WorldWideScience

Sample records for irradiated pulse energy

  1. Evaluation of burnup characteristics and energy deposition during NSRR pulse irradiation tests on irradiated BWR fuels

    International Nuclear Information System (INIS)

    Nakamura, Takehiko; Yoshinaga, Makio

    2000-11-01

    Pulse irradiation tests of irradiated fuel are performed in the Nuclear Safety Research Reactor (NSRR) to investigate the fuel behavior under Reactivity Initiated Accident Conditions (RIA). The severity of the RIA is represented by energy deposition or peak fuel enthalpy during the power excursion. In case of the irradiated fuel tests, the energy deposition varies depending both on the amounts and distribution of residual fissile and neutron absorbing fission products generated during the base irradiation. Thus, proper fuel burnup characterization, especially for low enriched commercial fuels, is important, because plutonium (Pu) takes a large part of fissile and its generation depends on the neutron spectrum during the base irradiation. Fuel burnup calculations were conducted with ORIGEN2, RODBURN and SWAT codes for the BWR fuels tested in the NSRR. The calculation results were compared with the measured isotope concentrations and used for the NSRR neutron calculations to evaluate energy depositions of the test fuel. The comparison of the code calculations and the measurements revealed that the neutron spectrum change due to difference in void fraction altered Pu generation and energy deposition in the NSRR tests considerably. With the properly evaluated neutron spectrum, the combined burnup and NSRR neutron calculation gave reasonably good evaluation of the energy deposition. The calculations provided radial distributions of the fission product accumulation during the base irradiation and power distribution during the NSRR pulse irradiation, which were important for the evaluation of both burnup characteristics and fission gas release behavior. (author)

  2. Research on temperature characteristics of laser energy meter absorber irradiated by ms magnitude long pulse laser

    Science.gov (United States)

    Li, Nan; Qiao, Chunhong; Fan, Chengyu; Zhang, Jinghui; Yang, Gaochao

    2017-10-01

    The research on temperature characteristics for large-energy laser energy meter absorber is about continuous wave (CW) laser before. For the measuring requirements of millisecond magnitude long pulse laser energy, the temperature characteristics for absorber are numerically calculated and analyzed. In calculation, the temperature field distributions are described by heat conduction equations, and the metal cylinder cavity is used for absorber model. The results show that, the temperature of absorber inwall appears periodic oscillation with pulse structure, the oscillation period and amplitude respectively relate to the pulse repetition frequency and single pulse energy. With the wall deep increasing, the oscillation amplitude decreases rapidly. The temperature of absorber outerwall is without periodism, and rises gradually with time. The factors to affect the temperature rise of absorber are single pulse energy, pulse width and repetition frequency. When the laser irradiation stops, the temperature between absorber inwall and outerwall will reach agreement rapidly. After special technology processing to enhance the capacity of resisting laser damage for absorber inwall, the ms magnitude long pulse laser energy can be obtained with the method of measuring the temperature of absorber outerwall. Meanwhile, by optimization design of absorber structure, when the repetition frequency of ms magnitude pulse laser is less than 10Hz, the energy of every pulse for low repetition frequency pulse sequence can be measured. The work offers valuable references for the design of ms magnitude large-energy pulse laser energy meter.

  3. Degenerative and regenerative phenomena in pigmented rabbit irides following irradiation with the Xenon arc lamp at different pulse energies

    International Nuclear Information System (INIS)

    Wechsler, A.; Portmann, H.; Zypen, E. van der; Fauckhauser, F.

    1980-01-01

    The morphological condition of the pigmented rabbit iris following irradiation with a Xenon arclamp at four different pulse energies was analyzed. It was shown that: 1. There is a direct relationship between the applied pulse energy and the extent, as well as the rate, of secondary-degenerative transformations. 2. Secondary-degenerative and repair processes occur simultaneously. 3. As opposed to the primary damage event, secondary degeneration appears to progress from the back to the front of the iris. 4. As a rule, pulse energies of less than 1 Joule do not lead to secondary perforation of the iris. Fifteen weeks after the damage event, regeneration of connective tissue and the larger blood vessels, as well as of myelinated and unmyelinated nerves may be found. 5. The inducing factors, as well as those sustaining the process of secondary degeneration after irradiation of the rabbit iris with high pulse energies, cannot be explained on the basis of morphological findings alone. (orig.) [de

  4. Effect of Ge nanocluster assembly self-organization at pulsed irradiation by low-energy ions during heteroepitaxy on Si

    CERN Document Server

    Dvurechenskij, A V; Smagina, Z V

    2001-01-01

    Using the method of scanning microscopy one studied experimentally size distribution of Ge clusters formed in course of experiments of two types at Ge heteroepitaxy on Si(111): regular process of molecular-beam epitaxy (MBE); pulse irradiation by approx = 200 eV energy Ge ions. The experiments were conducted at 350 deg C temperature. Pulse irradiation by an ion beam during heteroepitaxy was detected to result in reduction of the average size of Ge clusters, in compacting of their density and in reduction of mean square deviation from the average value in contrast to similar values in experiments devoted to regular MBE

  5. Energy of a shock wave generated in different metals under irradiation by a high-power laser pulse

    International Nuclear Information System (INIS)

    Gus'kov, S. Yu.; Kasperczuk, A.; Pisarczyk, T.; Borodziuk, S.; Ullschmied, J.; Krousky, E.; Masek, K.; Pfeifer, M.; Skala, J.; Pisarczyk, P.

    2007-01-01

    The energies of a shock wave generated in different metals under irradiation by a high-power laser beam were determined experimentally. The experiments were performed with the use of targets prepared from a number of metals, such as aluminum, copper, silver and lead (which belong to different periods of the periodic table) under irradiation by pulses of the first and third harmonics of the PALS iodine laser at a radiation intensity of approximately 10 14 W/cm 2 . It was found that, for heavy metals, like for light solid materials, the fraction of laser radiation energy converted into the energy of a shock wave under irradiation by a laser pulse of the third harmonic considerably (by a factor of 2-3) exceeds the fraction of laser radiation energy converted under irradiation by a laser pulse of the first harmonic. The influence of radiation processes on the efficiency of conversion of the laser energy into the energy of the shock wave was analyzed

  6. HiRadMat: A high‐energy, pulsed beam, material irradiation facility

    CERN Multimedia

    Charitonidis, Nikolaos

    2016-01-01

    HiRadMat is a facility constructed in 2011, designed to provide high-intensity pulsed beams to an irradiation area where different material samples or accelerator components can be tested. The facility, located at the CERN SPS accelerator complex, uses a 440 GeV proton beam with a pulse length up to 7.2 μs and a maximum intensity up to 1E13 protons / pulse. The facility, a unique place for performing state-of-the art beam-to-material experiments, operates under transnational access and welcomes and financially supports, under certain conditions, experimental teams to perform their experiments.

  7. The impact of pulsed irradiation upon neutron activation calculations for inertial and magnetic fusion energy power plants

    International Nuclear Information System (INIS)

    Latkowski, J.F.; Sanz, J.; Vujic, J.L.

    1996-01-01

    Inertial fusion energy (IFE) and magnetic fusion energy (MFE) power plants will probably operate in a pulsed mode. The two different schemes, however, will have quite different time periods. Typical repetition rates for IFE power plants will be 1-5 Hz. MFE power plants will ramp up in current for about 1 hour, shut down for several minutes, and repeat the process. Traditionally, activation calculations for IFE and MFE power plants have assumed continuous operation and used either the ''steady state'' (SS) or ''equivalent steady state'' (ESS) approximations. It has been suggested recently that the SS and ESS methods may not yield accurate results for all radionuclides of interest. The present work expands that of Sisolak, et al. by applying their formulae to conditions which might be experienced in typical IFE and MFE power plants. In addition, complicated, multi-step reaction/decay chains are analyzed using an upgraded version of the ACAB radionuclide generation/depletion code. Our results indicate that the SS method is suitable for application to MFE power plant conditions. We also find that the ESS method generates acceptable results for radionuclides with half-lives more than a factor of three greater than the time between pulses. For components that are subject to 0.05 Hz (or more frequent) irradiation (such as coolant), use of the ESS method is recommended. For components or materials that are subject to less frequent irradiation (such as high-Z target materials), pulsed irradiation calculations should be used

  8. 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

  9. The energy distribution function of excess electrons trapped in the pulse irradiated low density polyethylene (LDPE)

    International Nuclear Information System (INIS)

    Wysocki, S.; Mazurek, L.; Karolczak, S.; Kroh, J.

    1995-01-01

    Distribution function D (E) of electrons trapped in irradiated LDPE was calculated on the basis of time resolved absorption spectra recorded at temperatures of 20-250 K. Variation of absorption spectra with time and temperature were observed and discussed in terms of simultaneous decay and relocation of electrons from shallow to deeper traps. Results obtained imply domination of trap limited transport for shallowly trapped electrons. For deeper traps, hopping mechanism is prevailing. (author)

  10. Arcing and rf signal generation during target irradiation by a high-energy, pulsed neutral particle beam

    International Nuclear Information System (INIS)

    Robiscoe, R.T.

    1988-02-01

    We present a theory describing the dynamics of arc discharges in bulk dielectric materials on board space-based vehicles. Such ''punch-through'' arcs can occur in target satellites irradiated by high-energy (250 MeV), pulsed (100 mA x 10 ms) neutral particle beams. We treat the arc as a capacitively limited avalanche current in the target dielectric material, and we find expressions for the arc duration, charge transport, currents, and discharge energy. These quantities are adjusted to be consistent with known scaling laws for the area of charge depleted by the arc. After a brief account of the statistical distribution of voltages at which the arc starts and stops, we calculate the signal strength and frequency spectrum of the electromagnetic radiation broadcast by the arc. We find that arcs from thick (/similar to/1 cm) targets can generate rf signals detectable up to 1000 km from the target, bu a radio receiver operating at frequency 80 MHz, bandwidth 100 kHz, and detection threshold -105 dBm. These thick-target arc signals are 10 to 20 dB above ambient noise at the receiver, and they provide target hit assessment if the signal spectrum can be sampled at several frequencies in the nominal range 30-200 MHz. Thin-target (/similar to/1 mm) arc signals are much weaker, but when they are detecable in conjunction with thick-target signals, target discrimination is possible by comparing the signal frequency spectra. 24 refs., 12 figs

  11. Fundamentals of laser pulse irradiation of silicon

    International Nuclear Information System (INIS)

    Rimini, E.; Baeri, P.; Russo, G.

    1985-01-01

    A computer model has been developed to describe the space and time evolution of carrier concentration, carrier energy and lattice temperature during nanosecond and picosecond laser pulse irradiation of Si single crystals. In particular the dynamic response has been evaluated for energy density of the ps laser pulse below and above the density threshold for surface melting. The obtained data allow a comparison with time-resolved reflectivity measurements reported in the literature. The available data are fitted by the computer model assuming a relaxation time for the energy transfer from the carriers to the lattice of 1 ps. The validity of the thermal model used to describe laser annealing in the nanosecond regime is assessed. (author)

  12. Influence of powerful pulses of laser irradiation on metallic films

    International Nuclear Information System (INIS)

    Besogonov, V.V.; Chudinov, V.G.

    1999-01-01

    The relaxation process of energy transferred by powerful pulses of laser irradiation to a superficial layer in metallic films has been investigated by the molecular dynamics technique. Beam energy transformation into mechanical energy of movement of irradiated atoms is shown to be possible due to changing pair interaction potentials. Variation of the Coulomb interaction screening of an ionic subsystem through the excitation of valence electrons is illustrated as major of the reasons for changing the potentials

  13. Closure phenomena in pinholes irradiated by Nd laser pulses

    Energy Technology Data Exchange (ETDEWEB)

    Auerbach, J.M.; Holmes, N.C.; Hunt, J.T.; Linford, G.J.

    1979-07-15

    An experimental investigation has been made on plasma closure in pinholes irradiated by Nd glass laser pulses; 300--500-..mu..m diam pinholes of various materials and thicknesses have been irradiated by 20--100-J 300-psec FWHM pulses on the Janus laser system. Calorimetry measurements have yielded data on pinhole energy transmission and intensity loading on the periphery of the pinhole. Ultrafast streak photography measurements indicate effective closure velocities of 2--5 x 10/sup 7/ cm/sec. Scattered light measurements have shown the transmission loss through a typical spatial filter configuration to be primarily refractive in nature.

  14. Energy and food irradiation

    International Nuclear Information System (INIS)

    Brynjolfsson, A.

    1978-01-01

    The energy used in food systems in the US amounts to about 16.5% of total US energy. An analysis has been made of the energy used in the many steps of the food-irradiation process. It is found that irradiation pasteurization uses only 21kJ/kg and radappertization 157kJ/kg, which is much less than the energy used in the other food processes. A comparison has also been made with other methods of preserving, distributing and preparing the meat for servings. It is found that the food irradiation can save significant amounts of energy. In the case of heat-sterilized and radiation-sterilized meats the largest fraction of the energy is used in the packaging, while in the frozen meats the largest energy consumption is by refrigeration in the distribution channels and in the home. (author)

  15. Morphological changes in skin tumors caused by pulsed laser irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Moskalik, K G; Lipova, V A; Neyshtadt, E L

    1979-01-01

    Morphological changes induced by treating melanomas, basaloma and flatcell skin cancers with a pulsed neodymium laser at 1060 nm, pulse length 1 msec and energy 250 to 500 J/cm/sup 2/, were studied using impressions and scrapings from the affected area. Nuclear pyknosis, nuclear and cellular elongation, vacuolization, frequent complete loss of cytoplasm, particulaly in the zone of direct irradiation, and loss of cellular structure were seen. These dystrophic changes increased with closeness to the zone of direct irradiation, culminating in necrosis. Formed and decomposed blood elements and melanin accumulated in the intracellular spaces, due to disruption of capillaries and small arteries and veins. Fewer and more aggregated melanoblasts were found after melanoma irradiation. Nuclear chromatin fusion, cytoplasmic changes and altered cell shape were observed. Basaloma cells were clustered and elongated after irradiation, with many fibrous structures and loss of cellular elements. Cytoplasmic vacuolization and lysis, bare nuclei, karyolysis, karyorrhexis and karyopyknosis were seen in corneous flat-cell cancer. In the few cases in which malignant cells were found under the scab from the first treatment the procedure was repeated. The morphological changes induced by pulsed laser irradiation are very similar to electrocoagulation necrosis, but are more localized. The ability of low and middle energy lasers to induce thrombosis and coagulation in vascular walls reduced the probability of hematogenic tumor cell dissemination. Cytological examination is highly effective in determining the degree of radical skin cancer healing due to laser treatment. 12 references, 2 figures.

  16. Energy distribution of the fast electron from Cu and CH targets irradiated with fs-laser pulses

    International Nuclear Information System (INIS)

    Cai Dafeng; Gu Yuqiu; Zheng Zhijian; Zhou Weimin; Jiao Chunye

    2014-01-01

    In order to investigate the effect of target's material on fast electron energy distribution, the energy distribution of fast electrons from the front and the rear of Cu and CH targets have been measured during the interaction of femtosecond laser-foil targets. The results show that the fast electron spectrums from the front of Cu and CH targets are similar, which show energy distribution of fast electrons depends very little on material of targets. The fast electron spectrums from the rear of Cu and CH targets are obviously dissimilar, which indicate a mighty effect of target material on fast electron transport. The fast electron spectrums from the Cu target is 'soften', which is due to electron recirculation and self-magnetic field produced by electrons transported in the target. The fast electron spectrums from the CH target is a Maxwellian distribution, which is due to collision effect when electrons transport in the target. (authors)

  17. 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

  18. Nanostructured surface processing by an intense pulsed ion beam irradiation

    International Nuclear Information System (INIS)

    Yatsuzuka, M.; Masuda, T.; Yamasaki, T.; Uchida, H.; Nobuhara, S.; Hashimoto, Y.; Yoshihara, Y.

    1997-01-01

    Metal surface modification by irradiating an intense pulsed ion beam (IPIB) with short pulse width has been studied experimentally. An IPIB irradiation to a target leads to rapid heating above its melting point. After the beam is turned off, the heated region is immediately cooled by thermal conduction at a cooling rate of typically 10 10 K/s. This rapid cooling and resolidification results in generation of nanostructured phase in the top of surface. The typical hydrogen IPIB parameters are 200 kV of energy, 500 A/cm 2 of current density and 70 ns of pulsewidth. The IPIB was irradiated on a pure titanium to generate nanocrystalline phase. The IPIB-irradiated surface was examined with X-ray diffraction, SEM, and HR-TEM. The randomly oriented lattice fringes as well as a halo diffraction pattern are observed in the HR-TEM micrograph of IPIB-irradiated titanium. The average grain size is found to be 32 nanometers

  19. High energy HF pulsed lasers

    International Nuclear Information System (INIS)

    Patterson, E.L.; Gerber, R.A.

    1976-01-01

    Recent experiments show that pulsed HF lasers are capable of producing high energy with good efficiency. Preliminary experiments show that the laser radiation from the high-gain medium can be controlled with a low-power probe laser beam or with low-level feedback. These results indicate that the HF laser may have potential for second-generation laser fusion experiments

  20. Thermal shock testing of ceramics with pulsed laser irradiation

    International Nuclear Information System (INIS)

    Benz, R.; Naoumidis, A.; Nickel, H.

    1986-04-01

    Arguments are presented showing that the resistance to thermal stressing (''thermal shock'') under pulsed thermal energy deposition by various kinds of beam irradiations is approximately proportional to Φ a √tp, where Φ a is the absorbed power density and tp is the pulse length, under conditions of diffusivity controlled spreading of heat. In practical beam irradiation testing, incident power density, Φ, is reported. To evaluate the usefulness of Φ√tp as an approximation to Φ a √tp, damage threshold values are reviewed for different kinds of beams (electron, proton, and laser) for a range of tp values 5x10 -6 to 2 s. Ruby laser beam irradiation tests were made on the following ceramics: AlN, BN, graphite, αSiC, β-SiC coated graphites, (α+β)Si 3 N 4 , CVD (chemical vapor deposition) TiC coated graphite, CVD TiC coated Mo, and CVD TiN coated IN 625. The identified failure mechanisms are: 1. plastic flow followed by tensile and bend fracturing, 2. chemical decomposition, 3. melting, and 4. loss by thermal spallation. In view of the theoretical approximations and the neglect of reflection losses there is reasonable accord between the damage threshold Φ√tp values from the laser, electron, and proton beam tests. (orig./IHOE)

  1. SBS pulse compression for excimer inertial fusion energy drivers

    Energy Technology Data Exchange (ETDEWEB)

    Linford, G.J. [TRW Space and Electronics Group, Redondo Beach, CA (United States). Space and Technology Div.

    1994-12-31

    A key requirement for the development of commercial fusion power plants utilizing inertial confinement fusion (ICF) as a source of thermonuclear power is the availability of reliable, efficient laser drivers. These laser drivers must be capable of delivering UV optical pulses having energies of the order of 5MJ to cryogenic deuterium-tritium (D/T) ICF targets. The current requirements for laser ICF target irradiation specify the laser wavelength, {lambda} ca. 250 nm, pulse duration, {tau}{sub p} ca. 6 ns, bandwidth, {Delta}{lambda} ca. 0.1 nm, polarization state, etc. Excimer lasers are a leading candidate to fill these demanding ICF driver requirements. However, since excimer lasers are not storage lasers, the excimer laser pulse duration, {tau}{sub pp}, is determined primarily by the length of the excitation pulse delivered to the excimer laser amplifier. Pulsed power associated with efficiently generating excimer laser pulses has a time constant, {tau}{sub pp} which falls in the range, 30 {tau}{sub p}<{tau}{sub pp}<100{tau}{sub p}. As a consequence, pulse compression is needed to convert the long excimer laser pulses to pulses of duration {tau}{sub p}. These main ICF driver pulses require, in addition, longer, lower power precursor pulses delivered to the ICF target before the arrival of the main pulse. Although both linear and non-linear optical (NLO) pulse compression techniques have been developed, computer simulations have shown that a ``chirped,`` self-seeded, stimulated Brillouin scattering (SBS) pulse compressor cell using SF{sub 6} at a density, {rho} ca. 1 amagat can efficiently compress krypton fluoride (KrF) laser pulses at {lambda}=248 nm. In order to avoid the generation of output pulses substantially shorter than {tau}{sub p}, the optical power in the chirped input SBS ``seed`` beams was ramped. Compressed pulse conversion efficiencies of up to 68% were calculated for output pulse durations of {tau}{sub p} ca. ns.

  2. SBS pulse compression for excimer inertial fusion energy drivers

    International Nuclear Information System (INIS)

    Linford, G.J.

    1994-01-01

    A key requirement for the development of commercial fusion power plants utilizing inertial confinement fusion (ICF) as a source of thermonuclear power is the availability of reliable, efficient laser drivers. These laser drivers must be capable of delivering UV optical pulses having energies of the order of 5MJ to cryogenic deuterium-tritium (D/T) ICF targets. The current requirements for laser ICF target irradiation specify the laser wavelength, λ ca. 250 nm, pulse duration, τ p ca. 6 ns, bandwidth, Δλ ca. 0.1 nm, polarization state, etc. Excimer lasers are a leading candidate to fill these demanding ICF driver requirements. However, since excimer lasers are not storage lasers, the excimer laser pulse duration, τ pp , is determined primarily by the length of the excitation pulse delivered to the excimer laser amplifier. Pulsed power associated with efficiently generating excimer laser pulses has a time constant, τ pp which falls in the range, 30 τ p pp p . As a consequence, pulse compression is needed to convert the long excimer laser pulses to pulses of duration τ p . These main ICF driver pulses require, in addition, longer, lower power precursor pulses delivered to the ICF target before the arrival of the main pulse. Although both linear and non-linear optical (NLO) pulse compression techniques have been developed, computer simulations have shown that a ''chirped,'' self-seeded, stimulated Brillouin scattering (SBS) pulse compressor cell using SF 6 at a density, ρ ca. 1 amagat can efficiently compress krypton fluoride (KrF) laser pulses at λ=248 nm. In order to avoid the generation of output pulses substantially shorter than τ p , the optical power in the chirped input SBS ''seed'' beams was ramped. Compressed pulse conversion efficiencies of up to 68% were calculated for output pulse durations of τ p ca. ns

  3. 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.

  4. Surface damage characteristics of CFC and tungsten with repetitive ELM-like pulsed plasma irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Kikuchi, Y., E-mail: ykikuchi@eng.u-hyogo.ac.jp [Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji, 671-2280 Hyogo (Japan); Nishijima, D. [Center for Energy Research, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0417 (United States); Nakatsuka, M.; Ando, K.; Higashi, T.; Ueno, Y.; Ishihara, M.; Shoda, K.; Nagata, M. [Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji, 671-2280 Hyogo (Japan); Kawai, T.; Ueda, Y. [Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Fukumoto, N. [Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji, 671-2280 Hyogo (Japan); Doerner, R.P. [Center for Energy Research, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0417 (United States)

    2011-08-01

    Surface damage of carbon fiber composite (CFC) and tungsten (W) due to repetitive ELM-like pulsed plasma irradiation has been investigated by using a magnetized coaxial plasma gun. CX2002U CFC and stress-relieved W samples were exposed to repetitive pulsed deuterium plasmas with duration of {approx}0.5 ms, incident ion energy of {approx}30 eV, and surface absorbed energy density of {approx}0.3-0.7 MJ/m{sup 2}. Bright spots on a CFC surface during pulsed plasma exposures were clearly observed with a high-speed camera, indicating a local surface heating. No melting of a W surface was observed under a single plasma pulse exposure at energy density of {approx}0.7 MJ/m{sup 2}, although cracks were formed. Cracking of the W surface grew with repetitive pulsed plasma exposures. Subsequently, the surface melted due to localized heat absorption.

  5. Pulse laser irradiation into superconducting MgB2 detector

    International Nuclear Information System (INIS)

    Fujiwara, Daisuke; Miki, Shigehito; Satoh, Kazuo; Yotsuya, Tsutomu; Shimakage, Hisashi; Wang, Zhen; Okayasu, Satoru; Katagiri, Masaki; Machida, Masahiko; Kato, Masaru; Ishida, Takekazu

    2005-01-01

    We performed 20-ps pulse laser irradiation experiments on a MgB 2 neutron detector to know a thermal-relaxation process for designing a MgB 2 neutron detector. The membrane-type structured MgB 2 device was fabricated to minimize the heat capacity of sensing part of a detector as well as to enhance its sensitivity. We successfully observed a thermal-relaxation signal resulting from pulse laser irradiation by developing a detection circuit. The response time was faster than 1 μs, meaning that the detector would be capable of counting neutrons at a rate of more than 10 6 events per second

  6. Investigation of plasma stream collision produced by thin films irradiated by powerful pulsed electron beam

    International Nuclear Information System (INIS)

    Efremov, V P; Demidov, B A; Ivkin, M V; Mescheryakov, A N; Petrov, V A; Potapenko, A I

    2006-01-01

    Collision of fast plasma streams in vacuum is investigated. Plasma streams were produced by irradiation of thin foils with a powerful pulsed electron beam. Interaction of the plasma flows was studied by using frame and streak cameras. One-dimensional numerical simulation was carried out. Application of this method for porous ICF targets and high-energy physics is discussed

  7. Viscometric and Pulsed Photostimulated Luminescence Properties of Irradiated Glutinous Rice

    International Nuclear Information System (INIS)

    Yang, J.S.; Yi, S.D.; Chang, K.S.; Oh, M.J.

    2004-01-01

    This study was carried out to establish a method for the detection of irradiated glutinous rice by measuring pulsed photostimulated luminescence (PPSL) and viscometric properties. Viscosity was determined using a Brookfield DV-III rotation viscometer at 3 deg. C and measured at 30, 60, 90, 120, 150, 180, and 210 rpm. All irradiated samples indicated a decrease in viscosity with increasing stirring speeds (rpm) and irradiation doses. Treatments with 2∼5 kGy significantly decreased the viscosity. The photon counts of the irradiated glutinous rice were measured by PPSL and the photon counts of the non-irradiated and irradiated glutinous rice measured immediately after irradiation exhibited an increase with increasing irradiation dose. The photon counts of irradiated glutinous rice almost disappeared with the lapse of time when stored under normal room conditions, but was still possible to detect after 12 months of darkroom storage. Consequently, these results indicate that the detection of irradiated glutinous rice is possible by both viscometric and PPSL methods

  8. Effects of pulsed dual-ion irradiation of microstructural development

    International Nuclear Information System (INIS)

    Packan, N.H.

    1981-01-01

    The effect of pulsed irradiation on the development of microstructure during Ni ion bombardment has been investigated in a simple austenitic alloy similar to type 316 stainless steel. Bombardment conditions were 10 dpa, 940 K, pulsing with equal on/off times of either 0.5 or 60 s, and the addition of 20 appM He/dpa to some specimens either by room temperature preimplantation or by dual-beam coimplantation. Particular care was taken to minimize thermal pulses from beam heating (to 0 C). The results show that pulsing has a subtle influence, and the effects on specific cavity parameters are complex. Pulsing produced a small increase in swelling in the helium-free case, but a slight decrease for helium-implanted specimens, and it seems to have counteracted the usual stimulative effects of helium on cavity nucleation

  9. Pulsed irradiation of enriched UO{sub 2} in the Annular Core Pulse Reactor (ACPR)

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, T R; Lucoff, D M; Reil, K O; Croucher, D W [Sandia Laboratories (United States)

    1974-07-01

    A series of experiments have been conducted in the Annular Core Pulse Reactor (ACPR) to determine the energy deposition and behavior of enriched UO{sub 2} under pulse conditions. In the experiment single unirradiated pellets with enrichments up to 25 percent were pulse heated to melt temperatures. Temperature and fission product inventory measurements were made and compared with neutron transport calculations. (author)

  10. Inactivation of Lactobacillus plantarum by pulsed-microwave irradiation

    International Nuclear Information System (INIS)

    Shin, J.K.; Pyun, Y.R.

    1997-01-01

    Suspensions of Lactobacillus plantarum cells were subjected to either conventional heating, continuous microwave (CW) or pulsed microwave (PW) irradiation at 50 degrees C for 30 min. Samples exposed to PW showed greater reductions (2 approximately 4 log) in survival counts than those treated with either conventional heating or CW irradiation. As exposure time increased, PW resulted in a remarkable increase in 260 nm-absorbing compounds that leaked into the suspending menstruum, as compared to CW or conventional heating, indicating that PW irradiated cells were the most injured. The growth of PW irradiated cells was delayed about 24h and the final acidity of the culture broth was about 60 approximately 80% that of other cells treated with conventional heating or CW irradiation

  11. Thermal conductivity contrast measurement of Fused Silica exposed to low-energy femtosecond laser pulses

    NARCIS (Netherlands)

    Bellouard, Y.J.; Dugan, M.; Said, A.A.; Bado, P.

    2006-01-01

    Femtosecond laser irradiation has various noticeable effects on fused silica. Of particular interest, pulses with energy levels below the ablation threshold can locally increase the refractive index and the material etching selectivity to hydrofluoric acid. The mechanism responsible for these

  12. Electromagnetic or other directed energy pulse launcher

    Science.gov (United States)

    Ziolkowski, Richard W.

    1990-01-01

    The physical realization of new solutions of wave propagation equations, such as Maxwell's equations and the scaler wave equation, produces localized pulses of wave energy such as electromagnetic or acoustic energy which propagate over long distances without divergence. The pulses are produced by driving each element of an array of radiating sources with a particular drive function so that the resultant localized packet of energy closely approximates the exact solutions and behaves the same.

  13. Model of defect reactions and the influence of clustering in pulse-neutron-irradiated Si

    International Nuclear Information System (INIS)

    Myers, S. M.; Cooper, P. J.; Wampler, W. R.

    2008-01-01

    Transient reactions among irradiation defects, dopants, impurities, and carriers in pulse-neutron-irradiated Si were modeled taking into account the clustering of the primal defects in recoil cascades. Continuum equations describing the diffusion, field drift, and reactions of relevant species were numerically solved for a submicrometer spherical volume, within which the starting radial distributions of defects could be varied in accord with the degree of clustering. The radial profiles corresponding to neutron irradiation were chosen through pair-correlation-function analysis of vacancy and interstitial distributions obtained from the binary-collision code MARLOWE, using a spectrum of primary recoil energies computed for a fast-burst fission reactor. Model predictions of transient behavior were compared with a variety of experimental results from irradiated bulk Si, solar cells, and bipolar-junction transistors. The influence of defect clustering during neutron bombardment was further distinguished through contrast with electron irradiation, where the primal point defects are more uniformly dispersed

  14. Ignitor electrode system design for the pulses electron irradiators device

    International Nuclear Information System (INIS)

    Lely Susita RM; Ihwanul Aziz

    2016-01-01

    The designed ignitor electrode system is a system used to initiate the plasma discharge. It consists of two pieces which are placed on both side of the plasma vessel. Each of the ignitor electrode system consists of a cathode, an anode and insulator between the cathode and the anode. The best cathode material for ignitor electrode system is Mg due to its lowest ion erosion rate (γi =11.7 μg/C) and its low cohesive energy (1.51 eV). The specifications of ignitor electrode system designed for the pulse electron irradiators is as follow: Mg cathode materials in the form of rod having a diameter of 6.35 mm and length of 76.75 mm. Anode material are made of non magnetic of SS 304 cylinder shaped with an outer diameter of 88.53 mm, an inner diameter of 81.53 mm and a thickness of 3.50 mm. Insulating material between the cathode and the anode is made of teflon cylinder shaped, outer diameter of 9.50 mm, an inner diameter of 6.35 mm and a length of 30 mm. Based on the ignitor electrode system design, the next step is construction and function test of the ignitor electrode system. (author)

  15. Pulsed power liner for PLT energy systems

    International Nuclear Information System (INIS)

    Armellino, C.A.; Bronner, G.; Murray, J.G.

    1975-01-01

    PLT is Princeton University's latest Tokamak machine in the controlled thermonuclear fusion research effort. The OH (ohmic heating) and SF (shaping field) systems for the machine place a very high energy pulsed current load on the AC line feeding them. This paper describes the two systems and the steps taken to insure minimum effect on line regulation during the pulsed operation

  16. 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

  17. Formation of nanograting in fused silica by temporally delayed femtosecond double-pulse irradiation

    Science.gov (United States)

    Wang, Haodong; Song, Juan; Li, Qin; Zeng, Xianglong; Dai, Ye

    2018-04-01

    A 1 kHz femtosecond double-pulse sequence irradiation is used to study the temporal evolution of nanograting in fused silica by controlling the delay times and polarization combinations of two independent beams from a Mach–Zehnder interferometer. A lateral laser-scan experiment with speed at 5 µm s‑1 and each pulse energy of 1 µJ is firstly performed with the delay time from sub-picosecond to 10 ps, and then the written nanostructures are systematically studied under a cross-polarized microscope because the intensity of birefringence signal nearly corresponds to optical retardance and development level of the induced nanograting. The trend shows that the induced nanogratings can continue developing with a decrease of delay time in the case of the linear polarization pulse arriving before. In another vertical laser-scan experiment at the same speed and pulse energy, the morphologies of nanogratings embedded in the lines are characterized by scanning electron microscope after mechanical polishing and chemical etching. The self-organized patterns have a commonly spatial period of 200–300 nm and the orientation is always perpendicular to the polarization of the first laser pulse, and the second pulse in each sequence seems to promote the as-formed nanograting developing further even if the polarized direction is different from the previous pulse. These new findings verify again that a localized memory effect can make positive feedback to reinforce the patterned nanostripes. In that process, the impact ionization from the seed electrons left by the first pulse excitation and the photoionization of self-trapped excitons with lower ionization threshold results in an increase of the re-excited carriers during the second pulse irradiation and the subsequent development of the as-formed nanograting. Our result provides further proofs for understanding the physical mechanism of nanograting strongly connection with the interplay on multiple ionization channels.

  18. Realization of double-pulse laser irradiating scheme for laser ion sources

    International Nuclear Information System (INIS)

    Li Zhangmin; Jin Qianyu; Liu Wei; Zhang Junjie; Sha Shan; Zhao Huanyu; Sun Liangting; Zhang Xuezhen; Zhao Hongwei

    2015-01-01

    A double-pulse laser irradiating scheme has been designed and established for the production of highly charged ion beams at Institute of Modern Physics (IMP), Chinese Academy of Sciences. The laser beam output by a Nd : YAG laser is split and combined by a double of beam splitters, between which the split laser beams are transmitted along different optical paths to get certain time delay between each other. With the help of a quarter-wave plate before the first splitter, the energy ratio between the two laser pulses can be adjusted between 3 : 8 to 8 : 3. To testify its feasibility, a preliminary experiment was carried out with the new-developed double-pulse irradiating scheme to produce highly charged carbon ions. Comparing the results with those got from the previous single-pulse irradiating scheme, the differences in the time structure and Charge State Distribution (CSD) of the ion pulse were observed, but its mechanisms and optimization require further studies. (authors)

  19. Effect on structure and mechanical property of tungsten irradiated by high intensity pulsed ion beam

    Science.gov (United States)

    Mei, Xianxiu; Zhang, Xiaonan; Liu, Xiaofei; Wang, Younian

    2017-09-01

    The anti-thermal radiation performance of tungsten was investigated by high intensity pulsed ion beam technology. The ion beam was mainly composed of Cn+ (70%) and H+ (30%) at an acceleration voltage of 250 kV under different energy densities for different number of pulses. GIXRD analysis showed that no obvious phase structural changes occurred on the tungsten, and microstress generated. SEM analysis exhibited that there was no apparent irradiation damage on the surface of tungsten at the low irradiation frequency (3 times and 10 times) and at the low energy density (0.25 J/cm2 and 0.7 J/cm2). Cracks appeared on the surface of tungsten after 100-time and 300-time irradiation. Shedding phenomenon even appeared on the surface of tungsten at the energy densities of 1.4 J/cm2 and 2.0 J/cm2. The surface nano-hardness of tungsten decreased with the increase of the pulse times and the energy density. The tungsten has good anti-thermal radiation properties under certain heat load environment.

  20. Morphological changes in skeletal muscle after irradiation with nano- and microsecond laser pulses

    International Nuclear Information System (INIS)

    Gratzl, T.

    1995-09-01

    For therapeutic application of laser light it is necessary to minimize defects in the nonirradiated tissue. These defects depend on the primary mechanism of interaction between tissue and laser light. Three experiments were performed to distinguish between mechanical and thermal effects of nano- and microsecond laser pulses in skeletal muscle of the rat. The light, transmission and scanning electron microscopes were used. Laser pulses were applied to unfixed muscle immediately after dissection. A Nd-YAG laser (wavelength 1064 nm; pulse repetition rate 10s -1 ; beam diameter 9 mm; pulse-energy 340 mJ) was used in the flashlamp-pulsed mode (pulse duration 100 μs) and the Q-switched mode (pulse duration 8 ns). When focused 2 mm below the tissue surface in the μs-experiments (100 μs) 200 laser pulses produced a small crater. The defective region after irradiation can be divided under the light microscope into four zones surrounding the crater. The innermost zone I showed vacuoles in the intensively stained muscle cells. In the next zone II the myofibrils were displaced and torn apart. Zone III is a sharply bordered, intensively stained region. The muscle cells in zone IV are contracted. All these tissue effects were thermally induced. When focused 4 mm below the tissue surface, the μs-pulses produced an expansion of the irradiated region, while leaving the surface intact. Here, only the features of zones II to IV were seen. In the spallation experiments muscle samples were placed on metal foil. The foil itself was dipped into water. A single laser pulse (8 ns) was directed at the underside of the foil. Only the pressure wave passed through the sample and was reflected on the muscle surface in a stretch wave. Tissue damage by mechanical action occurs inside the sample. Muscle fibers are torn apart and myofibrils are displaced. In the ns-experiments the mechanical action of a single ns pulse (8 ns) produced a crater. Only zones I and IV developed. With 50 to 100

  1. Design of electron detection system for pulse electron irradiator

    International Nuclear Information System (INIS)

    Anjar Anggraini H; Agus Purwadi; Lely Susita RM; Bambang Siswanto; Agus Wijayanto

    2016-01-01

    Design of electron detection system for pulse electron irradiator has been conducted on the Plasma Cathode Electron Source by Rogowski coil technique. Rogowski coil has ability to capture the induced magnetic field of the electric current, subsequent induced magnetic field will provide voltage after passing integrator. This diagnostic used combination of copper wire, ferrite and RC integrator. The design depends on the pulse width and the value of plasma current that passes through the coil, thus the number of windings, coil area and integrator can be designed. For plasma spots current of IDPS expected to be 10 A and pulse width 10 μs the Rogowski coil using MnZn ferrite with inductance L = 0.275 mH and permeability μr = 200 H/m. For the current of plasma arc ADPS expected to be 100 A and pulse width 100 μs by using inductance L=1.9634 mH and permeability μr = 6256 H/m. Electron current in extraction system expected to be 30 A and pulse width 100 μs the Rogowski coil using inductance L=51.749 mH and permeability μr= 4987 H/m. Design integrator used is the type of RC integrator. (author)

  2. Detection of Irradiated Korean Wheat Flour by Viscosity and Pulsed Photostimulated Luminescence (PPSL) Methods

    International Nuclear Information System (INIS)

    Yi, S.D.; Chang, K.S.; Oh, M.J.

    2005-01-01

    This study was carried out to establish methods for irradiation detection of irradiation in Korean wheat flour by pulsed photostimulated luminescence (PPSL) and viscometric methods. The photon counts of the irradiated Korean wheat flour measured by PPSL immediately after irradiation increased with increasing irradiation dose. The photon counts in the irradiated Korean wheat flour almost disappeared with lapse of time after storage in normal room conditions, but irradiation detection was still possible after 6 months in darkroom conditions

  3. Atom transfer radical polymerization of styrene under pulsed microwave irradiation

    International Nuclear Information System (INIS)

    Cheng Zhenping; Zhu Xiulin; Zhou Nianchen; Zhu Jian; Zhang Zhengbiao

    2005-01-01

    A homogeneous solution atom transfer radical polymerization (ATRP) and reverse atom transfer radical polymerization (RATRP) of styrene (St) in N,N-dimethylformamide (DMF) were successfully carried out under pulsed microwave irradiation (PMI), using 1-bromo-1-phenylethane (1-PEBr)/CuCl/N,N,N',N'',N''-pentamethyldiethylenetriamine (PMDETA) as an initiating system at 85 deg. C and 2,2'-azo-bis-isobutyrontrile (AIBN)/CuCl 2 /PMDETA as an initiating system at 95 deg. C, respectively. The polymerization rates under PMI were greatly increased in comparison with those under identical conventional heating (CH)

  4. Microwave radiation mechanism in a pulse-laser-irradiated Cu foil target revisited

    International Nuclear Information System (INIS)

    Chen Ziyu; Li Jianfeng; Li Jun; Peng Qixian

    2011-01-01

    The microwave radiation mechanism in a Cu-based foil target irradiated by an intense laser pulse has been investigated. Microwave emission in the frequency range 0.5-4 GHz has been observed from a 200 ps laser pulse of intensity about 10 12 W cm -2 normally incident on the target surface. The total microwave power and energy emitted from the interaction were found to be about 0.4 W and 2 nJ, respectively, corresponding to an efficiency of coupling laser energy to microwave energy of 2x10 -8 . The result agrees well with quadrupole radiation calculated based on a circuit model of a laser plasma, which indicates that the radiative process can be explained by magnetic dipole or electric quadrupole radiation from the laser-produced symmetric poloidal current distribution at the plasma-target interface.

  5. Microwave radiation mechanism in a pulse-laser-irradiated Cu foil target revisited

    Energy Technology Data Exchange (ETDEWEB)

    Chen Ziyu; Li Jianfeng; Li Jun; Peng Qixian, E-mail: ziyuch@gmail.com [Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang 621900 (China)

    2011-05-01

    The microwave radiation mechanism in a Cu-based foil target irradiated by an intense laser pulse has been investigated. Microwave emission in the frequency range 0.5-4 GHz has been observed from a 200 ps laser pulse of intensity about 10{sup 12} W cm{sup -2} normally incident on the target surface. The total microwave power and energy emitted from the interaction were found to be about 0.4 W and 2 nJ, respectively, corresponding to an efficiency of coupling laser energy to microwave energy of 2x10{sup -8}. The result agrees well with quadrupole radiation calculated based on a circuit model of a laser plasma, which indicates that the radiative process can be explained by magnetic dipole or electric quadrupole radiation from the laser-produced symmetric poloidal current distribution at the plasma-target interface.

  6. Determination of ablation threshold for composite resins and amalgam irradiated with femtosecond laser pulses

    International Nuclear Information System (INIS)

    Freitas, A Z; Samad, R E; Zezell, D M; Vieira Jr, N D; Freschi, L R; Gouw-Soares, S C

    2010-01-01

    The use of laser for caries removal and cavity preparation is already a reality in the dental clinic. The objective of the present study was to consider the viability of ultrashort laser pulses for restorative material selective removal, by determining the ablation threshold fluence for composite resins and amalgam irradiated with femtosecond laser pulses. Lasers pulses centered at 830 nm with 50 fs of duration and 1 kHz of repetition rate, with energies in the range of 300 to 770 μJ were used to irradiate the samples. The samples were irradiated using two different geometrical methods for ablation threshold fluence determinations and the volume ablation was measured by optical coherence tomography. The shape of the ablated surfaces were analyzed by optical microscopy and scanning electron microscopy. The determined ablation threshold fluence is 0.35 J/cm 2 for the composite resins Z-100 and Z-350, and 0.25 J/cm 2 for the amalgam. These values are half of the value for enamel in this temporal regime. Thermal damages were not observed in the samples. Using the OCT technique (optical coherence tomography) was possible to determine the ablated volume and the total mass removed

  7. Simulation analysis of impulse characteristics of space debris irradiated by multi-pulse laser

    Science.gov (United States)

    Lin, Zhengguo; Jin, Xing; Chang, Hao; You, Xiangyu

    2018-02-01

    Cleaning space debris with laser is a hot topic in the field of space security research. Impulse characteristics are the basis of cleaning space debris with laser. In order to study the impulse characteristics of rotating irregular space debris irradiated by multi-pulse laser, the impulse calculation method of rotating space debris irradiated by multi-pulse laser is established based on the area matrix method. The calculation method of impulse and impulsive moment under multi-pulse irradiation is given. The calculation process of total impulse under multi-pulse irradiation is analyzed. With a typical non-planar space debris (cube) as example, the impulse characteristics of space debris irradiated by multi-pulse laser are simulated and analyzed. The effects of initial angular velocity, spot size and pulse frequency on impulse characteristics are investigated.

  8. Criteria for formation of low-frequency sound under wide-aperture repetitively pulsed laser irradiation of solids

    International Nuclear Information System (INIS)

    Tishchenko, V N; Posukh, V G; Gulidov, A I; Zapryagaev, V I; Pavlov, A A; Boyarintsev, Ye L; Golubev, M P; Kavun, I N; Melekhov, A V; Golobokova, L S; Miroshnichenko, I B; Pavlov, Al A; Shmakov, A S

    2011-01-01

    The criteria for merging shock waves formed by optical breakdowns on the surface of solids have been investigated. Targets made of different materials were successively irradiated by two CO 2 -laser pulses with energies up to 200 J and a duration of ∼1 μs. It is shown that the criteria under consideration can be applied to different targets and irradiation regimes and make it possible to calculate the parameters of repetitively pulsed laser radiation that are necessary to generate low-frequency sound and ultrasound in air.

  9. Laser polarization dependence of proton emission from a thin foil target irradiated by a 70 fs, intense laser pulse

    International Nuclear Information System (INIS)

    Fukumi, A.; Nishiuchi, M.; Daido, H.; Li, Z.; Sagisaka, A.; Ogura, K.; Orimo, S.; Kado, M.; Hayashi, Y.; Mori, M.; Bulanov, S.V.; Esirkepov, T.; Nemoto, K.; Oishi, Y.; Nayuki, T.; Fujii, T.; Noda, A.; Nakamura, S.

    2005-01-01

    A study of proton emission from a 3-μm-thick Ta foil target irradiated by p-, s-, and circularly polarized laser pulses with respect to the target plane has been carried out. Protons with energies up to 880 keV were observed in the target normal direction under the irradiation by the p-polarized laser pulse, which yielded the highest efficiency for proton emission. In contrast, s- and circularly polarized laser pulses gave the maximum energies of 610 and 680 keV, respectively. The difference in the maximum energy between the p- and s-polarized cases was associated with the difference between the sheath fields estimated from electron spectra

  10. Charge collection and charge pulse formation in highly irradiated silicon planar detectors

    International Nuclear Information System (INIS)

    Dezillie, B.; Li, Z.; Eremin, V.

    1998-06-01

    The interpretation of experimental data and predictions for future experiments for high-energy physics have been based on conventional methods like capacitance versus voltage (C-V) measurements. Experiments carried out on highly irradiated detectors show that the kinetics of the charge collection and the dependence of the charge pulse amplitude on the applied bias are deviated too far from those predicted by the conventional methods. The described results show that in highly irradiated detectors, at a bias lower than the real full depletion voltage (V fd ), the kinetics of the charge collection (Q) contains a fast and a slow component. At V = V fd *, which is the full depletion voltage traditionally determined by the extrapolation of the fast component amplitude of q versus bias to the maximum value or from the standard C-V measurements, the pulse has a slow component with significant amplitude. This slow component can only be eliminated by applying additional bias that amounts to the real full depletion voltage (V fd ) or more. The above mentioned regularities are explained in this paper in terms of a model of an irradiated detector with multiple regions. This model allows one to use C-V, in a modified way, as well as TChT (transient charge technique) measurements to determine the V fd for highly irradiated detectors

  11. Mechanical response of agar gel irradiated with Nd:YAG nanosecond laser pulses

    Science.gov (United States)

    Pérez-Gutiérrez, Francisco G.; Evans, Rodger; Camacho-López, Santiago; Aguilar, Guillermo

    2010-02-01

    Nanosecond long laser pulses are used in medical applications where precise tissue ablation with minimal thermal and mechanical collateral damage is required. When a laser pulse is incident on a material, optical energy will be absorbed by a combination of linear and nonlinear absorption according to both: laser light intensity and material properties. In the case of water or gels, the first results in heat generation and thermoelastic expansion; while the second results in an expanding plasma formation that launches a shock wave and a cavitation/boiling bubble. Plasma formation due to nonlinear absorption of nanosecond laser pulses is originated by a combination of multiphoton ionization and thermionic emission of free electrons, which is enhanced when the material has high linear absorption coefficient. In this work, we present measurements of pressure transients originated when 6 ns laser pulses are incident on agar gels with varying linear absorption coefficient, mechanical properties and irradiation geometry using laser radiant exposures above threshold for bubble formation. The underlying hypothesis is that pressure transients are composed of the superposition of both: shock wave originated by hot expanding plasma resulting from nonlinear absorption of optical energy and, thermoelastic expansion originated by heat generation due to linear absorption of optical energy. The objective of this work is to evaluate the relative contribution of each absorption mechanism to mechanical effects in agar gel. Real time pressure transients are recorded with PVDF piezoelectric sensors and time-resilved imaging from 50 μm to 10 mm away from focal point.

  12. Polymerization of polyethers initiated by irradiation with high power pulsed electron beams

    International Nuclear Information System (INIS)

    Gerber, V.D.; Tolkachev, V.S.; Chmukh, V.N.

    1982-01-01

    Air oxygen effect on thin-layer polymerization of polyethers, initiated by irradiation with powerful pulse electron beams is studied using the method of IR-spectrophotometry. The analysis of experimental data has shown that in polyether surface layer polymerization is suppressed by oxygen, concentration of which in the layer remains stable at the expense of diffusion from air during two consequent irradiation pulses

  13. High energy electron irradiation of flowable materials

    International Nuclear Information System (INIS)

    Offermann, B.P.

    1975-01-01

    In order to efficiently irradiate a flowable material with high energy electrons, a hollow body is disposed in a container for the material and the material is caused to flow in the form of a thin layer across a surface of the body from or to the interior of the container while the material flowing across the body surface is irradiated. (U.S.)

  14. Thermodynamic pathways to melting, ablation, and solidification in absorbing solids under pulsed laser irradiation

    International Nuclear Information System (INIS)

    Lorazo, Patrick; Lewis, Laurent J.; Meunier, Michel

    2006-01-01

    The thermodynamic pathways involved in laser irradiation of absorbing solids are investigated in silicon for pulse durations of 500 fs and 100 ps. This is achieved by accounting for carrier and atom dynamics within a combined Monte Carlo and molecular-dynamics scheme and simultaneously tracking the time evolution of the irradiated material in ρ-T-P space. Our simulations reveal thermal changes in long-range order and state of aggregation driven, in most cases, by nonequilibrium states of rapidly heated or promptly cooled matter. Under femtosecond irradiation near the ablation threshold, the system is originally pulled to a near-critical state following rapid ( -12 s) disordering of the mechanically unstable crystal and isochoric heating of the resulting metallic liquid. The latter is then adiabatically cooled to the liquid-vapor regime where phase explosion of the subcritical, superheated melt is initiated by a direct conversion of translational, mechanical energy into surface energy on a ∼10 -12 -10 -11 s time scale. At higher fluences, matter removal involves, instead, the fragmentation of an initially homogeneous fluid subjected to large strain rates upon rapid, supercritical expansion in vacuum. Under picosecond irradiation, homogeneous and, at later times, heterogeneous melting of the superheated solid are followed by nonisochoric heating of the molten metal. In this case, the subcritical liquid material is subsequently cooled onto the binodal by thermal conduction and explosive boiling does not take place; as a result, ablation is associated with a ''trivial'' fragmentation process, i.e., the relatively slow expansion and dissociation into liquid droplets of supercritical matter near thermodynamic equilibrium. This implies a liquid-vapor equilibration time of ∼10 -11 -10 -10 s and heating along the binodal under nanosecond irradiation. Solidification of the nonablated, supercooled molten material is eventually observed on a ∼10 -11 -10 -9 s time scale

  15. Laser stand for irradiation of targets by laser pulses from the Iskra-5 facility at a repetition rate of 100 MHz

    International Nuclear Information System (INIS)

    Annenkov, V I; Garanin, Sergey G; Eroshenko, V A; Zhidkov, N V; Zubkov, A V; Kalipanov, S V; Kalmykov, N A; Kovalenko, V P; Krotov, V A; Lapin, S G; Martynenko, S P; Pankratov, V I; Faizullin, V S; Khrustalev, V A; Khudikov, N M; Chebotar, V S

    2009-01-01

    A train of a few tens of high-power subnanosecond laser pulses with a repetition period of 10 ns is generated in the Iskra-5 facility. The laser pulse train has an energy of up to 300 J and contains up to 40 pulses (by the 0.15 intensity level), the single pulse duration in the train being ∼0.5 ns. The results of experiments on conversion of a train of laser pulses to a train of X-ray pulses are presented. Upon irradiation of a tungsten target, a train of X-ray pulses is generated with the shape of an envelope in the spectral band from 0.18 to 0.28 keV similar to that of the envelope of the laser pulse train. The duration of a single X-ray pulse in the train is equal to that of a single laser pulse. (lasers)

  16. Energy Storage System for a Pulsed DEMO

    International Nuclear Information System (INIS)

    Lucas, J.; Cortes, M.; Mendez, P.; Maisonnier, D.; Hayward, J.

    2006-01-01

    Several designs have been proposed for DEMO, some of which will operate in pulsed mode. Since a fusion power plant will be required to deliver continuous output, this challenge must be solved. For the reference DEMO, energy storage is required at a level of 250 MWhe with a capability of delivering a power of 1 GWe. Although DEMO is scheduled to be built in about 30 years, the design of the energy storage system must be based on current technology, focusing on commercially available products and on their expected future trends. From a thorough review of the different technologies available, thermal energy storage, compressed air energy storage, water pumping, fuel cells, batteries, flywheels and ultracapacitors are the most promising solutions to energy storage for a pulsed DEMO. An outline of each of these technologies is described in the paper, showing its basis, features, advantages and disadvantages for this application. Following this review, the most suitable methods capable of storing the required energy are examined. Fuel cells are not suitable due to the power requirement. Compressed air energy storage has a lower efficiency than the required one. Thermal energy storage, based on molten salts, so more energy can be stored with a better efficiency, and water pumping are shown as the main solutions, based on existing technology. However, those are not the only solutions capable of solving our challenge. Hydrogen production, using water electrolysis, hydrogen storage and combustion in a combined cycle can achieve our energy and power requirements with an acceptable efficiency. All these solutions are studied in detail and described, evaluating their current cost and efficiency in order to compare them all. (author)

  17. Food irradiation by low energy electrons

    International Nuclear Information System (INIS)

    Bird, J.R.

    1985-01-01

    For some special cases, the use of low energy electrons has advantages over the use of gamma-rays or higher energy electrons for the direct irradiation of food. These advantages arise from details of the interaction processes which are responsible for the production of physical, chemical and biological effects. Factors involved include depth of penetration, dose distribution, irradiation geometry, the possible production of radioactivity and costs

  18. Effect of laser pulse energies in laser induced breakdown spectroscopy in double-pulse configuration

    International Nuclear Information System (INIS)

    Benedetti, P.A.; Cristoforetti, G.; Legnaioli, S.; Palleschi, V.; Pardini, L.; Salvetti, A.; Tognoni, E.

    2005-01-01

    In this paper, the effect of laser pulse energy on double-pulse laser induced breakdown spectroscopy signal is studied. In particular, the energy of the first pulse has been changed, while the second pulse energy is held fixed. A systematic study of the laser induced breakdown spectroscopy signal dependence on the interpulse delay is performed, and the results are compared with the ones obtained with a single laser pulse of energy corresponding to the sum of the two pulses. At the same time, the crater formed at the target surface is studied by video-confocal microscopy, and the variation in crater dimensions is correlated to the enhancement of the laser induced breakdown spectroscopy signal. The results obtained are consistent with the interpretation of the double-pulse laser induced breakdown spectroscopy signal enhancement in terms of the changes in ambient gas pressure produced by the shock wave induced by the first laser pulse

  19. Efficient modeling for pulsed activation in inertial fusion energy reactors

    International Nuclear Information System (INIS)

    Sanz, J.; Yuste, P.; Reyes, S.; Latkowski, J.F.

    2000-01-01

    First structural wall material (FSW) materials in inertial fusion energy (IFE) power reactors will be irradiated under typical repetition rates of 1-10 Hz, for an operation time as long as the total reactor lifetime. The main objective of the present work is to determine whether a continuous-pulsed (CP) approach can be an efficient method in modeling the pulsed activation process for operating conditions of FSW materials. The accuracy and practicability of this method was investigated both analytically and (for reaction/decay chains of two and three nuclides) by computational simulation. It was found that CP modeling is an accurate and practical method for calculating the neutron-activation of FSW materials. Its use is recommended instead of the equivalent steady-state method or the exact pulsed modeling. Moreover, the applicability of this method to components of an IFE power plant subject to repetition rates lower than those of the FSW is still being studied. The analytical investigation was performed for 0.05 Hz, which could be typical for the coolant. Conclusions seem to be similar to those obtained for the FSW. However, further future work is needed for a final answer

  20. Ablation spot area and impulse characteristics of polymers induced by burst irradiation of 1 μm laser pulses

    Science.gov (United States)

    Tsuruta, Hisashi; Dondelewski, Oskar; Katagiri, Yusuke; Wang, Bin; Sasoh, Akihiro

    2017-07-01

    The ablation spot area and impulse characteristics of various polymers were experimentally investigated against burst irradiation of Nd: YLF laser pulses with a pulse repetition frequency of 1 kHz, wavelength of 1047 nm, temporal pulse width of 10 ns, and single-pulse fluence of 6.1 J/cm2 to 17.1 J/cm2. The dependences of ablation area on the pulse energy from 0.72 to 7.48 mJ and the number of pulses from 10 pulses to 1000 pulses were investigated. In order to characterize their impulse performance as a function of fluence, which should not depend on ablation material, an effective ablation spot area was defined as that obtained against aluminum, 1050 A, as the reference material. An impulse that resulted from a single burst of 200 pulses was measured with a torsion-type impulse stand. Various impulse dependences on the fluence, which were not readily predicted from the optical properties of the material without ablation, were obtained. By fitting the experimentally measured impulse performance to Phipps and Sinko's model in the vapor regime, the effective absorption coefficient with laser ablation was evaluated, thereby resulting in three to six orders of magnitude larger than that without ablation. Among the polymers examined using polytetrafluoroethylene (PTFE) as the best volume absorbers, the highest momentum coupling coefficient of 66 μNs/J was obtained with an effective absorption coefficient more than six times smaller than that of the other polymers.

  1. Calculational models for the treatment of pulsed/intermittent activation within fusion energy devices

    International Nuclear Information System (INIS)

    Spangler, S.E.; Sisolak, J.E.; Henderson, D.L.

    1993-01-01

    Two calculationally efficient methods have been developed to compute the induced radioactivity due to pulsed/intermittent irradiation histories as encountered in both magnetic and inertial fusion energy devices. The numerical algorithms are based on the linear chain method (Bateman Equations) and employ series reduction and matrix algebra. The first method models the case in which the irradiated materials are present throughout a series of irradiation pulses. The second method treats the case where a fixed amount of radioactive and transmuted material is created during each pulse. Analytical solutions are given for each method for a three nuclide linear chain. Numerical results and comparisons are presented for a select number of linear chains. (orig.)

  2. Energy uses in combination processes applying irradiation

    International Nuclear Information System (INIS)

    Brynjolfsson, A.

    1998-01-01

    The costs of energy in the food system are significant and have increased as a result of the growth in population worldwide. This, in turn, demands an increased harvest per area of land, and thus intensive agriculture. The energy used in the food system is not only a drain on limited resources but also has an adverse impact on the environment. It is therefore important to devise methods that reduce energy in all undertakings. The energy used in food irradiation is relatively low compared with other methods and relative to the amount of energy used in producing food. for this reason, food irradiation is an environmentally friendly method and the costs of processing and preserving food do not depend greatly on the fluctuating costs of renewable energy sources such as oil. Irradiation in 60 Co facilities uses a very small amount of energy, about 0.032-0.0465 MJ/kg for radicidation doses of 3 kGy. Irradiation in 5 MV DC electron accelerator facilities uses about twice as much energy; 10 MV travelling wave accelerator facilities use about five times as much and 5 MV X ray facilities about 25 times as much as 60 Co facilities. In practice, X ray facilities are employed only for low dose applications such as sprout inhibition, inactivation of trichina in pork products and disinfestation of fruits, therefore the energy used in low. Frequently, irradiation can be used in combination with other low energy methods such as the sun drying of spices, condiments, vegetables and fish. The overall method of preservation is then particularly environmentally friendly and results in microbiologically safe and wholesome food. (author)

  3. Energy-dependent losses in pulsed-feedback preamplifiers

    International Nuclear Information System (INIS)

    Landis, D.A.; Madden, N.W.; Goulding, F.S.

    1978-11-01

    Energy dependent counting losses occur in most pulsed-feedback preamplifiers due to the loss of those pulses which activate the recharge system. A pulsed-feedback system that overcomes this inefficiency is described. Pulsed-light feedback as used with germanium gamma-ray spectrometers is discussed as used at high energies and high rates where those losses become significant. Experimental results are presented

  4. Effect of laser pulse parameters on the size and fluorescence of nanodiamonds formed upon pulsed-laser irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Peikang [School of Materials Science and Engineering, North University of China, Taiyuan 030051 (China); Hu, Shengliang, E-mail: hsliang@yeah.net [Key Laboratory of Instrumentation Science and Dynamic Measurement (North University of China), Ministry of Education, National Key Laboratory Science and Technology on Electronic Test and Measurement, Taiyuan 030051 (China); School of Materials Science and Engineering, North University of China, Taiyuan 030051 (China); Zhang, Taiping; Sun, Jing [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Cao, Shirui [School of Materials Science and Engineering, North University of China, Taiyuan 030051 (China)

    2010-07-15

    The size of nanodiamonds formed upon laser irradiation could be easily controlled over simply adjusting laser pulse parameters. The stable size and structure of nanodiamonds were mostly determined by laser power density and pulse width. Both large nanodiamonds with multiply twinning structure (MTS) and small nanodiamonds with single crystalline structure (SCS) emitted strong visible light after surface passivation, and their fluorescence quantum yield (QY) was 4.6% and 7.1%, respectively.

  5. Effect of laser pulse parameters on the size and fluorescence of nanodiamonds formed upon pulsed-laser irradiation

    International Nuclear Information System (INIS)

    Bai, Peikang; Hu, Shengliang; Zhang, Taiping; Sun, Jing; Cao, Shirui

    2010-01-01

    The size of nanodiamonds formed upon laser irradiation could be easily controlled over simply adjusting laser pulse parameters. The stable size and structure of nanodiamonds were mostly determined by laser power density and pulse width. Both large nanodiamonds with multiply twinning structure (MTS) and small nanodiamonds with single crystalline structure (SCS) emitted strong visible light after surface passivation, and their fluorescence quantum yield (QY) was 4.6% and 7.1%, respectively.

  6. Energy storage system for a pulsed DEMO

    International Nuclear Information System (INIS)

    Lucas, J.; Cortes, M.; Mendez, P.; Hayward, J.; Maisonnier, D.

    2007-01-01

    Several designs have been proposed for the DEMO fusion reactor. Some of them are working in a non-steady state mode. Since a power plant should be able to deliver to the grid a constant power, this challenge must be solved. Energy storage is required at a level of 250 MWh e with the capability of delivering a power of 1 GWe. A review of different technologies for energy storage is made. Thermal energy storage (TES), fuel cells and other hydrogen storage, compressed air storage, water pumping, batteries, flywheels and supercapacitors are the most promising solutions to energy storage. Each one is briefly described in the paper, showing its basis, features, advantages and disadvantages for this application. The conclusion of the review is that, based on existing technology, thermal energy storage using molten salts and a system based on hydrogen storage are the most promising candidates to meet the requirements of a pulsed DEMO. These systems are investigated in more detail together with an economic assessment of each

  7. Ablation, surface activation, and electroless metallization of insulating materials by pulsed excimer laser irradiation

    International Nuclear Information System (INIS)

    Lowndes, D.H.; Godbole, M.J.; Pedraza, A.J.

    1993-01-01

    Pulsed-laser irradiation of wide bandgap ceramic substrates, using photons with sub-bandgap energies, activates the ceramic surface for subsequent electroless copper deposition. The copper deposit is confined within the irradiated region when the substrate is subsequently immersed in an electroless copper bath. However, a high laser fluence (typically several j/cm 2 ) and repeated laser shots are needed to obtain uniform copper coverage by this direct-irradiation process. In contrast, by first applying an evaporated SiO x thin film (with x ∼1), laser ablation at quite low energy density (∼0.5 J/cm 2 ) results in re-deposition on the ceramic substrate of material that is catalytic for subsequent electroless copper deposition. Experiments indicate that the re-deposited material is on silicon, on which copper nucleates. Using an SiO x film on a laser-transparent substrate, quite fine (∼12 μm) copper lines can be formed at the boundary of the region that is laser-etched in SiO x . Using SiO x with an absorbing (polycrystalline) ceramic substrate, more-or-less uniform activation and subsequent copper deposition are obtained. In the later case, interactions with the ceramic substrate also may be important for uniform deposition

  8. Very high pulse-energy accelerators

    International Nuclear Information System (INIS)

    Ramirez, J.J.

    1989-01-01

    The dominant trend in the development of pulsed power accelerator technology over the last decade has been towards higher power and shorter pulse widths. Limitations in high voltage, high current switch performance, and in power flow through vacuum insulator housings led to the development of highly modular designs. This modular approach requires precise synchronization of the various modules and efficient methods of combining the power from these modules to drive a common load. The need to drive very low impedance loads led to effective ways to combine these modules in parallel. The Particle Beam Fusion Accelerator I (PBFA I) and Saturn are representative of these designs. Hermes III represent a new approach towards the efficient generation of higher voltages. It is designed to drive a 22-MV, 730-kA, 40-ns electron beam diode and combines conventional, modular pulsed power technology with linear induction accelerator concepts. High-power induction accelerator cavities are combined with voltage addition along a MITL to generate the desired output. This design differs from a conventional linac in that the voltages are added by the MITL flow rather than by a drifting beam that gains kinetic energy at each stage. This design is a major extrapolation of previous state-of-the-art technology represented by the injector module of the Advanced Test Accelerator and has proven to be efficient and reliable. The design and performance of Hermes III are presented together with a discussion of the application of this technology to the light ion beam inertial confinement fusion program. 18 refs., 9 figs

  9. Effects of gamma irradiations on reactive pulsed laser deposited vanadium dioxide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Madiba, I.G., E-mail: madibagiven@gmail.com [UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology, College of Graduate Studies, University of South Africa (UNISA), Muckleneuk Ridge, P O Box 392, Pretoria (South Africa); Empa, Swiss Federal Laboratories Materials Science and Technology, CH-8600 Dübendorf (Switzerland); Émond, N.; Chaker, M. [Institut National de la Recherche Scientifique (INRS),1650 Blvd. Lionel-Boulet, Varennes, Québec J3X1S2 (Canada); Thema, F.T. [UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology, College of Graduate Studies, University of South Africa (UNISA), Muckleneuk Ridge, P O Box 392, Pretoria (South Africa); iThemba LABS-National Research Foundation, 1 Old Faure Road, Somerset West 7129, PO Box 722, Somerset West, Western Cape Province (South Africa); Tadadjeu, S.I. [iThemba LABS-National Research Foundation, 1 Old Faure Road, Somerset West 7129, PO Box 722, Somerset West, Western Cape Province (South Africa); Department of Electrical, Electronics and Computer Engineering, French South African Institute of Technology/Cape Peninsula University of Technology, Bellville campus, PO Box 1906, Bellville, 7530 (South Africa); Muller, U.; Zolliker, P. [Empa, Swiss Federal Laboratories Materials Science and Technology, CH-8600 Dübendorf (Switzerland); Braun, A. [ETH Zurich, Swiss Federal Institute of Technology, CH-8057, Zurich (Switzerland); Empa, Swiss Federal Laboratories Materials Science and Technology, CH-8600 Dübendorf (Switzerland); Kotsedi, L. [iThemba LABS-National Research Foundation, 1 Old Faure Road, Somerset West 7129, PO Box 722, Somerset West, Western Cape Province (South Africa); and others

    2017-07-31

    Highlights: • Synthesis of VO{sub 2} thin films by Reactive pulsed laser deposition has been achieved. • Properties VO{sub 2} remain mainly unaffected when subjected to gamma ray doses similar to those encountered during space missions. • The long range crystal structure of VO{sub 2} remains intact upon irradiation on different doses up to 100 kGy. • XPS reveals a shift from V{sup 4+} to V{sup 5+} oxidation state upon irradiation, due to the frenkel pair formation on the surface. • Irradiated films show the characteristic SMT of VO{sub 2}, although the electrical and optical properties are slightly affected. - Abstract: Vanadium oxide films are considered suitable coatings for various applications such as thermal protective coating of small spacecrafts because of their thermochromic properties. While in outer space, such coating will be exposed to cosmic radiations which include γ-rays. To study the effect of these γ-rays on the coating properties, we have deposited vanadium dioxide (VO{sub 2}) films on silicon substrates and subjected them to extensive γ-irradiations with typical doses encountered in space missions. The prevalent crystallographic phase after irradiation remains the monoclinic VO{sub 2} phase but the films preferential orientation shifts to lower angles due to the presence of disordered regions caused by radiations. Raman spectroscopy measurements also evidences that the VO{sub 2} structure is slightly affected by gamma irradiation. Indeed, increasing the gamma rays dose locally alters the crystalline and electronic structures of the films by modifying the V–V inter-dimer distance, which in turns favours the presence of the VO{sub 2} metallic phase. From the XPS measurements of V2p and O1s core level spectra, an oxidation of vanadium from V{sup 4+} towards V{sup 5+} is revealed. The data also reveal a hydroxylation upon irradiation which is corroborated by the vanishing of a low oxidation state peak near the Fermi energy in the

  10. Measurements of absorbed energy distributions in water from pulsed electron beams

    International Nuclear Information System (INIS)

    Devanney, J.A.

    1974-01-01

    An evaluation of the use of a holographic interferometer to measure the energy deposition as a function of depth in water from pulsed electron beams, together with a brief description of the interferometer and the technique of generating a hologram are presented. The holographic interferometer is used to measure the energy deposition as a function of depth in water from various pulsed beams of monoenergetic electrons in the energy range from 1.0 to 2.5 MeV. These results are compared to those computed by using a Monte Carlo radiation transport code, ETRAN-15, for the same electron energies. After the discrepancies between the measured and computed results are evaluated, reasonable agreement is found between the measured and computed absorbed energy distributions as a function of depth in water. An evalutation of the response of the interferometer as a function of electron intensities is performed. A comparison among four energy deposition curves that result from the irradiation of water with pulsed electron beams from a Febetron accelerator, model 705, is presented. These pulsed beams were produced by the same vacuum diode with the same charging voltage. The results indicate that the energy distribution of the electrons in the pulsed beam is not always constant. A comparison of the energy deposition curves that result from the irradiation of water with electron pulses from different vacuum diodes but the same charging voltage is presented. These results indicate again that the energy distribution of the electrons in the pulsed beam may vary between vacuum diodes. These differences would not be realized by using a totally absorbing metal calorimeter and Faraday Cup

  11. Stored energy in irradiated silicon carbide

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-04-01

    This report presents a short review of the phenomenon of Wigner stored energy release from irradiated graphite and discusses it in relation to neutron irradiation of silicon carbide. A single published work in the area of stored energy release in SiC is reviewed and the results are discussed. It appears from this previous work that because the combination of the comparatively high specific heat of SiC and distribution in activation energies for recombining defects, the stored energy release of SiC should only be a problem at temperatures lower than those considered for fusion devices. The conclusion of this preliminary review is that the stored energy release in SiC will not be sufficient to cause catastrophic heating in fusion reactor components, though further study would be desirable.

  12. Pulsed power generators using an inductive energy storage system

    International Nuclear Information System (INIS)

    Akiyama, H.; Sueda, T.; Katschinski, U.; Katsuki, S.; Maeda, S.

    1996-01-01

    The pulsed power generators using an inductive energy storage system are extremely compact and lightweight in comparison with those using a capacitive energy storage system. The reliable and repetitively operated opening switch is necessary to realize the inductive pulsed power generator. Here, the pulsed power generators using the inductive energy storage system, which have been developed in Kumamoto University, are summarized. copyright 1996 American Institute of Physics

  13. Temperature response of biological materials to pulsed non-ablative CO2 laser irradiation

    NARCIS (Netherlands)

    Brugmans, M. J.; Kemper, J.; Gijsbers, G. H.; van der Meulen, F. W.; van Gemert, M. J.

    1991-01-01

    This paper presents surface temperature responses of various tissue phantoms and in vitro and in vivo biological materials in air to non-ablative pulsed CO2 laser irradiation, measured with a thermocamera. We studied cooling off behavior of the materials after a laser pulse, to come to an

  14. Improvement of the mechanical and frictional properties of steels by continuous and pulsed ion irradiation

    International Nuclear Information System (INIS)

    Romanov, I.G.

    1992-01-01

    Effect of continuous and powerful pulsed ion beams (PIB) on structural, mechanical, tribological properties and surface morphology of steels were investigated. The results obtained demonstrate the significant influence of ion irradiation type on microhardness, friction coefficient, wear resistance and surface roughness characteristics. Friction coefficient variation in irradiated steels is interpreted within the framework of an adhesion-deformation model

  15. Resonant creep enhancement in austenitic stainless steels due to pulsed irradiation at low doses

    International Nuclear Information System (INIS)

    Kishimoto, N.; Amekura, H.; Saito, T.

    1994-01-01

    Steady-state irradiation creep of austenitic stainless steels has been extensively studied as one of the most important design parameters in fusion reactors. The steady-state irradiation creep has been evaluated using in-pile and light-ion experiments. Those creep compliances of various austenitic steels range in the vicinity of ε/Gσ = 10 -6 ∼10 -5 (dpa sm-bullet MPa) -1 , depending on chemical composition etc. The mechanism of steady-state irradiation creep has been elucidated, essentially in terms of stress-induced preferential absorption of point defects into dislocations, and their climb motion. From this standpoint, low doses such as 10 -3 ∼10 -1 dpa would not give rise to any serious creep, and the irradiation creep may not be a critical issue for the low-dose fusion devices including ITER. It is, however, possible that pulsed irradiation causes different creep behaviors from the steady-state one due to dynamic unbalance of interstitials and vacancies. The authors have actually observed anomalous creep enhancement due to pulsed irradiation in austenitic stainless steels. The resonant behavior of creep indicates that pulsed irradiation may cause significant deformation in austenitic steels even at such low doses and slow pulsing rates, especially for the SA-materials. The first-wall materials in plasma operation of ∼10 2 s may suffer from unexpected transient creep, even in the near-term fusion deices, such as ITER. Though this effect might be a transient effect for a relatively short period, it should be taken into account that the pulsed irradiation makes influences on stress relaxation of the fusion components and on the irradiation fatigue. The mechanism and the relevant behaviors of pulse-induced creep will be discussed in terms of a point-defect model based on the resonant interstitial enrichment

  16. Effects of laser wavelengths and pulse energy ratio on the emission enhancement in dual pulse LIBS

    International Nuclear Information System (INIS)

    Ahmed, Rizwan; Iqbal, Javed; Baig, M Aslam

    2015-01-01

    We present new studies on the effects of laser wavelengths, pulse energy ratio and interpulse delay between two laser pulses in the collinear dual pulse configuration of laser-induced breakdown spectroscopy (LIBS) on an iron sample in air using the fundamental (1064 nm) and the second harmonics (532 nm) of Nd:YAG lasers. In the dual pulse LIBS, an optimum value of interpulse delay with an appropriate combination of laser wavelengths, and laser pulse energy ratio, yields a 30 times signal intensity enhancement in the neutral iron lines as compared with single pulse LIBS. A comparison in the spatial variations of electron temperature along the axis of the plume expansion in single and double pulse LIBS has also been studied. (letter)

  17. Study on irradiation effects of nucleus electromagnetic pulse on single chip computer system

    International Nuclear Information System (INIS)

    Hou Minsheng; Liu Shanghe; Wang Shuping

    2001-01-01

    Intense electromagnetic pulse, namely nucleus electromagnetic pulse (NEMP), lightning electromagnetic pulse (LEMP) and high power microwave (HPM), can disturb and destroy the single chip computer system. To study this issue, the authors made irradiation experiments by NEMPs generated by gigahertz transversal electromagnetic (GTEM) Cell. The experiments show that shutdown, restarting, communication errors of the single chip microcomputer system would occur when it was irradiated by the NEMPs. Based on the experiments, the cause on the effects on the single chip microcomputer system is discussed

  18. First-principles electron dynamics control simulation of diamond under femtosecond laser pulse train irradiation

    International Nuclear Information System (INIS)

    Wang Cong; Jiang Lan; Wang Feng; Li Xin; Yuan Yanping; Xiao Hai; Tsai, Hai-Lung; Lu Yongfeng

    2012-01-01

    A real-time and real-space time-dependent density functional is applied to simulate the nonlinear electron-photon interactions during shaped femtosecond laser pulse train ablation of diamond. Effects of the key pulse train parameters such as the pulse separation, spatial/temporal pulse energy distribution and pulse number per train on the electron excitation and energy absorption are discussed. The calculations show that photon-electron interactions and transient localized electron dynamics can be controlled including photon absorption, electron excitation, electron density, and free electron distribution by the ultrafast laser pulse train. (paper)

  19. Pulsed UV laser-induced modifications in optical and structural characteristics of alpha-irradiated PM-355 SSNTD.

    Science.gov (United States)

    Alghamdi, S S; Farooq, W A; Baig, M R; Algarawi, M S; Alrashidi, Talal Mohammed; Ali, Syed Mansoor; Alfaramawi, K

    2017-10-01

    Pre- and postalpha-exposed PM-355 detectors were irradiated using UV laser with different number of pulses (100, 150, 200, 300, and 400). UV laser beam energy of 20mJ per pulse with a pulse width of 9ns was incident on an area of 19.6mm 2 of the samples. XRD spectra indicated that for both reference and UV-irradiated samples, the structure is amorphous, but the crystallite size increases upon UV irradiation. The same results were obtained from SEM analysis. Optical properties of PM-355 polymeric solid-state nuclear track detectors were also investigated. Absorbance measurements for all PM-355 samples in the range of 200-400nm showed that the absorption edge had a blue shift up to a certain value, and then, it had an oscillating behavior. Photoluminescence spectra of PM-355 at 250nm revealed a decrease in the broadband peak intensity as a function of the number of UV pulses, while the wavelengths corresponding to the peaks had random shifts. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Chemical and physical analysis on hard tissues after irradiation with short pulse Nd:YAG laser

    International Nuclear Information System (INIS)

    Pereira, Andrea Antunes

    2003-01-01

    This work reports on a study that was designed to investigate chemical, physical and morphological alterations in the dental enamel surface. The influence of application of laser in enamel surface by microscopic technical, X-ray fluorescence for chemical analysis, physical property as well as hardness and thermal analysis with Nd:YAG laser is also pointed out. A prototype of Nd:YAG (Q-switched) laser developed at the Center of Lasers and Applications - Institute of Energetic and Nuclear Research, aiming applications in the Medical Sciences that typical wavelength of 1.064 nm was used. The modifications in human dental enamel chemical composition for major and trace elements are here outlined. The accuracy of procedures was performed by analysis of natural hydroxyapatite as standard reference material. The identification and quantification of the chemical elements presented in the dental tissue samples were performed trough EDS, XRF and INAA. We determined the rate Calcium/Phosphorus (Ca/P) for different techniques. We performed an analysis in different regions of the surface and for different areas allowing a description of the chemical change in the total area of the specimen and the assessment of the compositional homogeneity of the each specimen. A comparison between XRF and INAA is presented. Based on morphological analysis of the irradiated surfaces with short pulse Nd:YAG laser we determined the area surrounded by the irradiation for the parameters for this thesis, and this technique allowed us to visualize the regions of fusion and re-solidification. The energy densities ranged from 10 J/cm 2 to 40 J/cm 2 , with pulse width of 6, 10 e 200 ns, and repetition rates of 5 and 7 Hz. In this thesis, FTIR-spectroscopy is used to analyze powder of mineralized tissue as well as enamel, dentine, root and cementum for human and bovine teeth after irradiation with short-pulse Nd:YAG laser. Characteristic spectra were obtained for the proteins components and mineral

  1. Ultraviolet pulsed laser irradiation of multi-walled carbon nanotubes in nitrogen atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Pérez del Pino, Ángel, E-mail: aperez@icmab.es; Cabana, Laura; Tobias, Gerard [Instituto de Ciencia de Materiales de Barcelona, Consejo Superior de Investigaciones Científicas (ICMAB-CSIC), Campus UAB, 08193 Bellaterra (Spain); György, Enikö [Instituto de Ciencia de Materiales de Barcelona, Consejo Superior de Investigaciones Científicas (ICMAB-CSIC), Campus UAB, 08193 Bellaterra (Spain); National Institute for Lasers, Plasma and Radiation Physics, P. O. Box MG 36, 76900 Bucharest V (Romania); Ballesteros, Belén [ICN2—Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, 08193 Bellaterra, Barcelona (Spain)

    2014-03-07

    Laser irradiation of randomly oriented multi-walled carbon nanotube (MWCNT) networks has been carried out using a pulsed Nd:YAG UV laser in nitrogen gas environment. The evolution of the MWCNT morphology and structure as a function of laser fluence and number of accumulated laser pulses has been studied using electron microscopies and Raman spectroscopy. The observed changes are discussed and correlated with thermal simulations. The obtained results indicate that laser irradiation induces very fast, high temperature thermal cycles in MWCNTs which produce the formation of different nanocarbon forms, such as nanodiamonds. Premelting processes have been observed in localized sites by irradiation at low number of laser pulses and low fluence values. The accumulation of laser pulses and the increase in the fluence cause the full melting and amorphization of MWCNTs. The observed structural changes differ from that of conventional high temperature annealing treatments of MWCNTs.

  2. High efficiency, monolithic fiber chirped pulse amplification system for high energy femtosecond pulse generation.

    Science.gov (United States)

    Peng, Xiang; Kim, Kyungbum; Mielke, Michael; Jennings, Stephen; Masor, Gordon; Stohl, Dave; Chavez-Pirson, Arturo; Nguyen, Dan T; Rhonehouse, Dan; Zong, Jie; Churin, Dmitriy; Peyghambarian, N

    2013-10-21

    A novel monolithic fiber-optic chirped pulse amplification (CPA) system for high energy, femtosecond pulse generation is proposed and experimentally demonstrated. By employing a high gain amplifier comprising merely 20 cm of high efficiency media (HEM) gain fiber, an optimal balance of output pulse energy, optical efficiency, and B-integral is achieved. The HEM amplifier is fabricated from erbium-doped phosphate glass fiber and yields gain of 1.443 dB/cm with slope efficiency >45%. We experimentally demonstrate near diffraction-limited beam quality and near transform-limited femtosecond pulse quality at 1.55 µm wavelength. With pulse energy >100 µJ and pulse duration of 636 fs (FWHM), the peak power is estimated to be ~160 MW. NAVAIR Public Release Distribution Statement A-"Approved for Public release; distribution is unlimited".

  3. Relaxation and excitation electronic processes in dielectrics irradiated by ultrafast IR and VUV pulses

    International Nuclear Information System (INIS)

    Gaudin, J.

    2005-11-01

    We studied excitation and relaxation of electrons involved during interaction of visible and VUV femtosecond pulses with dielectrics. The generated population of hot electrons, having energy of few eV to few tens of eV above the bottom of the conduction band, is responsible of phenomena ranging to defect creation to optical breakdown. Owing to two techniques: photoemission and transient photoconductivity we improve the understanding of the The first photoemission experiments deal with dielectrics irradiated by 30 fs IR pulses. The photoemission spectra measured show a large population of electrons which energy rise up to 40 eV. We interpret this result in terms of a new absorption process: direct multi-photons inter-branch transitions. The 2. type of photoemission experiments are time resolved 'pump/probe' investigation. We study the relaxation of electrons excited by a VUV pulses. We used the high order harmonics (HOH) as light sources. We found surprisingly long decay time in the range of ps timescale. Last type of experiments is photoconductivity studies of diamond samples. Using HOH as light source we measure the displacement current induced by excited electrons in the conduction band. Those electrons relax mainly by impact ionisation creating secondary electrons. Hence by probing the number of electrons we were able to measure the efficiency of these relaxation processes. We observe a diminution of this efficiency when the energy of exciting photons is above 20 eV. Owing to Monte-Carlo simulation we interpret this result in terms of band structure effect. (author)

  4. Increase in the energy absorption of pulsed plasma by the formation of tungsten nanostructure

    Science.gov (United States)

    Sato, D.; Ohno, N.; Domon, F.; Kajita, S.; Kikuchi, Y.; Sakuma, I.

    2017-06-01

    The synergistic effects of steady-state and pulsed plasma irradiation to material have been investigated in the device NAGDIS-PG (NAGoya DIvertor Simulator with Plasma Gun). The duration of the pulsed plasma was ~0.25 ms. To investigate the pulsed plasma heat load on the materials, we developed a temperature measurement system using radiation from the sample in a high time resolution. The heat deposited in response to the transient plasma on a tungsten surface was revealed by using this system. When the nanostructures were formed by helium plasma irradiation, the temperature increase on the bulk sample was enhanced. The result suggested that the amount of absorbed energy on the surface was increased by the formation of nanostructures. The possible mechanisms causing the phenomena are discussed with the calculation of a sample temperature in response to the transient heat load.

  5. Identification of gamma irradiated pulse seed (Lens sp.) based on germination test

    International Nuclear Information System (INIS)

    Chaudhuri, Sadhan K.

    2001-01-01

    The germination test of pulse seed provided a reliable method for the identification of lentil seeds that had been subjected to irradiation. Root and shoot lengths were found more sensitive to the gamma irradiation than the germination percentages. The critical dose that prevented the root elongation varied from 0.1 kGy to 0.5 kGy. Germination percentage was reduced drastically above 0.2 kGy. Above 1.0 kGy dose, the lentil seeds did not germinate. The sensitivity of lentil seeds to gamma irradiation was inversely proportional to moisture content of the seeds. In addition, storage period up to 12 months had little effect on irradiation the induced reduction of root and shoot lengths. Thus, this test can determine the difference between irradiated and non-irradiated lentil seeds even 12 months after gamma irradiation. (author)

  6. Neutron-irradiation facilities at the Intense Pulsed Neutron Source-I for fusion magnet materials studies

    International Nuclear Information System (INIS)

    Brown, B.S.; Blewitt, T.H.

    1982-01-01

    The decommissioning of reactor-based neutron sources in the USA has led to the development of a new generation of neutron sources that employ high-energy accelerators. Among the accelerator-based neutron sources presently in operation, the highest-flux source is the Intense Pulsed Neutron Source (IPNS), a user facility at Argonne National Laboratory. Neutrons in this source are produced by the interaction of 400 to 500 MeV protons with either of two 238 U target systems. In the Radiation Effects Facility (REF), the 238 U target is surrounded by Pb for neutron generatjion and reflection. The REF has three separate irradiation thimbles. Two thimbles provide irradiation temperatures between that of liquid He and several hundred degrees centigrade. The third thimble operates at ambient temperature. The large irradiation volume, the neutron spectrum and flux, the ability to transfer samples without warm up, and the dedication of the facilities during the irradiation make this ideally suited for radiation damage studies on components for superconducting fusion magnets. Possible experiments for fusion magnet materials are discussed on cyclic irradiation and annealing of stabilizers in a high magnetic field, mechanical tests on organic insulation irradiated at 4 K, and superconductors measured in high fields after irradiation

  7. Reaction of congo red in water after irradiation by pulsed intense relativistic electron beam

    International Nuclear Information System (INIS)

    Kikuchi, Takashi; Kondo, Hironobu; Sasaki, Toru; Harada, Nob.; Moriwaki, Hiroshi; Nakanishi, Hiromitsu; Imada, Go

    2011-01-01

    The reaction of congo red, a well-known toxic azo dye, occurred after irradiation by a pulsed intense relativistic electron beam (PIREB). An aquation of congo red was irradiated by PIREB (2 MeV, 0.36 kA, 140 ns). After PIREB irradiation, the solution was measured by electrospray ionization-mass spectrometry and liquid chromatography/mass spectrometry. It was found that congo red underwent a reaction (77% conversion after five shots of PIREB irradiation) and the hydroxylated compounds of the dye were observed as reaction products. (author)

  8. Acute effects of pulsed-laser irradiation on the arterial wall

    Science.gov (United States)

    Nakamura, Fumitaka; Kvasnicka, Jan; Lu, Hanjiang; Geschwind, Herbert J.; Levame, Micheline; Bousbaa, Hassan; Lange, Francoise

    1992-08-01

    Pulsed laser coronary angioplasty with an excimer or a holmium-yttrium-aluminum-garnet (Ho:YAG) laser may become an alternative treatment for patients with coronary artery disease. However, little is known about its acute consequences on the normal arterial wall. This study was designed to examine the acute histologic consequences of these two pulsed lasers on the arterial wall of normal iliac arteries in rabbits. Irradiation with each laser was performed in 15 normal iliac sites on eight male New Zealand white rabbits. The excimer laser was operated at 308 nm, 25 Hz, 50 mJ/mm2/pulse, and 135 nsec/pulse and the Ho:YAG laser was operated at 2.1 micrometers , 3/5 Hz, 400 mJ/pulse, and 250 microsecond(s) ec/pulse. The excimer and Ho:YAG laser were coupled into a multifiber wire-guided catheter of 1.4 and 1.5 mm diameter, respectively. The sites irradiated with excimer or Ho:YAG laser had the same kinds of histologic features, consisting of exfoliation of the endothelium, disorganization of internal elastic lamina, localized necrosis of vascular smooth muscle cells, and fissures in the medial layer. However, the sites irradiated with excimer laser had lower grading scores than those irradiated with Ho:YAG laser (p vascular injury.

  9. Use of TRIGA-pulsed irradiations for high-temperature Doppler measurements

    Energy Technology Data Exchange (ETDEWEB)

    Foell, W K; Cashwell, R J; Bhattacharyya, S K [Argonne National Laboratory, Argonne, IL (United States); Russell, G J [Los Alamos Scientific Laboratory, University of California, Los Alamos, NM (United States)

    1974-07-01

    Conventional activation and reactivity measurements of the nuclear Doppler Effect have been limited to temperatures of about 2000{sup o}K because of problems with furnace equipment. There is a need for Doppler data at higher temperatures for design of reactors and analysis of reactor accidents. To fill this need, a novel technique using pulsed-mode operation of a TRIGA reactor has been developed at the University of Wisconsin. This new method, the Pulsed Activation Doppler (PAD) technique, has been used successfully for high temperature Doppler measurements of UO{sub 2} fuel pellets. In the PAD technique, UO{sub 2} test pellets were doped with varying amounts of U-235, with fissile enrichments varying from 0.22% to 12% by weight. The pellets were encapsulated in individual irradiation cells and electrically preheated to predetermined temperatures. Pyrofoam-graphite heaters were used to give preheat temperatures of up to 1720 deg. K. The cells were then positioned in the University of Wisconsin TRIGA reactor core and pulse-irradiated. During the rapid irradiation, adiabatic fission energy deposition occurred in the pellets and very high temperatures (over 3115 deg, K) were attained. Corresponding resonance neutron captures occurred at the elevated temperatures. The Doppler Ratio was deduced from the gamma activities of the Np-239 in the heated and unheated reference pellets. UO{sub 2} pellets of two nominal diameters, 210 mils (a surface-to-mass ratio, s/m = 1.1 cm{sup 2} /gm) and 360 mils (s/m = 0.63 cm{sup 2}/gm), were used for the experiments. For the 210 mil diameter pellets there was very good agreement between experimental results and Doppler ratios predicted both from extrapolations of the Hellstrand low-temperature resonance integral correlations and from GAROL calculations. Significantly, the agreement was good even for those pellets which experienced extensive melting. For the 360 mil diameter pellets the theoretical predictions were 10-15% lower than

  10. Energy coupling to the plasma in repetitive nanosecond pulse discharges

    International Nuclear Information System (INIS)

    Adamovich, Igor V.; Nishihara, Munetake; Choi, Inchul; Uddi, Mruthunjaya; Lempert, Walter R.

    2009-01-01

    A new analytic quasi-one-dimensional model of energy coupling to nanosecond pulse discharge plasmas in plane-to-plane geometry has been developed. The use of a one-dimensional approach is based on images of repetitively pulsed nanosecond discharge plasmas in dry air demonstrating that the plasma remains diffuse and uniform on a nanosecond time scale over a wide range of pressures. The model provides analytic expressions for the time-dependent electric field and electron density in the plasma, electric field in the sheath, sheath boundary location, and coupled pulse energy. The analytic model predictions are in very good agreement with numerical calculations. The model demonstrates that (i) the energy coupled to the plasma during an individual nanosecond discharge pulse is controlled primarily by the capacitance of the dielectric layers and by the breakdown voltage and (ii) the pulse energy coupled to the plasma during a burst of nanosecond pulses decreases as a function of the pulse number in the burst. This occurs primarily because of plasma temperature rise and resultant reduction in breakdown voltage, such that the coupled pulse energy varies approximately proportionally to the number density. Analytic expression for coupled pulse energy scaling has been incorporated into the air plasma chemistry model, validated previously by comparing with atomic oxygen number density measurements in nanosecond pulse discharges. The results of kinetic modeling using the modified air plasma chemistry model are compared with time-resolved temperature measurements in a repetitively pulsed nanosecond discharge in air, by emission spectroscopy, and purely rotational coherent anti-Stokes Raman spectroscopy showing good agreement.

  11. Stored energy recovery of irradiated copper

    International Nuclear Information System (INIS)

    Richard, R.T.; Chaplin, R.L.; Coltman, R.R. Jr.; Kerchner, H.R.; Klabunde, C.E.

    1990-01-01

    The stored energy released in Stage I recovery of reactor neutron irradiated copper was measured by differential thermal analysis calorimetry for three fluences up to a maximum of 3.5 x 10 18 n/cm 2 (E>0.1 MeV) after irradiation at temperatures of less than 10 K. The dependence of the stored energy upon fluence, and a tendency toward saturation, were observed. Theoretical reaction rate processes were compared directly with the experimental rates of stored energy release, and the parameters associated with the theory were compared with results from previous resistivity measurements. Good agreement was found for several parameters, but major differences with previous D + E substage results lead to the conclusion that the point defect model may not describe materials experiencing severe neutron damage. Computer studies of warmup rates were made for first and second order and for correlated recovery processes as a function of defect concentration and of external power input. First and second order processes show definite distortion in their recovery rate curves for high defect concentrations; the correlated recovery process shows a much less pronounced effect. This investigation of stored energy used several new approaches. The use of induced radioactivity within the sample as the heating source, and the use of computer generated theoretical stored energy release curves to analyze the data were unique. (author)

  12. Study of intense pulse irradiation effects on silicon targets considered as ground matter for optical detectors

    International Nuclear Information System (INIS)

    Muller, O.

    1994-12-01

    This study aim was centered on morphological and structural alterations induced by laser irradiation on silicon targets considered as ground matter for optical detectors. First we recalled the main high light intensity effects on the condensed matter. Then we presented the experimental aspects. The experimental studies were achieved on two sample types: SiO 2 /Si and Si. Two topics were studied: the defect chronology according to wavelength and pulse length, and the crystalline quality as well as the structure defects of irradiated zones by Raman spectroscopy. Finally, irradiation of Si targets by intense pulsed beams may lead to material fusion. This phenomenon is particularly easy when the material is absorbent, when the pulse is short and when the material is superficially oxidized. (MML). 204 refs., 93 figs., 21 tabs., 1 appendix

  13. Pulsed energy conversion with a dc superconducting magnet

    International Nuclear Information System (INIS)

    Cowan, M.; Cnare, E.C.; Leisher, W.B.; Tucker, W.K.; Wessenberg, D.L.

    1976-01-01

    A generator system for pulsed power is described which employs a dc superconducting magnet in a magnetic flux compression scheme. Experience with a small-scale generator together with projections of numerical models indicate potential applications to fusion research and commercial power generation. When the system is large enough pulse energy can exceed that stored in the magnet and pulse rise time can range from several microseconds to tens of milliseconds. (author)

  14. Study of dielectric materials irradiated with electron beam by using the Pulsed Electro-Acoustic (PEA) method

    International Nuclear Information System (INIS)

    Nguyen, Xuan Truong

    2014-01-01

    Dielectric materials are frequently used as electrical insulators in spatial applications. Due to their dielectric nature, these dielectrics are likely to accumulate electric charges during their service. Under certain critical conditions, these internal or surface space charges can lead to an electrostatic surface discharge. To understand these phenomena, an experimental device has been developed in the laboratory. This device allows us to simulate the electronic irradiation conditions encountered in space. The aim of our study is to characterize the electrical behavior of insulating materials irradiated by electron beam, to investigate charge storage and transport phenomena and anticipate electrostatic discharges. In this work, the device based on the Pulsed Electro-Acoustic (PEA) technique has been chosen. It has been implanted in the irradiation chamber. It allows us to obtain the spatial distribution of charges injected between two periods of irradiation and during relaxation. However the PEA method offers a limited resolution and does not allow the detection of injected charges when they are too close to the surface. First, we performed a parameters signal processing analysis that we will call the spreading factor and the resolution factor. The preliminary study post-irradiation in air of experimental measurements showed that the resolution factor choice is important for the analysis and interpretation of the signal when the space charge is localized near the surface. Then, a comparison to the spreading parameter used in some deconvolution technique was established. In the second time, space charge distribution measurements in vacuum have been carried out on Poly Tetra Fluoro Ethylene (PTFE) films irradiated by an electron beam in the range [10-100] keV. Results from irradiation periods with increasing energies [10 keV → 100 keV] of the electron beam have been compared with results from irradiation periods with decreasing energies [100 keV → 10 keV]. In

  15. Experimental study of mechanical response of artificial tissue models irradiated with Nd:YAG nanosecond laser pulses

    Science.gov (United States)

    Pérez-Gutiérrez, Francisco G.; Camacho-López, Santiago; Aguilar, Guillermo

    2011-07-01

    Nanosecond long laser pulses are used in medical applications where precise tissue ablation with minimal thermal and mechanical collateral damage is required. When a laser pulse is incident on a material, optical energy will be absorbed by a combination of linear and nonlinear absorption according to both: laser light irradiance and material properties. In the case of water or gels, the first results in heat generation and thermoelastic expansion; while the second results in an expanding plasma formation that launches a shock wave and a cavitation/boiling bubble. Plasma formation due to nonlinear absorption of nanosecond laser pulses is originated by a combination of multiphoton ionization and thermionic emission of free electrons, which is enhanced when the material has high linear absorption coefficient. In this work, we present three experimental approaches to study pressure transients originated when 6 ns laser pulses are incident on agar gels and water with varying linear absorption coefficient, using laser radiant exposures above and below threshold for bubble formation: (a) PVDF sensors, (b) Time-resolved shadowgraphy and (c) Time-resolved interferometry. The underlying hypothesis is that pressure transients are composed of the superposition of both: shock wave originated by hot expanding plasma resulting from nonlinear absorption of optical energy and, thermoelastic expansion originated by heat generation due to linear absorption of optical energy. The objective of this study is to carry out a comprehensive experimental analysis of the mechanical effects that result when tissue models are irradiated with nanosecond laser pulses to elucidate the relative contribution of linear and nonlinear absorption to bubble formation. Furthermore, we investigate cavitation bubble formation with temperature increments as low as 3 °C.

  16. Laser pulse heating of steel mixing with WC particles in a irradiated region

    Science.gov (United States)

    Shuja, S. Z.; Yilbas, B. S.; Ali, H.; Karatas, C.

    2016-12-01

    Laser pulse heating of steel mixing with tungsten carbide (WC) particles is carried out. Temperature field in the irradiated region is simulated in line with the experimental conditions. In the analysis, a laser pulse parameter is introduced, which defines the laser pulse intensity distribution at the irradiated surface. The influence of the laser parameter on the melt pool size and the maximum temperature increase in the irradiated region is examined. Surface temperature predictions are compared with the experimental data. In addition, the distribution of WC particles and their re-locations in the treated layer, due to combination of the natural convection and Marangoni currents, are predicted. The findings are compared to the experimental data. It is found that surface temperature predictions agree well with the experimental data. The dislocated WC particles form a streamlining in the near region of the melt pool wall, which agree with the experimental findings. The Gaussian distribution of the laser pulse intensity results in the maximum peak temperature and the maximum flow velocity inside the melt pool. In this case, the melt pool depth becomes the largest as compared to those corresponding to other laser pulse intensity distributions at the irradiated surface.

  17. The dynamics of Al/Pt reactive multilayer ignition via pulsed-laser irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, Ryan D.; Reeves, Robert V.; Yarrington, Cole D.; Adams, David P. [Sandia National Laboratories, Albuquerque, New Mexico 87123 (United States)

    2015-12-07

    Reactive multilayers consisting of alternating layers of Al and Pt were irradiated by single laser pulses ranging from 100 μs to 100 ms in duration, resulting in the initiation of rapid, self-propagating reactions. The threshold intensities for ignition vary with the focused laser beam diameter, bilayer thickness, and pulse length and are affected by solid state reactions and conduction of heat away from the irradiated regions. High-speed photography was used to observe ignition dynamics during irradiation and elucidate the effects of heat transfer into a multilayer foil. For an increasing laser pulse length, the ignition process transitioned from a more uniform to a less uniform temperature profile within the laser-heated zone. A more uniform temperature profile is attributed to rapid heating rates and heat localization for shorter laser pulses, and a less uniform temperature profile is due to slower heating of reactants and conduction during irradiation by longer laser pulses. Finite element simulations of laser heating using measured threshold intensities indicate that micron-scale ignition of Al/Pt occurs at low temperatures, below the melting point of both reactants.

  18. Histological observation on dental hard tissue irradiated by ultrashort-pulsed laser

    Science.gov (United States)

    Uchizono, Takeyuki; Awazu, Kunio; Igarashi, Akihiro; Kato, Junji; Hirai, Yoshito

    2006-04-01

    In the field of dentistry, effectiveness of USPL irradiation is researched because USPL has less thermal side effect to dental hard tissue. In this paper, we observed morphological change and optical change of dental hard tissue irradiated by USPL for discussing the safety and effectiveness of USPL irradiation to dental hard tissues. Irradiated samples were crown enamel and root dentin of bovine teeth. Lasers were Ti:sapphire laser, which had pulse duration (P d)of 130 fsec and pulse repetition rate (f) of 1kHz and wavelength (l) of 800nm, free electron laser (FEL), which had P d of 15 μsec and f of 10Hz and wavelength of 9.6μm, and Er:YAG laser, which had P d of 250 μsec and f of 10Hz and wavelength of 2.94μm. After laser irradiation, the sample surfaces and cross sections were examined with SEM and EDX. The optical change of samples was observed using FTIR. In SEM, the samples irradiated by USPL had sharp and accurate ablation with no crack and no carbonization. But, in FEL and Er:YAG laser, the samples has rough ablation with crack and carbonization. It was cleared that the P/Ca ratio of samples irradiated by USPL had same value as non-irradiated samples. There was no change in the IR absorption spectrum between samples irradiated by USPL and non-irradiated sample. But, they of samples irradiated by FEL and Er:YAG laser, however, had difference value as non-irradiated samples. These results showed that USPL might be effective to ablate dental hard tissue without thermal damage.

  19. 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)

  20. Effect of gamma-irradiation on cereal DNA investigated by pulsed-field gel electrophoresis

    International Nuclear Information System (INIS)

    Kawamura, Yoko; Miura, Aya; Imura, Hiromi; Yamada, Takashi; Saito, Yukio

    1996-01-01

    The effects of gamma-irradiation on the DNA of corn, soybean and wheat were investigated using a pulsed-field gel electrophoresis technique. In order to avoid strand breaks during the DNA extracting steps, protoplasts prepared from seeds were embedded in agarose plugs and the DNA was purified by the digesting membranes and proteins. Pulsed-field gel electrophoresis can separate large DNA strands of about a few Mb in length. The DNA from unirradiated corn, soybean and wheat had mainly 3 fragments, about 6Mb(Fr.1), 5Mb(Fr.2), a few hundred kb(Fr.3) and so on. After gamma-irradiation, Fr.1 and Fr.2 had decreased depend on irradiation dose. The Fr.4(about 200 kb) of corn and Fr.3 of soybean DNA increased while Fr.3 of wheat did not increase under 10 kGy irradiation, however, the Fr.3 of all samples and the Fr.4 of corn decreased by over 10 kGy irradiation. It can be assumed that the large DNA strands were broken into smaller strands which increased at low irradiation doses, whereas both large and small DNA strands were broken down at higher irradiation doses. The Fr.6(2.5Mb) and Fr.7(1.5Mb) appeared in irradiated wheat DNA. (author)

  1. Simulation of continious radiation effect on semiconductors by the pulse irradiation

    International Nuclear Information System (INIS)

    Radyuk, I.A.; Fejgin, O.O.; Shein, O.V.

    1986-01-01

    The problem of the laboratory radiation modelling of semiconductor devices and integrated circuits has been under consideration. The condition of adequacy of influencing the pulsed and continuous irradiation semiconductor devices and integrated circuits have been established. The methods of comparing and calculating the influences have been discussed. A number of expressions describing the connection between the parameters of impulced and continuous irradiation have been considered

  2. Pulsed energy storage antennas for ionospheric modification

    Directory of Open Access Journals (Sweden)

    R. F. Wuerker

    2005-01-01

    Full Text Available Interesting, "new", very high peak-power pulsed radio frequency (RF antennas have been assembled at the HIPAS Observatory (Alaska, USA and also at the University of California at Los Angeles (UCLA, USA; namely, a pair of quarter wavelength (λ/4 long cylindrical conductors separated by a high voltage spark gap. Such a combination can radiate multi-megawatt RF pulses whenever the spark gap fires. The antenna at HIPAS is 53m long (λ/2 with a central pressurized SF6 spark gap. It is mounted 5 meters (λ/21 above a ground plane. It radiates at 2.85MHz. The two antenna halves are charged to ± high voltages by a Tesla coil. Spark gap voltages of 0.4 MV (at the instant of spark gap closure give peak RF currents of ~1200A which correspond to ~14 MW peak total radiated power, or ~56 MW of Effective Radiated Power (ERP. The RF pulse train is initially square, decaying exponentially in time with Qs of ~50. Two similar but smaller 80-MHz antennas were assembled at UCLA to demonstrate their synchronization with a pulsed laser which fired the spark gaps in the two antennas simultanoeously. These experiments show that one can anticipate a pulsed array of laser synchronized antennas having a coherent Effective Radiated Power (ERP>10GW. One can even reconsider a pulse array radiating at 1.43MHz which corresponds to the electron gyrofrequency in the Earth's magnetic field at ~200km altitude. These "new" pulsed high power antennas are hauntingly similar to the ones used originally by Hertz (1857-1894 during his (1886-1889 seminal verifications of Maxwell's (1864 theory of electrodynamics.

  3. Pulsed energy storage antennas for ionospheric modification

    Directory of Open Access Journals (Sweden)

    R. F. Wuerker

    2005-01-01

    Full Text Available Interesting, "new", very high peak-power pulsed radio frequency (RF antennas have been assembled at the HIPAS Observatory (Alaska, USA and also at the University of California at Los Angeles (UCLA, USA; namely, a pair of quarter wavelength (λ/4 long cylindrical conductors separated by a high voltage spark gap. Such a combination can radiate multi-megawatt RF pulses whenever the spark gap fires. The antenna at HIPAS is 53m long (λ/2 with a central pressurized SF6 spark gap. It is mounted 5 meters (λ/21 above a ground plane. It radiates at 2.85MHz. The two antenna halves are charged to ± high voltages by a Tesla coil. Spark gap voltages of 0.4 MV (at the instant of spark gap closure give peak RF currents of ~1200A which correspond to ~14 MW peak total radiated power, or ~56 MW of Effective Radiated Power (ERP. The RF pulse train is initially square, decaying exponentially in time with Qs of ~50. Two similar but smaller 80-MHz antennas were assembled at UCLA to demonstrate their synchronization with a pulsed laser which fired the spark gaps in the two antennas simultanoeously. These experiments show that one can anticipate a pulsed array of laser synchronized antennas having a coherent Effective Radiated Power (ERP>10GW. One can even reconsider a pulse array radiating at 1.43MHz which corresponds to the electron gyrofrequency in the Earth's magnetic field at ~200km altitude. These "new" pulsed high power antennas are hauntingly similar to the ones used originally by Hertz (1857-1894 during his (1886-1889 seminal verifications of Maxwell's (1864 theory of electrodynamics.

  4. Retinal response of Macaca mulatta to picosecond laser pulses of varying energy and spot size.

    Science.gov (United States)

    Roach, William P; Cain, Clarence P; Narayan, Drew G; Noojin, Gary D; Boppart, Stephen A; Birngruber, Reginald; Fujimoto, James G; Toth, Cynthia A

    2004-01-01

    We investigate the relationship between the laser beam at the retina (spot size) and the extent of retinal injury from single ultrashort laser pulses. From previous studies it is believed that the retinal effect of single 3-ps laser pulses should vary in extent and location, depending on the occurrence of laser-induced breakdown (LIB) at the site of laser delivery. Single 3-ps pulses of 580-nm laser energy are delivered over a range of spot sizes to the retina of Macaca mulatta. The retinal response is captured sequentially with optical coherence tomography (OCT). The in vivo OCT images and the extent of pathology on final microscopic sections of the laser site are compared. With delivery of a laser pulse with peak irradiance greater than that required for LIB, OCT and light micrographs demonstrate inner retinal injury with many intraretinal and/or vitreous hemorrhages. In contrast, broad outer retinal injury with minimal to no choriocapillaris effect is seen after delivery of laser pulses to a larger retinal area (60 to 300 microm diam) when peak irradiance is less than that required for LIB. The broader lesions extend into the inner retina when higher energy delivery produces intraretinal injury. Microscopic examination of stained fixed tissues provide better resolution of retinal morphology than OCT. OCT provides less resolution but could be guided over an in vivo, visible retinal lesion for repeated sampling over time during the evolution of the lesion formation. For 3-ps visible wavelength laser pulses, varying the spot size and laser energy directly affects the extent of retinal injury. This again is believed to be partly due to the onset of LIB, as seen in previous studies. Spot-size dependence should be considered when comparing studies of retinal effects or when pursuing a specific retinal effect from ultrashort laser pulses. Copyright 2004 Society of Photo-Optical Instrumentation Engineers.

  5. Changing of micromorphology of silicon-on-sapphire epitaxial layer surface at irradiation by subthreshold energy X-radiation

    CERN Document Server

    Kiselev, A N; Skupov, V D; Filatov, D O

    2001-01-01

    The morphology of silicon-on-sapphire epitaxial layer surface after pulse irradiation by the X-rays with the energy of <= 140 keV is studied. The study on the irradiated material surface is carried out by the methods of the atomic force microscopy and ellipsometry. The average roughness value after irradiation constitutes 7 nm. The change in the films surface microrelief occurs due to reconstruction of their dislocation structure under the action of elastic waves, originating in the X radiation

  6. Channels of energy redistribution in short-pulse laser interactions with metal targets

    International Nuclear Information System (INIS)

    Zhigilei, Leonid V.; Ivanov, Dmitriy S.

    2005-01-01

    The kinetics and channels of laser energy redistribution in a target irradiated by a short, 1 ps, laser pulse is investigated in computer simulations performed with a model that combines molecular dynamics (MD) simulations with a continuum description of the laser excitation and relaxation of the conduction band electrons, based on the two-temperature model (TTM). The energy transferred from the excited electrons to the lattice splits into several parts, namely the energy of the thermal motion of the atoms, the energy of collective atomic motions associated with the relaxation of laser-induced stresses, the energy carried away from the surface region of the target by a stress wave, the energy of quasi-static anisotropic stresses, and, at laser fluences above the melting threshold, the energy transferred to the latent heat of melting and then released upon recrystallization. The presence of the non-thermal channels of energy redistribution (stress wave and quasi-static stresses), not accounted for in the conventional TTM model, can have important implications for interpretation of experimental results on the kinetics of thermal and mechanical relaxation of a target irradiated by a short laser pulse as well as on the characteristics of laser-induced phase transformations. The fraction of the non-thermal energy in the total laser energy partitioning increases with increasing laser fluence

  7. Surface modification of ceramic materials induced by irradiation of high power pulsed ICP

    International Nuclear Information System (INIS)

    Ishigaki, Takamasa; Okada, Nobuhiro; Ohashi, Naoki; Haneda, Hajime

    2003-01-01

    Newly developed pulse-modulated high-power inductively coupled plasma [ICP] is expected to offer the unique physico-chemical condition, such as the increased concentration of chemically reactive species, as well as the appropriate heat flux for materials processing. Two kinds of oxide materials, titanium and zinc oxide, were placed at the downstream of Ar-H 2 ICP and irradiated in the plasma of continuous [CN] and pulse-modulated [PM] modes. The CN-ICP irradiation at the position close to the plasma tail gave rise to the thermal reduction of oxides. In the PM-ICP irradiation, the degree of thermal reduction depended on the lower power level during pulse-off time, as well as the total electric power. Irradiation in PM-ICP led to the increased formation of oxygen vacancies in titanium dioxide. In the case of zinc oxide, the UV emission efficiency was improved by PM-ICP irradiation, while the green emission became predominant by CN-ICP irradiation at the appropriate position. Induced effects in the two oxides by PM-ICP would be related to the high concentration of hydrogen radicals in the plasma. (author)

  8. Non-destructive diagnostics of irradiated materials using neutron scattering from pulsed neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    Korenev, Sergey E-mail: sergey_korenev@steris.com; Sikolenko, Vadim

    2004-10-01

    The advantage of neutron-scattering studies as compared to the standard X-ray technique is the high penetration of neutrons that allow us to study volume effects. The high resolution of instrumentation on the basis neutron scattering allows measurement of the parameters of lattice structure with high precision. We suggest the use of neutron scattering from pulsed neutron sources for analysis of materials irradiated with pulsed high current electron and ion beams. The results of preliminary tests using this method for Ni foils that have been studied by neutron diffraction at the IBR-2 (Pulsed Fast Reactor at Joint Institute for Nuclear Research) are presented.

  9. Non-destructive diagnostics of irradiated materials using neutron scattering from pulsed neutron sources

    Science.gov (United States)

    Korenev, Sergey; Sikolenko, Vadim

    2004-09-01

    The advantage of neutron-scattering studies as compared to the standard X-ray technique is the high penetration of neutrons that allow us to study volume effects. The high resolution of instrumentation on the basis neutron scattering allows measurement of the parameters of lattice structure with high precision. We suggest the use of neutron scattering from pulsed neutron sources for analysis of materials irradiated with pulsed high current electron and ion beams. The results of preliminary tests using this method for Ni foils that have been studied by neutron diffraction at the IBR-2 (Pulsed Fast Reactor at Joint Institute for Nuclear Research) are presented.

  10. Evaluation of temperature history of a spherical nanosystem irradiated with various short-pulse laser sources

    Science.gov (United States)

    Lahiri, Arnab; Mondal, Pranab K.

    2018-04-01

    Spatiotemporal thermal response and characteristics of net entropy production rate of a gold nanosphere (radius: 50-200 nm), subjected to a short-pulse, femtosecond laser is reported. In order to correctly illustrate the temperature history of laser-metal interaction(s) at picoseconds transient with a comprehensive single temperature definition in macroscale and to further understand how the thermophysical response of the single-phase lag (SPL) and dual-phase lag (DPL) frameworks (with various lag-ratios') differs, governing energy equations derived from these benchmark non-Fourier frameworks are numerically solved and thermodynamic assessment under both the classical irreversible thermodynamics (CIT) as well as extended irreversible thermodynamics (EIT) frameworks is subsequently carried out. Under the frameworks of SPL and DPL with small lag ratio, thermophysical anomalies such as temperature overshooting characterized by adverse temperature gradient is observed to violate the local thermodynamic equilibrium (LTE) hypothesis. The EIT framework, however, justifies the compatibility of overshooting of temperature with the second law of thermodynamics under a nonequilibrium paradigm. The DPL framework with higher lag ratio was however observed to remain free from temperature overshooting and finds suitable consistency with LTE hypothesis. In order to solve the dimensional non-Fourier governing energy equation with volumetric laser-irradiation source term(s), the lattice Boltzmann method (LBM) is extended and a three-time level, fully implicit, second order accurate finite difference method (FDM) is illustrated. For all situations under observation, the LBM scheme is featured to be computationally superior to remaining FDM schemes. With detailed prediction of maximum temperature rise and the corresponding peaking time by all the numerical schemes, effects of the change of radius of the gold nanosphere, the magnitude of fluence of laser, and laser irradiation with

  11. High Average Power, High Energy Short Pulse Fiber Laser System

    Energy Technology Data Exchange (ETDEWEB)

    Messerly, M J

    2007-11-13

    Recently continuous wave fiber laser systems with output powers in excess of 500W with good beam quality have been demonstrated [1]. High energy, ultrafast, chirped pulsed fiber laser systems have achieved record output energies of 1mJ [2]. However, these high-energy systems have not been scaled beyond a few watts of average output power. Fiber laser systems are attractive for many applications because they offer the promise of high efficiency, compact, robust systems that are turn key. Applications such as cutting, drilling and materials processing, front end systems for high energy pulsed lasers (such as petawatts) and laser based sources of high spatial coherence, high flux x-rays all require high energy short pulses and two of the three of these applications also require high average power. The challenge in creating a high energy chirped pulse fiber laser system is to find a way to scale the output energy while avoiding nonlinear effects and maintaining good beam quality in the amplifier fiber. To this end, our 3-year LDRD program sought to demonstrate a high energy, high average power fiber laser system. This work included exploring designs of large mode area optical fiber amplifiers for high energy systems as well as understanding the issues associated chirped pulse amplification in optical fiber amplifier systems.

  12. Pulse thermal energy transport/storage system

    Science.gov (United States)

    Weislogel, Mark M.

    1992-07-07

    A pulse-thermal pump having a novel fluid flow wherein heat admitted to a closed system raises the pressure in a closed evaporator chamber while another interconnected evaporator chamber remains open. This creates a large pressure differential, and at a predetermined pressure the closed evaporator is opened and the opened evaporator is closed. This difference in pressure initiates fluid flow in the system.

  13. Visualization and analysis of pulsed ion beam energy density profile with infrared imaging

    Science.gov (United States)

    Isakova, Y. I.; Pushkarev, A. I.

    2018-03-01

    Infrared imaging technique was used as a surface temperature-mapping tool to characterize the energy density distribution of intense pulsed ion beams on a thin metal target. The technique enables the measuring of the total ion beam energy and the energy density distribution along the cross section and allows one to optimize the operation of an ion diode and control target irradiation mode. The diagnostics was tested on the TEMP-4M accelerator at TPU, Tomsk, Russia and on the TEMP-6 accelerator at DUT, Dalian, China. The diagnostics was applied in studies of the dynamics of the target cooling in vacuum after irradiation and in the experiments with target ablation. Errors caused by the target ablation and target cooling during measurements have been analyzed. For Fluke Ti10 and Fluke Ti400 infrared cameras, the technique can achieve surface energy density sensitivity of 0.05 J/cm2 and spatial resolution of 1-2 mm. The thermal imaging diagnostics does not require expensive consumed materials. The measurement time does not exceed 0.1 s; therefore, this diagnostics can be used for the prompt evaluation of the energy density distribution of a pulsed ion beam and during automation of the irradiation process.

  14. Electro-optic measurement of terahertz pulse energy distribution

    NARCIS (Netherlands)

    Sun, J.H.; Gallacher, J.G.; Brussaard, G.J.H.; Lemos, N.; Issac, R.; Huang, Z.X.; Dias, J.M.; Jaroszynski, D.A.

    2009-01-01

    An accurate and direct measurement of the energy distribution of a low repetition rate terahertz electromagnetic pulse is challenging because of the lack of sensitive detectors in this spectral range. In this paper, we show how the total energy and energy density distribution of a terahertz

  15. TDDFT investigation of excitation of water tetramer under femtosecond laser pulse irradiation

    Science.gov (United States)

    Wang, Zhiping; Xu, Xuefen; Zhang, Fengshou; Qian, Chaoyi

    2018-04-01

    We study the static properties of water tetramer in ground state, the optical absorption spectra and ultrafast nonadiabatic dynamical response of water tetramer to short and intense laser pulses with different intensities by a real-space, real-time implementation of time-dependent density functional theory coupled to molecular dynamics (TDDFT-MD) nonadiabatically. The calculated results are in good agreement with available values in literature. Four typical irradiated scenarios of water tetramer in laser field, which are “normal vibration,” “break and reorganization,” “fragmentation and new formation” and “pure fragmentation”, are explored by discussing the ionization, the bond lengths of OH bonds and hydrogen bonds and the kinetic energy of ions. The dynamic simulation shows that the reaction channel of water tetramer can really be controlled by choosing appropriate laser parameters referring to the optical absorption spectra and hydrogen ions play an important role in the reaction channel. Furthermore, it is found that the laser intensity affects the kinetic energy of ejected protons more than that of the remaining fragments and all dynamic processes are somehow directly related to the velocity of departing protons.

  16. Electric conductivity of polyethylene during pulsed electron-beam irradiation at ETA

    International Nuclear Information System (INIS)

    Fiorito, R.B.; Miller, P.J.; Stern, S.H.

    1986-01-01

    The motivation for this work is two-fold: first, the authors want to understand the basic physics of the interaction of an intense electron beam with condensed matter. Intensity is the key word in the sense that many projectiles might act coherently or incoherently to alter significantly the medium through which they pass. During the pulse of an intense electron beam through a material which is ordinarily dielectric, the conductivity increases by 10 to 15 orders of magnitude. This effect is related to the promotion of charge carriers to the conduction band and to the mobility and lifetime of those carriers in that band. Therefore, there is a physically interesting system which is measurable in real time. It is a system which interrelates beam energy-deposition, charge-carrier concentration, material temperature, and carrier mobility. The second motivation for these experiments is methodological. If the authors can understand the relationship between conductivity and energy deposition, they might be able to develop this technique into a diagnostic of the dose-depth relationship in material subject to very-high dose and high dose-rate irradiation (≥ 1 Grad in ≤ 25 nsec). This relationship is inaccessible to measurement by means of conventional dosimetry. 14 references

  17. Bremsstrahlung γ-ray generation by electrons from gas jets irradiated by laser pulses for radiographic testing

    International Nuclear Information System (INIS)

    Oishi, Yuji; Nayuki, Takuya; Zhidkov, Alexei; Fujii, Takashi; Nemoto, Koshichi

    2012-01-01

    Electron generation from a gas jet irradiated by low energy femtosecond laser pulses is studied experimentally as a promising source of radiation for radioisotope-free γ-ray imaging systems. The calculated yield of γ-rays in the 0.5-2 MeV range, produced by low-average-power lasers and gas targets, exceeds the yields from solid tape targets up to 60 times. In addition, an effect of quasi-mono energetic electrons on γ-ray imaging is also discussed.

  18. Preventing Electromagnetic Pulse Irradiation Damage on Testis Using Selenium-rich Cordyceps Fungi. A Preclinical Study in Young Male Mice.

    Science.gov (United States)

    Miao, Xia; Wang, Yafeng; Lang, Haiyang; Lin, Yanyun; Guo, Qiyan; Yang, Mingjuan; Guo, Juan; Zhang, Yanjun; Zhang, Jie; Liu, Junye; Liu, Yaning; Zeng, Lihua; Guo, Guozhen

    2017-02-01

    Networked 21st century society, globalization, and communications technologies are paralleled by the rise of electromagnetic energy intensity in our environments and the growing pressure of the environtome on human biology and health. The latter is the entire complement of environmental factors, including the electromagnetic energy and the technologies that generate them, enacting on the digital citizen in the new century. Electromagnetic pulse (EMP) irradiation might have serious damaging effects not only on electronic equipment but also in the whole organism and reproductive health, through nonthermal effects and oxidative stress. We sought to determine whether EMP exposure (1) induces biological damage on reproductive health and (2) the extent to which selenium-rich Cordyceps fungi (daily coadministration) offer protection on the testicles and spermatozoa. In a preclinical randomized study, 3-week-old male BALB/c mice were repeatedly exposed to EMP (peak intensity 200 kV/m, pulse edge 3.5 ns, pulse width 15 ns, 0.1 Hz, and 400 pulses/day) 5 days per week for four consecutive weeks, with or without coadministration of daily selenium-rich Cordyceps fungi (100 mg/kg). Testicular index and spermatozoa formation were measured at baseline and 1, 7, 14, 28, and 60 day time points after EMP exposure. The group without Cordyceps cotreatment displayed decreased spermatozoa formation, shrunk seminiferous tubule diameters, and diminished antioxidative capacity at 28 and 60 days after exposure (p digital citizenship.

  19. Surface morphological modification of crosslinked hydrophilic co-polymers by nanosecond pulsed laser irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Primo, Gastón A.; Alvarez Igarzabal, Cecilia I. [IMBIV (CONICET), Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Edificio de Ciencias II, Ciudad Universitaria, Córdoba X5000HUA (Argentina); Pino, Gustavo A.; Ferrero, Juan C. [INFIQC (CONICET), Departamento de Fisicoquímica, Facultad de Ciencias Químicas, and Centro Láser de Ciencias Moleculares, Universidad Nacional de Córdoba, Córdoba X5000IUS (Argentina); Rossa, Maximiliano, E-mail: mrossa@fcq.unc.edu.ar [INFIQC (CONICET), Departamento de Fisicoquímica, Facultad de Ciencias Químicas, and Centro Láser de Ciencias Moleculares, Universidad Nacional de Córdoba, Córdoba X5000IUS (Argentina)

    2016-04-30

    Graphical abstract: - Highlights: • Laser-induced surface modification of crosslinked hydrophilic co-polymers by ns pulses. • Formation of ablation craters observed under most of the single-pulse experimental conditions. • UV laser foaming of dried hydrogel samples resulting from single- and multiple-pulse experiments. • Threshold values of the incident laser fluence reported for the observed surface modifications. • Lower threshold fluences for acrylate-based, compared to acrylamide-based hydrogels. - Abstract: This work reports an investigation of the surface modifications induced by irradiation with nanosecond laser pulses of ultraviolet and visible wavelengths on crosslinked hydrophilic co-polymeric materials, which have been functionalized with 1-vinylimidazole as a co-monomer. A comparison is made between hydrogels differing in the base co-monomer (N,N-dimethylaminoethyl methacrylate and N-[3-(dimethylamino)propyl] methacrylamide) and in hydration state (both swollen and dried states). Formation of craters is the dominant morphological change observed by ablation in the visible at 532 nm, whereas additional, less aggressive surface modifications, chiefly microfoams and roughness, are developed in the ultraviolet at 266 nm. At both irradiation wavelengths, threshold values of the incident laser fluence for the observation of the various surface modifications are determined under single-pulse laser irradiation conditions. It is shown that multiple-pulse irradiation at 266 nm with a limited number of laser shots can be used alternatively for generating a regular microfoam layer at the surface of dried hydrogels based on N,N-dimethylaminoethyl methacrylate. The observations are rationalized on the basis of currently accepted mechanisms for laser-induced polymer surface modification, with a significant contribution of the laser foaming mechanism. Prospective applications of the laser-foamed hydrogel matrices in biomolecule immobilization are suggested.

  20. Nanosecond pulsed laser nanostructuring of Au thin films: Comparison between irradiation at low and atmospheric pressure

    Energy Technology Data Exchange (ETDEWEB)

    Sánchez-Aké, C., E-mail: citlali.sanchez@ccadet.unam.mx [Centro de Ciencias Aplicadas y Desarrollo Tecnológico, Universidad Nacional Autónoma de México, Circuito Exterior S/N, C. U., Delegación Coyoacán, C.P. 04510, México D.F. (Mexico); Canales-Ramos, A. [Centro de Ciencias Aplicadas y Desarrollo Tecnológico, Universidad Nacional Autónoma de México, Circuito Exterior S/N, C. U., Delegación Coyoacán, C.P. 04510, México D.F. (Mexico); García-Fernández, T. [Universidad Autónoma de la Ciudad de México (UACM), Prolongación San Isidro 151, Col. San Lorenzo Tezonco, México D.F., C.P. 09790 (Mexico); Villagrán-Muniz, M. [Centro de Ciencias Aplicadas y Desarrollo Tecnológico, Universidad Nacional Autónoma de México, Circuito Exterior S/N, C. U., Delegación Coyoacán, C.P. 04510, México D.F. (Mexico)

    2017-05-01

    Highlights: • Background pressure plays an important role in NPs formation and its characteristics. • The NPs diameter and their size dispersion are smaller when irradiating in vacuum. • The plasmon resonance shifts ∼15 nm to higher frequencies when irradiating in vacuum. • Film partial ablation cannot be neglected for thickness in the range 40–80 nm. • In situ optical techniques monitor the timescale of the process and ablation dynamics. - Abstract: Au thin films with tens of nm in thickness deposited on glass substrates were irradiated with nanosecond UV (355 nm) laser pulses at atmospheric pressure and in vacuum conditions (∼600 and 10{sup −5} Torr). We studied the effect of the laser fluence (200–400 mJ/cm{sup 2}), thickness of the starting film (∼40–80 nm) and surrounding pressure on the partial ablation/evaporation of the films and the morphology of the produced nanoparticles (NPs). The dynamics of NPs formation was studied by measuring in real time the transmission of the samples upon continuous-wave laser exposure, and by means of probe beam deflection technique. The ejection of material from the film as a result of the irradiation was confirmed by time-resolved shadowgraphy technique. Experiments show that the NPs diameter and their size distribution are smaller when the irradiation is performed in vacuum regardless the laser fluence and thickness of the started film. It is also shown that the plasmon band shifts to higher frequencies with lower background pressure. The optical measurements show that the films melt and ablate during the laser pulse, but the transmission of the irradiated areas continues changing during tens of microseconds due to ejection of material and solidification of the remaining gold. Our results indicate that partial ablation cannot be neglected in nanostructuration by ns-pulsed irradiation of thin films when their thickness is in the studied range.

  1. Surface modification of LiNbO3 and KTa1-xNbxO3 crystals irradiated by intense pulsed ion beam

    Science.gov (United States)

    Cui, Xiaojun; Shen, Jie; Zhong, Haowen; Zhang, Jie; Yu, Xiao; Liang, Guoying; Qu, Miao; Yan, Sha; Zhang, Xiaofu; Le, Xiaoyun

    2017-10-01

    In this work, we studied the surface modification of LiNbO3 and KTa1-xNbxO3 irradiated by intense pulsed ion beam, which was mainly composed of H+ (70%) and Cn+ (30%) at an acceleration voltage of about 450 kV. The surface morphologies, microstructural evolution and elemental analysis of the sample surfaces after IPIB irradiation have been analyzed by scanning electron microscope, atomic force microscope, X-ray diffraction and energy dispersive spectrometer techniques, respectively. The results show that the surface morphologies have significant difference impacted by the irradiation effect. Regular gully damages range from 200 to 400 nm in depth appeared in LiNbO3 under 2 J/cm2 energy density for 1 pulse, block cracking appeared in KTa1-xNbxO3 at the same condition. Surface of the crystals have melted and were darkened with the increasing number up to 5 pulses. Crystal lattice arrangement is believed to be the dominant reason for the different experimental results irradiated by intense pulsed ion beam.

  2. A New Technique for SET Pulse Width Measurement in Chains of Inverters Using Pulsed Laser Irradiation

    International Nuclear Information System (INIS)

    Ferlet-Cavrois, V.; Fel, N.; Gaillardin, M.; Baggio, J.; Girard, S.; Flament, O.; Paillet, P.; McMorrow, D.; Melinger, J. S.; Kobayashi, D.; Hirose, K.; Saito, H.; Pouget, V.; Essely, F.; Schwank, J. R.; Flores, R. S.; Dodd, P. E.; Shaneyfelt, M. R.

    2009-01-01

    A new technique is developed to measure precisely and accurately the width of propagating voltage transients induced by irradiation of inverter chains. The technique is based on measurement of the supply current in a detection inverter, and permits a direct determination of the transient width with a 50 GHz bandwidth. (authors)

  3. Multi-time-scale heat transfer modeling of turbid tissues exposed to short-pulsed irradiations.

    Science.gov (United States)

    Kim, Kyunghan; Guo, Zhixiong

    2007-05-01

    A combined hyperbolic radiation and conduction heat transfer model is developed to simulate multi-time-scale heat transfer in turbid tissues exposed to short-pulsed irradiations. An initial temperature response of a tissue to an ultrashort pulse irradiation is analyzed by the volume-average method in combination with the transient discrete ordinates method for modeling the ultrafast radiation heat transfer. This response is found to reach pseudo steady state within 1 ns for the considered tissues. The single pulse result is then utilized to obtain the temperature response to pulse train irradiation at the microsecond/millisecond time scales. After that, the temperature field is predicted by the hyperbolic heat conduction model which is solved by the MacCormack's scheme with error terms correction. Finally, the hyperbolic conduction is compared with the traditional parabolic heat diffusion model. It is found that the maximum local temperatures are larger in the hyperbolic prediction than the parabolic prediction. In the modeled dermis tissue, a 7% non-dimensional temperature increase is found. After about 10 thermal relaxation times, thermal waves fade away and the predictions between the hyperbolic and parabolic models are consistent.

  4. Incubation behaviour in triazenepolymer thin films upon near-infrared femtosecond laser pulse irradiation

    International Nuclear Information System (INIS)

    Bonse, J; Wiggins, S M; Solis, J; Sturm, H; Urech, L; Wokaun, A; Lippert, T

    2007-01-01

    The effects of laser radiation induced by a sequence of ultrashort (130 fs), near-infrared (800 nm) Ti:sapphire laser pulses in ∼1 μm thick triazenepolymer films on glass substrates have been investigated by means of in-situ real-time reflectivity measurements featuring a ps-resolution streak camera and a ns-resolution photodiode set-up. The polymer films show incubation effects when each laser pulse in the sequence has a fluence below the single-pulse damage threshold. Non-damage conditions are maintained for several incubation pulses such that the reflectivity of the film shows a rapid decrease of up to 30% within 1 ns but subsequently recovers to its initial value on a ms timescale. Additional pulses lead to a permanent film damage. The critical number of laser pulses needed to generate a permanent damage of the film has been studied as a function of the laser fluence. Once damage is created, further laser pulses cause a partial removal of the film material from the glass substrate. Scanning force microscopy has been used to characterise ex-situ the irradiated surface areas. Based on these complementary measurements possible incubation mechanisms are discussed

  5. A Model for Microcontroller Functionality Upset Induced by External Pulsed Electromagnetic Irradiation

    Science.gov (United States)

    2016-11-21

    AFRL-RD-PS- AFRL-RD-PS- TN-2016-0003 TN-2016-0003 A Model for Microcontroller Functionality Upset Induced by External Pulsed Electromagnetic...TYPE Technical Note 3. DATES COVERED (From - To) 22-11-2015 – 21-11-2016 4. TITLE AND SUBTITLE A Model for Microcontroller Functionality Upset Induced by... microcontroller (µC) subjected to external irradiation by a narrowband electromagnetic (EM) pulse. In our model, the state of a µC is completely specified by

  6. Nano-pulsed laser irradiation scanning system for phase-change materials

    International Nuclear Information System (INIS)

    Kim, Sookyung; Li Xuezhe; Lee, Sangbin; Kim, Kyung-Ho; Lee, Seung-Yop

    2008-01-01

    Recently, the demand of a laser irradiation tester is increasing for phase change random access memory (PRAM) as well as conventional optical storage media. In this study, a nano-pulsed laser irradiation system is developed to characterize the optical property and writing performance of phase-change materials, based on a commercially available digital versatile disk (DVD) optical pick-up. The precisely controlled focusing and scanning on the material's surface are implemented using the auto-focusing mechanism and a voice coil motor (VCM) of the commercial DVD pick-up. The laser irradiation system provides various writing and reading functions such as adjustable laser power, pulse duration, recording pattern (spot, line and area), and writing/reading repetition, phase transition, and in situ reflectivity measurement before/after irradiation. Measurements of power time effect (PTE) diagram and reflectivity map of Ge 2 Sb 2 Te 5 samples show that the proposed laser irradiation system provides the powerful scanning tool to quantify the optical characteristics of phase-change materials

  7. Laser pulse propagation and enhanced energy coupling to fast electrons in dense plasma gradients

    International Nuclear Information System (INIS)

    Gray, R J; Carroll, D C; Yuan, X H; Brenner, C M; Coury, M; Quinn, M N; Tresca, O; McKenna, P; Burza, M; Wahlström, C-G; Lancaster, K L; Neely, D; Lin, X X; Li, Y T

    2014-01-01

    Laser energy absorption to fast electrons during the interaction of an ultra-intense (10 20 W cm −2 ), picosecond laser pulse with a solid is investigated, experimentally and numerically, as a function of the plasma density scale length at the irradiated surface. It is shown that there is an optimum density gradient for efficient energy coupling to electrons and that this arises due to strong self-focusing and channeling driving energy absorption over an extended length in the preformed plasma. At longer density gradients the laser filaments, resulting in significantly lower overall energy coupling. As the scale length is further increased, a transition to a second laser energy absorption process is observed experimentally via multiple diagnostics. The results demonstrate that it is possible to significantly enhance laser energy absorption and coupling to fast electrons by dynamically controlling the plasma density gradient. (paper)

  8. Effect of gamma irradiation on the fitness component of the pulse beetle, callosobruchus chinensis

    International Nuclear Information System (INIS)

    Abdelrahman, A.M.; Aboulnasr, A.E.; Roushdy, H.M.; Ahmed, M.Y.; Haiba, I.M.

    1984-01-01

    The present work deals with the fines components of the F 1 generation of pulse beetle, callosobruchus chinensis, developed from adults irradiated (as newly emerged adults) with higher doses and fractionation of sterilizing doses. The results obtained show a gradual decrease in egg production and hatchability. The dosages caused complete sterility in females and males respectively, shortening the life span of developed adults. The dose 200,000 rad caused immediate death to the irradiated adults. Fractionation of the sterilizing dose had no effect on either longevity or the percent of egg hatchability

  9. Shield gas induced cracks during nanosecond-pulsed laser irradiation of Zr-based metallic glass

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Hu; Noguchi, Jun; Yan, Jiwang [Keio University, Department of Mechanical Engineering, Faculty of Science and Technology, Yokohama (Japan)

    2016-10-15

    Laser processing techniques have been given increasing attentions in the field of metallic glasses (MGs). In this work, effects of two kinds of shield gases, nitrogen and argon, on nanosecond-pulsed laser irradiation of Zr-based MG were comparatively investigated. Results showed that compared to argon gas, nitrogen gas remarkably promoted the formation of cracks during laser irradiation. Furthermore, crack formation in nitrogen gas was enhanced by increasing the peak laser power intensity or decreasing the laser scanning speed. X-ray diffraction and micro-Raman spectroscopy indicated that the reason for enhanced cracks in nitrogen gas was the formation of ZrN. (orig.)

  10. Shield gas induced cracks during nanosecond-pulsed laser irradiation of Zr-based metallic glass

    Science.gov (United States)

    Huang, Hu; Noguchi, Jun; Yan, Jiwang

    2016-10-01

    Laser processing techniques have been given increasing attentions in the field of metallic glasses (MGs). In this work, effects of two kinds of shield gases, nitrogen and argon, on nanosecond-pulsed laser irradiation of Zr-based MG were comparatively investigated. Results showed that compared to argon gas, nitrogen gas remarkably promoted the formation of cracks during laser irradiation. Furthermore, crack formation in nitrogen gas was enhanced by increasing the peak laser power intensity or decreasing the laser scanning speed. X-ray diffraction and micro-Raman spectroscopy indicated that the reason for enhanced cracks in nitrogen gas was the formation of ZrN.

  11. High-current pulses from inductive energy stores

    International Nuclear Information System (INIS)

    Wipf, S.L.

    1981-01-01

    Superconducting inductive energy stores can be used for high power pulse supplies if a suitable current multiplication scheme is used. The concept of an inductive Marx generator is superior to a transformer. A third scheme, a variable flux linkage device, is suggested; in multiplying current it also compresses energy. Its function is in many ways analogous to that of a horsewhip. Superconductor limits indicate that peak power levels of TW can be reached for stored energies above 1 MJ

  12. Electron energy device for LINAC based Pulse Radiolysis Facility of RPCD

    International Nuclear Information System (INIS)

    Toley, M.A.; Shinde, S.J.; Chaudhari, B.B.; Sarkar, S.K.

    2015-07-01

    The pulse radiolysis facility is the experimental centerpiece of the radiation chemistry activities of the Radiation and Photochemistry Division (RPCD) of Bhabha Atomic Research Centre. This facility was created in 1986 which is based on a 7 MeV Linear Electron Accelerator (LINAC) procured from M/s Radiation Dynamics Ltd., UK. The electron energy is one of the principal parameters that influence the dose distribution within the sample irradiated with a beam of energetic electrons. An easy-to-use and robust device has been developed that can reliably detect day-today small variations in the beam energy. It consists of two identical aluminum plates except for their thickness, which are electrically insulated from each other. The thickness of each plate is carefully selected depending on the electron beam energy. The charge (or current) collected by each plate, under irradiation is measured. The ratio of the charge (or current) signal from the front plate to the sum of the signals from the front and rear plates is very sensitive to the beam energy. The high sensitivity and robustness make this device quite suitable for Electron energy measurement for Pulse radiolysis Facility at RPCD. (author)

  13. Pulse energy control through dual loop electronic feedback

    CSIR Research Space (South Africa)

    Jacobs, Cobus

    2006-07-01

    Full Text Available University of Stellenbosch WWW.LASER-RESEARCH.CO.ZA University of Stellenbosch Pulse Energy Control Through Dual Loop Electronic Feedback Cobus Jacobs, Steven Kriel Christoph Bollig, Thomas Jones Cobus Jacobs et al. Overview head2righthead2right...What is Laser Pulse Energy Control? head2righthead2rightWhy do we need it? head2righthead2rightHow do we get it? head2righthead2rightSimulation head2righthead2rightExperimental Setup head2righthead2rightResults Cobus Jacobs et al. head2righthead2right...

  14. Efficient delivery of 60 J pulse energy of long pulse Nd:YAG laser ...

    Indian Academy of Sciences (India)

    2014-02-09

    Feb 9, 2014 ... Most of today's industrial Nd:YAG lasers use fibre-optic beam delivery. ... optical fibre and successfully delivered up to 60 J of pulse energy with .... and electrical pump input to laser output conversion efficiency is about 5%. ... [3] W Koechner, Solid state laser engineering, 5th edn (Springer, Berlin, 1999).

  15. Microvascular blood flow dynamics associated with photodynamic therapy, pulsed dye laser irradiation and combined regimens

    OpenAIRE

    Smith, TK; Choi, B; Ramirez-San-Juan, JC; Nelson, JS; Osann, K; Kelly, KM

    2006-01-01

    Background and Objectives: Previous in vitro studies demonstrated the potential utility of benzoporphyrin derivative monoacid ring A (BPD) photodynamic therapy (PDT) for vascular destruction. Moreover, the effects of PDT were enhanced when this intervention was followed immediately by pulsed dye laser (PDL) irradiation (PDT/ PDL). We further evaluate vascular effects of PDT alone, PDL alone and PDT/PDL in an in vivo rodent dorsal skinfold model. Study Design/Materials and Methods: A dorsal sk...

  16. 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...

  17. Removing roughness on metal surface by irradiation of intense short-pulsed ion beams

    International Nuclear Information System (INIS)

    Hashimoto, Y.

    1995-01-01

    Surface modification of metals with an intense pulsed ion beam (IPIB) was studied experimentally. When the temperature rise of metal surfaces by IPIB irradiation exceeds their boiling point, it is found that machining roughness on surfaces is removed. The experiments were performed with the pulsed power generator HARIMA-II at Himeji Institute of Technology. The main components of the ion beam were carbon and fluorine ions. The IPIB was irradiated to metal plates (Al, Cu and Ti) which were placed at the focal point. Machining roughness on Ti surface was removed after IPIB irradiation, while roughness on Al and Cu plates was not removed. Using the present experimental parameters (beam power density: 32 W/cm 2 , pulse width: 25 ns), the temperature rise of the Ti surface was estimated to be 8,100 K which exceed its boiling point (3,000 K). However, the estimated temperatures of Al and Cu surfaces was 2,500 and 1,500 K, respectively, that are less than their boiling points. These studies above suggests that temperature rise over the boiling point of metals is necessary for removing machining roughness on metal surfaces

  18. Pulsed power inductive energy storage in the microsecond range

    International Nuclear Information System (INIS)

    Rix, W.; Miller, A.R.; Thompson, J.; Waisman, E.; Wilkinson, M.; Wilson, A.

    1993-01-01

    During the past five years Maxwell has developed a series of inductive energy storage (IES) pulsed power generators; ACE 1, ACE 2, ACE 3, and ACE 4, to drive electron-beam loads. They are all based on a plasma opening switch (POS) contained in a single vacuum envelope operating at conduction times of around one microsecond. They all employ fast capacitor bank technology to match this conduction time without intermediate power conditioning. Oil or air filled transmission lines transfer capacitor bank energy to a vacuum section where the final pulse compression is accomplished. Development of the ACE series is described, emphasizing capacitor bank and the opening switch technology for delivering high voltage, multimegampere pulses to electron beam loads

  19. 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

  20. Wavelength influence on nitrogen insertion into titanium by nanosecond pulsed laser irradiation in air

    Energy Technology Data Exchange (ETDEWEB)

    Torrent, F.; Lavisse, L. [Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB), UMR 6303 CNRS-Université de Bourgogne, 9 Av. A. Savary, BP 47 870, F-21078 Dijon Cedex (France); Berger, P. [CEA/DSM/IRAMIS/SIS2M, CEA-Saclay, F-91191 Gif sur Yvette (France); SIS2M, UMR CEA-CNRS 3299, CEA-Saclay, F-91191 Gif sur Yvette (France); Jouvard, J.-M.; Andrzejewski, H.; Pillon, G.; Bourgeois, S.; Marco de Lucas, M.C. [Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB), UMR 6303 CNRS-Université de Bourgogne, 9 Av. A. Savary, BP 47 870, F-21078 Dijon Cedex (France)

    2013-08-01

    We studied in this work the influence of the wavelength (532 vs. 1064 nm) on the insertion of nitrogen in titanium targets by surface laser treatments in air. The laser pulses were of 5 ns and the irradiance was lower than 25 × 10{sup 12} W/m{sup 2}. Results obtained using a frequency-doubled Nd:YAG laser at 532 nm were compared with those previously reported for laser treatments at 1064 nm. Nuclear reaction analysis and micro-Raman spectroscopy were used for determining the composition and the structure of the surface layers, respectively. Results showed the lower efficiency of irradiation at 532 nm for nitrogen insertion, which is possible only above threshold conditions depending on both the laser irradiance and the number of cumulated impacts per point. This was explained as being due to a higher ablative effect in the visible range. The insertion of oxygen giving rise to the growth of titanium oxynitrides was also discussed.

  1. Quantum energy duplication using super high output pulse laser

    International Nuclear Information System (INIS)

    Sugisaki, Kiwamu; Koyama, Kazuyoshi; Tanimoto, Mitsumori; Saito, Naoaki

    2000-01-01

    This study aims at elucidation on phenomena induced by strong electric field of super high output ultra short laser pulse to carry out development of basic technology required for promotion of a study on generation of high energy particle and photon using them, in order to contribute to application of super high output ultra short laser pulse and high energy plasma formed by it. In 1998 fiscal year of the last fiscal year in this study, by intending to increase the output by narrowing pulse width of the super high output laser, some basic experiments such as verification due to experiment on relativity theoretical self-convergence, generation of high energy particles, and so forth were carried out to establish a forecasting on future application. And, by conducting plasma generation experiment, self-guide and high energy particle formation experiment in plasma of super high intensity laser pulse important for its applications, and so forth, various technologies constituting foundation of future developments were developed, and more results could be obtained than those at proposal of this study. (G.K.)

  2. Selective Area Modification of Silicon Surface Wettability by Pulsed UV Laser Irradiation in Liquid Environment.

    Science.gov (United States)

    Liu, Neng; Moumanis, Khalid; Dubowski, Jan J

    2015-11-09

    The wettability of silicon (Si) is one of the important parameters in the technology of surface functionalization of this material and fabrication of biosensing devices. We report on a protocol of using KrF and ArF lasers irradiating Si (001) samples immersed in a liquid environment with low number of pulses and operating at moderately low pulse fluences to induce Si wettability modification. Wafers immersed for up to 4 hr in a 0.01% H2O2/H2O solution did not show measurable change in their initial contact angle (CA) ~75°. However, the 500-pulse KrF and ArF lasers irradiation of such wafers in a microchamber filled with 0.01% H2O2/H2O solution at 250 and 65 mJ/cm(2), respectively, has decreased the CA to near 15°, indicating the formation of a superhydrophilic surface. The formation of OH-terminated Si (001), with no measurable change of the wafer's surface morphology, has been confirmed by X-ray photoelectron spectroscopy and atomic force microscopy measurements. The selective area irradiated samples were then immersed in a biotin-conjugated fluorescein-stained nanospheres solution for 2 hr, resulting in a successful immobilization of the nanospheres in the non-irradiated area. This illustrates the potential of the method for selective area biofunctionalization and fabrication of advanced Si-based biosensing architectures. We also describe a similar protocol of irradiation of wafers immersed in methanol (CH3OH) using ArF laser operating at pulse fluence of 65 mJ/cm(2) and in situ formation of a strongly hydrophobic surface of Si (001) with the CA of 103°. The XPS results indicate ArF laser induced formation of Si-(OCH3)x compounds responsible for the observed hydrophobicity. However, no such compounds were found by XPS on the Si surface irradiated by KrF laser in methanol, demonstrating the inability of the KrF laser to photodissociate methanol and create -OCH3 radicals.

  3. Pulsed power drivers for ICF and high energy density physics

    International Nuclear Information System (INIS)

    Ramirez, J.J.; Matzen, M.K.; McDaniel, D.H.

    1995-01-01

    Nanosecond Pulsed Power Science and Technology has its origins in the 1960s and over the past decade has matured into a flexible and robust discipline capable of addressing key physics issues of importance to ICF and high Energy Density Physics. The major leverage provided by pulsed power is its ability to generate and deliver high energy and high power at low cost and high efficiency. A low-cost, high-efficiency driver is important because of the very large capital investment required for multi-megajoule ignition-class systems. High efficiency is of additional importance for a commercially viable inertial fusion energy option. Nanosecond pulsed power has been aggressively and successfully developed at Sandia over the past twenty years. This effort has led to the development of unique multi-purpose facilities supported by highly capable diagnostic, calculational and analytic capabilities. The Sandia Particle-beam Fusion Program has evolved as part of an integrated national ICF Program. It applies the low-cost, high-efficiency leverage provided by nanosecond pulsed power systems to the longer-term goals of the national program, i.e., the Laboratory Microfusion Facility and Inertial Fusion Energy. A separate effort has led to the application of nanosecond pulsed power to the generation of intense, high-energy laboratory x-ray sources for application to x-ray laser and radiation effects science research. Saturn is the most powerful of these sources to date. It generates ∼500 kilojoules of x-rays from a magnetically driven implosion (Z-pinch). This paper describes results of x-ray physics experiments performed on Saturn, plans for a new Z-pinch drive capability for PBFA-II, and a design concept for the proposed ∼15 MJ Jupiter facility. The opportunities for ICF-relevant research using these facilities will also be discussed

  4. Progress in developing repetitive pulse systems utilizing inductive energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Honig, E.M.

    1983-01-01

    High-power, fast-recovery vacuum switches were used in a new repetitive counterpulse and transfer circuit to deliver a 5-kHz pulse train with a peak power of 75 MW (at 8.6 kA) to a 1-..cap omega.. load, resulting in the first demonstration of fully controlled, high-power, high-repetition-rate operation of an inductive energy-storage and transfer system with nondestructive switches. New circuits, analytical and experimental results, and feasibility of 100-kV repetitive pulse generation are discussed. A new switching concept for railgun loads is presented.

  5. Electromagnetic-implosion generation of pulsed high energy density plasma

    International Nuclear Information System (INIS)

    Baker, W.L.; Broderick, N.F.; Degnan, J.H.; Hussey, T.W.; Kiuttu, G.F.; Kloc, D.A.; Reinovsky, R.E.

    1983-01-01

    This chapter reports on the experimental and theoretical investigation of the generation of pulsed high-energy-density plasmas by electromagnetic implosion of cylindrical foils (i.e., imploding liners or hollow Z-pinches) at the Air Force Weapons Laboratory. Presents a comparison of experimental data with one-dimensional MHD and two-dimensional calculations. Points out that the study is distinct from other imploding liner efforts in that the approach is to produce a hot, dense plasma from the imploded liner itself, rather than to compress a magnetic-field-performed plasma mixture. The goal is to produce an intense laboratory pulsed X-ray source

  6. Energy detection UWB system based on pulse width modulation

    Directory of Open Access Journals (Sweden)

    Song Cui

    2014-05-01

    Full Text Available A new energy detection ultra-wideband system based on pulse width modulation is proposed. The bit error rate (BER performance of this new system is slightly worst than that of a pulse position modulation (PPM system in additive white Gaussian noise channels. In multipath channels, this system does not suffer from cross-modulation interference as PPM, so it can achieve better BER performance than PPM when cross-modulation interference occurs. In addition, when synchronisation errors occur, this system is more robust than PPM.

  7. A Skin-attachable Flexible Piezoelectric Pulse Wave Energy Harvester

    International Nuclear Information System (INIS)

    Yoon, Sunghyun; Cho, Young-Ho

    2014-01-01

    We present a flexible piezoelectric generator, capable to harvest energy from human arterial pulse wave on the human wrist. Special features and advantages of the flexible piezoelectric generator include the multi-layer device design with contact windows and the simple fabrication process for the higher flexibility with the better energy harvesting efficiency. We have demonstrated the design effectiveness and the process simplicity of our skin- attachable flexible piezoelectric pulse wave energy harvester, composed of the sensitive P(VDF-TrFE) piezoelectric layer on the flexible polyimide support layer with windows. We experimentally characterize and demonstrate the energy harvesting capability of 0.2∼1.0μW in the Human heart rate range on the skin contact area of 3.71cm 2 . Additional physiological and/or vital signal monitoring devices can be fabricated and integrated on the skin attachable flexible generator, covered by an insulation layer; thus demonstrating the potentials and advantages of the present device for such applications to the flexible multi-functional selfpowered artificial skins, capable to detect physiological and/or vital signals on Human skin using the energy harvested from arterial pulse waves

  8. Nanocomposite oxide thin films grown by pulsed energy beam deposition

    International Nuclear Information System (INIS)

    Nistor, M.; Petitmangin, A.; Hebert, C.; Seiler, W.

    2011-01-01

    Highly non-stoichiometric indium tin oxide (ITO) thin films were grown by pulsed energy beam deposition (pulsed laser deposition-PLD and pulsed electron beam deposition-PED) under low oxygen pressure. The analysis of the structure and electrical transport properties showed that ITO films with a large oxygen deficiency (more than 20%) are nanocomposite films with metallic (In, Sn) clusters embedded in a stoichiometric and crystalline oxide matrix. The presence of the metallic clusters induces specific transport properties, i.e. a metallic conductivity via percolation with a superconducting transition at low temperature (about 6 K) and the melting and freezing of the In-Sn clusters in the room temperature to 450 K range evidenced by large changes in resistivity and a hysteresis cycle. By controlling the oxygen deficiency and temperature during the growth, the transport and optical properties of the nanocomposite oxide films could be tuned from metallic-like to insulating and from transparent to absorbing films.

  9. Effect of counter electric field during the irradiation of pulsed x-ray on the after-pulses of GM counter

    International Nuclear Information System (INIS)

    Igarashi, Ryuji; Narita, Yuichi; Ozawa, Yasutomo.

    1979-01-01

    The authors once made it clear by using pulsed radiation that the number of spurious discharge generation in organic gas-quenching type GM counters depends on the intensity of incident radiation. This spurious discharge is peculiar to the organic gas-quenching type GM counters, which the authors named after-pulses. The present study has been carried out to find the experimental conditions to verify the delayed generation mechanism of such after-pulses in bipolar GM tubes and the conditions to give the maximum number of after-pulses generation. For this purpose, a large low electric field region, whose field intensity is variable, should be provided in the tubes. Since it has been generally impossible in the bipolar GM tubes, the provision of that region transiently has been tried. The effect of the intensity of electric field in GM tubes during irradiation on the generation of after-pulses has been investigated by changing radiation intensity, anode voltage, and irradiated position. Consideration of the results has revealed that the number of after-pulse generation can be increased by forming transient low electric field region in the bipolar GM counters of organic gas-quenching type. It was the new knowledge that the transient anode voltage to maximize the after-pulse generating factor was several tens of negative voltage even if the conditions were varied. It seems that this fact depends upon the voltage giving the conditions to maximize the probability of forming after-pulse factors. (Wakatsuki, Y.)

  10. [Effect of electromagnetic pulse irradiation on structure and function of Leydig cells in mice].

    Science.gov (United States)

    Wang, Shui-Ming; Wang, De-Wen; Peng, Rui-Yun; Gao, Ya-Bing; Yang, Yi; Hu, Wen-Hua; Chen, Hao-Yu; Zhang, You-Ren; Gao, Yan

    2003-08-01

    To explore the effect of electromagnetic pulse (EMP) irradiation on structure and function of Leydig cells in mice. One hundred and fourteen male Kunming mice were randomly divided into irradiated and control group, the former radiated generally by 8 x 10(3) V/m, 2 x 10(4) V/m and 6 x 10(4) V/m EMP respectively five times within two minutes. Pathological changes of Leydig cells were observed by light and electron microscope. Serum testosterone (T), luteinizing hormone (LH) and estradiol (E2) were measured dynamically by radioimmunoassay at 6 h, 1 d, 3 d, 7 d, 14 d and 28 d after irradiation. Main pathological changes were edema and vacuolation, swelling of cytoplasmic mitochondria, reduce of lipid droplets, pale staining of most of lipid droplets, and partial or complete cavitation of lipid droplets in Leydig cells within 28 days after EMP radiation. Compared with normal controls, serum T decreased in all in different degrees within 28 days, and dropped significantly at 6 h-14 d, 6 h-7 d and 1 d-28 d after 8 x 10(3) V/m, 2 x 10(4) V/m and 6 x 10(4) V/m EMP irradiation(P < 0.05 or P < 0.01). EMP irradiation caused no significant changes in serum LH and E2. Leydig cells are among those that are the most susceptible to EMP irradiation. EMP irradiation may cause significant injury in structure and function of Leydig cells in mice, whose earlier and continuous effect is bound to affect sexual function and sperm production.

  11. Lowering effect of radioactive irradiation on breakdown voltage and electron avalanche pulse characteristics

    International Nuclear Information System (INIS)

    Kawahashi, Akira; Nakano, Toru; Hosokawa, Tatsuzo; Miyoshi, Yosinori.

    1976-01-01

    In the time resolving measurement of the growing process and breakdown of electron avalanche in a gap of uniform electric field, the phenomenon that DC breakdown voltage slightly lowered was observed when β ray was irradiated as the initial electron source, as compared with unirradiated condition. Beta source used is 90 Sr- 90 Y of 2 mCi in radiative equilibrium. The experimental results and the examination are described in detail. In brief, the remarkable superposition of succeeding avalanche pulse over the preceeding avalanche pulse waveform was observed under the gap condition in which the breakdown voltage decreased in β-ray irradiation. Thus this superposition of avalanche pulses is considered as one of the causes of the breakdown voltage reduction. When β source is used as the initial electron source, the number of supplied initial electrons is very large as compared with unity, and at the same time, a great number of initial electrons can be supplied within the diffusion radius r of avalanche. Then the effect of initial electron number n 0 was considered by employing a diagram for breakdown scheme. The transition from Townsend type breakdown to streamer type breakdown occurs owing to increasing n 0 , and in that condition, the breakdown voltage lowers slightly. (Wakatsuki, Y)

  12. Perspectives for online analysis of raw material by pulsed neutron irradiation

    Science.gov (United States)

    Bach, Pierre; Le Tourneur, P.; Poumarede, B.

    1997-02-01

    On-line analysis by pulsed neutron irradiation is an example of an advanced technology application of nuclear techniques, concerning real problems in the cement, mineral and coal industries. The most significant of these nuclear techniques is their capability of continuous measurement without contact and without sampling, which can lead to improved control of processes and resultant large financial savings. Compared to Californium neutron sources, the use of electrical pulsed neutron generators allows to obtain a higher signal/noise ratio for a more sensitive measurement, and allows to overcome a number of safety problems concerning transportation, installation and maintenance. An experiment related to a possible new on-line raw material analyzer is described, using a pulsed neutron generator. The key factors contributing to an accurate measurement are related to a suitable generator, to a high count rate gamma ray spectroscopy electronics, and to computational tools. Calculation and results for the optimization of the neutron irradiation time diagram are reported. One of the operational characteristics of such an equipment is related to neutron flux available: it is possible to adjust it to the requested accuracy, i.e. for a high accuracy during a few hours/day and for a lower accuracy the rest of the time. This feature allows to operate the neutron tube during a longer time, and then to reduce the cost of analysis.

  13. A thermodynamic model of plasma generation by pulsed laser irradiation in vacuum

    CERN Document Server

    Tosto, S

    2003-01-01

    This paper introduces a thermodynamic model to determine composition, temperature and pressure of the plasma cloud induced by pulsed laser irradiation in the case where a relevant thermal sputtering mechanism is operating at the surface of a molten layer. The model concerns in particular pulse lengths of the order of several nanoseconds and completes the results of a previous paper concerning the physics of the evaporation and boiling driven thermal sputtering (Tosto S 2002 J. Phys. D: Appl. Phys. 35); the recession rate and temperature at the molten surface are linked to the pulse fluence and plasma properties in the frame of a unique physical model. This paper shows that the plasma properties depend critically on the non-equilibrium character of the surface evaporation and boiling mechanisms. The extension of the model to the case of continuous laser irradiation is also discussed. Some examples of computer simulation aim to show the results available in the particular case of a metal target; the comparison ...

  14. Influence of gamma irradiation, cold storage and pulsing on post harvest life and respiration rate of 'golden gate' cut roses

    International Nuclear Information System (INIS)

    Palanikumar, S.; Vinod Kumar; Bhattacharjee, S.K.; Pal, Madan

    2003-01-01

    Gamma irradiation at 0.025 kGy increased the respiration rate of 'Golden Gate' cut roses. The irradiation followed by cold storage (at 4 deg C) brought down the respiration rate after storage duration of 3 days. The respiration rate was found maximum in the sucrose (3% ) pulsed flowers immediately after pulsing. However, the rate of respiration is decreased in all the treatments. The irradiated flowers recorded lowest amount of respiration at senescence and the vase life was maximum in these flowers. (author)

  15. Laser ablation of UHMWPE-polyethylene by 438 nm high energy pulsed laser

    Energy Technology Data Exchange (ETDEWEB)

    Torrisi, L.; Gammino, S.; Mezzasalma, A.M.; Visco, A.M.; Badziak, J.; Parys, P.; Wolowski, J.; Woryna, E.; Krasa, J.; Laska, L.; Pfeifer, M.; Rohlena, K.; Boody, F.P

    2004-04-15

    Pulsed laser ablation of ultra-high-molecular-weight-polyethylene (UHMWPE) is investigated at Prague Asterix Laser System (PALS) Laboratory. The high ablation yield as a function of laser energy is presented at 438 nm laser wavelength. The mechanisms of the polymer ablation are studied on the base of ''in situ'' analysis, such as mass quadrupole spectrometry and time-of-flight measurements, and ''ex situ'' analysis, such as SEM investigations and Raman spectroscopy. Results show that the laser irradiation induces a strong polymer dehydrogenation and molecular emission due to different C{sub x}H{sub y} groups having high kinetic energy and high charge state. At a laser pulse energy of 150 J the H{sup +}, C{sup n+} ions (n=1 to 6) are emitted from the plasma with velocities of the order of 10{sup 8} cm/s, while the C{sub x}H{sub y} groups and the carbon clusters, detected up to C{sub 16}, have a velocity about one or two order magnitude lower. The laser ablation process produces a deep crater in the polymer, which depth depends on the laser pulse energy and it is of the order of 500 {mu}m. The crater volume increases with the laser pulse energy. Results demonstrated that the laser radiation modifies the polymer chains because dehydrogenated material and carbon-like structures are detected in the crater walls and in the bottom of the crater, respectively. A comparison of the experimental results with the data available in literature is presented and discussed.

  16. Low-energy irradiation effects of gas cluster ion beams

    International Nuclear Information System (INIS)

    Houzumi, Shingo; Takeshima, Keigo; Mochiji, Kozo; Toyoda, Noriaki; Yamada, Isao

    2007-01-01

    A cluster-ion irradiation system with cluster-size selection has been developed to study the effects of the cluster size for surface processes using cluster ions. A permanent magnet with a magnetic field of 1.2 T is installed for size separation of large cluster ions. Trace formations at HOPG surface by the irradiation with size-selected Ar-cluster ions under acceleration energy of 30 keV were investigated by a scanning tunneling microscopy. Generation behavior of the crater-like traces is strongly affected by the number of constituent atoms (cluster size) of the irradiating cluster ion. When the incident cluster ion is composed of 100-3000 atoms, crater-like traces are observed on the irradiated surfaces. In contrast, such traces are not observed at all with the irradiation of the cluster-ions composed of over 5000 atoms. Such the behavior is discussed on the basis of the kinetic energy per constituent atom of the cluster ion. To study GCIB irradiation effects against macromolecule, GCIB was irradiated on DNA molecules absorbed on graphite surface. By the GCIB irradiation, much more DNA molecules was sputtered away as compared with the monomer-ion irradiation. (author)

  17. Dose controlled low energy electron irradiator for biomolecular films.

    Science.gov (United States)

    Kumar, S V K; Tare, Satej T; Upalekar, Yogesh V; Tsering, Thupten

    2016-03-01

    We have developed a multi target, Low Energy Electron (LEE), precise dose controlled irradiator for biomolecular films. Up to seven samples can be irradiated one after another at any preset electron energy and dose under UHV conditions without venting the chamber. In addition, one more sample goes through all the steps except irradiation, which can be used as control for comparison with the irradiated samples. All the samples are protected against stray electron irradiation by biasing them at -20 V during the entire period, except during irradiation. Ethernet based communication electronics hardware, LEE beam control electronics and computer interface were developed in house. The user Graphical User Interface to control the irradiation and dose measurement was developed using National Instruments Lab Windows CVI. The working and reliability of the dose controlled irradiator has been fully tested over the electron energy range of 0.5 to 500 eV by studying LEE induced single strand breaks to ΦX174 RF1 dsDNA.

  18. Dose controlled low energy electron irradiator for biomolecular films

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, S. V. K., E-mail: svkk@tifr.res.in; Tare, Satej T.; Upalekar, Yogesh V.; Tsering, Thupten [Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400 005 (India)

    2016-03-15

    We have developed a multi target, Low Energy Electron (LEE), precise dose controlled irradiator for biomolecular films. Up to seven samples can be irradiated one after another at any preset electron energy and dose under UHV conditions without venting the chamber. In addition, one more sample goes through all the steps except irradiation, which can be used as control for comparison with the irradiated samples. All the samples are protected against stray electron irradiation by biasing them at −20 V during the entire period, except during irradiation. Ethernet based communication electronics hardware, LEE beam control electronics and computer interface were developed in house. The user Graphical User Interface to control the irradiation and dose measurement was developed using National Instruments Lab Windows CVI. The working and reliability of the dose controlled irradiator has been fully tested over the electron energy range of 0.5 to 500 eV by studying LEE induced single strand breaks to ΦX174 RF1 dsDNA.

  19. Electron migration in hydrated biopolymers following pulsed irradiation at low temperatures

    International Nuclear Information System (INIS)

    Lith, D. van.

    1987-01-01

    Charge migration in biopolymer-water mixtures and the effect of water concentration on the charge migration is investigated by measuring the electrical conductivity and the light emission with the pulse radiolysis technique. A preliminary account of the microwave conductivity observed in hydrated DNA and collagen at low temperature after pulsed irradiation is given. The results show that when hydrated DNA or collagen are irradiated at low temperatures, conductivity transients with microsecond lifetime are observed. It is tentatively concluded that these transients are due to the highly mobile dry electron. The effect of water concentration on mobility, lifetime and migration distance of the electron is discussed. The effect of additives to the hydrated systems on the behaviour of the electron is described. It is shown that the observed effects of the additives confirm the earlier conclusions that the dry electron is the species responsible for the radiation induced conductivity. The water concentration in the DNA- and collagen-systems could be varied only between zero and approximately fifty percent, due to inhomogeneities which occur at higher water concentrations. Experiments on gelatin, a biopolymer which forms homogeneous samples with levels of hydration varying from almost zero to 100% water (ice) are described. Both the radiation induced and the dark microwave conductivity have been studied as a function of water content. Preliminary results of a study of the light emission from pulse irradiated DNA-water mixtures are reported in an attempt to establish a relation between the observed electron migration and the formation of excited states via charge neutralization. (Auth.)

  20. Measurements of Electron Transport in Foils Irradiated with a Picosecond Time Scale Laser Pulse

    International Nuclear Information System (INIS)

    Brown, C. R. D.; Hoarty, D. J.; James, S. F.; Swatton, D.; Hughes, S. J.; Morton, J. W.; Guymer, T. M.; Hill, M. P.; Chapman, D. A.; Andrew, J. E.; Comley, A. J.; Shepherd, R.; Dunn, J.; Chen, H.; Schneider, M.; Brown, G.; Beiersdorfer, P.; Emig, J.

    2011-01-01

    The heating of solid foils by a picosecond time scale laser pulse has been studied by using x-ray emission spectroscopy. The target material was plastic foil with a buried layer of a spectroscopic tracer material. The laser pulse length was either 0.5 or 2 ps, which resulted in a laser irradiance that varied over the range 10 16 -10 19 W/cm 2 . Time-resolved measurements of the buried layer emission spectra using an ultrafast x-ray streak camera were used to infer the density and temperature conditions as a function of laser parameters and depth of the buried layer. Comparison of the data to different models of electron transport showed that they are consistent with a model of electron transport that predicts the bulk of the target heating is due to return currents.

  1. Overcoming High Energy Backgrounds at Pulsed Spallation Sources

    CERN Document Server

    Cherkashyna, Nataliia; DiJulio, Douglas D.; Khaplanov, Anton; Pfeiffer, Dorothea; Scherzinger, Julius; Cooper-Jensen, Carsten P.; Fissum, Kevin G.; Ansell, Stuart; Iverson, Erik B.; Ehlers, Georg; Gallmeier, Franz X.; Panzner, Tobias; Rantsiou, Emmanouela; Kanaki, Kalliopi; Filges, Uwe; Kittelmann, Thomas; Extegarai, Maddi; Santoro, Valentina; Kirstein, Oliver; Bentley, Phillip M.

    2015-01-01

    Instrument backgrounds at neutron scattering facilities directly affect the quality and the efficiency of the scientific measurements that users perform. Part of the background at pulsed spallation neutron sources is caused by, and time-correlated with, the emission of high energy particles when the proton beam strikes the spallation target. This prompt pulse ultimately produces a signal, which can be highly problematic for a subset of instruments and measurements due to the time-correlated properties, and different to that from reactor sources. Measurements of this background have been made at both SNS (ORNL, Oak Ridge, TN, USA) and SINQ (PSI, Villigen, Switzerland). The background levels were generally found to be low compared to natural background. However, very low intensities of high-energy particles have been found to be detrimental to instrument performance in some conditions. Given that instrument performance is typically characterised by S/N, improvements in backgrounds can both improve instrument pe...

  2. Pulsed TEA CO2 Laser Irradiation of Titanium in Nitrogen and Carbon Dioxide Gases

    Science.gov (United States)

    Ciganovic, J.; Matavulj, P.; Trtica, M.; Stasic, J.; Savovic, J.; Zivkovic, S.; Momcilovic, M.

    2017-12-01

    Surface changes created by interaction of transversely excited atmospheric carbon dioxide (TEA CO2) laser with titanium target/implant in nitrogen and carbon dioxide gas were studied. TEA CO2 laser operated at 10.6 μm, pulse length of 100 ns and fluence of ˜17 J/cm2 which was sufficient for inducing surface modifications. Induced changes depend on the gas used. In both gases the grain structure was produced (central irradiated zone) but its forms were diverse, (N2: irregular shape; CO2: hill-like forms). Hydrodynamic features at peripheral zone, like resolidified droplets, were recorded only in CO2 gas. Elemental analysis of the titanium target surface indicated that under a nitrogen atmosphere surface nitridation occurred. In addition, irradiation in both gases was followed by appearance of plasma in front of the target. The existence of plasma indicates relatively high temperatures created above the target surface offering a sterilizing effect.

  3. Theory of suppressing avalanche process of carrier in short pulse laser irradiated dielectrics

    Energy Technology Data Exchange (ETDEWEB)

    Deng, H. X., E-mail: hxdeng@uestc.edu.cn, E-mail: xtzu@uestc.edu.cn, E-mail: kaisun@umich.edu; Zu, X. T., E-mail: hxdeng@uestc.edu.cn, E-mail: xtzu@uestc.edu.cn, E-mail: kaisun@umich.edu; Xiang, X. [School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054 (China); Zheng, W. G.; Yuan, X. D. [Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); Sun, K., E-mail: hxdeng@uestc.edu.cn, E-mail: xtzu@uestc.edu.cn, E-mail: kaisun@umich.edu [Department of Materials Engineering and Sciences, University of Michigan, 413B Space Research Building, Ann Arbor, Michigan 48109-2143 (United States); Gao, F. [Pacific Northwest National Laboratory, P. O. Box 999, Richland, Washington 99352 (United States)

    2014-05-28

    A theory for controlling avalanche process of carrier during short pulse laser irradiation is proposed. We show that avalanche process of conduction band electrons (CBEs) is determined by the occupation number of phonons in dielectrics. The theory provides a way to suppress avalanche process and a direct judgment for the contribution of avalanche process and photon ionization process to the generation of CBEs. The obtained temperature dependent rate equation shows that the laser induced damage threshold of dielectrics, e.g., fused silica, increase nonlinearly with the decreases of temperature. Present theory predicts a new approach to improve the laser induced damage threshold of dielectrics.

  4. Anisotropy effect of crater formation on single crystal silicon surface under intense pulsed ion beam irradiation

    Science.gov (United States)

    Shen, Jie; Yu, Xiao; Zhang, Jie; Zhong, Haowen; Cui, Xiaojun; Liang, Guoying; Yu, Xiang; Huang, Wanying; Shahid, Ijaz; Zhang, Xiaofu; Yan, Sha; Le, Xiaoyun

    2018-04-01

    Due to the induced extremely fast thermal and dynamic process, Intense Pulsed Ion Beam (IPIB) is widely applied in material processing, which can bring enhanced material performance and surface craters as well. To investigate the craters' formation mechanism, a specific model was built with Finite Element Methods (FEM) to simulate the thermal field on irradiated single crystal silicon. The direct evidence for the existence of the simulated 6-fold rotational symmetric thermal distribution was provided by electron microscope images obtained on single crystal silicon. The correlation of the experiment and simulation is of great importance to understand the interaction between IPIB and materials.

  5. Visible and ultraviolet emission from pulse irradiated amorphous and polycrystalline H2O ice

    International Nuclear Information System (INIS)

    Freeman, C.G.; Quickenden, T.I.; Litjens, R.A.J.; Sangster, D.F.

    1984-01-01

    Luminescence peaking at 405 nm was observed when thin films of amorphous or polycrystalline ice at 97 K were irradiated with a pulsed beam of 0.53 MeV electrons. These emissions differed from the luminescence emitted by crystalline ice in that memory effects were not observed; the peak wavelengths were red shifted by approx.20 nm; and the half-lives were 6--9 ns instead of approx.400 ns. The emission spectra of polycrystalline ice samples produced by rapid deposition or by annealing amorphous ice were similar, but both had substantially lower intensities than amorphous ice spectra

  6. Transient responses of SFG spectra of D 2O ice/CO/Pt(1 1 1) interface with irradiation of ultra-short NIR pump pulses

    Science.gov (United States)

    Kubota, Jun; Wada, Akihide; Domen, Kazunari; Kano, Satoru S.

    2002-08-01

    The behavior of D 2O ice on CO/Pt(1 1 1) and Pt(1 1 1) under the irradiation of near-IR pulses (NIR) was studied by sum-frequency generation (SFG) spectroscopy. The peaks assigned to the O-D stretching modes of ice were obtained for the first 30 molecular layers on Pt(1 1 1). When the D2O/ CO/ Pt(1 1 1) was irradiated, the signal of D 2O was weakened after 500 ps, but that of CO was weakened immediately after the pumping. A similar time response was observed for the D 2O peak in D2O/ Pt(1 1 1) . The weakening of SFG is attributed to the broadening of bands due to thermal excitation. This indicates that the energy of the pump pulse is deposited on the Pt(1 1 1) surface and diffused into the layers of D 2O ice in the 500 ps timescale.

  7. Molecular dynamics simulation of shock wave and spallation phenomena in metal foils irradiated by femtosecond laser pulse

    Science.gov (United States)

    Zhakhovsky, Vasily; Demaske, Brian; Inogamov, Nail; Oleynik, Ivan

    2010-03-01

    Femtosecond laser irradiation of metals is an effective technique to create a high-pressure frontal layer of 100-200 nm thickness. The associated ablation and spallation phenomena can be studied in the laser pump-probe experiments. We present results of a large-scale MD simulation of ablation and spallation dynamics developing in 1,2,3μm thick Al and Au foils irradiated by a femtosecond laser pulse. Atomic-scale mechanisms of laser energy deposition, transition from pressure wave to shock, reflection of the shock from the rear-side of the foil, and the nucleation of cracks in the reflected tensile wave, having a very high strain rate, were all studied. To achieve a realistic description of the complex phenomena induced by strong compression and rarefaction waves, we developed new embedded atom potentials for Al and Au based on cold pressure curves. MD simulations revealed the complex interplay between spallation and ablation processes: dynamics of spallation depends on the pressure profile formed in the ablated zone at the early stage of laser energy absorption. It is shown that the essential information such as material properties at high strain rate and spall strength can be extracted from the simulated rear-side surface velocity as a function of time.

  8. Improving the bulk laser-damage resistance of KDP by baking and pulsed-laser irradiation

    International Nuclear Information System (INIS)

    Swain, J.E.; Stokowski, S.E.; Milam, D.; Rainer, F.

    1981-01-01

    Isolated bulk damage centers are produced when KDP crystals are irradiated by 1-ns 1064-nm pulses. We have tested about 100 samples and find the median threshold to be 7 J/cm 2 when the samples are irradiated only once at each test volume (1-on-1 tests). The median threshold increased to 11 J/cm 2 when the test volumes were first subjected to subthreshold laser irradiation (n-on-1 tests). We baked several crystals at temperatures from 110 to 165 0 C and remeasured their thresholds. Baking increased thresholds in some crystals, but did not change thresholds of others. The median threshold of baked crystals ranged from 8 to 10 J/cm 2 depending on the baking temperature. In crystals that had been baked, subthreshold irradiation produced a large change in the bulk damage threshold, and reduced the volume density of damage centers relative to the density observed in unbaked crystals. The data are summarized in the table

  9. Dual-scale nanoripple/nanoparticle-covered microspikes on silicon by femtosecond double pulse train irradiation in water

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Ge; Jiang, Lan [Laser Micro/Nano Fabrication Laboratory, School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081 (China); Li, Xin, E-mail: lixin02@bit.edu.cn [Laser Micro/Nano Fabrication Laboratory, School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081 (China); Xu, Yongda; Shi, Xuesong; Yan, Ruyu [Laser Micro/Nano Fabrication Laboratory, School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081 (China); Lu, Yongfeng [Department of Electrical Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588-0511 (United States)

    2017-07-15

    Highlights: • A simple method to fabricate dual-scale structures on silicon is proposed. • Nanoripple-covered or nanoparticle-covered microspikes are obtained on Si firstly. • They are obtained by temporally-shaped fs laser one-step irradiation in water. • Their application in SERS was proved with a high sensitivity of up to 10{sup 8}. - Abstract: Novel dual-scale structures were obtained by femtosecond double pulse train (subpulse delay Δt > 0 ps) one-step irradiating silicon in water. The dual-scale structures consist of microspikes of ∼2 μm width and ∼0.5 μm height, and nanoripples with a mean period of 146 nm or nanoparticles with a mean diameter of 90 nm which entirely cover on the microspikes, for linearly polarized or circularly polarized femtosecond laser respectively. The formation of dual-scale structures involves the following processes: (1) Continuously laser energy deposited at femtosecond to picosecond timescales within silicon surfaces and central regions, will result in enhanced capillary waves and thinner melted silicon layers. Hence, the microspikes can be induced at laser fluences below ablation threshold; (2) Later (>500–800 pulses), a mass of debris and bubbles produced will lead to the remarkably and uniformly scattering or shielding of subsequent incident laser energy. Hence, the nanostructures can be induced. The novel structures exhibit high-sensitive surface enhanced Raman scattering with an enhancement factor of 10{sup 8} for Rhodamine 6G detecting. Besides, the novel structures have application potentials in improving the silicon hydrophobicity, antireflection, etc.

  10. Energy constraints in pulsed phase control of chaos

    Energy Technology Data Exchange (ETDEWEB)

    Meucci, R., E-mail: riccardo.meucci@ino.it [Istituto Nazionale di Ottica, Consiglio Nazionale delle Ricerche, Largo E. Fermi 6, 50125 Firenze (Italy); Euzzor, S. [Istituto Nazionale di Ottica, Consiglio Nazionale delle Ricerche, Largo E. Fermi 6, 50125 Firenze (Italy); Zambrano, S. [Università Vita-Salute San Raffaele, Via Olgettina 58, 20132 Milano (Italy); Pugliese, E. [Istituto Nazionale di Ottica, Consiglio Nazionale delle Ricerche, Largo E. Fermi 6, 50125 Firenze (Italy); Dipartimento di Scienze della Terra, Università di Firenze, Via G. La Pira 4, 50100 Firenze (Italy); Francini, F. [Istituto Nazionale di Ottica, Consiglio Nazionale delle Ricerche, Largo E. Fermi 6, 50125 Firenze (Italy); Arecchi, F.T. [Istituto Nazionale di Ottica, Consiglio Nazionale delle Ricerche, Largo E. Fermi 6, 50125 Firenze (Italy); Università di Firenze, Firenze (Italy)

    2017-01-15

    Phase control of chaos is a powerful technique but little is known about its physical constraints, relevant for real systems. As a fact, it has not been explored whether this technique can also be applied when the controlling perturbation is not harmonic. Here we apply phase control on a driven double well Duffing oscillator using periodic rectangular pulsed perturbations instead of the classical sinusoidal perturbations. Experimental measurements and numerical simulations show that this kind of perturbation is also able to stabilize the chaotic orbits for an adequate selection of the phase. Furthermore, as the duty cycle of the perturbation (that is, the fraction of the time that the periodically pulsed control is active) is increased, two separate regimes occur. In the first one, the perturbations leading to stabilization of periodic solutions are of constant energy (taken as the product of the duty cycle and the amplitude) and in the second one, a saturation phenomenon occurs, implying that increasing energy values of the perturbations are wasted. Our results unveil the versatility of the pulsed phase control scheme and the importance of energy constraints.

  11. Energy constraints in pulsed phase control of chaos

    International Nuclear Information System (INIS)

    Meucci, R.; Euzzor, S.; Zambrano, S.; Pugliese, E.; Francini, F.; Arecchi, F.T.

    2017-01-01

    Phase control of chaos is a powerful technique but little is known about its physical constraints, relevant for real systems. As a fact, it has not been explored whether this technique can also be applied when the controlling perturbation is not harmonic. Here we apply phase control on a driven double well Duffing oscillator using periodic rectangular pulsed perturbations instead of the classical sinusoidal perturbations. Experimental measurements and numerical simulations show that this kind of perturbation is also able to stabilize the chaotic orbits for an adequate selection of the phase. Furthermore, as the duty cycle of the perturbation (that is, the fraction of the time that the periodically pulsed control is active) is increased, two separate regimes occur. In the first one, the perturbations leading to stabilization of periodic solutions are of constant energy (taken as the product of the duty cycle and the amplitude) and in the second one, a saturation phenomenon occurs, implying that increasing energy values of the perturbations are wasted. Our results unveil the versatility of the pulsed phase control scheme and the importance of energy constraints.

  12. Shock waves in water at low energy pulsed electric discharges

    International Nuclear Information System (INIS)

    Pinchuk, M E; Kolikov, V A; Rutberg, Ph G; Leks, A G; Dolinovskaya, R V; Snetov, V N; Stogov, A Yu

    2012-01-01

    Experimental results of shock wave formation and propagation in water at low energy pulsed electric discharges are presented. To study the hydrodynamic structure of the shock waves, the direct shadow optical diagnostic device with time resolution of 5 ns and spatial resolution of 0.1 mm was designed and developed. Synchronization of the diagnostic and electrodischarge units by the fast optocouplers was carried out. The dependences of shock wave velocities after breakdown of interelectrode gap for various energy inputs (at range of ≤1 J) into discharge were obtained. Based on the experimental results the recommendations for the adjustment parameters of the power supply and load were suggested.

  13. Modelling of the energy density deposition profiles of ultrashort laser pulses focused in optical media

    International Nuclear Information System (INIS)

    Vidal, F; Lavertu, P-L; Bigaouette, N; Moore, F; Brunette, I; Giguere, D; Kieffer, J-C; Olivie, G; Ozaki, T

    2007-01-01

    The propagation of ultrashort laser pulses in dense optical media is investigated theoretically by solving numerically the nonlinear Schroedinger equation. It is shown that the maximum energy density deposition as a function of the pulse energy presents a well-defined threshold that increases with the pulse duration. As a consequence of plasma defocusing, the maximum energy density deposition is generally smaller and the size of the energy deposition zone is generally larger for shorter pulses. Nevertheless, significant values of the energy density deposition can be obtained near threshold, i.e., at lower energy than for longer pulses

  14. Phonon transport in a curved aluminum thin film due to laser short pulse irradiation

    Science.gov (United States)

    Mansoor, Saad Bin; Yilbas, Bekir Sami

    2018-05-01

    Laser short-pulse heating of a curved aluminum thin film is investigated. The Boltzmann transport equation is incorporated to formulate the heating situation. A Gaussian laser intensity distribution is considered along the film arc and time exponentially decaying of pulse intensity is incorporated in the analysis. The governing equations of energy transport in the electron and lattice sub-systems are coupled through the electron-phonon coupling parameter. To quantify the phonon intensity distribution in the thin film, equivalent equilibrium temperature is introduced, which is associated with the average energy of all phonons around a local point when the phonon energies are redistributed adiabatically to an equilibrium state. It is found the numerical simulations that electron temperature follows similar trend to the spatial distribution of the laser pulse intensity at the film edge. Temporal variation of electron temperature does not follow the laser pulse intensity distribution. The rise of temperature in the electron sub-system is fast while it remains slow in the lattice sub-system.

  15. Bio-efficacy of gamma irradiation against pulse beetle, Callosobruchus maculatus L. infesting cowpea seeds

    International Nuclear Information System (INIS)

    Chauhan, Sumit Kumar; Bhalla, S.; Gautam, S.

    2015-01-01

    The pulse beetle, Callosobruchus maculatus is an important pest of cowpea in storage. It has cosmopolitan distribution with wide host range and also has different strains. It causes 20-60 per cent losses during storage of cowpea. Hazardous environmental effects posed by the chemicals used for its management necessitate the need for an alternative ecofriendly strategy to control the insect. Gamma irradiation seems to be a viable, non-chemical, residue-free, ecofriendly strategy. The experimental insect, C. maculatus was reared on the cowpea seeds under controlled conditions (28±1℃ and 65±5% RH). The freshly emerged adults (about 24-36 h of age) were exposed in very fine thin polythene envelops to gamma radiation at different doses viz., 25, 50, 100, 200, 400, 600 and 800 Gy using Cobalt-60 Gamma irradiation facility at Food Technology Division, Bhabha Atomic Research Centre, Trombay, Mumbai, India. The parameters observed included adult mortality, longevity, fecundity of the survivors and adult emergence in F1 generation. Dose dependent insect mortality was observed with immediate mortality at higher doses. High mortality was observed within 24 hour of irradiation. However, complete mortality resulted within five days of irradiation at 600 and 800 Gy as compared to 12 days in control. Adult longevity decreased with increase in radiation dose. The mean longevity decreased from 6.00 days in control to 2.48 days at the highest dose. The eggs laid by the treated adult beetles did not develop into the adults of next generation. Much higher doses were required to kill the adult while the complete sterility (100% sterility) was found even at the lowest dose of 25 Gy. Thus, gamma irradiation has potential to be used as an eco-friendly mitigation measure against C. maculatus. (author)

  16. Surface morphology, microstructure and properties of as-cast AZ31 magnesium alloy irradiated by high intensity pulsed ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Xuesong [State Key Laboratory of Robotics and System, Harbin Institute of Technology, Harbin 150080 (China); The Fourth Hospital of Harbin Medical University, Harbin 150001 (China); Zhang, Gang [Sino-Russia Joint Lab for High Energy Beam, Shenyang Ligong University, Shenyang 110159 (China); Wang, Guotian [School of Automobile and Traffic Engineering, Heilongjiang Institute of Technology, Harbin 150050 (China); Zhu, Guoliang, E-mail: glzhu1983@hotmail.com [Shanghai Key Laboratory of Advanced High-temperature Materials and Precision Forming, Shanghai Jiao Tong University, Dongchuan Road 800, 200240 Shanghai (China); Zhou, Wei, E-mail: wzhou@sjtu.edu.cn [Shanghai Key Laboratory of Advanced High-temperature Materials and Precision Forming, Shanghai Jiao Tong University, Dongchuan Road 800, 200240 Shanghai (China); Wang, Jun; Sun, Baode [Shanghai Key Laboratory of Advanced High-temperature Materials and Precision Forming, Shanghai Jiao Tong University, Dongchuan Road 800, 200240 Shanghai (China); The State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Dongchuan Road 800, 200240 Shanghai (China)

    2014-08-30

    Highlights: • High intensity pulsed ion beam (HIPIB) irradiation were performed to improve the properties of as-cast AZ31 magnesium alloy. • After 10 shots HIPIB irradiation, the average microhardness was increased by 27.1% and wear rate was reduced by 38.5%. • After 10 shots HIPIB irradiation, the corrosion rate was reduced by 24.8%, and the corrosion rate was decreased from 23.15 g m{sup −2} h{sup −1} to 17.4 g m{sup −2} h{sup −1}. - Abstract: High intensity pulsed ion beam (HIPIB) irradiation was performed as surface modification to improve the properties of as-cast AZ31 magnesium (Mg) alloys. The surface morphology and microstructure of the irradiated Mg alloys were characterized and their microhardness, wear resistance and corrosion resistance before and after HIPIB irradiation were measured. The results show that the formation of crater on the surface was attributed to the particles impacted from the irradiated cathode material. HIPIB irradiation resulted in more vacancy defects on the surface of the material. Moreover, new dislocations were generated by the reaction between vacancies, and the dislocation configuration was also changed. These variations caused by the HIPIB are beneficial for improving the material properties. After 10 shots of irradiation, the average microhardness increased by 27.1% but the wear rate decreased by 38.5%. The corrosion rate was reduced by 24.8% according to the salt spray corrosion experiment.

  17. Interaction of Repetitively Pulsed High Energy Laser Radiation With Matter

    Science.gov (United States)

    Hugenschmidt, Manfred

    1986-10-01

    The paper is concerned with laser target interaction processes involving new methods of improving the overall energy balance. As expected theoretically, this can be achieved with high repetition rate pulsed lasers even for initially highly reflecting materials, such as metals. Experiments were performed by using a pulsed CO2 laser at mean powers up to 2 kW and repetition rates up to 100 Hz. The rates of temperature rise of aluminium for example were thereby increased by lore than a factor of 3 as compared to cw-radiation of comparable power density. Similar improvements were found for the overall absorptivities that were increased by this method by more than an order of magnitude.

  18. 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

  19. High-Wattage Pulsed Irradiation of Linearly Polarized Near-Infrared Light to Stellate Ganglion Area for Burning Mouth Syndrome

    Directory of Open Access Journals (Sweden)

    Yukihiro Momota

    2014-01-01

    Full Text Available The purpose of this study was to apply high-wattage pulsed irradiation of linearly polarized near-infrared light to the stellate ganglion area for burning mouth syndrome (BMS and to assess the efficacy of the stellate ganglion area irradiation (SGR on BMS using differential time-/frequency-domain parameters (D parameters. Three patients with BMS received high-wattage pulsed SGR; the response to SGR was evaluated by visual analogue scale (VAS representing the intensity of glossalgia and D parameters used in heart rate variability analysis. High-wattage pulsed SGR significantly decreased the mean value of VAS in all cases without any adverse event such as thermal injury. D parameters mostly correlated with clinical condition of BMS. High-wattage pulsed SGR was safe and effective for the treatment of BMS; D parameters are useful for assessing efficacy of SGR on BMS.

  20. Reactions of H2O3 in the pulse-irradiated Fe(II)-O2 system

    DEFF Research Database (Denmark)

    Sehested, Knud; Bjergbakke, Erling; Lang Rasmussen, O.

    1969-01-01

    G(Fe(III)] is measured in pulse-irradiated O2-saturated solutions of 20 to 160 μMFe(II), at the p H's 0.46, 1.51, and 2.74 H2SO4 and HClO4 and with dose rates between 1 and 8 krad/1 μsec pulse. Based on homogeneous kinetics, the results are interpreted by a system of 18 reactions. The formation...

  1. The separated electric and magnetic field responses of luminescent bacteria exposed to pulsed microwave irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Catrin F., E-mail: williamscf@cardiff.ac.uk [School of Engineering, Cardiff University, Queen' s Buildings, Newport Road, Cardiff, CF24 3AA Wales (United Kingdom); School of Biosciences, Cardiff University, Main Building, Cathays Park, Cardiff, CF10 3AT Wales (United Kingdom); Geroni, Gilles M.; Pirog, Antoine; Lees, Jonathan; Porch, Adrian [School of Engineering, Cardiff University, Queen' s Buildings, Newport Road, Cardiff, CF24 3AA Wales (United Kingdom); Lloyd, David [School of Biosciences, Cardiff University, Main Building, Cathays Park, Cardiff, CF10 3AT Wales (United Kingdom)

    2016-08-29

    Electromagnetic fields (EMFs) are ubiquitous in the digital world we inhabit, with microwave and millimetre wave sources of non-ionizing radiation employed extensively in electronics and communications, e.g., in mobile phones and Wi-Fi. Indeed, the advent of 5G systems and the “internet of things” is likely to lead to massive densification of wireless networks. Whilst the thermal effects of EMFs on biological systems are well characterised, their putative non-thermal effects remain a controversial subject. Here, we use the bioluminescent marine bacterium, Vibrio fischeri, to monitor the effects of pulsed microwave electromagnetic fields, of nominal frequency 2.5 GHz, on light emission. Separated electric and magnetic field effects were investigated using a resonant microwave cavity, within which the maxima of each field are separated. For pulsed electric field exposure, the bacteria gave reproducible responses and recovery in light emission. At the lowest pulsed duty cycle (1.25%) and after short durations (100 ms) of exposure to the electric field at power levels of 4.5 W rms, we observed an initial stimulation of bioluminescence, whereas successive microwave pulses became inhibitory. Much of this behaviour is due to thermal effects, as the bacterial light output is very sensitive to the local temperature. Conversely, magnetic field exposure gave no measurable short-term responses even at the highest power levels of 32 W rms. Thus, we were able to detect, de-convolute, and evaluate independently the effects of separated electric and magnetic fields on exposure of a luminescent biological system to microwave irradiation.

  2. The separated electric and magnetic field responses of luminescent bacteria exposed to pulsed microwave irradiation

    Science.gov (United States)

    Williams, Catrin F.; Geroni, Gilles M.; Pirog, Antoine; Lloyd, David; Lees, Jonathan; Porch, Adrian

    2016-08-01

    Electromagnetic fields (EMFs) are ubiquitous in the digital world we inhabit, with microwave and millimetre wave sources of non-ionizing radiation employed extensively in electronics and communications, e.g., in mobile phones and Wi-Fi. Indeed, the advent of 5G systems and the "internet of things" is likely to lead to massive densification of wireless networks. Whilst the thermal effects of EMFs on biological systems are well characterised, their putative non-thermal effects remain a controversial subject. Here, we use the bioluminescent marine bacterium, Vibrio fischeri, to monitor the effects of pulsed microwave electromagnetic fields, of nominal frequency 2.5 GHz, on light emission. Separated electric and magnetic field effects were investigated using a resonant microwave cavity, within which the maxima of each field are separated. For pulsed electric field exposure, the bacteria gave reproducible responses and recovery in light emission. At the lowest pulsed duty cycle (1.25%) and after short durations (100 ms) of exposure to the electric field at power levels of 4.5 W rms, we observed an initial stimulation of bioluminescence, whereas successive microwave pulses became inhibitory. Much of this behaviour is due to thermal effects, as the bacterial light output is very sensitive to the local temperature. Conversely, magnetic field exposure gave no measurable short-term responses even at the highest power levels of 32 W rms. Thus, we were able to detect, de-convolute, and evaluate independently the effects of separated electric and magnetic fields on exposure of a luminescent biological system to microwave irradiation.

  3. The separated electric and magnetic field responses of luminescent bacteria exposed to pulsed microwave irradiation

    International Nuclear Information System (INIS)

    Williams, Catrin F.; Geroni, Gilles M.; Pirog, Antoine; Lees, Jonathan; Porch, Adrian; Lloyd, David

    2016-01-01

    Electromagnetic fields (EMFs) are ubiquitous in the digital world we inhabit, with microwave and millimetre wave sources of non-ionizing radiation employed extensively in electronics and communications, e.g., in mobile phones and Wi-Fi. Indeed, the advent of 5G systems and the “internet of things” is likely to lead to massive densification of wireless networks. Whilst the thermal effects of EMFs on biological systems are well characterised, their putative non-thermal effects remain a controversial subject. Here, we use the bioluminescent marine bacterium, Vibrio fischeri, to monitor the effects of pulsed microwave electromagnetic fields, of nominal frequency 2.5 GHz, on light emission. Separated electric and magnetic field effects were investigated using a resonant microwave cavity, within which the maxima of each field are separated. For pulsed electric field exposure, the bacteria gave reproducible responses and recovery in light emission. At the lowest pulsed duty cycle (1.25%) and after short durations (100 ms) of exposure to the electric field at power levels of 4.5 W rms, we observed an initial stimulation of bioluminescence, whereas successive microwave pulses became inhibitory. Much of this behaviour is due to thermal effects, as the bacterial light output is very sensitive to the local temperature. Conversely, magnetic field exposure gave no measurable short-term responses even at the highest power levels of 32 W rms. Thus, we were able to detect, de-convolute, and evaluate independently the effects of separated electric and magnetic fields on exposure of a luminescent biological system to microwave irradiation.

  4. A Study of Polycrystalline Silicon Damage Features Based on Nanosecond Pulse Laser Irradiation with Different Wavelength Effects

    OpenAIRE

    Xu, Jiangmin; Chen, Chao; Zhang, Tengfei; Han, Zhenchun

    2017-01-01

    Based on PVDF (piezoelectric sensing techniques), this paper attempts to study the propagation law of shock waves in brittle materials during the process of three-wavelength laser irradiation of polysilicon, and discusses the formation mechanism of thermal shock failure. The experimental results show that the vapor pressure effect and the plasma pressure effect in the process of pulsed laser irradiation lead to the splashing of high temperature and high density melt. With the decrease of the ...

  5. Time-resolved studies of ultrarapid solidification of highly undercooled molten silicon formed by pulsed laser irradiation

    International Nuclear Information System (INIS)

    Lowndes, D.H.; Jellison, G.E. Jr.; Wood, R.F.; Carpenter, R.

    1984-01-01

    This paper reports new results of nanosecond-resolution time-resolved optical reflectivity measurements, during pulsed excimer (KrF, 248 nm) laser irradiation of Si-implanted amorphous (a) silicon layers, which, together with model calculations and post-irradiation TEM measurements, have allowed us to study both the transformation of a-Si to a highly undercooled liquid (l) phase and the subsequent ultrarapid solidification process

  6. Energy transfer from an alkene triplet state during pulse radiolysis

    International Nuclear Information System (INIS)

    Barwise, A.J.G.; Gorman, A.A.; Rodgers, M.A.J.

    1976-01-01

    Pulse radiolysis of a benzene solution of norbornene containing low concentrations of anthracene results in delayed formation of anthracene triplet: this is the result of diffusion-controlled energy transfer from the alkene triplet state which has a natural lifetime in benzene of 250 ns. The use of various hydrocarbon acceptors has indicated that Esub(T)=20 000+-500 cm -1 for the relaxed T 1 state of the alkene, at least 5000 cm -1 below that of the spectroscopic state. (Auth.)

  7. Pulsed EPR study of low-dose irradiation effects in L-alanine crystals irradiated with γ-rays, Ne and Si ion beams

    International Nuclear Information System (INIS)

    Rakvin, B.; Maltar-Strmecki, N.; Nakagawa, K.

    2007-01-01

    Low-dose irradiation effects in L-alanine single crystals irradiated with γ-rays, Ne and Si ion beams have been investigated by means of a two-pulse electron spin echo (ESE) technique. An effective phase memory time, T M , was measured from the first stable L-alanine radical, SAR1, and its complex relaxation mechanism is discussed. Both spectral and instantaneous diffusion contributions to the total effective relaxation rate have been extrapolated through the detection of the two-pulse ESE signal as a function of turning angle. The local microscopic concentration of paramagnetic centers C(ions)/C(γ-ray) for low-dose heavy-ion irradiation has been deduced from the corresponding spin-spin interaction

  8. Stored energy in fusion magnet materials irradiated at low temperatures

    International Nuclear Information System (INIS)

    Chaplin, R.L.; Kerchner, H.R.; Klabunde, C.E.; Coltman, R.R.

    1989-08-01

    During the power cycle of a fusion reactor, the radiation reaching the superconducting magnet system will produce an accumulation of immobile defects in the magnet materials. During a subsequent warm-up cycle of the magnet system, the defects will become mobile and interact to produce new defect configurations as well as some mutual defect annihilations which generate heat-the release of stored energy. This report presents a brief qualitative discussion of the mechanisms for the production and release of stored energy in irradiated materials, a theoretical analysis of the thermal response of irradiated materials, theoretical analysis of the thermal response of irradiated materials during warm-up, and a discussion of the possible impact of stored energy release on fusion magnet operation 20 refs

  9. Efficiency of respiratory-gated delivery of synchrotron-based pulsed proton irradiation

    International Nuclear Information System (INIS)

    Tsunashima, Yoshikazu; Vedam, Sastry; Dong, Lei; Bues, Martin; Balter, Peter; Smith, Alfred; Mohan, Radhe; Umezawa, Masumi; Sakae, Takeji

    2008-01-01

    Significant differences exist in respiratory-gated proton beam delivery with a synchrotron-based accelerator system when compared to photon therapy with a conventional linear accelerator. Delivery of protons with a synchrotron accelerator is governed by a magnet excitation cycle pattern. Optimal synchronization of the magnet excitation cycle pattern with the respiratory motion pattern is critical to the efficiency of respiratory-gated proton delivery. There has been little systematic analysis to optimize the accelerator's operational parameters to improve gated treatment efficiency. The goal of this study was to estimate the overall efficiency of respiratory-gated synchrotron-based proton irradiation through realistic simulation. Using 62 respiratory motion traces from 38 patients, we simulated respiratory gating for duty cycles of 30%, 20% and 10% around peak exhalation for various fixed and variable magnet excitation patterns. In each case, the time required to deliver 100 monitor units in both non-gated and gated irradiation scenarios was determined. Based on results from this study, the minimum time required to deliver 100 MU was 1.1 min for non-gated irradiation. For respiratory-gated delivery at a 30% duty cycle around peak exhalation, corresponding average delivery times were typically three times longer with a fixed magnet excitation cycle pattern. However, when a variable excitation cycle was allowed in synchrony with the patient's respiratory cycle, the treatment time only doubled. Thus, respiratory-gated delivery of synchrotron-based pulsed proton irradiation is feasible and more efficient when a variable magnet excitation cycle pattern is used

  10. Low energy He+ irradiation effect on graphite surface

    International Nuclear Information System (INIS)

    Asari, E.; Nakamura, K.G.; Kitajima, M.; Kawabe, T.

    1992-01-01

    Study on the lattice disordering and the secondary electron emission under low energy (1-5keV) He + irradiation is reported. Real-time Raman measurements show that difference in the observed Raman spectra for different ion energies is due to the difference of the damage depth. The relation between the observed Raman spectrum and the depth profile of lattice damage is discussed. Energy dependence of the secondary electron emission coefficient are also described. (author)

  11. A high energy density relaxor antiferroelectric pulsed capacitor dielectric

    Energy Technology Data Exchange (ETDEWEB)

    Jo, Hwan Ryul; Lynch, Christopher S. [Department of Mechanical and Aerospace Engineering, University of California, Los Angeles (UCLA), Los Angeles, California 90095 (United States)

    2016-01-14

    Pulsed capacitors require high energy density and low loss, properties that can be realized through selection of composition. Ceramic (Pb{sub 0.88}La{sub 0.08})(Zr{sub 0.91}Ti{sub 0.09})O{sub 3} was found to be an ideal candidate. La{sup 3+} doping and excess PbO were used to produce relaxor antiferroelectric behavior with slim and slanted hysteresis loops to reduce the dielectric hysteresis loss, to increase the dielectric strength, and to increase the discharge energy density. The discharge energy density of this composition was found to be 3.04 J/cm{sup 3} with applied electric field of 170 kV/cm, and the energy efficiency, defined as the ratio of the discharge energy density to the charging energy density, was 0.920. This high efficiency reduces the heat generated under cyclic loading and improves the reliability. The properties were observed to degrade some with temperature increase above 80 °C. Repeated electric field cycles up to 10 000 cycles were applied to the specimen with no observed performance degradation.

  12. EDF energy generation UK transport of irradiated fuel

    Energy Technology Data Exchange (ETDEWEB)

    James, R. [EDF Energy, London, (United Kingdom)

    2015-07-01

    This paper give an overview of irradiated fuel transport in the UK. It describes the design of irradiated fuel flask used by EDF Energy; operational experience and good practices learnt from over 50 years of irradiated fuel transport. The AGRs can store approximately 9 months generation of spent fuel, hence the ability to transport irradiated fuel is vital. Movements are by road to the nearest railhead, typically less than 2 miles and then by rail to Sellafield, up to 400 miles, for reprocessing or long term storage. Road and rail vehicles are covered. To date in the UK: over 30,000 Magnox flask journeys and over 15,000 AGR A2 flask journeys have been carried out.

  13. Erosion of CFC, pyrolytic and boronated graphite under short pulsed laser irradiation

    International Nuclear Information System (INIS)

    Kraaij, G.J.; Bakker, J.; Stad, R.C.L. van der

    1992-07-01

    The effect of short pulsed laser irradiation of '0/3' ms and up to 10 MJ/m 2 on different types of carbon base materials is described. These materials are investigated as candidate protection materials for the Plasma Facing Components of NET/ITER. These materials are: carbon fibre composite graphite, pyrolytic graphite and boronated graphite. The volume of the laser induced craters was measured with an optical topographic scanner, and these data are evaluated with a simple model for the erosion. As a results, the enthalpy of ablation is estimated as 30±3 MJ/kg. A comparison is made with finite element numerical calculations, and the effect of lateral heat transfer is estimated using an analytical model. (author). 8 refs., 23 figs., 4 tabs

  14. The tensile effect on crack formation in single crystal silicon irradiated by intense pulsed ion beam

    Science.gov (United States)

    Liang, Guoying; Shen, Jie; Zhang, Jie; Zhong, Haowen; Cui, Xiaojun; Yan, Sha; Zhang, Xiaofu; Yu, Xiao; Le, Xiaoyun

    2017-10-01

    Improving antifatigue performance of silicon substrate is very important for the development of semiconductor industry. The cracking behavior of silicon under intense pulsed ion beam irradiation was studied by numerical simulation in order to understand the mechanism of induced surface peeling observed by experimental means. Using molecular dynamics simulation based on Stillinger Weber potential, tensile effect on crack growth and propagation in single crystal silicon was investigated. Simulation results reveal that stress-strain curves of single crystal silicon at a constant strain rate can be divided into three stages, which are not similar to metal stress-strain curves; different tensile load velocities induce difference of single silicon crack formation speed; the layered stress results in crack formation in single crystal silicon. It is concluded that the crack growth and propagation is more sensitive to strain rate, tensile load velocity, stress distribution in single crystal silicon.

  15. High-Purity Hybrid Organolead Halide Perovskite Nanoparticles Obtained by Pulsed-Laser Irradiation in Liquid

    KAUST Repository

    Amendola, Vincenzo

    2016-11-17

    Nanoparticles of hybrid organic-inorganic perovskites have attracted a great deal of attention due to their variety of optoelectronic properties, their low cost, and their easier integration into devices with complex geometry, compared with microcrystalline, thin-film, or bulk metal halides. Here we present a novel one-step synthesis of organolead bromide perovskite nanocrystals based on pulsed-laser irradiation in a liquid environment (PLIL). Starting from a bulk CHNHPbBr crystal, our PLIL procedure does not involve the use of high-boiling-point polar solvents or templating agents, and runs at room temperature. The resulting nanoparticles are characterized by high crystallinity and are completely free of any microscopic product or organic coating layer. We also demonstrate the straightforward inclusion of laser-generated perovskite nanocrystals in a polymeric matrix to form a nanocomposite with single- and two-photon luminescence properties.

  16. X-ray emission from stainless steel foils irradiated by femtosecond petawatt laser pulses

    Science.gov (United States)

    Alkhimova, M. A.; Faenov, A. Ya; Pikuz, T. A.; Skobelev, I. Yu; Pikuz, S. A.; Nishiuchi, M.; Sakaki, H.; Pirozhkov, A. S.; Sagisaka, S.; Dover, N. P.; Kondo, Ko; Ogura, K.; Fukuda, Y.; Kiriyama, H.; Esirkepov, T.; Bulanov, S. V.; Andreev, A.; Kando, M.; Zhidkov, A.; Nishitani, K.; Miyahara, T.; Watanabe, Y.; Kodama, R.; Kondo, K.

    2018-01-01

    We report about nonlinear growth of x-ray emission intensity emitted from plasma generated by femtosecond petawatt laser pulses irradiating stainless steel foils. X-ray emission intensity increases as ˜ I 4.5 with laser intensity I on a target. High spectrally resolved x-ray emission from front and rear surfaces of 5 μm thickness stainless steel targets were obtained at the wavelength range 1.7-2.1 Å, for the first time in experiments at femtosecond petawatt laser facility J-KAREN-P. Total intensity of front x-ray spectra three times dominates to rear side spectra for maximum laser intensity I ≈ 3.2×1021 W/cm2. Growth of x-ray emission is mostly determined by contribution of bremsstrahlung radiation that allowed estimating bulk electron plasma temperature for various magnitude of laser intensity on target.

  17. Electron-ion collision rates in atomic clusters irradiated by femtosecond laser pulses

    International Nuclear Information System (INIS)

    Moll, M; Hilse, P; Schlanges, M; Bornath, Th; Krainov, V P

    2010-01-01

    In atomic clusters irradiated by femtosecond laser pulses, plasmas with high density and high temperature are created. The heating is mainly caused by inverse bremsstrahlung, i.e. determined by electron-ion collisions. In the description of the scattering of electrons on noble gas ions in such plasmas, it is important to account for the inner structure of the ions and the screening by the surrounding plasma medium which can be accomplished by using suitable model potentials. In the wide parameter range met in experiments, the Born approximation is not applicable. Instead, the electron-ion collision frequency is calculated on the basis of classical momentum transport cross sections. Results are presented for xenon, krypton and argon ions in different charge states. A comparison of these results to those for the scattering on Coulomb particles with the same charge shows an enhancement of the collision frequency. The Born approximation, however, leads to an overestimation.

  18. New design of the pulsed electro-acoustic upper electrode for space charge measurements during electronic irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Riffaud, J.; Griseri, V.; Berquez, L. [UPS, LAPLACE, Université de Toulouse, 118 Route de Narbonne, Toulouse F-31062, France and CNRS, LAPLACE, Toulouse F-31062 (France)

    2016-07-15

    The behaviour of space charges injected in irradiated dielectrics has been studied for many years for space industry applications. In our case, the pulsed electro-acoustic method is chosen in order to determine the spatial distribution of injected electrons. The feasibility of a ring-shaped electrode which will allow the measurements during irradiation is presented. In this paper, a computer simulation is made in order to determine the parameters to design the electrode and find its position above the sample. The obtained experimental results on polyethylene naphthalate samples realized during electronic irradiation and through relaxation under vacuum will be presented and discussed.

  19. Neutron irradiation facility and its characteristics

    International Nuclear Information System (INIS)

    Oyama, Yukio; Noda, Kenji

    1995-01-01

    A neutron irradiation facility utilizing spallation reactions with high energy protons is conceived as one of the facilities in 'Proton Engineering center (PEC)' proposed at JAERI. Characteristics of neutron irradiation field of the facility for material irradiation studies are described in terms of material damage parameters, influence of the pulse irradiation, irradiation environments other than neutronics features, etc., comparing with the other sorts of neutron irradiation facilities. Some perspectives for materials irradiation studies using PEC are presented. (author)

  20. Pulse energy evolution for high-resolution Lamb wave inspection

    International Nuclear Information System (INIS)

    Hua, Jiadong; Zeng, Liang; Gao, Fei; Lin, Jing

    2015-01-01

    Generally, tone burst excitation methods are used to reduce the effect of dispersion in Lamb wave inspection. In addition, algorithms for dispersion compensation are required to simplify responses, especially in long-range inspection. However, the resolution is always limited by the time duration of tone burst excitation. A pulse energy evolution method is established to overcome this limitation. In this method, a broadband signal with a long time (e.g. a chirp, white noise signal, or a pseudo-random sequence) is used as excitation to actuate Lamb waves. First of all, pulse compression is employed to estimate system impulse response with a high signal-to-noise ratio. Then, dispersion compensation is applied repeatedly with systemically varied compensation distances, obtaining a series of compensated signals. In these signals, amplitude (or energy) evolution associated with the change of compensation distance is utilized to estimate the actual propagation distance of the interested wave packet. Finally, the defect position is detected by an imaging algorithm. Several experiments are given to validate the proposed method. (paper)

  1. Effects of gamma irradiations on reactive pulsed laser deposited vanadium dioxide thin films

    Science.gov (United States)

    Madiba, I. G.; Émond, N.; Chaker, M.; Thema, F. T.; Tadadjeu, S. I.; Muller, U.; Zolliker, P.; Braun, A.; Kotsedi, L.; Maaza, M.

    2017-07-01

    Vanadium oxide films are considered suitable coatings for various applications such as thermal protective coating of small spacecrafts because of their thermochromic properties. While in outer space, such coating will be exposed to cosmic radiations which include γ-rays. To study the effect of these γ-rays on the coating properties, we have deposited vanadium dioxide (VO2) films on silicon substrates and subjected them to extensive γ-irradiations with typical doses encountered in space missions. The prevalent crystallographic phase after irradiation remains the monoclinic VO2 phase but the films preferential orientation shifts to lower angles due to the presence of disordered regions caused by radiations. Raman spectroscopy measurements also evidences that the VO2 structure is slightly affected by gamma irradiation. Indeed, increasing the gamma rays dose locally alters the crystalline and electronic structures of the films by modifying the V-V inter-dimer distance, which in turns favours the presence of the VO2 metallic phase. From the XPS measurements of V2p and O1s core level spectra, an oxidation of vanadium from V4+ towards V5+ is revealed. The data also reveal a hydroxylation upon irradiation which is corroborated by the vanishing of a low oxidation state peak near the Fermi energy in the valence band. Our observations suggest that gamma radiations induce the formation of Frenkel pairs. Moreover, THz transmission measurements show that the long range structure of VO2 remains intact after irradiation whilst the electrical measurements evidence that the coating resistivity decreases with gamma irradiation and that their transition temperature is slightly reduced for high gamma ray doses. Even though gamma rays are only one of the sources of radiations that are encountered in space environment, these results are very promising with regards to the potential of integration of such VO2 films as a protective coating for spacecrafts.

  2. Energy concentration on S-300 pulsed power generator

    Energy Technology Data Exchange (ETDEWEB)

    Bakshaev, Yu Z; Chernenko, A S; Korolev, V D; Mizhiritskij, V I; Zazhivikhin, V V [Kurchatov Institute, Moscow (Russian Federation)

    1997-12-31

    Energy concentration in fast Z-pinch investigation experiments on an 8-module 10 TW pulsed power S-300 generator (1.3 MV, 45 ns FWHM, 0.15 Ohm) is realized by a 3-d vacuum energy concentrator. The concentrator was constructed on the basis of triplate MITLs connected in parallel at the central unit where the Z-pinch is formed. At some start-up experiments on the 8-module installation version at 700 kV incident wave amplitude on concentrator for a gas puff load current of 4 MA with rise time of about 60 ns was obtained. The efficiency or current transfer from the concentrator input to the load for both a gas liner and a short-circuited case was practically the same. (author). 4 figs., 4 refs.

  3. Effects of ablation energy and post-irradiation on the structure and properties of titanium dioxide nanomaterials

    Energy Technology Data Exchange (ETDEWEB)

    Guillén, G. García [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica, San Nicolás de los Garza, Nuevo León 66455, México (Mexico); Shaji, S., E-mail: sshajis@yahoo.com [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica, San Nicolás de los Garza, Nuevo León 66455, México (Mexico); Universidad Autónoma de Nuevo León-CIIDIT, Apodaca, Nuevo León, México (Mexico); Palma, M. I. Mendivil [Centro de Investigación en Materiales Avanzados (CIMAV), Unidad Monterrey, PIIT, Apodaca, Nuevo León, México (Mexico); Avellaneda, D.; Castillo, G.A.; Roy, T.K. Das [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica, San Nicolás de los Garza, Nuevo León 66455, México (Mexico); and others

    2017-05-31

    Highlights: • Highlights • TiO{sub 2} nanomaterials were prepared by PLALM. • Characterized these nanomaterials using TEM, XPS, XRD, optical and luminescence measurements. • Morphology of these nanomaterials were dependent on ablation wavelength, fluence and post-irradiation time. • Laser post irradiation modified the size, morphology and structure of these TiO{sub 2} nanomaterials. - Abstract: Nanomaterials of titanium oxide were prepared by pulsed laser ablation of a titanium metal target in distilled water. The ablation was performed at different laser energy (fluence) using a nanosecond pulsed Nd:YAG laser output of 1064 and 532 nm. A post-irradiation of titanium oxide nanocolloids obtained by ablation using 532 nm was carried out to explore its effects on the structure and properties. Analysis of morphology, crystalline phase, elemental composition, chemical state, optical and luminescent properties were performed using Transmission Electron Microscopy (TEM), X-Ray Diffraction (XRD), X-Ray Photoelectron Spectroscopy (XPS), UV–-vis absorption spectroscopy and room temperature photoluminescence spectroscopy. It was found that titanium oxide nanomaterial morphologies and optical properties were determined by ablation wavelength and fluence. Further, nanocolloids prepared by 532 nm ablation showed a crystalline phase change by laser post-irradiation. The results showed that pulsed laser ablation in liquid as well as post-irradiation were effective in modifying the final structure and properties of titanium oxide nanocolloids.

  4. Effects of ablation energy and post-irradiation on the structure and properties of titanium dioxide nanomaterials

    International Nuclear Information System (INIS)

    Guillén, G. García; Shaji, S.; Palma, M. I. Mendivil; Avellaneda, D.; Castillo, G.A.; Roy, T.K. Das

    2017-01-01

    Highlights: • Highlights • TiO_2 nanomaterials were prepared by PLALM. • Characterized these nanomaterials using TEM, XPS, XRD, optical and luminescence measurements. • Morphology of these nanomaterials were dependent on ablation wavelength, fluence and post-irradiation time. • Laser post irradiation modified the size, morphology and structure of these TiO_2 nanomaterials. - Abstract: Nanomaterials of titanium oxide were prepared by pulsed laser ablation of a titanium metal target in distilled water. The ablation was performed at different laser energy (fluence) using a nanosecond pulsed Nd:YAG laser output of 1064 and 532 nm. A post-irradiation of titanium oxide nanocolloids obtained by ablation using 532 nm was carried out to explore its effects on the structure and properties. Analysis of morphology, crystalline phase, elemental composition, chemical state, optical and luminescent properties were performed using Transmission Electron Microscopy (TEM), X-Ray Diffraction (XRD), X-Ray Photoelectron Spectroscopy (XPS), UV–-vis absorption spectroscopy and room temperature photoluminescence spectroscopy. It was found that titanium oxide nanomaterial morphologies and optical properties were determined by ablation wavelength and fluence. Further, nanocolloids prepared by 532 nm ablation showed a crystalline phase change by laser post-irradiation. The results showed that pulsed laser ablation in liquid as well as post-irradiation were effective in modifying the final structure and properties of titanium oxide nanocolloids.

  5. 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)

  6. Application of pulsed multi-ion irradiations in radiation damage research: A stochastic cluster dynamics simulation study

    Science.gov (United States)

    Hoang, Tuan L.; Nazarov, Roman; Kang, Changwoo; Fan, Jiangyuan

    2018-07-01

    Under the multi-ion irradiation conditions present in accelerated material-testing facilities or fission/fusion nuclear reactors, the combined effects of atomic displacements with radiation products may induce complex synergies in the structural materials. However, limited access to multi-ion irradiation facilities and the lack of computational models capable of simulating the evolution of complex defects and their synergies make it difficult to understand the actual physical processes taking place in the materials under these extreme conditions. In this paper, we propose the application of pulsed single/dual-beam irradiation as replacements for the expensive steady triple-beam irradiation to study radiation damages in materials under multi-ion irradiation.

  7. Practical aspects of irradiance and energy in UV curing

    International Nuclear Information System (INIS)

    Stowe, R.W.

    1999-01-01

    The physical properties of UV-cured materials are substantially affected by the lamp systems used to cure them. The development of the intended properties, whether a varnish, an ink, or an adhesive, can depend on how well these lamp factors are designed and managed. The four key factors of UV exposure are: UV irradiance (or intensity), spectral distribution (wavelengths) of UV, effective energy (time-integrated UV irradiance), and infrared radiation. Inks and varnishes will exhibit very different response to peak irradiance or energy, as well as to different UV spectra. The ability to identify the various lamp characteristics and match them to the optical properties of the curable materials, widens the range in which UV curing is a faster, more efficient production process. This paper explores the reasons for clearly identifying these factors for process optimization

  8. Challenges in validating radiation sterilization with low energy electron irradiation

    International Nuclear Information System (INIS)

    Miller, A.; Helt-Hansen, J.

    2011-01-01

    Complete text of publication follows. Low energy electron irradiation (80-300 keV) is used increasingly for sterilization or decontamination in connection with isolators for aseptic filling lines in the pharmaceutical industry. It is not defined how validation for this process shall be carried out. A method can be derived from the medical device standard for radiation sterilization, ISO 11137, because the principles described in this standard can be applied to almost any industrial irradiation process. The validations elements are: Process definition, concerning specification of the dose required for the process and the maximum acceptable dose for the product. Installation qualification, concerning acceptance the irradiation facility. Operational qualification, concerning characterization of the facility. Performance qualification, concerning setting up the process. Process control, concerning routine monitoring. The limited penetration of the low energy electrons leads to problems with respect to executing these validation steps. This paper discusses these problems, and shows with examples how they can be solved.

  9. Dynamic energy spectrum and energy deposition in solid target by intense pulsed ion beams

    Institute of Scientific and Technical Information of China (English)

    Xiao Yu; Xiao-Yun Le; Zheng Liu; Jie Shen; Yu I.Isakova; Hao-Wen Zhong; Jie Zhang; Sha Yan; Gao-Long Zhang; Xiao-Fu Zhang

    2017-01-01

    A method for analyzing the dynamic energy spectrum of intense pulsed ion beam (IPIB) was proposed.Its influence on beam energy deposition in metal target was studied with IPIB produced by two types of magnetically insulated diodes (MID).The emission of IPIB was described with space charge limitation model,and the dynamic energy spectrum was further analyzed with time-of-flight method.IPIBs generated by pulsed accelerators of BIPPAB-450 (active MID) and TEMP-4M (passive MID) were studied.The dynamic energy spectrum was used to deduce the power density distribution of IPIB in the target with Monte Carlo simulation and infrared imaging diagnostics.The effect on the distribution and evolution of thermal field induced by the characteristics of IPIB dynamic energy spectrum was discussed.

  10. The disintegration and vaporization of plastic targets irradiated by high-power laser pulses

    International Nuclear Information System (INIS)

    Greig, J.R.; Pechacek, R.E.

    1977-01-01

    We have studied the disintegration of polyethylene and polystyrene targets irradiated by 100-J 40-nsec Nd/glass laser pulses. At power densities of approximately-less-than10 12 W/cm 2 relatively massive targets (6 x 10 -5 to 5 x 10 -4 cm 3 ) are totally disintegrated to produce finely divided target material and un-ionized vapor. Both the size of the target and the presence or absence of a laser prepulse strongly influence the proportions of finely divided target material and un-ionized vapor, especially within the first few microseconds after peak laser power. This disintegration is always preceded by the emission of a hot fully ionized plasma, but only 1% of the target material is contained in the hot plasma. Typically, (1--3) x 10 19 atoms of un-ionized vapor are released as a slowly expanding (vapprox.10 5 cm/sec) cold dense gas cloud (n/sub o/>10 19 cm -3 ) surrounding the initial target position. This cloud of target material has subsequently been heated by absorption of a 300-J 100-nsec CO 2 laser pulse to produce an approximately fully ionized plasma

  11. Determining the field emitter temperature during laser irradiation in the pulsed laser atom probe

    International Nuclear Information System (INIS)

    Kellogg, G.L.

    1981-01-01

    Three methods are discussed for determining the field emitter temperature during laser irradiation in the recently developed Pulsed Laser Atom Probe. A procedure based on the reduction of the lattice evaporation field with increasing emitter temperature is found to be the most convenient and reliable method between 60 and 500 K. Calibration curves (plots of the evaporation field versus temperature) are presented for dc and pulsed field evaporation of W, Mo, and Rh. These results show directly the important influence of the evaporation rate on the temperature dependence of the evaporation field. The possibility of a temperature calibration based on the ionic charge state distribution of field evaporated lattice atoms is also discussed. The shift in the charge state distributions which occurs when the emitter temperature is increased and the applied field strength is decreased at a constant rate of evaporation is shown to be due to the changing field and not the changing temperature. Nevertheless, the emitter temperature can be deduced from the charge state distribution for a specified evaporation rate. Charge state distributions as a function of field strength and temperature are presented for the same three materials. Finally, a preliminary experiment is reported which shows that the emitter temperature can be determined from field ion microscope observations of single atom surface diffusion over low index crystal planes. This last calibration procedure is shown to be very useful at higher temperatures (>600 K) where the other two methods become unreliable

  12. 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.

  13. 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.

  14. Modeling of finite systems irradiated by intense ultrashort hard X-ray pulses

    Energy Technology Data Exchange (ETDEWEB)

    Jurek, Zoltan [Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron, Notkestrasse 85, D-22607 Hamburg (Germany); Ziaja, Beata [Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron, Notkestrasse 85, D-22607 Hamburg (Germany); Institute of Nuclear Physics, Polish Academy of Sciences, Radzikowskiego 152, 31-342 Krakow (Poland); Santra, Robin [Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron, Notkestrasse 85, D-22607 Hamburg (Germany); Department of Physics, University of Hamburg, Jungiusstrasse 9, 20355 Hamburg (Germany)

    2013-07-01

    Large number of experiments have already been carried out at the existing hard X-Ray Free-Electron Laser facilities (LCLS, SACLA) during the recent years. Their great success generates even higher anticipation for the forthcoming X-ray sources (European XFEL). Single molecule imaging and nanoplasma formation are the challenging projects with XFELs that investigate the interaction of finite, small objects, e.g. single molecules, atomic clusters with intense X-ray radiation. Accurate modelling of the time evolution of such irradiated systems is required in order to understand the current experiments and to inspire new directions of experimental investigation. In this presentation we report on our theoretical molecular-dynamics tool able to follow non-equilibrium dynamics within finite systems irradiated by intense X-ray pulses. We introduce the relevant physical processes, present computational methods used, discuss their limitations and also the specific constraints on calculations imposed by experimental conditions. Finally, we conclude with a few simulation examples.

  15. Pigmented guinea pig skin irradiated with Q-switched ruby laser pulses. Morphologic and histologic findings

    Energy Technology Data Exchange (ETDEWEB)

    Dover, J.S.; Margolis, R.J.; Polla, L.L.; Watanabe, S.; Hruza, G.J.; Parrish, J.A.; Anderson, R.R.

    1989-01-01

    Q-switched ruby laser pulses cause selective damage to cutaneous pigmented cells. Repair of this selective damage has not been well described. Therefore, using epilated pigmented and albino guinea pig skin, we studied the acute injury and tissue repair caused by 40-ns, Q-switched ruby laser pulses. Gross observation and light and electron microscopy were performed. No specific changes were evident in the albino guinea pigs. In pigmented animals, with radiant exposures of 0.4 J/cm2 or greater, white spots confined to the 2.5-mm exposure sites developed immediately and faded over 20 minutes. Delayed depigmentation occurred at seven to ten days, followed by full repigmentation by four to eight weeks. Regrowing hairs in sites irradiated at and above 0.4 J/cm2 remained white for at least four months. Histologically, vacuolation of pigment-laden cells was seen immediately in the epidermis and the follicular epithelium at exposures of 0.3 J/cm2 and greater. Melanosomal disruption was seen immediately by electron microscopy at and above 0.3 J/cm2. Over the next seven days, epidermal necrosis was followed by regeneration of a depigmented epidermis. By four months, melanosomes and melanin pigmentation had returned; however, hair follicles remained depigmented and devoid of melanocytes. This study demonstrates that selective melanosomal disruption caused by Q-switched ruby laser pulses leads to transient cutaneous depigmentation and persistent follicular depigmentation. Potential exists for selective treatment of pigmented epidermal and dermal lesions with this modality.

  16. High dose-rate irradiation of materials with pulsed ion beams at NDCX-II

    Science.gov (United States)

    Seidl, Peter; Treffert, F.; Ji, Q.; Ludewigt, B.; Persaud, A.; Kong, X.; de Leon, S. J.; Dowling, E.; Waldron, W. L.; Schenkel, T.; Barnard, J. J.; Friedman, A.; Grote, D. P.; Stepanov, A.; Gilson, E. P.; Kaganovich, I. D.

    2017-10-01

    Charged particle radiation effects in materials is important for the design of fusion plasma facing components. Also, radiation effects in semiconductor devices are of interest for many applications such as detectors and space electronics. We present results from radiation effects studies with intense pulses of helium ions that impinged on thin samples at the induction linac at Berkeley Lab (Neutralized Drift Compression Experiment-II). Intense bunches of 1.2 MeV He+ ions with peak currents of 2 A, 1-mm beam spot radius and 2-30 ns FWHM duration create controlled high instantaneous dose rates enabling the exploration of collective damage effects. We use in-situ diagnostics to monitor transient effects due to rapid heating and the ionization and damage cascade dynamics. For tin, single pulses deposit sufficient energy in the foil to drive phase transitions. A new Thomson parabola to measures ion energy loss and charge state distributions following transmission of a few micron thick samples. In silicon, ion pulses induce free electron densities of order 1021 cm-3. Supported by the Office of Science of the US DOE under contracts DE-AC0205CH11231, DE-AC52-07NA27344 and DE-AC02-09CH11466 and by the China Scholarship Council.

  17. The affect of erbium hydride on the conversion efficience to accelerated protons from ultra-shsort pulse laser irradiated foils

    Energy Technology Data Exchange (ETDEWEB)

    Offermann, Dustin Theodore [The Ohio State Univ., Columbus, OH (United States)

    2008-01-01

    This thesis work explores, experimentally, the potential gains in the conversion efficiency from ultra-intense laser light to proton beams using erbium hydride coatings. For years, it has been known that contaminants at the rear surface of an ultra-intense laser irradiated thin foil will be accelerated to multi-MeV. Inertial Confinement Fusion fast ignition using proton beams as the igniter source requires of about 1016 protons with an average energy of about 3MeV. This is far more than the 1012 protons available in the contaminant layer. Target designs must include some form of a hydrogen rich coating that can be made thick enough to support the beam requirements of fast ignition. Work with computer simulations of thin foils suggest the atomic mass of the non-hydrogen atoms in the surface layer has a strong affect on the conversion efficiency to protons. For example, the 167amu erbium atoms will take less energy away from the proton beam than a coating using carbon with a mass of 12amu. A pure hydrogen coating would be ideal, but technologically is not feasible at this time. In the experiments performed for my thesis, ErH3 coatings on 5 μm gold foils are compared with typical contaminants which are approximately equivalent to CH1.7. It will be shown that there was a factor of 1.25 ± 0.19 improvement in the conversion efficiency for protons above 3MeV using erbium hydride using the Callisto laser. Callisto is a 10J per pulse, 800nm wavelength laser with a pulse duration of 200fs and can be focused to a peak intensity of about 5 x 1019W/cm2. The total number of protons from either target type was on the order of 1010. Furthermore, the same experiment was performed on the Titan laser, which has a 500fs pulse duration, 150J of energy and can be focused to about 3 x 1020 W/cm2. In this experiment 1012 protons were seen from both erbium hydride and

  18. High energy irradiation of bacterial membrane vesicles

    International Nuclear Information System (INIS)

    De La Rosa, M.A.M.

    1977-01-01

    The interactions of membrane components and two well-defined transport systems in the E. coli ML 308-225 membrane vesicles with 60 Co gamma radiation were investigated. The results presented show that gamma radiation can monitor membrane components and functions of varying radiosensitivities. The possible application of high-energy radiation as a physical probe of membrane structure and functions is indeed promising

  19. Latest version of the Munich pulsed low energy positron system

    International Nuclear Information System (INIS)

    Bauer-Kugelmann, W.; Sperr, P.; Koegel, G.; Triftshaeuser, W.

    2001-01-01

    Further improvements of the Munich pulsed low energy positron system have been performed. A new chopper, configured as a double plate deflection system with an external resonator and a new buncher working like a classical double gap buncher, are implemented. The complete rf-power electronic was redesigned and operates now at an overall master-frequency of 50 MHz for all bunching and chopping components. A new target station with an enlarged Faraday cage is installed. The sample temperature is variable between 30 K and 600 K. Up to ten samples can be stored in a magazine and transferred under vacuum conditions to the measuring position. With a primary source of 30 mCi 22 Na a count rate of up to 4 kHz can be achieved with a peak-to-background ratio of 3000:1. This ratio can be further improved by the use of a Wien filter. A beam diameter of about 2 mm was determined. The total time resolution (pulsing plus detector system) is 250 ps (FWHM). (orig.)

  20. High-energy irradiation in the management of chondrosarcoma

    International Nuclear Information System (INIS)

    Kim, R.Y.; Salter, M.M.; Brascho, D.J.

    1983-01-01

    We present a retrospective analysis of seven patients with chondrosarcoma of the bone treated by high-energy irradiation between 1961 and 1976. Its major role in this series was prevention of local recurrence in cases with inadequate resection. In three of the five cases in which radiation therapy was adjuvant rather than primary treatment, long-term local control was obtained in a dose of 5,000 to 6,500 rads in five to six weeks. Although primary treatment of chondrosarcoma is surgical, high-dose radiation therapy is indicated when surgical resection is not possible. Chondrosarcoma can respond to high doses of irradiation even though the response is slow

  1. Absorption of short-pulse electromagnetic energy by a resistively loaded straight wire

    International Nuclear Information System (INIS)

    Miller, E.K.; Deadrick, F.J.; Landt, J.A.

    1975-01-01

    Absorption of short-pulse electromagnetic energy by a resistively loaded straight wire is examined. Energy collected by the wire, load energy, peak load currents, and peak load voltages are found for a wide range of parameters, with particular emphasis on nuclear electromagnetic pulse (EMP) phenomena. A series of time-sequenced plots is used to illustrate pulse propagation on wires when loads and wire ends are encountered

  2. CENTER FOR PULSED POWER DRIVEN HIGH ENERGY DENSITY PLASMA STUDIES

    Energy Technology Data Exchange (ETDEWEB)

    Professor Bruce R. Kusse; Professor David A. Hammer

    2007-04-18

    This annual report summarizes the activities of the Cornell Center for Pulsed-Power-Driven High-Energy-Density Plasma Studies, for the 12-month period October 1, 2005-September 30, 2006. This period corresponds to the first year of the two-year extension (awarded in October, 2005) to the original 3-year NNSA/DOE Cooperative Agreement with Cornell, DE-FC03-02NA00057. As such, the period covered in this report also corresponds to the fourth year of the (now) 5-year term of the Cooperative Agreement. The participants, in addition to Cornell University, include Imperial College, London (IC), the University of Nevada, Reno (UNR), the University of Rochester (UR), the Weizmann Institute of Science (WSI), and the P.N. Lebedev Physical Institute (LPI), Moscow. A listing of all faculty, technical staff and students, both graduate and undergraduate, who participated in Center research activities during the year in question is given in Appendix A.

  3. Bifurcation-free design method of pulse energy converter controllers

    International Nuclear Information System (INIS)

    Kolokolov, Yury; Ustinov, Pavel; Essounbouli, Najib; Hamzaoui, Abdelaziz

    2009-01-01

    In this paper, a design method of pulse energy converter (PEC) controllers is proposed. This method develops a classical frequency domain design, based on the small signal modeling, by means of an addition of a nonlinear dynamics analysis stage. The main idea of the proposed method consists in fact that the PEC controller, designed with an application of the small signal modeling, is tuned after with taking into the consideration an essentially nonlinear nature of the PEC that makes it possible to avoid bifurcation phenomena in the PEC dynamics at the design stage (bifurcation-free design). Also application of the proposed method allows an improvement of the designed controller performance. The application of this bifurcation-free design method is demonstrated on an example of the controller design of direct current-direct current (DC-DC) buck converter with an input electromagnetic interference filter.

  4. Low energy ion implantation and high energy heavy ion irradiation in C60 films

    International Nuclear Information System (INIS)

    Narayanan, K.L.; Yamaguchi, M.; Dharmarasu, N.; Kojima, N.; Kanjilal, D.

    2001-01-01

    C 60 films have been bombarded with low energy boron ions and high energy swift heavy ions (SHI) of silver and oxygen at different doses. Raman scattering and Fourier transform infrared (FTIR) studies were carried out on the virgin and irradiated films and the results are in good agreement with each other. The films subject to low energy boron ion implantation showed destruction of the bukky balls whereas the films subject to high energy ion irradiation did not show appreciable effects on their structure. These results indicate that C 60 films are more prone to defects by elastic collision and subsequent implantation at lower energy. Irradiation at higher energy was less effective in creating appreciable defects through electronic excitation by inelastic collisions at similar energy density

  5. Energy-correction photon counting pixel for photon energy extraction under pulse pile-up

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Daehee; Park, Kyungjin; Lim, Kyung Taek; Cho, Gyuseong, E-mail: gscho@kaist.ac.kr

    2017-06-01

    A photon counting detector (PCD) has been proposed as an alternative solution to an energy-integrating detector (EID) in medical imaging field due to its high resolution, high efficiency, and low noise. The PCD has expanded to variety of fields such as spectral CT, k-edge imaging, and material decomposition owing to its capability to count and measure the number and the energy of an incident photon, respectively. Nonetheless, pulse pile-up, which is a superimposition of pulses at the output of a charge sensitive amplifier (CSA) in each PC pixel, occurs frequently as the X-ray flux increases due to the finite pulse processing time (PPT) in CSAs. Pulse pile-up induces not only a count loss but also distortion in the measured X-ray spectrum from each PC pixel and thus it is a main constraint on the use of PCDs in high flux X-ray applications. To minimize these effects, an energy-correction PC (ECPC) pixel is proposed to resolve pulse pile-up without cutting off the PPT by adding an energy correction logic (ECL) via a cross detection method (CDM). The ECPC pixel with a size of 200×200 µm{sup 2} was fabricated by using a 6-metal 1-poly 0.18 µm CMOS process with a static power consumption of 7.2 μW/pixel. The maximum count rate of the ECPC pixel was extended by approximately three times higher than that of a conventional PC pixel with a PPT of 500 nsec. The X-ray spectrum of 90 kVp, filtered by 3 mm Al filter, was measured as the X-ray current was increased using the CdTe and the ECPC pixel. As a result, the ECPC pixel dramatically reduced the energy spectrum distortion at 2 Mphotons/pixel/s when compared to that of the ERCP pixel with the same 500 nsec PPT.

  6. K-α emission form medium and high-Z materials irradiated by femtosecond laser pulses

    International Nuclear Information System (INIS)

    Limpouch, J.; Klimo, O.; Zhavoronkov, N.; Andreev, A.A.

    2006-01-01

    Complete test of publication follows. Fast electrons are created at the target surface during the interaction of high intensity ultra short laser pulses with solids. Fast electrons penetrate deep into the target where they generate K-α and Bremsstrahlung radiation. Generated high brightness K-α pulses offer the prospect of creating a cheap and compact X-ray source, posing a promising alternative to synchrotron radiation, e.g. in medical application and in material science. With an increase in laser intensity, efficient X-ray emission in the multi-keV range with pulse duration shorter than few picoseconds is expected. This short incoherent but monochromatic X-ray emission synchronized with laser pulses may be used for time-resolved measurements. Acceleration of fast electrons, their transport and K-α photon generation and emission from the target surface in both forward and backward directions are studied here numerically. The results are compared to recent experiments studying K-α emission from the front and rear surface of copper foil targets of various thicknesses and for various parameters of the laser plasma interaction. One-dimensional PIC simulations coupled with 3D time-resolved Monte Carlo simulations show that account of ionization processes and of density profile formed by laser ASE emission is essential for reliable explanation of experimental data. While sub-relativistic intensities are optimum for laser energy transformation into K-α emission for medium-Z targets, relativistic laser intensities have to be used for hard X-ray generation in high-Z materials. The cross-section for K-α shell ionization of high-Z elements by electrons increases or remains approximately constant within a factor of two at relativistic electron energies up to electron energies in the 100-MeV range. Moreover, the splitting ratio of K-α photon emission to Auger electron emission is favorable for high-Z materials, and thus efficient K-α emission is possible. In our

  7. Investigation on the Effect of Pulsed Energy on Strength of Fillet Lap Laser Welded AZ31B Magnesium Alloys

    Science.gov (United States)

    Salleh, M. N. M.; Ishak, M.; Aiman, M. H.; Idris, S. R. A.; Romlay, F. R. M.

    2017-09-01

    AZ31B magnesium alloy have been hugely applied in the aerospace, automotive, and electronic industries. However, welding thin sheet AZ31B was challenging due to its properties which is easily to evaporated especially using conventional fusion welding method such as metal inert gas (MIG). Laser could be applied to weld this metal since it produces lower heat input. The application of fiber laser welding has been widely since this type of laser could produce better welding product especially in the automotive sectors. Low power fiber laser was used to weld this non-ferrous metal where pulse wave (PW) mode was used. Double fillet lap joint was applied to weld as thin as 0.6 mm thick of AZ31B and the effect of pulsed energy on the strength was studied. Bond width, throat length, and penetration depth also was studied related to the pulsed energy which effecting the joint. Higher pulsed energy contributes to the higher fracture load with angle of irradiation lower than 3 °

  8. The application analysis of high energy electron accelerator in food irradiation processing

    International Nuclear Information System (INIS)

    Deng Wenmin; Chen Hao; Feng Lei; Zhang Yaqun; Chen Xun; Li Wenjun; Xiang Chengfen; Pei Ying; Wang Zhidong

    2012-01-01

    Irradiation technology of high energy electron accelerator has been highly concerned in food processing industry with its fast development, especially in the field of food irradiation processing. In this paper, equipment and research situation of high energy electron accelerator were collected, meanwhile, the similarities and differences between high energy electron beam and 60 Co γ-rays were discussed. In order to provide more references of high energy electron beam irradiation, the usages of high energy electron in food irradiation processing was prospected. These information would promote the development of domestic food irradiation industry and give a useful message to irradiation enterprises and researchers. (authors)

  9. Surface modifications on toughened, fine-grained, recrystallized tungsten with repetitive ELM-like pulsed plasma irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Kikuchi, Y., E-mail: ykikuchi@eng.u-hyogo.ac.jp [Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji, 671-2280 Hyogo (Japan); Sakuma, I.; Kitagawa, Y.; Asai, Y.; Onishi, K.; Fukumoto, N.; Nagata, M. [Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji, 671-2280 Hyogo (Japan); Ueda, Y. [Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Kurishita, H. [Institute for Materials Research, Tohoku University, Ibaraki 311-1313 (Japan)

    2015-08-15

    Surface modifications of toughened, fine-grained, recrystallized tungsten (TFGR W) materials with 1.1 wt.% TiC and 3.3 wt.% TaC dispersoids due to repetitive ELM-like pulsed (∼0.15 ms) helium plasma irradiation have been investigated by using a magnetized coaxial plasma gun. No surface cracking at the center part of the TFGR W samples exposed to 20 plasma pulses of ∼0.3 MJ m{sup −2} was observed. The suppression of surface crack formation due to the increase of the grain boundary strength by addition of TiC and TaC dispersoids was confirmed in comparison with a pure W material. On the other hand, surface cracks and small pits appeared at the edge part of the TFGR W sample after the pulsed plasma irradiation. Erosion of the TiC and TaC dispersoids due to the pulsed plasma irradiation could cause the small pits on the surface, resulting in the surface crack formation.

  10. Surface modifications on toughened, fine-grained, recrystallized tungsten with repetitive ELM-like pulsed plasma irradiation

    Science.gov (United States)

    Kikuchi, Y.; Sakuma, I.; Kitagawa, Y.; Asai, Y.; Onishi, K.; Fukumoto, N.; Nagata, M.; Ueda, Y.; Kurishita, H.

    2015-08-01

    Surface modifications of toughened, fine-grained, recrystallized tungsten (TFGR W) materials with 1.1 wt.% TiC and 3.3 wt.% TaC dispersoids due to repetitive ELM-like pulsed (∼0.15 ms) helium plasma irradiation have been investigated by using a magnetized coaxial plasma gun. No surface cracking at the center part of the TFGR W samples exposed to 20 plasma pulses of ∼0.3 MJ m-2 was observed. The suppression of surface crack formation due to the increase of the grain boundary strength by addition of TiC and TaC dispersoids was confirmed in comparison with a pure W material. On the other hand, surface cracks and small pits appeared at the edge part of the TFGR W sample after the pulsed plasma irradiation. Erosion of the TiC and TaC dispersoids due to the pulsed plasma irradiation could cause the small pits on the surface, resulting in the surface crack formation.

  11. Whole tumor antigen vaccination using dendritic cells: Comparison of RNA electroporation and pulsing with UV-irradiated tumor cells

    Directory of Open Access Journals (Sweden)

    Benencia Fabian

    2008-04-01

    Full Text Available Abstract Because of the lack of full characterization of tumor associated antigens for solid tumors, whole antigen use is a convenient approach to tumor vaccination. Tumor RNA and apoptotic tumor cells have been used as a source of whole tumor antigen to prepare dendritic cell (DC based tumor vaccines, but their efficacy has not been directly compared. Here we compare directly RNA electroporation and pulsing of DCs with whole tumor cells killed by ultraviolet (UV B radiation using a convenient tumor model expressing human papilloma virus (HPV E6 and E7 oncogenes. Although both approaches led to DCs presenting tumor antigen, electroporation with tumor cell total RNA induced a significantly higher frequency of tumor-reactive IFN-gamma secreting T cells, and E7-specific CD8+ lymphocytes compared to pulsing with UV-irradiated tumor cells. DCs electroporated with tumor cell RNA induced a larger tumor infiltration by T cells and produced a significantly stronger delay in tumor growth compared to DCs pulsed with UV-irradiated tumor cells. We conclude that electroporation with whole tumor cell RNA and pulsing with UV-irradiated tumor cells are both effective in eliciting antitumor immune response, but RNA electroporation results in more potent tumor vaccination under the examined experimental conditions.

  12. Role of thermal stresses on pulsed laser irradiation of thin films under conditions of microbump formation and nonvaporization forward transfer

    Science.gov (United States)

    Meshcheryakov, Yuri P.; Shugaev, Maxim V.; Mattle, Thomas; Lippert, Thomas; Bulgakova, Nadezhda M.

    2013-11-01

    This paper presents a theoretical analysis of the processes in thin solid films irradiated by short and ultrashort laser pulses in the regimes of film structuring and laser-induced forward transfer. The regimes are considered at which vaporization of the film materials is insignificant and film dynamics is governed mainly by mechanical processes. Thermoelastoplastic modeling has been performed for a model film in one- and two-dimensional geometries. A method has been proposed to estimate the height of microbumps produced by nanosecond laser irradiation of solid films. Contrary to femtosecond laser pulses, in nanosecond pulse regimes, stress waves across the film are weak and cannot induce film damage. The main role in laser-induced dynamics of irradiated films is played by radial thermal stresses which lead to the formation of a bending wave propagating along the film and drawing the film matter to the center of the irradiation spot. The bending wave dynamics depends on the hardness of the substrate underlying the film. The causes of the receiver substrate damage sometimes observed upon laser-induced forward transfer in the scheme of the direct contact between the film and the receiver are discussed.

  13. Enhancement of metal-nanoparticle precipitation by co-irradiation of high-energy heavy ions and laser in silica glass

    International Nuclear Information System (INIS)

    Okubo, N.; Umeda, N.; Takeda, Y.; Kishimoto, N.

    2003-01-01

    Simultaneous laser irradiation under ion irradiation is conducted to control nanoparticle precipitation in amorphous (a-)SiO 2 . Copper ions of 3 MeV and photons of 532 nm by Nd:YAG laser are irradiated to substrates of a-SiO 2 . The ion dose rate and total dose are set at 2-10 μA/cm 2 and 3.0 x 10 16 -3.0 x 10 17 ions/cm 2 , respectively, and the laser power density is 0.05-0.2 J/cm 2 pulse at 10 Hz. The laser is simultaneously irradiated with ions in the co-irradiation mode, and the result is compared to that in the sequential and ion-only irradiation. Cross-sectional TEM of the irradiated specimens is conducted after measuring optical absorption spectra. In the case of co-irradiation of intense laser power and high dose (0.2 J/cm 2 pulse and 3.0 x 10 17 ions/cm 2 ), Cu nanoparticles precipitate much more extensively than in the sequential irradiation, increasing both the particle diameter and the total Cu atoms in the nanoparticles. The optical absorption spectra show a surface plasmon peak of the nanoparticles. The precipitation enhancement in the co-irradiation mode suggests that the electronic energy is absorbed by the dynamic electronic states and promotes the Cu precipitation via enhancing the atomic migration

  14. Enhanced light scattering in Si nanostructures produced by pulsed laser irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Sberna, P. M.; Scapellato, G. G.; Boninelli, S.; Miritello, M.; Crupi, I.; Bruno, E.; Privitera, V.; Simone, F.; Mirabella, S. [MATIS IMM-CNR and Dipartimento di Fisica e Astronomia, Università di Catania, via S. Sofia 64, 95123 Catania (Italy); Piluso, N. [IMM-CNR, VIII strada 5, 95121 Catania (Italy)

    2013-11-25

    An innovative method for Si nanostructures (NS) fabrication is proposed, through nanosecond laser irradiation (λ = 532 nm) of thin Si film (120 nm) on quartz. Varying the laser energy fluences (425–1130 mJ/cm{sup 2}) distinct morphologies of Si NS appear, going from interconnected structures to isolated clusters. Film breaking occurs through a laser-induced dewetting process. Raman scattering is enhanced in all the obtained Si NS, with the largest enhancement in interconnected Si structures, pointing out an increased trapping of light due to multiple scattering. The reported method is fast, scalable and cheap, and can be applied for light management in photovoltaics.

  15. Ceramic to metal joining by using 1064 nm pulsed and CW laser energy source

    International Nuclear Information System (INIS)

    Lee, Young Min; Kim, Soo Won; Choi, Hae Woon; Kim, Joo Han

    2013-01-01

    A novel joining method for ceramic and metallic layers is proposed using laser drilling and surface tension driven liquid metal filling. A high intensity laser beam irradiated a 500 µm thick ceramic filter, and the irradiated laser drilled the ceramic layer. The pulsed or CW laser transmitted through the ceramic layer irradiated the bottom metallic layer; the molten metallic layer then filled the drilled ceramic holes by the capillary force between the liquid metal and ceramic layer. As process variables, average laser power, pulse duration, and the number of pulses were used. The scattering optical properties were also studied for both green and red lasers. There was no significant difference between the colors and the estimated extinction coefficients were -26.94 1/mm and -28.42 1/mm for the green and red lasers, respectively.

  16. Surface composition, microstructure and corrosion resistance of AZ31 magnesium alloy irradiated by high-intensity pulsed ion beam

    International Nuclear Information System (INIS)

    Li, P.; Lei, M.K.; Zhu, X.P.

    2011-01-01

    High-intensity pulsed ion beam (HIPIB) irradiation of AZ31 magnesium alloy is performed and electrochemical corrosion experiment of irradiated samples is carried out by using potentiodynamic polarization technology in order to explore the effect of HIPIB irradiation on corrosion resistance of magnesium alloy. The surface composition, cross-sectional morphology and microstructure are characterized by using electron probe microanalyzer, optical microscope and transmission electron microscope, respectively. The results indicated that HIPIB irradiation leads to a significant improvement in corrosion resistance of magnesium alloy, in terms of the considerable increase in both corrosion potential and pitting breakdown potential. The microstructural refinement and surface purification induced by HIPIB irradiation are responsible for the improved corrosion resistance. - Research Highlights: → A modified layer about 30 μm thick is obtained by HIPIB irradiation. → Selective ablation of element/impurity phase having lower melting point is observed. → More importantly, microstructural refinement occurred on the irradiated surface. → The modified layer exhibited a significantly improved corrosion resistance. → Improved corrosion resistance is ascribed to the combined effect induced by HIPIB.

  17. In situ investigation of formation of self-assembled nanodomain structure in lithium niobate after pulse laser irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Shur, V. Ya.; Kuznetsov, D. K.; Mingaliev, E. A.; Yakunina, E. M.; Lobov, A. I.; Ievlev, A. V. [Ferroelectric Laboratory, Institute of Physics and Applied Mathematics, Ural State University, Lenin Ave. 51, Ekaterinburg 620083 (Russian Federation)

    2011-08-22

    The evolution of the self-assembled quasi-regular micro- and nanodomain structures after pulse infrared laser irradiation was studied by in situ optical observation. The average periods of the structures are much less than the sizes of the laser spots. The polarization reversal occurs through covering of the whole irradiated area by the nets of the spatially separated nanodomain chains and microdomain rays--''hatching effect.'' The main stages of the anisotropic nanodomain kinetics: nucleation, growth, and branching, have been singled out. The observed abnormal domain kinetics was attributed to the action of the pyroelectric field arising during cooling after laser heating.

  18. Demonstration and evaluation of the pulsed ultraviolet-irradiation gas-treatment system, Savannah River Site

    International Nuclear Information System (INIS)

    Schneider, J.; Wilkey, M.; Peters, R.; Tomczyk, N.; Friedlund, J.; Farber, P.

    1994-10-01

    Argonne National Laboratory was asked to demonstrate and evaluate a pulsed ultraviolet-irradiation system developed by Purus, Inc., at the Volatile Organic Compounds Non-Arid Integrated Demonstration at the Savannah River Site near aiken, South Carolina. The Purus system consists of four reactor chambers, each containing a xenon flash lamp. During the two weeks of testing, samples were taken and analyzed from the inlet and outlet sides of the Purus system. The contaminants of concern on the inlet were tetrachloroethylene (PCE), trichloroethylene (TCE), and 1,1,1-trichloroethane (TCA); the contaminants of concern on the outlet were PCE, TCE, TCA, carbon tetrachloride (CT), and chloroform. The evaluation of the Purus system included an examination of the reduction of both TCE and PCE and a search for any change in the concentrations. (Operating conditions included flow rates, ranging from 25 to 100 standard cubic feet per minute; inlet concentration of PCE, ranging from 360 to 10,700 parts per million volume; and flash lamp rates, ranging from 1 to 30 hertz.) The Purus system was quite efficient at reducing the concentrations of both PCE and TCE. The potential by-products, TCA, CT, and chloroform, showed no significant increases throughout the range of the various operating parameters. Overall, the Purus system appears to be a cost-efficient means of reducing the concentrations of PCE and TCE, while the removal of the initial photo-oxidation products and TCA is slower and needs further evaluation

  19. Mimicking lizard-like surface structures upon ultrashort laser pulse irradiation of inorganic materials

    Science.gov (United States)

    Hermens, U.; Kirner, S. V.; Emonts, C.; Comanns, P.; Skoulas, E.; Mimidis, A.; Mescheder, H.; Winands, K.; Krüger, J.; Stratakis, E.; Bonse, J.

    2017-10-01

    Inorganic materials, such as steel, were functionalized by ultrashort laser pulse irradiation (fs- to ps-range) to modify the surface's wetting behavior. The laser processing was performed by scanning the laser beam across the surface of initially polished flat sample material. A systematic experimental study of the laser processing parameters (peak fluence, scan velocity, line overlap) allowed the identification of different regimes associated with characteristic surface morphologies (laser-induced periodic surface structures, grooves, spikes, etc.). Analyses of the surface using optical as well as scanning electron microscopy revealed morphologies providing the optimum similarity to the natural skin of lizards. For mimicking skin structures of moisture-harvesting lizards towards an optimization of the surface wetting behavior, additionally a two-step laser processing strategy was established for realizing hierarchical microstructures. In this approach, micrometer-scaled capillaries (step 1) were superimposed by a laser-generated regular array of small dimples (step 2). Optical focus variation imaging measurements finally disclosed the three dimensional topography of the laser processed surfaces derived from lizard skin structures. The functionality of these surfaces was analyzed in view of wetting properties.

  20. Nanostructured Solar Irradiation Control Materials for Solar Energy Conversion

    Science.gov (United States)

    Kang, Jinho; Marshall, I. A.; Torrico, M. N.; Taylor, C. R.; Ely, Jeffry; Henderson, Angel Z.; Kim, J.-W.; Sauti, G.; Gibbons, L. J.; Park, C.; hide

    2012-01-01

    Tailoring the solar absorptivity (alpha(sub s)) and thermal emissivity (epsilon(sub T)) of materials constitutes an innovative approach to solar energy control and energy conversion. Numerous ceramic and metallic materials are currently available for solar absorbance/thermal emittance control. However, conventional metal oxides and dielectric/metal/dielectric multi-coatings have limited utility due to residual shear stresses resulting from the different coefficient of thermal expansion of the layered materials. This research presents an alternate approach based on nanoparticle-filled polymers to afford mechanically durable solar-absorptive and thermally-emissive polymer nanocomposites. The alpha(sub s) and epsilon(sub T) were measured with various nano inclusions, such as carbon nanophase particles (CNPs), at different concentrations. Research has shown that adding only 5 wt% CNPs increased the alpha(sub s) and epsilon(sub T) by a factor of about 47 and 2, respectively, compared to the pristine polymer. The effect of solar irradiation control of the nanocomposite on solar energy conversion was studied. The solar irradiation control coatings increased the power generation of solar thermoelectric cells by more than 380% compared to that of a control power cell without solar irradiation control coatings.

  1. Time-resolved SFG study of formate on a Ni( 1 1 1 ) surface under irradiation of picosecond laser pulses

    Science.gov (United States)

    Noguchi, H.; Okada, T.; Onda, K.; Kano, S. S.; Wada, A.; Domen, K.

    2003-03-01

    Time-resolved sum-frequency generation spectroscopy was carried out on a deuterated formate (DCOO) adsorbed on Ni(1 1 1) surface to investigate the surface reaction dynamics under instantaneous surface temperature jump induced by the irradiation by picosecond laser pulses. The irradiation of pump pulse (800 nm) caused the rapid intensity decrease of both CD and OCO stretching modes of bridged formate on Ni(1 1 1). Different temporal behaviors of intensity recovery between these two vibrational modes were observed, i.e., CD stretching mode recovered faster than OCO. This is the first result to show that the dynamics of adsorbates on metals strongly depends on the observed vibrational mode. From the results of temperature and pump fluence dependence, we concluded that the observed intensity change was not due to the decomposition or desorption, but was induced by a non-thermal process.

  2. Reduction of upper shelf energy of highly irradiated RPV steels

    Energy Technology Data Exchange (ETDEWEB)

    Otaka, M.; Osaki, T. [Japan Nuclear Energy Safety Organization (Japan)

    2004-07-01

    It is well known that as the embrittlement due to neutron irradiation of reactor pressure vessel (RPV) steels, there is the tendency of the decrease in Charpy absorbed energy at upper shelf region (USE), in addition to the shift of ductile-brittle transition temperature. Concerning to the regulation of the upper shelf region, no method is provided to evaluate integrity for RPV steels with USE of less than 68J in Japanese codes. Under the circumstance, the reduction tendency of USE using simulated Japanese RPV steels, irradiated by fast neutron up to 1 x 10{sup 24} n/m{sup 2}, E>1 MeV in the OECD Halden test reactor, was investigated to establish the basis of the USE prediction after 60 year plant operation for the integrity assessment of the RPVs. This paper describes the results of an atom probe tomography characterization of irradiated steels. A new form of USE prediction equation was developed based on the atom probe tomography characterization and the Charpy impact test results of the irradiated steels. And, the USE prediction equations have been determined through the regression analysis of the test reactor data combined with Japanese surveillance test data. (orig.)

  3. Comparison of radiosensitization by 41 deg. C hyperthermia during low dose rate irradiation and during pulsed simulated low dose rate irradiation in human glioma cells

    International Nuclear Information System (INIS)

    Raaphorst, G. Peter; Ng, Cheng E.; Shahine, Bilal

    1999-01-01

    Purpose: Long duration mild hyperthermia has been shown to be an effective radiosensitizer when given concurrently with low dose rate irradiation. Pulsed simulated low dose rate (PSLDR) is now being used clinically, and we have set out to determine whether concurrent mild hyperthermia can be an effective radiosensitizer for the PSLDR protocol. Materials and Methods: Human glioma cells (U-87MG) were grown to plateau phase and treated in plateau phase in order to minimize cell cycle redistribution during protracted treatments. Low dose rate (LDR) irradiation and 41 deg. C hyperthermia were delivered by having a radium irradiator inside a temperature-controlled incubator. PSLDR was given using a 150 kVp X-ray unit and maintaining the cells at 41 deg. C between irradiations. The duration of irradiation and concurrent heating depended on total dose and extended up to 48 h. Results: When 41 deg. C hyperthermia was given currently with LDR or PSLDR, the thermal enhancement ratios (TER) were about the same if the average dose rate for PSLDR was the same as for LDR. At higher average dose rates for PSLDR the TERs became less. Conclusions: Our data show that concurrent mild hyperthermia can be an effective sensitizer for PSLDR. This sensitization can be as effective as for LDR if the same average dose rate is used and the TER increases with decreasing dose rate. Thus mild hyperthermia combined with PSLDR may be an effective clinical protocol

  4. Energy and dose characteristics of ion bombardment during pulsed laser deposition of thin films under pulsed electric field

    International Nuclear Information System (INIS)

    Fominski, V.Yu.; Nevolin, V.N.; Smurov, I.

    2004-01-01

    Experiments on pulsed laser deposition of Fe films on Si substrates were performed with the aim to analyze the role of factors determining the formation of an energy spectrum and a dose of ions bombarding the film in strong pulsed electric fields. The amplitude of the high-voltage pulse (-40 kV) applied to the substrate and the laser fluence at the Fe target were fixed during the deposition. Owing to the high laser fluence (8 J/cm 2 ) at a relatively low power (20 mJ), the ionization of the laser plume was high, but the Fe vapor pressure near the substrate was low enough to avoid arcing. Electric signals from a target exposed to laser radiation were measured under different conditions (at different delay times) of application of electric pulses. The Si(100) substrates were analyzed using Rutherford ion backscattering/channeling spectrometry. The ion implantation dose occurred to be the highest if the high-voltage pulse was applied at a moment of time when the ion component of the plume approached the substrate. In this case, the implanted ions had the highest energy determined by the amplitude of the electric pulse. An advance or delay in applying a high-voltage pulse caused the ion dose and energy to decrease. A physical model incorporating three possible modes of ion implantation was proposed for the interpretation of the experimental results. If a laser plume was formed in the external field, ions were accelerated from the front of the dense plasma, and the ion current depended on the gas-dynamic expansion of the plume. The application of a high-voltage pulse, at the instant when the front approached the substrate, maintained the mode that was characteristic of the traditional plasma immersion ion implantation, and the ion current was governed by the dynamics of the plasma sheath in the substrate-to-target gap. In the case of an extremely late application of a high-voltage pulse, ions retained in the entire volume of the experimental chamber (as a result of the

  5. Atlas Pulsed Power Facility for High Energy Density Physics Experiments

    International Nuclear Information System (INIS)

    Miller, R.B.; Ballard, E.O.; Barr, G.W.; Bowman, D.W.; Chochrane, J.C.; Davis, H.A.; Elizondo, J.M.; Gribble, R.F.; Griego, J.R.; Hicks, R.D.; Hinckley, W.B.; Hosack, K.W.; Nielsen, K.E.; Parker, J.V.; Parsons, M.O.; Rickets, R.L.; Salazar, H.R.; Sanchez, P.G.; Scudder, D.W.; Shapiro, C.; Thompson, M.C.; Trainor, R.J.; Valdez, G.A.; Vigil, B.N.; Watt, R.G.; Wysock, F.J.

    1999-01-01

    The Atlas facility, now under construction at Los Alamos National Laboratory (LANL), will provide a unique capability for performing high-energy-density experiments in support of weapon-physics and basic-research programs. It is intended to be an international user facility, providing opportunities for researchers from national laboratories and academic institutions around the world. Emphasizing institutions around the world. Emphasizing hydrodynamic experiments, Atlas will provide the capability for achieving steady shock pressures exceeding 10-Mbar in a volume of several cubic centimeters. In addition, the kinetic energy associated with solid liner implosion velocities exceeding 12 km/s is sufficient to drive dense, hydrodynamic targets into the ionized regime, permitting the study of complex issues associated with strongly-coupled plasmas. The primary element of Atlas is a 23-MJ capacitor bank, comprised of 96 separate Marx generators housed in 12 separate oil-filled tanks, surrounding a central target chamber. Each tank will house two, independently-removable maintenance units, with each maintenance unit consisting of four Marx modules. Each Marx module has four capacitors that can each be charged to a maximum of 60 kilovolts. When railgap switches are triggered, the marx modules erect to a maximum of 240 kV. The parallel discharge of these 96 Marx modules will deliver a 30-MA current pulse with a 4-5-micros risetime to a cylindrical, imploding liner via 24 vertical, tri-plate, oil-insulated transmission lines. An experimental program for testing and certifying all Marx and transmission line components has been completed. A complete maintenance module and its associated transmission line (the First Article) are now under construction and testing. The current Atlas schedule calls for construction of the machine to be complete by August, 2000. Acceptance testing is scheduled to begin in November, 2000, leading to initial operations in January, 2001

  6. Experimental and theoretical studies of the physical processes occurring in thin plane targets irradiated by intense X-ray pulses

    International Nuclear Information System (INIS)

    Bugrov, A. E.; Burdonskii, I. N.; Gavrilov, V. V.; Gol'tsov, A. Yu.; Grabovskii, E. V.; Efremov, V. P.; Zhuzhukalo, E. V.; Zurin, M. V.; Koval'skii, N. G.; Kondrashov, V. N.; Oleinik, G. M.; Potapenko, A. I.; Samokhin, A. A.; Smirnov, V. P.; Fortov, V. E.; Frolov, I. N.

    2007-01-01

    Results are presented from experimental and theoretical studies of the interaction of intense X-ray pulses with different types of plane targets, including low-density (∼10 mg/cm 3 ) ones, in the Angara-5-1 facility. It is found experimentally that a dense low-temperature plasma forms on the target surface before the arrival of the main heating X-ray pulse. It is demonstrated that the contrast of the X-ray pulse can be increased by placing a thin organic film between the target and the discharge gap. The expansion velocity of the plasma created on the target surface irradiated by Z-pinch-produced X rays was found to be (3-4) x 10 6 cm/s. A comparison between the simulation and experimental results confirms the validity of the physical-mathematical model used

  7. High-energy infrared femtosecond pulses generated by dual-chirped optical parametric amplification.

    Science.gov (United States)

    Fu, Yuxi; Takahashi, Eiji J; Midorikawa, Katsumi

    2015-11-01

    We demonstrate high-energy infrared femtosecond pulse generation by a dual-chirped optical parametric amplification (DC-OPA) scheme [Opt. Express19, 7190 (2011)]. By employing a 100 mJ pump laser, a signal pulse energy exceeding 20 mJ at a wavelength of 1.4 μm was achieved before dispersion compensation. A total output energy of 33 mJ was recorded. Under a further energy scaling condition, the signal pulse was compressed to an almost transform-limited duration of 27 fs using a fused silica prism compressor. Since the DC-OPA scheme is efficient and energy scalable, design parameters for obtaining 100 mJ level infrared pulses are presented, which are suitable as driver lasers for the energy scaling of high-order harmonic generation with sub-keV photon energy.

  8. Studies of closure phenomena in pinholes irradiated by Nd laser pulses

    Energy Technology Data Exchange (ETDEWEB)

    Auerbach, J.M.; Holmes, N.C.; Hunt, J.T.; Linford, G.J.

    1978-08-21

    The plasma closure of spatial filter pinholes is a critical parameter in the performance of high energy glass laser systems. Using 50 to 100 J, 300 psec FWHM laser pulses on the Janus laser, an investigation has been made on closure effects in 300 ..mu..m to 500 ..mu..m diameter pinholes of various materials and thicknesses. Calorimetry measurements have yielded data on pinhole transmission and intensity loading on the periphery of the pinhole. Ultrafast streak photography measurements indicate effective closure velocities of 2 x 10/sup 7/ cm/sec to 5 x 10/sup 7/ cm/sec. Scattered light measurements have shown the transmission loss through a typical spatial filter configuration to be primarily refractive in nature.

  9. Studies of closure phenomena in pinholes irradiated by Nd laser pulses

    International Nuclear Information System (INIS)

    Auerbach, J.M.; Holmes, N.C.; Hunt, J.T.; Linford, G.J.

    1978-01-01

    The plasma closure of spatial filter pinholes is a critical parameter in the performance of high energy glass laser systems. Using 50 to 100 J, 300 psec FWHM laser pulses on the Janus laser, an investigation has been made on closure effects in 300 μm to 500 μm diameter pinholes of various materials and thicknesses. Calorimetry measurements have yielded data on pinhole transmission and intensity loading on the periphery of the pinhole. Ultrafast streak photography measurements indicate effective closure velocities of 2 x 10 7 cm/sec to 5 x 10 7 cm/sec. Scattered light measurements have shown the transmission loss through a typical spatial filter configuration to be primarily refractive in nature

  10. Triplet states of carotenoids from photosynthetic bacteria studied by nanosecond ultraviolet and electron pulse irradiation

    International Nuclear Information System (INIS)

    Bensasson, R.; Land, E.J.; Maudinas, B.

    1976-01-01

    Absorptions of the triplet excited states of five carotenoids (15,15'-cis phytoene, all-trans phytoene, zeta-carotene, spheroidene and spirillox-anthin), extracted from the photosynthetic bacteria Rhodopseudomonas spheroides and Rhodospirillum rubrum, have been detected in solution using pulse radiolysis and laser flash photolysis. Triplet lifetimes, extinction coefficients, lowest energy levels and quantum efficiencies of formation have been determined. Comparison of the carotenoid triplet energy levels with that of O 2 ('Δsub(g)) suggests that spirilloxanthin, spheroidene and possibly also zeta-carotene, would be expected to protect against photodynamic action caused by O 2 ('Δsub(g)), but not cis or trans phytoene. The S → T intersystem crossing efficiencies of all five polyenes were found to be low, being a few per cent or less. In their protective role these triplet states can only therefore be effectively reached via energy transfer from another triplet, except in the case of O 2 (Δsub(g)). The low crossover efficiencies also mean that light absorbed in such carotenoids in their possible role as accessory pigments would not be wasted in crossing over to the triplet state. (author)

  11. Application of thermoluminescence dosimeter on the measurement of hard X-ray pulse energy spectrum

    International Nuclear Information System (INIS)

    Song Zhaohui; Wang Baohui; Wang Kuilu; Hei Dongwei; Sun Fengrong; Li Gang

    2003-01-01

    This paper introduces the application of thermoluminescence dosimeter (TLD) which composed by TLD-3500 reader and GR-100 M chips on the measurement of hard X-ray pulse energy spectrum. The idea using Filter Fluorescence Method (FFM) and TLD to measure hard X-ray pulse energy spectrum (from 10 keV to 100 keV) is discussed in details. Considering all the factors of the measuring surrounding, the measurement system of hard X-ray pulse has been devised. The calibration technique of absolute energy response of TLD is established. This method has been applied successfully on the radiation parameters measurement of the huge pulse radiation device-high-power pulser I. Hard X-ray pulse energy spectrum data of the pulser are acquired

  12. The application of thermoluminescence dosimeter on the measurement of hard X-ray pulse energy spectrum

    International Nuclear Information System (INIS)

    Song Zhaohui; Wang Baohui; Wang Kuilu; Hei Dongwei; Sun Fengrong; Li Gang

    2001-01-01

    This paper introduce the application of thermoluminescence dosimeter (TLD) which composed by TLD-3500 Reader and TLD-100M chips on the measurement of hard X-ray pulse energy spectrum. The idea, using Filter Fluorescence Method (FFM) and TLD to measure hard X-ray pulse energy spectrum (from 10 keV to 100 keV), is discussed in details. Considering all the factors of the measuring surroundings, the measurement system of hard X-ray pulse has been devised. The calibration technique of absolute energy response of TLD is established. This method has been applied successfully on the radiation parameters measurement of the huge pulse radiation device -high-power pulser I. Hard X-ray pulse energy spectrum data of the pulser are acquired

  13. Dependence of Parameters of Laser-Produced Au Plasmas on the Incident Laser Energy of Sub-Nanosecond and Picosecond Laser Pulses

    International Nuclear Information System (INIS)

    Woryna, E.; Badziak, J.; Makowski, J.; Parys, P.; Vankov, A.B.; Wolowski, J.; Krasa, J.; Laska, L.; Rohlena, K.

    2001-01-01

    The parameters of Au plasma as functions of laser energy for ps pulses are presented and compared with the ones for sub-ns pulses at nearly the same densities of laser energy. The experiments were performed at the IPPLM with the use of CPA (chirped pulse amplification) Nd:glass laser system. Thick Au foil targets were irradiated by normally incident focused laser beams with maximum intensities of 8x10 16 and 2x10 14 W/cm 2 for ps and sub-ns laser pulses, respectively. The characteristics of ion streams were investigated with the use of ion diagnostics methods based on the time-of flight technique. In these experiments the laser energies were changed in the range from 90 to 700 mJ and the measurements were performed at a given focus position FP = 0 and along the target normal for both the laser pulses. The charge carried by the ions, the maximum ion velocities of fast and thermal ion groups, the maximum ion current density as well as the area of photopeak in dependence on the incident laser energy for sub-ns and ps pulses were investigated and discussed. (author)

  14. BRIEF COMMUNICATIONS: Experimental study of the energy balance in the interaction of a pulsed CO2 laser with metal and insulating targets in air

    Science.gov (United States)

    Babaeva, N. A.; Vas'kovskiĭ, Yu M.; Rovinskiĭ, R. E.; Ryabinkina, V. A.

    1991-09-01

    Measurements were made of components of the energy balance in the interaction of pulsed CO2 laser radiation with Dural, glass, quartz, ebonite, and Plexiglas in air at atmospheric pressure. At laser energy densities between 1 and 20 J/cm2 and in the spectral range 0.2-7 μm, the re-emission of radiation by the laser plasma was found to be less than 1 %. At energy densities exceeding 10 J/cm2, up to 90% of the laser energy failed to reach the irradiated surface.

  15. Pulse distortion, energy extraction, and ASE in an HF amplifier with angular multiplexing

    International Nuclear Information System (INIS)

    McGuire, E.J.

    1976-09-01

    It has been proposed that 1 ns pulses can be efficiently extracted from the e-beam initiated HF laser by angular multiplexing, i.e., filling the amplifier with the 1 ns pulses, 1 ns apart in time, each pulse at a slightly different angle; each pulse has an input intensity of 1 W/cm 2 per line and almost fills the amplifier. We have treated this in a one dimensional model, neglecting transverse amplified spontaneous emission. We conclude that the scheme is efficient, and that most of the pulses are amplified but not distorted. The first few pulses are distorted by transient effects and the last pulse has an enhanced tail. The ratio of peak pulse intensity to forward ASE at the output is 10 4 . We then include transverse ASE and find a drastically different situation. ASE saturates the inversion after a short time depending on pulse intensity (4 ns at I/sub o/ = 1 W/cm 2 , 7 ns at I/sub o/ = 100 W/cm 2 ). The saturation time is only weakly dependent on the transverse reflection coefficient. Calculations were done on an amplifier system designed for 10 KJ output. At an incident peak pulse intensity of 10 4 W/cm 2 -line (.77 MW/cm 2 for 77 lines) 2.5 KJ was obtained in amplified pulse energy, i.e., only 6 pulses of the 24 pulse train were fully amplified. The calculations indicate that double passing the pulse train through the amplifier would enhance the energy extracted

  16. Long-term energy output estimation for photovoltaic energy systems using synthetic solar irradiation data

    International Nuclear Information System (INIS)

    Celik, A.N.

    2003-01-01

    A general methodology is presented to estimate the monthly average daily energy output from photovoltaic energy systems. Energy output is estimated from synthetically generated solar radiation data. The synthetic solar radiation data are generated based on the cumulative frequency distribution of the daily clearness index, given as a function of the monthly clearness index. Two sets of synthetic solar irradiation data are generated: 3- and 4-day months. In the 3-day month, each month is represented by 3 days and in the 4-day month, by 4 days. The 3- and 4-day solar irradiation data are synthetically generated for each month and the corresponding energy outputs are calculated. A total of 8-year long measured hourly solar irradiation data, from five different locations in the world, is used to validate the new model. The monthly energy output values calculated from the synthetic solar irradiation data are compared to those calculated from the measured hour-by-hour data. It is shown that when the measured solar radiation data do not exist for a particular location or reduced data set is advantageous, the energy output from photovoltaic converters could be correctly calculated

  17. Ultrashort pulse energy distribution for propulsion in space

    Science.gov (United States)

    Bergstue, Grant Jared

    This thesis effort focuses on the development of a novel, space-based ultrashort pulse transmission system for spacecraft. The goals of this research include: (1) ultrashort pulse transmission strategies for maximizing safety and efficiency; (2) optical transmission system requirements; (3) general system requirements including control techniques for stabilization; (4) optical system requirements for achieving effective ablative propulsion at the receiving spacecraft; and (5) ultrashort pulse transmission capabilities required for future missions in space. A key element of the research is the multiplexing device required for aligning the ultrashort pulses from multiple laser sources along a common optical axis for transmission. This strategy enables access to the higher average and peak powers required for useful missions in space.

  18. High-energy, short-pulse, carbon-dioxide lasers

    International Nuclear Information System (INIS)

    Fenstermacher, C.A.

    1979-01-01

    Lasers for fusion application represent a special class of short-pulse generators; not only must they generate extremely short temporal pulses of high quality, but they must do this at ultra-high powers and satisfy other stringent requirements by this application. This paper presents the status of the research and development of carbon-dioxide laser systems at the Los Alamos Scientific Laboratory, vis-a-vis the fusion requirements

  19. High-energy few-cycle pulse compression through self-channeling in gases

    International Nuclear Information System (INIS)

    Hauri, C.; Merano, M.; Trisorio, A.; Canova, F.; Canova, L.; Lopez-Martens, R.; Ruchon, T.; Engquist, A.; Varju, K.; Gustafsson, E.

    2006-01-01

    Complete test of publication follows. Nonlinear spectral broadening of femtosecond optical pulses by intense propagation in a Kerr medium followed by temporal compression constitutes the Holy Grail for ultrafast science since it allows the generation of intense few-cycle optical transients from longer pulses provided by now commercially available femtosecond lasers. Tremendous progress in high-field and attosecond physics achieved in recent years has triggered the need for efficient pulse compression schemes producing few-cycle pulses beyond the mJ level. We studied a novel pulse compression scheme based on self-channeling in gases, which promises to overcome the energy constraints of hollow-core fiber compression techniques. Fundamentally, self-channeling at high laser powers in gases occurs when the self-focusing effect in the gas is balanced through the dispersion induced by the inhomogeneous refractive index resulting from optically-induced ionization. The high nonlinearity of the ionization process poses great technical challenges when trying to scale this pulse compression scheme to higher energies input energies. Light channels are known to be unstable under small fluctuations of the trapped field that can lead to temporal and spatial beam breakup, usually resulting in the generation of spectrally broad but uncompressible pulses. Here we present experimental results on high-energy pulse compression of self-channeled 40-fs pulses in pressure-gas cells. In the first experiment, performed at the Lund Laser Center in Sweden, we identified a particular self-channeling regime at lower pulse energies (0.8 mJ), in which the ultrashort pulses are generated with negative group delay dispersion (GDD) such that they can be readily compressed down to near 10-fs through simple material dispersion. Pulse compression is efficient (70%) and exhibits exceptional spatial and temporal beam stability. In a second experiment, performed at the LOA-Palaiseau in France, we

  20. Pulsed high energy synthesis of fine metal powders

    Science.gov (United States)

    Witherspoon, F. Douglas (Inventor); Massey, Dennis W. (Inventor)

    1999-01-01

    Repetitively pulsed plasma jets generated by a capillary arc discharge at high stagnation pressure (>15,000 psi) and high temperature (>10,000 K) are utilized to produce 0.1-10 .mu.m sized metal powders and decrease cost of production. The plasma jets impact and atomize melt materials to form the fine powders. The melt can originate from a conventional melt stream or from a pulsed arc between two electrodes. Gas streams used in conventional gas atomization are replaced with much higher momentum flux plasma jets. Delivering strong incident shocks aids in primary disintegration of the molten material. A series of short duration, high pressure plasma pulses fragment the molten material. The pulses introduce sharp velocity gradients in the molten material which disintegrates into fine particles. The plasma pulses have peak pressures of approximately one kilobar. The high pressures improve the efficiency of disintegration. High gas flow velocities and pressures are achieved without reduction in gas density. Repetitively pulsed plasma jets will produce powders with lower mean size and narrower size distribution than conventional atomization techniques.

  1. Electromagnetic pulse compression and energy localization in quantum plasmas

    International Nuclear Information System (INIS)

    Hefferon, Gareth; Sharma, Ashutosh; Kourakis, Ioannis

    2010-01-01

    The evolution of the intensity of a relativistic laser beam propagating through a dense quantum plasma is investigated, by considering different plasma regimes. A cold quantum fluid plasma and then a thermal quantum description(s) is (are) adopted, in comparison with the classical case of reference. Considering a Gaussian beam cross-section, we investigate both the longitudinal compression and lateral/longitudinal localization of the intensity of a finite-radius electromagnetic pulse. By employing a quantum plasma fluid model in combination with Maxwell's equations, we rely on earlier results on the quantum dielectric response, to model beam-plasma interaction. We present an extensive parametric investigation of the dependence of the longitudinal pulse compression mechanism on the electron density in cold quantum plasmas, and also study the role of the Fermi temperature in thermal quantum plasmas. Our numerical results show pulse localization through a series of successive compression cycles, as the pulse propagates through the plasma. A pulse of 100 fs propagating through cold quantum plasma is compressed to a temporal size of ∼1.35 attosecond and a spatial size of ∼1.08.10 -3 cm. Incorporating Fermi pressure via a thermal quantum plasma model is shown to enhance localization effects. A 100 fs pulse propagating through quantum plasma with a Fermi temperature of 350 K is compressed to a temporal size of ∼0.6 attosecond and a spatial size of ∼2.4.10 -3 cm.

  2. High energy argon ion irradiations of polycrystalline iron

    International Nuclear Information System (INIS)

    Dunlop, A.; Lesueur, D.; Lorenzelli, N.; Boulanger, L.

    1986-09-01

    We present here the results of our recent irradiations of polycrystalline iron targets with very energetic (1.76 GeV) Ar ions. The targets consist of piles of thin iron samples, the total thickness of each target being somewhat greater than the theoretical range (450 μm) of the ions. We can thus separate the phenomena which occur at different average energies of the ions and study during the slowing-down process: the different types of induced nuclear reactions. They allow us to determine the experimental range of the ions, the defect profiles in the targets, the structure of the displacement cascades (electron microscopy) and their stability

  3. Energy deposition, heat flow, and rapid solidification during laser and electron beam irradiation of materials

    Energy Technology Data Exchange (ETDEWEB)

    White, C.W.; Aziz, M.J.

    1985-10-01

    The fundamentals of energy deposition, heat flow, and rapid solidification during energy deposition from lasers and electron beams is reviewed. Emphasis is placed on the deposition of energy from pulsed sources (10 to 100 ns pulse duration time) in order to achieve high heating and cooling rates (10/sup 8/ to 10/sup 10/ /sup 0/C/s) in the near surface region. The response of both metals and semiconductors to pulsed energy deposition is considered. Guidelines are presented for the choice of energy source, wavelength, and pulse duration time.

  4. High-energy, twelve-channel laser facility (DEFIN) for spherical irradiation of thermonuclear targets

    International Nuclear Information System (INIS)

    Basov, N.G.; Danilov, A.E.; Krokhin, O.N.; Kruglov, B.V.; Mikhailov, Yu.A.; Sklizkov, G.V.; Fedotov, S.I.; Fedorov, A.N.

    This paper describes a high-energy, twelve-channel laser facility (DELFIN) intended for high-temperature heating of thermonuclear targets with spherical symmetry. The facility includes a neodymium-glass laser with the ultimate radiation energy of 10 kJ, a pulse length of approximately 10 -10 to 10 -9 s, beam divergence of 5 x 10 -4 radians, a vacuum chamber in which laser radiation interacts with the plasma, and a system of diagnostic instrumentation for the observation of laser beam and plasma parameters. Described are the optical scheme and construction details of the laser facility. Presented is an analysis of focusing schemes for target irradiation and described is the focusing scheme of the DELFIN facility, which is capable of attaining a high degree of spherical symmetry in irradiating targets with maximum beam intensity at the target surface of approximately 10 15 W/cm 2 . This paper examines the most important problems connected with the physical investigations of thermonuclear laser plasma and the basic diagnostic problems involved in their solution

  5. Basic principles of thermo-acoustic energy and temporal profile detection of microwave pulses

    CERN Document Server

    Andreev, V G; Vdovin, V A

    2001-01-01

    Basic principles of a thermo-acoustic method developed for the detection of powerful microwave pulses of nanosecond duration are discussed.A proposed method is based on the registration of acoustic pulse profile originated from the thermal expansion of the volume where microwave energy was absorbed.The amplitude of excited acoustic transient is proportional to absorbed microwave energy and its temporal profile resembles one of a microwave pulse when certain conditions are satisfied.The optimal regimes of microwave pulse energy detection and sensitivity of acoustic transient registration with piezo-transducer are discussed.It was demonstrated that profile of a microwave pulse could be detected with temporal resolution of 1 - 3 nanosecond.

  6. Characteristics of pulsed photo-stimulated luminescence and thermoluminescence for the identification of gamma irradiated poultry eggs

    International Nuclear Information System (INIS)

    Bhatti, I.A.; Kwon, J.-H.; Ur-rehman, S.

    2007-01-01

    Pulsed photo-stimulated luminescence (PPSL) is a simple screening method that can be employed qualitatively at the spot for the detection of eggs treated with ionizing radiation. Due to the variations in the results during storage, the eggs of ostrich, duck, hen, and quail were irradiated to doses of 0, 1, 2, and 3 kGy. Most of the samples were incorrectly identified during storage after four months of irradiation. Thermoluminescence (TL) technique was also tried by using egg shells in order to confirm the irradiation treatment in eggs. TL glow curves were recorded between the temperatures 50 degree C to 400 degree C at the rate of 5 degree/s for all the control and irradiated samples. On the basis of integrated areas of first glow curves (TL1), the glow curve ratios (TL1/TL2) and the shapes of maxima of TL1, the irradiation treatment of all the eggs was confirmed. Furthermore, the presence of calcite and aragonite minerals that cause the TL signal in the egg shells were studied using X-ray diffraction spectrometry. (authors)

  7. Influence of repetitive pulsed laser irradiation on the surface characteristics of an aluminum alloy in the melting regime

    International Nuclear Information System (INIS)

    Choi, Sung Ho; Jhang, Kyung Young

    2015-01-01

    We have investigated the influence of repetitive near-infrared (NIR) pulsed laser shots in the melting regime on the surface characteristics of an aluminum 6061-T6 alloy. Characteristics of interest include surface morphology, surface roughness, and surface hardness in the melted zone as well as the size of the melted zone. For this study, the proper pulse energy for inducing surface melting at one shot is selected using numerical simulations that calculate the variation in temperature at the laser beam spot for various input pulse energies in order to find the proper pulse energy for raising the temperature to the melting point. In this study, 130 mJ was selected as the input energy for a Nd:YAG laser pulse with a duration of 5 ns. The size of the melted zone measured using optical microscopy (OM) increased logarithmically with an increasing shot number. The surface morphology observed by scanning electron microscopy (SEM) clearly showed a re-solidified microstructure evolution after surface melting. The surface roughness and hardness were measured by atomic force microscopy (AFM) and nano-indentation, respectively. The surface roughness showed almost no variation due to the surface texturing after laser shots over 10. The hardness inside the melted zone was lower than that outside the zone because the β'' phase was transformed to a β phase or dissolved into a matrix.

  8. Hadronic vs. electromagnetic pulse shape discrimination in CsI(Tl) for high energy physics experiments

    Science.gov (United States)

    Longo, S.; Roney, J. M.

    2018-03-01

    Pulse shape discrimination using CsI(Tl) scintillators to perform neutral hadron particle identification is explored with emphasis towards application at high energy electron-positron collider experiments. Through the analysis of the pulse shape differences between scintillation pulses from photon and hadronic energy deposits using neutron and proton data collected at TRIUMF, it is shown that the pulse shape variations observed for hadrons can be modelled using a third scintillation component for CsI(Tl), in addition to the standard fast and slow components. Techniques for computing the hadronic pulse amplitudes and shape variations are developed and it is shown that the intensity of the additional scintillation component can be computed from the ionization energy loss of the interacting particles. These pulse modelling and simulation methods are integrated with GEANT4 simulation libraries and the predicted pulse shape for CsI(Tl) crystals in a 5 × 5 array of 5 × 5 × 30 cm3 crystals is studied for hadronic showers from 0.5 and 1 GeV/c KL0 and neutron particles. Using a crystal level and cluster level approach for photon vs. hadron cluster separation we demonstrate proof-of-concept for neutral hadron detection using CsI(Tl) pulse shape discrimination in high energy electron-positron collider experiments.

  9. Influence of energy and duration of laser pulses on stability of dielectric nanoparticles in optical trap

    International Nuclear Information System (INIS)

    Ho Quang Quy; Mai Van Luu; Hoang Dinh Hai

    2010-01-01

    In this article the gradient force of optical trap using two counter- propagating pulsed Gaussian beam and the Brownian motion in optical force field are investigated. The influence of the energy and duration time of optical pulsed Gaussian beams on stability of nano-particle in trap is simulated and discussed. (author)

  10. Solar Irradiance Measurements Using Smart Devices: A Cost-Effective Technique for Estimation of Solar Irradiance for Sustainable Energy Systems

    Directory of Open Access Journals (Sweden)

    Hussein Al-Taani

    2018-02-01

    Full Text Available Solar irradiance measurement is a key component in estimating solar irradiation, which is necessary and essential to design sustainable energy systems such as photovoltaic (PV systems. The measurement is typically done with sophisticated devices designed for this purpose. In this paper we propose a smartphone-aided setup to estimate the solar irradiance in a certain location. The setup is accessible, easy to use and cost-effective. The method we propose does not have the accuracy of an irradiance meter of high precision but has the advantage of being readily accessible on any smartphone. It could serve as a quick tool to estimate irradiance measurements in the preliminary stages of PV systems design. Furthermore, it could act as a cost-effective educational tool in sustainable energy courses where understanding solar radiation variations is an important aspect.

  11. Field emission study from an array of hierarchical micro protrusions on stainless steel surface generated by femtosecond pulsed laser irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Singh, A.K., E-mail: anilks@barc.gov.in [Laser & Plasma Technology Division, BARC, Mumbai, 400085 (India); Suryawanshi, Sachin R.; More, M.A. [Department of Physics, Savitribai Phule Pune University, Pune, 411007 (India); Basu, S. [Solid State Physics Division, BARC, Mumbai, 40085 (India); Sinha, Sucharita [Laser & Plasma Technology Division, BARC, Mumbai, 400085 (India)

    2017-02-28

    Highlights: • Array of self assembled micro-protrusions have been generated on stainless steel surfaces by femtosecond pulsed laser irradiation. • Density of the formed micro-protrusions is ∼5.6 × 105 protrusions/cm{sup 2}. • Laser treated surface is mainly composed of iron oxide and cementite phases. • Micro-structured sample has shown good field emission properties – low turn on field, high field enhancement factor and stable emission current. - Abstract: This paper reports our results on femtosecond (fs) pulsed laser induced surface micro/nano structuring of stainless steel 304 (SS 304) samples and their characterization in terms of surface morphology, formed material phases on laser irradiation and field emission studies. Our investigations reveal that nearly uniform and dense array of hierarchical micro-protrusions (density: ∼5.6 × 10{sup 5} protrusions/cm{sup 2}) is formed upon laser treatment. Typical tip diameters of the generated protrusions are in the range of 2–5 μm and these protrusions are covered with submicron sized features. Grazing incidence X-ray diffraction (GIXRD) analysis of the laser irradiated sample surface has shown formation mainly of iron oxides and cementite (Fe{sub 3}C) phases in the treated region. These laser micro-structured samples have shown good field emission properties such as low turn on field (∼4.1 V/μm), high macroscopic field enhancement factor (1830) and stable field emission current under ultra high vacuum conditions.

  12. Efficient delivery of 60 J pulse energy of long pulse Nd:YAG laser ...

    Indian Academy of Sciences (India)

    2014-02-09

    Feb 9, 2014 ... Most of today's industrial Nd:YAG lasers use fibre-optic beam delivery. In such lasers, fibre core diameter is an important consideration in deploying a beam delivery system. Using a smaller core diameter fibre allows higher irradiances at focus position, less degradation of beam quality, and a larger ...

  13. Heat wave propagation in a thin film irradiated by ultra-short laser pulses

    International Nuclear Information System (INIS)

    Yoo, Jae Gwon; Kim, Cheol Jung; Lim, C. H.

    2004-01-01

    A thermal wave solution of a hyperbolic heat conduction equation in a thin film is developed on the basis of the Green's function formalism. Numerical computations are carried out to investigate the temperature response and the propagation of the thermal wave inside a thin film due to a heat pulse generated by ultra-short laser pulses with various laser pulse durations and thickness of the film

  14. Microjet formation and hard x-ray production from a liquid metal target irradiated by intense femtosecond laser pulses

    Energy Technology Data Exchange (ETDEWEB)

    Lar' kin, A., E-mail: alexeylarkin@yandex.ru; Uryupina, D.; Ivanov, K.; Savel' ev, A., E-mail: abst@physics.msu.ru [International Laser Center and Faculty of Physics, Lomonosov Moscow State University, Moscow 119991 (Russian Federation); Bonnet, T.; Gobet, F.; Hannachi, F.; Tarisien, M.; Versteegen, M. [Centre d' Études Nucléaires de Bordeaux-Gradignan, University of Bordeaux-CNRS-IN2P3, 33170 Gradignan (France); Spohr, K. [School of Engineering, University of the West of Scotland, Paisley, Scotland PA1 2BE (United Kingdom); Breil, J.; Chimier, B.; Dorchies, F.; Fourment, C.; Leguay, P.-M.; Tikhonchuk, V. T. [Centre Lasers Intenses et Applications, University of Bordeaux-CNRS-CEA, Talence 33405 (France)

    2014-09-15

    By using a liquid metal as a target one may significantly enhance the yield of hard x-rays with a sequence of two intense femtosecond laser pulses. The influence of the time delay between the two pulses is studied experimentally and interpreted with numerical simulations. It was suggested that the first arbitrary weak pulse produces microjets from the target surface, while the second intense pulse provides an efficient electron heating and acceleration along the jet surface. These energetic electrons are the source of x-ray emission while striking the target surface. The microjet formation is explained based on the results given by both optical diagnostics and hydrodynamic modeling by a collision of shocks originated from two distinct zones of laser energy deposition.

  15. Microjet formation and hard x-ray production from a liquid metal target irradiated by intense femtosecond laser pulses

    International Nuclear Information System (INIS)

    Lar'kin, A.; Uryupina, D.; Ivanov, K.; Savel'ev, A.; Bonnet, T.; Gobet, F.; Hannachi, F.; Tarisien, M.; Versteegen, M.; Spohr, K.; Breil, J.; Chimier, B.; Dorchies, F.; Fourment, C.; Leguay, P.-M.; Tikhonchuk, V. T.

    2014-01-01

    By using a liquid metal as a target one may significantly enhance the yield of hard x-rays with a sequence of two intense femtosecond laser pulses. The influence of the time delay between the two pulses is studied experimentally and interpreted with numerical simulations. It was suggested that the first arbitrary weak pulse produces microjets from the target surface, while the second intense pulse provides an efficient electron heating and acceleration along the jet surface. These energetic electrons are the source of x-ray emission while striking the target surface. The microjet formation is explained based on the results given by both optical diagnostics and hydrodynamic modeling by a collision of shocks originated from two distinct zones of laser energy deposition

  16. Microjet formation and hard x-ray production from a liquid metal target irradiated by intense femtosecond laser pulses

    Science.gov (United States)

    Lar'kin, A.; Uryupina, D.; Ivanov, K.; Savel'ev, A.; Bonnet, T.; Gobet, F.; Hannachi, F.; Tarisien, M.; Versteegen, M.; Spohr, K.; Breil, J.; Chimier, B.; Dorchies, F.; Fourment, C.; Leguay, P.-M.; Tikhonchuk, V. T.

    2014-09-01

    By using a liquid metal as a target one may significantly enhance the yield of hard x-rays with a sequence of two intense femtosecond laser pulses. The influence of the time delay between the two pulses is studied experimentally and interpreted with numerical simulations. It was suggested that the first arbitrary weak pulse produces microjets from the target surface, while the second intense pulse provides an efficient electron heating and acceleration along the jet surface. These energetic electrons are the source of x-ray emission while striking the target surface. The microjet formation is explained based on the results given by both optical diagnostics and hydrodynamic modeling by a collision of shocks originated from two distinct zones of laser energy deposition.

  17. Irradiation of amelanotic melanoma cells with 532 nm high peak power pulsed laser radiation in the presence of the photothermal sensitizer Cu(II)-hematoporphyrin: a new approach to cell photoinactivation.

    Science.gov (United States)

    Soncin, M; Busetti, A; Fusi, F; Jori, G; Rodgers, M A

    1999-06-01

    Cu(II)-hematoporphyrin (CuHp) was efficiently accumulated by B78H1 amelanotic melanoma cells upon incubation with porphyrin concentrations up to 52 microM. When the cells incubated for 18 h with 13 microM CuHp were irradiated with 532 nm light from a Q-switched Nd: YAG laser operated in a pulsed mode (10 ns pulses, 10 Hz) a significant decrease in cell survival was observed. The cell photoinactivation was not the consequence of a photodynamic process, as CuHp gave no detectable triplet signal upon laser flash photolysis excitation and no decrease in cell survival was observed upon continuous wave irradiation. Thus, it is likely that CuHp sensitization takes place by photothermal pathways. The efficiency of the photoprocess was modulated by different parameters; thus, while varying the amount of added CuHp in the 3.25-26 microM range had little effect, pulse energies larger than 50 mJ and irradiation times of at least 120 s were necessary to induce a cell inactivation of about 50%. The porphyrin-cell incubation time prior to irradiation had a major influence on cell survival, suggesting that the nature of the CuHp microenvironment can control the efficiency of photothermal sensitization.

  18. High-energy-throughput pulse compression by off-axis group-delay compensation in a laser-induced filament

    International Nuclear Information System (INIS)

    Voronin, A. A.; Alisauskas, S.; Muecke, O. D.; Pugzlys, A.; Baltuska, A.; Zheltikov, A. M.

    2011-01-01

    Off-axial beam dynamics of ultrashort laser pulses in a filament enable a radical energy-throughput improvement for filamentation-assisted pulse compression. We identify regimes where a weakly diverging wave, produced on the trailing edge of the pulse, catches up with a strongly diverging component, arising in the central part of the pulse, allowing sub-100-fs millijoule infrared laser pulses to be compressed to 20-25-fs pulse widths with energy throughputs in excess of 70%. Theoretical predictions have been verified by experimental results on filamentation-assisted compression of 70-fs, 1.5-μm laser pulses in high-pressure argon.

  19. The effect of pulse current on energy saving during Electrochemical Chloride Extraction (ECE) in concrete

    DEFF Research Database (Denmark)

    Sun, Tian R.; Geiker, Mette R.; Ottosen, Lisbeth M.

    2012-01-01

    Energy consumption is a factor influencing the cost of Electrochemical Chloride Extraction (ECE) in concrete. The aims of this work were to investigate the possibility for energy saving when using a pulsed electric field during ECE and the effect of the pulsed current on removal of chloride. Four...... experiments with artificially polluted concrete under same charge transfer were conducted. Results showed that the energy consumption was decreased 15% by pulse current in experiments with 0.2 mA/cm2 current density, which was higher than that of 0.1 mA/cm2 experiments with a decrease of 9.6%. When comparing...... the voltage drop at different parts of the experimental cells, it was found that the voltage drop of the area across the concrete was the major contributor to energy consumption, and results indicated that the pulse current could decrease the voltage drop of this part by re-distribution of ions in pore fluid...

  20. High beam quality and high energy short-pulse laser with MOPA

    Science.gov (United States)

    Jin, Quanwei; Pang, Yu; Jiang, JianFeng; Tan, Liang; Cui, Lingling; Wei, Bin; Sun, Yinhong; Tang, Chun

    2018-03-01

    A high energy, high beam quality short-pulse diode-pumped Nd:YAG master oscillator power-amplifier (MOPA) laser with two amplifier stages is demonstrated. The two-rod birefringence compensation was used as beam quality controlling methods, which presents a short-pulse energy of 40 mJ with a beam quality value of M2 = 1.2 at a repetition rate of 400Hz. The MOPA system delivers a short-pulse energy of 712.5 mJ with a pulse width of 12.4 ns.The method of spherical aberration compensation is improved the beam quality, a M2 factor of 2.3 and an optical-to-optical efficiency of 27.7% is obtained at the maximum laser out power.The laser obtained 1.4J out energy with polarization integration.

  1. HIGH ENERGY REPLACEMENT FOR TEFLON PROPELLANT IN PULSED PLASMA THRUSTERS, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This program will utilize a well-characterized Pulsed Plasma Thruster (PPT) to test experimental high-energy extinguishable solid propellants (HE), instead of...

  2. Remedial pulse programme for the production of monoenergetic ion beams of low energy

    International Nuclear Information System (INIS)

    Olubuyide, O.A.

    1975-01-01

    The technique involves an extension of sequential pulse techniques. An ion swarm is produced in a conventional mass-spectrometer ion source by a short electron beam pulse. Immediately, this swarm is accelerated impulsively by a short high voltage pulse on the repeller. The principal disadvantage of impulsive acceleration is that the final energy distribution of the ion swarm is broad especially at the lowest energies. At some instant during the passage of the ion swarm across the chamber second pulse is applied to the repeller--a ''remedial'' pulse which will accelerate the ions throughout the remainder of their passage and whose amplitude will be time-dependent. Slower ions must travel a greater distance in this ''remedial'' field than faster ions and will experience a proportionately greater increase in velocity from it. In this way, the remedial pulse can cause all the ions to acquire the same velocity at the exit slit. A limited experimental investigation has been made to examine the application of the proposed remedial pulse technique to existing ion sources. Application of the remedial pulse to impulsively-accelerated ion swarms reduced the energy distribution in the manner predicted by the theory but the quantitative reduction measured experimentally--a factor of approximately 2--was substantially less than the theoretical prediction of a factor of approximately 4. The limitations were characterized and a means of overcoming them was suggested in a new ion source of improved design. (Diss. Abstr. Int., B)

  3. Thermal wave propagation in the pulsed laser irradiation of media with thermal memory

    International Nuclear Information System (INIS)

    Galovic, S.; Kostoski, D.; Stamboliev, G.; Suljovrujic, E.

    2002-01-01

    Complete text of publication follows. If a sample is exposed to the influence of laser radiation part of its energy is absorbed and converted in heat. The heat generated in this way is transferred through the sample as heat waves, resulting in various effects (so called photothermal effects). A large number of nondestructive diagnostic methods are based on recording of these effects. It is necessary to create a good model in order to understand and correctly describe the measured results of heat transfer in different media. In a certain number of materials and structures, such as complex biological materials, polymers, metals excited by very short laser pulses etc., the property of thermal memory has been experimentally observed. Starting with the hyperbolic equation that describes heat transfer processes of such media, in this paper has been developed a model of laser-excited heat waves propagation in order to enable application of photothermal techniques in characterization of these media. The cases of optically opaque and transparent samples are considered. The influence of various backings on photothermal waves has also been analyzed. The results are compared to the previous models

  4. Novel high-frequency energy-efficient pulsed-dc generator for capacitively coupled plasma discharge

    Science.gov (United States)

    Mamun, Md Abdullah Al; Furuta, Hiroshi; Hatta, Akimitsu

    2018-03-01

    The circuit design, assembly, and operating tests of a high-frequency and high-voltage (HV) pulsed dc generator (PDG) for capacitively coupled plasma (CCP) discharge inside a vacuum chamber are reported. For capacitive loads, it is challenging to obtain sharp rectangular pulses with fast rising and falling edges, requiring intense current for quick charging and discharging. The requirement of intense current generally limits the pulse operation frequency. In this study, we present a new type of PDG consisting of a pair of half-resonant converters and a constant current-controller circuit connected with HV solid-state power switches that can deliver almost rectangular high voltage pulses with fast rising and falling edges for CCP discharge. A prototype of the PDG is assembled to modulate from a high-voltage direct current (HVdc) input into a pulsed HVdc output, while following an input pulse signal and a set current level. The pulse rise time and fall time are less than 500 ns and 800 ns, respectively, and the minimum pulse width is 1 µs. The maximum voltage for a negative pulse is 1000 V, and the maximum repetition frequency is 500 kHz. During the pulse on time, the plasma discharge current is controlled steadily at the set value. The half-resonant converters in the PDG perform recovery of the remaining energy from the capacitive load at every termination of pulse discharge. The PDG performed with a high energy efficiency of 85% from the HVdc input to the pulsed dc output at a repetition rate of 1 kHz and with stable plasma operation in various discharge conditions. The results suggest that the developed PDG can be considered to be more efficient for plasma processing by CCP.

  5. Novel high-frequency energy-efficient pulsed-dc generator for capacitively coupled plasma discharge.

    Science.gov (United States)

    Mamun, Md Abdullah Al; Furuta, Hiroshi; Hatta, Akimitsu

    2018-03-01

    The circuit design, assembly, and operating tests of a high-frequency and high-voltage (HV) pulsed dc generator (PDG) for capacitively coupled plasma (CCP) discharge inside a vacuum chamber are reported. For capacitive loads, it is challenging to obtain sharp rectangular pulses with fast rising and falling edges, requiring intense current for quick charging and discharging. The requirement of intense current generally limits the pulse operation frequency. In this study, we present a new type of PDG consisting of a pair of half-resonant converters and a constant current-controller circuit connected with HV solid-state power switches that can deliver almost rectangular high voltage pulses with fast rising and falling edges for CCP discharge. A prototype of the PDG is assembled to modulate from a high-voltage direct current (HVdc) input into a pulsed HVdc output, while following an input pulse signal and a set current level. The pulse rise time and fall time are less than 500 ns and 800 ns, respectively, and the minimum pulse width is 1 µs. The maximum voltage for a negative pulse is 1000 V, and the maximum repetition frequency is 500 kHz. During the pulse on time, the plasma discharge current is controlled steadily at the set value. The half-resonant converters in the PDG perform recovery of the remaining energy from the capacitive load at every termination of pulse discharge. The PDG performed with a high energy efficiency of 85% from the HVdc input to the pulsed dc output at a repetition rate of 1 kHz and with stable plasma operation in various discharge conditions. The results suggest that the developed PDG can be considered to be more efficient for plasma processing by CCP.

  6. Attosecond time-energy structure of X-ray free-electron laser pulses

    Science.gov (United States)

    Hartmann, N.; Hartmann, G.; Heider, R.; Wagner, M. S.; Ilchen, M.; Buck, J.; Lindahl, A. O.; Benko, C.; Grünert, J.; Krzywinski, J.; Liu, J.; Lutman, A. A.; Marinelli, A.; Maxwell, T.; Miahnahri, A. A.; Moeller, S. P.; Planas, M.; Robinson, J.; Kazansky, A. K.; Kabachnik, N. M.; Viefhaus, J.; Feurer, T.; Kienberger, R.; Coffee, R. N.; Helml, W.

    2018-04-01

    The time-energy information of ultrashort X-ray free-electron laser pulses generated by the Linac Coherent Light Source is measured with attosecond resolution via angular streaking of neon 1s photoelectrons. The X-ray pulses promote electrons from the neon core level into an ionization continuum, where they are dressed with the electric field of a circularly polarized infrared laser. This induces characteristic modulations of the resulting photoelectron energy and angular distribution. From these modulations we recover the single-shot attosecond intensity structure and chirp of arbitrary X-ray pulses based on self-amplified spontaneous emission, which have eluded direct measurement so far. We characterize individual attosecond pulses, including their instantaneous frequency, and identify double pulses with well-defined delays and spectral properties, thus paving the way for X-ray pump/X-ray probe attosecond free-electron laser science.

  7. One-Pot Hybrid SnO2 /Poly(methyl methacrylate) Nanocomposite Formation through Pulsed Laser Irradiation.

    Science.gov (United States)

    Caputo, Gianvito; Scarpellini, Alice; Palazon, Francisco; Athanassiou, Athanassia; Fragouli, Despina

    2017-06-20

    The localized in situ formation of tin dioxide (SnO 2 ) nanoparticles embedded in poly(methyl methacrylate) (PMMA) films is presented. This is achieved by the photoinduced conversion of the tin acetate precursor included in polymeric films, through controlled UV or visible pulsed laser irradiation at λ=355 and 532 nm, respectively. The evolution of the formation of nanoparticles is followed by UV/Vis spectroscopy and shows that their growth is affected in different ways by the laser pulses at the two applied wavelengths. This, in combination with electron microscopy analysis, reveals that, depending on the irradiation wavelength, the size of the nanoparticles in the final nanocomposites differs. This difference is attributed to distinct mechanistic pathways that lead to the synthesis of small nanoparticles (from 1.5 to 4.5 nm) at λ=355 nm, whereas bigger ones (from 5 to 16 nm) are formed at λ=532 nm. At the same time, structural studies with both X-ray and electron diffraction measurements demonstrate the crystallinity of SnO 2 nanoparticles in both cases, whereas XPS analysis confirms the light-induced oxidation of tin acetate into SnO 2 . Taken all together, it is demonstrated that the pulsed laser irradiation at λ=355 and 532 nm leads to the formation of SnO 2 nanoparticles with defined features highly dispersed in PMMA solid matrices. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Irradiation of cells by single and double pulses of high intensity radiation: oxygen sensitization and diffusion kinetics

    International Nuclear Information System (INIS)

    Epp, E.R.; Ling, C.C.; Weiss, H.

    1976-01-01

    This paper discusses advances made on both experimental and theoretical approaches involving single and double pulses of high intensity ionizing radiation delivered to cultured bacterial and mammalian cells where the effect of oxygen is concerned. Information gained on the lifetime of oxygen-sensitive species suspected to be produced in critical molecules in irradiated cells and perhaps intimately related to the still unknown mechanisms of oxygen sensitization is described. The diffusion characteristics of oxygen at the cellular level obtained from experimental data are discussed. Current knowledge on intracellular radiolytic oxygen depletion is also presented. Future work on the use of high intensity pulsed radiation as a tool in cellular radiobiological research is outlined. It is expected that obtaining knowledge of the time available for damaged molecules to enter into chemical reactions may lead to insights into the mechanisms of radiation injury in cells, such as those involved in the oxygen effect. (Auth.)

  9. Imaging the ultrafast Kerr effect, free carrier generation, relaxation and ablation dynamics of Lithium Niobate irradiated with femtosecond laser pulses

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Lechuga, Mario, E-mail: mario@io.cfmac.csic.es; Siegel, Jan, E-mail: j.siegel@io.cfmac.csic.es; Hernandez-Rueda, Javier; Solis, Javier [Laser Processing Group, Instituto de Optica, CSIC, Serrano 121, 28006 Madrid (Spain)

    2014-09-21

    The interaction of high-power single 130 femtosecond (fs) laser pulses with the surface of Lithium Niobate is experimentally investigated in this work. The use of fs-resolution time-resolved microscopy allows us to separately observe the instantaneous optical Kerr effect induced by the pulse and the generation of a free electron plasma. The maximum electron density is reached 550 fs after the peak of the Kerr effect, confirming the presence of a delayed carrier generation mechanism. We have also observed the appearance of transient Newton rings during the ablation process, related to optical interference of the probe beam reflected at the front and back surface of the ablating layer. Finally, we have analyzed the dynamics of the photorefractive effect on a much longer time scale by measuring the evolution of the transmittance of the irradiated area for different fluences below the ablation threshold.

  10. Imaging the ultrafast Kerr effect, free carrier generation, relaxation and ablation dynamics of Lithium Niobate irradiated with femtosecond laser pulses

    International Nuclear Information System (INIS)

    Garcia-Lechuga, Mario; Siegel, Jan; Hernandez-Rueda, Javier; Solis, Javier

    2014-01-01

    The interaction of high-power single 130 femtosecond (fs) laser pulses with the surface of Lithium Niobate is experimentally investigated in this work. The use of fs-resolution time-resolved microscopy allows us to separately observe the instantaneous optical Kerr effect induced by the pulse and the generation of a free electron plasma. The maximum electron density is reached 550 fs after the peak of the Kerr effect, confirming the presence of a delayed carrier generation mechanism. We have also observed the appearance of transient Newton rings during the ablation process, related to optical interference of the probe beam reflected at the front and back surface of the ablating layer. Finally, we have analyzed the dynamics of the photorefractive effect on a much longer time scale by measuring the evolution of the transmittance of the irradiated area for different fluences below the ablation threshold.

  11. Frontiers in pulse-power-based high energy density plasma physics and its applications

    International Nuclear Information System (INIS)

    Horioka, Kazuhiko

    2008-03-01

    The papers in this volume of report were presented at the Symposium on Frontiers in Pulse-power-based High Energy Density Physics' held by National Institute for Fusion Science. The topics include the present status of high energy density plasma researches, extreme ultraviolet sources, intense radiation sources, high power ion beams, and R and D of related pulse power technologies. The 13 of the presented papers are indexed individually. (J.P.N.)

  12. Frontiers of particle beam and high energy density plasma science using pulse power technology

    International Nuclear Information System (INIS)

    Masugata, Katsumi

    2011-04-01

    The papers presented at the symposium on “Frontiers of Particle Beam and High Energy Density Plasma Science using Pulse Power Technology” held in November 20-21, 2009 at National Institute for Fusion Science are collected. The papers reflect the present status and resent progress in the experiment and theoretical works on high power particle beams and high energy density plasmas produced by pulsed power technology. (author)

  13. Energy losses estimation during pulsed-laser seam welding

    Czech Academy of Sciences Publication Activity Database

    Šebestová, Hana; Havelková, M.; Chmelíčková, H.

    2014-01-01

    Roč. 45, č. 3 (2014), s. 1116-1121 ISSN 1073-5615 R&D Projects: GA MŠk(CZ) LG13007 Institutional support: RVO:68378271 Keywords : laser welding * pulsed-laser * Nd:YAG laser Subject RIV: JP - Industrial Processing Impact factor: 1.461, year: 2014

  14. Irradiation distribution diagrams and their use for estimating collectable energy

    International Nuclear Information System (INIS)

    Ronnelid, M.; Karlsson, B.

    1997-01-01

    A method for summarising annual or seasonal solar irradiation data in irradiation distribution diagrams, including both direct and diffuse irradiation, is outlined. The practical use of irradiation distribution diagrams is discussed in the paper. Examples are given for the calculation of collectable irradiation on flat plate collectors or trough-like concentrators like the compound parabolic concentrator (CPC), and for the calculation of overhang geometries for windows to prevent overheating of buildings. (author)

  15. Use of delayed gamma rays for active non-destructive assay of {sup 235}U irradiated by pulsed neutron source (plasma focus)

    Energy Technology Data Exchange (ETDEWEB)

    Andola, Sanjay; Niranjan, Ram [Applied Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Kaushik, T.C., E-mail: tckk@barc.gov.in [Applied Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Rout, R.K. [Applied Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Kumar, Ashwani; Paranjape, D.B.; Kumar, Pradeep; Tomar, B.S.; Ramakumar, K.L. [Radioanalytical Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Gupta, S.C. [Applied Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

    2014-07-01

    A pulsed neutron source based on plasma focus device has been used for active interrogation and assay of {sup 235}U by monitoring its delayed high energy γ-rays. The method involves irradiation of fissile material by thermal neutrons obtained after moderation of a burst of neutrons emitted upon fusion of deuterium in plasma focus (PF) device. The delayed gamma rays emitted from the fissile material as a consequence of induced fission were detected by a large volume sodium iodide (NaI(Tl)) detector. The detector is coupled to a data acquisition system of 2k input size with 2k ADC conversion gain. Counting was carried out in pulse height analysis mode for time integrated counts up to 100 s while the temporal profile of delayed gamma has been obtained by counting in multichannel scaling mode with dwell time of 50 ms. To avoid the effect of passive (natural) and active (from surrounding materials) backgrounds, counts have been acquired for gamma energy between 3 and 10 MeV. The lower limit of detection of {sup 235}U in the oxide samples with this set-up is estimated to be 14 mg.

  16. Effect of prepulse on fast electron lateral transport at the target surface irradiated by intense femtosecond laser pulses

    International Nuclear Information System (INIS)

    Lin, X. X.; Li, Y. T.; Liu, B. C.; Liu, F.; Du, F.; Wang, S. J.; Lu, X.; Chen, L. M.; Zhang, L.; Liu, X.; Wang, J.; Liu, F.; Liu, X. L.; Wang, Z. H.; Ma, J. L.; Wei, Z. Y.; Zhang, J.

    2010-01-01

    The effects of preplasma on lateral fast electron transport at front target surface, irradiated by ultraintense (>10 18 W/cm 2 ) laser pulses, are investigated by Kα imaging technique. A large annular Kα halo with a diameter of ∼560 μm surrounding a central spot is observed. A specially designed steplike target is used to identify the possible mechanisms. It is believed that the halos are mainly generated by the lateral diffusion of fast electrons due to the electrostatic and magnetic fields in the preplasma. This is illustrated by simulated electron trajectories using a numerical model.

  17. Note: A well-confined pulsed low-energy ion beam: Test experiments of Ar+

    Science.gov (United States)

    Hu, Jie; Wu, Chun-Xiao; Tian, Shan Xi

    2018-06-01

    Here we report a pulsed low-energy ion beam source for ion-molecule reaction study, in which the ions produced by the pulsed electron impact are confined well in the spatial size of each bunch. In contrast to the ion focusing method to reduce the transverse section of the beam, the longitudinal section in the translational direction is compressed by introducing a second pulse in the ion time-of-flight system. The test experiments for the low-energy argon ions are performed. The present beam source is ready for applications in the ion-molecule reaction dynamics experiments, in particular, in combination with the ion velocity map imaging technique.

  18. Research on Pulsed Jet Flow Control without External Energy in a Blade Cascade

    Directory of Open Access Journals (Sweden)

    Jie Chen

    2017-12-01

    Full Text Available To control the flow separation in the compressors, a novel pulsed jet concept without external energy injection is proposed. The new concept designs a slot in the middle of the blade and sets a micro device to switch the slot periodically. Such a structure is expected to generate a pulsed jet by the pressure difference between the pressure side and the suction side of the blade. In order to analyze the interaction between the pulsed jet and unsteady separated flow, our numerical and experimental study is based on a specific cascade (with a flow separation inside and a pulsed jet (one of the unsteady flow control method. The experimental and numerical results both show that when the frequency of pulsed jet is approximate to that of the separation vortex, then the control tends to be more effective. Based on the numerical simulations, the proper orthogonal decomposition (POD is then used to reveal the control mechanism, extracting the different time-space structures from the original field. The results with the aid of POD show that the pulsed jet can redistribute the kinetic energy of each mode, and strengthen or weaken certain modes, particularly, while the steady jet reduces the kinetic energy of high-order modes in whole. Also, pulsed jet with proper parameters can transfer the energy from higher modes to the first flow mode (averaged flow, which is due to the conversion of the spatial vortical structures and the time evolution of the modes.

  19. Characteristics of pulsed photo-stimulated luminescence and thermoluminescence for the identification of gamma irradiated poultry eggs

    International Nuclear Information System (INIS)

    Bhatti, I.A.; Kwon, J.-H.

    2006-01-01

    Pulsed photo-stimulated luminescence (PPSL) is a simple screening method that can be employed qualitatively at the spot for the detection of eggs treated with ionizing radiation. In spite of the variations in the results during storage, the eggs of ostrich, duck, hen and quail irradiated to doses of 0, 1, 2 and 3 kGy, most of the samples were correctly identified up to six months during storage after irradiation. Thermoluminescence (TL) technique was also tried by using eggshells in order to confirm the PPSL results. TL glow curves were recorded between the temperatures 50 to 400 degree C at the rate of 5 degree per second for all the control and irradiated samples. On the basis of integrated areas of first glow curves (TL1), the glow curve ratios (TL1/TL2) and the shapes of maxima of TL1, the irradiation treatment of all the eggs was confirmed. Furthermore, the presence of calcite and aragonite minerals that cause the TL signal in the eggshells were studied using X-ray diffraction spectrometry. (authors)

  20. Generation of polyyne and methylpolyyne molecules from toluene by intense femtosecond laser pulse irradiation

    International Nuclear Information System (INIS)

    Ramadhan, Ali; Wesolowski, Michal; Duley, Walter; Sanderson, Joseph; Wakabayashi, Tomonari; Shiromaru, Haruo; Fujino, Tatsuya; Kodama, Takeshi

    2015-01-01

    Hydrogen-capped and methyl-capped carbon chains (polyynes) have been generated by intense femtosecond laser irradiation of pure liquid toluene. UV-Vis and Raman spectroscopy were used to confirm the presence of polyynes in the irradiated samples, and high performance liquid chromatography (HPLC) was used to separate polyynes up to C 18 H 2 and HC 13 CH 3 . (paper)

  1. The influence of laser pulse duration and energy on ICP-MS signal intensity, elemental fractionation, and particle size distribution in NIR fs-LA-ICP-MS

    Science.gov (United States)

    Diwakar, Prasoon K.; Harilal, Sivanandan S.; LaHaye, Nicole L.; Hassanein, Ahmed; Kulkarni, Pramod

    2015-01-01

    Laser parameters, typically wavelength, pulse width, irradiance, repetition rate, and pulse energy, are critical parameters which influence the laser ablation process and thereby influence the LA-ICP-MS signal. In recent times, femtosecond laser ablation has gained popularity owing to the reduction in fractionation related issues and improved analytical performance which can provide matrix-independent sampling. The advantage offered by fs-LA is due to shorter pulse duration of the laser as compared to the phonon relaxation time and heat diffusion time. Hence the thermal effects are minimized in fs-LA. Recently, fs-LA-ICP-MS demonstrated improved analytical performance as compared to ns-LA-ICP-MS, but detailed mechanisms and processes are still not clearly understood. Improvement of fs-LA-ICP-MS over ns-LA-ICP-MS elucidates the importance of laser pulse duration and related effects on the ablation process. In this study, we have investigated the influence of laser pulse width (40 fs to 0.3 ns) and energy on LA-ICP-MS signal intensity and repeatability using a brass sample. Experiments were performed in single spot ablation mode as well as rastering ablation mode to monitor the Cu/Zn ratio. The recorded ICP-MS signal was correlated with total particle counts generated during laser ablation as well as particle size distribution. Our results show the importance of pulse width effects in the fs regime that becomes more pronounced when moving from femtosecond to picosecond and nanosecond regimes. PMID:26664120

  2. Flux and energy deposition distribution studies inside the irradiation room of the portuguese 60Co irradiation facility

    International Nuclear Information System (INIS)

    Portugal, Luis; Oliveira, Carlos

    2008-01-01

    Full text: In December 2003 the irradiator of the Portuguese 60 Co irradiation facility, UTR, was replenished. Eighteen new sources were loaded and the older ones (156) were rearranged. The result was an irradiator with about 10.2 P Bq of total activity. The active area of the irradiator has also increased. Now it uses twenty five of the thirty tubes of the source rack, nine more than in the previous geometry. This facility was designed mainly for sterilisation of medical devices. However it is also used for the irradiation of other products such as cork stoppers, plastics and a limited number of food and feed. The purpose of this work is to perform dosimetric studies inside the irradiation room of a 60 Co irradiation facility, particularly, the flux and energy deposition distributions. The MCNPX code was used for the simulation of the facility. The track average mesh tally capabilities of MCNPX were used to plot the photon flux and energy deposition distributions. This tool provides a fast way for flux and energy deposition mapping. The absorbed dose distribution near the walls of the irradiation room was also calculated. Instead of using meshtallys as before, the average absorbed dose inside boxes lined with the walls was determined and afterwards a plot of its distribution was made. The absorbed dose rates obtained ranged from 5 to 500 Gy.h -1 depending on material being irradiated in process and the location on the wall. These positions can be useful for fixed irradiation purposes. Both dosimetric studies were done considering two different materials being irradiated in the process: cork stoppers and water, materials with quite different densities (0.102 and 1 g.cm-3, respectively). These studies showed some important characteristics of the radiation fields inside the irradiation room, namely its spatial heterogeneity. Tunnelling and shadow effects were enhanced when the product boxes increases its density. Besides a deeper dosimetric understanding of the

  3. Bragg Grating Inscription With Low Pulse Energy in Doped Microstructured Polymer Optical Fibers

    DEFF Research Database (Denmark)

    Min, Rui; Ortega, Beatriz; Nielsen, Kristian

    2018-01-01

    in the POFs without high pulse energy (mJ level) at 248-nm wavelength, which reduces maintenance costs. Furthermore, we can consider it as a solution to increase the lifetime of the laser system without high energy still allowing fast and efficient production of the FBGs for sensing applications.......We demonstrate that fiber Bragg gratings (FBGs) can be written in a doped polymer optical fiber (POF) in a low ultraviolet (UV) pulse energy regime (60Jpulse) using a 248-nm krypton fluoride excimer laser system. The total energy density per inscription necessary to obtain Bragg gratings is between...

  4. Effect of pulsed dose in simultaneous and sequential irradiation of V-79 cells by 14.8-MeV neutrons and 60Co photons

    International Nuclear Information System (INIS)

    Higgins, P.D.; DeLuca, P.M. Jr.; Gould, M.N.

    1984-01-01

    The effect of irradiating V-79 Chinese hamster cells with a mixture of 40% 14.8-MeV neutrons and 60% 69 Co photons with simultaneous or sequential exposures is investigated. Sample doses are obtained by irradiating cells with alternating 3-min pulses of neutrons and photons (in the sequential case) or with mixed neutrons and photons followed by equal beam-off periods to ensure equal total exposure times for sequential and simultaneous irradiations. Differences between the survival results under each beam configuration that are consistent with previous observations with nonpulsed irradiations are observed

  5. Formation of hexagonal silicon carbide by high energy ion beam irradiation on Si (1 0 0) substrate

    International Nuclear Information System (INIS)

    Bhuyan, H; Favre, M; Valderrama, E; Avaria, G; Chuaqui, H; Mitchell, I; Wyndham, E; Saavedra, R; Paulraj, M

    2007-01-01

    We report the investigation of high energy ion beam irradiation on Si (1 0 0) substrates at room temperature using a low energy plasma focus (PF) device operating in methane gas. The unexposed and ion exposed substrates were characterized by x-ray diffraction, scanning electron microscopy (SEM), photothermal beam deflection, energy-dispersive x-ray analysis and atomic force microscopy (AFM) and the results are reported. The interaction of the pulsed PF ion beams, with characteristic energy in the 60-450 keV range, with the Si surface, results in the formation of a surface layer of hexagonal silicon carbide. The SEM and AFM analyses indicate clear step bunching on the silicon carbide surface with an average step height of 50 nm and a terrace width of 800 nm

  6. Disinfection of wastewaters: high-energy electron vs gamma irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Farooq, S [King Fahd Univ. of Petroleum and Minerals, Dhahran (Saudi Arabia). Dept. of Civil Engineering; Kurucz, C N; Waite, T D [Miami Univ., Coral Gables, FL (United States); Cooper, W J [Florida International Univ., Miami, FL (United States). Drinking Water Research Center

    1993-07-01

    A study was undertaken to examine the sensitivity of a wastewater population of coliphage, total coliforms and total flora present in raw sewage and secondary effluent after irradiating with similar doses delivered by a high-energy electron beam and [gamma]-radiation. The electron beam study was conducted on a large scale at the Virginia Key Wastewater Treatment Plant, Miami, Florida. The facility is equipped with a 1.5 MeV, 50 mA electron accelerator, with a wastewater flow rate of 8ls[sup -1]. Concurrent [gamma]-radiation studies were conducted at laboratory scale using a 5000 Ci, [sup 60]Co [gamma]-source. Three logs reduction of all three test organisms were observed at an electron beam dose of 500 krads, while at least four logs reduction were observed at the same dose utilizing the [gamma]'source. (Author).

  7. High-energy neutron irradiation of superconducting compounds

    International Nuclear Information System (INIS)

    Sweedler, A.R.; Snead, C.L.; Newkirk, L.; Valencia, F.; Geballe, T.H.; Schwall, R.H.; Matthias, B.T.; Corenswit, E.

    1975-01-01

    The effect of high-energy neutron irradiation (E greater than 1 MeV) at ambient reactor temperatures on the superconducting properties of a variety of superconducting compounds is reported. The materials studied include the A-15 compounds Nb 3 Sn, Nb 3 Al, Nb 3 Ga, Nb 3 Ge and V 3 Si, the C-15 Laves phase HfV 2 , the ternary molybdenum sulfide Mo 3 Pb 0 . 5 S 4 and the layered dichalcogenide NbSe 2 . The superconducting transition temperature has been measured for all of the above materials for neutron fluences up to 5 x 10 19 n/cm 2 . The critical current for multifilamentary Nb 3 Sn has also been determined for fields up to 16 T and fluences between 3 x 10 17 n/cm 2 and 1.1 x 10 19 n/cm 2

  8. Roll-to-roll-compatible, flexible, transparent electrodes based on self-nanoembedded Cu nanowires using intense pulsed light irradiation

    Science.gov (United States)

    Zhong, Zhaoyang; Woo, Kyoohee; Kim, Inhyuk; Hwang, Hyewon; Kwon, Sin; Choi, Young-Man; Lee, Youngu; Lee, Taik-Min; Kim, Kwangyoung; Moon, Jooho

    2016-04-01

    Copper nanowire (Cu NW)-based flexible transparent conductive electrodes (FTCEs) have been investigated in detail for use in various applications such as flexible touch screens, organic photovoltaics and organic light-emitting diodes. In this study, hexadecylamine (HDA) adsorbed onto the surface of NWs is changed into polyvinylpyrrolidone (PVP) via a ligand exchange process; the high-molecular-weight PVP enables high dispersion stability. Intense pulsed light (IPL) irradiation is used to remove organic species present on the surface of the NWs and to form direct connections between the NWs rapidly without any atmospheric control. NWs are self-nanoembedded into a plastic substrate after IPL irradiation, which results in a smooth surface, strong NW/substrate adhesion, excellent mechanical flexibility and enhanced oxidation stability. Moreover, Cu NW FTCEs with high uniformities are successfully fabricated on a large area (150 mm × 200 mm) via successive IPL irradiation that is synchronized with the motion of the sample stage. This study demonstrates the possibility of roll-to-roll-based, large-scale production of low-cost, high-performance Cu NW-based FTCEs.Copper nanowire (Cu NW)-based flexible transparent conductive electrodes (FTCEs) have been investigated in detail for use in various applications such as flexible touch screens, organic photovoltaics and organic light-emitting diodes. In this study, hexadecylamine (HDA) adsorbed onto the surface of NWs is changed into polyvinylpyrrolidone (PVP) via a ligand exchange process; the high-molecular-weight PVP enables high dispersion stability. Intense pulsed light (IPL) irradiation is used to remove organic species present on the surface of the NWs and to form direct connections between the NWs rapidly without any atmospheric control. NWs are self-nanoembedded into a plastic substrate after IPL irradiation, which results in a smooth surface, strong NW/substrate adhesion, excellent mechanical flexibility and enhanced

  9. Design of extraction system on grid of plasma generator electrode for pulsed electron irradiator

    International Nuclear Information System (INIS)

    Agus Purwadi; Bambang Siswanto; Lely Susita RM; Suprapto; Anjar Anggraini H; Ihwanul Azis

    2016-01-01

    It has been carried out design and study of electron extraction particularly for obtaining the electron extraction current via grid on the Plasma Generator Chamber (PGC) caused by the existence of extraction voltage U_a. Electrons of plasma surface emitted to acceleration region through emission window and then extracted acceleration by extraction voltage U_a through foil window to atmospheric region for being applied to any target. Applied extraction voltage U_a on PEI device influences the forming and energy value of electron extraction current I_e then the PGC dimension influences the product of thermal electron emission current I_e_0. It has been determinated the PGC geometry and dimension of producing electron extraction current based on arc discharge plasma current to desire on any plasma density. From the calculation yield for the value of plasma density n_e = 78 x 10"1"0 cm"-"3 and the arc discharge current Id = 80 A (pulse width τ = 100µs) used the PGC size of (80 x 20 x 40) cm"3. Emission window area of (65 x 15) cm"2 located on the low part surface of PGC is covered by a grid sheet made of stainless steel of rectangular shape and the distance of one grid hole to another is 0,25 mm each others. Current value of I_e beside depends on plasma parameters also depends on the size of grid holes. The optimum of geometry and size is rectangular with its side size of p ≈ 0,50 mm with the plasma parameters optimum (density value n_e = 10"1"6 m"-"3 and electron temperature T_e = 6 eV). From the initial experiment yields obtained that the electron extraction efficiency value α = 37,25 % on extraction voltage V = 3 kV. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Fukuda, Makoto, E-mail: makoto.fukuda@qse.tohoku.ac.jp [Tohoku University, Sendai, 980-8579 (Japan); Kiran Kumar, N.A.P.; Koyanagi, Takaaki; Garrison, Lauren M. [Oak Ridge National Laboratory, Oak Ridge, TN, 37831 (United States); Snead, Lance L. [Massachusetts Institute of Technology, Cambridge, MA, 02139 (United States); Katoh, Yutai [Oak Ridge National Laboratory, Oak Ridge, TN, 37831 (United States); Hasegawa, Akira [Tohoku University, Sendai, 980-8579 (Japan)

    2016-10-15

    Neutron irradiation to single crystal pure tungsten was performed in the mixed spectrum High Flux Isotope Reactor (HFIR). To investigate the influences of neutron energy spectrum, the microstructure and irradiation hardening were compared with previous data obtained from the irradiation campaigns in the mixed spectrum Japan Material Testing Reactor (JMTR) and the sodium-cooled fast reactor Joyo. The irradiation temperatures were in the range of ∼90–∼800 °C and fast neutron fluences were 0.02–9.00 × 10{sup 25} n/m{sup 2} (E > 0.1 MeV). Post irradiation evaluation included Vickers hardness measurements and transmission electron microscopy. The hardness and microstructure changes exhibited a clear dependence on the neutron energy spectrum. The hardness appeared to increase with increasing thermal neutron flux when fast fluence exceeds 1 × 10{sup 25} n/m{sup 2} (E > 0.1 MeV). Irradiation induced precipitates considered to be χ- and σ-phases were observed in samples irradiated to >1 × 10{sup 25} n/m{sup 2} (E > 0.1 MeV), which were pronounced at high dose and due to the very high thermal neutron flux of HFIR. Although the irradiation hardening mainly caused by defects clusters in a low dose regime, the transmutation-induced precipitation appeared to impose additional significant hardening of the tungsten. - Highlights: • The microstructure and irradiation hardening of single crystal pure W irradiated in HFIR was investigated. • The neutron energy spectrum influence was evaluated by comparing the HFIR results with previous work in Joyo and JMTR. • In the dose range up to ∼1 dpa, the neutron energy spectrum influence of irradiation hardening was not clear. • In the dose range above 1 dpa, the neutron energy influence on irradiation hardening and microstructural development was clearly observed. • The irradiation induced precipitates caused significant irradiation hardening of pure W irradiated in HFIR.

  11. Argon defect complexes in low energy Ar irradiated molybdenum

    International Nuclear Information System (INIS)

    Veen, A. van; Buters, W.T.M.; Kolk, G.J. van der; Caspers, L.M.; Armstrong, T.R.

    1982-01-01

    Thermal desorption spectrometry has been used to study the defects created in Mo irradiated along the direction with Ar ions ranging in energy from 0.1 to 2 keV. In addition to monitoring the release of the implanted Ar, additional information has been obtained by decoration of the defects with low energy helium and subsequent monitoring of the helium release. The studies show evidence that the Ar can be trapped in both substitutional sites and in a configuration in which the Ar is associated with vacancies (ArVsub(n), n >= 2). Most of the Ar implanted at high energy is released at approx. equal to 1500 K by thermal vacancy assisted diffusion. Argon trapped closer to the surface is released at lower temperatures via at least three different surface related release mechanisms. Additional results are presented on the interaction of self interstitial atoms (introduced by 100 eV Xe bombardment) with the Ar defects. Substitutional Ar is found to convert to interstitial Ar which seems to be mobile at room temperature. The Ar-vacancy complexes are found to be reduced to substitutional Ar. The results of atomistic calculations of the release mechanisms will also be presented. (orig.)

  12. Formation of nanoparticles from thin silver films irradiated by laser pulses in air

    Science.gov (United States)

    Nastulyavichus, A. A.; Smirnov, N. A.; Kudryashov, S. I.; Ionin, A. A.; Saraeva, I. N.; Busleev, N. I.; Rudenko, A. A.; Khmel'nitskii, R. A.; Zayarnyi, D. A.

    2018-03-01

    Some specific features of the transport of silver nanoparticles onto a SiO2 substrate under focused nanosecond IR laser pulses is experimentally investigated. A possibility of obtaining silver coatings is demonstrated. The formation of silver nanostructures as a result of pulsed laser ablation in air is studied. Nanoparticles are formed by exposing a silver film to radiation of an HTF MARK (Bulat) laser marker (λ = 1064 nm). The thus prepared nanoparticles are analysed using scanning electron microscopy and optical spectroscopy.

  13. Repetitively pulsed, high energy KrF lasers for inertial fusion energy

    International Nuclear Information System (INIS)

    Myers, M.C.; Sethian, J.D.; Giuliani, J.L.; Lehmberg, R.; Kepple, P.; Wolford, M.F.; Hegeler, F.; Friedman, M.; Jones, T.C.; Swanekamp, S.B.; Weidenheimer, D.; Rose, D.

    2004-01-01

    Krypton fluoride (KrF) lasers produce highly uniform beams at 248 nm, allow the capability of 'zooming' the spot size to follow an imploding pellet, naturally assume a modular architecture and have been developed into a pulsed-power- based industrial technology that readily scales to a fusion power plant sized system. There are two main challenges for the fusion power plant application: to develop a system with an overall efficiency of greater than 6% (based on target gains of 100) and to achieve a durability of greater than 3 x 10 8 shots (two years at 5 Hz). These two issues are being addressed with the Electra (700 J, 5 Hz) and Nike (3000 J, single shot) KrF lasers at the Naval Research Laboratory. Based on recent advances in pulsed power, electron beam generation and transport, hibachi (foil support structure) design and KrF physics, wall plug efficiencies of greater than 7% should be achievable. Moreover, recent experiments show that it may be possible to realize long lived electron beam diodes using ceramic honeycomb cathodes and anode foils that are convectively cooled by periodically deflecting the laser gas. This paper is a summary of the progress in the development of the critical KrF technologies for laser fusion energy. (author)

  14. Agglomeration of amorphous silicon film with high energy density excimer laser irradiation

    International Nuclear Information System (INIS)

    He Ming; Ishihara, Ryoichi; Metselaar, Wim; Beenakker, Kees

    2007-01-01

    In this paper, agglomeration phenomena of amorphous Si (α-Si) films due to high energy density excimer laser irradiation are systematically investigated. The agglomeration, which creates holes or breaks the continuous Si film up into spherical beads, is a type of serious damage. Therefore, it determines an upper energy limit for excimer laser crystallization. It is speculated that the agglomeration is caused by the boiling of molten Si. During this process, outbursts of heterogeneously nucleated vapor bubbles are promoted by the poor wetting property of molten silicon on the SiO 2 layer underneath. The onset of the agglomeration is defined by extrapolating the hole density as a function of the energy density of the laser pulse. A SiO 2 capping layer (CL) is introduced on top of the α-Si film to investigate its influence on the agglomeration. It is found that effects of the CL depend on its thickness. The CL with a thickness less than 300 nm can be used to suppress the agglomeration. A thin CL acts as a confining layer and puts a constraint on bubble burst, and hence suppresses the agglomeration

  15. Epidermal protection with cryogen spray cooling during high fluence pulsed dye laser irradiation: an ex vivo study.

    Science.gov (United States)

    Tunnell, J W; Nelson, J S; Torres, J H; Anvari, B

    2000-01-01

    Higher laser fluences than currently used in therapy (5-10 J/cm(2)) are expected to result in more effective treatment of port wine stain (PWS) birthmarks. However, higher incident fluences increase the risk of epidermal damage caused by absorption of light by melanin. Cryogen spray cooling offers an effective method to reduce epidermal injury during laser irradiation. The objective of this study was to determine whether high laser incident fluences (15-30 J/cm(2)) could be used while still protecting the epidermis in ex vivo human skin samples. Non-PWS skin from a human cadaver was irradiated with a Candela ScleroPlus Laser (lambda = 585 nm; pulse duration = 1.5 msec) by using various incident fluences (8-30 J/cm(2)) without and with cryogen spray cooling (refrigerant R-134a; spurt durations: 40-250 msec). Assessment of epidermal damage was based on histologic analysis. Relatively short spurt durations (40-100 msec) protected the epidermis for laser incident fluences comparable to current therapeutic levels (8-10 J/cm(2)). However, longer spurt durations (100-250 msec) increased the fluence threshold for epidermal damage by a factor of three (up to 30 J/cm(2)) in these ex vivo samples. Results of this ex vivo study show that epidermal protection from high laser incident fluences can be achieved by increasing the cryogen spurt duration immediately before pulsed laser exposure. Copyright 2000 Wiley-Liss, Inc.

  16. Comparison of therapeutic effects between pulsed and continuous wave 810-nm wavelength laser irradiation for traumatic brain injury in mice.

    Directory of Open Access Journals (Sweden)

    Takahiro Ando

    Full Text Available Transcranial low-level laser therapy (LLLT using near-infrared light can efficiently penetrate through the scalp and skull and could allow non-invasive treatment for traumatic brain injury (TBI. In the present study, we compared the therapeutic effect using 810-nm wavelength laser light in continuous and pulsed wave modes in a mouse model of TBI.TBI was induced by a controlled cortical-impact device and 4-hours post-TBI 1-group received a sham treatment and 3-groups received a single exposure to transcranial LLLT, either continuous wave or pulsed at 10-Hz or 100-Hz with a 50% duty cycle. An 810-nm Ga-Al-As diode laser delivered a spot with diameter of 1-cm onto the injured head with a power density of 50-mW/cm(2 for 12-minutes giving a fluence of 36-J/cm(2. Neurological severity score (NSS and body weight were measured up to 4 weeks. Mice were sacrificed at 2, 15 and 28 days post-TBI and the lesion size was histologically analyzed. The quantity of ATP production in the brain tissue was determined immediately after laser irradiation. We examined the role of LLLT on the psychological state of the mice at 1 day and 4 weeks after TBI using tail suspension test and forced swim test.The 810-nm laser pulsed at 10-Hz was the most effective judged by improvement in NSS and body weight although the other laser regimens were also effective. The brain lesion volume of mice treated with 10-Hz pulsed-laser irradiation was significantly lower than control group at 15-days and 4-weeks post-TBI. Moreover, we found an antidepressant effect of LLLT at 4-weeks as shown by forced swim and tail suspension tests.The therapeutic effect of LLLT for TBI with an 810-nm laser was more effective at 10-Hz pulse frequency than at CW and 100-Hz. This finding may provide a new insight into biological mechanisms of LLLT.

  17. Chemical composition of dome-shaped structures grown on titanium by multi-pulse Nd:YAG laser irradiation

    International Nuclear Information System (INIS)

    Gyoergy, E.; Perez del Pino, A.; Serra, P.; Morenza, J.L.

    2004-01-01

    The specific dome-shaped structures were grown by multi-pulse Nd:YAG (λ=1.064 μm, τ=∼300 ns, and ν=30 kHz) laser irradiation of titanium targets in air at atmospheric pressure. The laser intensity values were chosen below the single-laser-pulse melting threshold of titanium. The chemical composition of the structures was studied as a function of laser pulse number as well as laser intensity, both at the outer surface layer and in depth. Micro-Raman spectroscopy, Auger electron spectroscopy (AES), and wavelength dispersive X-ray spectroscopy (WDX) were used as diagnostic techniques. Morphological investigations were performed by scanning electron microscopy. The obtained results revealed a lower oxygen concentration in the centre of the structures as compared to the borders and a lower concentration on the surface than in the depth. Moreover, it was found that the stoichiometry of the formed TiO 2-x oxides increases from the structures centre towards the border and from the surface towards the depth

  18. Silicon passivation study under low energy electron irradiation conditions

    International Nuclear Information System (INIS)

    Cluzel, R.

    2010-01-01

    Backside illuminated thinned CMOS (Complementary Metal Oxide Semiconductor) imaging system is a technology developed to increase the signal to noise ratio and the sensibility of such sensors. This configuration is adapted to the electrons detection from the energy range of [1 - 12 keV]. The impinging electron creates by multiplication several hundreds of secondary electrons close to the surface. A P ++ highly-doped passivation layer of the rear face is required to reduce the secondary electron surface recombination rate. Thanks to the potential barrier induced by the P ++ layer, the passivation layer increases the collected charges number and so the sensor collection gain. The goal of this study is to develop some experimental methods in order to determine the effect of six different passivation processes on the collection gain. Beforehand, the energy profile deposited by an incident electron is studied with the combination of Monte-Carlo simulations and some analytical calculations. The final collection gain model shows that the mirror effect from the passivation layer is a key factor at high energies whereas the passivation layer has to be as thin as possible at low energies. A first experimental setup which consists in irradiating P ++ /N large diodes allows to study the passivation process impacts on the surface recombinations. Thanks to a second setup based on a single event upset directly on thinned CMOS sensor, passivation techniques are discriminated in term of mirror effect and the implied spreading charges. The doping atoms activation laser annealing is turn out to be a multiplication gain inhomogeneity source impacting directly the matrix uniformity. (author)

  19. Determination of pulse energy dependence for skin denaturation from 585nm fibre laser

    Science.gov (United States)

    Mujica-Ascencio, S.; Velazquez-Gonzalez, J. S.; Mujica-Ascencio, C.; Alvarez-Chavez, J. A.

    2014-05-01

    In this paper, simulation and mathematical analysis for the determination of pulse energy from a Q-switched Yb3+-doped fibre laser is required in Port Wine Stain (PWS) treatment. The pulse energy depends on average power, gain, volume, repetition rate and pulse duration. In some treatments such as Selective Photothermolysis (SP), the peak power at the end of the optical fibre and pulse duration can be obtained and modified via a cavity design. For that purpose, a 585nm optical fibre laser full design which considers all of the above besides the average losses through the optical devices proposed for the design and the Ytterbium optical fibre overall gain will be presented.

  20. Proposals of electronic-vibrational energy relaxation studies by using laser pulses synchronized with IR-SR pulses

    International Nuclear Information System (INIS)

    Nakagawa, Hideyuki

    2000-01-01

    Synchrotron radiation is expected to be the sharp infrared light source for the advanced experiments on IR and FIR spectroscopy in wide research fields. Especially, synchronized use of SR with VIS and/or UV laser light is to be a promising technique for the research on the dynamical properties of the photo-excited states in condensed materials. Some proposals are attempted for high resolution IR spectroscopy to elucidate fine interaction of molecular ions in crystalline solids with their environmental field and for time-resolved IR spectroscopic studies on the electronic and vibrational energy relaxation by using laser pulses synchronized with IR-SR pulses. Several experimental results are presented in relevance to the subjects; on high-resolution FTIR spectra of cyanide ions and metal cyanide complexes in cadmium halide crystals, on the energy up-conversion process among the vibrational levels of cyanide ions in alkali halide crystals, and on the electronic-to-vibrational energy conversion process in metal cyanide complexes. (author)

  1. Primary power supply of repetitive pulsed intense current accelerator charged by capacitance of energy store

    International Nuclear Information System (INIS)

    Chen Jun; Yang Jianhua; Shu Ting; Zhang Jiande; Zhou Xiang; Wen Jianchun

    2008-01-01

    The primary power supply of repetitive pulsed intense current accelerator charged by capacitance of energy store is studied. The principle of primary power supply circuit and its time diagram of switches are presented. The circuit is analyzed and some expressions are got, especially, the usable voltage scope of capacitance of energy store, and the correlation between the parameters of circuit and time delay, which is between the turn-on of the charging circuit of capacitance of energy store and the circuit of recuperation. The time delay of 256 x 256 lookup table is made with the instruction of theory and the simulation of the actual parameters of circuits. The table is used by the control program to control the repetitive operating of the actual pulsed intense current accelerator. Finally, some conclusions of the primary power supply of repetitive pulsed intense current accelerator charged by capacitance of energy store are got. (authors)

  2. A Study of Polycrystalline Silicon Damage Features Based on Nanosecond Pulse Laser Irradiation with Different Wavelength Effects.

    Science.gov (United States)

    Xu, Jiangmin; Chen, Chao; Zhang, Tengfei; Han, Zhenchun

    2017-03-03

    Based on PVDF (piezoelectric sensing techniques), this paper attempts to study the propagation law of shock waves in brittle materials during the process of three-wavelength laser irradiation of polysilicon, and discusses the formation mechanism of thermal shock failure. The experimental results show that the vapor pressure effect and the plasma pressure effect in the process of pulsed laser irradiation lead to the splashing of high temperature and high density melt. With the decrease of the laser wavelength, the laser breakdown threshold decreases and the shock wave is weakened. Because of the pressure effect of the laser shock, the brittle fracture zone is at the edge of the irradiated area. The surface tension gradient and surface shear wave caused by the surface wave are the result of coherent coupling between optical and thermodynamics. The average propagation velocity of laser shock wave in polysilicon is 8.47 × 103 m/s, and the experiment has reached the conclusion that the laser shock wave pressure peak exponentially distributes attenuation in the polysilicon.

  3. A Study of Polycrystalline Silicon Damage Features Based on Nanosecond Pulse Laser Irradiation with Different Wavelength Effects

    Directory of Open Access Journals (Sweden)

    Jiangmin Xu

    2017-03-01

    Full Text Available Based on PVDF (piezoelectric sensing techniques, this paper attempts to study the propagation law of shock waves in brittle materials during the process of three-wavelength laser irradiation of polysilicon, and discusses the formation mechanism of thermal shock failure. The experimental results show that the vapor pressure effect and the plasma pressure effect in the process of pulsed laser irradiation lead to the splashing of high temperature and high density melt. With the decrease of the laser wavelength, the laser breakdown threshold decreases and the shock wave is weakened. Because of the pressure effect of the laser shock, the brittle fracture zone is at the edge of the irradiated area. The surface tension gradient and surface shear wave caused by the surface wave are the result of coherent coupling between optical and thermodynamics. The average propagation velocity of laser shock wave in polysilicon is 8.47 × 103 m/s, and the experiment has reached the conclusion that the laser shock wave pressure peak exponentially distributes attenuation in the polysilicon.

  4. Study of intense pulse irradiation effects on silicon targets considered as ground matter for optical detectors; Etude des effets d`irradiations pulsees intenses sur des cibles de silicium considere en tant que materiau de base pour detecteurs optiques

    Energy Technology Data Exchange (ETDEWEB)

    Muller, O

    1994-12-01

    This study aim was centered on morphological and structural alterations induced by laser irradiation on silicon targets considered as ground matter for optical detectors. First we recalled the main high light intensity effects on the condensed matter. Then we presented the experimental aspects. The experimental studies were achieved on two sample types: SiO{sub 2}/Si and Si. Two topics were studied: the defect chronology according to wavelength and pulse length, and the crystalline quality as well as the structure defects of irradiated zones by Raman spectroscopy. Finally, irradiation of Si targets by intense pulsed beams may lead to material fusion. This phenomenon is particularly easy when the material is absorbent, when the pulse is short and when the material is superficially oxidized. (MML). 204 refs., 93 figs., 21 tabs., 1 appendix.

  5. High-energy-density physics researches based on pulse power technology

    International Nuclear Information System (INIS)

    Horioka, Kazuhiko; Nakajima, Mitsuo; Kawamura, Tohru; Sasaki, Toru; Kondo, Kotaro; Yano, Yuuri

    2006-01-01

    Plasmas driven by pulse power device are of interest, concerning the researches on high-energy-density (HED) physics. Dense plasmas are produced using pulse power driven exploding discharges in water. Experimental results show that the wire plasma is tamped and stabilized by the surrounding water and it evolves through a strongly coupled plasma state. A shock-wave-heated, high temperature plasma is produced in a compact pulse power device. Experimental results show that strong shock waves can be produced in the device. In particular, at low initial pressure condition, the shock Mach number reaches 250 and this indicates that the shock heated region is dominated by radiation processes. (author)

  6. The use of logarithmic pulse height and energy scales in organic scintillator spectroscopy

    International Nuclear Information System (INIS)

    Whittlestone, S.

    1980-01-01

    The use of logarithmic pulse height and energy scales is advantageous for organic for organic scintillator neutron spectroscopy, providing an expanded dynamic range and economy of computer usage. An experimental logarithmic pulse height analysis system is shown to be feasible. A pulse height spectrum from a neutron measurement has been analysed using linear and logarithmic scales; the latter reduced the computer storage requirements by a factor of 13 and analysis time by 8.7, and there was no degradation of the analysed spectrum. Most of the arguments favouring use of logarithmic scales apply equally well to other types of scintillation spectroscopy. (orig.)

  7. Multistage plasma initiation process by pulsed CO2 laser irradiation of a Ti sample in an ambient gas (He, Ar, or N2)

    Science.gov (United States)

    Hermann, J.; Boulmer-Leborgne, C.; Mihailescu, I. N.; Dubreuil, B.

    1993-02-01

    New experimental results are reported on plasma initiation in front of a titanium sample irradiated by ir (λ=10.6 μm) laser pulses in an ambient gas (He, Ar, and N2) at pressures ranging from several Torr up to the atmosphere. The plasma is studied by space- and time-resolved emission spectroscopy, while sample vaporization is probed by laser-induced fluorescence spectroscopy. Threshold laser intensities leading to the formation of a plasma in the vapor and in the ambient gases are determined. Experimental results support the model of a vaporization mechanism for the plasma initiation (vaporization-initiated plasma breakdown). The plasma initiation is described by simple numerical criteria based on a two-stage process. Theoretical predictions are found to be in a reasonable agreement with the experiment. This study provides also a clear explanation of the influence of the ambient gas on the laser beam-metal surface energy transfer. Laser irradiation always causes an important vaporization when performed in He, while in the case of Ar or N2, the interaction is reduced in heating and vaporization of some surface defects and impurities.

  8. A simple irradiation facility for radiobiological experiments with low energy protons from a cyclotron

    International Nuclear Information System (INIS)

    Mukherjee, B.

    1982-01-01

    An experimental facility for irradiation of small biological targets with low-energy protons has been developed. The depth-dose distribution in soft-tissue is calculated from the proton energy spectrum. (orig.)

  9. Pulse-by-pulse energy measurement at the Stanford Linear Collider

    International Nuclear Information System (INIS)

    Blaylock, G.; Briggs, D.; Collins, B.; Petree, M.

    1992-01-01

    The stanford Linear Collider (SLC) collides a beam of electrons and positrons at 92 GeV. It is the first colliding linac, and produces Z 0 particles for High-Energy Physics measurements. The energy of each beam must be measured to one part in 10 4 on every collision (120 Hz). An Energy Spectrometer in each beam line after collision produces two stripes of high-energy synchrotron radiation with critical energy of a few MeV. The distance between these two stripes at an imaging plane measures the beam energy. The Wire- Imaging Synchrotron Radiation Detector (WISRD) system comprises a novel detector, data acquisition electronics, readout and analysis. The detector comprises an array of wires for each synchrotron stripe. The electronics measure secondary emission charge on each wire of each array. A Macintosh II (using THINK C, THINK Class Library) and DSP coprocessor (using ANSI C) acquire and analyze the data, and display and report the results for SLC operation

  10. Pulse-by-pulse energy measurement at the Stanford Linear Collider

    Science.gov (United States)

    Blaylock, G.; Briggs, D.; Collins, B.; Petree, M.

    1992-01-01

    The Stanford Linear Collider (SLC) collides a beam of electrons and positrons at 92 GeV. It is the first colliding linac, and produces Z(sup 0) particles for High-Energy Physics measurements. The energy of each beam must be measured to one part in 10(exp 4) on every collision (120 Hz). An Energy Spectrometer in each beam line after the collision produces two stripes of high-energy synchrotron radiation with critical energy of a few MeV. The distance between these two stripes at an imaging plane measures the beam energy. The Wire-Imaging Synchrotron Radiation Detector (WISRD) system comprises a novel detector, data acquisition electronics, readout, and analysis. The detector comprises an array of wires for each synchrotron stripe. The electronics measure secondary emission charge on each wire of each array. A Macintosh II (using THINK C, THINK Class Library) and DSP coprocessor (using ANSI C) acquire and analyze the data, and display and report the results for SLC operation.

  11. The energy spectrum of the 'runaway' electrons from a high voltage pulsed discharge

    International Nuclear Information System (INIS)

    Ruset, C.

    1985-01-01

    Some experimental results are presented on the influence of the pressure upon the energy spectrum of the runaway electrons generated into a pulsed high voltage argon discharge. These electrons enter a state of continuous acceleration between two collisions with rapidly increasing free path. The applied discharge current varies from 10 to 300 A, the pulse time is about 800 ns. Relativistic effects are taken into consideration. Theoretical explanation is based on the pnenomenon of electron spreading on plasma oscillations. (D.Gy.)

  12. The Space-, Time-, and Energy-distribution of Neutrons from a Pulsed Plane Source

    Energy Technology Data Exchange (ETDEWEB)

    Claesson, Arne

    1962-05-15

    The space-, time- and energy-distribution of neutrons from a pulsed, plane, high energy source in an infinite medium is determined in a diffusion approximation. For simplicity the moderator is first assumed to be hydrogen gas but it is also shown that the method can be used for a moderator of arbitrary mass.

  13. Relaxation of ion energy spectrum just after turbulent heating pulse in TRIAM-1 tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Kazuo; Hiraki, Naoji; Nakamura, Yukio; Itoh, Satoshi [Kyushu Univ., Fukuoka (Japan). Research Inst. for Applied Mechanics

    1982-07-01

    The temporal evolution and spatial profile of the ion energy spectrum just after the application of a toroidal current pulse for turbulent heating are investigated experimentally in the TRIAM-1 tokamak and also numerically using the Fokker-Planck equation. The two-component ion energy spectrum formed by turbulent heating relaxes to a single one within tausub(i) (the ion collision time).

  14. Organelle-specific injury to melanin-containing cells in human skin by pulsed laser irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, G.F.; Shepard, R.S.; Paul, B.S.; Menkes, A.; Anderson, R.R.; Parrish, J.A.

    1983-12-01

    Physical models predict that ultraviolet laser radiation of appropriately brief pulses can selectively alter melanin-containing cellular targets in human skin. Skin of normal human volunteers was exposed to brief (20 nanosecond) 351-nm wave length pulses from a XeF excimer laser, predicting that those cells containing the greatest quantities of melanized melanosomes (lower half of the epidermis) would be selectively damaged. Transmission electron microscopy revealed the earliest cellular alteration to be immediate disruption of melanosomes, both within melanocytes and basal keratinocytes. This disruption was dose dependent and culminated in striking degenerative changes in these cells. Superficial keratinocytes and Langerhans cells were not affected. It was concluded that the XeF excimer laser is capable of organelle-specific injury to melanosomes. These findings may have important clinical implications in the treatment of both benign and malignant pigmented lesions by laser radiations of defined wave lengths and pulse durations.

  15. Laser short-pulse heating of an aluminum thin film: Energy transfer in electron and lattice sub-systems

    Energy Technology Data Exchange (ETDEWEB)

    Bin Mansoor, Saad; Sami Yilbas, Bekir, E-mail: bsyilbas@kfupm.edu.sa

    2015-08-15

    Laser short-pulse heating of an aluminum thin film is considered and energy transfer in the film is formulated using the Boltzmann equation. Since the heating duration is short and the film thickness is considerably small, thermal separation of electron and lattice sub-systems is incorporated in the analysis. The electron–phonon coupling is used to formulate thermal communication of both sub-systems during the heating period. Equivalent equilibrium temperature is introduced to account for the average energy of all phonons around a local point when they redistribute adiabatically to an equilibrium state. Temperature predictions of the Boltzmann equation are compared with those obtained from the two-equation model. It is found that temperature predictions from the Boltzmann equation differ slightly from the two-equation model results. Temporal variation of equivalent equilibrium temperature does not follow the laser pulse intensity in the electron sub-system. The time occurrence of the peak equivalent equilibrium temperature differs for electron and lattice sub-systems, which is attributed to phonon scattering in the irradiated field in the lattice sub-system. In this case, time shift is observed for occurrence of the peak temperature in the lattice sub-system.

  16. Laser short-pulse heating of an aluminum thin film: Energy transfer in electron and lattice sub-systems

    International Nuclear Information System (INIS)

    Bin Mansoor, Saad; Sami Yilbas, Bekir

    2015-01-01

    Laser short-pulse heating of an aluminum thin film is considered and energy transfer in the film is formulated using the Boltzmann equation. Since the heating duration is short and the film thickness is considerably small, thermal separation of electron and lattice sub-systems is incorporated in the analysis. The electron–phonon coupling is used to formulate thermal communication of both sub-systems during the heating period. Equivalent equilibrium temperature is introduced to account for the average energy of all phonons around a local point when they redistribute adiabatically to an equilibrium state. Temperature predictions of the Boltzmann equation are compared with those obtained from the two-equation model. It is found that temperature predictions from the Boltzmann equation differ slightly from the two-equation model results. Temporal variation of equivalent equilibrium temperature does not follow the laser pulse intensity in the electron sub-system. The time occurrence of the peak equivalent equilibrium temperature differs for electron and lattice sub-systems, which is attributed to phonon scattering in the irradiated field in the lattice sub-system. In this case, time shift is observed for occurrence of the peak temperature in the lattice sub-system

  17. High Energy Density Dielectrics for Pulsed Power Applications

    National Research Council Canada - National Science Library

    Wu, Richard L; Bray, Kevin R

    2008-01-01

    This report was developed under a SBIR contract. Aluminum oxynitride (AlON) capacitors exhibit several promising characteristics for high energy density capacitor applications in extreme environments...

  18. LASER APPLICATIONS AND OTHER TOPICS IN QUANTUM ELECTRONICS: Dynamics of splashing of molten metals during irradiation with single CO2 laser pulses

    Science.gov (United States)

    Arutyunyan, R. V.; Baranov, V. Yu; Bol'shov, Leonid A.; Dolgov, V. A.; Malyuta, D. D.; Mezhevov, V. S.; Semak, V. V.

    1988-03-01

    An experimental investigation was made of the dynamics of the loss of the melt as a result of interaction with single-mode CO2 laser radiation pulses of 5-35 μs duration. The dynamics of splashing of the melt during irradiation with short pulses characterized by a Gaussian intensity distribution differed from that predicted by models in which the distribution of the vapor pressure was assumed to be radially homogeneous.

  19. Measuring radiation damage dynamics by pulsed ion beam irradiation: 2016 project annual report

    Energy Technology Data Exchange (ETDEWEB)

    Kucheyev, Sergei O. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-01-04

    The major goal of this project is to develop and demonstrate a novel experimental approach to access the dynamic regime of radiation damage formation in nuclear materials. In particular, the project exploits a pulsed-ion-beam method in order to gain insight into defect interaction dynamics by measuring effective defect interaction time constants and defect diffusion lengths. For Year 3, this project had the following two major milestones: (i) the demonstration of the measurement of thermally activated defect-interaction processes by pulsed ion beam techniques and (ii) the demonstration of alternative characterization techniques to study defect dynamics. As we describe below, both of these milestones have been met.

  20. The Effect of Varying Ultrafast Pulse Laser Energies on the Electrical Properties of Reduced Graphene Oxide Sheets in Solution

    Science.gov (United States)

    Ibrahim, Khaled H.; Irannejad, Mehrdad; Wales, Benjamin; Sanderson, Joseph; Musselman, Kevin P.; Yavuz, Mustafa

    2018-02-01

    Laser treatment of graphene oxide solution among other techniques is a well-established technique for producing reduced graphene sheets. However, production of high-quality ultra-low sheet resistance reduced graphene oxide (rGO) sheets in solution has been a challenge due to their high degree of randomness, defect-rich medium, and lack of controlability. Recent studies lack an in-depth analytic comparison of laser treatment parameters that yield the highest quality rGO sheets with a low defect ratio. Hence, in this study, we implement a comprehensive comparison of laser treatment parameters and their effect on the yielded rGO sheets from an electronic and physical standpoint. Ultra-low sheet resistance graphene oxide sheets were fabricated using ultrafast laser irradiation with different laser pulse energies in the range of 0.25-2 mJ. Laser treatment for 10 min using a pulse energy of 1 mJ resulted in an increase in the defect spacing, accompanied by a large red shift in the optical absorption of the C=C bond, indicating significant restoration of the s p 2 carbon bonds. These enhancements resulted in a significant reduction in the electrical resistance of the rGO flakes (up to 2 orders of magnitude), raising the electron mobility of the films produced using the irradiated graphene oxide a step closer to that of pristine graphene films. From this study, we can also deduce which exposure regimes result in the fabrication of quantum dots and continuous defect-free films.

  1. Formation of tin-tin oxide core–shell nanoparticles in the composite SnO{sub 2−x}/nitrogen-doped carbon nanotubes by pulsed ion beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Korusenko, P.M., E-mail: korusenko@obisp.oscsbras.ru [Omsk Scientific Center, Siberian Branch of the Russian Academy of Sciences, Karl Marx avenue 15, 644040 Omsk (Russian Federation); Nesov, S.N.; Bolotov, V.V.; Povoroznyuk, S.N. [Omsk Scientific Center, Siberian Branch of the Russian Academy of Sciences, Karl Marx avenue 15, 644040 Omsk (Russian Federation); Pushkarev, A.I. [National Research Tomsk Polytechnic University, Lenin Ave. 2a, 634028 Tomsk (Russian Federation); Ivlev, K.E. [Omsk Scientific Center, Siberian Branch of the Russian Academy of Sciences, Karl Marx avenue 15, 644040 Omsk (Russian Federation); Smirnov, D.A. [St. Petersburg State University, Lieutenant Shmidt Emb. 11, 198504 St. Petersburg (Russian Federation); Institute of Solid State Physics, Dresden University of Technology, D-01069 Dresden (Germany)

    2017-03-01

    Highlights: • Original method the formation of core–shell structures by pulsed ion beam is proposed. • The composite SnO{sub 2−x}/N-MWCNTs was irradiated by pulsed ion beam. • Morphology and electronic structure of the irradiated composite were characterized. • The formation of Sn−SnO{sub x} core–shell nanoparticles after irradiation was observed. - Abstract: The complex methods of transmission electron microscopy, energy dispersive X-ray analysis, and X-ray photoelectron spectroscopy were used to investigate the changes in the morphology, phase composition, and electronic structure of the composite SnO{sub 2−x}/nitrogen-doped multiwalled carbon nanotubes (SnO{sub 2−x}/N-MWCNTs) irradiated with the pulsed ion beam of nanosecond duration. The irradiation of the composite SnO{sub 2−x}/N-MWCNTs leads to the formation of nanoparticles with the core–shell structure on the surface of CNTs with a sharp interfacial boundary. It has been established that the “core” is a metal tin (Sn{sup 0}) with a typical size of 5–35 nm, and the “shell” is a thin amorphous layer (2–6 nm) consisting of nonstoichiometric tin oxide with a low oxygen content. The “core–shell” structure Sn−SnO{sub x} is formed due to the process of heating and evaporation of SnO{sub 2−x} under the effect of the ion beam, followed by vapor deposition on the surface of carbon nanotubes.

  2. Few-cycle high energy mid-infrared pulse from Ho:YLF laser

    International Nuclear Information System (INIS)

    Murari, Krishna

    2017-04-01

    Over the past decade, development of high-energy ultrafast laser sources has led to important breakthroughs in attoscience and strong-field physics study in atoms and molecules. Coherent pulse synthesis of few-cycle high-energy laser pulse is a promising tool to generate isolated attosecond pulses via high harmonics generation (HHG). An effective way to extend the HHG cut-off energy to higher values is making use of long mid-infrared (MIR) driver wavelength, as the ponderomotive potential scales quadratically with wavelength. If properly scaled in energy to multi-mJ level and few-cycle duration, such pulses provide a direct path to intriguing attoscience experiments in gases and solids, which even permit the realization of bright coherent table-top HHG sources in the water-window and keV X-ray region. However, the generation of high-intensity long-wavelength MIR pulses has always remained challenging, in particular starting from high-energy picosecond 2-μm laser driver, that is suitable for further energy scaling of the MIR pulses to multi-mJ energies by utilizing optical parametric amplifiers (OPAs). In this thesis, a front-end source for such MIR OPA is presented. In particular, a novel and robust strong-field few-cycle 2-μm laser driver directly from picosecond Ho:YLF laser and utilizing Kagome fiber based compression is presented. We achieved: a 70-fold compression of 140-μJ, 3.3-ps pulses from Ho:YLF amplifier to 48 fs with 11 μJ energy. The work presented in this thesis demonstrates a straightforward path towards generation of few-cycle MIR pulses and we believe that in the future the ultrafast community will benefit from this enabling technology. The results are summarized in mainly four parts: The first part is focused on the development of a 2-μm, high-energy laser source as the front-end. Comparison of available technology in general and promising gain media at MIR wavelength are discussed. Starting from the basics of an OPA, the design criteria

  3. Few-cycle high energy mid-infrared pulse from Ho:YLF laser

    Energy Technology Data Exchange (ETDEWEB)

    Murari, Krishna

    2017-04-15

    Over the past decade, development of high-energy ultrafast laser sources has led to important breakthroughs in attoscience and strong-field physics study in atoms and molecules. Coherent pulse synthesis of few-cycle high-energy laser pulse is a promising tool to generate isolated attosecond pulses via high harmonics generation (HHG). An effective way to extend the HHG cut-off energy to higher values is making use of long mid-infrared (MIR) driver wavelength, as the ponderomotive potential scales quadratically with wavelength. If properly scaled in energy to multi-mJ level and few-cycle duration, such pulses provide a direct path to intriguing attoscience experiments in gases and solids, which even permit the realization of bright coherent table-top HHG sources in the water-window and keV X-ray region. However, the generation of high-intensity long-wavelength MIR pulses has always remained challenging, in particular starting from high-energy picosecond 2-μm laser driver, that is suitable for further energy scaling of the MIR pulses to multi-mJ energies by utilizing optical parametric amplifiers (OPAs). In this thesis, a front-end source for such MIR OPA is presented. In particular, a novel and robust strong-field few-cycle 2-μm laser driver directly from picosecond Ho:YLF laser and utilizing Kagome fiber based compression is presented. We achieved: a 70-fold compression of 140-μJ, 3.3-ps pulses from Ho:YLF amplifier to 48 fs with 11 μJ energy. The work presented in this thesis demonstrates a straightforward path towards generation of few-cycle MIR pulses and we believe that in the future the ultrafast community will benefit from this enabling technology. The results are summarized in mainly four parts: The first part is focused on the development of a 2-μm, high-energy laser source as the front-end. Comparison of available technology in general and promising gain media at MIR wavelength are discussed. Starting from the basics of an OPA, the design criteria

  4. Stability of uranium silicides during high energy ion irradiation

    International Nuclear Information System (INIS)

    Birtcher, R.C; Wang, L.M.

    1991-11-01

    Changes induced by 1.5 MeV Kr ion irradiation of both U 3 Si and U 3 Si 2 have been followed by in situ transmission electron microscopy. When irradiated at sufficiently low temperatures, both alloys transform from the crystalline to the amorphous state. When irradiated at temperatures above the temperature limit for ion beam amorphization, both compounds disorder with the Martensite twin structure in U 3 Si disappearing from view in TEM. Prolonged irradiation of the disordered crystalline phases results in nucleation of small crystallites within the initially large crystal grains. The new crystallites increase in number during continued irradiation until a fine grain structure is formed. Electron diffraction yields a powder-like diffraction pattern that indicates a random alignment of the small crystallites. During a second irradiation at lower temperatures, the small crystallizes retard amorphization. After 2 dpa at high temperatures, the amorphization dose is increased by over twenty times compared to that of initially unirradiated material

  5. Note: A high-energy-density Tesla-type pulse generator with novel insulating oil

    Science.gov (United States)

    Liu, Sheng; Su, Jiancang; Fan, Xuliang

    2017-09-01

    A 10-GW high-energy-density Tesla-type pulse generator is developed with an improved insulating liquid based on a modified Tesla pulser—TPG700, of which the pulse forming line (PFL) is filled with novel insulating oil instead of transformer oil. Properties of insulating oil determining the stored energy density of the PFL are analyzed, and a criterion for appropriate oil is proposed. Midel 7131 is chosen as an application example. The results of insulating property experiment under tens-of-microsecond pulse charging demonstrate that the insulation capability of Midel 7131 is better than that of KI45X transformer oil. The application test in Tesla pulser TPG700 shows that the output power is increased to 10.5 GW with Midel 7131. The output energy density of TPG700 increases for about 60% with Midel 7131.

  6. Effect of gamma irradiation on sperm activity, sperm viability and adult competitiveness of the pulse beetle Collosobruchus Chinensis L

    International Nuclear Information System (INIS)

    Roushdy, H.M.; Ahmed, M.Y.Y.; Abdel-Nasr, A.E.; Abdel-Rahman, A.M.; Haiba, I.M.H.

    1984-01-01

    When mature pupae of callosobruchus chinensis L. were treated with 7 krad, the resulting adults were sterile. Replacing normal males by irradiate ones in the normal population, decreases the egg hatchability. Hatchability decreased from 88.23% in the 1st 3 days to 32.44% after replacing normal males by sterile ones (in the 2nd 3 days). Insemination by normal males could approximately nullify insemination by irradiated males, as the egg hatchability increased from zero to 37.79% even after replacing the irradiated males by normal ones. Percent egg infertility of the eggs produced from newly emerged virgin females mated with sterile males was 100%. When males irradiated (1) with 7 krad as fully grown pupae were confined with unirradiated (U) males and females (1:1:1 ratio), infertility of the resulting eggs were 44.98%. The competitiveness value of irradiated males was 0.54. Males and females both treated as fully grown pupae with a sterilizing dose (7 krad) and confined with U males and U females at a 1 male :1 female :U male : female ratio caused 55.77% infertility in the resulting eggs. When the ratio of sterile males and females was increased to 5:5:1:1 or 10:10:1:1, the infertility reached 91.27% and 100.0% respectively. The percentage of actual infertility was less than expected for the ratios 1:1:1:1 and 5:5:1:1, but it was exceeded with the highest ratio used (10:10:1:1). The competitiveness value for this flooding ratio was 1.00 i.e., the sterile adults were fully competitive with the normal ones. These results indicated that irradiation with 7 krad, a sterilizing dose, did not decrease sexual competitiveness of adults. Also, the release of 1 males together with 1 female could give good results in controlling a population of the pulse beetle in an autocidal control program; and therefore, separation of the sexes prior to release is probably unnecessary

  7. Improvement of Polytetrafluoroethylene Surface Energy by Repetitive Pulse Non-Thermal Plasma Treatment in Atmospheric Air

    International Nuclear Information System (INIS)

    Yang Guoqing; Zhang Guanjun; Zhang Wenyuan

    2011-01-01

    Improvement of polytetrafluoroethylene surface energy by non-thermal plasma treatment is presented, using a nanosecond-positive-edge repetitive pulsed dielectric barrier discharge generator in atmospheric air. The electrical parameters including discharging power, peak and density of micro-discharge current were calculated, and the electron energy was estimated. Surface treatment experiments of polytetrafluoroethylene films were conducted for both different applied voltages and different treating durations. Results show that the surface energy of polytetrafluoroethylene film could be improved to 40 mJ/m 2 or more by plasma treatment. Surface roughness measurement and surface X-ray photoelectron spectroscopy analysis indicate that there are chemical etching and implantation of polar oxygen groups in the sample surface treating process, resulting in the improvement of the sample surface energy. Compared with an AC source of 50 Hz, the dielectric barrier discharges generated by a repetitive pulsed source could provide higher peak power, lower mean power, larger micro-discharge current density and higher electron energy. Therefore, with the same applied peak voltage and treating duration, the improvement of polytetrafluoroethylene surface energy using repetitive pulsed plasma is more effective, and the plasma treatment process based on repetitive pulsed dielectric barrier discharges in air is thus feasible and applicable.

  8. Time gating for energy selection and scatter rejection: High-energy pulsed neutron imaging at LANSCE

    Science.gov (United States)

    Swift, Alicia; Schirato, Richard; McKigney, Edward; Hunter, James; Temple, Brian

    2015-09-01

    The Los Alamos Neutron Science Center (LANSCE) is a linear accelerator in Los Alamos, New Mexico that accelerates a proton beam to 800 MeV, which then produces spallation neutron beams. Flight path FP15R uses a tungsten target to generate neutrons of energy ranging from several hundred keV to ~600 MeV. The beam structure has micropulses of sub-ns width and period of 1.784 ns, and macropulses of 625 μs width and frequency of either 50 Hz or 100 Hz. This corresponds to 347 micropulses per macropulse, or 1.74 x 104 micropulses per second when operating at 50 Hz. Using a very fast, cooled ICCD camera (Princeton Instruments PI-Max 4), gated images of various objects were obtained on FP15R in January 2015. Objects imaged included blocks of lead and borated polyethylene; a tungsten sphere; and a tungsten, polyethylene, and steel cylinder. Images were obtained in 36 min or less, with some in as little as 6 min. This is novel because the gate widths (some as narrow as 10 ns) were selected to reject scatter and other signal not of interest (e.g. the gamma flash that precedes the neutron pulse), which has not been demonstrated at energies above 14 MeV. This proof-of-principle experiment shows that time gating is possible above 14MeV and is useful for selecting neutron energy and reducing scatter, thus forming clearer images. Future work (simulation and experimental) is being undertaken to improve camera shielding and system design and to precisely determine optical properties of the imaging system.

  9. Stabilizing laser energy density on a target during pulsed laser deposition of thin films

    Science.gov (United States)

    Dowden, Paul C.; Jia, Quanxi

    2016-05-31

    A process for stabilizing laser energy density on a target surface during pulsed laser deposition of thin films controls the focused laser spot on the target. The process involves imaging an image-aperture positioned in the beamline. This eliminates changes in the beam dimensions of the laser. A continuously variable attenuator located in between the output of the laser and the imaged image-aperture adjusts the energy to a desired level by running the laser in a "constant voltage" mode. The process provides reproducibility and controllability for deposition of electronic thin films by pulsed laser deposition.

  10. Microstructural and Wear Behavior Characterization of Porous Layers Produced by Pulsed Laser Irradiation in Glass-Ceramics Substrates.

    Science.gov (United States)

    Sola, Daniel; Conde, Ana; García, Iñaki; Gracia-Escosa, Elena; de Damborenea, Juan J; Peña, Jose I

    2013-09-09

    In this work, wear behavior and microstructural characterization of porous layers produced in glass-ceramic substrates by pulsed laser irradiation in the nanosecond range are studied under unidirectional sliding conditions against AISI316 and corundum counterbodies. Depending on the optical configuration of the laser beam and on the working parameters, the local temperature and pressure applied over the interaction zone can generate a porous glass-ceramic layer. Material transference from the ball to the porous glass-ceramic layer was observed in the wear tests carried out against the AISI316 ball counterface whereas, in the case of the corundum ball, the wear volume loss was concentrated in the porous layer. Wear rate and friction coefficient presented higher values than expected for dense glass-ceramics.

  11. Microstructural and Wear Behavior Characterization of Porous Layers Produced by Pulsed Laser Irradiation in Glass-Ceramics Substrates

    Directory of Open Access Journals (Sweden)

    Jose I. Peña

    2013-09-01

    Full Text Available In this work, wear behavior and microstructural characterization of porous layers produced in glass-ceramic substrates by pulsed laser irradiation in the nanosecond range are studied under unidirectional sliding conditions against AISI316 and corundum counterbodies. Depending on the optical configuration of the laser beam and on the working parameters, the local temperature and pressure applied over the interaction zone can generate a porous glass-ceramic layer. Material transference from the ball to the porous glass-ceramic layer was observed in the wear tests carried out against the AISI316 ball counterface whereas, in the case of the corundum ball, the wear volume loss was concentrated in the porous layer. Wear rate and friction coefficient presented higher values than expected for dense glass-ceramics.

  12. 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.

  13. Effect of pulsed dose in simultaneous and sequential irradiation of V-79 cells by 14.8 MeV neutrons and 60Co photons

    International Nuclear Information System (INIS)

    Higgins, P.D.; DeLuca, P.M. Jr.; Gould, M.N.; Schell, M.C.; Pearson, D.W.

    1983-01-01

    The effect of irradiating V-79 Chinese hamster ovary cells with a mixture of 40% 14.8-MeV neutrons and 60% 60 Co photons with simultaneous or sequential exposures is investigated. Target doses are obtained by irradiating cell samples with 3-minute-long pulses of alternating neutrons and photons (in the sequential case) or with mixed neutrons and photons followed by equal beam-off periods to insure equal total-exposure times for sequenced and simultaneous irradiations. We observe qualitative differences between the survival results under each beam configuration that confirms earlier observations

  14. Study of bond-energy variations in molecular systems under irradiation; Etude de la variation de l'energie de liaison dans les systemes moleculaires irradies

    Energy Technology Data Exchange (ETDEWEB)

    Naudet, G; Passe, S [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1968-07-01

    On the basis of experimental results selected from publications, the evolution of the bond energy of a molecular system under irradiation - leading to a more or less bound state - is studied. This variation of bond energy is then compared to the total bond energy of the initial system and to the energy absorbed in the system during the irradiation. This is done as a function of the nature of molecular system and the radiation spectrum and intensity. Our working method will first be explained, and the results obtained will then be given. (authors) [French] A l'aide de resultats experimentaux, selectionnes dans les publications, nous etudions l'evolution de l'energie de liaison d'un systeme moleculaire sous irradiation (evolution vers un etat plus ou moins lie), et nous comparons cette variation d'energie de liaison a l'energie totale de liaison du systeme initial et a l'energie absorbee dans le systeme au cours de l'irradiation. Ceci est fait en fonction de la nature du systeme moleculaire ainsi que du spectre et de l'intensite du rayonnement. Nous exposons d'abord notre methode de travail, puis les resultats obtenus. (auteurs)

  15. Simulation of pulsed accidental energy release in a reactor core

    International Nuclear Information System (INIS)

    Ryshanskii, V.A.; Ivanov, A.G.; Uskov, A.A.

    1995-01-01

    At the present time the strength of the load-bearing members of VVER and fast reactors during a hypothetical accident is ordinarily investigated in model experiments [1]. A power burst during an accident is simulated by a nonnuclear exothermal reaction in water, which simulates the coolant and fills the model. The problem is to make the correct choice of the simulator of the accidental energy burst as an effective (i.e., sufficiently high working capacity) source of dangerous loads, corresponding to the conditions of an accident. What factors and parameters determine the energy release? The answers to these questions are contradictory

  16. Texturing in titanium grade 2 surface irradiate with ultrashort pulse laser

    International Nuclear Information System (INIS)

    Nogueira, Alessandro Francelino

    2015-01-01

    The texturing laser micromachining is an important alternative to improve the bonding adhesion between composites and titanium, which are applied to structural components in the aerospace industry. The texturing running on titanium plates is due to the fact that the preferred joining technique for many composite materials is the adhesive bonding. In this work, titanium plates were texturized using laser ultrashort pulses temporal widths of femtoseconds. This process resulted in minimal heat transfer to the material, avoiding deformation of the titanium plate surface as well as the formation of resolidified material in the ablated region. These drawbacks have occurred with the use of nanoseconds pulses. Were performed three types of texturing using laser with femtosecond pulses, with variations in the distances between the machined lines. The analysis of the obtained surfaces found that the wettability increases when there is the increased distance between the texturing lines. Advancing in the analysis by optical profilometry of textured surfaces was observed that there is substantial increase in the volume available for penetration of structural adhesive when the distances between the textured lines are diminished. In tensile tests conducted it was observed that there is an increase in shear strength of the adhesive joint by reducing the distance between the textured lines. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Koyanagi, Takaaki, E-mail: koyanagit@ornl.gov [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Kumar, N.A.P. Kiran [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Hwang, Taehyun [Tohoku University, Sendai, 980-8579 (Japan); Garrison, Lauren M.; Hu, Xunxiang [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Snead, Lance L. [Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Katoh, Yutai [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

    2017-07-15

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

  18. Influence of high energy electron irradiation and gamma irradiation on the osmotic resistance of human erythrocyte membranes

    International Nuclear Information System (INIS)

    Catana, D.; Hategan, Alina; Moraru, Rodica; Popescu, Alina; Morariu, V. V.

    1998-01-01

    The effects of 5 MeV electrons and of gamma irradiation at 0 deg. C on the osmotic fragility of human erythrocyte membranes are presented. Both electron and gamma radiation in the range 0-400 Gy induced no hemolysis indicating that the membrane modifications due to radiation interaction do not reach a critical point as to cause swelling of the cells and subsequent lysis. The osmotic stress experiments performed after irradiation showed that the gamma irradiated erythrocytes exhibited an almost similar sigmoidal behavior for all irradiation doses, whereas the electron irradiated samples showed a much larger increase in hemolysis degree and, in the case of a given electron dose (100 Gy), the hemolysis was found much smaller than for the control sample (a similar behavior of the erythrocytes was found in the case of microwave irradiation at temperatures under 0 deg. C). Our experimental data suggest that electron radiation and gamma radiation have different impacts on the erythrocyte membrane fluidity, involving, probably, the different rate of energy deposition in the samples and the direct interaction of electrons with the erythrocyte membranes. (authors)

  19. Effects of pulse current on energy consumption and removal of heavy metals during electrodialytic soil remediation

    DEFF Research Database (Denmark)

    Sun, Tian R.; Ottosen, Lisbeth M.

    2012-01-01

    industrially polluted soils were performed. At a current density of 0.1mA/cm2 in soil 1 and 0.2mA/cm2 in soil 2, there was no difference on energy consumption and removal of heavy metals between pulse current and constant current experiments, but at higher current experiments (i.e., 0.2mA/cm2 in soil 1 and 0......The aims of this paper were to investigate the possibility for energy saving when using a pulsed electric field during electrodialytic soil remediation (EDR) and the effect of the pulsed current on removal of heavy metals. Eight experiments with constant and pulse current in the different.......8mA/cm2 in soil 2) the energy was saved 67% and 60% and the removal of heavy metals was increased 17–76% and 31–51% by pulse current in soil 1 and soil 2, respectively. When comparing the voltage drop at different parts of EDR cells, it was found that the voltage drop of the area across cation...

  20. Synchrotron topographic evaluation of strain around craters generated by irradiation with X-ray pulses from free electron laser with different intensities

    Czech Academy of Sciences Publication Activity Database

    Wierzchowski, W.; Wieteska, K.; Sobierajski, R.; Klinger, D.; Pelka, J.; Zymierska, D.; Paulmann, C.; Hau-Riege, S.P.; London, R.A.; Graf, A.; Burian, Tomáš; Chalupský, Jaromír; Gaudin, J.; Krzywinski, J.; Moeller, S.; Messerschmidt, M.; Bozek, J.; Bostedt, C.

    2015-01-01

    Roč. 364, Dec (2015), s. 20-26 ISSN 0168-583X Institutional support: RVO:68378271 Keywords : x-ray free electron laser * soft x-ray lasers * irradiation with femtosecond pulses * silicon Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 1.389, year: 2015

  1. Criteria to average out the chemical shift anisotropy in solid-state NMR when irradiated with BABA I, BABA II, and C7 radiofrequency pulse sequences.

    Science.gov (United States)

    Stephane Mananga, Eugene

    2013-01-01

    Floquet-Magnus expansion is used to study the effect of chemical shift anisotropy in solid-state NMR of rotating solids. The chemical shift interaction is irradiated with two types of radiofrequency pulse sequences: BABA and C7. The criteria for the chemical shift anisotropy to be averaged out in each rotor period are obtained. Copyright © 2013 Elsevier Inc. All rights reserved.

  2. Silica–silica Polyimide Buffered Optical Fibre Irradiation and Strength Experiment at Cryogenic Temperatures for 355 nm Pulsed Lasers

    CERN Document Server

    Takala, E; Bordini, B; Bottura, L; Bremer, J; Rossi, L

    2012-01-01

    A controlled UV-light delivery system is envisioned to be built in order to study the stability properties of superconducting strands. The application requires a wave guide from room temperature to cryogenic temperatures. Hydrogen loaded and unloaded polyimide buffered silica–silica 100 microm core fibres were tested at cryogenic temperatures. A thermal stress test was done at 1.9 K and at 4.2 K which shows that the minimal mechanical bending radius for the fibre can be 10 mm for testing (transmission was not measured). The cryogenic transmission loss was measured for one fibre to assess the magnitude of the transmission decrease due to microbending that takes place during cooldown. UV-irradiation degradation measurements were done for bent fibres at 4.2 K with a deuterium lamp and 355 nm pulsed lasers. The irradiation tests show that the fibres have transmission degradation only for wavelengths smaller than 330 nm due to the two photon absorption. The test demonstrates that the fibres are suitable for the ...

  3. Oxygen diffusion kinetics and reactive lifetimes in bacterial and mammalian cells irradiated with nanosecond pulses of high intensity electrons

    International Nuclear Information System (INIS)

    Epp, E.R.; Weiss, H.; Ling, C.C.; Djordjevic, B.; Kessaris, N.D.

    1975-01-01

    Experiaments have been designed to gain information on the lifetime of oxygen-sensitive species suspected to be produced in critical molecules in irradiated cells and on the time-diffusion of oxygen in cells. An approach developed in this laboratory involves the delivery of two high intensity electron pulses each of 3 ns duration to a thin layer of cells equilibrated with a known concentration of oxygen. The first pulse serves to render the cells totally anoxic by the radiochemical depletion of oxygen; the second is delivered at a time electronically delayed after the first allowing for diffusion of oxygen during this time. Under these conditions the radiosensitivity of E coli B/r has been measured over six decades of interpulse time. Cellular time-diffusion curves constructed from the measurements show that oxygen establishes its sensitizing effect within 10 -4 s after the creation of intracellular anoxia establishing this time as an upper limit to the lifetime of the species. Unusual behaviour of the diffusion curve observed for longer delay times can be explained by a model wherein it is postulated that a radiation-induced inhibiting agent slows down diffusion. Application of this model to the experimental data yields a value of 0.4x10 -5 cm 2 s -1 for the cellular oxygen diffusion coefficient. Similar experiments recently carried out for Serratia marcescens will also be described. The oxygen effect in cultured HeLa cells exposed to single short electron pulses has been examined over a range of oxygen concentrations. A family of breaking survival curves was obtained similar to those previously measured for E coli B/r by this laboratory. The data appear to be reasonably consistent with a physicochemical mechanism involving the radiochemical depletion of oxygen previously invoked for bacteria. (author)

  4. Histological examination of the oral mucosa after fractional diode laser irradiation with different power and pulse duration

    Science.gov (United States)

    Belikov, Andrey V.; Ermolaeva, Ludmila A.; Korzhevsky, Dmitriy E.; Sergeeva, Elena S.; Semyashkina, Yulia V.; Antropova, Maria M.; Fedotov, Denis Y.; Zaitseva, Maria A.; Kashina, Tatiana V.

    2018-04-01

    Optical and histological methods were used to examination of influence the power and pulse duration of 980-nm diode laser to the dimensions and morphology of tissue around fractional micro injuries created by the radiation of that laser in the oral mucosa of rats in vivo. The power of laser radiation (P) varied in the range of 1÷21 W, and its pulse duration (tp) - in the range 50÷500 ms. Histological examination showed that in the mucosa of the oral cavity after the laser fractional irradiation, there following effects are found: a tissue defect, a transudate in the lumen of ablative micro injury, stretching and compacting effect of the nuclei of the basal epithelium, the disappearance of granules of the keratohialin, destroying the structure of the connective tissue, erythrocyte stasis in the vessels, the disappearance of transverse striation in the muscle fibers in muscle layer. It has been found that ablative micro injury begins to form up at P = 5 W, tp = 100 ms and affects only the epithelial layer of the mucosa. At P = 7 W, tp = 120 ms, the ratio of width to depth of ablative micro injury is 1 : 1, and at P = 10 W, tp = 100 ms, an ablative micro column with ratio of 1 : 1.5 is formed in the epithelial and submucosal layers of the mucosa. The laser effect with P = 15 W, tp = 200 ms leads to lengthening of the ablation micro-column to 1 : 2, with the bottom of the ablative micro column reaching the muscular layer. With a further growth of laser power or pulse duration, the width of the micro injury increases, and the growth of the micro injury depth is slowed down so that the micro column buildup is ceased.

  5. 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.

  6. 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.

  7. Self-sustained Oscillation Pulsed Air Blowing System for Energy Saving

    Institute of Scientific and Technical Information of China (English)

    CAI Maolin; XU Weiqing

    2010-01-01

    Currently, many studies have been made for years on dimensions of pneumatic nozzle, which influence the flow characteristic of blowing system. For the purpose of outputting the same blowing force, the supply pressure could be reduced by decreasing the ratio of length to diameter of nozzle. The friction between high speed air and pipe wall would be reduced if the nozzle is designed to be converging shape comparing with straight shape. But the volume flow and pressure, discussed in these studies, do not describe energy loss of the blowing system directly. Pneumatic power is an innovative principle to estimate pneumatic system's energy consumption directly. Based on the above principle, a pulse blowing method is put forward for saving energy. A flow experiment is carried out, in which the high speed air flows from the pulse blowing system and continuous blowing system respectively to a plate with grease on top. Supply pressure and the volume of air used for removing the grease are measured to calculate energy consumption. From the experiment result, the pulse blowing system performs to conserve energy comparing with the continuous blowing system. The frequency and duty ratio of pulse flow influence the blowing characteristic. The pulse blowing system performs to be the most efficient at the specified frequency and duty ratio. Then a pneumatic self-oscillated method based on air operated valve is put forward to generate pulse flow. A simulation is made about dynamic modeling the air operated valve and calculating the motion of the valve core and output pressure. The simulation result verifies the system to be able to generate pulse flow, and predicts the key parameters of the frequency and duty ratio measured by experiment well. Finally, on the basis of simplifying and solution of the pulse blowing system's mathematic model, the relationship between system's frequency duty ratio and the dimensions of components is simply described with four algebraic equations. The

  8. Void shrinkage in stainless steel during high energy electron irradiation

    International Nuclear Information System (INIS)

    Singh, B.N.; Foreman, A.J.E.

    1976-03-01

    During irradiation of thin foils of an austenitic stainless steel in a high voltage electron microscope, steadily growing voids have been observed to suddenly shrink and disappear at the irradiation temperature of 650 0 Cthe phenomenon has been observed in specimens both with and withoutimplanted helium. Possible mechanisms for void shrinkage during irradiation are considered. It is suggested that the dislocation-pipe-diffusion of vacancies from or of self-interstitial atoms to the voids can explain the shrinkage behaviour of voids observed during our experiments. (author)

  9. Temporal reflectance from a light pulse irradiated medium embedded with highly scattering cores

    International Nuclear Information System (INIS)

    Hsu Peifeng; Lu Xiaodong

    2007-01-01

    This paper presents a new approach to utilize ultrashort pulsed laser for optical diagnostics with numerical simulations. The method is based on the use of ultrafast pulses with a pulsewidth selected according to the probed medium's radiative property and/or size. Our previous work in nonhomogeneous media has shown that the resulting time-resolved reflectance signal will have a unique characteristic: it will show a direct correlation of ballistic photon travel time and interface location, which is in between different layers or nonhomogeneous regions. The premise is based on utilizing the medium's structural information carried by the ballistic and snake photons without being masked by the diffuse photons. In this study, the space-time correlation is further explored in the case of minimally scattered photons from a large scattering coefficient core region embedded within a less-scattering medium. Time-resolved reflectance signals of the single scattering core and multiple scattering cores within a three-dimensional medium demonstrate the concept and illustrate the additional effect due to the scattered photons from the core region. A unique temporal signal profile's correlation at various detector positions with respect to the scattering core is explained in detail. The result has important implications. This approach will lead to a much simpler and more precise determination of the probed medium's composition or structure. Due to the large computational requirement to obtain the physical details of the light pulse propagation inside highly scattering multi-dimensional media, the reverse Monte-Carlo method is used. The potential applications of the method include non-destructive diagnostics, optical imaging, and remote sensing of underwater objects

  10. Surface modification of polymethylmethacrylate irradiated with 60 fs single laser pulses

    Czech Academy of Sciences Publication Activity Database

    Klinger, D.; Sobierajski, R.; Nietubyc, R.; Krzywinski, J.; Pelka, J.; Juha, Libor; Jurek, M.; Zymierska, D.; Guizard, S.; Merdji, H.

    2009-01-01

    Roč. 78, Suppl. 10 (2009), S71-S74 ISSN 0969-806X R&D Projects: GA AV ČR KAN300100702; GA MŠk LC510; GA MŠk(CZ) LC528; GA MŠk LA08024; GA AV ČR IAA400100701 Institutional research plan: CEZ:AV0Z10100523 Keywords : polymethylmethacrylate (PMMA) * IR laser ablation * femtosecond laser pulse Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.149, year: 2009

  11. Method and apparatus for obtaining very high energy laser pulses: photon cyclotron

    International Nuclear Information System (INIS)

    Vali, V.; Krogstad, R.S.; Goldstein, R.

    1975-01-01

    Apparatus is arranged in selected embodiments of several combinations, each sometimes being referred to as a system, and each embodiment establishing a large enclosable chamber containing a laser energy reacting medium through which a laser beam is created. When laser energy pulses of such a beam are created, they are guided in a continuous path using reflectors in this chamber, and they receive supplemental energy units from multiple spaced laser pumps. Each laser pump is effective in respect to its own inverted population laser energy source, and each laser pump is triggered by an overall excitation control system. The laser beam is thereby supplemented to a higher level at each laser pump. Yet at all times the laser energy reacting medium remains at a level below super radiance. A working unit or working pulse of a laser beam is allowed to escape from each large enclosable chamber through an escape exit only when a preselected very high energy level is reached. The escape exit of this chamber may be designed to be destroyed by the exiting high level pulse energy of the laser beam. Also an escape exit may be opened upon the operation of a piezoelectric decoupler. (U.S.)

  12. Surface modification of TC4 titanium alloy by high current pulsed electron beam (HCPEB) with different pulsed energy densities

    International Nuclear Information System (INIS)

    Gao, Yu-kui

    2013-01-01

    Highlights: •The hardness changes were determined by nanoindention method. •The surface integrity changes were investigated by different techniques. •The mechanism was analyzed based on AFM and TEM investigations. -- Abstract: Surface changes including surface topography and nanohardness distribution along surface layer were investigated for TC4 titanium alloy by different energy densities of high current pulsed electron beam (HCPEB). The surface topography was characterized by SEM and AFM, and cross-sectional TEM observation was performed to reveal the surface modification mechanism of TC4 titanium alloy by HCPEB. The surface roughness was modified by HCPEB and the polishing mechanism was analyzed by studying the cross section microstructure of electron beam treated specimens by SEM. The fine grain structure inherited from the rapid solidification of the melted layer as well as the strain hardening of the sub-surface are two of the factors responsible the increase in nanohardness

  13. High-voltage many-pulses generator with inductive energy store and fuse

    International Nuclear Information System (INIS)

    Kovalev, V.P.; Diyankov, V.S.; Kormilitsin, A.I.; Lavrent'ev, B.N.

    1996-01-01

    The high-voltage generator with inductive energy store and fuses as opening switch that generate series of powerful pulses is considered. This generator differs from the ordinary generator with inductive store by the cross-section of the series copper wires. The parameters of the wires are chosen based on empirical relations. The generation principle was tested on the two high-voltage generators with characteristic impedance 2.2 ohm, 4 ohm and with output voltages of 140 kV and 420 kV, respectively. Copper wires 0.1 to 0.23 mm in diameter were used. Series of 2 to 5 pulses of 100 to 300 ns duration, 400 to 1000 kV amplitude and 1 - 10 GW power were obtained. Pulses can be both the same and different. Two successive bremsstrahlung radiation pulses were obtain on the EMIR-M and IGUR-3 devices. Series power megavolt pulses can be generated with a power exceeding 10 11 W, pulse duration of 10 -3 to 10 -6 s, and time interval between them 10 -7 to 10 -5 s. (author). 4 figs., 2 refs

  14. High-voltage many-pulses generator with inductive energy store and fuse

    Energy Technology Data Exchange (ETDEWEB)

    Kovalev, V P; Diyankov, V S; Kormilitsin, A I; Lavrent` ev, B N [All-Russian Research Inst. of Technical Physics, Snezhinsk (Russian Federation)

    1997-12-31

    The high-voltage generator with inductive energy store and fuses as opening switch that generate series of powerful pulses is considered. This generator differs from the ordinary generator with inductive store by the cross-section of the series copper wires. The parameters of the wires are chosen based on empirical relations. The generation principle was tested on the two high-voltage generators with characteristic impedance 2.2 ohm, 4 ohm and with output voltages of 140 kV and 420 kV, respectively. Copper wires 0.1 to 0.23 mm in diameter were used. Series of 2 to 5 pulses of 100 to 300 ns duration, 400 to 1000 kV amplitude and 1 - 10 GW power were obtained. Pulses can be both the same and different. Two successive bremsstrahlung radiation pulses were obtain on the EMIR-M and IGUR-3 devices. Series power megavolt pulses can be generated with a power exceeding 10{sup 11} W, pulse duration of 10{sup -3} to 10{sup -6} s, and time interval between them 10{sup -7} to 10{sup -5} s. (author). 4 figs., 2 refs.

  15. A novel method of calculating the energy deposition curve of nanosecond pulsed surface dielectric barrier discharge

    International Nuclear Information System (INIS)

    He, Kun; Wang, Xinying; Lu, Jiayu; Cui, Quansheng; Pang, Lei; Di, Dongxu; Zhang, Qiaogen

    2015-01-01

    To obtain the energy deposition curve is very important in the fields to which nanosecond pulse dielectric barrier discharges (NPDBDs) are applied. It helps the understanding of the discharge physics and fast gas heating. In this paper, an equivalent circuit model, composed of three capacitances, is introduced and a method of calculating the energy deposition curve is proposed for a nanosecond pulse surface dielectric barrier discharge (NPSDBD) plasma actuator. The capacitance C d and the energy deposition curve E R are determined by mathematically proving that the mapping from C d to E R is bijective and numerically searching one C d that satisfies the requirement for E R to be a monotonically non-decreasing function. It is found that the value of capacitance C d varies with the amplitude of applied pulse voltage due to the change of discharge area and is dependent on the polarity of applied voltage. The bijectiveness of the mapping from C d to E R in nanosecond pulse volumetric dielectric barrier discharge (NPVDBD) is demonstrated and the feasibility of the application of the new method to NPVDBD is validated. This preliminarily shows a high possibility of developing a unified approach to calculate the energy deposition curve in NPDBD. (paper)

  16. Millijoule Pulse Energy Second Harmonic Generation With Single-Stage Photonic Bandgap Rod Fiber Laser

    DEFF Research Database (Denmark)

    Laurila, Marko; Saby, Julien; Alkeskjold, Thomas Tanggaard

    2011-01-01

    In this paper, we demonstrate, for the first time, a single-stage Q-switched single-mode (SM) ytterbium-doped rod fiber laser delivering record breaking pulse energies at visible and UV light. We use a photonic bandgap rod fiber with a mode field diameter of 59μm based on a new distributed...

  17. Dynamics of bubble generated by low energy pulsed electric discharge in water

    International Nuclear Information System (INIS)

    Pinchuk, M E; Kolikov, V A; Rutberg, Ph G; Leks, A G; Dolinovskaya, R V; Snetov, V N; Stogov, A Yu

    2012-01-01

    Results of investigations of bubble formation and dynamics for discharge in water are presented. Experiments were carried out in discharge chamber with axisymmetric electrode system “wire to wire”. Interelectrode gap was varied from 1 to 10 mm. Energy in a pulse was <1 J. Velocity of bubble expantion and collapse is about several hundreds meter per second at early stage of discharge. Bubble pulsation period is 0.5 – 1 ms. Increasing of energy released in the discharge gap will increase bubble pulsation period. Little bubble was formed by reducing energy input into discharge. But the main stage of discharge always followed by bubble formation. Specific erosion is measured for different energy in pulse and matched up with bubble collapse.

  18. X-ray topographic investigation of the deformation field around spots irradiated by FLASH single pulses

    Czech Academy of Sciences Publication Activity Database

    Wierzchowski, W.; Wieteska, K.; Balcer, T.; Klinger, D.; Sobierajski, R.; Zymierska, D.; Chalupský, Jaromír; Hájková, Věra; Burian, Tomáš; Gleeson, A.J.; Juha, Libor; Tiedtke, K.; Toleikis, S.; Vyšín, Luděk; Wabnitz, H.; Gaudin, J.

    2011-01-01

    Roč. 80, č. 10 (2011), s. 1036-1040 ISSN 0969-806X R&D Projects: GA AV ČR KAN300100702; GA MŠk LC510; GA ČR(CZ) GAP108/11/1312; GA MŠk(CZ) LC528; GA MŠk LA08024; GA AV ČR IAAX00100903; GA MŠk(CZ) ME10046 Institutional research plan: CEZ:AV0Z10100523 Keywords : silicon * FLASH irradiation * x-ray topography * deformation fields Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.227, year: 2011

  19. Pulse shaping and energy storage capabilities of angularly multiplexed KrF laser fusion drivers

    Science.gov (United States)

    Lehmberg, R. H.; Giuliani, J. L.; Schmitt, A. J.

    2009-07-01

    This paper describes a rep-rated multibeam KrF laser driver design for the 500kJ Inertial Fusion test Facility (FTF) recently proposed by NRL, then models its optical pulse shaping capabilities using the ORESTES laser kinetics code. It describes a stable and reliable iteration technique for calculating the required precompensated input pulse shape that will achieve the desired output shape, even when the amplifiers are heavily saturated. It also describes how this precompensation technique could be experimentally implemented in real time on a reprated laser system. The simulations show that this multibeam system can achieve a high fidelity pulse shaping capability, even for a high gain shock ignition pulse whose final spike requires output intensities much higher than the ˜4MW/cm2 saturation levels associated with quasi-cw operation; i.e., they show that KrF can act as a storage medium even for pulsewidths of ˜1ns. For the chosen pulse, which gives a predicted fusion energy gain of ˜120, the simulations predict the FTF can deliver a total on-target energy of 428kJ, a peak spike power of 385TW, and amplified spontaneous emission prepulse contrast ratios IASE/Ilaser.

  20. Dependence of Initial Oxygen Concentration on Ozone Yield Using Inductive Energy Storage System Pulsed Power Generator

    Science.gov (United States)

    Go, Tomio; Tanaka, Yasushi; Yamazaki, Nobuyuki; Mukaigawa, Seiji; Takaki, Koichi; Fujiwara, Tamiya

    Dependence of initial oxygen concentration on ozone yield using streamer discharge reactor driven by an inductive energy storage system pulsed power generator is described in this paper. Fast recovery type diodes were employed as semiconductor opening switch to interrupt a circuit current within 100 ns. This rapid current change produced high-voltage short pulse between a secondary energy storage inductor. The repetitive high-voltage short pulse was applied to a 1 mm diameter center wire electrode placed in a cylindrical pulse corona reactor. The streamer discharge successfully occurred between the center wire electrode and an outer cylinder ground electrode of 2 cm inner diameter. The ozone was produced with the streamer discharge and increased with increasing pulse repetition rate. The ozone yield changed in proportion to initial oxygen concentration contained in the injected gas mixture at 800 ns forward pumping time of the current. However, the decrease of the ozone yield by decreasing oxygen concentration in the gas mixture at 180 ns forward pumping time of the current was lower than the decrease at 800 ns forward pumping time of the current. This dependence of the initial oxygen concentration on ozone yield at 180 ns forward pumping time is similar to that of dielectric barrier discharge reactor.

  1. Experimental and modelling study of pulsed optically stimulated luminescence in quartz, marble and beta irradiated salt

    International Nuclear Information System (INIS)

    Pagonis, V; Mian, S M; Barnold, C; Chithambo, M L; Christensen, E

    2009-01-01

    Optical stimulation luminescence (OSL) signals can be obtained using continuous-wave optical stimulation (CW-OSL), the linear modulation optical stimulation method (LM-OSL) and the time-resolved optical stimulation (TR-OSL) method. During TR-OSL measurements, the stimulation and emission of luminescence are experimentally separated in time by using short light pulses. This paper presents new TR-OSL data for annealed high purity synthetic quartz, for marble and for commercially available iodized salt. A new type of behaviour for TR-OSL signals for quartz and iodized salt is presented, in which the OSL signal exhibits a nonmonotonic behaviour during optical stimulation; this type of behaviour has not been reported previously in the literature for quartz. Furthermore, a luminescence component with very long luminescence lifetime is reported for some quartz aliquots, which may be due to the presence of a delayed-OSL (DOSL) mechanism in quartz. A new kinetic model for TR-OSL in quartz is presented, which is based on a main electron trap and on several luminescence centres. The model is used to quantitatively fit several sets of experimental data of pulsed optically stimulated luminescence from quartz.

  2. Relaxation of ion energy spectrum just after turbulent heating pulse in TRIAM-1 tokamak

    International Nuclear Information System (INIS)

    Nakamura, Kazuo; Hiraki, Naoji; Nakamura, Yukio; Itoh, Satoshi

    1982-01-01

    The temporal evolution and spatial profile of the ion energy spectrum just after the application of a toroidal current pulse for turbulent heating are investigated experimentally in the TRIAM-1 tokamak and also numerically using the Fokker-Planck equation. The two-component ion energy spectrum formed by turbulent heating relaxes to a single one within tausub(i) (the ion collision time). (author)

  3. Electron Beam Energy Compensation by Controlling RF Pulse Shape

    CERN Document Server

    Kii, T; Kusukame, K; Masuda, K; Nakai, Y; Ohgaki, H; Yamazaki, T; Yoshikawa, K; Zen, H

    2005-01-01

    We have studied on improvement of electron beam macropulse properties from a thermionic RF gun. Though a thermionic RF gun has many salient features, there is a serious problem that back-bombardment effect worsens quality of the beam. To reduce beam energy degradation by this effect, we tried to feed non-flat RF power into the gun. As a result, we successfully obtained about 1.5 times longer macropulse and two times larger total charge per macropulse. On the other hand, we calculated transient evolution of RF power considering non-constant beam loading. The beam loading is evaluated from time evolution of cathode temperature, by use of one dimensional heat conduction model and electron trajectories' calculations by a particle simulation code. Then we found good agreement between the experimental and calculation results. Furthermore, with the same way, we studied the electron beam output dependence on the cathode radius.

  4. Feasibility for the disinfestation of pulses and cereal grains by irradiation

    International Nuclear Information System (INIS)

    Mansour, M.; Al-Bachir, M.

    1994-01-01

    The faba bean seed beetle, Bruchus dentipes Baudi, the lentil seed beetle, B. Ervi Froel, and the European lentil seed beetle, B. Lentis Froel are the most important insect pests of lentil and faba bean in Syria. Adults lay their eggs on the green pods in the field and immature stages develop inside the seeds. Infestation rate differs from year to year and from one location to another. In 1991, it ranged between 9.6 and 13.90 for lentil seeds and 31.00 to 57.39% for faba bean seeds depending on the region. This reduced the economic value by about 50% for faba bean seeds and 20-30% for lentil seeds. Current disinfestation methods are unsafe and not adequately effective. Ionizing radiation could be an alternative approach. An investigation was initiated to determine the possibility of applying the irradiation disinfestation technique against these pests. The dose of gamma radiation needed for disinfesting faba bean seeds infested with B. dentipes was found to be 90 Gy for the last two larval instars. Immature stages of B. ervi and B. lentils develop very rapidly in the field and reach the pupal or adult stage by harvest. This makes the application of this technique for disinfesting lentil seeds of little or no value. However, the results indicate that the irradiation disinfestation method could be an advantageous approach for disinfesting faba bean seeds. (author). 38 refs, 1 fig., 4 tabs

  5. Feasibility for the disinfestation of pulses and cereal grains by irradiation

    International Nuclear Information System (INIS)

    Mansour, M.Y.; Al-Bachir, M.

    1993-05-01

    The faba bean seed beetle,Bruchus Dentipes Baudi, the lentil seed beetle, B.ervi Froel, and the European lentil seed beetle, B.lentis Froel are the most important insect pests of lentil and faba bean in Syria. Adults lay their eggs on the green pods in the field and immature stages develop inside the seeds. Infestation rate differs from year to year and from one location to another. In 1991, it ranged between 9.6 and 13.90 for lentil seeds and 31.00 to 57.39% for faba bean seeds depending on the region. This reduced the economic value by about 50% for faba bean seeds and 20 - 30% for lentil seeds. Current disinfestation methods are unsafe and not adequately effective. Ionizing radiation could be an alternative approach. An investigation was initiated to determine the possibility of applying the irradiation disinfestation technique against these pests. The dose of gamma radiation needed for disinfecting faba bean seeds infested with B.Dentipes was found to be 90 Gy for the last two larval instars. Immature stages of B.ervi and B.lentis develop very rapidly in the field and reach the pupal or adult stage by harvest. This makes the application of this technique for disinfecting lentil seeds of little or no value. However, the results indicate that the irradiation disinfestation method could be an advantageous approach for disinfecting faba bean seeds. (author). 38 refs., 4 tabs., 1 fig

  6. Electromagnetic cascade in high-energy electron, positron, and photon interactions with intense laser pulses

    Science.gov (United States)

    Bulanov, S. S.; Schroeder, C. B.; Esarey, E.; Leemans, W. P.

    2013-06-01

    The interaction of high-energy electrons, positrons, and photons with intense laser pulses is studied in head-on collision geometry. It is shown that electrons and/or positrons undergo a cascade-type process involving multiple emissions of photons. These photons can consequently convert into electron-positron pairs. As a result charged particles quickly lose their energy developing an exponentially decaying energy distribution, which suppresses the emission of high-energy photons, thus reducing the number of electron-positron pairs being generated. Therefore, this type of interaction suppresses the development of the electromagnetic avalanche-type discharge, i.e., the exponential growth of the number of electrons, positrons, and photons does not occur in the course of interaction. The suppression will occur when three-dimensional effects can be neglected in the transverse particle orbits, i.e., for sufficiently broad laser pulses with intensities that are not too extreme. The final distributions of electrons, positrons, and photons are calculated for the case of a high-energy e-beam interacting with a counterstreaming, short intense laser pulse. The energy loss of the e-beam, which requires a self-consistent quantum description, plays an important role in this process, as well as provides a clear experimental observable for the transition from the classical to quantum regime of interaction.

  7. Transformation between divacancy defects induced by an energy pulse in graphene.

    Science.gov (United States)

    Xia, Jun; Liu, XiaoYi; Zhou, Wei; Wang, FengChao; Wu, HengAn

    2016-07-08

    The mutual transformations among the four typical divacancy defects induced by a high-energy pulse were studied via molecular dynamics simulation. Our study revealed all six possible mutual transformations and found that defects transformed by absorbing energy to overcome the energy barrier with bonding, debonding, and bond rotations. The reversibility of defect transformations was also investigated by potential energy analysis. The energy difference was found to greatly influence the transformation reversibility. The direct transformation path was irreversible if the energy difference was too large. We also studied the correlation between the transformation probability and the input energy. It was found that the transformation probability had a local maxima at an optimal input energy. The introduction of defects and their structural evolutions are important for tailoring the exceptional properties and thereby performances of graphene-based devices, such as nanoporous membranes for the filtration and desalination of water.

  8. Secondary radiation dose during high-energy total body irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Janiszewska, M.; Raczkowski, M. [Lower Silesian Oncology Center, Medical Physics Department, Wroclaw (Poland); Polaczek-Grelik, K. [University of Silesia, Medical Physics Department, Katowice (Poland); Szafron, B.; Konefal, A.; Zipper, W. [University of Silesia, Department of Nuclear Physics and Its Applications, Katowice (Poland)

    2014-05-15

    The goal of this work was to assess the additional dose from secondary neutrons and γ-rays generated during total body irradiation (TBI) using a medical linac X-ray beam. Nuclear reactions that occur in the accelerator construction during emission of high-energy beams in teleradiotherapy are the source of secondary radiation. Induced activity is dependent on the half-lives of the generated radionuclides, whereas neutron flux accompanies the treatment process only. The TBI procedure using a 18 MV beam (Clinac 2100) was considered. Lateral and anterior-posterior/posterior-anterior fractions were investigated during delivery of 2 Gy of therapeutic dose. Neutron and photon flux densities were measured using neutron activation analysis (NAA) and semiconductor spectrometry. The secondary dose was estimated applying the fluence-to-dose conversion coefficients. The main contribution to the secondary dose is associated with fast neutrons. The main sources of γ-radiation are the following: {sup 56}Mn in the stainless steel and {sup 187}W of the collimation system as well as positron emitters, activated via (n,γ) and (γ,n) processes, respectively. In addition to 12 Gy of therapeutic dose, the patient could receive 57.43 mSv in the studied conditions, including 4.63 μSv from activated radionuclides. Neutron dose is mainly influenced by the time of beam emission. However, it is moderated by long source-surface distances (SSD) and application of plexiglass plates covering the patient body during treatment. Secondary radiation gives the whole body a dose, which should be taken into consideration especially when one fraction of irradiation does not cover the whole body at once. (orig.) [German] Die zusaetzliche Dosis durch sekundaere Neutronen- und γ-Strahlung waehrend der Ganzkoerperbestrahlung mit Roentgenstrahlung aus medizinischen Linearbeschleunigern wurde abgeschaetzt. Bei der Emission hochenergetischer Strahlen zur Teletherapie finden hauptsaechlich im Beschleuniger

  9. Particle-in-cell simulations of high energy electron production by intense laser pulses in underdense plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Susumu, Kato; Eisuke, Miura; Kazuyoshi, Koyama [National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki (Japan); Mitsumori, Tanimoto [Meisei Univ., Dept. of Electrical Engineering, Hino, Tokyo (Japan); Masahiro, Adachi [Hiroshima Univ., Graduate school of Advanced Science of Matter, Higashi-Hiroshima, Hiroshima (Japan)

    2004-07-01

    The propagation of intense laser pulses and the generation of high energy electrons from underdense plasmas are investigated using two dimensional particle-in-cell simulations. When the ratio of the laser power to the critical power of relativistic self-focusing gets the optimal value, the laser pulse propagates in a steady way and electrons have maximum energies. (author)

  10. Particle-in-cell simulations of high energy electron production by intense laser pulses in underdense plasmas

    International Nuclear Information System (INIS)

    Susumu, Kato; Eisuke, Miura; Kazuyoshi, Koyama; Mitsumori, Tanimoto; Masahiro, Adachi

    2004-01-01

    The propagation of intense laser pulses and the generation of high energy electrons from underdense plasmas are investigated using two dimensional particle-in-cell simulations. When the ratio of the laser power to the critical power of relativistic self-focusing gets the optimal value, the laser pulse propagates in a steady way and electrons have maximum energies. (author)

  11. Influence of e-Beam Irradiation on the Performance of Energy Storage and Conversion Electrode

    Energy Technology Data Exchange (ETDEWEB)

    Baeok, Sung Hyeon; Jo, Won Jun; Lee, Duwon; Lee, Myung An [Inha Univ., Incheon (Korea, Republic of); Shin, Joong Hyeok; Lee, Byung Cheol [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-07-01

    Electron beam irradiation was known as an effective method to improve the stability and performance of electrodes by varying the chemical and physical properties. It has been reported that surface morphology, oxidation state, optical properties, and electrochemical properties can be modified by e-beam irradiation. In this work, influence of electron beam irradiation on the performance of electrode was studied for the applications in energy storage and conversion, such as secondary battery, supercapacitor, and fuel cell. Changes in physical and chemical properties of electrodes before and after e-beam irradiation were investigated. The crystallinity of the synthesized materials was investigated by X-ray diffraction, and the oxidation states were determined by X-ray photoelectron spectroscopy. Scanning electron microscopy was utilized to examine surface morphology. Crystallinity, surface morphology, and oxidation state were significantly changed by electron beam irradiation, and were found to be strongly dependent on irradiation time.

  12. Measurement of ablation threshold of oxide-film-coated aluminium nanoparticles irradiated by femtosecond laser pulses

    International Nuclear Information System (INIS)

    Chefonov, O V; Ovchinnikov, A V; Il'ina, I V; Agranat, M B

    2016-01-01

    We report the results of experiments on estimation of femtosecond laser threshold intensity at which nanoparticles are removed from the substrate surface. The studies are performed with nanoparticles obtained by femtosecond laser ablation of pure aluminium in distilled water. The attenuation (or extinction, i.e. absorption and scattering) spectra of nanoparticles are measured at room temperature in the UV and optical wavelength ranges. The size of nanoparticles is determined using atomic force microscopy. A new method of scanning photoluminescence is proposed to evaluate the threshold of nanoparticle removal from the surface of a glass substrate exposed to IR femtosecond laser pulses with intensities 10 11 – 10 13 W cm -2 . (interaction of laser radiation with matter)

  13. Improved irradiation tolerance of reactive gas pulse sputtered TiN coatings with a hybrid architecture of multilayered and compositionally graded structures

    Science.gov (United States)

    Liang, Wei; Yang, Jijun; Zhang, Feifei; Lu, Chenyang; Wang, Lumin; Liao, Jiali; Yang, Yuanyou; Liu, Ning

    2018-04-01

    This study investigates the improved irradiation tolerance of reactive gas pulse (RGP) sputtered TiN coatings which has hybrid architecture of multilayered and compositionally graded structures. The multilayered RGP-TiN coating is composed of hexagonal close-packed Ti phase and face-centred cubic TiN phase sublayers, where the former sublayer has a compositionally graded structure and the latter one maintains constant stoichiometric atomic ratio of Ti:N. After 100 keV He ion irradiation, the RGP-TiN coating exhibits improved irradiation resistance compared with its single layered (SL) counterpart. The size and density of He bubbles are smaller in the RGP-TiN coating than in the SL-TiN coating. The irradiation-induced surface blistering of the coatings shows a similar tendency. Meanwhile, the irradiation hardening and adhesion strength of the RGP-TiN coatings were not greatly affected by He irradiation. Moreover, the irradiation damage tolerance of the coatings can be well tuned by changing the undulation period number of N2 gas flow rate. Detailed analysis suggested that this improved irradiation tolerance could be related to the combined contribution of the multilayered and compositionally graded structures.

  14. The Effect of Local Irradiation in Prevention and Reversal of Acute Rejection of Transplanted Kidney with High-dose Steroid Pulse

    International Nuclear Information System (INIS)

    Kim, I. H.; Ha, S. W.; Park, C. I.; Kim, S. T.

    1986-01-01

    From 1979 to 1984, 39 local allograft irradiations were given to 29 patients: 10 irradiations were administered for prevention and 29 for reversal of acute rejection of transplanted kidney. Three doses of 150 cGy every other day were combined with high-dose of methylprednisolone pulse (1 gm/day) for 3 days. For prevention of acute rejection, local irradiation was delivered on the days 1, 3, and 5 after the transplantation, and for reversal, irradiation started after the diagnosis of acute rejection. Eight out of 10 patients irradiated for prevention had acute allograft rejection, and, what is more, there was no surviving graft at 15 months after transplantation. Reversal of acute rejection was achieved in 71%. When the pre-irradiation level of serum creatinine was below 5.5 mg%, the reversal rate was 93%, but above 5.5 mg% the reversal rate was only 17% (p<0.01). Reirradiation after failure was not successful. Among 15 reversed patients, 7 (47%) had subsequent rejection (s). The functional graft survivals at 6 month, 1, 2, and 3 year were 70%, 65%, 54%, and 65%, respectively. Therapeutic irradiation resulted in better graft survival when serum creatinine was below 5.5 mg% (p<0.001) or when irradiation started within 15 days after the diagnosis of acute rejection (p<0.001)

  15. Scanning of irradiated silicon detectors using $\\alpha$ particles and low energy protons

    CERN Document Server

    Casse, G L; Glaser, M; Kohout, Z; Konícek, J; Lemeilleur, F; Leroy, C; Linhart, V; Mares, J J; Pospísil, S; Roy, P; Sopko, B; Sinor, M; Svejda, J; Vorobel, V; Wilhelm, I

    1999-01-01

    In a spectroscopic study of non-irradiated and proton-irradiated silicon diodes, the detectors were illuminated from the front side and from the rear side by various alpha particle sources (mainly ThC') and by monoenergetic protons with energies from 1.0 to 2.5~MeV. Their response characteristics have been studied as a function of the incoming particle energy and the applied bias voltage. The charge collection efficiency was determined as a function of fluence

  16. Present status of ESNIT (energy selective neutron irradiation test facility) program

    International Nuclear Information System (INIS)

    Noda, K.; Ohno, H.; Sugimoto, M.; Kato, Y.; Matsuo, H.; Watanabe, K.; Kikuchi, T.; Sawai, T.; Usui, T.; Oyama, Y.; Kondo, T.

    1994-01-01

    The present status of technical studies of a high energy neutron irradiation facility, ESNIT (energy selective neutron irradiation test facility), is summarized. Technological survey and feasibility studies of ESNIT have continued since 1988. The results of technical studies of the accelerator, the target and the experimental systems in ESNIT program were reviewed by an International Advisory Committee in February 1993. Recommendations for future R and D on ESNIT program are also summarized in this paper. ((orig.))

  17. Immediate remediation of heavy metal (Cr(VI)) contaminated soil by high energy electron beam irradiation

    International Nuclear Information System (INIS)

    Zhang, Jing; Zhang, Guilong; Cai, Dongqing; Wu, Zhengyan

    2015-01-01

    Highlights: • An immediate remediation method for Cr(VI) contaminated soil (CCS) was developed. • High energy electron beam (HEEB) irradiation could reduce Cr(VI) in CCS to Cr(III). • This effect was attributed to electrons, hydrated electrons, and reductive radicals. • This remediation method was effective, environmentally friendly, and low-cost. - Abstract: This work developed an immediate and high-performance remediation method for Cr(VI) contaminated soil (CCS) using high energy electron beam (HEEB) irradiation. The result indicated that, compared with γ-ray irradiation, HEEB irradiation displayed a significant reduction efficiency on Cr(VI) in CCS to Cr(III) with substantially lower toxicity, which was mainly attributed to the reduction effects of electrons, hydrated electrons, and reductive radicals generated in the irradiation process of HEEB. This work could provide a one-step and effective method for the remediation of heavy metal contaminated soil (HMCS)

  18. Immediate remediation of heavy metal (Cr(VI)) contaminated soil by high energy electron beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jing; Zhang, Guilong [Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences and Anhui Province, Hefei 230031 (China); Bioenergy Forest Research Center of State Forestry Administration, Hefei 230031 (China); Cai, Dongqing, E-mail: dqcai@ipp.ac.cn [Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences and Anhui Province, Hefei 230031 (China); Bioenergy Forest Research Center of State Forestry Administration, Hefei 230031 (China); Wu, Zhengyan, E-mail: zywu@ipp.ac.cn [Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences and Anhui Province, Hefei 230031 (China); Bioenergy Forest Research Center of State Forestry Administration, Hefei 230031 (China)

    2015-03-21

    Highlights: • An immediate remediation method for Cr(VI) contaminated soil (CCS) was developed. • High energy electron beam (HEEB) irradiation could reduce Cr(VI) in CCS to Cr(III). • This effect was attributed to electrons, hydrated electrons, and reductive radicals. • This remediation method was effective, environmentally friendly, and low-cost. - Abstract: This work developed an immediate and high-performance remediation method for Cr(VI) contaminated soil (CCS) using high energy electron beam (HEEB) irradiation. The result indicated that, compared with γ-ray irradiation, HEEB irradiation displayed a significant reduction efficiency on Cr(VI) in CCS to Cr(III) with substantially lower toxicity, which was mainly attributed to the reduction effects of electrons, hydrated electrons, and reductive radicals generated in the irradiation process of HEEB. This work could provide a one-step and effective method for the remediation of heavy metal contaminated soil (HMCS)

  19. Experimental determination of the thermal contact conductance between two solid surfaces by the energy pulse technique

    International Nuclear Information System (INIS)

    Rubin, Gerson Antonio

    1979-01-01

    An experimental procedure for the determination of the thermal contact conductance between two solid surfaces as a function of the contact pressure and the energy of the laser radiation has been developed using the laser pulse method. A rubi laser with variable energy levels was employed as a radiating pulse energy source. The laser beam was allowed to impinge perpendicularly on the front face of a electrolytic iron 73 4 . The temperature fluctuations resulting on the back surface of the sample was detected by a thermocouple, which Is coupled to a PDP-11/45 Computer 32 Kbytes of memory, through a Analog-Digital Converter. A theoretical function, derived exclusively for the problem mentioned in this work, was adjusted by a method of least square fitting of experimental results. This adjustment yielded the value of a parameter related to the contact conductance between two surfaces. The experimental error obtained for the thermal contact conductance was +- 4.9%. (author)

  20. Numerical study on increasing mass flow ratio by energy deposition of high frequency pulsed laser

    International Nuclear Information System (INIS)

    Wang Diankai; Hong Yanji; Li Qian

    2013-01-01

    The mass flow ratio (MFR) of air breathing ramjet inlet would be decreased, when the Mach number is lower than the designed value. High frequency pulsed laser energy was deposited upstream of the cowl lip to reflect the stream so as to increase the MFR. When the Mach number of the flow was 5.0, and the static pressure and temperature of the flow were 2 551.6 Pa and 116.7 K, respectively, two-dimensional non-stationary compressible RANS equations were solved with upwind format to study the mechanisms of increasing MFR by high frequency pulsed laser energy deposition. The laser deposition frequency was 100 kHz and the average power was 500 W. The crossing point of the first forebody oblique shock and extension line of cowl lip was selected as the expected point. Then the deposition position was optimized by searching near the expected point. The results indicate that with the optimization of laser energy deposition position, the MFR would be increased from 63% to 97%. The potential value of increasing MFR by high frequency pulsed laser energy deposition was proved. The method for selection of the energy deposition position was also presented. (authors)

  1. Kinetic-energy induced smoothening and delay of epitaxial breakdown in pulsed-laser deposition

    International Nuclear Information System (INIS)

    Shin, Byungha; Aziz, Michael J.

    2007-01-01

    We have isolated the effect of kinetic energy of depositing species from the effect of flux pulsing during pulsed-laser deposition (PLD) on surface morphology evolution of Ge(001) homoepitaxy at low temperature (100 deg. C). Using a dual molecular beam epitaxy (MBE) PLD chamber, we compare morphology evolution from three different growth methods under identical experimental conditions except for the differing nature of the depositing flux: (a) PLD with average kinetic energy 300 eV (PLD-KE); (b) PLD with suppressed kinetic energy comparable to thermal evaporation energy (PLD-TH); and (c) MBE. The thicknesses at which epitaxial breakdown occurs are ranked in the order PLD-KE>MBE>PLD-TH; additionally, the surface is smoother in PLD-KE than in MBE. The surface roughness of the films grown by PLD-TH cannot be compared due to the early epitaxial breakdown. These results demonstrate convincingly that kinetic energy is more important than flux pulsing in the enhancement of epitaxial growth, i.e., the reduction in roughness and the delay of epitaxial breakdown

  2. High pulse energy sub-nanosecond Tm-doped fiber laser

    Science.gov (United States)

    Cserteg, Andras; Guillemet, Sebastien; Hernandez, Yves; Giannone, Domenico

    2012-02-01

    We report a core pumped thulium-doped fiber amplifier that generates 1.4 μJ pulses at 1980 nm with a repetition rate of 3.6 MHz preserving the original spectral bandwidth of the oscillator. The amplifier chain is seeded by a passively modelocked fiber laser with 5 mW output power and the pulses are stretched to 800 picoseconds. The amplifier is core pumped by a single mode erbium fiber laser. The slope efficiency is 35%. To the best of our knowledge, this is the first demonstration of sub nanosecond pulses with energies higher than 1 μJ coming out of a thulium-doped fiber amplifier.

  3. Radiosensitivity of chlorella after medium energy accelerated electron irradiation

    International Nuclear Information System (INIS)

    Roux, J.C.

    1966-06-01

    The survival curves (capability of multiplication) of chlorella pyrenoidosa after irradiations can be used for soft electrons (0.65 and 1 MeV), hence penetrating into only 2 to 4 millimeters of water: the algae are laying on porous membranes and the doses are calculated from the power of the electron beam measured by the electric current on a metallic target or by Fricke's dosimetry. With these techniques, it is showed and discussed the part of anoxia in the radioprotection (magnitude or reduction of the dose calculated from the slope of survival curves: 2.5 ) that is more important than the restoration studied by the fractionation of the dose. The 0.65 and 1 MeV electrons have a biologic effect lesser than 180 keV X-rays (RBE - relative biological efficiency - calculated on the slope of survival curves is 0.92 in aerated irradiation, 0.56 in the deoxygenated irradiation). (author) [fr

  4. In vivo mutagenicity studies in rats mice and Chinese hamsters fed irradiated foodstuffs - chicken, fish, dates, pulses, mangoes and cocoa beans

    International Nuclear Information System (INIS)

    Renner, H.W.

    1982-01-01

    Three in vivo genetic toxicity tests were performed in rats, mice and Chinese hamsters to detect possible mutagenic effects of irradiated chicken, dried dates, fish, cocoa beans, pulses and mangoes. The tests employed were the micronucleus test and sister-chromatid exchange (SCE) test for irradiated and unirradiated samples of all foodstuffs listed, and the spermatogonia test, (including SCE technique) in mice for irradiated and unirradiated chicken, fish and dates only. In the case of cocoa beans, the mutagenicity tests were performed on an additional test group fed beans fumigated with ethylene oxide. The different mammalian species used for the various experiments are given below. None of the tests provided any evidence of mutagenicity induced by irradiation in any of the foodstuffs studied. Moreover, these tests are currently considered to be the most sensitive in vivo mutagenicity tests in mammals. (orig.)

  5. Deposition of thin films and surface modification by pulsed high energy density plasma

    International Nuclear Information System (INIS)

    Yan Pengxun; Yang Size

    2002-01-01

    The use of pulsed high energy density plasma is a new low temperature plasma technology for material surface treatment and thin film deposition. The authors present detailed theoretical and experimental studies of the production mechanism and physical properties of the pulsed plasma. The basic physics of the pulsed plasma-material interaction has been investigated. Diagnostic measurements show that the pulsed plasma has a high electron temperature of 10-100 eV, density of 10 14 -10 16 cm -3 , translation velocity of ∼10 -7 cm/s and power density of ∼10 4 W/cm 2 . Its use in material surface treatment combines the effects of laser surface treatment, electron beam treatment, shock wave bombardment, ion implantation, sputtering deposition and chemical vapor deposition. The metastable phase and other kinds of compounds can be produced on low temperature substrates. For thin film deposition, a high deposition ratio and strong film to substrate adhesion can be achieved. The thin film deposition and material surface modification by the pulsed plasma and related physical mechanism have been investigated. Thin film c-BN, Ti(CN), TiN, DLC and AlN materials have been produced successfully on various substrates at room temperature. A wide interface layer exists between film and substrate, resulting in strong adhesion. Metal surface properties can be improved greatly by using this kind of treatment

  6. Formation of Porous Structure with Subspot Size under the Irradiation of Picosecond Laser Pulses

    Directory of Open Access Journals (Sweden)

    Bin Liu

    2013-01-01

    Full Text Available A study was presented in this paper on porous structure with microsize holes significantly smaller than laser spot on the stainless steel 304 target surface induced by a picosecond Nd:van regenerative amplified laser, operating at 1064 nm. The target surface variations were studied in air ambience. The estimated surface damage threshold was 0.15 J/cm2. The target specific surface changes and phenomena observed supported a complementary study on the formation and growth of the subspot size pit holes on metal surface with dependence of laser pulse number of 50–1000 and fluences of 0.8 and 1.6 J/cm2. Two kinds of porous structures were presented: periodic holes are formed from Coulomb Explosion during locally spatial modulated ablation, and random holes are formed from the burst of bubbles in overheated liquid during phase explosion. It can be concluded that it is effective to fabricate a large metal surface area of porous structure by laser scanning regime. Generally, it is also difficult for ultrashort laser to fabricate the microporous structures compared with traditional methods. These porous structures potentially have a number of important applications in nanotechnology, industry, nuclear complex, and so forth.

  7. Irradiation effects in beryllium exposed to high energy protons of the NuMI neutrino source

    Energy Technology Data Exchange (ETDEWEB)

    Kuksenko, V., E-mail: viacheslav.kuksenko@materials.ox.ac.uk [University of Oxford, Oxford (United Kingdom); Ammigan, K.; Hartsell, B. [Fermi National Accelerator Laboratory, Batavia (United States); Densham, C. [Rutherford Appleton Laboratory, Didcot (United Kingdom); Hurh, P. [Fermi National Accelerator Laboratory, Batavia (United States); Roberts, S. [University of Oxford, Oxford (United Kingdom)

    2017-07-15

    A beryllium primary vacuum-to-air beam ‘window’ of the 'Neutrinos at the Main Injector' (NuMI) beamline at Fermi National Accelerator Laboratory (Fermilab), Batavia, Illinois, USA, has been irradiated by 120 GeV protons over 7 years, with a maximum integrated fluence at the window centre of 2.06 10{sup 22} p/cm{sup 2} corresponding to a radiation damage level of 0.48 dpa. The proton beam is pulsed at 0.5 Hz leading to an instantaneous temperature rise of 40 °C per pulse. The window is cooled by natural convection and is estimated to operate at an average of around 50 °C. The microstructure of this irradiated material was investigated by SEM/EBSD and Atom Probe Tomography, and compared to that of unirradiated regions of the beam window and that of stock material of the same PF-60 grade. Microstructural investigations revealed a highly inhomogeneous distribution of impurity elements in both unirradiated and irradiated conditions. Impurities were mainly localised in precipitates, and as segregations at grain boundary and dislocation lines. Low levels of Fe, Cu, Ni, C and O were also found to be homogeneously distributed in the beryllium matrix. In the irradiated materials, up to 440 appm of Li, derived from transmutation of beryllium was homogeneously distributed in solution in the beryllium matrix.

  8. INTERACTION OF LASER RADIATION WITH MATTER AND OTHER LASER APPLICATIONS: Changes in the emission properties of metal targets during pulse-periodic laser irradiation

    Science.gov (United States)

    Konov, Vitalii I.; Pimenov, S. M.; Prokhorov, A. M.; Chapliev, N. I.

    1988-02-01

    A scanning electron microscope was used with a pulse-periodic CO2 laser to discover the laws governing the correlation of the modified microrelief of metal surfaces, subjected to the action of multiple laser pulses, with the emission of charged particles and the luminescence of the irradiated zone. It was established that the influence of sorption and laser-induced desorption on the emission signals may be manifested differently depending on the regime of current generation in the "target-vacuum chamber" circuit.

  9. GaN thin films growth and their application in photocatalytic removal of sulforhodamine B from aqueous solution under UV pulsed laser irradiation.

    Science.gov (United States)

    Gondal, Mohammed A; Chang, Xiao F; Yamani, Zain H; Yang, Guo F; Ji, Guang B

    2011-01-01

    Single-crystalline Gallium Nitride (GaN) thin films were fabricated and grown by metal organic chemical vapor deposition (MOCVD) method on c-plane sapphire substrates and then characterized by high resolution-X-ray diffraction (HR-XRD) and photoluminescence (PL) measurements. The photocatalytic decomposition of Sulforhodamine B (SRB) molecules on GaN thin films was investigated under 355 nm pulsed UV laser irradiation. The results demonstrate that as-grown GaN thin films exhibited efficient degradation of SRB molecules and exhibited an excellent photocatalytic-activity-stability under UV pulsed laser exposure.

  10. Ion energy distributions in bipolar pulsed-dc discharges of methane measured at the biased cathode

    Energy Technology Data Exchange (ETDEWEB)

    Corbella, C; Rubio-Roy, M; Bertran, E; Portal, S; Pascual, E; Polo, M C; Andujar, J L, E-mail: corbella@ub.edu [FEMAN Group, IN2UB, Departament de Fisica Aplicada i Optica, Universitat de Barcelona, c/ MartI i Franques 1, 08028 Barcelona (Spain)

    2011-02-15

    The ion fluxes and ion energy distributions (IED) corresponding to discharges in methane (CH{sub 4}) were measured in time-averaged mode with a compact retarding field energy analyser (RFEA). The RFEA was placed on a biased electrode at room temperature, which was powered by either radiofrequency (13.56 MHz) or asymmetric bipolar pulsed-dc (250 kHz) signals. The shape of the resulting IED showed the relevant populations of ions bombarding the cathode at discharge parameters typical in the material processing technology: working pressures ranging from 1 to 10 Pa and cathode bias voltages between 100 and 200 V. High-energy peaks in the IED were detected at low pressures, whereas low-energy populations became progressively dominant at higher pressures. This effect is attributed to the transition from collisionless to collisional regimes of the cathode sheath as the pressure increases. On the other hand, pulsed-dc plasmas showed broader IED than RF discharges. This fact is connected to the different working frequencies and the intense peak voltages (up to 450 V) driven by the pulsed power supply. This work improves our understanding in plasma processes at the cathode level, which are of crucial importance for the growth and processing of materials requiring controlled ion bombardment. Examples of industrial applications with these requirements are plasma cleaning, ion etching processes during fabrication of microelectronic devices and plasma-enhanced chemical vapour deposition of hard coatings (diamond-like carbon, carbides and nitrides).

  11. A Summary of Recent Experimental Research on Ion Energy and Charge States of Pulsed Vacuum Arcs

    International Nuclear Information System (INIS)

    Oks, Efim M.; Yushkov, Georgy Yu.; Anders, Andre

    2008-01-01

    The paper reviews the results of vacuum arc experimental investigations made collaboratively by research groups from Berkeley and Tomsk over the last two years, i.e. since the last ISDEIV in 2006. Vacuum arc plasma of various metals was produced in pulses of a few hundred microseconds duration, and the research focused on three topics: (i) the energy distribution functions for different ion charge states, (ii) the temporal development of the ion charge state distribution, and (iii) the evolution of the mean directed ion velocities during plasma expansion. A combined quadruple mass-to-charge and energy analyzer (EQP by HIDEN Ltd) and a time-of-flight spectrometer were employed. Cross-checking data by those complimentary techniques helped to avoid possible pitfalls in interpretation. It was found that the ion energy distribution functions in the plasma were independent of the ion charge state, which implies that the energy distribution on a substrate are not equal to due to acceleration in the substrate's sheath. In pulsed arc mode, the individual ion charge states fractions showed changes leading to a decrease of the mean charge state toward a steady-state value. This decrease can be reduced by lower arc current, higher pulse repetition rate and reduced length of the discharge gap. It was also found that the directed ion velocity slightly decreased as the plasma expanded into vacuum

  12. Graphitic carbon nanospheres: A Raman spectroscopic investigation of thermal conductivity and morphological evolution by pulsed laser irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Agarwal, Radhe; Sahoo, Satyaprakash, E-mail: satya504@gmail.com, E-mail: rkatiyar@hpcf.upr.edu; Chitturi, Venkateswara Rao; Katiyar, Ram S., E-mail: satya504@gmail.com, E-mail: rkatiyar@hpcf.upr.edu [Department of Physics, University of Puerto Rico, San Juan, Puerto Rico 00936-8377 (United States)

    2015-12-07

    Graphitic carbon nanospheres (GCNSs) were prepared by a unique acidic treatment of multi-walled nanotubes. Spherical morphology with a narrow size distribution was confirmed by transmission electron microscopy studies. The room temperature Raman spectra showed a clear signature of D- and G-peaks at around 1350 and 1591 cm{sup −1}, respectively. Temperature dependent Raman scattering measurements were performed to understand the phonon dynamics and first order temperature coefficients related to the D- and G-peaks. The temperature dependent Raman spectra in a range of 83–473 K were analysed, where the D-peak was observed to show a red-shift with increasing temperature. The relative intensity ratio of D- to G-peaks also showed a significant rise with increasing temperature. Such a temperature dependent behaviour can be attributed to lengthening of the C-C bond due to thermal expansion in material. The estimated value of the thermal conductivity of GCNSs ∼0.97 W m{sup −1} K{sup −1} was calculated using Raman spectroscopy. In addition, the effect of pulsed laser treatment on the GCNSs was demonstrated by analyzing the Raman spectra of post irradiated samples.

  13. Mid-infrared source with 0.2 J pulse energy based on nonlinear conversion of Q-switched pulses in ZnGeP2.

    Science.gov (United States)

    Haakestad, Magnus W; Fonnum, Helge; Lippert, Espen

    2014-04-07

    Mid-infrared (3-5 μm) pulses with high energy are produced using nonlinear conversion in a ZnGeP(2)-based master oscillator-power amplifier, pumped by a Q-switched cryogenic Ho:YLF oscillator. The master oscillator is based on an optical parametric oscillator with a V-shaped 3-mirror ring resonator, and the power amplifier is based on optical parametric amplification in large-aperture ZnGeP(2) crystals. Pulses with up to 212 mJ energy at 1 Hz repetition rate are obtained, with FWHM duration 15 ns and beam quality M(2) = 3.

  14. Effects of high-energy electron irradiation of chicken meat on Salmonella and aerobic plate count

    International Nuclear Information System (INIS)

    Heath, J.L.; Owens, S.L.; Tesch, S.; Hannah, K.W.

    1990-01-01

    Four experiments were used to determine the effects of high-energy irradiation on the number of aerobic microorganisms and Salmonella on broiler breasts and thighs. Irradiation ranging from 100 to 700 kilorads (krads) was provided by a commercial-scale, electron-beam accelerator. Irradiation of broiler breast and thigh pieces with electron beams at levels of 100, 200, 300, 400, 500, and 600 krads showed that levels as low as 100 krads would eliminate Salmonella. When 33 thighs were tested after irradiation at 200 krads, only one thigh tested presumptive positive. The total number of aerobic organisms was reduced by 2 to 3 log10 cycles at irradiation levels of 100, 200, 300, 400, 500, 600, and 700 krads. Increasing the dose above 100 krads gave little if any additional benefit

  15. Parametric generation of high-energy 14.5-fs light pulses at 1.5 mum.

    Science.gov (United States)

    Nisoli, M; Stagira, S; De Silvestri, S; Svelto, O; Valiulis, G; Varanavicius, A

    1998-04-15

    High-energy light pulses that are tunable from 1.1 to 2.6 mum, with a duration as short as 14.5 fs were generated in a type II phase-matching beta-BaB(2)O(4) traveling-wave parametric converter pumped by 18-fs pulses obtained from a Ti:sapphire laser with chirped-pulse amplification, followed by a hollow-fiber compressor.

  16. LET effects of high energy ion beam irradiation on polysilanes

    Energy Technology Data Exchange (ETDEWEB)

    Seki, Shu; Kanzaki, Kenichi; Tagawa, Seiichi; Yoshida, Yoichi [Osaka Univ., Ibaraki (Japan). Inst. of Scientific and Industrial Research; Kudoh, Hisaaki; Sugimoto, Masaki; Sasuga, Tsuneo; Seguchi, Tadao; Shibata, Hiromi

    1997-03-01

    Thin films of poly(di-n-hexylsilane) were irradiated with 2-20 MeV H{sup +} and He{sup +} ion beams. The beams caused heterogeneous reactions of crosslinking and main chain scission in the films. The relative efficiency of the crosslinking was drastically changed in comparison with that of main chain scission. The anomalous change in the molecular weight distribution was analyzed with increasing irradiation fluence, and the ion beam induced reaction radius; track radius was determined for the radiation sources by the function of molecular weight dispersion. Obtained values were 59{+-}15 A and 14{+-}6 A for 2 MeV He{sup +} and 20 MeV H{sup +} ion beams respectively. (author)

  17. Fluence behavior of polyethylene films irradiated with high energy electrons

    International Nuclear Information System (INIS)

    Pino, Eddy Segura; Silva, Leonardo G. Andrade e

    1999-01-01

    Polymers are viscoelastic materials at all temperatures, so that mechanical loads induce time dependable deformations. The recovery of these deformations, on load release, take some time and it is not always recovered completely. The main objective of this work was to analyse the creep behavior of electron irradiated polyethylene films. From the experimental results, it was sated that polyethylene creeps less with an increase on irradiation dose and also that creep recovery in this material increases with doses but it is not complete. This behavior can be attributed to the crosslinking effect witch stabilize elements of the molecular structure of the polyethylene, thus reducing their mobility and so inhibiting the creep mechanism. The partial creep recovery could be also attributed to the reticulation effect and to the polyethylene plastic behavior. Additional information on the creep behavior was obtained by fitting the experimental data with exponential functions and evaluating the mathematical parameters with a modified Kelvin-Voigt mechanical model. (author)

  18. Radiation defects in InN irradiated with high-energy electrons

    International Nuclear Information System (INIS)

    Zhivul'ko, V.D.; Mudryj, A.V.; Yakushev, M.V.; Martin, R.; Shaff, V.; Lu, Kh.; Gurskij, A.L.

    2013-01-01

    The influence of high energy (6 MeV, fluencies 10 15 – 10 18 cm -2 ) electron irradiation on the fundamental absorption and luminescence properties of InN thin films which were grown on sapphire substrates by molecular bean epitaxial has been studied. It is found that electron irradiation increases the electron concentration and band gap energy E g of InN. The shift of the band gap energy E g is a manifestation of the Burshtein-Mossa effect. (authors)

  19. Low-energy electron irradiation induced top-surface nanocrystallization of amorphous carbon film

    Science.gov (United States)

    Chen, Cheng; Fan, Xue; Diao, Dongfeng

    2016-10-01

    We report a low-energy electron irradiation method to nanocrystallize the top-surface of amorphous carbon film in electron cyclotron resonance plasma system. The nanostructure evolution of the carbon film as a function of electron irradiation density and time was examined by transmission electron microscope (TEM) and Raman spectroscopy. The results showed that the electron irradiation gave rise to the formation of sp2 nanocrystallites in the film top-surface within 4 nm thickness. The formation of sp2 nanocrystallite was ascribed to the inelastic electron scattering in the top-surface of carbon film. The frictional property of low-energy electron irradiated film was measured by a pin-on-disk tribometer. The sp2 nanocrystallized top-surface induced a lower friction coefficient than that of the original pure amorphous film. This method enables a convenient nanocrystallization of amorphous surface.

  20. Recent Advancements in the Numerical Simulation of Surface Irradiance for Solar Energy Applications: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Yu; Sengupta, Manajit; Deline, Chris

    2017-06-27

    This paper briefly reviews the National Renewable Energy Laboratory's recent efforts on developing all-sky solar irradiance models for solar energy applications. The Fast All-sky Radiation Model for Solar applications (FARMS) utilizes the simulation of clear-sky transmittance and reflectance and a parameterization of cloud transmittance and reflectance to rapidly compute broadband irradiances on horizontal surfaces. FARMS delivers accuracy that is comparable to the two-stream approximation, but it is approximately 1,000 times faster. A FARMS-Narrowband Irradiance over Tilted surfaces (FARMS-NIT) has been developed to compute spectral irradiances on photovoltaic (PV) panels in 2002 wavelength bands. Further, FARMS-NIT has been extended for bifacial PV panels.

  1. SU-E-T-501: Normal Tissue Toxicities of Pulsed Low Dose Rate Radiotherapy and Conventional Radiotherapy: An in Vivo Total Body Irradiation Study

    Energy Technology Data Exchange (ETDEWEB)

    Cvetkovic, D; Zhang, P; Wang, B; Chen, L; Ma, C [Fox Chase Cancer Center, Philadelphia, PA (United States)

    2014-06-01

    Purpose: Pulsed low dose rate radiotherapy (PLDR) is a re-irradiation technique for therapy of recurrent cancers. We have previously shown a significant difference in the weight and survival time between the mice treated with conventional radiotherapy (CRT) and PLDR using total body irradiation (TBI). The purpose of this study was to investigate the in vivo effects of PLDR on normal mouse tissues.Materials and Methods: Twenty two male BALB/c nude mice, 4 months of age, were randomly assigned into a PLDR group (n=10), a CRT group (n=10), and a non-irradiated control group (n=2). The Siemens Artiste accelerator with 6 MV photon beams was used. The mice received a total of 18Gy in 3 fractions with a 20day interval. The CRT group received the 6Gy dose continuously at a dose rate of 300 MU/min. The PLDR group was irradiated with 0.2Gyx20 pulses with a 3min interval between the pulses. The mice were weighed thrice weekly and sacrificed 2 weeks after the last treatment. Brain, heart, lung, liver, spleen, gastrointestinal, urinary and reproductive organs, and sternal bone marrow were removed, formalin-fixed, paraffin-embedded and stained with H and E. Morphological changes were observed under a microscope. Results: Histopathological examination revealed atrophy in several irradiated organs. The degree of atrophy was mild to moderate in the PLDR group, but severe in the CRT group. The most pronounced morphological abnormalities were in the immune and hematopoietic systems, namely spleen and bone marrow. Brain hemorrhage was seen in the CRT group, but not in the PLDR group. Conclusions: Our results showed that PLDR induced less toxicity in the normal mouse tissues than conventional radiotherapy for the same dose and regimen. Considering that PLDR produces equivalent tumor control as conventional radiotherapy, it would be a good modality for treatment of recurrent cancers.

  2. Efficient production of NV colour centres in nanodiamonds using high-energy electron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Dantelle, G., E-mail: geraldine.dantelle@polytechnique.ed [Laboratoire de Physique Quantique et Moleculaire, ENS Cachan, 94 235 CACHAN Cedex (France); Laboratoire de Physique de la Matiere Condensee, Ecole Polytechnique, 91128 PALAISEAU Cedex (France); Slablab, A.; Rondin, L. [Laboratoire de Physique Quantique et Moleculaire, ENS Cachan, 94 235 CACHAN Cedex (France); Laine, F.; Carrel, F.; Bergonzo, Ph. [CEA-LIST, CEA/Saclay, 91 191 GIF-SUR-YVETTE Cedex (France); Perruchas, S.; Gacoin, T. [Laboratoire de Physique de la Matiere Condensee, Ecole Polytechnique, 91128 PALAISEAU Cedex (France); Treussart, F.; Roch, J.-F. [Laboratoire de Physique Quantique et Moleculaire, ENS Cachan, 94 235 CACHAN Cedex (France)

    2010-09-15

    Nanodiamond powders with an average size of 50 nm have been irradiated using high-energy electron beam. After annealing and chemical treatment, nanodiamond colloidal solutions were obtained and deposited on silica coverslips by spin-coating. The fluorescence of nanodiamonds was studied by confocal microscopy together with atomic force microscopy. We evaluated the proportion of luminescent nanodiamonds as a function of the irradiation duration and showed that large quantities, exceeding hundreds of mg, of luminescent nanodiamonds can be produced within 1 h of electron irradiation.

  3. Efficient production of NV colour centres in nanodiamonds using high-energy electron irradiation

    International Nuclear Information System (INIS)

    Dantelle, G.; Slablab, A.; Rondin, L.; Laine, F.; Carrel, F.; Bergonzo, Ph.; Perruchas, S.; Gacoin, T.; Treussart, F.; Roch, J.-F.

    2010-01-01

    Nanodiamond powders with an average size of 50 nm have been irradiated using high-energy electron beam. After annealing and chemical treatment, nanodiamond colloidal solutions were obtained and deposited on silica coverslips by spin-coating. The fluorescence of nanodiamonds was studied by confocal microscopy together with atomic force microscopy. We evaluated the proportion of luminescent nanodiamonds as a function of the irradiation duration and showed that large quantities, exceeding hundreds of mg, of luminescent nanodiamonds can be produced within 1 h of electron irradiation.

  4. Application of pulse power technology to ultra high energy electron accelerators

    International Nuclear Information System (INIS)

    Nation, J.A.

    1989-01-01

    The author presents in this paper a review of the application of pulse power technology to the development of high gradient electron accelerators. The technology demands are relatively modest compared to the ultra high power technology used for inertial confinement fusion drivers. With the advent of magnetic switching intense electron beams can be generated with a sufficiently high repetition rate to be of interest for high energy electron accelerator driver applications. Most of the techniques considered rely on the excitation of large amplitude waves on the beams. Within this framework there are two broad categories of accelerator, those in which the waves are directly excited in and supported by the medium and, secondly, those where the waves are used to generate radiofrequency signals which are then coupled via structures to the beam being accelerated. In what follows we shall consider both approaches. Present-day pulse power technology limits pulse durations to about 100 nsec. Consequently, if these sources are to be used, we will need to use high group velocity structures to avoid the need for short accelerator module lengths. An advantage of the short pulse duration is that the available acceleration voltage gradient increases compared to that obtained using conventional rf drivers. 19 references, 9 figures, 1 table

  5. Long-lived isotopes production in Pb-Bi target irradiated by high energy protons

    Energy Technology Data Exchange (ETDEWEB)

    Korovin, Y.A.; Konobeyev, A.Y.; Pereslavtsev, P.E. [Obninsk Institute of Nuclear Power Engineering, Obninsk (Russian Federation)

    1995-10-01

    Concentration of long-lived isotopes has been calculated for lead and lead-bismuth targets irradiated by protons with energy 0.4, 0.8, 1.0 and 1.6 GeV. The time of irradiation is equal from 1 month up to 2 years. The data libraries BROND, ADL and MENDL have been used to obtain the rate of nuclide transmutation. All calculations have been performed using the SNT code.

  6. Investigation of the fundamentals of low-energy nanosecond pulse ignition: Final CRADA Report

    Energy Technology Data Exchange (ETDEWEB)

    Wallner, Thomas [Argonne National Lab. (ANL), Argonne, IL (United States); Scarcelli, Riccardo [Argonne National Lab. (ANL), Argonne, IL (United States); Zhang, Anqi [Argonne National Lab. (ANL), Argonne, IL (United States); Sevik, James [Argonne National Lab. (ANL), Argonne, IL (United States); Biruduganti, Munidhar [Argonne National Lab. (ANL), Argonne, IL (United States); Bihari, Bipin [Argonne National Lab. (ANL), Argonne, IL (United States); Matusik, Katarzyna E. [Argonne National Lab. (ANL), Argonne, IL (United States); Duke, Daniel J. [Argonne National Lab. (ANL), Argonne, IL (United States); Powell, Christopher F. [Argonne National Lab. (ANL), Argonne, IL (United States); Kastengren, Alan L. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2017-01-01

    A detailed investigation of the fundamentals of low-energy nanosecond pulse ignition was performed with the objective to overcome the barrier presented by limited knowledge and characterization of nonequilibrium plasma ignition for realistic internal combustion engine applications (be it in the automotive or power generation field) and shed light on the mechanisms which improve the performance of the advanced TPS ignition system compared to conventional state-of-the-art hardware. Three main tasks of the research included experimental evaluation on a single-cylinder automotive gasoline engine, experimental evaluation on a single-cylinder stationary natural gas engine and energy quantification using x-ray diagnostics.

  7. Correlations between muons and low energy pulses at LSD of the Mont Blanc laboratory near the time of SN1987A explosion

    International Nuclear Information System (INIS)

    Dadykin, V.L.; Khalchukov, F.F.; Korchagin, P.V.; Korolkova, E.V.; Kudryavtsev, V.A.; Mal'gin, A.S.; Ryasny, V.G.; Ryazhskaya, O.G.; Yakushev, V.F.; Zatsepin, G.T.; Aglietta, M.; Badino, G.; Bologna, G.; Castagnoli, C.; Castellina, A.; Fulgione, W.; Galeotti, P.; Saavedra, O.; Trinchero, G.; Vernetto, S.; Turin Univ.

    1989-01-01

    We have analysed the data of LSD from February 10, 1987, to March 7, 1987, in order to search for autocorrelations between all pulses detected by LSD with energy higher than 5 MeV like those occurred at ∼ 3:00 UT on February 23, 1987, between the pulses detected by 3 neutrino telescopes and 2 gravitational wave antennae. We have found 9 pairs of correlated pulses (muon + low energy pulse) from 5:42 UT to 10:13 UT on February 23, 1987. The time differences of pulses in the pairs are less than 2 s, the first pulse in the pair being either muon or low energy pulse. The frequency of such random poissonian fluctuations is ∼1/(10 years). There are no correlations outside statistics between low energy, low energy pulses and muon, muon pulses detected by LSD during the whole time period

  8. Low energy helium ion irradiation induced nanostructure formation on tungsten surface

    International Nuclear Information System (INIS)

    Al-Ajlony, A.; Tripathi, J.K.; Hassanein, A.

    2017-01-01

    We report on the low energy helium ion irradiation induced surface morphology changes on tungsten (W) surfaces under extreme conditions. Surface morphology changes on W surfaces were monitored as a function of helium ion energy (140–300 eV), fluence (2.3 × 10 24 –1.6 × 10 25 ions m −2 ), and flux (2.0 × 10 20 –5.5 × 10 20 ion m −2 s −1 ). All the experiments were performed at 900° C. Our study shows significant effect of all the three ion irradiation parameters (ion flux, fluence, and energy) on the surface morphology. However, the effect of ion flux is more pronounced. Variation of helium ion fluence allows to capture the very early stages of fuzz growth. The observed fuzz growth and morphology changes were understood in the realm of various possible phenomena. The study has relevance and important impact in the current and future nuclear fusion applications. - Highlights: •Reporting formation of W nanostructure (fuzz) due to low energy He ion beam irradiation. •Observing the very early stages for the W-Fuzz formation. •Tracking the surface morphological evolution during the He irradiation. •Discussing in depth our observation and drawing a possible scenario that explain this phenomenon. •Studying various ions irradiation parameters such as flux, fluence, and ions energy.

  9. Low energy helium ion irradiation induced nanostructure formation on tungsten surface

    Energy Technology Data Exchange (ETDEWEB)

    Al-Ajlony, A., E-mail: montaserajlony@yahoo.com; Tripathi, J.K.; Hassanein, A.

    2017-05-15

    We report on the low energy helium ion irradiation induced surface morphology changes on tungsten (W) surfaces under extreme conditions. Surface morphology changes on W surfaces were monitored as a function of helium ion energy (140–300 eV), fluence (2.3 × 10{sup 24}–1.6 × 10{sup 25} ions m{sup −2}), and flux (2.0 × 10{sup 20}–5.5 × 10{sup 20} ion m{sup −2} s{sup −1}). All the experiments were performed at 900° C. Our study shows significant effect of all the three ion irradiation parameters (ion flux, fluence, and energy) on the surface morphology. However, the effect of ion flux is more pronounced. Variation of helium ion fluence allows to capture the very early stages of fuzz growth. The observed fuzz growth and morphology changes were understood in the realm of various possible phenomena. The study has relevance and important impact in the current and future nuclear fusion applications. - Highlights: •Reporting formation of W nanostructure (fuzz) due to low energy He ion beam irradiation. •Observing the very early stages for the W-Fuzz formation. •Tracking the surface morphological evolution during the He irradiation. •Discussing in depth our observation and drawing a possible scenario that explain this phenomenon. •Studying various ions irradiation parameters such as flux, fluence, and ions energy.

  10. A 16.3 pJ/pulse low-complexity and energy-efficient transmitter with adjustable pulse parameters

    International Nuclear Information System (INIS)

    Jiang Jun; Zhao Yi; Shao Ke; Chen Hu; Xia Lingli; Hong Zhiliang

    2011-01-01

    This paper presents a novel, fully integrated transmitter for 3-5 GHz pulsed UWB. The BPSK modulation transmitter has been implemented in SMIC CMOS 0.13 μm technology with a 1.2-V supply voltage and a die size of 0.8 x 0.95 mm 2 . This transmitter is based on the impulse response filter method, which uses a tunable R paralleled with a LC frequency selection network to realize continuously adjustable pulse parameters, including bandwidth, width and amplitude. Due to the extremely low duty of the pulsed UWB, a proposed output buffer is employed to save power consumption significantly. Finally, measurement results show that the transmitter consumes only 16.3 pJ/pulse to achieve a pulse repetition rate of 100 Mb/s. Generated pulses strictly comply with the FCC spectral mask. The continuously variable pulse width is from 900 to 1.5 ns and the amplitude with the minimum 178 mVpp and the maximum 432 mVpp can be achieved. (semiconductor integrated circuits)

  11. High power pulsed/microwave technologies for electron accelerators vis a vis 10MeV, 10kW electron LINAC for food irradiation at CAT

    International Nuclear Information System (INIS)

    Shrivastava, Purushottam; Mulchandani, J.; Mohania, P.; Baxy, D.; Wanmode, Y.; Hannurkar, P.R.

    2005-01-01

    Use of electron accelerators for irradiation of food items is gathering momentum in India. The various technologies for powering the electron LINAC were needed to be developed in the country due to embargo situations as well as reservations of the developers worldwide to share the information related to this development. Centre for Advanced Technology, CAT, Indore, is engaged in the development of particle accelerators for medical industrial and scientific applications. Amongst other electron accelerators developed in CAT, a 10MeV, 10kW LINAC for irradiation of food items has been commissioned and tested for full rated 10kW beam power. The high power pulsed microwave driver for the LINAC was designed, developed and commissioned with full indigenous efforts, and is right now operational at CAT. It consists of a 6MW, 25kW S-band pulsed klystron, 15MW peak power pulse modulator system for the klystron, microwave driver amplifier chain, stabilized generator, protection and control electronics, waveguide system to handle the high peak and average power, gun modulator electronics, grid electronics etc. The present paper highlights various technologies like the pulsed power systems and components, microwave circuits and systems etc. Also the performance results of the high power microwave driver for the 10MeV LINAC at CAT are discussed. Future strategies for developing the state of art technologies are highlighted. (author)

  12. Design, Construction and Testing of a Pulsed High Energy Inductive Superconducting Energy Storage System

    Science.gov (United States)

    1975-09-01

    10,000 tim;es larger tnan the resistive voltaje and can be !-½vce evough to de;tr,)y electronic equip-ient. This task car. be accu)rplmshrd by...2.67 kH. FA 2483 231 E cNu 42 1 o Time 0.2 ms/cm Figure 128 Single pulse of current to 0.2 2 load delivered by helium switch. Firingj voltaj - 2,000 V

  13. Energy balance and efficiency of power stations with a pulsed Tokamak reactor

    International Nuclear Information System (INIS)

    Davenport, P.A.; Mitchell, J.T.D.; Darvas, J.; Foerster, S.; Sack, B.

    1976-06-01

    The energy balance of a fusion power station based on the TOKAMAK concept is examined with the aid of a model comprising three distinct elements: the reactor, the energy converter and the reactor operation equipment. The efficiency of each element is expressed in terms of the various energy flows and the product of these efficiencies gives the net station efficiency. The analysis takes account of pulsed operation and has general applicability. Numerical values for the net station efficiency are derived from detailed estimates of the energy flows for a TOKAMAK reactor and its auxiliary equipment operating with advanced energy converters. The derivation of these estimates is given in eleven appendices. The calculated station efficiencies span ranges similar to those quoted for the current generation of fission reactors, though lower than those predicted for HTGR and LMFBR stations. Credible parameter domains for pulsed TOKAMAK operation are firmly delineated and factors inimical to improved performance are indicated. It is concluded that the net thermal efficiency of a TOKAMAK reactor power station based on present designs and using advanced thermal converters will be approximately 0.3 and is unlikely to exceed 0.33. (orig.) [de

  14. Femtosecond laser-induced cross-periodic structures on a crystalline silicon surface under low pulse number irradiation

    Science.gov (United States)

    Ji, Xu; Jiang, Lan; Li, Xiaowei; Han, Weina; Liu, Yang; Wang, Andong; Lu, Yongfeng

    2015-01-01

    A cross-patterned surface periodic structure in femtosecond laser processing of crystalline silicon was revealed under a relatively low shots (4 energy slightly higher than the ablation threshold. The experimental results indicated that the cross-pattern was composed of mutually orthogonal periodic structures (ripples). Ripples with a direction perpendicular to laser polarization (R⊥) spread in the whole laser-modified region, with the periodicity around 780 nm which was close to the central wavelength of the laser. Other ripples with a direction parallel to laser polarization (R‖) were found to be distributed between two of the adjacent ripples R⊥, with a periodicity about the sub-wavelength of the irradiated laser, 390 nm. The geometrical morphology of two mutually orthogonal ripples under static femtosecond laser irradiation could be continuously rotated as the polarization directions changed, but the periodicity remained almost unchanged. The underlying physical mechanism was revealed by numerical simulations based on the finite element method. It was found that the incubation effect with multiple shots, together with the redistributed electric field after initial ablation, plays a crucial role in the generation of the cross-patterned periodic surface structures.

  15. The use of atomic energy for the irradiation of foods

    International Nuclear Information System (INIS)

    Wills, P.A.

    1982-01-01

    Radiation processing is a highly versatile preservation technique for the food industry. It is a cold treatment which can inhibit sprouting, eliminate insects and food pathogens, extend shelf life, decontaminate raw materials, and pasteurise or sterilise food and packaging materials. Recent developments, such as an International Standard for Irradiated Foods and a Code of Practice for the Operation of Radiation Facilities for the Treatment of Foods, are expected to stimulate and facilitate trade in radiation processed foods. These developments and prospects for commercialisation of this new technology in Australia are discussed

  16. Influence of plasma-induced energy deposition effects, the equation of state, thermal ionization, pulse shaping, and radiation on ion-beam-driven expansions of plane metal targets

    International Nuclear Information System (INIS)

    Long, K.A.; Tahir, N.A.

    1986-01-01

    In a previous paper by Long and Tahir [Phys. Fluids 29, 275 (1986)], the motion of plane targets irradiated by ion beams whose energy deposition was assumed to be independent of the ion energy, and the temperature and density of the plasma, was analyzed. In this paper, the analytic solution is extended in order to include the effects of a temperature-and density-dependent energy deposition as a result of electron excitation, an improved equation of state, thermal ionization, a pulse shape, and radiation losses. The change in the energy deposition with temperature and density leads to range shortening and an increased power deposition in the target. It is shown how the analytic theory can be used to analyze experiments to measure the enhanced energy deposition. In order to further analyze experiments, numerical simulations are presented which include the plasma-induced effects on the energy deposition. It is shown that since the change in the range is due to both decrease in density and the increase in temperature, it is not possible to separate these two effects in present experiments. Therefore, the experiments which measure the time-dependent energy of the ions emerging from the back side of a plane target do not as yet measure the energy loss as a function of the density and temperature of the plasma or of the energy of the ion, but only an averaged loss over certain ranges of these physical quantities

  17. High dose radiation damage in nuclear energy structural materials investigated by heavy ion irradiation simulation

    International Nuclear Information System (INIS)

    Zheng Yongnan; Xu Yongjun; Yuan Daqing

    2014-01-01

    Structural materials in ITER, ADS and fast reactor suffer high dose irradiations of neutrons and/or protons, that leads to severe displacement damage up to lOO dpa per year. Investigation of radiation damage induced by such a high dose irradiation has attracted great attention along with the development of nuclear energy facilities of new generation. However, it is deeply hampered for the lacking of high dose neutron and proton sources. Irradiation simulation of heavy ions produced by accelerators opens up an effective way for laboratory investigation of high dose irradiation induced radiation damage encountered in the ITER, ADS, etc. Radiation damage is caused mainly by atomic displacement in materials. The displacement rate of heavy ions is about lO 3 ∼10 7 orders higher than those of neutrons and protons. High displacement rate of heavy ions significantly reduces the irradiation time. The heavy ion irradiation simulation technique (HIIS) technique has been developed at China Institute of Atomic Energy and a series of the HIIS experiments have been performed to investigate radiation damage in stainless steels, tungsten and tantalum at irradiation temperatures from room temperature to 800 ℃ and in the irradiation dose region up to 100 dpa. The experimental results show that he radiation swelling peak for the modified stainless steel appears in the temperature region around 580 ℃ and the radiation damage is more sensitive to the temperature, the size of the radiation induced vacancy cluster or void increase with the increasing of the irradiation dose, and among the three materials the home-made modified stainless steel has the best radiation resistant property. (authors)

  18. Production of nanodiamonds by high-energy ion irradiation of graphite at room temperature

    International Nuclear Information System (INIS)

    Daulton, T.L.; Kirk, M.A.; Lewis, R.S.; Rehn, L.E.

    2001-01-01

    It has previously been shown that graphite can be transformed into diamond by MeV electron and ion irradiation at temperatures above approximately 600 deg. C. However, there exists geological evidence suggesting that carbonaceous materials can be transformed to diamond by irradiation at substantially lower temperatures. For example, submicron-size diamond aggregates have been found in uranium-rich, Precambrian carbonaceous deposits that never experienced high temperature or pressure. To test if diamonds can be formed at lower irradiation temperatures, sheets of fine-grain polycrystalline graphite were bombarded at 20 deg. C with 350±50 MeV Kr ions to fluences of 6x10 12 cm -2 using the Argonne tandem linear accelerator system (ATLAS). Ion-irradiated (and unirradiated control) graphite specimens were then subjected to acid dissolution treatments to remove untransformed graphite and isolate diamonds that were produced; these acid residues were subsequently characterized by high-resolution and analytical electron microscopy. The acid residue of the ion-irradiated graphite was found to contain nanodiamonds, demonstrating that ion irradiation of graphite at ambient temperature can produce diamond. The diamond yield under our irradiation conditions is low, ∼0.01 diamonds/ion. An important observation that emerges from comparing the present result with previous observations of diamond formation during irradiation is that nanodiamonds form under a surprisingly wide range of irradiation conditions. This propensity may be related to the very small difference in the graphite and diamond free-energies coupled with surface-energy considerations that may alter the relative stability of diamond and graphite at nanometer sizes

  19. Schlieren Visualization of the Energy Addition by Multi Laser Pulse in Hypersonic Flow

    International Nuclear Information System (INIS)

    Oliveira, A. C.; Minucci, M. A. S.; Toro, P. G. P.; Chanes, J. B. Jr; Myrabo, L. N.

    2008-01-01

    The experimental results of the energy addition by multi laser pulse in Mach 7 hypersonic flow are presented. Two high power pulsed CO 2 TEA lasers (TEA1 5.5 J, TEA2 3.9 J) were assembled sharing the same optical cavity to generate the plasma upstream of a hemispherical model installed in the tunnel test section. The lasers can be triggered with a selectable time delay and in the present report the results obtained with delay between 30 μs and 80 μs are shown. The schlieren technique associated with a high speed camera was used to accomplish the influence of the energy addition in the mitigation of the shock wave formed on the model surface by the hypersonic flow. A piezoelectric pressure transducer was used to obtain the time history of the impact pressure at stagnation point of the model and the pressure reduction could be measured. The total recovery of the shock wave between pulses as well as the prolonged effect of the mitigation without recovery was observed by changing the delay

  20. Healing of damaged metal by a pulsed high-energy electromagnetic field

    Science.gov (United States)

    Kukudzhanov, K. V.; Levitin, A. L.

    2018-04-01

    The processes of defect (intergranular micro-cracks) transformation are investigated for metal samples in a high-energy short-pulsed electromagnetic field. This investigation is based on a numerical coupled model of the impact of high-energy electromagnetic field on the pre-damaged thermal elastic-plastic material with defects. The model takes into account the melting and evaporation of the metal and the dependence of its physical and mechanical properties on the temperature. The system of equations is solved numerically by finite element method with an adaptive mesh using the arbitrary Euler–Lagrange method. The calculations show that the welding of the crack and the healing of micro-defects under treatment by short pulses of the current takes place. For the macroscopic description of the healing process, the healing and damage parameters of the material are introduced. The healing of micro-cracks improves the material healing parameter and reduces its damage. The micro-crack shapes practically do not affect the time-dependence of the healing and damage under the treatment by the current pulses. These changes are affected only by the value of the initial damage of the material and the initial length of the micro-crack. The time-dependence of the healing and the damage is practically the same for all different shapes of micro-defects, provided that the initial lengths of micro-cracks and the initial damages are the same for these different shapes of defects.

  1. Er,Cr:YSGG Laser Energy Delivery: Pulse and Power Effects on Enamel Surface and Erosive Resistance.

    Science.gov (United States)

    de Oliveira, Renan Mota; de Souza, Vinicius Matsuzaki; Esteves, Camila Machado; de Oliveira Lima-Arsati, Ynara Bosco; Cassoni, Alessandra; Rodrigues, José Augusto; Brugnera Junior, Aldo

    2017-11-01

    High power lasers have been suggested as a useful tool for dental caries and erosion prevention due to the increase of enamel acid resistance. to evaluate the effect of Er,Cr:YSGG (erbium,chromium:yttrium, scandium, gallium, garnet) laser irradiation pulse frequency and power on enamel surface and acid erosion resistance. By combining pulse frequency (5-75 Hz) and power settings (0.10-1.00 W), 20 irradiated groups and one nonirradiated control group were tested. A total of 63 bovine enamel blocks (n = 3/group) were prepared for surface hardness and roughness evaluation, performed in three phases: baseline, after irradiation, and after erosive challenge. Enamel blocks were irradiated with Er,Cr:YSGG laser with MZ8 tip (iPlus; Waterlase, Biolase, CA) for 30 sec according to experimental group and submitted. Erosive challenge consisted of four cycles alternating immersion in 0.01 M HCl (5 mL/mm 2 ; 2 min; at 37°C) and immersion in artificial saliva for 3 h. Analysis of variance (three-way ANOVA), Tukey's test, and Pearson correlation were performed for the statistical analysis (p hardness. After erosive challenge, 5 and 75 W groups showed increase in surface hardness; 0.25, 0.5, 0.75, and 1 W groups showed minor alterations in surface roughness. the irradiation of Er,Cr:YSGG laser with different parameters of power and pulse frequency settings may alter enamel surface and erosive resistance differently. Pulse frequency of 30 Hz and power of 0.50 W was considered the best parameter to prevent enamel acid erosion.

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

    International Nuclear Information System (INIS)

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

    2004-01-01

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

  3. High-energy xenon ion irradiation effects on the electrical properties of yttrium iron garnet

    International Nuclear Information System (INIS)

    Costantini, J.M.; Flament, J.L.; Sinopoli, L.; Trochon, J.; Uzureau, J.L.; Groult, D.; Studer, F.; Toulemonde, M.

    1989-01-01

    Thin monocristalline samples of yttrium iron garnet Y 3 Fe 5 O 12 (YIG) were irradiated at room temperature with 27 MeV/A 132 Xe ions at varying fluences up to 3.5 x 10 12 ions cm -2 . Sample thickness (100 μm) was smaller than the mean projected range of ions (170 μm) so that we were able to study the effects of irradiation damage solely. At such a high ion energy the nuclear energy loss is negligible and damage is mainly due to electronic excitation energy loss. YIG d.c conductivity is found to rise by a factor 40 for the highest dose while the permittivity increases only slightly after irradiation (40% max.). The dielectric losses are also enhanced as the ion fluence increases especially at lower frequencies (by a factor 6 at 10 KHz). No dielectric relaxation peak is observed in the frequency range explored here (10 KHz - 10 MHz)

  4. Corrosion behaviour of AISI 304 stainless steel subjected to massive laser shock peening impacts with different pulse energies

    International Nuclear Information System (INIS)

    Lu, J.Z.; Qi, H.; Luo, K.Y.; Luo, M.; Cheng, X.N.

    2014-01-01

    Highlights: •Laser shock peening caused an obvious increase of corrosion resistance of 304 steel. •Corrosion resistance of stainless steel increased with increasing pulse energy. •Mechanism of laser shock peening on corrosion behaviour was also entirely determined. -- Abstract: Effects of massive laser shock peening (LSP) impacts with different pulse energies on ultimate tensile strength (UTS), stress corrosion cracking (SCC) susceptibility, fracture appearance and electrochemical corrosion resistance of AISI 304 stainless steel were investigated by slow strain rate test, potentiodynamic polarisation test and scanning electron microscope observation. The influence mechanism of massive LSP impacts with different pulse energies on corrosion behaviour was also determined. Results showed that massive LSP impacts effectively caused a significant improvement on UTS, SCC resistance, and electrochemical corrosion resistance of AISI 304 stainless steel. Increased pulse energy can also gradually improve its corrosion resistance

  5. Investigation of structural materials of reactors using high-energy heavy-ion irradiations

    International Nuclear Information System (INIS)

    Wang Zhiguang

    2007-01-01

    Radiation damage in structural materials of fission/fusion reactors is mainly attributed to the evolution of intensive atom displacement damage induced by energetic particles (n, α and/or fission fragments) and high-rate helium doping by direct α particle bombardments and/or (n, α) reactions. It can cause severe degradation of reactor structural materials such as surface blistering, bulk void swelling, deformation, fatigue, embrittlement, stress erosion corrosion and so on that will significantly affect the operation safety of reactors. However, up to now, behavior of structural materials at the end of their service can hardly be fully tested in a real reactor. In the present work, damage process in reactor structural materials is briefly introduced, then the advantages of energetic ion implantation/irradiation especially high-energy heavy ion irradiation are discussed, and several typical examples on simulation of radiation effects in reactor candidate structural materials using high-energy heavy ion irradiations are pronounced. Experimental results and theoretical analysis suggested that irradiation with energetic particles especially high-energy heavy ions is very useful technique for simulating the evolution of microstructures and macro-properties of reactor structural materials. Furthermore, an on-going plan of material irradiation experiments using high energy H- and He-ions based on the Heavy Ion Research Facilities in Lanzhou (HIRFL) is also briefly interpreted. (authors)

  6. Heat pulse analysis in JET and relation to local energy transport models

    International Nuclear Information System (INIS)

    Haas, J.C.M. de; Lopes Cardozo, N.J.; Han, W.; Sack, C.; Taroni, A.

    1989-01-01

    The evolution of a perturbation T e of the electron temperature depends on the linearised expression of the heat flux q e and may be not simply related to the local value of the electron heat conductivity χ e . It is possible that local heat transport models predicting similar temperature profiles and global energy confinement properties, imply a different propagation of heat pulses. We investigate here this possibility for the case of two models developed at JET. We also present results obtained at JET on a set of discharges covering the range of currents from 2 to 5 MA. Only L-modes, limiter discharges are considered here. Experimental results on the scaling of χ HP , the value of χ e related to heat pulse propagation, are compared with those of χ HP derived from the models. (author) 7 refs., 2 figs., 2 tabs

  7. Monitoring system of energy characteristics of electron beam during shaping process of power bremsstrahlung pulses

    International Nuclear Information System (INIS)

    Mordasov, N.G.; Ulimov, V.N.; Bryksin, V.A.; Shiyan, V.D.

    2005-01-01

    One proposes a procedure and a device to monitor dynamic and integral characteristics of electron power beams of high-current pulsed accelerators (HCPA) operating under Bremsstrahlung radiation mode. One obtained static and dynamic transfer characteristics for various types of heterogenous targets-converters under operation of UIN-10 HCPA with up to 4 MeV energy electrons, up to 60 kA current and 6 x 10 -8 -2 x 10 -6 s pulse efficient duration. One demonstrated the capabilities of the complex diagnostics of acceleration of electron beams by HCPA with simultaneous determination of parameters of the Bremsstrahlung radiation at the local point of the field behind the target-converter [ru

  8. Principles for construction of control and stabilization systems for pulse energy sources on the base of compression generators

    International Nuclear Information System (INIS)

    Abdukaev, I.Kh.; Kuchinskij, V.G.; Titov, V.I.

    1984-01-01

    Principles of construction of control and stabilization systems for a compression-generator (CG)-sources of power energy pulses- are considered. CG is an electromechanical energy converter, the principle of its operation is based on magnetic flux compression with periodic change of mutual inductance of two rotating windings. In each period, with the decrease of intrinsic inductance the generator forms in the load the pulse leading edge, and in the phase rise a pulse decay. To obtain the same pulse in the following period it is neccessary that the magnetic flux initial value should be restored in the generator winding. Problems of attaining pule shaper amplitude stability are considered. The method of pulse amplitude control in the load at the expense of the change in switch moment of capacitive storage to CG windings is suggested. The block-diagram of stabilization system is presented and its operation principle is described. The control system is assembled using K 155 and K 511 microcircuits and it was tested with CG at the pulse energy to 10 kJ. The tests have shown, that already to the third pulse the system provided quite shaped series of pulses

  9. Development of a high energy pulsed plasma simulator for the study of liquid lithium trenches

    International Nuclear Information System (INIS)

    Jung, S.; Christenson, M.; Curreli, D.; Bryniarski, C.; Andruczyk, D.; Ruzic, D.N.

    2014-01-01

    Highlights: • A pulse device for a liquid lithium trench study is developed. • It consists of a coaxial plasma gun, a theta pinch, and guiding magnets. • A large energy enhancement is observed with the use of the plasma gun. • A further increase in energy and velocity is observed with the theta pinch. - Abstract: To simulate detrimental events in a tokamak and provide a test-stand for a liquid-lithium infused trench (LiMIT) device [1], a pulsed plasma source utilizing a theta pinch in conjunction with a coaxial plasma accelerator has been developed. The plasma is characterized using a triple Langmuir probe, optical methods, and a calorimeter. Clear advantages have been observed with the application of a coaxial plasma accelerator as a pre-ionization source. The experimental results of the plasma gun in conjunction with the existing theta pinch show a significant improvement from the previous energy deposition by a factor of 14 or higher, resulting in a maximum energy and heat flux of 0.065 ± 0.002 MJ/m 2 and 0.43 ± 0.01 GW/m 2 . A few ways to further increase the plasma heat flux for LiMIT experiments are discussed

  10. New circuits high-voltage pulse generators with inductive-capacitive energy storage

    International Nuclear Information System (INIS)

    Gordeev, V.S.; Myskov, G.A.

    2001-01-01

    The paper describes new electric circuits of multi-cascade generators based on stepped lines. The distinction of the presented circuits consists in initial storage of energy in electric and magnetic fields simultaneously. The circuit of each generator,relations of impedances,values of initial current and charge voltages are selected in such a manner that the whole of initially stored energy is concentrated at the generator output as a result of transient wave processes. In ideal case the energy is transferred with 100% efficiency to the resistive load where a rectangular voltage pulse is formed, whose duration is equals to the double electrical length of the individual cascade. At the same time there is realized a several time increase of output voltage as compared to the charge voltage of the generator. The use of the circuits proposed makes it possible to ensure a several time increase (as compared to the selection of the number of cascades) of the generator energy storage, pulse current and output electric power

  11. Optimal design of waveform digitisers for both energy resolution and pulse shape discrimination

    Science.gov (United States)

    Cang, Jirong; Xue, Tao; Zeng, Ming; Zeng, Zhi; Ma, Hao; Cheng, Jianping; Liu, Yinong

    2018-04-01

    Fast digitisers and digital pulse processing have been widely used for spectral application and pulse shape discrimination (PSD) owing to their advantages in terms of compactness, higher trigger rates, offline analysis, etc. Meanwhile, the noise of readout electronics is usually trivial for organic, plastic, or liquid scintillator with PSD ability because of their poor intrinsic energy resolution. However, LaBr3(Ce) has been widely used for its excellent energy resolution and has been proven to have PSD ability for alpha/gamma particles. Therefore, designing a digital acquisition system for such scintillators as LaBr3(Ce) with both optimal energy resolution and promising PSD ability is worthwhile. Several experimental research studies about the choice of digitiser properties for liquid scintillators have already been conducted in terms of the sampling rate and vertical resolution. Quantitative analysis on the influence of waveform digitisers, that is, fast amplifier (optional), sampling rates, and vertical resolution, on both applications is still lacking. The present paper provides quantitative analysis of these factors and, hence, general rules about the optimal design of digitisers for both energy resolution and PSD application according to the noise analysis of time-variant gated charge integration.

  12. Development of a high energy pulsed plasma simulator for the study of liquid lithium trenches

    Energy Technology Data Exchange (ETDEWEB)

    Jung, S., E-mail: jung73@illinois.edu [Department of Nuclear, Plasma, and Radiological Engineering, University of Illinois at Urbana-Champaign, Urbana 61801 (United States); Christenson, M.; Curreli, D. [Department of Nuclear, Plasma, and Radiological Engineering, University of Illinois at Urbana-Champaign, Urbana 61801 (United States); Bryniarski, C. [Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana 61801 (United States); Andruczyk, D.; Ruzic, D.N. [Department of Nuclear, Plasma, and Radiological Engineering, University of Illinois at Urbana-Champaign, Urbana 61801 (United States)

    2014-12-15

    Highlights: • A pulse device for a liquid lithium trench study is developed. • It consists of a coaxial plasma gun, a theta pinch, and guiding magnets. • A large energy enhancement is observed with the use of the plasma gun. • A further increase in energy and velocity is observed with the theta pinch. - Abstract: To simulate detrimental events in a tokamak and provide a test-stand for a liquid-lithium infused trench (LiMIT) device [1], a pulsed plasma source utilizing a theta pinch in conjunction with a coaxial plasma accelerator has been developed. The plasma is characterized using a triple Langmuir probe, optical methods, and a calorimeter. Clear advantages have been observed with the application of a coaxial plasma accelerator as a pre-ionization source. The experimental results of the plasma gun in conjunction with the existing theta pinch show a significant improvement from the previous energy deposition by a factor of 14 or higher, resulting in a maximum energy and heat flux of 0.065 ± 0.002 MJ/m{sup 2} and 0.43 ± 0.01 GW/m{sup 2}. A few ways to further increase the plasma heat flux for LiMIT experiments are discussed.

  13. Long-Pulse Operation and High-Energy Particle Confinement Study in ICRF Heating of LHD

    International Nuclear Information System (INIS)

    Mutoh, Takashi; Kumazawa, Ryuhei; Seki, Tetsuo

    2004-01-01

    Long-pulse operation and high-energy particle confinement properties were studied using ion cyclotron range of frequency (ICRF) heating for the Large Helical Device. For the minority-ion mode, ions with energies up to 500 keV were observed by concentrating the ICRF heating power near the plasma axis. The confinement of high-energy particles was studied using the power-modulation technique. This confirmed that the confinement of high-energy particles was better with the inward-shifted configuration than with the normal configuration. This behavior was the same for bulk plasma confinement. Long-pulse operation for more than 2 min was achieved during the experimental program in 2002. This was mainly due to better confinement of the helically trapped particles and accumulation of fewer impurities in the region of the plasma core, in conjunction with substantial hardware improvements. Currently, the plasma operation time is limited by an unexpected density rise due to outgassing from the chamber materials. The temperature of the local carbon plates of the divertor exceeded 400 deg, C, and a charge-coupled device camera observed the hot spots. The hot spot pattern was well explained by a calculation of the accelerated-particle orbits, and those accelerated particles came from outside the plasma near the ICRF antenna

  14. Energy calibration of CsI(Tl) scintillator in pulse-shape identification technique

    CERN Document Server

    Avdeichikov, V; Golubev, P; Jakobsson, B; Colonna, N

    2003-01-01

    A batch of 16 CsI(Tl) scintillator crystals, supplied by the Bicron Company, has been studied with respect to precise energy calibration in pulse-shape identification technique. The light corresponding to pulse integration within the time interval 1.6-4.5 mu s (long gate) and 0.0-4.5 mu s (extra-long gate) exhibits a power law relation, L(E,Z,A)=a1(Z,A)E sup a sup 2 sup ( sup Z sup , sup A sup ) , for sup 1 sup , sup 2 sup , sup 3 H isotopes in the measured energy range 5-150 MeV. For the time interval 0.0-0.60 mu s (short gate), a significant deviation from the power law relation is observed, for energy greater than approx 30 MeV. The character of the a2(p)-a2(d) and a2(p)-a2(t) correlations for protons, deuterons and tritons, reveals 3 types of crystals in the batch. These subbatches differ in the value of the extracted parameter a2 for protons, and in the value of the spread of a2 for deuterons and tritons. This may be explained by the difference in the energy dependence of the fast decay time component an...

  15. High-energy chemical processes: Laser irradiation of aromatic hydrocarbons

    International Nuclear Information System (INIS)

    Trifunac, A.D.; Liu, A.D.; Loffredo, D.M.

    1994-01-01

    Recent studies of the high-energy photochemical degradation of polycyclic aromatic hydrocarbons (PAHs) in solution have furthered our fundamental understanding of the way in which radiation interacts with matter. A new comprehensive mechanism that unifies many of the seemingly contradictory observations in radiation and photochemistry has been proposed on basis of evidence gathered using specialized techniques such as transient optical spectroscopy and transient dc conductivity. The PAH molecules were activated by two-photon ionization, and behavior of the transient ions were monitored as a function of photon energy. It was found that a greater percentage of ions retain sufficient energy to decompose when higher energy light was used. When these cations decompose they leave a trail of products that establish a ''high-energy'' decomposition pathway that involves proton transfer from the ion, a mechanism hitherto not considered in photoionization processes

  16. Study of phonon-induced energy transfer processes in crystals using heat pulses

    International Nuclear Information System (INIS)

    Burns, A.R.

    1978-03-01

    The artificial generation of acoustic lattice vibrations by a heat pulse technique is developed in order to probe phonon interactions in molecular crystals. Specifically, the phonon-assisted delocalization of ''trapped'' excited triplet state energy in the aromatic crystal 1,2,4,5-tetrachlorobenzene (TCB) is studied in a quantitative manner by monitoring the time-resolved decrease in trap phosphorescence intensity due to the propagation of a well-defined heat pulse. The excitation distribution in a single trap system, such as the X-trap in neat h 2 -TCB, is discussed in terms of the energy partition function relating the temperature dependence of the trap phosphorescence intensity to the trap depth, exciton bandwidth, and the number of exciton band states. In a multiple trap system, such as the hd and h 2 isotopic traps in d 2 -TCB, the excitation distribution is distinctly non-Boltzmann; yet it may be discussed in terms of a preferential energy transfer between the two trap states via the exciton band. For both trap systems, a previously developed kinetic model is presented which relates the efficiency of trap-band energy exchange to the density of band states and the trap-phonon coupling matrix elements. A bolometric technique for determining the thermal response time of the heater/crystal system is presented. The phonon mean free path in the crystal is size-limited, and the heater/crystal boundary conductance is reasonably close to previously reported values. The theory of heat pulse phonon spectroscopy is presented and discussed in terms of black-body phonon radiation

  17. Defects in CdSe thin films, induced by high energy electron irradiation

    International Nuclear Information System (INIS)

    Ion, L.; Antohe, S.; Tutuc, D.; Antohe, V.A.; Tazlaoanu, C.

    2004-01-01

    Defects induced in CdSe thin films by high energy electron irradiation are investigated by means of thermally stimulated currents (TSC) spectroscopy. Films were obtained by vacuum deposition from a single source and irradiated with a 5 x 10 13 electrons/cm 2 s -1 beam of 6-MeV energy. It was found that electrical properties of the films are controlled by a deep donor state, located at 0.38 eV below the bottom edge of the conduction band. Parameters of the traps responsible for the recorded TSC peaks were determined. (authors)

  18. Hardness enhancement and crosslinking mechanisms in polystyrene irradiated with high energy ion-beams

    International Nuclear Information System (INIS)

    Lee, E.H.; Rao, G.R.; Mansur, L.K.

    1996-01-01

    Surface hardness values several times larger than steel were produced using high energy ion beams at several hundred keV to MeV. High LET is important for crosslinking. Crosslinking is studied by analyzing hardness variations in response to irradiation parameter such as ion species, energy, and fluence. Effective crosslinking radii at hardness saturation are derived base on experimental data for 350 keV H + and 1 MeV Ar + irradiation of polystyrene. Saturation value for surface hardness is about 20 GPa

  19. Simulation of ablation and plume dynamics under femtosecond double-pulse laser irradiation of aluminum: Comparison of atomistic and continual approaches

    Energy Technology Data Exchange (ETDEWEB)

    Fokin, Vladimir B.; Povarnitsyn, Mikhail E., E-mail: povar@ihed.ras; Levashov, Pavel R.

    2017-02-28

    Highlights: • We model double-pulse laser ablation of aluminum using microscopic and macroscopic approaches. • Both methods show decrease in depth of crater with increasing delay between pulses. • Both methods reveal the plume temperature growth with the increasing delay. • Good agreement between results is a step towards the development of combined model. - Abstract: We elaborated two numerical methods, two-temperature hydrodynamics and hybrid two-temperature molecular dynamics, which take into account basic mechanisms of a metal target response to ultrashort laser irradiation. The model used for the description of the electronic subsystem is identical for both approaches, while the ionic part is defined by an equation of state in hydrodynamics and by an interatomic potential in molecular dynamics. Since the phase diagram of the equation of state and corresponding potential match reasonably well, the dynamics of laser ablation obtained by both methods is quite similar. This correspondence can be considered as a first step towards the development of a self-consistent combined model. Two important processes are highlighted in simulations of double-pulse ablation: (1) the crater depth decrease as a result of recoil flux formation in the nascent plume when the delay between the pulses increases; (2) the plume reheating by the second pulse that gives rise to two- three-fold growth of the electron temperature with the delay varying from 0 to 200 ps.

  20. Comments on pulses of characteristic energy produced in solar flare detonations and its possible application to other astrophysical plasmas

    International Nuclear Information System (INIS)

    Kaufmann, P.

    1977-01-01

    A qualitative discussion of physical conditions at neutral sheets was developed in an attempt to explain the repetitive pulsed energy-production mechanism, which has been suggested for solar flares. A characteristic energy per pulse appears to depend critically on the magnetic field strength and dipole length applied to a high temperature plasma, and seem to be regulated by discrete characteristic relative changes in the magnetic moment, following Syrovatskii's model. Discrete energy pulses are produced when neutral sheet thickness approaches to critical values, proportional to the characteristic relative changes in the magnetic moment. Repetition of pulses may occur in multi-sheet configurations as magnetically complex active centres, or at a single sheet where the total system energy change exceeds the critical conditions. The time-scale of the pulsed energy release may be explained by the tearing mode instability, and the repetition time-scale might be understood by the Sweet mechanism in limit conditions. The mechanism might have attractive applications in other high temperature astrophysical plasmas. An empirical relation is derived for pulses' energy prediction, in orders of magnitude, and some possible tests were suggested. An attempt was made to interpret soft γ-ray events of cosmic origin. (Auth.)

  1. Comments on pulses of characteristic energy produced in solar flare detonations and its possible application to other astrophysical plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Kaufmann, P [Universidade Mackenzie, Sao Paulo (Brazil). Centro de Radio-Astronomia e Astrofisica

    1977-06-01

    A qualitative discussion of physical conditions at neutral sheets was developed in an attempt to explain the repetitive pulsed energy-production mechanism, which has been suggested for solar flares. A characteristic energy per pulse appears to depend critically on the magnetic field strength and dipole length applied to a high temperature plasma, and seem to be regulated by discrete characteristic relative changes in the magnetic moment, following Syrovatskii's model. Discrete energy pulses are produced when neutral sheet thickness approaches to critical values, proportional to the characteristic relative changes in the magnetic moment. Repetition of pulses may occur in multi-sheet configurations as magnetically complex active centres, or at a single sheet where the total system energy change exceeds the critical conditions. The time-scale of the pulsed energy release may be explained by the tearing mode instability, and the repetition time-scale might be understood by the Sweet mechanism in limit conditions. The mechanism might have attractive applications in other high temperature astrophysical plasmas. An empirical relation is derived for pulses' energy prediction, in orders of magnitude, and some possible tests were suggested. An attempt was made to interpret soft ..gamma..-ray events of cosmic origin.

  2. 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)

  3. Control of the Effective Free-Energy Landscape in a Frustrated Magnet by a Field Pulse

    Science.gov (United States)

    Wan, Yuan; Moessner, Roderich

    2017-10-01

    Thermal fluctuations can lift the degeneracy of a ground state manifold, producing a free-energy landscape without accidentally degenerate minima. In a process known as order by disorder, a subset of states incorporating symmetry breaking may be selected. Here, we show that such a free-energy landscape can be controlled in a nonequilibrium setting as the slow motion within the ground state manifold is governed by the fast modes out of it. For the paradigmatic case of the classical pyrochlore X Y antiferromagnet, we show that a uniform magnetic field pulse can excite these fast modes to generate a tunable effective free-energy landscape with minima at thermodynamically unstable portions of the ground state manifold.

  4. Energy-separated sequential irradiation for ripple pattern tailoring on silicon surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Tanuj [Department of Physics, Central University of Haryana, Jant-Pali, Mahendergarh 1123029 (India); Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067 (India); Kumar, Manish, E-mail: manishbharadwaj@gmail.com [Department of Physics, Central University of Rajasthan, Kishangarh 305801 (India); Panchal, Vandana [Department of Physics, National Institute of Technology, Kurukshetra 136119 (India); Sahoo, P.K. [School of Physical Sciences, National Institute of Science Education and Research, Bhubaneswar 751005 (India); Kanjilal, D. [Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067 (India)

    2015-12-01

    Highlights: • A new process for controlling the near-surface amorphization of ripples on Si surfaces. • Ripples generation by 100 KeV Ar{sup +} and amorphization control by 60 KeV Ar{sup +} irradiation. • Advantage of energy-separated irradiation demonstrated by detailed RBS and AFM studies. • Relevant mechanism is presented on the basis of DAMAGE and SIMNRA simulations. • Key role of solid flow towards the amorphous/crystalline interface is demonstrated. - Abstract: Nanoscale ripples on semiconductor surfaces have potential application in biosensing and optoelectronics, but suffer from uncontrolled surface-amorphization when prepared by conventional ion-irradiation methods. A two-step, energy-separated sequential-irradiation enables simultaneous control of surface-amorphization and ripple-dimensions on Si(1 0 0). The evolution of ripples using 100 keV Ar{sup +} bombardment and further tuning of the patterns using a sequential-irradiation by 60 keV Ar{sup +} at different fluences are demonstrated. The advantage of this approach as opposed to increased fluence at the same energy is clarified by atomic force microscopy and Rutherford backscattering spectroscopy investigations. The explanation of our findings is presented through DAMAGE simulation.

  5. Development of an intermediate energy heavy-ion micro-beam irradiation system

    International Nuclear Information System (INIS)

    Song Mingtao; Wang Zhiguang; He Yuan; Gao Daqing; Yang Xiaotian; Liu Jie; Su Hong; Man Kaidi; Sheng Li'na

    2008-01-01

    The micro-beam irradiation system, which focuses the beam down the micron order and precisely delivers a predefined number of ions to a predefined spot of micron order, is a powerful tool for radio-biology, radio-biomedicine and micromachining. The Institute of Modern Physics of Chinese Academy of Sciences is developing a heavy-ion micro-beam irradiation system up to intermediate energy. Based on the intermediate and low energy beam provided by Heavy Ion Research Facility of Lanzhou, the micro-beam system takes the form of the magnetic focusing. The heavy-ion beam is conducted to the basement by a symmetrical achromatic system consisting of two vertical bending magnets and a quadrupole in between. Then a beam spot of micron order is formed by magnetic triplet quadrupole of very high gradient. The sample can be irradiated either in vacuum or in the air. This system will be the first opening platform capable of providing heavy ion micro-beam, ranging from low (10 MeV/u) to intermediate energy (100 MeV/u), for irradiation experiment with positioning and counting accuracy. Target material may be biology cell, tissue or other non-biological materials. It will be a help for unveiling the essence of heavy-ion interaction with matter and also a new means for exploring the application of heavy-ion irradiation. (authors)

  6. Effects of high-intensity pulse irradiation with linear polarized near-infrared rays and stretching on muscle tone in patients with cerebrovascular disease: a randomized controlled trial.

    Science.gov (United States)

    Takeuchi, Nobuyuki; Takezako, Nobuhiro; Shimonishi, Yuko; Usuda, Shigeru

    2017-08-01

    [Purpose] The purpose of this study was to clarify the influence of high-intensity pulse irradiation with linear polarized near-infrared rays (HI-LPNR) and stretching on hypertonia in cerebrovascular disease patients. [Subjects and Methods] The subjects were 40 cerebrovascular disease patients with hypertonia of the ankle joint plantar flexor muscle. The subjects were randomly allocated to groups undergoing treatment with HI-LPNR irradiation (HI-LPNR group), stretching (stretching group), HI-LPNR irradiation followed by stretching (combination group), and control group (10 subjects each). In all groups, the passive range of motion of ankle dorsiflexion and passive resistive joint torque of ankle dorsiflexion were measured before and after the specified intervention. [Results] The changes in passive range of motion, significant increase in the stretching and combination groups compared with that in the control group. The changes in passive resistive joint torque, significant decrease in HI-LPNR, stretching, and combination groups compared with that in the control group. [Conclusion] HI-LPNR irradiation and stretching has effect of decrease muscle tone. However, combination of HI-LPNR irradiation and stretching has no multiplier effect.

  7. Full 3D modelling of pulse propagation enables efficient nonlinear frequency conversion with low energy laser pulses in a single-element tripler

    Science.gov (United States)

    Kardaś, Tomasz M.; Nejbauer, Michał; Wnuk, Paweł; Resan, Bojan; Radzewicz, Czesław; Wasylczyk, Piotr

    2017-02-01

    Although new optical materials continue to open up access to more and more wavelength bands where femtosecond laser pulses can be generated, light frequency conversion techniques are still indispensable in filling the gaps on the ultrafast spectral scale. With high repetition rate, low pulse energy laser sources (oscillators) tight focusing is necessary for a robust wave mixing and the efficiency of broadband nonlinear conversion is limited by diffraction as well as spatial and temporal walk-off. Here we demonstrate a miniature third harmonic generator (tripler) with conversion efficiency exceeding 30%, producing 246 fs UV pulses via cascaded second order processes within a single laser beam focus. Designing this highly efficient and ultra compact frequency converter was made possible by full 3-dimentional modelling of propagation of tightly focused, broadband light fields in nonlinear and birefringent media.

  8. Applications of pulsed energy sources and hydrodynamic response to materials science

    International Nuclear Information System (INIS)

    Perry, F.; Nelson, W.

    1993-01-01

    The dynamic response of materials to pulsed, relativistic electron beams was studied for materials science applications over two decades ago. Presently, intense light ion beams are being explored for materials science applications. These include the Ion Beam Surface Treatment (IBEST) of materials for producing stronger and more corrosion-resistant materials and the evaporative deposition of polycrystalline thin films. Laser sources are also being extensively utilized as pulsed energy sources in medical science and in clinical applications. In particular, laser-tissue interactions are being investigated for laser angioplasty and surgery as well as cancer therapy. The understanding of the energy deposition and hydrodynamic response of a wide range of materials is essential to the success of these applications. In order to address these materials science applications, the authors are utilizing and developing high quality, energy deposition-hydrodynamic code techniques which can aid in the design and interpretation of experiments. Consequently, the authors strongly encourage the development of 3-dimensional, species-selective diagnostic techniques, e.g. Resonant Holographic Interferometry Spectroscopy (RHIS), to be used in analyzing the ablation plume in the thin film deposition experiments. In this presentation they show the results and discuss the limitations of calculations for these materials applications. They also discuss the status of the RHIS diagnostic

  9. Improved fission neutron energy discrimination with {sup 4}He detectors through pulse filtering

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Ting, E-mail: ting.zhu@ufl.edu [University of Florida, Gainesville, FL (United States); Liang, Yinong; Rolison, Lucas; Barker, Cathleen; Lewis, Jason; Gokhale, Sasmit [University of Florida, Gainesville, FL (United States); Chandra, Rico [Arktis Radiation Detectors Ltd., Räffelstrasse 11, Zürich (Switzerland); Kiff, Scott [Sandia National Laboratories, CA (United States); Chung, Heejun [Korean Institute for Nuclear Nonproliferation and Control, 1534 Yuseong-daero, Yuseong-gu, Daejeon (Korea, Republic of); Ray, Heather; Baciak, James E.; Enqvist, Andreas; Jordan, Kelly A. [University of Florida, Gainesville, FL (United States)

    2017-03-11

    This paper presents experimental and computational techniques implemented for {sup 4}He gas scintillation detectors for induced fission neutron detection. Fission neutrons are produced when natural uranium samples are actively interrogated by 2.45 MeV deuterium-deuterium fusion reaction neutrons. Fission neutrons of energies greater than 2.45 MeV can be distinguished by their different scintillation pulse height spectra since {sup 4}He detectors retain incident fast neutron energy information. To enable the preferential detection of fast neutrons up to 10 MeV and suppress low-energy event counts, the detector photomultiplier gain is lowered and trigger threshold is increased. Pile-up and other unreliable events due to the interrogating neutron flux and background radiation are filtered out prior to the evaluation of pulse height spectra. With these problem-specific calibrations and data processing, the {sup 4}He detector's accuracy at discriminating fission neutrons up to 10 MeV is improved and verified with {sup 252}Cf spontaneous fission neutrons. Given the {sup 4}He detector's ability to differentiate fast neutron sources, this proof-of-concept active-interrogation measurement demonstrates the potential of special nuclear materials detection using a {sup 4}He fast neutron detection system.

  10. Pulse-height response of silicon surface-barrier detectors to high-energy heavy ions

    International Nuclear Information System (INIS)

    Smith, G.D.

    1973-01-01

    The pulse-height defect (PHD) of high-energy heavy ions in silicon surface-barrier detectors can be divided into three components: (1) energy loss in the gold-surface layer, (2) a nuclear-stopping defect, and (3) a defect due to recombination of electron-hole pairs in the plasma created by the heavy ion. The plasma recombination portion of the PHD was the subject of this study using the variation of the PHD with (1) the angle of incidence of incoming heavy ions, and (2) changes in the detector bias. The Tandem Van de Graaff accelerator at Argonne National Laboratory was used to produce scattered beam ions ( 32 S, 35 Cl) and heavy target recoils (Ni, Cu, 98 Mo, Ag, Au) at sufficient energies to produce a significant recombination defect. The results confirm the existence of a recombination zone at the front surface of these detectors and the significance of plasma recombination as a portion of the pulse-height defect. (Diss. Abstr. Int., B)

  11. Interaction of single-pulse laser energy with bow shock in hypersonic flow

    Directory of Open Access Journals (Sweden)

    Hong Yanji

    2014-04-01

    Full Text Available Pressure sensing and schlieren imaging with high resolution and sensitivity are applied to the study of the interaction of single-pulse laser energy with bow shock at Mach 5. An Nd:YAG laser operated at 1.06 μm, 100 mJ pulse energy is used to break down the hypersonic flow in a shock tunnel. Three-dimensional Navier–Stokes equations are solved with an upwind scheme to simulate the interaction. The pressure at the stagnation point on the blunt body is measured and calculated to examine the pressure variation during the interaction. Schlieren imaging is used in conjunction with the calculated density gradients to examine the process of the interaction. The results show that the experimental pressure at the stagnation point on the blunt body and schlieren imaging fit well with the simulation. The pressure at the stagnation point on the blunt body will increase when the transmission shock approaches the blunt body and decrease with the formation of the rarefied wave. Bow shock is deformed during the interaction. Quasi-stationary waves are formed by high rate laser energy deposition to control the bow shock. The pressure and temperature at the stagnation point on the blunt body and the wave drag are reduced to 50%, 75% and 81% respectively according to the simulation. Schlieren imaging has provided important information for the investigation of the mechanism of the interaction.

  12. Pulse Power Capability Of High Energy Density Capacitors Based on a New Dielectric Material

    Science.gov (United States)

    Winsor, Paul; Scholz, Tim; Hudis, Martin; Slenes, Kirk M.

    1999-01-01

    A new dielectric composite consisting of a polymer coated onto a high-density metallized Kraft has been developed for application in high energy density pulse power capacitors. The polymer coating is custom formulated for high dielectric constant and strength with minimum dielectric losses. The composite can be wound and processed using conventional wound film capacitor manufacturing equipment. This new system has the potential to achieve 2 to 3 J/cu cm whole capacitor energy density at voltage levels above 3.0 kV, and can maintain its mechanical properties to temperatures above 150 C. The technical and manufacturing development of the composite material and fabrication into capacitors are summarized in this paper. Energy discharge testing, including capacitance and charge-discharge efficiency at normal and elevated temperatures, as well as DC life testing were performed on capacitors manufactured using this material. TPL (Albuquerque, NM) has developed the material and Aerovox (New Bedford, MA) has used the material to build and test actual capacitors. The results of the testing will focus on pulse power applications specifically those found in electro-magnetic armor and guns, high power microwave sources and defibrillators.

  13. Influence of wave-front curvature on supercontinuum energy during filamentation of femtosecond laser pulses in water

    Science.gov (United States)

    Potemkin, F. V.; Mareev, E. I.; Smetanina, E. O.

    2018-03-01

    We demonstrate that using spatially divergent incident femtosecond 1240-nm laser pulses in water leads to an efficient supercontinuum generation in filaments. Optimal conditions were found when the focal plane is placed 100 -400 μ m before the water surface. Under sufficiently weak focusing conditions [numerical aperture (NA )laser pulses, the supercontinuum energy generated in divergent beams is higher than the supercontinuum energy generated in convergent beams. Analysis by means of the unidirectional pulse propagation equation shows a dramatic difference between filamentation scenarios of divergent and convergent beams, that explains corresponding features of the supercontinuum generation. Under strong focusing conditions (NA ⩾0.2 ) and high-energy laser pulses, the supercontinuum generation is suppressed for convergent beams in contrast to divergent beams that nevertheless are shown experimentally to allow supercontinuum generation. The presented technique of the supercontinuum generation in divergent beams in water is highly demanded in a development of femtosecond optical parametric amplifiers.

  14. Collective Focusing of Intense Ion Beam Pulses for High-energy Density Physics Applications

    International Nuclear Information System (INIS)

    Dorf, Mikhail A.; Kaganovich, Igor D.; Startsev, Edward A.; Davidson, Ronald C.

    2011-01-01

    The collective focusing concept in which a weak magnetic lens provides strong focusing of an intense ion beam pulse carrying a neutralizing electron background is investigated by making use of advanced particle-in-cell simulations and reduced analytical models. The original analysis by Robertson Phys. Rev. Lett. 48, 149 (1982) is extended to the parameter regimes of particular importance for several high-energy density physics applications. The present paper investigates (1) the effects of non-neutral collective focusing in a moderately strong magnetic field; (2) the diamagnetic effects leading to suppression of the applied magnetic field due to the presence of the beam pulse; and (3) the influence of a finite-radius conducting wall surrounding the beam cross-section on beam neutralization. In addition, it is demonstrated that the use of the collective focusing lens can significantly simplify the technical realization of the final focusing of ion beam pulses in the Neutralized Drift Compression Experiment-I (NDCX-I), and the conceptual designs of possible experiments on NDCX-I are investigated by making use of advanced numerical simulations.

  15. Reliability of high-voltage pulse capacitors operating in large energy storages

    International Nuclear Information System (INIS)

    Kuchinskij, G.S.; Fedorova, V.S.; Shilin, O.V.

    1982-01-01

    To improve the reliability of pulse capacitors operating in capacitive energy storages, processes, resulting in break-down of capacitor insulation were investigated. A statistic model of failures was constructed and reliability of real capacitors, functioning at operating electric intensity Usub(oper) equal 70 kV/mm and at elevated intensity 90 kV/mm was calculated. Results of testing the IK50-ZU4 capacitor are given. The form of the capacitor service life distribution function was specified. To provide and confirm the assigned capacitor reliability, it is necessary to speed up tests at a higher voltage (1.3-1.5) Usub(oper). To improve the capacitor reliability, it is advisable to conduct acceptance tests, which include hold at increased constant voltage (1.3-1.5) Usub(oper) during 1-3 min and the effect of pulses of increased voltage (1.2-1.3) Usub(oper) with the pulse shape corresponding to operating conditions

  16. Changes in the surface electronic states of semiconductor fine particles induced by high energy ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Yamaki, Tetsuya; Asai, Keisuke; Ishigure, Kenkichi [Tokyo Univ. (Japan); Shibata, Hiromi

    1997-03-01

    The changes in the surface electronic states of Q-sized semiconductor particles in Langmuir-Blodgett (LB) films, induced by high energy ion irradiation, were examined by observation of ion induced emission and photoluminescence (PL). Various emission bands attributed to different defect sites in the band gap were observed at the initial irradiation stage. As the dose increased, the emissions via the trapping sites decreased in intensity while the band-edge emission developed. This suggests that the ion irradiation would remove almost all the trapping sites in the band gap. The low energy emissions, which show a multiexponential decay, were due to a donor-acceptor recombination between the deeply trapped carriers. It was found that the processes of formation, reaction, and stabilization of the trapping sites would predominantly occur under the photooxidizing conditions. (author)

  17. In vitro digestible energy of some agricultural residues, as influenced by gamma irradiation and sodium hydroxide

    International Nuclear Information System (INIS)

    Al-Masri, M.R.

    1999-01-01

    Experiments have been carried out to study the changes in the values of in vitro apparent organic matter digestibility (IVOMD) and in vitro digestible energy (IVDE) of wheat straw (WS), cotton seed shell (CSS), peanut shell (PS), soybean shell (SS), extracted olive cake (EOC) and extracted unpeeled sunflower seeds (ESS) after irradiation by various doses of gamma radiation (0, 100, 150, 200 kGy) or after spraying with different amounts of sodium hydroxide (NaOH): 0, 2, 4, and 6 g NaOH/25 ml water/100 g DM. The results indicate that there were significant increases in IVOMD and IVDE values for all irradiated samples and for sodium hydroxide treatments except for SS and ESS. Combined treatment of irradiation and sodium hydroxide resulted in a larger increase in the digestible energy than the individual treatments

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

    International Nuclear Information System (INIS)

    Gardner, J.W.

    1980-01-01

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

  19. Irradiation of amorphous Ta{sub 42}Si{sub 13}N{sub 45} film with a femtosecond laser pulse

    Energy Technology Data Exchange (ETDEWEB)

    Romano, V. [University of Bern, Institute of Applied Physics, Bern (Switzerland); Bern University of Applied Sciences, Bern (Switzerland); Meier, M. [University of Bern, Institute of Applied Physics, Bern (Switzerland); Theodore, N.D. [Freescale Semiconductor Inc., Tempe, AZ (United States); Marble, D.K. [Tarleton State University, Stephenville, TX (United States); Nicolet, M.A. [California Institute of Technology, Pasadena, CA (United States)

    2011-07-15

    Films of 260 nm thickness, with atomic composition Ta{sub 42}Si{sub 13}N{sub 45}, on 4'' silicon wafers, have been irradiated in air with single laser pulses of 200 femtoseconds duration and 800 nm wave length. As sputter-deposited, the films are structurally amorphous. A laterally truncated Gaussian beam with a near-uniform fluence of {proportional_to}0.6 J/cm{sup 2} incident normally on such a film ablates 23 nm of the film. Cross-sectional transmission electron micrographs show that the surface of the remaining film is smooth and flat on a long-range scale, but contains densely distributed sharp nanoprotrusions that sometimes surpass the height of the original surface. Dark field micrographs of the remaining material show no nanograins. Neither does glancing angle X-ray diffraction with a beam illuminating many diffraction spots. By all evidence, the remaining film remains amorphous after the pulsed femtosecond irradiation. The same single pulse, but with an enhanced and slightly peaked fluence profile, creates a spot with flat peripheral terraces whose lateral extents shrink with depth, as scanning electron and atomic force micrographs revealed. Comparison of the various figures suggests that the sharp nanoprotrusions result from an ejection of material by brittle fraction and spallation, not from ablation by direct beam-solid interaction. Conditions under which spallation should dominate over ablation are discussed. (orig.)

  20. Retrospective Study on Laser Treatment of Oral Vascular Lesions Using the "Leopard Technique": The Multiple Spot Irradiation Technique with a Single-Pulsed Wave.

    Science.gov (United States)

    Miyazaki, Hidetaka; Ohshiro, Takafumi; Romeo, Umberto; Noguchi, Tadahide; Maruoka, Yutaka; Gaimari, Gianfranco; Tomov, Georgi; Wada, Yoshitaka; Tanaka, Kae; Ohshiro, Toshio; Asamura, Shinichi

    2018-06-01

    This study aimed to retrospectively evaluate the efficacy and safety of laser treatment of oral vascular lesions using the multiple spot irradiation technique with a single-pulsed wave. In laser therapy for vascular lesions, heat accumulation induced by excessive irradiation can cause adverse events postoperatively, including ulcer formation, resultant scarring, and severe pain. To prevent heat accumulation and side effects, we have applied a multiple pulsed spot irradiation technique, the so-called "leopard technique" (LT) to oral vascular lesions. This approach was originally proposed for laser treatment of nevi. It can avoid thermal concentration at the same spot and spare the epithelium, which promotes smooth healing. The goal of the study was to evaluate this procedure and treatment outcomes. The subjects were 46 patients with 47 oral vascular lesions treated with the LT using a Nd:YAG laser (1064 nm), including 24 thick lesions treated using a combination of the LT and intralesional photocoagulation. All treatment outcomes were satisfactory without serious complications such as deep ulcer formation, scarring, bleeding, or severe swelling. Laser therapy with the LT is a promising less-invasive treatment for oral vascular lesions.

  1. Sub-micron magnetic patterns and local variations of adhesion force induced in non-ferromagnetic amorphous steel by femtosecond pulsed laser irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Huiyan; Feng, Yuping [Departament de Física, Universitat Autònoma de Barcelona, Bellaterra, E08193 (Spain); Nieto, Daniel [Microoptics and GRIN Optics Group, Applied Physics Department, University of Santiago de Compostela, E15782 Santiago de Compostela (Spain); García-Lecina, Eva [Unidad de Superficies Metálicas, IK4-CIDETEC, E20009 Donostia-San Sebastián Gipuzkoa (Spain); Mcdaniel, Clare [National Centre for Laser Applications, School of Physics, National University of Ireland, Galway (Ireland); Díaz-Marcos, Jordi [Unitat de Tècniques Nanomètriques, Centres Científics i Tecnològics, Universitat de Barcelona, E08028 Barcelona (Spain); Flores-Arias, María Teresa [Microoptics and GRIN Optics Group, Applied Physics Department, University of Santiago de Compostela, E15782 Santiago de Compostela (Spain); O’Connor, Gerard M. [National Centre for Laser Applications, School of Physics, National University of Ireland, Galway (Ireland); Baró, Maria Dolors [Departament de Física, Universitat Autònoma de Barcelona, Bellaterra, E08193 (Spain); Pellicer, Eva, E-mail: eva.pellicer@uab.cat [Departament de Física, Universitat Autònoma de Barcelona, Bellaterra, E08193 (Spain); and others

    2016-05-15

    Highlights: • Formation of ripples after femtosecond pulsed laser irradiation (FSPLI) of metallic glass was studied. • Magnetic patterning at the surface of non-ferromagnetic amorphous steel was induced by FSPLI. • The origin of the generated ferromagnetism is the laser-induced devitrification. - Abstract: Periodic ripple and nanoripple patterns are formed at the surface of amorphous steel after femtosecond pulsed laser irradiation (FSPLI). Formation of such ripples is accompanied with the emergence of a surface ferromagnetic behavior which is not initially present in the non-irradiated amorphous steel. The occurrence of ferromagnetic properties is associated with the laser-induced devitrification of the glassy structure to form ferromagnetic (α-Fe and Fe{sub 3}C) and ferrimagnetic [(Fe,Mn){sub 3}O{sub 4} and Fe{sub 2}CrO{sub 4}] phases located in the ripples. The generation of magnetic structures by FSPLI turns out to be one of the fastest ways to induce magnetic patterning without the need of any shadow mask. Furthermore, local variations of the adhesion force, wettability and nanomechanical properties are also observed and compared to those of the as-cast amorphous alloy. These effects are of interest for applications (e.g., biological, magnetic recording, etc.) where both ferromagnetism and tribological/adhesion properties act synergistically to optimize material performance.

  2. Effects of H-implantation energy on the optical stability of implanted usher films under photo-irradiation

    International Nuclear Information System (INIS)

    Awazu, K.; Yasui, H.; Kasamori, M.; Ichikawa, T.; Funada, Y.; Iwaki, M.

    1999-01-01

    A study has been made on the improvement of the optical stability of urushi films under optical irradiation using ion implantation. Ion implantation of hydrogen ions in urushi films was performed with a dose of 10 15 ions/cm 2 at ion energies ranging from 0.2 to 150 keV at room temperature. The photo-irradiation onto the urushi films was carried out at irradiation energies ranging from 40 to 400 MJ/m 2 . H-implantation onto urushi films is useful for improving the optical stability under photo-irradiation when the implantation energy is larger than 60 keV

  3. Spatial correlation of energy deposition events in irradiated liquid water

    International Nuclear Information System (INIS)

    Hamm, R.N.; Wright, H.A.; Turner, J.E.; Ritchie, R.H.

    1978-01-01

    Monte Carlo electron transport computer code is used to study in detail the slowing down of electrons and all of their secondaries with initial energies up to 1.5 MeV in liquid water. The probability distributions for the number of ionizations and for the energy deposited in cubical volume elements from electron tracks in the water are analyzed. Both the electron energies and the sizes of the cubical cells are varied. Results are shown for electron energies between 100 eV and 10 keV and for cell sizes between 40 A and 1500 A. Good general agreement is found with results presented by Paretzke at the last symposium. The code can be used to obtain other basic distributions of importance in microdosimetry. As an example, microdosimetric single-event spectra for 500-eV electrons are computed in cubes with edges that range in size from 40 A to 200 A. The importance of correlations is shown explicitly in a comparison of secondary electrons produced by 60 Co and 50-keV photons

  4. Chemical and physical analysis on hard tissues after irradiation with short pulse Nd:YAG laser; Alteracoes quimicas e fisicas de tecidos duros irradiados por laser de neodimio chaveado

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Andrea Antunes

    2003-07-01

    This work reports on a study that was designed to investigate chemical, physical and morphological alterations in the dental enamel surface. The influence of application of laser in enamel surface by microscopic technical, X-ray fluorescence for chemical analysis, physical property as well as hardness and thermal analysis with Nd:YAG laser is also pointed out. A prototype of Nd:YAG (Q-switched) laser developed at the Center of Lasers and Applications - Institute of Energetic and Nuclear Research, aiming applications in the Medical Sciences that typical wavelength of 1.064 nm was used. The modifications in human dental enamel chemical composition for major and trace elements are here outlined. The accuracy of procedures was performed by analysis of natural hydroxyapatite as standard reference material. The identification and quantification of the chemical elements presented in the dental tissue samples were performed trough EDS, XRF and INAA. We determined the rate Calcium/Phosphorus (Ca/P) for different techniques. We performed an analysis in different regions of the surface and for different areas allowing a description of the chemical change in the total area of the specimen and the assessment of the compositional homogeneity of the each specimen. A comparison between XRF and INAA is presented. Based on morphological analysis of the irradiated surfaces with short pulse Nd:YAG laser we determined the area surrounded by the irradiation for the parameters for this thesis, and this technique allowed us to visualize the regions of fusion and re-solidification. The energy densities ranged from 10 J/cm{sup 2} to 40 J/cm{sup 2}, with pulse width of 6, 10 e 200 ns, and repetition rates of 5 and 7 Hz. In this thesis, FTIR-spectroscopy is used to analyze powder of mineralized tissue as well as enamel, dentine, root and cementum for human and bovine teeth after irradiation with short-pulse Nd:YAG laser. Characteristic spectra were obtained for the proteins components and

  5. Energy-producing system of the membrane potential generation in γ-irradiated Streptococcus faecalis

    International Nuclear Information System (INIS)

    Fomenko, B.S.

    1976-01-01

    γ-irradiated (20-100 krads) Str. faecalis cells exhibited increased glycolytic and ATPase activity whereas the ATP level remained unaffected by radiation. It is concluded that the radiation-induced reduction of the membrane potential in Str. faecalis, that has been earlier described, is not connected with the impairment of the energy-producing system of the potential generation

  6. Fractal characteristics of fracture morphology of steels irradiated with high-energy ions

    Energy Technology Data Exchange (ETDEWEB)

    Xian, Yongqiang; Liu, Juan [Institute of Modern Physics, Chinese Academy of Science, Lanzhou 730000 (China); University of Chinese Academy of Science, Beijing 100049 (China); Zhang, Chonghong, E-mail: c.h.zhang@impcas.ac.cn [Institute of Modern Physics, Chinese Academy of Science, Lanzhou 730000 (China); Chen, Jiachao [Paul Scherrer Institute, Villigen PSI (Switzerland); Yang, Yitao; Zhang, Liqing; Song, Yin [Institute of Modern Physics, Chinese Academy of Science, Lanzhou 730000 (China)

    2015-06-15

    Highlights: • Fractal dimensions of fracture surfaces of steels before and after irradiation were calculated. • Fractal dimension can effectively describe change of fracture surfaces induced by irradiation. • Correlation of change of fractal dimension with embrittlement of irradiated steels is discussed. - Abstract: A fractal analysis of fracture surfaces of steels (a ferritic/martensitic steel and an oxide-dispersion-strengthened ferritic steel) before and after the irradiation with high-energy ions is presented. Fracture surfaces were acquired from a tensile test and a small-ball punch test (SP). Digital images of the fracture surfaces obtained from scanning electron microscopy (SEM) were used to calculate the fractal dimension (FD) by using the pixel covering method. Boundary of binary image and fractal dimension were determined with a MATLAB program. The results indicate that fractal dimension can be an effective parameter to describe the characteristics of fracture surfaces before and after irradiation. The rougher the fracture surface, the larger the fractal dimension. Correlation of the change of fractal dimension with the embrittlement of the irradiated steels is discussed.

  7. A permanent magnet electron beam spread system used for a low energy electron irradiation accelerator

    International Nuclear Information System (INIS)

    Huang Jiang; Xiong Yongqian; Chen Dezhi; Liu Kaifeng; Yang Jun; Li Dong; Yu Tiaoqin; Fan Mingwu; Yang Bo

    2014-01-01

    The development of irradiation processing industry brings about various types of irradiation objects and expands the irradiation requirements for better uniformity and larger areas. This paper proposes an innovative design of a permanent magnet electron beam spread system. By clarifying its operation principles, the author verifies the feasibility of its application in irradiation accelerators for industrial use with the examples of its application in electron accelerators with energy ranging from 300 keV to 1 MeV. Based on the finite element analyses of electromagnetic fields and the charged particle dynamics, the author also conducts a simulation of electron dynamics in magnetic field on a computer. The results indicate that compared with the traditional electron beam scanning system, this system boosts the advantages of a larger spread area, non-power supply, simple structure and low cost, etc., which means it is not only suitable for the irradiation of objects with the shape of tubes, strips and panels, but can also achieve a desirable irradiation performance on irregular constructed objects of large size. (authors)

  8. Time-dose relationship of erythema in high energy photon irradiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Hidetoshi (Gifu Prefectural Tajimi Hospital (Japan)); Sakuma, Sadayuki

    1992-01-01

    Skin doses of 100 patients who were treated with high energy ionizing irradiation during conventional irradiation therapy were measured by thermoluminescence dosimeter (TLD). In 87 of the 100 patients, acute hyperemic change of the skin (erythema) of the irradiated region was observed. In the other 13 patients, alopetia of the scalp was observed. The following conclusions were reached. The time-dose relationship was linear when erythema tolerance was used as an index, but not when alopecia was used. The tolerance dose for erythema was lower than previously reported. The slope of the isoeffect curve on the log-log plot of total absorbed skin dose against total number of days after the first irradiation was 0.68 when erythema was used as an index. This number is larger than previously reported results. We considered that erythema is significantly influenced by fraction size and that hyperfractionation is a promising method of irradiation, especially in Japan. Combined use of chemotherapeutic agents, such as 5-FU, accelerated erythema. The slope of combined treatment was 0.86. Observing acute hyperemic change of skin is considered to be a useful method of investigating the combined effects of chemotherapeutic agents on irradiation. (author).

  9. Physics and applications of high energy density plasmas. Extreme state driven by pulsed electromagnetic energy

    International Nuclear Information System (INIS)

    Horioka, Kazuhiko

    2002-06-01

    The papers presented at the symposium on ''Physics and application of high energy density plasmas, held December 20-21, 2001 at NIFS'' are collected in this proceedings. The topics covered in the meeting include dense z-pinches, plasma focus, intense charged particle beams, intense radiation sources, discharge pumped X-ray lasers, their diagnostics, and applications of them. The papers reflect the present status and trends in the research field of high energy density plasmas. (author)

  10. Highly efficient actively Q-switched Yb:LGGG laser generating 3.26 mJ of pulse energy

    Science.gov (United States)

    Li, Yanbin; Zhang, Jian; Zhao, Ruwei; Zhang, Baitao; He, Jingliang; Jia, Zhitai; Tao, Xutang

    2018-05-01

    An efficient acousto-optic Q-switched laser operation of Yb:(LuxGd1-x)3Ga5O12 (x = 0.062) (Yb:LGGG) crystal is demonstrated, producing stable pulses with repetition rate ranging from 1 to 20 kHz. Under the absorbed pump power of 8.75 W, the maximum average output power of 3.26 W is obtained at the pulse repletion rate of 1 kHz, corresponding to the slope efficiency as high as 52%. The pulse width of 14.5 ns is achieved with the pulse energy and peak power of 3.26 mJ and 225 kW, respectively. It indicates great potential of Yb:LGGG crystal for generating pulsed lasers.

  11. The U.S. Department of Energy Program in low-dose food irradiation

    International Nuclear Information System (INIS)

    Krenz, D.L.; McMullen, W.H.

    1985-01-01

    The U.S. Department of Energy's Byproducts Utilization Program (BUP) seeks to develop and encourage the widespread beneficial commercial use of waste byproducts produced by Department of Energy (DOE) programs. These byproducts are generally radioactive to varying degrees and consist of fission products resulting from irradiation of nuclear reactor fuel for production of special nuclear material at DOE facilities in Richland, Washington, and Savannah River, South Carolina

  12. Ultrastructural analysis of root canal dentine irradiated with 980-nm diode laser energy at different parameters.

    Science.gov (United States)

    Marchesan, Melissa Andréia; Brugnera-Junior, Aldo; Souza-Gabriel, Aline Evangelista; Correa-Silva, Silvio Rocha; Sousa-Neto, Manoel D

    2008-06-01

    The purpose of this in vitro study was to investigate using the scanning electron microscope (SEM) the ultrastructural morphological changes of the radicular dentine surface after irradiation with 980-nm diode laser energy at different parameters and angles of incidence. There have been limited reports on the effects of diode laser irradiation at 980 nm on radicular dentin morphology. Seventy-two maxillary canines were sectioned and roots were biomechanically prepared using K3 rotary instruments. The teeth were irrigated with 2 mL of distilled water between files and final irrigation was performed with 10 mL of distilled water. The teeth were then randomly divided into five groups (n = 8 each) according to their diode laser parameters: Group 1: no irradiation (control); group 2: 1.5 W/continuous wave (CW) emission (the manufacturer's parameters); group 3: 1.5 W/100 Hz; group 4: 3 W/CW; and group 5: 3 W/100 Hz. Laser energy was applied with helicoid movements (parallel to the canal walls) for 20 sec. Eight additional teeth for each group were endodontically prepared and split longitudinally and irradiation was applied perpendicularly to the root surface. Statistical analysis showed no difference between the root canal thirds irradiated with the 980-nm diode laser, and similar results between the parameters 1.5 W/CW and 3 W/100 Hz (p > 0.05). When considering different output powers and delivery modes our results showed that changes varied from smear layer removal to dentine fusion.

  13. Free radical production by high energy shock waves--comparison with ionizing irradiation.

    Science.gov (United States)

    Morgan, T R; Laudone, V P; Heston, W D; Zeitz, L; Fair, W R

    1988-01-01

    Fricke chemical dosimetry is used as an indirect measure of the free radical production of ionizing irradiation. We adapted the Fricke ferrous sulfate radiation dosimeter to examine the chemical effects of high energy shock waves. Significant free radical production was documented. The reaction was dose dependent, predictably increased by acoustic impedance, but curvilinear. A thousand shocks at 18 kilovolts induced the same free radical oxidation as 1100 rad cobalt-60 gamma ionizing irradiation, increasing to 2900 rad in the presence of an air-fluid zone of acoustic impedance. The biological effect of these free radicals was compared to that of cobalt-60 ionizing irradiation by measuring the affect on Chinese hamster cells by clonogenic assay. While cobalt-60 irradiation produced a marked decrease in clonogenic survivors, little effect was noted with high energy shock waves. This suggested that the chemical effects produced by shock waves were either absent or attenuated in the cells, or were inherently less toxic than those of ionizing irradiation.

  14. Photoluminescence and reflectivity studies of high energy light ions irradiated polymethyl methacrylate films

    Science.gov (United States)

    Bharti, Madhu Lata; Singh, Fouran; Ramola, R. C.; Joshi, Veena

    2017-11-01

    The self-standing films of non-conducting polymethyl methacrylate (PMMA) were irradiated in vacuum using high energy light ions (HELIs) of 50 MeV Lithium (Li+3) and 80 MeV Carbon (C+5) at various ion dose to induce the optical changes in the films. Upon HELI irradiation, films exhibit a significant enhancement in optical reflectivity at the highest dose. Interestingly, the photoluminescence (PL) emission band with green light at (514.5 nm) shows a noticeable increase in the intensity with increasing ion dose for both ions. However, the rate of increase in PL intensity is different for both HELI and can be correlated with the linear energy transfer by these ions in the films. Origin of PL is attributed to the formation of carbon cluster and hydrogenated amorphous carbon in the polymer films. HAC clusters act as PL active centres with optical reflectivity. Most of the harmful radiation like UV are absorbed by the material and is becoming opaque after irradiation and this PL active material are useful in fabrication of optoelectronic devices, UV-filter, back-lit components in liquid crystal display systems, micro-components for integrate optical circuits, diffractive elements, advanced materials and are also applicable to the post irradiation laser treatment by means of ion irradiation.

  15. Use of the SPIRAL 2 facility for material irradiations with 14 MeV energy neutrons

    International Nuclear Information System (INIS)

    Mosnier, A.; Ridikas, D.; Ledoux, X.; Pellemoine, F.; Anne, R.; Huguet, Y.; Lipa, M.; Magaud, P.; Marbach, G.; Saint-Laurent, M.G.; Villari, A.C.C.

    2005-01-01

    The primary goal of an irradiation facility for fusion applications will be to generate a material irradiation database for the design, construction, licensing and safe operation of a fusion demonstration power station (e.g., DEMO). This will be achieved through testing and qualifying material performance under neutron irradiation that simulates service up to the full lifetime anticipated in the power plant. Preliminary investigations of 14 MeV neutron effects on different kinds of fusion material could be assessed by the SPIRAL 2 Project at GANIL (Caen, France), aiming at rare isotope beams production for nuclear physics research with first beams expected by 2009. In SPIRAL 2, a deuteron beam of 5 mA and 40 MeV interacts with a rotating carbon disk producing high-energy neutrons (in the range between 1 and 40 MeV) via C (d, xn) reactions. Then, the facility could be used for 3-4 months y -1 for material irradiation purposes. This would correspond to damage rates in the order of 1-2 dpa y -1 (in Fe) in a volume of ∼10 cm 3 . Therefore, the use of miniaturized specimens will be essential in order to effectively utilize the available irradiation volume in SPIRAL 2. Sample package irradiation temperature would be in the range of 250-1000 deg. C. The irradiation level of 1-2 dpa y -1 with 14 MeV neutrons (average energy) may be interesting for micro-structural and metallurgical investigations (e.g., mini-traction, small punch tests, etc.) and possibly for the understanding of specimen size/geometric effects of critical material properties. Due to the small test cell volume, sample in situ experiments are not foreseen. However, sample packages would be, if required, available each month after transfer in a special hot cell on-site

  16. Simulation calculation for the energy deposition profile and the transmission fraction of intense pulsed electron beam at various incident angles

    International Nuclear Information System (INIS)

    Yang Hailiang; Qiu Aici; Zhang Jiasheng; Huang Jianjun; Sun Jianfeng

    2002-01-01

    The incident angles have a heavy effect on the intense pulsed electron beam energy deposition profile, energy deposition fraction and beam current transmission fraction in material. The author presents electron beam energy deposition profile and energy deposition fraction versus electron energy (0.5-2.0 MeV), at various incident angles for three aluminum targets of various thickness via theoretical calculation. The intense pulsed electron beam current transmission fractions versus electron energy (0.4-1.4 MeV) at various incident angles for three thickness of carbon targets were also theoretically calculated. The calculation results indicate that the deposition energy in unit mass of material surface layer increase with the rise of electron beam incident angle, and electron beam with low incident angle (closer to normal incident angle) penetrates deeper into the target material. The electron beams deposit more energy in unit mass of material surface layer at 60 degree-70 degree incident angle

  17. Relaxation and excitation electronic processes in dielectrics irradiated by ultrafast IR and VUV pulses; Processus electroniques d'excitation et de relaxation dans les solides dielectriques excites par des impulsions IR et XUV ultracourtes

    Energy Technology Data Exchange (ETDEWEB)

    Gaudin, J

    2005-11-15

    We studied excitation and relaxation of electrons involved during interaction of visible and VUV femtosecond pulses with dielectrics. The generated population of hot electrons, having energy of few eV to few tens of eV above the bottom of the conduction band, is responsible of phenomena ranging to defect creation to optical breakdown. Owing to two techniques: photoemission and transient photoconductivity we improve the understanding of the The first photoemission experiments deal with dielectrics irradiated by 30 fs IR pulses. The photoemission spectra measured show a large population of electrons which energy rise up to 40 eV. We interpret this result in terms of a new absorption process: direct multi-photons inter-branch transitions. The 2. type of photoemission experiments are time resolved 'pump/probe' investigation. We study the relaxation of electrons excited by a VUV pulses. We used the high order harmonics (HOH) as light sources. We found surprisingly long decay time in the range of ps timescale. Last type of experiments is photoconductivity studies of diamond samples. Using HOH as light source we measure the displacement current induced by excited electrons in the conduction band. Those electrons relax mainly by impact ionisation creating secondary electrons. Hence by probing the number of electrons we were able to measure the efficiency of these relaxation processes. We observe a diminution of this efficiency when the energy of exciting photons is above 20 eV. Owing to Monte-Carlo simulation we interpret this result in terms of band structure effect. (author)

  18. Role of temperature and energy density in the pulsed laser deposition of zirconium oxide thin film

    International Nuclear Information System (INIS)

    Mittra, Joy; Abraham, G.J.; Viswanadham, C.S.; Kulkarni, U.D.; Dey, G.K.

    2011-01-01

    Present work brings out the effects of energy density and substrate temperature on pulsed laser deposition of zirconium oxide thin film on Zr-base alloy substrates. The ablation of sintered zirconia has been carried out using a KrF excimer laser having 30 ns pulse width and 600 mJ energy at source at 10 Hz repetition rate. To comprehend effects of these parameters on the synthesized thin film, pure zirconia substrate has been ablated at two different energy densities, 2 J.cm -2 and 5 J.cm -2 , keeping the substrate at 300 K, 573 K and 873 K, respectively. After visual observation, deposited thin films have been examined using Raman Spectroscopy (RS) and X-ray Photo-electron Spectroscopy (XPS). It has been found that the oxide deposited at 300 K temperature does not show good adherence with the substrate and deteriorates further with the reduction in energy density of the incident laser. The oxide films, deposited at 573 K and 873 K, have been found to be adherent with the substrate and appear lustrous black. These indicate that the threshold for adherence of the zirconia film on the Zr-base alloy substrate lies in between 300 K and 573 K. Analysis of Raman spectra has indicated that thin films of zirconia, deposited using pulsed laser, on the Zr-base metallic substrate are initially in amorphous state. Experimental evidence has indicated a strong link among the degree of crystallinity of the deposited oxide film, the substrate temperature and the energy density. It also has shown that the crystallization of the oxide film is dependent on the substrate temperature and the duration of holding at high temperature. The O:Zr ratios of the films, analyzed from the XPS data, have been found to be close to but less than 2. This appears to explain the reason for the transformation of amorphous oxide into monoclinic and tetragonal phases, below 573 K, and not into cubic phase, which is reported to be more oxygen deficient. (author)

  19. N-type doping of InGaN by high energy particle irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Yu, K.M. [Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley CA, 94720 (United States)

    2009-06-15

    This article reviews our extensive studies of the effects of native defects introduced by high energy particles on the electrical and optical properties of InGaN alloys. We show that the electronic properties of irradiated InGaN can be well described by the amphoteric defect model. Because of the extremely low position of the conduction band edge of InN the formation energy of native donor defects is very low in In-rich InGaN alloys. High energy particle irradiation of InN and In-rich InGaN, will therefore produce donor defects and result in more n-type materials. As the irradiation dose increases, the electron concentration increases until the Fermi energy E{sub F} approaches the Fermi stabilization energy E{sub FS}. At this point both donor and acceptor-type defects are formed at similar rates, and compensate each other, leading to stabilization of E{sub F} and a saturation of the electron concentration. Hence a large increase and then saturation in the Burstein-Moss shift of the optical absorption edge is also observed. Furthermore we also found that mobilities in the irradiated films can be well described by scattering from triply charged defects, providing strong evidence that native defects in InN are triple donors. The excellent agreement between the experimental results and predictions based on the ADM suggests that particle irradiation can be an effective and simple method to control the doping (electron concentration) in In-rich In{sub x}Ga{sub 1-x}N via native point defects. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  20. N-type doping of InGaN by high energy particle irradiation

    International Nuclear Information System (INIS)

    Yu, K.M.

    2009-01-01

    This article reviews our extensive studies of the effects of native defects introduced by high energy particles on the electrical and optical properties of InGaN alloys. We show that the electronic properties of irradiated InGaN can be well described by the amphoteric defect model. Because of the extremely low position of the conduction band edge of InN the formation energy of native donor defects is very low in In-rich InGaN alloys. High energy particle irradiation of InN and In-rich InGaN, will therefore produce donor defects and result in more n-type materials. As the irradiation dose increases, the electron concentration increases until the Fermi energy E F approaches the Fermi stabilization energy E FS . At this point both donor and acceptor-type defects are formed at similar rates, and compensate each other, leading to stabilization of E F and a saturation of the electron concentration. Hence a large increase and then saturation in the Burstein-Moss shift of the optical absorption edge is also observed. Furthermore we also found that mobilities in the irradiated films can be well described by scattering from triply charged defects, providing strong evidence that native defects in InN are triple donors. The excellent agreement between the experimental results and predictions based on the ADM suggests that particle irradiation can be an effective and simple method to control the doping (electron concentration) in In-rich In x Ga 1-x N via native point defects. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)