Chemical changes in food packaging resulting from ionizing irradiation

International Nuclear Information System (INIS)

Thayer, D.W.

1988-01-01

Recent approvals of food irradiation processes by the U.S. Food and Drug Administration have led to a search for packaging approved for use with ionizing radiation. Though 13 packaging materials were approved several years ago as food contactants for gamma irradiation up to 10 kGy at refrigeration temperatures and 4 packaging materials were approved for up to 60 kGy at cryogenic temperatures, no currently used packaging is approved for irradiated foods. Extensive research was conducted by the U.S. Army and others on the suitability of both flexible packaging and metal cans for packaging irradiated foods. The results of the studies of packaging for irradiated foods will be described and discussed in context of currently used packaging materials for non-irradiated meats and poultry

Performance of the ALIBAVA portable readout system with irradiated and non-irradiated microstrip silicon sensors

International Nuclear Information System (INIS)

Marco-Hernadez, R.

2009-01-01

A readout system for microstrip silicon sensors has been developed as a result of collaboration among the University of Liverpool, the CNM of Barcelona and the IFIC of Valencia. The name of this collaboration is ALIBAVA and it is integrated in the RD50 Collaboration. This system is able to measure the collected charge in one or two microstrip silicon sensors by reading out all the channels of the sensor(s), up to 256, as an analogue measurement. The system uses two Beetle chips to read out the detector(s). The Beetle chip is an analogue pipelined readout chip used in the LHCb experiment. The system can operate either with non-irradiated and irradiated sensors as well as with n-type and p-type microstrip silicon sensors. Heavily irradiated sensors will be used at the SLHC, so this system is being to research the performance of microstrip silicon sensors in conditions as similar as possible to the SLHC operating conditions. The system has two main parts: a hardware part and a software part. The hardware part acquires the sensor signals either from external trigger inputs, in case of a radioactive source setup is used, or from a synchronised trigger output generated by the system, if a laser setup is used. This acquired data is sent by USB to be stored in a PC for a further processing. The hardware is a dual board based system. The daughterboard is a small board intended for containing two Beetle readout chips as well as fan-ins and detector support to interface the sensors. The motherboard is intended to process the data, to control the whole hardware and to communicate with the software by USB. The software controls the system and processes the data acquired from the sensors in order to store it in an adequate format file. The main characteristics of the system will be described. Results of measurements acquired with n-type and p-type irradiated and non-irradiated detectors using both the laser and the radioactive source setup will be also presented and discussed

Defect structures in YBa/sub 2/Cu/sub 3/O/sub 7-x/ produced by electron irradiation

International Nuclear Information System (INIS)

Kirk, M.A.; Baker, M.C.; Liu, J.Z.; Lam, D.J.; Weber, H.W.

1988-01-01

Defect structures in YBa/sub 2/Cu/sub 3/O/sub 7-x/ produced by electron irradiation at 300 K were investigated by transmission electron microscopy. Threshold energies for the production of visible defects were determined to be 152 keV and 131 keV (+- 7 keV) in directions near the a and b (b>a) axes (both perpendicular to c, the long axis in the orthorhombic structure), respectively. During above threshold irradiations in an electron flux of 3x10/sup 18/ cm/sup -2/ s/sup -1/, extended defects were observed to form and grow to sizes of 10-50 nm over 1000 s in material thickness 20-200 nm. Such low electron threshold energies suggest oxygen atom displacements with recoil energies near 20 eV. The observation of movement of twin boundaries during irradiation just above threshold suggests movement of the basal plane oxygen atoms by direct displacement or defect migration processes. Crystals irradiated above threshold were observed after about 24 hours to have transformed to a structure heavily faulted on planes perpendicular to the c axis

NuSTAR observations of heavily obscured quasars at z ~ 0.5

DEFF Research Database (Denmark)

Lansbury, G. B.; Alexander, D. M.; Del Moro, A.

2014-01-01

We present NuSTAR hard X-ray observations of three Type 2 quasars at z ≈ 0.4-0.5, optically selected from the Sloan Digital Sky Survey. Although the quasars show evidence for being heavily obscured, Compton-thick systems on the basis of the 2-10 keV to [O III] luminosity ratio and multiwavelength...

Hardening and microstructural evolution of A533b steels irradiated with Fe ions and electrons

Energy Technology Data Exchange (ETDEWEB)

Watanabe, H., E-mail: watanabe@riam.kyushu-u.ac.jp [Research Institute for Applied Mechanics, Kyushu University, 6-1, Kasuga-kouenn, Kasugashi, Fukuoka, 816-8580 (Japan); Arase, S. [Interdisciplinary Graduate School of Kyushu University, 6-1, Kasuga-kouenn, Kasugashi, Fukuoka, 816-8580 (Japan); Yamamoto, T.; Wells, P. [Dept. Chemical Engineering, UCSB Engineering II, RM3357, Santa Barbara, CA, 93106-5080 (United States); Onishi, T. [Interdisciplinary Graduate School of Kyushu University, 6-1, Kasuga-kouenn, Kasugashi, Fukuoka, 816-8580 (Japan); Odette, G.R. [Dept. Chemical Engineering, UCSB Engineering II, RM3357, Santa Barbara, CA, 93106-5080 (United States)

2016-04-01

Radiation hardening and embrittlement of A533B steels is heavily dependent on the Cu content. In this study, to investigate the effect of copper on the microstructural evolution of these materials, A533B steels with different Cu levels were irradiated with 2.4 MeV Fe ions and 1.0 MeV electrons. Ion irradiation was performed from room temperature (RT) to 350 °C with doses up to 1 dpa. At RT and 290 °C, low dose (<0.1 dpa) hardening trend corresponded with ΔH ∝ (dpa){sup n}, with n initially approximately 0.5 and consistent with a barrier hardening mechanism, but saturating at ≈0.1 dpa. At higher dose levels, the radiation-induced hardening exhibited a strong Cu content dependence at 290 °C, but not at 350 °C. Electron irradiation using high-voltage electron microscopy revealed the growth of interstitial-type dislocation loops and enrichment of Ni, Mn, and Si in the vicinities of pre-existing dislocations at doses for which the radiation-induced hardness due to ion irradiation was prominent.

Silicon/HfO2 interface: Effects of proton irradiation

International Nuclear Information System (INIS)

Maurya, Savita; Radhakrishna, M.

2015-01-01

Substrate oxide interfaces are of paramount importance in deciding the quality of the semiconductor devices. In this work we have studied how 200 keV proton irradiation affects the interface of a 13 nm thick, atomic layer deposited hafnium dioxide on silicon substrate. Pre- and post-irradiation electrical measurements are used to quantify the effect of proton irradiation for varying electrode geometries. Proton irradiation introduces positive charge in the oxide and at the interface of Si/HfO 2 interface. The gate current is not very much affected under positive injection since the induced positive charge is compensated by the injected electrons. Current voltage characteristics under negative bias get affected by the proton irradiation

Chronic radiation exposure as an ecological factor: Hypermethylation and genetic differentiation in irradiated Scots pine populations.

Science.gov (United States)

Volkova, P Yu; Geras'kin, S A; Horemans, N; Makarenko, E S; Saenen, E; Duarte, G T; Nauts, R; Bondarenko, V S; Jacobs, G; Voorspoels, S; Kudin, M

2018-01-01

Genetic and epigenetic changes were investigated in chronically irradiated Scots pine (Pinus sylvestris L.) populations from territories that were heavily contaminated by radionuclides as result of the Chernobyl Nuclear Power Plant accident. In comparison to the reference site, the genetic diversity revealed by electrophoretic mobility of AFLPs was found to be significantly higher at the radioactively contaminated areas. In addition, the genome of pine trees was significantly hypermethylated at 4 of the 7 affected sites. Copyright © 2017 Elsevier Ltd. All rights reserved.

RECH-1 test fuel irradiation status report

International Nuclear Information System (INIS)

Marin, J.; Lisboa, J.; Olivares, L.; Chavez, J.

2005-01-01

Since May 2003, one RECH-1 fuel element has been submitted to irradiation at the HFR-Petten, Holland. By November 2004 the irradiation has achieved its pursued goal of 55% burn up. This irradiation qualification service will finish in the year 2005 with PIE tests, as established in a contractual agreement between the IAEA, NRG, and CCHEN. This report presents the objectives and the current results of this fuel qualification under irradiation. Besides, a brief description of CHI/4/021, IAEA's Technical Cooperation Project that has supported this irradiation test, is also presented here. (author)

Irradiated recycled plastic as a concrete additive for improved chemo-mechanical properties and lower carbon footprint.

Science.gov (United States)

Schaefer, Carolyn E; Kupwade-Patil, Kunal; Ortega, Michael; Soriano, Carmen; Büyüköztürk, Oral; White, Anne E; Short, Michael P

2018-01-01

Concrete production contributes heavily to greenhouse gas emissions, thus a need exists for the development of durable and sustainable concrete with a lower carbon footprint. This can be achieved when cement is partially replaced with another material, such as waste plastic, though normally with a tradeoff in compressive strength. This study discusses progress toward a high/medium strength concrete with a dense, cementitious matrix that contains an irradiated plastic additive, recovering the compressive strength while displacing concrete with waste materials to reduce greenhouse gas generation. Compressive strength tests showed that the addition of high dose (100kGy) irradiated plastic in multiple concretes resulted in increased compressive strength as compared to samples containing regular, non-irradiated plastic. This suggests that irradiating plastic at a high dose is a viable potential solution for regaining some of the strength that is lost when plastic is added to cement paste. X-ray Diffraction (XRD), Backscattered Electron Microscopy (BSE), and X-ray microtomography explain the mechanisms for strength retention when using irradiated plastic as a filler for cement paste. By partially replacing Portland cement with a recycled waste plastic, this design may have a potential to contribute to reduced carbon emissions when scaled to the level of mass concrete production. Copyright © 2017 Elsevier Ltd. All rights reserved.

Morphological differences in the response of mouse small intestine to radiobiologically equivalent doses of X and neutron irradiation

International Nuclear Information System (INIS)

Carr, K.E.; Hamlet, R.; Nias, A.H.; Watt, C.

1984-01-01

A scale has been developed to describe the effects of radiation on small intestinal villi. The scale has been used to compare the damage done to the villi in the period 0-5 days after irradiation by X-irradiation or neutron irradiation, using 10 Gy X-rays and 5 Gy neutrons, doses which are radiobiologically equivalent when assessed by the microcolony assay method. Use of the scale indicates that the damage done to the villi by neutrons is greater than that produced by X-rays. This has implications for the interpretation of radiobiological equivalent doses (R.B.E.). Resin light microscopy and transmission electron microscopy (T.E.M.) have also been used to examine small intestinal damage after 10 Gy X-irradiation and 5 Gy neutron irradiation. Differences include variations in crypt shape, mitotic activity and the proportion of crypts which are heavily parasitised. As well as the differences in villous shape which have been reflected in the different values on the scoring system, there are also variations in the response of the constituent cells of the epithelial compartment of the villi. In general, the effect of the neutron irradiation is more severe than that of the X-rays, particularly as would be suggested by a simple quantitation of crypt regeneration

Food Irradiation In Vietnam And Japan

International Nuclear Information System (INIS)

Tamikazy Kume

2011-01-01

In 2008, Japan Atomic Energy Commission of Cabinet Office performed the study of current status of food irradiation in the world. The results showed that the total quantity of irradiated foods in 2005 was 405,000 tons. Seven main countries for food irradiation were China, USA, Ukraine, Brazil, South Africa, Vietnam and Japan. In Japan, only the potato irradiation for sprout inhibition is continued more than 35 years since 1974 but the quantity is decreasing. On the other hand, the food irradiation of Vietnam has been developed rapidly in a short time to export the frozen seafood and fruit. This paper shows the status of food irradiation in Vietnam and Japan, and the progress in both countries after 2005. (author)

Low field leakage current on ultra-thin gate oxides after ion or electron beam irradiations; Courant de fuite aux champs faibles d'oxydes ultra-minces apres irradiations avec des faisceaux d'ions et d'electrons

Energy Technology Data Exchange (ETDEWEB)

Ceschia, M.; Paccagnella, A.; Sandrin, S. [Universita di Padova, Dipt. di Elettronica e Informatica, Padova (Italy); Paccagnella, A. [Istituto Nazionale per la Fisica della Materia, INFM, Unita di Padova (Italy); Ghidini, G. [ST-Microelectronics, Agrate Brianza (Italy); Wyss, J. [Universita di Padova, Dipt. di Fisica, Padova (Italy)

1999-07-01

In contemporary CMOS 0.25-{mu}m technologies, the MOS gate oxide (thickness {approx_equal} 5 nm) shows a low-field leakage current after radiation stresses, i.e. the radiation induced leakage current (RILC). RILC is generally attributed to a trap assisted tunneling (TAT) of electrons through neutral oxide traps generated by radiation stress. RILC has been investigated on ultra-thin oxides irradiated with 158 MeV {sup 28}Si ions or 8 MeV electrons. 3 main results are worth being quoted: 1) ion or electron beam irradiation can produce RILC with similar characteristics. Even the dose dependence of RILC is similar in the 2 cases, despite the large LET difference (about a factor of 10{sup +4}), 2) RILC is not a constant as a function of time, it tends to decrease when an oxide field (few MV/cm) is applied for (tens of) thousands seconds. On the other hand, RILC stays constant in devices kept at low bias, and 3) if a pulsed gate voltage is applied during irradiation, RILC is reduced with respect to the zero-field case. (A.C.)

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.

Neutron irradiation effects on plasma facing materials

International Nuclear Information System (INIS)

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

2000-01-01

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

Consumer acceptance of irradiated foods

International Nuclear Information System (INIS)

Feenstra, M.H.; Scholten, A.H.

1991-01-01

Although the first experiments on food irradiation were carried out in 1916 in Sweden, food irradiation, is for consumers, a relatively new technology. From the sixties food irradiation has been applied more and more, so that the consumer movement has become alert to this technology. Since then a lot of controversies have arisen in the literature about wholesomeness, safety, effects, etc. Food irradiation is currently permitted on a small scale in about 30 countries; in some countries or states food irradiation has been put under a ban (e.g. Australia, New Zealand, New Jersey). The World Health Organization (WHO) and the Food and Agriculture Organization of the United Nations (FAO) have, however, chosen food irradiation as a safe and sound method for preserving and improving the safety of food. Reactions on the part of the consumer organizations of many countries are however not in favour of or are even opposed to food irradiation. In this chapter consumer acceptance related to technological developments is described, then the convergence of the consumer movement on public opinion and concern on food irradiation is discussed. The need for labelling of irradiated food products is discussed and finally recommendations are given of ways to change consumers attitudes to food irradiation. (author)

On-line monitoring of base current and forward emitter current gain of the voltage regulator's serial pnp transistor in a radiation environment

Directory of Open Access Journals (Sweden)

Vukić Vladimir Đ.

2012-01-01

Full Text Available A method of on-line monitoring of the low-dropout voltage regulator's operation in a radiation environment is developed in this paper. The method had to enable detection of the circuit's degradation during exploitation, without terminating its operation in an ionizing radiation field. Moreover, it had to enable automatic measurement and data collection, as well as the detection of any considerable degradation, well before the monitored voltage regulator's malfunction. The principal parameters of the voltage regulator's operation that were monitored were the serial pnp transistor's base current and the forward emitter current gain. These parameters were procured indirectly, from the data on the voltage regulator's load and quiescent currents. Since the internal consumption current in moderately and heavily loaded devices was used, the quiescent current of a negligibly loaded voltage regulator of the same type served as a reference. Results acquired by on-line monitoring demonstrated marked agreement with the results acquired from examinations of the voltage regulator's maximum output current and minimum dropout voltage in a radiation environment. The results were particularly consistent in tests with heavily loaded devices. Results obtained for moderately loaded voltage regulators and the risks accompanying the application of the presented method, were also analyzed.

The effect of charge collection recovery in silicon p-n junction detectors irradiated by different particles

International Nuclear Information System (INIS)

Verbitskaya, E.; Abreu, M.; Anbinderis, P.; Anbinderis, T.; D'Ambrosio, N.; Boer, W. de; Borchi, E.; Borer, K.; Bruzzi, M.; Buontempo, S.; Casagrande, L.; Chen, W.; Cindro, V.; Dezillie, B.; Dierlamm, A.; Eremin, V.; Gaubas, E.; Gorbatenko, V.; Granata, V.; Grigoriev, E.; Grohmann, S.; Hauler, F.; Heijne, E.; Heising, S.; Hempel, O.; Herzog, R.; Haerkoenen, J.; Ilyashenko, I.; Janos, S.; Jungermann, L.; Kalesinskas, V.; Kapturauskas, J.; Laiho, R.; Li, Z.; Mandic, I.; De Masi, Rita; Menichelli, D.; Mikuz, M.; Militaru, O.; Niinikoski, T.O.; O'Shea, V.; Pagano, S.; Palmieri, V.G.; Paul, S.; Perea Solano, B.; Piotrzkowski, K.; Pirollo, S.; Pretzl, K.; Rato Mendes, P.; Ruggiero, G.; Smith, K.; Sonderegger, P.; Sousa, P.; Tuominen, E.; Vaitkus, J.; Da Via, C.; Wobst, E.; Zavrtanik, M.

2003-01-01

The recovery of the charge collection efficiency (CCE) at low temperatures, the so-called 'Lazarus effect', was studied in Si detectors irradiated by fast reactor neutrons, by protons of medium and high energy, by pions and by gamma-rays. The experimental results show that the Lazarus effect is observed: (a) after all types of irradiation; (b) before and after space charge sign inversion; (c) only in detectors that are biased at voltages resulting in partial depletion at room temperature. The experimental temperature dependence of the CCE for proton-irradiated detectors shows non-monotonic behaviour with a maximum at a temperature defined as the CCE recovery temperature. The model of the effect for proton-irradiated detectors agrees well with that developed earlier for detectors irradiated by neutrons. The same midgap acceptor-type and donor-type levels are responsible for the Lazarus effect in detectors irradiated by neutrons and by protons. A new, abnormal 'zigzag'-shaped temperature dependence of the CCE was observed for detectors irradiated by all particles (neutrons, protons and pions) and by an ultra-high dose of γ-rays, when operating at low bias voltages. This effect is explained in the framework of the double-peak electric field distribution model for heavily irradiated detectors. The redistribution of the space charge region depth between the depleted regions adjacent to p + and n + contacts is responsible for the 'zigzag'- shaped curves. It is shown that the CCE recovery temperature increases with reverse bias in all detectors, regardless of the type of radiation

Post irradiation examination technology exchange

International Nuclear Information System (INIS)

Sozawa, Shizuo; Ito, Masayasu; Taguchi, Taketoshi; Nakagawa, Tetsuya; Lee, Hyung-Kwon

2012-01-01

Under the KAERI and JAEA agreement, in a part of the program 18 (Post Irradiation Examination (PIE) and Evaluation Technique of Irradiated Materials), an eddy current test was proposed as a round robin test, and it has been being progressed in both organizations in order to enhance the post irradiation examination technology. Up to now, several data are obtained by both PIE facilities. In this paper, the round robin test program is shown, and also shown obtained data with discussion from applicability as a nondestructive test in the hot cell. (author)

Irradiation of Northwest agricultural products

International Nuclear Information System (INIS)

Eakin, D.E.; Tingey, G.L.; Anderson, D.B.; Hungate, F.P.

1985-01-01

Irradiation of food for disinfestation and preservation is increasing in importance because of increasing resrictions on various chemical treatments. Irradiation treatment is of particular interest in the Northwest because of a growing supply of agricultural products and the need to develop new export markets. Several products have, or could potentially have, significant export markets if stringent insect control procedures are developed and followed. Due to the recognized potential benefits of irradiation, Pacific Northwest Laboratory (PNL) is conducting this program to evaluate the benefits of using irradiation on Northwest agricultural products under the US Department of Energy (DOE) Defense Byproducts Production and Utilization Program. Commodities currently included in the program are cherries, apples, asparagus, spices, hay, and hides

Irradiation of Northwest agricultural products

International Nuclear Information System (INIS)

Eakin, D.E.; Tingey, G.L.

1985-02-01

Irradiation of food for disinfestation and preservation is increasing in importance because of increasing restrictions on various chemical treatments. Irradiation treatment is of particular interest in the Northwest because of a growing supply of agricultural products and the need to develop new export markets. Several products have, or could potentially have, significant export markets if stringent insect control procedures are developed and followed. Due to the recognized potential benefits of irradiation, Pacific Northwest Laboratory (PNL) is conducting this program to evaluate the benefits of using irradiation on Northwest agricultural products under the US Department of Energy (DOE) Defense Byproducts Production and Utilization Program. Commodities currently included in the program are cherries, apples, asparagus, spices, hay, and hides

Fuel irradiation experience at Halden

International Nuclear Information System (INIS)

Vitanza, Carlo

1996-01-01

The OECD Halden Reactor Project is an international organisation devoted to improved safety and reliability of nuclear power station through an user-oriented experimental programme. A significant part of this programme consists of studies addressing fuel performance issues in a range of conditions realised in specialised irradiation. The key element of the irradiation carried out in the Halden reactor is the ability to monitor fuel performance parameters by means of in-pile instrumentation. The paper reviews some of the irradiation rigs and the related instrumentation and provides examples of experimental results on selected fuel performance items. In particular, current irradiation conducted on high/very high burn-up fuels are reviewed in some detail

Swelling and outgassing of heavily-irradiated lithium hydride

International Nuclear Information System (INIS)

Souers, P.C.; Ackerman, F.J.; Biel, T.J.; Bigwood, J.; Brite, V.; Christensen, L.D.; Folkers, C.L.; Gede, V.; Griffith, C.M.; Huss, E.B.; Lindahl, R.; McCreary, T.; Otsuki, H.H.; Pond, R.L.; Snider, G.D.; Stanhope, C.; Stump, R.K.; Vanderhoofven, F.; Tsugawa, R.T.; Anderson, J.L.; Carstens, D.W.H.; Drumhiller, W.L.; Lewis, W.B.; Nasise, J.E.; Pretzel, F.E.; Szklarz, E.G.; Vier, D.T.; Bowman, R.C. Jr.; Attalla, A.

1988-01-01

Twenty-two years worth of data on lithium deuteride-tritide (Li(D, T)) from three national laboratories is presented. The percent linear swelling and the outgassing of hydrogen isotopes and 3 He for samples stored at 243 to 438 K are presented in summary tables. In some cases, up to a full half-life of tritium (12 years) has been spent in the study. Initial tritium concentrations range from 2 to 98 at%. The precision of the swelling is considered, and the evidence is ambiguous as to whether temperature cycling and handling affects swelling. The early outgassing is all hydrogen, but it turns to helium at long lines. The outgassing levels out for each sample but the amount outgassed varies wildly from sample to sample. At linear swellings beyond 11%, behavior becomes erratic. A maximum linear swelling of 23% is seen for one sample at 5000 days. (orig.)

Irradiation effects in superconductor oxides. Effets d'irradiation dans les oxydes supraconducteurs

Energy Technology Data Exchange (ETDEWEB)

Rullier-Albenque, F; Konczykowski, M [CEA-Ecole Polytechnique, 91 - Palaiseau (France). Lab. d' Etudes des Solides Irradies

1993-01-01

Several effects of irradiation on the 92 K - oxide superconductor YBa[sub 2]Cu[sub 3]O[sub 7] are reported. Whatever irradiation type, the critical temperature T[sub c] is found to decrease and the resistivity to increase. At sufficiently high damage levels, YBa[sub 2]Cu[sub 3]O[sub 7] is no longer superconducting and even displays a semiconducting-like behaviour. The alterations of superconducting properties are clearly related to oxygen defects - in the CuO[sub 2] planes or CuO chains... but we have shown experimentally that copper defects are also important. Magnetic properties of YBa[sub 2]Cu[sub 3]O[sub 7] in mixed state are also very sensitive to irradiation. By pinning the flux lines, irradiation defects can considerably increase the critical current density j[sub c]. At present, irradiations by highly energetic heavy ions (6 GeV Pb for instance), which produce cylindrical tubes of amorphous material (latent tracks) throughout the whole thickness of the samples, are probably the most efficient way to enhance j[sub c]. (Author). 18 refs., 7 figs.

Vaccination of bovines against Schistosomiasis japonica with highly irradiated schistosomula in China

International Nuclear Information System (INIS)

Hsue, S.Y.; Xu, S.T.; He, Y.X.; Shi, F.H.; Shen, W.; Hsue, H.F.; Osborne, J.W.; Clarke, W.R.

1984-01-01

Vaccination of Chinese bovines (cattle and buffaloes) against Schistosomiasis japonica with 36 kR gamma-irradiated schistosomula was done for laboratory challenge and for field trials in China. Altogether, 61 bovines were used. All experimental animals were vaccinated 2-3 times with 10,000 irradiated schistosomula per time. For the laboratory challenge, all experimental and control cattle were challenged with 500 normal cercariae and each buffalo, with 2,000 cercariae. The laboratory-challenged bovines were killed after 54-57 days of challenge; the bovines for the field trial in the lightly endemic area, after 5 months in the field; and the bovines for the field trial in the heavily endemic area, after 58-63 days. When the animals were killed, the number of mature worms in the vaccinated (experimental) and non-vaccinated (control) animals was recorded and the percentage of worm reduction in each group was calculated. The first group, consisting of three vaccinated and three non-vaccinated cattle, was given a laboratory challenge; the worm reduction was 71.6%. The second group, consisting of two vaccinated and three non-vaccinated buffaloes, was also given a laboratory challenge; the worm reduction was 74.4%. The third group, consisting of seven vaccinated and eight non-vaccinated buffaloes, was utilized in a field trial in a lightly endemic area; the worm reduction was 75.6%. The fourth group, consisting of eight vaccinated and nine non-vaccinated cattle, and the fifth group, consisting of nine vaccinated and nine non-vaccinated buffaloes, were pastured in a heavily endemic area. The worm reduction was 65.1% in the fourth group and 75.7% in the fifth group

Present and future of food irradiation in China

International Nuclear Information System (INIS)

Chen Hao; Cai Jiming; Pan Pingchuan; Liu Ge

2006-01-01

The treatment of foods and agricultural products by irradiation technology in China has become an increasingly accepted practice and has been recognized as a public health intervention measure for controling pathogenic microbes and pests on foods since early 1980s. This paper gives an outline on the history and the current status of food irradiation in China, including the research interest, commercial application, public acceptance, regulations and hygienic standards of irradiated foods, and the irradiation facilities for food irradiation. The newly finished or scheduled irradiation facilities in China up to 2007 are introduced. And problems with the food irradiation studies, especially in analysis of food quality during irradiation, the implementation of GMP and HACCP in the food irradiation production and harmonization of food irradiation regulations with international standards, are also discussed. (authors)

Current status of the EPR method to detect irradiated food

International Nuclear Information System (INIS)

Desrosiers, M.F.

1996-01-01

This review gives a brief outline of the principles of the EPR detection method for irradiated foods by food type. For each food type, the scope, limitations and status of the method are given. The extensive reference list aims to include all which define the method, as well as some rarely cited works of historical importance. (author)

Conductivity and superconductivity in heavily vacant diamond

Directory of Open Access Journals (Sweden)

S A Jafari

2009-08-01

Full Text Available   Motivated by the idea of impurity band superconductivity in heavily Boron doped diamond, we investigate the doping of various elements into diamond to address the question, which impurity band can offer a better DOS at the Fermi level. Surprisingly, we find that the vacancy does the best job in producing the largest DOS at the Fermi surface. To investigate the effect of disorder in Anderson localization of the resulting impurity band, we use a simple tight-binding model. Our preliminary study based on the kernel polynomial method shows that the impurity band is already localized at the concentration of 10-3. Around the vacancy concentration of 0.006 the whole spectrum of diamond becomes localized and quantum percolation takes place. Therefore to achieve conducting bands at concentrations on the scale of 5-10 percent, one needs to introduce correlations such as hopping among the vacancies .

Food irradiation and the consumer

International Nuclear Information System (INIS)

Thomas, P.A.

1990-01-01

The poster presents a review of research work undertaken on the perception and understanding that consumers have of food irradiation. Food irradiation is not a revolutionary new food processing technique, in fact it is probably one of the most investigated methods presently available. Many countries such as Belgium, France, Denmark, Italy, Spain, the Netherlands and the United States of America permit food irradiation. In Britain it is presently banned although this is currently under review. Awareness of food irradiation by the general public in Britain, although not extensively researched would appear to be increasing, especially in the light of recent media coverage. New quantitative and qualitative work indicates that the general public are concerned about the safety and effectiveness of food irradiation. Research has shown that a large proportion of consumers in Britain, if given the opportunity to purchase irradiated food, would not do so. Further exploration into this response revealed the fact that consumers are confused over what food irradiation is. In addition, there is concern over the detection of irradiated food. The views presented in this paper, of the consumer reaction to irradiated food are of great importance to those involved in the food industry and industries allied to it, which are ultimately dependent on the consumer for their commercial survival. (author)

X-ray irradiation of RC-MAP pre-stored for various numbers of days. Effect of X-ray irradiation on RC-MAP and reuse of RC-MAP after irradiation

International Nuclear Information System (INIS)

Yamada, Naotomo; Nagumo, Fumio; Kawasaki, Seiji; Matsuzaki, Miwako; Tadano, Jutaro

1995-01-01

X-ray irradiation is currently in wide use as a means of preventing post-transfusion graft-versus-host disease (PT-GVHD). In this study, we evaluated the effects of X-ray irradiation on RC-MAP pre-stored for various numbers of days, and assessed how long irradiated RC-MAP can be stored. RC-MAP was irradiated at a dosage of 15 Gy at 1, 7, 14, 21 or 28 days after blood collection. These specimens were referred to as group I, II, III, IV and V (X-ray-irradiated groups), respectively. Non-irradiated RC-MAP was used as the control. Results showed that plasma K concentration increased after X-ray irradiation. It is therefore advisable that RC-MAPs be used immediately in infants and in renal failure. However, to maximize the efficiency of blood product use, it seemed possible that groups I and II could be used within two weeks after irradiation, and group III within one week. On the basis of this increase in K concentration, however, groups IV and V plasma should be used immediately after irradiation. (author)

Tensile stress corrosion cracking of type 304 stainless steel irradiated to very high dose

Energy Technology Data Exchange (ETDEWEB)

Chung, H. M.; Ruther, W. E.; Strain, R. V.; Shack, W. J.

2001-09-01

Certain safety-related core internal structural components of light water reactors, usually fabricated from Type 304 or 316 austenitic stainless steels (SSs), accumulate very high levels of irradiation damage (20--100 displacement per atom or dpa) by the end of life. The data bases and mechanistic understanding of, the degradation of such highly irradiated components, however, are not well established. A key question is the nature of irradiation-assisted intergranular cracking at very high dose, i.e., is it purely mechanical failure or is it stress-commotion cracking? In this work, hot-cell tests and microstructural characterization were performed on Type 304 SS from the hexagonal fuel can of the decommissioned EBR-11 reactor after irradiation to {approximately}50 dpa at {approximately}370 C. Slow-strain-rate tensile tests were conducted at 289 C in air and in water at several levels of electrochemical potential (ECP), and microstructural characteristics were analyzed by scanning and transmission electron microcopies. The material deformed significantly by twinning and exhibited surprisingly high ductility in air, but was susceptible to severe intergranular stress corrosion cracking (IGSCC) at high ECP. Low levels of dissolved O and ECP were effective in suppressing the susceptibility of the heavily irradiated material to IGSCC, indicating that the stress corrosion process associated with irradiation-induced grain-boundary Cr depletion, rather than purely mechanical separation of grain boundaries, plays the dominant role. However, although IGSCC was suppressed, the material was susceptible to dislocation channeling at low ECP, and this susceptibility led to poor work-hardening capability and low ductility.

Space charge dynamic of irradiated cyanate ester/epoxy at cryogenic temperatures

Science.gov (United States)

Wang, Shaohe; Tu, Youping; Fan, Linzhen; Yi, Chengqian; Wu, Zhixiong; Li, Laifeng

2018-03-01

Glass fibre reinforced polymers (GFRPs) have been widely used as one of the main electrical insulating structures for superconducting magnets. A new type of GFRP insulation material using cyanate ester/epoxy resin as a matrix was developed in this study, and the samples were irradiated by Co-60 for 1 MGy and 5 MGy dose. Space charge distributed within the sample were tested using the pulsed electroacoustic method, and charge concentration was found at the interfaces between glass fibre and epoxy resin. Thermally stimulated current (TSC) and dc conduction current were also tested to evaluate the irradiation effect. It was supposed that charge mobility and density were suppressed at the beginning due to the crosslinking reaction, and for a higher irradiation dose, molecular chain degradation dominated and led to more sever space charge accumulation at interfaces which enhance the internal electric field higher than the external field, and transition field for conduction current was also decreased by irradiation. Space charge dynamic at cryogenic temperature was revealed by conduction current and TSC, and space charge injection was observed for the irradiated samples at 225 K, which was more obvious for the irradiated samples.

The future of irradiation applications on earth and in space

International Nuclear Information System (INIS)

Karel, M.

1989-01-01

This article discusses the current status of food irradiation in the United States, what needs to be done to establish food irradiation on a truly commercial basis, and prospects for the use of food irradiation in space

Yield strength of a heavily drawn Cu-20% Nb filamentary microcomposite

International Nuclear Information System (INIS)

Hong, S.I.

1998-01-01

It has been well documented that heavily-drawn, copper-niobium microcomposites possess high strength and high conductivity. Since niobium has little solubility in copper, the conductivity of the copper is not strongly affected by the addition of niobium. Following extensive mechanical deformation of Cu-Nb, niobium dendrites transform into fine niobium ribbons as a result of the niobium texture upon drawing. This nanostructure contributes to the ultrahigh strength of Cu-Nb microcomposites. The strength of heavily deformed Cu-Nb exceeds that predicted by the rule-of-mixtures (ROM), and a fundamental understanding of the strengthening mechanisms involved has been the subject of much discussion. Spitzig and his coworkers suggests a barrier strengthening model while Funkenbusch and Courtney believe that stored dislocations have a role in substructural hardening. Hangen and Raabe recently proposed an analytical model for the calculation of the yield strength of Cu-Nb microcomposite. The model of Hangen and Raabe and that of Spitzig and his coworkers have a great deal of resemblance since both models attribute the strength to the difficulty of propagating plastic flow through the interface. The purpose of this study was to enhance the understanding of the strengthening mechanisms associated with Cu-Nb microcomposites by examining the previous studies on mechanical and microstructural stability of Cu-based microcomposites

Radiation research of materials using irradiation capsules

International Nuclear Information System (INIS)

Chamrad, B.

1976-01-01

The methods are briefly characterized of radiation experiments on the WWR-S research reactor. The irradiation capsule installed in the reactor including the electronic instrumentation is described. Irradiated samples temperature is stabilized by an auxiliary heat source placed in the irradiation space. The electronic control equipment of the system is automated. In irradiation experiments, experimental and operating conditions are recorded by a digital measuring centre with electric typewriter and paper tape data recording and by an analog compensating recorder. The irradiation experiment control system controls irradiated sample temperature, the supply current size and the heating element temperature of the auxiliary stabilizing source, inert and technological pressures of the capsule atmosphere and the thermostat temperature of the thermocouple junctions. (O.K.)

Saturation behavior of irradiation hardening in F82H irradiated in the HFIR

Energy Technology Data Exchange (ETDEWEB)

Hirose, T. [Blanket Engineering Group, Japan Atomic Energy Agency, Naka, Ibaraki (Japan); Shiba, K.; Tanigawa, H.; Ando, M. [Japan Atomic Energy Agency, Tokai-mura, Naga-gun, Ibaraki-ken (Japan); Klueh, R.L. [Oak Ridge National Laboratory, TN (United States); Stoller, R. [ORNL - Oak Ridge National Laboratory, Materials Science and Technology Div., Oak Ridge, AK TN (United States)

2007-07-01

Full text of publication follows: Post irradiation tensile tests on reduced activation ferritic/martensitic steel, F82H have been conducted over the past two decades using Japan Materials Testing Reactor (JMTR) of JAEA, and Fast Flux Testing Facility (FFTF) of PNNL and High Flux Isotope Reactor (HFIR) of ORNL, USA, under Japan/US collaboration programs. According to these results, F82H does not demonstrate irradiation hardening above 673 K up to 60 dpa. The current study has been concentrated on hardening behavior at temperature around 573 K. A series of low temperature irradiation experiment has been conducted at the HFIR under the international collaborative research between JAEA/US-DOE. In this collaboration, the irradiation condition is precisely controlled by the well matured capsule designing and instrumentation. This paper summarizes recent results of the irradiation experiments focused on F82H and its modified steels compared with the irradiation properties database on F82H. Post irradiation tensile tests have been conducted on the F82H and its modified steels irradiated at 573 K and the dose level was up to 25 dpa. According to these results, irradiation hardening of F82H is saturated by 9 dpa and the as-irradiated 0.2 % proof stress is less than 1 GPa at ambient temperature. The deterioration of total elongation was also saturated by 9 dpa irradiation. The ductility of some modified steels which showed larger total elongation than that of F82H before irradiation become the same level as that of standard F82H steel after irradiation, even though its magnitude of irradiation hardening is smaller than that of F82H. This suggests that the more ductile steel demonstrates the more ductility loss at this temperature, regardless to the hardening level. The difference in ductility loss behavior between various tensile specimens will be discussed as the ductility could depend on the specimen dimension. (authors)

Consumer attitude toward food irradiation

International Nuclear Information System (INIS)

Bruhn, C.M.M.

1986-01-01

Consumer attitudes toward food irradiation were evaluated. The influence of educational efforts on consumer concern for the safety of irradiated products and willingness to buy irradiated foods were measured. Demographic and psychological factors were studied in relation to attitudes. An educational leaflet describing current scientific information regarding the safety, advantages, and disadvantages of food irradiation was developed and used in two studies evaluating attitude change. In the first study, attitude change among two groups of consumers with different philosophic orientations was measured. In a second study, the effectiveness of an educational leaflet received through the mail and a poster display were examined. In a third study response to food irradiation was related to value hierarchy, locus of control, innovativeness, and demographic parameters. Initially, subjects showed a higher concern for other areas of food safety, particularly the use of chemicals and sprays on food, than toward food irradiation. After educational efforts, conventional consumers expressed minor concern toward irradiation whereas ecologically sensitive alternative consumers obtained from a food cooperative expressed major concern. A knowledgeable discussion leader lowered irradiation concern among conventional consumers. In contrast, concern among alternative consumers did not diminish when given the opportunity to discuss safety issues with a knowledgeable person

Theoretical investigation of the heavily-doped semiconductor aspect of ultra-dilute GaAsN

Science.gov (United States)

Sukpitak, Jessada; Sa-yakanit, Virulh

2015-12-01

The model of GaAs1- y N y ( y = 0.001) as a heavily-doped semiconductor in the ultra-dilute region is attentively examined. The model enables GaAsN to be viewed as a disordered assembly of three-dimensional quantum dots (potential wells) caused by random potential fluctuations from nitrogen pairs in the system. Consequently, Feynman's path-integration technique is applied in order to quantify the density of states (DOS) in the vicinity of the conduction band edge. The obtained DOS tail, even though overestimated, still clearly shows a much shorter tail than that the experimental result does. This shows that the heavily-doped semiconductor viewpoint is not proper for GaAsN, not even in the ultra-dilute region. Furthermore, this also suggests that the impurity wave function overlap is not a basic mechanism of band gap reduction.

China's move to food irradiation

International Nuclear Information System (INIS)

Wedekind, L.H.

1986-01-01

The Chinese officials outlined China's past and future directions at a recent international food irradiation seminar in Shanghai sponsored by the FAO and IAEA. The meeting was attended by about 170 participants from China and 22 other countries, primarily from the Asian and Pacific region. Three food irradiation plants currently are operating in the region and 14 more are planned over the next 5 years. It was reported that China continues to suffer high food losses, up to 30% for some commodities, primarily due to preservation and storage problems. In January 1986, the first of five regional irradiation facilities planned in China officially opened in Shanghai. The Shanghai irradiation centre plans to process up to 35,000 tons of vegetables a year, as well as some spices, fruits, and non-food products. The Ministry of Public Health has approved seven irradiated foods as safe human diets: rice, potatoes, onions, garlic, peanuts, mushrooms and pork sausages; approval for apples is expected shortly. The Chinese officials at the Shanghai meeting stressed their openness to foreign participation and cooperation in food irradiation's development

Food preservation by irradiation

International Nuclear Information System (INIS)

Gottschalk, M.

1978-01-01

In November, 1977, an International Symposium on Food Preservation by Irradiation was held at Wageningen, the Netherlands. About 200 participants attended the Symposium which was organised by the International Atomic Energy Agency, the Food and Agriculture Organization of the United Nations and the World Health Organization; a reflection of the active interest which is being shown in food irradiation processing, particularly among developing countries. The 75 papers presented provided an excellent review of the current status of food irradiation on a wide range of different topics, and the Symposium also afforded the valuable opportunity for informal discussion among the participants and for developing personal contacts. A brief survey of the salient aspects discussed during the course of the meeting are reported on. (orig.) [de

Food irradiation in the United States

International Nuclear Information System (INIS)

Pauli, G.H.

1991-01-01

Since 1963, some irradiated foods have been permitted for sale in the United States. Yet, at this time, commercial application has been limited to irradiation of a relatively small fraction of the spices and seasonings used as ingredients in other foods. The current situation regarding irradiated foods in the United States and how it developed is discussed. The author writes from experience gained as a Government regulator concerned primarily with ensuring safety of food and therefore this is stressed together with the crucial role played by consumers and industry. (author)

NSUF Irradiated Materials Library

Energy Technology Data Exchange (ETDEWEB)

Cole, James Irvin [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2015-09-01

The Nuclear Science User Facilities has been in the process of establishing an innovative Irradiated Materials Library concept for maximizing the value of previous and on-going materials and nuclear fuels irradiation test campaigns, including utilization of real-world components retrieved from current and decommissioned reactors. When the ATR national scientific user facility was established in 2007 one of the goals of the program was to establish a library of irradiated samples for users to access and conduct research through competitively reviewed proposal process. As part of the initial effort, staff at the user facility identified legacy materials from previous programs that are still being stored in laboratories and hot-cell facilities at the INL. In addition other materials of interest were identified that are being stored outside the INL that the current owners have volunteered to enter into the library. Finally, over the course of the last several years, the ATR NSUF has irradiated more than 3500 specimens as part of NSUF competitively awarded research projects. The Logistics of managing this large inventory of highly radioactive poses unique challenges. This document will describe materials in the library, outline the policy for accessing these materials and put forth a strategy for making new additions to the library as well as establishing guidelines for minimum pedigree needed to be included in the library to limit the amount of material stored indefinitely without identified value.

Societal benefits of food irradiation

International Nuclear Information System (INIS)

Prakash, Anuradha

2013-01-01

Food irradiation has a direct impact on society by reducing the occurrence of food-borne illness, decreasing food spoilage and waste, and facilitating global trade. Food irradiation is approved in 40 countries around the world to decontaminate food of disease and spoilage causing microorganisms, sterilize insect pests, and inhibit sprouting. A recent estimate suggests that 500,000 metric of food is currently irradiated worldwide, primarily to decontaminate spices. Since its first use in the 1960s the use of irradiation for food has grown slowly, but it remains the major technology of choice for certain applications. The largest growth sector in recent years has been phytosanitary irradiation of fruit to disinfest fruit intended for international shipment. For many countries which have established strict quarantine standards, irradiation offers as an effective alternative to chemical fumigants some of which are being phased out due to their effects on the ozone layer. Insects can be sterilized at very low dose levels, thus quality of fruit can be maintained. Irradiation is also highly effective in destroying microbial pathogens such as Salmonella spp., E. coli, and Listeria, hence its application for treatment of spices, herbs, dried vegetables, frozen seafood, poultry, and meat and its contribution to reducing foodborne illnesses. Unfortunately the use of irradiation for improving food safety has been under-exploited. This presentation will provide details on the use, benefits, opportunities, and challenges of food irradiation. (author)

Signal development in irradiated silicon detectors

CERN Document Server

Kramberger, Gregor; Mikuz, Marko

2001-01-01

This work provides a detailed study of signal formation in silicon detectors, with the emphasis on detectors with high concentration of irradiation induced defects in the lattice. These defects give rise to deep energy levels in the band gap. As a consequence, the current induced by charge motion in silicon detectors is signifcantly altered. Within the framework of the study a new experimental method, Charge correction method, based on transient current technique (TCT) was proposed for determination of effective electron and hole trapping times in irradiated silicon detectors. Effective carrier trapping times were determined in numerous silicon pad detectors irradiated with neutrons, pions and protons. Studied detectors were fabricated on oxygenated and non-oxygenated silicon wafers with different bulk resistivities. Measured effective carrier trapping times were found to be inversely proportional to fuence and increase with temperature. No dependence on silicon resistivity and oxygen concentration was observ...

An X-ray wave theory for heavily distorted crystals. 1

International Nuclear Information System (INIS)

Ohkawa, T.; Hashimoto, H.

1985-01-01

An X-ray diffraction theory is developed of monochromatic waves having spherical wave front, which is applicable to an interpretation of divergent X-ray diffraction images of crystals containing arbitral types of strain field. The theory is divided into two parts. In part I, Takagi's theory is expanded by introducing amplitude and phase correction functions and a new improved representation for the X-ray diffraction theory is given. In part II dispersion surfaces in heavily distorted crystals are discussed, and in the discussion the resonance shift functions are introduced. These formulations can lead to a complete understanding of the extinction phenomena. (author)

Coupling UV irradiation and electrocoagulation for reclamation of urban wastewater

International Nuclear Information System (INIS)

Cotillas, Salvador; Llanos, Javier; Miranda, Oscar G.; Díaz-Trujillo, Gerardo C.; Cañizares, Pablo; Rodrigo, Manuel A.

2014-01-01

Graphical abstract: - Highlights: • Iron electrodes allow removing turbidity and E. coli in urban wastewaters. • Enmeshment into growing flocs and oxidation are the key disinfection processes. • A synergistic effect of coupling UV and EC is found at low current densities. • Efficiency of UV irradiation is lowered at high current density. - Abstract: This work focuses on coupling electrocoagulation, with iron electrodes, and UV irradiation (photo-electrocoagulation) for the simultaneous removal of turbidity and E. coli from actual treated municipal wastewaters. Results show that single electrocoagulation behaves as a very efficient technology even using low current densities. E. coli is removed not only by the enmeshment of microorganisms into growing flocs, but also by the attack of electrochemically produced chlorine disinfectant species. Coupling UV irradiation to electrocoagulation with iron electrodes improves the process performance in terms of E. coli and turbidity removal. The effect of current density on process performance was evaluated, finding a synergistic interaction of both techniques at low current density (1.44 A m −2 ) but an antagonistic effect at higher values of current density (7.20 A m −2 ). This antagonistic effect is caused by the less efficient transmission of UV irradiation to the bulk solution due to the increase in the concentration of solids

Chronic radiation exposure as an ecological factor: Hypermethylation and genetic differentiation in irradiated Scots pine populations

International Nuclear Information System (INIS)

Volkova, P.Yu.; Geras'kin, S.A.; Horemans, N.; Makarenko, E.S.; Saenen, E.; Duarte, G.T.; Nauts, R.; Bondarenko, V.S.; Jacobs, G.; Voorspoels, S.; Kudin, M.

2018-01-01

Genetic and epigenetic changes were investigated in chronically irradiated Scots pine (Pinus sylvestris L.) populations from territories that were heavily contaminated by radionuclides as result of the Chernobyl Nuclear Power Plant accident. In comparison to the reference site, the genetic diversity revealed by electrophoretic mobility of AFLPs was found to be significantly higher at the radioactively contaminated areas. In addition, the genome of pine trees was significantly hypermethylated at 4 of the 7 affected sites. - Highlights: • Chronic radiation exposure changes the genetic structure of plant populations. • Genomes of irradiated pines are hypermethylated. • The level of hypermethylation does not depend on annual dose. - These results indicate that even relatively low levels of chronic radiation exposure can influence on the genetic characteristics and the methylation status of natural pine populations and that it should be considered as an important ecological factor reflecting the anthropogenic impact on ecosystems.

Consumer acceptance of irradiated poultry

International Nuclear Information System (INIS)

Hashim, I.B.; Resurreccion, A.V.A.; McWatters, K.H.

1995-01-01

A simulated supermarket setting (SSS) test was conducted to determine whether consumers (n = 126) would purchase irradiated poultry products, and the effects of marketing strategies on consumer purchase of irradiated poultry products. Consumer preference for irradiated poultry was likewise determined using a home-use test. A slide program was the most effective educational strategy in changing consumers' purchase behavior. The number of participants who purchased irradiated boneless, skinless breasts and irradiated thighs after the educational program increased significantly from 59.5 and 61.9% to 83.3 and 85.7% for the breasts and thighs, respectively. Using a label or poster did not increase the number of participants who bought irradiated poultry products. About 84% of the participants consider it either 'somewhat necessary' or 'very necessary' to irradiate raw chicken and would like all chicken that was served in restaurants or fast food places to be irradiated. Fifty-eight percent of the participants would always buy irradiated chicken if available, and an additional 27% would buy it sometimes. About 44% of the participants were willing to pay the same price for irradiated chicken as for nonirradiated. About 42% of participants were willing to pay 5% or more than what they were currently paying for nonirradiated chicken. Seventy-three percent or more of consumers who participated in the home-use test (n = 74) gave the color, appearance, and aroma of the raw poultry products a minimum rating of 7 (= like moderately). After consumers participated in a home-use test, 84 and 88% selected irradiated thighs and breasts, respectively, over nonirradiated in a second SSS test

Consumer acceptance of irradiated poultry.

Science.gov (United States)

Hashim, I B; Resurreccion, A V; McWatters, K H

1995-08-01

A simulated supermarket setting (SSS) test was conducted to determine whether consumers (n = 126) would purchase irradiated poultry products, and the effects of marketing strategies on consumer purchase of irradiated poultry products. Consumer preference for irradiated poultry was likewise determined using a home-use test. A slide program was the most effective educational strategy in changing consumers' purchase behavior. The number of participants who purchased irradiated boneless, skinless breasts and irradiated thighs after the educational program increased significantly from 59.5 and 61.9% to 83.3 and 85.7% for the breasts and thighs, respectively. Using a label or poster did not increase the number of participants who bought irradiated poultry products. About 84% of the participants consider it either "somewhat necessary" or "very necessary" to irradiate raw chicken and would like all chicken that was served in restaurants or fast food places to be irradiated. Fifty-eight percent of the participants would always buy irradiated chicken if available, and an additional 27% would buy it sometimes. About 44% of the participants were willing to pay the same price for irradiated chicken as for nonirradiated. About 42% of participants were willing to pay 5% or more than what they were currently paying for nonirradiated chicken. Seventy-three percent or more of consumers who participated in the home-use test (n = 74) gave the color, appearance, and aroma of the raw poultry products a minimum rating of 7 (= like moderately). After consumers participated in a home-use test, 84 and 88% selected irradiated thighs and breasts, respectively, over nonirradiated in a second SSS test.

The growth of intra-granular bubbles in post-irradiation annealed UO2 fuel

International Nuclear Information System (INIS)

White, R.J.

2001-01-01

Post-irradiation examinations of low temperature irradiated UO 2 reveal large numbers of very small intra-granular bubbles, typically of around 1 nm diameter. During high temperature reactor transients these bubbles act as sinks for fission gas atoms and vacancies and can give rise to large volumetric swellings, sometimes of the order of 10%. Under irradiation conditions, the nucleation and growth of these bubbles is determined by a balance between irradiation-induced nucleation, diffusional growth and an irradiation induced re-solution mechanism. This conceptual picture is, however, incomplete because in the absence of irradiation the model predicts that the bubble population present from the pre-irradiation would act as the dominant sink for fission gas atoms resulting in large intra-granular swellings and little or no fission gas release. In practice, large fission gas releases are observed from post-irradiation annealed fuel. A recent series of experiments addressed the issue of fission gas release and swelling in post-irradiation annealed UO 2 originating from Advanced Gas Cooled Reactor (AGR) fuel which had been ramp tested in the Halden Test reactor. Specimens of fuel were subjected to transient heating at ramp rates of 0.5 deg. C/s and 20 deg. C/s to target temperatures between 1600 deg. C and 1900 deg. C. The release of fission gas was monitored during the tests. Subsequently, the fuel was subjected to post-irradiation examination involving detailed Scanning Electron Microscopy (SEM) analysis. Bubble-size distributions were obtained from seventeen specimens, which entailed the measurement of nearly 26,000 intra-granular bubbles. The analysis reveals that the bubble densities remain approximately invariant during the anneals and the bubble-size distributions exhibit long exponential tails in which the largest bubbles are present in concentrations of 10 4 or 10 5 lower than the concentrations of the average sized bubbles. Detailed modelling of the bubble

Temperature impact on the micro structure of tungsten exposed to He irradiation in LHD

International Nuclear Information System (INIS)

Bernard, Elodie; Sakamoto, Ryuichi; Tokitani, Masayuki; Masuzaki, Suguru; Hayashi, Hiromi; Yamada, Hiroshi; Yoshida, Naoaki

2017-01-01

A new temperature controlled material probe was designed for the exposure of tungsten samples to helium plasma in the LHD. Samples were exposed to estimated fluences of ∼10 23  m −2 and temperatures ranging from 65 to 600 °C. Transmission Electron Microscopy analysis allowed the study of the impact of He irradiation under high temperatures on tungsten micro structure for the first time in real-plasma exposure conditions. Both dislocation loops and bubbles appeared from low to medium temperatures and saw an impressive increase of size (factor 4 to 6) most probably by coalescence as the temperature reaches 600 °C, with 500 °C appearing as a threshold for bubble growth. Annealing of the samples up to 800 C highlighted the stability of the dislocation damages formed by helium irradiation at high surface temperature, as bubbles and dislocation loops seem to conserve their characteristics. Additional studies on cross-sections showed that bubbles were formed much deeper (70–100 nm) than the heavily damaged surface layer (10–20 nm), raising concern about the impact on the material mechanical properties conservation and potential additional trapping of hydrogen isotopes. - Highlights: • Design and test of a temperature-controlled sample holder to expose samples in LHD. • Dislocation loops and bubbles created in W even at low fluences and temperatures. • Heavily damaged layer (10–20 nm thick) very rich in damages formed at the surface. • He bubbles observed much deeper than implantation range (until 100 nm). • He effects not only at the surface, raising concerns for properties conservation.

Effects of 3.1-MeV proton and 1-GeV Au-ion irradiation on the magnetic flux noise and critical current of YBa2Cu3O7-δ

International Nuclear Information System (INIS)

Shaw, T.J.; Clarke, J.; van Dover, R.B.; Schneemeyer, L.F.; White, A.E.

1996-01-01

We have used a dc superconducting quantum interference device to measure the spectral density of magnetic flux noise, S Φ (f), generated by vortex motion in crystals of YBa 2 Cu 3 O 7-δ (YBCO) both before and after irradiation with 3.1-MeV protons and 1-GeV Au ions. In addition, we have studied the effects of irradiation on the critical current J c of the same samples. Both types of irradiation reduced S Φ (f) at most temperatures and magnetic fields and increased J c at all temperatures and magnetic fields. By measuring S Φ (f) versus temperature, we extract the distribution of vortex pinning energies, D(U 0 ). Both crystals have peaks in D(U 0 ) near 0.1 eV and 0.2 eV before irradiation, and a much reduced peak near 0.1 eV after irradiation. The noise level after either kind of irradiation was substantially higher than in an unirradiated YBCO film. copyright 1996 The American Physical Society

Food irradiation and packaging

International Nuclear Information System (INIS)

Kilcast, David

1988-01-01

This outline review was written for 'Food Manufacture'. It deals with the known effects of irradiation on current packaging materials (glass, cellulosics, organic polymers and metals), and their implications for the effective application of the process. (U.K.)

Deficient repair and degradation of DNA in X-irradiated L5178Y S/S cells: cell-cycle and temperature dependence

International Nuclear Information System (INIS)

Ueno, A.M.; Goldin, E.M.; Cox, A.B.; Lett, J.T.

1979-01-01

The rejoining of DNA strand breaks induced by X rays in the radiosensitive S/S variant of the L5178Y murine leukemic lymphoblast has been studied by alkaline-EDTA-sucrose sedimentation using swinging-bucket and zonal rotors. After irradiation, incubation resulted in an increase in DNA size, but the DNA structures were not restored in all cells, even when the x-ray dose was only 50 rad. Subsequently, 10 to 20 h after irradiation, heavily degraded DNA began to appear. When cells were irradiated at different parts of the cycle, the extent of DNA degradation varied in a fashion similar to survival: Least DNA degradation was found after irradiation at the most radioresistant stage (G 1 + 8 h), and most DNA degradation occurred after irradiation at the radiosensitive stage (G 1 ). Changes in cell survival caused by postirradiation hypothermia were also reflected in the extent of DNA degradation. Populations of G 1 cells, which show marked increases in survival after postirradiation hypothermic exposure, exhibited a lower level of DNA degradation, whereas populations of G 1 + 8 h cells, whose survival is affected little by postirradiation hypothermia, showed limited changes in DNA degradation. The onset of degradation was delayed by hypothermia in all cases

Effect of interaction between irradiation-induced defects and intrinsic defects in the pinning improvement of neutron irradiated YBaCuO sample

International Nuclear Information System (INIS)

Topal, Ugur; Sozeri, Huseyin; Yavuz, Hasbi

2004-01-01

Interaction between the intrinsic (native) defects and the irradiation-induced defects created by neutron irradiation was examined for the YBCO sample. For this purpose, non-superconducting Y-211 phase was included to the Y-123 samples at different contents as a source of large pinning center. The critical current density enhancement with the irradiation for these samples were analysed and then the role of defects on pinning improvement was discussed

Effect of interaction between irradiation-induced defects and intrinsic defects in the pinning improvement of neutron irradiated YBaCuO sample

Energy Technology Data Exchange (ETDEWEB)

Topal, Ugur; Sozeri, Huseyin; Yavuz, Hasbi

2004-08-01

Interaction between the intrinsic (native) defects and the irradiation-induced defects created by neutron irradiation was examined for the YBCO sample. For this purpose, non-superconducting Y-211 phase was included to the Y-123 samples at different contents as a source of large pinning center. The critical current density enhancement with the irradiation for these samples were analysed and then the role of defects on pinning improvement was discussed.

Biological studies using mammalian cell lines and the current status of the microbeam irradiation system, SPICE

Energy Technology Data Exchange (ETDEWEB)

Konishi, T. [Dept. of Technical Support and Development, Fundamental Technology Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan)], E-mail: tkonishi@nirs.go.jp; Ishikawa, T. [Dept. of Technical Support and Development, Fundamental Technology Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Iso, H. [Dept. of Technical Support and Development, Fundamental Technology Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Neos-Tech Co. Ltd., Benten 4-11-13-202, Chuo-ku, Chiba 206-0045 (Japan); Yasuda, N.; Oikawa, M. [Dept. of Technical Support and Development, Fundamental Technology Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Higuchi, Y. [Dept. of Technical Support and Development, Fundamental Technology Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Neos-Tech Co. Ltd., Benten 4-11-13-202, Chuo-ku, Chiba 206-0045 (Japan); Kato, T. [Dept. of Technical Support and Development, Fundamental Technology Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Graduate School of Science, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshimaku, Tokyo 171-8501 (Japan); Hafer, K. [Department of Radiation Oncology, UCLA School of Medicine, Los Angeles, CA (United States); Kodama, K. [Dept. of Technical Support and Development, Fundamental Technology Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Neos-Tech Co. Ltd., Benten 4-11-13-202, Chuo-ku, Chiba 206-0045 (Japan); Hamano, T.; Suya, N.; Imaseki, H. [Dept. of Technical Support and Development, Fundamental Technology Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan)

2009-06-15

The development of SPICE (single-particle irradiation system to cell), a microbeam irradiation system, has been completed at the National Institute of Radiological Sciences (NIRS). The beam size has been improved to approximately 5 {mu}m in diameter, and the cell targeting system can irradiate up to 400-500 cells per minute. Two cell dishes have been specially designed: one a Si{sub 3}N{sub 4} plate (2.5 mm x 2.5 mm area with 1 {mu}m thickness) supported by a 7.5 mm x 7.5 mm frame of 200 {mu}m thickness, and the other a Mylar film stretched by pressing with a metal ring. Both dish types may be placed on a voice coil stage equipped on the cell targeting system, which includes a fluorescent microscope and a CCD camera for capturing cell images. This microscope system captures images of dyed cell nuclei, computes the location coordinates of individual cells, and synchronizes this with the voice coil motor stage and single-particle irradiation system consisting of a scintillation counter and a beam deflector. Irradiation of selected cells with a programmable number of protons is now automatable. We employed the simultaneous detection method for visualizing the position of mammalian cells and proton traversal through CR-39 to determine whether the targeted cells are actually irradiated. An immuno-assay was also performed against {gamma}-H2AX, to confirm the induction of DNA double-strand breaks in the target cells.

Food irradiation; Global aspects and future prospects

Energy Technology Data Exchange (ETDEWEB)

Matsuyama, Akira (Tokyo Univ. of Agriculture (Japan). Nodai Research Institute)

1990-07-01

This paper reviews researches, commentaries, and conference and public records of food irradiation, published mainly during the period 1987-1989, focusing on the current conditions of food irradiation that may pose not only scientific or technologic problems but also political issues or consumerism. Approximately 50 kinds of food, although not enough to fill economic benefit, are now permitted for food irradiation in the world. Consumerism is pointed out as the major factor that precludes the feasibility of food irradiation in the world. In the United States, irradiation is feasible only for spices. Food irradiation has already been feasible in France, Hollands, Belgium, and the Soviet Union; has under consideration in the Great Britain, and has been rejected in the West Germany. Although the feasibility of food irradiation is projected to increase gradually in the future, commercial success or failure depends on the final selection of consumers. In this respect, the role of education and public information are stressed. Meat radicidation and recent progress in the method for detecting irradiated food are referred to. (N.K.) 128 refs.

Comparative study of thermoluminescence detection methods for irradiated spices

International Nuclear Information System (INIS)

Kawamura, Y.; Kojima, K.; Sugita, T.; Yamada, T.; Saito, Y.

1995-01-01

The thermoluminescence (TL) detection methods for irradiated spices were compared using spice samples obtained on the Japanese market, irradiated at doses of 1, 5, 10 and 30 kGy and stored for 1 year before analysis. The TL intensities of irradiated spices were stable for 1 year after irradiation. Measurement with whole samples failed to identify irradiated samples. Minerals were separated from spices in sodium tungstate saturated solution and/or sodium polytungstate solution. The TL intensity of minerals which had undergone irradiation was significantly increased for all samples. However, the ranges of TL intensity of irradiated and unirradiated samples overlapped. Clear discrimination has been obtained between the TL ratios of irradiated and unirradiated spices by using normalized measurement with reirradiation. The detection limit in terms of irradiation dose is 1 kGy even in a sample that has been irradiated 1 year prior to analysis. Normalization is the best technique currently available for thermoluminescence analysis to identify irradiated spices

Gamma irradiators for radiation processing

International Nuclear Information System (INIS)

2006-01-01

Radiation technology is one of the most important fields which the IAEA supports and promotes, and has several programmes that facilitate its use in the developing Member States. In view of this mandate, this Booklet on 'Gamma Irradiators for Radiation Processing' is prepared which describes variety of gamma irradiators that can be used for radiation processing applications. It is intended to present description of general principles of design and operation of the gamma irradiators available currently for industrial use. It aims at providing information to industrial end users to familiarise them with the technology, with the hope that the information contained here would assist them in selecting the most optimum irradiator for their needs. Correct selection affects not only the ease of operation but also yields higher efficiency, and thus improved economy. The Booklet is also intended for promoting radiation processing in general to governments and general public

Proceedings of 2005 JAEA-KAERI joint seminar on advanced irradiation and PIE technologies

International Nuclear Information System (INIS)

2006-05-01

In this seminar, total participants of over 100 were jointed from JAEA, KAERI, Hanyang University, Chungnam National University, Kyung Hee University, Oarai Branch of Institute for Materials Research (IMR) of Tohoku University, Nippon Nuclear Fuel Development Co., Ltd., Nuclear Development Corporation and others. The technical development and experimental data on the irradiation test and PIE were aggressively discussed in this seminar. Contributed presentations were 35 in three sessions; Current status and future program on irradiation test and PIE (10 presentations), Development of irradiation and PIE technologies (15 presentations) and Evaluation of irradiation and PIE data (10 presentations). Development of instrumented capsule technologies for HANARO irradiation, current PIE activities in each hot laboratory of both countries, development of irradiation capsules in JMTR for the Irradiation Assisted Stress Corrosion Cracking (IASCC) study, development of irradiation and PIE techniques for the safety research on the high burnup fuel, utilization plan of JOYO and development of MOX fuel containing americium have been widely noticed as topic items on irradiation and PIE technologies. This proceedings is containing papers presented in the 2005 JAEA-KAERI Joint Seminar. It also indicates the current status of the aggressive information exchange activity on two fields of irradiation test and PIE technologies between JAEA and KAERI under the Arrangement for the Implementation of Cooperative Research Program mentioned above. The 35 of the presented papers are indexed individually. (J.P.N.)

Effect of gamma irradiation on drugs

International Nuclear Information System (INIS)

Crucq, A.S.; Deridder, V.; Engalytcheff, A.; Slegers, C.; Tilquin, P.

2005-01-01

Several drugs (ceftazidime, vancomycin, glucagon, erythromycin and dobutamine) were studied in order to determine their radiostability. The methods used to measure the degradation of the drug were the potency and the colour change after irradiation. Electron spin resonance (ESR) is currently being used to detect irradiated foodstuffs and may be a promising technique to detect irradiated drugs. Trapped radicals in cefazolin sodium were studied and quantified by ESR for this purpose. It is proposed that the trapped radicals play an important role in the formation of the final radiolytic compounds. The potency of ceftazidime was not significantly modified after an irradiation of 25 kGy, whereas the potency of erythromycin and dobutamine decreased slightly. Glucagon was revealed to be radiosensitive with a significant decrease in its potency after irradiation. The visible spectra of glucagon and dobutamine did not change significantly after irradiation. The absorbance of erythromycin and vancomycin increased after irradiation. According to European Pharmacopoeia standards, the colour change of ceftazidime is unacceptable. The ESR spectra reveal that the trapped radicals in cefazolin sodium are characteristic of an irradiation. The radical concentration is dependent on the irradiation dose and decays over time. Radical concentration in cefazolin sodium was reduced by 99% after 100 days of storage. These radicals are responsible for about 13% of the measured final radiolytic product. Ionic reactions could also lead to final radiolytic products. (author)

Calculations of the displacement damage and short-circuit current degradation in proton irradiated (AlGa)As-GaAs solar cells

Science.gov (United States)

Yeh, C. S.; Li, S. S.; Loo, R. Y.

1987-01-01

A theoretical model for computing the displacement damage defect density and the short-circuit current (I sub sc) degradation in proton-irradiated (AlGa)As-GaAs p-n junction solar cells is presented. Assumptions were made with justification that the radiation induced displacement defects form an effective recombination center which controls the electron and hole lifetimes in the junction space charge region and in the n-GaAs active layer of the irradiated GaAs p-n junction cells. The degradation of I sub sc in the (AlGa)As layer was found to be negligible compared to the total degradation. In order to determine the I sub sc degradation, the displacement defect density, path length, range, reduced energy after penetrating a distance x, and the average number of displacements formed by one proton scattering event were first calculated. The I sub sc degradation was calculated by using the electron capture cross section in the p-diffused layer and the hole capture cross section in the n-base layer as well as the wavelength dependent absorption coefficients. Excellent agreement was found between the researchers calculated values and the measured I sub sc in the proton irradiated GaAs solar cells for proton energies of 100 KeV to 10 MeV and fluences from 10 to the 10th power p/square cm to 10 to the 12th power p/square cm.

Dual Inhibition of EGFR and VEGF in Heavily Pretreated Patients with Metastatic Colorectal Cancer

DEFF Research Database (Denmark)

Larsen, Finn Ole; Markussen, Alice; Nielsen, Dorte

2017-01-01

: The combination of irinotecan, bevacizumab, and cetuximab/panitumumab is safe and shows a toxicity profile corresponding to what is expected from the agents alone. The results indicate that the combination in the 4th line may result in a high rate of disease control in heavily pretreated patients with metastatic...

Analytical detection methods for irradiated foods

International Nuclear Information System (INIS)

1991-03-01

The present publication is a review of scientific literature on the analytical identification of foods treated with ionizing radiation and the quantitative determination of absorbed dose of radiation. Because of the extremely low level of chemical changes resulting from irradiation or because of the lack of specificity to irradiation of any chemical changes, a few methods of quantitative determination of absorbed dose have shown promise until now. On the other hand, the present review has identified several possible methods, which could be used, following further research and testing, for the identification of irradiated foods. An IAEA Co-ordinated Research Programme on Analytical Detection Methods for Irradiation Treatment of Food ('ADMIT'), established in 1990, is currently investigating many of the methods cited in the present document. Refs and tab

A New Approach on Output Current Calculation for Thimble-type Ionization Chamber with Variation of Gamma-ray Irradiation Angle

International Nuclear Information System (INIS)

Kim, Jae Cheon; Kim, Soon Young; Kim, Yong Kyun; Kim, Jong Kyung

2006-01-01

The output current of an ionization chamber is directly connected with the size of the active volume and ion-pair distribution in air volume. Their accurate assessments are significantly important in order to analyze the design characteristics of an ionization chamber and interpret the measurements with it. It has been generally assumed that ion-pairs are generated uniformly in air volume for simplicity although they are not uniformly distributed due to various source and geometry conditions. Ion-pair distribution is mainly dependent on the irradiation source conditions, while active volume is deeply related to the ionization chamber design. Therefore, such assumption should be examined if the ion-pair distribution affects real output current of the active volume defined by electric field. A new analytical approach considering both electric field and ion-pair nonuniformity has been proposed to analyze accurately the design characteristics of an ionization chamber and interpretation of measurements with it. The angular dependence analysis was carried out to validate the new concept for calculation of output current

Irradiation creep and swelling of various austenitic alloys irradiated in PFR and FFTF

Energy Technology Data Exchange (ETDEWEB)

Garner, F.A.; Toloczko, M.B. [Pacific Northwest National Lab., Richland, WA (United States)] [and others

1996-10-01

In order to use data from surrogate neutron spectra for fusion applications, it is necessary to analyze the impact of environmental differences on property development. This is of particular importance in the study of irradiation creep and its interactions with void swelling, especially with respect to the difficulty of separation of creep strains from various non-creep strains. As part of an on-going creep data rescue and analysis effort, the current study focuses on comparative irradiations conducted on identical gas-pressurized tubes produced and constructed in the United States from austenitic steels (20% CW 316 and 20% CW D9), but irradiated in either the Prototype Fast Reactor (PFR) in the United Kingdom or the Fast Flux Test Facility in the United States. In PFR, Demountable Subassemblies (DMSA) serving as heat pipes were used without active temperature control. In FFTF the specimens were irradiated with active ({+-}{degrees}5C) temperature control. Whereas the FFTF irradiations involved a series of successive side-by-side irradiation, measurement and reinsertion of the same series of tubes, the PFR experiment utilized simultaneous irradiation at two axial positions in the heat pipe to achieve different fluences at different flux levels. The smaller size of the DMSA also necessitated a separation of the tubes at a given flux level into two groups (low-stress and high-stress) at slightly different axial positions, where the flux between the two groups varied {le}10%. Of particular interest in this study was the potential impact of the two types of separation on the derivation of creep coefficients.

Tensile and stress corrosion cracking properties of type 304 stainless steel irradiated to a very high dose

International Nuclear Information System (INIS)

Chung, H.M.; Strain, R.V.; Shack, W.J.

2001-01-01

Certain safety-related core internal structural components of light water reactors, usually fabricated from Type 304 or 316 austenitic stainless steels (SSs), accumulate very high levels of irradiation damage (20-100 displacement per atom or dpa) by the end of life. Our databases and mechanistic understanding of the degradation of such highly irradiated components, however, are not well established. A key question is the nature of irradiation-assisted intergranular cracking at very high doses, i.e. is it purely mechanical failure or is it stress-corrosion cracking? In this work, hot-cell tests and microstructural characterization were performed on Type 304 SS from the hexagonal fuel can of the decommissioned EBR-II reactor after irradiation to ∼50 dpa at ∼370 deg. C. Slow-strain-rate tensile tests were conducted at 289 degree sign C in air and in water at several levels of electrochemical potential (ECP), and microstructural characteristics were analyzed by scanning and transmission electron microscopies. The material deformed significantly by twinning and exhibited surprisingly high ductility in air, but was susceptible to severe intergranular stress corrosion cracking (IGSCC) at high ECP. Low levels of dissolved O and ECP were effective in suppressing the susceptibility of the heavily irradiated material to IGSCC, indicating that the stress corrosion process associated with irradiation-induced grain-boundary Cr depletion, rather than purely mechanical separation of grain boundaries, plays the dominant role. However, although IGSCC was suppressed, the material was susceptible to dislocation channeling at a low ECP, and this susceptibility led to a poor work-hardening capability and low ductility

Effects of irradiation on platelet function

International Nuclear Information System (INIS)

Rock, G.; Adams, G.A.; Labow, R.S.

1988-01-01

Current medical practice involves the irradiation of blood components, including platelet concentrates, before their administration to patients with severe immunosuppression. The authors studied the effect of irradiation on in vitro platelet function and the leaching of plasticizers from the bag, both immediately and after 5 days of storage. The platelet count, white cell count, pH, glucose, lactate, platelet aggregation and release reaction, and serotonin uptake were not altered by the irradiation of random-donor or apheresis units with 2000 rads carried out at 0 and 24 hours and 5 days after collection. The leaching of di(2-ethylhexyl)phthalate from the plastic bags followed by the conversion to mono(2-ethylhexyl)phthalate was not increased by irradiation. Therefore, it is possible to irradiate platelet concentrates on the day of collection and subsequently store them for at least 5 days while maintaining in vitro function. This procedure could have considerable benefit for blood banks involved in the provision of many platelet products

Validation of gamma irradiator controls for quality and regulatory compliance

International Nuclear Information System (INIS)

Harding, R.B.; Pinteric, F.J.A.

1995-01-01

Since 1978 the U.S. Food and Drug Administration (FDA) has had both the legal authority and the current good manufacturing practice (CGMP) regulations in progress to require irradiator owners who process medical devices to produce evidence of Irradiation Process Validation. One of the key components of Irradiation Process Validation is the validation of the irradiator controls. However it is only recently that FDA audits have focussed on this component of the process validation. (author)

Simulation model for electron irradiated IGZO thin film transistors

Science.gov (United States)

Dayananda, G. K.; Shantharama Rai, C.; Jayarama, A.; Kim, Hyun Jae

2018-02-01

An efficient drain current simulation model for the electron irradiation effect on the electrical parameters of amorphous In-Ga-Zn-O (IGZO) thin-film transistors is developed. The model is developed based on the specifications such as gate capacitance, channel length, channel width, flat band voltage etc. Electrical parameters of un-irradiated IGZO samples were simulated and compared with the experimental parameters and 1 kGy electron irradiated parameters. The effect of electron irradiation on the IGZO sample was analysed by developing a mathematical model.

One unit-cell seed layer induced epitaxial growth of heavily nitrogen doped anatase TiO{sub 2} films

Energy Technology Data Exchange (ETDEWEB)

Chen, T L; Hirose, Y; Hitosugi, T; Hasegawa, T [Kanagawa Academy of Science and Technology (KAST), Kawasaki 213-0012 (Japan)], E-mail: chen@ksp.or.jp

2008-03-21

We present a novel way to obtain heavily nitrogen doped anatase TiO{sub 2} films by using a solid-state nitrogen source. Epitaxial growth of the films was realized by introducing one unit-cell seed layer, which was indicated by reflection high-energy electron diffraction as intensity oscillation. Results of x-ray diffraction and x-ray photoelectron spectroscopy confirmed that the films were in the anatase phase heavily doped with nitrogen of {approx}15 at%. The films obtained exhibited considerable narrowing of the optical bandgap, resulting in an enhancement of absorption in the visible-light region. (fast track communication)

High-temperature ferromagnetism in heavily Fe-doped ferromagnetic semiconductor (Ga,Fe)Sb

International Nuclear Information System (INIS)

Tu, Nguyen Thanh; Hai, Pham Nam; Anh, Le Duc; Tanaka, Masaaki

2016-01-01

We show high-temperature ferromagnetism in heavily Fe-doped ferromagnetic semiconductor (Ga_1_−_x,Fe_x)Sb (x = 23% and 25%) thin films grown by low-temperature molecular beam epitaxy. Magnetic circular dichroism spectroscopy and anomalous Hall effect measurements indicate intrinsic ferromagnetism of these samples. The Curie temperature reaches 300 K and 340 K for x = 23% and 25%, respectively, which are the highest values reported so far in intrinsic III-V ferromagnetic semiconductors.

Insect disinfestation of pulses by irradiation

International Nuclear Information System (INIS)

Bhuiya, A.D.; Ahmed, M.; Rezaur, R.; Seal, D.R.; Nahar, G.; Islam, M.M.; Islam, M.S.

1985-01-01

Studies were carried out on four varieties of pulses, namely, mosur or lentil (Lens esculenta), mung (Phaseolus aureus), chola or gram (Cirecer aricitinum), and mashkalai (Phaseolus radiatus). Two major burchid betles, Callosobruchus chinensis (L.) and Callosobruchus analis (Fab.), were found to infest different varieties of pulses. Radiation sensitivity of the two pulse beetles was determined at different developmental stages (i.e., eggs, larvae, and pupae). Emergence of adults from eggs totally stopped at a dose of 0.04 kGy. Doses of 0.28 and 0.32 kGy, respectively, were required for complete inhibition of adult emergence from irradiated fourth instar larvae of C. analis and C. chinensis. Studies revealed that the experimental gram was heavily infested (65-91 percent) as compared to other pulses after 8 months of storage in all packaging materials used (gunny bag, gunny bag lined with polyethylene, polyethylene and polyvinyl chloride bags). Mashkalai showed insignificant damage (2-5 percent) by the insects. Reinfestation in the treated products was observed in polyethylene and gunny bags

Einstein's photoemission emission from heavily-doped quantized structures

CERN Document Server

Ghatak, Kamakhya Prasad

2015-01-01

This monograph solely investigates the Einstein's Photoemission(EP) from Heavily Doped(HD) Quantized Structures on the basis of newly formulated electron dispersion laws. The materials considered are quantized structures of HD non-linear optical, III-V, II-VI, Ge, Te, Platinum Antimonide, stressed materials, GaP, Gallium Antimonide, II-V, Bismuth Telluride together with various types of HD superlattices and their Quantized counterparts respectively. The EP in HD opto-electronic materials and their nanostructures is studied in the presence of strong light waves and intense electric fields  that control the studies of such quantum effect devices. The suggestions for the experimental determinations of different important physical quantities in HD 2D and 3D materials  and the importance of measurement of band gap in HD optoelectronic materials under intense built-in electric field in nano devices and strong external photo excitation (for measuring   physical properties in the presence of intense light waves w...

Radiation induced leakage current and stress induced leakage current in ultra-thin gate oxides

International Nuclear Information System (INIS)

Ceschia, M.; Paccagnella, A.; Cester, A.; Scarpa, A.

1998-01-01

Low-field leakage current has been measured in thin oxides after exposure to ionizing radiation. This Radiation Induced Leakage Current (RILC) can be described as an inelastic tunneling process mediated by neutral traps in the oxide, with an energy loss of about 1 eV. The neutral trap distribution is influenced by the oxide field applied during irradiation, thus indicating that the precursors of the neutral defects are charged, likely being defects associated to trapped holes. The maximum leakage current is found under zero-field condition during irradiation, and it rapidly decreases as the field is enhanced, due to a displacement of the defect distribution across the oxide towards the cathodic interface. The RILC kinetics are linear with the cumulative dose, in contrast with the power law found on electrically stressed devices

Irradiation-Accelerated Corrosion of Reactor Core Materials. Final Report

Energy Technology Data Exchange (ETDEWEB)

Jiao, Zhujie [Univ. of Michigan, Ann Arbor, MI (United States); Was, Gary [Univ. of Michigan, Ann Arbor, MI (United States); Bartels, David [Univ. of Notre Dame, IN (United States)

2015-04-02

This project aims to understand how radiation accelerates corrosion of reactor core materials. The combination of high temperature, chemically aggressive coolants, a high radiation flux and mechanical stress poses a major challenge for the life extension of current light water reactors, as well as the success of most all GenIV concepts. Of these four drivers, the combination of radiation and corrosion places the most severe demands on materials, for which an understanding of the fundamental science is simply absent. Only a few experiments have been conducted to understand how corrosion occurs under irradiation, yet the limited data indicates that the effect is large; irradiation causes order of magnitude increases in corrosion rates. Without a firm understanding of the mechanisms by which radiation and corrosion interact in film formation, growth, breakdown and repair, the extension of the current LWR fleet beyond 60 years and the success of advanced nuclear energy systems are questionable. The proposed work will address the process of irradiation-accelerated corrosion that is important to all current and advanced reactor designs, but remains very poorly understood. An improved understanding of the role of irradiation in the corrosion process will provide the community with the tools to develop predictive models for in-reactor corrosion, and to address specific, important forms of corrosion such as irradiation assisted stress corrosion cracking.

Treatment of skin damage due to irradiation and post-irradiation skin tumours, at the Hornheide special clinic

International Nuclear Information System (INIS)

Drepper, H.

1987-01-01

A short precis of 54 years of history of the Hornheide special clinic for tumours, tuberculosis, and plastic surgery of face and skin is followed by a description of the current tasks of the clinic as an interdisciplinary center for plastic surgery and rehabilitation with facilities for tumour surgery, radiotherapy, skin and tissue pathology, and psychotherapy. Important special areas of this interdisciplinary cooperation are the treatment of skin disorders due to radiation and of tumours on irradiated skin, as well as treatment and plastic surgery after removal of tumours by irradiation in order to make the affected areas fit for renewed irradiation. (TRV) [de

Flux effect on neutron irradiation embrittlement of reactor pressure vessel steels irradiated to high fluences

International Nuclear Information System (INIS)

Soneda, N.; Dohi, K.; Nishida, K.; Nomoto, A.; Iwasaki, M.; Tsuno, S.; Akiyama, T.; Watanabe, S.; Ohta, T.

2011-01-01

Neutron irradiation embrittlement of reactor pressure vessel (RPV) steels is of great concern for the long term operation of light water reactors. In particular, the embrittlement of the RPV steels of pressurized water reactors (PWRs) at very high fluences beyond 6*10 19 n/cm 2 , E > 1 MeV, needs to be understood in more depth because materials irradiated in material test reactors (MTRs) to such high fluences show larger shifts than predicted by current embrittlement correlation equations available worldwide. The primary difference between the irradiation conditions of MTRs and surveillance capsules is the neutron flux. The neutron flux of MTR is typically more than one order of magnitude higher than that of surveillance capsule, but it is not necessarily clear if this difference in neutron flux causes difference in mechanical properties of RPV. In this paper, we perform direct comparison, in terms of mechanical property and microstructure, between the materials irradiated in surveillance capsules and MTRs to clarify the effect of flux at very high fluences and fluxes. We irradiate the archive materials of some of the commercial reactors in Japan in the MTR, LVR-15, of NRI Rez, Czech Republic. Charpy impact test results of the MTR-irradiated materials are compared with the data from surveillance tests. The comparison of the results of microstructural analyses by means of atom probe tomography is also described to demonstrate the similarity / differences in surveillance and MTR-irradiated materials in terms of solute atom behavior. It appears that high Cu material irradiated in a MTR presents larger shifts than those of surveillance data, while low Cu materials present similar embrittlement. The microstructural changes caused by MTR irradiation and surveillance irradiation are clearly different

Long-Term Stability of Oxide Nanowire Sensors via Heavily Doped Oxide Contact.

Science.gov (United States)

Zeng, Hao; Takahashi, Tsunaki; Kanai, Masaki; Zhang, Guozhu; He, Yong; Nagashima, Kazuki; Yanagida, Takeshi

2017-12-22

Long-term stability of a chemical sensor is an essential quality for long-term collection of data related to exhaled breath, environmental air, and other sources in the Internet of things (IoT) era. Although an oxide nanowire sensor has shown great potential as a chemical sensor, the long-term stability of sensitivity has not been realized yet due to electrical degradation under harsh sensing conditions. Here, we report a rational concept to accomplish long-term electrical stability of metal oxide nanowire sensors via introduction of a heavily doped metal oxide contact layer. Antimony-doped SnO 2 (ATO) contacts on SnO 2 nanowires show much more stable and lower electrical contact resistance than conventional Ti contacts for high temperature (200 °C) conditions, which are required to operate chemical sensors. The stable and low contact resistance of ATO was confirmed for at least 1960 h under 200 °C in open air. This heavily doped oxide contact enables us to realize the long-term stability of SnO 2 nanowire sensors while maintaining the sensitivity for both NO 2 gas and light (photo) detections. The applicability of our method is confirmed for sensors on a flexible polyethylene naphthalate (PEN) substrate. Since the proposed fundamental concept can be applied to various oxide nanostructures, it will give a foundation for designing long-term stable oxide nanomaterial-based IoT sensors.

Various approaches in EPR identification of gamma-irradiated plant foodstuffs: A review.

Science.gov (United States)

Aleksieva, Katerina I; Yordanov, Nicola D

2018-03-01

Irradiation of food in the world is becoming a preferred method for their sterilization and extending their shelf life. For the purpose of trade with regard to the rights of consumers is necessary marking of irradiated foodstuffs, and the use of appropriate methods for unambiguous identification of radiation treatment. One-third of the current standards of the European Union to identify irradiated foods use the method of the Electron Paramagnetic Resonance (EPR) spectroscopy. On the other hand the current standards for irradiated foods of plant origin have some weaknesses that led to the development of new methodologies for the identification of irradiated food. New approaches for EPR identification of radiation treatment of herbs and spices when the specific signal is absent or disappeared after irradiation are discussed. Direct EPR measurements of dried fruits and vegetables and different pretreatments for fresh samples are reviewed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Self-Assembled Formation of Well-Aligned Cu-Te Nano-Rods on Heavily Cu-Doped ZnTe Thin Films

Science.gov (United States)

Liang, Jing; Cheng, Man Kit; Lai, Ying Hoi; Wei, Guanglu; Yang, Sean Derman; Wang, Gan; Ho, Sut Kam; Tam, Kam Weng; Sou, Iam Keong

2016-11-01

Cu doping of ZnTe, which is an important semiconductor for various optoelectronic applications, has been successfully achieved previously by several techniques. However, besides its electrical transport characteristics, other physical and chemical properties of heavily Cu-doped ZnTe have not been reported. We found an interesting self-assembled formation of crystalline well-aligned Cu-Te nano-rods near the surface of heavily Cu-doped ZnTe thin films grown via the molecular beam epitaxy technique. A phenomenological growth model is presented based on the observed crystallographic morphology and measured chemical composition of the nano-rods using various imaging and chemical analysis techniques. When substitutional doping reaches its limit, the extra Cu atoms favor an up-migration toward the surface, leading to a one-dimensional surface modulation and formation of Cu-Te nano-rods, which explain unusual observations on the reflection high energy electron diffraction patterns and apparent resistivity of these thin films. This study provides an insight into some unexpected chemical reactions involved in the heavily Cu-doped ZnTe thin films, which may be applied to other material systems that contain a dopant having strong reactivity with the host matrix.

High-temperature ferromagnetism in heavily Fe-doped ferromagnetic semiconductor (Ga,Fe)Sb

Energy Technology Data Exchange (ETDEWEB)

Tu, Nguyen Thanh [Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656 (Japan); Department of Physics, Ho Chi Minh City University of Pedagogy, 280, An Duong Vuong Street, District 5, Ho Chi Minh City 748242 (Viet Nam); Hai, Pham Nam [Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656 (Japan); Department of Physical Electronics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro, Tokyo 152-0033 (Japan); Center for Spintronics Research Network (CSRN), The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Anh, Le Duc [Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656 (Japan); Tanaka, Masaaki [Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656 (Japan); Center for Spintronics Research Network (CSRN), The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan)

2016-05-09

We show high-temperature ferromagnetism in heavily Fe-doped ferromagnetic semiconductor (Ga{sub 1−x},Fe{sub x})Sb (x = 23% and 25%) thin films grown by low-temperature molecular beam epitaxy. Magnetic circular dichroism spectroscopy and anomalous Hall effect measurements indicate intrinsic ferromagnetism of these samples. The Curie temperature reaches 300 K and 340 K for x = 23% and 25%, respectively, which are the highest values reported so far in intrinsic III-V ferromagnetic semiconductors.

Becoming a Heavily Tattooed Young Body: From a Bodily Experience to a Body Project

Science.gov (United States)

Ferreira, Vitor Sérgio

2014-01-01

Why some young people start to tattoo their bodies? And why some of them keep going on with this practice, until having all body tattooed? What doing so means to them? These are some of the questions that underlie a qualitative research project carried out in Portugal on heavily tattooed young people. In this article, the author discusses their…

Is phenytoin contraindicated in patients receiving cranial irradiation?

Energy Technology Data Exchange (ETDEWEB)

Borg, M.F. [Royal Adelaide Hospital, SA (Australia); Probert, J.C. [Auckland Hospital, Auckland (New Zealand). Dept. of Radiation Oncology; Zwi, L.J. [Auckland Univ. (New Zealand). Dept. of Medicine and Surgery

1995-02-01

Three recent publications have reported the development of erythema multiforme and Stevens-Johnson syndrome in patients receiving cranial irradiation and sodium phenytoin. Some authors have recommended that patients receiving whole brain radiation therapy and who have had seizures should not be prescribed phenytoin but an alternative anticonvulsant. This article reviews the current literature pertaining to the development of this potentially lethal complication in patients receiving whole brain radiation and phenytoin, with reference to the single recorded case of Stevens-Johnson syndrome in a patient receiving cranial irradiation and phenytoin in Auckland, New Zealand. While the clinical picture in the 16 patients reported in the literature and the current case report differed from the classical form of erythema multiforme, a similar pattern of presentation and outcome appeared in all patients reviewed, suggesting that the combination of phenytoin, cranial irradiation and the gradual reduction of concomitant steroids seem to lead to the development of erythema multiforme and/or Stevens-Johnson syndrome. The data presented, although sparse, suggest that phenytoin should not be prescribed in patients receiving cranial irradiation. 21 refs., 2 tabs., 3 figs.

Is phenytoin contraindicated in patients receiving cranial irradiation?

International Nuclear Information System (INIS)

Borg, M.F.; Probert, J.C.; Zwi, L.J.

1995-01-01

Three recent publications have reported the development of erythema multiforme and Stevens-Johnson syndrome in patients receiving cranial irradiation and sodium phenytoin. Some authors have recommended that patients receiving whole brain radiation therapy and who have had seizures should not be prescribed phenytoin but an alternative anticonvulsant. This article reviews the current literature pertaining to the development of this potentially lethal complication in patients receiving whole brain radiation and phenytoin, with reference to the single recorded case of Stevens-Johnson syndrome in a patient receiving cranial irradiation and phenytoin in Auckland, New Zealand. While the clinical picture in the 16 patients reported in the literature and the current case report differed from the classical form of erythema multiforme, a similar pattern of presentation and outcome appeared in all patients reviewed, suggesting that the combination of phenytoin, cranial irradiation and the gradual reduction of concomitant steroids seem to lead to the development of erythema multiforme and/or Stevens-Johnson syndrome. The data presented, although sparse, suggest that phenytoin should not be prescribed in patients receiving cranial irradiation. 21 refs., 2 tabs., 3 figs

Biodegradable foam trays obtained from mixtures of non-irradiated and irradiated cassava starches

International Nuclear Information System (INIS)

Brant, A.J.C.; Naime, N.; Lugao, A.B.; Ponce, P.

2015-01-01

Biodegradable polymers, such as starch, cellulose, PHB, PLA, and derivatives thereof, are being studied to produce innovative packaging in the most diverse shapes (films, bags, trays, bottles, etc.) to attend this current market trend. The aim of this work was to produce foam trays from cassava starch for food packaging by extrusion-thermopressing process. Their formulations were based on non-irradiated and γ-irradiated starches at diverse radiation absorbed doses (kGy) in order to evaluate the influence of the irradiated starches on the physical properties of the trays. Water absorption results showed an irregular increase with the increase of the absorbed dose: 26.32% and 39.84% for the trays based on starch 0 kGy and 1:1 (w/w) mixture of starches 0 kGy and 100.0 kGy, respectively. Other physicochemical properties were evaluated from the starches utilized and the trays obtained. (author)

Biodegradable foam trays obtained from mixtures of non-irradiated and irradiated cassava starches

Energy Technology Data Exchange (ETDEWEB)

Brant, A.J.C.; Naime, N.; Lugao, A.B.; Ponce, P., E-mail: thonybrant@gmail.com, E-mail: patiponce@gmail.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2015-07-01

Biodegradable polymers, such as starch, cellulose, PHB, PLA, and derivatives thereof, are being studied to produce innovative packaging in the most diverse shapes (films, bags, trays, bottles, etc.) to attend this current market trend. The aim of this work was to produce foam trays from cassava starch for food packaging by extrusion-thermopressing process. Their formulations were based on non-irradiated and γ-irradiated starches at diverse radiation absorbed doses (kGy) in order to evaluate the influence of the irradiated starches on the physical properties of the trays. Water absorption results showed an irregular increase with the increase of the absorbed dose: 26.32% and 39.84% for the trays based on starch 0 kGy and 1:1 (w/w) mixture of starches 0 kGy and 100.0 kGy, respectively. Other physicochemical properties were evaluated from the starches utilized and the trays obtained. (author)

Monitoring free radicals in γ-irradiated food

International Nuclear Information System (INIS)

Hunter, C.R.; Hutton, D.R.

1988-01-01

Irradiation of various food products, including vegetables, fruits, meats, seafoods, herbs, spices and seeds by appropriate doses by γ rays has for many years been suggested as a means of killing bacteria, viruses and pests and so preserving the foods. The position of food irradiation is under review in Australia through consumer organisations (Australian Consumers Association 1987) and by a current Federal Government inquiry. From these reviews and inquiries recommendations for irradiation, packaging, etc., are emerging, with for example, recommended maximum dose of 10 kGy for Australia, with 6 kGy being a minimum dose for grains and spices

Electron-irradiation-induced crystallization of amorphous orthophosphates

International Nuclear Information System (INIS)

Meldrum, A.; Ewing, R.C.; Boatner, L.A.

1996-12-01

Amorphous LaPO 4 , EuPO 4 , GdPO 4 , ScPO 4 , and fluorapatite [Ca 5 (PO 4 ) 3 F] were irradiated by electron beam in a TEM. Irradiations were done at -150 to 300 C, 80 to 200 keV, and current densities from 0.3 to 16 A/cm 2 . In all cases, the materials crystallized to form a randomly oriented polycrystalline assemblage. Crystallization is driven dominantly by inelastic processes, although ballistic collisions with target nuclei can be important above 175 keV, particularly in apatite. Using a high current density, crystallization is so fast that continuous lines of crystallites can be ''drawn'' on the amorphous matrix

Impact of irradiations by protons with different energies on silicon sensors

International Nuclear Information System (INIS)

Neubueser, Coralie

2013-06-01

In the frame of the CMS tracker upgrade campaign the radiation damage of oxygenrich n-type silicon pad diodes induced by 23 MeV and 23 GeV protons was investigated. The diodes were manufactured by Hamamatsu Photonics. After irradiation with 1 MeV neutron equivalent fluences between 1 x 10 11 cm -2 and 1.5 x 10 15 cm -2 , the sensors were electrically characterized by means of capacitance-voltage (CV) and current-voltage (IV) measurements. Current pulses recorded by the Transient Current Technique (TCT) and Charge Collection Efficiency (CCE) measurements show a dependence of the bulk damage on the proton energy. At a fluence of Φ eq ∼3 x 10 14 cm -2 oxygen-rich n-type diodes demonstrate clear Space Charge Sign Inversion (SCSI) after 23 MeV proton irradiation. This effect does not appear after the irradiation with 23 GeV protons. Moreover, RD50 pad diodes were irradiated with 23 MeV protons, electrically characterized and compared to results obtained after 23 GeV irradiations. Our previous observation on the energy dependence of the radiation damage could be confirmed. In order to get a deeper understanding of the differences of the radiation induced defects, the Deep Level Transient Spectroscopy (DLTS) and Thermally Stimulated Current Technique (TSC) were utilized. Defects with impact on the space charge could be identified and characterized and it was possible to find some hints for the reason of the SCSI after 23 MeV proton irradiation. Moreover, a dependence on the oxygen concentration of the sensors could be observed.

Detection of irradiation by thermo- and chemiluminescence

International Nuclear Information System (INIS)

Boegl, K.W.; Heide, Lydia

1991-01-01

In a number of countries it is not currently allowed to bring irradiated food into the market. On the other hand, increasing numbers of permits have been issued in many countries during the past years for the use of ionizing radiation in certain areas of food technology, because national and international bodies recommended food irradiation to be accepted. Therefore, the regulations concerning irradiated food will remain very different between individual countries during the coming years. This is the background for the increasing interest in developing methods that allow identification of irradiated food. During the past few years it has become increasingly clear that detailed labelling of irradiated food will need to be included in food regulations in many parts of the world. Identification methods will be helpful in proving compliance with these labelling regulations. Many investigations have been carried out in an effort to design reliable methods for detecting whether or not a food has been irradiated. Attempts have been to apply physical, chemical and biological forms of measurement. The results show that no general method exists that is applicable for all foods. For individual foodstuffs, several methods are possible, depending on the type of food, but none has as yet been internationally tested and accepted as reliable for all types of irradiated food. Two techniques are currently very close to practical application. On one side, the luminescence techniques have been tested in a European collaborative study with good results, so that these luminescence techniques have been included in the official collection of food control methods in the Federal Republic of Germany in 1989. On the other side, electron spin resonance spectroscopy has been demonstrated as well suited for detection purposes for different types of food containing bones, shells or seed, like chicken and strawberries. A European collaborative study is also in preparation. (author)

Radiation processing. Current status and future possibilities

International Nuclear Information System (INIS)

Woods, R.J.

2000-01-01

Radiation processing developed following the Second World War and employees gamma- or electron-irradiation to process polymers, cure alkene-based inks and coatings, sterilize medical supplies, irradiate food, and manage wastes. The current status of these applications is described with the probable direction of future developments. (author)

Doping of 6H-SiC pn structures by proton irradiation

International Nuclear Information System (INIS)

Strel'chuk, Anatoly M.; Lebedev, Alexandre A.; Kozlovski, Vitali V.; Savkina, Natali S.; Davydov, Denis V.; Solov'ev, Viktor V.; Rastegaeva, Marina G.

1999-01-01

The influence of proton irradiation on current-voltage characteristics, N d - N a values and parameters of deep centres in 6H-SiC pn structures grown by sublimation epitaxy has been studied. The irradiation was carried out with 8 MeV protons in the range of doses from 10 14 to 10 16 cm -2 . Irradiation with a dose of 3.6x10 14 cm -2 leaves the voltage drop at high forward currents (10 A/cm 2 ) practically unchanged. For higher irradiation dose of 1.8x10 15 cm -2 , the forward voltage drop and the degree of compensation in the samples increased ; partial annealing of the radiation defects and partial recovery of the electrical parameters occurred after annealing at T∼400-800 K. Irradiation with a dose of 5.4x10 15 cm -2 resulted in very high resistance in forward biased pn structures which remained high even after heating to 500 deg. C. It is suggested that proton irradiation causes decreasing of the lifetime and formation of an i- or an additional p-layer

Movement of beta-irradiated epidermal basal cells to the spinous-granular layers in the absence of cell division

International Nuclear Information System (INIS)

Etoh, H.; Taguchi, Y.H.; Tabachnick, J.

1975-01-01

Guinea-pig epidermis was irradiated with 3000 rad of beta rays 1 hr after two injections of [ 3 H]thymidine 5 hr apart (labeled cells in S phase and G 2 phase) or 18 hr after injection (labeled early G 1 cells). In nonirradiated epidermis labeled basal cells divided within 24 hr with daughter cells remaining in the basal layer, and approximately 50 percent of the labeled cells moved into the spinal layer by the 3rd day. Cell division in nonirradiated epidermis diluted the number of silver grains/nucleus, and lightly labeled cells were found in the granular layer by day 7. Beta irradiation inhibited cell division but it did not slow the rate of transit (ca 8 days) of irradiated labeled cells from basal to granular layer, some of these remaining heavily labeled. Although cell division may play some role in upward movement of basal cells in normal epidermis detachment of a basal cell from the basement membrane and its transit to the granular layer is unimpaired in the absence of cell division. These findings suggest that some radioresistant metabolic function(s), not cell division, is responsible for upward movement of basal cells. (auth)

Cytogenetic abnormalities of the descendants of permanent residents of heavily contaminated East Kazakhstan.

Science.gov (United States)

Chaizhunusova, Nailya; Madiyeva, Madina; Tanaka, Kimio; Hoshi, Masaharu; Kawano, Noriyuki; Noso, Yoshihiro; Takeichi, Nobuo; Rakhypbekov, Tolebay; Urazalina, Nailya; Dovgal, Galina; Rymbaeva, Tamara; Tokanova, Sholpan; Beisengazina, Meruert; Kembayeva, Kulypash; Inoue, Ken

2017-11-01

More than 400 nuclear explosion tests were conducted at the Semipalatinsk Nuclear Test Site (SNTS) and significant radioactive substances were released. The long-term consequences of the activities at the SNTS and the appearance of any hereditary effects remain insufficiently studied about 25 years after the test site was closed. The population living in villages near the SNTS are considered to have been heavily exposed to external and internal radiation. This study aims to perform an assessment and comprehensive cytogenetic analysis of the inhabitants living near the SNTS, and their first-(F1) and second-(F2) generation children. Residents of the East Kazakhstan region living in the area covered by the former SNTS were included in the study. To evaluate the hereditary effects of nuclear testing, comprehensive chromosome analyses were performed in lymphocytes using conventional Giemsa and fluorescent in situ hybridization methods in 115 F1 and F2 descendants in the villages of Dolon and Sarzhal, which were heavily contaminated. The parents of the subjects had permanently lived in the villages. A higher number of stable-type chromosome aberrations such as translocations was found in these residents than in 80 residents of the control area, Kokpecty, which indicates the possibility that radiation had biological effects on the exposed subjects.

Nutritional and other implications of irradiating meat

International Nuclear Information System (INIS)

Stevenson, M.H.

1994-01-01

Different methods have been developed to extend the shelf-life of meat and its products ranging from the traditional use of salt to canning, freezing and modified-atmosphere packaging. As well as these more conventional approaches to meat preservation, the use of ionizing radiation has also been extensively studied over many years. The irradiation sources which are permitted for use with food are gamma photons from 6o Co or 137 Cs, high-energy electrons generated by machines, maximum energy 10 MeV and X-rays with a maximum energy of 5 MeV (Codex Alimentarius Commission, 1984). At doses of about 25-50 kGy, irradiation can be used to achieve sterilization and in the 1960s shelf-stable radiation-sterilized meat products were developed to substitute for canned or frozen military rations. Currently, sterile meals are produced for immunocompromized patients using irradiation. With doses below 10 kGy, the process is effective in enhancing food safety through the inactivation of pathogenic microorganisms such as Salmonella and Campylobacter and extending shelf-life by eliminating the micro-organisms responsible for normal spoilage. Following the report of the Food and Agriculture Organization/International Atomic Energy Agency/World Health Organization Joint Expert Committee on the Wholesomeness of Irradiated Food (1981) which concluded that 'irradiation of food up to an overall average dose of 10 kGy produced no toxicological hazard and introduced no special nutritional or microbiological problems', there has been renewed interest in the use of lower doses of irradiation for the preservation of food. In 1991, the UK government introduced new regulations permitting the irradiation of seven categories of food, including chicken, under strictly controlled conditions (UK Government Regulations, 1990) .Currently, thirty-seven countries have approval for the irradiation treatment of a range of foods or food items and of these countries, twenty-six are using the process on a

Identification of irradiated potatoes by impedance

International Nuclear Information System (INIS)

Singh, Rita; Singh, Antaryami; Wadhawan, A.K.

1997-01-01

The electrical impedance of potatoes irradiated at 60, 90, 150 and 1000 Gy was measured using various frequencies of alternating current. The impedance of the irradiated potatoes was higher than the unirradiated potatoes particularly in the frequency range of 100 Hz to 10 kHz. The ratio of the impedance at 5 kHz to that at 50 Hz (Z5k/Z50) was found to be the best indicator for detection of radiation treatment. (author). 4 refs., 2 figs

Food irradiation: advantages and limitations

International Nuclear Information System (INIS)

Hernandes, N.K.; Vital, H. de C.; Sabaa-Srur, A.U.O.

2003-01-01

out on food irradiation in recent years. These studies showed that, if the safety and the benefits of food irradiation were properly explained, the consumers were willing to accept irradiated foods. Considering its potential role in the reduction of post-harvest losses, providing safe supply of food and overcoming quarantine barriers, food irradiation has received wider government approvals during the last decade. There is also a trend towards increased commercialization of irradiated food. Currently, there are 47 irradiation facilities in some 23 countries being used for treating foods for commercial purposes

Charge transport in non-irradiated and irradiated silicon detectors

International Nuclear Information System (INIS)

Leroy, C.; Roy, P.; Casse, G.L.; Glaser, M.; Grigoriev, E.; Lemeilleur, F.

1999-01-01

A model describing the transport of the charge carriers generated in n-type silicon detectors by ionizing particles is presented. In order to reproduce the experimental current pulse responses induced by α and β particles in non-irradiated and irradiated detectors up to fluences (PHI) much beyond the n to p-type inversion, an n-type region 15 μm deep is introduced on the p + side of the diode. This model also gives mobilities which decrease linearly up to fluences of around 5x10 13 particles/cm 2 and beyond, converging to saturation values of about 1000 and 450 cm 2 /V s for electrons and holes, respectively. The charge carrier lifetime degradation with increased fluence, due to trapping, is responsible for a predicted charge collection deficit for β particles and for α particles which is found to agree with direct CCE measurements. (author)

Cell kinetics of irradiated experimental tumors: cell transition from the non-proliferating to the proliferating pool

International Nuclear Information System (INIS)

Potmesil, M.; Goldfeder, A.

1980-01-01

In murine mammary carcinomas, parenchymal tumor cells with dense nucleoli traverse the cell cycle and divide, thus constituting the proliferating pool. Cells with trabeculate or ring-shaped nucleoli either proceed slowly through G 1 phase or are arrested in it. The role of these non-proliferating, G 1 phase-confined cells in tumor regeneration was studied in vivo after a subcurative dose of X-irradiation in two transplantable tumor lines. Tumor-bearing mice were continuously injected with methyl[ 3 H]thymidine before and after irradiation. Finally, the labeling was discontinued, mice injected with vincristine sulfate and cells arrested in metaphase were accumulated over 10-hrs. Two clearly delineated groups of vincristine-arrested mitoses emerged in autoradiograms prepared from tumor tissue at the time of starting tumor regrowth: one group with the silver-grain counts corresponding to the background level, the other with heavily labeled mitoses. As the only source of unlabeled mitoses was unlabeled G 1 phase-confined cells persisting in the tumor, this indicated cell transition from the non-proliferating to the proliferating pool, which took place in the initial phase of the tumor regrowth. Unlabeled progenitors have apparently remained in G 1 phase for at least 5-12 days after irradiation. (author)

AGC-2 Irradiation Report

Energy Technology Data Exchange (ETDEWEB)

Rohrbaugh, David Thomas [Idaho National Lab. (INL), Idaho Falls, ID (United States); Windes, William [Idaho National Lab. (INL), Idaho Falls, ID (United States); Swank, W. David [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2016-06-01

The Next Generation Nuclear Plant (NGNP) will be a helium-cooled, very high temperature reactor (VHTR) with a large graphite core. In past applications, graphite has been used effectively as a structural and moderator material in both research and commercial high temperature gas cooled reactor (HTGR) designs.[ , ] Nuclear graphite H 451, used previously in the United States for nuclear reactor graphite components, is no longer available. New nuclear graphites have been developed and are considered suitable candidates for the new NGNP reactor design. To support the design and licensing of NGNP core components within a commercial reactor, a complete properties database must be developed for these current grades of graphite. Quantitative data on in service material performance are required for the physical, mechanical, and thermal properties of each graphite grade with a specific emphasis on data related to the life limiting effects of irradiation creep on key physical properties of the NGNP candidate graphites. Based on experience with previous graphite core components, the phenomenon of irradiation induced creep within the graphite has been shown to be critical to the total useful lifetime of graphite components. Irradiation induced creep occurs under the simultaneous application of high temperatures, neutron irradiation, and applied stresses within the graphite components. Significant internal stresses within the graphite components can result from a second phenomenon—irradiation induced dimensional change. In this case, the graphite physically changes i.e., first shrinking and then expanding with increasing neutron dose. This disparity in material volume change can induce significant internal stresses within graphite components. Irradiation induced creep relaxes these large internal stresses, thus reducing the risk of crack formation and component failure. Obviously, higher irradiation creep levels tend to relieve more internal stress, thus allowing the

Consumer acceptance of irradiated food products: an apple marketing study

International Nuclear Information System (INIS)

Terry, D.E.; Tabor, R.L.

1990-01-01

This study was exploratory in nature, with emphasis on initial purchases and not repeat purchases or long-term loyalties to either irradiated or non-irradiated produce. The investigation involved the actual sale of irradiated and non-irradiated apples to consumers. Limited information about the process was provided, and apples were sold at roadside stands. Prices for the irradiated apples were varied while the price for the non-irradiated apples was held constant. Of these 228 West-Central Missouri shoppers, 101 (44%) bought no irradiated apples, 86 (38%) bought only irradiated apples, and 41 (18%) bought some of both types, Results of probit regressions indicated three significant independent variables. There was an inverse relationship between the price of irradiated apples and the probability of purchasing irradiated apples. There was a positive relationship between the purchasers’ educational level and the probability of purchasing irradiated apples. Predicted probabilities for belonging to categories in probit models were computed. Depending on particular equation specification, correctly placed were approximately 70 percent of the purchasers of the two categories--bought only non-irradiated apples, or bought some of both irradiated and non-irradiated apples or only irradiated apples. This study suggests that consumers may be interested in food irradiation as a possible alternative or supplement to current preservation techniques

Application of electron beam irradiation. 4. Treatment of pollutants by electron beam irradiation

International Nuclear Information System (INIS)

Tokunaga, Okihiro; Arai, Hidehiko

1994-01-01

Electron beam irradiation is capable of dissolving and removing pollutants, such as sulfur oxides, nitrogen oxides, and organic compounds, by easy production of OH radicals in flue gas and water. This paper deals with current status in the search for techniques for treating flue gas and waste water, using electron beam irradiation. Pilot tests have been conducted during the period 1991-1994 for the treatment of flue gas caused by coal and garbage burning and road tunnels. Firstly, techniques for cleaning flue gas with electron beams are outlined, with special reference to their characteristics and process of research development. Secondly, the application of electron beam irradiation in the treatment of waste water is described in terms of the following: (1) disinfection of sewage, (2) cleaning of water polluted with toxic organic compounds, (3) treatment for eliminating sewage sludge, (4) promotion of sewage sludge sedimentation, (5) disinfection and composting of sewage sludge, and (6) regeneration of activated carbon used for the treatment of waste water. (N.K.)

Rapid enhancement of nodal quasiparticle mass with heavily underdoping in Bi2212

Science.gov (United States)

Anzai, Hiroaki; Arita, Masashi; Namatame, Hirofumi; Taniguchi, Masaki; Ishikado, Motoyuki; Fujita, Kazuhiro; Ishida, Shigeyuki; Uchida, Shin-ichi; Ino, Akihiro

2018-05-01

We report substantial advance of our low-energy angle-resolved photoemission study of nodal quasiparticles in Bi2Sr2CaCu2O8+δ. The new data cover the samples from underdoped down to heavily underdoped levels. We also present the nodal Fermi velocities that determined by using an excitation-photon energy of hν = 7.0 eV over a wide doping range. The consistency between the results with hν = 8.1 and 7.0 eV allows us to rule out the effect of photoemission matrix elements. In comparison with the data previously reported, the nodal effective mass increases by a factor of ∼ 1.5 in going from optimally doped to heavily underdoped levels. We find a rapid enhancement of the nodal quasiparticle mass at low doping levels near the superconductor-to-insulator transition. The effective coupling spectrum, λ (ω) , is extracted directly from the energy derivatives of the quasiparticle dispersion and scattering rate, as a causal function of the mass enhancement factor. A steplike increase in Reλ (ω) around ∼ 65 meV is demonstrated clearly by the Kramers-Kronig transform of Imλ (ω) . To extract the low-energy renormalization effect, we calculated a simple model for the electron-boson interaction. This model reveals that the contribution of the renormalization at | ω | ≤ 15 meV to the quasiparticle mass is larger than that around 65 meV in underdoped samples.

Detection of irradiated spice in blend of irradiated and un-irradiated spices using thermoluminescence method

International Nuclear Information System (INIS)

Goto, Michiko; Yamazaki, Masao; Sekiguchi, Masayuki; Todoriki, Setsuko; Miyahara, Makoto

2007-01-01

Five blended spice sample were prepared by mixing irradiated and un-irradiated black pepper and paprika at different ratios. Blended black pepper containing 2%(w/w) of 5.4 kGy-irradiated black pepper showed no maximum at glow1. Irradiated black pepper samples, mixed to 5 or 10%(w/w), were identified as 'irradiated' or 'partially irradiated' or 'un-irradiated'. All samples with un-irradiated pepper up to 20%(w/w) were identified as irradiated'. In the case 5.0 kGy-irradiated paprika were mixed with un-irradiated paprika up to 5%(w/w), all samples were identified as irradiated'. The glow1 curves of samples, including irradiated paprika at 0.2%(w/w) or higher, exhibited a maximum between 150 and 250degC. The results suggest the existence of different critical mixing ratio for the detection of irradiation among each spices. Temperature range for integration of the TL glow intensity were compared between 70-400degC and approximate 150-250degC, and revealed that the latter temperature range was determined based on the measurement of TLD100. Although TL glow ratio in 150-250degC was lower than that of 70-400degC range, identification of irradiation was not affected. Treatment of un-irradiated black pepper and paprika with ultraviolet rays had no effect on the detection of irradiation. (author)

Comparison of human skin opto-thermal response to near-infrared and visible laser irradiations: a theoretical investigation

Energy Technology Data Exchange (ETDEWEB)

Dai Tianhong [Department of Bioengineering, Rice University, Houston, TX 77251 (United States); Pikkula, Brian M [Department of Bioengineering, Rice University, Houston, TX 77251 (United States); Wang, Lihong V [Department of Biomedical Engineering, Texas A and M University, College Station, TX 77843 (United States); Anvari, Bahman [Department of Bioengineering, Rice University, Houston, TX 77251 (United States)

2004-11-07

Near-infrared wavelengths are absorbed less by epidermal melanin, and penetrate deeper into human skin dermis and blood than visible wavelengths. Therefore, laser irradiation using near-infrared wavelengths may improve the therapeutic outcome of cutaneous hyper-vascular malformations in moderately to heavily pigmented skin patients and those with large-sized blood vessels or blood vessels extending deeply into the skin. A mathematical model composed of a Monte Carlo algorithm to estimate the distribution of absorbed light, numerical solution of a bio-heat diffusion equation to calculate the transient temperature distribution, and a damage integral based on an empirical Arrhenius relationship to quantify the tissue damage was utilized to investigate the opto-thermal response of human skin to near-infrared and visible laser irradiations in conjunction with cryogen spray cooling. In addition, the thermal effects of a single continuous laser pulse and micropulse-composed laser pulse profiles were compared. Simulation results indicated that a 940 nm wavelength induces improved therapeutic outcome compared with a 585 and 595 nm wavelengths for the treatment of patients with large-sized blood vessels and moderately to heavily pigmented skin. On the other hand, a 585 nm wavelength shows the best efficacy in treating small-sized blood vessels, as characterized by the largest laser-induced blood vessel damage depth compared with 595 and 940 nm wavelengths. Dermal blood content has a considerable effect on the threshold incident dosage for epidermal damage, while the effect of blood vessel size is minimal. For the same macropulse duration and incident dosage, a micropulse-composed pulse profile results in higher peak temperature at the basal layer of skin epidermis than an ideal single continuous pulse profile.

Validation of gamma irradiator controls for quality and regulatory compliance

International Nuclear Information System (INIS)

Harding, R.B.; Pinteric, F.J.A.

1995-01-01

Since 1978 the U.S. Food and Drug Administration (FDA) has had both the legal authority and the Current Good Manufacturing Practice (CGMP) regulations in place to require irradiator owners who process medical devices to produce evidence of Irradiation Process Validation. One of the key components of Irradiation Process Validation is the validation of the irradiator controls. However, it is only recently that FDA audits have focused on this component of the process validation. What is Irradiator Control System Validation? What constitutes evidence of control? How do owners obtain evidence? What is the irradiator supplier's role in validation? How does the ISO 9000 Quality Standard relate to the FDA's CGMP requirement for evidence of Control System Validation? This paper presents answers to these questions based on the recent experiences of Nordion's engineering and product management staff who have worked with several US-based irradiator owners. This topic - Validation of Irradiator Controls - is a significant regulatory compliance and operations issues within the irradiator suppliers' and users' community. (author)

Suppression of irradiation effects in gold-doped silicon detectors

International Nuclear Information System (INIS)

McPherson, M.; Sloan, T.; Jones, B.K.

1997-01-01

Two sets of silicon detectors were irradiated with 1 MeV neutrons to different fluences and then characterized. The first batch were ordinary p-i-n photodiodes fabricated from high-resistivity (400 Ω cm) silicon, while the second batch were gold-doped powder diodes fabricated from silicon material initially of low resistivity (20 Ω cm). The increase in reverse leakage current after irradiation was found to be more in the former case than in the latter. The fluence dependence of the capacitance was much more pronounced in the p-i-n diodes than in the gold-doped diodes. Furthermore, photo current generation by optical means was less in the gold doped devices. All these results suggest that gold doping in silicon somewhat suppresses the effects of neutron irradiation. (author)

An accurate measurement of the baryonic Tully-Fisher relation with heavily gas-dominated ALFALFA galaxies

NARCIS (Netherlands)

Papastergis, E.; Adams, E. A. K.; van der Hulst, J. M.

2016-01-01

We use a sample of 97 galaxies selected from the Arecibo legacy fast ALFA (ALFALFA) 21 cm survey to make an accurate measurement of the baryonic Tully-Fisher relation (BTFR). These galaxies are specifically selected to be heavily gas-dominated (Mgas/M∗ ≳ 2.7) and to be oriented edge-on. The former

Impact of irradiations by protons with different energies on silicon sensors

Energy Technology Data Exchange (ETDEWEB)

Neubueser, Coralie

2013-06-15

In the frame of the CMS tracker upgrade campaign the radiation damage of oxygenrich n-type silicon pad diodes induced by 23 MeV and 23 GeV protons was investigated. The diodes were manufactured by Hamamatsu Photonics. After irradiation with 1 MeV neutron equivalent fluences between 1 x 10{sup 11} cm{sup -2} and 1.5 x 10{sup 15} cm{sup -2}, the sensors were electrically characterized by means of capacitance-voltage (CV) and current-voltage (IV) measurements. Current pulses recorded by the Transient Current Technique (TCT) and Charge Collection Efficiency (CCE) measurements show a dependence of the bulk damage on the proton energy. At a fluence of {Phi}{sub eq}{approx}3 x 10{sup 14} cm{sup -2} oxygen-rich n-type diodes demonstrate clear Space Charge Sign Inversion (SCSI) after 23 MeV proton irradiation. This effect does not appear after the irradiation with 23 GeV protons. Moreover, RD50 pad diodes were irradiated with 23 MeV protons, electrically characterized and compared to results obtained after 23 GeV irradiations. Our previous observation on the energy dependence of the radiation damage could be confirmed. In order to get a deeper understanding of the differences of the radiation induced defects, the Deep Level Transient Spectroscopy (DLTS) and Thermally Stimulated Current Technique (TSC) were utilized. Defects with impact on the space charge could be identified and characterized and it was possible to find some hints for the reason of the SCSI after 23 MeV proton irradiation. Moreover, a dependence on the oxygen concentration of the sensors could be observed.

Surface Nano crystallization of 3Cr13 Stainless Steel Induced by High-Current Pulsed Electron Beam Irradiation

International Nuclear Information System (INIS)

Han, Z.; Zou, H.; Wang, Z.; Ji, I.; Cai, J.; Guan, Q.

2013-01-01

The nanocrystalline surface was produced on 3Cr13 martensite stainless steel surface using high-current pulsed electron beam (HCPEB) technique. The structures of the nano crystallized surface were characterized by X-ray diffraction and electron microscopy. Two nano structures consisting of fine austenite grains (50-150 nm) and very fine carbides precipitates are formed in melted surface layer after multiple bombardments via dissolution of carbides and crater eruption. It is demonstrated that the dissolution of the carbides and the formation of the supersaturated Fe (C) solid solution play a determining role on the microstructure evolution. Additionally, the formation of fine austenite structure is closely related to the thermal stresses induced by the HCPEB irradiation. The effects of both high carbon content and high value of stresses increase the stability of the austenite, which leads to the complete suppression of martensitic transformation.

Development of irradiation technique on controlling food contamination residue

International Nuclear Information System (INIS)

Liu Bin; Xiong Shanbai; Xiong Guangquan; Cheng Wei; Chen Yuxia; Liao Tao; Li Xin; Lin Ruotai

2010-01-01

The current state of the researches of irradiation technology on controlling food mycotoxin, pesticide, veterinary drugs and fishery drugs residue was summarized. And the degradation rate, mechanism, products and toxicities of food contamination were expatiated. The free radical from irradiation attack the site of weaker bond, and the less or more toxic substances were produced, which lead to the degradation of the food contamination. The limitations and future application of irradiation technique on controlling food contamination were also analyzed. (authors)

Status of irradiation testing and PIE of MOX (Pu-containing) fuel

International Nuclear Information System (INIS)

Dimayuga, F.C.; Zhou, Y.N.; Ryz, M.A.

1995-01-01

This paper describes AECL's mixed oxide (MOX) fuel-irradiation and post-irradiation examination (PIE) program. Post-irradiation examination results of two major irradiation experiments involving several (U, Pu)O 2 fuel bundles are highlighted. One experiment involved bundles irradiated to burnups ranging fro 400 to 1200 MWh/kgHe in the Nuclear Power Demonstration (NPD) reactor. The other experiment consisted of several (U, Pu)O 2 bundles irradiated to burnups of up to 500 Mwh/kgHe in the National Research Universal (NRU) reactor. Results of these experiments demonstrate the excellent performance of CANDU MOX fuel. This paper also outlines the status of current MOX fuel irradiation tests, including the irradiation of various (U, Pu)O 2 bundles. The strategic importance of MOX fuel to CANDU fuel-cycle flexibility is discussed. (author)

Degradation Of Aggregate Pollutant In Textiles Wastewater By Electron Beam Irradiation

International Nuclear Information System (INIS)

Khomsaton Abu Bakar; Zulkafli Ghazali; Siti Aiasah Hashim; Selambakkannu, S.; Ming, T.T.; Natasha Isnin; Hasnul Nizam Osman; Khasmidatul Akma Mohd Khairul Azmi

2016-01-01

Aggregate pollutant were refer to the mixture of the excess material that is used in the manufacturing proses of textiles, present in wastewater. This paper studies the effect of the beam energy, beam current and absorbed dose on degradation of aggregate pollutant in textiles effluent which was indicate by COD, pH and UV-Vis spectrum. The impact of beam energy was conducted when sample were exposed to the irradiation at various beam energy (1 to 3 MeV) at 20 mA and 17 kGy. The COD reduced from 495 mg/l to the range 398.00 -358 mg/l at beam energy 1 MeV to 3 MeV. The irradiated sample also slightly become more acidic at higher beam energy. While 1 MeV beam energy was sufficient to eliminate the exposed peak at wavelength of 425 nm, 550 nm and 650 nm in the UV spectrum. In the case effect of current, the COD effluent tested at constant beam energy of 1 MeV and 3 MeV at various beam current (3 mA, 5 mA, 10 mA, 15 mA and 20 mA) decreased with higher beam current. While interested peak in UV spectrum of irradiated samples was varnish at 3 mA beam current and 1 MeV energy applied. Considering to the 19.66 % COD removal and electric power used, 1 MeV beam energy and 20 mA beam current was the optimum irradiation parameter selected for this study. At 1 MeV:20 mA textiles wastewater irradiated at various dose of 17, 20, 25, 30, 35, 100 and 200 kGy shows removal of COD, were in the range 4.42 % - 30.09 %. (author)

A history of study on safety of irradiated foods (2). Clostridium botulinum in irradiated seafood from the reports by the United States Atomic Energy Commission

International Nuclear Information System (INIS)

Miyahara, Makoto

2004-01-01

This review is a part of ''history of study on the wholesomeness of irradiated foods''. Clostridium botulinum in irradiated seafood have been of great concern at the beginning of development of irradiated food. This review describes the studies on Clostridium botulinum by US. Atomic Energy Commission in 1960's with their data and what they recognized it as a risk factor of irradiated foods. In 1999 FAO/IAEA/WHO reported that Clostridium botulinum type A and B spors are apparently the most resistant and thus of great concern in the radiation sterilization of food, whereas the less radiation-resistant type E spores are important in low dose irradiation of foods, particularly fishery products. This review also describes current break-through application by NASA and Canadian irradiator. (author)

Irradiation defect structures in YBa2Cu3O7-x and their correlation with superconducting properties

International Nuclear Information System (INIS)

Kirk, M.A.

1990-11-01

We review our work on irradiation effects in single crystal YBa 2 CU 3 O 7-x . Transmission electron microscopy has been employed to study the defect microstructures produced by irradiations with fast neutrons, MeV ions (Kr, Ne and p), and electrons. The atomic structure within defect cascades was investigated using 50 keV Kr and Xe ion irradiations to low doses. Evidence is shown for an amorphous structure with some incoherent recrystallization within individual cascades. Correlation with enhancements in critical current density produced by neutron irradiations suggest that this cascade structure effectively pins magnetic flux lines. At sufficiently high fluences of fast neutrons or MeV Kr and Ne ions, a cellular microstructure is found. This structure consists of cells or microcrystallites of good cystalline and superconducting material (in the case of neutron irradiation), with cell walls of amorphous material. Full amorphization proceeds with the growth of cell wall volume. The formation of this microstructure coincides with a decrease in critical transport current, but is not observed by magnetization measurements. Increases in critical current density under proton irradiation, comparable to those produced by neutron irradiation, have been reported. The defect structure produced by proton irradiations is examined here and found to differ from that of neutron irradiations. Our most recent measurements of changes in critical temperature and current density, and defect microstructure following electron irradiations will be described. 20 refs., 6 figs

Testing of high current by-pass diodes for the LHC magnet quench protection

International Nuclear Information System (INIS)

Berland, V.; Hagedorn, D.; Rodriguez-Mateos, F.

1996-01-01

Within the framework of the Large Hadron Collider (LHC) R and D program, CERN is performing experiments to establish the current carrying capability of irradiated diodes at liquid Helium temperatures for the superconducting magnet protection. Even if the diodes are degraded by radiation dose and neutron fluence, they must be able to support the by-pass current during a magnet quench and the de-excitation of the superconducting magnet ring. During this discharge, the current in the diode reaches a maximum value up to 13 kA and decreased with an exponential time constant of 100 s. Two sets of 75 mm wafer diameter epitaxial diodes, one irradiated and one non-irradiated, were submitted to this experiment. The irradiated diodes have been exposed to radiation in the accelerator environment up to 20 kGy and then annealed at room temperature. After the radiation exposure the diodes had shown a degradation of forward voltage of 50% which reduced to about 14% after the thermal annealing. During the long duration high current tests, one of the diodes was destroyed and the other two irradiated diodes showed a different behavior compared with non-irradiated diodes

Electron beam influence on the carbon contamination of electron irradiated hydroxyapatite thin films

International Nuclear Information System (INIS)

Hristu, Radu; Stanciu, Stefan G.; Tranca, Denis E.; Stanciu, George A.

2015-01-01

Highlights: • Carbon contamination mechanisms of electron-beam-irradiated hydroxyapatite. • Atomic force microscopy phase imaging used to detect carbon contamination. • Carbon contamination dependence on electron energy, irradiation time, beam current. • Simulation of backscattered electrons confirms the experimental results. - Abstract: Electron beam irradiation which is considered a reliable method for tailoring the surface charge of hydroxyapatite is hindered by carbon contamination. Separating the effects of the carbon contamination from those of irradiation-induced trapped charge is important for a wide range of biological applications. In this work we focus on the understanding of the electron-beam-induced carbon contamination with special emphasis on the influence of the electron irradiation parameters on this phenomenon. Phase imaging in atomic force microscopy is used to evaluate the influence of electron energy, beam current and irradiation time on the shape and size of the resulted contamination patterns. Different processes involved in the carbon contamination of hydroxyapatite are discussed

Projection of the annealing behavior of irradiated Si sensors in the LHC environment

CERN Document Server

Chatterji, S; Bhardwaj, N; Chauhan, S S; Choudhary, B C; Gupta, P; Jha, M; Kumar, A; Naimuddin, M; Ranjan, K; Shivpuri, R K; Srivastava-Ajay, K

2004-01-01

The study of the radiation tolerance and subsequent annealing effects on p+-n-n+ silicon micro strip detectors has been performed as a part of R&D program for the preshower detector in the CMS experiment. CMS silicon strip sensors were irradiated with 24 GeV protons at CERN proton synchrotron (PS) to a total fluence of 3*10/sup 14/ p/cm/sup 2 /. Sensors were stored in freezer after irradiation and I-V and C-V measurements were carried out. Variation in full depletion voltage and leakage current have been studied as a function of annealing time. The breakdown performance of the device actually improves after irradiation due to the beneficial effect of type-inversion. The breakdown voltage increases further with annealing time. However, the leakage current increases tremendously just after irradiation. As the sensors are annealed, there is a drop in leakage current. The rate of annealing is observed to be temperature dependent. Hence in terms of leakage current, it seems that room temperature annealing is b...

The 1989 progress report: Irradiated solids

International Nuclear Information System (INIS)

Novion, C. de.

1989-01-01

The 1989 activity report of the laboratory of Irradiated Solids of the Polytechnic School (France) is presented. Investigations on disordered solids are the main field of research. Disorder and its consequences on the physical properties of materials are studied. Some of the most important results are: the experimental demonstration of the creation of defects by electron excitation in iron; the precipitation induced by the irradiation of high temperature electrons; the demonstration of an additional trapping of magnetic flux lines and the increase of the critical current in the YBa2Cu307 superconducting oxyde [fr

The role of thresholds in the response of lambs to vaccination with irradiated Trichostrongylus colubriformis larvae

International Nuclear Information System (INIS)

Windon, R.G.; Dineen, J.K.; Gregg, P.; Donald, A.D.; Griffiths, D.A.

1984-01-01

A piecewise logarithmic model fitted to worm counts of ewe lambs vaccinated and challenged in pens with a range of doses of irradiated and normal Trichostrongylus colubriformis larvae respectively, indicated that the threshold for response to both vaccine (V 0 =4400) and challenge dose is exceeded by 5000 larvae. Whereas response was vaccine dose dependent, it was independent of challenge dose. Ram lambs vaccinated at low dose levels were as resistant against challenge as ewe lambs, but by contrast, failed to show increased protection after vaccination with high doses of irradiated larvae. Serum titre of antiworm complement-fixing antibodies at the time of challenge also indicated that ram lambs were less responsive immunologically than ewe lambs following vaccination at the higher dose levels. A field study showed that response to vaccination was only apparent after transfer of the sheep to heavily contaminated pastures, suggesting that previous exposure of the vaccinated animals to the low dose of infective larvae available on a lightly contaminated pasture constituted a challenge which was below the threshold. (author)

Irradiation behavior of German PWR RPV steels under operating conditions

Energy Technology Data Exchange (ETDEWEB)

May, J.; Hein, H. [AREVA NP Gmbh (Germany); Ganswind, J. [VGB PowerTech e.V. (Germany); Widera, M. [RWE Power AG (Germany)

2011-07-01

In 2007, the last standard surveillance capsule of the original RPV (Reactor Pressure Vessel) surveillance programs of the 11 currently operating German PWR has been evaluated. With it the standard irradiation surveillance programs of these plants was completed. In the present paper, irradiation data of these surveillance programs will be presented and a final assessment of the irradiation behavior of the German PWR RPV steels with respect to current standards KTA 3203 and Reg. Guide 1.99 Rev. 2 will be given. Data from two units which are currently under decommissioning will also be included, so that data from all 13 German PWR manufactured by the former Siemens/KWU company (now AREVA NP GmbH) are shown. It will be shown that all surveillance data within the approved area of chemical composition verify the limit curve RT(limit) of the KTA 3203, which is the relevant safety standard for these plants. An analysis of the data shows, that the prediction formulas of Reg. Guide 1.99 Rev. 2 Pos. 1 or from the TTS model tend to overestimate the irradiation behavior of the German PWR RPV steels. Possible reasons for this behavior are discussed. Additionally, the data will be compared to data from the research project CARISMA to demonstrate that these data are representative for the irradiation behavior of the German PWR RPV steels. Since the data of these research projects cover a larger neutron fluence range than the original surveillance data, they offer a future outlook into the irradiation behavior of the German PWR RPV steels under long term conditions. In general, as a consequence of the relatively large and beneficial water gap between core and RPV, especially in all Siemens/KWU 4-loop PWR, the EOL neutron fluence and therefore the irradiation induced changes in mechanical properties of the German PWR RPV materials are rather low. Moreover the irradiation data indicate that the optimized RPV materials specifications that have been applied in particular for the

Stored energy and annealing behavior of heavily deformed aluminium

DEFF Research Database (Denmark)

Kamikawa, Naoya; Huang, Xiaoxu; Kondo, Yuka

2012-01-01

It has been demonstrated in previous work that a two-step annealing treatment, including a low-temperature, long-time annealing and a subsequent high-temperature annealing, is a promising route to control the microstructure of a heavily deformed metal. In the present study, structural parameters...... are quantified such as boundary spacing, misorientation angle and dislocation density for 99.99% aluminium deformed by accumulative roll-bonding to a strain of 4.8. Two different annealing processes have been applied; (i) one-step annealing for 0.5 h at 100-400°C and (ii) two-step annealing for 6 h at 175°C...... followed by 0.5 h annealing at 200-600°C, where the former treatment leads to discontinuous recrystallization and the latter to uniform structural coarsening. This behavior has been analyzed in terms of the relative change during annealing of energy stored as elastic energy in the dislocation structure...

Softening of metals under hydrogen ion irradiation

International Nuclear Information System (INIS)

Guseva, M.I.; Korshunov, S.N.; Martynenko, Yu.V.; Skorlupkin, I.D.

2005-01-01

Experimental study results are presented on steel type 18-10 creep under hydrogen ion irradiation. The Irradiation of annealed specimens is accomplished by 15 keV H 2 + ions with a dose up to 10 22 m -2 at current density of 0.6 A/m 2 at temperatures of 570-770 K. Creep tests show that the irradiation at T = 770 K results in a sharp increase of creep rate. At t 570 K the effect of ion-induced creep in steel 18-10 is not observed. The model is proposed which explains the ion-induced creep by accumulation of hydrogen along grain boundaries, their weakening and removal of obstacles to sliding [ru

Performance studies under high irradiation of resistive bulk-micromegas chambers at the CERN Gamma Irradiation Facility

CERN Document Server

Sidiropoulou, Ourania; Bortfeldt, J; Farina, E; Iengo, P; Longo, L; Sidiropoulou, O; Wotschack, J

2017-01-01

Radiation studies on several resistive bulk-Micromegas chambers produced at CERN will be viewed in this document. Two resistive bulk-Micromegas chambers have been installed at the CERN Gamma Irradiation Facility (GIF++) exposed to an intense gamma irradiation with the aim of evaluating the detector behaviour under high irradiation and carrying out a long-term age- ing study. The chambers under study have an active area of 10 x 10 cm 2 , a strip pitch of 400 m m , an ampli- fication gap of 128 m m , and a drift gap of 5 mm. The results on the detector performance as a function of the photon flux up to 44 MHz/cm 2 will be shown as well as the ageing properties as function of the integrated charge and the current intensity and its stability with time. In addition, the results of the efficiency measurements before, during, and after the irradiation will also be presented as a function of the amplification voltage at which the chambers are operated.

Low-temperature deuteron irradiation of differently reacted Nb3Sn superconductors

International Nuclear Information System (INIS)

Maier, P.; Seibt, E.

1978-01-01

Irradiation measurements with 50 MeV deuterons at 18 K and subsequent annealing measurements were performed on Nb 3 Sn single and multifilamentary superconductors at the Helium-Bath Irradiation Facility of the Karlsruhe Cyclotron. The critical current densities jsub(c) of Nb 3 Sn bronze-reacted wire samples at various reaction temperatures (Tsub(R)=650,700,750,800 and 850 0 C) with equal layer thickness were measured for integral deuteron fluxes up to PHIsub(t)=0.7x10 18 cm -2 . After a decrease in jsub(c) of 85% at maximum dose a relatively small annealing effect (4 to 10%) was observed at ambient temperatures. The maximum value of the normalized critical current density, jsub(c)/jsub(c0), at PHIsub(t)approximately=10 17 cm -2 increases with increasing reaction temperature. The difference in volume pinning forces before and after irradiation increases less than linear (approximately√PHIsub(t)) with the irradiation dose. An almost linear dependence between the inverse grain diameter (dsub(K) -1 )) and volume pinning force is obtained both before and after irradiation. (Auth.)

Charging effects of PET under electron beam irradiation in a SEM

International Nuclear Information System (INIS)

Jbara, O; Rondot, S; Hadjadj, A; Patat, J M; Fakhfakh, S; Belhaj, M

2008-01-01

This paper deals with charge trapping and charge transport of polyethylene terephthalate (PET) polymer subjected to electron irradiation in a scanning electron microscope (SEM). Measurement of displacement current and leakage current using an arrangement adapted to the SEM allows the amount of trapped charge during and after electron irradiation to be determined and the charge mechanisms regulation to be studied. These mechanisms involve several parameters related to the electronic injection, the characteristics of insulator and the effects of the trapped charge itself. The dynamic trapping properties of PET samples are investigated and the time constants of charging are evaluated for various conditions of irradiation. The determination of the trapping cross section for electrons is possible by using the trapping rate at the onset of irradiation. Many physical processes are involved in the charging and discharging mechanisms; among them surface conduction is outlined. Through the control of irradiation conditions, various types of surface discharging (flashover phenomenon) behaviour are also observed. The strength of the electric field initiating surface discharge is estimated.

Irradiated food: too hot to handle?

International Nuclear Information System (INIS)

Coghlan, Andy.

1990-01-01

This article discusses current arguments for and against the irradiation of food for human consumption. The technique, which involves bombarding batches of food with gamma rays, x rays or accelerated electrons, is claimed to halt spoilage, kill bacteria and thus extend the shelf-life of various foodstuffs. Irradiated foods are at present indistinguishable from non-irradiated food and this problem may not be solved before the government's bill legalizes the process. Opponents claim the technique may not be safe and that the food industry may use it to fool consumers into buying rotten foods. Proponents say that even though many foods, such as poultry, seafood, fruits, vegetables and spices may be treated, it is unlikely that more than a small proportion will be. They reject safety worries as alarmist exaggeration. (UK)

The effect of fast particles' irradiation on electrooptical properties of GaP LEDs

International Nuclear Information System (INIS)

Gontaruk, O.; Kovalenko, A.; Malyj, E.; Petrenko, I.; Pinkovska, M.; Polivtcev, L.; Tartachnyk, V.

2013-01-01

The electrooptical properties of industrial AL 102 GaP light-emitting diodes (LEDs) irradiated with fast particles have been studied. 2 MeV electrons and fast reactor neutrons were used and devices' microplsma emitting, current-voltage and capacitance-voltage characteristics were measured. It was shown that electron irradiation in the range (2-5)10 16 cm -2 leads to the drop of microplasma emitting intensity, decrease of capacity and reverse currents and increase of reverse bias. The annealing study of current-voltage characteristics after neutron irradiation of diodes confirms the assumption about prevailing radiation influence on diode base due to induce of deep levels. (authors)

Fusion Materials Irradiation Test Facility: experimental capabilities and test matrix

International Nuclear Information System (INIS)

Opperman, E.K.

1982-01-01

This report describes the experimental capabilities of the Fusion Materials Irradiation Test Facility (FMIT) and reference material specimen test matrices. The description of the experimental capabilities and the test matrices has been updated to match the current single test cell facility ad assessed experimenter needs. Sufficient detail has been provided so that the user can plan irradiation experiments and conceptual hardware. The types of experiments, irradiation environment and support services that will be available in FMIT are discussed

Training manual on food irradiation technology and techniques. 2. ed.

International Nuclear Information System (INIS)

1982-01-01

The objective of the revised Training Manual is to help scientists to acquire the necessary knowledge needed for performing proper research and development work in the field of food irradiation. The Manual presents an up-to-date picture of the current state of food irradiation and reflects the important advances made in the technology of food irradiation, in the radiation chemistry of foods, in the microbiology of irradiated foods, in wholesomeness and standardization. It contains the following chapters: (1) Radionuclides and radiation; (2) Radiation detection and measurement; (3) Radiation protection; (4) Radiation chemistry; (5) Effects of radiation on living organisms; (6) Preservation of foods; (7) Radiation preservation of foods; (8) Packaging; (9) Combination processes; (10) Limitations of food irradiation; (11) Wholesomeness of irradiated foods; (12) Government regulation of irradiated foods; (13) Food irradiation facilities; (14) Commercial aspects of food irradiation; (15) Literature sources. The practical part of the Manual contains a revised and expanded series of detailed laboratory exercises in the use of ionizing radiation for food processing

Cost evaluation of irradiation system with electron accelerator

International Nuclear Information System (INIS)

Kashiwagi, M.

2003-01-01

The features of electron beam irradiation system using electron accelerator are direct energy pour into the irradiated material, no third material mixture such as catalyst, suitable for mass production and easy operation and maintenance work available. These features can bring the various applications such as cross-linking action, graft polymerization, radical polymerization and others. The selection of electron accelerator ratings is made under consideration of quality, width and thickness of irradiated material, production amount, dose required for reaction and irradiation atmosphere. Especially in a case of irradiation of wire with high insulation material such as polyethylene, the consideration of maximum thickness toward irradiation direction is necessary to avoid the discharge (Lichtenberg discharge) by charged-up electrons inside insulation material. Therefore, the acceleration voltage should be selected to make the maximum penetration larger than maximum irradiation thickness. The actual model case of estimate the irradiation cost was selected that the irradiation object was polyethylene insulated wire up to AWG no.14, irradiation amount was 5,000 km/month, necessary dose was 200 kGy, operation time was 22 d/month and 8 h/day and actual operation efficiency was considered loss time such as bobbin changing as 80%. The selected ratings of electron accelerator were acceleration voltage of 800 kV, beam current of 100 mA and irradiation width of 180 cm with irradiation pulleys stand of 60 turns x 3 lanes. The initial total cost was estimated as 3 M$(US) and operation cost was evaluated as 215 k$(US). Therefore, the irradiation cost of wire was evaluated as 0.0036 $/m. (author)

Local graft irradiation in renal transplant rejection

International Nuclear Information System (INIS)

Kawamura, Masashi; Kataoka, Masaaki; Itoh, Hisao

1990-01-01

From 1977 to 1988, of 142 renal transplantations, seven recipients (4.9%) received local graft irradiation following rejective reaction refractory to antirejection medical managements. Concurrent with the administration of pulsed high dose methylprednisolone and other antirejection medical managements, the graft was irradiated with a total dose of 6.0 Gy-150 cGy per fraction every other day at the midplane of the graft using two opposing portals of 4MX Linac. The fields were defined by palpation and echography. All patients had improvements in serum creatinine on the 10th day after beginning the irradiation. Four patients with peripheral lymphocytosis during the irradiation combined with pulsed high dose methylprednisolone improved in renal functions. On the other hand, out of 3 patients with lymphcytopenic changes, in two the transplanted graft was removed due to deteriorations, and the other patient is currently suffering from chronic rejection. Local graft irradiation can be useful in maintaining a rejective graft and reversing its functions in some patients whose rejective reaction failed to respond to the antirejection medical managements. (author)

Influence of irradiation on the switching behavior in PZT thin films

International Nuclear Information System (INIS)

Baturin, I.; Menou, N.; Shur, V.; Muller, C.; Kuznetsov, D.; Hodeau, J.-L.; Sternberg, A.

2005-01-01

Spatially nonuniform imprint behavior induced by X-ray synchrotron, electron and neutron irradiation has been investigated in sol-gel Pb(Zr,Ti)O 3 thin films. The analysis of the switching current data reveals the strong influence of irradiation on the switching current shape. The obtained effects have been explained as a result of acceleration of the bulk screening process induced by irradiation. It was shown that the spatial distribution of the internal bias field is determined by the domain structure existing during irradiation. The changes in the structural characteristics during fatigue cycling have been reveled by high resolution synchrotron X-ray diffraction experiments on (1 1 1)-oriented PZT-based capacitors with a composition in the morphotropic region. From both ex situ and in situ measurements, microstructural changes with cyclic switching during fatigue have been evidenced and correlated with the evolution of the switching characteristics

Computer-controlled gamma-ray scanner for irradiated reactor fuel

International Nuclear Information System (INIS)

Mandler, J.W.; Coates, R.A.; Killian, E.W.

1979-01-01

Gamma-ray scanning of irradiated fuel is an important nondestructive technique used in the thermal fuels behavior program currently under way at the Idaho National Engineering Laboratory. This paper is concerned with the computer-controlled isotopic gamma-ray-scanning system developed for postirradiation examination of fuel and includes a brief discussion of some scan results obtained from fuel rods irradiated in the Power-Burst Facility to illustrate gamma-ray spectrometry for this application. Both burnup profiles and information concerning fission-product migration in irradiated fuel are routinely obtained with the computer-controlled system

Irradiation tests of ATLAS liquid argon forward calorimeter (FCAL) electronics components

CERN Document Server

Leroy, C; Golikov, V; Golubyh, S M; Kukhtin, V; Kulagin, E; Luschikov, V; Merkulov, L; Minashkin, V F; Shalyugin, A N

2002-01-01

FCAL resistors, capacitors, and transformers together with capacitors and sintimid disks of the purity monitor have been irradiated in liquid argon to study their possible lead to argon pollution at a maximal neutron fluence of 1016 n cm-2 at the IBR-2 reactor of JINR, Dubna. The results of charge collection measurements before and after irradiation are reported. Electrical measurement on these FCAL capacitors, resistors and transformers were also performed after irradiation. In general, the results of resistance, capacitance, impedance, leakage current and high voltage breakdown measurements after irradiation show minor changes of value only for some parameters from nominal values or values measured before irradiation.

Gamma irradiation influence on physical properties of milk proteins

International Nuclear Information System (INIS)

Ciesla, K.; Salmieri, S.; Lacroix, M.; Le Tien, C.

2004-01-01

Gamma irradiation was found to be an effective method for the improvement of both barrier and mechanical properties of the edible films and coatings based on calcium and sodium caseinates alone or combined with some globular proteins. Our current studies concern gamma irradiation influence on the physical properties of calcium caseinate-whey protein isolate-glycerol (1:1:1) solutions and gels, used for films preparation. Irradiation of solutions was carried out with Co-60 gamma rays applying 0 and 32 kGy dose. The increase in viscosity of solutions was found after irradiation connected to induced crosslinking. Lower viscosity values were detected, however, after heating of the solutions irradiated with a 32 kGy dose than after heating of the non-irradiated ones regarding differences in the structure of gels and resulting in different temperature-viscosity curves that were recorded for the irradiated and the non-irradiated samples during heating and cooling. Creation of less stiff but better ordered gels after irradiation arises probably from reorganisation of aperiodic helical phase and β-sheets, in particular from increase of β-strands, detected by FTIR. Films obtained from these gels are characterised by improved barrier properties and mechanical resistance and are more rigid than those prepared from the non-irradiated gels. The route of gel creation was investigated for the control and the irradiated samples during heating and the subsequent cooling

Gamma irradiation influence on physical properties of milk proteins

Energy Technology Data Exchange (ETDEWEB)

Ciesla, K. E-mail: kciesla@orange.ichtj.waw.pl; Salmieri, S.; Lacroix, M.; Le Tien, C

2004-10-01

Gamma irradiation was found to be an effective method for the improvement of both barrier and mechanical properties of the edible films and coatings based on calcium and sodium caseinates alone or combined with some globular proteins. Our current studies concern gamma irradiation influence on the physical properties of calcium caseinate-whey protein isolate-glycerol (1:1:1) solutions and gels, used for films preparation. Irradiation of solutions was carried out with Co-60 gamma rays applying 0 and 32 kGy dose. The increase in viscosity of solutions was found after irradiation connected to induced crosslinking. Lower viscosity values were detected, however, after heating of the solutions irradiated with a 32 kGy dose than after heating of the non-irradiated ones regarding differences in the structure of gels and resulting in different temperature-viscosity curves that were recorded for the irradiated and the non-irradiated samples during heating and cooling. Creation of less stiff but better ordered gels after irradiation arises probably from reorganisation of aperiodic helical phase and {beta}-sheets, in particular from increase of {beta}-strands, detected by FTIR. Films obtained from these gels are characterised by improved barrier properties and mechanical resistance and are more rigid than those prepared from the non-irradiated gels. The route of gel creation was investigated for the control and the irradiated samples during heating and the subsequent cooling.

Enhanced vortex pinning and critical current density in proton-irradiated YBa2Cu3O7-δ thin films

International Nuclear Information System (INIS)

Venturini, E.L.; Siegal, M.P.; White, A.E.; Hou, S.Y.; Phillips, J.M.

1992-01-01

The appropriate fluence of 2.0 MeV H + ions has been shown previously to enhance the critical current density J c by a factor of two at a magnetic field of 0.9 tesla in 1000 Angstrom thick epitaxial films of YBa 2 Cu 3 O 7-δ grown by the ex situ BaF 2 process. The as-grown films exhibit single crystal-like behavior in both atomic ordering and J c versus temperature and magnetic field. TRIM simulations suggest that H + irradiation generates mainly point defects throughout the crystal structure. We show here that such defects produce both a large enhancement of J c for fields above 1 tesla and a significant increase in the apparent vortex pinning potential deduced from magnetization relaxation data

Detection of irradiated spices by thermoluminescence analysis

International Nuclear Information System (INIS)

Hammerton, K.M.; Banos, C.

1996-01-01

Spices are used extensively in prepared foods. The high levels of contamination of many spices with microorganisms poses a problem for the food industry. Irradiation treatment is the most effective means of reducing the microbial load to safe levels. Although the process is currently subject to a moratorium in Australia, it is used in several countries for the decontamination of spices. Methods for detecting irradiation treatment of spices are necessary to enforce compliance with labelling requirements or with a prohibition on the sale of irradiated foods. Thermoluminescence (TL) analysis of spice samples has been shown to be an applicable method for the detection of all irradiated spices. It was established that the TL response originates from the adhering mineral dust in the sample. Definitive identification of many irradiated spices requires the separation of a mineral extract from the organic fraction of the spice sample. This separation can be achieved by using density centrifugation with a heavy liquid, sodium polytungstate. Clear discrimination between untreated and irradiated spice samples has been obtained by re-irradiation of the mineral extract after the first TL analysis with an absorbed dose of about 1 kGy (normalisation). The ratio of the first to second TL response was about one for irradiated samples and well below one for untreated samples. These methods have been investigated with a range of spices to establish the most suitable method for routine control purposes. (author)

Effects of irradiation on the components of implantable pacemakers

CERN Document Server

Kawamura, S; Kuga, N; Shiba, T; Hirose, T; Fujimoto, H; Toyoshima, T; Hyodo, K; Matoba, M

2003-01-01

The purpose of this study was to examine the effects of irradiation on implantable pacemaker components. The pacemaker was divided into three components: lead wire and electrode, battery, and electrical circuit, and each component was irradiated by X-ray and electron beams, respectively. The pacemaker parameters were measured by both telemetry data of the programmer and directly measured data from the output terminal. The following results were obtained. For the lead wire and electrode, there was no effect on the pacemaker function due to irradiation by X-ray and electron beams. In the case of battery irradiation, there was no change in battery voltage or current up to 236 Gy X-ray dose. In the electrical circuit, the pacemaker reverted to the regular beating rate (fixed-rate mode) immediately after the start of X-ray irradiation, and it continued in this mode during irradiation. In patients with their own heartbeat rhythm, changing to the fixed-rate mode may cause dangerous conditions such as ventricular fib...

Performance of a proton irradiation chamber

International Nuclear Information System (INIS)

Agosteo, S.; Borsato, E.; Dal Corso, F.; Fazzi, A.; Gonella, F.; Introini, M.V.; Lippi, I.; Lorenzoli, M.; Modenese, L.; Montecassiano, F.; Pegoraro, M.; Pola, A.; Varoli, V.; Zotto, P.

2012-01-01

A Proton Irradiation Chamber aiming to perform radiation tests of electronic components was developed. The precision on the measurement of the ion currents was pushed beyond the resolution of the picoammeter by means of a series of collimators on the beam showing a linear correlation among the currents measured on them and the smaller, not measurable, current on the target. As an example of the obtained results the tests done on a Si microdosimeter and a power p-MOS are reported.

Performance of a proton irradiation chamber

Energy Technology Data Exchange (ETDEWEB)

Agosteo, S. [INFN, Sezione di Milano, via Celoria 16, 20133 Milano (Italy); Politecnico di Milano, Dipartimento di Energia, Sezione di Ingegneria Nucleare-CeSNEF, via Ponzio 34/3 20133 Milano (Italy); Borsato, E. [INFN, Sezione di Padova, via Marzolo 8, 35131 Padova (Italy); Universita di Padova, Dipartimento di Fisica, via Marzolo 8, 35131 Padova (Italy); Dal Corso, F. [INFN, Sezione di Padova, via Marzolo 8, 35131 Padova (Italy); Fazzi, A. [INFN, Sezione di Milano, via Celoria 16, 20133 Milano (Italy); Politecnico di Milano, Dipartimento di Energia, Sezione di Ingegneria Nucleare-CeSNEF, via Ponzio 34/3 20133 Milano (Italy); Gonella, F. [INFN, Sezione di Padova, via Marzolo 8, 35131 Padova (Italy); Introini, M.V. [INFN, Sezione di Milano, via Celoria 16, 20133 Milano (Italy); Politecnico di Milano, Dipartimento di Energia, Sezione di Ingegneria Nucleare-CeSNEF, via Ponzio 34/3 20133 Milano (Italy); Lippi, I. [INFN, Sezione di Padova, via Marzolo 8, 35131 Padova (Italy); Lorenzoli, M. [INFN, Sezione di Milano, via Celoria 16, 20133 Milano (Italy); Politecnico di Milano, Dipartimento di Energia, Sezione di Ingegneria Nucleare-CeSNEF, via Ponzio 34/3 20133 Milano (Italy); Modenese, L.; Montecassiano, F.; Pegoraro, M. [INFN, Sezione di Padova, via Marzolo 8, 35131 Padova (Italy); Pola, A.; Varoli, V. [INFN, Sezione di Milano, via Celoria 16, 20133 Milano (Italy); Politecnico di Milano, Dipartimento di Energia, Sezione di Ingegneria Nucleare-CeSNEF, via Ponzio 34/3 20133 Milano (Italy); Zotto, P., E-mail: pierluigi.zotto@pd.infn.it [INFN, Sezione di Padova, via Marzolo 8, 35131 Padova (Italy); Universita di Padova, Dipartimento di Fisica, via Marzolo 8, 35131 Padova (Italy)

2012-02-01

A Proton Irradiation Chamber aiming to perform radiation tests of electronic components was developed. The precision on the measurement of the ion currents was pushed beyond the resolution of the picoammeter by means of a series of collimators on the beam showing a linear correlation among the currents measured on them and the smaller, not measurable, current on the target. As an example of the obtained results the tests done on a Si microdosimeter and a power p-MOS are reported.

Study of the Effect of Swelling on Irradiation Assisted Stress Corrosion Cracking

Energy Technology Data Exchange (ETDEWEB)

Teysseyre, Sebastien Paul [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2016-09-01

This report describes the methodology used to study the effect of swelling on the crack growth rate of an irradiation-assisted stress corrosion crack that is propagating in highly irradiated stainless steel 304 material irradiated to 33 dpa in the Experimental Breeder Reactor-II. The material selection, specimens design, experimental apparatus and processes are described. The results of the current test are presented.

Enhanced defects recombination in ion irradiated SiC

International Nuclear Information System (INIS)

Izzo, G.; Litrico, G.; Grassia, F.; Calcagno, L.; Foti, G.

2010-01-01

Point defects induced in SiC by ion irradiation show a recombination at temperatures as low as 320 K and this process is enhanced after running current density ranging from 80 to 120 A/cm 2 . Ion irradiation induces in SiC the formation of different defect levels and low-temperature annealing changes their concentration. Some levels (S 0 , S x and S 2 ) show a recombination and simultaneously a new level (S 1 ) is formed. An enhanced recombination of defects is besides observed after running current in the diode at room temperature. The carriers introduction reduces the S 2 trap concentration, while the remaining levels are not modified. The recombination is negligible up to a current density of 50 A/cm 2 and increases at higher current density. The enhanced recombination of the S 2 trap occurs at 300 K, which otherwise requires a 400 K annealing temperature. The process can be related to the electron-hole recombination at the associated defect.

Dark Current Measurements in GIF++

CERN Document Server

Al-Qahtani, Abdulaziz

2017-01-01

This project revolved around creating a code that treats experiment files in order to fetch dark current measurements done for the Cathode Strip Chambers (CSC) exposed to long-term irradiation at Gamma Irradiation Facility (GIF++) and plot the results as functions of the accumulated charge. This paper will discuss the Compact Muon Solenoid (CMS) experiment, the CSCs that we have looked at (specifically the muon detectors located at the CMS endcaps), longevity test at GIF++, and finally discuss the code and results obtained.

Therapy of infections in mice irradiated in mixed neutron/photon fields and inflicted with wound trauma: a review of current work.

Science.gov (United States)

Ledney, G D; Madonna, G S; Elliott, T B; Moore, M M; Jackson, W E

1991-10-01

When host antimicrobial defenses are severely compromised by radiation or trauma in conjunction with radiation, death from sepsis results. To evaluate therapies for sepsis in radiation casualties, we developed models of acquired and induced bacterial infections in irradiated and irradiated-wounded mice. Animals were exposed to either a mixed radiation field of equal proportions of neutrons and gamma rays (n/gamma = 1) from a TRIGA reactor or pure gamma rays from 60[Co sources. Skin wounds (15% of total body surface area) were inflicted under methoxyflurane anesthesia 1 h after irradiation. In all mice, wounding after irradiation decreased resistance to infection. Treatments with the immunomodulator synthetic trehalose dicorynomycolate (S-TDCM) before or after mixed neutron-gamma irradiation or gamma irradiation increased survival. Therapy with S-TDCM for mice irradiated with either a mixed field or gamma rays increased resistance to Klebsiella pneumoniae-induced infections. Combined therapy with S-TDCM and ceftriaxone for K. pneumoniae infections in mice exposed to a mixed radiation field or to gamma rays was more effective than single-agent therapy. In all irradiated-wounded mice, single therapy of acquired infections with an antibiotic or S-TDCM did not increase survival. Survival of irradiated-wounded mice after topical application of gentamicin sulfate cream suggested that bacteria colonizing the wound disseminated systemically in untreated irradiated mice, resulting in death from sepsis. In lethal models of acquired infections in irradiated-wounded mice, significant increases in survival were achieved when systemic treatments with S-TDCM or gentamicin were combined with topical treatments of gentamicin cream. Therapies for sepsis in all mice exposed to a mixed field were less effective than in mice exposed to gamma rays. Nonetheless, the data show a principle by which successful therapy may be provided to individuals receiving tissue trauma in conjunction with

In situ observation of triple junction motion during recovery of heavily deformed aluminum

DEFF Research Database (Denmark)

Yu, Tianbo; Hughes, Darcy A.; Hansen, Niels

2015-01-01

-junctions are pinned by deformation-induced interconnecting and lamellar boundaries, which slow down the recovery process and lead to a stop-go migration pattern. This pinning mechanism stabilizes the deformation microstructure, i.e. the structure is stabilized by balancing the driving and pinning forces controlling......Microstructural evolution during in situ annealing of heavily cold-rolled aluminum has been studied by transmission electron microscopy, confirming that an important recovery mechanism is migration of triple junctions formed by three lamellar boundaries (Y-junctions). The migrating Y...

Nice Guys Finish Last: Are People with Higher Tax Morale Taxed more Heavily?

OpenAIRE

Philipp Doerrenberg; Denvil Duncan; Clemens Fuest; Andreas Peichl

2012-01-01

This paper is the first to provide evidence of efficient taxation of groups with heterogeneous levels of 'tax morale'. We set up an optimal income tax model where high tax morale implies a high subjective cost of evading taxes. The model predicts that 'nice guys finish last': groups with higher tax morale will be taxed more heavily, simply because taxing them is less costly. Based on unique cross-country micro data and an IV approach to rule out reverse causality, we find empirical support fo...

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

International Nuclear Information System (INIS)

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

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.

CONTRIBUTION OF HANARO IRRADIATION TECHNOLOGIES TO NATIONAL NUCLEAR R&D

Directory of Open Access Journals (Sweden)

KEE NAM CHOO

2014-08-01

Full Text Available HANARO is a multipurpose research reactor located at the Korea Atomic Energy Research Institute (KAERI. Since the commencement of its operation in 1995, various neutron irradiation facilities, such as rabbit irradiation facilities, fuel test loop (FTL facilities, capsule irradiation facilities, and neutron transmutation doping (NTD facilities, have been developed and actively utilized for various nuclear material irradiation tests requested by users from research institutes, universities, and industries. Most irradiation tests have been related to national R&D relevant to present nuclear power reactors such as the ageing management and safety evaluation of the components. Based on the accumulated experience as well as the sophisticated requirements of users, HANARO has recently supported national R&D projects relevant to new nuclear systems including the System-integrated Modular Advanced Reactor (SMART, research reactors, and future nuclear systems. This paper documents the current state and utilization of irradiation facilities in HANARO, and summarizes ongoing research efforts to deploy advanced irradiation technology.

Radiation safety for operators of gamma irradiation plants

International Nuclear Information System (INIS)

1989-01-01

These notes have been prepared by the UK Panel for Gamma and Electron Irradiation with advice from the HSE (Technology Division and Factory and Agricultural Inspectorate) to assist operators of Gamma irradiation plants to comply with the requirements of the Ionising Radiations Regulations (IRR 1985), and other relevant regulations (see below). The process is currently used for the sterilisation of medical devices and in the treatment of plastics materials etc. The Government has proposed that the process should also be permitted for the treatment of foodstuffs, and these notes will also be relevant to any irradiation plants which may be used in the UK for this purpose. (author)

Quantification of 5-hydroxytryptamine1A receptors in the cerebellum of normal and x-irradiated rats during postnatal development

International Nuclear Information System (INIS)

Matthiessen, L.; Daval, G.; Bailly, Y.; Gozlan, H.; Hamon, M.; Verge, D.

1992-01-01

5-Hydroxytryptamine 1A receptors were studied in rats during the first postnatal month in the normal cerebellum and in the granule cell-deprived cerebellum produced by X-irradiation at postnatal day 5. Quantitative autoradiographic studies on sagittal sections of cerebellar vermis, using [ 125 1]BH-8-MeO-N-PAT as radioligand or specific anti-receptor antibodies, revealed that 5-hydroxytryptamine 1A receptors existed in the molecular/Purkinje cell layer but at variable density from one lobule to another. Thus, in both normal and X-irradiated rats, the posterior lobules were more heavily labelled than the anterior ones, and the density of 5-hydroxytryptamine 1A sites decreased progressively in all the cerebellar folia down to hardly detectable levels at postnatal day 21. However, the intensity of labelling remained higher at postnatal day 8 and postnatal day 12 in X-irradiated rats than in age-paired controls. Measurements of [ 3 H]8-OH-DPAT [8-hydroxy-2-(di-n-propylamino)tetralin] specific binding to membranes from whole cerebellum confirmed that the density of 5-hydroxytryptamine 1A sites per mg membrane protein (B max ) was higher in X-irradiated animals than in age-paired controls. However, on a ''per cerebellum'' basis, no significant difference could be detected between the total number of 5-hydroxytryptamine 1A sites, which progressively increased in both control and X-irradiated animals during the first postnatal month. These results therefore show that 5-hydroxytryptamine 1A receptors are not located on developing granule cells. (author)

Irradiation probe and laboratory for irradiated material evaluation

International Nuclear Information System (INIS)

Smutny, S.; Kupca, L.; Beno, P.; Stubna, M.; Mrva, V.; Chmelo, P.

1975-09-01

The survey and assessment are given of the tasks carried out in the years 1971 to 1975 within the development of methods for structural materials irradiation and of a probe for the irradiation thereof in the A-1 reactor. The programme and implementation of laboratory tests of the irradiation probe are described. In the actual reactor irradiation, the pulse tube length between the pressure governor and the irradiation probe is approximately 20 m, the diameter is 2.2 mm. Temperature reaches 800 degC while the pressure control system operates at 20 degC. The laboratory tests (carried out at 20 degC) showed that the response time of the pressure control system to a stepwise pressure change in the irradiation probe from 0 to 22 at. is 0.5 s. Pressure changes were also studied in the irradiation probe and in the entire system resulting from temperature changes in the irradiation probe. Temperature distribution in the body of the irradiation probe heating furnace was determined. (B.S.)

Chapter 2: Irradiators

Energy Technology Data Exchange (ETDEWEB)

NONE

2018-04-01

The chapter 2 presents the subjects: 1) gamma irradiators which includes: Category-I gamma irradiators (self-contained); Category-II gamma irradiators (panoramic and dry storage); Category-III gamma irradiators (self-contained in water); Category-IV gamma irradiators (panoramic and wet storage); source rack for Category-IV gamma irradiators; product transport system for Category-IV gamma irradiators; radiation shield for gamma irradiators; 2) accelerators which includes: Category-I Accelerators (shielded irradiator); Category-II Accelerators (irradiator inside a shielded room); Irradiation application examples.

Electron beam irradiation effect on GaN HEMT

International Nuclear Information System (INIS)

Lou Yinhong; Guo Hongxia; Zhang Keying; Wang Yuanming; Zhang Fengqi

2011-01-01

In this work, GaN HEMTs (High Electron Mobility Transistor) were irradiated by 0.8 and 1.2 MeV electron beams, and the irradiation effects were investigated. The results show that the device damage caused by 0.8 MeV electrons is more serious than that by 1.2 MeV electrons. Saturation drain current increase and threshold voltage negative shift are due to trapped positive charge from ionization in the AlGaN layer and N, Ga vacancy from non-ionizing energy loss in the GaN layer. Electron traps and trapped positive charges from non-ionizing in the AlGaN layer act as trap-assisted-tunneling centers that increase the gate leakage current.(authors)

Short-channel drain current model for asymmetric heavily / lightly ...

Indian Academy of Sciences (India)

PRADIPTA DUTTA

2017-07-29

Jul 29, 2017 ... (2017) 89:33 ... MS received 25 August 2015; revised 6 March 2017; accepted 6 April 2017; published ..... [18] J P Colinge, J W Park and W Xiong, IEEE Electron. ... devices(Cambridge University Press, Cambridge, 1998).

Effect of gamma irradiation on leakage current in CMOS read-out chips for the ATLAS upgrade silicon strip tracker at the HL-LHC

CERN Document Server

Stucci, Stefania Antonia; Lynn, Dave; Kierstead, James; Kuczewski, Philip; van Nieuwenhuizen, Gerrit J; Rosin, Guy; Tricoli, Alessandro

2017-01-01

The increase of the leakage current of NMOS transistors in detector readout chips in certain 130 nm CMOS technologies during exposure to ionising radiation needs special consideration in the design of detector systems, as this can result in a large increase of the supply current and power dissipation. As part of the R&D; program for the upgrade of the ATLAS inner detector tracker for the High Luminosity upgrade of the LHC at CERN, a dedicated set of irradiations have been carried out with the $^60$Co gamma-ray source at the Brookhaven National Laboratory. Measurements will be presented that characterise the increase in the digital leakage current in the 130 nm-technology ABC130 readout chips. The variation of the current as a function of time and total ionising dose has been studied under various conditions of dose rate, temperature and power applied to the chip. The range of variation of dose rates and temperatures has been set to be close to those expected at the High Luminosity LHC, i.e. in the range 0...

Antecedents, actual situation and prospective of the food irradiation in Mexico

International Nuclear Information System (INIS)

Lopez V, H.; Polo C, G.; Ramirez de Alba, M.; Mayoral G, V.M.

1992-06-01

In this work a synthesis of the history of the food irradiation in Mexico is presented, as well as its current situation. In the same way the foods produced in the country that are susceptible to be irradiated are identified, with object of presenting this process as an alternative method to conserve and to improve the safety of the foods, also showing the potential of the installation of new irradiation plants. (Author)

Proton irradiation of CVD diamond detectors for high-luminosity experiments at the LHC

Science.gov (United States)

Meier, D.; Adam, W.; Bauer, C.; Berdermann, E.; Bergonzo, P.; Bogani, F.; Borchi, E.; Bruzzi, M.; Colledani, C.; Conway, J.; Dabrowski, W.; Delpierre, P.; Deneuville, A.; Dulinski, W.; van Eijk, B.; Fallou, A.; Foulon, F.; Friedl, M.; Jany, C.; Gan, K. K.; Gheeraert, E.; Grigoriev, E.; Hallewell, G.; Hall-Wilton, R.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kania, D.; Kaplon, J.; Kass, R.; Knöpfle, K. T.; Krammer, M.; Manfredi, P. F.; Marshall, R. D.; Mishina, M.; Le Normand, F.; Pan, L. S.; Palmieri, V. G.; Pernegger, H.; Pernicka, M.; Peitz, A.; Pirollo, S.; Pretzl, K.; Re, V.; Riester, J. L.; Roe, S.; Roff, D.; Rudge, A.; Schnetzer, S.; Sciortino, S.; Speziali, V.; Stelzer, H.; Stone, R.; Tapper, R. J.; Tesarek, R.; Thomson, G. B.; Trawick, M.; Trischuk, W.; Turchetta, R.; Walsh, A. M.; Wedenig, R.; Weilhammer, P.; Ziock, H.; Zoeller, M.; RD42 Collaboration

1999-04-01

CVD diamond shows promising properties for use as a position-sensitive detector for experiments in the highest radiation areas at the Large Hadron Collider. In order to study the radiation hardness of diamond we exposed CVD diamond detector samples to 24 Gev/ c and 500 Mev protons up to a fluence of 5×10 15 p/cm 2. We measured the charge collection distance, the average distance electron-hole pairs move apart in an external electric field, and leakage currents before, during, and after irradiation. The charge collection distance remains unchanged up to 1×10 15 p/cm 2 and decreases by ≈40% at 5×10 15 p/cm 2. Leakage currents of diamond samples were below 1 pA before and after irradiation. The particle-induced currents during irradiation correlate well with the proton flux. In contrast to diamond, a silicon diode, which was irradiated for comparison, shows the known large increase in leakage current. We conclude that CVD diamond detectors are radiation hard to 24 GeV/ c and 500 MeV protons up to at least 1×10 15p/cm 2 without signal loss.

Proton irradiation of CVD diamond detectors for high-luminosity experiments at the LHC

International Nuclear Information System (INIS)

Meier, D.; Adam, W.; Bauer, C.; Berdermann, E.; Bergonzo, P.; Bogani, F.; Borchi, E.; Bruzzi, M.; Colledani, C.; Conway, J.; Dabrowski, W.; Delpierre, P.; Deneuville, A.; Dulinski, W.; Eijk, B. van; Fallou, A.; Foulon, F.; Friedl, M.; Jany, C.; Gan, K.K.; Gheeraert, E.; Grigoriev, E.; Hallewell, G.; Hall-Wilton, R.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kania, D.; Kaplon, J.; Kass, R.; Knoepfle, K.T.; Krammer, M.; Manfredi, P.F.; Marshall, R.D.; Mishina, M.; Le Normand, F.; Pan, L.S.; Palmieri, V.G.; Pernegger, H.; Pernicka, M.; Peitz, A.; Pirollo, S.; Pretzl, K.; Re, V.; Riester, J.L.; Roe, S.; Roff, D.; Rudge, A.; Schnetzer, S.; Sciortino, S.; Speziali, V.; Stelzer, H.; Stone, R.; Tapper, R.J.; Tesarek, R.; Thomson, G.B.; Trawick, M.; Trischuk, W.; Turchetta, R.; Walsh, A.M.; Wedenig, R.; Weilhammer, P.; Ziock, H.; Zoeller, M.

1999-01-01

CVD diamond shows promising properties for use as a position-sensitive detector for experiments in the highest radiation areas at the Large Hadron Collider. In order to study the radiation hardness of diamond we exposed CVD diamond detector samples to 24 Gev/c and 500 Mev protons up to a fluence of 5x10 15 p/cm 2 . We measured the charge collection distance, the average distance electron-hole pairs move apart in an external electric field, and leakage currents before, during, and after irradiation. The charge collection distance remains unchanged up to 1x10 15 p/cm 2 and decreases by ∼40% at 5x10 15 p/cm 2 . Leakage currents of diamond samples were below 1 pA before and after irradiation. The particle-induced currents during irradiation correlate well with the proton flux. In contrast to diamond, a silicon diode, which was irradiated for comparison, shows the known large increase in leakage current. We conclude that CVD diamond detectors are radiation hard to 24 GeV/c and 500 MeV protons up to at least 1x10 15 p/cm 2 without signal loss

Quality assurance and irradiation studies on CMS silicon strip sensors

CERN Document Server

Furgeri, Alexander

The high luminosity at the Large Hadron Collider at the European Particle Physics Laboratory CERN in Geneva causes a harsh radiation environment for the detectors. The most inner layers of the tracker are irradiated to an equivalent fluence of 1.6e14 1MeV-neutrons per cmˆ2. The radiation causes damage in the silicon lattice of the sensors. This increases the leakage current and changes the full depletion voltage. Both of these parameters are after irradiation neither stable with time nor with temperatures above 0oC. This thesis presents the changes of the leakage currents, the full depletion voltages, and all strip parameters of the sensors after proton and neutron irradiation. After irradiation annealing studies have been carried out. All observed effects are used to simulate the evolution of full depletion voltage for different annealing times and annealing temperatures in order to keep the power consumption as low as possible. From the observed radiation damage and annealing effects the sensors of the tra...

High total dose proton irradiation effects on silicon NPN rf power transistors

International Nuclear Information System (INIS)

Bharathi, M. N.; Praveen, K. C.; Prakash, A. P. Gnana; Pushpa, N.

2014-01-01

The effects of 3 MeV proton irradiation on the I-V characteristics of NPN rf power transistors were studied in the dose range of 100 Krad to 100 Mrad. The different electrical characteristics like Gummel, current gain and output characteristics were systematically studied before and after irradiation. The recovery in the I-V characteristics of irradiated NPN BJTs were studied by isochronal and isothermal annealing methods

High total dose proton irradiation effects on silicon NPN rf power transistors

Energy Technology Data Exchange (ETDEWEB)

Bharathi, M. N.; Praveen, K. C.; Prakash, A. P. Gnana, E-mail: gnanaprakash@physics.uni-mysore.ac.in [Department of Studies in Physics, University of Mysore, Manasagangotri, Mysore-570006, Karnataka (India); Pushpa, N. [Department of PG Studies in Physics, JSS College, Ooty Road, Mysore-570025, Karnataka (India)

2014-04-24

The effects of 3 MeV proton irradiation on the I-V characteristics of NPN rf power transistors were studied in the dose range of 100 Krad to 100 Mrad. The different electrical characteristics like Gummel, current gain and output characteristics were systematically studied before and after irradiation. The recovery in the I-V characteristics of irradiated NPN BJTs were studied by isochronal and isothermal annealing methods.

Presentation of the CPR ISMIR (Insulators: IRradiation Modelling); Presentation du CPR ISMIR (ISolants: modelisation de l'IRradiation)

Energy Technology Data Exchange (ETDEWEB)

Lozes, G. [CEA Saclay, Dir. de l' Energie Nucleaire (DEN/DSOE), 91 - Gif sur Yvette (France)

2007-07-01

The CPR ISMIR is a CEA-CNRS program on the behaviour of materials submitted to irradiation; it has been begun to support the applied current research programs on the aging of nuclear fuels, the storage and incineration matrices and the future reactors. Its aim is to contribute to scientifically set up the methods for anticipating the behaviour of ceramic materials under irradiation in using the important development of calculation means. Thus have been developed the basic knowledge and the interactions physics and calculation models at pertinent scales have been elaborated. (O.M.)

New JMTR irradiation test plan on fuels and materials

International Nuclear Information System (INIS)

Nakamura, Takehiko; Nishiyama, Yutaka; Chimi, Yasuhiro; Sasajima, Hideo; Ogiyanagi, Jin; Nakamura, Jinichi; Suzuki, Masahide; Kawamura, Hiroshi

2009-01-01

In order to maintain and enhance safety of light water reactors (LWRs) in long-term and up-graded operations, proper understanding of irradiation behavior of fuels and materials is essentially important. Japanese government and the Japan Atomic Energy Agency (JAEA) have decided to refurbish the Japan Materials Testing Reactor (JMTR) and to install new tests rigs, in order to play an active role for solving irradiation related issues on plant aging and high-duty uses of the current LWRs and on development of next-generation reactors. New tests on fuel integrity under simulated abnormal transients and high-duty irradiation conditions are planned in the JMTR. Power ramp tests of newdesign fuel rods will also be performed in the first stage of the program, which is expected to start in year 2011 after refurbishment of the JMTR. Combination of the JMTR tests with simulated reactivity initiated accident tests in the Nuclear Safety Research Reactor (NSRR) and loss of coolant accident tests in hot laboratories would serve as the integrated fuel safety research on the high performance fuels at extended burnups, covering from the normal to the accident conditions, including abnormal transients. For the materials irradiation, fracture toughness of reactor vessel steels and stress corrosion cracking behavior of stainless steels are being studied in addition to basic irradiation behavior of nuclear materials such as hafnium. The irradiation studies would contribute not only to solve the current problems but also to identify possible seeds of troubles and to make proactive responses. (author)

Total lymphoid irradiation and cyclophosphamide conditioning prior to bone marrow transplantation for patients with severe aplastic anemia

International Nuclear Information System (INIS)

Ramsay, N.K.; Kim, T.H.; McGlave, P.; Goldman, A.; Nesbit, M.E. Jr.; Krivit, W.; Woods, W.G.; Kersey, J.H.

1983-01-01

A preparative regimen, consisting of total lymphoid irradiation and cyclophosphamide, was utilized in 40 patients with severe aplastic anemia undergoing allogeneic marrow transplantation. This regimen was successful in decreasing rejection in these previously transfused patients, as only one patient rejected the marrow graft. Twenty-nine of the 40 transplanted patients are surviving from 1.5 to 59 mo, with a median follow-up of 24 mo. The actuarial survival rate for these heavily transfused patients with aplastic anemia is 72% at 2 yr. This preparative regimen is extremely effective in decreasing rejection following transplantation for severe aplastic anemia. Future efforts in this area must be aimed at the elimination of graft-versus-host disease and control of fatal infections

Highly efficient and heavily-doped organic light-emitting devices based on an orange phosphorescent iridium complex

International Nuclear Information System (INIS)

Zhou, Shunliang; Wang, Qi; Li, Ming; Lu, Zhiyun; Yu, Junsheng

2014-01-01

Heavily doped and highly efficient phosphorescent organic light-emitting devices (PhOLEDs) had been fabricated by utilizing an orange iridium complex, bis[2-(3′,5′-di-tert-butylbiphenyl-4-yl)benzothiazolato-N,C 2' ]iridium(III) (acetylacetonate) [(tbpbt) 2 Ir(acac)], as a phosphor. When the doping concentration of [(tbpbt) 2 Ir(acac)] reached as high as 15 wt%, the PhOLEDs exhibited a power efficiency, current efficiency, and external quantum efficiency of 24.5 lm/W, 32.1 cd/A, 15.7%, respectively, implying a promising quenching-resistant characteristics of this novel phosphor. Furthermore, the efficient white PhOLEDs had been obtained by employing (tbpbt) 2 Ir(acac) as a self-host orange emitter, indicating that (tbpbt) 2 Ir(acac) could serve as a promising phosphor to fabricate white organic light-emitting devices with simplified manufacturing process. - Highlights: • Efficient phosphorescent devices were fabricated. • Optimized phosphor doping ratio reached as high as 15 wt%. • The results proved a promising quench-resistant property of the phosphor. • Efficient white devices based on this phosphor as self-host layer had been realized

Highly efficient and heavily-doped organic light-emitting devices based on an orange phosphorescent iridium complex

Energy Technology Data Exchange (ETDEWEB)

Zhou, Shunliang; Wang, Qi [State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054 (China); Li, Ming [College of Chemistry, Sichuan University, Chengdu, 610064 (China); Lu, Zhiyun, E-mail: luzhiyun@scu.edu.cn [College of Chemistry, Sichuan University, Chengdu, 610064 (China); Yu, Junsheng, E-mail: jsyu@uestc.edu.cn [State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054 (China)

2014-10-15

Heavily doped and highly efficient phosphorescent organic light-emitting devices (PhOLEDs) had been fabricated by utilizing an orange iridium complex, bis[2-(3′,5′-di-tert-butylbiphenyl-4-yl)benzothiazolato-N,C{sup 2'}]iridium(III) (acetylacetonate) [(tbpbt){sub 2}Ir(acac)], as a phosphor. When the doping concentration of [(tbpbt){sub 2}Ir(acac)] reached as high as 15 wt%, the PhOLEDs exhibited a power efficiency, current efficiency, and external quantum efficiency of 24.5 lm/W, 32.1 cd/A, 15.7%, respectively, implying a promising quenching-resistant characteristics of this novel phosphor. Furthermore, the efficient white PhOLEDs had been obtained by employing (tbpbt){sub 2}Ir(acac) as a self-host orange emitter, indicating that (tbpbt){sub 2}Ir(acac) could serve as a promising phosphor to fabricate white organic light-emitting devices with simplified manufacturing process. - Highlights: • Efficient phosphorescent devices were fabricated. • Optimized phosphor doping ratio reached as high as 15 wt%. • The results proved a promising quench-resistant property of the phosphor. • Efficient white devices based on this phosphor as self-host layer had been realized.

Food irradiation

International Nuclear Information System (INIS)

Sato, Tomotaro; Aoki, Shohei

1976-01-01

Definition and significance of food irradiation were described. The details of its development and present state were also described. The effect of the irradiation on Irish potatoes, onions, wiener sausages, kamaboko (boiled fish-paste), and mandarin oranges was evaluated; and healthiness of food irradiation was discussed. Studies of the irradiation equipment for Irish potatoes in a large-sized container, and the silo-typed irradiation equipment for rice and wheat were mentioned. Shihoro RI center in Hokkaido which was put to practical use for the irradiation of Irish potatoes was introduced. The state of permission of food irradiation in foreign countries in 1975 was introduced. As a view of the food irradiation in the future, its utilization for the prevention of epidemics due to imported foods was mentioned. (Serizawa, K.)

High-current heavy-ion accelerator system and its application to material modification

International Nuclear Information System (INIS)

Kishimoto, Naoki; Takeda, Yoshihiko; Lee, C.G.; Umeda, Naoki; Okubo, Nariaki; Iwamoto, Eiji

2001-01-01

A high-current heavy-ion accelerator system has been developed to realize intense particle fluxes for material modification. The facility of a tandem accelerator attained 1 mA-class ion current both for negative low-energy ions and positive high-energy ions. The negative ion source of the key device is of the plasma-sputter type, equipped with mutli-cusp magnets and Cs supply. The intense negative ions are either directly used for material irradiation at 60 keV or further accelerated up to 6 MeV after charge transformation. Application of negative ions, which alleviates surface charging, enables us to conduct low-energy high-current irradiation on insulating substrates. Since positive ions above the MeV range are irrelevant for Coulomb repulsion, the facility as a whole meets the needs of high-current irradiation onto insulators over a wide energy range. Application of high flux ions provides technological merits not only for efficient implantation but also for essentially different material kinetics, which may become an important tool of material modification. Other advantages of the system are co-irradiation by intense laser and in-situ detection of kinetic processes. For examples of material modifications, we present nanoparticle fabrication in insulators, and synergistic phenomena by co-irradiation due to ions and photons. (author)

Food irradiation

Energy Technology Data Exchange (ETDEWEB)

Gruenewald, T

1985-01-01

Food irradiation has become a matter of topical interest also in the Federal Republic of Germany following applications for exemptions concerning irradiation tests of spices. After risks to human health by irradiation doses up to a level sufficient for product pasteurization were excluded, irradiation now offers a method suitable primarily for the disinfestation of fruit and decontamination of frozen and dried food. Codex Alimentarius standards which refer also to supervision and dosimetry have been established; they should be adopted as national law. However, in the majority of cases where individual countries including EC member-countries so far permitted food irradiation, these standards were not yet used. Approved irradiation technique for industrial use is available. Several industrial food irradiation plants, partly working also on a contractual basis, are already in operation in various countries. Consumer response still is largely unknown; since irradiated food is labelled, consumption of irradiated food will be decided upon by consumers.

Fast wave current drive technology development at ORNL

International Nuclear Information System (INIS)

Baity, F.W.; Batchelor, D.B.; Goulding, R.H.; Hoffman, D.J.; Jaeger, E.F.; Ryan, P.M.; deGrassie, J.S.; Petty, C.C.; Pinsker, R.I.; Prater, R.

1993-01-01

The technology required for fast wave current drive (FWCD) systems is discussed. Experiments are underway on DIII-D, JET, and elsewhere. Antennas for FWCD draw heavily upon the experience gained in the design of ICRF heating systems with the additional requirement of launching a directional wave spectrum. Through collaborations with DIII-D, JET, and Tore Supra rapid progress is being made in the demonstration of the physics and technology of FWCD needed for TPX and ITER

Fast wave current drive technology development at ORNL

International Nuclear Information System (INIS)

Baity, F.W.; Batchelor, D.B.; Goulding, R.H.

1994-01-01

The technology required for fast wave current drive (FWCD) systems is discussed. Experiments are underway on DIII-D, JET, and elsewhere. Antennas for FWCD draw heavily upon the experience gained in the design of ICRF heating systems with the additional requirement of launching a directional wave spectrum. Through collaborations with DIII-D, JET, and Tore Supra rapid progress is being made in the demonstration of the physics and technology of FWCD needed for TPX and ITER. (author)

Fusion neutron irradiation of Ni-Si alloys at high temperature*1

Science.gov (United States)

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

1988-07-01

Two Ni-4% Si alloys, with different cold work levels, have been irradiated with 14-MeV fusion neutrons at 623 K, and their Curie temperatures have been 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 6-7% 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 6-7% for the fusion neutron irradiated sample.

Charge collection in Si detectors irradiated in situ at superfluid helium temperature

Science.gov (United States)

Verbitskaya, Elena; Eremin, Vladimir; Zabrodskii, Andrei; Dehning, Bernd; Kurfürst, Christoph; Sapinski, Mariusz; Bartosik, Marcin R.; Egorov, Nicolai; Härkönen, Jaakko

2015-10-01

Silicon and diamond detectors operated in a superfluid helium bath are currently being considered for the upgrade of the LHC beam loss monitoring system. The detectors would be installed in immediate proximity of the superconducting coils of the triplet magnets. We present here the results of the in situ irradiation test for silicon detectors using 23 GeV protons while keeping the detectors at a temperature of 1.9 K. Red laser (630 nm) Transient Current Technique and DC current measurements were used to study the pulse response and collected charge for silicon detectors irradiated to a maximum radiation fluence of 1×1016 p/cm2. The dependence between collected charge and irradiation fluence was parameterized using the Hecht equation and assumption of a uniform electric field distribution. The collected charge was found to degrade with particle fluence for both bias polarities. We observed that the main factor responsible for this degradation was related to trapping of holes on the donor-type radiation-induced defects. In contrast to expectations, along with formation of donors, acceptor-type defects (electron traps) are introduced into the silicon bulk. This suggests that the current models describing charge collection in irradiated silicon detectors require an extension for taking into account trapping at low temperatures with a contribution of shallow levels. New in situ irradiation tests are needed and planned now to extend statistics of the results and gain a deeper insight into the physics of low temperature detector operation in harsh radiation environment.

Cytogenetic investigations of persons exposed to professional chronic low-dose irradiation

International Nuclear Information System (INIS)

Rangelov, V.; Mitev, L.; Petrunov, P.; Vesselinova, L.

2005-01-01

The problem of long term influence of low-doses occupational irradiation is connected with the real assessment of their consequences. The current cytogenetic investigations were done on persons working under occupational chronic external partial irradiation. Accumulated doses of external irradiation are surveyed. Data give ground for suggestion about the relationship between accumulated dose and chromosomal aberrations. The additional damage factors (diagnostic investigations, chemical substances, tobacco addict) have done the more significant influence upon aberrations appearance increasing

Enhanced vortex pinning and critical current density in proton-irradiated YBa2Cu3O7-δ thin films

International Nuclear Information System (INIS)

Venturini, E.L.; Siegal, M.P.; White, A.E.; Hou, S.Y.; Phillips, J.M.

1993-01-01

The appropriate fluence of 2.0 MeV H + ions has been shown previously to enhance the critical current density J c by a factor of two at a magnetic field of 0.9 tesla in 1,000 angstrom thick epitaxial films of YBa 2 Cu 3 O 7-δ grown by the ex situ BaF 2 process. The as-grown films exhibit single crystal-like behavior in both atomic ordering and J c versus temperature and magnetic field. TRIM simulations suggest that H + irradiation generates mainly point defects throughout the crystal structure. The authors show here that such defects result in an even greater enhancement of J c for fields above 1 tesla plus a significant increase in the apparent vortex pinning potential deduced from magnetization relaxation data

Enhanced vortex pinning and critical current density in proton-irradiated YBa2Cu3O(7-delta) thin films

Science.gov (United States)

Venturini, E. L.; Siegal, M. P.; White, A. E.; Hou, S. Y.; Phillips, J. M.

1992-11-01

The appropriate fluence of 2.0 MeV H(sup +) ions has been shown previously to enhance the critical current density J(sub c) by a factor of two at a magnetic field of 0.9 tesla in 1000 (Angstrom) thick epitaxial films of YBa(2)Cu(3)O(7-delta) grown by the ex situ BaF2 process. The as-grown films exhibit single crystal-like behavior in both atomic ordering and J(sub c) versus temperature and magnetic field. TRIM simulations suggest that H(sup +) irradiation generates mainly point defects throughout the crystal structure. We show here that such defects produce both a large enhancement of J(sub c) for fields above 1 tesla and a significant increase in the apparent vortex pinning potential deduced from magnetization relaxation data.

The nature of the torus in the heavily obscured AGN Markarian 3: an X-ray study

DEFF Research Database (Denmark)

Guainazzi, M.; Risaliti, G.; Awaki, H.

2016-01-01

In this paper, we report the results of an X-ray monitoring campaign on the heavily obscured Seyfert galaxy, Markarian 3, carried out between the fall of 2014 and the spring of 2015 with NuSTAR, Suzaku and XMM–Newton. The hard X-ray spectrum of Markarian 3 is variable on all the time-scales probe...

Performance of silicon pad detectors after mixed irradiations with neutrons and fast charged hadrons

Energy Technology Data Exchange (ETDEWEB)

Kramberger, G. [Jozef Stefan Institute, Department of Physics, University of Ljubljana, Jamova 39, SI-1000 Ljubljana (Slovenia)], E-mail: Gregor.Kramberger@ijs.si; Cindro, V.; Dolenc, I.; Mandic, I.; Mikuz, M.; Zavrtanik, M. [Jozef Stefan Institute, Department of Physics, University of Ljubljana, Jamova 39, SI-1000 Ljubljana (Slovenia)

2009-10-11

A large set of silicon pad detectors produced on MCz and FZ wafer of p- and n-type was irradiated in two steps, first by fast charged hadrons followed by reactor neutrons. In this way the irradiations resemble the real irradiation fields at LHC. After irradiations controlled annealing started in steps during which the evolution of full depletion voltage, leakage current and charge collection efficiency was monitored. The damage introduced by different irradiation particles was found to be additive. The most striking consequence of that is a decrease of the full depletion voltage for n-type MCz detectors after additional neutron irradiation. This confirms that effective donors introduced by charged hadron irradiation are compensated by acceptors from neutron irradiation.

Performance of silicon pad detectors after mixed irradiations with neutrons and fast charged hadrons

International Nuclear Information System (INIS)

Kramberger, G.; Cindro, V.; Dolenc, I.; Mandic, I.; Mikuz, M.; Zavrtanik, M.

2009-01-01

A large set of silicon pad detectors produced on MCz and FZ wafer of p- and n-type was irradiated in two steps, first by fast charged hadrons followed by reactor neutrons. In this way the irradiations resemble the real irradiation fields at LHC. After irradiations controlled annealing started in steps during which the evolution of full depletion voltage, leakage current and charge collection efficiency was monitored. The damage introduced by different irradiation particles was found to be additive. The most striking consequence of that is a decrease of the full depletion voltage for n-type MCz detectors after additional neutron irradiation. This confirms that effective donors introduced by charged hadron irradiation are compensated by acceptors from neutron irradiation.

Low frequency alternating current conduction and dielectric relaxation in polypyrrole irradiated with 100 MeV swift heavy ions of silver (Ag8+)

International Nuclear Information System (INIS)

Kaur, Amarjeet; Dhillon, Anju; Avasthi, D.K.

2013-01-01

Polypyrrole (PPY) films were prepared by electrochemical polymerization technique. The fully undoped samples were irradiated with different radiation fluences ranging from 10 10 to 10 12 ions cm −2 of 100 MeV silver (Ag 8+ ) ions. The temperature dependence of ac conductivity [σ m (ω)], dielectric constant (ε′) and dielectric loss (ε′′) of both irradiated as well as unirradiated samples have been investigated in 77–300 K. There exists typical Debye type dispersion. Giant increase in dielectric constant has been observed for irradiated samples which is attributed to polaronic defects produced during irradiation. - Graphical abstract: Display Omitted - Highlights: • Polypyrrole samples were prepared by electrochemical technique. • The fully undoped samples were irradiated with 100 MeV silver (Ag 8+ ) ions. • Giant increase in dielectric constant in irradiated samples is observed. • Dielectric behaviour is attributed to polaronic defects produced during irradiation

Present status and prospects of food irradiation in France

International Nuclear Information System (INIS)

Laizier, J.

1985-09-01

Following the conclusions of the JEFCI (Joint FAO/IAEA/WHO Expert Committee on whole someness of Irradiated Food), CEA (French Atomic Energy Commission) was required by the regulatory committees, in 1981-82, to present a white book on the whole someness of irradiated foods. Following the approval of this white book it was decided to not modify hastily the current regulation of 1970; but to lighten the content of the file of request for authorization by removing its part related to toxicological evidences. This liberalization of procedure has encouraged industrial projects. A large effort of development is initiated and taken in charge locally. The CEA has very important responsabilities in this national effort of development of food irradiation. Three new designs for gamma industrial irradiators were recently improved in France specifically in view of food irradiation, beside the other more conventional designs of carrier and pallet irradiators, already available and well known. The presently available accelerators are not well fitted to food irradiation; the penetration of electrons which are produced is not high enough for food products. A french company, CGR-MeV, recently developed a linear accelerator of 10 MeV and 10 Kw, which appears very attractive

Quantification of 5-hydroxytryptamine[sub 1A] receptors in the cerebellum of normal and x-irradiated rats during postnatal development

Energy Technology Data Exchange (ETDEWEB)

Matthiessen, L; Daval, G; Bailly, Y [Pierre et Marie Curie Univ., Paris (France). Centre National de la Recherche Scientifique, UA; Gozlan, H; Hamon, M; Verge, D [INSERM, Paris (France). Lab. de Neurobiologie Cellulaire et Fonctionnelle

1992-11-01

5-Hydroxytryptamine[sub 1A] receptors were studied in rats during the first postnatal month in the normal cerebellum and in the granule cell-deprived cerebellum produced by X-irradiation at postnatal day 5. Quantitative autoradiographic studies on sagittal sections of cerebellar vermis, using [[sup 125]1]BH-8-MeO-N-PAT as radioligand or specific anti-receptor antibodies, revealed that 5-hydroxytryptamine[sub 1A] receptors existed in the molecular/Purkinje cell layer but at variable density from one lobule to another. Thus, in both normal and X-irradiated rats, the posterior lobules were more heavily labelled than the anterior ones, and the density of 5-hydroxytryptamine[sub 1A] sites decreased progressively in all the cerebellar folia down to hardly detectable levels at postnatal day 21. However, the intensity of labelling remained higher at postnatal day 8 and postnatal day 12 in X-irradiated rats than in age-paired controls. Measurements of [[sup 3]H]8-OH-DPAT [8-hydroxy-2-(di-n-propylamino)tetralin] specific binding to membranes from whole cerebellum confirmed that the density of 5-hydroxytryptamine[sub 1A] sites per mg membrane protein (B[sub max]) was higher in X-irradiated animals than in age-paired controls. However, on a ''per cerebellum'' basis, no significant difference could be detected between the total number of 5-hydroxytryptamine[sub 1A] sites, which progressively increased in both control and X-irradiated animals during the first postnatal month. These results therefore show that 5-hydroxytryptamine[sub 1A] receptors are not located on developing granule cells. (author).

Proton Irradiation of CVD Diamond Detectors for High Luminosity Experiments at the LHC

CERN Document Server

Meier, D; Bauer, C; Berdermann, E; Bergonzo, P; Bogani, F; Borchi, E; Bruzzi, Mara; Colledani, C; Conway, J; Dabrowski, W; Delpierre, P A; Deneuville, A; Dulinski, W; van Eijk, B; Fallou, A; Foulon, F; Friedl, M; Gan, K K; Gheeraert, E; Grigoriev, E A; Hallewell, G D; Hall-Wilton, R; Han, S; Hartjes, F G; Hrubec, Josef; Husson, D; Jany, C; Kagan, H; Kania, D R; Kaplon, J; Kass, R; Knöpfle, K T; Krammer, Manfred; Manfredi, P F; Marshall, R D; Mishina, M; Le Normand, F; Pan, L S; Palmieri, V G; Pernegger, H; Pernicka, Manfred; Peitz, A; Pirollo, S; Pretzl, Klaus P; Re, V; Riester, J L; Roe, S; Roff, D G; Rudge, A; Schnetzer, S R; Sciortino, S; Speziali, V; Stelzer, H; Stone, R; Tapper, R J; Tesarek, R J; Thomson, G B; Trawick, M L; Trischuk, W; Turchetta, R; Walsh, A M; Wedenig, R; Weilhammer, Peter; Ziock, H J; Zöller, M

1999-01-01

CVD diamond shows promising properties for use as a position sensitive detector for experiments in the highest radiation areas at the Large Hadron Collider. In order to study the radiation hardn ess of diamond we exposed CVD diamond detector samples to 24~GeV/$c$ and 500~MeV protons up to a fluence of $5\\times 10^{15}~p/{\\rm cm^2}$. We measured the charge collection distance, the ave rage distance electron hole pairs move apart in an external electric field, and leakage currents before, during, and after irradiation. The charge collection distance remains unchanged up to $1\\ times 10^{15}~p/{\\rm cm^2}$ and decreases by $\\approx$40~\\% at $5\\times 10^{15}~p/{\\rm cm^2}$. Leakage currents of diamond samples were below 1~pA before and after irradiation. The particle indu ced currents during irradiation correlate well with the proton flux. In contrast to diamond, a silicon diode, which was irradiated for comparison, shows the known large increase in leakage curren t. We conclude that CVD diamond detectors are radia...

Trends of irradiated foods in Japan and the world

International Nuclear Information System (INIS)

Ito, Hitoshi

1987-01-01

The present report describes the current situation involving irradiated foods in Japan and other countries. The technique that uses radiations for such purposes as sterilizing foods or increasing their storage life is generally called food irradiation. Data on the increase in storage life, optimum dose for various marine products, sterilization of seasonings and changes in vitamin content are presented and discussed. Evaluation of the wholesomeness of foods requires analysis of induced radioactivity, toxic substances, carcinogenic substances, destruction of nutritious substances and hereditary effects. Results of such analyses are cited, indicating that food irradiation can be performed without significant deterioration in the wholesomeness of foods. In Japan, a council for food irradiation research was established in 1965 and the Atomic Energy Commission started a special research project in 1967. Some advantages and disadvantages of food irradiation were identified by the project and other studies made by various research institutes. In the world, about 20 percent of crops are lost after harvesting due to harmful insects or rotting. It is expected that irradiation will be effective for reducing the loss. (Nogami, K.)

A 20 keV electron gun system for the electron irradiation experiments

International Nuclear Information System (INIS)

Mahapatra, S.K.; Dhole, S.D.; Bhoraskar, V.N.

2005-01-01

An electron gun consisting of cathode, focusing electrode, control electrode and anode has been designed and fabricated for the electron irradiation experiments. This electron gun can provide electrons of any energy over the range 1-20 keV, with current upto 50 μA. This electron gun and a Faraday cup are mounted in the cylindrical chamber. The samples are fixed on the Faraday cup and irradiated with electrons at a pressure ∼10 -7 mbar. The special features of this electron gun system are that, at any electron energy above 1 keV, the electron beam diameter can be varied from 5 to 120 mm on the Faraday cup mounted at a distance of 200 mm from the anode in the chamber. The variation in the electron current over the beam spot of 120 mm diameter is less than 15% and the beam current stability is better than 5%. This system is being used for studying the irradiation effects of 1-20 keV energy electrons on the space quality materials in which the irradiation time may vary from a few tens of seconds to hours

A 20 keV electron gun system for the electron irradiation experiments

Energy Technology Data Exchange (ETDEWEB)

Mahapatra, S.K. [Department of Physics, University of Pune, Pune 411007 (India); Dhole, S.D. [Department of Physics, University of Pune, Pune 411007 (India); Bhoraskar, V.N. [Department of Physics, University of Pune, Pune 411007 (India)]. E-mail: vnb@physics.unipune.ernet.in

2005-01-01

An electron gun consisting of cathode, focusing electrode, control electrode and anode has been designed and fabricated for the electron irradiation experiments. This electron gun can provide electrons of any energy over the range 1-20 keV, with current upto 50 {mu}A. This electron gun and a Faraday cup are mounted in the cylindrical chamber. The samples are fixed on the Faraday cup and irradiated with electrons at a pressure {approx}10{sup -7} mbar. The special features of this electron gun system are that, at any electron energy above 1 keV, the electron beam diameter can be varied from 5 to 120 mm on the Faraday cup mounted at a distance of 200 mm from the anode in the chamber. The variation in the electron current over the beam spot of 120 mm diameter is less than 15% and the beam current stability is better than 5%. This system is being used for studying the irradiation effects of 1-20 keV energy electrons on the space quality materials in which the irradiation time may vary from a few tens of seconds to hours.

A Study on Recovery from Potentially Lethal Damage induced by γ-Irradiation in Plateau-phase Vero Cells in vitro

International Nuclear Information System (INIS)

Kim, Il Han; Choi, Eun Kyung; Ha, Sung Whan; Park, Charn Il; Cha, Chang Yong

1988-01-01

Recovery from potentially lethal damage (PLDR) after irradiation was studied in plateau-phase culture of Vero cells in vitro. Unfed plateau-phase cells were irradiated with dose of 1 to 9 Gy using Cs-137 irradiator. Cells then were incubated again and left in situ for 0, 1, 2, 3, 4, 5, 6 and 24 hours and then were trypsinized, explanted, and subcultured in fresh RPMI-1640 media containing 0.33% agar. Cell survival was measured by colony forming ability. An adequate number of heavily irradiated Vero cells were added as feeder cells to make the total cell number constant in every culture dish. As the postirradiation in situ incubation time increased, surviving fraction increased saturation level at 2 to 4 hours after in situ incubation. As the radiation dose increased, the rate of PLDR also increased. In analysis of cell survival curve fitted to the linear-quadratic model, the linear inactivation coefficient (a) decreased largely and reached nearly to zero but the quadratic inactivation coefficient (b) increased minimally by increment of postirradiation in situ incubation time. So PLDR mainly affected the damage expressed as a. In the multitarget model, significant change was not obtained in D0 but in Dq. Therefore, shoulder region in cell survival curve was mainly affected by PLDR and terminal slope was not influenced at all. And dose-modifying factor by PLDR was relatively higher in shoulder region, that is, in low dose area below 3 Gy

Food irradiation

International Nuclear Information System (INIS)

Lindqvist, H.

1996-01-01

This paper is a review of food irradiation and lists plants for food irradiation in the world. Possible applications for irradiation are discussed, and changes induced in food from radiation, nutritional as well as organoleptic, are reviewed. Possible toxicological risks with irradiated food and risks from alternative methods for treatment are also brought up. Ways to analyze weather food has been irradiated or not are presented. 8 refs

Irradiation testing of coated particle fuel at Hanaro

International Nuclear Information System (INIS)

Goo Kim, Bong; Sung Cho, Moo; Kim, Yong Wan

2014-01-01

TRISO-coated particle fuel is developing to support development of VHTR in Korea. From August 2013, the first irradiation testing of coated particle fuel was begun to demonstrate and qualify TRISO fuel for use in VHTR in the HANARO at KAERI. This experiment is currently undergoing under the atmosphere of a mixed inert gas without on-line temperature monitoring and control combined with on-line fission product monitoring of the sweep gas. The irradiation device contains two test rods, one contains nine fuel compacts and the other five compacts and eight graphite specimens. Each compact has 263 coated particles. After a peak burn-up of about 4 at% and a peak fast neutron fluence of about 1.7 x 10 21 n/cm 2 , PIE will be carried out at KAERI's Irradiated Material Examination Facility. This paper is described characteristics of coated particle fuel, the design of test rod and irradiation device for coated particle fuel, discusses the technical results for irradiation testing at HANARO. (authors)

The materials irradiation experiment for testing plasma facing materials at fusion relevant conditions

Energy Technology Data Exchange (ETDEWEB)

Garrison, L. M., E-mail: garrisonlm@ornl.gov; Egle, B. J. [Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, Tennessee 37831 (United States); Fusion Technology Institute, University of Wisconsin-Madison, 1500 Engineering Drive, Madison, Wisconsin 53706 (United States); Zenobia, S. J.; Kulcinski, G. L.; Santarius, J. F. [Fusion Technology Institute, University of Wisconsin-Madison, 1500 Engineering Drive, Madison, Wisconsin 53706 (United States)

2016-08-15

The Materials Irradiation Experiment (MITE-E) was constructed at the University of Wisconsin-Madison Inertial Electrostatic Confinement Laboratory to test materials for potential use as plasma-facing materials (PFMs) in fusion reactors. PFMs in fusion reactors will be bombarded with x-rays, neutrons, and ions of hydrogen and helium. More needs to be understood about the interactions between the plasma and the materials to validate their use for fusion reactors. The MITE-E simulates some of the fusion reactor conditions by holding samples at temperatures up to 1000 °C while irradiating them with helium or deuterium ions with energies from 10 to 150 keV. The ion gun can irradiate the samples with ion currents of 20 μA–500 μA; the typical current used is 72 μA, which is an average flux of 9 × 10{sup 14} ions/(cm{sup 2} s). The ion gun uses electrostatic lenses to extract and shape the ion beam. A variable power (1-20 W), steady-state, Nd:YAG laser provides additional heating to maintain a constant sample temperature during irradiations. The ion beam current reaching the sample is directly measured and monitored in real-time during irradiations. The ion beam profile has been investigated using a copper sample sputtering experiment. The MITE-E has successfully been used to irradiate polycrystalline and single crystal tungsten samples with helium ions and will continue to be a source of important data for plasma interactions with materials.

Bias dependent charge trapping in MOSFETs during 1 and 6 MeV electron irradiation

Energy Technology Data Exchange (ETDEWEB)

Shinde, N.S. [Department of Chemical Engineering, Mie University, 5148507 (Japan); Kulkarni, V.R.; Mathakari, N.L.; Bhoraskar, V.N. [Department of Physics, Univeristy of Pune, Pune 411007 (India); Dhole, S.D. [Department of Physics, Univeristy of Pune, Pune 411007 (India)], E-mail: sanjay@physics.unipune.ernet.in

2008-06-15

To study irradiation-induced charge trapping in SiO{sub 2} and around the SiO{sub 2}-Si interface, depletion n-MOSFETs (metal-oxide-semiconductor field effect transistor) were used. The devices were gate biased during 1 and 6 MeV pulsed electron irradiation. The I{sub D}-V{sub DS} (drain current versus drain voltage) and I{sub D}-V{sub GS} (drain current versus gate voltage) characteristics were measured before and after irradiation. The shift in threshold voltage {delta}V{sub T} (difference in threshold voltage V{sub T} before and after irradiation) exhibited trends depending on the applied gate bias during 1 MeV electron irradiation. This behavior can be associated to the contribution of irradiation-induced negative charge {delta}N{sub IT} buildup around the SiO{sub 2}-Si interface to {delta}V{sub T}, which is sensitive to the electron tunneling from the substrates. However, only weak gate bias dependence was observed in 6 MeV electron irradiated devices. Independent of the energy loss and applied bias, the positive oxide trapped charge {delta}N{sub OT} is marginal and can be associated to thin and good quality of SiO{sub 2}. These results are explained using screening of free and acceptor states by the applied bias during irradiation, thereby reducing the total irradiation-induced charges.

Advanced solar irradiances applied to satellite and ionospheric operational systems

Science.gov (United States)

Tobiska, W. Kent; Schunk, Robert; Eccles, Vince; Bouwer, Dave

Satellite and ionospheric operational systems require solar irradiances in a variety of time scales and spectral formats. We describe the development of a system using operational grade solar irradiances that are applied to empirical thermospheric density models and physics-based ionospheric models used by operational systems that require a space weather characterization. The SOLAR2000 (S2K) and SOLARFLARE (SFLR) models developed by Space Environment Technologies (SET) provide solar irradiances from the soft X-rays (XUV) through the Far Ultraviolet (FUV) spectrum. The irradiances are provided as integrated indices for the JB2006 empirical atmosphere density models and as line/band spectral irradiances for the physics-based Ionosphere Forecast Model (IFM) developed by the Space Environment Corporation (SEC). We describe the integration of these irradiances in historical, current epoch, and forecast modes through the Communication Alert and Prediction System (CAPS). CAPS provides real-time and forecast HF radio availability for global and regional users and global total electron content (TEC) conditions.

Detecting irradiation of seeds using microgel electrophoresis (a collaborative trial)

International Nuclear Information System (INIS)

Cerda, H.; Haine, H.E.; Jones, J.L.

1995-06-01

Preservation of certain foods by irradiation is permitted in the United Kingdom. However, all irradiated foods must be labelled as such, to ensure consumer choice. To help enforce labelling, a variety of methods have been developed for distinguishing between irradiated and non-irradiated foods. In preliminary trials, microgel electrophoresis -a simple method of assessing DNA damage - has shown considerable promise in this respect. This report describes microgel electrophoresis, and details results obtained in a blind trial carried out in collaboration with the Swedish University of Agricultural Sciences. Microgel electrophoresis facilitates analysis of the leakage of DNA from cells extracted from food material. In irradiated samples, the DNA is fragmented and will leak from cells in an electric current. This leakage can be seen as a 'comet' when the stained gel is viewed with a microscope. The size and shape of the comet can be used to estimate the irradiation dose administered to the sample. In non-irradiated samples the DNA is less fragmented, will tend not to leak from the cells and will not form a comet. (author)

Irradiation creep lifetime analysis on first wall structure materials for CFETR

Energy Technology Data Exchange (ETDEWEB)

Ma, Bing; Peng, Lei, E-mail: penglei@ustc.edu.cn; Zhang, Xiansheng; Shi, Jingyi; Zhan, Jie

2017-05-15

Fusion reactor first wall services on the conditions of high surface heat flux and intense neutron irradiation. For China Fusion Engineering Test Reactor (CFETR) with high duty time factor, it is important to analyze the irradiation effect on the creep lifetime of the main candidate structure materials for first wall, i.e. ferritic/martensitic steel, austenite steel and oxide dispersion strengthened steel. The allowable irradiation creep lifetime was evaluated with Larson-Miller Parameter (LMP) model and finite element method. The results show that the allowable irradiation creep lifetime decreases with increasing of surface heat flux, first wall thickness and inlet coolant temperature. For the current CFETR conceptual design, the lifetime is not limited by thermal creep or irradiation creep, which indicated the room for design parameters optimization.

Near-Field Imaging of Free Carriers in ZnO Nanowires with a Scanning Probe Tip Made of Heavily Doped Germanium

Science.gov (United States)

Sakat, Emilie; Giliberti, Valeria; Bollani, Monica; Notargiacomo, Andrea; Pea, Marialilia; Finazzi, Marco; Pellegrini, Giovanni; Hugonin, Jean-Paul; Weber-Bargioni, Alexander; Melli, Mauro; Sassolini, Simone; Cabrini, Stefano; Biagioni, Paolo; Ortolani, Michele; Baldassarre, Leonetta

2017-11-01

A novel scanning probe tip made of heavily doped semiconductor is fabricated and used instead of standard gold-coated tips in infrared scattering-type near-field microscopy. Midinfrared near-field microscopy experiments are conducted on ZnO nanowires with a lateral resolution better than 100 nm, using tips made of heavily electron-doped germanium with a plasma frequency in the midinfrared (plasma wavelength of 9.5 μ m ). Nanowires embedded in a dielectric matrix are imaged at two wavelengths, 11.3 and 8.0 μ m , above and below the plasma wavelength of the tips. An opposite sign of the imaging contrasts between the nanowire and the dielectric matrix is observed at the two infrared wavelengths, indicating a clear role of the free-electron plasma in the heavily doped germanium tip in building the imaging contrast. Electromagnetic simulations with a multispherical dipole model accounting for the finite size of the tip are well consistent with the experiments. By comparison of the simulated and measured imaging contrasts, an estimate for the local free-carrier density in the investigated ZnO nanowires in the low 1019 cm-3 range is retrieved. The results are benchmarked against the scattering intensity and phase maps obtained on the same sample with a gold-coated probe tip in pseudoheterodyne detection mode.

Accumulation and dissipation of positive charges induced on a PMMA build-up cap of an ionisation chamber by 60Co gamma-ray irradiation

International Nuclear Information System (INIS)

Morishita, Y.; Takata, N.

2013-01-01

The signal current from an ionisation chamber with a PMMA build-up cap decreases with irradiation time due to electric fields produced by positive charges induced on the cap. In the present study, it was confirmed that the signal current decreases faster for irradiation using narrower 60 Co gamma-ray beams. This is because the number of secondary electrons that are emitted from surrounding materials and penetrate the build-up cap is smaller in a narrower gamma-ray beam, so that fewer positive charges are neutralised. The ionisation chamber was first subjected to continuous gamma-ray irradiation for 24 h, following which it was irradiated with shorter periodic gamma-ray bursts while measuring the current signal. This allowed the coefficients of positive charge accumulation and dissipation to be determined. It was found that the dissipation coefficient has a large constant value during gamma-ray irradiation and decreases asymptotically to a small value after irradiation is stopped. From the coefficients, the minimum signal current was calculated, which is the value when accumulation and dissipation balance each other under continuous irradiation. The time required for the signal current to recover following irradiation was also calculated. (authors)

Current enhancement in crystalline silicon photovoltaic by low-cost nickel silicide back contact

KAUST Repository

Bahabry, R. R.; Gumus, A.; Kutbee, A. T.; Wehbe, N.; Ahmed, S. M.; Ghoneim, M. T.; Lee, K. -T.; Rogers, J. A.; Hussain, M. M.

2016-01-01

We report short circuit current (Jsc) enhancement in crystalline silicon (C-Si) photovoltaic (PV) using low-cost Ohmic contact engineering by integration of Nickel mono-silicide (NiSi) for back contact metallization as an alternative to the status quo of using expensive screen printed silver (Ag). We show 2.6 mA/cm2 enhancement in the short circuit current (Jsc) and 1.2 % increment in the efficiency by improving the current collection due to the low specific contact resistance of the NiSi on the heavily Boron (B) doped Silicon (Si) interface.

Current enhancement in crystalline silicon photovoltaic by low-cost nickel silicide back contact

KAUST Repository

Bahabry, R. R.

2016-11-30

We report short circuit current (Jsc) enhancement in crystalline silicon (C-Si) photovoltaic (PV) using low-cost Ohmic contact engineering by integration of Nickel mono-silicide (NiSi) for back contact metallization as an alternative to the status quo of using expensive screen printed silver (Ag). We show 2.6 mA/cm2 enhancement in the short circuit current (Jsc) and 1.2 % increment in the efficiency by improving the current collection due to the low specific contact resistance of the NiSi on the heavily Boron (B) doped Silicon (Si) interface.

High-energy and high-fluence proton irradiation effects in silicon solar cells

International Nuclear Information System (INIS)

Yamaguchi, M.; Taylor, S.J.; Yang, M.; Matsuda, S.; Kawasaki, O.; Hisamatsu, T.

1996-01-01

We have examined proton irradiation damage in high-energy (1 endash 10 MeV) and high-fluence (approx-gt 10 13 cm -2 ) Si n + -p-p + structure space solar cells. Radiation testing has revealed an anomalous increase in short-circuit current I sc followed by an abrupt decrease and cell failure, induced by high-fluence proton irradiation. We propose a model to explain these phenomena by expressing the change in carrier concentration p of the base region as a function of the proton fluence in addition to the well-known model where the short-circuit current is decreased by minority-carrier lifetime reduction after irradiation. The reduction in carrier concentration due to majority-carrier trapping by radiation-induced defects has two effects. First, broadening of the depletion layer increases both the generation endash recombination current and also the contribution of the photocurrent generated in this region to the total photocurrent. Second, the resistivity of the base layer is increased, resulting in the abrupt decrease in the short circuit current and failure of the solar cells. copyright 1996 American Institute of Physics

Ionization versus displacement damage effects in proton irradiated CMOS sensors manufactured in deep submicron process

International Nuclear Information System (INIS)

Goiffon, V.; Magnan, P.; Saint-Pe, O.; Bernard, F.; Rolland, G.

2009-01-01

Proton irradiation effects have been studied on CMOS image sensors manufactured in a 0.18μm technology dedicated to imaging. The ionizing dose and displacement damage effects were discriminated and localized thanks to 60 Co irradiations and large photodiode reverse current measurements. The only degradation observed was a photodiode dark current increase. It was found that ionizing dose effects dominate this rise by inducing generation centers at the interface between shallow trench isolations and depleted silicon regions. Displacement damages are is responsible for a large degradation of dark current non-uniformity. This work suggests that designing a photodiode tolerant to ionizing radiation can mitigate an important part of proton irradiation effects.

Current calibration, treatment, and treatment planning techniques among institutions participating in the Children's Oncology Group

International Nuclear Information System (INIS)

Urie, Marcia; FitzGerald, T.J.; Followill, David; Laurie, Fran; Marcus, Robert; Michalski, Jeff

2003-01-01

Purpose: To report current technology implementation, radiation therapy physics and treatment planning practices, and results of treatment planning exercises among 261 institutions belonging to the Children's Oncology Group (COG). Methods and Materials: The Radiation Therapy Committee of the newly formed COG mandated that each institution demonstrate basic physics and treatment planning abilities by satisfactorily completing a questionnaire and four treatment planning exercises designed by the Quality Assurance Review Center. The planning cases are (1) a maxillary sinus target volume (for two-dimensional planning), (2) a Hodgkin's disease mantle field (for irregular-field and off-axis dose calculations), (3) a central axis blocked case, and (4) a craniospinal irradiation case. The questionnaire and treatment plans were submitted (as of 1/30/02) by 243 institutions and completed satisfactorily by 233. Data from this questionnaire and analyses of the treatment plans with monitor unit calculations are presented. Results: Of the 243 clinics responding, 54% use multileaf collimators routinely, 94% use asymmetric jaws routinely, and 13% use dynamic wedges. Nearly all institutions calibrate their linear accelerators following American Association of Physicists in Medicine protocols, currently 16% with TG-51 and 81% with TG-21 protocol. Treatment planning systems are relied on very heavily for all calculations, including monitor units. Techniques and results of each of the treatment planning exercises are presented. Conclusions: Together, these data provide a unique compilation of current (2001) radiation therapy practices in institutions treating pediatric patients. Overall, the COG facilities have the equipment and the personnel to perform high-quality radiation therapy. With ongoing quality assurance review, radiation therapy compliance with COG protocols should be high

Gamma irradiation for sewage treatment at US army facilities

International Nuclear Information System (INIS)

Van den Berg, A.J.; Hollis, H.D.; Musselman, H.D.; Woodbridge, D.D.

1975-01-01

The US Army Corps of Engineers has been sponsoring research for many years on the use of gamma irradiation for disinfection and sterilization of sewage plant effluents. Initial research was directed to laboratory experiments using sterile solutions to determine the effects of gamma irradiation on E. coli, M-pyogenes and M-smegmatis organisms, and on the chemical constituents of sewage such as phenols, surfactants and pesticides. The results of the initial research warranted further study using municipal sewage secondary effluent as test samples. Current research is directed towards investigating the effects of radiation on the constituents of sewage sludge and on the cyst stage of the amoebic protozoa. Consideration has been given by the Corps to the management of waste-waters by disposal on land. Legal and medical reasons dictate that the plant effluents be sterilized before being used as fertilizers and soil conditioners. Gamma radiation from isotopic sources appears to be the best source of sterilizing energy for Army waste-water disposal. The Corps of Engineers is considering the construction of an experimental gamma irradiation pilot facility to validate laboratory experimental work and to establish design criteria for operating plants. The data obtained will provide a basis for performing detailed cost effectiveness studies on gamma irradiation as a method to treat secondary plant effluent. In addition, optimization work will be conducted to determine where in the sewage treatment cycle the use of gamma irradiation will produce the best results in meeting current and anticipated standards. (author)

Review of intense irradiation data and discussion on structural integrity

Energy Technology Data Exchange (ETDEWEB)

Suzuki, K.; Jitsukawa, S.; Okubo, N. [Japan Atomic Energy Agency, Tokai-mura, Naga-gun, Ibaraki-ken (Japan)

2007-07-01

Full text of publication follows: Mechanical property data on austenitic stainless steels and F82H have been reviewed to discuss for developing structural integrity methodologies of intensely irradiated components such as first walls. The following have been already clarified: (1) Fracture ductility is still high even though tensile rupture elongation is reduced remarkably. (2) Strain-hardening occurs in true stress-logarithmic strain (true strain) relationship. Work-softening behavior observed in nominal stress-nominal strain curves is simply resulted from a reduction of work hardening rate accompanied by the increase of flow stress level by irradiation. The review lead to an innovative design concept for application to intensely irradiated components. A special consideration is given to unique feature of bending moment in developing design methodology for preventing ductile fracture of intensely irradiated materials. Another discussion is also made on how to simulate mechanical behavior of intensely irradiated components, because mechanical testing of component-wise specimens after intense irradiation is inevitable for the development of design concepts, although irradiation on such a large scale specimen seems to be almost impossible with current irradiation facilities. (authors)

AGC-2 Specimen Post Irradiation Data Package Report

Energy Technology Data Exchange (ETDEWEB)

Windes, William Enoch [Idaho National Lab. (INL), Idaho Falls, ID (United States); Swank, W. David [Idaho National Lab. (INL), Idaho Falls, ID (United States); Rohrbaugh, David T. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Cottle, David L. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2015-08-01

This report documents results of the post-irradiation examination material property testing of the creep, control, and piggyback specimens from the irradiation creep capsule Advanced Graphite Creep (AGC)-2 are reported. This is the second of a series of six irradiation test trains planned as part of the AGC experiment to fully characterize the neutron irradiation effects and radiation creep behavior of current nuclear graphite grades. The AGC-2 capsule was irradiated in the Idaho National Laboratory Advanced Test Reactor at a nominal temperature of 600°C and to a peak dose of 5 dpa (displacements per atom). One-half of the creep specimens were subjected to mechanical stresses (an applied stress of either 13.8, 17.2, or 20.7 MPa) to induce irradiation creep. All post-irradiation testing and measurement results are reported with the exception of the irradiation mechanical strength testing, which is the last destructive testing stage of the irradiation testing program. Material property tests were conducted on specimens from 15 nuclear graphite grades using a similar loading configuration as the first AGC capsule (AGC-1) to provide easy comparison between the two capsules. However, AGC-2 contained an increased number of specimens (i.e., 487 total specimens irradiated) and replaced specimens of the minor grade 2020 with the newer grade 2114. The data reported include specimen dimensions for both stressed and unstressed specimens to establish the irradiation creep rates, mass and volume data necessary to derive density, elastic constants (Young’s modulus, shear modulus, and Poisson’s ratio) from ultrasonic time-of-flight velocity measurements, Young’s modulus from the fundamental frequency of vibration, electrical resistivity, and thermal diffusivity and thermal expansion data from 100–500°C. No data outliers were determined after all measurements were completed. A brief statistical analysis was performed on the irradiated data and a limited comparison between

Irradiation proctitis

International Nuclear Information System (INIS)

Minami, Akira

1977-01-01

Literatures on late rectal injuries are discussed, referring to two patients with uterine cervical cancer in whom irradiation proctitis occurred after telecobalt irradiation following uterine extirpation. To one patients, a total of 5000 rads was irradiated, dividing into 250 rads at one time, and after 3 months, irradiation with a total of 2000 rads, dividing into 200 rads at one time, was further given. In another one patient, two parallel opposing portal irradiation with a total of 6000 rads was given. About a year after the irradiation, rectal injuries and cystitis, accompanying with hemorrhage, were found in both of the patients. Rectal amputation and proctotoreusis were performed. Cystitis was treated by cystic irradiation in the urological department. Pathohistological studies of the rectal specimen revealed atrophic mucosa, and dilatation of the blood vessels and edema in the colonic submucosa. Incidence of this disease, term when the disease occurs, irradiation dose, type of the disease, treatment and prevention are described on the basis of the literatures. (Kanao, N.)

Irradiation proctitis

Energy Technology Data Exchange (ETDEWEB)

Minami, A [Osaka Kita Tsishin Hospital (Japan)

1977-06-01

Literatures on late rectal injuries are discussed, referring to two patients with uterine cervical cancer in whom irradiation proctitis occurred after telecobalt irradiation following uterine extirpation. To one patients, a total of 5000 rads was irradiated, dividing into 250 rads at one time, and after 3 months, irradiation with a total of 2000 rads, dividing into 200 rads at one time, was further given. In another one patient, two parallel opposing portal irradiation with a total of 6000 rads was given. About a year after the irradiation, rectal injuries and cystitis, accompanying with hemorrhage, were found in both of the patients. Rectal amputation and proctotoreusis were performed. Cystitis was treated by cystic irradiation in the urological department. Pathohistological studies of the rectal specimen revealed atrophic mucosa, and dilatation of the blood vessels and edema in the colonic submucosa. Incidence of this disease, term when the disease occurs, irradiation dose, type of the disease, treatment and prevention are described on the basis of the literatures.

Proton irradiation of CVD diamond detectors for high-luminosity experiments at the LHC

Energy Technology Data Exchange (ETDEWEB)

Meier, D. E-mail: dirk.meier@cern.ch.; Adam, W.; Bauer, C.; Berdermann, E.; Bergonzo, P.; Bogani, F.; Borchi, E.; Bruzzi, M.; Colledani, C.; Conway, J.; Dabrowski, W.; Delpierre, P.; Deneuville, A.; Dulinski, W.; Eijk, B. van; Fallou, A.; Foulon, F.; Friedl, M.; Jany, C.; Gan, K.K.; Gheeraert, E.; Grigoriev, E.; Hallewell, G.; Hall-Wilton, R.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kania, D.; Kaplon, J.; Kass, R.; Knoepfle, K.T.; Krammer, M.; Manfredi, P.F.; Marshall, R.D.; Mishina, M.; Le Normand, F.; Pan, L.S.; Palmieri, V.G.; Pernegger, H.; Pernicka, M.; Peitz, A.; Pirollo, S.; Pretzl, K.; Re, V.; Riester, J.L.; Roe, S.; Roff, D.; Rudge, A.; Schnetzer, S.; Sciortino, S.; Speziali, V.; Stelzer, H.; Stone, R.; Tapper, R.J.; Tesarek, R.; Thomson, G.B.; Trawick, M.; Trischuk, W.; Turchetta, R.; Walsh, A.M.; Wedenig, R.; Weilhammer, P.; Ziock, H.; Zoeller, M

1999-04-21

CVD diamond shows promising properties for use as a position-sensitive detector for experiments in the highest radiation areas at the Large Hadron Collider. In order to study the radiation hardness of diamond we exposed CVD diamond detector samples to 24 Gev/c and 500 Mev protons up to a fluence of 5x10{sup 15} p/cm{sup 2}. We measured the charge collection distance, the average distance electron-hole pairs move apart in an external electric field, and leakage currents before, during, and after irradiation. The charge collection distance remains unchanged up to 1x10{sup 15} p/cm{sup 2} and decreases by {approx}40% at 5x10{sup 15} p/cm{sup 2}. Leakage currents of diamond samples were below 1 pA before and after irradiation. The particle-induced currents during irradiation correlate well with the proton flux. In contrast to diamond, a silicon diode, which was irradiated for comparison, shows the known large increase in leakage current. We conclude that CVD diamond detectors are radiation hard to 24 GeV/c and 500 MeV protons up to at least 1x10{sup 15}p/cm{sup 2} without signal loss.

Preliminary Results From a Heavily Instrumented Engine Ice Crystal Icing Test in a Ground Based Altitude Test Facility

Science.gov (United States)

Flegel, Ashlie B.; Oliver, Michael J.

2016-01-01

Preliminary results from the heavily instrumented ALF502R-5 engine test conducted in the NASA Glenn Research Center Propulsion Systems Laboratory are discussed. The effects of ice crystal icing on a full scale engine is examined and documented. This same model engine, serial number LF01, was used during the inaugural icing test in the Propulsion Systems Laboratory facility. The uncommanded reduction of thrust (rollback) events experienced by this engine in flight were simulated in the facility. Limited instrumentation was used to detect icing on the LF01 engine. Metal temperatures on the exit guide vanes and outer shroud and the load measurement were the only indicators of ice formation. The current study features a similar engine, serial number LF11, which is instrumented to characterize the cloud entering the engine, detect/characterize ice accretion, and visualize the ice accretion in the region of interest. Data were acquired at key LF01 test points and additional points that explored: icing threshold regions, low altitude, high altitude, spinner heat effects, and the influence of varying the facility and engine parameters. For each condition of interest, data were obtained from some selected variations of ice particle median volumetric diameter, total water content, fan speed, and ambient temperature. For several cases the NASA in-house engine icing risk assessment code was used to find conditions that would lead to a rollback event. This study further helped NASA develop necessary icing diagnostic instrumentation, expand the capabilities of the Propulsion Systems Laboratory, and generate a dataset that will be used to develop and validate in-house icing prediction and risk mitigation computational tools. The ice accretion on the outer shroud region was acquired by internal video cameras. The heavily instrumented engine showed good repeatability of icing responses when compared to the key LF01 test points and during day-to-day operation. Other noticeable

High-dose irradiation: Wholesomeness of food irradiated with doses above 10 kGy. Report of a joint FAO/IAEA/WHO study group

International Nuclear Information System (INIS)

1999-01-01

This report presents the recommendations of an international group of experts convened by the World Health Organization, in association with the Food and Agriculture Organization of the United Nations and the International Atomic Energy Agency, to consider the implications of food irradiated to doses higher than those recommended in 1980 by the Joint Expert Committee on the Wholesomeness of Irradiated Food. Irradiation ensures the hygienic quality of food and extends shelf-life. The public perception of the safety of food irradiation has generally precluded its widespread use. However, current applications of food irradiation to doses over 10 kGy have been in the development of high-quality shelf-stable convenience foods for specific target groups such as immunosuppressed individuals and those under medical care, astronauts and outdoor enthusiasts. The Study Group reviewed data relating to the toxicological, nutritional, radiation chemical and physical aspects of food irradiated to doses above 10kGy from a wide range and number of studies carried out over the last forty years. This report presents a comprehensive summary, along with references, of the effectiveness and safety of the irradiation process. It concludes that foods treated with doses greater than 10kGy can be considered safe and nutritionally adequate when produced under established Good Manufacturing Practice

Toward superconducting critical current by design

OpenAIRE

Sadovskyy, I. A.; Jia, Y.; Leroux, M.; Kwon, J.; Hu, H.; Fang, L.; Chaparro, C.; Zhu, S.; Welp, U.; Zuo, J. -M.; Zhang, Y.; Nakasaki, R.; Selvamanickam, V.; Crabtree, G. W.; Koshelev, A. E.

2015-01-01

We present the new paradigm of critical current by design. Analogous to materials by design, it aims at predicting the optimal defect landscape in a superconductor for targeted applications by elucidating the vortex dynamics responsible for the bulk critical current. To highlight this approach, we demonstrate the synergistic combination of critical current measurements on commercial high-temperature superconductors containing self-assembled and irradiation tailored correlated defects by using...

Irradiation-accelerated corrosion of reactor core materials

International Nuclear Information System (INIS)

Bartels, David; Was, Gary; Jiao, Zhijie

2012-09-01

The combination of high temperature, chemically aggressive coolants, a high radiation flux and mechanical stress poses a major challenge for the life extension of current light water reactors, but also applies to most all other GenIV concepts. Of these four drivers, the combination of radiation and corrosion presents a unique and extremely challenging environment for materials, for which an understanding of the fundamental science is essentially absent. Irradiation can affect corrosion or oxidation in at least three different ways. Radiation interaction with water results in the decomposition of water into radicals and oxidizing species that will increase the electrochemical corrosion potential and lead to greater corrosion rates. Irradiation of the solid surface can produce excited states that can alter corrosion, such as in the case of photo-induced corrosion. Lastly, displacement damage in the solid will result in a high flux of defects to the solid-solution interface that can alter and perhaps, accelerate interface reactions. While there exists reasonable understanding of how corrosion is affected by irradiation of the aqueous environment, there is little understanding of how irradiation affects corrosion through its impact on the solid, whether metal or oxide. The reason is largely due to the difficulty of conducting experiments that can measure this effect separately. We have undertaken a project specifically to separate the several effects of irradiation on the mechanisms of corrosion. We seek to answer the question: How does radiation damage to the solution-oxide couple affect the oxidation process differently from radiation damage to either component alone? The approach taken in this work is to closely compare corrosion accelerated by (1) proton irradiation, (2) electron irradiation, and (3) chemical corrosion potential effects alone, under typical PWR operating conditions at 300 deg. C. Both 316 stainless steel and zirconium are to be studied. The proton

Ionic thermocurrent and optical-absorption measurements in KCl: Sr under reactor irradiation

International Nuclear Information System (INIS)

Sordi, G.M.; Watanabe, S.

1976-01-01

Radiation damage in KCl crystals doped with Sr ++ using thermionic-current techniques (ITC) and optical-absorption measurements is studied. Analysing the radiation damage due to three different gamma ray exposures, namely the gamma irradiation, creates F-type or V-type colour centres and destroys a fraction of impurity-vacancy dipoles. Fast neutron irradiation added to the gamma irradiation increases the efficiency of destruction of dipoles and also provoke the appearence of a second ITC peak at temperatures neat 123 0 K, which is unstable and disappears in a few days. On the other hand, thermal neutrons bombarding the samples together with fast neutrons and gamma-rays leave unchanged the impurity-vacancy dipole concentration obtained after the gamma plus fast neutron irradiation. With thermal neutrons there is a high background current, and the peak resolution is only possible when thermally and electrostatically polarizable electrical carriers have largely disappeared. For this reason it is impossible to compare the 123 0 K peak obtained with and without thermal neutrons

Studies on safety and efficiency of gamma-irradiated ginseng

International Nuclear Information System (INIS)

Kwon, Joong Ho; Cho, Han Ok; Byun, Myung Wo; Kim, Suc Won; Yang, Jae Seong; Yoo, Young Soo; Jin, Joon Ha; Park, Soon Chul

1991-09-01

Gamma irradiation was applied to the biological quality improvement and preservation of white ginseng which has problems in a hygienic quality and storage stability. The current phosphine treatment showed no influence on microorganisms contaminated even though it was very useful for disinfestation of the sample, while 5 kGy irradiation effectively controlled the biological quality of the stored sample, with minimal effects on the quality parameters of white ginseng. Thus, it is concluded that gamma irradiation at a range of 5 kGy can be an alternative method of chemical fumigants provided air-tight packaging excluding recontamination is used for the stored product. (Author)

Food irradiation

International Nuclear Information System (INIS)

Soothill, R.

1987-01-01

The issue of food irradiation has become important in Australia and overseas. This article discusses the results of the Australian Consumers' Association's (ACA) Inquiry into food irradiation, commissioned by the Federal Government. Issues discussed include: what is food irradiation; why irradiate food; how much food is consumer rights; and national regulations

Influence of Gamma Irradiation on Microbial Quality, Biological Properties and Some Chemical Compositions of Propolis and Bee Pollen In Egypt

International Nuclear Information System (INIS)

Eltablawy, S.Y.

2012-01-01

Propolis and bee pollen may be subjected to microbial contamination as a result of handling and storage, so, the current study was conducted to evaluate the microbial quality and quantity of Egyptian propolis and pollen and to study microbial contamination, antimicrobial activity, antioxidant activity and some chemical properties as amino acid composition and mineral content of irradiated and non-irradiated tested samples.The results showed that most samples were of unsatisfactory microbiological quality where the total bacterial and mold and yeast counts ranged between 6.6x10-6x10 6 CFU/g and 1.2 x 10 3 -3.7x10 3 CFU/g, respectively. Agar disk diffusion method was used for in vitro antimicrobial evaluation of propolis and pollen using water and 70% ethanolic extract against four gram positive, three gram negative bacteria and one yeast pathogens. The results exhibited that ethanolic extract has effective antibacterial activities than water extract. The free radical-scavenging activity of 70% ethanolic extract of the tested samples was determined using 1,1-diphenyl-2-picryl hydrazyl (DPPH). Pollen ethanolic extract showed higher antioxidant activity than propolis ethanolic extract. Amino acid profile of 70% ethanolic extract was determined. The results of the analysis showed the predominant amino acids in propolis and pollen were cystine and leucine, respectively. Mineral analysis of the tested samples was carried out by atomic absorption. The tested minerals were higher in pollen than in propolis except manganese and selenium. Propolis and pollen heavily bacterial and mold contaminated samples were subjected to increasing doses of gamma radiation (1-5 kGy). Exposure to 4 kGy was sufficient for microbial decontamination or reducing the count less than 10 CFU/g with no detectable effect on their antimicrobial activity. The same irradiation dose showed variable effects on amino acids and mineral content of the tested samples. Propolis and pollen have pharmacological

Thermo-stimulated current and dielectric loss in composite materials

International Nuclear Information System (INIS)

Nishijima, S.; Hagihara, T.; Okada, T.

1986-01-01

Thermo-stimulated current and dielectric loss measurements have been performed on five kinds of commercially available composite materials in order to study the electric properties of composite materials at low temperatures. Thermo-stimulated current measurements have been made on the composite materials in which the matrix quality was changed intentionally. The changes in the matrices were introduced by gamma irradiation or different curing conditions. Thermo-stimulated current and dielectric loss measurements revealed the number and the molecular weight of dipolar molecules. The different features of thermo-stimulated current and dielectric losses were determined for different composite materials. The gamma irradiation and the curing conditions especially affect the thermo-stimulated current features. The changes in macroscopic mechanical properties reflect those of thermo-stimulated current. It was found that the change in quality and/or degradation of the composite materials could be detected by means of thermo-stimulated current and/or dielectric loss measurements

Evaluation of irradiation hardening of proton irradiated stainless steels by nanoindentation

International Nuclear Information System (INIS)

Yabuuchi, Kiyohiro; Kuribayashi, Yutaka; Nogami, Shuhei; Kasada, Ryuta; Hasegawa, Akira

2014-01-01

Ion irradiation experiments are useful for investigating irradiation damage. However, estimating the irradiation hardening of ion-irradiated materials is challenging because of the shallow damage induced region. Therefore, the purpose of this study is to prove usefulness of nanoindentation technique for estimation of irradiation hardening for ion-irradiated materials. SUS316L austenitic stainless steel was used and it was irradiated by 1 MeV H + ions to a nominal displacement damage of 0.1, 0.3, 1, and 8 dpa at 573 K. The irradiation hardness of the irradiated specimens were measured and analyzed by Nix–Gao model. The indentation size effect was observed in both unirradiated and irradiated specimens. The hardness of the irradiated specimens changed significantly at certain indentation depths. The depth at which the hardness varied indicated that the region deformed by the indenter had reached the boundary between the irradiated and unirradiated regions. The hardness of the irradiated region was proportional to the inverse of the indentation depth in the Nix–Gao plot. The bulk hardness of the irradiated region, H 0 , estimated by the Nix–Gao plot and Vickers hardness were found to be related to each other, and the relationship could be described by the equation, HV = 0.76H 0 . Thus, the nanoindentation technique demonstrated in this study is valuable for measuring irradiation hardening in ion-irradiated materials

Measurement of surface recombination velocity on heavily doped indium phosphide

International Nuclear Information System (INIS)

Jenkins, P.; Ghalla-Goradia, M.; Faur, M.; Bailey, S.

1990-01-01

The controversy surrounding the published low values of surface recombination velocity (SRV) in n-InP, solidified in recent years when modeling of existing n/p InP solar cells revealed that the front surface SRV had to be higher than 1 x 10 6 cm/sec in order to justify the poor blue response that is characteristic of all n/p InP solar cells. In this paper, SRV on heavily doped (>10 18 cm -3 )n-type and p-type InP is measured as a function of surface treatment. For the limited range of substrates and surface treatments studied, SRV and surface stability depend strongly on the surface treatment. SRVs of ∼10 5 cm/sec in both p-type and n-type InP are obtainable, but in n-type the low SRV surfaces were unstable, and the only stable surfaces on n-type had SRVs of >10 6 cm/sec

Heavily-doped 2D-quantized structures and the Einstein relation

CERN Document Server

Ghatak, Kamakhya P

2015-01-01

This book presents the Einstein Relation(ER) in two-dimensional (2-D) Heavily Doped(HD) Quantized Structures. The materials considered are quantized structures of HD non-linear optical, III-V, II-VI, Ge, Te, Platinum Antimonide, stressed materials, GaP, Gallium Antimonide, II-V, Bismuth Telluride together with various types of HD superlattices and their Quantized counterparts respectively. The ER in HD opto-electronic materials and their nanostructures is studied in the presence of strong light waves and intense electric fields on the basis of newly formulated electron dispersion laws that control the studies of such quantum effect devices. The suggestion for the experimental determination of HD 2D and 3D ERs and the importance of measurement of band gap in HD optoelectronic materials under intense built-in electric field in nanodevices and strong external photo excitation (for measuring photon induced physical properties) are also discussed in this context. The influence of crossed electric and quantizing ma...

Space-charge dynamics of polymethylmethacrylate under electron beam irradiation

CERN Document Server

Gong, H; Ong, C K

1997-01-01

Space-charge dynamics of polymethylmethacrylate (PMMA) under electron beam irradiation has been investigated employing a scanning electron microscope. Assuming a Gaussian space-charge distribution, the distribution range (sigma) has been determined using a time-resolved current method in conjunction with a mirror image method. sigma is found to increase with irradiation time and eventually attain a stationary value. These observations have been discussed by taking into account radiation-induced conductivity and charge mobility. (author)

Post irradiation test report of irradiated DUPIC simulated fuel

International Nuclear Information System (INIS)

Yang, Myung Seung; Jung, I. H.; Moon, J. S. and others

2001-12-01

The post-irradiation examination of irradiated DUPIC (Direct Use of Spent PWR Fuel in CANDU Reactors) simulated fuel in HANARO was performed at IMEF (Irradiated Material Examination Facility) in KAERI during 6 months from October 1999 to March 2000. The objectives of this post-irradiation test are i) the integrity of the capsule to be used for DUPIC fuel, ii) ensuring the irradiation requirements of DUPIC fuel at HANARO, iii) performance verification in-core behavior at HANARO of DUPIC simulated fuel, iv) establishing and improvement the data base for DUPIC fuel performance verification codes, and v) establishing the irradiation procedure in HANARO for DUPIC fuel. The post-irradiation examination performed are γ-scanning, profilometry, density, hardness, observation the microstructure and fission product distribution by optical microscope and electron probe microanalyser (EPMA)

Facts about food irradiation: Irradiated foods and the consumer

International Nuclear Information System (INIS)

1991-01-01

This fact sheet discusses market testing of irradiate food, consumer response to irradiated products has always been positive, and in some countries commercial quantities of some irradiated food items have been sold on a regular basis. Consumers have shown no reluctance to buy irradiated food products. 4 refs

Gamma Irradiation does not Cause Carcinogenesis of Irradiated Herbs

International Nuclear Information System (INIS)

Thongphasuk, Jarunee; Thongphasuk, Piyanuch; Eamsiri, Jarurut; Pongpat, Suchada

2009-07-01

Full text: Microbial contamination of medicinal herbs can be effectively reduced by gamma irradiation. Since irradiation may cause carcinogenicity of the irradiated herbs, the objective of this research is to study the effect of gamma irradiation (10 and 25 kGy) from cobalt-60 on carcinogenicity. The herbs studied were Pueraria candollei Grah., Curcuma longa Linn. Zingiber montanum, Senna alexandrina P. Miller, Eurycoma Longifolia Jack, Gymnostema pentaphylum Makino, Ginkgo biloba, Houttuynia cordata T., Andrographis paniculata, Thunbergia laurifolia L., Garcinia atroviridis G., and Cinnamomum verum J.S.Presl. The results showed that gamma irradiation at the dose of 10 and 25 kGy did not cause carcinogenicity of the irradiated herbs

Testbeam and laboratory test results of irradiated 3D CMS pixel detectors

Energy Technology Data Exchange (ETDEWEB)

Bubna, Mayur [Purdue University, Department of Physics, West Lafayette, IN 47907-1396 (United States); Purdue University, School of Electrical and Computer Engineering, West Lafayette, IN 47907-1396 (United States); Alagoz, Enver, E-mail: enver.alagoz@cern.ch [Purdue University, Department of Physics, West Lafayette, IN 47907-1396 (United States); Cervantes, Mayra; Krzywda, Alex; Arndt, Kirk [Purdue University, Department of Physics, West Lafayette, IN 47907-1396 (United States); Obertino, Margherita; Solano, Ada [Istituto Nazionale di Fisica Nucleare, Sezione di Torino, 10125 Torino (Italy); Dalla Betta, Gian-Franco [INFN Padova (Gruppo Collegato di Trento) (Italy); Dipartimento di Ingegneria e Scienzadella Informazione, Universitá di Trento, I-38123 Povo di Trento (Italy); Menace, Dario; Moroni, Luigi [Istituto Nazionale di Fisica Nucleare, Sezione di Milano Bicocca (Italy); Universitá degli Studi di Milano Bicocca, 20126 Milano (Italy); Uplegger, Lorenzo; Rivera, Ryan [Fermi National Accelerator Laboratory, Batavia, IL 60510-0500 (United States); Osipenkov, Ilya [Texas A and M University, Department of Physics, College Station, TX 77843-4242 (United States); Andresen, Jeff [Fermi National Accelerator Laboratory, Batavia, IL 60510-0500 (United States); Bolla, Gino; Bortoletto, Daniela [Purdue University, Department of Physics, West Lafayette, IN 47907-1396 (United States); Boscardin, Maurizio [Centro per i Materiali e i Microsistemi Fondazione Bruno Kessler (FBK), Trento, I-38123 Povo di Trento (Italy); Marie Brom, Jean [Strasbourg IPHC, Institut Pluriedisciplinaire Hubert Curien, F-67037 Strasbourg Cedex (France); Brosius, Richard [State University of New York at Buffalo (SUNY), Department of Physics, Buffalo, NY 14260-1500 (United States); Chramowicz, John [Fermi National Accelerator Laboratory, Batavia, IL 60510-0500 (United States); and others

2013-12-21

The CMS silicon pixel detector is the tracking device closest to the LHC p–p collisions, which precisely reconstructs the charged particle trajectories. The planar technology used in the current innermost layer of the pixel detector will reach the design limit for radiation hardness at the end of Phase I upgrade and will need to be replaced before the Phase II upgrade in 2020. Due to its unprecedented performance in harsh radiation environments, 3D silicon technology is under consideration as a possible replacement of planar technology for the High Luminosity-LHC or HL-LHC. 3D silicon detectors are fabricated by the Deep Reactive-Ion-Etching (DRIE) technique which allows p- and n-type electrodes to be processed through the silicon substrate as opposed to being implanted through the silicon surface. The 3D CMS pixel devices presented in this paper were processed at FBK. They were bump bonded to the current CMS pixel readout chip, tested in the laboratory, and testbeams carried out at FNAL with the proton beam of 120 GeV/c. In this paper we present the laboratory and beam test results for the irradiated 3D CMS pixel devices. -- Highlights: •Pre-irradiation and post-irradiation electrical properties of 3D sensors and 3D diodes from various FBK production batches were measured and analyzed. •I–T measurements of gamma irradiated diodes were analyzed to understand leakage current generation mechanism in 3D diodes. •Laboratory measurements: signal to noise ratio and charge collection efficiency of 3D sensors before and after irradiation. •Testbeam measurements: pre- and post-irradiation pixel cell efficiency and position resolution of 3D sensors.

Food irradiation

International Nuclear Information System (INIS)

Duchacek, V.

1989-01-01

The ranges of doses used for food irradiation and their effect on the processed foods are outlined. The wholesomeness of irradiated foods is discussed. The present food irradiation technology development in the world is described. A review of the irradiated foods permitted for public consumption, the purposes of food irradiaton, the doses used and a review of the commercial-scale food irradiators are tabulated. The history and the present state of food processing in Czechoslovakia are described. (author). 1 fig., 3 tabs., 13 refs

Terminal load response law of coaxial cable to continuous wave electromagnetic irradiation

International Nuclear Information System (INIS)

Pan Xiaodong; Wei Guanghui; Li Xinfeng; Lu Xinfu

2012-01-01

In order to study the coupling response law of continuous wave electromagnetic irradiation to coaxial cable, the typical RF coaxial cable is selected as the object under test. The equipment or subsystem connected by coaxial cable is equivalent to a lumped load. Continuous wave irradiation effect experiments under different conditions are carried out to analyze the terminal load response law of coaxial cable. The results indicate that the coaxial cable has a frequency selecting characteristic under electromagnetic irradiation, and the terminal load response voltage peak appears at a series of discrete frequency points where the test cable's relative lengths equal to semi-integers. When the coaxial cable is irradiated by continuous wave, the induced sheath current converts to the differential-mode induced voltage between inner conductor and shielding layer through transfer impedance, and the internal resistance of induced voltage source is the characteristic impedance of the coaxial cable. The change in terminal load value has no influence on the response curve. The voltages on the terminal load and the internal resistance of equivalent induced voltage source obey the principle of voltage division. Moreover, when the sheath current on the coaxial cable is in resonance, the distributed induced voltage between adjacent current nodes is in the same polarity, which can be equivalent to a single induced voltage source. The induced voltage source which is adjacent to the terminal load plays the leading role in the irradiation response process. (authors)

Development of integrated waste management options for irradiated graphite

Energy Technology Data Exchange (ETDEWEB)

Wareing, Alan; Abrahamsen-Mills, Liam; Fowler, Linda; Jarvis, Richard; Banford, Anthony William [National Nuclear Laboratory, Warrington (United Kingdom); Grave, Michael [Doosan Babcock, Gateshead (United Kingdom); Metcalfe, Martin [National Nuclear Laboratory, Gloucestershire (United Kingdom); Norris, Simon [Radioactive Waste Management Limited, Oxon (United Kingdom)

2017-08-15

The European Treatment and Disposal of Irradiated Graphite and other Carbonaceous Waste project sought to develop best practices in the retrieval, treatment, and disposal of irradiated graphite including other irradiated carbonaceous waste such as structural material made of graphite, nongraphitized carbon bricks, and fuel coatings. Emphasis was given on legacy irradiated graphite, as this represents a significant inventory in respective national waste management programs. This paper provides an overview of the characteristics of graphite irradiated during its use, primarily as a moderator material, within nuclear reactors. It describes the potential techniques applicable to the retrieval, treatment, recycling/reuse, and disposal of these graphite wastes. Considering the lifecycle of nuclear graphite, from manufacture to final disposal, a number of waste management options have been developed. These options consider the techniques and technologies required to address each stage of the lifecycle, such as segregation, treatment, recycle, and ultimate disposal in a radioactive waste repository, providing a toolbox to aid operators and regulators to determine the most appropriate management strategy. It is noted that national waste management programs currently have, or are in the process of developing, respective approaches to irradiated graphite management. The output of the Treatment and Disposal of Irradiated Graphite and other Carbonaceous Waste project is intended to aid these considerations, rather than dictate them.

Irradiation effects in low T$_{c}$ superconductors

CERN Document Server

Flükiger, René

2009-01-01

The effects of neutron irradiation on the superconducting parameters Tc, Bc2 and Jc of Nb3Sn are reviewed in view of the determination of the radiation limit in the LHC upgrade magnets. The variation of Jc in binary as well as in Ti and Ta alloyed Nb3Sn wires is presented. The coexisting defect mechanisms in irradiated Nb3Sn type compounds are briefly presented and a model is discussed explaining the site exchange mechanism which leads to a decrease of atomic ordering after irradiation. Based on calculations of F. Cerutti and coworkers (CERN), the neutron fluence at the inner winding of the quadrupole Q2a is estimated to values below 1018 neutrons /cm2 for a life time of 10 years, which is within the safety margin with respect to the critical current density and Bc2.

In-service irradiated and aged material evaluations

International Nuclear Information System (INIS)

Haggag, F.M.; Nanstad, R.K.; Alexander, D.J.

1995-01-01

The objective of this task is to provide a direct assessment of actual material properties in irradiated components of nuclear reactors, including the effects of irradiation and aging. Four activities are currently in progress: (1) establishing a machining capability for contaminated or activated materials by completing procurement and installation of a computer-based milling machine in a hot cell; (2) machining and testing specimens from cladding materials removed from the Gundremmingen reactor to establish their fracture properties; (3) preparing an interpretive report on the effects of neutron irradiation on cladding; and (4) continuing the evaluation of long-term aging of austenitic structural stainless steel weld metal by metallurgically examining and testing specimens aged at 288 and 343 degrees C and reporting the results, as well as by continuing the aging of the stainless steel cladding toward a total time of 50,000 h

Global trends of acceptance and trade in irradiated foods

Energy Technology Data Exchange (ETDEWEB)

Matin, M A [Food and Environmental Protection Section, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, International Atomic Energy Agency, Vienna (Austria)

2001-05-01

Issues as relevant to wide scale application of food irradiation are presented in this paper to provide current status of the technology. Global development on key issues such as public acceptance, public health improvement, safety and wholesomeness, regulatory aspects, potential application of the technology to ease quarantine problems in the trade of food and agricultural commodities as a viable alternative to fumigation with methyl bromide have been presented. Irradiation ensures the hygienic quality of food and extends shelf-life. Many international organizations and respected regional/national bodies agree on the merits of the technique and valuable contribution that the process can offer to safeguard the food supply worldwide. Codex General Standard for irradiated food and the associated Code of Practice for operation of the irradiation facilities used for the treatment of foods adopted in 1983 forms the regulatory basis for commercial utilization of the processing technology. More than 40 countries of the world have Standards/Regulations to process one or more food products by the irradiation process. Efforts are underway to harmonise national regulations on food irradiation to remove obstacles for international trade of irradiated products. There is a rapid development on commercial application of food irradiation in the USA and elsewhere in the past few months. There are already several existing commercial irradiators available for treating food in the USA and many more are planned to be built. Such commercial food irradiation facilities are also in different stage of development in Brazil, India, Mexico, Thailand, People's Republic of China, Republic of Korea. Roles of irradiation ensuring food safety, contributing food security and facilitating trade are more and more recognized in developed and developing countries alike. (author)

Global trends of acceptance and trade in irradiated foods

International Nuclear Information System (INIS)

Matin, M.A.

2001-01-01

Issues as relevant to wide scale application of food irradiation are presented in this paper to provide current status of the technology. Global development on key issues such as public acceptance, public health improvement, safety and wholesomeness, regulatory aspects, potential application of the technology to ease quarantine problems in the trade of food and agricultural commodities as a viable alternative to fumigation with methyl bromide have been presented. Irradiation ensures the hygienic quality of food and extends shelf-life. Many international organizations and respected regional/national bodies agree on the merits of the technique and valuable contribution that the process can offer to safeguard the food supply worldwide. Codex General Standard for irradiated food and the associated Code of Practice for operation of the irradiation facilities used for the treatment of foods adopted in 1983 forms the regulatory basis for commercial utilization of the processing technology. More than 40 countries of the world have Standards/Regulations to process one or more food products by the irradiation process. Efforts are underway to harmonise national regulations on food irradiation to remove obstacles for international trade of irradiated products. There is a rapid development on commercial application of food irradiation in the USA and elsewhere in the past few months. There are already several existing commercial irradiators available for treating food in the USA and many more are planned to be built. Such commercial food irradiation facilities are also in different stage of development in Brazil, India, Mexico, Thailand, People's Republic of China, Republic of Korea. Roles of irradiation ensuring food safety, contributing food security and facilitating trade are more and more recognized in developed and developing countries alike. (author)

Marine reserves and reproductive biomass: a case study of a heavily targeted reef fish.

Directory of Open Access Journals (Sweden)

Brett M Taylor

Full Text Available Recruitment overfishing (the reduction of a spawning stock past a point at which the stock can no longer replenish itself is a common problem which can lead to a rapid and irreversible fishery collapse. Averting this disaster requires maintaining a sufficient spawning population to buffer stochastic fluctuations in recruitment of heavily harvested stocks. Optimal strategies for managing spawner biomass are well developed for temperate systems, yet remain uncertain for tropical fisheries, where the danger of collapse from recruitment overfishing looms largest. In this study, we explored empirically and through modeling, the role of marine reserves in maximizing spawner biomass of a heavily exploited reef fish, Lethrinus harak around Guam, Micronesia. On average, spawner biomass was 16 times higher inside the reserves compared with adjacent fished sites. Adult density and habitat-specific mean fish size were also significantly greater. We used these data in an age-structured population model to explore the effect of several management scenarios on L. harak demography. Under minimum-size limits, unlimited extraction and all rotational-closure scenarios, the model predicts that preferential mortality of larger and older fish prompt dramatic declines in spawner biomass and the proportion of male fish, as well as considerable declines in total abundance. For rotational closures this occurred because of the mismatch between the scales of recovery and extraction. Our results highlight how alternative management scenarios fall short in comparison to marine reserves in preserving reproductively viable fish populations on coral reefs.

Electrical conductivity tensor of an irradiated metal

International Nuclear Information System (INIS)

Corciovei, A.; Dumitru, R.D.

1979-01-01

A method to calculate the electrical conductivity tensor of an irradiated metal is presented. The proposed method relies on the use of the Kubo formula, evaluated by a perturbation method. The one electron Hamiltonian is written as a sum of two terms: the Hamiltonian of the conduction electrons moving in a periodic lattice and the perturbation, namely, the scattering potential due to the irradiation defects of the ideal crystal. Then, the lowest order of the conductivity is determined by the lowest order of the Laplace transform of the current. An integral equation is written for this last quantity. (author)

Multipulse nanosecond laser irradiation of silicon for the investigation of surface morphology and photoelectric properties

Science.gov (United States)

Sardar, Maryam; Chen, Jun; Ullah, Zaka; Jelani, Mohsan; Tabassum, Aasma; Cheng, Ju; Sun, Yuxiang; Lu, Jian

2017-12-01

We irradiate the single crystal boron-doped silicon (Si) with different number of laser pulses at constant fluence (7.5 J cm-2) in ambient air using Nd:YAG laser and examine its surface morphology and photoelectric properties in details. The results obtained from optical micrographs reveal the increase in heat affected zone (HAZ) and melted area of laser irradiated Si with increasing number of laser pulses. The SEM micrographs evidence the formation of various surface morphologies like laser induced periodic surface structures, crater, microcracks, clusters, cavities, pores, trapped bubbles, nucleation sites, micro-bumps, redeposited material and micro- and nano-particles on the surface of irradiated Si. The surface profilometry analysis informs that the depth of crater is increased with increase in number of incident laser pulses. The spectroscopic ellipsometry reveals that the multipulse irradiation of Si changes its optical properties (refractive index and extinction coefficient). The current-voltage (I-V) characteristic curves of laser irradiated Si show that although the multipulse laser irradiation produces considerable number of surface defects and damages, the electrical properties of Si are well sustained after the multipulse irradiation. The current findings suggest that the multipulse irradiation can be an effective way to tune the optical properties of Si for the fabrication of wide range of optoelectronic devices.

Transportation of irradiated fuel elements

International Nuclear Information System (INIS)

1980-01-01

A critique is presented of current methods of transporting spent nuclear fuel and the inadequacies of the associated contingency plans, with particular reference to the transportation of irradiated fuel through London. Anti-nuclear and pro-nuclear arguments are presented on a number of factors, including tests on flasks, levels of radiation exposure, routine transport arrangements and contingency arrangements. (U.K.)

IFMIF [International Fusion Materials Irradiation Facility], an accelerator-based neutron source for fusion components irradiation testing: Materials testing capabilities

International Nuclear Information System (INIS)

Mann, F.M.

1988-08-01

The International Fusion Materials Irradiation Facility (IFMIF) is proposed as an advanced accelerator-based neutron source for high-flux irradiation testing of large-sized fusion reactor components. The facility would require only small extensions to existing accelerator and target technology originally developed for the Fusion Materials Irradiation Test (FMIT) facility. At the extended facility, neutrons would be produced by a 0.1-A beam of 35-MeV deuterons incident upon a liquid lithium target. The volume available for high-flux (>10/sup 15/ n/cm/sup 2/-s) testing in IFMITF would be over a liter, a factor of about three larger than in the FMIT facility. This is because the effective beam current of 35-MeV deuterons on target can be increased by a factor of ten to 1A or more. Such an increase can be accomplished by funneling beams of deuterium ions from the radio-frequency quadruple into a linear accelerator and by taking advantage of recent developments in accelerator technology. Multiple beams and large total current allow great variety in available testing. For example, multiple simultaneous experiments, and great flexibility in tailoring spatial distributions of flux and spectra can be achieved. 5 refs., 2 figs., 1 tab

Quarantine treatment of agricultural products for export and import by gamma irradiation

Energy Technology Data Exchange (ETDEWEB)

Kwon, Joong Ho; Roh, M.J.; Chung, H.W.; Lee, J.E.; Park, N.Y.; Kwon, Y.J.; Seo, S.J. [Kyungbuk National University, Taegu (Korea)

1999-04-01

To pre-establish an alternative technique to the toxic fumigant, methyl bromide which is the current quarantine measure of agricultural products for export and import, some selected agricultural products, such as chestnut, acorn, red bean and mung bean, were subjected to a preliminary study to confirm the comparative effects of gamma irradiation and MBr fumigant on their disinfestation and quality, thereby preparing the basic data for the practical approach. Current quarantine activities were examined and the related limitations were investigated. Quarantine-related pests were investigated on their radiosensitivity and disinfestation effects by both treatments. The pests in chestnut and acorn, Curculio skkimensis Heller, Curculio dentipes Roelofs, and Dichocrocis punctiferalis Guenee showed an increased mortality when exposed to above 0.5 kGy irradiation, resulting in 100% of mortality three weeks later. Callosobruchus chinensis Linne from both red and mung beans revealed a apparent mortality at around 10 days after irradiation of 1 to 3 kGy. Current fumigation was perfect in its disinfesting capability, but it caused the detrimental effects on physical quality of agricultural produce. Whereas, irradiation doses suitable for controlling the pests did not induce any significant changes in the quality of the samples. (author). 53 refs., 74 figs., 138 tabs.

Charge collection in Si detectors irradiated in situ at superfluid helium temperature

Energy Technology Data Exchange (ETDEWEB)

Verbitskaya, Elena, E-mail: elena.verbitskaya@cern.ch [Ioffe Institute, 26 Politekhnicheskaya str., St. Petersburg 194021 (Russian Federation); Eremin, Vladimir; Zabrodskii, Andrei [Ioffe Institute, 26 Politekhnicheskaya str., St. Petersburg 194021 (Russian Federation); Dehning, Bernd; Kurfürst, Christoph; Sapinski, Mariusz; Bartosik, Marcin R. [CERN, CH-1211, Geneva 23 (Switzerland); Egorov, Nicolai [Research Institute of Material Science and Technology, 4 Passage 4806, Moscow, Zelenograd 124460 (Russian Federation); Härkönen, Jaakko [Helsinki Institute of Physics, P.O.Box 64 (Gustaf Hallströmin katu 2) FI-00014 University of Helsinki (Finland)

2015-10-01

Silicon and diamond detectors operated in a superfluid helium bath are currently being considered for the upgrade of the LHC beam loss monitoring system. The detectors would be installed in immediate proximity of the superconducting coils of the triplet magnets. We present here the results of the in situ irradiation test for silicon detectors using 23 GeV protons while keeping the detectors at a temperature of 1.9 K. Red laser (630 nm) Transient Current Technique and DC current measurements were used to study the pulse response and collected charge for silicon detectors irradiated to a maximum radiation fluence of 1×10{sup 16} p/cm{sup 2}. The dependence between collected charge and irradiation fluence was parameterized using the Hecht equation and assumption of a uniform electric field distribution. The collected charge was found to degrade with particle fluence for both bias polarities. We observed that the main factor responsible for this degradation was related to trapping of holes on the donor-type radiation-induced defects. In contrast to expectations, along with formation of donors, acceptor-type defects (electron traps) are introduced into the silicon bulk. This suggests that the current models describing charge collection in irradiated silicon detectors require an extension for taking into account trapping at low temperatures with a contribution of shallow levels. New in situ irradiation tests are needed and planned now to extend statistics of the results and gain a deeper insight into the physics of low temperature detector operation in harsh radiation environment. - Highlights: • Si detectors irradiated in situ at 1.9 K by 23 GeV protons are further studied. • Trapping parameters are derived from the fits of collected charge vs. fluence data. • Acceptor-type defects are likely to be induced along with donor-type ones. • Trapping of holes has a dominating effect on the collected charge degradation. • New tests are planned to gain deeper insight

Knowledge and views of professors of nutrition about food irradiation

International Nuclear Information System (INIS)

Silva, Kelly Daiane; Braga, Vilma de Oliveira; Quintaes, Kesia Diego

2010-01-01

Food irradiation is an efficient technology that can be used in the conservation of foods. However, consumers' knowledge about irradiated foods has proved insufficient resulting in low acceptance of such foods. Considering that dietitians and nutritionists are the qualified health professionals to guide patients and consumers towards the ingestion and selection of foods, this study aims to evaluate the knowledge and views about radiated foods of professors of nutrition working in higher education institutions in the city of Belo Horizonte - MG, Brazil. A total of 86.4% out of the 66 participants had general knowledge about irradiated foods. However, 71.2% were not familiar with the process, 75.8% were totally unaware of the specific legislation, 21.2% were not sure of the purposes of irradiation, 12.1% considered irradiated foods radioactive, and 31.8% believed that food irradiation results in the reduction of the nutritional value of foods. Irradiated foods would not be rejected by professionals with Ph.D. degree, but they would be rejected by five masters and six experts questioned. The study concluded that the current higher education of future dietitians and nutritionists has been provided without the minimum necessary knowledge regarding irradiated foods corroborating the negative view of consumers about this kind of food. (author)

Ag Transport Through Non-Irradiated and Irradiated SiC

Energy Technology Data Exchange (ETDEWEB)

Szlufarska, Izabela [Univ. of Wisconsin, Madison, WI (United States); Morgan, Dane [Univ. of Wisconsin, Madison, WI (United States); Blanchard, James [Univ. of Wisconsin, Madison, WI (United States)

2016-01-11

Silicon carbide is the main barrier to diffusion of fission products in the current design of TRistuctural ISOtropic (TRISO) coated fuel particles, and Ag is one of the few fission products that have been shown to escape through this barrier. Because the SiC coating in TRISO is exposed to radiation throughout the lifetime of the fuel, understanding of how radiation changes the transport of the fission products is essential for the safety of the reactor. The goals of this project are: (i) to determine whether observed variation in integral release measurements of Ag through SiC can be explained by differences in grain size and grain boundary (GB) types among the samples; (2) to identify the effects of irradiation on diffusion of Ag through SiC; (3) to discover phenomena responsible for significant solubility of Ag in polycrystalline SiC. To address these goals, we combined experimental analysis of SiC diffusion couples with modeling studies of diffusion mechanisms through bulk and GBs of this material. Comparison between results obtained for pristine and irradiated samples brings in insights into the effects of radiation on Ag transport.

Ag Transport Through Non-Irradiated and Irradiated SiC

International Nuclear Information System (INIS)

Szlufarska, Izabela; Morgan, Dane; Blanchard, James

2016-01-01

Silicon carbide is the main barrier to diffusion of fission products in the current design of TRistuctural ISOtropic (TRISO) coated fuel particles, and Ag is one of the few fission products that have been shown to escape through this barrier. Because the SiC coating in TRISO is exposed to radiation throughout the lifetime of the fuel, understanding of how radiation changes the transport of the fission products is essential for the safety of the reactor. The goals of this project are: (i) to determine whether observed variation in integral release measurements of Ag through SiC can be explained by differences in grain size and grain boundary (GB) types among the samples; (2) to identify the effects of irradiation on diffusion of Ag through SiC; (3) to discover phenomena responsible for significant solubility of Ag in polycrystalline SiC. To address these goals, we combined experimental analysis of SiC diffusion couples with modeling studies of diffusion mechanisms through bulk and GBs of this material. Comparison between results obtained for pristine and irradiated samples brings in insights into the effects of radiation on Ag transport.

An introduction to the irradiation processing of foods

International Nuclear Information System (INIS)

Hackwood, S.

1991-01-01

The food industry has used a variety of methods over the years to preserve or extend the shelf life of food. These have included cooking, packaging, smoking, chilling, freezing, dehydrating and using chemical additives. More recently, ionising radiation has been used to extend the storage life of foods. More research has been focussed on the effects of irradiation on foods than has been directed at any other form of food processing. This research has spanned 40 years and has been carried out in many countries. Food irradiation can be used to: (a) inhibit the sprouting of vegetables; (b) delay the ripening of fruits; (c) kill insect pests in fruit, grains or spices; (d) reduce or eliminate food spoilage organisms; (e) reduce food poisoning bacteria on some meats and sea food products. This chapter includes sections on the historical background; general aspects of radiation; scientific, technological, microbiological and toxicological aspects of food irradiation; nutritional aspects of food irradiation; consumer attitudes; current status and legislation; labelling. It concludes that the relatively new process of preserving food by irradiation compliments rather than competes with the presently available traditional methods. (author)

Low frequency alternating current conduction and dielectric relaxation in polypyrrole irradiated with 100 MeV swift heavy ions of silver (Ag{sup 8+})

Energy Technology Data Exchange (ETDEWEB)

Kaur, Amarjeet, E-mail: amarkaur@physics.du.ac.in [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India); Dhillon, Anju [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India); Avasthi, D.K. [Inter University Accelerator Center (IUAC), Aruna Asaf Ali Road, New Delhi 110067 (India)

2013-07-15

Polypyrrole (PPY) films were prepared by electrochemical polymerization technique. The fully undoped samples were irradiated with different radiation fluences ranging from 10{sup 10} to 10{sup 12} ions cm{sup −2} of 100 MeV silver (Ag{sup 8+}) ions. The temperature dependence of ac conductivity [σ{sub m}(ω)], dielectric constant (ε′) and dielectric loss (ε′′) of both irradiated as well as unirradiated samples have been investigated in 77–300 K. There exists typical Debye type dispersion. Giant increase in dielectric constant has been observed for irradiated samples which is attributed to polaronic defects produced during irradiation. - Graphical abstract: Display Omitted - Highlights: • Polypyrrole samples were prepared by electrochemical technique. • The fully undoped samples were irradiated with 100 MeV silver (Ag{sup 8+}) ions. • Giant increase in dielectric constant in irradiated samples is observed. • Dielectric behaviour is attributed to polaronic defects produced during irradiation.

Termite feeding preference to four wood species after gamma irradiation

International Nuclear Information System (INIS)

Katsumata, N.; Yoshimura, T.; Tsunoda, K.; Imamura, Y.

2007-01-01

The effect of gamma irradiation at 100 kGy and at lower levels on termite resistance was examined in the laboratory by no-choice and choice feeding termite tests (Coptotermes formosanus Shiraki) using four wood species: sapwood of Cryptomeria japonica D. Don, and heartwoods of Pseudotsuga menziesii (Mirbel) Franco, Larix kaempferi (Lambert) Carriere, and Chamaecyparis obtusa Endl. The wood consumption rates in C. japonica and P. menziesii specimens were likely to increase with increases in gamma-irradiation levels, whereas little effect of gamma irradiation was seen in L. kaempferi and C. obtusa. Similar results were obtained in the two-choice test. The current results indicated that in the two-choice test with C. formosanus, 100-kGy-irradiated C. japonica and P. menziesii, which are not rich in antitermite substances, were eaten more than other wood samples with or without gamma irradiation. However, only C. japonica showed significant difference in termite feeding activity. The mass loss in 100-kGy-irradiated C. japonica was significantly higher in the multichoice test

MYRRHA, A Flexible Fast Spectrum Irradiation Facility. Current Status of Design

International Nuclear Information System (INIS)

Baeten, Peter; Fernandez, Rafaël; De Bruyn, Didier; Van den Eynde, Gert; Leysen, Paul; Aït Abderrahim, Hamid; Castelliti, Diego

2011-01-01

R and D program in support of MYRRHA: • Several R&D required for MYRRHA components: - LBE corrosion; - O 2 control in LBE; - Irradiated material properties. • Experimental facilities foreseen in the near future in support of MYRRHA at SCK•CEN premacies: - E-SCAPE: Thermal-hydraulic pool facility with 1:6 scale ratio with MYRRHA; - Liliputter: Pump test loop; - COMPLOT: Isothermal hydraulic loop representing one fuel channel/IPS at full high; - PHX mock-up testing concept, fouling, flow-induced vibrations, (SGTR)…; • Experimental facilities foreseen in the near future in support of MYRRHA at SCK•CEN premacies (continued): - Safety/control rod; - Fuel bundle; - Target window; - Component test pool; - Fuel loader; - Robotic arm; • All experiments planned to be finished before 2016

Irradiation devices at the upgraded research reactor BER II

International Nuclear Information System (INIS)

Gawlik, D.; Robertson, T.

1992-06-01

An overview is given of those properties of the BER II research reactor which are important for carrying out irradiation experiments. The subsequent section describes the irradiation devices currently installed in the reactor, or which are under construction, and some of the experiments which can be conducted using them. The field of application of these experiments extends from the study of the metabolism of trace elements in man, employing a highly sensitive element analysis, via radiation damage of high-tech materials, to the identification of paintings of the old masters. The report concludes with a review of the technical details of the irradiation devices, giving information of interest for potential users. (orig.)

Total body irradiation with a reconditioned cobalt teletherapy unit.

Science.gov (United States)

Evans, Michael D C; Larouche, Renée-Xavière; Olivares, Marina; Léger, Pierre; Larkin, Joe; Freeman, Carolyn R; Podgorsak, Ervin B

2006-01-01

While the current trend in radiotherapy is to replace cobalt teletherapy units with more versatile and technologically advanced linear accelerators, there remain some useful applications for older cobalt units. The expansion of our radiotherapy department involved the decommissioning of an isocentric cobalt teletherapy unit and the replacement of a column-mounted 4-MV LINAC that has been used for total body irradiation (TBI). To continue offering TBI treatments, we converted the decommissioned cobalt unit into a dedicated fixed-field total body irradiator and installed it in an existing medium-energy LINAC bunker. This article describes the logistical and dosimetric aspects of bringing a reconditioned cobalt teletherapy unit into clinical service as a total body irradiator.

Modeling of irradiation embrittlement and annealing/recovery in pressure vessel steels