Krypton excimer laser oscillation by discharge pumping

International Nuclear Information System (INIS)

Shirai, Takahiro; Tabe, Yoshitaka; Kubodera, Shoichi; Sasaki, Wataru; Kawanaka, Junji

2001-01-01

We have demonstrated vacuum ultraviolet (VUV) laser oscillation of the krypton excimer (Kr 2 *) excited by a compact self-sustained discharge device. We have observed a spectral narrowing of the Kr 2 * emission centered at 147.8 nm. A deconvoluted spectral width is 0.5 nm (FWHM), which reveals a contrast to a 13 nm spectral width of the spontaneous emission. The Kr 2 * intensity has increased one order of magnitude when a charging voltage was increased larger than 29 kV. The success of the lasing in the VUV spectral region has been attributed to the success of a stable glow discharge of Kr at 10 atm. The pulse width of the VUV laser radiation is 400 ns (FWHM). The maximum output energy measured is as large as 150 μJ. (author)

In Vitro and In Vivo Osteogenic Activity of Titanium Implants Coated by Pulsed Laser Deposition with a Thin Film of Fluoridated Hydroxyapatite

Directory of Open Access Journals (Sweden)

Luyuan Chen

2018-04-01

Full Text Available To enhance biocompatibility, osteogenesis, and osseointegration, we coated titanium implants, by krypton fluoride (KrF pulsed laser deposition, with a thin film of fluoridated hydroxyapatite (FHA. Coating was confirmed by scanning electron microscopy (SEM and scanning probe microscopy (SPM, while physicochemical properties were evaluated by attenuated reflectance Fourier transform infrared spectroscopy (ATR-FTIR. Calcium deposition, osteocalcin production, and expression of osteoblast genes were significantly higher in rat bone marrow mesenchymal stem cells seeded on FHA-coated titanium than in cells seeded on uncoated titanium. Implantation into rat femurs also showed that the FHA-coated material had superior osteoinductive and osseointegration activity in comparison with that of traditional implants, as assessed by microcomputed tomography and histology. Thus, titanium coated with FHA holds promise as a dental implant material.

Krypton tagging velocimetry of an underexpanded jet.

Science.gov (United States)

Parziale, N J; Smith, M S; Marineau, E C

2015-06-01

In this work, we present the excitation/emission strategy, experimental setup, and results of an implementation of krypton tagging velocimetry (KTV). KTV is performed as follows: (i) seed a base flow with krypton; (ii) photosynthesize metastable krypton atoms with a frequency-doubled dye laser to form the tagged tracer; (iii) record the translation of the tagged metastable krypton by imaging the laser-induced fluorescence (LIF) that is produced with an additional dye laser. The principle strength of KTV, relative to other tagging velocimetry techniques, is the use of a chemically inert tracer. KTV results are presented for an underexpanded jet of three mixtures of varying Kr/N2 concentration. It is demonstrated that KTV can be used in gas mixtures of relatively low krypton mole fraction (0.5% Kr/99.5% N2), and the KTV data from that experiment are found to be in good agreement with an empirical fit found in the literature. We find that KTV is useful to perform instantaneous velocity measurements with metastable krypton as a chemically inert, dilute, long-lifetime tracer in gas-phase flows.

[Krypton laser photocoagulation at low power setting for age-related macular degeneration complicated with subfoveal choroidal neovascularization].

Science.gov (United States)

Zhang, Cheng-fen; Jia, Yan; Li, Zhi-qing; Du, Hong; Han, Bao-ling

2004-12-01

To evaluate the efficacy of krypton laser photocoagulation for treatment of age-related macular degeneration (AMD) complicated with mainly subfoveal classic choroidal neovascularization (CNV). Seventeen eyes of 17 cases, aged 50 - 74 years (averaged 60.8 years) with mainly subfoveal classic choroidal neovascularization were treated with krypton laser at lower power setting. The treatment was completed in one session. Another course of treatment was given 4 weeks later if there was active leakage demonstrated at the CNV area. Visual acuity, anterior segment and fundus examination, perimetry test, fundus fluorescein angiography (FFA) and indocyanine green angiography (ICGA) were performed before and after treatment. The follow-up period was 3.5 years on average (1 - 8 years). There was no immediately decrease of visual acuity after treatment. All treated eyes showed absorption of hemorrhages and/or exudates and diminished leakages. Visual acuity was stable in 8 eyes; improved in 6 eyes (>/= 2 lines), and decreased in 3 eyes (Krypton laser photocoagulation at low power setting is an effective treatment for AMD with mainly classic subfoveal choroidal neovascularization.

Use of krypton laser stimulation in the treatment of dry eye syndrome

Science.gov (United States)

Kecik, Tadeusz; Switka-Wieclawska, Iwona; Ciszewska, Joanna; Portacha, Lidia

1991-08-01

We''d like to present the use of krypton laser stimulation in the treatment of dry eye syndrom. 10 patients with dry eye syndrom were treated with irradiation of the lacrimal gland. Schirmer test and break up time were performed before and after therapy. After 10 days of treatment we observed higher value of secreted tear amount.

Enamel-Caries Prevention Using Two Applications of Fluoride-Laser Sequence.

Science.gov (United States)

Noureldin, Amal; Quintanilla, Ines; Kontogiorgos, Elias; Jones, Daniel

2016-03-01

Studies demonstrated a significant synergism between fluoride and laser in reduction of enamel solubility. However, minimal research has focused on testing the sequence of their application and no other research investigated the preventive effect of repeated applications of a combined treatment. This study investigated the effect of two applications of fluoride-laser sequence on the resistance of sound enamel to cariogenic challenge compared to one-time application. Sixty enamel slabs were cut from 10 human incisors, ground flat, polished and coated with nail varnish except a 2 x 2 mm window. Specimens were randomly assigned into five groups of 12 specimens; (CON-) negative-control received no treatment, (CON+) positive-control received pH challenge, (FV) treated with M fluoride varnish, (F-L1) one-application fluoride-varnish followed by CO2 laser-treatment (short-pulsed 10.6 µm, 2.4J/ cm2, 10HZ, 10sec), and (F-L2) two-applications of fluoride varnish-laser treatment. Specimens were left in distilled water for one day between applications. Except CON-, all groups were submitted to pH cycling for 9-days (8 demin/ remin + 1 day remineralisation bath) at 37°C. Enamel demineralization was quantitatively evaluated by measurement of Knoop surface-microhardness (SM H) (50-grams/10 seconds). Data were analyzed using one-way ANOVA (p ≤ 0.05) followed by Duncan's Multiple Range Test. Within the limitations of this study, it was found that one or two applications of fluoride-laser sequence significantly improved resistance of the sound enamel surface to acid attack compared to FV-treated group. Although the two applications of fluoride-laser sequence (F-L1 and F-L2) showed higher SMH values, significant resistance to demineralization was only obtained with repeated applications.

Comparison of effects of diode laser and CO2 laser on human teeth and their usefulness in topical fluoridation.

Science.gov (United States)

González-Rodríguez, Alberto; de Dios López-González, Juan; del Castillo, Juan de Dios Luna; Villalba-Moreno, Juan

2011-05-01

Various authors have reported more effective fluoridation from the use of lasers combined with topical fluoride than from conventional topical fluoridation. Besides the beneficial effect of lasers in reducing the acid solubility of an enamel surface, they can also increase the uptake of fluoride. The study objectives were to compare the action of CO(2) and GaAlAs diode lasers on dental enamel and their effects on pulp temperature and enamel fluoride uptake. Different groups of selected enamel surfaces were treated with amine fluoride and irradiated with CO(2) laser at an energy power of 1 or 2 W or with diode laser at 5 or 7 W for 15 s each and compared to enamel surfaces without treatment or topical fluoridated. Samples were examined by means of environmental scanning electron microscopy (ESEM). Surfaces of all enamel samples were then acid-etched, measuring the amount of fluoride deposited on the enamel by using a selective ion electrode. Other enamel surfaces selected under the same conditions were irradiated as described above, measuring the increase in pulp temperature with a thermocouple wire. Fluorination with CO(2) laser at 1 W and diode laser at 7 W produced a significantly greater fluoride uptake on enamel (89 ± 18 mg/l) and (77 ± 17 mg/l) versus topical fluoridation alone (58 ± 7 mg/l) and no treatment (20 ± 1 mg/l). Diode laser at 5 W produced a lesser alteration of the enamel surface compared to CO(2) laser at 1 W, but greater pulp safety was provided by CO(2) laser (ΔT° 1.60° ± 0.5) than by diode laser (ΔT° 3.16° ± 0.6). Diode laser at 7 W and CO(2) laser at 2 W both caused alterations on enamel surfaces, but great pulp safety was again obtained with CO(2) (ΔT° 4.44° ± 0.60) than with diode (ΔT° 5.25° ± 0.55). Our study demonstrates that CO(2) and diode laser irradiation of the enamel surface can both increase fluoride uptake; however, laser energy parameters must be carefully

In Vitro Comparison of the Effects of Diode Laser and CO2 Laser on Topical Fluoride Uptake in Primary Teeth.

Science.gov (United States)

Bahrololoomi, Zahra; Fotuhi Ardakani, Faezeh; Sorouri, Milad

2015-08-01

Fluoride therapy is important for control and prevention of dental caries. Laser irradiation can increase fluoride uptake especially when combined with topical fluoride application. The objective of this study was to compare the effects of CO2 and diode lasers on enamel fluoride uptake in primary teeth. Forty human primary molars were randomly assigned to four groups (n=10). The roots were removed and the crowns were sectioned mesiodistally into buccal and lingual halves as the experimental and control groups. All samples were treated with 5% sodium fluoride (NaF) varnish. The experimental samples in the four groups were irradiated with 5 or 7W diode or 1 or 2W CO2 laser for 15 seconds and were compared with the controls in terms of fluoride uptake, which was determined using an ion selective electrode after acid dissolution of the specimens. Data were analyzed by SPSS version 16 using ANOVA treating the control measurements as covariates. The estimated amount of fluoride uptake was 59.5± 16.31 ppm, 66.5± 14.9 ppm, 78.6± 12.43 ppm and 90.4± 11.51 ppm for 5W and 7 W diode and 1W and 2 W CO2 lasers, respectively, which were significantly greater than the values in the conventional topical fluoridation group (Pdiode laser and 1W CO2 laser, 5W and 7W diode laser, or 1W and 2W CO2 laser in this regard. The results showed that enamel surface irradiation by CO2 and diode lasers increases the fluoride uptake.

Krypton fluoride laser mirror study. Final report, October 1978-November 1979

International Nuclear Information System (INIS)

Flint, B.K.; Najmi, A.; Stelmack, L.A.

1979-12-01

Rare gas halide lasers at 193 and 248/nm will require lower-loss optics if mirrors ad windows are not to be limiting factors in advanced DOE applications in laser fusion and photochemistry. This project addresses this problem in a number of ways, including materials investigations, test coatings, and fabrication of new uv laser coating designs, as described in more detail in the previous quarterly reports. Described in the final report are the process of making uv laser mirrors and the experimental strategy for attempting to improve them. Materials research is essential, and included selection and deposition of several condidate materials and an approximate ranking of their optical properties, so that new material combinations could be chosen, computer simulated, and deposited using improved vacuum techniques. Analysis of the electric fields within a laser mirror were employed to lower coating loss. A summary of test data is included, along with remarks on the survivability of uv laser optics, and possible future areas of inquiry, if truly low-loss uv laser mirrors are to ever be developed

Femtosecond two-photon laser-induced fluorescence of krypton for high-speed flow imaging.

Science.gov (United States)

Wang, Yejun; Capps, Cade; Kulatilaka, Waruna D

2017-02-15

Ultrashort-pulse (femtosecond-duration) two-photon laser-induced fluorescence (fs-TPLIF) of an inert gas tracer krypton (Kr) is investigated. A detailed spectroscopic study of fluorescence channels followed by the 5p'←←4p excitation of Kr at 204.1 nm is reported. The experimental line positions in the 750-840 nm emission region agree well with the NIST Atomic Spectra Database. The present work provides an accurate listing of relative line strengths in this spectral region. In the range of laser pulse energies investigated, a quadratic dependence was observed between the Kr-TPLIF signal and the laser pulse energy. The single-laser-shot 2D TPLIF images recorded in an unsteady jet demonstrate the potential of using fs excitation at 204.1 nm for mixing and flow diagnostic studies using Kr as an inert gas tracer.

Effect of CO2 Laser and Fluoride Varnish Application on Microhardness of Enamel Surface Around Orthodontic Brackets.

Science.gov (United States)

Mahmoudzadeh, Majid; Rezaei-Soufi, Loghman; Farhadian, Nasrin; Jamalian, Seyed Farzad; Akbarzadeh, Mahdi; Momeni, Mohammadali; Basamtabar, Masome

2018-01-01

Introduction: Orthodontic treatment has many advantages such as esthetic improvement and self-esteem enhancement; yet it has some disadvantages such as increasing the risk of formation of white spot lesions, because it makes oral hygiene more difficult. It is rational to implement procedures to prevent these lesions. The present study was aimed to assess the effect of CO 2 laser and fluoride varnish on the surface of the enamel surface microhardness around the orthodontic braces. Methods: Eighty extracted premolar teeth were selected, scaled, polished with nonfluoridated pumic and metal brackets were bonded to them. Then, they were randomly allocated to 5 groups: control (neither fluoride nor laser is used on enamel surfaces), fluoride (4 minutes fluoride varnish treatment of the enamel surfaces), CO 2 laser (10.6 µm CO 2 laser irradiation of the teeth), laserfluoride (fluoride application after laser irradiation) and fluoride-laser (fluoride was applied and then teeth were irradiated with laser). After surface treatment around brackets on enamel, the samples were stored in 0.1% thymol for less than 5 days and then they were exposed to a 10-day microbiological caries model. Microhardness values of enamel were evaluated with Vickers test. One sample of each group (5 teeth from 80 samples) was prepared for SEM (scanning electron microscopy) and the data from 75 remaining teeth were analyzed with analysis of variance (ANOVA) and chi-square tests (α =0.05). Results: Microhardness mean values from high to low were as follow: fluoride-laser, laser-fluoride, laser, fluoride and control. Microhardness in fluoride-laser group was significantly higher compared with that of the control group. Distribution adhesive remnant index (ARI) scores were significantly different between groups and most of bond failures occurred at the enamel-adhesive interface in groups 2 to 5 and at the adhesive-bracket interface in the control group. Conclusion: Combination of fluoride varnish and

Excimer laser development for fusion

International Nuclear Information System (INIS)

Giovanielli, D.

1985-01-01

The future utility of inertial confinement fusion requires a new driver. Successful experiments coupling laser energy to targets, and our understanding of fuel capsule behavior strongly suggest that a laboratory thermonuclear source is attainable and power production may be considered if a suitable driver with high efficiency, high repetition rate, and most importantly, low capital cost, can be identified. No adequate driver exists today; however, the krypton fluoride laser holds great promise. By the end of this decade, driver development can be brought to the point that a technically justifiable choice can be made for the future direction of ICF

Desorption/ablation of lithium fluoride induced by extreme ultraviolet laser radiation

Directory of Open Access Journals (Sweden)

Blejchař Tomáš

2016-06-01

Full Text Available The availability of reliable modeling tools and input data required for the prediction of surface removal rate from the lithium fluoride targets irradiated by the intense photon beams is essential for many practical aspects. This study is motivated by the practical implementation of soft X-ray (SXR or extreme ultraviolet (XUV lasers for the pulsed ablation and thin film deposition. Specifically, it is focused on quantitative description of XUV laser-induced desorption/ablation from lithium fluoride, which is a reference large band-gap dielectric material with ionic crystalline structure. Computational framework was proposed and employed here for the reconstruction of plume expansion dynamics induced by the irradiation of lithium fluoride targets. The morphology of experimentally observed desorption/ablation craters were reproduced using idealized representation (two-zone approximation of the laser fluence profile. The calculation of desorption/ablation rate was performed using one-dimensional thermomechanic model (XUV-ABLATOR code taking into account laser heating and surface evaporation of the lithium fluoride target occurring on a nanosecond timescale. This step was followed by the application of two-dimensional hydrodynamic solver for description of laser-produced plasma plume expansion dynamics. The calculated plume lengths determined by numerical simulations were compared with a simple adiabatic expansion (blast-wave model.

Clinical analysis of PASCAL laser and Krypton ion laser treatment of diabetic retinopathy%PASCAL激光与氪离子激光治疗糖尿病视网膜病变观察分析

Institute of Scientific and Technical Information of China (English)

董如娇; 陈芳; 李冬育; 赵霞; 董明霞

2014-01-01

Objective To evaluate the clinical efficacy difference of PASCAL laser and krypton ion laser treatment of diabetic retinopathy.Methods From June 2010 to June 2012 in The Eye hospital of Tangshan,200 cases (378 eyes) of pre-diabetic proliferative retinopathy and 200 cases (296 eyes) of proliferative diabetic retinopathy were randomly divided into PASCAL laser treatment groups and krypton ion laser treatment group.FFA,vision correction,and comfort questionnaire were re-examined three months after treatment.Results There were similar efficacy on promote avascular area subsided in patients with pre-proliferative diabetic retinopathy both using PASCAL laser and krypton ion laser treatment,the difference was not statistically significant.However,visual impairment was significantly less by PASCAL laser than krypton ion laser treatment (x2 27.562a,P 0.000,P ＜0.01),patients tolerated PASCAL laser significantly better than krypton ion laser (x21.940Ea,P 0.000,P ＜0.01),the above differences were statistically significant.The promoting neovascular regression role of PASCAL laser was weaker than krypton ion laser in the treatment of patients with proliferative diabetic retinopathy (x2-7.562a,P 0.000,P ＜0.01).PASCAL laser on visual impairment was significantly less than krypton ion laser (x2 13.408a,P 0.000,P ＜0.01),patients tolerated PASCAL laser significantly better than krypton ion laser (x2 1.025Ea,P 0.000,P ＜0.01),the above differences were statistically significant.Conclusions PASCAL laser compared with krypton ion laser treatment has some advantages in the early proliferative diabetic retinopathy,while the poor results in the treatment of proliferative diabetic retinopathy.%目的 探讨PASCAL激光与氪离子激光治疗糖尿病视网膜病变的临床疗效的差异.方法 对2010年6月至2012年6月在唐山市眼科医院就诊的200例增殖前期糖尿病视网膜病变患者378只眼;另外选取200例增殖期糖尿病视网膜病变患者296�

Study of krypton laser-induced choroidal neovascularization in a Guinea pig model of high anisometropia.

Science.gov (United States)

Wang, Jianghui; Jiang, Wei; Kang, Zefeng; Liang, Lina; Liu, Xiaoman; Tian, Nannan; Zhang, Qing

2012-06-01

To investigate the association between high anisometropia and the area of choroidal neovascularization (CNV) induced by krypton laser in guinea pigs and better understand the pathogenesis and prevention of myopic CNV. Nine 3-week old male guinea pigs with anisometropia >6.00D were randomly assigned to three groups according to examination date after laser photocoagulation (7d, 14d and 28d). All animals underwent refraction. The eye with higher myopia was used as the experimental eye, and the other as the control eye. All eyes received repeated multi-wavelength krypton laser photocoagulation treatments (wavelength: 532nm; laser power: 400mW; spot diameter: 50μm; exposure time: 0.1s). Fundus photography and indocyanine green angiography (ICGA) were performed. Afterwards, the animals were sacrificed immediately, and the eyes were enucleated and processed for histopathologic examination and flat mounts. CNV appeared at 7d after laser treatment. The area of CNV peaked at 14d, and decrease in area and the presence of scarring was noted at 28 d. CNV was present in 66.7% of eyes by ICGA at 14 d. CNV could be observed under light microscopy at all three time points. At 14d, flat mount showed the neovascular plexus around the lesion. Semi-quantitative analysis revealed that the area of CNV in treated eyes was greater than that of control eyes. Since the mechanism of CNV in this study resembles that of CNV in pathological myopia, this model can be used to investigate the etiology, pathogenesis and treatment of CNV in pathological myopia.

Generation of Multicharged Krypton Ions in Nanosecond Laser Ionization of Krypton Beam%纳秒激光电离产生Kr17+的研究

Institute of Scientific and Technical Information of China (English)

罗晓琳; 孔祥蕾; 牛冬梅; 渠洪波; 李海洋

2004-01-01

Up to Kr17+ muhicharged krypton ions have been observed in time-of-flight mass spectrum by a 25 ns Nd-YAG 1. 064 μm laser at laser intensity about 1012 W/cm2. Experimental results indicate that the muhicharged ions appear only when the laser interacts with the middle part of the pulsed beam, and the intensities of the multi charged ions increase dramatically by increasing the backing pressure of Kr gas, which indicates that the clusters in the beam is essential to the production of muhicharged ions. From the experimental results, it is concluded that the cluster is ionized via multiphoton ionization and forms a nanoplasma ball, which can absorb the laser resonantly to further ionize the single charge ion to the high charge state.

Analysis of krypton-85 and krypton-81 in a few liters of air.

Science.gov (United States)

Tu, Le-Yi; Yang, Guo-Min; Cheng, Cun-Feng; Liu, Gu-Liang; Zhang, Xiang-Yang; Hu, Shui-Ming

2014-04-15

Long-lived radioactive krypton isotopes, (81)Kr (t1/2 = 229,000 year) and (85)Kr (t1/2 = 10.76 year), are ideal tracers. (81)Kr is cosmogenic and can be used for dating groundwater beyond the (14)C age. (85)Kr is a fission product and can be applied in atmospheric studies, nuclear safety inspections, and dating young groundwater. It has long been a challenge to analyze radio-krypton in small samples, in which the total number of such isotopes can be as low as 1 × 10(5). This work presents a system developed to analyze (81)Kr and (85)Kr from a few liters of air samples. A separation system based on cryogenic distillation and gas chromatographic separation is used to extract krypton gas with an efficiency of over 90% from air samples of 1-50 L. (85)Kr/Kr and (81)Kr/Kr ratios in krypton gases are determined from single-atom counting using a laser-based atom trap. In order to test the performance of the system, we have analyzed various samples collected from ambient air and extracted from groundwater, with a minimum size of 1 L. The system can be applied to analyze (81)Kr and (85)Kr in environmental samples including air, groundwater, and ices.

Development of CO2 and KrF gas lasers as drivers for inertial confinement fusion

International Nuclear Information System (INIS)

Rockwood, S.D.

1983-01-01

Several different driver systems are currently under development in the national ICF program. Los Alamos has traditionally emphasized gas laser systems because of their intrinsic high average power capability and ease of operation. This paper will review the status of activities in both carbon dioxide (CO 2 ) and krypton fluoride (KrF) development at the Laboratory

The Effects of Remineralization via Fluoride Versus Low-Level Laser IR810 and Fluoride Agents on the Mineralization and Microhardness of Bovine Dental Enamel

Directory of Open Access Journals (Sweden)

Edith Lara-Carrillo

2018-01-01

Full Text Available The objective of this study was to assess the mineralization and microhardness of bovine dental enamel surfaces treated with fluoride, tri-calcium phosphate, and infrared (IR 810 laser irradiation. The study used 210 bovine incisors, which were divided into six groups (n = 35 in each: Group A: Untreated (control, Group B: Fluoride (Durapath-Colgate, Group C: Fluoride+Tri-calcium phosphate (Clin-Pro White-3 M, Group D: Laser IR 810 (Quantum, Group E: Fluoride+laser, and Group F: Fluoride+tri-calcium phosphate+laser. Mineralization was measured via UV-Vis spectroscopy for phosphorus and via atomic absorption spectroscopy for calcium upon demineralization and remineralization with proven agents. Microhardness (SMH was measured after enamel remineralization. Mineral loss data showed differences between the groups before and after the mineralizing agents were placed (p < 0.05. Fluoride presented the highest remineralization tendency for both calcium and phosphate, with a Vickers microhardness of 329.8 HV0.1/11 (p < 0.05. It was observed that, if remineralization solution contained fewer minerals, the microhardness surface values were higher (r = −0.268 and −0.208; p < 0.05. This study shows that fluoride has a remineralizing effect compared with calcium triphosphate and laser IR810. This in vitro study imitated the application of different remineralizing agents and showed which one was the most efficient for treating non-cavitated injuries. This can prevent the progression of lesions in patients with white spot lesions.

Resonantly-enhanced, four-photon ionization of krypton at laser intensities exceeding 1013 W/cm2

International Nuclear Information System (INIS)

Perry, M.D.; Landen, O.L.; Campbell, E.M.

1987-12-01

The yield of singly- and multiply- charged ions of krypton and xenon is presented as a function of laser intensity and frequency. The measurements were performed using the second harmonic output of a well-characterized, tunable picosecond dye laser in the range 285 to 310 nm at laser intensities from 1 x 10 12 to 10 14 W/cm 2 . Enhancement of the Kr + yield by two orders of magnitude by three-photon resonant, four-photon ionization is observed in the vicinity of the 4d'[5/2] 3 and the 4d[3/2] 1 intermediate states. A model incorporating line shifts and widths scaling linearly with intensity is in good agreement with the experimental results

A High-Energy Good-Beam-Quality Krypton-Lamp-Pumped Nd:YAG Solid-State Laser with One Pump Cavity

Institute of Scientific and Technical Information of China (English)

LIU Xue-Sheng; WANG Zhi-Yong; YAN Xin; CAO Ying-Hua

2008-01-01

We investigate a high-energy good-beam-quality krypton-lamp-pumped pulsed Nd:YAG solid-state laser with one pump cavity.The symmetrical resonator laser is developed and is rated at 80 J with beam parameter product 12mm mrad.The total system electro-optics efficiency of the lamp-pumped YAG laser is as high as 3.3% and the stability of output energy is ±2% with pulse width tunable between 0.1 ms and 10ms.The experimental results are consistent with the theoretical analysis and simulation.

Krypton yellow laser for the treatment of macular hole in high myopia without retinal detachment.

Science.gov (United States)

Cai, Ji-Ping; Cheng, Jin-Wei; Ma, Xiao-Ye; Li, Yu-Zhen; Li, You; Wei, Rui-Li

2008-12-01

To evaluate the prophylactic effect of krypton yellow laser for the treatment of macular holes in high myopic eyes in order to reduce the risk of retinal detachment. Twenty-seven eyes of 27 patients with high myopia and macular holes were randomly assigned to two groups. Fifteen patients (group A, 15 eyes) were subject to laser photocoagulation around the hole margin along with an oral placebo (vitamin B1), while 12 patients (group B, 12 eyes) were only given the oral placebo (vitamin B1). The incident rate of retinal detachment due to macular hole and the mean best-corrected visual acuity of the two groups before and after treatment were measured. The data were statistically tested by X2 test and Student's t test. The incident rates of retina1 detachment in group A and group B were 20%(3/15) and 58.3%(7/12), respectively (X2=4.201, P0.05). The mean BCVA of group B on the initial examination was 24/200, while the mean BCVA at the final follow-up was 30/200 (P>0.05). No significant difference in initial visual acuity (P>0.05) or final visual acuity (P>0.05) was found between the two groups. Krypton yellow laser photocoagulation could reduce the incidence of retinal detachment due to a macular hole in high myopia with acceptable functional results in this study.

Effects of the low-intensity red laser radiation on the fluoride uptake in enamel. A clinical trial

International Nuclear Information System (INIS)

Nakasone, Regina Keiko

2004-01-01

Fluoride has been the most important preventive method on development of the caries. This in vivo study evaluated the effects of low-intensity red laser radiation on the fluoride uptake in enamel. Ten healthy participants were recruited for this study. The two maxillary central incisors of each volunteer to be biopsied were used and divided into 4 groups: group G C (control, which was untreated; group G F (fluoride), which received topical acidulated phosphate fluoride (APF) 1,23% treatment for 4 minutes; group G LF (laser + fluoride), which was irradiated with a low-intensity diode laser (λ= 660 nm and dose= 6 J/cm 2 ) with APF application after irradiation and group G FL (fluoride + laser), which received APF before irradiation using the same parameters as G LF . The determination of fluoride was performed using a fluoride ion electrode after an acid-etch enamel biopsy. The results show a significant increase of the fluoride uptake in enamel for groups G F , G LF and G FL when compared to control group. Although a percentage increase of 57% was observed for G LF with respect to G F , there were no statistical differences among treated groups. These findings suggest that low-intensity laser radiation used before APF could be employed in the clinical practice to prevent dental caries. (author)

High-Pressure Reactivity of Kr and F2—Stabilization of Krypton in the +4 Oxidation State

Directory of Open Access Journals (Sweden)

Dominik Kurzydłowski

2017-10-01

Full Text Available Since the synthesis of the first krypton compound, several other Kr-bearing connections have been obtained. However, in all of them krypton adopts the +2 oxidation state, in contrast to xenon which forms numerous compounds with an oxidation state as high as +8. Motivated by the possibility of thermodynamic stabilization of exotic compounds with the use of high pressure (exceeding 1 GPa = 10 kbar, we present here theoretical investigations into the chemistry of krypton and fluorine at such large compression. In particular we focus on krypton tetrafluoride, KrF4, a molecular crystal in which krypton forms short covalent bonds with neighboring fluorine atoms thus adopting the +4 oxidation state. We find that this hitherto unknown compound can be stabilized at pressures below 50 GPa. Our results indicate also that, at larger compressions, a multitude of other KrmFn fluorides should be stable, among them KrF which exhibits covalent Kr–Kr bonds. Our results set the stage for future high-pressure synthesis of novel krypton compounds.

Design and performance characteristics of a krypton chloride (λ ...

Indian Academy of Sciences (India)

2014-01-07

Jan 7, 2014 ... Development of a discharge-pumped krypton chloride (KrCl) laser operating at 222 nm wavelength is demonstrated. In this paper the design, successful realization and operating characteristics of KrCl excimer laser are reported. The laser is driven by a simple and efficient excitation technique using ...

Krypton isotope analysis using near-resonant stimulated Raman spectroscopy

International Nuclear Information System (INIS)

Whitehead, C.A.; Cannon, B.D.; Wacker, J.F.

1994-12-01

A method for measuring low relative abundances of 85 Kr in one liter or less samples of air has been under development here at Pacific Northwest Laboratory. The goal of the Krypton Isotope Laser Analysis (KILA) method is to measure ratios of 10 -10 or less of 85 Kr to more abundant stable krypton. Mass spectrometry and beta counting are the main competing technologies used in rare-gas trace analysis and are limited in application by such factors as sample size, counting times, and selectivity. The use of high-resolution lasers to probe hyperfine levels to determine isotopic abundance has received much attention recently. In this study, we report our progress on identifying and implementing techniques for trace 85 Kr analysis on small gas samples in a static cell as well as limitations on sensitivity and selectivity for the technique. High-resolution pulsed and cw lasers are employed in a laser-induced fluorescence technique that preserves the original sample. This technique, is based on resonant isotopic depletion spectroscopy (RIDS) in which one isotope is optically depleted while preserving the population of a less abundant isotope. The KILA method consists of three steps. In the first step, the 1s 5 metastable level of krypton is populated via radiative cascade following two-photon excitation of the 2p 6 energy level. Next, using RBDS, the stable krypton isotopes are optically depleted to the ground state through the 1s 4 level with the bulk of the 85 Kr population being preserved. Finally, the remaining metastable population is probed to determine 85 Kr concentration. The experimental requirements for each of these steps are outlined below

The Nike KrF laser facility: Performance and initial target experiments

Science.gov (United States)

Obenschain, S. P.; Bodner, S. E.; Colombant, D.; Gerber, K.; Lehmberg, R. H.; McLean, E. A.; Mostovych, A. N.; Pronko, M. S.; Pawley, C. J.; Schmitt, A. J.; Sethian, J. D.; Serlin, V.; Stamper, J. A.; Sullivan, C. A.; Dahlburg, J. P.; Gardner, J. H.; Chan, Y.; Deniz, A. V.; Hardgrove, J.; Lehecka, T.; Klapisch, M.

1996-05-01

Krypton-fluoride (KrF) lasers are of interest to laser fusion because they have both the large bandwidth capability (≳THz) desired for rapid beam smoothing and the short laser wavelength (1/4 μm) needed for good laser-target coupling. Nike is a recently completed 56-beam KrF laser and target facility at the Naval Research Laboratory. Because of its bandwidth of 1 THz FWHM (full width at half-maximum), Nike produces more uniform focal distributions than any other high-energy ultraviolet laser. Nike was designed to study the hydrodynamic instability of ablatively accelerated planar targets. First results show that Nike has spatially uniform ablation pressures (Δp/pNike laser in producing uniform illumination, and its performance in correspondingly uniform acceleration of targets.

Efficacy of krypton laser photodynamic therapy for oral mucosa dysplasia in 9,10-dimethyl-1,2-benzanthracene-treated hamsters.

Science.gov (United States)

Shen, Lingyue; Xu, Qing; Li, Pingping; Zhou, Guoyu

2013-11-01

The present study aimed to evaluate the efficacy of krypton laser photodynamic therapy (PDT) with PsD-007 for the treatment of oral mucosa dysplasia in 9,10-dimethyl-1,2-benzanthracene (DMBA)-treated hamsters. A DMBA-induced hamster cheek pouch model of precancerous lesions was created and the resultant 25 hamsters were divided into five groups. The right side was treated with PDT and the left side was used as the positive control. Following systemic anesthesia, an incision was made in the groin area to expose the femoral vein. PsD-007 was administered intravenously through the femoral vein. Various doses of photosensitizer were used to treat groups A-E. Subsequent to closing the incision, the right side of the buccal mucosa was irradiated with light using the krypton laser at a wavelength of 413 nm, a power density of 150 mW/cm 2 and an irradiation time of 20 min. At six weeks post-surgery, the response was analyzed using histological examinations of the buccal pouch mucosa. A total of 24 hamsters completed the six-week observation period, as one hamster from group C died in the second week following the PDT. Of all 24 irradiated sides, 15 formed normal mucosal tissues and nine demonstrated mild dysplasia. Of the total control sides, six developed moderate dysplasia, five developed severe dysplasia and 13 progressed to carcinoma in situ or squamous cell carcinoma (SCC). The results revealed a significant difference between the two sides (P10 mg/kg, there was no statistical difference (P>0.05). PsD-007-mediated krypton laser PDT is effective for the treatment of oral mucosa dysplasia in hamsters.

An overview of Aurora: a multi-kilojoule KrF laser system for inertial confinement fusion

International Nuclear Information System (INIS)

Rosocha, L.A.; Bowling, P.S.; Burrows, M.D.; Kang, M.; Hanlon, J.; McLeod, J.; York, G.W.

1986-01-01

Aurora is a short-pulse high-power krypton-fluoride laser system that serves as an end-to-end technology demonstration prototype for large-scale ultraviolet laser systems of interest for short wavelength inertial confinement fusion (ICF) studies. The system is designed to employ optical angular multiplexing and serial amplification by electron-beam-driven KrF laser amplifiers to deliver 248 nm, 5-ns duration multi-kilojoule laser pulses to ICF targets using a beam train of approximately 1 km in length. The goals for the system are discussed and the design features of the major system components: front-end lasers, amplifier train, and the alignment and controls systems are summarised. (author)

Krypton purification (1961); Purification du krypton (1961)

Energy Technology Data Exchange (ETDEWEB)

Larher, Y [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Institut Fourier, 38 - Grenoble (France)

1961-07-01

The amount of xenon in otherwise very pure krypton can be reduced from 1.5 to 0.0025 per cent approximately by passage through an activated carbon column at dry-ice temperature. The circulation of the krypton is effected by condensing at -196 deg. C and then evaporating. (author) [French] Le taux de xenon dans du krypton par ailleurs tres pur est ramene de 1,5 pour cent a 0,0025 pour cent environ au cours d'un passage a travers une colonne de charbon actif a la temperature de la carboglace. La circulation du krypton se fait par condensation a -196 deg. C, puis evaporation. (auteur)

Mixture-fraction imaging at 1  kHz using femtosecond laser-induced fluorescence of krypton.

Science.gov (United States)

Richardson, Daniel R; Jiang, Naibo; Stauffer, Hans U; Kearney, Sean P; Roy, Sukesh; Gord, James R

2017-09-01

Femtosecond, two-photon-absorption laser-induced-fluorescence (TALIF) imaging measurements of krypton (Kr) are demonstrated to study mixing in gaseous flows. A measurement approach is presented in which observed Kr TALIF signals are 7 times stronger than the current state-of-the-art methodology. Fluorescence emission is compared for different gas pressures and excitation wavelengths, and the strongest fluorescence signals were observed when the excitation wavelength was tuned to 212.56 nm. Using this optimized excitation scheme, 1-kHz, single-laser-shot visualizations of unsteady flows and two-dimensional measurements of mixture fraction and scalar dissipation rate of a Kr-seeded jet are demonstrated.

Krypton-enhanced ventilation CT with dual energy technique: experimental study for optimal krypton concentration.

Science.gov (United States)

Chung, Yong Eun; Hong, Sae Rom; Lee, Mi-Jung; Lee, Myungsu; Lee, Hye-Jeong

2014-11-01

To assess the feasibility of krypton-enhanced ventilation CT using dual energy (DE) technique for various krypton concentrations and to determine the appropriate krypton concentration for DE ventilation CT through an animal study. Baseline DECT was first performed on seven New Zealand white rabbits. The animals were then ventilated using 20%, 30%, 40%, 50%, 60%, to 70% krypton concentration, and DECT was performed for each concentration. Krypton extraction was performed through a workstation, and results were displayed on a color map. Overlay Hounsfield unit (HU) values were obtained by two observers in consensus readings. A linear mixed model was used to correlate overlay HU values and krypton concentrations. Visual assessments of the homogeneity of krypton maps were also performed. Mean overlay HU values according to krypton concentration were as follows; 20% krypton, 1.68 ± 5.15; 30% krypton, 3.73 ± 5.93; 40% krypton, 6.92 ± 5.51; 50% krypton, 10.88 ± 5.17; 60% krypton, 14.54 ± 4.23; and 70% krypton, 18.79 ± 3.63. We observed a significant correlation between overlay HU values on krypton maps and krypton concentrations (P krypton color maps, all observers determined universal enhancement on the 70% krypton map for all animals. It is feasible to evaluate lung ventilation function using DECT with a krypton concentration of at least 70%.

Effect of pretreatment with an Er:YAG laser and fluoride on the prevention of dental enamel erosion.

Science.gov (United States)

dos Reis Derceli, Juliana; Faraoni-Romano, Juliana Jendiroba; Azevedo, Danielle Torres; Wang, Linda; Bataglion, César; Palma-Dibb, Regina Guenka

2015-02-01

The aim of this study was to evaluate the effect of the Er:YAG laser and its association with fluoride (1.23% acidulate phosphate fluoride gel) on the prevention of enamel erosion. Sixty specimens were obtained from bovine enamel (4 × 4 mm), which were ground flat, polished, and randomly divided into five groups according to the preventive treatments: control-fluoride application; L--Er:YAG laser; L+F--laser + fluoride; F+L--fluoride + laser; L/F--laser/fluoride simultaneously. Half of the enamel surface was covered with nail varnish (control area), and the other half was pretreated with one of the preventive strategies to subsequently be submitted to erosive challenge. When the laser was applied, it was irradiated for 10 s with a focal length of 4 mm and 60 mJ/2 Hz. Fluoride gel was applied for 4 min. Each specimen was individually exposed to regular Coca-Cola® for 1 min, four times/day, for 5 days. Wear analysis was performed with a profilometer, and demineralization was assessed with an optical microscope. Data were analyzed using the Kruskal-Wallis test (wear)/Dunn test and ANOVA/Fisher's exact tests. The group L/F was similar to control group. The other groups showed higher wear, which did not present differences among them. In the demineralization assessment, the groups F+L and L/F showed lower demineralization in relation to the other groups. It can be concluded that none preventive method was able to inhibit dental wear. The treatments L/F and F+L showed lower enamel demineralization.

Laser plasma instability experiments with KrF lasers

International Nuclear Information System (INIS)

Weaver, J. L.; Karasik, M.; Serlin, V.; Obenschain, S.; Chan, L-Y.; Kehne, D.; Schmitt, A. J.; Colombant, D.; Velikovich, A.; Oh, J.; Lehmberg, R. H.; Afeyan, B.; Phillips, L.; Seely, J.; Brown, C.; Feldman, U.; Aglitskiy, Y.; Mostovych, A. N.; Holland, G.

2007-01-01

Deleterious effects of laser-plasma instability (LPI) may limit the maximum laser irradiation that can be used for inertial confinement fusion. The short wavelength (248 nm), large bandwidth, and very uniform illumination available with krypton-fluoride (KrF) lasers should increase the maximum usable intensity by suppressing LPI. The concomitant increase in ablation pressure would allow implosion of low-aspect-ratio pellets to ignition with substantial gain (>20) at much reduced laser energy. The proposed KrF-laser-based Fusion Test Facility (FTF) would exploit this strategy to achieve significant fusion power (150 MW) with a rep-rate system that has a per pulse laser energy well below 1 MJ. Measurements of LPI using the Nike KrF laser are presented at and above intensities needed for the FTF (I∼2x10 15 W/cm 2 ). The results to date indicate that LPI is indeed suppressed. With overlapped beam intensity above the planar, single beam intensity threshold for the two-plasmon decay instability, no evidence of instability was observed via measurements of (3/2)ω o and (1/2)ω o harmonic emissions

Polymer optical fiber Bragg grating inscription with a single UV laser pulse

DEFF Research Database (Denmark)

Pospori, Andreas; Marques, A.T.; Bang, Ole

2017-01-01

We experimentally demonstrate the first polymer optical fiber Bragg grating inscribed with only one krypton fluoride laser pulse. The device has been recorded in a single-mode poly(methyl methacrylate) optical fiber, with a core doped with benzyl dimethyl ketal for photosensitivity enhancement. One...... laser pulse with a duration of 15 ns, which provide energy density of 974 mJ/cm2, is adequate to introduce a refractive index change of 0.74×10-4 in the fiber core. After the exposure, the reflectivity of the grating increases for a few minutes following a second order exponential saturation...

Laser technologies. KrF laser

International Nuclear Information System (INIS)

Owadano, Yoshiro; Okuda, Isao; Matsushima, Isao; Yashiro, Hidehiko; Matsumoto, Yuji

1994-01-01

Krypton-fluoride (KrF) laser is one of the promising driver for inertial confinement fusion because of its short wavelength, broad band width, high efficiency and capability of high repetition-rate operation. A high gain double-pass amplifier can yield a high, heavily saturated output intensity (5 to 6 times saturation intensity, > 10MW/cm 2 ) with nearly maximum efficiency (> 10%) and high stage gain (> 50) at the same time. The high gain can be achieved by cylindrical electron-beam pumping configuration without external magnetic field. Angular pulse multiplexing enables efficient pulse compression and amplification of beams with broad spectral width. The broad band width is required for irradiation smoothing methods, BRP (broad-band Random Phase Irradiation) or ISI (Induced Spatial Incoherence). Multi-kJ KrF laser, Super-ASHURA (Electrotechnical Laboratory, 8kJ), NIKE (at Naval Research Laboratory, 3kJ) and TITANIA (Rutherford Appleton Laboratory, 2kJ) are being developed and close to completion. (author)

In vitro study of demineralization resistance and fluoride retention in dental enamel irradiated with Er,Cr: YSGG laser

International Nuclear Information System (INIS)

Ana, Patricia Aparecida da.

2007-01-01

This study aimed to establish irradiation conditions of Er,Cr:YSGG laser (λ of 2.79 μm) which could propitiate changes on human dental enamel and increase its resistance to demineralization, when associated or not with topical application of acidulated phosphate fluoride (APF). Fluences of 2,8 J/cm 2 , 5,6 J/cm 2 e 8,5 J/cm 2 were selected; they were associated or not with previous application of a photo absorber (coal paste) and then APF was applied or not after laser irradiation. In a first step, the morphological findings, the surface temperatures, and the pupal temperatures were evaluated during laser irradiation. After that, the treated samples were submitted to a a ten-day pH-cycling model. After producing the incipient white-spots lesions, the following aspects were evaluated: the mineral loss, the loosely bound fluoride and the firmly bound fluoride. All the demineralizing and remineralizing pH-cycling solutions were evaluated with respect to their calcium (Ca), inorganic phosphorous (Pi) and fluoride (F - ) concentrations. The data had their normality and homogeneity distribution statistically evaluated, and it was chosen an appropriated statistical test for each performed analysis according to the obtained results, considering 5% significant level. The fluences selected for this study created ablated surfaces; the fluences of 5.6 J/cm 2 and 8.5 J/cm 2 promoted increments in surface temperature above 110 deg C. The intrapupal temperature changes revealed that laser irradiation did not increase the pulpal temperatures above the critical threshold for induction of pulpitis. The coal paste did not promote any changes on surface morphology or in the intrapulpal temperature changes; however, this paste increased the surface temperatures during laser irradiation. Only laser irradiation at 8.5 J/cm 2 was able to decrease the mineral loss when compared to the no-treatment group; although the association of coal paste + laser at 2.8 J/cm 2 + APF application

Development of a hydrogen fluoride laser

International Nuclear Information System (INIS)

Schilling, P.

1974-01-01

A hydrogen fluoride laser with variable pulse width (9 to 25 ns) was developed for measurements of shortlived dense plasmas. This multi-line laser with lambda approximately 2.9 μm operates without an optical pulse cutting system. Peak power of the pulses is about 400 kW. Measurements concerning dependence of FWHA, peak power and energy yield were carried out. Combined with an amplifier of 1 m length, peak power up to 13 MW and energies up to 0.5 J are attained. With this system, time dependence of the power amplification in the amplifier was tested for various gas mixtures. Furthermore preliminary measurements with time-resolved schlieren interferometry with this system are discussed. A plasma focus device was used as test object. (orig.) [de

Los Alamos KrF laser program

International Nuclear Information System (INIS)

Jensen, R.J.; Cartwright, D.C.

1985-01-01

Los Alamos is currently developing the krypton fluoride (KrF) laser - a highly efficient laser able to emit very intense bursts of short-wavelength photons - as a research tool for the general study of high-density matter, as well as for use in laser fusion. The KrF laser operates at 1/4 μm, close to the short-wavelength limit for conventional optical material, but still in the region where standard optical techniques can be used. The excited-state lifetime of the KrF lasing medium is short - as a result of both spontaneous emission and deactivation from collisions - making it impossible to store energy within the lasing medium for times significant to electrical pumping. However, an optical multiplexing scheme is being developed that will generate short, intense pulses of 1/4-μm light by overcoming the short storage time of the laser and taking advantage of the high gain of the KrF medium

Thermal stability of the krypton Hall effect thruster

Directory of Open Access Journals (Sweden)

Szelecka Agnieszka

2017-03-01

Full Text Available The Krypton Large IMpulse Thruster (KLIMT ESA/PECS project, which has been implemented in the Institute of Plasma Physics and Laser Microfusion (IPPLM and now is approaching its final phase, was aimed at incremental development of a ~500 W class Hall effect thruster (HET. Xenon, predominantly used as a propellant in the state-of-the-art HETs, is extremely expensive. Krypton has been considered as a cheaper alternative since more than fifteen years; however, to the best knowledge of the authors, there has not been a HET model especially designed for this noble gas. To address this issue, KLIMT has been geared towards operation primarily with krypton. During the project, three subsequent prototype versions of the thruster were designed, manufactured and tested, aimed at gradual improvement of each next exemplar. In the current paper, the heat loads in new engine have been discussed. It has been shown that thermal equilibrium of the thruster is gained within the safety limits of the materials used. Extensive testing with both gases was performed to compare KLIMT’s thermal behaviour when supplied with krypton and xenon propellants.

Observation of LPI Thresholds for the Nike Laser

Science.gov (United States)

Weaver, J. L.; Oh, J.; Afeyan, B.; Charbonneau-Lefort, M.; Phillips, L.; Seely, J.; Kehne, D.; Brown, C.; Obenschain, S.; Schmitt, A. J.; Feldman, U.; Holland, G.; Lehmberg, R. H.; McLean, E.; Manka, C.

2008-11-01

The Nike laser is being used to study thresholds for laser plasma instabilities (LPI) at intensities (10^15-10^16 W/cm^2) relevant to advanced implosion designs for direct drive inertial confinement fusion. The combination of short wavelength (248 nm), large bandwidth (1-2 THz), and beam smoothing by induced spatial incoherence available with this krypton-fluoride laser make these experiments unique among current facilities. This talk will present an overview of results with an emphasis on the two-plasmon decay instability (2φp). Measurements of x-rays and emission near ^1/2φo and ^3/2 φo harmonics of the laser wavelength have been collected over a wide range of intensities for both solid and foam targets. Data indicate collective multiple-angle driven excitation compatible with previous observations using solid planar targets.

Krypton Gas for High Quality Single Wall Carbon Nanotubes Synthesis by KrF Excimer Laser Ablation

Directory of Open Access Journals (Sweden)

Jasim Al-Zanganawee

2015-01-01

Full Text Available We report for the first time the production of single wall carbon nanotubes (SWCNTs by KrF excimer laser ablation method under the krypton gas atmosphere. For the ablation experiment 450 mJ energy and 30 Hz repetition rate KrF excimer laser was used, and the target was prepared with the following composition: 0.6% Ni, 0.6% Co, and 98.8% C (atomic percentage. The ablation product was characterized by confocal Raman microspectroscopy, transmission electron microscopy (TEM, scanning electron microscopy (SEM, and thermogravimetric analysis (TGA. The SWCNTs obtained are a mixture of semiconducting and metallic types with narrow diameters distribution of 1.26 to 1.49 nm, are micrometers long, and contain low amount of graphite and amorphous carbon.

Krypton separation from ambient air for application in collinear fast beam laser spectroscopy.

Science.gov (United States)

Mohamed, Tarek; Strohaber, James; Nava, Ricardo; Kolomenskii, Alexandre; Thonnard, Norbert; Schuessler, Hans A

2012-07-01

A portable apparatus for the separation of krypton from environmental air samples was tested. The apparatus is based on the cryogenic trapping of gases at liquid nitrogen temperature followed by controlled releases at higher temperatures. The setup consists of a liquid nitrogen trap for the removal of H(2)O and CO(2), followed by charcoal-filled coils that sequentially collect and release krypton and other gases providing four stages of gas chromatography to achieve separation and purification of krypton from mainly N(2), O(2), and Ar. Residual reactive gases remaining after the final stage of chromatography are removed with a hot Ti sponge getter. A thermal conductivity detector is used to monitor the characteristic elution times of the various components of condensed gases in the traps during step-wise warming of the traps from liquid nitrogen temperatures to 0 °C, and then to 100 °C. This allows optimizing the switching times of the valves between the stages of gas chromatography so that mainly krypton is selected and loaded to the next stage while exhausting the other gases using a He carrier. A krypton separation efficiency of ~80 % was determined using a quadrupole mass spectrometer.

8. High power laser and ignition facilities

International Nuclear Information System (INIS)

Bayramian, A.J.; Beach, R.J.; Bibeau, C.

2002-01-01

This document gives a review of the various high power laser projects and ignition facilities in the world: the Mercury laser system and Electra (Usa), the krypton fluoride (KrF) laser and the HALNA (high average power laser for nuclear-fusion application) project (Japan), the Shenguang series, the Xingguang facility and the TIL (technical integration line) facility (China), the Vulcan peta-watt interaction facility (UK), the Megajoule project and its feasibility phase: the LIL (laser integration line) facility (France), the Asterix IV/PALS high power laser facility (Czech Republic), and the Phelix project (Germany). In Japan the 100 TW Petawatt Module Laser, constructed in 1997, is being upgraded to the world biggest peta-watt laser. Experiments have been performed with single-pulse large aperture e-beam-pumped Garpun (Russia) and with high-current-density El-1 KrF laser installation (Russia) to investigate Al-Be foil transmittance and stability to multiple e-beam irradiations. An article is dedicated to a comparison of debris shield impacts for 2 experiments at NIF (national ignition facility). (A.C.)

Performance of the Aurora KrF ICF laser system

International Nuclear Information System (INIS)

Jones, J.E.; Czuchlewski, S.J.; Turner, T.P.; Watt, R.G.; Thomas, S.J.; Netz, D.A.; Tallman, C.R.; Mack, J.M.; Figueira, J.F.

1990-01-01

Because short wavelength lasers are attractive for inertial confinement fusion (ICF), the Department of Energy is sponsoring work at Los Alamos National Laboratory in krypton-fluoride (KrF) laser technology. Aurora is a short-pulse, high-power, KrF laser system. It serves as an end-to-end technology demonstration prototype for large-scale ultraviolet laser systems for short wavelength ICF research. The system employs optical angular multiplexing and serial amplification by electron-beam-driven KrF laser amplifiers. The 1 to 5 ns pulse of the Aurora front end is split into 96 beams which are angularly and temporally multiplexed to produce a 480 ns pulse train for amplification by four KrF laser amplifiers. In the present system configuration half (48) of the amplified pulses are demultiplexed using different optical path lengths and delivered simultaneously to target. This paper discusses how the Aurora laser system has entered the initial operational phase by delivering pulse energies of greater than one kilojoule to target

Acquired acid resistance of human enamel treated with laser (Er:YAG laser and Co 2 laser and acidulated phosphate fluoride treatment: An in vitro atomic emission spectrometry analysis

Directory of Open Access Journals (Sweden)

Anju Mathew

2013-01-01

Full Text Available Background: Dental caries is essentially a process of diffusion and dissolution. If the aspect of dissolution can be curtailed some degree of prevention can be achieved. Aims: The present study was carried out to evaluate and compare the effect of Er:YAG laser and Co 2 laser irradiation combined with acidulated phosphate fluoride treatment on in vitro acid resistance of human enamel. Design: An in vitro study was carried out on 30 human premolars to evaluate the enamel′s acid resistance using an atomic emission spectrometry analysis. Materials and Methods: A total of 60 enamel specimens were prepared from 30 human premolars and were randomly assigned to 6 groups: (1 Untreated (control; (2 1.23% acidulated phosphate fluoride (APF gel application alone for 4 min; (3 Er:YAG laser treatment alone; (4 Co 2 laser treatment alone; (5 Er:YAG laser + APF gel application; (6 Co 2 laser + APF gel application. The specimens were then individually immersed in 5 ml of acetate buffer solution (0.1 mol/L, pH 4.5 and incubated at 37°C for 24 h, and the acid resistance was evaluated by determining the calcium ion concentration using the atomic emission spectrometry. Statistical Analysis: An ANOVA model was constructed (P value of 0.05, followed by Tukey′s test for multiple pair wise comparisons of mean values. Results: Significant differences were found between the control group and the test groups ( P < 0.001. Conclusions: Combining acidulated phosphate fluoride with either Er:YAG or Co 2 laser had a synergistic effect in decreasing the enamel demineralization more than either fluoride treatment or laser treatment alone.

Synergistic effect of fluoride and laser irradiation for the inhibition of the demineralization of dental enamel

Science.gov (United States)

Lee, Raymond; Chan, Kenneth H.; Jew, Jamison; Simon, Jacob C.; Fried, Daniel

2017-02-01

Both laser irradiation and fluoride treatment alone are known to provide increased resistance to acid dissolution. CO2 lasers tuned to a wavelength of 9.3 μm can be used to efficiently convert the carbonated hydroxyapatite of enamel to a much more acid resistant purer phase hydroxyapatite (HAP). Further studies have shown that fluoride application to HAP yields fluoroapatite (FAP) which is even more resistant against acid dissolution. Previous studies show that CO2 lasers and fluoride treatments interact synergistically to provide significantly higher protection than either method alone, but the mechanism of interaction has not been elucidated. We recently observed the formation of microcracks or a "crazed" zone in the irradiated region that is resistant to demineralization using high-resolution microscopy. The microcracks are formed due to the slight contraction of enamel due to transformation of carbonated hydroxyapatite to the more acid resistant pure phase hydroxyapatite (HAP) that has a smaller lattice. In this study, we test the hypothesis that these small cracks will provide greater adhesion for topical fluoride for greater protection against acid demineralization.

Quenching of the resonance 5s({sup 3}P{sub 1}) state of krypton atoms in collisions with krypton and helium atoms

Energy Technology Data Exchange (ETDEWEB)

Zayarnyi, D A; L' dov, A Yu; Kholin, I V [P N Lebedev Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation)

2014-11-30

The processes of collision quenching of the resonance 5s[3/2]{sub 1}{sup o}({sup 3}P{sub 1}) state of the krypton atom are studied by the absorption probe method in electron-beam-excited high-pressure He – Kr mixtures with a low content of krypton. The rate constants of plasmochemical reactions Kr* + Kr + He → Kr*{sub 2} + He [(4.21 ± 0.42) × 10{sup -33} cm{sup 6} s{sup -1}], Kr* + 2He → HeKr* + He [(4.5 ± 1.2) × 10{sup -36} cm{sup 6} s{sup -1}] and Kr* + He → products + He [(2.21 ± 0.22) × 10{sup -15} cm{sup 3} s{sup -1}] are measured for the first time. The rate constants of similar reactions are refined for krypton in the metastable 5s[3/2]{sub 2}{sup o} ({sup 3}P{sub 2}) state. (laser applications and other topics in quantum electronics)

Measurements of low-level prepulse on Nike KrF laser

International Nuclear Information System (INIS)

Karasik, Max; Mostovych, A.N.; Lehmberg, R.H.; Chan, Y.; Weaver, J.L.; Obenschain, S.P.

2005-01-01

The krypton fluoride (KrF) laser is a leading candidate driver for inertial fusion energy. Some of the current fusion target designs call for targets with thin metallic coatings. These targets could be particularly susceptible to preheat by a low-level laser prepulse. Knowledge of the prepulse can be important in understanding and modeling the behavior of such targets. This paper presents measurements of low-level prepulse on target with the Nike KrF laser. Sources of prepulse are discussed and measurements are performed under several specific laser conditions in order to evaluate the relative contribution of these sources to the overall prepulse. Prepulse is found to be ∼2x10 -7 from peak intensity for approximately 120 ns prior to the main laser pulse. Prepulse energy density on target is ∼2 J/cm 2 . The first laser amplifier in the time- and angle-multiplexed section of the laser is found to be the dominant source of prepulse

Aurora laser optical system

International Nuclear Information System (INIS)

Hanlon, J.A.; McLeod, J.

1987-01-01

Aurora is the Los Alamos short-pulse high-power krypton fluoride laser system. It is primarily an end-to-end technology demonstration prototype for large-scale UV laser systems of interest for short-wavelength inertial confinement fusion (ICF) investigations. The system is designed to employ optical angular multiplexing and aerial amplification by electron-beam-driven KrF laser amplifiers to deliver to ICF targets a stack of pulses with a duration of 5 ns containing several kilojoules at a wavelength of 248 nm. A program of high-energy density plasma physics investigations is now planned, and a sophisticated target chamber was constructed. The authors describe the design of the optical system for Aurora and report its status. This optical system was designed and is being constructed in two phases. The first phase carries only through the amplifier train and does not include a target chamber or any demultiplexing. Installation should be complete, and some performance results should be available. The second phase provides demultiplexing and carries the laser light to target. The complete design is reported

Study on the pathogenesis of transient intraocular pressure after laser iridectomy with Krypton laser combined with Q-switched Nd:YAG laser

Directory of Open Access Journals (Sweden)

Zhi-Juan Pei

2017-12-01

Full Text Available AIM: To study the pathogenesis of transient intraocular pressure(IOPafter laser iridectomy with Krypton laser combined with Q-switched Nd:YAG laser. METHODS: Totally 42 healthy rabbits(84 eyesprovided by the Animal Experimental Center of our hospital were selected, including 18 female rabbits, 24 male rabbits, average weight 2.24±0.31kg, and they were randomly divided into 6 groups, 7 rats in each group(14 eyes. We observed the change of intraocular pressure after laser iridectomy surgery at 20min, 2, 6, 18, 24h and the nitric oxide(NO, malondialdehyde(MDA, superoxide dismutase(SOD, 6-keto-prostaglandin(6-keto-PGF1αand nitric oxide synthase(NOScontent in aqueous. RESULTS: There was no significant difference in intraocular pressure, NO, NOS, SOD, MAD and 6-keto- PGF1α before operation(P>0.05. The intraocular pressure increased after operation, and the difference was statistically significant(PP>0.05. The levels of NO, NOS and SOD in the aqueous humor of the two groups decreased 20min, 2 and 6h after the operation(PP>0.05. The levels of MDA and 6-keto-prostaglandin in the aqueous humor increased after the operation, and the difference was statistically significant at 20min, 2 and 6h after operation(PP>0.05.CONCLUSION: The increase of transient intraocular pressure after laser iridectomy may relate to the increase of malondialdehyde, 6-keto-prostaglandin content and the decrease of superoxide dismutase and nitric oxide in the aqueous humor after operation.

虹膜切口氪激光预光凝在青光眼激光治疗中的临床研究%Clinical Research of Pre-photocoagulation of Iris Cut by Krypton Laser in Glaucoma Laser Treatment

Institute of Scientific and Technical Information of China (English)

张磊

2011-01-01

Objective To observe the effect of pre - photocoagulation iris by krypton laser in glaucoma laser treatment. Methods All 78 cases( 92 eyes )were grouped into A and B. Group A was treated by krypton laser peripheral iridoplasty( LPIP ), iris pre - photocoagulation and YAG laser peripheral iridectomy ( LPI ). Group B was only treated by LPIP and YAG LPI. After laser Treatment, IOP, visual acuity and iris haemorrhage were observed. Results The difference of IOP and iris haemorrhage between group A and group B was statistically significant( P ＜ 0.05 ). Conclusion The method of pre - thermocoagulation iris by krypton laser can reduce the complication of glaucoma laser treatment effectively.%目的 观察虹膜切口氪激光预光凝对青光眼激光治疗的影响.方法 将我院门诊需行激光治疗的青光眼患者78例(92只眼)随机分成A、B组.A组行虹膜氪激光周边成形+切口周围预光凝+YAG激光切开术.B组行虹膜氪激光周边成形+YAG激光切开术,治疗后观察两组的视力、眼压、虹膜出血等指标.结果 比较两组在治疗后眼压和虹膜出血等并发症情况的差异有统计学意义(P < 0.05).结论 氪激光虹膜切口预光凝可以有效地降低青光眼激光治疗后的并发症.

The Nike KrF laser facility: Performance and initial target experiments

International Nuclear Information System (INIS)

Obenschain, S.P.; Bodner, S.E.; Colombant, D.; Gerber, K.; Lehmberg, R.H.; McLean, E.A.; Mostovych, A.N.; Pronko, M.S.; Pawley, C.J.; Schmitt, A.J.; Sethian, J.D.; Serlin, V.; Stamper, J.A.; Sullivan, C.A.; Dahlburg, J.P.; Gardner, J.H.; Chan, Y.; Deniz, A.V.; Hardgrove, J.; Lehecka, T.; Klapisch, M.

1996-01-01

Krypton-fluoride (KrF) lasers are of interest to laser fusion because they have both the large bandwidth capability (approx-gt THz) desired for rapid beam smoothing and the short laser wavelength (1/4 μm) needed for good laser endash target coupling. Nike is a recently completed 56-beam KrF laser and target facility at the Naval Research Laboratory. Because of its bandwidth of 1 THz FWHM (full width at half-maximum), Nike produces more uniform focal distributions than any other high-energy ultraviolet laser. Nike was designed to study the hydrodynamic instability of ablatively accelerated planar targets. First results show that Nike has spatially uniform ablation pressures (Δp/p<2%). Targets have been accelerated for distances sufficient to study hydrodynamic instability while maintaining good planarity. In this review we present the performance of the Nike laser in producing uniform illumination, and its performance in correspondingly uniform acceleration of targets. copyright 1996 American Institute of Physics

Krypton laser-induced photothrombotic distal middle cerebral artery occlusion without craniectomy in mice.

Science.gov (United States)

Sugimori, Hiroshi; Yao, Hiroshi; Ooboshi, Hiroaki; Ibayashi, Setsuro; Iida, Mitsuo

2004-08-01

Recent advances in genetical engineering of the mouse have highlighted the importance of reproducible and less invasive models of cerebral ischemia in mice. In this paper, we developed minimally invasive and reproducible model of distal middle cerebral artery (MCA) occlusion in mice using krypton (Kr) laser-induced photothrombosis. C57BL/6 or BALB mice (n=8 each) were anesthetized with halothane. The skin was cut, the temporal muscle was retracted, and the right distal MCA was observed through the skull. A Kr laser beam of wavelength 568 nm was focused onto the MCA over the intact skull. Upon laser irradiation, intravenous administration of a rose bengal solution was begun. After 4 min of irradiation, the laser beam was refocused on the MCA just proximal to the first spot, and another 4-min irradiation was performed. Then, the right common carotid artery (CCA) was ligated. Three days later, the brain was removed, and infarct volume was determined. Infarction confined almost solely to the cortical area was produced in each mouse. Mean infarct volume in C57BL/6 mice was 25.2+/-13.7 mm3. The BALB mice group showed significantly larger and more reproducible infarction (44.1+/-5.2 mm3; the coefficient of variation was 12%) than did C57BL/6 mice (P<0.005). Our photothrombosis model of stroke in mice can be performed without craniectomy, and its reproducibility is satisfactory when using BALB mice.

Advances in Mid-IR Fiber Lasers: Tellurite, Fluoride and Chalcogenide

Directory of Open Access Journals (Sweden)

Mario Christian Falconi

2017-06-01

Full Text Available A review on the recent progress in modeling and fabrication of medium infrared (Mid-IR fiber lasers is reported. The main objective is to illustrate some recent examples of continuous wave optical sources at wavelengths longer than those commonly employed in telecom applications and allowing high beam quality. A small number of Mid-IR lasers, among the large variety of schemes, glasses, dopants and pumping schemes reported in literature, is selected on the basis of their slope efficiency and threshold pump power. In particular, tellurite, fluoride and chalcogenide fiber lasers are considered. More details are given with reference to the novel pumping schemes.

Radioactive krypton gas separation

International Nuclear Information System (INIS)

Martin, J.R.

1976-01-01

Radioactive krypton is separated from a gas mixture comprising nitrogen and traces of carbon dioxide and radioactive krypton by selective adsorption and then cryogenic distillation of the prepurified gas against nitrogen liquid to produce krypton bottoms concentrate liquid, using the nitrogen gas from the distillation for two step purging of the adsorbent. 16 Claims, 8 Drawing Figures

Impact of combined CO2 laser irradiation and fluoride on enamel and dentin biofilm-induced mineral loss.

Science.gov (United States)

Esteves-Oliveira, Marcella; El-Sayed, Karim Fawzy; Dörfer, Christof; Schwendicke, Falk

2017-05-01

The caries-protective effects of CO 2 laser irradiation on dental enamel have been demonstrated using chemical demineralization models. We compared the effect of CO 2 laser irradiation, sodium fluoride, or both on biofilm-induced mineral loss (∆Z) and Streptococcus mutans adhesion to enamel and dentin in vitro. Ground, polished bovine enamel, and dentin samples were allocated to four groups (n = 12/group): no treatment (C); single 22,600-ppm fluoride (F) varnish (5 % NaF) application; single CO 2 laser treatment (L) with short pulses (5 μs/λ = 10.6 μm); and laser and subsequent fluoride treatment (LF). Samples were sterilized and submitted to an automated mono-species S. mutans biofilm model. Brain heart infusion plus 5 % sucrose medium was provided eight times daily, followed by rinses with artificial saliva. After 10 days, bacterial numbers in biofilms were enumerated as colony-forming units/ml (CFU/ml) (n = 7/group). ∆Z was assessed using transversal microradiography (n = 12/group). Univariate ANOVA with post hoc Tukey honestly-significant-difference test was used for statistical analysis. Bacterial numbers were significantly higher on dentin than enamel (p  0.05). In dentin, only LF (163/227) significantly reduced ∆Z (p fluoride application was required to protect dentin.

Pramana – Journal of Physics | Indian Academy of Sciences

Indian Academy of Sciences (India)

2014-01-05

Jan 5, 2014 ... Keywords. Excimer; krypton fluoride; pre-ionization; spectral width; beam profile. Abstract. Studies related to the effect of pre-ionizer on laser output energy of a repetitively pulsed KrF laser are presented. The dependence of laser output energy, spectral width and beam spot homogeneity on pre-ionization ...

Innovative method for ultra-sensitive measurement of krypton isotopes

International Nuclear Information System (INIS)

Lavielle, B.; Gilabert, E.; Thomas, B.; Rebeix, R.; Canchel, G.; Moulin, C.; Topin, S.; Pointurier, F.

2015-01-01

Kr 81 (T 1/2 = 2.29*10 5 y), that is produced in the atmosphere by cosmic rays and Kr 85 (T 1/2 = 10.77 y), that is produced in the fission of nuclear fuels, are considered as the right chronometer elements for the dating of underground waters, polar ice, of for tracking civil and military nuclear activities. The use of Kr 81 and Kr 85 implies the development of extracting lines and detection devices with so high accuracy that only a few thousands of krypton atoms can be detected. The approach developed aims at detecting Kr 81 and Kr 85 in 1 liter of air and 20 liters of water. 3 steps are necessary. The first step consists in separating and purifying the krypton. The extraction of gases from water is made by helium bubbling. Chemically active gases like N 2 , CO 2 , CH 4 and O 2 are eliminated by chemical traps while Ar si separated by cryogenics. The second step involves a double focus mass spectrometer designed to perform an important enrichment in Kr 81 and Kr 85 . The last step is the high-accuracy measurement of krypton isotopes performed with the new tool named FAKIR (Facility for Analyzing Krypton Isotopic Ratios) that is based on UV laser ionization and on the mass-discrimination of the ions through their time of flight

Retention of krypton on polymethyl methacrylate

International Nuclear Information System (INIS)

Ciric, M.M.; Cvjeticanin, N.M.; Radak, B.B.

1975-01-01

Retention of krypton on polymethyl methacrylate was studied as a function of kryptonation pressure (P), temperature (T) and time (t). It was found that the dependence of the retained quantity on P, T, and t is in accordance with the diffusion theory. The optimum results (i.e., the maximum retained quantity and the best stability of the kryptonate) were obtained at elevated kryptonation temperatures (200 0 C). The diffusion coefficients of krypton in polymethyl methacrylate, determined from the dekryptonation process, vary from 1 x 10 -10 cm 2 /s to 0.2 x 10 -10 cm 2 /s for samples kryptonated at 20 0 C and 200 0 C respectively. The results have been discussed from the viewpoint of radiation and thermal stability of kryptonated polymethyl methacrylate. Inadequate radiation stability could be the main obstacle for practical purposes. (U.S.)

Krypton oxides under pressure

OpenAIRE

Zaleski-Ejgierd, Patryk; Łata, Paweł

2015-01-01

Under high pressure, krypton, one of the most inert elements is predicted to become sufficiently reactive to form a new class of krypton compounds; krypton oxides. Using modern ab-initio evolutionary algorithms in combination with Density Functional Theory, we predict the existence of several thermodynamically stable Kr/O species at elevated pressures. In particular, our calculations indicate that at approx. 300?GPa the monoxide, KrO, should form spontaneously and remain thermo- and dynamical...

Unique capabilities for ICF and HEDP research with the KrF laser

Science.gov (United States)

Obenschain, Stephen; Bates, Jason; Chan, Lop-Yung; Karasik, Max; Kehne, David; Sethian, John; Serlin, Victor; Weaver, James; Oh, Jaechul; Jenkins, Bruce; Lehmberg, Robert; Hegeler, Frank; Terrell, Stephen; Aglitskiy, Yefim; Schmitt, Andrew

2014-10-01

The krypton-fluoride (KrF) laser provides the shortest wavelength, broadest bandwidth and most uniform target illumination of all developed high-energy lasers. For directly driven targets these characteristics result in higher and more uniform ablation pressures as well as higher intensity thresholds for laser-plasma instability. The ISI beam smoothing scheme implemented on the NRL Nike KrF facility allows easy implementation of focal zooming where the laser radial profile is varied during the laser pulse. The capability for near continuous zooming with KrF would be valuable towards minimizing the effects of cross beam energy transport (CBET) in directly driven capsule implosions. The broad bandwidth ISI beam smoothing that is utilized with the Nike KrF facility may further inhibit certain laser plasma instability. In this presentation we will summarize our current understanding of laser target interaction with the KrF laser and the benefits it provides for ICF and certain HEDP experiments. Status and progress in high-energy KrF laser technology will also be discussed. Work supported by the Deparment of Energy, NNSA.

Progress on CBET Platform at the Nike Laser

Science.gov (United States)

Weaver, J. L.; McKenty, P.; Oh, J.; Kehne, D.; Schmitt, A. J.; Obenschain, S.; Serlin, V.; Lehmberg, R.; Tsung, F.

2015-11-01

Cross-beam energy transport (CBET) studies are underway at the Nike krypton-fluoride (KrF) laser at NRL. This facility has unique characteristics that provide an excellent platform for CBET work - including short wavelength (248 nm), large bandwidth (1-3 THz), beam smoothing by induced spatial incoherence (ISI), and full aperture focal spot zooming. Nike's two beam arrays are widely separated (135° in azimuth) which facilitates CBET studies in a nearly opposing geometry, relevant to Polar Direct Drive implosions. Various target types are planned: planar slabs, cylindrical and spherical shells, and low-density targets. The solid targets will be used to examine gradient geometries and the latter will access larger volume, more uniform plasmas. The initial campaign is exploring changes observed by scattered light diagnostics for both beam arrays as the probe laser spectrum is modified. Work supported by DoE/NNSA.

Effects of the low-intensity red laser radiation on the fluoride uptake in enamel. A clinical trial; Avaliacao dos efeitos da radiacao laser de emissao vermelha em baixa intensidade na incorporacao de fluor no esmalte. Estudo clinico

Energy Technology Data Exchange (ETDEWEB)

Nakasone, Regina Keiko

2004-07-01

Fluoride has been the most important preventive method on development of the caries. This in vivo study evaluated the effects of low-intensity red laser radiation on the fluoride uptake in enamel. Ten healthy participants were recruited for this study. The two maxillary central incisors of each volunteer to be biopsied were used and divided into 4 groups: group G{sub C} (control, which was untreated; group G{sub F} (fluoride), which received topical acidulated phosphate fluoride (APF) 1,23% treatment for 4 minutes; group G{sub LF} (laser + fluoride), which was irradiated with a low-intensity diode laser ({lambda}= 660 nm and dose= 6 J/cm{sup 2}) with APF application after irradiation and group G{sub FL} (fluoride + laser), which received APF before irradiation using the same parameters as G{sub LF}. The determination of fluoride was performed using a fluoride ion electrode after an acid-etch enamel biopsy. The results show a significant increase of the fluoride uptake in enamel for groups G{sub F}, G{sub LF} and G{sub FL} when compared to control group. Although a percentage increase of 57% was observed for G{sub LF} with respect to G{sub F}, there were no statistical differences among treated groups. These findings suggest that low-intensity laser radiation used before APF could be employed in the clinical practice to prevent dental caries. (author)

Double shock front formation in cylindrical radiative blast waves produced by laser irradiation of krypton gas

Energy Technology Data Exchange (ETDEWEB)

Kim, I.; Quevedo, H. J.; Feldman, S.; Bang, W.; Serratto, K.; McCormick, M.; Aymond, F.; Dyer, G.; Bernstein, A. C.; Ditmire, T. [Center for High Energy Density Science, Department of Physics, The University of Texas at Austin, C1510, Austin, Texas 78712 (United States)

2013-12-15

Radiative blast waves were created by irradiating a krypton cluster source from a supersonic jet with a high intensity femtosecond laser pulse. It was found that the radiation from the shock surface is absorbed in the optically thick upstream medium creating a radiative heat wave that travels supersonically ahead of the main shock. As the blast wave propagates into the heated medium, it slows and loses energy, and the radiative heat wave also slows down. When the radiative heat wave slows down to the transonic regime, a secondary shock in the ionization precursor is produced. This paper presents experimental data characterizing both the initial and secondary shocks and numerical simulations to analyze the double-shock dynamics.

Dentinal hypersensitivity following scaling and root planing: comparison of low-level laser and topical fluoride treatment.

Science.gov (United States)

Pesevska, Snezana; Nakova, Marija; Ivanovski, Kiro; Angelov, Nikola; Kesic, Ljiljana; Obradovic, Radmila; Mindova, Sonja; Nares, Salvador

2010-09-01

The aim of this study is to compare the effectiveness of low-level laser irradiation to traditional topical fluoride treatment for treatment choices of dentinal hypersensitivity following scaling and root planing. The experimental group (15 patients) was treated with low-energy-level diode laser at each site of dentinal hypersensitivity following scaling and root planning. The control group (15 patients) received topical fluoride treatment (protective varnish for desensitization). All the patients were treated at baseline visit, and then at day 2 and 4 after the initial treatment; the pain was subjectively assessed by the patients as strong, medium, medium low, low, or no pain. Total absence of the dental hypersensitivity was reported in 26.66% of the examined group even after the second visit, compared to the control group where complete resolution of the hypersensitivity was not present after the second visit in any of the treated cases. Complete absence of pain was achieved in 86.6% of patients treated with laser and only in 26.6% in the fluoride treated group, after the third visit. Based on our findings, we conclude that low-energy biostimulative laser treatment can be successfully used for treatment of dental hypersensitivity following scaling and root planing.

Krypton purification (1961)

International Nuclear Information System (INIS)

Larher, Y.

1961-01-01

The amount of xenon in otherwise very pure krypton can be reduced from 1.5 to 0.0025 per cent approximately by passage through an activated carbon column at dry-ice temperature. The circulation of the krypton is effected by condensing at -196 deg. C and then evaporating. (author) [fr

Development of fluorides for high power laser optics

International Nuclear Information System (INIS)

Ready, J.F.; Vora, H.

1980-07-01

The laser-assisted thermonuclear fusion program has significant needs for improved optical materials with high transmission in the ultraviolet, and with low values of nonlinear index of refraction. Lithium fluoride (LiF) possesses a combination of optical properties which are of potential use. Single-crystalline LiF is limited by low mechanical strength. In this program, we investigated the technique of press-forging to increase the mechanical strength. LiF single crystals were press-forged over the temperature range 300 to 600 0 C to produce fine-grained polycrystalline material

Review of ultraviolet damage threshold measurements at Lawrence Livermore National Laboratory

Energy Technology Data Exchange (ETDEWEB)

Lowdermilk, W.H.; Milam, D.

1984-01-01

The results of damage threshold measurements made at LLNL using ultraviolet wavelength laser pulses are reviewed. Measurements were made with pulses from a krypton fluoride laser with wavelength of 248 nm and pulse duration of 20 ns and with Nd-glass laser pulses converted to the third harmonic wavelength of 355 nm with duration of 0.6 ns. Measurements are presented for transparent window materials, crystals and harmonic generation, single layer dielectric films of oxide and fluoride materials and multilayer high reflectivity and antireflective coatings.

Review of ultraviolet damage threshold measurements at Lawrence Livermore National Laboratory

International Nuclear Information System (INIS)

Lowdermilk, W.H.; Milam, D.

1984-01-01

The results of damage threshold measurements made at LLNL using ultraviolet wavelength laser pulses are reviewed. Measurements were made with pulses from a krypton fluoride laser with wavelength of 248 nm and pulse duration of 20 ns and with Nd-glass laser pulses converted to the third harmonic wavelength of 355 nm with duration of 0.6 ns. Measurements are presented for transparent window materials, crystals and harmonic generation, single layer dielectric films of oxide and fluoride materials and multilayer high reflectivity and antireflective coatings

In Vitro Comparison Of Fluoride Gel Alone and in Combination With Er,Cr:YSGG Laser on Reducing White Spot Lesions in Primary Teeth.

Science.gov (United States)

Molaasadollah, Fatemeh; Asnaashari, Mohammad; Mashhadi Abbas, Fatemeh; Jafary, Maral

2017-01-01

Introduction: Laser therapy has been suggested as a method for caries-prevention, and ErCr:YSGG laser is increasingly used in dentistry. This study aimed to compare the efficacy of fluoride gel alone and in conjunction with Er,Cr:YSGG laser for remineralization of white spot lesions (WSLs) in primary teeth. Methods: This study was conducted on 20 primary teeth with WSLs extracted for orthodontic reasons. Three sections were made of each tooth at the site of WSLs. The surface area of WSLs was measured under a stereomicroscope at ×25 magnification. Samples were assigned to 3 groups of control (group 1), exposure to 1.23% APF gel for 4 minutes (group 2) and Er,Cr:YSGG laser (0.5 W power, 20 Hz frequency, 60% water, 40% air, pulse duration of 5±1 seconds) plus fluoride (group 3). All samples were stored in artificial saliva for 10 days and then the surface area of the WSLs was measured again under a stereomicroscope. Data were analyzed using the Kruskal-Wallis, MannWhitney and Wilcoxon signed rank tests. Results: The reduction in surface area of the WSLs was significantly different between the control and fluoride ( P laser plus fluoride groups ( P laser plus fluoride groups was not significant ( P =0.265). Comparison of the surface area of WSLs before and after the intervention showed no significant difference in group one ( P =0.737) while this difference in groups 2 ( P laser irradiation plus 1.23% APF gel was not significantly different from the application of fluoride gel alone in enhancing the remineralization of WSLs.

Krypton laser treatment of　neovascularization in retinal vein occlusion%氪激光治疗视网膜静脉阻塞的新生血管

Institute of Scientific and Technical Information of China (English)

吴又凯; 武志峰; 张清

2001-01-01

Objective　To investigate the method and effect of krypton laser photocoagulation for neovascularization in retinal vein occlusion.　Methods　Tweenty eight eyes of 27 patients with retinal vein occlusion with neovascularization were photocoagulated by krypton-green and-red laser.The fundus changes were observed by fundus fluorescein angiography after photocoagulation.　Results　The neovascularization disappeared completely in 20 eyes and became smaller in 6 eyes,remained no-change in 2 eyes,and the visual acuity improved in 17 eyes (60.7%) after 6 monthes to 2.5 years of follow-up.　Conclusion　Krypton laser photocoagulation is obviously effective on regression of neovascularization and prevenion of vitreous hemorrhage in retinal vein occlusion.%目的探讨氪激光治疗视网膜静脉阻塞新生血管的方法和疗效。方法对27例视网膜静脉阻塞伴有新生血管的28只患眼采用氪绿、氪红激光进行光凝治疗。光凝后经6个月～2．5年随访，对比分析光凝前后的荧光素眼底血管造影及视力变化情况。结果新生血管萎缩20只眼，占71．4％，好转6只眼，占21．4%，无效2只眼，占7．2%。视力进步17只眼，占60．7%。结论氪激光光凝术对视网膜静脉阻塞新生血管的消退及预防其玻璃体积血具有显著疗效。

Solid sources of krypton-85

International Nuclear Information System (INIS)

Puig, J.R.; Sandier, J.

1962-01-01

Krypton-85, a β-emitter with a long half-life and low biological hazard, has considerable industrial potentialities. It is difficult, however, to manufacture sources since the element occurs in gaseous form and cannot be chemically fixed. The authors describe a method of krypton-fixation in a macromolecular matrix formed by mass polymerization of a liquid monomer containing krypton; they also give an account of the preparation of two types of source produced in this way-one enclosed in polystyrene, the other in polyvinyl acetate. Such sources lose krypton; the activity of the first decreases by 8 % daily, that of the second by 3 % daily. These apparent decays enable the diffusion coefficients of krypton in these polymers to be calculated. Diffusion appears to be prevented by the cross-linkages which exist in the polymers. (author) [fr

The Nike Laser Facility and its Capabilities

Science.gov (United States)

Serlin, V.; Aglitskiy, Y.; Chan, L. Y.; Karasik, M.; Kehne, D. M.; Oh, J.; Obenschain, S. P.; Weaver, J. L.

2013-10-01

The Nike laser is a 56-beam krypton fluoride (KrF) system that provides 3 to 4 kJ of laser energy on target. The laser uses induced spatial incoherence to achieve highly uniform focal distributions. 44 beams are overlapped onto target with peak intensities up to 1016 W/cm2. The effective time-averaged illumination nonuniformity is Nike produces highly uniform ablation pressures on target allowing well-controlled experiments at pressures up to 20 Mbar. The other 12 laser beams are used to generate diagnostic x-rays radiographing the primary laser-illuminated target. The facility includes a front end that generates the desired temporal and spatial laser profiles, two electron-beam pumped KrF amplifiers, a computer-controlled optical system, and a vacuum target chamber for experiments. Nike is used to study the physics and technology issues of direct-drive laser fusion, such as, hydrodynamic and laser-plasma instabilities, studies of the response of materials to extreme pressures, and generation of X rays from laser-heated targets. Nike features a computer-controlled data acquisition system, high-speed, high-resolution x-ray and visible imaging systems, x-ray and visible spectrometers, and cryogenic target capability. Work supported by DOE/NNSA.

Bandwidth Dependence of Laser Plasma Instabilities Driven by the Nike KrF Laser

Science.gov (United States)

Weaver, J. L.; Oh, J.; Seely, J.; Kehne, D.; Brown, C. M.; Obenschain, S.; Serlin, V.; Schmitt, A. J.; Phillips, L.; Lehmberg, R. H.; McLean, E.; Manka, C.; Feldman, U.

2011-10-01

The Nike krypton-fluoride (KrF) laser at the Naval Research Laboratory operates in the deep UV (248 nm) and employs beam smoothing by induced spatial incoherence (ISI). In the first ISI studies at longer wavelengths (1054 nm and 527 nm) [Obenschain, PRL 62, 768(1989);Mostovych, PRL, 59, 1193(1987); Peyser, Phys. Fluids B 3, 1479(1991)], stimulated Raman scattering, stimulated Brillouin scattering, and the two plasmon decay instability were reduced when wide bandwidth ISI (δν / ν ~ 0.03-0.19%) pulses irradiated targets at moderate to high intensities (1014-1015W/cm2) . Recent Nike work showed that the threshold for quarter critical instabilities increased with the expected wavelength scaling, without accounting for the large bandwidth (δν ~ 1-3 THz). New experiments will compare laser plasma instabilities (LPI) driven by narrower bandwidth pulses to those observed with the standard operation. The bandwidth of KrF lasers can be reduced by adding narrow filters (etalons or gratings) in the initial stages of the laser. This talk will discuss the method used to narrow the output spectrum of Nike, the laser performance for this new operating mode, and target observations of LPI in planar CH targets. Work supported by DoE/NNSA.

Measurements of laser-imprinted perturbations and Rayleigh--Taylor growth with the Nike KrF laser

International Nuclear Information System (INIS)

Pawley, C.J.; Gerber, K.; Lehmberg, R.H.; McLean, E.A.; Mostovych, A.N.; Obenschain, S.P.; Sethian, J.D.; Serlin, V.; Stamper, J.A.; Sullivan, C.A.; Bodner, S.E.; Colombant, D.; Dahlburg, J.P.; Schmitt, A.J.; Gardner, J.H.; Brown, C.; Seely, J.F.; Lehecka, T.; Aglitskiy, Y.; Deniz, A.V.; Chan, Y.; Metzler, N.; Klapisch, M.

1997-01-01

Nike is a 56 beam Krypton Fluoride (KrF) laser system using Induced Spatial Incoherence (ISI) beam smoothing with a measured focal nonuniformity left-angle ΔI/I right-angle of 1% rms in a single beam [S. Obenschain et al., Phys. Plasmas 3, 1996 (2098)]. When 37 of these beams are overlapped on the target, we estimate that the beam nonuniformity is reduced by √(37), to (ΔI/I)congruent 0.15% (excluding short-wavelength beam-to-beam interference). The extraordinary uniformity of the laser drive, along with a newly developed x-ray framing diagnostic, has provided a unique facility for the accurate measurements of Rayleigh--Taylor amplified laser-imprinted mass perturbations under conditions relevant to direct-drive laser fusion. Data from targets with smooth surfaces as well as those with impressed sine wave perturbations agree with our two-dimensional (2-D) radiation hydrodynamics code that includes the time-dependent ISI beam modulations. A 2-D simulation of a target with a 100 Angstrom rms randomly rough surface finish driven by a completely uniform beam gives final perturbation amplitudes similar to the experimental data for the smoothest laser profile. These results are promising for direct-drive laser fusion

Krypton K-shell X-ray spectra recorded by the HENEX spectrometer

Energy Technology Data Exchange (ETDEWEB)

Seely, J.F. [Naval Research Laboratory, Space Science Division, Washington DC 20375 (United States)]. E-mail: john.seely@nrl.navy.mil; Back, C.A. [Lawrence Livermore National Laboratory, Livermore CA 94550 (United States); Constantin, C. [Lawrence Livermore National Laboratory, Livermore CA 94550 (United States); Lee, R.W. [Lawrence Livermore National Laboratory, Livermore CA 94550 (United States); Chung, H.-K. [Lawrence Livermore National Laboratory, Livermore CA 94550 (United States); Hudson, L.T. [National Institute of Standards and Technology, Gaithersburg MD 20899 (United States); Szabo, C.I. [National Institute of Standards and Technology, Gaithersburg MD 20899 (United States); Henins, A. [National Institute of Standards and Technology, Gaithersburg MD 20899 (United States); Holland, G.E. [SFA Inc., 9315 Largo Drive West Suite 200, Largo MD 20774 (United States); Atkin, R. [Tiger Innovations, L.L.C., 3610 Vacation Lane, Arlington VA 22207 (United States); Marlin, L. [Naval Research Laboratory, Space Science Division, Washington DC 20375 (United States)

2006-05-15

High-resolution X-ray spectra were recorded by the High-Energy Electronic X-ray (HENEX) spectrometer from a variety of targets irradiated by the Omega laser at the Laboratory for Laser Energetics. The HENEX spectrometer utilizes four reflection crystals covering the 1-20keV energy range and one quartz(10-11) transmission crystal (Laue geometry) covering the 11-40keV range. The time-integrated spectral images were recorded on five CMOS X-ray detectors. In the spectra recorded from krypton-filled gasbag and hohlraum targets, the helium-like K-shell transitions n=1-2, 1-3, and 1-4 appeared in the 13-17keV energy range. A number of additional spectral features were observed at energies lower than the helium-like n=1-3 and n=1-4 transitions. Based on computational simulations of the spectra using the FLYCHK/FLYSPEC codes, which included opacity effects, these additional features are identified to be inner-shell transitions from the Li-like through N-like krypton charge states. The comparisons of the calculated and observed spectra indicate that these transitions are characteristic of the plasma conditions immediately after the laser pulse when the krypton density is 2x10{sup 18}cm{sup -3} and the electron temperature is in the range 2.8-3.2keV. These spectral features represent a new diagnostic for the charge state distribution, the density and electron temperature, and the plasma opacity. Laboratory experiments indicate that it is feasible to record K-shell spectra from gold and higher Z targets in the >60keV energy range using a Ge(220) transmission crystal.

Design documentation: Krypton encapsulation preconceptual design

International Nuclear Information System (INIS)

Knecht, D.A.

1994-10-01

US EPA regulations limit the release of Krypton-85 to the environment from commercial facilities after January 1, 1983. In order to comply with these regulations, Krypton-85, which would be released during reprocessing of commercial nuclear fuel, must be collected and stored. Technology currently exists for separation of krypton from other inert gases, and for its storage as a compressed gas in steel cylinders. The requirements, which would be imposed for 100-year storage of Krypton-85, have led to development of processes for encapsulation of krypton within a stable solid matrix. The objective of this effort was to provide preconceptual engineering designs, technical evaluations, and life cycle costing data for comparison of two alternate candidate processes for encapsulation of Krypton-85. This report has been prepared by The Ralph M. Parsons Company for the US Department of Energy

Design documentation: Krypton encapsulation preconceptual design

Energy Technology Data Exchange (ETDEWEB)

Knecht, D.A. [Idaho National Engineering Lab., Idaho Falls, ID (United States)

1994-10-01

US EPA regulations limit the release of Krypton-85 to the environment from commercial facilities after January 1, 1983. In order to comply with these regulations, Krypton-85, which would be released during reprocessing of commercial nuclear fuel, must be collected and stored. Technology currently exists for separation of krypton from other inert gases, and for its storage as a compressed gas in steel cylinders. The requirements, which would be imposed for 100-year storage of Krypton-85, have led to development of processes for encapsulation of krypton within a stable solid matrix. The objective of this effort was to provide preconceptual engineering designs, technical evaluations, and life cycle costing data for comparison of two alternate candidate processes for encapsulation of Krypton-85. This report has been prepared by The Ralph M. Parsons Company for the US Department of Energy.

Synthesis and characterization of ruthenium fluorides and oxide fluorides with high oxidation states

International Nuclear Information System (INIS)

Meublat, L.

1989-10-01

The synthesis of ruthenium fluorides and oxide fluorides with high oxidation states was attempted from dioxide RuO 2 and tetroxide RuO 4 . Three fluorinating agents were used: fluorine, chlorine trifluoride and krypton difluoride. The reactions were achieved in anhydrous hydrogen fluoride at room temperature. Thus, the reaction of RuO 4 with CIF 3 enabled us to prepare chloryl hexafluororuthenate (V), CIO 2 + RuF 6 - , a new compound well identified by vibrational spectroscopy (infra-red and Raman), the structure of which was determined. The reaction of KrF 2 with RuO 4 gave the oxide tetrafluoride RuOF 4 , the previously published syntheses and properties of which were not in agreement with each other. This compound was definitely characterized here by chemical analysis, infra-red spectroscopy and X-ray powder diffraction. The product of thermal decomposition (70 0 C) of RuOF 4 is presumably RuF 4 since only oxygen is liberated during this decomposition. At last, the reaction of KrF 2 with RuO 2 probably leads to the formation of the new oxide fluoride RuO 2 F 4 . Indeed, no oxygen is given off during this reaction, the chemical analysis of the red-orange coloured solid residue is almost in agreement with the one proposed and its infra-red absorption spectrum indicates the presence of ruthenium-oxygen and ruthenium-terminal and bridging fluorine bonds [fr

Synthesis and characterization of ruthenium fluorides and oxide fluorides with high oxidation states

International Nuclear Information System (INIS)

Meublat, L.

1989-01-01

The synthesis of ruthenium fluorides and oxide fluorides with high oxidation states was attempted from dioxide RuO 2 and tetroxide RuO 4 . Three fluorinating agents were used: fluorine, chlorine trifluoride and krypton difluoride. The reactions were achieved in anhydrous hydrogen fluoride at room temperature. Thus, the reaction of RuO 4 with CIF 3 enabled us to prepare chloryl hexafluororuthenate (V), ClO 2 + RuF 6 - , a new compound well idendified by vibrational spectroscopy (infra-red and Raman), the structure of which was determined. The reaction of KrF 2 with RuO 4 gave the oxide tetrafluoride RuOF 4 , the previously published syntheses and properties of which were not in agreement with each other. This compound was definitely characterized here by chemical analysis, infra-red spectroscopy and X-ray powder diffraction. The product of thermal decomposition (70 0 C) of RuOF 4 is presumably RuF 4 since only oxygen is liberated during this decomposition. At last, the reaction of KrF 2 with RuO 2 probably leads to the formation of the new oxide fluoride RuO 2 F 4 . Indeed, no oxygen is given off during this reaction, the chemical analysis of the red-orange coloured solid residue is almost in agreement with the one proposed and its infra-red absorption spectrum indicates the presence of ruthenium-oxygen and ruthenium-terminal and bridging fluorine bonds [fr

Separation, storage and disposal of krypton-85

International Nuclear Information System (INIS)

1980-01-01

Technical means available for the retention of 85 Kr and its immobilization, storage and disposal are reviewed. Cryogenic processes for the separation of krypton and xenon from diluting gases are discussed in more detail. Besides the cryogenic processes, a liquid adsorption process for reprocessing off-gases and charcoal adsorption and membrane processes for reactor off-gases are also dealt with. The retained krypton can be stored in pressurized containers with air or water cooling. The containers can be kept in engineered storage facilities for an intermediate period or until the 85 Kr has decayed. Alternatively, the krypton may be encapsulated in a solid. The injection of gases containing krypton into suitable geologic strata may also be possible. Much of the equipment required for the separation and storage of krypton, well known from ordinary technology, often needs some adaptation. Further R and D work is, however, needed to solve some problems which are specific to highly concentrated fission krypton. The subject is reviewed under the following headings: methods available for the separation of krypton from off-gases; separation of krypton from reactor off-gas; separation of krypton from reprocessing off-gas; conditioning methods; engineering storage; transportation; disposal

The Nike electron-beam-pumped KrF laser amplifiers

International Nuclear Information System (INIS)

Sethian, J.D.; Pawley, C.J.; Obenschain, S.P.

1997-01-01

Nike is a recently completed multikilojoule krypton-fluoride (KrF) laser that has been built to study the physics of direct-drive inertial confinement fusion. The two final amplifiers of the Nike laser are both electron-beam-pumped systems. This paper describes these two amplifiers, with an emphasis on the pulsed power. The smaller of the two has a 20 x 20 cm aperture, and produces an output laser beam energy in excess of 100 J. This 20 cm Amplifier uses a single 12 kJ Marx generator to inject two 300 kV, 75 kA, 140 ns flat-top electron beams into opposite sides of the laser cell. The larger amplifier in Nike has a 60 x 60 cm aperture, and amplifies the laser beam up to 5 kJ. This 60 cm amplifier has two independent electron beam systems. Each system has a 170 kJ Marx generator that produces a 670 kV, 540 kA, 240 ns flat-top electron beam. Both amplifiers are complete, fully integrated into the laser, meet the Nike system requirements, and are used routinely for laser-target experiments

Time-resolved output spectrum from a hydrogen fluoride laser using mixtures of SF6 and HI

International Nuclear Information System (INIS)

Greiner, N.R.

1975-01-01

The time-resolved spectrum from a transverse-discharge hydrogen fluoride (HF) laser using a mixture of SF 6 and HI is reported. Because this spectrum matches that from a high-pressure H 2 -F 2 laser, and because the SF 6 -HI mixture is chemically stable, this laser should be a suitable and convenient source for probing H 2 -F 2 amplifiers

The development of fluorides for high power laser optics

Science.gov (United States)

Ready, J. F.; Vora, H.

1980-07-01

The laser assisted thermonuclear fusion program has need for improved optical materials with high transmission in the ultraviolet, and with low values of nonlinear index of refraction. Lithium fluoride possesses a combination of optical properties which are of use. Single crystalline LiF is limited by low mechanical strength. The technique of press forging to increase the mechanical strength is investigated. LiF single crystals were press forged over the temperature range 300 - 600 deg C to produce fine grained polycrystalline material. Optical homogenity at 633, stress birefringence, scattering at 633, residual absorption over the spectral range 339 - 3800 nm, and laser damage thresholds for 1 ns, 1064 nm and 700 ps, 266 nm laser pulses are evaluated. Single crystals can be press forged without seriously degrading their optical properties. Yield strength in compression, proportional limit and fracture strength in 3 and 4 point bending, fracture energy, and threshold for microyield are discussed.

LPI Experiments at the Nike Laser*

Science.gov (United States)

Weaver, J.; Oh, J.; Afeyan, B.; Phillips, L.; Seely, J.; Brown, C.; Karasik, M.; Serlin, V.; Obenschain, S.; Chan, L.-Y.; Kehne, D.; Brown, D.; Schmitt, A.; Velikovich, A.; Feldman, U.; Holland, G.; Aglitskiy, Y.

2007-11-01

Advanced implosion designs under development at NRL for direct drive inertial confinement fusion incorporate high intensity pulses from a krypton-fluoride (KrF) laser to achieve significant gain with lower total laser energy (Etot˜500 kJ). These designs will be affected by the thresholds and magnitudes of laser plasma instabilities (LPI). The Nike laser can create short, high intensity pulses (t 10^15 W/cm^2) to explore how LPI will be influenced by the deep UV (248 nm), broad bandwidth (2-3 THz), and induced spatial incoherence beam smoothing of the NRL KrF laser systems. Previous results demonstrated no visible/VUV signatures of two-plasmon decay (2φp) for overlapped intensities ˜2x10^15 W/cm^2. We have increased the laser intensity and expanded the range of targets and diagnostics. Single and double pulse experiments are being planned with solid, foam, and cryogenic targets. In addition to spectrometers to study SRS, 2φp, SBS, and the parametric decay instability, hard x-ray spectrometers (hν>2 keV) and a scintillator/photomultiplier array (hν>10 keV) have been deployed to examine hot electron generation. *Work supported by U. S. DoE.

Krypton oxides under pressure.

Science.gov (United States)

Zaleski-Ejgierd, Patryk; Lata, Pawel M

2016-02-02

Under high pressure, krypton, one of the most inert elements is predicted to become sufficiently reactive to form a new class of krypton compounds; krypton oxides. Using modern ab-initio evolutionary algorithms in combination with Density Functional Theory, we predict the existence of several thermodynamically stable Kr/O species at elevated pressures. In particular, our calculations indicate that at approx. 300 GPa the monoxide, KrO, should form spontaneously and remain thermo- and dynamically stable with respect to constituent elements and higher oxides. The monoxide is predicted to form non-molecular crystals with short Kr-O contacts, typical for genuine chemical bonds.

Long-term storage of recovered krypton

International Nuclear Information System (INIS)

Horii, Yuji; Yamamoto, Yoshimasa

1983-01-01

Various storage methods for krypton-85 recovered from a nuclear fuel reprocessing plant are under development in many countries. These methods include:(1) direct storage in pressurized cylinders, (2) storage of krypton adsorbed on charcoal or zeolite in pressurized cylinders and (3) immobilization (encapsulation) in zeolite. A krypton storage facility using pressurized cylinders has been constructed in the krypton recovery pilot plant in Tokaimura and other methods are now under development. These three methods are evaluated and the features of the constructed facility are also reported. (author)

The accumulation of femtosecond laser radiation energy in crystals of lithium fluoride

Science.gov (United States)

Dresvyanskiy, V. P.; Glazunov, D. S.; Alekseev, S. V.; Losev, V. F.; Chadraa, B.; Bukhtsooj, O.; Baasankhuu, N.; Zandan, B.; Martynovich, E. F.

2015-12-01

We present the results of studies of energy accumulation during the non-destructive interaction of extremely intense near infrared laser radiation with model wide band gap dielectric crystals of lithium fluoride, when the intensity of pulses is sufficient for effective highly nonlinear absorption of light and for the excitation of the electron subsystem of matter and the energy of pulses is still not sufficient for significant heating, evaporation, laser breakdown or other destruction to occur. We studied the emission of energy in the form of light sum of thermally stimulated luminescence accumulated under conditions of self-focusing and multiple filamentation of femtosecond laser radiation. It was established that it's the F2 and F3+ color centers and supplementary to them centers of interstitial type which accumulate energy under the action of a single femtosecond laser pulses. When irradiated by series of pulses the F3, F3- and F4 centers additionally appear. F2 centers are the main centers of emission in the process of thermally stimulated luminescence of accumulated energy. The interstitial fluoride ions (I-centers) are the kinetic particles. They split off from the X3- centers in the result of thermal decomposition of latter on the I-centers and molecules X20. I-centers recombine with F3+ centers and form F2 centers in excited state. The latter produce the characteristic emission spectrum emitted in the form of thermally stimulated luminescence.

Clinical Abservation of Krypton Laser Photocoagulation Preventing Retinal Detachment after LASIK on High Myopia%眼底激光预防中高度近视LASIK术后视网膜脱离的临床观察

Institute of Scientific and Technical Information of China (English)

周建平; 胡莉群; 胡长青

2014-01-01

目的观察LASIK术前对中高度近视患者行预防性眼底激光光凝的疗效。方法准备接受LASIK手术的中高度近视患者作详细眼底检查，直接眼底镜、间接眼底镜和三面镜检查明确有视网膜变性或(和)干性裂孔的患者共61例(112眼)行氪激光光凝治疗。结果61例(112眼)患者氪激光光凝术后变性区及裂孔封闭良好，未发生视网膜脱离。结论对明确有视网膜变性和裂孔的中高度近视患者LASIK术前行氪激光光凝是预防LASIK术后发生孔源性视网膜脱离的一种安全有效的方法。%Objective To observe the effect of krypton laser photocoagulation before LASIK on high myopia. Methods Full fundus examination on high myopic patients was performed with direct ophthalmoscopy, indirect ophthalmoscopy and three mirror contact lens. 112 eyes of 61 patients with peripheral retinal degeneration or retinal hole were treated by krypton laser photocoagulation before LASIK. Results 112 eyes of 61 patients with peripheral retinal degeneration or retinal hole were stable after krypton laser photocoagulation.No retinal detachment was occurred. Conclusion The krypton laser photocoagulation is a safe and ef ective method to preventing retinal detachment for the patients with peripheral retinal degeneration or retinal hole.

Extraction of plutonium from lean residues by room-temperature fluoride volatility

International Nuclear Information System (INIS)

Campbell, G.M.; Foropoulos, J.; Kennedy, R.C.; Dye, B.A.; Behrens, R.G.

1990-01-01

The use of dioxygen difluoride and krypton difluoride for the recovery of plutonium from lean residues by conversion to gaseous plutonium hexa-fluoride is being investigated. The synthesis of dioxygen difluoride in practical quantity has been demonstrated. Fluorination of plutonium compounds under ideal conditions supports the contention that a viable process can be developed. Application of the method to lean plutonium residues is in the early stage of development

Acceleration to high velocities and heating by impact using Nike KrF laser

International Nuclear Information System (INIS)

Karasik, Max; Weaver, J. L.; Velikovich, A. L.; Zalesak, S. T.; Bates, J. W.; Obenschain, S. P.; Schmitt, A. J.; Aglitskiy, Y.; Watari, T.; Arikawa, Y.; Sakaiya, T.; Murakami, M.; Azechi, H.; Oh, J.

2010-01-01

The Nike krypton fluoride laser [S. P. Obenschain, S. E. Bodner, D. Colombant, et al., Phys. Plasmas 3, 2098 (1996)] is used to accelerate planar plastic foils to velocities that for the first time reach 1000 km/s. Collision of the highly accelerated deuterated polystyrene foil with a stationary target produces ∼Gbar shock pressures and results in heating of the foil to thermonuclear temperatures. The impact conditions are diagnosed using DD fusion neutron yield, with ∼10 6 neutrons produced during the collision. Time-of-flight neutron detectors are used to measure the ion temperature upon impact, which reaches 2-3 keV.

Modeling of excimer laser radiation induced defect generation in fluoride phosphate glasses

International Nuclear Information System (INIS)

Natura, U.; Ehrt, D.

2001-01-01

Fluoride phosphate (FP) glasses with low phosphate content are high-transparent in the deep ultraviolet (UV) range and attractive candidates for UV-optics. Their optical properties are complementary to fluoride crystals. The anomalous partial dispersion makes them desirable for optical lens designs to reduce the secondary spectrum. Their UV transmission is limited by trace impurities introduced by raw materials and decreases when exposed to UV-radiation (lamps, lasers). The experiments of the paper published previously in this journal were used in order to separate radiation induced absorption bands in the fluoride phosphate glass FP10. In this paper the generation mechanism of the phosphorus-oxygen related hole center POHC 2 is investigated in detail in glasses of various compositions (various phosphate and impurity contents) in order to predict the transmission loss in case of long-time irradiation. Experiments were carried out using ArF- and KrF-excimer lasers (ns-pulses). POHC 2 generation strongly depends on the phosphate content and on the content of Pb 2+ . A model was developed on these terms. Rate equations are formulated, incorporating the influence of the Pb 2+ -content on the defect generation, a two-step creation term including an energy transfer process and a one-photon bleaching term. This results in a set of coupled nonlinear differential equations. Absorption coefficients and lifetimes of the excited states were calculated as well. Experimental results compared well with the numerical analysis of the theoretical rate equations

The distribution, atmospheric transfer, and assessment of krypton-85; Distribution, transfert atmospherique et bilan du krypton-85

Energy Technology Data Exchange (ETDEWEB)

Pannetier, R [Commissariat a l' Energie Atomique, 92 - Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

1968-06-01

Techniques for sampling and measuring krypton-85 have been developed which allowed to determine its geographical distribution. From its use as a tracer, an evaluation of the air masses which cross over the subtropical fronts has been derived. Besides, the stratospheric character of air pollution by krypton-85 at the level of the antarctic soil has been shown out. Levels of krypton-85 seem to point out to an underestimation of the assessment of nuclear explosion fission energies as adopted by the United Nations Scientific committee on the effects of atomic radiation and emphasize the need to set limits as soon as possible to the amounts of krypton-85 released to the atmosphere by fuel-reprocessing plants. (author) [French] La mise au point de techniques de prelevement et de mesure du krypton-85 atmospherique a permis de determiner sa repartition geographique. De son utilisation comme traceur on deduit une evaluation des masses d'air qui traversent les fronts subtropicaux. Par ailleurs, le caractere stratospherique de la pollution de l'air par le krypton-85 au niveau du sol antarctique est mis en evidence. Le bilan du krypton-85 semble reveler une sous-estimation du bilan des energies de fission des explosions adopte par le Comite scientifique des Nations Unies et souligne la necessite de limiter des que possible les quantites de krypton-85 rejetees dans l'atmosphere par les usines de traitement de combustibles irradies. (auteur)

Capture and immobilization of krypton-85

International Nuclear Information System (INIS)

Whitmell, D.S.; Geens, L.; Penzhorn, R.D.; Smith, M.J.S.

1985-01-01

It may become necessary to contain the krypton-85 released from nuclear fuel during reprocessing in order to reduce the exposure to the local population and the radioactive background throughout the world. A brief description is given of studies being carried out in the Indirect Action Programme. The separation of krypton from other off-gases by cryogenic distillation in the presence of oxygen is being studied at SCK/CEN Mol, together with the behavior of ozone in the distillation column. Two processes for the immobilization of krypton in solid forms have been successfully developed and demonstrated. At KfK Karlsruhe, krypton is encapsulated in vitrified zeolites; at AERE Harwell, krypton is immobilized within a metallic matrix. These processes offer excellent gas retention and either could be adopted for a reprocessing plant

Ultra-Trace Analysis of Krypton-85

International Nuclear Information System (INIS)

Daerr, H.; Kalinowski, M.; Kohler, M.; Sahling, P.

2010-01-01

To strengthen the efficiency and effectiveness of nuclear safeguards for detecting undeclared nuclear material and activities we propose to use the radioactive krypton isotope Krypton-85 as a tracer for clandestine plutonium production. The main idea is to detect inexplicable atmospheric Kr85 concentration using the novel technology atom trap trace analysis (ATTA) in order to detect an undeclared reprocessing facility. The Additional Protocol (INFCIRC/540, 1997) establishes the possibility to take environmental samples. Krypton-85 has a combination of unique features which makes it an ideal tracer for plutonium separation activities anywhere in the world. It is always generated along with plutonium and 99.9% remains within the fuel cladding. Due to its half-life of 10.76 years, significant amounts of krypton-85 still remain in the spent fuel even after long cooling times. Krypton is not removed from the atmosphere by any processes like chemical reactions or wash-out. Furthermore, there are no other relevant sources of krypton-85 besides of reprocessing. The novel technology of atom trap trace analysis (ATTA) has been demonstrated by the physics group at Argonne National Laboratory in 1999. This is an ultra-sensitive trace analysis technique able to detect single krypton atoms. We are setting up an ATTA apparatus in our laboratory, which is designed to fulfill all requirements to detect clandestine plutonium production. Our goal is to determine Krypton-85 concentration of one liter samples of atmospheric air with an analysis time of 3 hours. This sample volume reduction is a significant step, since one liter can be taken as a grab sample by sucking it directly into pre-evacuated bottles at atmospheric pressure. The small samples size and the short analysis time of ATTA will make it possible to use krypton-85 as a tracer for clandestine plutonium production with routine operation. (author)

Atomic structure investigation of ionized krypton

International Nuclear Information System (INIS)

Kotze, P.B.

1981-12-01

The experimental lifetimes of ionized Krypton are discussed. Theoretical, the Coulomb approximation proves to be a reliable tool for the performance of calculations in Krypton II, where in general good agreement between experimental and theoretical lifetimes is reached, but its vulnerability is exposed in the case of Krypton III, where only results concerning levels with a 4p 3 ( 4 S 0 ) parent core can be obtained. Although the single configuration Hartree-Fock approximation turns out to be an adequate way of obtaining wave functions of excited states in Krypton III, cancellation effects resulting from configuration-interaction mixing, make the calculated transition probabilities in Krypton II less reliable. Previous work on configuration-interaction effects in the spectrum of Krypton II (El 76a, El 76b) reveals that good agreement between experimental and theoretical results can be obtained. A systematic theoretical analysis based on the multi-configurarion Hartree-Fock approximation to account for configuration-interaction effects should contribute a great deal to the existing knowledge of the energy spectra of ionized atoms

The dielectronic satellites to the 2s-3p Ne-like krypton resonance lines

International Nuclear Information System (INIS)

Khakhalin, S.Ya.; Dyakin, V.M.; Faenov, A.Ya.; Fiedorowicz, H.; Bartnik, A.; Parys, P.; Nilsen, J.; Osterheld, A.

1994-01-01

We present an analysis of dielectronic satellite spectra of 2p 6 -2s2p 6 3p Ne-like krypton resonance lines. The satellite structure was registered with high (better than λ/Δλ > 3500) spectral resolution in the emission of a laser irradiated gas puff target. We perform an unambiguous identification of satellite lines caused by radiative transitions from autoionizing states of sodium-like krypton ions. A total of about 20 spectral features are identified, most of them for the first time. Very good agreement between the satellite structure calculations and experimental emission spectra is obtained. (orig.)

The dielectronic satellites to the 2s-3p Ne-like krypton resonance lines

Energy Technology Data Exchange (ETDEWEB)

Khakhalin, S.Ya. (MISDC, NPO ' ' VNIIFTRI' ' , Mendeleevo (Russian Federation)); Dyakin, V.M. (MISDC, NPO ' ' VNIIFTRI' ' , Mendeleevo (Russian Federation)); Faenov, A.Ya. (MISDC, NPO ' ' VNIIFTRI' ' , Mendeleevo (Russian Federation)); Fiedorowicz, H. (Inst. of Optoelectronics, Warsaw (Poland)); Bartnik, A. (Inst. of Optoelectronics, Warsaw (Poland)); Parys, P. (Inst. of Plasma Physics and Laser Microfusion, Warsaw (Poland)); Nilsen, J. (Lawrence Livermore National Lab., Livermore, CA (United States)); Osterheld, A. (Lawrence Livermore National Lab., Livermore, CA (United States))

1994-08-01

We present an analysis of dielectronic satellite spectra of 2p[sup 6]-2s2p[sup 6]3p Ne-like krypton resonance lines. The satellite structure was registered with high (better than [lambda]/[Delta][lambda] > 3500) spectral resolution in the emission of a laser irradiated gas puff target. We perform an unambiguous identification of satellite lines caused by radiative transitions from autoionizing states of sodium-like krypton ions. A total of about 20 spectral features are identified, most of them for the first time. Very good agreement between the satellite structure calculations and experimental emission spectra is obtained. (orig.).

High gain direct drive target designs and supporting experiments with KrF

International Nuclear Information System (INIS)

Karasik, Max; Bates, Jason W.; Aglitskiy, Yefim

2013-01-01

Krypton-fluoride laser is an attractive inertial fusion energy driver from the standpoint of target physics. Target designs taking advantage of zooming, shock ignition, and favorable physics with KrF reach energy gains of 200 with sub-MJ laser energy. The designs are robust under 2D simulations. Experiments on the Nike KrF laser support the physics basis. (author)

Fusion energy research with lasers, direct drive targets, and dry wall chambers

International Nuclear Information System (INIS)

Sethian, J.D.; Obenschain, S.P.; Myers, M.

2003-01-01

We are carrying out a coordinated, focused effort to develop Laser Inertial Fusion Energy. The key components are developed in concert with one another and the science and engineering issues are addressed concurrently. Significant progress has been made in this program: We are evaluating target designs that show it could be possible to achieve the high gains (>100) needed for a practical fusion system. These have a low density CH foam that is wicked with solid DT, and over coated with a thin high-Z layer. Significant advances have been made with the two types of laser are being developed: Krypton Fluoride (KrF) gas lasers and Diode Pumped Solid State Lasers (DPPSL). Both have the potential to meet the fusion energy requirements for rep-rate, efficiency, durability and cost. This paper also presents the advances in development of chamber operating windows (target survival plus no wall erosion), final optics (aluminum at grazing incidence has high reflectivity and exceeds required laser damage threshold), target fabrication (advanced foams and high Z overcoats), and target injection (new facility for target injection and tracking studies). (author)

Laser triggering of a 500-kV gas-filled switch: A parametric study

International Nuclear Information System (INIS)

Woodworth, J.R.; Hargis, P.J. Jr.; Pitchford, L.C.; Hamil, R.A.

1984-01-01

We have investigated neodymium: yttrium aluminum garnet (Nd:YAG) laser triggering of a 500-kV, SF 6 -insulated gas switch for a range of laser parameters. Laser wavelengths of 266 nm and 1064 nm with nominal pulse lengths of 2- and 4-nsec full width at half maximum (FWHM) were used to trigger the switch. The switch was triggered by focusing the laser to form a breakdown arc in the gas between the electrodes. Subnanosecond jitter in the operation of the switch was obtained for 266-nm laser pulse energies as low as 5 mJ. Results obtained with the Nd:YAG laser are compared to earlier data in which the switch was triggered with a krypton-fluoride laser operating at 248 nm with a pulse length of 20-nsec FWHM. Our experimental results show that ultraviolet laser triggering gives results which are a dramatic improvement over infrared laser triggering in terms of lower jitter and smaller change in delay time with variations in applied voltage. We also see indications that the optimum laser pulse length is equal to or greater than the closure time of the switch

Measurements of Laser Plasma Instability (LPI) and Electron Density/Temperature Profiles in Plasmas Produced by the Nike KrF Laser

Science.gov (United States)

Oh, Jaechul; Weaver, J. L.; Serlin, V.; Obenschain, S. P.

2016-10-01

We will present results of simultaneous measurements of LPI-driven light scattering and density/temperature profiles in CH plasmas produced by the Nike krypton fluoride laser (λ = 248 nm). The primary diagnostics for the LPI measurement are time-resolved spectrometers with absolute intensity calibration in spectral ranges relevant to the optical detection of stimulated Raman scattering or two plasmon decay. The spectrometers are capable of monitoring signal intensity relative to thermal background radiation from plasma providing a useful way to analyze LPI initiation. For further understanding of LPI processes, the recently implemented grid image refractometer (Nike-GIR)a is used to measure the coronal plasma profiles. In this experiment, Nike-GIR is equipped with a 5th harmonic probe laser (λ = 213 nm) in attempt to probe into a high density region over the previous peak density with λ = 263 nm probe light ( 4 ×1021 cm-3). The LPI behaviors will be discussed with the measured data sets. Work supported by DoE/NNSA.

Measurements of electron density and temperature profiles in plasma produced by Nike KrF laser for laser plasma instability research

Science.gov (United States)

Oh, Jaechul; Weaver, J. L.; Karasik, M.; Chan, L. Y.

2015-08-01

A grid image refractometer (GIR) has been implemented at the Nike krypton fluoride laser facility of the Naval Research Laboratory. This instrument simultaneously measures propagation angles and transmissions of UV probe rays (λ = 263 nm, Δt = 10 ps) refracted through plasma. We report results of the first Nike-GIR measurement on a CH plasma produced by the Nike laser pulse (˜1 ns FWHM) with the intensity of 1.1 × 1015 W/cm2. The measured angles and transmissions were processed to construct spatial profiles of electron density (ne) and temperature (Te) in the underdense coronal region of the plasma. Using an inversion algorithm developed for the strongly refracted rays, the deployed GIR system probed electron densities up to 4 × 1021 cm-3 with the density scale length of 120 μm along the plasma symmetry axis. The resulting ne and Te profiles are verified to be self-consistent with the measured quantities of the refracted probe light.

Towards diode-pumped mid-infrared praseodymium-ytterbium-doped fluoride fiber lasers

Science.gov (United States)

Woodward, R. I.; Hudson, D. D.; Jackson, S. D.

2018-02-01

We explore the potential of a new mid-infrared laser transition in praseodymium-doped fluoride fiber for emission around 3.4 μm, which can be conveniently pumped by 0.975 μm diodes via ytterbium sensitizer co-doping. Optimal cavity designs are determined through spectroscopic measurements and numerical modeling, suggesting that practical diode-pumped watt-level mid-infrared fiber sources beyond 3 μm could be achieved.

Process and device for the adsorptive separation of krypton from a krypton/nitrogen gas mixture

International Nuclear Information System (INIS)

Ringel, H.; Messler, M.

1985-01-01

The gas mixture flows through an adsorption column, which is filled with a means of adsorbing Krypton and nitrogen. The adsorption column is desorbed after adsorption of the gas components by a gaseous flushing material, which flows through the adsorption column in the same direction as the gas mixture. In order to achieve a high degree of separation, the adsorption material is loaded with nitrogen and Krypton from the gas inlet, where Krypton is only absorbed over part of the length of the whole column by the adsorption material. The part of the length is such that on desorption of the adsorption column with the flushing material at first only nitrogen and later only Krypton is obtained at the outlet of the adsorption column. (Waste gas system of a reprocession plant). (orig./HP) [de

Observation of parametric instabilities in the quarter critical density region driven by the Nike KrF laser

Energy Technology Data Exchange (ETDEWEB)

Weaver, J. L.; Kehne, D.; Brown, C. M.; Obenschain, S. P.; Serlin, V.; Schmitt, A. J. [U.S. Naval Research Laboratory, Washington DC 20375 (United States); Oh, J.; Lehmberg, R. H.; Mclean, E.; Manka, C. [Research Support Instruments, Lanham, Maryland 20905 (United States); Phillips, L. [Alogus Research Corporation, McLean, Virginia 22101 (United States); Afeyan, B. [Polymath Research, Inc., Pleasanton, California 94566 (United States); Seely, J.; Feldman, U. [Berkeley Research Associates, Inc., Beltsville, Maryland 20705 (United States)

2013-02-15

The krypton-fluoride (KrF) laser is an attractive choice for inertial confinement fusion due to its combination of short wavelength ({lambda}=248 nm), large bandwidth (up to 3 THz), and superior beam smoothing by induced spatial incoherence. These qualities improve the overall hydrodynamics of directly driven pellet implosions and should allow use of increased laser intensity due to higher thresholds for laser plasma instabilities when compared to frequency tripled Nd:glass lasers ({lambda}=351 nm). Here, we report the first observations of the two-plasmon decay instability using a KrF laser. The experiments utilized the Nike laser facility to irradiate solid plastic planar targets over a range of pulse lengths (0.35 ns{<=}{tau}{<=}1.25 ns) and intensities (up to 2 Multiplication-Sign 10{sup 15} W/cm{sup 2}). Variation of the laser pulse created different combinations of electron temperature and electron density scale length. The observed onset of instability growth was consistent with the expected scaling that KrF lasers have a higher intensity threshold for instabilities in the quarter critical density region.

Observation of parametric instabilities in the quarter critical density region driven by the Nike KrF laser

International Nuclear Information System (INIS)

Weaver, J. L.; Kehne, D.; Brown, C. M.; Obenschain, S. P.; Serlin, V.; Schmitt, A. J.; Oh, J.; Lehmberg, R. H.; Mclean, E.; Manka, C.; Phillips, L.; Afeyan, B.; Seely, J.; Feldman, U.

2013-01-01

The krypton-fluoride (KrF) laser is an attractive choice for inertial confinement fusion due to its combination of short wavelength (λ=248 nm), large bandwidth (up to 3 THz), and superior beam smoothing by induced spatial incoherence. These qualities improve the overall hydrodynamics of directly driven pellet implosions and should allow use of increased laser intensity due to higher thresholds for laser plasma instabilities when compared to frequency tripled Nd:glass lasers (λ=351 nm). Here, we report the first observations of the two-plasmon decay instability using a KrF laser. The experiments utilized the Nike laser facility to irradiate solid plastic planar targets over a range of pulse lengths (0.35 ns≤τ≤1.25 ns) and intensities (up to 2×10 15 W/cm 2 ). Variation of the laser pulse created different combinations of electron temperature and electron density scale length. The observed onset of instability growth was consistent with the expected scaling that KrF lasers have a higher intensity threshold for instabilities in the quarter critical density region.

Observation of parametric instabilities in the quarter critical density region driven by the Nike KrF laser

Science.gov (United States)

Weaver, J. L.; Oh, J.; Phillips, L.; Afeyan, B.; Seely, J.; Kehne, D.; Brown, C. M.; Obenschain, S. P.; Serlin, V.; Schmitt, A. J.; Feldman, U.; Lehmberg, R. H.; Mclean, E.; Manka, C.

2013-02-01

The krypton-fluoride (KrF) laser is an attractive choice for inertial confinement fusion due to its combination of short wavelength (λ =248 nm), large bandwidth (up to 3 THz), and superior beam smoothing by induced spatial incoherence. These qualities improve the overall hydrodynamics of directly driven pellet implosions and should allow use of increased laser intensity due to higher thresholds for laser plasma instabilities when compared to frequency tripled Nd:glass lasers (λ =351 nm). Here, we report the first observations of the two-plasmon decay instability using a KrF laser. The experiments utilized the Nike laser facility to irradiate solid plastic planar targets over a range of pulse lengths (0.35 ns≤τ≤1.25 ns) and intensities (up to 2×1015 W/cm2). Variation of the laser pulse created different combinations of electron temperature and electron density scale length. The observed onset of instability growth was consistent with the expected scaling that KrF lasers have a higher intensity threshold for instabilities in the quarter critical density region.

Broadband Optical Active Waveguides Written by Femtosecond Laser Pulses in Lithium Fluoride

International Nuclear Information System (INIS)

Chiamenti, Ismael; Costa, Larissa N. da; Kalinowski, Hypolito J.; Bonfigli, Francesca; Montereali, Rosa Maria; Gomes Anderson, S. L.

2014-01-01

Broadband waveguiding through light-emitting strips directly written in a blank lithium fluoride crystal with a femtosecond laser is reported. Light guiding was observed at several optical wavelengths, from blue, 458 nm, to near-infrared, at 1550 nm. Visible photoluminescence spectra of the optically active F 2 and F 3 + color centers produced by the fs laser writing process were measured. The wavelength-dependent refractive index increase was estimated to be in the order of 10 −3 −10 −4 in the visible and near-infrared spectral intervals, which is consistent with the stable formation of point defects in LiF

Broadband Optical Active Waveguides Written by Femtosecond Laser Pulses in Lithium Fluoride

Science.gov (United States)

Ismael, Chiamenti; Francesca, Bonfigli; Anderson, S. L. Gomes; Rosa, Maria Montereali; Larissa, N. da Costa; Hypolito, J. Kalinowski

2014-01-01

Broadband waveguiding through light-emitting strips directly written in a blank lithium fluoride crystal with a femtosecond laser is reported. Light guiding was observed at several optical wavelengths, from blue, 458 nm, to near-infrared, at 1550 nm. Visible photoluminescence spectra of the optically active F2 and F3+ color centers produced by the fs laser writing process were measured. The wavelength-dependent refractive index increase was estimated to be in the order of 10-3-10-4 in the visible and near-infrared spectral intervals, which is consistent with the stable formation of point defects in LiF.

In vitro study of demineralization resistance and fluoride retention in dental enamel irradiated with Er,Cr: YSGG laser; Estudo in vitro da resistencia a desmineralizacao e da retencao de fluor em esmalte dental irradiado com laser de Er, Cr: YSGG

Energy Technology Data Exchange (ETDEWEB)

Ana, Patricia Aparecida da. E-mail: patriciadaana@yahoo.com.br

2007-07-01

This study aimed to establish irradiation conditions of Er,Cr:YSGG laser ({lambda} of 2.79 {mu}m) which could propitiate changes on human dental enamel and increase its resistance to demineralization, when associated or not with topical application of acidulated phosphate fluoride (APF). Fluences of 2,8 J/cm{sup 2}, 5,6 J/cm{sup 2} e 8,5 J/cm{sup 2} were selected; they were associated or not with previous application of a photo absorber (coal paste) and then APF was applied or not after laser irradiation. In a first step, the morphological findings, the surface temperatures, and the pupal temperatures were evaluated during laser irradiation. After that, the treated samples were submitted to a a ten-day pH-cycling model. After producing the incipient white-spots lesions, the following aspects were evaluated: the mineral loss, the loosely bound fluoride and the firmly bound fluoride. All the demineralizing and remineralizing pH-cycling solutions were evaluated with respect to their calcium (Ca), inorganic phosphorous (Pi) and fluoride (F{sup -}) concentrations. The data had their normality and homogeneity distribution statistically evaluated, and it was chosen an appropriated statistical test for each performed analysis according to the obtained results, considering 5% significant level. The fluences selected for this study created ablated surfaces; the fluences of 5.6 J/cm{sup 2} and 8.5 J/cm{sup 2} promoted increments in surface temperature above 110 deg C. The intrapupal temperature changes revealed that laser irradiation did not increase the pulpal temperatures above the critical threshold for induction of pulpitis. The coal paste did not promote any changes on surface morphology or in the intrapulpal temperature changes; however, this paste increased the surface temperatures during laser irradiation. Only laser irradiation at 8.5 J/cm{sup 2} was able to decrease the mineral loss when compared to the no-treatment group; although the association of coal paste

Method for separating krypton isotopes

International Nuclear Information System (INIS)

Porter, J.T.

1980-01-01

Methods and apparatus for separating krypton isotopes utilizing low temperature selective infrared excitation of 85krypton difluoride in an isotopic compound mixture. Multiphoton ir excitation and uv excitation techniques are used, as well as cryogenic matrix isolation and inert buffer gas isolation techniques

NRL SSD Research Achievements: 19701980. Volume 2

Science.gov (United States)

2015-10-30

many designs. In 1964 proposals by NRL, GSFC, American Science and Engineering, Inc . (AS&E), Harvard College Observatory (HCO), and the High...components were calibrated for projects in collaboration with the NRL Plasma Physics Division Nike laser. This included gratings and spectrometers for...the first accurate measurement of laser-plasma instabilities produced by the krypton-fluoride Nike laser at wavelength 248 nm. Scientists from

Survey of analytical methods for environmental monitoring of krypton-85

International Nuclear Information System (INIS)

Jaquish, R.E.; Moghissi, A.A.

1973-01-01

Numerous methods have been developed for measuring krypton-85 in air as krypton ultimately accumulates in air once it is released into the environment. However, krypton-85 can be present in other media such as natural gas from wells stimulated with nuclear devices or in water when krypton-85 is used for aeration studies. Methods for the measurement of ambient levels of krypton-85 require a concentration of krypton from a large air sample of one m 3 or more. If elevated levels are to be measured, carrier krypton may be used provided the contamination of atmospheric krypton with krypton-85 does not interfere with the measurement. In certain cases, such as in the vicinity of nuclear fuel processing plants, direct measurement techniques may be used. A variety of techniques are employed for krypton-85 counting. At low levels, internal gas counting or organic scintillation is used to measure the beta emission of this radionuclide. At higher levels the gamma emission of krypton-85 may be measured using scintillation or solid state gamma spectroscopic methods. Techniques for collection of the sample, concentration of krypton, and radioactivity measurement of krypton-85 are discussed and various processes are critically evaluated and compared

Preferential site occupancy observed in coexpanded argon-krypton clusters

International Nuclear Information System (INIS)

Lundwall, M.; Bergersen, H.; Lindblad, A.; Oehrwall, G.; Svensson, S.; Bjoerneholm, O.; Tchaplyguine, M.

2006-01-01

Free heterogeneous argon-krypton clusters have been produced by coexpansion and investigated by means of x-ray photoelectron spectroscopy. By examining cluster surface and bulk binding energy shifts, relative intensities, and peak widths, we show that in the mixed argon-krypton clusters the krypton atoms favor the bulk and argon atoms are pushed to the surface. Furthermore, we show that krypton atoms in the surface layer occupy high-coordination sites and that heterogeneous argon-krypton clusters produced by coexpansion show the same surface structure as argon host clusters doped with krypton. These observations are supported by site-dependent calculations of chemical shifts

Quantum cascade laser-based photoacoustic sulfuryl fluoride sensing

Science.gov (United States)

Minini, Kariza Mayra Silva; Bueno, Sâmylla Cristina Espécie; da Silva, Marcelo Gomes; Sthel, Marcelo Silva; Vargas, Helion; Angster, Judit; Miklós, András

2017-02-01

Although sulfuryl fluoride (SO2F2) is an efficient fumigant that does not react with the surface of indoor materials and does not reduce the stratospheric ozone shield, there are some concerns about its use. It is a toxic gas that attacks the central nervous system, and its global warming potential (GWP) value is 4780 for 100 years' time. Therefore, it is a clear necessity of implementing detection methods for tracing such a molecule. In this work a sensitive photoacoustic setup was built to detect SO2F2 at concentrations of parts per billion by volume (ppbv). The symmetric S-O stretching mode was excited by a continuous-wave quantum cascade laser with radiation wavenumber ranging from 1275.7 to 1269.3 cm-1. The photoacoustic signal was generated by modulating the laser wavenumber at the first longitudinal mode of the photoacoustic cell with amplitude depth of 5 × 10-3 cm-1. The detection of a minimum SO2F2 concentration of 20 ppbv was achieved.

Desorption/ablation of lithium fluoride induced by extreme ultraviolet laser radiation

Czech Academy of Sciences Publication Activity Database

Blejchař, T.; Nevrlý, V.; Vašinek, M.; Dostál, M.; Kozubková, M.; Dlabka, J.; Stachoň, M.; Juha, Libor; Bitala, P.; Zelinger, Zdeněk; Pira, Peter; Wild, J.

2016-01-01

Roč. 61, č. 2 (2016), s. 131-138 ISSN 0029-5922. [PLASMA 2015 : International Conference on Research and Applications of Plasmas. Warsaw, 07.09.2015-11.09.2015] R&D Projects: GA ČR(CZ) GAP108/11/1312 Institutional support: RVO:68378271 ; RVO:61388955 Keywords : desorption * fluid dynamics * lithium fluoride * numerical simulation * plume expansion * pulsed laser ablation Subject RIV: BL - Plasma and Gas Discharge Physics; CF - Physical ; Theoretical Chemistry (UFCH-W) Impact factor: 0.760, year: 2016

Spectroscopic properties and quenching processes of Yb3+ in Fluoride single crystals for laser applications

International Nuclear Information System (INIS)

Bensalah, A.; Ito, M.; Guyot, Y.; Goutaudier, C.; Jouini, A.; Brenier, A.; Sato, H.; Fukuda, T.; Boulon, G.

2007-01-01

Spectroscopic characterization is carried out to identify Stark's levels of Yb 3+ transitions in several fluoride crystals grown either by the Czochralski technique or by the laser-heated pedestal growth method. Yb 3+ concentration dependence of the decay time is analyzed in order to understand involved concentration quenching mechanisms. Laser tests under saphire:Ti pumping are presented for all our materials as well as under diode pumping for Yb:CaF 2

Implementation of focal zooming on the Nike KrF laser

Energy Technology Data Exchange (ETDEWEB)

Kehne, D. M.; Karasik, M.; Weaver, J. L.; Chan, Y.; Obenschain, S. P. [Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375 (United States); Aglitsky, Y. [Science Applications International, McLean, Virginia 22150 (United States); Smyth, Z.; Lehmberg, R. H. [Research Support Instruments, Inc., Lanham, Maryland 20706 (United States); Terrell, S. [Commonwealth Technologies, Inc., Alexandria, Virginia 22315 (United States)

2013-01-15

In direct drive inertial confinement laser fusion, a pellet containing D-T fuel is imploded by ablation arising from absorption of laser energy at its outer surface. For optimal coupling, the focal spot of the laser would continuously decrease to match the reduction in the pellet's diameter, thereby minimizing wasted energy. A krypton-fluoride laser ({lambda}= 248 nm) that incorporates beam smoothing by induced spatial incoherence has the ability to produce a high quality focal profile whose diameter varies with time, a property known as focal zooming. A two-stage focal zoom has been demonstrated on the Nike laser at the Naval Research Laboratory. In the experiment, a 4.4 ns laser pulse was created in which the on-target focal spot diameter was 1.3 mm (full width at half maximum) for the first 2.4 ns and 0.28 mm for the final 2 ns. These two diameters appear in time-integrated focal plane equivalent images taken at several locations in the amplification chain. Eight of the zoomed output beams were overlapped on a 60 {mu}m thick planar polystyrene target. Time resolved images of self-emission from the rear of the target show the separate shocks launched by the two corresponding laser focal diameters.

Implementation of focal zooming on the Nike KrF laser

International Nuclear Information System (INIS)

Kehne, D. M.; Karasik, M.; Weaver, J. L.; Chan, Y.; Obenschain, S. P.; Aglitsky, Y.; Smyth, Z.; Lehmberg, R. H.; Terrell, S.

2013-01-01

In direct drive inertial confinement laser fusion, a pellet containing D-T fuel is imploded by ablation arising from absorption of laser energy at its outer surface. For optimal coupling, the focal spot of the laser would continuously decrease to match the reduction in the pellet's diameter, thereby minimizing wasted energy. A krypton-fluoride laser (λ= 248 nm) that incorporates beam smoothing by induced spatial incoherence has the ability to produce a high quality focal profile whose diameter varies with time, a property known as focal zooming. A two-stage focal zoom has been demonstrated on the Nike laser at the Naval Research Laboratory. In the experiment, a 4.4 ns laser pulse was created in which the on-target focal spot diameter was 1.3 mm (full width at half maximum) for the first 2.4 ns and 0.28 mm for the final 2 ns. These two diameters appear in time-integrated focal plane equivalent images taken at several locations in the amplification chain. Eight of the zoomed output beams were overlapped on a 60 μm thick planar polystyrene target. Time resolved images of self-emission from the rear of the target show the separate shocks launched by the two corresponding laser focal diameters.

Implementation of focal zooming on the Nike KrF laser

Science.gov (United States)

Kehne, D. M.; Karasik, M.; Aglitsky, Y.; Smyth, Z.; Terrell, S.; Weaver, J. L.; Chan, Y.; Lehmberg, R. H.; Obenschain, S. P.

2013-01-01

In direct drive inertial confinement laser fusion, a pellet containing D-T fuel is imploded by ablation arising from absorption of laser energy at its outer surface. For optimal coupling, the focal spot of the laser would continuously decrease to match the reduction in the pellet's diameter, thereby minimizing wasted energy. A krypton-fluoride laser (λ = 248 nm) that incorporates beam smoothing by induced spatial incoherence has the ability to produce a high quality focal profile whose diameter varies with time, a property known as focal zooming. A two-stage focal zoom has been demonstrated on the Nike laser at the Naval Research Laboratory. In the experiment, a 4.4 ns laser pulse was created in which the on-target focal spot diameter was 1.3 mm (full width at half maximum) for the first 2.4 ns and 0.28 mm for the final 2 ns. These two diameters appear in time-integrated focal plane equivalent images taken at several locations in the amplification chain. Eight of the zoomed output beams were overlapped on a 60 μm thick planar polystyrene target. Time resolved images of self-emission from the rear of the target show the separate shocks launched by the two corresponding laser focal diameters.

Spectral and far-field broadening due to stimulated rotational Raman scattering driven by the Nike krypton fluoride laser.

Science.gov (United States)

Weaver, James; Lehmberg, Robert; Obenschain, Stephen; Kehne, David; Wolford, Matthew

2017-11-01

Stimulated rotational Raman scattering (SRRS) in the ultraviolet region (λ=248  nm) has been observed at the Nike laser over extended propagation paths in air during high power operation. Although this phenomenon is not significant for standard operating configurations at Nike, broadening of the laser spectrum and far-field focal profiles has been observed once the intensity-path length product exceeds a threshold of approximately 1  TW/cm. This paper presents experimental results and a new theoretical evaluation of these effects. The observations suggest that significantly broader spectra can be achieved with modest degradation of the final focal distribution. These results point to a possible path for enhanced laser-target coupling with the reduction of laser-plasma instabilities due to broad laser bandwidth produced by the SRRS.

The effect of CO2 laser irradiation plus fluoride dentifrice on the inhibition of secondary caries on root surfaces adjacent to glass ionomer cement or composite resin restorations

International Nuclear Information System (INIS)

Rodrigues, S R; Moraes, M; Youssef, M N; De Souza-Zaroni, W C; Hanashiro, F S; Brugnera Junior, A; Nobre-dos-Santos, M

2016-01-01

Although the cariostatic effects of CO 2 laser on the root surface have been shown, there is scarce information regarding its effects on root secondary caries. The objective of this research was to investigate the effect of the association of CO 2 laser and a fluoride dentifrice on the inhibition of secondary caries on root surfaces adjacent to composite-resin or glass-ionomer-cement restorations. Dental blocks of human roots were divided into two groups: composite resin (CR) or glass ionomer cement (GIC). Subsequently, the blocks were divided into four subgroups (n  =  10): C, non-fluoride dentifrice; FD, fluoride dentifrice; L, CO 2 laser with an energy density of 6.0 J cm −2   +  non-fluoride dentifrice; and L  +  FD, CO 2 laser  +  fluoride dentifrice. The blocks were subjected to pH cycling to simulate a high cariogenic challenge. Dental demineralization around the restorations was quantified by microhardness analysis. The results were subjected to analysis of variance (ANOVA) and the Tukey–Kramer test (p  ⩽  0.05). As for mineral loss, it can be observed that all the groups that were treated with a fluoride dentifrice and laser, used alone or not, were statistically similar and superior to the RC–C group. It was concluded that CO 2 laser irradiation and a fluoride dentifrice used alone or combined with each other are efficient surface treatments for preventing secondary root caries, regardless of the restorative material used. (paper)

Krypton retention on solid adsorbents

International Nuclear Information System (INIS)

Monson, P.R. Jr.

1980-01-01

Radioactive krypton-85 is released to the atmosphere in the off-gas from nuclear reprocessing plants. Three main methods have been suggested for removal of krypton from off-gas streams: cryogenic distillation; fluorocarbon absorption; and adsorption on solid sorbents. Use of solid adsorbents is the least developed of these methods, but offers the potential advantages of enhanced safety and lower operating costs. An experimental laboratory program was developed that will be used to investigate systematically many solid adsorbents (such as zeolites, i.e., mordenites) for trapping krypton in air. The objective of this investigation is to find an adsorbent that is more economical than silver-exchanged mordenite. Various physical and chemical characteristics such as adsorption isotherms, decontamination factors, co-adsorption, regeneration, and the mechanism and kinetics of noble gas adsorption were used to characterize the adsorbents. In the experimental program, a gas chromatograph using a helium ionization detector was used to measure the krypton in air before and after the adsorbent bed. This method can determine directly decontamination factors greater than 100

Krypton-85 pollution and atmospheric electricity

International Nuclear Information System (INIS)

Harrison, R.G.; ApSimon, H.M.

1994-01-01

Krypton-86 is a chemically inert radioactive gas present in the atmosphere, concentrations of which have been greatly increased by nuclear reprocessing and weapons testing since 1945. The long half-life (10.7 yr), allows the gas to mix thoroughly in the atmosphere. Ionization caused by krypton-85 increases the electrical conductivity of atmospheric air. Further increases in krypton-85 emissions seem inevitable. The increase in air conductivity due to release of krypton-85 will vary with height, and be larger over the oceans than over the land. Increases in conductivity will produce uncertain effects on atmospheric phenomena, so changes are compared in magnitude with other factors perturbing the conductivity, such as combustion aerosol burdens, volcanic eruptions and nuclear weapons testing. Conductivity changes are expected to have the greatest significance for meteorological phenomena close to the source. (Author)

Nd:YAG laser irradiation on temporary teeth carious tissue using 12% diamine silver fluoride as a photo-absorber - a morphological study

International Nuclear Information System (INIS)

Calmon, Andrea de Avillez

2001-01-01

Since Nd:YAG laser radiation was first introduced in Dentistry various photo-absorbers were employed with the intent of improving its efficacy when used on dental carious tissue. The purpose of the present study was to analyze the influence of this radiation using Scanning and Optical microscopy over carious tissue of primary teeth using two photo-absorbers. 15 primary human teeth were used and, in each one, 3 cavity preparations were performed. Specimens were then submitted to an in vitro demineralizing environment during 18 days. Two of the cavities of each specimen were laser irradiated using the Nd:YAG laser with 60 mJ of energy per pulse, 10 Hz and average power of 0,6 W. The 12% diamine silver fluoride or the mineral coal were used as photo-absorbers. The third cavity of the specimens was used as a control and received no laser irradiation. Samples were transversally cut and the section analyzed by SEM and OM. Results showed that the 12% diamine silver fluoride is an efficient photo-absorber and, when used it the Nd:YAG laser, leading to melting and resolidification of the carious tissue. It can be concluded that the 12% diammine silver fluoride presents advantages over the mineral coal as a photo absorber when used in primary teeth as it promotes and improves the efficacy of laser irradiation. This substance also works as a barrier on the carie progression in deeper areas such as the infected and necrotic zones. (author)

Charge state distribution of ionic kryptons after photoionization

International Nuclear Information System (INIS)

Cai Xiaohong

1992-01-01

Monochromatic X-rays from the 2.3 GeV synchrotron at University Bonn (Germany) are employed for inner shell excitation of krypton. Various ionic kryptons and a number of electrons are produced due to photoionization. In order to study the equilibrium charge state distribution of ionic kryptons, a time of flight mass spectrometer is set up and used to measure the resulting ionic charge spectra with photo energies near the L 1 - , L 2 - and L 3 - absorption edges of krypton. The energy dependence of relative probabilities is presented

The releases of krypton-85 and tritium to the environment and tritium to krypton-85 ratios as source indicators

International Nuclear Information System (INIS)

Schroeder, K.J.P.; Roether, W.

1975-01-01

More than 95% of the krypton-85 that is at present observed in the environment on a global scale originates from the combined releases following nuclear-power generation and plutonium production, while atmospheric fusion-bomb testing accounts for the same percentage of the global tritium. The global inventories at the end of 1973 were 55 MCi (estimated uncertainty +- 10%) of krypton-85, and 2900 MCi (+- 25%) of tritium. From the excess of the global krypton-85 inventory over the amounts accounted for by the sources other than plutonium production, it is concluded that 130 tonnes of plutonium-239 have been produced up to 1970. Pronounced fractionation occurs between atmosphere and hydrosphere, in the sense that the concentration of krypton-85 is lowered, and that of tritium (being overwhelmingly in the form of a water molecule, HTO) is greatly increased, in the hydrosphere. Largely as a consequence of this fractionation, the environmental tritium to krypton-85 ratios cover a wide range, with values lowest in the troposphere (typical order of magnitude 10 -1 Ci/Ci) and highest in continental surface water (of the order of 10 5 ). Preliminary oceanic krypton-85 data are reported, which indicate that the concentration decrease with depth in the ocean is very similar for both nuclides. Effluents from nuclear power reactors and reprocessing plants have tritium to krypton-85 ratios that do not differ markedly from those found at present in the troposphere; on the other hand, the very high ratios that are typical of the hydrosphere may offer opportunities of detecting such effluents in the hydrosphere on the basis of tritium to krypton-85 ratios. Considerable uncertainties in the ratios of the effluents have, however, to be anticipated, arising from varying, and fluctuating, fractionation between the two nuclides in the release processes. (author)

Krypton-85 storage in sputter-deposited amorphous metals

International Nuclear Information System (INIS)

Tingey, G.L.; McClanahan, E.D.; Lytle, J.M.; Gordon, N.R.; Knoll, R.W.

1982-06-01

After comparing options for storing radioactive krypton gas, the United States Department of Energy selected ion implantation of the gas into a sputter-deposited metal matrix as the reference process. This technique is being developed with pilot-scale testing and further characterization of the deposited product. The process involves implanting krypton atoms into a growing deposit during the sputtering process. An amorphous metal deposit of nominal composition Ni 0 81 La 0 09 Kr 0 10 has been selected for further studies because of the high krypton loading, high sputtering yield, relatively low cost of the metallic components, resistance to corrosion, and stability of the product. The krypton release from this amorphous metal is described as an activated diffusion process which increases linearly with the square root of time. Studies of krypton release rate as a function of temperature were completed and an activation energy for the diffusion of 70 kcal/mole obtained. From these data, we estimated that the krypton release during the first ten years would be 0.5% for a maximum temperature of 350 0 C. The actual release of the krypton during storage was projected to be lower by a factor of 10 7 with the maximum temperature only 220 0 C. Thermal analysis studies show two energy releases occurring with krypton-containing alloys: one associated with recrystallization of the amorphous alloy and a second associated with krypton release. The total energy release between 100 and 800 0 C was less than 50 cal/g. Estimates are given for the cost of operation of the ion implantation process for solidification of the krypton-85 from a 2000-tonne heavy metal/year reprocessing plant. The present value costs, in 1981 dollars including capital and operating costs and assuming a 30-year life, are about $26M for the lifetime of the plant. Annual energy consumption of the process was estimated to be 3.9 M kWh/year

Toward compact and ultra-intense laser-based soft x-ray lasers

Science.gov (United States)

Sebban, S.; Depresseux, A.; Oliva, E.; Gautier, J.; Tissandier, F.; Nejdl, J.; Kozlova, M.; Maynard, G.; Goddet, J. P.; Tafzi, A.; Lifschitz, A.; Kim, H. T.; Jacquemot, S.; Rousseau, P.; Zeitoun, P.; Rousse, A.

2018-01-01

We report here recent work on an optical field ionized (OFI), high-order harmonic-seeded EUV laser. The amplifying medium is a plasma of nickel-like krypton obtained by OFI when focusing a 1 J, 30 fs, circularly-polarized, infrared pulse into a krypton-filled gas cell or krypton gas jet. The lasing transition is the 3d94d (J = 0) → 3d94p (J = 1) transition of Ni-like krypton ions at 32.8 nm and is pumped by collisions with hot electrons. The gain dynamics was probed by seeding the amplifier with a high-order harmonic pulse at different delays. The gain duration monotonically decreased from 7 ps to an unprecedented shortness of 450 fs full width at half-maximum as the amplification peak rose from 150 to 1200 with an increase of the plasma density from 3 × 1018 to 1.2 × 1020 cm-3. The integrated energy of the EUV laser pulse was also measured, and found to be around 2 μJ. It is to be noted that in the ASE mode, longer amplifiers were achieved (up to 2 cm), yielding EUV outputs up to 14 μJ.

Immobilization technology for krypton in amorphous zeolite

International Nuclear Information System (INIS)

Takusagawa, Atsushi; Ishiyama, Keiichi

1989-01-01

Radioactive krypton recovered from the offgas of a reprocessing plant requires long-term storage on the order of 100 years. Immobilization technology for krypton into amorphous zeolite 5A is considered one of the best methods for long-term storage. In this report, conditions for immobilization treatment and stability of amorphous zeolite 5A loaded krypton against heat, radiation and water are discussed, and a treatment system using this technology is described. (author)

High-power and highly efficient diode-cladding-pumped holmium-doped fluoride fiber laser operating at 2.94 microm.

Science.gov (United States)

Jackson, Stuart D

2009-08-01

A high-power diode-cladding-pumped Ho(3+), Pr(3+)-doped fluoride glass fiber laser is demonstrated. The laser produced a maximum output power of 2.5 W at a slope efficiency of 32% using diode lasers emitting at 1,150 nm. The long-emission wavelength of 2.94 microm measured at maximum pump power, which is particularly suited to medical applications, indicates that tailoring of the proportion of Pr(3+) ions can provide specific emission wavelengths while providing sufficient de-excitation of the lower laser level.

LPI Thresholds in Longer Scale Length Plasmas Driven by the Nike Laser*

Science.gov (United States)

Weaver, J.; Oh, J.; Phillips, L.; Afeyan, B.; Seely, J.; Kehne, D.; Brown, C.; Obenschain, S.; Serlin, V.; Schmitt, A. J.; Feldman, U.; Holland, G.; Lehmberg, R. H.; McLean, E.; Manka, C.

2010-11-01

The Krypton-Fluoride (KrF) laser is an attractive driver for inertial confinement fusion due to its short wavelength (248nm), large bandwidth (1-3 THz), and beam smoothing by induced spatial incoherence. Experiments with the Nike KrF laser have demonstrated intensity thresholds for laser plasma instabilities (LPI) higher than reported for other high power lasers operating at longer wavelengths (>=351 nm). The previous Nike experiments used short pulses (350 ps FWHM) and small spots (<260 μm FWHM) that created short density scale length plasmas (Ln˜50-70 μm) from planar CH targets and demonstrated the onset of two-plasmon decay (2φp) at laser intensities ˜2x10^15 W/cm^2. This talk will present an overview of the current campaign that uses longer pulses (0.5-4.0 ns) to achieve greater density scale lengths (Ln˜100-200 μm). X-rays, emission near ^1/2φo and ^3/2φo harmonics, and reflected laser light have been monitored for onset of 2φp. The longer density scale lengths will allow better comparison to results from other laser facilities. *Work supported by DoE/NNSA and ONR.

Ionization relaxation in shock-heated krypton-argon mixtures

International Nuclear Information System (INIS)

Ezumi, Hiromichi; Kawamura, Masahiko; Yokota, Toshiaki.

1977-01-01

The ionization relaxation processes behind shock waves in pure krypton and krypton-argon mixtures have been investigated using a Mach-Zehnder interferometer technique. The incident shock velocity was fixed in the neighborhood of Us=2800 m/sec, and the initial pressure was fixed at 0.95 Torr. The experimental results were compared with theoretical values based on the two-step collisional ionization model taking into account of the wall boundary-layer effect. The slope constants of excitation cross section against relative kinetic energy between krypton atom-atom collisions, krypton atom-electron collisions, and krypton-argon atom-atom collisions were determined to be 4.2 x 10 -19 cm 2 /eV, 1.2 x 10 -17 cm 2 /eV, and 4.2 x 10 -19 cm 2 /eV, respectively. (auth.)

Solubility of krypton in hydrofracture grout at elevated pressures

International Nuclear Information System (INIS)

Fitzgerald, C.L.; Mailen, J.C.

1982-01-01

The solubilities of krypton in water, simulated waste solution, and simulated grout at about 25 0 C and to pressures of 150 atm have been determined. The results of these studies show that preliminary calculations of krypton solubility based on the aqueous component of the hydrofracture grout were overly pessimistic. The volume of noble gas generated annually by the reference reprocessing plant would be soluble in the annual hydrofracture grout injection at ORNL at about 10 atm. The amount of krypton in the gas phase would depend on the amount of air in the hydrofracture grout mixture. At 34 atm, and with a small air volume relative to the injected krypton, the krypton would constitute about 30% of the gas bubbles. The disposal of krypton via injection with hydrofracture grout seems to be a viable process. The next logical steps would be to determine the krypton diffusion rate at injection conditions, and possibly to perform a test injection. At present, the schedule for future work is uncertain since funds for this project have been reduced significantly

Overview of the Nike KrF laser program

International Nuclear Information System (INIS)

Sethian, J.D.; Lehmberg, R.H.; Pawley, C.J.; Bodner, S.E.; McLean, E.A.; Pronko, M.S.; Gerber, K.A.; Deniz, A.V.; Hardgrove, J.; McGeoch, M.W.

1994-01-01

Nike is a large angularly multiplexed Krypton-Fluoride (KrF) laser under development at the Naval Research Laboratory. It is designed to explore the technical and physics issues of direct drive laser fusion. When completed, Nike will deliver 2-3 kJ of 248 nm light in a 4 nsec pulse with intensities exceeding 2 x 10 14 W/cm 2 onto a planar target. Spatially and temporally incoherent light will be used to reduce the ablation pressure nonuniformities to less than 2% in the target focal plane. The Nike laser consists of a commercial oscillator/amplifier front end, an array of gas discharge amplifiers, two electron beam pumped amplifiers (one with a 20x20 cm 2 aperture, the other with a 60x60 cm 2 aperture) and the optics required to relay, encode, and decode the beam. Approximately 90% of the system is operational and currently undergoing tests: the system is complete through the 20 cm amplifier, the 60 cm amplifier has completed all the necessary electron beam/pulsed power tests, and is currently being developed into a laser amplifier, and most of the optics have been installed. It is anticipated that Nike will be fully operational in the fall of 1994

Potential for beneficial use of krypton-85

International Nuclear Information System (INIS)

Tingey, G.L.; Jensen, G.A.; McClanahan, E.D.; Lytle, J.M.; Rising, K.R.

1983-03-01

Large quantities of krypton-85 (about 42 MCi) are contained in stored power-reactor fuels and about 1 MCi/year in fuels processed at each of the Savannah River and Hanford defense fuel-processing plants. This nuclear byproduct could be a significant material resource if used in specialized applications. Recently a technique for implanting krypton in a growing sputter-deposited metallic film has been developed. This yields a stable, high-concentration source of krypton-85 which may have applications for small power generators. Metal deposits containing up to 14 at. % have been prepared that would give a heat source of 0.9 W/cm 3 if fully enriched krypton-85 were implanted. Potential applications for up to 10-W batteries include power for runway lighting and other specialized military applications in remote locations, power for telephone or radiocommunications in the far North, and power for monitoring equipment for tracking animals. Krypton-85 has the advantage of being environmentally the most acceptable heat-producing radioisotope available for power production. 1 figure

Development of krypton-85 measurement in ocean samples by beta counting and use of the krypton-85 as a tracer in oceanography

International Nuclear Information System (INIS)

Ternon, Jean-Francois

1990-01-01

Krypton-85 present in the environment has essentially an anthropogenic origin, and the knowledge of the evolution of its concentration in the atmosphere, and of its mode of penetration in the ocean by gaseous exchange at the surface, and its bio-geochemical stability in the environment make it a potential tool to trace movements of water masses in the ocean. This research thesis aims at being a contribution to the implementation of an experimental device which would allow very low concentrations of krypton-85 in the ocean to be measured. After a presentation of the general context, the author reports the development of the two last steps of krypton-85 measurement: the separation of krypton by gas chromatography, and the measurement of krypton-85 by low-level radioactive counting. Then, the author reports the study of the use of krypton-85 as a tracer in oceanography, and notably highlights its similarities with CFC which are widely used to study ocean circulation [fr

Spectroscopic properties and quenching processes of Yb{sup 3+} in Fluoride single crystals for laser applications

Energy Technology Data Exchange (ETDEWEB)

Bensalah, A. [Physical Chemistry of Luminescent Materials, Claude Bernard/Lyon1 University, UMR 5620, CNRS Bat. A. Kastler, 10 rue Ampere, 69622 Villeurbanne (France) and Institute for Multidisciplinary Research of Advanced Materials, Tohoku University, Sendai 980-8577 (Japan)]. E-mail: amina-bensalah@enscp.fr; Ito, M. [Physical Chemistry of Luminescent Materials, Claude Bernard/Lyon1 University, UMR 5620, CNRS Bat. A. Kastler, 10 rue Ampere, 69622 Villeurbanne (France); Guyot, Y. [Physical Chemistry of Luminescent Materials, Claude Bernard/Lyon1 University, UMR 5620, CNRS Bat. A. Kastler, 10 rue Ampere, 69622 Villeurbanne (France); Goutaudier, C. [Physical Chemistry of Luminescent Materials, Claude Bernard/Lyon1 University, UMR 5620, CNRS Bat. A. Kastler, 10 rue Ampere, 69622 Villeurbanne (France); Jouini, A. [Physical Chemistry of Luminescent Materials, Claude Bernard /Lyon1 University, UMR 5620, CNRS Bat. A. Kastler, 10 rue Ampere, 69622 Villeurbanne (France); Institute for Multidisciplinary Research of Advanced Materials, Tohoku University, Sendai 980-8577 (Japan); Brenier, A. [Physical Chemistry of Luminescent Materials, Claude Bernard/Lyon1 University, UMR 5620, CNRS Bat. A. Kastler, 10 rue Ampere, 69622 Villeurbanne (France); Sato, H. [Institute for Multidisciplinary Research of Advanced Materials, Tohoku University, Sendai 980-8577 (Japan); Fukuda, T. [Institute for Multidisciplinary Research of Advanced Materials, Tohoku University, Sendai 980-8577 (Japan); Boulon, G. [Physical Chemistry of Luminescent Materials, Claude Bernard /Lyon1 University, UMR 5620, CNRS Bat. A. Kastler, 10 rue Ampere, 69622 Villeurbanne (France)

2007-01-15

Spectroscopic characterization is carried out to identify Stark's levels of Yb{sup 3+} transitions in several fluoride crystals grown either by the Czochralski technique or by the laser-heated pedestal growth method. Yb{sup 3+} concentration dependence of the decay time is analyzed in order to understand involved concentration quenching mechanisms. Laser tests under saphire:Ti pumping are presented for all our materials as well as under diode pumping for Yb:CaF{sub 2}.

Evaluation of crystalline changes and resistance to demineralization of the surface of human dental enamel treated with Er:YAG laser and fluoride using x-ray diffraction analysis and Vickers microhardness

Science.gov (United States)

Behroozibakhsh, Marjan; Shahabi, Sima; Ghavami-Lahiji, Mehrsima; Sadeghian, Safura; Sadat Faal Nazari, Neda

2018-06-01

This study aimed to investigate the changes in crystalline structure and resistance to demineralization of human dental surface enamel treated with erbium-doped yttrium aluminium garnet laser (Er:YAG) laser and fluoride. The enamel surfaces were divided into four groups according to the treatment process including, (L): irradiated with Er:YAG; (F): treated with acidulated phosphate fluoride gel (LF): Pre-irradiated surfaces with Er:YAG subjected to acidulated phosphate fluoride gel and (FL): laser irradiation was performed on the fluoridated enamel surface. Before and after the treatment procedure, the samples were evaluated using X-ray diffraction, scanning electron microscope (SEM) and the Vickers microhardness test. The surface microhardness values also were measured after a pH-cycling regime and acid challenge. The a-axis of all lased groups was contracted after treatment procedure. Measurement of the area under the peaks showed the highest crysallinity in the FL group. The hardness values of all laser treated samples significantly reduced after treatment procedure compared to the F group (p  ⩽  0.001). The morphological observations showed remarkable changes on the lased enamel surfaces including cracks, craters and exposed prisms. These findings suggest, irradiation of the Er:YAG laser accompanying with fluoride application can induce some beneficial crystalline changes regarding the acid-resistance properties of enamel, however, the craters and cracks produced by laser irradiation can promote enamel demineralization and consequently the positive effects of the Er:YAG laser will be eliminated.

Inhibition of enamel demineralisation using "Nd-YAG and diode laser assisted fluoride therapy".

Science.gov (United States)

Chand, B R; Kulkarni, S; Mishra, P

2016-02-01

This in vitro study was to evaluate the irradiation efficacy of the Diode laser and the Nd-YAG laser either un-assisted or assisted by acidulated phosphate fluoride (APF) treatment on enamel's acid resistance. Seventy-two enamel samples, obtained from 12 extracted human molars, were randomly assigned to 6 groups as follows: (1) Control (C); (2) Exposed to APF gel (F); (3) Diode laser (DL); (4) Irradiated with Diode laser through APF gel (DL/F); (5) Nd-YAG laser (NL) and (6) Irradiated with Nd-YAG laser through APF gel (NL/F). The specimens were individually demineralised in an acidified hydroxyethylcellulose system, and the acid resistance was evaluated by determining the calcium ion dissolution using atomic absorption spectrometry. The average concentration of the calcium ion determined in groups 1 to 6 was 901, 757, 736, 592, 497 and 416 parts per million micrograms/gram, respectively. The results showed that demineralisation in the NL/F group was significantly less than the other groups and the control group was significantly greater than the other groups (P laser irradiation, used alone or in combination with APF, in decreasing the enamel demineralisation was greater than all the other groups.

氪离子激光光凝治疗糖尿病视网膜病变疗效观察%Clinical research in the treatment of diabetic retinopathy with krypton lasers photocoagulation

Institute of Scientific and Technical Information of China (English)

李翠英

2013-01-01

目的 观察氪离子激光治疗糖尿病视网膜病变(DR)的效果.方法 荧光素眼底血管造影(FFA)确诊为Ⅲ～Ⅴ期DR96例(184只眼),术前查视力、裂隙灯、眼底和FFA,根据病变部位、性质、屈光介质情况选择不同波长激光进行全视网膜光凝(PRP),术后随访6～36个月.结果 治疗后184只眼视力提高60只眼,占32.61％；视力无变化90只眼,占48.91％；视力下降34只眼,占18.48％.结论 氪离子激光治疗可提高或保护DR患者的视功能.%Objective To observe the effects of krypton lasers on diabetic retinopathy. Methods 96 cases (184 eyes) of diabetic retinopathy in the stages of Ⅲ - Ⅴ were reviewed and identified by fundus fluorescein angiography (FFA). The visual acuity, slit-lamp, ophthalmoscopy and fundus fluorescein angiography were performed preoperatively. They were treated with krypton lasers paneretinal photocoagulation, according to the characteristics and the different manifestations of the affected eyes. The follow-up period was 6-36 months. Results Visual acuity improved in 60 eyes (32.61% ), remained with no changes in 90 eyes (48.91% ), and decreased in 34 eyes (18.48% ). Conclusion The krypton lasers is a safe and effective approach in treating diabetic retinopathy. It can improve or retain patients vision.

Report of the krypton club: availability of sup(81m)krypton in europe

International Nuclear Information System (INIS)

Clark, J.; Watson, I.

1982-01-01

An active group of producers of krypton 81m generators has been formed. They met in Liege 27th February 1981 to discuss the technical and logistics problems in making krypton 81m generators more widely available in Europe. A resume of that meeting was prepared and distributed at two major medicine meetings in 1981, Pisa and Berne, in an attempt to alert potential users to the current situation and encourage them to make contact with the production centre most favourably situated logistically. (Author)

SEM Evaluation of Enamel Surface Changes and Enamel Microhardness around Orthodontic Brackets after Application of CO2 Laser, Er,Cr:YSGG Laser and Fluoride Varnish: An In vivo Study.

Science.gov (United States)

Kaur, Tarundeep; Tripathi, Tulika; Rai, Priyank; Kanase, Anup

2017-09-01

One of the most undesirable consequences of orthodontic treatment is occurrence of enamel demineralization around orthodontic brackets. Numerous in vitro studies have reported the prevention of enamel demineralization by surface treatment with lasers and fluoride varnish. To evaluate the changes on the enamel surface and microhardness around orthodontic brackets after surface treatment by CO 2 laser, Er, Cr:YSGG laser and fluoride varnish in vivo. A double blind interventional study was carried out on 100 premolars which were equally divided into five groups, out of which one was the control group (Group 0). The intervention groups (Group I to IV) comprised of patients requiring fixed orthodontic treatment with all 4 first premolars extraction. Brackets were bonded on all 80 premolars which were to be extracted. Enamel surface treatment of Groups I, II and III was done by CO 2 laser, Er, Cr:YSGG laser and 5% sodium fluoride varnish respectively and Group IV did not receive any surface treatment. A modified T-loop was ligated to the bracket and after two months, the premolars were extracted. Surface changes were evaluated by Scanning Electron Microscopic (SEM) and microhardness testing. Comparison of mean microhardness between all the groups was assessed using post-hoc test with Bonferroni correction. Group I showed a melted enamel appearance with fine cracks and fissures while Group II showed a glossy, homogenous enamel surface with well coalesced enamel rods. Group III showed slight areas of erosions and Group IV presented areas of stripped enamel. Significant difference was observed between the mean microhardness (VHN) of Group I, Group II, Group III, Group IV and Group 0 with p<0.001. A significant difference of p<0.001 was observed while comparing Group I vs II,III,IV,0 and Group II vs III,IV,0. However, difference while comparing Group III vs IV was p=0.005 and difference between the mean microhardness of Group 0 vs Group III was non significant. Surface

Potential of CO2 lasers (10.6 µm associated with fluorides in inhibiting human enamel erosion

Directory of Open Access Journals (Sweden)

Thayanne Monteiro RAMOS-OLIVEIRA

2014-01-01

Full Text Available This in vitro study aimed to investigate the potential of CO2 lasers associated with different fluoride agents in inhibiting enamel erosion. Human enamel samples were randomly divided into 9 groups (n = 12: G1-eroded enamel; G2-APF gel; G3-AmF/NaF gel; G4-AmF/SnF2 solution; G5-CO2 laser (λ = 10.6 µm+APF gel; G6-CO2 laser+AmF/NaF gel; G7-CO2laser+AmF/SnF2solution; G8-CO2 laser; and G9-sound enamel. The CO2 laser parameters were: 0.45 J/cm2; 6 μs; and 128 Hz. After surface treatment, the samples (except from G9 were immersed in 1% citric acid (pH 4.0, 3 min. Surface microhardness was measured at baseline and after surface softening. The data were statistically analyzed by one-way ANOVA and Tukey’s tests (p < 0.05. G2 (407.6 ± 37.3 presented the highest mean SMH after softening, followed by G3 (407.5 ± 29.8 and G5 (399.7 ± 32.9. Within the fluoride-treated groups, G4 (309.0 ± 24.4 had a significantly lower mean SMH than G3 and G2, which were statistically similar to each other. AmF/NaF and APF application showed potential to protect and control erosion progression in dental enamel, and CO2 laser irradiation at 0.45J/cm2 did not influence its efficacy. CO2 laser irradiation alone under the same conditions could also significantly decrease enamel erosive mineral loss, although at lower levels.

Status of the Aurora laser system: Angular-multiplexed multikilojoule krypton fluoride prototype for inertial fusion

International Nuclear Information System (INIS)

Rosocha, L.A.; Goldstone, P.D.; Kristal, R.

1986-01-01

In this presentation, the authors report on the present status of the Aurora system including: The operation of the final stage 1-X 1-m laser at the 10-kJ level; the generation of 5-ns pulses by the front end; integration of the front end, multiplexer, amplifiers, and the extraction of long-pulse energy from the amplifier chain. Progress on the design and construction of the demultiplexer are also reported

An evaluation of krypton propellant in Hall thrusters

Science.gov (United States)

Linnell, Jesse Allen

Due to its high specific impulse and low price, krypton has long sparked interest as an alternate Hall thruster propellant. Unfortunately at the moment, krypton's relatively poor performance precludes it as a legitimate option. This thesis presents a detailed investigation into krypton operation in Hall thrusters. These findings suggest that the performance gap can be decreased to 4% and krypton can finally become a realistic propellant option. Although krypton has demonstrated superior specific impulse, the xenon-krypton absolute efficiency gap ranges between 2 and 15%. A phenomenological performance model indicates that the main contributors to the efficiency gap are propellant utilization and beam divergence. Propellant utilization and beam divergence have relative efficiency deficits of 5 and 8%, respectively. A detailed characterization of internal phenomena is conducted to better understand the xenon-krypton efficiency gap. Krypton's large beam divergence is found to be related to a defocusing equipotential structure and a weaker magnetic field topology. Ionization processes are shown to be linked to the Hall current, the magnetic mirror topology, and the perpendicular gradient of the magnetic field. Several thruster design and operational suggestions are made to optimize krypton efficiency. Krypton performance is optimized for discharge voltages above 500 V and flow rates corresponding to an a greater than 0.015 mg/(mm-s), where alpha is a function of flow rate and discharge channel dimensions (alpha = m˙alphab/Ach). Performance can be further improved by increasing channel length or decreasing channel width for a given flow rate. Also, several magnetic field design suggestions are made to enhance ionization and beam focusing. Several findings are presented that improve the understanding of general Hall thruster physics. Excellent agreement is shown between equipotential lines and magnetic field lines. The trim coil is shown to enhance beam focusing

Desublimation of krypton from a noncondensable carrier gas

International Nuclear Information System (INIS)

Eby, R.S.

1978-09-01

A study was conducted to obtain column concentration profiles and point buildup rates for a cold trap freezing out krypton from a nitrogen carrier gas stream and to compare those experimentally obtained profiles with profiles generated from a theoretical model. Profiles were obtained over a range of flow conditions from 0.14 to 1.06 standard cubic feet per minute, krypton feed gas concentrations varied from 5.2 to 13.5%, and cold trap operating temperatures from -281 to -312 0 F. Gamma scintillation techniques using tracer amounts of krypton-85 provided the major analytical tool employed in the investigation. Data obtained from the experiments indicate that if values for the density and thermal conductivity of the krypton frost are known, the model can accurately predict krypton loading profiles in the cold trap. The frost density and frost conductivity appear to be functions of the freeze-out temperature and condensable krypton concentration. A discussion of cold trapping theory, a description of the experimental apparatus and tests performed, and an explanation of the usefulness of the model as a design tool for engineering use are included

Fluoride materials for high peak power lasers, 17 May 1976--31 January 1977

International Nuclear Information System (INIS)

Folweiler, R.C.

1977-02-01

Single crystal fluoride optical materials were grown for potential application to laser fusion. Fluoride materials are of interest for this application, in general, because their low non-linear indices of refraction permit their use in optical components which can sustain very high peak powers without causing beam distortion. Emphasis was placed on Nd:YLF because its emission wave-lengths match the gain curve of promising amplifier materials. In addition to material growth, new feed preparation techniques were investigated and developed and certain material properties measured. The laser material, Nd:YLF, (Nd 3+ in LiYF 4 ) was grown and fabricated into laser rods. This material has laser emission at 1.047 μm and 1.053 μm, depending on the polarization selected. The former wavelength matches the peak emission wavelength of developmental Nd fluoroberyllate glasses, the latter matches Nd phosphate and fluorophosphate glasses that have low values of n 2 . The non-linear index of pure LiYF 4 was measured by Milam and Weber as 0.59 x 10 -13 esu. The concentration of Nd 3+ was varied from 1% to 4%. At higher concentrations and larger diameters a radial strain was found, sufficient to cause spiral cracking. This strain was apparently generated by a radial gradient of Nd 3+ ions. The distribution coefficient observed in one sample was 0.38. The stimulation emission coefficients were determined. Boules of KY 3 F 10 and KTb 3 F 10 were grown, with the latter suitable as a Faraday rotator material with projected low n 2 and larger Verdet constant. Experiments were performed on the systemKF-CeF 3 as a potential Faraday rotator material, and a cubic phase observed. The Ce 3+ ion has slightly lower rotary power/ion, but significantly lower cost

Analysis of 81Kr in groundwater using laser resonance ionization spectroscopy

International Nuclear Information System (INIS)

Kramer, S.D.; Hurst, G.S.; Chen, C.H.

1985-10-01

A new analytical technique based on resonant ionization of krypton with a vacuum ultraviolet (VUV) laser source was used to determine low-level 81 Kr concentrations in groundwater. The long half-life (210,000 years) and low concentration (1.3 x 10 3 81 Kr atoms per liter of modern water at 10 0 C) make the detection of 81 Kr by radioactive counting techniques extremely difficult. In this method, krypton gas was removed from water taken from an underground Swiss aquifer using standard cryogenic and chromatographic techniques. Stable krypton isotopes were then reduced by a factor of 10 7 by a two-stage isotopic enrichment cycle using a commercially available mass spectrometer. The enriched gas containing about 10 8 stable krypton atoms and about 10 3 atoms of 81 Kr was implanted into a silicon disc. This disc was then placed in the high vacuum final counting chamber and the krypton was released by laser annealing. This chamber contained a quadrupole mass spectrometer which used a pulsed VUV laser source as the ionizer. The measured signal indicated that the sample contained 1200 (+-300) atoms of 81 Kr

The study of radiochemical separation methods on gaseous Fission product krypton-88

International Nuclear Information System (INIS)

Yang Zhihong; Zhang Shengdong; Yang Lei; Ding Youqian; Sun Hongqing; Ma Peng

2012-01-01

Half-life of krypton-88 is 2.84 hours, high fission yields and a relatively large gamma branching ratio is had. The gas is short-lived fission products in burnup measurements. Only New fission products can extract from extraction in gas of fissile irradiation target. But krypton-88 with krypton-85, krypton-87, xenon -135, and xenon-138 is coexisted together, thus radiochemical separation must quickly taken. selected the irradiation time is 1-2 hours and cooling time is best 2 hours for sample preparation, krypton and xenon were separated using activated carbon adsorption, the ratio of krypton and xenon were measured by gamma spectroscopy. Then according to the ratio of krypton-85 and xenon-125 count rate coefficient around separation were calculated yield of krypton and decontamination factor of xenon and the final the yield of krypton-85 is calculated. (authors)

Ventilation studies of the lung with krypton-81m

International Nuclear Information System (INIS)

Klopper, J.F.; Baard, W.P.; Van Heerden, P.D.R.

1981-01-01

During a 2-year study period it was found that krypton-81m was useful in clinical practice. During this period 1563 technetium-99m perfusion studies and 807 krypton-81m ventilation studies were performed. A distinct advantage of krypton-81m was the ease with which multiple views could be obtained. These views could be directly compared with those of preceding perfusion studies. However, interruptions in the regular supply of rubidium-81/krypton-81m generators affected 17,1% of perfusion studies and xenon-127 should be a suitable substitute for these periods

Measurement of krypton-85 in the atmosphere with a portable apparatus

International Nuclear Information System (INIS)

Okai, T.

1984-01-01

A portable apparatus was developed for the rapid collection, separation and counting of krypton-85 in environmental air samples. The apparatus consists of a molecular sieve trap for the elimination of H 2 O and CO 2 , a charcoal trap for the collection of krypton, a chromatographic column for the isolation of krypton in the air sample and a vial for the disolution of krypton in the scintillation solution. With this apparatus, krypton can be collected from half a cubic meter of air with 94% recovery in about 3 hrs. The measurements of krypton-85 were done several time in Fukuoka area from Jan. 30 to Dec. 9, 1981. The krypton-85 concentration was found to be approximately 21 pCi/m 3 air. The results were compared with those obtained by foreign investigators. (author)

Application of Various Lasers to Laser Trimming Resistance System

Institute of Scientific and Technical Information of China (English)

SUN Ji-feng

2007-01-01

Though the laser trimming resistance has been an old laser machining industry for over 30 years, the development of technology brings new alternative lasers which can be used for the traditional machining. The paper describes application of various lasers to laser trimming resistance system including early traditional krypton arc lamp pumped Nd:YAG to laser, modern popular diode pumped solid state laser and the present advanced harmonic diode pumped solid state laser. Using the new alternative lasers in the laser trimming resistance system can dramatically improve the yields and equipment performance.

Atmospheric krypton-85 during 1962 and 1963

Energy Technology Data Exchange (ETDEWEB)

Ehhalt, D.; Muennich, K. O.; Roether, W.; Schoelch, J.; Stich, W.

1963-11-15

The krypton-85 found in the atmosphere presumably originates from two different sources, namely fission bomb tests and processing of burned-out fuel elements from nuclear reactors. This paper discusses the impact of the sources of krypton in the atmosphere in greater detail.

Lasers in Ophthalmology

Institute of Scientific and Technical Information of China (English)

无

1992-01-01

In recent years,lasers have entered every fieldof medicine and especially so in ophthalmol-ogy.The scientific basis of lasers in ophthal-mology is based on three mechanisms:1.Photothermal effectLasers:argon,krypton,dye and diodeA thermal effect is generated when laserenergy is absorbed by pigment leading to in-creased vibration and therefore heat content.A

Physical properties and heat transfer characteristics of materials for krypton-85 storage

International Nuclear Information System (INIS)

Christensen, A.B.

1977-09-01

Krypton-85 decay results in heat generation, and the subsequent temperature increase in the krypton-85 storage media must be evaluated. This report compiles the physical properties of krypton and of potential krypton-85 storage materials which are required to calculate the maximum temperature developed during storage. Temperature calculations were made for krypton-85 stored as a gas or immobilized solid in steel storage cylinders. The effects of krypton-85 loading, cylinder radius, storage media properties, and exterior cooling on storage temperature were shown

The atmosphere of Mars - Detection of krypton and xenon

Science.gov (United States)

Owen, T.; Biemann, K.; Biller, J. E.; Lafleur, A. L.; Rushneck, D. R.; Howarth, D. W.

1976-01-01

Krypton and xenon have been discovered in the Martian atmosphere with the mass spectrometer on the second Viking lander. Krypton is more abundant than xenon. The relative abundances of the krypton isotopes appear normal, but the ratio of xenon-129 to xenon-132 is enhanced on Mars relative to the terrestrial value for this ratio. Some possible implications of these findings are discussed.

Spatial diagnostics of the laser induced lithium fluoride plasma

Energy Technology Data Exchange (ETDEWEB)

Baig, M. A.; Qamar, Aisha; Fareed, M. A.; Anwar-ul-Haq, M.; Ali, Raheel [Atomic and Molecular Physics Laboratory, Department of Physics, Quaid-i-Azam University, 45320 Islamabad (Pakistan)

2012-06-15

We present spatial characteristics of the lithium fluoride plasma generated by the fundamental and second harmonic of a Nd:YAG laser. The plume emission has been recorded spatially using five spectrometers covering the spectral region from 200 nm to 720 nm. The electron density is measured from the Stark broadened line profile of the line at 610.37 nm, whereas the plasma temperature has been determined using the Boltzmann plot method including all the observed spectral lines of lithium. Both the plasma parameters; electron density and plasma temperature decrease with the increase of the distance from the target surface. The thermal conduction towards the target, the radiative cooling of the plasma, and the conversion of thermal energy into kinetic energy are the main mechanisms responsible for the spatially decrease of the plasma parameters.

Partitioning of krypton-85 in liquid scintillation cocktail

International Nuclear Information System (INIS)

Hohorst, F.A.; Sherlock, M.A.

1994-12-01

Krypton is one of the noble gases. As such, it forms compounds only with exceptionally strong oxidizing agents. The concentration of krypton in air is 1.139 parts per million by volume. In general, its behavior is best described as that of an ideal gas. Krypton-85 is the longest lived of the common radioactive noble gases with a half life of 10.72 years. Gamma radiation at 513.990 keV has an intensity of only 0.434%. Most decay is β - emission with a maximum energy of 687.0 keV and an average energy of 251.4 keV. The analytical chemistry of krypton-85 is driven by these factors. High concentrations may be gamma counted directly. Low levels are typically determined by more sensitive techniques such as liquid scintillation counting (LSC) where detection limits on the order of 1 picocurie (pCi) are routinely achieved. For a 5 standard cubic centimeter (scc) sample, this represents a concentration of 0.2 pCi/scc, well below the DOE Air Immersion Derived Concentration Guideline (G) of 3 pCi/scc. As a gas, krypton in a sealed LSC vial distributes itself between the liquid phase and the gas phase. Some past work has used gamma counting at levels many orders of magnitude greater than those now achievable by LSC to study the distribution of krypton. This effect is of interest in the analytical chemistry of krypton-85 because geometrical considerations influence how much of the material in the gas phase decays generating particles which then impact the liquid phase where they may be counted

Electra Laser Facility

Data.gov (United States)

Federal Laboratory Consortium — FUNCTION: The Electra Laser Facility is used to develop the science and technology needed to develop a reliable, efficient, high-energy, repetitively pulsed krypton...

Radioactive 85Kr in krypton enriched with a light isotope

International Nuclear Information System (INIS)

Kuz'minov, V.V.; Novikov, V.M.; Pomanskii, A.A.; Pritychenko, B.V.; Vieiar, J.; Garcia, E.; Morales, A.; Morales, J.; Nunes-Lagos, R.; Piumendon, J.

1993-01-01

Radioactive krypton 85, a product of nuclear power generation, is known to be accumulating in the atmosphere continuously. Its volumetric activity in natural krypton is 700-800 Bq/liter. This can cause difficulties, e.g., in the fabrication of nuclear radiation detector for high-mass krypton. Krypton with a reduced 85 Kr content can be obtained by isotope separation. As part of an experiment to look for two-positron decay and conversion of an atomic electron to a positron in 78 Kr, Saenz measured the 85 Kr content in 78 Kr-enriched krypton. A mixture of two 85 Kr samples was used as the working substance of a cylindrical ionization chamber. The useful volume (1.33 liter) of the chamber contained 35.3 liters of gas at ∼2.5 kPa. The energy resolution of the detector at an energy of 0.511 MeV was 3.8%. The measurements were made in a passive lead shield 20 cm thick in an underground laboratory at a depth of 675 m water equivalent. Results are presented for counting rates in low-energy regions, contribution of krypton-85 to background, and the volumetric activity of krypton-85

Krypton Ion Thruster Performance

Science.gov (United States)

Patterson, Michael J.; Williams, George J.

1992-01-01

Preliminary data were obtained from a 30 cm ion thruster operating on krypton propellant over the input power range of 0.4 to 5.5 kW. The data presented are compared and contrasted to the data obtained with xenon propellant over the same input power envelope. Typical krypton thruster efficiency was 70 percent at a specific impulse of approximately 5000 s, with a maximum demonstrated thrust to power ratio of approximately 42 mN/kW at 2090 s specific impulse and 1580 watts input power. Critical thruster performance and component lifetime issues were evaluated. Order of magnitude power throttling was demonstrated using a simplified power-throttling strategy.

Separation of krypton from carbon dioxide and oxygen with molecular sieves

International Nuclear Information System (INIS)

Forsberg, C.W.

1976-01-01

Molecular sieves were investigated to separate 1 percent mixtures of krypton in gas streams of a few percent oxygen and 90+ percent carbon dioxide. Such a system will be required to concentrate the krypton gas between radioactive krypton off-gas cleanup systems such as KALC (Krypton Absorption in Liquid Carbon Dioxide) and any krypton gas bottling station. Linde 5A molecular sieves were found capable of selectively removing the CO 2 from the gas stream while partially separating the oxygen from the krypton; i.e., effecting a three-component gas separation. This use of molecular sieves differs from standard practice in two respects. First, the bulk of the gas (greater than 90 percent) is removed by molecular sieves rather than the normal practice of using molecular sieves to remove trace impurities. Second, in a single bed two separations occur simultaneously, CO 2 from other gases and krypton from oxygen. The use of molecular sieves for separating krypton and carbon dioxide is superior to alternatives such as CO 2 freezeout and chemical traps when there are only moderate gas flows and there is a need for very high reliability and ease of maintenance

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)

Update and improvement of the global krypton-85 emission inventory

International Nuclear Information System (INIS)

Ahlswede, Jochen; Hebel, Simon; Ross, J. Ole; Schoetter, Robert; Kalinowski, Martin B.

2013-01-01

Krypton-85 is mainly produced in nuclear reactors by fission of uranium and plutonium and released during chopping and dissolution of spent fuel rods in nuclear reprocessing facilities. As noble gas it is suited as a passive tracer for evaluation of atmospheric transport models. Furthermore, research is ongoing to assess its quality as an indicator for clandestine reprocessing activities. This paper continues previous efforts to compile a comprehensive historic emission inventory for krypton-85. Reprocessing facilities are the by far largest emitters of krypton-85. Information on sources and calculations used to derive the annual krypton-85 emission is provided for all known reprocessing facilities in the world. In addition, the emission characteristics of two plants, Tokai (Japan) and La Hague (France), are analysed in detail using emission data with high temporal resolution. Other types of krypton-85 sources are power reactors, naval reactors and isotope production facilities. These sources contribute only little or negligible amounts of krypton-85 compared to the large reprocessing facilities. Taking the decay of krypton-85 into account, the global atmospheric inventory is estimated to about 5500 PBq at the end of 2009. The correctness if the inventory has been proven by meteorological simulations and its error is assumed to be in the range of a few percent. - Highlights: ► Krypton-85 is mainly produced in nuclear reactors and released during reprocessing. ► Krypten-85 can be possibly used as an indicator for clandestine reprocessing. ► This work provides an up-to-date global krypton-85 emission inventory. ► The inventory includes emissions from all possible artificial sources.

Radioactivity 85Kr in krypton enriched with light isotope

International Nuclear Information System (INIS)

Kuz'minov, V.V.; Novikov, V.M.; Pomanskij, A.A.

1992-01-01

85 Kr content in krypton enriched with 78 Kr is measured within the frames of experiment for search of binary position decay and conversion of atomic electron into 78 Kr. Voluminous activity in krypton enriched up to 98% 78 Kr equal to 0.206 -0.004 +0.001 Bq/L is obtained which is by 4000 less as compared to natural krypton. 7 refs.; 1 fig.; 1 tab

Solid state storage of radioactive krypton in a silica matrix

International Nuclear Information System (INIS)

Tingey, G.L.; Lytle, J.M.; Gray, W.J.; Wheeler, K.R.

1980-12-01

The feasibility of loading a low density SiO 2 glass with krypton for storage of radioactive 85 Kr has been demonstrated by studies using non-radioactive krypton. A 96% SiO 2 glass with 28% porosity was heated at an elevated pressure of Kr gas to a temperature of 850 to 900 0 C and held at that temperature to sinter the glass-krypton composite to a density of about 2 g/cm 3 . A krypton content of 30 cm 3 of Kr(STP)/cm 3 of glass has been demonstrated when loading pressures of 140 MPa are used. Krypton release rates from the glass are lower than reported for any other waste form considered currently. At 420 0 C a diffusion parameter, D/r 0 2 , of 8.66 x 10 -13 min -1 was determined which leads to a total release of 0.7% of the krypton in 10 years. Release rates increase moderately with increasing temperature up to 600 0 C and increase rapidly above 600 0 C. The lower loading pressures (about 40 MPa) may appear to yield a more favorable product from the point of view of krypton release than the high pressures. Advantages and disadvantages of the technique are given in the conclusions section

The distribution, atmospheric transfer, and assessment of krypton-85

International Nuclear Information System (INIS)

Pannetier, R.

1968-06-01

Techniques for sampling and measuring krypton-85 have been developed which allowed to determine its geographical distribution. From its use as a tracer, an evaluation of the air masses which cross over the subtropical fronts has been derived. Besides, the stratospheric character of air pollution by krypton-85 at the level of the antarctic soil has been shown out. Levels of krypton-85 seem to point out to an underestimation of the assessment of nuclear explosion fission energies as adopted by the United Nations Scientific committee on the effects of atomic radiation and emphasize the need to set limits as soon as possible to the amounts of krypton-85 released to the atmosphere by fuel-reprocessing plants. (author) [fr

Spectra of heliumlike krypton from tokamak fusion test reactor plasmas

International Nuclear Information System (INIS)

Bitter, M.; Hsuan, H.; Bush, C.; Cohen, S.; Cummings, C.J.; Grek, B.; Hill, K.W.; Schivell, J.; Zarnstorff, M.; Smith, A.; Fraenkel, B.

1993-04-01

Krypton has been injected into ohmically-heated TFTR plasmas with peak electron temperatures of 6 key to study the effects of krypton on the plasma performance and to investigate the emitted krypton line radiation, which is of interest for future-generation tokamaks such as ITER, both as a diagnostic of the central ion temperature and for the control of energy release from the plasma by radiative cooling. The emitted radiation was monitored with a bolometer array, an X-ray pulse height analysis system, and a high-resolution Johann-type crystal spectrometer; and it was found to depend very sensitively on the electron temperature profile. Satellite spectra of heliumlike krypton, KrXXXV, near 0.95 Angstrom including lithiumlike, berylliumlike and boronlike features were recorded in second order Bragg reflection. Radiative cooling and reduced particle recycling at the plasma edge region were observed as a result of the krypton injection for all investigated discharges. The observations are in reasonable agreement with modeling calculations of the krypton ion charge state distribution including radial transport

Simultaneous fabrication of laser-active colour centres and permanent microgratings in lithium fluoride by a single femtosecond pulse

International Nuclear Information System (INIS)

Kurobori, Toshio; Kawamura, Ken-ichi; Hirano, Masahiro; Hosono, Hideo

2003-01-01

We report, for the first time, simultaneous fabrication of laser-active F 2 and F 3 + colour centres in lithium fluoride and permanent periodic gratings with fringe spacings as fine as sub-micron size by two interfering infrared femtosecond (fs) laser pulses. In particular, the optical properties (absorption and luminescence) of F 2 and F 3 + colour centres produced by a single fs laser pulse are compared with those created by damage from radiation such as x-rays. The present technique of simultaneously fabricating laser-active colour centres and functional fine-periodic structures in photo-insensitive transparent materials may well be a useful method for making miniaturized optical devices. (letter to the editor)

Determination of low levels of krypton in helium by gas chromatography

International Nuclear Information System (INIS)

Evans, D.L.; Mukherji, A.K.

1980-01-01

Krypton-helium mixture was used as an adsorbate for surface area measurement--. The surface area measurements depend on the accuracy with which the krypton concentration is known. Generally gas tanks supplied by Union Carbide provide a nominal value of 0.1% krypton in helium. The surface area measurements require, however, that the krypton concentraion be known to +- 0.001% or better. A standard plot of krypton volume in microliters vs the area under the curve as measured by a planimeter using the helium detector and Molecular Sieve 5A column was obtained. Results with a thermal conductivity detector using Molecular Sieve 5A and Carbon Molecular Sieve are also given. Low levels of krypton in helium can be measured with precision using either a helium or a thermal conductivity detector with Molecular Sieve 5A or Carbon Molecular Sieve columns. 2 figures, 1 table

Update and improvement of the global krypton-85 emission inventory.

Science.gov (United States)

Ahlswede, Jochen; Hebel, Simon; Ross, J Ole; Schoetter, Robert; Kalinowski, Martin B

2013-01-01

Krypton-85 is mainly produced in nuclear reactors by fission of uranium and plutonium and released during chopping and dissolution of spent fuel rods in nuclear reprocessing facilities. As noble gas it is suited as a passive tracer for evaluation of atmospheric transport models. Furthermore, research is ongoing to assess its quality as an indicator for clandestine reprocessing activities. This paper continues previous efforts to compile a comprehensive historic emission inventory for krypton-85. Reprocessing facilities are the by far largest emitters of krypton-85. Information on sources and calculations used to derive the annual krypton-85 emission is provided for all known reprocessing facilities in the world. In addition, the emission characteristics of two plants, Tokai (Japan) and La Hague (France), are analysed in detail using emission data with high temporal resolution. Other types of krypton-85 sources are power reactors, naval reactors and isotope production facilities. These sources contribute only little or negligible amounts of krypton-85 compared to the large reprocessing facilities. Taking the decay of krypton-85 into account, the global atmospheric inventory is estimated to about 5500 PBq at the end of 2009. The correctness if the inventory has been proven by meteorological simulations and its error is assumed to be in the range of a few percent. Copyright © 2012 Elsevier Ltd. All rights reserved.

Technical feasibility of krypton-85 storage in sodalite

International Nuclear Information System (INIS)

Benedict, R.W.; Christensen, A.B.; Del Debbio, J.A.; Keller, J.H.; Knecht, D.A.

1979-01-01

Based on these experimental results, the process that is technically feasible for a reference 2000 metric ton of heavy metal (MTHM) per year reprocessing plant producing approx. 17 MCi or approx. 190 m 3 at STP would encapsulate krypton at approx. 20 cm 3 /g from krypton at temperatures greater than 575 0 C and pressures greater than 1600 atm with one batch a day in a 58-L high pressure vessel. Based on preliminary measurements at 500 0 C, the same process also would be feasible for a 70% krypton and 30% xenon mixture. 7 figures

Recent progress on the Los Alamos Aurora ICF [inertial confinement fusion] laser system

International Nuclear Information System (INIS)

Rosocha, L.A.; Blair, L.S.

1987-01-01

Aurora is the Los Alamos short-pulse, high-power, krypton-fluoride laser system. It serves as an end-to-end technology demonstration prototype for large-scale ultraviolet laser systems for short wavelength inertial confinement fusion (ICF) investigations. The system is designed to employ optical angular multiplexing and serial amplification by electron-beam-driven KrF laser amplifiers to deliver stacked, 248-nm, 5-ns duration multikilojoule laser pulses to ICF-relevant targets. This paper presents a summary of the Aurora system and a discussion of the progress achieved in the construction and integration of the laser system. We concentrate on the main features of the following major system components: front-end lasers, amplifier train, multiplexer, optical relay train, demultiplexer, and the associated optical alignment system. During the past year, two major construction and integration tasks have been accomplished. The first task is the demonstration of 96-beam multiplexing and amplified energy extraction, as evidenced by the integrated operation of the front end, the multiplexer (12-fold and 8-fold encoders), the optical relay train, and three electron-beam-driven amplifiers. The second task is the assembly and installation of the demultiplexer optical hardware, which consists of over 300 optical components ranging in size from several centimeters square to over a meter square. 13 refs., 13 figs

Krypton retention on solid adsorbents

International Nuclear Information System (INIS)

Monson, P.R. Jr.

1981-08-01

Over a dozen prospective adsorbents for krypton were studied and evaluated with respect to adsorption capacity and cost for dissolver off-gas streams from nuclear reprocessing plants. Results show that, at subambient temperature (-40 0 to -80 0 C), the commercially available hydrogen mordenite has sufficient adsorptive capacity to be the most cost-effective material studied. Silver mordenite has a higher capacity for krypton retention, but is 50 times more expensive than hydrogen mordenite. The results indicate that a solid adsorbent system is feasible and competitive with other developing systems whih utilize fluorocarbon absorption and cryogenic distillation

Beam-foil level lifetimes in krypton III

International Nuclear Information System (INIS)

Coetzer, F.J.; Kotze, P.B.; Westhuizen, P. van der

1982-01-01

The radiative lifetimes of levels in doubly-ionized Krypton have been measured after foil excitation of a beam of Krypton particles in the wavelength range 120-500 nm. The results are compared with the experimental values obtained by Fink et al., as well as theoretical values resulting from Coulomb (C.A.) and single configuration Hartree-Fock (H.F.) calculations. (orig.)

Environmental consequences of atmospheric krypton-85

International Nuclear Information System (INIS)

Boeck, W.L.

1978-01-01

This project examines the thesis that atmospheric background ionization is relevant to the understanding of weather. Projections of future world-wide use of nuclear energy imply that sufficient krypton-85 will be produced and may be released to significantly alter the natural ionization background. The scope of the project includes an assessment of krypton-85 on the electrical aspects of the atmosphere as well as the consequences of an altered electrical state of the atmosphere. The results of a first approximation model for the effects of krypton-85 on the atmosphere show that the electric field at the surface of the ocean would be reduced by about 25 percent and at a continental station by about 15 percent. At about two kilometers altitude, the electric field would be reduced by about 14 percent over the oceans and 16 percent over the land. The effects decrease quickly with increasing altitude. Analytical studies of the equations for fair weather atmospheric electricity yield solutions suitable for the interpretation of time dependent phenomena with periods longer than a few seconds. A brief analysis shows that a perfect assessment is not necessary to make an error-free decision regarding krypton-85 control measures. From the viewpoint of a decision-maker, those aspects that could swing the decision from one alternative to another are priority areas for analysis

outcome of diode laser cyclophotocoagulation in neovascular ...

African Journals Online (AJOL)

Duke

including, ruby, ND:YAG, argon, krypton and, more recently, trans scleral cyclophotocoagulation with the diode laser, which has been shown to be more effective with less side effects than the others. The diode laser, 810nm, has. 4,5 greater melanin absorption compared to other lasers. Of the various cyclodestructive laser ...

Solid sources of krypton-85; Sources solides de krypton-85; Tverdye istochniki kriptona-85; Fuentes solidas de cripton-85

Energy Technology Data Exchange (ETDEWEB)

Puig, J R; Sandier, J [Centre d' Etudes Nucleaires de Saclay (France)

1962-01-15

Krypton-85, a {beta}-emitter with a long half-life and low biological hazard, has considerable industrial potentialities. It is difficult, however, to manufacture sources since the element occurs in gaseous form and cannot be chemically fixed. The authors describe a method of krypton-fixation in a macromolecular matrix formed by mass polymerization of a liquid monomer containing krypton; they also give an account of the preparation of two types of source produced in this way-one enclosed in polystyrene, the other in polyvinyl acetate. Such sources lose krypton; the activity of the first decreases by 8 % daily, that of the second by 3 % daily. These apparent decays enable the diffusion coefficients of krypton in these polymers to be calculated. Diffusion appears to be prevented by the cross-linkages which exist in the polymers. (author) [French] Le krypton-85, emetteur {beta} de longue periode et de faible danger biologique, offre des avantages importants pour une utilisation industrielle. Mais la fabrication de sources est difficile du fait que cet element se presente sous forme gazeuse et qu'il ne peut etre fixe chimiquement. Les auteurs exposent une methode de fixation du krypton dans une matrice macromoleculaire formee par la polymerisation en masse d'un monomere liquide contenant le krypton, et decrivent les preparations de deux types de sources realisees sur ce principe - l'une enfermee dans du polystyrene, l'autre dans de l'acetate de polyvinyle. Les sources ainsi obtenues laissent echapper du krypton; leur activite diminue de 8% par jour pour la premiere et de 3% par jour pour la seconde. Ces decroissances apparentes permettent de calculer les coefficients de diffusion du krypton dans ces polymeres. Celle-ci parait empechee par les liaisons de pontage existant dans le polymere. (author) [Spanish] El cripton-85 es un emisor beta de periodo largo y poco peligroso desde el punto de vista biologico, que ofrece considerables ventajas para su empleo en la

[Effect of krypton-containing gas mixture on Japanese quail embryo development].

Science.gov (United States)

Kussmaul', A R; Gur'eva, T S; Dadasheva, O A; Pavlov, N B; Pavlov, B N

2008-01-01

Investigated were effects of gas mixture with up to 3.0 kgs/cm2 of krypton on the embryonic development of domesticated Japanese quail (Coturnix coturnix japonica dom.). Results demonstrated absence of a serious krypton effect on Japanese quail embryos. Development of embryos proceeded in due course; morphometrically the experimental embryos were essentially similar to controls. It should be noted that despite exposure to acute hypoxic hypoxia during the initial 12 hours of development in the krypton-containing gas mixture, viability of quail embryos was high enough which can be ascribed to the krypton protective action. Besides, an additional experiment showed that krypton partial pressure of 5-5.5 kgs/cm2 produces the narcotic effect on adult Japanese quails.

Adsorption of krypton from helium by low temperature charcoal

International Nuclear Information System (INIS)

Cooper, M.H.; Simmons, C.R.; Taylor, G.R.

1975-01-01

Adsorption of krypton from helium by charcoal at temperatures from -100 0 C to -140 0 C was experimentally investigated to verify adsorption system design methods and to determine effects of regeneration for the Gas Purification System of the Liquid-Metal Fast Breeder Reactor. Helium with two krypton concentrations, traced by krypton-85 at 0.0044 μCi/cm 3 , was passed through a 1/2-inch diameter, three-inch long trap packed with coconut charcoal. Breakthrough curves were measured by continuously recording the activity of the effluent gas using a sampler with a krypton-85 detection limit of about 5 x 10 -7 μCi/cm 3 . Experimental breakthrough curves with continuous feed for both concentrations and for superficial gas velocities of 5 to 28 cm/sec were closely fitted when the pore diffusion term was omitted from the Anzelius linear equilibrium adsorption model indicating that the adsorption process for this system was controlled by gas phase mass transport kinetics. Adsorption capacities determined in these experiments at -140 0 C agreed closely with published data. A discontinuity, however, was observed in the krypton adsorption coefficient between -100 and -120 0 C. This discontinuity may be caused by capillary condensation of krypton in the charcoal pores. Breakthrough times for pulse experiments at 400 ppM (vol.) krypton concentration were several times greater than breakthrough for continuous feed experiments at equivalent conditions. The differences in breakthrough times indicate that the adsorption isotherms are non-linear in this concentration range. Regeneration experiments showed that purging with helium at room temperature for 16 hours was inadequate, since lower breakthrough times were obtained after this treatment. Regeneration under vacuum at 100 0 C or 200 0 C for 16 hours resulted in satisfactory regeneration (i.e., no reduction in breakthrough times occurred in subsequent runs). (U.S.)

Improved laser damage threshold performance of calcium fluoride optical surfaces via Accelerated Neutral Atom Beam (ANAB) processing

Science.gov (United States)

Kirkpatrick, S.; Walsh, M.; Svrluga, R.; Thomas, M.

2015-11-01

Optics are not keeping up with the pace of laser advancements. The laser industry is rapidly increasing its power capabilities and reducing wavelengths which have exposed the optics as a weak link in lifetime failures for these advanced systems. Nanometer sized surface defects (scratches, pits, bumps and residual particles) on the surface of optics are a significant limiting factor to high end performance. Angstrom level smoothing of materials such as calcium fluoride, spinel, magnesium fluoride, zinc sulfide, LBO and others presents a unique challenge for traditional polishing techniques. Exogenesis Corporation, using its new and proprietary Accelerated Neutral Atom Beam (ANAB) technology, is able to remove nano-scale surface damage and particle contamination leaving many material surfaces with roughness typically around one Angstrom. This surface defect mitigation via ANAB processing can be shown to increase performance properties of high intensity optical materials. This paper describes the ANAB technology and summarizes smoothing results for calcium fluoride laser windows. It further correlates laser damage threshold improvements with the smoothing produced by ANAB surface treatment. All ANAB processing was performed at Exogenesis Corporation using an nAccel100TM Accelerated Particle Beam processing tool. All surface measurement data for the paper was produced via AFM analysis on a Park Model XE70 AFM, and all laser damage testing was performed at Spica Technologies, Inc. Exogenesis Corporation's ANAB processing technology is a new and unique surface modification technique that has demonstrated to be highly effective at correcting nano-scale surface defects. ANAB is a non-contact vacuum process comprised of an intense beam of accelerated, electrically neutral gas atoms with average energies of a few tens of electron volts. The ANAB process does not apply mechanical forces associated with traditional polishing techniques. ANAB efficiently removes surface

Facility for the separation of krypton and recuperation of xenon

International Nuclear Information System (INIS)

Boell-Djoa, S.H.

1977-01-01

A facility is described by means of which the fission inert gases krypton 85 and xenon from spent fuel particles can be separated by fractionated freezing-out and subsequent distillation to such an extent that the xenon contains less than 1 ppb krypton 85. Then, in accordance with the stringent regulations, the krypton can be conveyed to definitive storage in special bottles, whereas the xenon can be released for industrial uses. (orig.) [de

Ambient krypton-85 air sampling at Hanford

International Nuclear Information System (INIS)

Trevathan, M.S.; Price, K.R.

1984-10-01

In the fall of 1982, the Environmental Evaluations Section of Pacific Northwest Laboratory (PNL) initiated a network of continuous krypton-85 air samplers located on and around the Hanford Site. This effort was in response to the resumption of operations at a nuclear fuel reprocessing plant located onsite where krypton-85 was to be released during fuel dissolution. Preoperational data were collected using noble gas samplers designed by the Environmental Protection Agency-Las Vegas (EPA-LV). The samplers functioned erratically resulting in excessive maintenance costs and prompted a search for a new sampling system. State of the art krypton-85 sampling methods were reviewed and found to be too costly, too complex and inappropriate for field application, so a simple bag collection system was designed and field tested. The system is composed of a reinforced, heavy plastic bag, connected to a variable flow pump and housed in a weatherproof enclosure. At the end of the four week sampling period the air in the bag is transferred by a compressor into a pressure tank for easy transport to the laboratory for analysis. After several months of operation, the air sampling system has proven its reliability and sensitivity to ambient levels of krypton-85. 3 references, 3 figures, 1 table

Short wavelength laser calculations for electron pumping in neon-like krypton (Kr XXVII)

Science.gov (United States)

Feldman, U.; Bhatia, A. K.; Suckewer, S.

1983-01-01

Calculations of electron impact collision strengths and spontaneous radiative decay rates are made for neon-like krypton (Kr XXVII) for the 2s2 2p6, 2s2 2p5 3s, 2s2 2p5 3p, and 2s2 2p5 3d configurations. From these atomic data, the level populations as a function of the electron density are calculated at two temperatures, 1 x 10 to the 7th K and 3 x 10 to the 7th K. An analysis of level populations reveals that a volume of krypton in which a significant number of the ions are in the Kr XXVII degree of ionization can produce a significant gain in transition between the 2s2 2p5 3s and 2s2 2p5 3p configurations. At an electron density of 1 x 10 to the 19th/cu cm the plasma length has to be of the order of 1 m; at a density of 1 x 10 to the 21st/cu cm the length is reduced to approximately 0.5 cm; and at an electron density of 1 x 10 to the 22nd/cu cm the length of the plasma is further reduced to approximately 1 mm.

Cylindrical ionization chamber with compressed krypton

International Nuclear Information System (INIS)

Kuz'minov, V.V.; Novikov, V.M.; Pomanskii, A.A.; Pritychenko, B.V.; Viyar, J.; Garcia, E.; Morales, A.; Morales, J.; Nunes-Lagos, R.; Puimedon, J.; Saens, K.; Salinas, A.; Sarsa, M.

1993-01-01

A cylindrical ionization chamber with a grid is used to search for double positron decay and atomic electron conversion to a positron in 78 Kr. Krypton is the working gas material of the chamber. The spectrometric characteristics of the chamber filled with krypton and xenon are presented. The energy resolution is 2.1% for an energy of 1.84 MeV (the source of γ-quanta is 88 Y) when the chamber is filled with a mixture of Kr+0.2% H 2 under a pressure of 25 atm

The clinical observation of the premacular hemorrhage cured by krypton Laser%氪激光治疗黄斑部视网膜前出血的临床观察

Institute of Scientific and Technical Information of China (English)

周才喜

2010-01-01

Objective To approach the clinical effect,indication and opportunity of the premacular hemorrhage cured by krypton laser.Methods The data of 15 patients (15 eyes) with premacular hemorrhage (PMH) cured by krypton laser were retrospectively analyzed from Jan 2008 to Jun 2009.Results Eleven (73.33%) of 15 eyes were succeed.Thirteen eyes which the shape of PMH similar to boat,among them 11 eyes (84.61%) whose course less than 21 days were succeed and the best corrected visual acuity of 10 eyes recov- ered to the level of pre-hemorrhage.the average were 0.67.Two eyes which shape of PMH alike irregular curve or ring and 2 eyes which shape of PMH similar to boat but the course over 28 days were failed.Conclusions The method that the PMH cured by krypton laser is economical,simple,safe and effective.The cure rate is great which the course less than 21 days and the shape of PMH alike boat.%目的 探讨氪激光治疗黄斑部视网膜前出血的临床疗效、适应证及治疗时机.方法 对2008年1月至2009年6月期间接受氪激光治疗的黄斑部视网膜前出血患者15例15只眼的临床资料进行回顾性分析.结果 接受激光治疗的15只眼,11只眼(73.33%)治疗成功.13只眼出血呈舟状者,11只眼(84.61%)病程少于21d者治疗成功;其中10只眼最佳矫正视力恢复至出血前水平,平均0.67.2只眼出血呈不规则弧形或环形者和2只眼病程超过28d的舟状出血者治疗失败.结论 氪激光治疗黄斑部视网膜前出血经济、简单、安全、有效.其中病程少于21d、出血呈舟状者激光治疗成功率高.

Krypton recovery from reprocessing off-gases by cryogenic distillation

International Nuclear Information System (INIS)

Geens, L.P.; Goossens, W.R.A.; Marien, J.

1987-01-01

With the financial support of the C.E.C., krypton recovery by cryogenic distillation in presence of oxygen was investigated. Both oxygen and ozone behavior in the cryodistillation unit were observed. The ozone decay in the rectification column was studied in absence and in presence of a radiation source. Additionally a demonstration run with krypton-85 was performed. Experiments with different oxygen concentrations up to 21% volume in the feed gas were carried out. The oxygen was enriched up to 85% volume in a zone between the krypton layer and the entrance of the rectification column. No oxygen was found in the bottom product. On the other hand, the ozone accumulated in that bottom product. The decay of ozone in the bottom liquid was measured in absence and in presence of a 500 Ci thulium-170 source. Without the radiation source, it took almost 30 days to observe a decay from 0.90% volume to 0.45% volume. The decay rate decreased with decreasing ozone concentration. In presence of the 500 Ci thulium-170, a constant decay rate of 0.24% volume per day was measured. Finally, a demonstration run with 100 Ci krypton-85 was performed in the cryodistillation unit, with air as feed gas. The krypton-85 was fed at a concentration of 30 mCih -1 until the total krypton inventory of the rectification column amounted to 40-45 Ci. The active run had a duration of 900 hours, during which no operational problems occurred. (orig.)

Accurate virial coefficients of gaseous krypton from state-of-the-art ab initio potential and polarizability of the krypton dimer

Science.gov (United States)

Song, Bo; Waldrop, Jonathan M.; Wang, Xiaopo; Patkowski, Konrad

2018-01-01

We have developed a new krypton-krypton interaction-induced isotropic dipole polarizability curve based on high-level ab initio methods. The determination was carried out using the coupled-cluster singles and doubles plus perturbative triples method with very large basis sets up to augmented correlation-consistent sextuple zeta as well as the corrections for core-core and core-valence correlation and relativistic effects. The analytical function of polarizability and our recently constructed reference interatomic potential [J. M. Waldrop et al., J. Chem. Phys. 142, 204307 (2015)] were used to predict the thermophysical and electromagnetic properties of krypton gas. The second pressure, acoustic, and dielectric virial coefficients were computed for the temperature range of 116 K-5000 K using classical statistical mechanics supplemented with high-order quantum corrections. The virial coefficients calculated were compared with the generally less precise available experimental data as well as with values computed from other potentials in the literature {in particular, the recent highly accurate potential of Jäger et al. [J. Chem. Phys. 144, 114304 (2016)]}. The detailed examination in this work suggests that the present theoretical prediction can be applied as reference values in disciplines involving thermophysical and electromagnetic properties of krypton gas.

Generation of spectrally stable 6.5-fs visible pulses via filamentation in krypton

Institute of Scientific and Technical Information of China (English)

Keisuke Kaneshima; Kengo Takeuchi; Nobuhisa Ishii; Jiro Itatani

2016-01-01

We produced 5-μJ, 6.5-fs visible pulses at a repetition rate of 1 kHz using filamentation in a gas cell filled with krypton followed by spectral selection and phase compensation by a combination of dielectric mirrors. The visible pulses have a smooth spectrum from 520 to 650 nm with a shot-to-shot stability in each spectral component of better than 2%(standard deviation). This pulse compression scheme is simple and robust, and can be easily integrated into intense ultrashort-pulse laser systems.

The NIKE KrF laser program

International Nuclear Information System (INIS)

Sethian, J.D.; Bodner, S.E.; Gerber, K.A.; Lehmberg, R.H.; McLean, E.A.; Obenschain, S.P.; Pawley, C.J.; Pronko, M.S.; Stamper, J.A.; Deniz, A.V.; Hardgrove, J.; Lehecka, T.; McGeoch, M.W.

1994-01-01

NIKE is a large angularly multiplexed Krypton-Fluoride (KrF) laser under development at the Naval Research Laboratory. It is designed to explore the technical and physics issues of direct drive laser fusion. When completed, NIKE will deliver 2--3 kJ of 248 nm light in a 4 nsec pulse with intensities exceeding 2x10 14 W/cm 2 onto a planar target. Spatially and temporally incoherent light will be used to reduce the ablation pressure nonuniformities to less than 2% in the target focal plane. These parameters are predicted to be those required for a high gain ICF pellet. The NIKE system consists of a commercial oscillator/amplifier front end, an array of gas discharge amplifiers, two electron beam pumped amplifiers (one with a 20x20 cm 2 aperture, the other with a 60x60 cm 2 aperture) and the optics required to relay, encode, and decode the beam. Approximately two-thirds of the system is operational and currently undergoing tests. The output of the smaller e-beam system, the 20 cm Amplifier, exceeds both the uniformity and energy required to drive the final e-beam system, the 60 cm Amplifier. The pulsed power components of the 60 cm Amplifier have been built, and initial tests show the electron beam deposited by the system meets the laser requirements for pumping uniformity and energy deposition. copyright 1994 American Institute of Physics

Krypton retention on solid adsorbents

International Nuclear Information System (INIS)

Monson, P.R. Jr.

1982-01-01

An experimental laboratory program was conducted to develop economical solid adsorbents for the retention of krypton from a dissolver off-gas stream. The study indicates that a solid adsorbent system is feasible and competitive with other developing systems which utilize fluorocarbon absorption nd cryogenic distillation. This technology may have potential applications not only in nuclear fuel reprocessing plants, but also in nuclear reactors and in environmental monitoring. Of the 13 prospective adsorbents evaluated with respect to adsorption capacity and cost, the commercially available hydrogen mordenite was the most cost-effective material at subambient temperatures (-40 0 to -80 0 C). Silver mordenite has a higher capacity for krypton retention, but is 50 times more expensive than hydrogen mordenite

Krypton for computed tomography lung ventilation imaging: preliminary animal data.

Science.gov (United States)

Mahnken, Andreas H; Jost, Gregor; Pietsch, Hubertus

2015-05-01

The objective of this study was to assess the feasibility and safety of krypton ventilation imaging with intraindividual comparison to xenon ventilation computed tomography (CT). In a first step, attenuation of different concentrations of xenon and krypton was analyzed in a phantom setting. Thereafter, 7 male New Zealand white rabbits (4.4-6.0 kg) were included in an animal study. After orotracheal intubation, an unenhanced CT scan was obtained in end-inspiratory breath-hold. Thereafter, xenon- (30%) and krypton-enhanced (70%) ventilation CT was performed in random order. After a 2-minute wash-in of gas A, CT imaging was performed. After a 45-minute wash-out period and another 2-minute wash-in of gas B, another CT scan was performed using the same scan protocol. Heart rate and oxygen saturation were measured. Unenhanced and krypton or xenon data were registered and subtracted using a nonrigid image registration tool. Enhancement was quantified and statistically analyzed. One animal had to be excluded from data analysis owing to problems during intubation. The CT scans in the remaining 6 animals were completed without complications. There were no relevant differences in oxygen saturation or heart rate between the scans. Xenon resulted in a mean increase of enhancement of 35.3 ± 5.5 HU, whereas krypton achieved a mean increase of 21.9 ± 1.8 HU in enhancement (P = 0.0055). The use of krypton for lung ventilation imaging appears to be feasible and safe. Despite the use of a markedly higher concentration of krypton, enhancement is significantly worse when compared with xenon CT ventilation imaging, but sufficiently high for CT ventilation imaging studies.

Evaluation of activated charcoal for dynamic adsorption of krypton and xenon

International Nuclear Information System (INIS)

Khan, A.A.; Deshingkar, D.S.; Ramarathinam, K.; Kishore, A.G.

1975-01-01

From the standpoint of radiation safety, the release of radioactive krypton and xenon from power reactors should be kept as low as practicable. The decay of shortlived isotopes of krypton and xenon by adsorptive delay on activated charcoal has shown promising results for this purpose. The delay provided by activated charcoal is proportional to the dynamic adsorption coefficients of these gases which are characteristic of the adsorbent. These coefficients were determined for krypton and xenon on indigenous gas-adsorbing activated charcoal at different moisture contents of carrier air stream and activated charcoal, concentrations of krypton around ambient temperatures, to find its suitability for designing adsorber columns. (author)

Selective adsorption-desorption method for the enrichment of krypton

International Nuclear Information System (INIS)

Yuasa, Y.; Ohta, M.; Watanabe, A.; Tani, A.; Takashima, N.

1975-01-01

Selective adsorption-desorption method has been developed as an effective means of enriching krypton and xenon gases. A seriesof laboratory-scale tests were performed to provide some basic data of the method when applied to off-gas streams of nuclear power plants. For the first step of the enrichment process of the experiments, krypton was adsorbed on solid adsorbents from dilute mixtures with air at temperatures ranging from -50 0 C to -170 0 C. After the complete breakthrough was obtained, the adsorption bed was evacuated at low temperature by a vacuum pump. By combining these two steps krypton was highly enriched on the adsorbents, and the enrichment factor for krypton was calculated as the product of individual enrichment factors of each step. Two types of adsorbents, coconut charcoal and molecular sieves 5A, were used. Experimental results showed that the present method gave the greater enrichment factor than the conventional method which used selective adsorption step only. (U.S.)

An experimental investigation of proton-induced phenomena in krypton

International Nuclear Information System (INIS)

Mulders, J.J.L.

1985-01-01

In this thesis proton-induced phenomena in krypton gas are described. The considered reactions of protons on krypton are both nuclear and atomic. The nuclear conversion processes mainly result in the production of several Rb radioisotopes, such as 81 Rb that is used in 81 Rb-sup(81m)Kr generator systems for medical diagnostics. The irradiation of krypton gas (natural composition) with protons of about 26 MeV can be used for the routine production of 81 Rb from the direct production reaction 82 Kr(p,2n) 81 Rb and from the indirect reaction 82 Kr(p,2n)sup(81m)Rb → 81 Rb. To determine the scattering of protons in krypton gas targets a quantitative autoradiographic technique was developed. Proton profiles have been determined from the proton-induced activity distribution on a copper foil. For the on-line detection of produced Rb radioisotopes several optical detection techniques were investigated. (Auth.)

Non-equilibrium surface conditions and microstructural changes following pulsed laser irradiation and ion beam mixing of Ni overlayers on sintered alpha-SiC

International Nuclear Information System (INIS)

More, K.L.; Davis, R.F.

1986-01-01

Pulsed laser irradiation and ion beam mixing of thin Ni overlayers on sintered alpha-SiC have been investigated as potential surface modification techniques for the enhancement of the mechanical properties of the SiC. Each of these surface processing methods are nonequilibrium techniques; materials interactions can be induced at the specimen surface which are not possible with conventional thermal techniques. As a result of the surface modification, the physical properties of the ceramic can be altered under the correct processing conditions. Following laser irradiation using a pulsed ruby or krypton fluoride (KrF) excimer laser, the fracture strength of the SiC was increased by approximately 50 percent and 20 percent, respectively. However, ion-beam mixing of Ni on SiC resulted in no change in fracture strength. Cross-sectional transmission electron microscopy, scanning electron microscopy, secondary ion mass spectroscopy, and Rutherford backscattering techniques, have been used to characterize the extent of mixing between the Ni and SiC as a result of the surface modification and to determine the reason(s) for the observed changes in fracture strength. 19 references

Analysis of Krypton Laser Combined With ND:YAG Laser in the Treatment of Angle Closure Glaucoma Effect%氪激光联合ND：YAG激光治疗闭角型青光眼效果分析

Institute of Scientific and Technical Information of China (English)

张海涛; 刘岚; 王宇蕾

2015-01-01

青光眼位列全球不可逆致盲眼病第二位，致盲率高。我们用氪绿激光联合Nd：YAG激光，对原发性闭角型青光眼行周边虹膜成形术与周边虹膜切除术，采用超声生物显微镜（UBM）和房角镜对联合激光手术的有效性进行评价，结果证明联合激光治疗初次发作的急性闭角型青光眼安全、有效。%Glaucoma is a global irreversible blindness in the second rank, high rate of blindness. We use krypton green laser peripheral iris of primary angle closure glaucoma plasty. Combined Nd:YAG laser peripheral iris excision, the effectiveness of the combined laser surgery was evaluated by using the ultrasonic biological microscope (UBM) and the angle of the lens. The results show that the combined laser treatment of acute angle closure glaucoma is safe and effective.

Osiris and SOMBRERO inertial confinement fusion power plant designs

International Nuclear Information System (INIS)

Meier, W.R.; Bieri, R.L.; Monsler, M.J.

1992-03-01

Conceptual designs and assessments have been completed for two inertial fusion energy (IFE) electric power plants. The detailed designs and results of the assessment studies are presented in this report. Osiris is a heavy-ion-beam (HIB) driven power plant and SOMBRERO is a Krypton-Fluoride (KrF) laser-driven power plant. Both plants are sized for a net electric power of 1000 MWe

Using zeolites for fixation and long-term storage of krypton

International Nuclear Information System (INIS)

Pirogova, G.N.; Voronin, Yu.V.; Pribylov, A.A.; Serpinskii, V.V.; Mirskii, Ya.V.; Almazova, B.B.; Golitsina, V.V.

1993-01-01

It is known that large quantities of 85 Kr are liberated during the operation of nuclear power plants and, in particular, during the processing of nuclear fuel. At the present time, there are several methods of its fixation (accumulation), viz., storage in high-pressure gas balloons, adsorption, plasma-aided implantation into metals, introduction into clathrate compounds, and obtaining kryptonates. Encapsulation in zeolites is one of the most promising methods. The merits of this method include safety during storage, a favorable volume-to-mass ratio, the possibility of separating krypton from a mixture of different gases, and purity of the encapsulated gas. The encapsulation technique has been developed quite recently. Several recent reports established the possibility of encapsulating krypton in the 3A-type zeolites. However, most of the investigators observed leakage during the storage of the zeolite-gas system and complete liberation of krypton from the zeolite during prolonged storage. This paper deals with a study of the encapsulation process of krypton in the zeolites obtained by cation exchange from NaA. The experimental specimens were characterized by the degree of exchange of sodium into potassium and cesium. It is known that the introduction of cesium into the structure (body) of a zeolite reduces the size of the window of entrance. All the synthesized specimens were used in their granulated form. The aim of this study was to develop zeolite specimens for carrying out long-term storage of krypton

Contribution to the study of the structure of silver krypton solid solutions; Contribution a l'etude de la structure des solutions solides argent-krypton

Energy Technology Data Exchange (ETDEWEB)

Levy, V; Tullairet, J; Delaplace, J; Antolin-Baudier, J; Adda, Y [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1964-07-01

The silver-krypton solid solutions formed by electrical discharge have been studied by X-rays, electrical resistivity and electronic transmission microscopy. The crystalline parameter and residual resistivity measurements have shown that the krypton atom behaves very differently to those of other elements of the periodic classification when dissolved in silver. The recovery of the crystalline parameter and of the electrical resistivity has been studied as a function of temperature. (authors) [French] Les solutions solides argent, krypton, realisees par decharges electrique ont ete etudiees par Rayons X, resistivite electrique et microscopie electronique en transmission. Les mesures de parametre cristallin et de resistivite residuelle ont montre que le comportement de l'atome de krypton est tres different de celui des autres elements de la classification periodique en solution dans l'argent. La restauration du parametre cristallin et de la resistivite electrique en fonction de la temperature a ete etudiee. (auteurs)

Immobilization of krypton-85 in zeolite 5A

International Nuclear Information System (INIS)

Christensen, A.B.; Del Debbio, J.A.; Knecht, D.A.; Tanner, J.E.; Cossel, S.C.

1983-01-01

This paper describes the technical feasibility and presents a summary of a preconceptual design and cost estimate for a process to immobilize krypton-85 by sintering in zeolite 5A at 700 0 C and 100 MPa for 2 to 4 h. Krypton loading of 30 to 60 m 3 at STP per m 3 solid can be achieved. The initial water concentration in zeolite 5A has a catalytic effect on the sintering rate and must be kept at about 1 wt% by heating prior to the encapsulation run. High initial water loadings and/or encapsulation times longer than 4 h must be avoided because the sintered zeolite 5A recrystallizes to an anorthite-type feldspar and releases the trapped krypton. Data are presented to show how the process conditions affect krypton encapsulation in zeolie 5A and how to assure the quality of the product. By adding a powdered glass frit to the commercial zeolite 5A 2 mm beads, a solid mass is formed during encapsulation, which can be further compacted using standard hot isotatic pressing techniques at 33 MPa and 600 0 C to form a fused glassy matrix enclosing the amorphous zeolite. A process for encapsulating the annual krypton-85 production at a commercial 2000 metric ton of heavy metal spent fuel reprocessing plant is developed. A hot isostatic press (HIP) with an isolated work zone of 8 or 16 L capacity is required to operate for 600 or 300 cycles per year, respectively. Existing HIP technology uses work zones from 1 to 3500 L capacity at similar production rates. A combined encapsulation/compaction cycle is proposed as an option to most effectively immobilize the krypton and the zeolite. A preconceptual design and cost estimate is given for a commercial-scale Kr encapsulation facility. The facility is designed to withstand a worst case rupture of the HIP. The maximum lease is estimated to result in an off-site dose well below accident protective action guidance levels

Empirical evaluation of the radiative cooling coefficient for krypton gas in the FTU plasma

International Nuclear Information System (INIS)

Fournier, K.B.; Pacella, D.; Mazzitelli, G.; Stutman, D.; Soukanovskii, V.; Goldstein, W.H.

1997-01-01

For future fusion reactors, a careful balance must be achieved between the cooling of the outer plasma via impurity radiation and the deleterious effects of inevitable core penetration by impurity ions. We have injected krypton gas into the Frascati Tokamak Upgrade (FTU) plasma. The measured visible bremsstrahlung and bolometric signals from krypton have been inverted and the resulting radial impurity density profile and power loss profile for krypton gas are extracted. Using the measured electron density and temperature profiles, the radiative cooling coefficient for krypton is derived. The level of intrinsic impurities (Mo, Cr, Mn and Fe) in the plasma during the krypton puffing is monitored with a VUV SPRED spectrometer. Models for krypton emissivity from the literature are compared to our measured results. 7 figs

Environmental behaviour and dosimetry of Krypton-85

International Nuclear Information System (INIS)

Patek, P.

1980-12-01

Although 85 Kr has only small influence on the total radiation burden to man, monitoring and safety considerations have to be done, especially regarding the operation of fuel reprocessing plants. The natural, military and civilian sources of 85 Kr are discussed and a survey is given on the possibilities of Krypton removal from off-gas streams. Regarding the environmental behaviour of the released Krypton-amounts it was shown, that only the atmospheric dispersion is of influence to the succeeding irradiation of the population. Krypton is transferred to man only by inhalation and remains with different halflives in the human body. The highest absorbed dose is caused by beta-rays to the skin and in the airways of the lungs. While the highest dose equivalent rates to the most exposed individuals are reached by local sources from fuel reprocessing plants, the highest collective effective dose equivalent commitment is reached for global dispersed 85 Kr. (author)

Laser-optogalvanic studies of the 4p5 ns and nd autoionizing resonances in krypton

International Nuclear Information System (INIS)

Baig, M A; Hanif, M; Aslam, M

2008-01-01

We report new measurements of the odd-parity autoionizing resonances in krypton using resonant two-photon excitation from the 4p 5 5s[3/2] 2 metastable level in a mild DC discharge and an optogalvanic detection technique. We have observed the 4p 5 ns [1/2] 0,1 , 4p 5 nd [3/2] 2 and 4p 5 nd [5/2] 2,3 autoionizing resonances excited from three intermediate levels 4p 5 5p' [1/2] 1 , 4p 5 5p' [3/2] 1 and 4p 5 5p' [3/2] 2 . The spectra are notable for the absence of the broad autoionizing 4p 5 nd [3/2] 1 series which dominates in the photo-absorption spectrum from the ground state. The prominent transitions follow ΔK = ΔJ = Δl selection rules of the JK-coupling scheme. We report nearly 100 new energy levels in krypton besides the quantum defects and the reduced widths Γ r Γ(ν) 3 of the nd' [3/2] 2 , nd' [5/2] 2 and nd' [5/2] 3 Rydberg states

Internal plasma potential measurements of a Hall thruster using xenon and krypton propellant

International Nuclear Information System (INIS)

Linnell, Jesse A.; Gallimore, Alec D.

2006-01-01

For krypton to become a realistic option for Hall thruster operation, it is necessary to understand the performance gap between xenon and krypton and what can be done to reduce it. A floating emissive probe is used with the Plasmadynamics and Electric Propulsion Laboratory's High-speed Axial Reciprocating Probe system to map the internal plasma potential structure of the NASA-173Mv1 Hall thruster [R. R. Hofer, R. S. Jankovsky, and A. D. Gallimore, J. Propulsion Power 22, 721 (2006); and ibid.22, 732 (2006)] using xenon and krypton propellant. Measurements are taken for both propellants at discharge voltages of 500 and 600 V. Electron temperatures and electric fields are also reported. The acceleration zone and equipotential lines are found to be strongly linked to the magnetic-field lines. The electrostatic plasma lens of the NASA-173Mv1 Hall thruster strongly focuses the xenon ions toward the center of the discharge channel, whereas the krypton ions are defocused. Krypton is also found to have a longer acceleration zone than the xenon cases. These results explain the large beam divergence observed with krypton operation. Krypton and xenon have similar maximum electron temperatures and similar lengths of the high electron temperature zone, although the high electron temperature zone is located farther downstream in the krypton case

Characterization of long-scale-length plasmas produced from plastic foam targets for laser plasma instability (LPI) research

Science.gov (United States)

Oh, Jaechul; Weaver, J. L.; Serlin, V.; Obenschain, S. P.

2017-10-01

We report on an experimental effort to produce plasmas with long scale lengths for the study of parametric instabilities, such as two plasmon decay (TPD) and stimulated Raman scattering (SRS), under conditions relevant to fusion plasma. In the current experiment, plasmas are formed from low density (10-100 mg/cc) CH foam targets irradiated by Nike krypton fluoride laser pulses (λ = 248 nm, 1 nsec FWHM) with energies up to 1 kJ. This experiment is conducted with two primary diagnostics: the grid image refractometer (Nike-GIR) to measure electron density and temperature profiles of the coronas, and time-resolved spectrometers with absolute intensity calibration to examine scattered light features of TPD or SRS. Nike-GIR was recently upgraded with a 5th harmonic probe laser (λ = 213 nm) to access plasma regions near quarter critical density of 248 nm light (4.5 ×1021 cm-3). The results will be discussed with data obtained from 120 μm scale-length plasmas created on solid CH targets in previous LPI experiments at Nike. Work supported by DoE/NNSA.

Study on immobilization technology of krypton gas by ion-implantation and sputtering process

International Nuclear Information System (INIS)

Hayashi, S.; Kamiya, S.; Ikeda, S.; Nakanishi, Y.

1997-01-01

At the Waste Technology Development Division of PNC''s Tokai Works, we have been carrying out the development of the recovering and storing technology of radioactive krypton to reduce the radioactive gaseous effluent released to the environment arising from reprocessing of nuclear spent fuels. As a part of this technical development, the method of storing radioactive krypton is an encapsulation in a metal matrix which appears to offer the most secure immobilization of krypton. From the result of the ion-implantation test used non-radioactive krypton and the evaluation of electrical characteristics, we have selected the metallic materials, they are Nickel and Yttrium, and designed the vessel and the apparatus which continuously immobilized the krypton into metal matrix. This article described the following experiment result. (1) The long-term immobilization technology was established with respect to handling a equipment and plasma controlling. (2) Stability of the krypton immobilized alloy was considered satisfactory because the release was tolerably small. (author)

Evaluation of the efficacy of laser peripheral iridoplasty in reversing the darkroom provocative test result in Chinese patients with primary angle closure status post laser iridotomy

Institute of Scientific and Technical Information of China (English)

Ping; Huang; Ling-Ling; Wu

2015-01-01

AIM: To investigate the efficacy and safety of krypton laser peripheral iridoplasty(LPIP) for Chinese patients with primary angle closure(PAC) or primary angle-closure glaucoma(PACG) status post laser iridotomy in reversing the positive results of the dark room provocative test(DRPT).METHODS: This study was prospective, noncomparative,interventional case series. Thirty-three patients(thirty-eight eyes) with PAC or PACG status post patent laser iridotomy and maintained normal intraocular pressure(IOP) but with positive DRPT results were enrolled. All the subjects were treated with krypton LPIP. DRPT was repeated after krypton LPIP. Results of DRPT were recorded. The visual acuity, IOP and gonioscopy were analyzed before and after krypton LPIP. A minimum time limit for follow-up was 6mo.RESULTS: Thirty-three patients(thirty-eight eyes)were followed for 17.7 ±8.37mo(range 7-41mo) after LPIP. Positive results of DRPT decreased from 38 eyes to9 eyes(23.7%) after LPIP. Peripheral anterior synechiae of angle in 34 of 38 eyes(89.5%) remained unchanged at dynamic gonioscopy throughout the follow-up period after LPIP.CONCLUSION: LPIP decreased positive rates of the DRPT significantly. The mechanism may be that LPIP minimized contact between the peripheral iris and trabecular meshwork, which is a key factor for developing peripheral anterior synechiae.

Evaluation of the efficacy of laser peripheral iridoplasty in reversing the darkroom provocative test result in Chinese patients with primary angle closure status post laser iridotomy

Directory of Open Access Journals (Sweden)

Ping Huang

2015-06-01

Full Text Available AIM: To investigate the efficacy and safety of krypton laser peripheral iridoplasty (LPIP for Chinese patients with primary angle closure (PAC or primary angle-closure glaucoma (PACG status post laser iridotomy in reversing the positive results of the dark room provocative test (DRPT.METHODS:This study was prospective, noncomparative, interventional case series. Thirty-three patients (thirty-eight eyes with PAC or PACG status post patent laser iridotomy and maintained normal intraocular pressure (IOP but with positive DRPT results were enrolled. All the subjects were treated with krypton LPIP. DRPT was repeated after krypton LPIP. Results of DRPT were recorded. The visual acuity, IOP and gonioscopy were analyzed before and after krypton LPIP. A minimum time limit for follow-up was 6mo.RESULTS:Thirty-three patients (thirty-eight eyes were followed for 17.7±8.37mo (range 7-41mo after LPIP. Positive results of DRPT decreased from 38 eyes to 9 eyes (23.7% after LPIP. Peripheral anterior synechiae of angle in 34 of 38 eyes (89.5% remained unchanged at dynamic gonioscopy throughout the follow-up period after LPIP.CONCLUSION:LPIP decreased positive rates of the DRPT significantly. The mechanism may be that LPIP minimized contact between the peripheral iris and trabecular meshwork, which is a key factor for developing peripheral anterior synechiae.

Improved performance of the Aurora KrF/ICF laser system

International Nuclear Information System (INIS)

Jones, J.E.; Czuchlewski, S.J.; Turner, T.P.; Watt, R.G.; Thomas, S.J.; Netz, D.A.; Tallman, C.R.; Figueira, J.F.

1990-01-01

This paper reports on Aurora the Los Alamos National Laboratory short pulse high power krypton-fluoride laser system. It serves as an end-to-end technology demonstration prototype for large scale UV laser systems for short wavelength inertial confinement fusion (ICF) research. The system employs optical angular multiplexing and serial amplification by electron-beam driven KrF laser amplifiers. The 1-5-ns pulse of the Aurora front end is split into ninety-six beams which are angularly and temporally multiplexed to produce a 480-ns pulse train for amplification by four KrF laser amplifiers. The largest amplifier, the large aperture module (LAM), has a 1-m square aperture and a gain length of 2 m. In the present system configuration half (forty-eight) of the amplified pulses are demultiplexed using different optical path lengths and delivered simultaneously to target. The system has not been optimized, and several near term improvements are expected to result in significant increases in both delivered energy and target irradiance. Removing the twelve calorimeters from the lens plate and allowing forty-eight beams to go to target will increase delivered energy by 33%. Relatively minor modifications to the front end should result in a 30% increase in system output energy. Replacement of damaged optics will increase transmission into the preamplifier by at least 25%. New optics and reduction of retro-pulses will allow the preamplifier stage gain to be increased by 50%

Measurement of the deuterium concentration in water samples using a CW chemical deuterium fluoride laser

International Nuclear Information System (INIS)

Trautmann, M.

1979-10-01

In this study a new method for the determination of the deuterium content in water samples is described. The absorption of the radiation of a CW deuterium fluoride laser by the isotope HDO in the water vapor of the sample is measured by means of an optoacoustic detector (spectrophone). Thereby advantage is taken of the fact that H 2 O hardly absorbs the laser radiation and that D 2 O only exists in negligible concentrations. The isotope ratio of hydrogen can be calculated from the measured relative concentration of HDO. In the course of this investigation the relative absorption cross sections of HDO for the different laser lines were determined. It was thereby established that there exists a very good coincidence of an HDO absorption line with the 2P2 laser line. Using a very sensitive nonresonant spectrophone the relative concentration of HDO in natural water samples could be determined with an accuracy of about 10%. The experiments also demonstrated that with appropriate improvements made to the apparatus and using a second spectrophone as a reference it should be possible to increase this accuracy to 0,1%. (orig.)

Immobilization of krypton-85 in zeolite 5A and porous glass

International Nuclear Information System (INIS)

Christensen, A.B.; DelDebbio, J.A.; Knecht, D.A.; Tanner, J.E.; Cossel, S.C.

1981-12-01

This report demonstrates the technical and economic feasibility for immobilizing krypton-85 by high pressure/high temperature encapsulation in zeolite 5A or thirsty Vyco porous glass. Data are presented to show how process conditions affect the encapsulation and how to compact the zeolite beads with glass frit or other additives to form a fused mass with low dispersibility potential. Krypton specific loadings of 30 and 50 m 3 STP gas per m 3 solid are readily achieved at 100 MPa in porous glass at 900 0 C and zeolite 5A at 700 0 C. Krypton is encapsulated by a sintering process where the porous glass and zeolite 5A voids are sealed. With zeolite 5A, the initial water concentration has a catalytic effect on the sintering, resulting in a transition from crystalline zeolite 5A to an amorphous aluminosilicate. Krypton leakage experiments are used to predict leakage rates from glass or zeolite of less than 0.03% and 0.3% for 10-y storage at 300 and 400 0 C, respectively. Heating the loaded zeolite at 600 to 700 0 C for 4 h removes 0.1% of the total krypton which is loosely held and reduces the subsequent leakage rates at 300 to 400 0 C. Zeolite 5A is chosen as the preferred material to immobilize krypton-85. A preconceptual design and cost estimate is given for a facility to encapsulate 110% of the krypton production of a 2000 metric ton of heavy metal per year reprocessing plant, or 230 m 3 of gas containing 19 MCi of krypton-85. A hot isostatic press (HIP) with an isolated work zone of 8 or 16 L capacity is required to operate for 600 or 300 cycles per year, respectively. Existing HIP technology uses work zones from 1 to 3500 L capacity at similar production rates. A preliminary safety evaluation shows that an incredible worst case accident could be contained and the maximum off-site dose would be well below accident protective action guidance levels

Global characteristics of an ATON stationary plasma thruster operating with krypton and xenon

International Nuclear Information System (INIS)

Bugrova, A.I.; Lipatov, A.S.; Solomatina, L.V.; Morozov, A.I.

2002-01-01

Paper contains the experimental results of operation of the ATON plasma thruster operating with krypton and xenon. It is shown that consumption of a working gas for consumption of a working gas the krypton base thrust is higher in contrast to xenon base one at lower efficiency. In case of krypton use one obtained the efficiency constituting ∼ 60% at specific pulse reaching 3000 s. Jet divergence in case of krypton use is ∼ ± 22 deg in contrast to ∼ ± 11 deg in case of xenon use [ru

A review of ''The potential effects of release of krypton-85''

International Nuclear Information System (INIS)

Saunders, C.P.R.

1993-06-01

A Report into the potential effects of the release of Krypton-85 from the Thermal Oxide Reprocessing Plant (THORP) at Sellafield, was commissioned by British Nuclear Fuels Ltd. The report dealt with the atmospheric impact of the release of Krypton-85 and considered specifically the areas of atmospheric electricity, ionisation, aerosols and conductivity, in terms of the releases of Krypton-85 from THORP. This present review has three objectives: to consider the atmospheric effects of the proposed discharges from THORP, to comment upon the magnitude of the postulated effects from Krypton-85 discharges compared with those from other sources of radioactivity in the atmosphere, and, to comment on the conclusions drawn by the authors of the report. This review was conducted under the aegis of the United Kingdom Inspectorate of Pollution. (author)

Separation of radioactive krypton from carbon dioxide and oxygen with molecular sieves

International Nuclear Information System (INIS)

Forsberg, C.W.

1977-10-01

In the reprocessing of HTGR nuclear fuels, the off-gas cleanup system generates a stream containing about 1 percent krypton, 90+ percent CO 2 , and various amounts of O 2 , N 2 , and xenon. The krypton is radioactive and must be separated from the CO 2 before it is bottled or zeolite-encapsulated for final disposal. A series of theoretical and experimental investigations to find the best method for separating CO 2 and krypton under the required conditions showed that 5A molecular sieves near O 0 C and 1.01 x 10 5 Pa (1 atm) provided the most effective separation. Molecular sieves are powerful solid adsorbents for CO 2 but weak adsorbents for krypton. For a typical expected CO 2 -O 2 -krytpon gas mixture, a molecular sieve bed adsorbs the CO 2 , allows the O 2 to pass freely through the bed, and concentrates the krypton before it exits the bed. The process selected and investigated is called frontal analysis gas chromatography

Krypton calibration of time projection chambers of the NA61/SHINE experiment

CERN Document Server

Naskret, Michal

The NA61/SHINE experiment at CERN is searching for the critical point in phase transition between quark-gluon plasma and hadronic matter. To do so we use the most precise apparatus - Time Projection Chamber. Its main task is to find trajectories of particles created in a relativistic collision. In order to improve efficiency of TPCs, we introduce calibration using radioactive krypton gas. Simulation of events in a TPC cham- ber through a decay of excited krypton atoms gives us a spectrum, which is later fitted to the model spectrum of krypton from a Monte-Carlo simulation. The data obtained in such a way serves us to determine malfunctioning electronics in TPCs. Thanks to the krypton calibration we can create a map of pad by pad gains. In this thesis I will de- scribe in detail the NA61 experimental setup, krypton calibration procedure, calibration algorithm and results for recent calibration runs

Observation of clinical effect of krypton laser in the treatment of diabetic retinopathy with non-proliferative%多波长氪激光光凝治疗非增殖期糖尿病视网膜病变临床疗效观察

Institute of Scientific and Technical Information of China (English)

韩凤芹; 刘守丽

2014-01-01

Objective:To observe the clinical effect of krypton laser in the treatment of diabetic retinopathy with non-proliferative. Methods:54 patients(104 eyes) of diabetic retinopathy with non-proliferative were treated with krypton laser,and the clinical effect was observed.Results:78 eyes(75%)had visual acuity improved and 20 eyes(19.2%)had no change in visual acuity,with 6 eyes(6%) having visual acuity decreased.96 eyes had retinal neovascularization,non perfusion area and macular edema and partial regression and 4 eyes were invalid,with 4 eyes macular edema worse.Conclusion:The effect of krypton laser photocoagulation in the treatment of diabetic retinopathy with non-proliferative is significantly.%目的：观察多波长氪激光光凝治疗非增殖期糖尿病视网膜病变的临床疗效。方法：2012年5月-2013年12月收治采用多波长氪激光治疗的非增殖期糖尿病视网膜病变患者54例(104眼)，观察治疗效果。结果：视力提高78眼(75%)，视力无变化20眼(19.2%)，视力下降6眼(6%)。视网膜血管新生、无灌注区和黄斑水肿消退及部分消退96眼，治疗无效4眼，黄斑水肿恶化4眼。结论：多波长氪激光治疗糖尿病视网膜病变增殖期疗效显著。

Carbon dioxide-krypton separation and radon removal from nuclear-fuel-reprocessing off-gas streams

International Nuclear Information System (INIS)

Hirsch, P.M.; Higuchi, K.Y.; Abraham, L.

1982-07-01

General Atomic Company (GA) is conducting pilot-plant-scale tests that simulate the treatment of radioactive and other noxious volatile and gaseous constituents of off-gas streams from nuclear reprocessing plants. This paper reports the results of engineering-scale tests performed on the CO 2 /krypton separation and radon holdup/decay subsystems of the GA integrated off-gas treatment system. Separation of CO 2 from krypton-containing gas streams is necessary to facilitate subsequent waste processing and krypton storage. Molecular sieve 5A achieved this separation in dissolver off-gas streams containing relatively low krypton and CO 2 concentrations and in krypton-rich product streams from processes such as the krypton absorption in liquid carbon dioxide (KALC) process. The CO 2 /krypton separation unit is a 30.5-cm-diameter x 1.8-m-long column containing molecular sieve 5A. The loading capacity for CO 2 was determined for gas mixtures containing 250 ppM to 2.2% CO 2 and 170 to 750 ppM krypton in either N 2 or air. Gas streams rich in CO 2 were diluted with N 2 to reduce the temperature rise from the heat of adsorption, which would otherwise affect loading capacity. The effluent CO 2 concentration prior to breakthrough was less than 10 ppM, and the adsorption capacity for krypton was negligible. Krypton was monitored on-line with a time-of-flight mass spectrometer and its concentration determined quantitatively by a method of continuous analysis, i.e., selected-ion monitoring. Radon-220 was treated by holdup and decay on a column of synthetic H-mordenite. The Rn-220 concentration was monitored on-line with flow-through diffused-junction alpha detectors. Single-channel analyzers were utilized to isolate the 6.287-MeV alpha energy band characteristic of Rn-220 decay from energy bands due to daughter products

Efficacy observation on multiple wave length laser for diabetic retinopathy and central retinal vein occlusion

Directory of Open Access Journals (Sweden)

Tao Tian

2014-07-01

Full Text Available AIM:To observe the efficacy of the multiple wave length laser in treating diabetic retinopathy combined with central retinal vein occlusion. METHODS:Totally 95 cases(100 eyeswith diabetic retinopathy combined with central retinal vein occlusion were treated by multiple wave length laser. Krypton yellow laser was used for macular edema in focal photocoagulation and diffuse photocoagulation. For peripheral retina, krypton green or krypton red laser were used. Visual acuity, slit-lamp biomicroscopy, ophthalmoscopy and fundus fluorescein angiography were performed preoperatively and postoperatively. The patients were followed up for 12 to 48wk. In this study, change in visual acuity and macular edema were observed in both groups, and statistical analysis was performed. RESULTS:The effective rate was 61.2% in diffuse macular edema group and 86.3% in focal macular edema group. The general effective rate of later was higher than the former, while the treatment effect had significant statistical difference(PCONCLUSION: Multiple wave length laser is an effective and safe way to treat diabetic macular edema of diabetic retinopathy combined with central retinal vein occlusion,which is worth widely applying in clinical practice.

The Liquid Krypton Calorimeter Cryogenics for the NA48 Experiment

CERN Document Server

Bremer, J; Dauvergne, J P; Gonidec, A; Kesseler, G; Kubischta, Werner; Linser, G; Schinzel, D; Taureg, Hans; Wertelaers, Piet

1998-01-01

The NA48 cryogenic system has to provide stable thermal conditions (120 K) in a 9000 liter liquid krypton calorimeter, and has to ensure safe and loss free storage of the liquid during idle periods. Direct cooling of the krypton by nitrogen is used in emergency cases, while an intermediate cooler, containing saturated liquid argon at around 10 bar (117 K) is used under normal operation conditions when high thermal stability is needed. The krypton pressure is, during data taking, regulated to a value of (1.05 ± 0.01) bar for a period of about 8 months of continuous operation of the calorimeter.

Climate aspects of radioactive trace gases, especially krypton-85

International Nuclear Information System (INIS)

Kollert, R.; Butzin, M.

1990-01-01

The amount of krypton 85 currently present in the atmosphere is 3.300 Peta Bq. This atmospheric krypton contamination stems from atom bomb tests of the past and from nuclear power plants as well as spent fuel reprocessing plants. The paper investigates the air-electric and air-chemical impact of Kr-85 on the atmosphere and makes a forecast of the future Kr-85 contamination. (DG) [de

Effect of fluoride content on ion release from cast and selective laser melting-processed Co-Cr-Mo alloys.

Science.gov (United States)

Yang, Xu; Xiang, Nan; Wei, Bin

2014-11-01

Selective laser melting (SLM) alloy is gaining popularity in prosthetic dentistry. However, its biocompatibility has been of some concern because of long-term exposure to fluoride in the oral environment. The purpose of this study was to examine the effect of fluoride concentration on ion release from Co-Cr-Mo alloy specimens fabricated using either SLM or lost-wax casting when immersed in an artificial saliva solution containing fluoride. Specimens were prepared with either a SLM system for the SLM alloy or conventional lost-wax techniques for the cast alloy. The specimen surfaces were wet ground with silicon carbide paper (400, 800, and 1200 grit) and immersed in modified artificial saliva solutions, the pH of which had been adjusted to 5.0 with lactic acid and which contained NaF at concentrations of 0.00%, 0.05%, 0.1%, or 0.2%. The metal ion content of the solution was determined with an inductively coupled plasma mass spectrometer. The results were submitted to 2-way ANOVA and regression analysis (α=.05). Fluoride concentration significantly influenced the elemental ion release from both the SLM and cast alloys. The quantity of ions released increased significantly with increasing fluoride concentration. The ion release from the cast specimens was significantly greater than that from the SLM specimens. The performance of the SLM alloy in immersion tests demonstrates that this new technique is a superior choice because of its good biocompatibility. Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Krypton-85 enrichment by adsorption-desorption process

International Nuclear Information System (INIS)

Khan, A.A.; Deshingkar, D.S.; Ramarathinam, K.

1975-01-01

The use of activated charcoal columns in conjunction with cryogenic distillation system for concentration of krypton-85 in fuel reprocessing process off-gas stream is reported. Dynamic adsorption of krypton on activated charcoals and its subsequent desorption by applying vacuum were studied. The possible reduction in the quantity of carrier gas to be liquified in the cryogenic system by utilising this process has been discussed on the basis of results of laboratory evaluations. The possibility of elimination of air and oxygen to avoid explosion hazards associated with radiolytic formation and concentration of ozone has also been considered. (author)

Commercializing potassium terbium fluoride, KTF (KTb3F10) faraday crystals for high laser power optical isolator applications

Science.gov (United States)

Schlichting, Wolfgang; Stevens, Kevin; Foundos, Greg; Payne, Alexis

2017-10-01

Many scientific lasers and increasingly industrial laser systems operate in manufacture. However, for high-power laser applications TGG is limited by its absorption at 1064nm and its thermo-optic coefficient, dn/dT. Specifically, thermal lensing and depolarization effects become a limiting factor at high laser powers. While TGG absorption has improved significantly over the past few years, there is an intrinsic limit. Now, SYNOPTICS is commercializing the enhanced new crystal Potassium Terbium Fluoride KTF (KTb3F10) that exhibits much smaller nonlinear refractive index and thermo-optic coefficients, and still exhibits a Verdet constant near that of TGG. This cubic crystal has relatively low absorption and thermo-optic coefficients. It is now fully characterized and available for select production orders. At OPTIFAB in October 2017 we present recent results comparing the performance of KTF to TGG in optical isolators and show SYNOPTICS advances in large volume crystal growth and the production ramp up.

Development and characterization of femtosecond laser driven soft x-ray lasers

International Nuclear Information System (INIS)

Bettaibi, I.

2005-06-01

Coherent soft x-ray sources have an important potential for scientific, medical and industrial applications. The development of high intensity laser systems allowed the realization of new coherent and fast soft x-ray sources like high order harmonic generation and soft x-ray lasers. These sources are compact, cheaper than traditional sources such as synchrotrons, and are thus interesting. This thesis presents the study of a new soft x-ray laser pumped by a femto-second laser beam working at 10 Hz. The circularly polarized ultra intense laser is longitudinally focused in a cell filled with xenon or krypton, to obtain the amplification of two lasing lines at 41.8 nm and 32.8 nm in Pd-like xenon and Ni-like krypton respectively. We carry out an experimental and numerical study of the source to understand the importance of different parameters such as the laser intensity and polarization, the gas pressure and the cell length. We have also spatially and temporally characterized the soft x-ray laser beam. To compensate the refraction of the driving laser we have investigated guiding techniques consisting in creating a plasma channel by electric discharge or using the multiple reflections of the driving laser on the internal walls of the dielectric tubes of sapphire or glass. A spectacular improvement of the source performances has been observed in both cases. Finally, we present a preliminary study on a different x-ray scheme: the inner shell photo pumping of neutral atoms. We have developed an optical system, which should create the appropriate conditions for the realisation of short wavelength x-ray amplifier. (author)

10 CFR 30.19 - Self-luminous products containing tritium, krypton-85, or promethium-147.

Science.gov (United States)

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false Self-luminous products containing tritium, krypton-85, or..., krypton-85, or promethium-147. (a) Except for persons who manufacture, process, produce, or initially transfer for sale or distribution self-luminous products containing tritium, krypton-85, or promethium-147...

Krypton-81 dating of old groundwater. Chapter 5

International Nuclear Information System (INIS)

Purtschert, R.; Yokochi, R.; Sturchio, N.C.

2013-01-01

The abundance of krypton in the atmosphere has been quoted for nearly half a century as 1.14 ± 0.01 ppm, which corresponds to a total atmospheric inventory of 4.51 × 10 12 m 3 STP (Verniani (1966) [243]). A recent re-evaluation yielded a value of 1.099 ± 0.009 ppmv, which is about 4% lower than the previously used value (Aoki and M akide (2005) [244]). Krypton has six stable isotopes of which 84 Kr is the most abundant, comprising about 57% of natural Kr (Table 5.1). Eleven major radioactive isotopes of Krexist but only 81 Kr and 85 Kr, with halflives of 229 000 and 10.76 a, respectively, exceed 2 d and are, therefore, suitable for the investigation of environmental processes. Krypton-81 is produced in the atmosphere by cosmic ray induced spallation of heavier stable Krisotopes and by the nuclear reactions 80 Kr(n, γ) 81 Kr and 82 Kr(γ, n) 81 Kr.

Krypton based adsorption type cryogenic refrigerator

Science.gov (United States)

Jones, Jack A. (Inventor); Schember, Helene R. (Inventor)

1989-01-01

Krypton and a monolithic porous carbon such as Saran carbon are used respectively as the sorbate and sorbent of an adsorption type refrigerator to improve refrigeration efficiency and operational longevity.

Laser microsampling method for determination of retained fission gas in irradiated nuclear fuels

International Nuclear Information System (INIS)

Graczyk, D.G.; Bandyopadhyay, G.; Gehl, S.M.; Hughes, J.P.; Goodspeed, H.T.

1979-10-01

A small ruby laser adapted to fire through a microscope is used to release fission gases from specific sites on a plane surface of an irradiated fuel specimen. Interaction of the focused laser pulse with the specimen surface results in a conical crater from which sampled material has been vaporized; the crater is surrounded by a heat-affected zone in which intergranular fracture and grain separation allow release of grain-boundary gases. Procedures for measuring the amount of krypton-85 released by laser heating and the volume of material from which the release occurred are presented. The data obtained may be used to obtain local krypton fission-gas concentrations and the intragranular/intergranular distribution

Nike Facility Diagnostics and Data Acquisition System

Science.gov (United States)

Chan, Yung; Aglitskiy, Yefim; Karasik, Max; Kehne, David; Obenschain, Steve; Oh, Jaechul; Serlin, Victor; Weaver, Jim

2013-10-01

The Nike laser-target facility is a 56-beam krypton fluoride system that can deliver 2 to 3 kJ of laser energy at 248 nm onto targets inside a two meter diameter vacuum chamber. Nike is used to study physics and technology issues related to laser direct-drive ICF fusion, including hydrodynamic and laser-plasma instabilities, material behavior at extreme pressures, and optical and x-ray diagnostics for laser-heated targets. A suite of laser and target diagnostics are fielded on the Nike facility, including high-speed, high-resolution x-ray and visible imaging cameras, spectrometers and photo-detectors. A centrally-controlled, distributed computerized data acquisition system provides robust data management and near real-time analysis feedback capability during target shots. Work supported by DOE/NNSA.

Operation and technology development of the radioactive xenon and krypton detection equipment

International Nuclear Information System (INIS)

Lee, Wanno; Choi, Sangdo; Ji, Youngyong; Lim, Jong Myoung; Cho, Young Hyun; Kang, Han Beul; Lee, Hoon; Kang, Moon Ja; Choi, Kun Sik

2013-03-01

Operation and technology development of the radioactive xenon and krypton detection equipment - Advancement, independence of operation technology for BfS-IAR system(the simultaneous analysis of xenon and krypton) installed after North Korea nuclear tests in 2006 and establishment of background base-line for xenon and krypton radioactivity. - Enhanced detection and analysis capabilities for neighborhood nuclear activities through advanced research of noble gas detection technology. Results of the Project · The operation of xenon and krypton analysis system (BfS-IAR) · Operation of fixed adsorption system. · Operation of portable adsorption system · Exercise of emergency response and proficiency test with SAUNA. · Measurement of noble gas background at specific region in Korea. - Radioxenon levels at Dongdu Cheon is approximately 1.6 mBq/m 3 · Development of automation filling system for absorber cooling

Efficient electron beam deposition for repetitively pulsed krypton fluoride lasers

International Nuclear Information System (INIS)

Hegeler, F.; Myers, M.C.; Friedman, M.; Sethian, J.D.; Swanekamp, S.B.; Rose, D.V.; Welch, D.R.

2002-01-01

We have demonstrated that we can significantly increase the electron beam transmission efficiency through a pressure foil structure (hibachi) by segmenting the beam into strips to miss the hibachi support ribs. In order to increase the electron beam transmission, the cathode strips are adjusted to compensate for beam rotation and pinching. The beam propagation through the hibachi has been both measured and simulated with 1-D and 3-D codes

THE RETENTION OF KRYPTON IN POLYCRYSTALLINE SILICON DURING HIGH-TEMPERATURE ANNEALING

NARCIS (Netherlands)

GREUTER, MJW; NIESEN, L; VANVEEN, A; EVANS, JH

1994-01-01

In a study into the annealing behaviour of silicon containing a few atomic per cent of krypton, it was found that, even at 0.87 of the silicon melting temperature, approximately 90% of the original krypton was still present. This result is compared with analogous work on metals where copious inert

Ultrafast quantum control of ionization dynamics in krypton.

Science.gov (United States)

Hütten, Konrad; Mittermair, Michael; Stock, Sebastian O; Beerwerth, Randolf; Shirvanyan, Vahe; Riemensberger, Johann; Duensing, Andreas; Heider, Rupert; Wagner, Martin S; Guggenmos, Alexander; Fritzsche, Stephan; Kabachnik, Nikolay M; Kienberger, Reinhard; Bernhardt, Birgitta

2018-02-19

Ultrafast spectroscopy with attosecond resolution has enabled the real time observation of ultrafast electron dynamics in atoms, molecules and solids. These experiments employ attosecond pulses or pulse trains and explore dynamical processes in a pump-probe scheme that is selectively sensitive to electronic state of matter via photoelectron or XUV absorption spectroscopy or that includes changes of the ionic state detected via photo-ion mass spectrometry. Here, we demonstrate how the implementation of combined photo-ion and absorption spectroscopy with attosecond resolution enables tracking the complex multidimensional excitation and decay cascade of an Auger auto-ionization process of a few femtoseconds in highly excited krypton. In tandem with theory, our study reveals the role of intermediate electronic states in the formation of multiply charged ions. Amplitude tuning of a dressing laser field addresses different groups of decay channels and allows exerting temporal and quantitative control over the ionization dynamics in rare gas atoms.

Krypton Adsorption on Zeolite-Templated Carbon and Anomalous Surface Thermodynamics.

Science.gov (United States)

Murialdo, Maxwell; Stadie, Nicholas P; Ahn, Channing C; Fultz, Brent

2015-07-28

Krypton adsorption was measured at eight temperatures between 253 and 433 K on a zeolite-templated carbon and two commercial carbons. The data were fitted using a generalized Langmuir isotherm model and thermodynamic properties were extracted. Differing from that on commercial carbons, krypton adsorption on the zeolite-templated carbon is accompanied by an increasing isosteric enthalpy of adsorption, rising by up to 1.4 kJ mol(-1) as a function of coverage. This increase is a result of enhanced adsorbate-adsorbate interactions promoted by the ordered, nanostructured surface of the adsorbent. An assessment of the strength and nature of these adsorbate-adsorbate interactions is made by comparing the measured isosteric enthalpies of adsorption (and other thermodynamic quantities) to fundamental metrics of intermolecular interactions of krypton and other common gases.

Technical Note: Calibration device for the krypton hygrometer KH20

Directory of Open Access Journals (Sweden)

T. Foken

2012-08-01

Full Text Available A calibration device for krypton hygrometers (KH20, Campbell Scientific, Inc. with variable path length is presented. This unit allows for in-situ calibrations of the krypton hygrometer, which is typically not very stable over time, during measuring campaigns. It was constructed mainly for application at high altitudes and low temperatures, where further improvements are needed to the IR-hygrometers which are normally used. The changing path length requires that a changing concentration of the absorber be simulated. Because oxygen absorbs more strongly than water vapour, the calibration is made against oxygen and transferred to water vapour. The design of the calibration instrument is made as one unit containing a stepper motor system, PC and humidity sensor. For the calibration, it is necessary to install the krypton hygrometer on this unit.

Study of laser plasma emission from doped targets

Czech Academy of Sciences Publication Activity Database

Velardi, L.; Krása, Josef; Velyhan, Andriy; Nassisi, V.

2012-01-01

Roč. 83, č. 2 (2012), , "02B911-1"-"02B911-3" ISSN 0034-6748 R&D Projects: GA MŠk(CZ) 7E09092; GA MŠk(CZ) LC528 EU Projects: European Commission(XE) 228334 - LASERLAB-EUROPE Institutional research plan: CEZ:AV0Z10100523 Keywords : copper * excimer lasers * ion mobility * krypton compounds * laser ablation Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.602, year: 2012

Fluoride absorption: independence from plasma fluoride levels

International Nuclear Information System (INIS)

Whitford, G.M.; Williams, J.L.

1986-01-01

The concept that there are physiologic mechanisms to homeostatically regulate plasma fluoride concentrations has been supported by results in the literature suggesting an inverse relationship between plasma fluoride levels and the absorption of the ion from the gastrointestinal tract of the rat. The validity of the relationship was questioned because of possible problems in the experimental design. The present work used four different methods to evaluate the effect of plasma fluoride levels on the absorption of the ion in rats: (i) the percentage of the daily fluoride intake that was excreted in the urine; (ii) the concentration of fluoride in femur epiphyses; (iii) the net areas under the time-plasma fluoride concentration curves after intragastric fluoride doses; and (iv) the residual amounts or fluoride in the gastrointestinal tracts after the intragastric fluoride doses. None of these methods indicated that plasma fluoride levels influence the rate or the degree or fluoride absorption. It was concluded that, unless extremely high plasma fluoride levels are involved (pharmacologic or toxic doses), the absorption of the ion is independent of plasma levels. The results provide further evidence that plasma fluoride concentrations are not homeostatically regulated

Krypton and xenon in the atmosphere of Venus

Science.gov (United States)

Donahue, T. M.; Hoffman, J. H.; Hodges, R. R., Jr.

1981-01-01

The paper reports a determination by the Pioneer Venus large probe neutral mass spectrometer of upper limits to the concentration of krypton and xenon along with most of their isotopes in the atmosphere of Venus. The upper limit to the krypton mixing ratio is estimated at 47 ppb, with a very conservative estimate at 69 ppb. The probable upper limit to the sum of the mixing ratios of the isotopes Xe-128, Xe-129, Xe-130, Xe-131, and Xe-132 is 40 ppb by volume, with a very conservative upper limit three times this large.

Liquid Fluoride Salt Experimentation Using a Small Natural Circulation Cell

Energy Technology Data Exchange (ETDEWEB)

Yoder Jr, Graydon L [ORNL; Heatherly, Dennis Wayne [ORNL; Williams, David F [ORNL; Elkassabgi, Yousri M. [Texas A& M University, Kingsville; Caja, Joseph [Electrochemical Systems, Inc.; Caja, Mario [ORNL; Jordan, John [Texas A& M University, Kingsville; Salinas, Roberto [Texas A& M University, Kingsville

2014-04-01

A small molten fluoride salt experiment has been constructed and tested to develop experimental techniques for application in liquid fluoride salt systems. There were five major objectives in developing this test apparatus: Allow visual observation of the salt during testing (how can lighting be introduced, how can pictures be taken, what can be seen) Determine if IR photography can be used to examine components submerged in the salt Determine if the experimental configuration provides salt velocity sufficient for collection of corrosion data for future experimentation Determine if a laser Doppler velocimeter can be used to quantify salt velocities. Acquire natural circulation heat transfer data in fluoride salt at temperatures up to 700oC All of these objectives were successfully achieved during testing with the exception of the fourth: acquiring velocity data using the laser Doppler velocimeter. This paper describes the experiment and experimental techniques used, and presents data taken during natural circulation testing.

Preliminary safety evaluation of a commercial-scale krypton-85 encapsulation facility

International Nuclear Information System (INIS)

Christensen, A.B.; Tanner, J.E.; Knecht, D.A.

1980-09-01

This report demonstrates that a commercial-scale facility for encapsulating krypton-85 in zeolite-5A or glass at a 2000 MTHM per year nuclear fuel reprocessing plant can be designed to contain fragments and the 340 to 850 kCi krypton-85 inventory from an assumed catastrophic failure of the high pressure vessel. The vessel failure was assumed as a worst case and was not based on a detailed design evaluation or operating experience. The process design is based on existing commercial hot isostatic pressing technology operated at up to 40 times the scale required for krypton encapsulation. From the calculated process gas inventory in the pressure vessel and vessel design, the explosive energy of 8.4 kg TNT and vessel plug and fragment velocities were calculated. The facility Containment Cell housing the high pressure vessel was designed to contain the gases, fragments, and the shock wave energy calculated for vessel failure. The Access Cell located directly above the Containment Cell was designed to be a tertiary confinement of krypton-85, should the access hatch be breached

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...

Press forging and optical properties of lithium fluoride

Science.gov (United States)

Ready, J. F.; Vora, H.

1980-07-01

Lithium fluoride is an important candidate material for windows on high power, short-pulse ultraviolet and visible lasers. Lithium fluoride crystals were press forged in one step over the temperature range 300 to 600 C to obtain fine grained polycrystalline material with improved mechanical properties. The deformation that can be given to a lithium fluoride crystal during forging is limited by the formation of internal cloudiness (veiling) with the deformation limit increasing with increasing forging temperature from about 40 percent at 400 C to 65 percent at 600 C. To suppress veiling, lithium fluoride crystals were forged in two steps over the temperature range 300 to 600 C, to total deformations of 69 to 76 percent, with intermediate annealing at 700 C. This technique yields a material which has lower scattering with more homogeneous microstructure than that obtained in one step forging. The results of characterization of various optical and mechanical properties of single crystal and forged lithium fluoride, including scattering, optical homogeneity, residual absorption, damage thresholds, environmental stability, and thresholds for microyield are described.

Press forging and optical properties of lithium fluoride

International Nuclear Information System (INIS)

Ready, J.F.; Vora, H.

1979-01-01

Lithium fluoride is an important candidate material for windows on high-power, short-pulse ultraviolet and visible lasers. Lithium fluoride crystals have been press forged in one step over the temperature range 300 to 600 0 c to obtain fine-grained polycrystalline material with improved mechanical properties. The deformation that can be given to a lithium fluoride crystal during forging is limited by the formation of internal cloudiness (veiling) with the deformation limit increasing with increasing forging temperature from about 40% at 400 0 C to 65% at 600 0 C. To suppress veiling, lithium fluoride crystals were forged in two steps over the temperature range 300 to 600 0 C, to total deformations of 69-76%, with intermediate annealing at 700 0 C. This technique yields a material which has lower scattering with more homogeneous microstructure than that obtained in one-step forging. The results of characterization of various optical and mechanical properties of single-crystal and forged lithium fluoride, including scattering, optical homogeneity, residual absorption, damage thresholds, environmental stability, and thresholds for microyield are described

Advances on Polymer Optical Fiber Gratings Using a KrF Pulsed Laser System Operating at 248 nm

Directory of Open Access Journals (Sweden)

Carlos A. F. Marques

2018-03-01

Full Text Available This paper presents the achievements and progress made on the polymer optical fiber (POF gratings inscription in different types of Fiber Bragg Gratings (FBGs and long period gratings (LPGs. Since the first demonstration of POFBGs in 1999, significant progress has been made where the inscription times that were higher than 1 h have been reduced to 15 ns with the application of the krypton fluoride (KrF pulsed laser operating at 248 nm and thermal treatments such as the pre-annealing of fibers. In addition, the application of dopants such as benzyl dimethyl ketal (BDK has provided a significant decrease of the fiber inscription time. Furthermore, such improvements lead to the possibility of inscribing POF gratings in 850 nm and 600 nm, instead of only the 1550 nm region. The progress on the inscription of different types of polymer optical fiber Bragg gratings (POFBGs such as chirped POFBGs and phase-shifted POFBGs are also reported in this review.

Photolysis of phosphodiester bonds in plasmid DNA by high intensity UV laser irradiation

International Nuclear Information System (INIS)

Croke, D.T.; Blau, Werner; OhUigin, Colm; Kelly, J.M.; McConnell, D.J.

1988-01-01

The cleavage of phosphodiester bonds in DNA exposed to high intensity UV laser pulses in aerated aqueous solution has been investigated using a krypton fluoride excimer laser (248 nm) and bacterial plasmid DNA. The dependence of strand breakage on fluence and intensity has been studied in detail and shows that the process is non-linear with respect to intensity. The relationship between the quantum yield for strand breakage and intensity shows that the strand breakage reaction involves two-photon excitation of DNA bases. The quantum yield rises with intensity from a lower value of 7 x 10 -5 until a maximum value of 4.5 x 10 -4 is attained at intensities of 10 11 W m -2 and above. This value is approximately fifty-fold higher than the quantum yield for strand breakage induced by exposure to low density UV irradiation (254 nm, 12 W m -2 ). DNA sequencing experiments have shown that strand breakage occurs by the specific cleavage of the phosphodiester bond which lies immediately 3' to guanine residues in the DNA, leaving some alkali-labile remnant attached to the terminal phosphate. A mechanism for DNA strand breakage which involves the generation of guanine radical cations is proposed. (author)

Phase-shifted Bragg grating inscription in PMMA microstructured POF using 248 nm UV radiation

OpenAIRE

Pereira, L.; Pospori, A.; Antunes, Paulo; Domingues, Maria Fatima; Marques, S.; Bang, Ole; Webb, David J.; Marques, Carlos A.F.

2017-01-01

In this work we experimentally validate and characterize the first phase-shifted polymer optical fiber Bragg gratings (PS-POFBGs) produced using a single pulse from a 248 nm krypton fluoride laser. A single-mode poly (methyl methacrylate) optical fiber with a core doped with benzyl dimethyl ketal for photosensitivity improvement was used. A uniform phase mask customized for 850 nm grating inscription was used to inscribe these Bragg structures. The phase shift defect was created directly duri...

Accurate ab initio potential for the krypton dimer and transport properties of the low-density krypton gas.

Science.gov (United States)

Waldrop, Jonathan M; Song, Bo; Patkowski, Konrad; Wang, Xiaopo

2015-05-28

A new highly accurate potential energy curve for the krypton dimer was constructed using coupled-cluster calculations up to the singles, doubles, triples, and perturbative quadruples level, including corrections for core-core and core-valence correlation and for relativistic effects. The ab initio data points were fitted to an analytic potential which was used to compute the most important transport properties of the krypton gas. The viscosity, thermal conductivity, self-diffusion coefficient, and thermal diffusion factor were calculated by the kinetic theory at low density and temperatures from 116 to 5000 K. The comparisons with literature experimental data as well as with values from other pair potentials indicate that our new potential is superior to all previous ones. The transport property values computed in this work are recommended as standard values over the complete temperature range.

Solubility of krypton in liquid CO2

International Nuclear Information System (INIS)

Notz, K.J.; Meservey, A.B.

1976-06-01

The solubility of krypton in liquid CO 2 was measured experimentally over essentially the entire liquid range of CO 2 , from -53 to 29 0 C. A tracer technique using 85 Kr was employed, and equilibrated gas-liquid samples were analyzed in situ with a collimated counter. Dilute concentrations of krypton were used, and the data are expressed as a distribution ratio, Y/sub Kr//X/sub Kr/, the log of which is nearly linear with respect to temperature from the lowest temperature to about 20 0 C, above which the values fall off rapidly toward a value of unity at the critical temperature. The numerical values obtained for the distribution ratio increase from 1.44 at 29 0 C to 29.4 at -53 0 C

Immobilization of krypton in a metal matrix

International Nuclear Information System (INIS)

Whitmell, D.S.

1987-01-01

The report presents the work carried out on the immobilization of krypton in a metallic matrix by combined ion implantation and sputtering. The process has been successfully tested using 100 curies of fully active krypton in order to demonstrate that the process operates in the radiation levels which will be obtained with active gas at a reprocessing plant. A design study for a plant for fuel reprocessing has shown that the process can be simply operated, without requiring shielded cells. These results, which complete the development programme, indicate that the process is ideal for the containment of kripton arising from the processing of nuclear fuel and that the product will retain the gas under normal storage conditions and also during simulated accident conditions

Occlusion and storage of krypton in solids

International Nuclear Information System (INIS)

Vansant, E.F.; Thijs, A.; Peeters, G.; Bievre, P. de; Verhaert, I.

1984-01-01

The modification process in order to change in a controlled way the effective pore size of zeolites was optimized by investigating the reaction conditions such as degree of chemisorption, reaction temperature, extent of primary/secondary reactions, type of modifying agent, type of substrate, etc. Different reaction and adsorption conditions have been tested to increase the thermal stability of encapsulated krypton in modified zeolites. The possibilities for zeolite modification have been enlarged by combining boranation and silanation with a thermal treatment of sepiolite, and by the formation of boron-nitrogen compounds in zeolites. Screening experiments, on a semi-industrial scale, of the krypton removal from air were carried out. Two kinds of Kr/air separation have been tested suscessfully on modified mordenite

Relativistic Multichannel Treatment of Krypton Spectra across the First Ionization Threshold

Institute of Scientific and Technical Information of China (English)

QU Yi-Zhi; PENG Yong-Lun

2005-01-01

@@ The relativistic multichannel theory has been extended to calculate both the eigen quantum defects μα, transformation matrix Uiα, and the eigen dipole matrix elements Dα of krypton. The Rydberg and autoionizationspectra of krypton across the first ionization threshold are calculated within the framework of multichannel quantum defect theory. Our calculated spectra are in agreement with the absolute measurement data.

Calcium fluoride

International Nuclear Information System (INIS)

King, C.W.; Nestor, O.H.

1989-01-01

A new process for producing large, single, oriented crystals of calcium fluoride (CaF 2 ) has been developed which overcomes the limitations of current growing methods. This process has been reduced to practice and has yielded oriented crystals 17.5 x 17.5 x 5 cm 3 . Currently nearing completion is a system for producing 35 x 35 x 7.5 cm 3 single crystals. A scale up to one-meter-square is considered feasible. This crystal growing process makes possible the fabrication of very large CaF 2 windows. Suitability for very high power lasers, however, requires attention to properties beyond mere size. A process to generate higher purity growth stock (starting material) was also developed. The additional purification of the growth stock contributes to lower bulk absorption, the absence of color centers and increased radiation hardness. Also identified were several specific impurities which correlate with radiation hardness. A correlation was found between color centers induced by laser radiation and ionizing radiation. Other CaF 2 crystal properties such as tensile strength, absorption and laser damage thresholds were studied and are discussed

The combined use of Er,Cr:YSGG laser and fluoride to prevent root dentin demineralization

Directory of Open Access Journals (Sweden)

Vinícius Rangel GERALDO-MARTINS

2014-10-01

Full Text Available The use of erbium lasers to prevent caries in enamel has shown positive results. However, it is not known if Er,Cr:YSGG laser can also be used to increase acid resistance of root dentine, which is another dental tissue susceptible to the action of cariogenic bacteria. Objective: To analyze the effects of the Er,Cr:YSGG laser (λ=2.78 μm, 20 Hz irradiation associated with 2% neutral sodium fluoride (NaF to prevent root dentin demineralization. Material and Methods: One hundred human root dentin samples were divided into 10 groups (G and treated as follows: G1: no treatment; G2: NaF; G3: laser (4.64 J/cm2 with water cooling (WC=5.4 mL/min; G4: laser (4.64 J/cm2 without WC; G5: laser (8.92 J/cm2 with WC; G6: laser (8.92 J/cm2 without WC; G7: laser (4.64 J/cm2 with WC and NaF; G8: laser (4.64 J/cm2 without WC and NaF; G9: laser (8.92 J/cm2 with WC and NaF; G10: laser (8.92 J/cm2 without WC and NaF. The NaF gel was applied alone or after 4 min of irradiation. After 14 days of acid challenge, the samples were sectioned and the Knoop microhardness (KHN test was done at different depths (30, 60, 90 and 120 μm from the outer dentin surface. Data were analyzed by one-way ANOVA and Fisher’s test (α=5%. Results: The results showed that G8 and G10 presented higher KHN than the G1 for the depths of 30 and 60 μm, indicating an increase of the acid resistance of the dentin in up to 35% (p<0.05. Conclusions: The use of Er,Cr:YSGG laser irradiation at 4.64 J/ cm2 and 8.92 J/cm2 without water cooling and associated with 2% NaF can increase the acid resistance of human root dentin.

Trapping of deuterium in krypton-implanted nickel

International Nuclear Information System (INIS)

Frank, R.C.; McManus, S.P.; Rehn, L.E.; Baldo, P.

1986-01-01

Krypton ions with energy 600 keV were implanted in nickel to fluences of 2 x 10 16 cm -2 under three different conditions. Deuterium was subsequently introduced into the implanted regions by electrolysis at room temperature. After the diffusible deuterium was permitted to escape, the 2 H( 3 He, 1 H) 4 He nuclear reaction was used to analyze for the trapped deuterium during an isochronal annealing program. The region implanted at 100 0 C with no higher temperature anneal had the largest number of traps; the region implanted at 100 0 C and annealed for 100 min at 500 0 C had considerably less; the region implanted at 500 0 C had the least. Electron diffraction patterns confirmed the existence of solid crystalline krypton in all three regions. Transmission electron microscope studies revealed precipitates with an average diameter of 8 nm in the region implanted at 500 0 C. The two regions implanted at 100 0 C contained smaller precipitates. Trap binding enthalpies were obtained by math modeling. In addition to the traps with binding enthalpy of 0.55 eV reported earlier by other investigators for helium implanted in nickel, a smaller number of traps with binding enthalpies up to 0.83 eV were also found. The trapping of deuterium by various types of imperfections, including the solid krypton precipitates, is discussed

Electron acceleration by a radially polarized laser pulse during ionization of low density gases

Directory of Open Access Journals (Sweden)

Kunwar Pal Singh

2011-03-01

Full Text Available The acceleration of electrons by a radially polarized intense laser pulse has been studied. The axial electric field of the laser is responsible for electron acceleration. The axial electric field increases with decreasing laser spot size; however, the laser pulse gets defocused sooner for smaller values and the electrons do not experience high electric field for long, reducing the energy they can reach. The electron remains confined in the electric field of the laser for longer and the electron energy peaks for the normalized laser spot size nearly equal to the normalized laser intensity parameter. Electron energy peaks for initial laser phase ϕ_{0}=π due to accelerating laser phase and decreases with transverse initial position of the electrons. The energy and angle of the emittance spectrum of the electrons generated during ionization of krypton and argon at low densities have been obtained and a right choice of laser parameters has been suggested to obtain high energy quasimonoenergetic collimated electron beams. It has been found that argon is more suitable than krypton to obtain high energy electron beams due to higher ionization potential of inner shells for the former.

Preliminary safety evaluation of a commercial-scale krypton-85 encapsulation facility

International Nuclear Information System (INIS)

Christensen, A.B.; Tanner, J.E.; Knecht, D.A.

1980-01-01

This paper demonstrates that a commercial-scale facility for encapsulating krypton-85 in zeolite-5A or glass at a 2000 MTHM per year nuclear fuel reprocessing plant can be designed to contain fragments and the 340 to 850 kCi krypton-85 inventory from an assumed catastrophic failure of the high pressure vessel. The vessel failure was assumed as a worst case and was not based on a detailed design evaluation or operating experience. The process design is based on existing commercial hot isostatic pressing technology operated at up to 40 times the scale required for krypton encapsulation. From the calculated process gas inventory in the pressure vessel and vessel design, the maximum explosive energy of 8.4 kg TNT and resulting vessel plug and fragment velocities were calculated. The facility Containment Cell housing the high pressure vessel was designed to contain the gases, fragments, and the shock wave energy calculated for a hypothetical vessel failure. The Access Cell located directly above the Containment Cell was designed to be a tertiary confinement of krypton-85, should the access hatch be breached. 3 figures, 2 tables

Effects of control technology on the projected krypton-85 environmental inventory

International Nuclear Information System (INIS)

Oscarson, E.E.

1973-01-01

Growth projections for the USA nuclear power industry may be used to make projections of future radioactive material inventories available for potential release to the environment. Since krypton-85 is produced in reactors, the potential routes of release to the environment are at the reactors or the fuel reprocessing plants. The present generation of reactors and fuel reprocessing plants do not use any systems to limit the release of krypton-85 into the biosphere. Clean-up systems are currently being designed and could be introduced when necessary. The cumulative inventory of krypton-85 in the environment is dependent upon the time of introduction of these clean-up systems and their efficiencies, in addition to the total quantity produced. Annual and cumulative inventories of krypton-85 are projected to increase dramatically over the next 50 years. If controls are assumed to be initiated at various years, a series of graphs of different cumulative environmental inventories and the associated doses and health effects are drawn. Varying the year of introduction and the efficiency of these systems allows one to speculate as to the optimum time for control implementation

Fluoride varnish or fluoride mouth rinse?

DEFF Research Database (Denmark)

Keller, M K; Klausen, BJ; Twetman, S

2016-01-01

OBJECTIVE: In many Danish communities, school-based fluoride programs are offered to children with high caries risk in adjunct to tooth brushing. The purpose of this field trial was to compare the caries-preventive effectiveness of two different fluoride programs in 6-12 year olds. BASIC RESEARCH...... different schools were enrolled after informed consent and their class unit was randomly allocated to one of two fluoride programs. INTERVENTIONS: One group received a semi-annual fluoride varnish applications (FV) and the other group continued with an existing program with fluoride mouth rinses once per...... in caries development over two years among children participating in a school-based fluoride varnish or mouth rinse program....

Auger measurements on the two-dimensional adsorption of krypton on graphite

International Nuclear Information System (INIS)

Kramer, H.M.; Suzanne, J.

1975-01-01

The adsorption of krypton on a (0001) plane of graphite was studied by means of Auger Electron Spectroscopy. The spectrum of krypton in the energy range from 5eV to 11eV and from 30eV to 70eV is reported. By means of LEED a √3x√3 superstructure is found for the adsorbed monolayer of Kr [fr

Pulsed chemical laser

International Nuclear Information System (INIS)

Jacobson, T.V.; Kimbell, G.H.

1975-01-01

A hydrogen fluoride laser capable of operating super radiantly and at atmospheric pressure is described. A transverse electrical discharge is utilized to energize the reaction of a hydrogen donor to provide hydrogen fluoride in a metastable energy state which reverts to a stable state by laser action. A large range of hydrogen and fluorine donors is disclosed. A preferred pair of donors is sulphur hexafluoride and propane. Helium is frequently added to the gas mix to act as a buffer. (U.S.)

Laser development for laser fusion applications research. Progress report, October 1977--March 1978

International Nuclear Information System (INIS)

1978-06-01

Research progress is reported on three laser programs being developed for the commercialization of laser-fusion energy. The lasers include iodine, hydrogen fluoride and Group VI atoms (e.g., O, S, Se, Te)

10 CFR 32.22 - Self-luminous products containing tritium, krypton-85 or promethium-147: Requirements for license...

Science.gov (United States)

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false Self-luminous products containing tritium, krypton-85 or... containing tritium, krypton-85 or promethium-147: Requirements for license to manufacture, process, produce... self-luminous products containing tritium, krypton-85, or promethium-147, or to initially transfer such...

Radiometric titration of officinal radiopharmaceuticals using radioactive kryptonates as end-point indicators. I

International Nuclear Information System (INIS)

Toelgyessy, J.; Dillinger, P.; Harangozo, M.; Jombik, J.

1980-01-01

A method for the determination of salicylic, acetylsalicylic and benzoic acids in officinal pharmaceutical based on radiometric titration with 0.1 mol.l -1 NaOH was developed. The end-point was detected with the aid of radioactive glass kryptonate. After the end-point, the excess titrant attacks the glass surface layers and this results in releasing 85 Kr, and consequently, in decreasing the radioactivity of the kryptonate employed. The radioactive kryptonate used as an indicator was prepared by the bombardment of glass with accelerated 85 Kr ions. The developed method is simple, accurate and correct. (author)

Extreme-ultraviolet wavelength and lifetime measurements in highly ionized krypton

CERN Document Server

Kukla, K W; Vogt, C M V; Berry, H G; Dunford, R W; Curtis, L J; Cheng, S

2005-01-01

We have studied the spectrum of highly ionized krypton in the extreme-ultraviolet wavelength region (50-300 Aa), using beam-foil excitation of fast krypton ions at the Argonne ATLAS accelerator facility. We report measurements of transition wavelengths and excited-state lifetimes for n=2 states in the lithiumlike, berylliumlike, and boronlike ions, Kr/sup 31+,32+,33+/. Excited state lifetimes ranging from 10 ps to 3 ns were measured by acquiring time- of-flight-delayed spectra with a position-sensitive multichannel detector.

Surface temperature measurement with radioactive kryptonates

International Nuclear Information System (INIS)

Pruzinec, J.; Piatrik, M.

1976-01-01

The preparation and use of radioactive kryptonates is described for measuring surface temperatures within the region of 45 to 70 degC. Two samples each were prepared of kryptonated beechwood and hydroquinone on a paper carrier. One sample served as the standard which during the experiment was placed in a thermostat at a constant temperature of 45 degC. The second sample was placed in another thermostat where the temperature changed from 45 to 70 degC. Both samples were in the thermostat for 30 mins. The temperature was raised in steps of 2.5 degC and the time of measurement was constant in both samples. The dependences are given of the drop in activity on temperature for both types of samples. The difference was determined of the drop in activity between the standard and the second sample and the relation for measuring the temperature of the sample was determined therefrom. (J.B.)

Liquid--vapor isotope fractionation factors in argon--krypton binary mixtures

International Nuclear Information System (INIS)

Lee, M.W.; Neufeld, P.; Bigeleisen, J.

1977-01-01

An equilibrium isotope effect has been studied as a continuous function of the potential field acting on the atom undergoing isotopic exchange. This has been accomplished through a study of the liquid vapor isotope fractionation factors for both, 36 Ar/ 40 Ar and 80 Kr/ 84 Kr in a series of binary mixtures which span the range between the pure components at 117.5 0 K. The 36 Ar/ 40 Ar fractionation factor increases (linearly) from (lnα)2.49 x 10 -3 in pure liquid argon to 2.91 x 10 -3 in an infinitely dilute solution in liquid krypton. Conversely, the 80 Kr/ 84 Kr fractionation factor decreases (linearly) from (lnα)0.98 x 10 -3 in pure liquid krypton to 0.64 x 10 -3 in an infinetely dilute solution in pure liquid argon. The mean force constants 2 U>/sub c/ on both argon and krypton atoms in the mixtures are derived from the respective isotope fractionation factors.The mean force constants for argon and krypton as a function of composition have been calculated by a modified corresponding states theory which uses the pure liquids as input parameters. The discrepancy is 8 percent at X/sub Ar/ + O. A systematic set of calculations has been made of 2 U> (Ar) and 2 U> (Kr) as a function of composition using radial distribution functions generated by the Weeks--Chandler--Anderson perturbation theory

An improved potential for krypton

International Nuclear Information System (INIS)

Aziz, R.A.

1979-01-01

An improved potential for krypton is presented. It has the simple but realistic form used by Aziz and Chen for argon based on the HFD potential suggested by Ahlrichs et.al. The potential, with known long-range behaviour, was fitted to second virial, viscosity and thermal conductivity data. The potential appears to have the best overall predictive ability for dilute gas, bulk and microscopic data. (author)

Device for separating and concentrating rare gases containing krypton gas

Energy Technology Data Exchange (ETDEWEB)

Kimura, S; Sugimoto, K

1975-06-11

In orer to highly concentrate krypton by means of adsorption and desorption of activated carbon, in a device for continuously separating and concentrating rare gases containing krypton gas by means of adsorbing and desorbing operation of activated carbon, the device includes adsorbers arranged in parallel and more than two stages of adsorbers arranged in series with the first mentioned adsorbers with the amount of activated carbon filled successively reduced, and a cooling mechanism for cooling the adsorbers when adsorbed and a heating mechanism for heating the adsorbers when desorbed.

Kinetic studies following state-selective laser excitation

International Nuclear Information System (INIS)

Keto, J.W.

1991-01-01

During the past year, we have made measurements of state-to-state energy transfer cross sections and radiative lifetimes for Xe*(6p,6p',7p) and Kr*(5p) states in xenon and krypton buffer gases. These results are relevant to kinetic models of both excimer lasers and the infrared xenon laser; and they are a significant improvement in the precision of the known radiative lifetimes. 3 refs., 2 figs., 2 tabs

Experience gained in the cryodistillation unit for krypton removal

International Nuclear Information System (INIS)

Geens, L.; Collard, G.; Goossens, W.R.A.; Vaesen, P.J.

1981-08-01

This unit with a nominal gas throughput of 8.5 g.s -1 has been used to investigate the removal of krypton from reprocessing off-gases under non-radioactive conditions. During the investigation a total operation time of more than 13.000 hours was reached with an average availability factor of 99.36%. The trapping efficiency for krypton was higher than 99.9%. The operation experience acquired indicates some critical aspects for the design of such a unit. The experimental results obtained allow to show the influence of feed pressure and temperature, reflux flow rate and noble gas concentrations on the performance of the unit. (author)

A study on relative populations and gain coefficients of neon-like krypton for fast moving plasma in capillary discharges

International Nuclear Information System (INIS)

Masnavi, M.; Kikuchi, T.; Nakajima, M.; Horioka, K.

2002-01-01

X-ray laser gains and the level populations for collisionally pumped neon (Ne)-like Krypton (KrXXVII) ions have been studied considering the 27 - levels of the 2s 2 2p 6 , 2s 2 2p 5 3s, 2s 2 2p 5 3p and 2s 2 2p 5 3d configurations. It was found that large gains on the 3p 1 S 0 → 3s 3 P 1 , 3p 3 D 2 → 3s 3 P 1 , and 3p 3 S 1 → 3s 1 P 1 transitions are formed for the electron density between 10 20 and 10 22 cm -3 at the electron temperatures 0.9,1 and 3 keV. The effect of the opacity of the 3d 1 P 1 - 2p 61 S 0 , 3d 3 D 1 - 2p 61 S 0 , 3d 3 P 1 - 2p 61 S 0 , 3s 3 P 1 - 2p 61 S 0 and 3s 1 P 1 - 2p 61 S 0 transitions are performed using the escape probability factor approximation, for both the static and dynamic plasmas, which include the effect of the large velocity gradient. In addition, we found some theoretical line-intensity ratios that are sensitive on the electron density, the electron temperature, and also opacity in the interest regime of Ne-like Krypton x-ray laser. (author)

Fluoride release from fluoride varnishes under acidic conditions.

Science.gov (United States)

Lippert, F

2014-01-01

The aim was to investigate the in vitro fluoride release from fluoride varnishes under acidic conditions. Poly(methyl methacrylate) blocks (Perspex, n=3 per group) were painted with 80 ± 5 mg fluoride varnish (n=10) and placed into artificial saliva for 30 min. Then, blocks were placed into either 1% citric acid (pH 2.27) or 0.3% citric acid (pH 3.75) solutions (n=3 per solution and varnish) for 30 min with the solutions being replaced every 5 min. Saliva and acid solutions were analyzed for fluoride content. Data were analyzed using three-way ANOVA (varnish, solution, time). The three-way interaction was significant (p>0.0001). Fluoride release and release patterns varied considerably between varnishes. Fluoride release in saliva varied by a factor of more than 10 between varnishes. Some varnishes (CavityShield, Nupro, ProFluorid, Vanish) showed higher fluoride release in saliva than during the first 5 min of acid exposure, whereas other varnishes (Acclean, Enamel-Pro, MI Varnish, Vella) showed the opposite behavior. There was little difference between acidic solutions. Fluoride release from fluoride varnishes varies considerably and also depends on the dissolution medium. Bearing in mind the limitations of laboratory research, the consumption of acidic drinks after fluoride varnish application should be avoided to optimize the benefit/risk ratio.

Fluoridated Water

Science.gov (United States)

... Genetics Services Directory Cancer Prevention Overview Research Fluoridated Water On This Page What is fluoride, and where is it found? What is water fluoridation? When did water fluoridation begin in the ...

Environmental consequences of atmosphereic krypton-85. Final report, January 1, 1977-September 30, 1979

International Nuclear Information System (INIS)

Boeck, W.L.

1979-01-01

Krypton-85 is a radioactive inert gas produced during normal operations of the nuclear fuel cycle. The quantities of krypton-85, that will be produced in the next century, are sufficient, if released, to alter the electrical state of the atmosphere. The principal hypothesis is that an anthropogenic alteration of the electric state of the atmosphere could alter other meterological phenomena and lead to significant environmental impacts. The goal of this project was to explore some areas of basic science related to the evaluation of that hypothesis. The approach was primarily theoretical. The following topics were addressed: a first approximation model to estimate the effects of krypton-85 on the electrical state of the atmosphere; an analysis of the pathways between krypton-85 production and the atmosphere; an analytical model for fair weather atmospheric electricity; and a dipole model for atmospheric electricity. The results will provide a framework on which detailed models can be built. The results should provide better understanding of some topics in atmospheric electricity

Barium fluoride surface preparation, analysis and UV reflective coatings at Lawrence Livermore National Laboratory

International Nuclear Information System (INIS)

Wuest, C.R.

1992-01-01

Lawrence Livermore National Laboratory (LLNL) has begun a program of study on barium fluoride scintillating crystals for the Barium Fluoride Electromagnetic Calorimeter Collaboration. This program has resulted in a number of significant improvements in the mechanical processing, polishing and coating of barium fluoride crystals. Techniques have been developed using diamond-loaded pitch lapping that can produce 15 angstrom RMS surface finishes over large areas. These lapped surfaces have been shown to be crystalline using Rutherford Back-scattering (RBS). Also, special polishing fixtures have been designed based on mounting technology developed for the 1.1 m diameter optics used in LLNL's Nova Laser. These fixtures allow as many as five 25--50 cm long barium fluoride crystals to be polished and lapped at a time with the necessary tolerances for the 16,000 crystal Barium Fluoride Calorimeter. In addition, results will be presented on coating barium fluoride with UV reflective layers of magnesium fluoride and aluminum

Contribution to the study of the structure of silver krypton solid solutions

International Nuclear Information System (INIS)

Levy, V.; Tullairet, J.; Delaplace, J.; Antolin-Baudier, J.; Adda, Y.

1964-01-01

The silver-krypton solid solutions formed by electrical discharge have been studied by X-rays, electrical resistivity and electronic transmission microscopy. The crystalline parameter and residual resistivity measurements have shown that the krypton atom behaves very differently to those of other elements of the periodic classification when dissolved in silver. The recovery of the crystalline parameter and of the electrical resistivity has been studied as a function of temperature. (authors) [fr

Neutron production with mixture of deuterium and krypton in Sahand Filippov type plasma focus facility

International Nuclear Information System (INIS)

Mohammadi, M.A.; Sobhanian, S.; Rawat, R.S.

2011-01-01

This Letter reports the order of magnitude enhancement in neutron yield from Sahand plasma focus device with krypton seeded deuterium operation. The highest average neutron yield of 2.2x10 9 neutrons per shot was achieved at 1.00 Torr deuterium with 3% krypton which is higher than the best average neutron yield of 3.18x10 8 neutrons per shot for pure deuterium operation. Estimation of average neutron energy showed that the maximum and minimum average energies are 2.98±0.6 MeV at 16 kV in 0.25 Torr deuterium with 3% Kr and 2.07±0.2 MeV at 18 kV operation in 0.5 Torr deuterium with 3% Kr, respectively. The anisotropy of neutron emission from Sahand DPF showed that the neutrons are produced mainly by beam-target mechanisms. -- Highlights: → The highest average neutron yield of 2.2x10 9 neutrons per shot was achieved at mixture of deuterium and krypton. → In the krypton seeding of deuterium also anisotropy of neutron emission deuterium is found. → The krypton seeding of deuterium made the neutron emission more reliable over wider operating pressure ranges.

Application of fluoridated hydroxyapatite thin film coatings using KrF pulsed laser deposition.

Science.gov (United States)

Hashimoto, Yoshiya; Ueda, Mamoru; Kohiga, Yu; Imura, Kazuki; Hontsu, Shigeki

2018-06-08

Fluoridated hydroxyapatite (FHA) was investigated for application as an implant coating for titanium bone substitute materials in dental implants. A KrF pulsed excimer deposition technique was used for film preparation on a titanium plate. The compacts were ablated by laser irradiation at an energy density of 1 J/cm 2 on an area 1×1 mm 2 with the substrate at room temparature. Energydispersive spectrometric analysis of the FHA film revealed peaks of fluorine in addition to calcium and phosphorus. X-ray diffraction revealed the presence of crystalline FHA on the FHA film after a 10 h post annealing treatment at 450°C. The FHA film coating exhibited significant dissolution resistance to sodium phosphate buffer for up to 21 days, and favorable cell attachment of human mesenchymal stem cells compared with HA film. The results of this study suggest that FHA coatings are suitable for real-world implantation applications.

Clinical Observation on the Therapeutic effect of ocular Fundus Disease with multi Wavelength Krypton laser Treatment%眼底病采用多波长氪离子激光治疗的临床疗效观察

Institute of Scientific and Technical Information of China (English)

钱江

2014-01-01

目的：分析探讨眼底病采用多波长氪离子激光治疗的临床疗效。方法选取40例（60眼）眼底病患者作为研究对象，分为观察组与对照组，每组20例（30眼），对照组患者行复方血塞通胶囊治疗，观察组在对照组治疗的基础上行多波长氪离子激光治疗，比较两组治疗情况。结果观察组治疗总有效率为90.0%，对照组治疗总有效率为75.0%，观察组治疗效果明显优于对照组（P<0.05）；观察组并发症发生率明显低于对照组（P<0.05），组间比较有统计学意义。结论眼底病采用多波长氪离子激光治疗具有显著的临床疗效，且无不良反应，有效性与安全性均有保证，可推广应用。%Objective To investigate the clinical efficacy of ocular fundus disease analysis using multi wavelength krypton laser treatment.Methods 40 cases(60 eyes)of ocular fundus disease patient as the research object,divided into observation group and control group,each group of 20 cases(30 eyes),the control group underwent compound Xuesaitong capsule treatment,observation group in the control group treatment on the basis of krypton ion laser treatment,compared two groups of treatment.Results In the observation group,the total effective rate was 90%,the control group the total effective rate was 75%,the patients in the observation group was better than the control group(P<0.05);The complication rate of observation group was significantly lower than the control group(P<0.05),there was significant difference between group.Conclusion The ocular fundus disease with multi wavelength krypton laser therapy has remarkable clinical curative effect,and no adverse reaction,effectiveness and safety can be guaranteed,and can be popularized and applied.

Feasibility of Single Scan for Simultaneous Evaluation of Regional Krypton and Iodine Concentrations with Dual-Energy CT: An Experimental Study.

Science.gov (United States)

Hong, Sae Rom; Chang, Suyon; Im, Dong Jin; Suh, Young Joo; Hong, Yoo Jin; Hur, Jin; Kim, Young Jin; Choi, Byoung Wook; Lee, Hye-Jeong

2016-11-01

Purpose To evaluate the feasibility of a simultaneous single scan of regional krypton and iodine concentrations by using dual-energy computed tomography (CT). Materials and Methods The study was approved by the institutional animal experimental committee. An airway obstruction model was first made in 10 beagle dogs, and a pulmonary arterial occlusion was induced in each animal after 1 week. For each model, three sessions of dual-energy CT (80% krypton ventilation [krypton CT], 80% krypton ventilation with iodine enhancement [mixed-contrast agent CT], and iodine enhancement [iodine CT]) were performed. Krypton maps were made from krypton and mixed-contrast agent CT, and iodine maps were made from iodine and mixed-contrast agent CT. Observers measured overlay Hounsfield units of the diseased and contralateral segments on each map. Values were compared by using the Wilcoxon signed-rank test. Results In krypton maps of airway obstruction, overlay Hounsfield units of diseased segments were significantly decreased compared with those of contralateral segments in both krypton and mixed-contrast agent CT (P = .005 for both). However, the values of mixed-contrast agent CT were significantly higher than those of krypton CT for both segments (P = .005 and .007, respectively). In iodine maps of pulmonary arterial occlusion, values were significantly lower in diseased segments than in contralateral segments for both iodine and mixed-contrast agent CT (P = .005 for both), without significant difference between iodine and mixed-contrast agent CT for both segments (P = .126 and .307, respectively). Conclusion Although some limitations may exist, it might be feasible to analyze regional krypton and iodine concentrations simultaneously by using dual-energy CT. © RSNA, 2016.

Krypton-85 and other airborne radioactivity measurements throughout Ireland

International Nuclear Information System (INIS)

Smith, K.J.; Murray, M.; Wong, J.; Sequeira, S.; Long, S.C.; Rafferty, B.

2004-01-01

In compliance with articles 35 and 36 of the EURATOM Treaty, the Radiological Protection Institute of Ireland (RPII) undertakes a comprehensive programme of radioactivity monitoring in the Irish terrestrial environment. Radioactivity is present in the terrestrial environment due to natural processes, the testing of nuclear weapons in the atmosphere, accidents such as the Chernobyl accident and the routine discharge of radionuclides from nuclear installations. The RPII monitors airborne radioactivity concentrations at ten stations throughout Ireland, of which, nine are equipped with low volume particulate samplers and one, in Dublin, with a high volume particulate sampler. The low volume particulate samples are assessed for total beta activity and high volume samples for gamma emitting radionuclides such as caesium-137 and beryllium-7. In addition, air sampled at the RPII laboratory in Dublin, is monitored for krypton-85, a radioactive noble gas, released into the environment primarily as a result of the reprocessing of nuclear fuel at installations such as Sellafield in the UK and La Hague in France. Since the inception of the krypton measurements in 1993 a trend of increasing atmospheric concentrations has been observed. The results of the krypton-85 monitoring, as well as the airborne radioactivity concentration measurements, will be presented and discussed in this paper. (author)

[Effects of xenon and krypton-containing breathing mixtures on clinical and biochemical blood indices in animals].

Science.gov (United States)

Kussmaul', A R; Bogacheva, M A; Shkurat, T P; Pavlov, B N

2007-01-01

Effects of 24-hr breathing air mixtures containing xenon (XBM) and krypton (KBM) were compared in terms of hormonal status, and blood biochemical indices and morphology in laboratory animals. Some changes observed in blood and hormone indices could be a nonspecific adaptive response. Hence, we should elicit whether these effects are quickly reversible or long. For several indices krypton was a more favorable factor than xenon. However, some of its effects invite to delve into effects of different krypton concentrations on organism.

Clinical Curative Effect of Different Wavelength Krypton Lasers in Treat-ment of Fundus Diseases%多波长氪离子激光治疗眼底病临床疗效探讨

Institute of Scientific and Technical Information of China (English)

杨露

2015-01-01

目的：探讨多波长氪离子激光治疗眼底病的临床疗效，以为其临床推广使用提供科学依据。方法随机选取该院眼科2012年5月-2014年9月收治的80例（100眼）眼底病患者为研究对象，经该院伦理委员会批准及患者知情同意下由临床医师采取等距随机抽样法分为对照组与研究组各40例（50眼），对照组采用复方血塞通胶囊垣维生素治疗，研究组采取多波长氪离子激光治疗，术后随访6个月时间，比对两组患者临床疗效及并发症发生率。结果研究组患者通过采取多波长氪离子激光治疗，总有效率90%、并发症发生率10%，与对照组80%、20%相比较，组间差异有统计学意义（P<0.05）。结论多波长氪离子激光治疗眼底病疗效确切、并发症发生率低、安全性高，值得在今后眼底病临床治疗中推广使用。%Objective To explore the clinical curative effects of different wavelength krypton lasers in the treatment of fundus dis-eases so as to provide a scientific basis for its clinical use. Methods Approved by the ethics committee of our hospital and with patients' informed consent, clinicians selected 80 patients (100 eyes) with fundus diseases admitted to the Department of Ophthal-mology as the research object and divide them into control group and study group using isometric random sampling method with 40 case (50 eyes) in each group. The control group was treated with compound xuesaitong capsule and vitamin, while the study group with different wavelength krypton lasers. The clinical effects and complication rates were compared between the two groups based on a 6 months follow-up. Results There were statistically significant differences in total effective rate and complication rate be-tween the two groups, 90% vs 10% and 80% vs 20%, P<0.05. Conclusion Different wavelength krypton lasers are worthy of pro-motion in the future treatment of fundus diseases due to its definite

Effects of the low-intensity laser therapy on the prevention of dental caries induced in rats; Efeitos da radiacao laser em baixa intensidade na prevencao de carie dental induzida em ratos

Energy Technology Data Exchange (ETDEWEB)

Mueller, Karin Praia

2004-07-01

The purpose of this study was to investigate the effects of low intensity laser therapy, associated or not to an acidulated phosphate fluoride, on the prevention of dental caries induced in rats. It was used 40 wistar rats, female, weaned with 18 days, fed with a cariogenic diet during 48 days and inoculated orally with Streptococcus mutans by three consecutive days starting from the second day of the diet. On the fifth day of experiment the animals were divided into five groups: G{sub c} (control) the animas were no submitted to any treatment; G{sub L} (laser) irradiation with low power laser (GaAlAs, {lambda}=660 nm, P=30 mW, {delta}t=5 sec, 5 J/cm{sup 2}); G{sub F} (fluoride) topical application of acidulated phosphate fluoride (APF 1,23%) for four minutes; G{sub LF} (laser + fluoride) irradiation with low power laser followed by topical application of acidulated phosphate fluoride; G{sub FL} (fluoride + laser) topical application of acidulated phosphate fluoride followed by low power laser. The animals were sacrificed after 48 days; the molars were extracted and prepared to determine the dental caries lesions area by optical microscopy, enamel microhardness and analysis of the calcium and phosphorus ratio (Ca/P) by energy dispersive spectroscopy. The results were statistically analyzed by ANOVA (plaser radiation associated with acidulated phosphate fluoride reduces the caries area and could be an alternative in the prevention of the dental caries. (author)

Stabilization of fluoroindate glasses by magnesium fluoride and other heavy metal fluorides

Directory of Open Access Journals (Sweden)

B. J. Costa

1998-06-01

Full Text Available Their extended transparency in the IR makes them attractive for use as optical fibers for CO laser power delivery and optical amplification. This paper firstly describes the spectacular stabilizing effect of MgF2 on the binary system InF3-BaF2. The investigation of the InF3-BaF2-MgF2 system led to samples up to 5mm in thickness. Further optimization of this system was achieved by incorporation of limited amounts of other fluorides and resulted in increased resistence to devitrification. The second approach of this work was concerned to the investigation of the pseudo-ternary system InF3-GdF3-GaF3 at constant concentrations of ZnF2-SrF2-BaF2-NaF. Several compositions were studied in this system. The samples presented a better thermal stability when compared to other families of fluoride glasses. Therefore, these glasses seem to be very promising for the fabrication of special optical fibers. Thermal data are reported.

Urinary fluoride excretion after application of fluoride varnish and use of fluoride toothpaste in young children

DEFF Research Database (Denmark)

Lockner, Frida; Twetman, Svante; Stecksén-Blicks, Christina

2017-01-01

BACKGROUND: The efficacy and safety of combined use of topical fluoride products are essential issues that must be monitored. AIM: To assess urinary excretion of fluoride after application of two different dental varnishes containing 2.26% fluoride in 3- to 4-year-old children and to compare...... the levels with and without parallel use of fluoride toothpaste. DESIGN: Fifteen healthy children were enrolled to a randomized crossover trial that was performed in two parts: Part I with twice-daily tooth brushing with fluoride toothpaste and Part II with twice-daily brushing with a non-fluoride toothpaste....... After a 1-week run-in period, 0.1 mL of the two fluoride varnishes (Duraphat and Profluorid Varnish) was topically applied in a randomized order. Baseline and experimental urine was collected during 6-h periods. The fluoride content was determined with an ion-sensitive electrode. RESULTS...

The NA62 Liquid Krypton Electromagnetic Calorimeter Level 0 Trigger

CERN Document Server

INSPIRE-00293812; Paoluzzi, Giovanni; Salamon, Andrea; Salina, Gaetano; Santovetti, Emanuele; Scarfi, Francesco M.; Bonaiuto, Vincenzo; Sargeni, Fausto

2012-01-01

The NA62 experiment at CERN SPS aims to measure the Branching Ratio of the very rare kaon decay K+ -> pi+ nu nubar collecting O(100) events with a 10% background to make a stringent test of the Standard Model. One of the main backgrounds to the proposed measurement is represented by the K+ -> pi+ pi0 decay. To suppress this background an efficient photo veto system is foreseen. In the 1-10 mrad angular region the NA48 high performance liquid krypton electromagnetic calorimeter is used. The design, implementation and current status of the Liquid Krypton Electromagnetic Calorimeter Level 0 Trigger are presented.

The NA62 Liquid Krypton Electromagnetic Calorimeter Level 0 Trigger

CERN Document Server

INSPIRE-00646848; Fucci, Adolfo; Paoluzzi, Giovanni; Salamon, Andrea; Salina, Gaetano; Santovetti, Emanuele; Scarfi, Francesco M.; Sargeni, Fausto

2011-01-01

The NA62 experiment at CERN SPS aims to measure the Branching Ratio of the very rare kaon decay K+ -> pi+ nu nubar collecting O(100) events with a 10% background to make a stringent test of the Standard Model. One of the main backgrounds to the proposed measurement is represented by the K+ -> pi+ pi0 decay. To suppress this background an efficient photo veto system is foreseen. In the 1-10 mrad angular region the NA48 high performance liquid krypton electromagnetic calorimeter is used. The design, implementation and current status of the Liquid Krypton Electromagnetic Calorimeter Level 0 Trigger are presented.

Effects of the low-intensity laser therapy on the prevention of dental caries induced in rats

International Nuclear Information System (INIS)

Mueller, Karin Praia

2004-01-01

The purpose of this study was to investigate the effects of low intensity laser therapy, associated or not to an acidulated phosphate fluoride, on the prevention of dental caries induced in rats. It was used 40 wistar rats, female, weaned with 18 days, fed with a cariogenic diet during 48 days and inoculated orally with Streptococcus mutans by three consecutive days starting from the second day of the diet. On the fifth day of experiment the animals were divided into five groups: G c (control) the animas were no submitted to any treatment; G L (laser) irradiation with low power laser (GaAlAs, λ=660 nm, P=30 mW, Δt=5 sec, 5 J/cm 2 ); G F (fluoride) topical application of acidulated phosphate fluoride (APF 1,23%) for four minutes; G LF (laser + fluoride) irradiation with low power laser followed by topical application of acidulated phosphate fluoride; G FL (fluoride + laser) topical application of acidulated phosphate fluoride followed by low power laser. The animals were sacrificed after 48 days; the molars were extracted and prepared to determine the dental caries lesions area by optical microscopy, enamel microhardness and analysis of the calcium and phosphorus ratio (Ca/P) by energy dispersive spectroscopy. The results were statistically analyzed by ANOVA (p LF was smaller than that for G F and G FL groups but no statistical difference was observed. There was no significant statistical difference between the microhardness of the G C and G L groups and among G FL , G LF and G F groups. Regarding to the calcium and phosphorus ratio, it was not observed significant statistical differences among the groups. These findings suggest that low-intensity laser radiation associated with acidulated phosphate fluoride reduces the caries area and could be an alternative in the prevention of the dental caries. (author)

Nuclear reactions and application to production rates of krypton in extraterrestrial materials

International Nuclear Information System (INIS)

Lavielle, B.

1982-01-01

Noble gases have been largely outgassed from most solar system materials through several heating processes. Consequently, their cosmogenic component, produced by cosmic-ray-induced nuclear reactions near the surface of atmosphere-free planetary objects, is detectable in meteorites and lunar samples. This work deals with the production of cosmogenic Krypton in the four main targets Zr, Y, Sr and Rb. Excitation functions of Krypton isotopes with A = 78, 80, 81, 82, 83, 84, 85 and 86 were mass-spectrometrically measured in Y and Zr targets bombarded with 0.059, 0.075, 0.168, 0.200, 1.0, 2.5 and 24 GeV protons. Also the Krypton relative cross sections were measured in Sr at 0.168 GeV. The results, combined with a general survey of nuclear reactions in Ga to Nb targets, permitted the development of new systematics in order to estimate unknown cross-sections in Rb and Sr. Measured and estimated excitation functions allowed to calculate the concentrations and isotopic ratios of cosmogenic Krypton in same well-documented lunar samples. Compared to observed values in 9 rocks, 83 Kr is predicted with a precision better than 33% and the production ratios sup(i)Kr/ 83 Kr are predicted to better than 25%. Also it is concluded that the cosmogenic ratios 86 Kr/ 83 Kr and 81 Kr/ 83 Kr are dependent on the main target elements concentrations [fr

Radiometric titration of officinal radiopharmaceuticals using radioactive kryptonates as end-point indicators. II

International Nuclear Information System (INIS)

Harangozo, M.; Jombik, J.; Schiller, P.; Toelgyessy, J.

1981-01-01

A method for the determination of citric, tartaric and undecylenic acids based on radiometric titration with 0.1 or 0.05 mole.l -1 NaOH was developed. As an indicator of the end point, radioactive kryptonate of glass was used. Experimental technique, results of determinations as well as other possible applications of the radioactive kryptonate of glass for end point determination in alkalimetric analyses of officinal pharmaceuticals are discussed. (author)

Laser development for laser fusion applications. Research progress report, October 1979-September 1980

International Nuclear Information System (INIS)

1981-04-01

Research conducted during this period is reported on the following: (1) rare-gas-halogen lasers, (2) XeCl laser at excitation rates of 1.7 to 4.7 MW/cm 3 , (3) rare gas halogen laser modeling, (4) three-body ion recombination coefficients, (5) electron beam accelerators, (6) power conditioning studies for accelerators, (7) chemically pumped iodine lasers, (8) hydrogen fluoride lasers, and (9) supporting research

The mutual influence of krypton implantation and pre-existing stress states in polycrystalline alpha titanium

Energy Technology Data Exchange (ETDEWEB)

Nsengiyumva, S. [Department of Physics, University of Cape Town, Rondebosch 7701 (South Africa); Department of Physics, Kigali Institute of Education, P.O. Box 5039 Kigali (Rwanda)], E-mail: schadrack.nsengiyumva@uct.ac.za; Ntsoane, T.P. [Nuclear Energy Corporation of South Africa (NECSA), P.O. Box 582 (South Africa); Raji, A.T. [Department of Physics, University of Cape Town, Rondebosch 7701 (South Africa); Topic, M. [iThemba LABS, Somerset West 7129 (South Africa); Kellermann, G. [Laboratorio Nacional de Luz Sincrotron (LNLS), Campinas (Brazil); Riviere, J.P. [Laboratoire de Physique des Materiaux UMR6630-CNRS, 86960 (France); Britton, D.T.; Haerting, M. [Department of Physics, University of Cape Town, Rondebosch 7701 (South Africa)

2009-08-15

The stress profile in polycrystalline titanium implanted with krypton ions at different fluences has been determined using synchrotron radiation diffraction. For each fluence, the krypton profile has been measured using Rutherford backscattering geometry. The results were compared to model calculations obtained from the SRIM 2008 computer code. A strong stress relaxation was found for high fluence implantation, whereas for low fluence implantation an additional source of tensile stress was introduced in the near surface region. The projected range of the implanted krypton was significantly reduced compared to the expected range. A possible cause of this discrepancy is the drift of implanted ions under the influence of the pre-existing stress gradient.

The mutual influence of krypton implantation and pre-existing stress states in polycrystalline alpha titanium

International Nuclear Information System (INIS)

Nsengiyumva, S.; Ntsoane, T.P.; Raji, A.T.; Topic, M.; Kellermann, G.; Riviere, J.P.; Britton, D.T.; Haerting, M.

2009-01-01

The stress profile in polycrystalline titanium implanted with krypton ions at different fluences has been determined using synchrotron radiation diffraction. For each fluence, the krypton profile has been measured using Rutherford backscattering geometry. The results were compared to model calculations obtained from the SRIM 2008 computer code. A strong stress relaxation was found for high fluence implantation, whereas for low fluence implantation an additional source of tensile stress was introduced in the near surface region. The projected range of the implanted krypton was significantly reduced compared to the expected range. A possible cause of this discrepancy is the drift of implanted ions under the influence of the pre-existing stress gradient.

Bonding xenon and krypton on the surface of uranium dioxide single crystal

Directory of Open Access Journals (Sweden)

Dąbrowski Ludwik

2014-08-01

Full Text Available We present density functional theory (DFT calculation results of krypton and xenon atoms interaction on the surface of uranium dioxide single crystal. A pseudo-potential approach in the generalised gradient approximation (GGA was applied using the ABINIT program package. To compute the unit cell parameters, the 25 atom super-cell was chosen. It has been revealed that close to the surface of a potential well is formed for xenon and krypton atom due to its interaction with the atoms of oxygen and uranium. Depth and shape of the well is the subject of ab initio calculations in adiabatic approximation. The calculations were performed both for the case of oxygenic and metallic surfaces. It has been shown that the potential well for the oxygenic surface is deeper than for the metallic surface. The thermal stability of immobilising the atoms of krypton and xenon in the potential wells were evaluated. The results are shown in graphs.

Simulations of Atmospheric Krypton-85 to Assess the Detectability of Clandestine Nuclear Reprocessing

International Nuclear Information System (INIS)

Ross, O.; Ahlswede, J.; Annewandter, R.; Kalinowski, M.B.; Rast, S.; Schluenzen, K.H.

2010-01-01

The results of this study were achieved in the project 'Simulation of Atmospheric Noble Gas Concentrations to Assess Sampling Procedures for the Detection of Clandestine Nuclear Reprocessing' (IAEA GER 1643) in the joint programme of IAEA and Federal Government of Germany. In the first year of the project the detectability of additional krypton-85 sources was investigated using atmospheric transport modelling. Krypton-85 is released into the air during reprocessing of spent nuclear fuel rods. Therefore the krypton-85 signature can possibly be used for the detection of undeclared plutonium separation. First, the global krypton-85 background produced by known reprocessing facilities from 1971 until 2006 was simulated with the atmospheric general circulation model ECHAM5 using annual emission data. The model results were evaluated by extensive comparison with measurements performed by the German Federal Office for Radiation Protection. Of particular interest for an assessment of the detectability of unknown sources is the background variability. The variability of concentrations is very high over central Europe, where the large reprocessing plants La Hague and Sellafield are located, and it is very low on the Southern Hemisphere, where no nuclear reprocessing takes place. The analysis of concentration time series on various time scales allows partly a distinction between fluctuations caused by the variability of the sources from variations due to atmospheric dynamics. Furthermore the detection sensitivity to a set of arbitrarily specified source locations is analysed with a Lagrangian particle dispersion model. This, in combination with the location specific background variability, is giving first benchmarks on the capability of using krypton-85 for IAEA Safeguards based on the Additional Protocols foreseeing environmental sampling. (author)

Immobilisation of krypton in a metallic matrix by combined ion implantation and sputtering

International Nuclear Information System (INIS)

Whitmell, D.S.

1980-01-01

With the increase in nuclear power, it may be necessary to contain for 100 to 200 years the radioactive 85 krypton released during fuel reprocessing. The ideal method of immobilising radioactive materials is in the form of stable, monolithic solids which are resistant to the effects of the environment or accidents, and which can retain the radioactivity under all envisaged conditions. Since krypton is a rare gas, not forming thermally stable compounds, conventional methods of storage are not possible. A process is being developed to immobilise the krypton in the form of small gas bubbles in a metal matrix by implanting the gas into a metal layer from a glow discharge and then burying the implanted layer by sputter deposition. By repeating the process, a thick layer of deposit is built up with the krypton dispersed throughout the matrix as bubbles of diameter less than 20 A. This process offers an ideal form of storage since gas in bubbles is not thermally released until the temperature of the matrix is close to the melting point, and also leakage of gas by corrosion or mechanical damage will be small. A pilot plant is being built in order to demonstrate the process on a scale comparable with that required for a reprocessing plant. The efficiency of the process is dependent upon the amount of gas which can be implanted at low energy into a thin layer and its subsequent retention. More information is required on the processes occurring when krypton ions are implanted close to the surface, in particular, the retention and re-emission of the gas, and the formation of clusters and bubbles. (author)

Resonance laser-plasma excitation of coherent terahertz phonons in the bulk of fluorine-bearing crystals under high-intensity femtosecond laser irradiation

Energy Technology Data Exchange (ETDEWEB)

Potemkin, F V; Mareev, E I [International Laser Center, M. V. Lomonosov Moscow State University, Moscow (Russian Federation); Khodakovskii, N G [A M Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation); Mikheev, P M

2013-08-31

The dynamics of coherent phonons in fluorine-containing crystals was investigated by pump-probe technique in the plasma production regime. Several phonon modes, whose frequencies are overtones of the 0.38-THz fundamental frequency, were simultaneously observed in a lithium fluoride crystal. Phonons with frequencies of 1 and 0.1 THz were discovered in a calcium fluoride crystal and coherent phonons with frequencies of 1 THz and 67 GHz were observed in a barium fluoride crystal. Furthermore, in the latter case the amplitudes of phonon mode oscillations were found to significantly increase 15 ps after laser irradiation. (interaction of laser radiation with matter)

间接镜氪激光光凝结合改进宽环扎治疗视网膜脱离%Krypton laser photocoagulation using indirect ophthalmoscopy combined with improved encircling scleral buckles in the treatment of retinal detachment

Institute of Scientific and Technical Information of China (English)

郑穗联; 陈如; 王若洁; 蔡剑秋; 施明光

2011-01-01

Objective To assess the clinical result of the krypton laser photocoagulation using indirect ophthalmoscopy combined with improved encircling scleral buckles.Methods Forty-one eyes of 41 patients were treated with encircling scleral buckles and drainage, some combined with intravitreal injection of gas or balanced salt solution (BSS).All of the retinal breaks were treated with krypton laser photocoagulation using indirect ophthalmoscopy after surgery.Results The visual acuity improved (P<0.05).The reattachment of the retina: 36 eyes were successfully repaired, 5 eyes became recurrent retinal detachment (the reattachment rate was 88.37%).Among the 5 cases, 4 patients were successfully treated with vitrectomy except one patient of traumatic retinal detachment was given up.Conclusions The treatment of retinal detachment should follow the principles of simple surgical methods and fewer complications.The krypton laser photocoagulation using indirect ophthalmoscopy combined with improved encircling scleral buckles in the treatment of retinal detachment in proper cases is a safe, simple and convenient, easy operated and effective method.%目的 讨论采用间接镜氪激光光凝结合改进宽环扎治疗视网膜脱离的临床疗效.方法 对41例41只眼PVRB级或以下的孔源性视网膜脱离病人行宽环扎、放液,部分病人联合玻璃体腔注气或平衡液,术后间接镜氪激光治疗视网膜裂孔.结果 视力提高:术后视力为3.87±0.74,术前视力为3.40±0.86,P<0.05.视网膜复位情况:41只眼中手术成功36只眼,5只眼复发性,成功率88.37%.5只眼复发性视网膜脱离,除1例外伤性视网膜脱离放弃手术外,其余患者均行玻璃体手术后复位.结论 对视网膜脱离术我们建议遵循手术方式简单、并发症少的原则.选择适当病例,间接镜氪激光光凝结合改进宽环扎治疗视网膜脱离是一种安全、简便、易操作、效果良好的方法.

Upconversion channels in Er3+ ZBLALiP fluoride glass microspheres

NARCIS (Netherlands)

O'Shea, D. G.; Ward, J. M.; Shortt, B. J.; Mortier, M.; Feron, P.; Chormaic, S. Nic

We present results on the realization of a multicolour microspherical glass light source fabricated from the erbium doped fluoride glass ZBLALiP. Whispering gallery mode lasing and upconversion processes give rise to laser and fluorescent emissions at multiple wavelengths from the ultraviolet to the

Krypton gas cylinders as a source of radiation.

Science.gov (United States)

Fischer, Helmut W; Bielefeld, Tom; Hettwig, Bernd

2010-07-01

A standard 40 foot shipping container with a cargo of pressurized krypton gas in 159 steel cylinders, which had triggered a radiation alarm, was investigated to address radiation safety and illicit nuclear trafficking concerns. The investigation included contamination and dose rate measurements as well as in situ high resolution gamma spectroscopy. The dose rate measurements gave a maximum value of 0.07 microSv h(-1) above background (0.08 to 0.11 microSv h(-1)) on the cylinder surface and no detectable increase above background at distances of 1 m and higher. Contamination monitor readings showed a similar relative increase (plus 8 cpm) above background (about 12 cpm) to the dose rate readings. Quantitative gamma spectroscopy revealed a contamination of the gas with 85Kr at a level of 3.5 x 10(5) Bq kg(-1). This value was found to be consistent with analytical and numerical estimates based on current data for atmospheric 85Kr, which is captured from ambient air together with stable krypton during the production process. This incident demonstrates an apparent lack of radiation-related knowledge by those who handle krypton gas, as well as by border control personnel and emergency responders. We therefore propose to improve labeling and documentation standards for such shipments. This effort may be facilitated by introducing the new category of "technically enhanced artificial radioactive material," or "TEARM" (similar to the existing "naturally occurring radioactive material" or "NORM" and "technically enhanced naturally occurring radioactive material" or "TENORM" categories).

The effect of a chlorhexidine-fluoride varnish on mutans streptococci counts and laser fluorescence readings in occlusal fissures of permanent teeth

DEFF Research Database (Denmark)

Lipták, Lídia; Bársony, Nóra; Twetman, Svante

2016-01-01

Objective: To evaluate the effect of a new chlorhexidinefluor ide varnish on mutans streptococci (MS) counts and laser fluorescence (LF) readings in fissures of permanent molars. Method and Materials: The study group consisted of 57 healthy schoolchildren (7 to 14 yrs) that volunteered after...... informed consent. A double-blind split-mouth design was employed and 87 pairs of non-cavitated permanent molars were randomly assigned to treatments with either chlorhexidine- fluoride varnish (CHX-F) or chlorhexidine-thymol varnish (CHX-T, Cervitec Plus) as active control. The varnishes were topically...

Particle dynamics during electronic sputtering of solid krypton

DEFF Research Database (Denmark)

Dutkiewicz, L.; Pedrys, R.; Schou, Jørgen

1995-01-01

We have modeled electronic sputtering of solid krypton by excimer production with molecular dynamics. Both excimer evolution in the solid and deexcitation processes have been incorporated in the simulation. The excimer dynamics in the lattice has been analyzed: the excimers formed near the surface...

Variability of atmospheric krypton-85 activity concentrations observed close to the ITCZ in the southern hemisphere.

Science.gov (United States)

Bollhöfer, A; Schlosser, C; Ross, J O; Sartorius, H; Schmid, S

2014-01-01

Krypton-85 activity concentrations in surface air have been measured at Darwin, which is located in northern Australia and is influenced by seasonal monsoonal activity. Measurements between August 2007 and May 2010 covered three wet seasons. The mean activity concentration of krypton-85 measured during this period was 1.31±0.02Bqm(-3). A linear model fitted to the average monthly data, using month and monsoon as predictors, shows that krypton-85 activity concentration measured during the sampling period has declined by 0.01Bqm(-3) per year. Although there is no statistically significant difference in mean activity concentration of krypton-85 between wet and dry season, the model implies that activity concentration is higher by about 0.015Bqm(-3) during months influenced by the monsoon when a north westerly flow prevails. Backward dispersion runs using the Lagrangian particle dispersion model Hysplit4 highlight possible source regions during an active monsoon located deep in the northern hemisphere, and include reprocessing facilities in Japan and India. However, the contribution of these facilities to krypton-85 activity concentrations in Darwin would be less than 0.003Bqm(-3). Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

Study on the possibility of sea-disposal of krypton-85

International Nuclear Information System (INIS)

Dalen, A. van; Vons, L.H.; Verkerk, B.

1980-01-01

Results of a feasibility study, performed under a contract with the Commission of the European Communities, regarding technical and radiological aspects of sea-disposal of all krypton-85 retained in a large fuel reprocessing facility, are presented. The design of a double-walled, essentially spherical container is described that provides both double containment of the compressed gas and permanent 'disposable' radiation shielding. Three sizes have been studied, i.e. with internal volumes of 0.01, 0.05 and 0.1 m 3 , each designed to hold 0.1 m 3 (STP) of krypton, and each containing approximately 400 TBq of 85 Kr per 0.001 m 3 sphere volume. This results in an internal heat production of 17.5 kW/m 3 . Calculations of temperatures and stresses that would result from the conditions of the required fire test for B(U) transport packages showed that the design would allow the containers to pass this test. Radiological consequences have been considered for disposal of petabecquerel amounts of 85 Kr as a function of undamaged container lifetime on the sea bed. Finally, an indication is given of the necessary amendments to the London Convention in order to allow sea-disposal of these large amounts of radioactive krypton. (author)

The place of krypton-81m ventilation in the scintigraphic investigation of the lung

International Nuclear Information System (INIS)

Hoefnagel, C.A.; Marcuse, H.R.

1983-01-01

Fairly recently krypton-81m gas became available for diagnostic purposes. Its advantages and ways to use are surveyed especially for the diagnosis of lung emboli and lung diseases. The combination of perfusion and ventilation scintigrams is the best for specifying the diagnosis. Krypton-81m gas improves the specificity and sensitivity of the examination which is non-invasive and carries no burden for the patient. (Auth.)

Enrichment Conditions of Krypton Onto Activated Carbons%活性炭对氪的富集条件

Institute of Scientific and Technical Information of China (English)

陈莉云; 曾宝珠; 张昌云; 武山; 刘龙波; 杨静; 韦冠一

2012-01-01

In order to monitor radioactive krypton distribution in the environment, active charcoal is used to enrich krypton before the sample can be submitted to further laboratory analysis. The importance and method of krypton enrichment were presented. The absorption behavior of krypton by charcoal was analyzed. The experimental setup was designed to investigate effects of working temperature, linear velocities, partial-pressure of krypton on the enrichment of krypton by charcoal. The micro-structure parameters of the absorbing material to characterize its absorbing property was used, and the experimental data with theoretical analysis to conclude that for CF-1450 was fitted. The saturation absorption capacity at 191 K is 32. 9 mL/g.%从环境监测角度,叙述了开展活性炭对氪富集条件研究的重要意义.以氪在活性炭上的动态吸附实验为基础,研究了活性炭、温度、气体线流速和氪的分压对氪富集的影响,利用吸附材料的微结构,通过吸附理论模型拟合实验数据,得到CF-1450活性炭在191 K下对氪的饱和吸附量为32.9 mL/g.

Oxygen sensitivity of krypton and Lyman-alpha hygrometers

NARCIS (Netherlands)

Dijk, van A.; Kohsiek, W.; Bruin, de H.A.R.

2003-01-01

The oxygen sensitivity of krypton and Lyman-¿ hygrometers is studied. Using a dewpoint generator and a controlled nitrogen/oxygen flow the extinction coefficients of five hygrometers associated with the third-order Taylor expansion of the Lambert¿Beer law around reference conditions for oxygen and

Status of the NA62 liquid krypton electromagnetic calorimeter Level 0 trigger processor

CERN Document Server

Bonaiuto, V; Fucci, A; Paoluzzi, G; Salamon, A; Salina, G; Santovetti, E; Sargeni, F; Venditti, S

2013-01-01

The NA62 experiment at the CERN SPS aims to measure the Branching Ratio of the very rare kaon decay K(+)→π(+)νbar nu collecting O(100) events with a 10% background in two years of data taking. To reject the K(+)→π(+)π(0) background the NA48 liquid krypton calorimeter will be used in the 1-10 mrad angular region. The status of the Liquid Krypton Electromagnetic Calorimeter Level 0 Trigger is presented.

Radiation protection problems in using krypton 81 m in pulmonary ventilation scintiscanning

International Nuclear Information System (INIS)

Spesshardt, K.

1982-01-01

The experience gained in using the krypton-81 generator as regards radiation protection is briefly outlined by means of measurements, carried through in the framework of the operation licensing procedure. It turned out that while krypton is a very helpful substance in clinical investigations on account of its favourable gamma energy and very short half-life, it does create some radiation protection problems. The radiation protection measures carried through at the inhalation system can be described as satisfactory. Improvements are due at the filter system between generator and breathing mask. (orig./DG) [de

X-ray spectroscopic measurements of dielectronic recombination of highly charged krypton ions

International Nuclear Information System (INIS)

Biedermann, C.; Fuchs, T.; Liebisch, P.; Radtke, R.; Behar, E.; Doron, R.

1999-01-01

We have performed X-ray spectroscopic measurements of the dielectronic recombination (DR) resonance strengths for the KLn (n = 2, .., 5) series of He-, Li-, and Be-like krypton ions. The ions were produced with an electron beam ion trap, and the strengths were obtained from a fit procedure that compares the experimental excitation function for DR to theory. The results agree well with the predictions. By looking at the KLL resonance, the time evolution of different krypton charge states was measured with this technique and compared with a model of the trap inventory. (orig.)

Experimental Investigations of a Krypton Stationary Plasma Thruster

Directory of Open Access Journals (Sweden)

A. I. Bugrova

2013-01-01

Full Text Available Stationary plasma thrusters are attractive electric propulsion systems for spacecrafts. The usual propellant is xenon. Among the other suggested propellants, krypton could be one of the best candidates. Most studies have been carried out with a Hall effect thruster previously designed for xenon. The ATON A-3 developed by MSTU MIREA (Moscow initially defined for xenon has been optimized for krypton. The stable high-performance ATON A-3 operation in Kr has been achieved after optimization of its magnetic field configuration and its optimization in different parameters: length and width of the channel, buffer volume dimensions, mode of the cathode operation, and input parameters. For a voltage of 400 V and the anode mass flow rate of 2.5 mg/s the anode efficiency reaches 60% and the specific impulse reaches 2900 s under A-3 operating with Kr. The achieved performances under operation A-3 with Kr are presented and compared with performances obtained with Xe.

The application about krypton laser photocoagulation and intravitreal C3F8 in retinal detachment after vitrectomy%氪激光联合玻璃体腔C3F8填充在玻璃体切除术后视网膜脱离中的应用

Institute of Scientific and Technical Information of China (English)

李红; 蒋模; 蔡善君

2013-01-01

目的 探讨氪激光视网膜光凝联合玻璃体腔注气术在玻璃体切除、眼内气体填充术后发生视网膜脱离中的适应症及临床疗效.方法 对30例因视网膜脱离或玻璃体积血行玻璃体切割、眼内光凝、联合SF6或C3F8填充,术后发现局限性视网膜再脱离的患者采用双针法行玻璃体注气联合视网膜氪激光光凝筑堤的办法,以闭合裂孔,复位视网膜脱离.术中采取双针法交换玻璃体腔部分房水,术后俯卧位休息12～18 h后予全视网膜镜下寻找裂孔,并激光光凝裂孔周围视网膜,激光参数为:能量180～300 mw,曝光时间0.2 s,光斑直径200～300 μm.结果 30眼中,玻璃体腔注C3F8气体联合氪绿激光光凝术后25只眼视网膜脱离复位,随诊3～18月视网膜稳定；4只眼视网膜未能复位,再次行玻璃体腔灌注,视网膜激光光凝及硅油填充,随访6月视网膜脱离复位,术后1只眼未能随访.结论 对于玻璃体切割术后的发生视网膜脱离患者,行氪绿激光光凝联合玻璃体腔注长效气体术是一种操作简单、节省治疗时间和费用较为理想的治疗方法.%OBJECTIVE To investigate the effect about krypton laser photocoagulation with long-gas injection in eyes in the recurrent retinal detachment after vitrectomy and long-acting gas injection. METHODS For 30 cases with retinal detachment and vitreous hemorrhage, carried out vitrectomy surgery combined with SF6 or C3F8 filled, postoperatively found that limitations of retinal detachment in patients used double needle vitreous gas injection combined with retinal krypton laser photocoagulation embankment approach to close the hole and reattach retinal detachment. Took double needle to exchange aqueous Humour, postoperative prone position rest for 12 to 18 hours, then located holes and used laser photocoagulation around them, laser parameters; energy 180-300mw, exposure time 0.2S, spot diameter 200-300μ,m. RESULTS In 30 eyes

Influence of krypton atoms on the structure of hydrogenated amorphous carbon deposited by plasma enhanced chemical vapor deposition

Science.gov (United States)

Oliveira, M. H.; Viana, G. A.; de Lima, M. M.; Cros, A.; Cantarero, A.; Marques, F. C.

2010-12-01

Hydrogenated amorphous carbon (a-C:H) films were prepared by plasma enhanced chemical vapor deposition using methane (CH4) plus krypton (Kr) mixed atmosphere. The depositions were performed as function of the bias voltage and krypton partial pressure. The goal of this work was to study the influence of krypton gas on the physical properties of a-C:H films deposited on the cathode electrode. Krypton concentration up to 1.6 at. %, determined by Rutherford Back-Scattering, was obtained at high Kr partial pressure and bias of -120 V. The structure of the films was analyzed by means of optical transmission spectroscopy, multi-wavelength Raman scattering and Fourier Transform Infrared spectroscopy. It was verified that the structure of the films remains unchanged up to a concentration of Kr of about 1.0 at. %. A slight graphitization of the films occurs for higher concentration. The observed variation in the film structure, optical band gap, stress, and hydrogen concentration were associated mainly with the subplantation process of hydrocarbons radicals, rather than the krypton ion energy.

Influence of krypton atoms on the structure of hydrogenated amorphous carbon deposited by plasma enhanced chemical vapor deposition

International Nuclear Information System (INIS)

Oliveira, M. H. Jr.; Viana, G. A.; Marques, F. C.; Lima, M. M. Jr. de; Cros, A.; Cantarero, A.

2010-01-01

Hydrogenated amorphous carbon (a-C:H) films were prepared by plasma enhanced chemical vapor deposition using methane (CH 4 ) plus krypton (Kr) mixed atmosphere. The depositions were performed as function of the bias voltage and krypton partial pressure. The goal of this work was to study the influence of krypton gas on the physical properties of a-C:H films deposited on the cathode electrode. Krypton concentration up to 1.6 at. %, determined by Rutherford Back-Scattering, was obtained at high Kr partial pressure and bias of -120 V. The structure of the films was analyzed by means of optical transmission spectroscopy, multi-wavelength Raman scattering and Fourier Transform Infrared spectroscopy. It was verified that the structure of the films remains unchanged up to a concentration of Kr of about 1.0 at. %. A slight graphitization of the films occurs for higher concentration. The observed variation in the film structure, optical band gap, stress, and hydrogen concentration were associated mainly with the subplantation process of hydrocarbons radicals, rather than the krypton ion energy.

Build up of Radioactive Krypton and Xenon Analysis System

International Nuclear Information System (INIS)

Lee, D. K.; Choi, C. S.; Chung, K. H.; Lee, W.; Cho, Y. H.; Lee, C. W.

2008-03-01

The objective of this project is to build up an analysis system to measure the activity of the atmospheric radioactive krypton and xenon in Korea. The work scopes of the project include the purchase and the installation of the analysis system to measure the activity of the radioactive krypton and xenon in air, and the establishment of the operation capability of the system through the training of the operator. The system consists of two air sampling systems, and one radioactivity analysis system, which incorporates the enrichment system, the gas chromatography to purify a mixture gas, and the gas proportional counter to count the activity of pure krypton and xenon gas. As planned originally, the establishment of the analysis system has been completed. At present, one air sampler is successfully being operated at a specific site of the South Korea to measure the background radioactivities of Kr-85 and Xe-133 in air. The other air sampler is being reserved at the KAERI in the Daejeon for a emergency like the second nuclear test of the North Korea. During the normal time, the reserved air sampler will be used to collect the air sample for the performance test of the analysis system and the cross analysis for the calibration of the system. The radioactivity analysis system has been installed at the KAERI, and is being used to measure the activity of Kr-85 and Xe-133 in the air sample from a domestic site

Continuous determination of regional myocardial blood flow with intracoronary krypton-81m in coronary artery disease

International Nuclear Information System (INIS)

Remme, W.J.; Krauss, X.H.; van Hoogenhuyze, D.C.; Cox, P.H.; Storm, C.J.; Kruyssen, D.A.

1985-01-01

Pacing-induced changes in regional coronary flow were studied continuously with krypton-81m by intracoronary infusion in 25 patients: 21 with 50% or greater diameter narrowing of 1 or more left coronary arteries (group I) and 4 with less than 50% diameter reduction of a left coronary artery (group II). No changes occurred in group II. In group I, krypton-81m perfusion decreased progressively in all areas with more than 70% diameter narrowing, with a simultaneous increase in normal regions. At the end of pacing during angina, krypton-81m perfusion was reduced to 81 +/- 4% of control in areas with 71 to 90% diameter reduction (n = 8) and to 69 +/- 6% in areas with more than 90% diameter narrowing (n = 15). In contrast, in regions with 50 to 70% diameter reduction changes were variable (decrease in 4 regions, increase in 2 and an unchanged distribution in 1 region). Krypton-81m perfusion decreased early, before general signs of ischemia in areas with more than 90% diameter reduction, whereas this decrease occurred later in regions with 71 to 90% diameter narrowing, concurrently with ST-segment changes but before anginal pain. Although all signs of ischemia had disappeared between 2 and 5 minutes after pacing, changes in krypton-81m distribution persisted in most areas for 5 to 15 minutes after pacing. It is concluded that the functional significance of coronary arterial narrowing can be assessed with a continuous intracoronary infusion of krypton-81m. Changes in regional distribution persisted after cessation of pacing-induced ischemia, indicating an ongoing decrease in regional myocardial blood flow

Analysis of HARP TPC krypton data

CERN Document Server

Dydak, F

2004-01-01

This memo describes the procedure which was adopted to equalize the response of the 3972 pads of the HARP TPC, using radioactive 83mKr gas. The results obtained from the study of reconstructed krypton clusters in the calibration data taken in 2002 are reported. Two complementary methods were employed in the data analysis. Compatible results were obtained for channel-to-channel equalization constants. An estimate of the overall systematic uncertainty was derived.

Thermophysical properties of krypton-helium gas mixtures from ab initio pair potentials.

Science.gov (United States)

Jäger, Benjamin; Bich, Eckard

2017-06-07

A new potential energy curve for the krypton-helium atom pair was developed using supermolecular ab initio computations for 34 interatomic distances. Values for the interaction energies at the complete basis set limit were obtained from calculations with the coupled-cluster method with single, double, and perturbative triple excitations and correlation consistent basis sets up to sextuple-zeta quality augmented with mid-bond functions. Higher-order coupled-cluster excitations up to the full quadruple level were accounted for in a scheme of successive correction terms. Core-core and core-valence correlation effects were included. Relativistic corrections were considered not only at the scalar relativistic level but also using full four-component Dirac-Coulomb and Dirac-Coulomb-Gaunt calculations. The fitted analytical pair potential function is characterized by a well depth of 31.42 K with an estimated standard uncertainty of 0.08 K. Statistical thermodynamics was applied to compute the krypton-helium cross second virial coefficients. The results show a very good agreement with the best experimental data. Kinetic theory calculations based on classical and quantum-mechanical approaches for the underlying collision dynamics were utilized to compute the transport properties of krypton-helium mixtures in the dilute-gas limit for a large temperature range. The results were analyzed with respect to the orders of approximation of kinetic theory and compared with experimental data. Especially the data for the binary diffusion coefficient confirm the predictive quality of the new potential. Furthermore, inconsistencies between two empirical pair potential functions for the krypton-helium system from the literature could be resolved.

High-Power Krypton Hall Thruster Technology Being Developed for Nuclear-Powered Applications

Science.gov (United States)

Jacobson, David T.; Manzella, David H.

2004-01-01

The NASA Glenn Research Center has been performing research and development of moderate specific impulse, xenon-fueled, high-power Hall thrusters for potential solar electric propulsion applications. These applications include Mars missions, reusable tugs for low-Earth-orbit to geosynchronous-Earth-orbit transportation, and missions that require transportation to libration points. This research and development effort resulted in the design and fabrication of the NASA-457M Hall thruster that has been tested at input powers up to 95 kW. During project year 2003, NASA established Project Prometheus to develop technology in the areas of nuclear power and propulsion, which are enabling for deep-space science missions. One of the Project-Prometheus-sponsored Nuclear Propulsion Research tasks is to investigate alternate propellants for high-power Hall thruster electric propulsion. The motivation for alternate propellants includes the disadvantageous cost and availability of xenon propellant for extremely large scale, xenon-fueled propulsion systems and the potential system performance benefits of using alternate propellants. The alternate propellant krypton was investigated because of its low cost relative to xenon. Krypton propellant also has potential performance benefits for deep-space missions because the theoretical specific impulse for a given voltage is 20 percent higher than for xenon because of krypton's lower molecular weight. During project year 2003, the performance of the high-power NASA-457M Hall thruster was measured using krypton as the propellant at power levels ranging from 6.4 to 72.5 kW. The thrust produced ranged from 0.3 to 2.5 N at a discharge specific impulse up to 4500 sec.

Laser fusion project second annual report

International Nuclear Information System (INIS)

Dumbaugh, W.H.; Morgan, D.W.; Flannery, J.E.

1978-01-01

This research program is devoted to the preparation and characterization of fluoride glasses for laser fusion. The overall objective is to explore and characterize fluoride glass systems to find a glass with the lowest possible nonlinear refractive index, satisfactory chemical durability, and physical properties which enable coating large optical quality pieces

Radiometric titration of officinal radiopharmaceuticals using radioactive kryptonates as end-point indicators. I. Salicylic, acetylosalicylic, benzoic acids

Energy Technology Data Exchange (ETDEWEB)

Toelgyessy, J; Dillinger, P [Slovenska Vysoka Skola Technicka, Bratislava (Czechoslovakia). Chemickotechnologicka Fakulta; Harangozo, M; Jombik, J [Komenskeho Univ., Bratislava (Czechoslovakia). Farmaceuticka Fakulta

1980-01-01

A method for the determination of salicylic, acetylsalicylic and benzoic acids in officinal pharmaceutical based on radiometric titration with 0.1 mol.l/sup -1/ NaOH was developed. The end-point was detected with the aid of radioactive glass kryptonate. After the end-point, the excess titrant attacks the glass surface layers and this results in releasing /sup 85/Kr, and consequently, in decreasing the radioactivity of the kryptonate employed. The radioactive kryptonate used as an indicator was prepared by the bombardment of glass with accelerated /sup 85/Kr ions. The developed method is simple, accurate and correct.

Soft X-ray imaging by optically stimulated luminescence from color centers in lithium fluoride

Energy Technology Data Exchange (ETDEWEB)

Bonfigli, F. [ENEA, C.R. Frascati, Via E. Fermi, 45, 00044 Frascati (Rome) (Italy)], E-mail: bonfigli@frascati.enea.it; Almaviva, S.; Baldacchini, G.; Bollanti, S.; Flora, F.; Lai, A.; Montereali, R.M. [ENEA, C.R. Frascati, Via E. Fermi, 45, 00044 Frascati (Rome) (Italy); Nichelatti, E. [ENEA, C.R. Casaccia, Via Anguillarese 301, 00060 S.Maria di Galeria (Rome) (Italy); Tomassetti, G.; Ritucci, A.; Reale, L. [Universita de L' Aquila e INFN, Dip. di Fisica, Coppito, L' Aquila (Italy); Faenov, A. Ya.; Pikuz, T.A. [MISDC of VNIIFTRI Mendeleevo, Moscow region, 141570 (Russian Federation); Larciprete, R. [ISC-CNR, Sezione Montelibretti, Via Salaria, Km. 29.3, 00016 Monterotondo Scalo (Rome) (Italy); Gregoratti, L.; Kiskinova, M. [Sincrotrone Trieste, S. S. 14, Km. 163.5, 34012 Basovizza (TS) (Italy)

2007-07-15

An innovative X-ray imaging detector based on Optically Stimulated Luminescence from color centers in lithium fluoride is presented. Regular photoluminescent patterns produced on LiF samples by different intense X-ray sources, like synchrotrons, laser plasma sources and a capillary discharge laser have been investigated by a Confocal Laser Scanning Microscope. The use of a LiF-based imaging plate for X-ray microscopy is also discussed showing microradiographies of small animals.

The effect of annealing unimplanted and krypton implanted uranium dioxide using positrons

International Nuclear Information System (INIS)

Evans, H.E.; Rice-Evans, P.; Smith, D.L.; Smith, C.; Evans, J.H.

1992-01-01

Previous studies examining the response of variable energy positrons to metals implanted with krypton ions have been extended to UO 2 . The behaviour of two Kr-implanted samples (one implanted at 300 K, the other at 870 K) during annealing up to 1350 K has been followed, together with an unimplanted, as-polished sample. There are several features of interest in the results although in these initial studies the interpretation is not always clear. Defect recovery and krypton effects can be identified but at high temperatures some suggestion of a sensitivity of positrons to stoichiometry is present

Variation on Molecular Structure, Crystallinity, and Optical Properties of Dentin Due to Nd:YAG Laser and Fluoride Aimed at Tooth Erosion Prevention

Science.gov (United States)

Freitas, Anderson Z.; Bachmann, Luciano; Benetti, Carolina; Ana, Patricia A.

2018-01-01

This in vitro study evaluated the compositional, crystalline, and morphological effects promoted by Nd:YAG laser on root dentin, and verified the effects of laser and topical acidulated phosphate fluoride application (APF-gel) on dentin erosion. 180 bovine dentin slabs were randomized into 4 groups (n = 45): G1–untreated, G2–APF-gel (1.23% F−, 4 min), G3–Nd:YAG (1064 nm, 84.9 J/cm2, 10 Hz), and G4–APF-gel application followed by Nd:YAG laser irradiation. The compositional, crystalline, and morphological effects promoted by treatments were investigated on five samples of each experimental group. The other samples were submitted to a 5-day, 10-day, or 15-day erosive and abrasive demineralization and remineralization cycling in order to create erosion lesions. The area and depth of lesions, as well as the optical attenuation coefficient, were assessed, and all data were statistically analysed (p laser promoted the reduction of carbonate, the formation of tetracalcium phosphate, as well as the melting and recrystallization of the dentin surface. Laser significantly decreased the area and depth of erosion lesions and altered the optical attenuation coefficient when compared to untreated and APF-gel groups, but the association of APF-gel and laser did not promote an additional effect. Nd:YAG laser irradiation can be a promissory treatment to prevent dentin erosion and the abrasion process. PMID:29389868

The NA48 liquid krypton calorimeter

CERN Document Server

Gorini, B

1997-01-01

The NA48 collaboration goal is to measure the CP violation parameter Re(ɛl/ɛ) at the level of 2 × 10−4. The neutral Kaon decays will be reconstructed by an electromagnetic liquid Krypton calorimeter with fine granularity and a volume almost totally sensible, to obtain excellent position and energy resolution, as well as time resolution. A description of the detector, results from tests of a prototype and the status of the final calorimeter are reported.

Fluoride

Science.gov (United States)

Opalescence® ... Fluoride is used to prevent tooth decay. It is taken up by teeth and helps to strengthen ... and block the cavity-forming action of bacteria. Fluoride usually is prescribed for children and adults whose ...

Study of the spectral and energy characteristics of lasing in the green spectral region by lithium fluoride with radiation color centers

Energy Technology Data Exchange (ETDEWEB)

Voitovich, A.P.; Kalinov, V.S.; Mikhnov, S.A.; Ovseichuk, S.I.

1987-06-01

The spectral and energy characteristics of lasers utilizing lithium fluoride with F2 and F3(+) color centers in transverse and longitudinal pumping schemes are studied. The feasibility of obtaining stable narrow-band radiation in the 510-570 nm range using a selective resonator is demonstrated. Consideration is given to the effect of lithium-fluoride crystal processing by excimer laser radiation at a wavelength of 308 nm on the spectroscopic and lasing characteristics of the F3(+) color center. After this processing, the laser efficiency in the green spectral region increases by more than a factor of two (reaching an efficiency of 14 percent). 7 references.

Acceleration to high velocities and heating by impact using Nike KrF lasera)

Science.gov (United States)

Karasik, Max; Weaver, J. L.; Aglitskiy, Y.; Watari, T.; Arikawa, Y.; Sakaiya, T.; Oh, J.; Velikovich, A. L.; Zalesak, S. T.; Bates, J. W.; Obenschain, S. P.; Schmitt, A. J.; Murakami, M.; Azechi, H.

2010-05-01

The Nike krypton fluoride laser [S. P. Obenschain, S. E. Bodner, D. Colombant, et al., Phys. Plasmas 3, 2098 (1996)] is used to accelerate planar plastic foils to velocities that for the first time reach 1000 km/s. Collision of the highly accelerated deuterated polystyrene foil with a stationary target produces ˜Gbar shock pressures and results in heating of the foil to thermonuclear temperatures. The impact conditions are diagnosed using DD fusion neutron yield, with ˜106 neutrons produced during the collision. Time-of-flight neutron detectors are used to measure the ion temperature upon impact, which reaches 2-3 keV.

Phase-shifted Bragg grating inscription in PMMA microstructured POF using 248 nm UV radiation

DEFF Research Database (Denmark)

Pereira, L.; Pospori, A.; Antunes, Paulo

2017-01-01

In this work we experimentally validate and characterize the first phase-shifted polymer optical fiber Bragg gratings (PS-POFBGs) produced using a single pulse from a 248 nm krypton fluoride laser. A single-mode poly (methyl methacrylate) optical fiber with a core doped with benzyl dimethyl ketal...... for photosensitivity improvement was used. A uniform phase mask customized for 850 nm grating inscription was used to inscribe these Bragg structures. The phase shift defect was created directly during the grating inscription process by placing a narrow blocking aperture in the center of the UV beam. The produced high...

Investigation of diode-laser pumped thulium-doped fluoride lasers

International Nuclear Information System (INIS)

Matos, Paulo Sergio Fabris de

2006-01-01

Tunable lasers emitting around 2.3 mum region are important in many areas, like gas detection, remote sensing and medical applications. Thulium has a large emission spectra around 2.3 mum with demonstrated tuning range of 2.2-2.45 mum using the YLF host. For efficient pump absorption, a high concentration sensitizer like ytterbium can be used. We demonstrate quasi-cw operation of the Yb:Tm:YLF laser, pumped at 960 nm with a 20 W diode bar achieving the highest output power reported so far of 620 mW. Simultaneous pumping of the 2.3 mm Yb:Tm:YLF laser at 685 nm and 960 nm is demonstrated, showing higher slope efficiency than 960 nm alone. Numerical simulations and analytical models show the best ratio of pump power between both wavelengths. (author)

Krypton-85 Monitoring at BfS in Germany and Technical Solutions for Safeguards

International Nuclear Information System (INIS)

Schlosser, C.; Klingberg, F.

2015-01-01

The radioactive noble gas isotope krypton-85 with a half-life of 10.76 years is produced by nuclear fission. The main source of krypton-85 in the atmosphere are releases from reprocessing plants for nuclear fuel in the Northern Hemisphere. This volatile isotope is not retained in such plants and thus a very good indicator for the processing of irradiated nuclear fuel. This includes reprocessing for military purposes. Additionally, Kr-85 could be used as tracer for the validation of Atmospheric Transport Models. The German Federal Office for Radiation Protection (BfS) operates a noble gas laboratory and a global network which continuously monitors the krypton-85 activity concentrations in ground level air since the 1970s. The atmospheric activity concentration has continuously been increasing since the installation of reprocessing plants for nuclear fuels in the early 1950s until 2003. In the first decades it came mostly from military applications and later from civil reprocessing. Since 2003 the atmospheric krypton-85 background level in the Northern Hemisphere is nearly constant with a value of around 1.5 Bq/m 3 in Central Europe. The baseline is superimposed by spikes as a result from discharges of two European reprocessing plants of nuclear fuel, Sellafield and La Hague. The laboratory of the BfS and the techniques used will be presented. Long time series will be discussed and the use of ATM for source location demonstrated. (author)

Immobilization of krypton in a metallic matrix by combined ion implantation and sputtering

International Nuclear Information System (INIS)

Whitmell, D.S.

1980-01-01

With the increase in nuclear power, it may be necessary to contain for 100 to 200 years the radioactive 85 krypton released during fuel reprocessing. The ideal method of immobilizing radioactive materials is in the form of stable, monolithic solids which are resistant to the effects of the environment or accidents, and which can retain the radioactivity under all envisaged conditions. Since krypton is a rare gas, not forming thermally stable compounds, conventional methods of storage are not possible. A process is being developed to immobilize the krypton in the form of small gas bubbles in a metal matrix by implanting the gas into a metal layer from a glow discharge and then burying the implanted layer by sputter deposition. By repeating the process, a thick layer of deposit is built up with the krypton dispersed throughout the matrix as bubbles of diameter less than 20 A. This process offers an ideal form of storage since gas in bubbles is not thermally released until the temperature of the matrix is close to the melting point, and also leakage of gas by corrosion or mechanical damage will be small. A pilot plant is being built in order to demonstrate the process on a scale comparable with that required for a reprocessing plant. The efficiency of the process is dependent upon the amount of gas which can be implanted at low energy into a thin layer and its subsequent retention. (author)

Answers to questions about removing krypton from the Three Mile Island, Unit 2 reactor building. Public information report

International Nuclear Information System (INIS)

1980-05-01

This document presents answers to frequently asked questions about the probable effects of controlled releases of the krypton presently contained within the reactor building of Three Mile Island, Unit 2. Also answered are questions about alternative means for removing the krypton

In vivo PIXE-PIGE study of enhanced retention of fluorine in tooth enamel after laser irradiation

Energy Technology Data Exchange (ETDEWEB)

Demortier, Guy [Department of Physics, University of Namur, 61, rue de Bruxelles, B5000 Namur (Belgium)], E-mail: guy.demortier@tvcablenet.be; Nammour, Samir [Faculty of Medicine, University of Liege, 8, rue Paul Spaak, B-1000 Bruxelles (Belgium)

2008-05-15

The presence of fluoride in tooth enamel reduces the solubility of hydroxylapatite by acid attack. Fluoride presence (even at low concentration) in the oral cavity is efficient against caries process. We propose a new approach of the explanation of the increase of fluoride retention in the tooth enamel when low power laser irradiation is applied after the treatment with fluoride gel (fluoridation). External beam PIGE measurements of fluorine on extracted teeth have been made in order to determine the best sequence of the operations. The laser irradiation after fluoride application is more efficient than the reverse procedure. This observation is in agreement with previous observations that the fluorine penetration in the enamel takes place first in the soft organic material present between the polycrystalline (prismatic) structure before being integrated in the crystalline composition of hydroxylapatite in order to produce fluoro-apatite. As those in vitro measurements do not reflect the whole process in the saliva, in vivo PIGE measurements have been also performed. We have demonstrated, by repeating the PIGE measurements (at least five times at various time intervals) that a significant increase of the fluoride retention took place even 18 months after the unique laser treatment. The complete experimental procedure is described: fluoride application, laser irradiation, PIGE measurements with 2.7 MeV protons (repeated measurements at the same place on the same tooth in order to follow the evolution) and safety tests before in vivo analyses.

Krypton separation from waste gas of a reprocessing plant by low temperature rectification

International Nuclear Information System (INIS)

1987-01-01

6 lectures at this seminar describe and evaluate the results of the research and development work on low temperature krypton separation from the waste gas of the reprocessing of nuclear fuels. They are used for making decisions for the process to be used in the future on a large scale at the Wackersdorf reprocessing plant. 2 further lectures deal with alternatives to this process, which were also developed: the freon washing and low temperature adsorption of krypton. All the lectures were included separately in the INIS and ENERGY databases. (RB) [de

Comparison in the analytical performance between krypton and argon glow discharge plasmas as the excitation source for atomic emission spectrometry.

Science.gov (United States)

Wagatsuma, Kazuaki

2009-04-01

The emission characteristics of ionic lines of nickel, cobalt, and vanadium were investigated when argon or krypton was employed as the plasma gas in glow discharge optical emission spectrometry. A dc Grimm-style lamp was employed as the excitation source. Detection limits of the ionic lines in each iron-matrix alloy sample were compared between the krypton and the argon plasmas. Particular intense ionic lines were observed in the emission spectra as a function of the discharge gas (krypton or argon), such as the Co II 258.033 nm for krypton and the Co II 231.707 nm for argon. The explanation for this is that collisions with the plasma gases dominantly populate particular excited levels of cobalt ion, which can receive the internal energy from each gas ion selectively, for example, the 3d(7)4p (3)G(5) (6.0201 eV) for krypton and the 3d(7)4p (3)G(4) (8.0779 eV) for argon. In the determination of nickel as well as cobalt in iron-matrix samples, more sensitive ionic lines could be found in the krypton plasma rather than the argon plasma. Detection limits in the krypton plasma were 0.0039 mass% Ni for the Ni II 230.299-nm line and 0.002 mass% Co for the Co II 258.033-nm line. However, in the determination of vanadium, the argon plasma had better analytical performance, giving a detection limit of 0.0023 mass% V for the V II 309.310-nm line.

Experimental study of X-ray emission yield in a Filippov-type Plasma Focus operating in neon and neon-krypton mixture

International Nuclear Information System (INIS)

Babazadeh, A.R.; Kiai, S.M.S.; Roshan, M.V.; Emami, M.

2002-01-01

Since the installation of PF-DENA at AEOI about one year ago, we performed quantitative studies of variation of X-ray radiations from a new Filippov-type plasma focus device: Dena (90 kJ, 25 kV, 288 μF). The operating gas was neon at a constant pressure of 1 torr and different pressures of krypton admixture (up to 0.3 torr), with the discharge voltage up to 18 kV. For charging voltage of 17 kV with 41 kJ stored energy and spark gap pressure of 1.2x 10 -2 torr, the maximum soft and little hard X-ray (SXR-HXR) emission is found for the neon, resulting in a total SXR yield of 2 V/shot measured by silicon semiconductor diode detectors. Concerning the effect of krypton admixture, a maximum intensity of SXR radiation has been observed at low krypton pressure that is about 1 V/shot. At higher pressure, the quality of SXR emission decreases down to zero. However, the maximum intensity of the HXR radiation yield in the same pressure range was found to be 2.5 V/shot. By increasing the pressure of krypton up tp 0.3 torr, the results show that the krypton admixture gas generally causes, a decrease of the SXR radiation yield down to zero, whereas, the HXR emission yield carries a maximum value at the optimum pressure of krypton that is about 0.1 torr. Nevertheless, the pressure increments of krypton lead to decreasing in the discharge voltage for the maximum X-ray production. (author)

In Situ Measurement of Atmospheric Krypton and Xenon on Mars with Mars Science Laboratory

Science.gov (United States)

Conrad, P. G.; Malespin, C. A.; Franz, H. B.; Pepin, R. O.; Trainer, M. G.; Schwenzer, S. P.; Atreya, S. K.; Freissinet, C.; Jones, J. H.; Manning, H.;

State-of-the-art ab initio potential energy curve for the krypton atom pair and thermophysical properties of dilute krypton gas.

Science.gov (United States)

Jäger, Benjamin; Hellmann, Robert; Bich, Eckard; Vogel, Eckhard

2016-03-21

A new reference krypton-krypton interatomic potential energy curve was developed by means of quantum-chemical ab initio calculations for 36 interatomic separations. Highly accurate values for the interaction energies at the complete basis set limit were obtained using the coupled-cluster method with single, double, and perturbative triple excitations as well as t-aug-cc-pV5Z and t-aug-cc-pV6Z basis sets including mid-bond functions, with the 6Z basis set being newly constructed for this study. Higher orders of coupled-cluster terms were considered in a successive scheme up to full quadruple excitations. Core-core and core-valence correlation effects were included. Furthermore, relativistic effects were studied not only at a scalar relativistic level using second-order direct perturbation theory, but also utilizing full four-component and Gaunt-effect computations. An analytical pair potential function was fitted to the interaction energies, which is characterized by a depth of 200.88 K with an estimated standard uncertainty of 0.51 K. Thermophysical properties of low-density krypton were calculated for temperatures up to 5000 K. Second and third virial coefficients were obtained from statistical thermodynamics. Viscosity and thermal conductivity as well as the self-diffusion coefficient were computed using the kinetic theory of gases. The theoretical results are compared with experimental data and with results for other pair potential functions from the literature, especially with those calculated from the recently developed ab initio potential of Waldrop et al. [J. Chem. Phys. 142, 204307 (2015)]. Highly accurate experimental viscosity data indicate that both the present ab initio pair potential and the one of Waldrop et al. can be regarded as reference potentials, even though the quantum-chemical methods and basis sets differ. However, the uncertainties of the present potential and of the derived properties are estimated to be considerably lower.

Present and future potential of krypton-85 for the detection of clandestine reprocessing plants for treaty verification.

Science.gov (United States)

Schoeppner, Michael; Glaser, Alexander

2016-10-01

Burnup calculations are applied to determine the amount of krypton-85 that is produced during the irradiation of nuclear fuel. Since krypton-85 is most likely released into the atmosphere during reprocessing to separate plutonium, atmospheric transport modeling is used to calculate the worldwide distribution of krypton-85 concentrations stemming from emissions from declared reprocessing plants. The results are the basis for scenarios in which emissions from clandestine reprocessing facilities have to be detected against various background levels. It is concluded that today's background imposes heavily on the ability to detect small and medium plutonium separation rates; only high separation rates of 1 SQ per week and higher have a chance to be detected with feasible outlay. A fixed network of monitoring stations seems too costly; instead the high number of samples that are required rather calls for mobile sampling procedures, where air samples are collected at random locations over the world and are analyzed in regional laboratories for their krypton-85 concentration. Further, it is argued that krypton-85 emissions from declared reprocessing activities have to be significantly lowered to enable a worldwide verification of the absence of even smaller clandestine reprocessing. For each scenario the number of samples that have to be taken for probable detection is calculated. Copyright © 2016 Elsevier Ltd. All rights reserved.

Other Fluoride Products

Science.gov (United States)

... Private Wells Infant Formula Fluorosis Public Health Service Recommendation Water Operators & Engineers Water Fluoridation Additives Shortages of Fluoridation Additives Drinking Water Pipe Systems CDC-Sponsored Water Fluoridation Training Links to Other ...

In Vitro Evaluation of Dentin Hydraulic Conductance After 980 nm Diode Laser Irradiation.

Science.gov (United States)

Rizzante, Fabio A P; Maenosono, Rafael M; Duarte, Marco A H; Furuse, Adilson Y; Palma-Dibb, Regina G; Ishikiriama, Sérgio K

2016-03-01

Dentin hypersensitivity treatments are based on the physical obliteration of the dentinal tubules to reduce hydraulic conductance. The aim of the present study is to evaluate the hydraulic conductance of bovine root dentin after irradiation with a 980-nm diode laser, with or without associated fluoride varnish. Sixty bovine root dentin specimens were divided into six groups (n = 10 in each group): G1, G3, and G5 (0.5 W, 0.7 W, and 1 W diode laser, respectively); G2, G4, and G6 (fluoride varnish application + 0.5 W, 0.7 W, and 1 W diode laser, respectively). The dentin hydraulic conductance was evaluated at four time periods with a fluxmeter: 1) with smear layer, 2) after 37% phosphoric acid etching, 3) after the treatments, and 4) after 6% citric acid challenge. After the dentinal fluid flow measurements, specimens were also evaluated for mineral composition using energy dispersive X-ray spectroscopy (EDS). Analysis demonstrated a better result with increased irradiation power (P diode laser irradiation was associated with the application of fluoride varnish (P laser irradiation, the 1 W group was superior when compared with the 0.5 W and 0.7 W irradiated groups immediately after treatment (P laser treatments. Laser irradiation of exposed dentin promoted significant reduction in the dentin hydraulic conductance, mainly with higher energy densities and association with fluoride varnish.

Generalized oscillator strengths for some higher valence-shell excitations of krypton atom

Institute of Scientific and Technical Information of China (English)

2007-01-01

The valence-shell excitations of krypton atom have been investigated by fast electron impact with an angle-resolved electron-energy-loss spectrometer. The generalized oscillator strengths for some higher mixed valence-shell excitations in 4d, 4f, 5p, 5d, 6s, 6p, 7s ← 4p of krypton atom have been determined. Their profiles are discussed, and the generalized oscillator strengths for the electric monopole and quadrupole excitations in 5p ← 4p are compared with the calculations of Amusia et al. (Phys. Rev. A 67 022703 (2003)). The differences between the experimental results and theoretical calculations show that more studies are needed.

Industrial fluoride pollution: chronic fluoride poisoning in Cornwall Island cattle

Energy Technology Data Exchange (ETDEWEB)

Krook, L.; Maylin, G.A.

1979-04-01

An aluminum plant on the south bank of the St. Lawrence River, southwest of Cornwall Island, Ontario, Canada, has emitted 0.816 metric tons of fluoride daily since 1973. Considerably higher amounts were emitted from 1959 to 1973. The plant was designated as the major source of fluoride emissions impacting on Cornwall Island. Cattle located on this island showed signs of chronic fluoride poisoning. This poisoning was manifested clinically by stunted growth and dental fluorosis to a degree of severe interference with drinking and mastication. This Cornwall Island herds study indicates that the established tolerance level of fluoride for performance of dairy and beef cattle is not valid since the tolerance level was set based on experiments with healthy calves which were exposed to dietary fluoride from 3 to 4 months of age and not on cattle which were chronically exposed to fluoride from conception to death. 56 references.

Interdiffusion of krypton and xenon in high-pressure helium

International Nuclear Information System (INIS)

Campana, R.J.; Jensen, D.D.; Epstein, B.D.; Hudson, R.G.; Baldwin, N.L.

1980-01-01

The interdiffusion of gaseous fission products in high-pressure helium is an important factor in the control of radioactivity in gas-cooled fast breeder reactors (GCFRs). As presently conceived, GCFRs use pressure-equalized and vented fuel in which fission gases released from the solid matrix oxide fuel are transported through the fuel rod interstices and internal fission product traps to the fuel assembly vents, where they are swept away to external traps and storage. Since the predominant transport process under steady-state operating conditions is interdiffusion of gaseous fission products in helium, the diffusion properties of krypton-helium and xenon-helium couples have been measured over the range of GCFR temperature and pressure conditions ( -1 ) and expected temperature dependence to the 1.66 power (Tsup(1.66)) at lower pressures and temperatures. Additional work is in progress to measure the behaviour of the krypton-helium and xenon-helium couples in GCFR fuel rod charcoal delay traps. (author)

Separation, storage, and disposal of krypton-85: status and projects

Energy Technology Data Exchange (ETDEWEB)

Laser, M.

1976-09-15

Despite the relatively small impact of ⁸⁵Kr to man the separation of fission krypton from the off-gas of fuel reprocessing plants must be taken into account. Combined with other advantages also in power reactor stations the retention of ⁸⁵Kr seems to be attractive. Cryogenic processes are favored worldwide, because the technology has been well proven during several decades in air liquefaction and separation plants. Relatively small modifications must be made to adjust these processes to fission gas separation plants. Some fundamental data however are necessary for the design of a plant. Besides cryogenic processes a liquid adsorption for reprocessing off-gases and charcoal adsorption processes for reactor off-gas are under discussion. The retained krypton can be stored under air or water cooling in usual pressurized steel cylinders. However, legal problems may arise. The steel cylinders can be stored in engineered storage facilities for an intermediate period or finally. In Europe, however, the final storage will be questionable. Therefore, the dumping of ⁸⁵Kr into the deep sea has been proposed. For this reason a revision of the London Convention is necessary, because the dumping of ⁸⁵/Kr has not been specified. The IAEA as competent authority is asked to define the conditions for dumping. Injection of krypton containing gases into porous geologic strata may also be possible, if a very small release can be guaranteed.

Climate risks by radioactive krypton-85 from nuclear fission. Atmospheric-electrical and air-chemical effects of ionizing radiation in the atmosphere

International Nuclear Information System (INIS)

Kollert, R.

1994-01-01

The study shows that krypton-85 from nuclear fission enhances air ionization and, thus, interferes with the atmospheric-electrical system and the water balance of the earth atmosphere. This is reason for concern: There are unforeseeable effects for weather and climate if the krypton-85 content of the earth atmosphere continues to rise. There may be a krypton-specific greenhouse effect and a collapse of the natural atmospheric-electrical field. In addition, human well-being may be expected to be impaired as a result of the diminished atmospheric-electrical field. There is also the risk of radiochemical actions and effects caused-by krypton-85-containing plumes in other air-borne pollutants like the latters' transformation to aggressive oxidants. This implies radiation smog and more acid rain in the countries exposed. This study summarizes findings gained in these issues by various sciences, analyses them and elaborates hypotheses on the actions and effects of krypton-85 on the air, the atmosphere and the climate. (orig./HP) [de

S-process krypton of variable isotopic composition in the Murchison meteorite

Science.gov (United States)

Ott, Urlich; Begemann, Friedrich; Yang, Yongmann; Epstein, Samuel

1988-01-01

Data are reported which, for the first time, permit the derivation of the full isotopic spectrum of s-process krypton with reasonable precision. It is shown that this s-Kr in a residue from the Murchison meteorite did not originate in one single s-process but rather is a mixture of contributions from stellar environments where the density of free neutrons was not the same. The astrophysical conditions under which this krypton was produced were distinct from those that have been invoked to explain the solar system s-process abundance. Similar to the C-13-rich carbon component in an aliquot of the same residue, the s-process Kr from different astrophysical sites has retained its identity during the accumulation and subsequent history of the meteorite.

S-process krypton of variable isotopic composition in the Murchison meteorite

International Nuclear Information System (INIS)

Ott, U.; Begemann, F.; Yang, J.; Epstein, S.

1988-01-01

We report data that allow us to derive with reasonable precision the full isotopic spectrum of s-process krypton. We show that this s-Kr in a residue from Murchison meteorite did not originate in one single s-process but rather is a mixture of contributions from stellar environments where the density of free neutrons was not the same. The astrophysical conditions under which this krypton has been produced were distinct from those that have been invoked to explain the Solar System s-process abundance. Similar to the 13 C-rich carbon component in an aliquot of the same residue, the s-process Kr from different astrophysical sites has retained its identify during the accumulation and subsequent history of the meteorite. (author)

Krypton tagging velocimetry in a turbulent Mach 2.7 boundary layer

Science.gov (United States)

Zahradka, D.; Parziale, N. J.; Smith, M. S.; Marineau, E. C.

2016-05-01

The krypton tagging velocimetry (KTV) technique is applied to the turbulent boundary layer on the wall of the "Mach 3 Calibration Tunnel" at Arnold Engineering Development Complex (AEDC) White Oak. Profiles of velocity were measured with KTV and Pitot-pressure probes in the Mach 2.7 turbulent boundary layer comprised of 99 % {N}2/1 % Kr at momentum-thickness Reynolds numbers of {Re}_{\\varTheta }= 800, 1400, and 2400. Agreement between the KTV- and Pitot-derived velocity profiles is excellent. The KTV and Pitot velocity data follow the law of the wall in the logarithmic region with application of the Van Driest I transformation. The velocity data are analyzed in the outer region of the boundary layer with the law of the wake and a velocity-defect law. KTV-derived streamwise velocity fluctuation measurements are reported and are consistent with data from the literature. To enable near-wall measurement with KTV (y/δ ≈ 0.1-0.2), an 800-nm longpass filter was used to block the 760.2-nm read-laser pulse. With the longpass filter, the 819.0-nm emission from the re-excited Kr can be imaged to track the displacement of the metastable tracer without imaging the reflection and scatter from the read-laser off of solid surfaces. To operate the Mach 3 AEDC Calibration Tunnel at several discrete unit Reynolds numbers, a modification was required and is described herein.

Study of structural and transport properties of argon, krypton, and their binary mixtures at different temperatures.

Science.gov (United States)

Ghimire, Sunil; Adhikari, Narayan Prasad

2017-03-01

Molecular dynamics simulation of argon, krypton, and their binary mixtures were performed at different temperatures and constant pressure (P = 1.013 bar) using GROMACS - Groningen Machine for Chemical Simulations. The gases are modeled by Lennard-Jones pair potential, with parameters taken from the literature. The study of radial distribution functions (RDFs) shows a single peak which indicates that there is no packing effect in gaseous state for argon, krypton, and their binary mixtures. The self-diffusion coefficients of argon and krypton is determined by using mean-square displacement(MSD) method and the mutual diffusion coefficients of binary mixtures are determined using Darken's relation. The values of simulated diffusion coefficients are compared with their corresponding theoretical values, numerical estimation, and experimental data. A good agreement between these sets of data is found. The diffusion coefficients obey Arrhenius behavior to a good extent for both pure components and binary mixtures. The values of simulated diffusion coefficient are used to estimate viscosities and thermal conductivities which agree with theoretical values, numerical estimation, and experimental data within 10 %. These results support that the LJ potential is sufficient for description of molecular interactions in argon and krypton.

Determination of SO2 in the atmosphere using radioactive iodine kryptonate as impregnation medium of chromatographic paper

International Nuclear Information System (INIS)

Pruzinec, J.

1975-01-01

Chromatographic paper was impregnated with radioiodine kryptonate using the macrodiffusion technique. The decrease with time of the activity of the kryptonate-impregnated paper exposed to SO 2 -contaminated air was measured. From the decrease in chromatographic paper activity, the concentration of SO 2 was determined in the range 300 to 700 ppm. (A.K.)

Evaluation of diode laser and stannous fluoride in the treatment of root sensitivity after access flap surgery: Randomized controlled clinical trial.

Science.gov (United States)

Raut, Chetan Purushottam; Sethi, Kunal Sunder; Kohale, Bhagyashree; Mamajiwala, Alefiya; Warang, Ayushya

2018-01-01

Postsurgical root sensitivity has always been an enigma to the periodontists. There is a plethora of evidence suggesting the presence of root sensitivity following periodontal flap surgical procedures. Thus, the aim of the present study was to compare and evaluate the effect of low-power diode lasers with and without topical application of stannous fluoride (SnF 2 ) gel in the treatment of root sensitivity and also evaluate whether laser creates any placebo effect in the control group or not. Thirty patients participated in this study and 99 teeth were included. Root sensitivity was assessed for all groups with a Verbal Rating Scale (VRS). For each patient, the teeth were randomized into three groups. In the test Group I, sensitive teeth were treated with SnF 2 and diode laser. In the test Group II, sensitive teeth were irradiated with laser only. In the control group, no treatment was performed. The mean ± standard deviation (SD) score for VRS and Visual Analog Scale at baseline was not statistically significant ( P > 0.05) between the three groups. After 15 min, statistical significant difference was seen in test Group I and test Group II, although no difference was found in the control group. At 15 th day and 30 th day, the mean ± SD scores were statistically significant ( P diode lasers alone and in combination with 0.4% SnF 2 was effective in the treatment of root sensitivity after access flap surgery.

Urinary fluoride excretion in preschool children after intake of fluoridated milk and use of fluoride-containing toothpaste

DEFF Research Database (Denmark)

Norman, M; Twetman, S; Hultgren Talvilahti, A

2017-01-01

Objective: To assess the urinary fluoride excretion in preschool children after drinking fluoridated milk with 0.185 mg F and 0.375 mg F and to study the impact of use of fluoride toothpaste. Basic research design: Double-blind cross-over study. Participants: Nine healthy children, 2.5-4.5 years...

Oral fluoride retention after professional topical application in children with caries activity: comparison between 1.23% fluoride foam and fluoride gel

Directory of Open Access Journals (Sweden)

Cecília Claudia Costa Ribeiro

2008-01-01

Full Text Available Objective: This study evaluated fluoride retention in the saliva of children with caries activity after topical fluoride application in the form of gel and foam. Methods: A cross-sectional, blind and randomized study, conducted with ten caries-active children aged between 8 and 10 years, in two stage, with a washout interval of two weeks between them. The treatments consisted of: a application of 2mL acidulated phosphate fluoride of the gel type in a mold and b application of 2mL acidulated phosphate fluoride of the foam type in a mold. After the washout, the treatments were inverted. Non-stimulated saliva was collected from the children at the times of 5, 15, 30 and 60 minutes after topical fluoride application. For statistical analysis the Student’s-t test was used, with a level of significance of 5%. Results: Saliva analysis was performed using a fluoride-specific electrode (ISE25F/ Radiometer, Copenhagen, Denmark at the Aquatic Science Center of the Federal University of Marana, which revealed differences after 5 minutes (p=0.0055 and 15 minutes (p=0.0208. The topical application of fluoride in the gel form revealed a higher concentration of fluoride in the saliva. Conclusion: There were differences in the retention of fluoride in the saliva of children with caries activity after the topical application of fluoride gel and the topical application of fluoride foam after 5 and 15 minutes of their application. The topical application of fluoride foam is recommended, on the basis of the lower probability of toxicity during its use.

Sub-ablative Er,Cr:YSGG laser irradiation under all-ceramic restorations: effects on demineralization and shear bond strength.

Science.gov (United States)

Bağlar, Serdar

2018-01-01

This study evaluated the caries resistant effects of sub-ablative Er,Cr:YSGG laser irradiation alone and combined with fluoride in comparison with fluoride application alone on enamel prepared for veneer restorations. And also, evaluated these treatments' effects on the shear bond strength of all-ceramic veneer restorations. One hundred and thirty-five human maxillary central teeth were assigned to groups of 1a-control, 1b-laser treated, 1c-fluoride treated, 1d-laser + fluoride treated for shear bond testing and to groups of 2a-positive control(non-demineralised), 2b-laser treated, 2c-fluoride treated, 2d-laser + fluoride treated, 2e-negative control (demineralised) for microhardness testing (n = 15, N = 135). Demineralisation solutions of microhardness measurements were used for the ICP-OES elemental analysis. The parameters for laser irradiation were as follows: power output, 0.25 W; total energy density, 62.5 J/cm 2 and energy density per pulse, 4.48 J/cm 2 with an irradiation time of 20 s and with no water cooling. Five percent NaF varnish was used as fluoride preparate. ANOVA and Tukey HSD tests were performed (α = 5%). Surface treatments showed no significant effects on shear bond strength values (p = 0.579). However, significant differences were found in microhardness measurements and in elemental analysis of Ca and P amounts (p < 0.01). Surface-treated groups showed significantly high VNH values and significantly low ICP-OES values when compared with non-treated (-control) group while there were no significance among surface-treated groups regarding VHN and ICP-OES values. Sub-ablative Er,Cr:YSGG treatment alone or combined with fluoride is as an effective method as at least fluoride alone for preventing the prepared enamel to demineralization with no negative effect on shear bond strength.

Eukaryotic resistance to fluoride toxicity mediated by a widespread family of fluoride export proteins.

Science.gov (United States)

Li, Sanshu; Smith, Kathryn D; Davis, Jared H; Gordon, Patricia B; Breaker, Ronald R; Strobel, Scott A

2013-11-19

Fluorine is an abundant element and is toxic to organisms from bacteria to humans, but the mechanisms by which eukaryotes resist fluoride toxicity are unknown. The Escherichia coli gene crcB was recently shown to be regulated by a fluoride-responsive riboswitch, implicating it in fluoride response. There are >8,000 crcB homologs across all domains of life, indicating that it has an important role in biology. Here we demonstrate that eukaryotic homologs [renamed FEX (fluoride exporter)] function in fluoride export. FEX KOs in three eukaryotic model organisms, Neurospora crassa, Saccharomyces cerevisiae, and Candida albicans, are highly sensitized to fluoride (>200-fold) but not to other halides. Some of these KO strains are unable to grow in fluoride concentrations found in tap water. Using the radioactive isotope of fluoride, (18)F, we developed an assay to measure the intracellular fluoride concentration and show that the FEX deletion strains accumulate fluoride in excess of the external concentration, providing direct evidence of FEX function in fluoride efflux. In addition, they are more sensitive to lower pH in the presence of fluoride. These results demonstrate that eukaryotic FEX genes encode a previously unrecognized class of fluoride exporter necessary for survival in standard environmental conditions.

April 25, 2003, FY2003 Progress Summary and FY2002 Program Plan, Statement of Work and Deliverables for Development of High Average Power Diode-Pumped Solid State Lasers,and Complementary Technologies, for Applications in Energy and Defense

International Nuclear Information System (INIS)

Meier, W; Bibeau, C

2005-01-01

The High Average Power Laser Program (HAPL) is a multi-institutional, synergistic effort to develop inertial fusion energy (IFE). This program is building a physics and technology base to complement the laser-fusion science being pursued by DOE Defense programs in support of Stockpile Stewardship. The primary institutions responsible for overseeing and coordinating the research activities are the Naval Research Laboratory (NRL) and Lawrence Livermore National Laboratory (LLNL). The current LLNL proposal is a companion document to the one submitted by NRL, for which the driver development element is focused on the krypton fluoride excimer laser option. The NRL and LLNL proposals also jointly pursue complementary activities with the associated rep-rated laser technologies relating to target fabrication, target injection, final optics, fusion chamber, target physics, materials and power plant economics. This proposal requests continued funding in FY03 to support LLNL in its program to build a 1 kW, 100 J, diode-pumped, crystalline laser, as well as research into high gain fusion target design, fusion chamber issues, and survivability of the final optic element. These technologies are crucial to the feasibility of inertial fusion energy power plants and also have relevance in rep-rated stewardship experiments. The HAPL Program pursues technologies needed for laser-driven IFE. System level considerations indicate that a rep-rated laser technology will be needed, operating at 5-10 Hz. Since a total energy of ∼2 MJ will ultimately be required to achieve suitable target gain with direct drive targets, the architecture must be scaleable. The Mercury Laser is intended to offer such an architecture. Mercury is a solid state laser that incorporates diodes, crystals and gas cooling technologies

Combustion driven NF3 chemical laser

International Nuclear Information System (INIS)

1975-01-01

Stable, inert, non-corrosive nitrogen trifluoride gas and an inorganic source of hydrogen or deuterium gas are used as reactants in a compact combustion driven chemical laser. Nitrogen trifluoride is introduced into the combustion chamber of a chemical laser together with a hydrogen source selected from hydrogen, hydrazine, ammonia, acetylene, or benzene and the deuterated isotopes thereof and an optional inert diluent gas wherein the nitrogen trifluoride and the hydrogen- or deuterium-source gas hypergolically reacted upon heating to initiation temperature. Dissociated products from the reaction pass into a laser cavity at supersonic velocities where they are reacted with a source gas which is the isotopic opposite of the gas introduced into the combustor and which has been heated by regenerative cooling. Excited molecules of hydrogen fluoride or deuterium fluoride produce laser radiation which leaves the optical resonator cavity transversely to the flow of gases

A survey of methods for separating and immobilizing krypton-85 arising from a nuclear fuel reprocessing plant

International Nuclear Information System (INIS)

Taylor, P.

1990-12-01

This report reviews the literature on methods to separate and immobilize krypton-85 arising from dissolution or prior treatment of nuclear fuel in a reprocessing plant. It was prepared as part of a broader review of fuel reprocessing waste management methods that might find future applications in Canada. Cryogenic distillation is the most fully demonstrated method of separation of krypton from off-gases, but it is complex. In particular, it requires pretreatment of the gas stream to eliminate several other components before the final distillation. The most highly developed alternative process is fluorocarbon adsorption, while several other processes have been investigated on a bench scale. The simplest method of storing radioactive krypton is in compressed-gas cylinders, but the risks of accidental release are increased by the corrosive nature of the decay product, rubidium. Encapsulation in either a metal matrix or a hydrothermally vitrified zeolite appears to offer the most secure immobilization of krypton. Processes for both types of material have been demonstrated inactively on a scale approaching that required for treatment of off-gases from a commercial-scale fuel reprocessing plant. Low-operating temperatures and pressures of the metal encapsulation process, compared with encapsulation in zeolites, represent a definite advantage, but electrical power requirements for the former process are relatively high. It appears that suitable technology is available for separation and immobilization of radioactive krypton, should the need arise in Canada in the future

No Calcium-Fluoride-Like Deposits Detected in Plaque Shortly after a Sodium Fluoride Mouthrinse

OpenAIRE

Vogel, G.L.; Tenuta, L.M.A.; Schumacher, G.E.; Chow, L.C.

2010-01-01

Plaque ‘calcium-fluoride-like’ (CaF2-like) and fluoride deposits held by biological/bacterial calcium fluoride (Ca-F) bonds appear to be the source of cariostatic concentrations of fluoride in plaque fluid. The aim of this study was to quantify the amounts of plaque fluoride held in these reservoirs after a sodium fluoride rinse. 30 and 60 min after a 228 μg/g fluoride rinse, plaque samples were collected from 11 volunteers. Each sample was homogenized, split into 2 aliquots (aliquots 1 and 2...

Urinary fluoride output in children following the use of a dual-fluoride varnish formulation

Directory of Open Access Journals (Sweden)

Kelly Polido Kaneshiro Olympio

2009-06-01

Full Text Available OBJECTIVE: This study evaluated the bioavailability of fluoride after topical application of a dual-fluoride varnish commercially available in Brazil, when compared to DuraphatTM. MATERIAL AND METHODS: The urinary fluoride output was evaluated in seven 5-year-old children after application of the fluoride varnishes, in two different phases. In the first phase (I, children received topical application of the fluoride varnish Duofluorid XII (2.92% fluorine, calcium fluoride + 2.71% fluorine, sodium fluoride, FGM TM. After 1-month interval (phase II, the same amount (0.2 mL of the fluoride varnish Duraphat (2.26% fluorine, sodium fluoride, ColgateTM was applied. Before each application all the volunteers brushed their teeth with placebo dentifrice for 7 days. Urinary collections were carried out 24 h prior up to 48 h after the applications. Fluoride intake from the diet was also estimated. Fluoride concentration in diet samples and urine was analyzed with the fluoride ion-specific electrode and a miniature calomel reference electrode coupled to a potentiometer. Data were tested by ANOVA and Tukey's post hoc test (p<0.05. RESULTS: There were significant differences in the urinary fluoride output between phases I and II. The use of Duofluorid XII did not significantly increase the urinary fluoride output, when compared to baseline levels. The application of Duraphat caused a transitory increase in the urinary fluoride output, returning to baseline levels 48 h after its use. CONCLUSIONS: The tested varnish formulation, which has been shown to be effective in in vitro studies, also can be considered safe.

Classification of x-ray spectra of 2-3 transitions in the Ne-like and Na-like isoelectronic sequences of the elements from krypton to molybdenum

International Nuclear Information System (INIS)

Gordon, H.; Hobby, M.G.; Peacock, N.J.; Cowan, R.D.

1979-01-01

Plasmas produced by the laser irradiation of solid targets and in a plasma focus device have been employed as sources of x-ray spectra of the elements Kr(Z = 36)-Mo(Z = 42). The Ne-like isoelectronic sequence has been investigated by comparing observed wavelengths with ab initio atomic structure calculations and isoelectronic interpolation. Previous identifications in Ne-like ions have been extended to krypton, rubidium and strontium. The Na-like satellite structure of these elements has also been studied and a detailed classification of these satellites is presented. (author)

Nd:YAG laser in caries prevention: a clinical study

International Nuclear Information System (INIS)

Boari, Heloisa Gomes Dimiranda

2000-01-01

The caries prevention by using laser irradiation has been investigated during the last 30 years. The Nd: YAG laser associated with acidulated phosphate fluoride has been shown as a very promising technique for enamel caries prevention. The aim of this work was to clinically evaluate the efficiency of Nd: YAG laser associated with acidulated phosphate fluoride in pit and fissure caries prevention of children and adolescents. In this work it was determined the dye that enhance the effect of Nd: YAG laser in enamel. It was selected 242 pre-molar and molar teeth from 33 children and adolescents, aged from 7 to 15 years old. The selected teeth were free from caries or decalcification marks (active white marks) to the clinical and radiographic exams. The teeth were divided into two groups: the first group was laser irradiated and their homologous remained as a control. The right side teeth were dye-assisted Nd:YAG laser irradiated. The dye solution was a moisture of dust coal and equal parts of water and alcohol. The irradiation conditions were 60 mJ/10 Hz, optical fiber in contact mode, with diameter of 300 μm, resulting in an energy density of 84,9 J/cm 2 . The oclusal surface of the teeth was completely irradiated, specially on the slopes and in the deepest part of the pits and fissures. This procedure was repeated three times. In the sequence it was applied the acidulated phosphate fluoride for 4 minutes. On the left side teeth - control group- only acidulated phosphate fluoride was applied for the same time. The final examination considered the presence of caries and active white marks after a period of one year. There were statistical significant differences (p < 0.01) between the lased + fluoride group and the non irradiated group. The present study concluded that the technique used in this work can be an alternative clinical method for caries prevention. (author)

Fluoride Rinses, Gels and Foams

DEFF Research Database (Denmark)

Twetman, Svante; Keller, Mette K

2016-01-01

AIM: The aim of this conference paper was to systematically review the quality of evidence and summarize the findings of clinical trials published after 2002 using fluoride mouth rinses, fluoride gels or foams for the prevention of dental caries. METHODS: Relevant papers were selected after...... (6 on fluoride mouth rinse, 10 on fluoride gel and 3 on fluoride foam); 6 had a low risk of bias while 2 had a moderate risk. All fluoride measures appeared to be beneficial in preventing crown caries and reversing root caries, but the quality of evidence was graded as low for fluoride mouth rinse......, moderate for fluoride gel and very low for acidulated fluoride foam. No conclusions could be drawn on the cost-effectiveness. CONCLUSIONS: This review, covering the recent decade, has further substantiated the evidence for a caries-preventive effect of fluoride mouth rinse, fluoride gel and foam...

Experimental studies on the krypton absorption in liquid CO2 (KALC) process

International Nuclear Information System (INIS)

Glass, R.W.; Beaujean, H.W.R.; Fowler, V.L.; Gilliam, T.M.; Inman, D.J.; Levins, D.M.

1976-01-01

Results are presented for a series of experiments to quantify krypton removal from simulated High-Temperature Gas-Cooled Reactor reprocessing off-gas by the KALC process. The Experimental Engineering Section Off-Gas Decontamination Facility used in the campaign provides engineering-scale experiments with nominal gas and liquid flows of 5 scfm and 0.5 gpm respectively. Equilibrium and nonequilibrium mass transfer experiments for the CO 2 --O 2 --Kr system are described. Data analysis indicates values of HTU for krypton on the order of 0.5 ft for decontamination factors from 100 to 10,000. Recent flooding information for the packed columns is combined with previous data and is shown to be well represented by an empirical flooding equation

High-Intensity Femtosecond Laser Interaction with Rare Gas Clusters

Institute of Scientific and Technical Information of China (English)

林亚风; 钟钦; 曾淳; 陈哲

2001-01-01

With a 45 fs multiterawatt 790 nm laser system and jets of argon and krypton atomic clusters, a study of the interaction of fs intense laser pulses with large size rare gas dusters was conducted. The maximum laser intensity of about 7 × 1016 W/cm2 and dusters composed of thousands of atoms which were determined through Rayleigh scattering measurements were involved inthe experiments. On the one hand, the results indicate that the interaction is strongly cluster size dependent. The stronger the interaction, the larger the clusters are. On the other hand, a saturation followed by a drop of the energy of ions ejected from the interaction will occur when the laser intensity exceeds a definite value for clusters of a certain size.

The cariostatic mechanisms of fluoride

Directory of Open Access Journals (Sweden)

Kata Rošin-Grget

2013-11-01

Full Text Available This article discusses the possible cariostatic mechanisms of the action of fluoride. In the past, fluoride inhibition of caries was ascribed to reduced solubility of enamel due to incorporation of fluoride (F– into the enamel minerals. The present evidence from clinical and laboratory studies suggests that the caries-preventive mode of action of fluoride is mainly topical. There is convincing evidence that fluoride has a major effect on demineralisation and remineralisation of dental hard tissue. The source of this fluoride could either be fluorapatite (formed due to the incorporation of fluoride into enamel or calcium fluoride (CaF2-like precipitates, which are formed on the enamel and in the plaque after application of topical fluoride. Calcium fluoride deposits are protected from rapid dissolution by a phosphate –protein coating of salivary origin. At lower pH, the coating is lost and an increased dissolution rate of calcium fluoride occurs. The CaF2, therefore, act as an efficient source of free fluoride ions during the cariogenic challenge. The current evidence indicates that fluoride has a direct and indirect effect on bacterial cells, although the in vivo implications of this are still not clear. Conclusion. A better understanding of the mechanisms of the action of fluoride is very important for caries prevention and control. The effectiveness of fluoride as a cariostatic agent depends on the availability of free fluoride in plaque during cariogenic challenge, i.e. during acid production. Thus, a constant supply of low levels of fluoride in biofilm/saliva/dental interference is considered the most beneficial in preventing dental caries.

The cariostatic mechanisms of fluoride.

Science.gov (United States)

Rošin-Grget, Kata; Peroš, Kristina; Sutej, Ivana; Bašić, Krešimir

2013-11-01

This article discusses the possible cariostatic mechanisms of the action of fluoride. In the past, fluoride inhibition of caries was ascribed to reduced solubility of enamel due to incorporation of fluoride (F-) into the enamel minerals. The present evidence from clinical and laboratory studies suggests that the caries-preventive mode of action of fluoride is mainly topical. There is convincing evidence that fluoride has a major effect on demineralisation and remineralisation of dental hard tissue. The source of this fluoride could either be fluorapatite (formed due to the incorporation of fluoride into enamel) or calcium fluoride (CaF2)-like precipitates, which are formed on the enamel and in the plaque after application of topical fluoride. Calcium fluoride deposits are protected from rapid dissolution by a phosphate -protein coating of salivary origin. At lower pH, the coating is lost and an increased dissolution rate of calcium fluoride occurs. The CaF2, therefore, act as an efficient source of free fluoride ions during the cariogenic challenge. The current evidence indicates that fluoride has a direct and indirect effect on bacterial cells, although the in vivo implications of this are still not clear. A better understanding of the mechanisms of the action of fluoride is very important for caries prevention and control. The effectiveness of fluoride as a cariostatic agent depends on the availability of free fluoride in plaque during cariogenic challenge, i.e. during acid production. Thus, a constant supply of low levels of fluoride in biofilm/saliva/dental interference is considered the most beneficial in preventing dental caries. Copyright © 2013 by Academy of Sciences and Arts of Bosnia and Herzegovina.

Hyperpolarized krypton-83 as a contrast agent for magnetic resonance imaging.

Science.gov (United States)

Pavlovskaya, Galina E; Cleveland, Zackary I; Stupic, Karl F; Basaraba, Randall J; Meersmann, Thomas

2005-12-20

For the first time, magnetic resonance imaging (MRI) with hyperpolarized (hp) krypton-83 (83Kr) has become available. The relaxation of the nuclear spin of 83Kr atoms (I = 9/2) is driven by quadrupolar interactions during brief adsorption periods on surrounding material interfaces. Experiments in model systems reveal that the longitudinal relaxation of hp 83Kr gas strongly depends on the chemical composition of the materials. The relaxation-weighted contrast in hp 83Kr MRI allows for the distinction between hydrophobic and hydrophilic surfaces. The feasibility of hp 83Kr MRI of airways is tested in canine lung tissue by using krypton gas with natural abundance isotopic distribution. Additionally, the influence of magnetic field strength and the presence of a breathable concentration of molecular oxygen on longitudinal relaxation are investigated.

Absorption process for removing krypton from the off-gas of an LMFBR fuel reprocessing plant

International Nuclear Information System (INIS)

Stephenson, M.J.; Dunthorn, D.I.; Reed, W.D.; Pashley, J.H.

1975-01-01

The Oak Ridge Gaseous Diffusion Plant selective absorption process for the collection and recovery of krypton and xenon is being further developed to demonstrate, on a pilot scale, a fluorocarbon-based process for removing krypton from the off-gas of an LMFBR fuel reprocessing plant. The new ORGDP selective absorption pilot plant consists of a primary absorption-stripping operation and all peripheral equipment required for feed gas preparation, process solvent recovery, process solvent purification, and krypton product purification. The new plant is designed to achieve krypton decontamination factors in excess of 10 3 with product concentration factors greater than 10 4 while processing a feed gas containing typical quantities of common reprocessing plant off-gas impurities, including oxygen, carbon dioxide, nitrogen oxides, water, xenon, iodine, and methyl iodide. Installation and shakedown of the facility were completed and some short-term tests were conducted early this year. The first operating campaign using a simulated reprocessing plant off-gas feed is now underway. The current program objective is to demonstrate continuous process operability and performance for extended periods of time while processing the simulated ''dirty'' feed. This year's activity will be devoted to routine off-gas processing with little or no deliberate system perturbations. Future work will involve the study of the system behavior under feed perturbations and various plant disturbances. (U.S.)

Krypton 81m and xenon 133 for complementary ventilation imaging in pulmonary perfusion studies: a clinical comparison. Chapter 12

International Nuclear Information System (INIS)

Weber, P.M.; Remedios, L.V.dos.

1978-01-01

Twenty-four patients with suspected pulmonary embolism were studied to determine the relative usefulness of 133 Xe and 81 Krsup(m) as indicators of pulmonary ventilation in complementing perfusion studies. In most cases, where krypton produced results superior to xenon, this could be attributed to better resolution of the 190 keV photon and to the fact that multiple views could be obtained, with each view paired precisely with a corresponding perfusion image, the direct result of the ease of use of krypton and its short 13 second half-life. This was well demonstrated in both of the patients with presumed pulmonary embolism and co-existing other pulmonary disease in which the results with xenon and krypton differed. In each case the mis-match was obscured by closely related areas of delayed xenon wash-out. In those patients where xenon demonstrated greater sensitivity in identifying areas of pulmonary disease, the lesions noted on wash-out appeared as areas of positive activity, while with krypton the defects were always photogenic and, when small probably obscured by scatter from adjacent normal activity. In the patient who might have been improperly categorized as a mis-match without the krypton study, the xenon study may have been normal because of inadequate equilibration time. (author)

Optimization of krypton yields for rp-process studies at ISOLDE (CERN)

CERN Document Server

Kankainen, Anu Kristiina; Fraile-Prieto, L M; Jokinen, A; Leitner, M S; Oinonen, M; Peräjärvi, K; Ravn, H L

2004-01-01

The production of neutron-deficient krypton isotopes having astrophysical importance has been studied at the ISOLDE PBS facility at CERN. To investigate several effects on the yield a Monte Carlo code has been extensively applied.

Fluoride and Oral Health.

Science.gov (United States)

O'Mullane, D M; Baez, R J; Jones, S; Lennon, M A; Petersen, P E; Rugg-Gunn, A J; Whelton, H; Whitford, G M

2016-06-01

The discovery during the first half of the 20th century of the link between natural fluoride, adjusted fluoride levels in drinking water and reduced dental caries prevalence proved to be a stimulus for worldwide on-going research into the role of fluoride in improving oral health. Epidemiological studies of fluoridation programmes have confirmed their safety and their effectiveness in controlling dental caries. Major advances in our knowledge of how fluoride impacts the caries process have led to the development, assessment of effectiveness and promotion of other fluoride vehicles including salt, milk, tablets, toothpaste, gels and varnishes. In 1993, the World Health Organization convened an Expert Committee to provide authoritative information on the role of fluorides in the promotion of oral health throughout the world (WHO TRS 846, 1994). This present publication is a revision of the original 1994 document, again using the expertise of researchers from the extensive fields of knowledge required to successfully implement complex interventions such as the use of fluorides to improve dental and oral health. Financial support for research into the development of these new fluoride strategies has come from many sources including government health departments as well as international and national grant agencies. In addition, the unique role which industry has played in the development, formulation, assessment of effectiveness and promotion of the various fluoride vehicles and strategies is noteworthy. This updated version of 'Fluoride and Oral Health' has adopted an evidence-based approach to its commentary on the different fluoride vehicles and strategies and also to its recommendations. In this regard, full account is taken of the many recent systematic reviews published in peer reviewed literature.

Effects of 960 nm diode laser irradiation on dental enamel in vitro: temperature and morphological analysis and evaluation of enamel demineralization

International Nuclear Information System (INIS)

Kato, Ilka Tiemy

2004-01-01

The aim of this study is to determine the effects of diode laser irradiation on enamel demineralization. To achieve this goal appropriate photon absorbing substances for the laser radiation, safe laser parameters and adequate temperature measuring apparatus had to be determined. Next, the effects of diode laser and acidulated phosphate fluoride on enamel demineralization by calcium content analysis were evaluated with inductively coupled plasma atomic emission spectrometry (ICP-AES). In the first part of the study, five dyes consisting of vegetable coal diluted in five different liquids were analyzed and vegetable coal diluted in physiological solution was chosen for use as absorber. Methodologies to measure pulp chamber temperature were evaluated and modeling clay was chosen as fixture for the enamel samples held at body temperature. In the second part of the study, different energy density parameters (1.8 J/cm 2 , 3.7 J/cm 2 , 5.6 J/cm 2 , 7.4 J/cm 2 and 9.3 J/cm 2 ) exposure times (10, 15, 20, 25 e 30 seconds) and time intervals between dye application and laser irradiation (5, 30, 60, 90 e 120 seconds) were evaluated with respect to temperature changes in the pulp chamber. The enamel morphology was analyzed by scanning electron microscopy. Acid resistance was measured using seventy five enamel specimens, divided in five groups (control, fluoride, laser, laser + fluoride and fluoride + laser). The amount of calcium lost during demineralization in lactic acid was measured by ICP-AES. The results obtained in this experiment permit the conclusion that diode laser irradiation did not increase acid resistance. When associated with fluoride, the acid resistance did not differ from the results obtained with fluoride alone. (author)

Fluoride level in saliva after bonding orthodontic brackets with a fluoride containing adhesive

NARCIS (Netherlands)

Ogaard, B; Arends, J; Helseth, H; Dijkman, G; vanderKuijl, M

The fluoride level in saliva is considered an important parameter in caries prevention. Elevation of the salivary fluoride level by a fluoride-releasing orthodontic bonding adhesive would most likely be beneficial in the prevention of enamel caries. In this study, the fluoride level in saliva was

Electron impact excitation of autoionising states of krypton

Science.gov (United States)

Srivastava, S. K.; Trajmar, S.

1978-01-01

Energy-loss spectra of krypton in the region between 21 and 29 eV have been obtained at electron impact energies of 30, 60 and 100 eV. For each energy, the angular distribution of intensities has been measured at 5, 10 and 15 deg scattering angles. Assignments of spectral features found in this region are suggested and a comparison is made with previous measurements.

Comparative Evaluation of Efficacy of Iontophoresis with 0.33% Sodium Fluoride Gel and Diode Laser Alone on Occlusion of Dentinal Tubules.

Science.gov (United States)

Patil, Anup Raghunath; Varma, Siddhartha; Suragimath, Girish; Abbayya, Keshava; Zope, Sameer Anil; Kale, Vishwajeet

2017-08-01

Dentinal Hypersensitivity (DH) is one of the most commonly encountered clinical problems. Literature reveals no specific therapy to satisfactorily eliminate dentinal hypersensitivity. The aim of this study was to assess and compare the efficacy of iontophoresis with 0.33% Sodium Fluoride (NaF) gel and diode laser alone in dentinal tubule occlusion. This in vitro study included 20 teeth with intact root surfaces unaltered by extraction procedure for specimen preparation. Each tooth was cleaned, air dried and cut into three sections. Total 60 sections were prepared (30 longitudinal and 30 transverse sections), which were acid etched. In control group, no treatment was carried. In iontophoresis treatment group, samples were inserted into a foam tray containing 0.33 % NaF Gel and subjected to 1.5 mA output current for three minutes. In laser treatment group, specimens were lased with 980 nm diode laser at 0.5 W/PW (62.2J /cm 2 ) in a noncontact mode for 30 seconds. Specimens were evaluated under Scanning Electron Microscope (SEM) at 10KV to 20KV under x 2000, x5000 magnification for surface characteristics and patency of dentinal tubules. Total number of tubules visible, open, completely and partially occluded were recorded in each microphotograph and compared. On comparison, laser group showed the least number of open tubules i.e., 130 (31.1%) followed by iontophoresis group, 155 (51.32%) and control group 417 (100%). Diode laser application provided better results as compared to iontophoresis on occlusion of dentinal tubules. Hence, it can be used to treat the patients with DH.

KrCl lasers for fusion. Final report

International Nuclear Information System (INIS)

1984-01-01

The lasing characteristics of the Krypton Chloride excimer have been investigated in an e-beam laser facility. The results of experiments have been compared with the predictions of a comprehensive numerical kinetics model. The model predicts that the formation efficiency for KrCl* should be quite high (approx. = 20%) and these predictions appear to be borne out by experimental gain measurements. However, observed intrinsic laser efficiencies are poor, about 1 percent being the best observed in this program. We conclude that the poor lasing performance results from an adverse gain to loss ratio and an extreme sensitivity to optics losses because of the low characteristics magnitude of the gain

The effect of fractional CO2 laser irradiation on remineralization of enamel white spot lesions.

Science.gov (United States)

Poosti, Maryam; Ahrari, Farzaneh; Moosavi, Horieh; Najjaran, Hoda

2014-07-01

This study investigated the combined effect of fractional CO(2) laser irradiation and fluoride on treatment of enamel caries. Sixty intact premolars were randomly assigned into four groups and then stored in a demineralizing solution to induce white spot lesions. Tooth color was determined at baseline (T1) and after demineralization (T2). Afterwards, the teeth in group 1 remained untreated (control), while group 2 was exposed to an acidulated phosphate fluoride (APF) gel for 4 min. In groups 3 and 4, a fractional CO(2) laser was applied (10 mJ, 200 Hz, 10 s) either before (group 3) or through (group 4) the APF gel. The teeth were then immersed in artificial saliva for 90 days while subjected to daily fluoride mouthrinse and weekly brushing. Color examinations were repeated after topical fluoride application (T3) and 90 days later (T4). Finally, the teeth were sectioned, and microhardness was measured at the enamel surface and at 30 and 60 μ from the surface. In both lased groups, the color change between T1 and T4 stages (∆E(T1-T4)) was significantly lower than those of the other groups (p Laser irradiation followed by fluoride application (group 3) caused a significant increase in surface microhardness compared to APF alone and control groups (p laser before fluoride therapy is suggested for recovering the color and rehardening of demineralized enamel.

Ceramic Laser Materials

Directory of Open Access Journals (Sweden)

Guillermo Villalobos

2012-02-01

Full Text Available Ceramic laser materials have come a long way since the first demonstration of lasing in 1964. Improvements in powder synthesis and ceramic sintering as well as novel ideas have led to notable achievements. These include the first Nd:yttrium aluminum garnet (YAG ceramic laser in 1995, breaking the 1 KW mark in 2002 and then the remarkable demonstration of more than 100 KW output power from a YAG ceramic laser system in 2009. Additional developments have included highly doped microchip lasers, ultrashort pulse lasers, novel materials such as sesquioxides, fluoride ceramic lasers, selenide ceramic lasers in the 2 to 3 μm region, composite ceramic lasers for better thermal management, and single crystal lasers derived from polycrystalline ceramics. This paper highlights some of these notable achievements.

Ceramic Laser Materials

Science.gov (United States)

Sanghera, Jasbinder; Kim, Woohong; Villalobos, Guillermo; Shaw, Brandon; Baker, Colin; Frantz, Jesse; Sadowski, Bryan; Aggarwal, Ishwar

2012-01-01

Ceramic laser materials have come a long way since the first demonstration of lasing in 1964. Improvements in powder synthesis and ceramic sintering as well as novel ideas have led to notable achievements. These include the first Nd:yttrium aluminum garnet (YAG) ceramic laser in 1995, breaking the 1 KW mark in 2002 and then the remarkable demonstration of more than 100 KW output power from a YAG ceramic laser system in 2009. Additional developments have included highly doped microchip lasers, ultrashort pulse lasers, novel materials such as sesquioxides, fluoride ceramic lasers, selenide ceramic lasers in the 2 to 3 μm region, composite ceramic lasers for better thermal management, and single crystal lasers derived from polycrystalline ceramics. This paper highlights some of these notable achievements. PMID:28817044

Simultaneous detection of xenon and krypton in equine plasma by gas chromatography-tandem mass spectrometry for doping control.

Science.gov (United States)

Kwok, Wai Him; Choi, Timmy L S; So, Pui-Kin; Yao, Zhong-Ping; Wan, Terence S M

2017-02-01

Xenon can activate the hypoxia-inducible factors (HIFs). As such, it has been allegedly used in human sports for increasing erythropoiesis. Krypton, another noble gas with reported narcosis effect, can also be expected to be a potential and less expensive erythropoiesis stimulating agent. This has raised concern about the misuse of noble gases as doping agents in equine sports. The aim of the present study is to establish a method for the simultaneous detection of xenon and krypton in equine plasma for the purpose of doping control. Xenon- or krypton-fortified equine plasma samples were prepared according to reported protocols. The target noble gases were simultaneously detected by gas chromatography-triple quadrupole mass spectrometry using headspace injection. Three xenon isotopes at m/z 129, 131, and 132, and four krypton isotopes at m/z 82, 83, 84, and 86 were targeted in selected reaction monitoring mode (with the precursor ions and product ions at identical mass settings), allowing unambiguous identification of the target analytes. Limits of detection for xenon and krypton were about 19 pmol/mL and 98 pmol/mL, respectively. Precision for both analytes was less than 15%. The method has good specificity as background analyte signals were not observed in negative equine plasma samples (n = 73). Loss of analytes under different storage temperatures has also been evaluated. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Fluoride release, recharge and flexural properties of polymethylmethacrylate containing fluoridated glass fillers.

Science.gov (United States)

Al-Bakri, I A; Swain, M V; Naoum, S J; Al-Omari, W M; Martin, E; Ellakwa, A

2014-06-01

The purpose of this study was to investigate the effect of fluoridated glass fillers on fluoride release, recharge and the flexural properties of modified polymethylmethacrylate (PMMA). Specimens of PMMA denture base material with various loading of fluoridated glass fillers (0%, 1%, 2.5%, 5% and 10% by weight) were prepared. Flexural properties were evaluated on rectangular specimens (n = 10) aged in deionized water after 24 hours, 1 and 3 months. Disc specimens (n = 10) were aged for 43 days in deionized water and lactic acid (pH 4.0) and fluoride release was measured at numerous intervals. After ageing, specimens were recharged and fluoride re-release was recorded at 1, 3 and 7 days after recharge. Samples containing 2.5%, 5% and 10% glass fillers showed significantly (p glass fillers specimens. All experimental specimens exhibited fluoride release in both media. The flexural strength of specimens decreased in proportion to the percentage filler inclusion with the modulus of elasticity values remaining within ISO Standard 1567. The modified PMMA with fluoridated glass fillers has the ability to release and re-release fluoride ion. Flexural strength decreased as glass filler uploading increased. © 2014 Australian Dental Association.

Kilo-electron-volt neutron capture cross sections of the krypton isotopes

International Nuclear Information System (INIS)

Walter, G.; Leugers, B.; Kappeler; Bao, Z.Y.; Reffo, G.; Fabbri, F.

1986-01-01

The neutron capture cross sections of the stable krypton isotopes were determined in the energy interval from 4 to 250 keV using a C/sub 6/D/sub 6/-detector system in conjunction with the time-of-flight technique. The energy resolution of the measurement was 4% at 20 keV and 6% at 100 keV, and the experimental uncertainties were typically 6 to 10%. The measurements were complemented by statistical model calculations of all krypton isotopes in the mass range 78 < A < 86 to also obtain reliable cross sections for the unstable nuclei /sup 79,81,85/Kr. These calculations were based on local systematics for all relevant parameters, and the results were estimated to show uncertainties of 20 to 25%. Maxwellian average cross sections were calculated for kT=30 keV

Fluoride glass fiber optics

CERN Document Server

Aggarwal, Ishwar D

1991-01-01

Fluoride Glass Fiber Optics reviews the fundamental aspects of fluoride glasses. This book is divided into nine chapters. Chapter 1 discusses the wide range of fluoride glasses with an emphasis on fluorozirconate-based compositions. The structure of simple fluoride systems, such as BaF2 binary glass is elaborated in Chapter 2. The third chapter covers the intrinsic transparency of fluoride glasses from the UV to the IR, with particular emphasis on the multiphonon edge and electronic edge. The next three chapters are devoted to ultra-low loss optical fibers, reviewing methods for purifying and

A simple and colorimetric fluoride receptor and its fluoride-responsive organogel

Energy Technology Data Exchange (ETDEWEB)

Yu Xudong, E-mail: 081022009@fudan.edu.cn [College of Science, Hebei University of Science and Technology, Yuhua Road 70, Shijiazhuang 050080 (China); Li Yajuan [College of Science, Hebei University of Science and Technology, Yuhua Road 70, Shijiazhuang 050080 (China); Yin Yaobing; Yu Decai [College of Science, Hebei University of Engineering, 199 South street of Guangming, Handan 056038 (China)

2012-08-01

In this paper, a new p-nitrophenylhydrozine-based anion receptor 1 containing cholesterol group had been designed and synthesized. It could selectively recognize fluoride among different anions tested with color changes from pale yellow to red for visual detection. Simultaneously, it could gel in cyclohexane, and the gel was also fluoride-responsive. When treated with TBAF (tetra-n-butylammonium fluoride), the gel could undergo gel-sol transition accompanied by color, morphology and surface changes. The binding mechanism had been investigated by UV-vis and {sup 1}HNMR (proton nuclear magnetic resonance spectra) titrations. From SEM (scanning electron microscope), SAXS (small-angle X-ray scattering), IR (Infrared Spectroscopy) and CA (contact angle) experiments, it was indicated that the addition of F{sup -} could destroy the molecule assembly of host 1 in the gel state, thus resulting in the gel-to-sol transition due to the binding site competition effect. To the best of our knowledge, this was the simplest fluoride-responsive organogel with high selectivity. Highlights: Black-Right-Pointing-Pointer A novel kind receptor for selective recognition of fluoride had been designed. Black-Right-Pointing-Pointer Its organogel was also fluoride-responsive. Black-Right-Pointing-Pointer This is the simplest fluoride-responsive organogel with high selectivity.

Electromagnetic calorimeter on liquid krypton

International Nuclear Information System (INIS)

Bazzotti, M.; Bianco, G.L.; Lanni, F.; Maggi, B.; Palombo, F.; Sala, A.

1990-01-01

This paper reports on use of noble condensed gases as calorimeter media that is attractive due to the possibility to get not only good energy resolution (like in NaI and CsI calorimeters) but better space resolution for photons. Longitudinal segmentation can provide information for particle identification by dE/dx and also e/π-separation based on longitudinal structure of the shower. The best material for this aim is of course liquid Zenon, but it is impossible to get the necessary amount of it in reasonable time. Therefore, the authors have stopped their choice on the next candidate-liquid Krypton (LKr). Its sufficient amount can be obtained before to the beginning of the experiment

Muonium localization in solid krypton

International Nuclear Information System (INIS)

Storchak, V.; Cox, S.F.J.; Brewer, J.H.; Morris, G.D.

1995-06-01

Muonium spin relaxation in zero, longitudinal and transverse magnetic fields has been studied in solid and liquid krypton in the temperature range from 2 K to 120 K. In the solid at low temperatures, the spin dynamics exhibit features characteristic of a magnetically dilute crystal, permitting measurements of exceptionally low muonium diffusion rates. At the lowest temperatures, a static Kubo-Toyabe relaxation function has been observed for the first time for the atomic muonium state, indicating strong interstitial localization in the Kr lattice at low temperatures; muonium is determined to be localized at the tetrahedral interstitial position. At high temperatures, muonium diffusion in solid Kr exhibits a non-classical behaviour. (author). 31 refs., 6 figs

Fluoride metabolism in plants

Energy Technology Data Exchange (ETDEWEB)

Peters, R; Shorthouse, M

1964-04-04

Grass seedlings exposed to inorganic fluoride solutions do not take up appreciable amounts of fluoride until concentrations of more than 1.0 mM (19 p.p.m.) are used. No formation of organic fluoride has been found, even with exposure to 15.75 mM fluoride, indicating that there is no formation of fluoroacetate or similar compounds. 8 references, 2 tables.

Mid-Infrared Fiber Lasers (Les fibres laser infrarouge moyen)

Science.gov (United States)

2010-09-01

Marcel Poulain, Université de Rennes / Le Verre Fluoré, France Fluoride Fiber Sources: Problems and Prospects Prof. Marcel Poulain from Rennes...currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1. REPORT DATE (DD-MM-YYYY) 2. REPORT TYPE 3. DATES...Les fibres laser infrarouge moyen (RTO-MP-SET-171) Synthèse Les sources laser en infrarouge moyen sont nécessaires aux systèmes actifs de

Bottled Water and Fluoride

Science.gov (United States)

... Private Wells Infant Formula Fluorosis Public Health Service Recommendation Water Operators & Engineers Water Fluoridation Additives Shortages of Fluoridation Additives Drinking Water Pipe Systems CDC-Sponsored Water Fluoridation Training Links to Other ...

Effective and accurate approach for modeling of commensurate-incommensurate transition in krypton monolayer on graphite.

Science.gov (United States)

Ustinov, E A

2014-10-07

Commensurate-incommensurate (C-IC) transition of krypton molecular layer on graphite received much attention in recent decades in theoretical and experimental researches. However, there still exists a possibility of generalization of the phenomenon from thermodynamic viewpoint on the basis of accurate molecular simulation. Recently, a new technique was developed for analysis of two-dimensional (2D) phase transitions in systems involving a crystalline phase, which is based on accounting for the effect of temperature and the chemical potential on the lattice constant of the 2D layer using the Gibbs-Duhem equation [E. A. Ustinov, J. Chem. Phys. 140, 074706 (2014)]. The technique has allowed for determination of phase diagrams of 2D argon layers on the uniform surface and in slit pores. This paper extends the developed methodology on systems accounting for the periodic modulation of the substrate potential. The main advantage of the developed approach is that it provides highly accurate evaluation of the chemical potential of crystalline layers, which allows reliable determination of temperature and other parameters of various 2D phase transitions. Applicability of the methodology is demonstrated on the krypton-graphite system. Analysis of phase diagram of the krypton molecular layer, thermodynamic functions of coexisting phases, and a method of prediction of adsorption isotherms is considered accounting for a compression of the graphite due to the krypton-carbon interaction. The temperature and heat of C-IC transition has been reliably determined for the gas-solid and solid-solid system.

Radiometric titration of officinal radiopharmaceuticals using radioactive kryptonates as end-point indicators. II. Citric, tartaric, undecylenic acids

Energy Technology Data Exchange (ETDEWEB)

Harangozo, M.; Jombik, J.; Schiller, P. (Komenskeho Univ., Bratislava (Czechoslovakia). Farmaceuticka Fakulta); Toelgyessy, J. (Slovenska Vysoka Skola Technicka, Bratislava (Czechoslovakia). Chemickotechnologicka Fakulta)

1981-01-01

A method for the determination of citric, tartaric and undecylenic acids based on radiometric titration with 0.1 or 0.05 mole.l/sup -1/ NaOH was developed. As an indicator of the end point, radioactive kryptonate of glass was used. Experimental technique, results of determinations as well as other possible applications of the radioactive kryptonate of glass for end point determination in alkalimetric analyses of officinal pharmaceuticals are discussed.

Effects of fluoride and epigallocatechin gallate on soft-drink-induced dental erosion of enamel and root dentin

Directory of Open Access Journals (Sweden)

Yin-Lin Wang

2018-04-01

Full Text Available Background/Purpose: Fluoride and epigallocatechin gallate (EGCG have been proven to prevent dental caries. The purpose of this study was to evaluate the effects of fluoride and EGCG on soft-drink-induced dental erosion in vitro. Methods: Forty enamel and dentin specimens were prepared from extracted human teeth. The specimens were divided into 4 groups and treated separately with distilled water (as control, 0.5 M sodium fluoride (NF, 400 μM EGCG (EG, and a solution containing 0.5 M NaF and 400 μM EGCG (FG. Cyclic erosive treatment was performed according to the experimental procedures. The specimens were analyzed using laser scanning confocal microscopy, scanning electron microscopy, and a microhardness tester. The data were analyzed using ANOVA and Bonferroni's post hoc test. The significance level was set at 5%. Results: The amount of substance loss was lower in the NF and EG groups than in the control group (p < 0.05. The erosion-caused substance loss was more pronounced in the dentin than in the enamel specimens. Surface microhardness loss was lower in the NF and EG groups than in the control group (p < 0.05. The diameter of the dentinal tubule was wider in the control group than in the NF and EG groups (p < 0.05. No combined effects were observed in the FG group. Conclusion: Both fluoride and EGCG are effective in preventing soft-drink-induced erosion compared with the control group. Fluoride and EGCG may interfere with each other. The mechanisms of the anti-erosive effect need to be explored in the future. Keywords: Dental erosion, Fluoride, Epigallocatechin gallate, Soft drinks, Laser scanning confocal microscopy

Quantitative pump-induced wavefront distortions in laser-diode- and flash-lamp-pumped Nd:YLF laser rods

International Nuclear Information System (INIS)

Skeldon, M.D.; Saager, R.B.; Seka, W.

1999-01-01

Detailed interferometric measurements of the induced thermal distortions due to laser-diode and xenon flashlamp pumping of Nd:YLF are presented. The thermal distortions are quantified in terms of the primary aberrations of defocus, astigmatism, coma, and spherical. Defocus and astigmatism are shown to dominate the thermal aberrations. The measured defocus and astigmatism are converted to the conventional thermal-focal lengths in two perpendicular directions with respect to the Nd:YLF crystalline c axis for each of the two polarization states σ and π. A comparison of the thermal-focal lengths measured with the xenon flashlamp- and laser-diode-pumped rods is given when the rods are pumped to the same small-signal gain. The authors calculate effective dioptric-power coefficients from the data for comparison to those reported in the literature for krypton-flashlamp pumping. A thermal-time constant of 1.5 s is measured for the laser-diode-pumped Nd:YLF laser rod

Monitoring of air pollutants and greenhouse gases. Monitoring Krypton-85

International Nuclear Information System (INIS)

Novitchkov, V.

1996-01-01

Krypton-85 is an anthropogenic radioactive noble gas, a gaseous fission product which builds up in the atmosphere. The World Meteorological Organization (WMO) Global Atmospheric Watch (GAW) integrates many monitoring and research activities involving the measurements of atmospheric composition. Kr-85 represents one of the gases recommended by the WMO for monitoring. The collaborative program of the Moscow State Engineering Physics Institute (MEPI) and the US Air Resources Laboratory (ARL) NOAA activities is aimed at determining the possible future consequences of Krypton-85 content (trend) increasing in the earth's atmosphere. The research is conducted at the MEPI to study the character of KR-85 release into the atmosphere and its distribution in the atmosphere, to determine Kr-85 possible sources. If only the question of the direct impact of Kr-85 on climate would be considered, only the order of magnitude of the atmospheric concentration would be of interest. In this case almost any available detection method and a precision as low as some 10% would be acceptable. If however, Kr-85 is to be applied as a tracer for the improvement of our present knowledge of local, regional and global transport and mixing processes and the validation of global-scale transport and mixing models, a much higher precision is required (order of +1%). This high standard cannot be met without a permanent quality assurance programmer. It is within the framework of the WMO that MEPI and the Air Resources Laboratory NOAA USA proposes collaboration of Kr-85 scientific findings. The project MEPI open-quotes Monitoring Krypton-85close quotes is being financed through the International Science and Technology Center

Steady state operation of the first cryogenic column in a krypton separation system

International Nuclear Information System (INIS)

von Ammon, R.; Bumiller, W.; Hutter, E.; Neffe, G.

1981-01-01

Recent results obtained during the operation of the inactive test unit KRETA for the cryogenic separation of krypton from simulated reprocessing off-gases are presented. The first rectification column of this unit was modified by shortening its lower part from 18 to 8 practical plates and placing the feed point into the warmer, krypton-rich section. Two essential results were thus achieved: plugging by desubliming xenon was not observed even at xenon feed concentrations as high as 1 vol.-%; and, accumulation of oxygen was much lower than in the column version used previously, thus reducing the potential hazard by ozone formation drastically. The accumulation of methane, however, was found to be high, in agreement with calculations

Fluoride release and recharge abilities of contemporary fluoride-containing restorative materials and dental adhesives.

Science.gov (United States)

Dionysopoulos, Dimitrios; Koliniotou-Koumpia, Eugenia; Helvatzoglou-Antoniades, Maria; Kotsanos, Nikolaos

2013-01-01

The aim of this study was to evaluate the fluoride release of five fluoride-releasing restorative materials and three dental adhesives, before and after NaF solution treatment. Five restorative materials (Fuji IX GP, GC Corp.; Ketac N100, 3M ESPE; Dyract Extra, Dentsply; Beautifil II, Shofu Inc.; Wave, SDI) and three dental adhesives (Stae, SDI; Fluorobond II - Shofu Inc.; Prime & Bond NT, Dentsply) were investigated before and after NaF solution treatment. A fluoride ion-selective electrode was to measure fluoride concentrations. During the 86-day period before NaF solution treatment, Fuji IX GP released the highest amount of fluoride among the restorative materials while Prime & Bond NT was the highest among the dental adhesives. After NaF solution treatment, Fuji IX GP again ranked the highest in fluoride release among the restorative materials while Fluorobond II ranked the highest among dental adhesives. It was concluded that the compositions and setting mechanisms of fluoride-containing dental materials influenced their fluoride release and recharge abilities.

Effects of 960 nm diode laser irradiation on dental enamel in vitro: temperature and morphological analysis and evaluation of enamel demineralization; Estudo in vitro dos efeitos promovidos pelo laser de diodo em 960 nm no esmalte dental humano: analise de temperatura, analise morfologica e avaliacao da resistencia a desmineralizacao

Energy Technology Data Exchange (ETDEWEB)

Kato, Ilka Tiemy

2004-07-01

The aim of this study is to determine the effects of diode laser irradiation on enamel demineralization. To achieve this goal appropriate photon absorbing substances for the laser radiation, safe laser parameters and adequate temperature measuring apparatus had to be determined. Next, the effects of diode laser and acidulated phosphate fluoride on enamel demineralization by calcium content analysis were evaluated with inductively coupled plasma atomic emission spectrometry (ICP-AES). In the first part of the study, five dyes consisting of vegetable coal diluted in five different liquids were analyzed and vegetable coal diluted in physiological solution was chosen for use as absorber. Methodologies to measure pulp chamber temperature were evaluated and modeling clay was chosen as fixture for the enamel samples held at body temperature. In the second part of the study, different energy density parameters (1.8 J/cm{sup 2}, 3.7 J/cm{sup 2}, 5.6 J/cm{sup 2}, 7.4 J/cm{sup 2} and 9.3 J/cm{sup 2}) exposure times (10, 15, 20, 25 e 30 seconds) and time intervals between dye application and laser irradiation (5, 30, 60, 90 e 120 seconds) were evaluated with respect to temperature changes in the pulp chamber. The enamel morphology was analyzed by scanning electron microscopy. Acid resistance was measured using seventy five enamel specimens, divided in five groups (control, fluoride, laser, laser + fluoride and fluoride + laser). The amount of calcium lost during demineralization in lactic acid was measured by ICP-AES. The results obtained in this experiment permit the conclusion that diode laser irradiation did not increase acid resistance. When associated with fluoride, the acid resistance did not differ from the results obtained with fluoride alone. (author)

No calcium-fluoride-like deposits detected in plaque shortly after a sodium fluoride mouthrinse.

Science.gov (United States)

Vogel, G L; Tenuta, L M A; Schumacher, G E; Chow, L C

2010-01-01

Plaque 'calcium-fluoride-like' (CaF(2)-like) and fluoride deposits held by biological/bacterial calcium fluoride (Ca-F) bonds appear to be the source of cariostatic concentrations of fluoride in plaque fluid. The aim of this study was to quantify the amounts of plaque fluoride held in these reservoirs after a sodium fluoride rinse. 30 and 60 min after a 228 microg/g fluoride rinse, plaque samples were collected from 11 volunteers. Each sample was homogenized, split into 2 aliquots (aliquots 1 and 2), centrifuged, and the recovered plaque fluid combined and analyzed using microelectrodes. The plaque mass from aliquot 1 was retained. The plaque mass from aliquot 2 was extracted several times with a solution having the same fluoride, calcium and pH as the plaque fluid in order to extract the plaque CaF(2)-like deposits. The total fluoride in both aliquots was then determined. In a second experiment, the extraction completeness was examined by applying the above procedure to in vitro precipitates containing known amounts of CaF(2)-like deposits. Nearly identical fluoride concentrations were found in both plaque aliquots. The extraction of the CaF(2)-like precipitates formed in vitro removed more than 80% of these deposits. The results suggest that either CaF(2)-like deposits were not formed in plaque or, if these deposits had been formed, they were rapidly lost. The inability to form persistent amounts of CaF(2)-like deposits in plaque may account for the relatively rapid loss of plaque fluid fluoride after the use of conventional fluoride dentifrices or rinses. (c) 2010 S. Karger AG, Basel.

Calcium fluoride whispering gallery mode optical resonator with reduced thermal sensitivity

Science.gov (United States)

Savchenkov, Anatoliy; Matsko, Andrey

2018-03-01

We demonstrate a crystalline CaF2 resonator with thermal sensitivity of the optical modes approaching zero. The resonator is made by laminating a calcium fluoride layer forming an optical monolithic cavity with ceramic compensation layers. The ceramics is characterized with negative thermal expansion coefficient achievable in a certain temperature range. The thermally compensated resonator has a potential application for laser frequency stabilization.

Recovery of krypton-85 from dissolver off-gas streams

International Nuclear Information System (INIS)

Law, J.P.; Lamb, K.M.

1988-01-01

The Rare Gas Plant at the Idaho Chemical Processing Plant Recovers fission product krypton and xenon from dissolver off gas streams. Recently the system was upgraded to allow processing of hydrogen rich dissolver off-gas streams. A trickle bed hydrogen recombiner was installed and tested. The Rare Gas Plant can now safely process gas streams containing up to 80% hydrogen

Fluoride concentration in urine after silver diamine fluoride application on tooth enamel

Science.gov (United States)

Sari, D. L.; Bahar, A.; Gunawan, H. A.; Adiatman, M.; Rahardjo, A.; Maharani, D. A.; Toptanci, I. R.; Yavuz, I.

2017-08-01

Silver Diammine Fluoride (SDF), which contains fluoride, is known to inhibit tooth enamel demineralization and increase fluoride concentrations in saliva and urine. The aim of this study is to analyze the fluoride concentration in urine after application of SDF on tooth enamel. Urine from four subjects was collected prior to, 30 minutes after, and two and three hours after the application of SDF, and an ion-selective electrode was used to measure the fluoride concentrations. There was no significant difference between time 1 and time 2, time 1 and time 3, time 1 and time 4, time 2 and 3 (p > 0.05), and there was a significant difference between time 2 and time 4 as well as time 3 and time 4 (p < 0.05). There was a decrease in the concentration of fluoride ions in urine from the baseline to 30 minutes after application, and an increase from baseline to two and three hours after the application of SDF.

Cerium fluoride nanoparticles protect cells against oxidative stress

International Nuclear Information System (INIS)

Shcherbakov, Alexander B.; Zholobak, Nadezhda M.; Baranchikov, Alexander E.; Ryabova, Anastasia V.; Ivanov, Vladimir K.

2015-01-01

A novel facile method of non-doped and fluorescent terbium-doped cerium fluoride stable aqueous sols synthesis is proposed. Intense green luminescence of CeF 3 :Tb nanoparticles can be used to visualize these nanoparticles' accumulation in cells using confocal laser scanning microscopy. Cerium fluoride nanoparticles are shown for the first time to protect both organic molecules and living cells from the oxidative action of hydrogen peroxide. Both non-doped and terbium-doped CeF 3 nanoparticles are shown to provide noteworthy protection to cells against the vesicular stomatitis virus. - Highlights: • Facile method of CeF 3 and CeF 3 :Tb stable aqueous sols synthesis is proposed. • Naked CeF 3 nanoparticles are shown to be non-toxic and to protect cells from the action of H 2 O 2 . • CeF 3 and CeF 3 :Tb nanoparticles are shown to protect living cells against the vesicular stomatitis virus

Cerium fluoride nanoparticles protect cells against oxidative stress

Energy Technology Data Exchange (ETDEWEB)

Shcherbakov, Alexander B.; Zholobak, Nadezhda M. [Zabolotny Institute of Microbiology and Virology, National Academy of Sciences of Ukraine, Kyiv D0368 (Ukraine); Baranchikov, Alexander E. [Kurnakov Institute of General and Inorganic Chemistry of the Russian Academy of Sciences, Moscow 119991 (Russian Federation); Ryabova, Anastasia V. [Prokhorov General Physics Institute of the Russian Academy of Sciences, Moscow 119991 (Russian Federation); National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Moscow 115409 (Russian Federation); Ivanov, Vladimir K., E-mail: van@igic.ras.ru [Kurnakov Institute of General and Inorganic Chemistry of the Russian Academy of Sciences, Moscow 119991 (Russian Federation); National Research Tomsk State University, Tomsk 634050 (Russian Federation)

2015-05-01

A novel facile method of non-doped and fluorescent terbium-doped cerium fluoride stable aqueous sols synthesis is proposed. Intense green luminescence of CeF{sub 3}:Tb nanoparticles can be used to visualize these nanoparticles' accumulation in cells using confocal laser scanning microscopy. Cerium fluoride nanoparticles are shown for the first time to protect both organic molecules and living cells from the oxidative action of hydrogen peroxide. Both non-doped and terbium-doped CeF{sub 3} nanoparticles are shown to provide noteworthy protection to cells against the vesicular stomatitis virus. - Highlights: • Facile method of CeF{sub 3} and CeF{sub 3}:Tb stable aqueous sols synthesis is proposed. • Naked CeF{sub 3} nanoparticles are shown to be non-toxic and to protect cells from the action of H{sub 2}O{sub 2}. • CeF{sub 3} and CeF{sub 3}:Tb nanoparticles are shown to protect living cells against the vesicular stomatitis virus.

Study of emission of a volume nanosecond discharge plasma in xenon, krypton and argon at high pressures

International Nuclear Information System (INIS)

Baksht, E Kh; Lomaev, Mikhail I; Rybka, D V; Tarasenko, Viktor F

2006-01-01

The emission properties of a volume nanosecond discharge plasma produced in xenon, krypton and argon at high pressures in a discharge gap with a cathode having a small radius of curvature are studied. Spectra in the range 120-850 nm and amplitude-time characteristics of xenon emission at different regimes and excitation techniques are recorded and analysed. It is shown that upon excitation of the volume discharge initiated by a beam of avalanche electrons, at least 90% of the energy in the spectral range 120-850 nm is emitted by xenon dimers. For xenon at a pressure of 1.2 atm, ∼45 mJ of the spontaneous emission energy was obtained in the full solid angle in a pulse with the full width at half-maximum ∼130 ns. (laser applications and other topics in quantum electronics)

Removing krypton from xenon by cryogenic distillation to the ppq level

Science.gov (United States)

Aprile, E.; Aalbers, J.; Agostini, F.; Alfonsi, M.; Amaro, F. D.; Anthony, M.; Arneodo, F.; Barrow, P.; Baudis, L.; Bauermeister, B.; Benabderrahmane, M. L.; Berger, T.; Breur, P. A.; Brown, A.; Brown, E.; Bruenner, S.; Bruno, G.; Budnik, R.; Bütikofer, L.; Calvén, J.; Cardoso, J. M. R.; Cervantes, M.; Cichon, D.; Coderre, D.; Colijn, A. P.; Conrad, J.; Cussonneau, J. P.; Decowski, M. P.; de Perio, P.; Di Gangi, P.; Di Giovanni, A.; Diglio, S.; Duchovni, E.; Eurin, G.; Fei, J.; Ferella, A. D.; Fieguth, A.; Franco, D.; Fulgione, W.; Gallo Rosso, A.; Galloway, M.; Gao, F.; Garbini, M.; Geis, C.; Goetzke, L. W.; Grandi, L.; Greene, Z.; Grignon, C.; Hasterok, C.; Hogenbirk, E.; Huhmann, C.; Itay, R.; Kaminsky, B.; Kessler, G.; Kish, A.; Landsman, H.; Lang, R. F.; Lellouch, D.; Levinson, L.; Calloch, M. Le; Lin, Q.; Lindemann, S.; Lindner, M.; Lopes, J. A. M.; Manfredini, A.; Maris, I.; Undagoitia, T. Marrodán; Masbou, J.; Massoli, F. V.; Masson, D.; Mayani, D.; Meng, Y.; Messina, M.; Micheneau, K.; Miguez, B.; Molinario, A.; Murra, M.; Naganoma, J.; Ni, K.; Oberlack, U.; Orrigo, S. E. A.; Pakarha, P.; Pelssers, B.; Persiani, R.; Piastra, F.; Pienaar, J.; Piro, M.-C.; Pizzella, V.; Plante, G.; Priel, N.; Rauch, L.; Reichard, S.; Reuter, C.; Rizzo, A.; Rosendahl, S.; Rupp, N.; Saldanha, R.; Santos, J. M. F. dos; Sartorelli, G.; Scheibelhut, M.; Schindler, S.; Schreiner, J.; Schumann, M.; Lavina, L. Scotto; Selvi, M.; Shagin, P.; Shockley, E.; Silva, M.; Simgen, H.; Sivers, M. v.; Stein, A.; Thers, D.; Tiseni, A.; Trinchero, G.; Tunnell, C.; Upole, N.; Wang, H.; Wei, Y.; Weinheimer, C.; Wulf, J.; Ye, J.; Zhang, Y.; Cristescu, I.

2017-05-01

The XENON1T experiment aims for the direct detection of dark matter in a detector filled with 3.3 tons of liquid xenon. In order to achieve the desired sensitivity, the background induced by radioactive decays inside the detector has to be sufficiently low. One major contributor is the β -emitter ^{85}Kr which is present in the xenon. For XENON1T a concentration of natural krypton in xenon ^{nat}Kr/Xe McCabe-Thiele approach is described. The system demonstrated a krypton reduction factor of 6.4\\cdot 10^5 with thermodynamic stability at process speeds above 3 kg/h. The resulting concentration of ^{nat}Kr/Xe<26 ppq is the lowest ever achieved, almost one order of magnitude below the requirements for XENON1T and even sufficient for future dark matter experiments using liquid xenon, such as XENONnT and DARWIN.

Water Fluoridation Statistics - Percent of PWS population receiving fluoridated water

Data.gov (United States)

U.S. Department of Health & Human Services — 2000-2014. Water Fluoridation Statistics is a biennial report of the percentage and number of people receiving fluoridated water from 2000 through 2014, originally...

Water Fluoridation Statistics - Percent of PWS population receiving fluoridated water

Data.gov (United States)

U.S. Department of Health & Human Services — 2000-2014 Water Fluoridation Statistics is a biennial report of the percentage and number of people receiving fluoridated water from 2000 through 2014, originally...

Evaluation of diode laser and stannous fluoride in the treatment of root sensitivity after access flap surgery: Randomized controlled clinical trial

Directory of Open Access Journals (Sweden)

Chetan Purushottam Raut

2018-01-01

Full Text Available Background: Postsurgical root sensitivity has always been an enigma to the periodontists. There is a plethora of evidence suggesting the presence of root sensitivity following periodontal flap surgical procedures. Thus, the aim of the present study was to compare and evaluate the effect of low-power diode lasers with and without topical application of stannous fluoride (SnF2 gel in the treatment of root sensitivity and also evaluate whether laser creates any placebo effect in the control group or not. Materials and Methods: Thirty patients participated in this study and 99 teeth were included. Root sensitivity was assessed for all groups with a Verbal Rating Scale (VRS. For each patient, the teeth were randomized into three groups. In the test Group I, sensitive teeth were treated with SnF2and diode laser. In the test Group II, sensitive teeth were irradiated with laser only. In the control group, no treatment was performed. Results: The mean ± standard deviation (SD score for VRS and Visual Analog Scale at baseline was not statistically significant (P > 0.05 between the three groups. After 15 min, statistical significant difference was seen in test Group I and test Group II, although no difference was found in the control group. At 15th day and 30th day, the mean ± SD scores were statistically significant (P < 0.05. Conclusion: Within the limitations of the study, it can be concluded that diode lasers alone and in combination with 0.4% SnF2was effective in the treatment of root sensitivity after access flap surgery.

Fluoride releasing and enamel demineralization around orthodontic brackets by fluoride-releasing composite containing nanoparticles.

Science.gov (United States)

Melo, Mary A S; Morais, Weslanny A; Passos, Vanara F; Lima, Juliana P M; Rodrigues, Lidiany K A

2014-05-01

Fluoride-containing materials have been suggested to control enamel demineralization around orthodontic brackets during the treatment with fixed appliances. The improvement of their properties has been made through innovations, such as the application of nanotechnology by incorporation of nanofillers. This in vitro study evaluated the capacity of fluoride releasing and enamel demineralization inhibition of fluoride-releasing nanofilled cement around orthodontic brackets using an artificial caries biofilm model. Forty bovine enamel discs were selected by evaluating surface microhardness and randomized into four groups (n = 10): non-fluoride-releasing microfilled composite, fluoride-releasing microfilled composite, resin-modified glass ionomer cement (RMGI), and fluoride-releasing nanofilled composite (FN). After brackets bonding in each disc, the specimens were subjected to a cariogenic challenge through a Streptococcus mutans biofilm model. After the experimental period, the biofilm formed around the brackets was collected for fluoride analysis and the mineral loss around the brackets was determined by integrated demineralization via cross-sectional microhardness measurement at 20 and 70 μm from the bracket margin. Additionally, samples of each group were subjected to energy-dispersive X-ray spectroscopy (EDX) analysis examined under a scanning electron microscopy (SEM). ANOVA followed by Tukey test were applied for fluoride concentration and mineral loss data, respectively. At both distances, only RMGI statistically differed from the other groups presenting the lowest demineralization, although there was a trend to a lower demineralization of enamel around brackets in FN group. Similar condition was found to fluoride concentration and EDX/SEM analysis. Under the cariogenic exposure condition of this study, the fluoride-releasing nanofilled material had similar performance to fluoride-releasing microfilled materials. The presence of nanofillers in the fluoride

Focusing effects of a laser beam in the non resonant MPI of gases

International Nuclear Information System (INIS)

Baravian, G.; Sultan, G.

1984-09-01

The authors give a method to interpret correctly the multiphoton ionization in the case of no resonance and saturation. The calculation model is applied to hydrogen to calculate the ion production related to the intensity of laser pulse. Different applications and methods are given. The six-photon ionization cross-section of the krypton is calculated [fr

Laser entertainment and light shows in education

Science.gov (United States)

Sabaratnam, Andrew T.; Symons, Charles

2002-05-01

Laser shows and beam effects have been a source of entertainment since its first public performance May 9, 1969, at Mills College in Oakland, California. Since 1997, the Photonics Center, NgeeAnn Polytechnic, Singapore, has been using laser shows as a teaching tool. Students are able to exhibit their creative skills and learn at the same time how lasers are used in the entertainment industry. Students will acquire a number of skills including handling three- phase power supply, operation of cooling system, and laser alignment. Students also acquire an appreciation of the arts, learning about shapes and contours as they develop graphics for the shows. After holography, laser show animation provides a combination of the arts and technology. This paper aims to briefly describe how a krypton-argon laser, galvanometer scanners, a polychromatic acousto-optic modulator and related electronics are put together to develop a laser projector. The paper also describes how students are trained to make their own laser animation and beam effects with music, and at the same time have an appreciation of the operation of a Class IV laser and the handling of optical components.

Design and construction of a cryogenic distillation device for removal of krypton for liquid xenon dark matter detectors.

Science.gov (United States)

Wang, Zhou; Bao, Lei; Hao, Xihuan; Ju, Yonglin

2014-01-01

Liquid xenon (Xe) is one of the commendable detecting media for the dark matter detections. However, the small content of radioactive krypton-85 ((85)Kr) always exists in the commercial xenon products. An efficient cryogenic distillation system to remove this krypton (Kr) from commercial xenon products has been specifically designed, developed, and constructed in order to meet the requirements of the dark matter experiments with high- sensitivity and low-background. The content of krypton in regular commercial xenon products can be reduced from 10(-9) to 10(-12), with 99% xenon collection efficiency at maximum flow rate of 5 kg/h (15SLPM). The purified xenon gases produced by this distillation system can be used as the detecting media in the project of Panda X, which is the first dark matter detector developed in China.

Particle simulation of grid system for krypton ion thrusters

Directory of Open Access Journals (Sweden)

Maolin CHEN

2018-04-01

Full Text Available The transport processes of plasmas in grid systems of krypton (Kr ion thrusters at different acceleration voltages were simulated with a 3D-PIC model, and the result was compared with xenon (Xe ion thrusters. The variation of the screen grid transparency, the accelerator grid current ratio and the divergence loss were explored. It is found that the screen grid transparency increases with the acceleration voltage and decreases with the beam current, while the accelerator grid current ratio and divergence loss decrease first and then increase with the beam current. This result is the same with Xe ion thrusters. Simulation results also show that Kr ion thrusters have more advantages than Xe ion thrusters, such as higher screen grid transparency, smaller accelerator grid current ratio, larger cut-off current threshold, and better divergence loss characteristic. These advantages mean that Kr ion thrusters have the ability of operating in a wide range of current. Through comprehensive analyses, it can be concluded that using Kr as propellant is very suitable for a multi-mode ion thruster design. Keywords: Grid system, Ion thrusters, Krypton, Particle in cell method, Plasma

Oral fluoride levels 1 h after use of a sodium fluoride rinse: effect of sodium lauryl sulfate.

Science.gov (United States)

Vogel, Gerald L; Schumacher, Gary E; Chow, Laurence C; Tenuta, Livia M A

2015-01-01

Increasing the concentration of free fluoride in oral fluids is an important goal in the use of topical fluoride agents. Although sodium lauryl sulfate (SLS) is a common dentifrice ingredient, the influence of this ion on plaque fluid and salivary fluid fluoride has not been examined. The purpose of this study was to investigate the effect of SLS on these parameters and to examine the effect of this ion on total (or whole) plaque fluoride, an important source of plaque fluid fluoride after a sufficient interval following fluoride administration, and on total salivary fluoride, a parameter often used as a surrogate measure of salivary fluid fluoride. Ten subjects accumulated plaque for 48 h before rinsing with a 12 mmol/l NaF (228 µg/g F) rinse containing or not containing 0.5% (w/w) SLS. SLS had no statistically significant effect on total plaque and total saliva fluoride but significantly increased salivary fluid and plaque fluid fluoride (by 147 and 205%, respectively). These results suggest that the nonfluoride components of topical agents can be manipulated to improve the fluoride release characteristics from oral fluoride reservoirs and that statistically significant change may be observed in plaque fluid and salivary fluid fluoride concentrations that may not be observed in total plaque and total saliva fluoride concentrations.

The cariostatic mechanisms of fluoride

OpenAIRE

Kata Rošin-Grget; Kristina Peroš; Ivana Šutej; Krešimir Bašić

2013-01-01

This article discusses the possible cariostatic mechanisms of the action of fluoride. In the past, fluoride inhibition of caries was ascribed to reduced solubility of enamel due to incorporation of fluoride (F–) into the enamel minerals. The present evidence from clinical and laboratory studies suggests that the caries-preventive mode of action of fluoride is mainly topical. There is convincing evidence that fluoride has a major effect on demineralisation and remineralisation of dental hard t...

Heparanase-1 activities in the development of laser induced choroidal neovascularization

Directory of Open Access Journals (Sweden)