Recent Experiments Leading to the Characterization of the Performance of Portable (He-Ne)/CH4 Lasers: Part II: Results of the 1986 LPTF Absolute Frequency Measurements

Science.gov (United States)

Clairon, A.; Dahmani, B.; Acef, O.; Granveaud, M.; Domnin, Yu S.; Pouchkine, S. B.; Tatarenkov, V. M.; Felder, R.

1988-01-01

Comparison of the VNIIFTRI and LPTF frequency multiplication chains has been carried out through the measurement of the frequency of a portable VNIIFTRI (He-Ne)/CH4 laser. Agreement is within 100 Hz (1.1 parts in 1012) and is secured by the very good medium-term frequency repeatability of the (He-Ne)/CH4 VNIIFTRI portable laser (a few parts in 1013). On the same occasion a measurement of the frequency of the BIPM (He-Ne)/CH4 reference laser (B.3) has been performed at LPTF. Other experiments carried out on the BIPM laser show that the reproducibility of the (He-Ne)/CH4 system could be improved by a systematic study and then by a better control of the various perturbing factors which influence the shape of the methane-saturated absorption peak.

Study on the Therapeutic Effect of Dispersive He-Ne Laser on Radiation Proctitis%弥散型He-Ne激光治疗放射性直肠炎的临床研究

Institute of Scientific and Technical Information of China (English)

吴先哲; 宋奇; 邢国良

2012-01-01

目的 探讨弥散型He-Ne激光直肠内照射对放射性直肠炎的临床治疗作用.方法 将功率为30 mW、能量密度为3.62 J/cm2弥散型He-Ne激光导入直肠,使He-Ne激光直接照射直肠病变黏膜,观察患者直肠出血、直肠疼痛、腹泻等,比较治疗前后患者直肠黏膜病理组织学的改变.结果 He-Ne激光可以显著减少放射性直肠炎患者的直肠出血,对直肠疼痛、腹泻等症状的影响不大,能明显减轻黏膜组织的炎症反应,并能促进黏膜的修复.结论 弥散性He-Ne激光直肠腔内照射对放射性直肠炎所致的直肠出血有较好的治疗作用.%Objective To study the therapeutic effect of dispersive He-Ne laser on radiation proctitis. Methods Sent He-Ne laser to the rectum, irradiated the mucoga lesions of the rectum with He-Ne laser, observed the major therapeutic effects of He-Ne laser, including but not limited to rectal bleeding and pain, and diarrhea, and compared the histopathological changes of the rectum mncosa before and after the treatment. Results For radiation proctitis patients, He-Ne laser can significantly reduce significantly rectal bleeding .reduce the and inflammatory reaction of mucosal tissue inflammatory reaction, and as well as can facilitate mucosal tissue repair, but has little effect in relieving other symptoms, such as pain and diarrhea. Conclusions The laser irradiation in the rectal cavity with dispersive He-Ne is effective in treating the bleeding caused by radiation proctitis.

Markers Of Apoptosis In HEP-2 Cells In Vitro Damaged By PHOTOFRIN And He:Ne Laser

International Nuclear Information System (INIS)

KORRAA, S.; ELMAGHRABY, T.K.; HELMY, H.M.

2009-01-01

Photodynamic therapy (PDT), which is a treatment for cancer and certain non-cancerous conditions, requires exposure of cells or tissue to a photosensitizing drug followed by irradiation with visible light of the appropriate wavelength. Although PDT can produce apoptosis or necrosis or a combination of the two mechanisms, PDT is a highly efficient if it induces apoptosis. The aim of the present study is to investigate the effect of combination between photofrin and He:Ne laser on killing Hep-2 cells in vitro, 2 and 24 hours post-laser irradiation. Also, to determine the markers of apoptosis in terms of levels of Bcl-2 protein and Bax mRNA relative expression in PDT treated cells six hours post laser irradiation. Cells viability was measured by trypan blue exclusion test (by light microscope). The results showed that photofrin in combination with He:Ne laser was efficient in decreasing the number of viable cells. It caused 81.47± 2.0 % cell death 2 hours post laser irradiation then reached 52.37± 2.24 % 24 hours post laser irradiation. PDT induced an increase in Bax mRNA relative expression and a decrease in Bcl-2 protein as measured 6 hours post laser irradiation.

Effect of HeNe laser on calcium signals in sperm cells

Science.gov (United States)

Lubart, Rachel; Friedmann, Harry; Cohen, Natalie; Brietbart, Haim

1998-12-01

Irradiation of mouse spermatozoa by 630 nm HeNe laser was found to enhance calcium transport in these cells. The change in Ca transport was investigated through two approaches, the first employing the fluorescent Ca indicator, Fluo-3 AM and a fluorescence microscopic system, and the second the radiolabeled Ca uptake. In both approaches the effect of light on Ca transport was abrogated in the absence of Ca during the irradiation time, indicating that the effect of light is Ca-dependent. The stimulatory effect of light on Ca uptake was inhibited by treatment with catalase, suggesting H2O2 to be involved in light stimulated Ca2+ uptake. The stimulatory effect of light on Ca uptake was abolished in the presence of a voltage-dependent Ca-channel inhibitor, nifedipine, indicating the involvement of a plasma membrane, voltage- dependent Ca-channel. In contrast, addition of nifedipine prior to the HeNe laser irradiation did not affect the light-induced rise in intracellular Ca levels, as measured with Fluo-3 loaded sperm cells. Therefore, it can be concluded that this Ca influx occurs via a voltage- insensitive Ca-channel. The stimulatory effect of light on Ca uptake was almost completely abolished by the mitochondrial uncoupler FCCP. These data imply that light affects the mitochondrial Ca transport mechanisms. It is well known that Ca influx from an extracellular environment is an essential component of a signaling cascade leading to fertilization.

Investigation of the Effect of He-Ne Laser on the Optical Properties through Etched CN-85 and CR-39 Containing Alpha Tracks

International Nuclear Information System (INIS)

Zaki, M.F.; Hegazy, T.M.; Taha, D.H.

2013-01-01

The effects of He-Ne laser on the optical characteristics of Cellulose nitrate, CN-85, and Poly allyl diglycole carbonate, CR-39, nuclear track detectors have been studied by using photoluminescence (PL) and UV-visible spectroscopic techniques. The polymers irradiated with alpha particles with close contact to 241 Am and then exposed to He-Ne laser with different doses. The laser energy intensities ranged between 0 and 217 J/cm 2 . The change in the PL spectra may be explained by chain conformational disorders as well as chain scission. From the UV-visible spectra, it is found that a shift in the absorption edge towards a longer wavelength with increasing laser doses can be readily observed. The absorption peak with increasing dose is seen to change into a broad one. The optical band gaps determined from the UV-visible spectra were found to decrease with the increase of energy intensities of He-Ne laser. These results have been explained on the basis of scission of the polymers due to laser irradiation. The UV absorption tail formation in both polymers was related to the diminution of optical band gap. Results show good correlation with the applied doses.

Measurement of the electron density of a plasma by interferometry with a He - Ne laser ({lambda} = 3.39 {mu}); Mesure de la densite electronique d'un plasma par interferometrie avec un laser He - Ne ({lambda} = 3.39 {mu})

Energy Technology Data Exchange (ETDEWEB)

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

1968-07-01

The characteristics of the He-Ne gas laser used in a simple interferometric technique have been studied. After passing through the plasma, the beam is reflected back into the laser cavity, and the intensity of the laser itself, modulated by this optical feedback, is used to observe the fringes. Furthermore, owing to the coupling of the two laser transitions 0.63{mu} (red) and 3.39{mu} (infra red), interferences in the infra red can be detected by a simple photomultiplier monitoring the red line. This method has been applied to two plasma machines (E.P.P.E. and SABLIER) for spatial and temporal measurements of the mean electron density. (author) [French] Nous avons etudie les caracteristiques d'un laser a gaz He-Ne utilise dans une technique simple d'interferometrie. La lumiere qui traverse le plasma est reinjectee dans le laser, et l'intensite propre de celui-ci, modulee par cette reinjection, sert a observer les franges. De plus, a cause du couplage des deux transitions laser: 0.63{mu} (rouge) et 3.39{mu} (infrarouge), les interferences dans l'infrarouge peuvent etre detectees par un simple photomultiplicateur sensible au rouge. Nous avons applique cette methode a deux machines a plasma (E.P.P.E. et SABLIER) pour la mesure de la densite electronique moyenne en fonction du temps et de l'espace. (auteur)

Responses of He-Ne laser on agronomic traits and the crosstalk between UVR8 signaling and phytochrome B signaling pathway in Arabidopsis thaliana subjected to supplementary ultraviolet-B (UV-B) stress.

Science.gov (United States)

Gao, Limei; Li, Yongfeng; Shen, Zhihua; Han, Rong

2018-05-01

UV-B acclimation effects and UV-B damage repair induced by a 632.8-nm He-Ne laser were investigated in Arabidopsis thaliana plants in response to supplementary UV-B stress. There was an increasing trend in growth parameters in the combination-treated plants with He-Ne laser and UV-B light compared to those stressed with enhanced UV-B light alone during different developmental stages of plants. The photosynthetic efficiency (Pn) and survival rates of seedlings were significantly higher in the combination treatments than UV-B stress alone. The expression of UVR8, phytochrome B (PhyB), and their mediated signal responsive genes such as COP1, HY5, and CHS were also significantly upregulated in plants with the laser irradiation compared with other groups without the laser. Levels of flavonol accumulation in leaves and capsule yield of He-Ne laser-treated plants were increased. The phyB-9 mutants were more sensitive to enhanced UV-B stress and had no obvious improvements in plant phenotypic development and physiological damage caused by enhanced UV-B stress after He-Ne laser irradiation. Our results suggested that UVR8 and its mediated signaling pathway via interaction with COP1 can be induced by He-Ne laser, and these processes were dependent on cytoplasmic PhyB levels in plant cells, which might be one of the most important mechanisms of He-Ne laser on UV-B protection and UV-B damage repair. These current data have also elucidated that the biostimulatory effects of He-Ne laser on Arabidopsis thaliana plants would happen not only during the early growth stage but also during the entire late developmental stage.

Effects of He-Ne laser irradiation on the storage of turkey semen

Directory of Open Access Journals (Sweden)

S. Passarella

2011-03-01

Full Text Available Maintenance or improvement of sperm quality during storage could prevent the loss of fertilizing capacity associated with stored turkey semen. Therefore the optimization of stored turkey semen could be useful to breeder industry since the commercial production of this bird relies almost entirely on artificial insemination. Previous research have shown that He-Ne laser irradiation in mammalian sperm increased the motility (Stato, 1986, decreased the mortality, promoted the acrosome reaction, which have a pivotal role in assisted fecundating programmes as therapy for resolving infertility in domestic animals..........

He-Ne and CW CO2 laser long-path systems for gas detection

Science.gov (United States)

Grant, W. B.

1986-01-01

This paper describes the design and testing of a laboratory prototype dual He-Ne laser system for the detection of methane leaks from underground pipelines and solid-waste landfill sites using differential absorption of radiation backscattered from topographic targets. A laboratory-prototype dual CW carbon dioxide laser system also using topographic backscatter is discussed, and measurement results for methanol are given. With both systems, it was observed that the time-varying differential absorption signal was useful in indicating the presence of a gas coming from a nearby source. Limitations to measurement sensitivity, especially the role of speckle and atmospheric turbulence, are described. The speckle results for hard targets are contrasted with those from atmospheric aerosols. The appendix gives appropriate laser lines and values of absorption coefficients for the hydrazine fuel gases.

Oscillatory behaviour of Rydberg state total cross sections in the collisions Ne+-He and He+-Ne

International Nuclear Information System (INIS)

Andresen, B.; Jensen, K.; Veje, E.

1976-01-01

The Ne + -He and He + -Ne collisions have been studied by means of optical spectrometry in the projectile energy range 10-150 keV. Very similar and regular oscillations in the Rydberg state total cross sections are found for HeI in both collisions and for singlet as well as triplet excitation. These oscillations are well described by the Rosenthal model. The HeI 4d sup(1,3)D states display two superimposed oscillations for center-of-mass collision energies above 6.4 keV. This is interpreted as the opening of a third exit channel, believed to be the HeI 4f sup(1,3)F. No, or very little structure is found in the Rydberg state total cross sections for HeII, NeI, NeII and NeIII levels. (Auth.)

He-Ne laser protection barrier by means of poly (Tetrafluoroethylene-Perfluoro vinyl Ether) grafted by acrylic acid complexed with Cu(II)

International Nuclear Information System (INIS)

El-Ahdal, M.A.; Fayek, S.A.; El-Sawy, N.M.

2006-01-01

Appropriate eye and skin protection is a prerequisite for the safe operation of He-Ne laser in industrial and laboratory environments. In the present paper, measurement of the optical parameters of poly (tetrafluoroethylene-perfluorovinyl ether) grafted by acrylic acid and complexed with Cu(II) are reported. He-Ne laser beam radiation on wavelength of 632.8 nm and power 12.5mW was used. Transmittance and reflectance spectra and refractive index dispersion are presented. The study showed that the material has a protective level 4. Environmental conditions like thermal and fading processes were tested. This suggested that the material preserves its protective features as a protective eye and skin barriers of protective level 4. This was applied for occupational working time up to 8 h, temperature up to 50 degree C and for a time equal 74 days after laser irradiation. Radiation protection from laser sources has attracted a great deal of attention for long time because of their importance for human body. Intensive progress in lasers, optical communications, and data storage has challenged scientists to achieve perfection in optical components. These challenges have resulted in an active development of a wide variety of unconventional optical elements (Hariharan, 1996 and Efimov et al., 2002). Alexandrite solid state lasers with a wavelength of about 755 nm are frequently used in the field of medicine (Schirmarcher and Sutter, 2001). For removing tattoos, the Q-switched versions with impulse widths of several ten nanoseconds are an ideal instrument to keep the thermal stress of the patient's skin at low level. He-Ne laser is one of the most commonly used visible light lasers

Changes in the ionic and protein contents of adult Schistocerca Gregaria compound eyes due to He-Ne laser exposure

International Nuclear Information System (INIS)

El-Gindi, A.M.; Osiris, W.G.; El-kes, N.; Abd El-Meguid, A.

1996-01-01

The induced change in the concentration of the ionic content such as Na, K, and Ca in the compound eyes of Schistocerca Gregaria was carried out before and after exposure for different periodic times to He-Ne ;laser beam. Total protein and albumin contents in the compound eyes were also determined. The Data indicated that the ionic contents (Na, K and Ca) showed acceptable and significant changes in both the right (R) and left (L) eyes after exposure to different periodic times up to 60 minutes in comparison with the control ones. Moreover, very high significant increase in the total protein content (about 70.2%) as well as significant decrease in the albumin content (about 39.1%) in the right (R) eyes after exposure to He-Ne laser beam for 30 minutes in comparison with the control (unexposed) eyes, were detected. 2 tabs

Study of He-Ne Laser Beam Propagation Through Air and Pure, Salt (Still and Turbulence Water

Directory of Open Access Journals (Sweden)

Safa AL. Barmany

2018-01-01

Full Text Available  This papers ,study  properties of the laser beam in the  different condition,  By using optical system consist of the (He- Ne laser ((λ =632.8nm , p=1.04mw, the parameter beam laser(spot, shape, intensity were study and also study the attenuation and turbulence for the laser mentioned above and with following environmental condition.(1 in the air (2 in the pure ,slate (seawaterwater with concentration 10-5Ml (still, turbulence  at different distance. Measurement were obtained by using a CCD camera and silicon detector type(Silicon PIN in fast response (.0.4-0.7A/W, absorption coefficient value of all cases  was calculated.

Diagnostics of ETL TPE-1 plasmas by using a He--Ne laser

Energy Technology Data Exchange (ETDEWEB)

Maejima, Y; Sugimoto, H; Tamaru, T [Electrotechnical Lab., Tanashi, Tokyo (Japan). Tanashi Branch

1975-08-01

The electron density in the plasma of toroidal screw pinch device TPE-1 of the Electrotechnical Laboratory has been measured with a conventional optical interferometer of He-Ne gas laser, 6,328 A in wavelength. The minimum phase shift detectable is about 1/300 lambda, equivalent to ..integral..nsub(e)dl=1x10/sup 15/cm/sup -2/. Some problems on this measuring system are presented. As the system uses conventional components, it is easy to construct and handle and is useful for determining plasma parameters in confinement experiments. The confinement time of charged particles is measured. As a result it has been found that the particles escape from the plasma mostly in conformity with the classical diffusion.

Quantitative description of the saturated absorption signal in iodine stabilized He-Ne lasers

International Nuclear Information System (INIS)

Brillet, A.; Cerez, P.

1977-01-01

He-Ne lasers stabilized by saturated absorption 127 I 2 have been studied in many laboratories and are now widely used as optical frequency standards. But, although their frequency stability and reproducibility have been extensively measured and reported, the size and the width of the saturated absorption signals used for the stabilization are not yet well understood. Particularly, the extrapolation of the linewidth to zero pressure results in an apparent discrepancy with the lifetime of the upper level of the transition. By measuring or evaluating all the important parameters which affect the operation of these lasers we are now able to describe with a good accuracy the properties of the saturated absorption signal and their variations with the iodine pressure, using Greenstein's theory of a laser with an internal absorption cell. At low iodine pressures (typically below 100 m Torr), we observe a divergence between experimental and theoretical results, which is interpreted as an effect of the laser beam geometry, when the saturation parameter becomes much larger than 1. (orig.) [de

Effect of He-Ne laser beam on the ommatidia in Schistocerca Gregaria

International Nuclear Information System (INIS)

Abd El-Meguid, A.

1996-01-01

Exposing compound eye of Schistocerca Gregaria to He-Ne laser beam affected the micro-environment of the eye. The results indicated that the ionic content (Na, K and Ca) decreased and showed measurable percentage changes about 21.3, 45.9 and 14.9% (very high significant, VHS) in the right (R); and about 32.1, 71.4 and 9.4% (VHS) in the left (L) left (L) eyes. Respectively. As compared with control (Unexposed) eyes. Also protein content showed increase in concentrations about 70.2% (VHS) and 60.0% (Hs) in both right (R) and left (L) eyes. Respectively. While albumin content showed significant (S) decrease in concentrations about 34.6 and 26.3% in both right (R) and left (L) eyes. Respectively, as compared with the control ones. Histological sections as well as scanning electron micrographs showed that exposure of eyes to laser beam affected the structure of the eyes. 4 figs., 2 tabs

Bullet Design and Fabrication of Dual Mode Pyroelectric Sensor: High Sensitive Energymeter for Nd: YAG Laser and Detector for Chopped He-Ne Laser

Directory of Open Access Journals (Sweden)

S. SATAPATHY

2008-05-01

Full Text Available Pyroelectric sensor using TGS has been designed and fabricated which can be operated in laser energy meter mode as well as pyroelectric detector mode. The amplifying circuit configuration has very good signal to noise ratio, very high input impedance and low drift. The pyroelectric sensor has been tested using Q-switched Nd: YAG laser and chopped He-Ne laser. The sensitivity of pyroelectric sensor in energymeter mode is 421.7V/J and the voltage responsivity of the pyroelectric sensor is 3.27 V/W in detector mode.

Phase control of a Zeeman-split He-Ne gas laser by variation of the gaseous discharge voltage.

Science.gov (United States)

Shelton, W N; Hunt, R H

1992-07-20

Zeeman-split lasers are useful for precise positioning or motion control. In applications that employ such a laser to control closely the position of a moving system, phase noise in the Zeeman frequency is a serious problem. Control of low-frequency phase noise can be obtained through variation of the external magnetic field by way of a solenoid wound around the laser tube. It is the finding in this work that control of the residual higher-frequency noise of a He-Ne laser can be obtained through small variations of the high voltage that is used to effect the gaseous discharge in the laser tube. The application of the present system is to the control of the path difference in a Fourier-transform interferometric spectrometer.

Treatment of relapse in herpes simplex on labial and facial areas and of primary herpes simplex on genital areas and "area pudenda" with low-power He-Ne laser or Acyclovir administered orally

Science.gov (United States)

Velez-Gonzalez, Mariano; Urrea-Arbelaez, Alejandro; Nicolas, M.; Serra-Baldrich, E.; Perez, J. L.; Pavesi, M.; Camarasa, J. M.; Trelles, Mario A.

1996-01-01

Sixty patients (greater than 16 yrs old) suffering primary or relapse genital herpes simplex viruses (HSV) and relapse labial HSV were appointed for this study. Three or more relapses were experienced per year. Patients (under treatment) were divided into two groups (distribution areas), corresponding to either labial herpes or genital herpes. These groups were sub-divided into 3 groups. The total number of labial or facial HSV patients was 36 (10 in group 1, 12 in group 2, 14 in group 3) and 24 for genital, buttocks, or 'area pudenda' HSV patients (6 in group 1, 8 in group 2, 10 in group 3). The design was a randomized, double- blind study. The setting was hospital and outpatient. The patients diagnosed as having the HVS disease were sent to the dermatology department and were assigned to a group at random. Treatment was begun as follows: During the treatment signs and symptoms were assessed and after the treatment, the relapses were also assessed (biochemical and hematological tests before and after the treatment) and the diagnosis of the HSV type I and II. The statistical evaluation of the results was performed and carried out with the SPSS and BMDP program. The relapses of the herpes infection in the lips and the face were significantly reduced (p less than 0.026) in patients treated with laser He-Ne and laser He-Ne plus Acyclovir. The interim between the relapses also increased significantly (p less than 0.005) in relation with the group treated with Acyclovir. The duration of the herpetic eruptions was clearly reduced in all locations in patients treated with laser He-Ne plus Acyclovir. No differences were noted between patients treated with laser He-Ne only or Acyclovir only. Therefore it is probable that therapeutic synergism took place. In relation with this, laser He-Ne shows the same therapeutic efficacy as Acyclovir taken orally. The association of Acyclovir and laser Ne-Ne could be an alternative method for the treatment of HSV in the face. The number

Optical power calibrator based on a stabilized green He-Ne laser and a cryogenic absolute radiometer

International Nuclear Information System (INIS)

Varpula, T.; Seppa, H.; Saari, J.M.

1989-01-01

This paper describes an optical power calibrator whose overall calibration uncertainty is less than 10 -4 for an optical power of 0.13 mW. The laser light source of the system operates at a wavelength of 543.5 nm, being close to the wavelength at which the candela is defined, 555 nm. A stable optical power is achieved by stabilizing the intensity and the frequency of a green He-Ne laser. The optical power is detected by a cryogenic absolute radiometer based on the principle of electrical substitution radiometry. It can be employed to measure optical power up to 0.5 mW in the visible and near infrared region

Investigation of an He-Ne laser generating a beam with a ring-shaped intensity distribution

Energy Technology Data Exchange (ETDEWEB)

Sukhanov, I I; Troitskii, IU V; Iakushkin, S V

1987-02-01

The paper examines an He-Ne laser regime with the simultaneous generation of TEM(01) and TEM(10) modes, forming a beam with a ring-shaped intensity distribution with total suppression of the TEM(00) mode. The ratio of the intensity at the ring crest to the intensity at the axis reached a value of 200 and was limited by scattering in the optical components of the resonator. A regime of mutual frequency locking of the TEM(01) and TEM(10) modes was achieved with total spatial coherence of the ring-shaped beam. 14 references.

Metastable He (n=2) - Ne potential interaction calculation

International Nuclear Information System (INIS)

Rahal, H.

1983-10-01

Diabatic potential terms corresponding to He (2 1 S)-Ne and He (2 3 S)-Ne interactions are calculated. These potentials reproduce the experimental results thermal metastable atom elastic scattering on Ne target. A model which reduces the interaction to a one-electron problem is proposed: the He excited electron. Its interaction with the He + center is reproduced by a ''l'' dependent potential model with a 1/2 behaviour at short range. The electron interaction facing the Ne is described by a l-dependent pseudopotential reproducing with accuracy the electron elastic scattering on a Ne atom. The importance of the corrective term related to the Ne polarizations by the electron and the He + ion is showed in this work. In the modelling problems, the accuracy cannot be better than 0.1 MeV [fr

Effect of He-Ne laser irradiation on hydrogen production by Enterobacter aerogenes

Energy Technology Data Exchange (ETDEWEB)

Lu, Wenyu; Wen, Jianping; Jia, Xiaoqiang; Sun, Bing; Chen, Yu.; Liu, Minhui [Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China)

2008-01-15

Enterobacter aerogenes W-23 bacteria exhibiting hydrogen production (HP) ability were exposed to He-Ne laser irradiation (632.8 nm) to improve the HP ability. Upon the optimum irradiation dosage (18 mW for 22.2 min), a stable positive mutant strain E. aerogenes HB-5M was obtained. The maximum specific rate of HP of the mutant strain was 0.042h{sup -1}, which was about twice that of the wild strain. It was suggested that the higher HP ability of the mutant strain might be presumably attributed to the enhancement of hydrogenase activity. In addition, the kinetic parameters of cell growth, substrate consumption and HP of the wild strain and its mutant strain were regressed to simulate the fermentation process of E. aerogenes. The simulated results agreed well with the experimental data. (author)

He-Ne laser effects on blood microcirculation. An in vivo study through laser doppler flowmetry; Efeito do laser de helio neonio sobre a microcirculacao sanguinea durante a reparacao tecidual. Estudo in vivo por meio de fluxometria laser doppler

Energy Technology Data Exchange (ETDEWEB)

Nunez, Silvia Cristina

2002-07-01

Blood microcirculation performs an important function in tissue repair process, as well as in pain control, allowing for greater oxygenation of the tissues and the accelerated expulsion of metabolic products, that may be contributing to pain. Low Intensity Laser Therapy (LILT) is widely used to promote healing, and there is an assumption that it is mechanism of action may be due to an enhancement of blood supply. The purpose of this study was to evaluate, using laser Doppler flowmetry (LDF), the stated effects caused by radiation emitted by a He-Ne laser ({lambda}=632.8 nm) on blood microcirculation during tissue repair. To this end, 15 male mice were selected and received a liquid nitrogen provoked lesion, above the dorsal region, and blood flow was measured periodically, during 21 days. Due to radiation emission by the LDF equipment, a control group was established to evaluate possible effects caused by this radiation on microcirculation. To evaluate the He-Ne laser effects, a 1.15 J/cm{sup 2} dose was utilized, with an intensity of 6 mW/cm{sup 2}. The results obtained demonstrate flow alterations, provoked by the lesion, and subsequent inflammatory response. There was no statistical difference between the studied groups. As per the analysis of the results there is no immediate effect due the radiation emitted by a He Ne laser on microcirculation, although a percentage increase was observed in day 7 on medium blood flow rate in irradiated specimens. New studies are necessary to validate the use of this wavelength, in order to promote beneficial alterations in blood supply in radiated areas. (author)

Analysis of the collagen birefringence and the relative attenuation coefficient of health and burned skin irradiated with linearly polarized He-Ne laser; Analise da birrefringencia do colageno e do coeficiente de atenuacao de amostras de pele sadia e queimada irradiadas pelo laser de He-Ne linearmente polarizado

Energy Technology Data Exchange (ETDEWEB)

Silva, Daniela de Fatima Teixeira da

2002-07-01

Low-intensity laser therapy is characterized by its ability to induce athermic effects and nondestructive photobiological processes. Although it has been in use for more than 40 years, this phototherapy is still not an established therapeutic modality. The objectives of this study were: to quantify the collagen fibers organization by polarized light microscopy in normal and burned skin samples at day 17 post-injury considering preferential axis as the animal's spinal column and aligning the linear laser polarization in two directions of polarization, parallel or perpendicular to this axis; to determine the relative attenuation coefficient for the intensity light by the technique of imaging the light distribution in normal and burned skin during wound healing process taking only parallel direction of polarization. To reach the objectives, burns about 6 mm in diameter were created with liquid N{sub 2} on the back of the rats and the lesions were irradiated on days 3, 7, 10 and 14 post-wounding, D= 1 J/cm{sup 2}, to investigate the effects of low-intensity linearly polarized He-Ne laser beam on skin wounds healing. Control lesions were not irradiated. The results have demonstrated that: the skin samples irradiated with linearly parallel polarized He-Ne laser beam showed collagen fibers more organized; burned skin samples presents a higher attenuation coefficient than normal skin samples. These results are important to optimize low intensity laser therapy dosimetry on acceleration wound healing. (author)

Experimental and theoretical basis of agricultural plant immunostimulation with regard to pathogenic fungi by magnetic field and He-Ne laser irradiation

Science.gov (United States)

Belski, Alexey I.; Chivanov, Vadym D.

1996-09-01

Spring barley, winter wheat and maize seeds were subjected to the action of He-Ne laser irradiation having a low intensity in the visible region of the spectrum (628-640 nm) in conjunction with magnetic fields. The following results were obtained: laser irradiation with magnetic fields induced activation of the natural plant defence/immune systems gave the harvest crop level increased to about 50- 300 percent; a correlation was established between the rate of the fungal pathogens growth and the stimulation of plant immunity after the seeds had been treated with laser irradiation and magnetic field.

Analysis of the collagen birefringence and the relative attenuation coefficient of health and burned skin irradiated with linearly polarized He-Ne laser

International Nuclear Information System (INIS)

Silva, Daniela de Fatima Teixeira da

2002-01-01

Low-intensity laser therapy is characterized by its ability to induce athermic effects and nondestructive photobiological processes. Although it has been in use for more than 40 years, this phototherapy is still not an established therapeutic modality. The objectives of this study were: to quantify the collagen fibers organization by polarized light microscopy in normal and burned skin samples at day 17 post-injury considering preferential axis as the animal's spinal column and aligning the linear laser polarization in two directions of polarization, parallel or perpendicular to this axis; to determine the relative attenuation coefficient for the intensity light by the technique of imaging the light distribution in normal and burned skin during wound healing process taking only parallel direction of polarization. To reach the objectives, burns about 6 mm in diameter were created with liquid N 2 on the back of the rats and the lesions were irradiated on days 3, 7, 10 and 14 post-wounding, D= 1 J/cm 2 , to investigate the effects of low-intensity linearly polarized He-Ne laser beam on skin wounds healing. Control lesions were not irradiated. The results have demonstrated that: the skin samples irradiated with linearly parallel polarized He-Ne laser beam showed collagen fibers more organized; burned skin samples presents a higher attenuation coefficient than normal skin samples. These results are important to optimize low intensity laser therapy dosimetry on acceleration wound healing. (author)

Determination of total polyphenolic content in red wines by means of the combined He-Ne laser optothermal window and Folin-Ciocalteu colorimetric assay

NARCIS (Netherlands)

Doka, O.; Bicanic, D.

2002-01-01

The He-Ne laser (632.8 nm) and the concept of optothermal window (OW), a variant of the open photoacoustic cell, were combined with the Folin-Ciocalteu colorimetry assay to quantitate phenolics in four red wines. The total polyphenolic content in selected red wines varied between 786 and 1630 mg/L

Mass spectrometer determinations of solar wind He, Ne, and Ar and radiation belt He

International Nuclear Information System (INIS)

Warasila, R.L.

1976-01-01

A unique mass spectrometer system was built and used to measure He, Ne, and Ar abundances and isotopic ratios in various samples of spacecraft that have been exposed to the space environment. The Apollo 12 mission brought back sections of the Surveyor 3 vehicle suitable for mass spectrometric studies of implanted solar wind and solar cosmic ray particles. Using the mass spectrometer, a 4 He flux of 6-8 x 10 6 ions/cm 2 --sec was measured, and in addition 4 He/ 3 He = 2700 +- 50; 4 He/ 20 Ne = 410 + 30; 20 Ne/ 22 Ne = 13.5 +- 0.2; 20 Ne/ 36 Ar = 24.5 +- 2.5; and 36 Ar/ 38 Ar = 5.41 +- 0.20 isotopic abundances were measured. An upper limit for the flux of SCR 3 He in the 10-20 MeV/nucleon range was also determined, for the thirty-one month exposure period. In the radiation belt environment, 3 He was found in the aluminum antenna housing from the recovered second stage of a pre-Apollo Saturn test flight launched January 28, 1964 and returned to earth on April 28, 1966. The amount of 3 He found was about 6 x 10 -10 cc(STP)/cm 2 with a 4 He/ 3 He ratio of 145 or less. The 3 He was shown to come from the lower radiation belt as all other sources of 3 He were orders of magnitude lower than the observed value

Histological study on the effect of He-Ne laser on the compound eyes of the locust Schistocerca Gregaria Forsk (Orthoptera-Acridiidae)

International Nuclear Information System (INIS)

Abd El-Meguid, A.; El-Gundi, A.M.; Osiris, W.G.; El-Kes, N.

1996-01-01

In the present study, the effect of the He-Ne laser beam at different exposure periods (10,30 and 60 minutes) on the histological structure of the compound eyes of Schistocerca Gregaria Forsk is investigated. This study shows that various remarkable changes occurred in the histological structure of the right exposed eye (R) as in the left eye (L) (unexposed eye of the same insect), which may be due to a change in the micro-environment of the compound eyes, affected by the laser beam, furthermore, damage in the photoreceptors of the compound eyes of the insect was observed. 23 figs

Flaking and blistering on He and Ne bombardments

International Nuclear Information System (INIS)

Kamada, K.; Naramoto, H.

1979-01-01

Large scale exfoliation formed by 300 keV He + bombardment of niobium without any preceding blistering is investigated, in comparison with the blistering due to 450 and 850 keV Ne + bombardments. In-situ observations of the erosion processes were performed in a scanning electron microscope connected to the Van de Graaff. Critical doses of 7.2 x 10 17 He + /cm 2 , 2.4 x 10 17 Ne + /cm 2 and 4.0 x 10 17 Ne + /cm 2 were obtained for the 300 keV He flaking, 450 keV Ne blistering and 850 keV Ne blistering, respectively. The He flaking was presumed to be due to brittle fashion peeling-off of the surface layer by the bending moment driven by the internal gas pressure. The blistering, on the other hand, was presumed to be the result of the ductile fashion spreading of the lenticular bubble in the sub-surface layer. The necessary pressure for the peeling-off of the cover was calculated, and was speculated to be able to work as the driving force for the flaking from its unexpectedly low values. Fractographies under the exfoliations were discussed for both flaking and blistering. (author)

Multichannel analysis of He*(21S)+Ne elastic and inelastic scattering in crossed atomic beams

International Nuclear Information System (INIS)

Martin, D.W.; Fukuyama, T.; Siska, P.E.

1990-01-01

State-to-state elastic and inelastic angular distribution and time-of-flight measurements are reported for the scattering of He*(2 1 S) by Ne in crossed supersonic atom beams at four collision energies in the range 0.6--2.8 kcal/mol. The inelastic collision products He+Ne*(nl), where nl=3d', 4p, 4p', 5s, 5s', and 4d, are scattered predominantly forward with respect to the direction of incidence, except for endothermic states near threshold. The data are analyzed with a numerically exact multichannel curve-crossing model that yields good agreement with experimental cross section branching fractions and total quenching and state-to-state rate constants as well as the angular measurements. The model suggests the importance of intermediate ''chaperone'' states, in which the excited electron is temporarily trapped in a d or f Rydberg Ne orbital, in channeling flux into the 4s' and 5s' upper laser states of Ne by energy transfer from He*(2s 1,3 S)

Third-order nonlinear optical studies of anthraquinone dyes using a CW He-Ne laser

Science.gov (United States)

Pramodini, S.; Poornesh, P.

2014-05-01

We present investigations on the third-order optical nonlinearity and optical power limiting of anthraquinone dyes. Z-scan measurements were performed using a continuous wave He-Ne laser at 633 nm wavelength as an excitation source. The nonlinear refraction studies exhibited self-defocusing behavior of the dyes. The nonlinear absorption in the dyes was dominated by a reverse saturable absorption process. Self-diffraction ring patterns were observed due to the change in refractive index and thermal lensing. Increase of the electron donating ability of the substituents resulted in enhanced values of the nonlinear optical parameters, establishing the structure-property relationship. The optical limiting study revealed that the dyes possess a lower limiting threshold and clamping level which is very important for eye and sensor protection. Hence, the dyes investigated here emerge as promising candidates for future opto-electronic and photonic device applications such as optical power limiters.

Effect of He-Ne laser irradiation of Bombyx mori L. breed in egg stage on thereproductive characters

International Nuclear Information System (INIS)

Ovesenska, L.; Vasileva, J.

1984-01-01

Two eggs of B. mori breeds were treated with laser rays at various rates. The effects of irradiation on the quantitative characters with alterating phenotypic performance characterizing the reproductive capability of the progeny was investigated. The characters were compared between parents and progeny as well as with control groups in the progeny. Data were processed by mono-factional analysis of variance of polugenic quantative characters with alternating phenotypic performance. Characterization of the characters was made by mean arithmetic value' analysis of the phenotype variance with the coeficient of genetic diversity in the investigated groups. A simulating effect of He-Ne laser irradiation on the reproductive characters of B. mori was found both in the parents and in their progeny. The effect was higher in breeds of lower reproductive capacity after treatment at lower rates (5, 10 and 15 mW), and the eggs treated were in a more advanced embrional stage

Recent Experiments Leading to the Characterization of the Performance of Portable (He-Ne)/CH4 Lasers: Part I: Results of the 1985 International Comparison BIPM-VNIIFTRI

Science.gov (United States)

Felder, R.; Chartier, J.-M.; Domnin, Yu S.; Oboukhov, A. S.; Tatarenkov, V. M.

1988-01-01

We analyse the results of beat-frequency measurements made on four (He - Ne)/CH4 lasers. It is found that the lack of reproducibility of the frequency of such standards is linked to the existence of various parameters whose relative influences lead to unpredicted experimental results.

Enhancing the healing processes of chemical burns with He-Ne radiation

International Nuclear Information System (INIS)

Kakai, S.F.K.; Albarwari, S.E.; Alsenawi, T.A.

1988-02-01

The process by which He-Ne laser radiation (λ = 632.8 nm) enhances the healing of cutaneous wounds, made by concentrated nitric acid on mice has been studied. The dose used was of the order of 2.7 Joule per day, till the day of complete wound closure. The wounds were irradiated at three points on its periphery so that to form a semitriangular pattern this method was adopted, because chemical burns involve the killing of both the epidermis and dermis. The influence of the laser on the healing was estimated quantitatively and statistically, with a significance of p<0.001 over the control (the unirradiated). (author). 8 refs, 2 figs, 2 tabs

Plate Tectonic Cycling and Whole Mantle Convection Modulate Earth's 3He/22Ne Ratio

Science.gov (United States)

Dygert, N. J.; Jackson, C.; Hesse, M. A.; Tremblay, M. M.; Shuster, D. L.; Gu, J.

2016-12-01

3He and 22Ne are not produced in the mantle or fractionated by partial melting, and neither isotope is recycled back into the mantle by subduction of oceanic basalt or sediment. Thus, it is a surprise that large 3He/22Ne variations exist within the mantle and that the mantle has a net elevated 3He/22Ne ratio compared to volatile-rich planetary precursor materials. Depleted subcontinental lithospheric mantle and mid-ocean ridge basalt (MORB) mantle have distinctly higher 3He/22Ne compared to ocean island basalt (OIB) sources ( 4-12.5 vs. 2.5-4.5, respectively) [1,2]. The low 3He/22Ne of OIBs approaches chondritic ( 1) and solar nebula values ( 1.5). The high 3He/22Ne of the MORB mantle is not similar to solar sources or any known family of meteorites, requiring a mechanism for fractionating He from Ne in the mantle and suggesting isolation of distinct mantle reservoirs throughout geologic time. We model the formation of a MORB source with elevated and variable 3He/22Ne though diffusive exchange between dunite channel-hosted basaltic liquids and harzburgite wallrock beneath mid-ocean ridges. Over timescales relevant to mantle upwelling beneath spreading centers, He may diffuse tens to hundreds of meters into wallrock while Ne is relatively immobile, producing a regassed, depleted mantle lithosphere with elevated 3He/22Ne. Subduction of high 3He/22Ne mantle would generate a MORB source with high 3He/22Ne. Regassed, high 3He/22Ne mantle lithosphere has He concentrations 2-3 orders of magnitude lower than undegassed mantle. To preserve the large volumes of high 3He/22Ne mantle required by the MORB source, mixing between subducted and undegassed mantle reservoirs must have been limited throughout geologic time. Using the new 3He/22Ne constraints, we ran a model similar to [3] to quantify mantle mixing timescales, finding they are on the order of Gyr assuming physically reasonable seafloor spreading rates, and that Earth's convecting mantle has lost >99% of its primordial

Analysis of the influence of low-power HeNe laser on the healing of skin wounds in diabetic and non-diabetic rats

Directory of Open Access Journals (Sweden)

Carvalho Paulo de Tarso Camillo de

2006-01-01

Full Text Available PURPOSE: To study the influence of HeNe laser irradiation on the collagen percentage in surgically-induced skin wounds in rats with and without alloxan-induced diabetes, by morphometric analysis of collagen fibers. METHODS: 48 male Wistar rats were used, divided into groups: laser-treated diabetic (group 1; untreated diabetic (group 2; treated non-diabetic (group 3; and untreated non-diabetic (group 4. For groups 1 and 2, diabetes was induced by intravenous injection of alloxan (2,4,5,6-tetraoxypyrimidine; 5,6-dioxyuracil; Sigma, into the dorsal vein of the penis, at a rate of 0.1 ml of solution per 100 g of body weight. A wound was made on the back of all the animals. Groups 1 and 3 were treated with HeNe laser (4 J/cm² for 60 s. One animal from each group was sacrificed on the 3rd, 7th and 14th days after wounding. Samples were taken, embedded in paraffin, stained with hematoxylin-eosin and Masson's trichrome, and morphometrically analyzed using the Imagelab software. The percentages of collagen fibers were determined from the samples from the euthanasia animals. The data were treated statistically using analysis of variance (ANOVA and the Student t and Kruskal-Wallis tests. The significance level was set at 0.05 or 5%. RESULTS: The results obtained from the samples taken on the third, seventh and fourteenth days after wounding demonstrated that the laser-treated group presented a statistically significant (p<0.05 greater mean quantity of collagen fibers than in the non-treated group, both for diabetic rats (p = 0.0104 and for non-diabetic rats (p = 0.039. CONCLUSION: The low-power laser (632.8 nm was shown to be capable of influencing the collagen percentage in skin wounds by increasing the mean quantity of collagen fibers, both for the diabetic and for the non-diabetic group.

Research on optical properties of dental enamel for early caries diagnostics using a He-Ne laser

Science.gov (United States)

Tang, Jing; Liu, Li; Li, Song-zhan

2008-12-01

A new and non-invasive method adapted for optical diagnosis of early caries is proposed by researching on the interaction mechanism of laser with dental tissue and relations of remitted light with optical properties of the tissue. This method is based on simultaneous analyses of the following parameters: probing radiation, backscattering and auto-fluorescence. Investigation was performed on 104 dental samples in vitro by using He-Ne laser (λ=632.8nm, 2.0+/-0.1mW) as the probing. Spectrums of all samples were obtained. Characteristic spectrums of dental caries in various stages (intact, initial, moderate and deep) were given. Using the back-reflected light to normalize the intensity of back-scattering and fluorescence, a quantitative diagnosis standard for different stages of caries is proposed. In order to verify the test, comparison research was conducted among artificial caries, morphological damaged enamel, dental calculus and intact tooth. Results show that variations in backscattering characteristic changes in bio-tissue morphological and the quantity of auto-fluorescence is correlated with concentration of anaerobic microflora in hearth of caries lesion. This method poses a high potential of diagnosing various stages of dental caries, and is more reliability to detect early caries, surface damage of health enamel and dental calculus.

Excitation of Li and Na atoms in collisions with He and Ne

International Nuclear Information System (INIS)

Olsen, J.Oe.; Andersen, T.; Andersen, N.

1977-01-01

Total emission cross sections and polarizations have been measured for the 2 2 S - 2 2 P, 2 2 P - 3 2 D and 2 2 P - 3 2 S LiI multiplets in Li - He,Ne collisions, and the 3 2 S - 3 2 P and 3 2 P - 3 2 D NaI multiplets in Na - He,Ne collisions in the 0.6 - 60 keV energy range. The excitation of the alkali resonance multiplet is found to be the dominant inelastic process for all four collision systems. The behaviour is very similar to the previously investigated Be + - He,Ne and Mg + - He,Ne systems. The results are compared with recent calculations by Manique et al based on a quasi-one electron description using various model potentials. Good agreement is found for Li - He with a simple Hartree-Fock frozen-core potential. The agreement is fair for Li,Na - He calculations with a Baylis type potential but poor for calculations based on Bottcher model potentials. For Ne as target all three potentials by far overestimate the size of the cross section. (Auth.)

Feasibility of Strong and Quasi-Monochromatic Gamma-Ray Generation by the Laser Compton Scattering

Energy Technology Data Exchange (ETDEWEB)

Lee, Jiyoung; Rehman, Haseeb ur; Kim, Yonghee [KAIST, Daejeon (Korea, Republic of)

2015-10-15

This is because LCS γ-rays are energy-tunable, quasi-monochromatic, and beam-like. The photon intensity of the mono-chromatic LCS gamma-ray should be high or strong for efficient and high transmutation rate. It was recently reported that a so-called energy-recovery linac system is able to produce a very high-intensity LCS photons in the order of approximately 1013 photons/s economically. It however did not evaluate quality of the LCS photon beam although a quasi-monoenergetic LCS beam is of huge importance in the photo-nuclear transmutation reactions. It is upon this observation that this paper was prepared. Specifically, this work attempts to quantify intensity of the quasi-monochromatic LCS beam from the said linac system. In addition, this paper aims to discuss general characteristics of the LCS photon, and possible approaches to increase its intensity. This paper presents essential characteristics of the laser Compton scattering (LCS) in terms of its photon energy, cross-section and photon intensity. By using different combinations of electron energy, laser energy and scattering angle, we can effectively generate high-intensity and highly-chromatic LCS gamma-rays. Our preliminary analyses indicate that, in view of Compton cross-section, higher-energy photon can be better generated by increasing the electron energy rather than increasing the laser energy. However, in order to maximize the intensity of monochromatic beam, the laser energy should be maximized for a targeted LCS photon energy.

Effect of conjugation length on nonlinear optical parameters of anthraquinone dyes investigated using He-Ne laser operating in CW mode

Science.gov (United States)

Pramodini, S.; Poornesh, P.

2014-10-01

We report the studies on third-order optical nonlinearity and optical limiting of anthraquinone dyes. Z-scan technique was employed to evaluate the nonlinear parameters such as nonlinear absorption coefficient βeff and nonlinear index of refraction n2. Continuous wave He-Ne laser was used as the source of excitation. The estimated values of βeff, n2 and χ(3) are of the order of 10-3 cm/W, 10-5 esu and 10-7 esu respectively. The presence of donor and acceptor groups in the structure results in increase in conjugation length. This resulted in the enhancement of nonlinear optical parameters values of the dye. Multiple diffraction rings were observed when the samples were exposed to laser beam due to thermal lensing. Dyes exhibited good optical limiting behavior under the experimental conditions. The results indicate that the dyes investigated here are materialise as candidates for photonics device applications such as optical power limiters.

Collision-induced intramultiplet mixing for the Ne**[(2p)5(3p)] + He or Ne system

International Nuclear Information System (INIS)

Manders, M.P.I.

1988-01-01

For the Ne**-He case, experimental data are confronted with quantum mechanical calculations. Quantum mechanical coupled-channel calculations using model potentials as input are presented, followed by a semiclassical approach which provides more physical insight. Experimental results are presented for the Ne**-Ne system with a discussion of the general principles involved in symmetrization. 184 refs.; 93 figs.; 19 tabs

Compressional behavior of solid NeHe2 up to 90 GPa

International Nuclear Information System (INIS)

Fukui, Hiroshi; Baron, Alfred Q R; Hirao, Naohisa; Ohishi, Yasuo

2010-01-01

NeHe 2 was compressed to about 90 GPa using a diamond anvil cell technique. The crystal structure was confirmed to be stable with hexagonal symmetry in the investigated pressure range and its p-V equation of state was determined by angular dispersive x-ray diffraction with synchrotron radiation. With the help of ab initio calculations, the compressibility and inter-atomic distances of NeHe 2 were compared with those of a helium and neon mixture of the same composition. This study shows that the bulk modulus of NeHe 2 is between those of neon and helium and that linear compressibilities of the inter-atomic distances are different from those of the elementary solids. This material can be a pressure-transmitting medium, providing both a large sample space and good quasi-hydrostatic conditions.

Measurements of line-averaged electron density of pulsed plasmas using a He-Ne laser interferometer in a magnetized coaxial plasma gun device

Science.gov (United States)

Iwamoto, D.; Sakuma, I.; Kitagawa, Y.; Kikuchi, Y.; Fukumoto, N.; Nagata, M.

2012-10-01

In next step of fusion devices such as ITER, lifetime of plasma-facing materials (PFMs) is strongly affected by transient heat and particle loads during type I edge localized modes (ELMs) and disruption. To clarify damage characteristics of the PFMs, transient heat and particle loads have been simulated by using a plasma gun device. We have performed simulation experiments by using a magnetized coaxial plasma gun (MCPG) device at University of Hyogo. The line-averaged electron density measured by a He-Ne interferometer is 2x10^21 m-3 in a drift tube. The plasma velocity measured by a time of flight technique and ion Doppler spectrometer was 70 km/s, corresponding to the ion energy of 100 eV for helium. Thus, the ion flux density is 1.4x10^26 m-2s-1. On the other hand, the MCPG is connected to a target chamber for material irradiation experiments. It is important to measure plasma parameters in front of target materials in the target chamber. In particular, a vapor cloud layer in front of the target material produced by the pulsed plasma irradiation has to be characterized in order to understand surface damage of PFMs under ELM-like plasma bombardment. In the conference, preliminary results of application of the He-Ne laser interferometer for the above experiment will be shown.

Dichromatic and monochromatic laser radiation effects on antibiotic resistance, biofilm formation, and division rate of Pantoea agglomerans

Science.gov (United States)

Thomé, A. M. C.; Souza, B. P.; Mendes, J. P. M.; Cardoso, A. F. R.; Soares, L. C.; Trajano, E. T. L.; Fonseca, A. S.

2018-06-01

Since infection is a common cause of delayed wound healing, it is important to understand the effect of low-level laser therapy (LLLT) in bacterial mechanisms. In this study we evaluated the effects of LLLT on antibiotic resistance, division rate, and biofilm formation of Pantoea agglomerans. P. agglomerans samples were isolated from human pressure injuries in humans and cultures were exposed to low-level monochromatic and simultaneous dichromatic laser radiation to study the susceptibility of an antimicrobial to ampicillin and piperacillin  +  tazobactam, quantification of areas of bacterial colonies, and biofilm formation of bacterial cells. Fluence, wavelength, and emission mode were used in the therapeutic protocols for wound healing. The data showed no changes in the areas of the colonies, but dichromatic laser radiation decreased biofilm formation, while a monochromatic red laser at low dose increased biofilm formation and infrared at high dose decreased antibiotic resistance to ampicillin. LLLT modulates antibiotic resistance and biofilm formation of P. agglomerans, but these depend on the laser irradiation parameters, since dichromatic laser radiation induces biological effects that differ from those induced by monochromatic laser radiation. Thus, simultaneous dichromatic low-level red and infrared lasers could be a new option for the treatment of infected wounds, reducing biofilm formation, without altering antibiotic resistance and the division rate of P. agglomerans cultures.

Photodynamic effect produced by HeNe radiation in Harderian glands of Wistar rats: an experimental model for PDT studies

Science.gov (United States)

dos Reis, Edmyr R.; Nicola, Ester M. D.; Metze, Konradin; Nicola, Jorge H.

2000-06-01

In rats, the Harderian Gland secret Protoporphirin IX which is retained at acinar lumina. Since this photosensitizer is important for PDT of malignant tumors, we propose to study this gland as a model to help understanding PDT with endogenous photosensitizers. Twenty Wistar SPF adult rats were submitted to surgical exposure of both Harderian glands, revealing red fluorescence upon UV, characterizing the protoporphirin IX presence. After that, one gland of each pair (one kept as control) was irradiated with an 8 mW HeNe (6328 angstrom) for 45 minutes, delivering about 2.7 joules/mm2. After 24 hours a group of 10 animals were scarified and the glands removed for histological analysis. The remaining animals were subjected to the same procedure but the glands were removed immediately after laser treatment. Histological and fluorescence analysis immediately after laser irradiation showed cell fragmentation with loss of acinar architecture with diffusion of protoporphirin in the cytoplasm of damaged cells, as well as interstitial edema. After 24 hours these alterations were more pronounced with accentuated loss of intraluminal protoporphirin and beginning of leukocytic demarcation of necrotic areas. The innate Harderian glands of rats, exposed to HeNe laser, showed a similar behavior as tumor tissue under PDT.

High-resolution monochromatic x-ray imaging system based on spherically bent crystals

International Nuclear Information System (INIS)

Aglitskiy, Y.; Lehecka, T.; Obenschain, S.; Bodner, S.; Pawley, C.; Gerber, K.; Sethian, J.; Brown, C.M.; Seely, J.; Feldman, U.; Holland, G.

1998-01-01

We have developed an improved x-ray imaging system based on spherically curve crystals. It is designed and used for diagnostics of targets ablatively accelerated by the Nike KrF laser. A spherically curved quartz crystal (2d=6.687 Angstrom, R=200 mm) has been used to produce monochromatic backlit images with the He-like Si resonance line (1865 eV) as the source of radiation. The spatial resolution of the x-ray optical system is 1.7 μm in selected places and 2 - 3 μm over a larger area. Time-resolved backlit monochromatic images of polystyrene planar targets driven by the Nike facility have been obtained with a spatial resolution of 2.5 μm in selected places and 5 μm over the focal spot of the Nike laser. copyright 1998 Optical Society of America

632 nm氦-氖激光治疗智齿冠周炎的研究%Study on 632 nm He-Ne laser therapy on pericoronitis

Institute of Scientific and Technical Information of China (English)

韦界飞; 邹群

2013-01-01

目的 通过临床试验,验证632 nm氦-氖红色激光对智齿冠周炎的镇痛效果和临床疗效.方法 选择下颌第3磨牙冠周炎患者75例,随机分为实验组和对照组.2组均采用局部常规治疗后,实验组用氦-氖激光局部照射15 min/d；对照组不再采取其他治疗.治疗后3、7d采用疼痛3度记分法记录消炎镇痛情况,并对2种治疗方法的效果进行综合评价.结果 治疗后3d,实验组78.9％患者疼痛消失,对照组51.4％患者疼痛消失；治疗后7d,实验组97.4％的患者疼痛消失,对照组91.9％的患者疼痛消失.治疗后3、7d,2组间疗效对比差异有统计学意义(P＜0.05).结论 氦-氖激光在治疗智齿冠周炎上具有明显的消炎镇痛效果.%Objective To investigate the effects of He-Ne laser on the treatment of pericoronitis.Methods 75 clinical patients with pericoronitis were randomly divided into the experimental group and control group.Local conventional therapy was given to the two groups.The experimental group was given routine treatment with He-Ne laser local exposure for 15 minutes every day,while the control group took no other treatment.3 days and 7 days later,pain and inflammation degree were recorded by three-degree pain scoring method.Total treatment effects were evaluated under a comprehensive clinical treatment standard.Results After 3 days' treatment,78.9％ patients in the experimental group and 51.4％ patients in control group felt their pain disappeared.After 7 days' treatment,97.4％ patients in experimental group and 91.9％ patients in control group felt their pain disappeared.Treatment comprehensive evaluation showed that there were statistical significance differences between two groups (P＜0.05).Conclusion He-Ne laser treatment of pericoronitis has significant anti-inflammatory analgesic effect.

Application of the EPR technique to examine free radical qualities reducing infection of spring wheat grain with pathogenic fungi by He-Ne laser irradiation

International Nuclear Information System (INIS)

Gagoś, M.; Koper, R.; Sujak, A.; Misiak, L.E.; Kowalczuk, E.

2000-01-01

Samples of spring wheat grain, Jasna cv., infected with pathogenic fungi (Aspergillus niger, Penicillium sp., Fusarium, Mucor) were examined using an EPR technique. Considering the quantity of generated free radicals the fungi belonged to most toxine generating. Their toxicity was connected with the number of free radicals generated in examined grain. Grain was irradiated with He-Ne laser at known wavelength, power density and time of exposure what gave the mycostatic effect appearing in decrease of free radicals in grain samples. However, this process was not stable as the increase of free radicals was observed again with the regrowth of fungi after some days

Determination of lactose in raw milks by means of the combined He-Ne laser optothermal window

NARCIS (Netherlands)

Bakos, P.; Doka, O.; Ajtony, Z.; Bicanic, D.; Szucs, D.

2002-01-01

The concept of OW (with 632.8 nm He–Ne laser), combined with colorimetry based on a reaction of anthrone-sulphuric acid, was proposed as a new tool for determination of lactose in raw milk. Data obtained from various milk samples by OW colorimetry were compared to those acquired from the MilkoScan

Theoretical prediction of the noble gas complexes HeAuF and NeAuF

Institute of Scientific and Technical Information of China (English)

无

2009-01-01

Ab initio calculations were carried out to investigate the structures and the stability of the noble gas complexes HeAuF and NeAuF through MP2 and CCSD(T) methods.The HeAuF was predicted to have a linear structure with weak He-Au covalent bonding,the distance of which is closer to the covalent limit in comparison with the corresponding van der Waals limit.The dissociation energy with respect to He + AuF was found to be 24 and 26 kJ·mol-1 at the CCSD(T)/basis set B and B’ levels,respectively.However,similar calculations for NeAuF indicate that NeAuF is not a stable species.

Higher coherent x-ray laser

International Nuclear Information System (INIS)

Hasegawa, Noboru; Nagashima, Keisuke; Kawachi, Tetsuya

2001-01-01

X-ray lasers generated by an ultra short pulse laser have advantages such as monochromatic, short pulse duration, small beam divergence, high intensity, and coherence. Spatial coherence is most important for applications, we have investigated the transient collisional excitation (TCE) scheme x-ray laser lasing from Ne-like titanium (31.6 nm), Ne-like silver (13.9 nm) and tin (11.9 nm). However, the spatial coherence was not so good with this scheme. We have been studying to improve the spatial coherence of the x-ray laser and have proposed to use coherent seed light tuned to the x-ray laser wavelength generated from higher harmonics generation (HHG), which is introduced to the x-ray laser medium (Ne-like titanium, Ni-like silver plasmas). We present about the theoretical study of the coupling efficiency HHG light with x-ray laser medium. (author)

Ratios of double to single ionization of He and Ne by strong 400-nm laser pulses using the quantitative rescattering theory

Science.gov (United States)

Chen, Zhangjin; Li, Xiaojin; Zatsarinny, Oleg; Bartschat, Klaus; Lin, C. D.

2018-01-01

We present numerical simulations of the ratio between double and single ionization of He and Ne by intense laser pulses at wavelengths of 390 and 400 nm, respectively. The yields of doubly charged ions due to nonsequential double ionization (NSDI) are obtained by employing the quantitative rescattering (QRS) model. In this model, the NSDI ionization probability is expressed as a product of the returning electron wave packet (RWP) and the total scattering cross sections for laser-free electron impact excitation and electron impact ionization of the parent ion. According to the QRS theory, the same RWP is also responsible for the emission of high-energy above-threshold ionization photoelectrons. To obtain absolute double-ionization yields, the RWP is generated by solving the time-dependent Schrödinger equation (TDSE) within a one-electron model. The same TDSE results can also be taken to obtain single-ionization yields. By using the TDSE results to calibrate single ionization and the RWP obtained from the strong-field approximation, we further simplify the calculation such that the nonuniform laser intensity distribution in the focused laser beam can be accounted for. In addition, laser-free electron impact excitation and ionization cross sections are calculated using the state-of-the-art many-electron R -matrix theory. The simulation results for double-to-single-ionization ratios are found to compare well with experimental data and support the validity of the nonsequential double-ionization mechanism for the covered intensity region.

Aquaporin-1-Mediated Effects of Low Level He-Ne Laser Irradiation on Human Erythrocytes

Directory of Open Access Journals (Sweden)

Gang-Yue Luo

2012-01-01

Full Text Available The role of membrane aquaporin-1 (APQ-1 in the photobiomodulation (PBM on erythrocyte deformability will be studied in this paper with human dehydrated erythrocytes as echinocytic shape alterations lead to decreased cellular deformability. Human dehydrated erythrocytes were irradiated with low intensity He-Ne laser irradiation (LHNL at 0.9, 1.8, 2.7, and 4.4 mW/cm2 for 5, 15, and 30 min, respectively, and APQ-1 inhibitor, 0.2 μmol/L HgCl2, was used to study the role of APQ-1 in mediating PBM with LHNL at 4.4 mW/cm2 for 5 min. Comprehensive morphological parameters of an intact cell such as contact area, perimeter, roundness and erythrocyte elongation index (EEI were measured to characterize erythrocyte deformability with fast micro multi-channel spectrophotometer. It was observed that the dosage of LHNL improvement of the morphological parameters of dehydrated erythrocytes was morphological-parameter-dependent, but the Bunsen-Roscoe rule did not hold for roundness. The LHNL at 4.4 mW/cm2 for 5 min significantly improved the contact area (P<0.05 and EEI (P<0.05 of the dehydrated erythrocytes, but the improvement was significantly inhibited by 0.2 μmol/L HgCl2 (P<0.05. It was concluded that AQP-1 might mediate the effects of LHNL on erythrocyte deformability, which supports the membranotropic mechanism of PBM.

Efeitos da aplicação do L.A.S.E.R. HeNe e do ultravioleta B no vitiligo

Directory of Open Access Journals (Sweden)

Ana Carolina Brandt de Macedo

Full Text Available INTRODUÇÃO: O vitiligo é uma doença crônica despigmentante da pele, ocasionada pela perda funcional dos melanócitos da epiderme. Este estudo teve como objetivo comparar os efeitos da aplicação do L.A.S.E.R. HeNe e do ultravioleta B em pacientes com vitiligo. MÉTODO: Foram selecionados 22 pacientes (11 mulheres e 11 homens, com idade entre 12 e 60 anos (31,68 ± 16,29. Os pacientes foram distribuídos aleatoriamente, de acordo com a ordem de comparecimento no serviço e foram divididos randomicamente em dois grupos: o grupo A (n = 12, submetido à aplicação do L.A.S.E.R. HeNe, para o qual a técnica utilizada foi a pontual com aproximadamente 3 cm de distância entre cada ponto, perpendicularmente à pele, e o grupo B (n = 10, exposto ao Ultravioleta B, aplicado de forma perpendicular com 10 cm de afastamento da pele do paciente. Para mensuração da área tratada, utilizou-se o programa AUTOCAD 2002, no qual foi delimitada a borda da mácula em fotos tiradas no início e no fim do tratamento. RESULTADOS: Inicialmente, no grupo A, a área era de 4,87 cm² ± 3,70 e, após a aplicação, foi de 4,15 cm² ± 2,89, com diferença média de 0,72 cm² (1,89. No grupo B, verificou-se que antes da aplicação a média era de 5,36 cm² ± 6,36 e, a após a aplicação, foi de 4,43 cm² ± 5,17, com diferença média de 0,92 cm² ± 1,29. CONCLUSÃO: Ambos os aparelhos obtiveram resultados significativos na redução da mácula, com maior redução no grupo da ultravioleta.

He-, Ne-, and Ar-phosgene intermolecular potential energy surfaces

DEFF Research Database (Denmark)

Munteanu, Cristian R.; Henriksen, Christian; Felker, Peter M.

2013-01-01

Using the CCSD(T) model, we evaluated the intermolecular potential energy surfaces of the He-, Ne-, and Ar-phosgene complexes. We considered a representative number of intermolecular geometries for which we calculated the corresponding interaction energies with the augmented (He complex) and doub...... of the complexes, providing valuable results for future experimental investigations. Comparing our results to those previously available for other phosgene complexes, we suggest that the results for Cl2-phosgene should be revised....

Quenching of 4He(21S,21P) and 3He(21S,21P) states by collisions with Ne(1S0) atoms

International Nuclear Information System (INIS)

Blagoev, K.B.; Dimova, E.; Petrov, G.M.

2004-01-01

The cross sections and rate constants for quenching 4 He(2 1 S), 4 He(2 1 P), 3 He(2 1 S) and 3 He(2 1 P) states by collisions with ground state Ne atoms are measured by a time-resolved method in a He-Ne electron beam excited plasma at low pressure. These rate constants at T g =600 K are: k 4 He(2 1 S) =(1.6±0.2)x10 -10 , k 4 He(2 1 P) =(3.4±2.5)x10 -10 , k 3 He(2 1 S) =(1.6±0.2)x10 -10 and k 3 He(2 1 P) =(5.7±1.2)x10 -10 cm 3 s -1 . The cross sections derived from the rate constant are σ 4 He(2 1 S) =(8.4±0.8)x10 -16 , σ 4 He(2 1 P) =(1.8±1.3)x10 -15 , σ 3 He(2 1 S) =(7.1±0.9)x10 -16 and σ 3 He(2 1 P) =(2.6±0.5)x10 -15 cm 2 , respectively. The diffusion coefficient of 3 He(2 1 S) in 3 He is estimated to be D 3 He(2 1 S)- 3 He =1.9D 4 He(2 1 S)- 4 He , based on comparison with 4 He. A time-dependent collisional radiative model for an e-beam sustained He-Ne plasma is developed and the predicted line intensity of NeI λ=6328 A line is compared with the experimental data. The influence of different processes involved in population and depopulation dynamics of He(2 1 S) state are evaluated

Interaction of Ne(2p54p), Ar(3p54p) and Kr(4p55p) excited atoms with He and Ne atoms. Processes of collisional depolarization

International Nuclear Information System (INIS)

Zagrebin, A.L.; Lednev, M.G.

1990-01-01

Quasimolecular terms Ne(2p 5 4p)+He, Ar(3p 5 4p)+He,Ne and Kr(4p 5 5p)+He,Ne are calculated within the framework of one-configuration method of effective Hamiltonian. The results of calculations agree with the experimental data

Advanced methods for nuclear reactor gas laser coupling

International Nuclear Information System (INIS)

Miley, G.H.; Verdeyen, J.T.

1978-06-01

Research is described that led to the discovery of three nuclear-pumped lasers (NPLs) using mixtures of Ne--N 2 , He--Hg, and He or Ne with CO or CO 2 . The Ne--N 2 NPL was the first laser obtained with modest neutron fluxes from a TRIGA reactor (vs fast burst reactors used elsewhere in such work), the He--Hg NPL was the first visible nuclear-pumped laser, while the Ne--CO and He--CO 2 lasers are the first to provide energy storage on a millisecond time scale. Important potential applications of NPLs include coupling and power transmission from remote power stations such as nuclear plants in satellites and neutron-feedback operation of inertial confinement fusion plants

Relativistic Dirac-Fock and many-body perturbation calculations on He, He-like ions, Ne, and Ar

International Nuclear Information System (INIS)

Ishikawa, Y.

1990-01-01

Relativistic Dirac-Fock and diagrammatic many-body perturbation-theory calculations have been performed on He, several He-like ions, Ne, and Ar. The no-pair Dirac-Coulomb Hamiltonian is taken as the starting point. A solution of the Dirac-Fock equations is obtained by analytic expansion in basis sets of Gaussian-type functions. Many-body perturbation improvements of Coulomb correlation are done to third order

A zone plate soft x-ray microscope using monochromatized undulator radiation at the beamline NE1B of the TRISTAN Accumulation Ring

International Nuclear Information System (INIS)

Wang, J.; Kagoshima, Y.; Miyahara, T.; Ando, M.; Aoki, S.; Anderson, E.; Attwood, D.; Kern, D.

1995-01-01

A soft x-ray microscope has been developed at the beamline NE1B of the 6.5-GeV TRISTAN Accumulation Ring (AR). It makes use of undulator radiation as its source and a zone plate with the outermost zone width of 50 nm as its imaging element. It has two main features. First, the undulator radiation is monochromatized by a grazing incidence grating monochromator to match to the monochromaticity requirement of the zone plate. Second, a visible light prefocus unit consisting of two objectives has been designed and installed in the x-ray microscope. The x-ray optical system of the microscope can be adjusted easily, quickly, and precisely by using this unit. The microscope can resolve 55-nm lines and spaces in a zone plate test pattern

International Comparison of Methane-Stabilized He-Ne Lasers

Science.gov (United States)

Koshelyaevskii, N. B.; Oboukhov, A.; Tatarenkov, V. M.; Titov, A. N.; Chartier, J.-M.; Felder, R.

1981-01-01

Two portable methane-stabilized lasers designed at BIPM have been compared with a type a stationary Soviet device developed in VNIIFTRI1. This comparison is one of a series aimed at establishing the coherence of laser wavelength and frequency measurements throughout the world and took place in June 1979. The VNIIFTRI and BIPM lasers using different methods of stabilization, have different optical and mechanical designs and laser tubes. The results of previous measurements, made in VNIIFTRI, of the most important frequency shifts for Soviet lasers together with a method of reproducing their frequency which leads to a precision of 1.10-12 are also presented.

High resolution monochromatic X-ray imaging system based on spherically bent crystals

International Nuclear Information System (INIS)

Aglitskiy, Y.; Lehecka, T.; Obenschain, S.; Bodner, S.; Pawley, C.; Gerber, K.; Sethian, J.; Brown, C. M.; Seely, J.; Feldman, U.; Holland, G.

1997-01-01

We have developed a new X-ray imaging system based on spherically curved crystals. It is designed and used for diagnostics of targets ablatively accelerated by the Nike KrF laser. The imaging system is used for plasma diagnostics of the main target and for characterization of potential backlighters. A spherically curved quartz crystal (2d=6.687 A, R=200 mm) is used to produce monochromatic backlit images with the He-like Si resonance line (1865 eV) as the source of radiation. The spatial resolution of the X-ray optical system is 3-4 μm. Time resolved backlit monochromatic images of CH planar targets driven by the Nike facility have been obtained with 6-7 μm spatial resolution

Determination of total polyphenolic content in red wines by means of the combined He-Ne laser optothermal window and Folin-Ciocalteu colorimetry assay.

Science.gov (United States)

Dóka, Ottó; Bicanic, Dane

2002-05-01

The He-Ne laser (632.8 nm) and the concept of optothermal window (OW), a variant of the open photoacoustic cell, were combined with the Folin-Ciocalteu colorimetry assay to quantitate phenolics in four red wines. The total polyphenolic content in selected red wines varied between 786 and 1630 mg/L gallic acid equivalent (GAE) as determined by OW-Folin-Ciocalteu colorimetry, which compares well to 778 and 1614 mg/L GAE obtained for the same wines by means of classical spectrophotometry. The originality and merit of OW colorimetry used here is that, unlike what is encountered in conventional spectrometry, no intermediate dilution step is required when total polyhenolics are determined in red wine. The precision, defined as the closeness to each other of 256 replicate readings of the OW signal, is generally better than 2%.

High resolution monochromatic X-ray imaging system based on spherically bent crystals

International Nuclear Information System (INIS)

Aglitskiy, Y.; Lehecka, T.; Obenschain, S.; Bodner, S.; Pawley, C.; Gerber, K.; Sethian, J.; Brown, C.M.; Seely, J.; Feldman, U.; Holland, G.

1997-01-01

We have developed a new X-ray imaging system based on spherically curved crystals. It is designed and used for diagnostics of targets ablatively accelerated by the Nike KrF laser [1,2]. The imaging system is used for plasma diagnostics of the main target and for characterization of potential backlighters. A spherically curved quartz crystal (2d=6.687 Angstrom, R=200mm) is used to produce monochromatic backlit images with the He-like Si resonance line (1865 eV) as the source of radiation. The spatial resolution of the X-ray optical system is 3 endash 4 μm. Time resolved backlit monochromatic images of CH planar targets driven by the Nike facility have been obtained with 6 endash 7 μm spatial resolution. copyright 1997 American Institute of Physics

Numerical simulation for nuclear pumped laser

Energy Technology Data Exchange (ETDEWEB)

Sakasai, Kaoru [Japan Atomic Energy Research Inst., Tokyo (Japan)

1998-07-01

To apply nuclear pumped laser of {sup 3}He-Ne-Ar gas to detect neutron, the optimum gas mixture was investigated by numerical simulation. When {sup 3}He-Ne-Ar mixture gas are irradiated by neutron, proton and triton with high velocity are produced by {sup 3}He(np)T and two charge particles ionized {sup 3}He, Ne and Ar which reacted each other and attained to 3p`(1/2){sub 0}-3S`(1/2). The calculation method is constructed by defining the rate equations of each ion and exited atom and the electron energy balance equation and by time integrating the simultaneous differential equations of the above two equations and the law of conservation of charge. Penning ionization and energy transport by elastic collision of neutral atom were considered in the transport process of electron energy direct ionization by secondary charge particle. Calculation time was 1 msec. The optimum component was shown 3 atm He, 24 Torr He and 8 Torr Ar by simulation. Laser oscilation was generated under the conditions 3.3 x 10{sup 14} (N/cm{sup 2}/5) thermal neutron flux at 50 cm laser cell length and 99% coefficient of reflection of mirror. After laser oscilation, laser output was proportional to neutron flux. These results showed nuclear pumped laser of {sup 3}He-Ne-Ar was able to detect optically neutron. (S.Y)

Repulsive wall potentials for He-(Ne,Ar,Kr,Xe) as inferred from differential cross sections

International Nuclear Information System (INIS)

Nitz, D.E.; Larson, J.; Swanson, K.; Wildgoose, C.

1993-01-01

We have obtained representations of the He-(Ne,Ar,Kr,Xe) ground state repulsive walls using model potentials optimized to fit published absolute differential cross section data for 500 and 1500 eV collisions. The HeNe potential, like the He 2 potentials can be fit using the semi-empirical HFD-B form constrained to cross zero at the proper internuclear separation. For the heavier atoms, this approach is unsuccessful and superior fits are obtained using only the purely repulsive V(r) - A EXP [-αr - βr 2 ] term of the HFD-B potential. Comparison of fitted potentials with previous results will be presented

Signal enhancement of neutral He emission lines by fast electron bombardment of laser-induced He plasma

Directory of Open Access Journals (Sweden)

Hery Suyanto

2016-08-01

Full Text Available A time-resolved spectroscopic study is performed on the enhancement signals of He gas plasma emission using nanosecond (ns and picosecond (ps lasers in an orthogonal configuration. The ns laser is used for the He gas plasma generation and the ps laser is employed for the ejection of fast electrons from a metal target, which serves to excite subsequently the He atoms in the plasma. The study is focused on the most dominant He I 587.6 nm and He I 667.8 nm emission lines suggested to be responsible for the He-assisted excitation (HAE mechanism. The time-dependent intensity enhancements induced by the fast electrons generated with a series of delayed ps laser ablations are deduced from the intensity time profiles of both He emission lines. The results clearly lead to the conclusion that the metastable excited triplet He atoms are actually the species overwhelmingly produced during the recombination process in the ns laser-induced He gas plasma. These metastable He atoms are believed to serve as the major energy source for the delayed excitation of analyte atoms in ns laser-induced breakdown spectroscopy (LIBS using He ambient gas.

Signal enhancement of neutral He emission lines by fast electron bombardment of laser-induced He plasma

Energy Technology Data Exchange (ETDEWEB)

Suyanto, Hery [Department of Physics, Faculty of Mathematics and Natural Sciences, Udayana University, Kampus Bukit Jimbaran, Denpasar 80361, Bali (Indonesia); Pardede, Marincan [Department of Electrical Engineering, University of Pelita Harapan, 1100 M.H. Thamrin Boulevard, Lippo Village, Tangerang 15811 (Indonesia); Hedwig, Rinda [Department of Computer Engineering, Bina Nusantara University, 9 K.H. Syahdan, Jakarta 14810 (Indonesia); Marpaung, Alion Mangasi [Department of Physics, Faculty of Mathematics and Natural Sciences, Jakarta State University, Rawamangun, Jakarta 12440 (Indonesia); Ramli, Muliadi [Department of Chemistry, Faculty of Mathematics and Natural Sciences, Syiah Kuala University, Darussalam, Banda Aceh 23111, NAD (Indonesia); Lie, Tjung Jie; Kurniawan, Koo Hendrik, E-mail: kurnia18@cbn.net.id [Research Center of Maju Makmur Mandiri Foundation, 40 Srengseng Raya, Kembangan, Jakarta Barat 11630 (Indonesia); Abdulmadjid, Syahrun Nur [Department of Physics, Faculty of Mathematics and Natural Sciences, Syiah Kuala University, Darussalam, Banda Aceh 23111, NAD (Indonesia); Tjia, May On [Research Center of Maju Makmur Mandiri Foundation, 40 Srengseng Raya, Kembangan, Jakarta Barat 11630 (Indonesia); Physics of Magnetism and Photonics Group, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, 10 Ganesha,Bandung 40132 (Indonesia); Kagawa, Kiichiro [Research Center of Maju Makmur Mandiri Foundation, 40 Srengseng Raya, Kembangan, Jakarta Barat 11630 (Indonesia); Fukui Science Education Academy, Takagi Chuo 2 chome, Fukui 910-0804 (Japan)

2016-08-15

A time-resolved spectroscopic study is performed on the enhancement signals of He gas plasma emission using nanosecond (ns) and picosecond (ps) lasers in an orthogonal configuration. The ns laser is used for the He gas plasma generation and the ps laser is employed for the ejection of fast electrons from a metal target, which serves to excite subsequently the He atoms in the plasma. The study is focused on the most dominant He I 587.6 nm and He I 667.8 nm emission lines suggested to be responsible for the He-assisted excitation (HAE) mechanism. The time-dependent intensity enhancements induced by the fast electrons generated with a series of delayed ps laser ablations are deduced from the intensity time profiles of both He emission lines. The results clearly lead to the conclusion that the metastable excited triplet He atoms are actually the species overwhelmingly produced during the recombination process in the ns laser-induced He gas plasma. These metastable He atoms are believed to serve as the major energy source for the delayed excitation of analyte atoms in ns laser-induced breakdown spectroscopy (LIBS) using He ambient gas.

Note: Diagnosing femtosecond laser-solid interactions with monochromatic Kα imager and x-ray pinhole camera

International Nuclear Information System (INIS)

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

2011-01-01

An x-ray pinhole camera and a monochromatic K α imager are used to measure the interactions of intense femtosecond laser pulses with Cu foil targets. The two diagnostics give different features in the spot size and the laser energy scaling, which are resulted from different physical processes. Under our experimental conditons, the K α emission is mainly excited by the fast electrons transporting inside the cold bulk target. In contrast, the x-ray pinhole signals are dominated by the broadband thermal x-ray emission from the hot plasma at the front target surface.

Combined tunable diode laser absorption spectroscopy and monochromatic radiation thermometry in ammonium dinitramide-based thruster

Science.gov (United States)

Zeng, Hui; Ou, Dongbin; Chen, Lianzhong; Li, Fei; Yu, Xilong

2018-02-01

Nonintrusive temperature measurements for a real ammonium dinitramide (ADN)-based thruster by using tunable diode laser absorption spectroscopy and monochromatic radiation thermometry are proposed. The ADN-based thruster represents a promising future space propulsion employing green, nontoxic propellant. Temperature measurements in the chamber enable quantitative thermal analysis for the thruster, providing access to evaluate thermal properties of the thruster and optimize thruster design. A laser-based sensor measures temperature of combustion gas in the chamber, while a monochromatic thermometry system based on thermal radiation is utilized to monitor inner wall temperature in the chamber. Additional temperature measurements of the outer wall temperature are conducted on the injector, catalyst bed, and combustion chamber of the thruster by using thermocouple, respectively. An experimental ADN thruster is redesigned with optimizing catalyst bed length of 14 mm and steady-state firing tests are conducted under various feed pressures over the range from 5 to 12 bar at a typical ignition temperature of 200°C. A threshold of feed pressure higher than 8 bar is required for the thruster's normal operation and upstream movement of the heat release zone is revealed in the combustion chamber out of temperature evolution in the chamber.

Laser Ablation of Biological Tissue Using Pulsed CO2 Laser

International Nuclear Information System (INIS)

Hashishin, Yuichi; Sano, Shu; Nakayama, Takeyoshi

2010-01-01

Laser scalpels are currently used as a form of laser treatment. However, their ablation mechanism has not been clarified because laser excision of biological tissue occurs over a short time scale. Biological tissue ablation generates sound (laser-induced sound). This study seeks to clarify the ablation mechanism. The state of the gelatin ablation was determined using a high-speed video camera and the power reduction of a He-Ne laser beam. The aim of this study was to clarify the laser ablation mechanism by observing laser excision using the high-speed video camera and monitoring the power reduction of the He-Ne laser beam. We simulated laser excision of a biological tissue by irradiating gelatin (10 wt%) with radiation from a pulsed CO 2 laser (wavelength: 10.6 μm; pulse width: 80 ns). In addition, a microphone was used to measure the laser-induced sound. The first pulse caused ablation particles to be emitted in all directions; these particles were subsequently damped so that they formed a mushroom cloud. Furthermore, water was initially evaporated by laser irradiation and then tissue was ejected.

Energy-Transfer Kinetics for Xe (6p[1/2]0) Atoms in Kr, Ar, Ne, and He.

Science.gov (United States)

He, Shan; Liu, Dong; Li, Xueyang; Chu, Junzhi; Guo, Jingwei; Liu, Jinbo; Hu, Shu; Sang, Fengting; Jin, Yuqi

2018-06-11

The kinetic processes for the Xe (6p[1/2] 0 ) atoms in Kr, Ar, Ne, and He buffer gases were studied. We found that Kr, Ar, and Ne atoms can be used to switch the amplified spontaneous emission (ASE) channel from 3408 nm (6p[1/2] 0 -6s'[1/2] 1 ) to 3680 nm (5d[1/2] 1 -6p[1/2] 1 ), while Xe and He atoms do not show such a phenomenon. This ASE channel switch is mainly ascribed to the fast transfer of 6p[1/2] 0 → 5d[1/2] 1 . On the basis of the rate equations for two-state coupling (energy-transfer processes between the two states are very rapid), the reason why the ASE channel switch effect normally coincides with a double exponential decay of the spontaneous emission at 828 nm (6p[1/2] 0 -6s[3/2] 1 ) is explained. The actual situations in Xe, Ar, Ne, and He follow this rule. However, the strictly single exponential decay of the spontaneous emission at 828 nm and strong ASE channel switch effect simultaneously emerge in Kr. This indicates that the transfer of 6p[1/2] 0 → 5d[1/2] 1 in Kr does not occur via two-state coupling, but via two steps of near-resonance collision through the 5s[3/2] 2 (Kr) state as the intermediate state (6p[1/2] 0 → 5s[3/2] 2 (Kr) → 5d[1/2] 1 ). In addition, we found Xe (6p[1/2] 0 ) atoms strongly tend to reach the 6p[3/2] 2 , 6p[3/2] 1 , and 6p[5/2] 2 states through the 5s[3/2] 2 (Kr) state as the intermediate state in Kr. The 5s[3/2] 2 (Kr) state plays a very important role in the energy-transfer kinetics for the Xe (6p[1/2] 0 ) atoms. Kr is probably an excellent buffer gas for laser systems based on Xe.

Laser image recording on detonation nanodiamond films

International Nuclear Information System (INIS)

Mikheev, G M; Mikheev, K G; Mogileva, T N; Puzyr, A P; Bondar, V S

2014-01-01

A focused He – Ne laser beam is shown to cause local blackening of semitransparent detonation nanodiamond (DND) films at incident power densities above 600 W cm -2 . Data obtained with a Raman spectrometer and low-power 632.8-nm laser source indicate that the blackening is accompanied by a decrease in broadband background luminescence and emergence of sharp Raman peaks corresponding to the structures of nanodiamond and sp 2 carbon. The feasibility of image recording on DND films by a focused He – Ne laser beam is demonstrated. (letters)

Laser image recording on detonation nanodiamond films

Energy Technology Data Exchange (ETDEWEB)

Mikheev, G M; Mikheev, K G; Mogileva, T N [Institute of Mechanics, Ural Branch of the Russian Academy of Sciences, Izhevsk (Russian Federation); Puzyr, A P; Bondar, V S [Institute of Biophysics, Siberian Branch of the Russian Academy of Sciences (Russian Federation)

2014-01-31

A focused He – Ne laser beam is shown to cause local blackening of semitransparent detonation nanodiamond (DND) films at incident power densities above 600 W cm{sup -2}. Data obtained with a Raman spectrometer and low-power 632.8-nm laser source indicate that the blackening is accompanied by a decrease in broadband background luminescence and emergence of sharp Raman peaks corresponding to the structures of nanodiamond and sp{sup 2} carbon. The feasibility of image recording on DND films by a focused He – Ne laser beam is demonstrated. (letters)

Study and optimisation of SIMS performed with He+ and Ne+ bombardment

International Nuclear Information System (INIS)

Pillatsch, L.; Vanhove, N.; Dowsett, D.; Sijbrandij, S.; Notte, J.; Wirtz, T.

2013-01-01

The combination of the high-brightness He + /Ne + atomic level ion source with the detection capabilities of secondary ion mass spectrometry (SIMS) opens up the prospect of obtaining chemical information with high lateral resolution and high sensitivity on the Zeiss ORION helium ion microscope (HIM). A feasibility study with He + and Ne + ion bombardment is presented in order to determine the performance of SIMS analyses using the HIM. Therefore, the sputtering yields, useful yields and detection limits obtained for metallic (Al, Ni and W) as well as semiconductor samples (Si, Ge, GaAs and InP) were investigated. All the experiments were performed on a Cameca IMS4f SIMS instrument which was equipped with a caesium evaporator and oxygen flooding system. For most of the elements, useful yields in the range of 10 −4 to 3 × 10 −2 were measured with either O 2 or Cs flooding. SIMS experiments performed directly on the ORION with a prototype secondary ion extraction and detection system lead to results that are consistent with those obtained on the IMS4f. Taking into account the obtained useful yields and the analytical conditions, such as the ion current and typical dwell time on the ORION HIM, detection limits in the at% range and better can be obtained during SIMS imaging at 10 nm lateral resolution with Ne + bombardment and down to the ppm level when a lateral resolution of 100 nm is chosen. Performing SIMS on the HIM with a good detection limit while maintaining an excellent lateral resolution (<50 nm) is therefore very promising.

3He functions in tokamak-pumped laser systems

International Nuclear Information System (INIS)

Jassby, D.L.

1986-10-01

3 He placed in an annular cell around a tokamak fusion generator can convert moderated fusion neutrons to energetic ions by the 3 He(n,p)T reaction, and thereby excite gaseous lasants mixed with the 3 He while simultaneously breeding tritium. The total 3 He inventory is about 4 kg for large tokamak devices. Special configurations of toroidal-field magnets, neutron moderators and beryllium reflectors are required to permit nearly uniform neutron current into the laser cell with minimal attenuation. The annular laser radiation can be combined into a single output beam at the top of the tokamak

Os efeitos do laser hélio-neônio de baixa intensidade na cicatrização de lesões cutâneas induzidas em ratos Effects of low-level helium-neon laser on induced wound healing in rats

Directory of Open Access Journals (Sweden)

Viviane L. Busnardo

2010-02-01

Full Text Available OBJETIVO: Avaliar os efeitos do laser de baixa potência hélio e neônio (HeNe na cicatrização de feridas cutâneas de ratos. MÉTODOS: Sessenta ratos Wistar foram divididos em grupos controle e experimento. Utilizou-se ferida incisional, longitudinal, dorso-mediana, suturada com pontos separados simples. No grupo experimento, as feridas foram irradiadas diariamente com aparelho de laser de HeNe com potência contínua máxima de 5mW, comprimento de onda de 632,8 nm, visível com densidade de energia de 4J/cm², área de raio do laser de 0,015cm², durante 36 segundos, em três pontos da lesão. As feridas foram avaliadas no 3º, no 7º e no 14º dia de pós-operatório. Cortes histológicos foram corados com hematoxilina-eosina (H&E e avaliados segundo protocolo de Vizzotto et al. (2003* para identificar o tipo de reação inflamatória e com Picrosirius para identificar os colágenos I e III e o índice de maturidade da cicatriz (IMaC. Utilizou-se imunoistoquímica com anti-CD45-LCA para o reconhecimento das células inflamatórias. RESULTADOS: Ambos os grupos mostraram o mesmo padrão inflamatório. No grupo experimento, observaram-se menos células inflamatórias nos três tempos estudados (pOBJECTIVE: To evaluate the effects of low-level helium-neon (HeNe laser on cutaneous wound healing in rats. METHODS: Sixty Wistar rats were divided into control group and experimental group. A sutured longitudinal, dorsal-medial incision was made, with simple separate stitches. The experimental group was irradiated daily in three areas of the wound with HeNe laser (5mW maximum continuous power, 632.8 nm wavelength, 4 J/cm² energy density and 0.015 cm² laser beam area for 36 seconds. The areas were evaluated on the third, seventh and fourteenth days postoperative. Histological sections were stained with hematoxylin-eosin to determine the type of inflammatory reaction according to the protocol by Vizzotto et al. (2003* and with Picrosirius to identify

Strangeness production in antiproton annihilation at rest on 3He, 4He and 20Ne

International Nuclear Information System (INIS)

Balestra, F.; Batusov, Yu.A.; Falomkin, I.V.; Pontecorvo, G.B.; Rozhdestvensky, A.M.; Sapozhnikov, M.G.; Tretyak, V.I.; Bendiscioli, G.; Filippini, V.; Rotondi, A.; Salvini, P.; Venaglioni, A.; Bossolasco, S.; Bussa, M.P.; Busso, L.; Fava, L.; Ferrero, L.; Panzieri, D.; Piragino, G.; Tosello, F.; Breivik, F.O.; Danielsen, K.M.; Jacobsen, T.; Soerensen, S.O.; Guaraldo, C.; Maggiora, A.; Haatuft, A.; Halsteinslid, A.; Myklebost, K.; Olsen, J.M.; Lodi Rizzini, E.; Brescia Univ.; Zenoni, A.; European Organization for Nuclear Research, Geneva

1991-01-01

New data are reported on antiproton annihilations at rest with production of Λ and K S 0 , using a streamer chamber with 3 He, 4 He and 20 Ne as gas targets. The data include Λ, K S 0 , ΛK S 0 and K S 0 K S 0 production rates and momentum distributions, π - momentum spectra, mean numbers of charged particles generally and of negatively charged particles separately for different reaction channels. The yields are compared to simple combinatorial calculations based on the extreme assumptions of Λ production via B=1 or via B=0 (anti K rescattering) annihilations. Λ and K S 0 momentum spectra are compared to simple model calculations where B=0 and B=1 annihilations with and without final-state interactions are considered. A review of existing data on Λ and K S 0 production is presented, showing the dependence on the anti p momentum and on the mass number of the target. (orig.)

Low-level laser therapy with helium-neon laser improved viability of osteoporotic bone marrow-derived mesenchymal stem cells from ovariectomy-induced osteoporotic rats

Science.gov (United States)

Fallahnezhad, Somaye; Piryaei, Abbas; Tabeie, Faraj; Nazarian, Hamid; Darbandi, Hasan; Amini, Abdoldllah; Mostafavinia, Ataroalsadat; Ghorishi, Seyed Kamran; Jalalifirouzkouhi, Ali; Bayat, Mohammad

2016-09-01

The purpose of this study was to evaluate the influences of helium-neon (He-Ne) and infrared (IR) lasers on the viability and proliferation rate of healthy and ovariectomy-induced osteoporotic (OVX) bone marrow mesenchymal stem cells (BMMSCs) in vitro. MSCs harvested from the BM of healthy and OVX rats were culture expanded. He-Ne and IR lasers were applied three times at energy densities of 0.6, 1.2, and 2.4 J/cm2 for BMMSCs. BMMSCs viability and proliferation rate were evaluated by MTT assay on days 2, 4, 6, 14, and 21. The results showed that healthy BMMSCs responded optimally to 0.6 J/cm2 using an IR laser after three times of laser radiation. Moreover, it was found that OVX-BMMSCs responded optimally to 0.6 J/cm2 with He-Ne laser and one-time laser radiation. It is concluded that the low-level laser therapy (LLLT) effect depends on the physiological state of the BMMSCs, type of the laser, wavelength, and number of laser sessions. The biostimulation efficiency of LLLT also depends on the delivered energy density. LLLT can enhance the viability and proliferation rate of healthy and especially osteoporotic autologous BMMSCs, which could be very useful in regenerative medicine.

Skin friction measurements using He-Ne laser

Energy Technology Data Exchange (ETDEWEB)

Choi, S.H. [Hankuk Aviation University Graduate School, Kyonggi-do (Korea, Republic of); Lee, Y. [Hankuk Aviation University, Kyonggi-do (Korea, Republic of)

1997-07-01

An experimental study of the skin friction measurement in a turbulent boundary-layer has been carried out. The skin friction measurements are made using the laser interferometer skin friction (LISF) meter, which optically detects the rate of thinning of an oil applied to the test surface. This technique produces reliable skin friction data over a wide range of flow situations up to 3-dimensional complicated flows with separation, where traditional skin friction measurement techniques are not applicable. The present measured data in a turbulent boundary-layer on a flat plate using the LISF technique shows a good comparison with the result from the previous velocity profile techniques, which proves the validity of the present technique. An extensive error analysis is carried out for the present technique yielding an uncertainty of about {+-}8%, which makes them suitable for CFD code validation purposes. Finally the measurements of the skin friction in a separated region after a surface-mounted obstacle are also presented. (author). 19 refs., 12 figs., 3 tabs.

Heterodyne interferometer laser source with a pair of two phase locked loop coupled He–Ne lasers by 632.8 nm

International Nuclear Information System (INIS)

Sternkopf, C; Diethold, C; Gerhardt, U; Manske, E; Wurmus, J

2012-01-01

Two He–Ne lasers are frequency and phase coupled by phase locking loop technique for a heterodyne laser interferometer. The heterodyne He–Ne laser is built of stabilized commercially used laser tubes. The two lasers create a high frequency stable heterodyne laser source with an output power of 2 mW. The laser source is coupled by two fibers (one fiber per laser) to the heterodyne laser head. This paper describes the configuration and the control theory basics of the laser system. The experimental setup and the equipment used are also described. First, experimental results with different parameters are represented. Then we discuss a novel heterodyne laser source which has achieved a master laser frequency stability of Δf 1 /f 1 = 1 · 10 −8 and a beat frequency stability of approximately Δf beat /f beat ≈ 4.5 · 10 −5 . (paper)

Few-Photon Multiple Ionization of Ne and Ar by Strong Free-Electron-Laser Pulses

International Nuclear Information System (INIS)

Moshammer, R.; Jiang, Y. H.; Rudenko, A.; Ergler, Th.; Schroeter, C. D.; Luedemann, S.; Zrost, K.; Dorn, A.; Ferger, T.; Kuehnel, K. U.; Ullrich, J.; Foucar, L.; Titze, J.; Jahnke, T.; Schoeffler, M.; Doerner, R.; Fischer, D.; Weber, T.; Zouros, T. J. M.; Duesterer, S.

2007-01-01

Few-photon multiple ionization of Ne and Ar atoms by strong vacuum ultraviolet laser pulses from the free-electron laser at Hamburg was investigated differentially with the Heidelberg reaction microscope. The light-intensity dependence of Ne 2+ production reveals the dominance of nonsequential two-photon double ionization at intensities of I 12 W/cm 2 and significant contributions of three-photon ionization as I increases. Ne 2+ recoil-ion-momentum distributions suggest that two electrons absorbing ''instantaneously'' two photons are ejected most likely into opposite hemispheres with similar energies

Imaging of exploding wire plasmas by high-luminosity monochromatic X-ray backlighting using an X-pinch radiation source

Energy Technology Data Exchange (ETDEWEB)

Pikuz, S A; Shelkovenko, T A; Romanova, V M [Russian Academy of Sciences, Moscow (Russian Federation). P.N. Lebedev Physical Inst.; Hammer, D A [Cornell Univ., Ithaca, NY (United States). Laboratory of Plasma Studies; Faenov, A Ya; Pikuz, T A [VNIIFTRI, Mendeleevo (Russian Federation). Multicharged Ions Spectral Data Center

1997-12-31

A new diagnostic method for dense plasmas, monochromatic x-ray backlighting, is described. In this method, shadow images of a bright, dense plasma can be obtained with high spatial resolution using monochromatic radiation from a separate plasma, permitting a major reduction in the required backlighting source power. The object plasma is imaged utilizing spherically bent mica crystals as the x-ray optical elements. Images of test objects obtained using x-ray radiation having different photon energies are presented. Shadow images of exploding Al wire plasmas in the ls{sup 2}-1s3p line radiation of He-like Al XII are also shown. Spatial resolution as fine as 4 {mu}m is demonstrated. The scheme described is useful for backlighting extended high density plasmas, and could be a less costly alternative to using X-ray lasers for such purposes. (author). 7 figs., 10 refs.

/sup 3/He functions in tokamak-pumped laser systems

Energy Technology Data Exchange (ETDEWEB)

Jassby, D.L.

1986-10-01

/sup 3/He placed in an annular cell around a tokamak fusion generator can convert moderated fusion neutrons to energetic ions by the /sup 3/He(n,p)T reaction, and thereby excite gaseous lasants mixed with the /sup 3/He while simultaneously breeding tritium. The total /sup 3/He inventory is about 4 kg for large tokamak devices. Special configurations of toroidal-field magnets, neutron moderators and beryllium reflectors are required to permit nearly uniform neutron current into the laser cell with minimal attenuation. The annular laser radiation can be combined into a single output beam at the top of the tokamak.

Pulsating instabilities and chaos in lasers

Energy Technology Data Exchange (ETDEWEB)

Harrison, R G; Biswas, D J

1985-01-01

A detailed state of the art survey of deterministic chaos in laser systems is presented. The mechanism of single mode instability is discussed, including spontaneous and induced mode splitting and the threshold for laser instabilities. Single mode homogeneously broadened systems are addressed, including optically pumped far infrared lasers and near-resonantly pumped midinfrared systems. Single mode inhomogeneously broadened systems are considered, including the He-Xe laser and the He-Ne laser at 3.39 microns. Single mode lasers with external control parameter are discussed, as is the multimode laser. 297 references.

Emission cross sections in low-energy collisions between He{sup +}, Ne{sup +} ions and CF{sub 4} molecule

Energy Technology Data Exchange (ETDEWEB)

Motohashi, Kenji; Takahashi, Tetsuro; Takahashi, Naruto; Tsurubuchi, Seiji [Department of Applied Physics, Tokyo University of Agriculture and Technology, 2-24-16 Koganei, Tokyo 184-8588 (Japan)

2005-09-28

Emission cross sections (Q{sub em}) of CF{sup +}{sub 4}(C-tilde - A-tilde, C-tilde - X-tilde; 200-500 nm), CF{sup +}{sub 4}(D-tilde - C-tilde, 350-440 nm), F(3p {sup 4}D{sup o}{sub 7/2}-3s {sup 4}P{sub 5/2}; 685.6 nm), He(3d {sup 3}D-2p {sup 3}P{sup o}; 587.6 nm), and Ne(3p {sup 2}[5/2]-3s {sup 2}[3/2]; 640.2 nm) produced in charge-exchange collisions between He{sup +} and Ne{sup +} and CF{sub 4} molecule were measured in the energy range below 5000 eV down to 1 eV (E{sub Lab}). Emission cross sections of F(3s {sup 2}P-2p{sup 5} {sup 2}P{sup o}; 95.5 nm) and F(3s {sup 4}P-2p{sup 5} {sup 2}P{sup o}; 97.5 nm) were also measured in He{sup +}+CF{sub 4}. No emission peaks were observed in the spectrum of Ar{sup +}+CF{sub 4} (E{sub Lab} = 2000 eV) in the wavelength range of 200-800 nm. The emission cross section of CF{sup +}{sub 4}(C-tilde - A-tilde, C-tilde - X-tilde; 200-500 nm) observed in Ne{sup +}+CF{sub 4} decreased with increasing the energy with a relation of Q{sub em} {proportional_to} E{sup -1/2}{sub CM} up to 60 eV, whereas it increased with increasing the energy above 100 eV. This result agreed well with one of Sasaki et al [1]. It was concluded that such dependence below 60 eV originated from an orbiting resonance into Ne+CF{sup +}{sub 4} (C-tilde{sup 2}T{sub 2}) channel. Emission cross sections of F, He and Ne rapidly increased with increasing the energy from the near thresholds.

Kinetic model of a Ne-H2 Penning Recombination Laser operating in the hollow cathode discharge

International Nuclear Information System (INIS)

Pramatarov, P.M.; Stefanova, M.S.; Petrov, G.M.

1995-01-01

The Penning Recombination Laser (PRL) requires the presence of both a recombination plasma populating the upper laser level (ULL) and a gas component efficiently depopulating the lower laser level (LLL) by Penning reactions. Such requirements are met in the negative glow plasma of a pulsed high voltage Ne-H 2 discharge with a helical hollow cathode. High rates of ionizations followed by recombinations are reached due to the beam component of non-Maxwellian electrons of 1-2 keV energy present in the tail of the electron energy distribution function. The H 2 , on the one hand plays the role of Penning component and on the other hand effectively cools the electrons by rotational and vibrational levels excitation. The latter contributes to the effectiveness of the recombination processes. A kinetic model of the physical processes determining the inversion population on the NeI(2p 1 -1s 2 ) transition (the 585.3 nm line) in a Ne-H 2 PRL operating in a high voltage hollow cathode discharge at intermediate pressures is proposed. About 60 plasma-chemical reactions are considered in the model. These include: two-electron recombination of Ne + ; dissociative recombination of Ne 2 + , NeH + and H 2 + ; ion-ion recombination of Ne + and H - ; Ne and H 2 direct ionization by fast electrons; Ne stepwise ionization; Penning ionization; Ne excitation by fast electrons; Ne stepwise excitation and de-excitation; radiative transitions; electron mixing between Ne excited states; H 2 rotational and vibrational levels excitation; H 2 dissociative attachment; elastic electron collisions with H 2 and Ne. The rate constants for the reactions are either taken from the literature or calculated in this work

Characteristics of a multi-keV monochromatic point x-ray source

Indian Academy of Sciences (India)

Temporal, spatial and spectral characteristics of a multi-keV monochromatic point x-ray source based on vacuum diode with laser-produced plasma as cathode are presented. Electrons from a laser-produced aluminium plasma were accelerated towards a conical point tip titanium anode to generate K-shell x-ray radiation.

Effect of laser on human blood

International Nuclear Information System (INIS)

Abdalsamad, Amuna Nagash Mohammed

2016-03-01

In this work, the effect of He-Ne (632.8 nm), N2 (337.1 nm), LED (450 nm) on the human blood, and blood component was studied by using CBC machine ( complete blood count) and UV -visible spectroscopy. Blood samples platoon A+ were collected and irradiated for different periods of time (10 minute, 20 minute, and 30 minute), to varied types of light source ( He- Ne laser and LED). Blood parameters of samples were measured by using complete Blood Count Machine (CBC). The absorption spectrum of blood samples were examined by using UV-visible spectrometer. The obtained results have shown different values of Complete Blood Counts and absorption spectrum due to different laser types and periods of time. We conclude that the laser light has clear effect on blood samples. (Author)

Physics of short-wavelength-laser design

Energy Technology Data Exchange (ETDEWEB)

Hagelstein, P.L.

1981-01-01

The physics and design of vuv and soft x-ray lasers pumped by ICF class high intensity infrared laser drivers are described (for example, the SHIVA laser facility at LLNL). Laser design and physics issues are discussed in the case of a photoionization pumping scheme involving Ne II and line pumping schemes involving H-like and He-like neon.

Product state resolved excitation spectroscopy of He-, Ne-, and Ar-Br2 linear isomers: experiment and theory.

Science.gov (United States)

Pio, Jordan M; van der Veer, Wytze E; Bieler, Craig R; Janda, Kenneth C

2008-04-07

Valence excitation spectra for the linear isomers of He-, Ne-, and Ar-Br2 are reported and compared to a two-dimensional simulation using the currently available potential energy surfaces. Excitation spectra from the ground electronic state to the region of the inner turning point of the Rg-Br2 (B,nu') stretching coordinate are recorded while probing the asymptotic Br2 (B,nu') state. Each spectrum is a broad continuum extending over hundreds of wavenumbers, becoming broader and more blueshifted as the rare gas atom is changed from He to Ne to Ar. In the case of Ne-Br2, the threshold for producing the asymptotic product state reveals the X-state linear isomer bond energy to be 71+/-3 cm(-1). The qualitative agreement between experiment and theory shows that the spectra can be correctly regarded as revealing the one-atom solvent shifts and also provides new insight into the one-atom cage effect on the halogen vibrational relaxation. The measured spectra provide data to test future ab initio potential energy surfaces in the interaction of rare gas atoms with the halogen valence excited state.

Erythrocyte sedimentation as detected by He:Ne laser

International Nuclear Information System (INIS)

Abdulla, M. M.; Al-Ani, F. S.; Al-Ani, A.

2005-01-01

Aggregation of erythrocytes is a reversable dynamic process. The growth process of three dimensional - chain - like aggregates depends on the shape of the cell available for the attachment. A study of red blood cell aggregation and sedimentation was performed for sample of 5% and 10% red blood cells in plasma, with macromolecules and without macromolecules. The analysis was studied under dynamic conditions by applying the method of back scattering laser light. The aggregation and reorientation of red blood cells was recorded via X-Y recorder connected to a sensitive photo diode. The records decleared the phases of the process as a function of time and amplitude. The amplitude of light signal depends on the size of aggregates and concentration of sample. The time intervals of different phases of aggregation and sedimentation were measured and the contribution of macromolecule substance in the plasma was analysed. (author)

Projectile charge dependence of the ionisation spectra for H sup + and sup 3 He sup 2+ ions on He and Ne atoms

Energy Technology Data Exchange (ETDEWEB)

Bernardi, G.; Garibotti, C.R.; Suarez, S. (Comision Nacional de Energia Atomica, San Carlos de Bariloche (Argentina). Centro Atomico Bariloche Consejo Nacional de Investigaciones Cientificas y Tecnicas, Buenos Aires (Argentina)); Fainstein, P. (Comision Nacional de Energia Atomica, San Carlos de Bariloche (Argentina). Centro Atomico Bariloche)

1990-05-14

The spectra of electrons emitted in the collisions of H{sup +} and {sup 3}He{sup 2+} on He at 50 and 100 keV, and on Ne gas at 100 keV were studied. For fixed angle the double differential cross section is analysed as a function of the velocity variable, which has a maximum about halfway between the soft electron and the electron capture to continuum peaks. The experimental results show that the position of this maximum does not depend on the projectile charge. Calculations using the continuum-distorted-wave-eikonal-initial-state approximation are in qualitative agreement with our measurements. (author).

Multiple electron processes of He and Ne by proton impact

Science.gov (United States)

Terekhin, Pavel Nikolaevich; Montenegro, Pablo; Quinto, Michele; Monti, Juan; Fojon, Omar; Rivarola, Roberto

2016-05-01

A detailed investigation of multiple electron processes (single and multiple ionization, single capture, transfer-ionization) of He and Ne is presented for proton impact at intermediate and high collision energies. Exclusive absolute cross sections for these processes have been obtained by calculation of transition probabilities in the independent electron and independent event models as a function of impact parameter in the framework of the continuum distorted wave-eikonal initial state theory. A binomial analysis is employed to calculate exclusive probabilities. The comparison with available theoretical and experimental results shows that exclusive probabilities are needed for a reliable description of the experimental data. The developed approach can be used for obtaining the input database for modeling multiple electron processes of charged particles passing through the matter.

Excitation processes in slow K+--He, Ne, Ar, H2, N2 and Na+--He collisions

International Nuclear Information System (INIS)

Kikiani, B.I.; Gochitashvili, M.R.; Kvizhinadze, R.V.; Ankudinov, V.A.

1984-01-01

Quasimolecular features of excitation processes in K + --He, Ne, Ar, H 2 , N 2 and Na + --He collisions were investigated by measuring the cross sections for the emission of the resonance lines of potassium (lambda = 766.5 and 769.9 nm), sodium (lambda = 589 and 589.6 nm), and helium (lambda = 584 nm) atoms at ion energies in the range 0.5--10 keV. In Na + --He collisions, the resonance-line excitation functions obtained for sodium and helium atoms exhibit oscillations that are in antiphase and are due to phase interference between the quasimolecular states of the system of colliding particles. Experimental data on K + --Ar collisions are interpreted in terms of schematic correlation diagrams for molecular orbitals. The excitation mechanisms for K + --N 2 and K + --Ar have beenfound to be similar, and this leads to the conclusion that the quasimolecular model used for the ion-atom case is also valid for the ion-molecule case. It is shown that the excitation of the 4p-state of the potassium atom in the K + --Ar case is due to a Landau-Zener type of interaction in the region of the quasicrossing of (KAr) + terms. Analysis of the excitation of this state in K + --N 2 collisions also shows that the capture of an electron into the excited 4p-state of the potassium atom is due to a nonadiabatic transition in the region of quasicrossing of energy terms of the same symmetry

Study of Interaction of Low-Energy Antiprotons with H$^{2}$,He$^{3}$,He$^{4}$,Ne-Nuclei Using a Streamer Chamber in Magnetic Field

CERN Multimedia

2002-01-01

The aim of this experiment is the systematic study of the interaction between low-energy antiprotons and the H|2,~He|3,~He|4,~Ne-nuclei using a self shunted streamer chamber in a magnetic field exposed to the antiproton beam of the LEAR facility. The properties of the self shunted streamer chamber, which allows the use of the filling gas (hydrogen, helium, neon at a pressure of l~atm) as a target, permit to carry out experiments also in the very low-energy region. \\\\ \\\\ The experimental apparatus is suitable for a large programme of measurements. We plan to measure the @*H|2 cross section and the spectator momentum distributions at @* momenta lower than 250~MeV/c, where data are lacking. It is interesting to study for the first time the @*He|3 and @*He|4 interactions measuring the cross sections and the emitted particle distributions. Among other things the knowledge of the branching ratio of the @*He|4 annihilation channels clarifies some open cosmological questions. The study of the process of nuclear absor...

A high-resolution study of the sup 20 Ne( sup 3 He,t) sup 20 Na reaction and the sup 19 Ne(p,. gamma. ) sup 20 Na reaction rate

Energy Technology Data Exchange (ETDEWEB)

Smith, M S; Magnus, P V; Hahn, K I; Howard, A J; Parker, P D [A.W. Wright Nuclear Structure Lab., Yale Univ., New Haven, CT (United States); Champagne, A E; Mao, Z Q [Dept. of Physics, Princeton Univ., NJ (United States)

1992-01-13

A high-precision measurement of the {sup 20}Ne({sup 3}He,t){sup 20}Na reaction has been made using implanted {sup 20}Ne transmission targets to obtain pertinent information on the low-energy resonances in the {sup 19}Ne(p,{gamma}){sup 20}Na reaction. Resonance energies (447{+-}5, 658{+-}5, 787{+-}5, and 857{+-}5 keV) and upper limits on total intrinsic widths (<10, <6, <10, and <16 keV) have been measured for four excited states above the 2.199 MeV proton threshold in {sup 20}Na. The stellar {sup 19}Ne(p,{gamma}){sup 20}Na reaction rate is calculated for temperatures between 1x10{sup 8} and 1x10{sup 9} K. When combined with a recent study of the {sup 15}O({alpha},{gamma}){sup 19}Ne reaction, a new estimate is made of the conditions required for breakout from the Hot CNO cylce to the rapid proton capture process. (orig.).

Spin-polarized 3He nuclear targets and metastable 4He atoms by optical pumping with a tunable, Nd:YAP laser

International Nuclear Information System (INIS)

Bohler, C.L.; Schearer, L.D.; Leduc, M.; Nacher, P.J.; Zachorowski, L.; Milner, R.G.; McKeown, R.D.; Woodward, C.E.

1988-01-01

Several Nd:YAP lasers were constructed which could be broadly tuned in the 1083-nm region which includes the helium 2 3 S-2 3 P transition, using a Lyot filter and thin, uncoated etalons within the laser cavity. 1 W of power could be extracted at 1083 nm through a 1% transmitting output coupler. This laser beam was used to optically pump metastable 4 He and 3 He 2 3 S helium atoms in a weak discharge cell, spin polarizing the metastable ensemble. In a 3 He cell the polarization is transferred to the nuclear spin system. A 3 He target cell at 0.3 Torr was polarized to 52% in a few minutes. We describe the application of this system to the design of polarized targets for experiments in nuclear physics

Strangeness production in antiproton annihilation at rest on sup 3 He, sup 4 He and sup 20 Ne

Energy Technology Data Exchange (ETDEWEB)

Balestra, F. (Cagliari Univ. (Italy). Dipt. di Scienze Fisiche Istituto Nazionale di Fisica Nucleare, Cagliari (Italy)); Batusov, Yu.A.; Falomkin, I.V.; Pontecorvo, G.B.; Rozhdestvensky, A.M.; Sapozhnikov, M.G.; Tretyak, V.I. (Joint Inst. for Nuclear Research, Dubna (USSR)); Bendiscioli, G.; Filippini, V.; Rotondi, A.; Salvini, P.; Venaglioni, A. (Pavia Univ. (Italy). Dipt. di Fisica Nucleare e Teorica Istituto Nazionale di Fisica Nucleare, Pavia (Italy)); Bossolasco, S.; Bussa, M.P.; Busso, L.; Fava, L.; Ferrero, L.; Panzieri, D.; Piragino, G.; Tosello, F. (Turin Univ. (Italy). Ist. di Fisica Generale Istituto Nazionale di Fisica Nucleare, Turin (Italy)); Breivik, F.O.; Danielsen, K.M.; Jacobsen, T.; Soerensen, S.O. (Oslo Univ. (Norway). Physics Dept.); Guaraldo, C.; Maggiora, A. (Istituto Nazionale di Fisica Nucleare, Frascati (Italy). Lab. Nazionale di Frascati); Haatuft, A.; Halsteinslid, A.; Myklebost, K.; Olsen, J.M. (Bergen Univ. (Norway). Dept. of Physics); Lodi Rizzini,

1991-05-13

New data are reported on antiproton annihilations at rest with production of {Lambda} and K{sub S}{sup 0}, using a streamer chamber with {sup 3}He, {sup 4}He and {sup 20}Ne as gas targets. The data include {Lambda}, K{sub S}{sup 0}, {Lambda}K{sub S}{sup 0} and K{sub S}{sup 0}K{sub S}{sup 0} production rates and momentum distributions, {pi}{sup -} momentum spectra, mean numbers of charged particles generally and of negatively charged particles separately for different reaction channels. The yields are compared to simple combinatorial calculations based on the extreme assumptions of {Lambda} production via B=1 or via B=0 (anti K rescattering) annihilations. {Lambda} and K{sub S}{sup 0} momentum spectra are compared to simple model calculations where B=0 and B=1 annihilations with and without final-state interactions are considered. A review of existing data on {Lambda} and K{sub S}{sup 0} production is presented, showing the dependence on the anti p momentum and on the mass number of the target. (orig.).

Density and temperature diagnostics of a Ne-like germanium plasma created by laser

International Nuclear Information System (INIS)

Berthier, E.; Bourgade, J.L.; Combis, P.; Jacquemot, S.; Le Breton, J.P.; Louis-Jacquet, M.; Naccache, D.; Nail, M.; Peyrusse, O.

1987-01-01

In the framework of X-ray laser studies, experiments on Ne-like Ge plasma have been performed by laser irradiation at λ = 1.053 μm. Amplification in lasing transitions has been observed by varying the plasma length. Theoretical calculations of excited level population allow us to determine density and temperature from line intensity ratios

低能量He-Ne激光血管内照射治疗肿瘤疼痛的临床观察%The clinical observation of treatment with He-Ne laser of low energy cancer pain

Institute of Scientific and Technical Information of China (English)

王丽芬; 关兴惠

2001-01-01

Treatment with He-Ne laser of low energy is new method.The way was directly shining irradiate blood.Biological effects were widespread.That can enhance immunity function and controlpain of cancer.By cleanins harmful matlers in the blood and changing composition of blood.We obtained yield good results in improving immunity of body and function of oryans.The cases were gotten from 1999 to 2000 year.%低能量He-Ne激光血管内照射(ILIB)是一种新的治疗技术，是将低能量激光导入血液系统直接照射血液，产生广泛良好的生物效应。ILIB疗法具有提高机体免疫功能及控制癌性疼痛的两种特性；对清除血液内有害的中分子物质(MMS)改善血液流变学特性对癌症患者有重要的治疗作用。多样的生物学效应可纠正癌症对机体脏器功能和免疫系统功能造成的损害。我科自1999年12月将这一新技术用于治疗顽固性癌性疼痛，提高患者的免疫力，改善各脏器的功能，作为化疗的辅助治疗。收到了意想不到的效果，报告如下。

He-Ne laser treatment for 16 cases of nonspecific edema

Science.gov (United States)

Xia, Wenlou; Liu, Sixian; Cao, Guangyi; Chen, Zhifu; Zhang, Haishui; Wei, Wei; Xia, Xinshe; Sia, Guangyu

1993-03-01

Nonspecific edema is a syndrome which is caused by a metabolism disorder of sodium and water. The people who suffer with this are mostly women about 25 - 50 years old. When it happens periodic edema, abdominal distension acratia, and obesity accompany the disease. Through several means of examination, no organic disease was found in the heart, liver, or kidney. Now 16 edema cases have been irradiated with laser and the result is satisfactory. The results are reported in this paper.

Gas discharge laser and method of manufacturing same

International Nuclear Information System (INIS)

Haans, P.F.A.

1975-01-01

On a thick-walled capillary tube rounded edges are pressed at either end. Double-conical surfaces are ground on the rounded edges so that a fitting edge which is very obtuse in cross-section is obtained for laser mirrors of a He-Ne laser of an economic construction

Production of He-, Ne-, Ar-, Kr-, and Xe-isotopes by proton-induced reactions on lead

International Nuclear Information System (INIS)

Leya, I.; Michel, R.

2003-01-01

We measured integral thin target cross sections for the proton-induced production of He-, Ne-, Ar-, Kr-, and Xe-isotopes from lead from the respective reaction thresholds up to 2.6 GeV. The production of noble gas isotopes in lead by proton-induced reactions is of special importance for design studies of accelerator driven systems and energy amplifiers. In order to minimise the influences of secondary particles on the production of residual nuclides a new Mini-Stack approach was used instead of the well-known stacked-foil techniques for all experiments with proton energies above 200 MeV. With some exceptions our database for the proton-induced production of noble gas isotopes from lead is consistent and nearly complete. In contradistinction to the production of He from Al and Fe, where the cross sections obtained by thin-target irradiation experiments are up to a factor of 2 higher than the NESSI data, both datasets agree for the He production from lead. (orig.)

Laser beam-forming by deformable mirror for laser isotope separation

International Nuclear Information System (INIS)

Nemoto, Koshichi; Fujii, Takashi; Goto, Naohiko

1995-01-01

A rectangular laser beam of uniform intensity is very suitable for laser isotope separation. In this paper, we propose a beam-forming system which consists two deformable mirrors. One of the mirrors changes the beam intensity and the other compensates for phase distortion. We developed a deformable mirror for beam-forming. Its deformed surface is similar to the ideal mirror surface for beam-forming. We reshaped a Gaussian-like He-Ne laser beam into a beam with a more uniform intensity profile by a simple deformable mirror. (author)

Scanning Color Laser Microscope

Science.gov (United States)

Awamura, D.; Ode, T.; Yonezawa, M.

1988-01-01

A confocal color laser microscope which utilizes a three color laser light source (Red: He-Ne, Green: Ar, Blue: Ar) has been developed and is finding useful applications in the semiconductor field. The color laser microscope, when compared to a conventional microscope, offers superior color separation, higher resolution, and sharper contrast. Recently some new functions including a Focus Scan Memory, a Surface Profile Measurement System, a Critical Dimension Measurement system (CD) and an Optical Beam Induced Current Function (OBIC) have been developed for the color laser microscope. This paper will discuss these new features.

Analysis of monochromatic and quasi-monochromatic X-ray sources in imaging and therapy

Science.gov (United States)

Westphal, Maximillian; Lim, Sara; Nahar, Sultana; Orban, Christopher; Pradhan, Anil

2017-04-01

We studied biomedical imaging and therapeutic applications of recently developed quasi-monochromatic and monochromatic X-ray sources. Using the Monte Carlo code GEANT4, we found that the quasi-monochromatic 65 keV Gaussian X-ray spectrum created by inverse Compton scattering with relatavistic electron beams were capable of producing better image contrast with less radiation compared to conventional 120 kV broadband CT scans. We also explored possible experimental detection of theoretically predicted K α resonance fluorescence in high-Z elements using the European Synchrotron Research Facility with a tungsten (Z = 74) target. In addition, we studied a newly developed quasi-monochromatic source generated by converting broadband X-rays to monochromatic K α and β X-rays with a zirconium target (Z = 40). We will further study how these K α and K β dominated spectra can be implemented in conjunction with nanoparticles for targeted therapy. Acknowledgement: Ohio Supercomputer Center, Columbus, OH.

A Simple Laser Teaching Aid for Transverse Mode Structure Demonstration

Science.gov (United States)

Ren, Cheng; Zhang, Shulian

2009-01-01

A teaching aid for demonstrating the transverse mode structure in lasers is described. A novel device called "multi-dimension adjustable combined cat-eye reflector" has been constructed from easily available materials to form a He-Ne laser resonator. By finely adjusting the cat-eye, the boundary conditions of the laser cavity can be altered, which…

Optimal buffer gas pressure for laser-induced fluorescence detection of the iodine-129 isotope in the atmosphere

International Nuclear Information System (INIS)

Kireev, S.V.; Pit'ko, A.V.; Shnyrev, S.L.

1995-01-01

The effect of atmospheric air pressure on the intensity of iodine-129 vapor fluorescence excited by a He-Ne (633 nm) laser is studied. It is shown that to achieve the maximum intensity of fluorescence of molecular iodine-129, it is advantageous, first, to use a 3 He- 20 Ne laser for excitation, and second, to detect atmospheric iodine impurities in the gas mixture under analysis evacuated to 2 x 10 18 - 4 x 10 18 mol/cm 3 . In this case, the sensitivity increases about twofold. 7 refs., 4 figs

Digital frequency offset-locked He–Ne laser system with high beat frequency stability, narrow optical linewidth and optical fibre output

Science.gov (United States)

Sternkopf, Christian; Manske, Eberhard

2018-06-01

We report on the enhancement of a previously-presented heterodyne laser source on the basis of two phase-locked loop (PLL) frequency coupled internal-mirror He–Ne lasers. Our new system consists of two digitally controlled He–Ne lasers with slightly different wavelengths, and offers high-frequency stability and very narrow optical linewidth. The digitally controlled system has been realized by using a FPGA controller and transconductance amplifiers. The light of both lasers was coupled into separate fibres for heterodyne interferometer applications. To enhance the laser performance we observed the sensitivity of both laser tubes to electromagnetic noise from various laser power supplies and frequency control systems. Furthermore, we describe how the linewidth of a frequency-controlled He–Ne laser can be reduced during precise frequency stabilisation. The digitally controlled laser source reaches a standard beat frequency deviation of less than 20 Hz (with 1 s gate time) and a spectral full width at half maximum (FWHM) of the beat signal less than 3 kHz. The laser source has enough optical output power to serve a fibre-coupled multi axis heterodyne interferometer. The system can be adjusted to output beat frequencies in the range of 0.1 MHz–20 MHz.

Laser scanning camera inspects hazardous area

International Nuclear Information System (INIS)

Fryatt, A.; Miprode, C.

1985-01-01

Main operational characteristics of a new laser scanning camera are presented. The camera is intended primarily for low level high resolution viewing inside nuclear reactors. It uses a He-Ne laser beam raster; by detecting the reflected light by means of a phomultiplier, the subject under observation can be reconstructed in an electronic video store and reviewed on a conventional monitor screen

Questioning the observation of laser-assisted ionization in fast collisions of He(2 /sup 1,3/S) with He

International Nuclear Information System (INIS)

Gillen, K.T.

1989-01-01

In four recent papers Pradel et al. [Phys. Rev. Lett. 54, 2600 (1985); Phys. Rev. A 35, 1062 (1987)] and Monchicourt et al. [Phys. Rev. A 33, 3515 (1986); Chem. Phys. Lett. 152, 336 (1988)] give arguments claiming the observation of laser-assisted ionization of the short-lived collision complex formed during collisions of He/sup */(2 /sup 1,3/S) with He. However, estimates of the relative sizes of the assisted and unassisted ion signals observed make it very unlikely that laser-assisted ionization has been observed in those experiments. Collisional excitation to higher He/sup */ states, followed by (single-photon) ionization of the excited states, seems a more likely explanation at all energies considered

Application of laser therapy in treating inherited forms of psychoverbal retardation in children

Science.gov (United States)

Ulas, V. Y.; Voinova, V. M.; Il'in, L. B.; Troitskaya, L. A.; Dobrynina, E. V.; Kazantseva, L. Z.

2001-04-01

An investigation was made of applying combined laser therapy in the treatment of 619 children (422 children constituted the experimental group and 197 children composed the control group) affected by inherited forms of psychoverbal retardation. It was found that low-intensity He-Ne laser radiation with the wavelength of 632.8 nm and the output power of 2 mW made it possible to improve the children's mental development. Moreover, it effectively increased their mental activities, such as speech, communication, arbitrary behavior regulation, and locomotory functions. Laser therapy applied in treating children affected by the arrested mental development aggravated by obesity additionally decreased their body weight, increased their field of vision, and eliminated dyslipidemia. It was also found that contraindications to He-Ne laser acupuncture included phenylketonuria-related noncorrected metabolic defects, convulsive syndromes, epileptic activities, convulsive readiness, and cerebrolysine intramuscular injections.

Production of highly polarized 3He using spectrally narrowed diode laser array bars

International Nuclear Information System (INIS)

Chann, B.; Babcock, E.; Anderson, L.W.; Walker, T.G.; Chen, W.C.; Smith, T.B.; Thompson, A.K.; Gentile, T.R.

2003-01-01

We have produced 70%-75% 3 He polarization by spin-exchange optical pumping in cells ≅100 cm 3 in volume. The polarization achieved is consistent with known spin-exchange and spin-relaxation rates, but only when the recently discovered temperature dependence of 3 He relaxation is included. Absolute 3 He polarization measurements were performed using two different methods in two different laboratories. The results were obtained with either a spectrally narrowed laser or one type of broadband laser. Based on tests of several larger cells at pressures near 1 bar, we find that the power required to reach the same polarization is typically three times lower for the spectrally narrowed laser. This last result indicates that spectrally narrowed lasers will be important for obtaining the highest polarization in large volume neutron spin filters. Polarization in excess of 55% as obtained in cells up to 640 cm 3 in volume and 70% polarization is anticipated with available increases in spectrally narrowed laser power

Modeling of Output Characteristics of a UV Cu+ Ne-CuBr Laser

Directory of Open Access Journals (Sweden)

Snezhana Georgieva Gocheva-Ilieva

2012-01-01

Full Text Available This paper examines experiment data for a Ne-CuBr UV copper ion laser excited by longitudinal pulsed discharge emitting in multiline regime. The flexible multivariate adaptive regression splines (MARSs method has been used to develop nonparametric regression models describing the laser output power and service life of the devices. The models have been constructed as explicit functions of 9 basic input laser characteristics. The obtained models account for local nonlinearities of the relationships within the various multivariate subregions. The built best MARS models account for over 98% of data. The models are used to estimate the investigated output laser characteristics of existing UV lasers. The capabilities for using the models in predicting existing and future experiments have been demonstrated. Specific analyses have been presented comparing the models with actual experiments. The obtained results are applicable for guiding and planning the engineering experiment. The modeling methodology can be applied for a wide range of similar lasers and laser devices.

Application of nuclear pumped laser to an optical self-powered neutron detector

Science.gov (United States)

Yamanaka, N.; Takahashi, H.; Iguchi, T.; Nakazawa, M.; Kakuta, T.; Yamagishi, H.; Katagiri, M.

1996-05-01

A Nuclear Pumped Laser (NPL) using 3He/Ne/Ar gas mixture is investigated for a purpose of applying to an optical self-powered neutron detector. Reactor experiments and simulations on lasing mechanism have been made to estimate the best gas pressure and mixture ratios on the threshold input power density (or thermal neutron flux) in 3He/Ne/Ar mixture. Calculational results show that the best mixture pressure is 3He/Ne/Ar=2280/60/100 Torr and thermal neutron flux threshold 5×1012 n/cm2 sec, while the reactor experiments made in the research reactor ``YAYOI'' of the University of Tokyo and ``JRR-4'' of JAERI also demonstrate that excitational efficiency is maximized in a similar gas mixture predicted by the calculation.

Studies on laser-assisted Penning ionization by the optogalvanic effect in Ne/Eu hollow cathode discharge.

Science.gov (United States)

Saini, V K; Kumar, P; Dixit, S K; Nakhe, S V

2015-02-01

Laser-assisted Penning ionization (LAPI) is detected in a Ne/Eu hollow cathode (HC) discharge lamp using the pulsed optogalvanic (OG) method. In the Ne/Eu discharge, doubly ionized europium excited energy levels Eu[4f(7)(P(7/2,5/2)6)] lie within the thermal limit (∼kT) from the laser-excited neon's energy level [2p(5)(P3/202)3p or 2p(8) (in Paschen notation)] lying at 149,848  cm(-1). Therefore, Penning ionization (PI) of europium atoms likely to occur into its highly excited ionic states is investigated. To probe the PI of europium, the temporal profiles of its counterpart neon OG signal are studied as a function of discharge current for the transitions (1s(4)→2p(8)) and (1s(2)→2p(2)), corresponding to 650.65 and 659.89 nm wavelengths, respectively. It is observed that PI of europium alters the overall discharge characteristics significantly and, hence, modifies the temporal profile of the OG signals accordingly. The quasi-resonant ionizing energy transfer collisions between laser-excited Ne 2p(8) atoms and electronically excited europium P(9/2)10 atoms are used to explain the LAPI mechanism. Such LAPI studies carried out in HC discharge could be useful for the discharge of a metal-vapor laser with appropriate Penning mixtures.

Laser-induced fluorescence spectra of Ba+*-He exciplexes produced in cold He gas

International Nuclear Information System (INIS)

Fukuyama, Yoshimitsu; Matsuo, Yukari; Moriwaki, Yoshiki

2004-01-01

We report the observation of laser-induced fluorescence spectra of Ba +* -He exciplexes. The experiment is carried out in an environment of cold gaseous helium at a temperature range of 3-30 K. We have observed the emission spectra of exciplexes by means of excitation of the 6p 2 P 32 2 S 12 transition of Ba + ions. It is found that these spectra are redshifted from the D2 emission line in the free space and are composed of several peaks. The experimental results are reproduced well by theoretical calculation of the emission spectra for vibrational levels of Ba +* -He. We also investigate the vibrational dynamics of the 6p 2 Π 32 state of Ba + *-He, and we have determined the collision-induced vibrational relaxation cross sections of the 6p 2 Π 32 state to be 9.7±1.1 A 2 at 15 K

Discharge-current characteristics in UV-preionized Kr/He, F2/He gas-mixtures and KrF excimer laser gas. Shigaisen yobi denri Kr/He, F2/He kongo kitai hoden oyobi KrF laser reiki hoden no denryu tokusei

Energy Technology Data Exchange (ETDEWEB)

Nakagawa, N.; Kawakami, H.; Yukimura, K. (Doshisha University, Kyoto (Japan))

1992-08-15

In order to study effects of Kr and F2 on discharge characteristics of KrF excimer laser gas, gap phenomena in Kr/He and F2/He gas-mixtures were observed and discharge current (I[sub d]) was measured. In the range where Kr concentration was over 10% in Kr/He gas, in which production of filamentation as well as glow discharge started, discontinuous change in I[sub d] in the second or third half cycle was observed. According to the results of experiments and model analyses, it was considered that the discontinuity of the current showed the transition point to filamentation. When F2 concentration was in the range between 0.1 and 0.3% in F2/He mixture gas, filamentation and arc with glow were observed. Sine-waveform I[sub d] ended in the first half cycle, and began to flow again after cessation or had almost constant current due to arc and others. When F2 was over 0.4%, only are discharge was observed. It was thus found that F2 has a large effect on discharge characteristics of KrF laser gas. 18 refs., 9 figs.

Comment on 'Experimental study of single- and double-electron transfer in slow Ne8++He collisions using photon and electron spectroscopy'

International Nuclear Information System (INIS)

Bordenave-Montesquieu, A.; Moretto-Capelle, P.; Bordenave-Montesquieu, D.

2002-01-01

In this Comment we question the recent emphasis by Langereis et al. [Phys. Rev. A 60, 2917 (1999)] that excitation of triplet states in double-capture processes is noticeable in the Ne 8+ (1s 2 ) 1 S+He(1s 2 ) 1 S collisional system at 80 keV. We demonstrate that all their identified Ne 6+ (1s 2 3lnl ' ) autoionizing transitions can be perfectly explained by excitation of singlet states alone. In our opinion their findings based on electron spectroscopy rely on too inaccurate spectrum analysis and theoretical input data

Gap In A Laser Frequency He-Ne at 632.8 nm | Aissani | Journal of ...

African Journals Online (AJOL)

The aim of this work is to show that the emitted signals of a double-output laser cavity exhibit distinctive features, manifesting themselves through typical dissymmetry in the corresponding spectral line shapes. Usually, such a dissymmetry in an inhomogeneously broadened gas laser appears with a clear but unpredictable ...

Collision velocity dependence of double capture processes in N7+ and Ne8+ + He systems (v = 0.18 to 0.61 au)

International Nuclear Information System (INIS)

Moretto-Capelle, P.; Benoit-Cattin, P.; Bordenave-Montesquieu, A.; Gleizes, A.

1991-01-01

Double capture processes depend on the collision velocity in the complicated way which is different for N 7+ and Ne 8+ + He collisional systems. Some examples of energy dependence for differential and total cross sections are given. (orig.)

Optimum discharge current waveforms for pumping Ne-like Ar soft X-ray laser

International Nuclear Information System (INIS)

Zhao Yongpeng; Jiang Shan; Xie Yao; Teng Shupeng; Wang Qi

2011-01-01

In order to enhance intensity of Ne-like Ar 46.9 nm soft X-ray laser pumped by capillary discharge, influences of main current waveform on Z-pinch process,time of lasing onset and laser intensity were studied. Rise-time of main current waveform was changed by varying conducting inductance of main switch. Experimental results with different rise-times show that amplitude of laser spike decreases with increasing rise-time,and time of lasing onset increases with increasing rise-time. In addition, influences of average current changing rate on laser intensity were studied. When inner diameter of capillary is 3 mm and initial pressure is 30 Pa, optimum average current changing rate is about 7.0 x 10 11 A/s. (authors)

Principle tests of reactor pumped laser of 3He-Ar-Xe system

International Nuclear Information System (INIS)

Chen Hande; Jin Xingxing; Yang Chengde

1994-01-01

A nuclear reactor-pumped laser was demonstrated firstly by using the 3 He(P,n) 3 H reaction to excite a 3 He-Ar-Xe laser. Lasing was observed on the 1.73 μm (5d (3/2) 1 -6p(5/2) 1 transition) in Xe I. The CAEP Pulsed Reactor (CFBR-II) was used as a source of fast neutrons moderated by a 50 mm thick polyethylene sleeve around the laser cell. A laser cell was constructed from K 9 glass tubing 600 mm long and Φ34 mm with each end cut at Brewster's angle (quartz). The laser cell was baked out to 10 -3 Pa prior to filling with research-grade mixture ( 3 He/Ar/Xe = 34.7: 34.7: 0.267 kPa). A dielectric-coated 2 m radius-curvature back mirror (99.7% reflectivity at 1.73 μm) and a flat output coupler (Φ30 mm) were used to form the optical cavity. The cavity optics were placed outside the cell as shown in Fig.3. A schematic of the experimental configuration is shown. Typical laser signals obtained with the Ge detector (-80 degree C) are also shown. Laser output lags the fast neutron pulse by the neutron thermalization time (∼278 μs). The observed light output was shown to be caused by stimulated emission, because the signal disappeared when the reflecting (flat) mirror was covered. This precludes the possibility that the phenomenon was the result of γ-radiation interaction with the detector or the air in the light path. The measured laser energy was 80 times the maximum possible fluorescence energy. The observed wavelength was measured to be 1.73 μm by using glass filters. Laser output duration was approximately 735 μs

The detection of He in tungsten following ion implantation by laser-induced breakdown spectroscopy

Science.gov (United States)

Shaw, G.; Bannister, M.; Biewer, T. M.; Martin, M. Z.; Meyer, F.; Wirth, B. D.

2018-01-01

Laser-induced breakdown spectroscopy (LIBS) results are presented that provide depth-resolved identification of He implanted in polycrystalline tungsten (PC-W) targets by a 200 keV He+ ion beam, with a surface temperature of approximately 900 °C and a peak fluence of 1023 m-2. He retention, and the influence of He on deuterium and tritium recycling, permeation, and retention in PC-W plasma facing components are important questions for the divertor and plasma facing components in a fusion reactor, yet are difficult to quantify. The purpose of this work is to demonstrate the ability of LIBS to identify helium in tungsten; to investigate the sensitivity of laser parameters including, laser energy and gate delay, that directly influence the sensitivity and depth resolution of LIBS; and to perform a proof-of-principle experiment using LIBS to measure relative He intensities as a function of depth. The results presented demonstrate the potential not only to identify helium but also to develop a methodology to quantify gaseous impurity concentration in PC-W as a function of depth.

CW-laser induced microchannels in dye-polymethacrylic acid films

OpenAIRE

M.A. Camacho-López

2007-01-01

In this work we report on the formation of microchannels on dye-polymethacrylic acid films using a cw-laser. A focalized beam of a He-Ne laser (632.8 nm emission line) was used to form microchannels on the films. It was found that there exists a laser power density threshold for a pit formation that depends on the dye concentration. The dimensions of the laser-induced channels are dependent on the laser power density. Microchannel formation in the transparent polymethacrylic acid films was no...

Observation of a laser-assisted ionization of the He(21S,23S)+He(11S) collision system involving a bound-free transition

International Nuclear Information System (INIS)

Pradel, P.; Monchicourt, P.; Dubreuil, D.; Heuze, J.; Laucagne, J.J.; Spiess, G.

1985-01-01

We report the first observation of an assisted He + yield arising from single collisions between a He(2 1 S,2 3 S) atom beam on a He(1 1 S) target in the presence of an intense laser field. A time-of-flight analysis shows that the pulsed laser-assisted ion signal is reproducible, energy dependent, and appears in addition to the continuous ion flux coming from a known field-free diabatic channel. From the estimated value of the diabatic ionization cross section sigma/sub d/, the order of magnitude of the assisted-ionization cross section sigma/sub a/ is given

Broadening of some He I and He II lines in a plasma

International Nuclear Information System (INIS)

Einfeld, D.; Sauerbrey, G.

1975-01-01

The broadening of the He I and He II lines was investigated in a wall-stabilized discharge (duration approximately 500 μs, Ne approximately 2 x 10 16 cm -3 , T approximately 37,000 K). The xi factor calculated by Kriener and Schlueter could be used for the Ne determination from the continuum radiation. For the line width of the He I line 501.4 nm, the discrepancy of a factor 1.7 to Griem, Baranger, Kolb, Oertel reported by Kusch was confirmed. Also confirmed was the theoretical dependence of the distance between the group peaks on the electron densities for the He I lines 447.1 nm and 492.1 nm, first reported by Griem and Barnard et al. The line widths of the He II lines 320.3 nm and 408.6 nm are between the values given by Kepple and Griem, and Griem, Kolb, Shen. (orig./AK) [de

Nonsequential multiphoton double ionization of He in intense laser - a QED approach

International Nuclear Information System (INIS)

Bhattacharyya, S.; Mazumder, Mina; Chakrabarti, J.; Faisal, F.H.M.

2010-01-01

The non-sequential muItiphoton double ionization (NSDI) of He in intense laser field is not yet completely understood, more so for spin resolved currents. We are tempted to use QED and Feynman diagram to obtain spin polarized currents. Hartree-Fock (HF) ground-state correlated wave function of He atom is considered in circularly polarized laser. In QED approach one of the electrons is directly ionized by photon absorption while the second electron is shaken off due to the change in the internal potential of the atom. In He-atom the two ionized electrons can only be in the singlet spin state. Spin-symmetric and spin-flip transitions are eventually possible for the direct and the shake-off electrons. In an ensemble of (HF type) He-atoms the ionized Volkov electrons may acquire 4 pairs of momenta indicating e-e correlation in the final state. Coulomb correction is taken care off through the Sommerfeld factor

Geothermal He and CO2 variations at Changbaishan intra-plate volcano (NE China) and the nature of the sub-continental lithospheric mantle

Science.gov (United States)

Hahm, D.; Hilton, D. R.; Cho, M.; Wei, H.; Kim, K.-R.

2008-11-01

We report new He and CO2 data for geothermal fluids from Changbaishan Volcano located on the border of China and North Korea. Helium isotope ratios reach a maximum of 5.4 RA (where RA = 3He/4He in air) whereas carbon isotope values (δ 13C) fall between -2 and -7 ‰ (vs. PDB). The ratio of CO2/3He varies between 0.5-7.1 (×109) for gas samples but is considerably higher (~1012) in waters. The combined He-CO2 systematics reveal the clear imprint of a dominant subducted slab contribution to the total CO2 inventory. We conclude that these geothermal volatiles originate from the sub-continental lithospheric mantle (SCLM) in NE China and represent ancient fluids captured by prior metasomatic events.

Anisotropic optical feedback of single frequency intra-cavity He–Ne laser

International Nuclear Information System (INIS)

Lu-Fei, Zhou; Shu-Lian, Zhang; Yi-Dong, Tan; Wei-Xin, Liu; Bin, Zhang

2009-01-01

This paper presents the anisotropic optical feedback of a single frequency intra-cavity He–Ne laser. A novel phenomenon was discovered that the laser output an elliptical polarized frequency instead of the initial linear polarized one. Two intensities with a phase difference were detected, both of which were modulated in the form of cosine wave and a fringe shift corresponds to a λ/2 movement of the feedback mirror. The phase difference can be continuously modulated by the wave plate in the external cavity. Frequency stabilization was used to stabilize the laser frequency so as to enlarge the measuring range and improve the measurement precision. This anisotropic optical feedback system offers a potential displacement measurement technology with the function of subdivision of λ/2 and in-time direction judgment. The three-mirror Fabry–Perot cavity model is used to present the experimental results. Given the lack of need of lasing adjustment, this full intra-cavity laser can significantly improve the simplicity and stability of the optical feedback system. (fluids, plasmas and electric discharges)

Feasibility of laser pumping with neutron fluxes from present-day large tokamaks

Energy Technology Data Exchange (ETDEWEB)

Jassby, D.L.

1986-08-01

The minimum fusion-neutron flux needed to observe nuclear-pumped lasing with tokamaks can be reduced substantially by optimizing neutron scattering into the laser cell, located between adjacent toroidal-field coils. The laser lines most readily pumped are probably the /sup 3/He-Ne lines at 0.633 ..mu.. and in the infrared, where the /sup 3/He-Ne gas is excited by energetic ions produced in the /sup 3/He(n,p)T reaction. These lines are expected to lase at the levels of D-T neutron flux foreseen for the TFTR in 1989 (>>10/sup 12/ n/cm/sup 2//s), while amplification should be observable at the existing levels of D-D neutron flux (greater than or equal to 5 x 10/sup 9/ n/cm/sup 2//s). Lasing on the 1.73 ..mu.. and 2.63 ..mu.. transitions of Xe may be observable at the maximum expected levels of D-T neutron flux in TFTR enhanced by scattering.

Feasibility of laser pumping with neutron fluxes from present-day large tokamaks

International Nuclear Information System (INIS)

Jassby, D.L.

1986-08-01

The minimum fusion-neutron flux needed to observe nuclear-pumped lasing with tokamaks can be reduced substantially by optimizing neutron scattering into the laser cell, located between adjacent toroidal-field coils. The laser lines most readily pumped are probably the 3 He-Ne lines at 0.633 μ and in the infrared, where the 3 He-Ne gas is excited by energetic ions produced in the 3 He(n,p)T reaction. These lines are expected to lase at the levels of D-T neutron flux foreseen for the TFTR in 1989 (>>10 12 n/cm 2 /s), while amplification should be observable at the existing levels of D-D neutron flux (≥ 5 x 10 9 n/cm 2 /s). Lasing on the 1.73 μ and 2.63 μ transitions of Xe may be observable at the maximum expected levels of D-T neutron flux in TFTR enhanced by scattering

Imaging the He2 quantum halo state using a free electron laser

Science.gov (United States)

Zeller, Stefan; Kunitski, Maksim; Voigtsberger, Jörg; Kalinin, Anton; Schottelius, Alexander; Schober, Carl; Waitz, Markus; Sann, Hendrik; Hartung, Alexander; Bauer, Tobias; Pitzer, Martin; Trinter, Florian; Goihl, Christoph; Janke, Christian; Richter, Martin; Kastirke, Gregor; Weller, Miriam; Czasch, Achim; Kitzler, Markus; Braune, Markus; Grisenti, Robert E.; Schöllkopf, Wieland; Schmidt, Lothar Ph. H.; Schöffler, Markus S.; Williams, Joshua B.; Jahnke, Till; Dörner, Reinhard

2016-12-01

Quantum tunneling is a ubiquitous phenomenon in nature and crucial for many technological applications. It allows quantum particles to reach regions in space which are energetically not accessible according to classical mechanics. In this “tunneling region,” the particle density is known to decay exponentially. This behavior is universal across all energy scales from nuclear physics to chemistry and solid state systems. Although typically only a small fraction of a particle wavefunction extends into the tunneling region, we present here an extreme quantum system: a gigantic molecule consisting of two helium atoms, with an 80% probability that its two nuclei will be found in this classical forbidden region. This circumstance allows us to directly image the exponentially decaying density of a tunneling particle, which we achieved for over two orders of magnitude. Imaging a tunneling particle shows one of the few features of our world that is truly universal: the probability to find one of the constituents of bound matter far away is never zero but decreases exponentially. The results were obtained by Coulomb explosion imaging using a free electron laser and furthermore yielded He2’s binding energy of 151.9±13.3151.9±13.3 neV, which is in agreement with most recent calculations.

Semiconductor lasers in rheumatological treatment

Science.gov (United States)

Pascu, Mihail-Lucian; Suteanu, S.; Ignat, P.; Pruna, Simion; Chitu, A.

1995-03-01

A computer controlled equipment, containing 6 lasers (HeNe and 5 diode lasers--DL) conceived to be used in rheumatological treatment is reported. DL emit at 895 nm and for typical applications, their expanded spots are superposed within the irradiation plane, on the HeNE defocused spot used to define the surface to be irradiated. DL emit 100 nsec pulses between 0.5 KHz and 1.5 KHz repetition rate and 0.5 mW average power (measured at 1 KHz). 150 patients with rheumathologic diseases were treated: lumbar spondylosis (75), gonarthrosis (30), cervical spondylosis (21), coxarthrosis (15), Heberden and Bouchard (9). The treatment consisted of: group I, 50 patients--laser therapy, 10 min/day, 10 days; group II, 50 patients--classical antirheumatic treatment; group III, 50 patients--mixed treatment. Assessment of sympathetic skin activity made using reactometry measurements, shows that latency time was longer before irradiation, 1867 +/- 289) msec then after, (1234 +/- 321) msec. Pain rating indexes decreasing for all three groups of patients were measured. Better results for more superficial diseases were obtained and best results were observed after irradiation with 1 KHz - 1.5 KHz repetition rate IR pulses. Better results were obtained when spot irradiation in a few points combined with zone irradiations was used.

Effect Of Laser Irradiation On Biosynthesis Of Antibiotics

International Nuclear Information System (INIS)

SALAMA, S.M.; MAHMOUD, S.M.; EL-KABBANY, H.M.

2010-01-01

An investigation concerning the effect of He:Ne laser irradiation on some isolated actinomycetes was carried out. Seven isolated actinomycetes were considered as most potent producing broad spectrum antibiotics. The strains have been identified on the basis of taxonomic studies as Streptomyces nogalator (H12), Streptomyces griseoluteus (YM23), Amycolatopsis mediterranei (B40), Glycomyces harbinensis (KA16), Streptosporangium corrugatum (B67), Streptoalloteichus hindustamus (B74) and Streptomyces aurantiogriseus (S15). Seven genotypes were chosen after He:Ne laser irradiation as representative for each isolated strain. The active metabolite from most potent genotype of Streptomyces nogalator (H12) was extracted by ethyl acetate then concentrated under vacuo and the crude fraction was purified using thin layer and column chromatography. Ultra violet maximum absorption peak was recorded at 231.5 and 206 nm. The IR and NMR were consulted to confirm the chemical characteristics of the antibiotic. The biological activity and toxicity were also investigated.

Application of ring lasers to determine the directions to the poles of Earth's rotation

International Nuclear Information System (INIS)

Golyaev, Yu D; Kolbas, Yu Yu

2012-01-01

Application of a ring laser to determine the directions to the poles of Earth's rotation is considered. The maximum accuracy of determining the directions is calculated, physical and technical mechanisms that limit the accuracy are analysed, and the instrumental errors are estimated by the example of ring He — Ne lasers with Zeeman biasing. (laser applications and other topics in quantum electronics)

Frequency stabilized HeNe gas laser with 3.5 mW from a single mode

NARCIS (Netherlands)

Ellis, J.D.; Voigt, D.; Spronck, J.W.; Verlaan, A.L.; Munnig Schmidt, R.H.

2012-01-01

This paper describes an optical frequency stabilization technique using a three-mode Helium Neon laser at 632.8 nm. Using this configuration, a maximum frequency stability relative to an iodine stabilized laser of 6×10 -12 (71 s integration time) was achieved. Two long term measurements of 62 h and

Solar cycle variation of interstellar neutral He, Ne, O density and pick-up ions along the Earth's orbit

OpenAIRE

Sokół, Justyna M.; Bzowski, Maciej; Kubiak, Marzena A.; Möbius, Eberhard

2016-01-01

We simulated the modulation of the interstellar neutral (ISN) He, Ne, and O density and pick-up ion (PUI) production rate and count rate along the Earth's orbit over the solar cycle from 2002 to 2013 to verify if solar cycle-related effects may modify the inferred ecliptic longitude of the ISN inflow direction. We adopted the classical PUI model with isotropic distribution function and adiabatic cooling, modified by time- and heliolatitude-dependent ionization rates and non-zero injection spe...

Anomalous intensities of Ne-like ion resonance line in plasma produced by picosecond laser pulse

International Nuclear Information System (INIS)

Bryunetkin, B.A.; Skobelev, I.Yu.; Faenov, A.Ya.; Kalashnikov, M.P.; Nikles, P.; Shnyupep, M.

1995-01-01

An anomalous structure of intensities of spectral lines of CuXX and GeXXX Ne-like ions emitted by plasma produced by laser pulses of picosecond duration and up to 2x10 18 W/cm 2 flux density is recorded for the first time. It is shown that spectrum maximum of these ions is emitted from a plasma region whose density is significantly above the critical value of the length of heating laser radiation wave. 9 refs.; 3 figs

Cosmogenic He and Ne in chondrules from clastic matrix and a lithic clast of Murchison : No pre-irradiation by the early sun

NARCIS (Netherlands)

Riebe, My E.I.; Huber, Liliane; Metzler, Knut; Busemann, Henner; Luginbuehl, Stefanie M.; Meier, Matthias M.M.; Maden, Colin; Wieler, Rainer

2017-01-01

Whether or not some meteorites retain a record of irradiation by a large flux of energetic particles from the early sun in the form of excesses of cosmic-ray produced noble gases in individual crystals or single chondrules is a topic of ongoing debate. Here, we present He and Ne isotopic data for

Laser experimental system as teaching aid for demonstrating basic phenomena of laser feedback

International Nuclear Information System (INIS)

Xu, Ling; Zhao, Shijie; Zhang, Shulian

2015-01-01

An experimental laser teaching system is developed to demonstrate laser feedback phenomena, which bring great harm to optical communication and benefits to precision measurement. The system consists of an orthogonally polarized He-Ne laser, a feedback mirror which reflects the laser output light into the laser cavity, and an optical attenuator which changes the intensity of the feedback light. As the feedback mirror is driven by a piezoelectric ceramic, the attenuator is adjusted and the feedback mirror is tilted, the system can demonstrate many basic laser feedback phenomena, including weak, moderate and strong optical feedback, multiple feedback and polarization flipping. Demonstrations of these phenomena can give students a better understanding about the intensity and polarization of lasers. The system is well designed and assembled, simple to operate, and provides a valuable teaching aid at an undergraduate level. (paper)

A 223-nm KrCl excimer laser on a He-Kr-HCl mixture

International Nuclear Information System (INIS)

Razhev, A M; Zhupikov, A A; Kargapol'tsev, E S

2004-01-01

The results of experimental studies of the parameters of a 223-nm electric-discharge KrCl excimer laser on a He-Kr-HCl mixture depending on the excitation conditions and the composition of the active gaseous medium are presented. To achieve the maximum values of the output energy and the efficiency of the KrCl laser on mixtures with buffer gaseous helium, an excitation system was used that included a circuit with an LC inverter with a high-voltage switch based on an RU-65 spark gap. An output energy of 320 mJ with an efficiency of 0.5% relative to the energy stored in the capacitors is obtained in a KrCl laser with an active medium based on the buffer He gas at a charging voltage of 30 kV. Radiation pulses with a duration of 22±1 ns and a pulse power of 15 MW are obtained. (lasers)

Momentum distributions of selected rare-gas atoms probed by intense femtosecond laser pulses

DEFF Research Database (Denmark)

Abu-Samha, Mahmoud; Madsen, Lars Bojer

2011-01-01

We provide a direct comparison between numerical and experimental (Rudenko et al 2004 J. Phys. B: At. Mol. Opt. Phys. 37 L407) photoelectron momentum distributions in strong-field ionization of selected rare-gas atoms (He, Ne and Ar), probed by femtosecond linearly polarized laser pulses. The cal......We provide a direct comparison between numerical and experimental (Rudenko et al 2004 J. Phys. B: At. Mol. Opt. Phys. 37 L407) photoelectron momentum distributions in strong-field ionization of selected rare-gas atoms (He, Ne and Ar), probed by femtosecond linearly polarized laser pulses....... The calculations are performed by solving the time-dependent Schrödinger equation within the single-active-electron approximation, and focal-volume effects are taken into account by appropriately averaging the results. The resulting momentum distributions are in quantitative agreement with the experimental...

Boltzmann equation analysis of electrons swarm parameters and properties of excited particle number densities in Xe/Ne plasmas. Laser absorption effect; Xe/Ne plasma chudenshi yuso keisu narabi ni reiki ryushisu mitsudo tokusei no Boltzmann hoteishiki kaiseki. Laser ko kyushu koka

Energy Technology Data Exchange (ETDEWEB)

Uchida, S.; Sugawara, H.; Ventzek, P.; Sakai, Y. [Hokkaido University, Sapporo (Japan)

1998-06-01

Xe/Ne plasmas are important for plasma display panels and VUV light sources. However, reactions between electrons and excited particles in the mixtures are so complicated that influence of the reactions on the plasma properties is not understood well. In this work, taking account of reactions through which electrons are produced, such as cumulative and Penning ionization, and of transition between excited levels, the electron and excited particle properties in Xe/Ne plasmas are calculated using the Boltzmann equation. The ionization coefficient and electron drift velocity agreed with experimental data. The influence of laser absorption in Xe/Ne plasmas on the plasma properties is also discussed. 25 refs., 15 figs.

Low power laser irradiation does not affect the generation of signals in a sensory receptor

Energy Technology Data Exchange (ETDEWEB)

Lundeberg, T.; Zhou, J.

1989-01-01

The effect of low power Helium-Neon (He-Ne) and Gallium-Arsenide (Ga-As) laser on the slowly adapting crustacean stretch receptor was studied. The results showed that low power laser irradiation did not affect the membrane potential of the stretch receptor. These results are discussed in relation to the use of low power laser irradiation on the skin overlaying acupuncture points in treatment of pain syndrome.

Trace gas detection by laser intracavity photothermal spectroscopy

International Nuclear Information System (INIS)

Fung, K.H.; Lin, H.h.

1986-01-01

A novel laser intracavity photothermal detector is described. In this scheme, sample absorption of the pump laser power takes place within the cavity of a probe He-Ne laser causing modulation in the gain and in turn the output power. Comparison of this intracavity detector with two other photothermal techniques, namely, phase fluctuation optical heterodyne spectroscopy and thermal beam deflection, is made in terms of practicality and sensitivity. For in situ measurements, sensitivity of 0.5 x 10 -7 cm -1 for a probe length of 3 cm has been achieved

Laser Photochemistry.

Science.gov (United States)

1981-07-01

inverted by the first, i.e., at the moment of time t = T, such that i = (2n+)lT, where 0 is the Rabi frequency (Oraevski et al., 1976). . classical... anisotropic molecule present. CW HeNe, Ar+ and Kr+ lasers are used, and the filter method is necessary because of time-scales lo8 - 10ll Hz. Some general...e.g., truncated harmonic oscillator, square well, spherically symmetric Morse or Lennard-Jones, anisotropic (angle-dependent) Morse or Lennard-Jones

0 degree binary encounter electron production in 30-MeV Oq++H2, He, O2, Ne, and Ar collisions

International Nuclear Information System (INIS)

Zouros, T.J.; Wong, K.L.; Grabbe, S.; Hidmi, H.I.; Richard, P.; Montenegro, E.C.; Sanders, J.M.; Liao, C.; Hagmann, S.; Bhalla, C.P.

1996-01-01

Double-differential cross sections (DDCS close-quote s) for the production of binary encounter electrons (BEE close-quote s) were measured for collisions of 30-MeV O q+ projectiles with H 2 , He, O 2 , Ne, and Ar targets with q=4 endash 8 and an electron ejection angle of θ=0 degree with respect to the beam direction. Particular interest focused on (a) the evaluation of the contributions of the different electron subshells of the multielectron targets, O 2 , Ne, and Ar; (b) the study of the well-known enhancement of the BEE DDCS close-quote s with decreasing projectile charge-state q; here this dependence was tested for higher collision energies and new targets; (c) the study of the dependence of the BEE peak energy on the particular target and projectile charge state. Results were analyzed in terms of the impulse approximation, in which target electrons in the projectile frame undergo 180 degree elastic scattering in the field of the projectile ion. The electron scattering calculations were performed in a partial-wave treatment using the Hartree-Fock model. Good agreement with the data was found for the H 2 and He targets, while for the multielectron targets O 2 , Ne, and Ar only electrons whose velocity was lower than the projectile velocity needed to be included for good agreement. All measured BEE DDCS close-quote s were found to increase with decreasing projectile charge state, in agreement with other recent BEE results. The BEE peak energies were found to be independent of the projectile charge state for all targets utilized. copyright 1996 The American Physical Society

Evaluation of the role of laser bio stimulation on skin and liver of gamma-irradiated mice

International Nuclear Information System (INIS)

Salem, E.S.

2007-01-01

Low level laser therapy (LLLT) is used in different medical fields due to its therapeutic effects on reparative processes, pain relief and bio stimulation (Castro-e-silva et al., 2003). The present study aimed at evaluating the therapeutic efficacy of He-Ne laser in stimulating the reparative processes after whole body irradiation of mice using a sublethal dose (5 Gy) of gamma rays. Two vital organs were studied, a radio-sensitive one (the skin) as well as a relatively radio-resistant one (the liver) . During the course of the present work, some biochemical parameters as well as histopathological changes in the skin and liver tissues induced by whole body gamma ionizing radiation were studied. Female mice (240) were used and divided into 6 groups and laser therapy was carried out using a computerized scanner emitting He-Ne(C W) with a wavelength of 632.8 nm and the fluence was 5 j/cm 2 . Experimental investigation have been carried out along two main lines: Biochemical investigations for the assessment of serum transferases and histopathological assessment of liver and skin biopsy.On the basis of the current results it could be concluded that mice exposed to whole body gamma irradiation either by the US of the shot or the fractionated sublethal dose suffered an aggravated histopathological changes in the skin and liver tissues which were associated with certain biochemical disturbances of the liver function testes. These undesirable alterations were ameliorated by the early treatment of mice by He -Ne laser immediately post exposure before being irreversibly damaged

Time-dependent H-like and He-like Al lines produced by ultra-short pulse laser

Energy Technology Data Exchange (ETDEWEB)

Kato, Takako; Kato, Masatoshi [National Inst. for Fusion Science, Nagoya (Japan); Shepherd, R; Young, B; More, R; Osterheld, Al

1998-03-01

We have performed numerical modeling of time-resolved x-ray spectra from thin foil targets heated by the LLNL Ultra-short pulse (USP) laser. The targets were aluminum foils of thickness ranging from 250 A to 1250 A, heated with 120 fsec pulses of 400 nm light from the USP laser. The laser energy was approximately 0.2 Joules, focused to a 3 micron spot size for a peak intensity near 2 x 10{sup 19} W/cm{sup 2}. Ly{alpha} and He{alpha} lines were recorded using a 900 fsec x-ray streak camera. We calculate the effective ionization, recombination and emission rate coefficients including density effects for H-like and He-like aluminum ions using a collisional radiative model. We calculate time-dependent ion abundances using these effective ionization and recombination rate coefficients. The time-dependent electron temperature and density used in the calculation are based on an analytical model for the hydrodynamic expansion of the target foils. During the laser pulse the target is ionized. After the laser heating stops, the plasma begins to recombine. Using the calculated time dependent ion abundances and the effective emission rate coefficients, we calculate the time dependent Ly{alpha} and He{alpha} lines. The calculations reproduce the main qualitative features of the experimental spectra. (author)

Only lasers can be used for low level laser therapy.

Science.gov (United States)

Moskvin, Sergey Vladimirovich

2017-12-01

The question of lasers' exclusivity, as well as the degree of influence of special properties of low-intensity laser illumination (LILI), such as coherence, polarity and monochromaticity, on the effectiveness of low level laser therapy (LLLT) continues to cause arguments. The study analyzes publications from 1973 to 2016, in which laser and conventional light sources are compared, and the following conclusions are drawn. First, there are a lot of publications with incorrect comparison or unfounded statements. Secondly, other sources of light are often meant by LILI without any justification. Thirdly, all studies, in which the comparison is carried out correctly and close parameters of the impact and the model are used, have a firm conclusion that laser light is much more effective. Fourthly, it is uniquely identified that the most important parameter that determines the efficiency of lasers is monochromaticity, i.e., a much narrower spectral width than for all other light sources. Only laser light sources can be used for LLLT! © Author(s) 2017. This article is published with open access by China Medical University.

Optical chirality in AgCl-Ag thin films through formation of laser-induced planar crossed-chain nanostructures

Science.gov (United States)

Nahal, Arashmid; Kashani, Somayeh

2017-09-01

Irradiation of AgCl-Ag thin films by a linearly polarized He-Ne laser beam results in the formation of self-organized periodic nanostructures. As a result of secondary irradiation of the initially exposed sample by the same linearly polarized He-Ne laser beam, but with different orientations of polarization, a complex crossed-chain nanostructure forms. We found that such a complex nanostructure has noticeable chirality and increased optical anisotropy, resulting in optical activity of the sample. Double exposure produces two gratings, crossing each other with angle α, which leads to the formation of crossed building blocks with chiroptical effects. It is established that the amount and the sign of the angle between the two laser-induced gratings (±α) determine the amount and the direction of rotation of the linearly polarized probe beam, respectively. We have also observed an induced anisotropy-dependent ellipticity for the probe light, which is passed through the sample. It is shown that the amount of ellipticity depends on the angle α.

Response of antioxidant defense system to laser radiation apical meristem of Isatis indigotica seedlings exposed to UV-B.

Science.gov (United States)

Chen, Yi-Ping

2009-07-01

To determine the response of antioxidant defense system to laser radiation apical meristem of Isatis indigotica seedlings, Isatis indigotica seedlings were subjected to UV-B radiation (10.08 kJ m(-2)) for 8 h day(-1) for 8 days (PAR, 220 micromol m(-2) s(-1)) and then exposed to He-Ne laser radiation (633 nm; 5.23 mW mm(-2); beam diameter: 1.5 mm) for 5 min each day without ambient light radiation. Changes in free radical elimination systems were measured, the results indicate that: (1) UV-B radiation enhanced the concentration of Malondialdahyde (MDA) and decreased the activities of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) in seedlings compared with the control. The concentration of MDA was decreased and the activities of SOD, CAT and POD were increased when seedlings were subjected to elevated UV-B damage followed by laser; (2) the concentration of UV absorbing compounds and proline were increased progressively with UV-B irradiation, laser irradiation and He-Ne laser irradiation plus UV-B irradiation compared with the control. These results suggest that laser radiation has an active function in repairing UV-B-induced lesions in seedlings.

Two-wavelength HeNe laser interferometer

International Nuclear Information System (INIS)

Granneman, E.H.A.

1981-01-01

This paper presents an interferometer set-up in which two wavelengths are used simultaneously. This enables one to determine separately the phase shifts caused by changes in plasma density and by mechanical vibrations of the interferometer structure

Effects of pre-sowing laser stimulation on sowing value of lucerne seeds

International Nuclear Information System (INIS)

Dziwulska, A.

2006-01-01

Seeds of alfalfa c.v. Legend and hybrid alfalfa c.v. Radius were irradiated with divergent He-Ne laser bundle and sown on Petri dishes with four repetitions. Germination lasted for 10 days at a constant temperature 20 +- 1 deg C. Seeds germinating normally, abnormally, hard seeds and those infected with pathogenic fungi were determined. The number of seeds germinating normally increased and hard seeds decreased upon laser stimulation [pl

Design and construction of single path Raman laser

International Nuclear Information System (INIS)

Mavaddat, M.; Soltanolkotabi, M.

2007-01-01

In this paper the stimulated Raman effect has been reported.The pumping laser in this setup is He-Ne with wavelength of 632.8 nm. The first order Stokes line has been observed, to be at 776 nm. The pressure of methane gas in this setup has been increased to 20 bar. The diagram of the effect of the intensity of first order Stokes line as a function of pressure has been plotted. Also, two different pumping laser powers have been used in these investigations. Intensity of first order Stokes line has been increased with increasing gas pressure or laser power.

Discharge characteristics of He-Ne-Xe gas mixture with varying Xe contents and at varying sustain electrode gap lengths in the plasma display panel

International Nuclear Information System (INIS)

Kwon, Ohyung; Whang, Ki-Woong; Bae, Hyun Sook

2009-01-01

The discharge characteristics of He-Ne-Xe gas mixture in the plasma display panel were investigated using a two-dimensional numerical simulation to understand the effects of adding He and varying the Xe contents in the gas mixture, and also varying sustain electrode gap. With 5% Xe content and 60 μm sustain electrode gap, decreased ionization led to the improvement of the vacuum ultraviolet (vuv) efficacy at increasing He mixing ratios. However, at 20% Xe content and 60 μm sustain electrode gap, increased electron heating improved the vuv efficacy until the He mixing ratio reached 0.7, but the efficacy decreased beyond the ratio of 0.7 due to the increased ionization of Xe atoms. At 5% Xe content and 200 μm sustain electrode gap, the vuv efficacy increased as a result of increased electron heating at the gap space at increasing He mixing ratios.

Laser-sheet imaging of HE-driven interfaces

International Nuclear Information System (INIS)

Benjamin, R.F.; Rightley, P.M.; Kinkead, S.; Martin, R.A.; Critchfield, R.; Sandoval, D.L.; Holmes, R.; Gorman, T.

1998-01-01

This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The authors made substantial progress in developing the MILSI (Multiple Imaging of Laser-Sheet Illumination) technique for high explosive (HE)-driven fluid interfaces. They observed the instability, but have not yet measured the instability growth rate. They developed suitable sample containers and optical systems for studying the Rightmyer-Meshkov instability of perturbed water/bromoform interfaces and they successfully fielded the new MILSI diagnostic at two firing-site facilities. The problem continues to be of central importance to the inertial confinement fusion (ICF) and weapons physics communities

Cosmogenic He and Ne in chondrules from clastic matrix and a lithic clast of Murchison: No pre-irradiation by the early sun

Science.gov (United States)

Riebe, My E. I.; Huber, Liliane; Metzler, Knut; Busemann, Henner; Luginbuehl, Stefanie M.; Meier, Matthias M. M.; Maden, Colin; Wieler, Rainer

2017-09-01

Whether or not some meteorites retain a record of irradiation by a large flux of energetic particles from the early sun in the form of excesses of cosmic-ray produced noble gases in individual crystals or single chondrules is a topic of ongoing debate. Here, we present He and Ne isotopic data for individual chondrules in Murchison, a chondritic regolith breccia of the CM group. We separated 27 chondrules from a clastic matrix portion and 26 chondrules from an adjacent single so-called "primary accretionary rock" (Metzler et al., 1992). All chondrules from the primary rock fragment are expected to share a common irradiation history, whereas chondrules from the clastic matrix were stirred in the regolith independently of each other. All "primary rock chondrules" and 23 of the "matrix chondrules" have very similar concentrations of cosmogenic 3He and 21Ne, corresponding to a cosmic-ray exposure age to galactic cosmic rays (GCR) of ∼1.3-1.9 Ma, in the range of Murchison's meteoroid exposure age determined with cosmogenic radionuclides. Four clastic matrix chondrules contain excesses of cosmogenic 3He and 21Ne, corresponding to nominal 4π exposure ages of ∼4-∼29 Ma, with a Ne isotopic composition as expected for production by GCR. If the fraction of excess cosmogenic gas bearing chondrules in the primary rock and clastic matrix were the same, we would expect this result with a statistical probability of only 0.5 - 2.7%. Therefore, the exposure age distributions for Murchison chondrules in primary rock and clastic matrix are very likely different. Such a difference is expected if the excess cosmogenic gas was acquired by some of the matrix chondrules in the regolith, but not if chondrules were irradiated in the solar nebula by the early sun before they accreted on the Murchison parent body. Therefore, Murchison does not provide evidence for irradiation by a high fluence of energetic particles from the early sun. By inference, this statement likely holds for the

A review of monochromatic light devices for the treatment of alopecia areata.

Science.gov (United States)

Darwin, Evan; Arora, Harleen; Hirt, Penelope A; Wikramanayake, Tongyu Cao; Jimenez, Joaquin J

2018-02-01

There are many laser technologies that are being tested that claim to support hair regrowth for patients with alopecia areata (AA). In this paper, we will determine whether the body of evidence supports the use of devices using monochromatic light sources to treat AA. Articles were gathered from PubMed, Embase, and the Cochrane database using these keywords: lasers, excimer laser, low-level laser therapy (LLLT), low-level light therapy, alopecia, alopecia areata, and hair loss with a category modifier of English. Ten clinical trials and seven case reports/abstracts were assessed. Eight clinical trials and two case reports demonstrated hair regrowth with the 308-nm excimer laser/light in men, women, and children. One case report demonstrated hair regrowth with the ALBA 355® laser. One clinical trial and two case reports demonstrated hair regrowth with LLLT. While two case reports demonstrated hair regrowth with fractional laser therapy, one clinical trial showed no improvement. The 308-nm excimer laser is a safe and effective treatment for men, women, and children with refractory AA of the scalp and beard. Larger, double-blinded clinical trials should be conducted to compare excimer laser therapy to standard treatments. More data is needed to determine the efficacy of LLLT and fractional laser therapy in the treatment of AA.

Controlling nonsequential double ionization of Ne with parallel-polarized two-color laser pulses.

Science.gov (United States)

Luo, Siqiang; Ma, Xiaomeng; Xie, Hui; Li, Min; Zhou, Yueming; Cao, Wei; Lu, Peixiang

2018-05-14

We measure the recoil-ion momentum distributions from nonsequential double ionization of Ne by two-color laser pulses consisting of a strong 800-nm field and a weak 400-nm field with parallel polarizations. The ion momentum spectra show pronounced asymmetries in the emission direction, which depend sensitively on the relative phase of the two-color components. Moreover, the peak of the doubly charged ion momentum distribution shifts gradually with the relative phase. The shifted range is much larger than the maximal vector potential of the 400-nm laser field. Those features are well recaptured by a semiclassical model. Through analyzing the correlated electron dynamics, we found that the energy sharing between the two electrons is extremely unequal at the instant of recollison. We further show that the shift of the ion momentum corresponds to the change of the recollision time in the two-color laser field. By tuning the relative phase of the two-color components, the recollision time is controlled with attosecond precision.

On the Baldwin effect of He II emission lines in WR (WN) stars

OpenAIRE

van Gent, J. I.; Lamers, H. J. G. L. M.; de Koter, A.; Morris, P. W.

2001-01-01

We investigate the relation between the equivalent width of He ii emission lines and the monochromatic continuum luminosity at the line wavelength in the spectra of Wolf-Rayet stars. Model stellar atmospheres and spectra are used to show that the equivalent width inversely correlates with the monochromatic continuum luminosity. We find the effect in Wolf-Rayet star models over a large range of stellar parameters. The effect is shown to be connected to density differences among Wolf-Rayet star...

Test results of the experimental laser device for potato tubers radiation treatment

International Nuclear Information System (INIS)

Anufrik, S.S.; Korzun, O.S.

2007-01-01

Results of 3 year investigation of the influence of the presowing low intensity laser radiation treatment of potato (Solanum tuberosum L.) tubers with the help of laser device with various spectral composition and exposition on plant growth, development and productivity and potato tubers quality and starch content in the conditions of the Republic of Belarus were presented. Presowing tubers treatment of potato cultivars Sante, Yavar and Arkhideya was realized by He-Ne, Ar-, Cu (in course of 3 and 5 minutes) and CO2 (in course of 5 seconds) lasers. Research results have shown that presowing treatment with CO2 laser promoted the higher (on 1,7-6,6%) potato germination capacity in comparison with the control variant without radiation treatment. Height of potato plants of Sante variety after radiation treatment fell behind the control ones. Haulm quantity per one plant and yield quality did not depend on radiation treatment Treatment with CO2 laser exercised the stimulatory action on productivity of Sante variety without changing the starch content in tubers. Tuber weight increased up to 0,4 kg (0,2 kg in the control variant). Similar effect for Arkhideya and Yavar varieties was obtained after Cu-laser treatment in course of 5 minutes. Radiation treatment with He-Ne laser caused the increased starch accumulation (on 0,4-0,6% in comparison with the control variant) in potato tubers of all studied varieties

Formation and migration properties of the rare gases He, Ne, Ar, Ke, and Xe in nickel

International Nuclear Information System (INIS)

Melius, C.F.; Wilson, W.D.; Bisson, C.L.

1980-01-01

The energies of formation and migration of various rare gas-point defect complexes in an f.c.c. nickel lattice have been calculated for He, Ne, Ar, Kr, and Xe. Formation energies of rare gas atoms at interstitial sites are compared with those in substitutional sites. Binding energies are presented for self-interstitials and vacancies trapped to the various rare gas substitutionals. Migration energies and migration paths are also presented for various rare gas interstitials and substitutionals with and without trapped vacancies and self-interstitials. The migration energies are compared with the breakup energies for the corresponding complexes. It is found that divacancy-rare gas complexes are rather stable and will migrate at relatively low energies compared to other substitutional rare gas migration processes. (author)

Studies on auger enhancement of biological systems with the use of monochromatic synchrotron radiation

International Nuclear Information System (INIS)

Shinohara, K.

1985-01-01

HeLa cells were incubated either with BrdUrd (5 x 10 -5 M) and deoxycytidine (10 -5 M) for 18 hr (corresponding to one generation time) or with gallium citrate (10 -5 M) for 24 hr. The cells on the membrane filter were irradiated with monochromatic synchrotron radiation at 0.90 A, 1.00 A, or 1.14 A and cell survival was determined by colony-forming ability. The results show that the sensitivity of BrdUrd-labeled cells was higher when they were irradiated at 0.90 a than at 100 A, but cells without BrdUrd showed no difference in sensitivity when irradiated at these two wavelengths. The growth curve of HeLa cells in the presence of gallium citrate (10 -4 M). Shows that during the test period of 20-60 hr of colony-forming ability was not affected although the growth rate decreased slightly. Data show no increase in the sensitivity of gallium-labeled HeLa cells over that of controls to irradiation with monochromatic synchrotron radiation at 1.14 A, slightly shorter than the K absorption edge for the gallium (1.196 A). Since gallium has been shown to concentrate in lysosome, the present results, suggest that the range of Auger enhancement is not great enough for interaction with DNA in nucleus from lysosome in cytoplasm, although the possibility should be considered that the accumulated number of gallium atoms (∼ 5 x 10 7 /cell) may not be enough to produce detectable enhancement effects

Efficacy of Proliferation of HeLa Cells under Three Different Low-Intensity Red Lasers Irradiation

Directory of Open Access Journals (Sweden)

H. Q. Yang

2012-01-01

Full Text Available This study was intended to compare the efficacy of proliferation of HeLa cells under three different low-intensity laser irradiation (LIL, that is, 633 nm, 658 nm, and 785 nm. The time-dependent responses of proliferation of HeLa cells after the red laser irradiation and the influence of fetal bovine serum (FBS at 1%, 2%, 5%, or 10% on the proliferation of cells were also investigated. The results indicated that the proliferation of HeLa cells in 10% FBS was in proliferation-specific homeostasis (PSH so that it was not modulated with LIL; the proliferation in FBS at 1%, 2%, or 5% was far from PSH so that it may be wavelength dependently modulated with LIL, and the maximum proliferation promotion was conducted with LIL at 633 nm amongst the three different LIL. It was concluded the wavelength-dependent photobiomodulation of LIL on proliferation of HeLa cells may be homeostatic.

Rotational energy transfer in Na2 (A Σ) colliding with Xe, Kr, Ar, Ne, He, H2, CH4, and N2: Experiment and fitting laws

International Nuclear Information System (INIS)

Brunner, T.A.; Smith, N.; Karp, A.W.; Pritchard, D.E.

1981-01-01

Using the method of laser-induced fluorescence, we have measured level to level rate constants for rotational energy transfer (RET) in Na 2 colliding with Xe, Kr, Ar, Ne, He, H 2 , N 2 , and CH 4 . For each target gas we varied the initial rotational quantum number ji-italic over a wide range, typically 4--100, and measured approximately 60 rate constants with an average error of between 6% and 9%. The resulting base of 479 rate constants is used to test several recently proposed fitting laws. The energy corrected sudden scaling law of DePristo et al., when combined with the assumption of a power gap law for the basis rate constants k/sub l/→0, fit with only 3 parameters all of the data for a given target gas with 7%--12% average percentage deviation. Our statistical power gap law worked well and was generally the best law for those data sets with only one value of j/sub i/. The worst fits in all cases considered here were those using the exponential gap law of surprisal theory

Frequency Noise Properties of Lasers for Interferometry in Nanometrology

Directory of Open Access Journals (Sweden)

Ondřej Číp

2013-02-01

Full Text Available In this contribution we focus on laser frequency noise properties and their influence on the interferometric displacement measurements. A setup for measurement of laser frequency noise is proposed and tested together with simultaneous measurement of fluctuations in displacement in the Michelson interferometer. Several laser sources, including traditional He-Ne and solid-state lasers, and their noise properties are evaluated and compared. The contribution of the laser frequency noise to the displacement measurement is discussed in the context of other sources of uncertainty associated with the interferometric setup, such as, mechanics, resolution of analog-to-digital conversion, frequency bandwidth of the detection chain, and variations of the refractive index of air.

Charge Exchange of Highly Charged Ne and Mg Ions with H and He

Science.gov (United States)

Lyons, D.; Cumbee, R. S.; Stancil, P. C.

2017-10-01

Cross sections for single electron capture (SEC), or charge exchange (CX), in collisions of Ne(8-10)+ and Mg(8-12)+ with H and He, are computed using an approximate multichannel Landau-Zener (MCLZ) formalism. Final-state-resolved cross sections for the principal (n), orbital angular momentum (ℓ), and where appropriate, total spin angular momentum (S) quantum numbers are explicitly computed, except for the incident bare ions Ne10+ and Mg12+. In the latter two cases, n{\\ell }-resolution is obtained from analytical ℓ-distribution functions applied to n-resolved MCLZ cross sections. In all cases, the cross sections are computed over the collision energy range 1 meV/u to 50 keV/u with LZ parameters estimated from atomic energies obtained from experiment, theory, or, in the case of high-lying Rydberg levels, estimated with a quantum defect approach. Errors in the energy differences in the adiabatic potentials at the avoided crossing distances give the largest contribution to the uncertainties in the cross sections, which are expected to increase with decreasing cross section magnitude. The energy differences are deduced here with the Olson-Salop-Tauljberg radial coupling model. Proper selection of an ℓ-distribution function for bare ion collisions introduces another level of uncertainty into the results. Comparison is made to existing experimental or theoretical results when available, but such data are absent for most considered collision systems. The n{\\ell }S-resolved SEC cross sections are used in an optically thin cascade simulation to predict X-ray spectra and line ratios that will aid in modeling the X-ray emission in environments where CX is an important mechanism. Details on a MCLZ computational package, Stueckelberg, are also provided.

The effect of green helium-neon laser on the healing of extraction wounds: histological study in rats

International Nuclear Information System (INIS)

Nicolli Filho, Walter Domingos; Picon, Luciana Christofolini; Okamoto, Tetuo; Cardenuto, Ney

1993-01-01

A histological study on healing of extraction wounds following laser irradiation, using a green He-Ne laser, was carried out in rats. The results suggest that this kind of treatment has no significant beneficial effect on bony wound healing. Proliferation of fibroblasts and formation of trabecular osteoid were found to be not more pro eminent within the irradiated group. (author)

Laser Technology Is Primed for the Classroom.

Science.gov (United States)

Lytle, Jim

1986-01-01

Explains the three characteristics of laser light (monochromatic light, divergence, and coherence), the components of a laser, applications of the laser (alignment, distance measurement, welding/cutting, marking, medical applications), and a complete laser training system appropriate for classroom use. (CT)

Transition from hydrodynamic to fast sound in a He-Ne mixture a neutron Brillouin scattering experiment

CERN Document Server

Bafile, U; Barocchi, F; Sampoli, M

2002-01-01

The presence of a fast-sound mode in the microscopic dynamics of the rare-gas mixture He-Ne, predicted by theoretical studies and molecular-dynamics simulations, was demonstrated by an inelastic neutron scattering experiment. In order to study the transition between the fast and the normal acoustic modes in the hydrodynamic regime, k values lower by about one order of magnitude than in the usual experiments have to be probed. We describe here the results of the first neutron Brillouin scattering experiment performed with this purpose on the same system already investigated at larger k. The results of both experiments, together with those of a new molecular-dynamics simulation, provide a complete and consistent description, still missing so far, of the onset of fast-sound propagation in a binary mixture. (orig.)

Response-function measurement of an NE213 scintillator using the [sup 2]H(d, n)[sup 3]He reaction

Energy Technology Data Exchange (ETDEWEB)

Aksoy, A. (Energy Research Lab., King Fahd Univ. of Petroleum and Minerals, Dhahran (Saudi Arabia)); Coban, A. (Energy Research Lab., King Fahd Univ. of Petroleum and Minerals, Dhahran (Saudi Arabia)); Naqvi, A.A. (Energy Research Lab., King Fahd Univ. of Petroleum and Minerals, Dhahran (Saudi Arabia)); Khiari, F.Z. (Energy Research Lab., King Fahd Univ. of Petroleum and Minerals, Dhahran (Saudi Arabia)); Hanly, J.M. (Duke Univ., Nuclear Labs., Durham, NC (United States)); Howell, C.R. (Duke Univ., Nuclear Labs., Durham, NC (United States)); Tornow, W. (Duke Univ., Nuclear Labs., Durham, NC (United States)); Felsher, P.D. (Duke Univ., Nuclear Labs., Durham, NC (United States)); Al-Ohali, M.A. (Duke Univ., Nuclear Labs., Durham, NC (United States)); Walter, R.L. (Duke Univ., Nuclear Labs., Durham, NC (United States))

1994-01-01

The response function of a 12.5 cm diameter NE213 scintillator detector has been measured over neutron energies ranging from 4.9 to 16.6 MeV. Beams of monoenergetic neutrons were produced using the [sup 2]H(d, n)[sup 3]He reaction. The response function is about 12% lower than previously reported values for a similar detector obtained using a continuous spectrum of neutrons from a [sup 252]Cf fission source. However, the present response function agrees with portions of data sets obtained in published work that used monoenergetic neutron source reactions. (orig.)

Bibliography of Soviet Laser Developments: January - February 1988

Science.gov (United States)

1989-02-21

light in LiNbO(sub3), CsH(sub2)AsO(sub4) and Ba(sub2)NaNb(sub5)O(sub 15) crystals under synchronous pumping by a picosecond La (sub2)Be(sub2)O(sub5):Nd...Weber,T. 0 Determining the metrological characteristics of an He-Ne laser at 633 nm as a secondary standard of length (in Romanian). Metrologia

CO laser interferometer for REB-plasma experiments

International Nuclear Information System (INIS)

Burmasov, V.S.; Kruglyakov, E.P.

1996-01-01

The Michelson carbon oxide laser interferometer for measuring plasma density in studies on REB-plasma interaction is described. A detail description of the interferometer and CO laser is presented. For a selection of a single wavelength laser operation the CaF 2 prism is applied. A Ge:Au photoconductor at 77 deg K is applied as the detector. The CO laser radiation at λ 5.34 μm coincides with the detector maximum sensitivity (of the order of 1000 V/W). This increases the interferometer sensitivity about ten times with respect to the He-Ne laser (λ = 3.39 μm) used as the source of light. The typical interferogram and time evolution of plasma density obtained at GOL-M device are presented. (author). 3 figs., 5 refs

CO laser interferometer for REB-plasma experiments

Energy Technology Data Exchange (ETDEWEB)

Burmasov, V S; Kruglyakov, E P [Budker Inst. of Nuclear Physics, Novosibirsk (Russian Federation)

1997-12-31

The Michelson carbon oxide laser interferometer for measuring plasma density in studies on REB-plasma interaction is described. A detail description of the interferometer and CO laser is presented. For a selection of a single wavelength laser operation the CaF{sub 2} prism is applied. A Ge:Au photoconductor at 77 deg K is applied as the detector. The CO laser radiation at {lambda} 5.34 {mu}m coincides with the detector maximum sensitivity (of the order of 1000 V/W). This increases the interferometer sensitivity about ten times with respect to the He-Ne laser ({lambda} = 3.39 {mu}m) used as the source of light. The typical interferogram and time evolution of plasma density obtained at GOL-M device are presented. (author). 3 figs., 5 refs.

Gas-laser behavior in a low-gravity environment

Science.gov (United States)

Owen, R. B.

1981-01-01

In connection with several experiments proposed for flight on the Space Shuttle, which involve the use of gas lasers, the behavior of a He-Ne laser in a low-gravity environment has been studied theoretically and experimentally in a series of flight tests using a low-gravity-simulation aircraft. No fluctuation in laser output above the noise level of the meter (1 part in 1000 for 1 hr) was observed during the low-gravity portion of the flight tests. The laser output gradually increased by 1.4% during a 1.5-hr test; at no time were rapid variations observed in the laser output. A maximum laser instability of 1 part in 100 was observed during forty low-gravity parabolic maneuvers. The beam remained Gaussian throughout the tests and no lobe patterns were observed.

Effect of helium-neon laser irradiation on hair follicle growth cycle of Swiss albino mice.

Science.gov (United States)

Shukla, S; Sahu, K; Verma, Y; Rao, K D; Dube, A; Gupta, P K

2010-01-01

We report the results of a study carried out to investigate the effect of helium-neon (He-Ne) laser (632.8 nm) irradiation on the hair follicle growth cycle of testosterone-treated and untreated mice. Both histology and optical coherence tomography (OCT) were used for the measurement of hair follicle length and the relative percentage of hair follicles in different growth phases. A positive correlation (R = 0.96) was observed for the lengths of hair follicles measured by both methods. Further, the ratios of the lengths of hair follicles in the anagen and catagen phases obtained by both methods were nearly the same. However, the length of the hair follicles measured by both methods differed by a factor of 1.6, with histology showing smaller lengths. He-Ne laser irradiation (at approximately 1 J/cm(2)) of the skin of both the control and the testosterone-treated mice was observed to lead to a significant increase (p alopecia. (c) 2009 S. Karger AG, Basel.

Analysis and manipulation of atomic and molecular collisions using laser light

International Nuclear Information System (INIS)

Grimpe, A.

2006-01-01

Optical collisions in a crossed beam experiment are examined for the atomic collision pairs LiHe, LiNe, NaNe. Differential cross sections are measured in order to probe the quality of quantum chemical calculated and spectroscopical determined molecular potentials. The linear polarization of the excitation laser is used to manipulate the contrast of the differential cross sections for NaNe. Using elliptical polarized light total control over the angular position and the contrast of the interference pattern is demonstrated. Differential cross sections for the collision pairs LiH 2 and LiD 2 show a pronounced oscillatory structure, which for the first time is observed for atom-molecule optical collisions. (orig.)

Sequential double photodetachment of He- in elliptically polarized laser fields

Science.gov (United States)

Génévriez, Matthieu; Dunseath, Kevin M.; Terao-Dunseath, Mariko; Urbain, Xavier

2018-02-01

Four-photon double detachment of the helium negative ion is investigated experimentally and theoretically for photon energies where the transient helium atom is in the 1 s 2 s 3S or 1 s 2 p P3o states, which subsequently ionize by absorption of three photons. Ionization is enhanced by intermediate resonances, giving rise to series of peaks in the He+ spectrum, which we study in detail. The He+ yield is measured in the wavelength ranges from 530 to 560 nm and from 685 to 730 nm and for various polarizations of the laser light. Double detachment is treated theoretically as a sequential process, within the framework of R -matrix theory for the first step and effective Hamiltonian theory for the second step. Experimental conditions are accurately modeled, and the measured and simulated yields are in good qualitative and, in some cases, quantitative agreement. Resonances in the double detachment spectra can be attributed to well-defined Rydberg states of the transient atom. The double detachment yield exhibits a strong dependence on the laser polarization which can be related to the magnetic quantum number of the intermediate atomic state. We also investigate the possibility of nonsequential double detachment with a two-color experiment but observe no evidence for it.

Effects of Ar and He on Microstructures and Properties of Laser Welded 800MPa TRIP Steel

Directory of Open Access Journals (Sweden)

Wang Wen-Quan

2018-01-01

Full Text Available Fiber laser welding of cold rolled TRIP steel (transformation Induced Plasticity steel sheet with tensile strength of 820MPa and thickness of 1.4mm was carried out using shielding gases Ar and He, respectively. For the same laser power and welding speed, the effects of different shielding gases on penetration and bead section morphologies were investigated. The microstructures and properties of the TRIP steel joints were also studied. The investigation showed that higher penetration and lower porosity could be obtained under shielding gas He using the same laser power and welding speed. The microstructures of the TRIP joint mainly included martensite and retained austenite. But the joint microhardness and tensile strength were higher under the shielding gas He. The tensile strength of the welded joint perpendicular to the weld line was equal to that of the base metal. But the tensile strength of the joint parallel with the weld line was higher than that of the base metal. The plasticity and formability of the welded joint were impaired due to the formation of martensite in the weld metal.

Absolute transition probabilities in the NeI 3p-3s fine structure by beam-gas-dye laser spectroscopy

International Nuclear Information System (INIS)

Hartmetz, P.; Schmoranzer, H.

1983-01-01

The beam-gas-dye laser two-step excitation technique is further developed and applied to the direct measurement of absolute atomic transition probabilities in the NeI 3p-3s fine-structure transition array with a maximum experimental error of 5%. (orig.)

Study of non-thermal effects from laser radiation on live tissues

International Nuclear Information System (INIS)

Cotta, M.A.

1987-02-01

The functional biological effects related to the irradiation of live tissues with low power lasers, called non-thermal effects were theoretical and experimentally studied. For the experimental part, a device which allows to: irradiation lesions artificially created on the back of rats by a He-Ne laser, or put a moving ground glass in front of the laser beam, by irradiation of this same laser with its coherence degree decreased. The relevance of the radiation coherence in the lesion cicatrization process was shown. The electrical field distribution and the intensity distribution on a surface with micro-roughness when irradiated by coherent light are theoretically studied. (M.C.K.) [pt

Investigations of an excimer laser working with a four-component gaseous mixture He-Kr:Xe-HCl

Science.gov (United States)

Iwanejko, Leszek; Pokora, Ludwik J.

1991-08-01

The paper presnts working conditions of an XCI excimer laser untypical gas mixture based on KrzXe instead of pure Xe. Such a choice was influenced by the necessity of Findin9 the way to replace imported and expensive Xe by gaseous components accesible in Poland. Determining the range of changes of laser extrnal parameters which enables its proper work with the new gas mixture was the aim of same investigations results of which are presented in this paper. The laser pulse output energy and the pulse duration as a Function of supply voltage and the mixture composition are presented. The range of proper conditions for the laser working with the new mixture He-Kr:Xe--HC1 was determined. The analysis of experimental results showed that using the new mixture ensures value of energy and pulse duration comparable with the ones obtained for the mixture He-''Xe--HCl. Spectral investigations showed the lack of influence of Kr presence in the mixture on the generation spectrum of the laser. L.

Test of sup 3 He-based neutron polarizers at NIST

CERN Document Server

Jones, G L; Thompson, A K; Chowdhuri, Z; Dewey, M S; Snow, W M; Wietfeldt, F E

2000-01-01

Neutron spin filters based on polarized sup 3 He are useful over a wide neutron energy range and have a large angular acceptance among other advantages. Two optical pumping methods, spin-exchange and metastability-exchange, can produce the volume of highly polarized sup 3 He gas required for such neutron spin filters. We report a test of polarizers based on each of these two methods on a new cold, monochromatic neutron beam line at the NIST Center for Neutron Research.

Fine and hyperfine structure spectra of the ultra-violet 23S → 53P transition in 4He and 3He with a frequency doubled CW ring laser, detected via associative ionization

International Nuclear Information System (INIS)

Runge, S.; Pesnelle, A.; Perdrix, M.; Sevin, D.; Wolffer, N.; Watel, G.

1982-01-01

High resolution laser spectroscopy coupled to a sensitive method of detection via mass analysis of He + 2 ions produced in He(5 3 P) + He(1 1 S) collisions, is used to obtain the fine and hyperfine spectra of the ultra-violet He 2 3 S → 5 3 P transition. A cw tunable UV radiation around 294.5 nm is generated by intracavity frequency doubling a Rhodamine 6G single mode ring dye laser using an ADA crystal. Both spectra enable fine and hyperfine structures to be determined within a few MHz. The magnetic dipole coupling constant A of the 5 3 P term of 3 He is found to be -4326 +- 9 MHz (-0.1443 +- 0.0003 cm -1 ). (orig.)

Correlated Keldysh-Faisal-Reiss theory of above-threshold double ionization of He in intense laser fields

International Nuclear Information System (INIS)

Becker, A.; Faisal, F.H.M.

1994-01-01

We have developed a correlated Keldysh-Faisal-Reiss theory of laser-induced double ionization of a two-electron atom. The basic N-photon T matrix and the expression for N-photon triple-differential rates or cross sections (TDCS's) are derived. The theory is applied to investigate the TDCS's for very-high-order multiphoton double ionization of He with lasers of wavelength λ=248 nm and λ=617 nm. Comparison with the uncorrelated results reveals a dramatic influence of the final-state e-e correlation on the above-threshold TDCS's to be measured in coincidence experiments in intense laser fields. The limiting case of the TDCS's for weak-field double ionization of He by a synchrotron photon is also investigated; the results confirm the earlier theoretical findings and recent experimental results in that case

Noble Gases in Alpine Gold: U/Th-He Dating and Excesses of Radiogenic He and AR

Science.gov (United States)

Eugster, O.; Hofmann, B.; Krahenbuhl, U.; Neuenschwander, J.

1992-07-01

Gold precipitates in hydrothermal fluids along with other heavy elements, such as Ag and Pt. In order to explore the possibility of dating the formation of gold we determined the concentrations of U, Th, and their decay product ^4He, as well as the K and ^40Ar concentrations in vein-type gold and in placer gold samples. The gold-quartz veins at Brusson in the south-western alps were formed approximately 32 Ma ago during an episode of tectonic uplift (Diamond, 1990). Alpine material was deposited as sediment layers in the region of central Switzerland and placer gold is thus relatively abundant in the rivers of the Napf area. We washed placer gold from the river Grosse Fontanne in 1990 and 1991. Placer gold that had been collected from the river Kruempelgraben in 1933 and a sample of vein-type free gold grown on quartz rock from the Brusson area (Val d'Ayas) have been obtained from the Museum of Natural History in Bern. Table 1 gives the results. Most of the ^4He is released above 1050 degrees C, that is when gold melts, indicating that gold is extremely well retentive for He. From the ^4He concentration of (269 +- 20) x 10^-8 cm^3 STP/g, (0.4 +- 0.1) ppm U, and (0.9 +- 0.3) ppm Th for vein-type gold we calculate a U/Th-He age of (36 +- 8)Ma. This age agrees within errors with the proposed age of 32 Ma. The data given in Table 1 show that all placer gold samples contain excesses of radiogenic ^4He and ^40Ar relative to the concentrations expected from the U/Th and K decay, respectively, if we assume a formation age of 32 Ma. The quartz sample is depleted in ^4He but strongly enriched in radiogenic ^40Ar. The excess of ^40Ar(sub)rad is easier to explain than that of ^4He. Vein-type gold and placer gold contain quartz inclusions (Schmid, 1973). The high ^40Ar(sub)rad content of quartz (Table 1) indicates that the ^40Ar(sub)rad excess of gold originates from quartz inclusions. Excess ^4He in gold must be of radiogenic origin. Taking ^20Ne and ^36Ar as a measure for the

White light photothermal lens spectrophotometer for the determination of absorption in scattering samples.

Science.gov (United States)

Marcano, Aristides; Alvarado, Salvador; Meng, Junwei; Caballero, Daniel; Moares, Ernesto Marín; Edziah, Raymond

2014-01-01

We developed a pump-probe photothermal lens spectrophotometer that uses a broadband arc-lamp and a set of interference filters to provide tunable, nearly monochromatic radiation between 370 and 730 nm as the pump light source. This light is focused onto an absorbing sample, generating a photothermal lens of millimeter dimensions. A highly collimated monochromatic probe light from a low-power He-Ne laser interrogates the generated lens, yielding a photothermal signal proportional to the absorption of light. We measure the absorption spectra of scattering dye solutions using the device. We show that the spectra are not affected by the presence of scattering, confirming that the method only measures the absorption of light that results in generation of heat. By comparing the photothermal spectra with the usual absorption spectra determined using commercial transmission spectrophotometers, we estimate the quantum yield of scattering of the sample. We discuss applications of the device for spectroscopic characterization of samples such as blood and gold nanoparticles that exhibit a complex behavior upon interaction with light.

2He decay from excited states: the 18Ne case

International Nuclear Information System (INIS)

Raciti, G.; Sfienti, C.; De Napoli, M.; Rapisarda, E.; Cardella, G.; Giacoppo, F.

2011-01-01

Two-proton radioactivity studies have been performed on excited states of 18 Ne produced by 20 Ne fragmentation at the FRIBs facility of the Laboratori Nazionali del Sud. The study of the relative-momentum correlations of the two protons allowed to disentangle the diproton, democratic and sequential decay contributions to the 2p emission. In order to extend the study on two-proton decay to other light-masses nuclei, an upgrade of the FRIBs facility is planned. A new configuration of the Fragment Separator would be able to increase the acceptance of the beam line and therefore the yield of the produced radioactive beams. Also the present tagging setup will be modified in view of the gain intensity, in order to sustain the higher foreseen incoming rate. Status and perspectives of the facility will be presented. (author)

Influence of the He-Ne laser in different irradiation regimes on the cornea cells after ionizing irradiation

International Nuclear Information System (INIS)

Bulyakova, N.V.

1984-01-01

A study was made on epithelium cells of the eye cornea in mices entering the first postradiation mitosis. The influence of laser rays acting in the course of each exposure during one and the same period of time, or continuously, or by pulses was compared. The effect of laser radiation was evaluated from the frequency of occurrence of cells with chromosomal aberrations, mitotic index, coefficient of mitosis phases. It has been established that pulse radiation of a helium-neon laser in a certain operation regime produces a sanitating effect on cells of eye cornea epithelium in white mice damaged by ionizing radiation. Cells being killed in the interphase were not revealed in epithelium of the eye cornea. It enables to conclude that the amount of aberrant mitoses decreases as a result of postradiation repair of cells damaged by ionizing radiation, but not as a result of their elimination

Investigation of collisional excitation-transfer processes in a plasma by laser perturbation method

International Nuclear Information System (INIS)

Sakurai, Takeki

1983-01-01

The theoretical background and the experimental method of the laser perturbation method applied to the study of collisional excitation transfer process in plasma are explained. The atomic density at some specified level can be evaluated theoretically. By using the theoretical results and the experimentally obtained data, the total attenuation probability, the collisional transfer probability and natural emission probability were estimated. For the experiments, continuous wave laser (cw) and pulse laser are employed. It is possible by using pulse dye laser to observe the attenuation curve directly, and to bring in resonance to any atomic spectra. At the beginning, the experimental studies were made on He-Ne discharge. The pulse dye laser has been used for the excitation of alkali atoms. The first application of pulse laser to the study of plasma physics was the study on He. The cross section of disalignment has also been studied by the laser perturbation. The alignment of atoms, step and cascade transfer, the confinement of radiation and optogalvanic effect are discussed in this paper. (Kato, T.)

The effect of broad-band Alfven-cyclotron waves spectra on the preferential heating and differential acceleration of He{sup ++} ions in the solar wind

Energy Technology Data Exchange (ETDEWEB)

Maneva, Y. G. [Department of Physics, Catholic University of America, Washington DC, 20064 (United States) and Heliophysics Science Devision, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Ofman, L. [Department of Physics, Catholic University of America, Washington, DC 20064 (United States) and Heliophysics Science Devision, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Vinas, A. F. [Heliophysics Science Devision, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

2013-06-13

In anticipation of results from inner heliospheric missions such as the Solar Orbiter and the Solar Probe we present the results from 1.5D hybrid simulations to study the role of magnetic fluctuations for the heating and differential acceleration of He{sup ++} ions in the solar wind. We consider the effects of nonlinear Alfven-cyclotron waves at different frequency regimes. Monochromatic nonlinear Alfven-alpha-cyclotron waves are known to preferentially heat and accelerate He{sup ++} ions in collisionless low beta plasma. In this study we demonstrate that these effects are preserved when higherfrequency monochromatic and broad-band spectra of Alfven-proton-cyclotron waves are considered. Comparison between several nonlinear monochromatic waves shows that the ion temperatures, anisotropies and relative drift are quantitatively affected by the shift in frequency. Including a broad-band wave-spectrum results in a significant reduction of both the parallel and the perpendicular temperature components for the He{sup ++} ions, whereas the proton heating is barely influenced, with the parallel proton temperature only slightly enhanced. The differential streaming is strongly affected by the available wave power in the resonant daughter ion-acoustic waves. Therefore for the same initial wave energy, the relative drift is significantly reduced in the case of initial wave-spectra in comparison to the simulations with monochromatic waves.

Monooxignase ensymic system of a liver of rats exposed to intravascular laser irradiation of blood

International Nuclear Information System (INIS)

Ibadova, G.A.

1997-01-01

Experimental study of the dynamic monooxidation of liver enzymic system was carried out on rats with experimental salmonellosis and the influence of the blood intravascular laser irradiation of blood on these enzymes was revealed. It was determined that by experimental salmonellosis oppression of the MOES activity of hepatocytes occurred. The blood intravascular irradiation by He-Ne laser promotes MOES oppression in rats suffered from salmonellosis. IVLIB as well as UV-laser show pronounced effect on the enzymes detoxication protection, mobilize their resistance to endogenic intoxication under the conditions of experimental salmonellosis. (author)

Coupled cluster calculations of mean excitation energies of the noble gas atoms He, Ne and Ar and of the H2 molecule

DEFF Research Database (Denmark)

Sauer, Stephan P. A.; Ul Haq, Inam; Sabin, John R.

2014-01-01

by about 1%. For the two-electron systems He and H2, our CCSD results (for a Lanczos chain length equal to the full excitation space), I0 = 42:28 eV (Helium) and I0 = 19:62 eV (H2), correspond to full conguration interaction results and are therefore the exact, non-relativistic theoretical values......Using an asymmetric-Lanczos-chain algorithm for the calculation of the coupled cluster linear response functions at the CCSD and CC2 levels of approximation, we have calculated the mean excitation energies of the noble gases He, Ne and Ar, and of the hydrogen molecule H2. Convergence with respect...... for the mean excitation energy of these two systems within the Bethe theory for the chosen basis set and, in the case of H2, at the experimental equilibrium geometry....

Pulsed inductive HF laser

Energy Technology Data Exchange (ETDEWEB)

Razhev, A M; Kargapol' tsev, E S [Institute of Laser Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk (Russian Federation); Churkin, D S; Demchuk, S V [Novosibirsk State University, Novosibirsk (Russian Federation)

2016-03-31

We report the results of experimentally investigated dependences of temporal, spectral and spatial characteristics of an inductive HF-laser generation on the pump conditions. Gas mixtures H{sub 2} – F{sub 2}(NF{sub 3} or SF6{sub 6}) and He(Ne) – H{sub 2} – F{sub 2}(NF{sub 3} or SF{sub 6}) were used as active media. The FWHM pulse duration reached 0.42 μs. This value corresponded to a pulsed power of 45 kW. For the first time, the emission spectrum of an inductive HF laser was investigated, which consisted of seven groups of bands with centres around the wavelengths of 2732, 2736, 2739, 2835, 2837, 2893 and 2913 nm. The cross section profile of the laser beam was a ring with a diameter of about 20 mm and width of about 5 mm. Parameters of laser operation in the repetitively pulsed regime were sufficiently stable. The amplitude instability of light pulses was no greater than 5% – 6%. (lasers)

Comment on "Collision monochromatization in e+e- colliders"

Science.gov (United States)

Shatilov, D.

2018-02-01

Bogomyagkov and Levichev [Phys. Rev. Accel. Beams 20, 051001 (2017), 10.1103/PhysRevAccelBeams.20.051001] have recently reported on monochromatization in collision schemes with crossing angle. From their results, in particular, it may seem that: (1) horizontal dispersion at the IP can provide monochromatization factor Λ ≫1 while retaining Piwinski angle ϕ >1 , (2) production rate in such a scheme for FCC-ee at 62.5 GeV can be larger than that in the nominal crab waist collision, and (3) strong rf focusing can be used for monochromatization purposes. We demonstrate here that the first two statements are not correct, and the last one is very doubtful.

Spectroscopy Stress Evaluation of Translucid Polymers Using Laser Photoelasticity

Science.gov (United States)

Treviño, Marciano Vargas; Gil, Aarón Flores; Rodríguez-Lelis, J. M.; González, Antonio Hernández; Arvizo, Dagoberto Vela; Alarcón, Manuel May; Pliego, Arturo Abundez

2008-04-01

Several studies can be found where the mechanical strength of fiber composites is evaluated, but not much can be found regarding the influence of voids, as a second phase, in the same mechanical behavior of materials. In the present work, the influence of bubble presence into translucid polymeric bars is investigated. For this purpose, cubic probes with an anisotropic distribution of bubbles were casted, and other were casted controlling the manufacture process to avoid the bubble formation. Each probe was placed in a He-Ne laser-photoelastic arrangement and subjected to compression by an static load. The transmitted 630 nm, He-Ne laser beam was captured by a single mode fiber optic sensor and then transmitted to a spectrometer and PC. Analysis of the spectrometer signals showed that the maximum stresses are concentrated on the bubbles reducing the surface stresses and inducing damping on the probe. The amount of damping depends on the size of the bubbles formed within the probe and their arrangement, thus it can be anticipated that stresses can be directed for specific arrangements in size of bubbles. A white light was also employed in substitution of the laser to investigated the effect of wave length on the results previously obtained. The effect of damping was also experienced but although more information could be obtained caused of the non-coherent nature of the light, it was no possible to obtain full information of the structure of the probes.

Soft X-ray laser using pumping of 3P and 4P levels of He-like and H-like ions

Science.gov (United States)

Hagelstein, Peter L.

1987-01-01

X-ray laser method and apparatus for producing coherent radiation at, for example, energies of at least 40 eV, using Be-like Cr, N-like Ni, He-like Na, B-like Cr, Be-like Mn or similar multiply ionized species to pump appropriate high energy transitions in He-like or H-like N, O, F, C or rare gases, with associated laser transition gains of 4-50 cm.sup.-1.

Monochromatic x-rays for low-dose digital mammography: preliminary results.

Science.gov (United States)

Yoon, Kwon-Ha; Kwon, Young Man; Choi, Byoung-Jung; Son, Hyun Hwa; Ryu, Cheol Woo; Chon, Kwon Su; Park, Seong Hoon; Juhng, Sun Kwan

2012-12-01

The feasibility of using monochromatic x-ray imaging generated from an x-ray tube and a multilayer reflector for digital mammography with a low radiation dose was examined. A multilayer mirror was designed to select the x-ray peak with an energy of 21.5 keV generated from an x-ray tube with a tungsten target and was fabricated by the ion-beam sputtering deposition system. Monochromatic x-ray images were obtained from an experimental digital mammography setup with a scanning stage. The performance of the system was evaluated using a breast phantom, a spectrometer, and a radiation dosimeter. We measured the contrast-to-noise ratio and performed the 10% modulation function test to determine image quality and resolution. The monochromatic beam from the multilayer reflector had a full-width-at-half-maximum of 0.9 keV at 21.5 keV, and the reflectivity was 0.70, which was 90% of the designed value. The polychromatic and monochromatic x-rays showed radiation doses of 0.497 and 0.0415 mGy, respectively. The monochromatic x-ray image shows fibers, calcifications, and masses more clearly than the polychromatic x-ray images do. The image contrast of the monochromatic x-rays was 1.85 times higher than that of the polychromatic x-rays. The experimental mammography setup had a spatial resolution of 7 lp/mm with both x-rays. Monochromatic x-rays generated using a multilayer mirror may be a useful diagnostic tool for breast examination by providing high contrast imaging with a low radiation dose.

Monochromatic neutrino beams

International Nuclear Information System (INIS)

Bernabeu, Jose; Burguet-Castell, Jordi; Espinoza, Catalina; Lindroos, Mats

2005-01-01

In the last few years spectacular results have been achieved with the demonstration of non vanishing neutrino masses and flavour mixing. The ultimate goal is the understanding of the origin of these properties from new physics. In this road, the last unknown mixing [U e3 ] must be determined. If it is proved to be non-zero, the possibility is open for Charge Conjugation-Parity (CP) violation in the lepton sector. This will require precision experiments with a very intense neutrino source. Here a novel method to create a monochromatic neutrino beam, an old dream for neutrino physics, is proposed based on the recent discovery of nuclei that decay fast through electron capture. Such nuclei will generate a monochromatic directional neutrino beam when decaying at high energy in a storage ring with long straight sections. We also show that the capacity of such a facility to discover new physics is impressive, so that fine tuning of the boosted neutrino energy allows precision measurements of the oscillation parameters even for a [U e3 ] mixing as small as 1 degree. We can thus open a window to the discovery of CP violation in neutrino oscillations

Laser Ablation in situ (U-Th-Sm)/He and U-Pb Double-Dating of Apatite and Zircon: Techniques and Applications

Science.gov (United States)

McInnes, B.; Danišík, M.; Evans, N.; McDonald, B.; Becker, T.; Vermeesch, P.

2015-12-01

We present a new laser-based technique for rapid, quantitative and automated in situ microanalysis of U, Th, Sm, Pb and He for applications in geochronology, thermochronometry and geochemistry (Evans et al., 2015). This novel capability permits a detailed interrogation of the time-temperature history of rocks containing apatite, zircon and other accessory phases by providing both (U-Th-Sm)/He and U-Pb ages (+trace element analysis) on single crystals. In situ laser microanalysis offers several advantages over conventional bulk crystal methods in terms of safety, cost, productivity and spatial resolution. We developed and integrated a suite of analytical instruments including a 193 nm ArF excimer laser system (RESOlution M-50A-LR), a quadrupole ICP-MS (Agilent 7700s), an Alphachron helium mass spectrometry system and swappable flow-through and ultra-high vacuum analytical chambers. The analytical protocols include the following steps: mounting/polishing in PFA Teflon using methods similar to those adopted for fission track etching; laser He extraction and analysis using a 2 s ablation at 5 Hz and 2-3 J/cm2fluence; He pit volume measurement using atomic force microscopy, and U-Th-Sm-Pb (plus optional trace element) analysis using traditional laser ablation methods. The major analytical challenges for apatite include the low U, Th and He contents relative to zircon and the elevated common Pb content. On the other hand, apatite typically has less extreme and less complex zoning of parent isotopes (primarily U and Th). A freeware application has been developed for determining (U-Th-Sm)/He ages from the raw analytical data and Iolite software was used for U-Pb age and trace element determination. In situ double-dating has successfully replicated conventional U-Pb and (U-Th)/He age variations in xenocrystic zircon from the diamondiferous Ellendale lamproite pipe, Western Australia and increased zircon analytical throughput by a factor of 50 over conventional methods

Effect of bone marrow and low power lasers on fracture healing with destruction of both periosteum and endosteum in rabbits

Directory of Open Access Journals (Sweden)

M. G. Thanoon

2010-01-01

Full Text Available Ten mature rabbits of local breed were used in this study; weighing between 1.5 to 1.75 kg and aged about 1–2 years. These animals were divided into two equal groups; in group A destruction of both periosteum and endosteum was done one centimeter from each side of mid-shaft femoral bone fracture, then sufficient amount of autogenously bone marrow was injected directly at the fracture site after immobilization by intramedullary pin. In group B a similar procedure was achieved as in group A, but in additional to that He-Ne infrared laser therapy was used for several sessions. The result of radiological findings indicated that, the fracture healing occurred within group B at fifteen weeks, whereas in group A the healing occurred at eighteen weeks after operation. The implantation of autologous bone marrow enhanced the fracture healing, whereas using of combinations of autologous bone marrow and He-Ne infrared laser therapy hastened the healing.

Designing and testing a laser-based vibratory sensor

Science.gov (United States)

Nath, G.

2018-04-01

Sensor technology has proved its importance, not only in the range of few-meter applications in different fields, but in micro, nano, atomic and sub-atomic-sized objects. The present work describes the designing of a laser-based vibratory sensor using a He-Ne laser as the signal source. The received characteristics of the signal are mainly the frequency and amplitude of the vibration from which the physical parameters such as energy, power and absorption coefficients of the material are determined, which enables us to provide information of the hidden target or object. This laboratory-designed sensor finds application in different local phenomena as well as laboratory practical activity for students.

Modelling of Ne-like copper X-ray laser driven by 1.2 ps short pulse and 280 ps background pulse configuration

International Nuclear Information System (INIS)

Demir, A.; Kenar, N.; Goktas, H.; Tallents, G.J.

2004-01-01

Detailed simulations of Ne-like Cu x-ray laser are undertaken using the EHYBRID code. The atomic physics data are obtained using the Cowan code. The optimization calculations are performed in terms of the intensity of background and the time separation between the background and the short pulse. The optimum value is obtained for the conditions of a Nd:glass laser with 1.2 ps pulse at 4.4 x 10 15 W cm -2 irradiance pumping a plasma pre-formed by a 280 ps duration pulse at 5.4 x 10 12 W cm -2 with peak-to-peak pulse separation set at 300 ps. X-ray resonance lines between 6 A and 15 A emitted from copper plasmas have been simulated. Free-free and free-bound emission from the Si-, Al-, Mg-, Na-, Ne- and F-like ions is calculated in the simulation. (author)

A three-dimensional laser vibration measurement technology realized on five laser beam and its calibration

Science.gov (United States)

Li, Lu-Ke; Zhang, Shen-Feng

2018-03-01

Put forward a kind of three-dimensional vibration information technology of vibrating object by the mean of five laser beam of He-Ne laser, and with the help of three-way sensor, measure the three-dimensional laser vibration developed by above mentioned technology. The technology based on the Doppler principle of interference and signal demodulation technology, get the vibration information of the object, through the algorithm processing, extract the three-dimensional vibration information of space objects, and can achieve the function of angle calibration of five beam in the space, which avoid the effects of the mechanical installation error, greatly improve the accuracy of measurement. With the help of a & B K4527 contact three axis sensor, measure and calibrate three-dimensional laser vibrometer, which ensure the accuracy of the measurement data. Summarize the advantages and disadvantages of contact and non-contact sensor, and analysis the future development trends of the sensor industry.

Laser speckle velocimetry applied to Rayleigh-Benard convection

International Nuclear Information System (INIS)

Arroyo, M.P.; Yonte, T.; Quintanilla, M.; Saviron, J.M.

1986-01-01

An application of speckle velocimetry technique to Rayleigh-Benard convection is presented. A 5-mW He-Ne laser allows precise determination of the two-dimensional velocity flow field, up to several mm/sec. The digital techniques used to analyze automatically the multiexposed photographs and to generate velocity and vorticity fields are described. The obtained results are in good agreement with previously reported data. The ability of the technique to cover other experimental conditions is discussed. 14 references

Line overlap measurements for resonant photo-pumping of x-ray lasers

International Nuclear Information System (INIS)

Elliott, S.R.; Beiersdorfer, P.; Nilsen, J.

1993-01-01

Measurement taken on the LLNL EBIT to search for the possible photo-pumping of the 3p-3s lasing transitions in Ni-like ions of elements with Z=30--40 and the 4d-4p lasing transitions in Ne-like ions of elements with Z=47-73 are reported. A high-resolution crystral spectrometer was used to measure wavelengths of the Ne-like 2p-4d and the Ni-like 3d-5f and 3d-6f laser level feeding transitions relative to candidate pump lines in various H-, He-, and Ni-like ions. To date, the most promising candidate is Ni-like Pt pumping Ne-like Rb at 2512 eV. The line energies differ by 0.4±0.1 eV or by 160 ppm

Multiple Order Diffractions by laser-Injured Transient Grating in Nematic MBBA Film

International Nuclear Information System (INIS)

Kim, Seong Kyu; Kim, Hack Jin

1999-01-01

The laser-induced transient grating method is applied to study the dynamics of the nematic MBBA film. The nanosecond laser pulses of 355 nm are used to make the transient grating and the cw He-Ne laser of 633 nm is used to probe the dynamics. Strong multiple order diffractions are observed at high nematic temperatures. The reordering process induced by the phototransformed state, which is the locally melted state from the nematic sample, is attributed to the main origin of the multiple order diffractions from the nematic MBBA. The characteristics of the multiple order gratings are discussed with the grating profiles simulated from the multiple diffraction signals

Demonstration of a CW diode-pumped Ar metastable laser operating at 4  W.

Science.gov (United States)

Han, J; Heaven, M C; Moran, P J; Pitz, G A; Guild, E M; Sanderson, C R; Hokr, B

2017-11-15

Optically pumped rare gas lasers are being investigated as potential high-energy, high beam quality systems. The lasing medium consists of rare gas atoms (Rg=Ne, Ar, Kr, or Xe) that have been electric discharge excited to the metastable np 5 (n+1)s P3 2 state. Following optical excitation, helium (He) at pressures of 200-1000 Torr is used as the energy transfer agent to create a population inversion. The primary technical difficulty for this scheme is the discharge production of sufficient Rg* metastables in the presence of >200  Torr of He. In this Letter, we describe a pulsed discharge that yields >10 13   cm -3 Ar* in the presence of He at total pressures up to 750 Torr. Using this discharge, a diode-pumped Ar* laser providing 4.1 W has been demonstrated.

Effect of single-dose low-level helium-neon laser irradiation on orthodontic pain: a split-mouth single-blind placebo-controlled randomized clinical trial.

Science.gov (United States)

Sobouti, Farhad; Khatami, Maziar; Chiniforush, Nasim; Rakhshan, Vahid; Shariati, Mahsa

2015-01-01

Pain is the most common complication of orthodontic treatment. Low-level laser therapy (LLLT) has been suggested as a new analgesic treatment free of the adverse effects of analgesic medications. However, it is not studied thoroughly, and the available studies are quite controversial. Moreover, helium neon (He-Ne) laser has not been assessed before. This split-mouth placebo-controlled randomized clinical trial was performed on 16 male and 14 female orthodontic patients requiring bilateral upper canine retraction. The study was performed at a private clinic in Sari, Iran, in 2014. It was single blind: patients, orthodontist, and personnel were blinded of the allocations, but the laser operator (periodontist) was not blinded. Once canine retractor was activated, a randomly selected maxillary quarter received a single dose of He-Ne laser irradiation (632.8 nm, 10 mw, 6 j/cm(2) density). The other quarter served as the placebo side, treated by the same device but powered off. In the first, second, fourth, and seventh days, blinded patients rated their pain sensed on each side at home using visual analog scale (VAS) questionnaires. There was no harm identified during or after the study. Pain changes were analyzed using two- and one-way repeated-measures ANOVA, Bonferroni, and t-test (α = 0.01, β > 0.99). This trial was not registered. It was self-funded by the authors. Sixteen males and 11 females remained in the study (aged 12-21). Average pain scores sensed in all 4 intervals on control and laser sides were 4.06 ± 2.85 and 2.35 ± 1.77, respectively (t-test P < 0.0001). One-way ANOVA showed significant pain declines over time, in each group (P < 0.0001). Two-way ANOVA showed significant effects for LLLT (P < 0.0001) and time (P = <0.0001). Single-dose He-Ne laser therapy might reduce orthodontic pain caused by retracting maxillary canines.

Response of vegetable organisms to quasi-monochromatic light of different duration, intensity and wavelength

Energy Technology Data Exchange (ETDEWEB)

Budagovsky, A V; Solovykh, N V [I.V.Michurin All-Russian Recearch Institute of Fruit Crops Genetics and Breeding (Russian Federation); Budagovskaya, O N [I.V.Michurin All-Russia Research and Development Institute of Gardening, Michurinsk, Tambov region (Russian Federation); Budagovsky, I A [P N Lebedev Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation)

2015-04-30

By the example of vegetable organisms differing in structure and functional properties it is shown that their response to the action of quasi-monochromatic light from laser sources does not obey the Bunsen – Roscoe dose law. The dependence of biological effect on the irradiation time has the multimodal (multiextremal) form with alternating maxima and minima of the stimulating effect. Such a property manifests itself in the spectral ranges, corresponding to photoinduced conversion of chromoproteins of photocontrol systems and is probably related to the cyclic variations of metabolic activity in vegetable cells. (biophotonics)

Photoionization of Ne8+

Science.gov (United States)

Pindzola, M. S.; Abdel-Naby, Sh. A.; Robicheaux, F.; Colgan, J.

2014-05-01

Single and double photoionization cross sections for Ne8+ are calculated using a non-perturbative fully relativistic time-dependent close-coupling method. A Bessel function expansion is used to include both dipole and quadrupole effects in the radiation field interaction and the repulsive interaction between electrons includes both the Coulomb and Gaunt interactions. The fully correlated ground state of Ne8+ is obtained by solving a time-independent inhomogeneous set of close-coupled equations. Propagation of the time-dependent close-coupled equations yields single and double photoionization cross sections for Ne8+ at energies easily accessible at advanced free electron laser facilities. This work was supported in part by grants from NSF and US DoE. Computational work was carried out at NERSC in Oakland, California, NICS in Knoxville, Tennessee, and OLCF in Oak Ridge, Tennessee.

Mutation breeding of Bacillus subtilis YTB4 with high yield of ...

African Journals Online (AJOL)

DR TONUKARI NYEROVWO

2012-07-17

Jul 17, 2012 ... Helium-neon (He-Ne) laser irradiation is a highly efficient mutation breeding technology and is widely applied to various fields of biological science. Using Bacillus subtilis YTB4 with high yield of multienzyme complex as original strain, mutation breeding was carried out by He-Ne laser irradiation in.

Short distance line of sight laser communication

International Nuclear Information System (INIS)

Mudassar, A.A.; Hussain, H.; Jamil-ur-Rehman

1998-01-01

Communication methods based on lasers as carrier are well known. In our work we have made a two way laser based communication system for short range (<2 Km) line of sight communication. A small piece of plane mirror (100% reflector) was mounted on the centre of a speaker cone. The speaker was positioned close to the opening of laser such that He-Ne laser beam (10 mW) after reflection from the mirror is directed towards the receiver. There is a pre-amplifier and an amplifier between a microphone and the speaker. When the diagram of the speaker vibrates, it positionally modulates the laser beam. On the receiving end, there is a photo diode, a pre-amplifier, an amplifier and a head phone. So the man on the receiving end can decode the sound signal. On each stage there is a transmitter and a receiver assembled close to each other. So the two way communication is possible in the range 20 to 20 Khz. (author)

Soft X-ray laser using pumping of 3P and 4P levels of He-like and H-like ions

Science.gov (United States)

Hagelstein, P.L.

1987-04-21

X-ray laser method and apparatus are disclosed for producing coherent radiation at, for example, energies of at least 40 eV, using Be-like Cr, N-like Ni, He-like Na, B-like Cr, Be-like Mn or similar multiply ionized species to pump appropriate high energy transitions in He-like or H-like N, O, F, C or rare gases, with associated laser transition gains of 4-50 cm[sup [minus]1]. 8 figs.

Static electric polarizabilities and first hyperpolarizabilities of molecular ions RgH + (Rg = He, Ne, Ar, Kr, Xe): ab initio study

Science.gov (United States)

Cukras, Janusz; Antušek, Andrej; Holka, Filip; Sadlej, Joanna

2009-06-01

Extensive ab initio calculations of static electric properties of molecular ions of general formula RgH + (Rg = He, Ne, Ar, Kr, Xe) involving the finite field method and coupled cluster CCSD(T) approach have been done. The relativistic effects were taken into account by Douglas-Kroll-Hess approximation. The numerical stability and reliability of calculated values have been tested using the systematic sequence of Dunning's cc-pVXZ-DK and ANO-RCC-VQZP basis sets. The influence of ZPE and pure vibrational contribution has been discussed. The component αzz has increasing trend in RgH + while the relativistic effect on αzz leads to a small increase of this molecular parameter.

Study of 19F and 19Ne mirror nuclei

International Nuclear Information System (INIS)

Lebrun, Claude.

1976-01-01

The electromagnetic properties of the mirror nuclei 19 F and 19 Ne were studied using the 18 O(d,nγ) 19 F, 17 O( 3 He,nγ) 19 Ne and 19 F(p,nγ) 19 Ne reactions. Lifetimes of 8 levels in 19 F and 11 levels in 19 Ne have been measured using the Doppler shift attenuation method. Weak and strong components of M 1 , E 1 and E 2 transition strengths are compared with shell model predictions. M 1 and E 2 transition strengths of conjugated nuclei (A=18 to A=34) are compiled and compared with wide configuration space shell models [fr

Information content in spectral dependencies of optical unit volume parameters under action of He-Ne laser on blood

Science.gov (United States)

Khairullina, Alphiya Y.; Oleinik, Tatiana V.

1995-01-01

Our previous works concerned with the development of methods for studying blood and action of low-intensity laser radiation on blood and erythrocyte suspensions had shown the light- scattering methods gave a large body of information on a medium studied due to the methodological relationship between irradiation processes and techniques for investigations. Detail analysis of spectral diffuse reflectivities and transmissivities of optically thick blood layers, spectral absorptivities calculated on this basis over 600 - 900 nm, by using different approximations, for a pathological state owing to hypoxia testifies to the optical significance of not only hemoglobin derivatives but also products of hemoglobin decomposition. Laser action on blood is specific and related to an initial state of blood absorption due to different composition of chromoproteids. This work gives the interpretation of spectral observations. Analysis of spectral dependencies of the exinction coefficient e, mean cosine m of phase function, and parameter Q equals (epsilon) (1-(mu) )H/(lambda) (H - hematocrit) testifies to decreasing the relative index of refraction of erythrocytes and to morphological changes during laser action under pathology owing to hypoxia. The possibility to obtain physical and chemical information on the state of blood under laser action in vivo is shown to be based on the method proposed by us for calculating multilayered structures modeling human organs and on the technical implementation of this method.

A laser optical method for detecting corn kernel defects

Energy Technology Data Exchange (ETDEWEB)

Gunasekaran, S.; Paulsen, M. R.; Shove, G. C.

1984-01-01

An opto-electronic instrument was developed to examine individual corn kernels and detect various kernel defects according to reflectance differences. A low power helium-neon (He-Ne) laser (632.8 nm, red light) was used as the light source in the instrument. Reflectance from good and defective parts of corn kernel surfaces differed by approximately 40%. Broken, chipped, and starch-cracked kernels were detected with nearly 100% accuracy; while surface-split kernels were detected with about 80% accuracy. (author)

Biphotonic holographic gratings in azobenzene polyesters: Surface relief phenomena and polarization effects

DEFF Research Database (Denmark)

Sánchez, C.; Alcalá, R.; Hvilsted, Søren

2000-01-01

Biphotonic holographic gratings have been recorded in a side-chain azobenzene liquid crystalline polyester using a blue incoherent source and a He-Ne laser. Intensity gratings and the appearance of surface relief have been observed when two linearly polarized beams from a He-Ne laser are made...... to interfere on a film illuminated with blue light. Polarized holographic gratings are also created with two orthogonally circularly polarized He-Ne beams. All these gratings are stable in darkness but can be erased with blue light. (C) 2000 American Institute of Physics....

The cryogenic source of slow monochromatic positrons

International Nuclear Information System (INIS)

Meshkov, I.N.; Pavlov, V.N.; Sidorin, A.O.; Yakovenko, S.L.

2008-01-01

The cryogenic source of slow monochromatic positrons based on the 22 Na isotope has been designed and constructed at JINR. Positrons emitted from radioactive source 22 Na have a very broad energy spectrum up to 0.5 MeV. To generate monochromatic beam of slow positrons the solid neon is used as a moderator. The solid neon allows forming slow positron beam of the energy of 1.2 eV at the spectrum width of 1 eV. The efficiency of moderation is 1 % of total positron flux

Effects of the Lexington LaserComb on hair regrowth in the C3H/HeJ mouse model of alopecia areata.

Science.gov (United States)

Wikramanayake, Tongyu Cao; Rodriguez, Rosa; Choudhary, Sonal; Mauro, Lucia M; Nouri, Keyvan; Schachner, Lawrence A; Jimenez, Joaquin J

2012-03-01

Alopecia areata (AA) is a common autoimmune disease that presents with non-scarring alopecia. It is characterized by intra- or peri-follicular lymphocytic infiltrates composed of CD4+ and CD8+ T-cells on histology. To this day, few treatments are effective for AA. Here we present findings of using a low-level laser comb to alleviate the symptoms of AA in a C3H/HeJ mouse model for AA. Fourteen C3H/HeJ mice with induced AA were used in this study. Two were killed to confirm AA through histology. The remaining 12 mice were randomized into two groups; group I received HairMax LaserComb (wavelength: 655 nm, beam diameter lasers) for 20 s daily, three times per week for a total of 6 weeks; group II was treated similarly, except that the laser was turned off (sham-treated). After 6 weeks of LaserComb treatment, hair regrowth was observed in all the mice in group I (laser-treated) but none in group II (sham-treated). On histology, increased number of anagen hair follicles was observed in laser-treated mice. On the other hand, sham-treated mice demonstrated hair follicles in the telogen phase with no hair shaft. LaserComb seems to be an effective and convenient device for the treatment of AA in the C3H/HeJ mouse model. Human studies are required to determine the efficacy and safety of this device for AA therapy.

Laser-induced charge transfer in the HeH2+ quasimolecule

International Nuclear Information System (INIS)

Errea, L.F.; Mendez, L.; Riera, A.

1983-01-01

In a recent publication, the charge transfer cross section for He 2+ +H(ls) collisions through photon-assisted 2psigma--3dsigma transitions was calculated; this calculation, however, contained several errors whose quantitative--even qualitative effect on the results is not obvious. We present a correct evaluation of this laser-induced cross section, which turns out to be larger, and present a maximum for longer wavelengths, than the values previously reported. In addition, we have checked the applicability of perturbation theory, of the stationary phase, uniform and Landau--Zener approximations, and the importance of potentially competitive photon-assisted reactions

Determination of the absolute two-photon ionization cross section of He by an XUV free electron laser

International Nuclear Information System (INIS)

Sato, Takahiro; Iwasaki, Atsushi; Ishibashi, Kazuki; Okino, Tomoya; Yamanouchi, Kaoru; Adachi, Junichi; Yagishita, Akira; Yazawa, Hiroki; Aoyma, Makoto; Yabashi, Makina; Nagasono, Mitsuru; Higashiya, Atsushi; Ishikawa, Tetsuya; Kannari, Fumihiko; Yamakawa, Koichi; Midorikawa, Katsumi; Nakano, Hidetoshi

2011-01-01

The resonant and non-resonant two-photon single ionization processes of He were investigated using intense free electron laser light in the extreme ultraviolet (XUV) region (53.4-61.4 nm) covering the 1s-2p and 1s-3p resonant transitions of He. On the basis of the dependences of the yield of He + on the XUV light-field intensity at 53.4, 58.4, 56.0 and 61.4 nm, the absolute values of the two-photon ionization cross sections of He at the four different wavelengths and their dependence on the light-field intensity were determined for the first time. (fast track communication)

Mutation breeding of Bacillus subtilis YTB4 with high yield of ...

African Journals Online (AJOL)

Helium-neon (He-Ne) laser irradiation is a highly efficient mutation breeding technology and is widely applied to various fields of biological science. Using Bacillus subtilis YTB4 with high yield of multienzyme complex as original strain, mutation breeding was carried out by He-Ne laser irradiation in this study. Based on the ...

The clinical effects observation of He-Ne laser combined with dryness itching capsules for treating herpes zoster%氦氖激光联合润燥止痒胶囊治疗带状疱疹的临床疗效观察

Institute of Scientific and Technical Information of China (English)

聂丽; 单玉珍

2015-01-01

Objective To investigate the clinical effects of He-Ne laser combined with dryness itching capsules for treating herpes zoster.Methods 140 patients with herpes zoster based on the random lottery principle were equally divided into the treatment group of 70 patients and 70 patients in the control group.140 patients were given the acyclovir oral and helium-neon laser therapy,on the basis of these,the treatment group were added treated with oral dryness itching capsules therapy.Results The response rate was 98.6％ in the treatment group and 90.0％ in the control group.The response rate of the treatment group was significantly higher (P ＜ 0.05) than that of the control group.The pain scores before treatment was not statistically significant between the two groups while the pain scores of the treatment group after treatment were significantly lower than the control group (P ＜ 0.05).The analgesic immediately onset time,crusting time and pain began to ease time of the treatment group were significantly less than the control group (P ＜ 0.05).Followed-up eight weeks after treatment,the recurrence rate in the treatment group was 4.3％ and 20.0％ in the control group,the recurrence rate in the treatment group was significantly lower than the control group (P ＜ 0.05).Conclusions He-Ne laser combined with itching dryness capsule in the treatment of herpes zoster can effectively relieve pain,improve clinical symptoms,thus improve the overall efficacy and recurrence rate that should be widely applied.%目的 探讨氦氖激光联合润燥止痒胶囊治疗带状疱疹的临床疗效.方法 根据随机抽签原则,将带状疱疹患者140例分为治疗组70例与对照组70例,两组都选择阿昔洛韦口服与氦氖激光治疗,治疗组在此基础上加用口服润燥止痒胶囊治疗,都治疗14天.结果 治疗组的有效率为98.6％,对照组的有效率为90.0％,治疗组的有效率经明显高于对照组(P＜0.05).�

Quantitative and sensitive analysis of CN molecules using laser induced low pressure He plasma

Energy Technology Data Exchange (ETDEWEB)

Pardede, Marincan [Department of Electrical Engineering, University of Pelita Harapan, 1100 M.H. Thamrin Boulevard, Lippo Village, Tangerang 15811 (Indonesia); Hedwig, Rinda [Department of Computer Engineering, Bina Nusantara University, 9 K.H. Syahdan, Jakarta 14810 (Indonesia); Abdulmadjid, Syahrun Nur; Lahna, Kurnia; Idris, Nasrullah; Ramli, Muliadi [Department of Physics, Faculty of Mathematics and Natural Sciences, Syiah Kuala University, Darussalam, Banda Aceh 23111, NAD (Indonesia); Jobiliong, Eric [Department of Industrial Engineering, University of Pelita Harapan, 1100 M.H. Thamrin Boulevard, Lippo Village, Tangerang 15811 (Indonesia); Suyanto, Hery [Department of Physics, Faculty of Mathematics and Natural Sciences, Udayana University, Kampus Bukit Jimbaran, Denpasar 80361, Bali (Indonesia); Marpaung, Alion Mangasi [Department of Physics, Faculty of Mathematics and Natural Sciences, Jakarta State University, 10 Rawamangun, Jakarta 13220 (Indonesia); Suliyanti, Maria Margaretha [Research Center for Physics, Indonesia Institute of Sciences, Kawasan Puspiptek, Serpong, Tangerang Selatan, 15314 Banten (Indonesia); Tjia, May On [Physics of Magnetism and Photonics Group, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, 10 Ganesha, Bandung 40132 (Indonesia); Research Center of Maju Makmur Mandiri Foundation, 40/80 Srengseng Raya, Jakarta 11630 (Indonesia); Lie, Tjung Jie; Lie, Zener Sukra; Kurniawan, Davy Putra; Kurniawan, Koo Hendrik, E-mail: kurnia18@cbn.net.id [Research Center of Maju Makmur Mandiri Foundation, 40/80 Srengseng Raya, Jakarta 11630 (Indonesia); Kagawa, Kiichiro [Research Center of Maju Makmur Mandiri Foundation, 40/80 Srengseng Raya, Jakarta 11630 (Indonesia); Fukui Science Education Academy, Takagi Chuou 2 choume, Fukui 910-0804 (Japan)

2015-03-21

We report the results of experimental study on CN 388.3 nm and C I 247.8 nm emission characteristics using 40 mJ laser irradiation with He and N{sub 2} ambient gases. The results obtained with N{sub 2} ambient gas show undesirable interference effect between the native CN emission and the emission of CN molecules arising from the recombination of native C ablated from the sample with the N dissociated from the ambient gas. This problem is overcome by the use of He ambient gas at low pressure of 2 kPa, which also offers the additional advantages of cleaner and stronger emission lines. The result of applying this favorable experimental condition to emission spectrochemical measurement of milk sample having various protein concentrations is shown to yield a close to linear calibration curve with near zero extrapolated intercept. Additionally, a low detection limit of 5 μg/g is found in this experiment, making it potentially applicable for quantitative and sensitive CN analysis. The visibility of laser induced breakdown spectroscopy with low pressure He gas is also demonstrated by the result of its application to spectrochemical analysis of fossil samples. Furthermore, with the use of CO{sub 2} ambient gas at 600 Pa mimicking the Mars atmosphere, this technique also shows promising applications to exploration in Mars.

Comment on “Collision monochromatization in e^{+}e^{-} colliders”

Directory of Open Access Journals (Sweden)

D. Shatilov

2018-02-01

Full Text Available Bogomyagkov and Levichev [Phys. Rev. Accel. Beams 20, 051001 (2017PRABCJ2469-988810.1103/PhysRevAccelBeams.20.051001] have recently reported on monochromatization in collision schemes with crossing angle. From their results, in particular, it may seem that: (1 horizontal dispersion at the IP can provide monochromatization factor Λ≫1 while retaining Piwinski angle ϕ>1, (2 production rate in such a scheme for FCC-ee at 62.5 GeV can be larger than that in the nominal crab waist collision, and (3 strong rf focusing can be used for monochromatization purposes. We demonstrate here that the first two statements are not correct, and the last one is very doubtful.

Color Laser Microscope

Science.gov (United States)

Awamura, D.; Ode, T.; Yonezawa, M.

1987-04-01

A color laser microscope utilizing a new color laser imaging system has been developed for the visual inspection of semiconductors. The light source, produced by three lasers (Red; He-Ne, Green; Ar, Blue; He-Cd), is deflected horizontally by an AOD (Acoustic Optical Deflector) and vertically by a vibration mirror. The laser beam is focused in a small spot which is scanned over the sample at high speed. The light reflected back from the sample is reformed to contain linear information by returning to the original vibration mirror. The linear light is guided to the CCD image sensor where it is converted into a video signal. Individual CCD image sensors are used for each of the three R, G, or B color image signals. The confocal optical system with its laser light source yields a color TV monitor image with no flaring and a much sharper resolution than that of the conventional optical microscope. The AOD makes possible a high speed laser scan and a NTSC or PAL TV video signal is produced in real time without any video memory. Since the light source is composed of R, G, and B laser beams, color separation superior to that of white light illumination is achieved. Because of the photometric linearity of the image detector, the R, G, and B outputs of the system are most suitably used for hue analysis. The CCD linear image sensors in the optical system produce no geometrical distortion, and good color registration is available principally. The output signal can be used for high accuracy line width measuring. The many features of the color laser microscope make it ideally suited for the visual inspection of semiconductor processing. A number of these systems have already been installed in such a capacity. The Color Laser Microscope can also be a very useful tool for the fields of material engineering and biotechnology.

Variations of 3/He/4He isotope ratios within the Broadlands geothermal field, New Zealand

International Nuclear Information System (INIS)

Hulston, John; Lupton, John; University of California, Santa Barbara; Rosenberg, Nina

1986-01-01

The Broadlands-Ohaaki geothermal field is located 20 km NE of Wairakei on the Central Volcanic Zone of New Zealand. It falls within a resistivity low extending 4 km by 3 km. A study of 3 He/ 4 He ratios within this field has shown R/R A ratios close to 6.0 in the Ohaaki production area (NW). In contrast the production area to the SE on the east bank of the Waikato River has R/R A values close to 3.5. Differences in chemical ratios reported previously are found to correlate with the 3 He/ 4 He measurements. A tentative interpretation of the results indicate that there is a contribution of 3 He from the mantle and that the variations in the 3 He/ 4 He ratios are probably related to differences in the geochemistry of the rocks through which the geothermal fluids flow to the surface. Preliminary measurements of the argon isotopes also show a contribution from radiogenic rocks at depth

Photobiomodulation by helium neon and diode lasers in an excisional wound model: A single blinded trial

Directory of Open Access Journals (Sweden)

Snehil Dixit

2012-01-01

Full Text Available Background: Application of different kinds of lasers in clinical and experimental studies causes photobiomodulation that works at localized cellular and humoral level on various biological systems. Increased numbers of fibroblasts, myofibroblast, and degranulation of mast cells have been the observed benefits post-irradiation. Objective: Was to find out the effect of irradiation with energy densities of 3.38 J/cm 2 , 8 J/cm 2 , and 18 J/cm 2 on animal tissue (albino wistar rats in an excisional wound model and to assess changes in biochemical (hydroxyproline and histopathological levels in excisional wound model. Materials and Methods: The animals were divided into 4 groups, which were labeled as L1, diode laser (18 J/cm 2 , L2 Helium-neon (He-Ne, 8 J/cm 2 , L3 diode laser (3.38 J/cm 2 , and sham treatment for control was depicted by C, respectively. Histological and hydroxyproline analysis was performed on 7, 14, 21 days of post-wounding. One-way analysis of variance, ANOVA and Bonferroni′s multiple comparison tests were done for tissue hydroxyproline levels. Results: There was no significant increase in the hydroxyproline content (P < 0.005 when observed in study group and compared to controls. Whereas significant epithelizations was seen in group treated with He-Ne laser of intensity of 8 J/cm 2 . Conclusion: The experimental observations suggest that low intensity helium-neon laser of 8 J/cm 2 intensity facilitated photo stimulation by tissue repair, but failed to show significant tissue hydroxyproline levels in excisional wound model.

A mirror for lab-based quasi-monochromatic parallel x-rays.

Science.gov (United States)

Nguyen, Thanhhai; Lu, Xun; Lee, Chang Jun; Jung, Jin-Ho; Jin, Gye-Hwan; Kim, Sung Youb; Jeon, Insu

2014-09-01

A multilayered parabolic mirror with six W/Al bilayers was designed and fabricated to generate monochromatic parallel x-rays using a lab-based x-ray source. Using this mirror, curved bright bands were obtained in x-ray images as reflected x-rays. The parallelism of the reflected x-rays was investigated using the shape of the bands. The intensity and monochromatic characteristics of the reflected x-rays were evaluated through measurements of the x-ray spectra in the band. High intensity, nearly monochromatic, and parallel x-rays, which can be used for high resolution x-ray microscopes and local radiation therapy systems, were obtained.

Photoelectric-enhanced radiation therapy with quasi-monochromatic computed tomography

International Nuclear Information System (INIS)

Jost, Gregor; Mensing, Tristan; Golfier, Sven; Lawaczeck, Ruediger; Pietsch, Hubertus; Huetter, Joachim; Cibik, Levent; Gerlach, Martin; Krumrey, Michael; Fratzscher, Daniel; Arkadiev, Vladimir; Wedell, Reiner; Haschke, Michael; Langhoff, Norbert; Wust, Peter; Luedemann, Lutz

2009-01-01

Photoelectric-enhanced radiation therapy is a bimodal therapy, consisting of the administration of highly radiation-absorbing substances into the tumor area and localized regional irradiation with orthovoltage x-rays. Irradiation can be performed by a modified computed tomography (CT) unit equipped with an additional x-ray optical module which converts the polychromatic, fan-shaped CT beam into a monochromatized and focused beam for energy-tuned photoelectric-enhanced radiotherapy. A dedicated x-ray optical module designed for spatial collimation, focusing, and monochromatization was mounted at the exit of the x-ray tube of a clinical CT unit. Spectrally resolved measurements of the resulting beam were performed using an energy-dispersive detection system calibrated by synchrotron radiation. The spatial photon fluence was determined by film dosimetry. Depth-dose measurements were performed and compared to the polychromatic CT and a therapeutic 6 MV beam. The spatial dose distribution in phantoms using a rotating radiation source (quasi-monochromatic CT and 6 MV, respectively) was investigated by gel dosimetry. The photoelectric dose enhancement for an iodine fraction of 1% in tissue was calculated and verified experimentally. The x-ray optical module selectively filters the energy of the tungsten Kα emission line with an FWHM of 5 keV. The relative photon fluence distribution demonstrates the focusing characteristic of the x-ray optical module. A beam width of about 3 mm was determined at the isocenter of the CT gantry. The depth-dose measurements resulted in a half-depth value of approximately 36 mm for the CT beams (quasi-monochromatic, polychromatic) compared to 154 mm for the 6 MV beam. The rotation of the radiation source leads to a steep dose gradient at the center of rotation; the gel dosimetry yields an entrance-to-peak dose ratio of 1:10.8 for the quasi-monochromatic CT and 1:37.3 for a 6 MV beam of the same size. The photoelectric dose enhancement factor

Photoelectric-enhanced radiation therapy with quasi-monochromatic computed tomography

Energy Technology Data Exchange (ETDEWEB)

Jost, Gregor; Mensing, Tristan; Golfier, Sven; Lawaczeck, Ruediger; Pietsch, Hubertus; Huetter, Joachim; Cibik, Levent; Gerlach, Martin; Krumrey, Michael; Fratzscher, Daniel; Arkadiev, Vladimir; Wedell, Reiner; Haschke, Michael; Langhoff, Norbert; Wust, Peter; Luedemann, Lutz [TRG Diagnostic Imaging, Bayer Schering Pharma AG, 13353 Berlin (Germany); Department of Radiotherapy, Charite Medical Centre, 13353 Berlin (Germany); TRG Diagnostic Imaging, Bayer Schering Pharma AG, 13353 Berlin (Germany); Physikalisch-Technische Bundesanstalt, 10587 Berlin (Germany); Institute of Applied Photonics e.V., 12489 Berlin (Germany); Institute for Scientific Instruments GmbH, 12489 Berlin (Germany); Department of Radiotherapy, Charite Medical Centre, 13353 Berlin (Germany)

2009-06-15

Photoelectric-enhanced radiation therapy is a bimodal therapy, consisting of the administration of highly radiation-absorbing substances into the tumor area and localized regional irradiation with orthovoltage x-rays. Irradiation can be performed by a modified computed tomography (CT) unit equipped with an additional x-ray optical module which converts the polychromatic, fan-shaped CT beam into a monochromatized and focused beam for energy-tuned photoelectric-enhanced radiotherapy. A dedicated x-ray optical module designed for spatial collimation, focusing, and monochromatization was mounted at the exit of the x-ray tube of a clinical CT unit. Spectrally resolved measurements of the resulting beam were performed using an energy-dispersive detection system calibrated by synchrotron radiation. The spatial photon fluence was determined by film dosimetry. Depth-dose measurements were performed and compared to the polychromatic CT and a therapeutic 6 MV beam. The spatial dose distribution in phantoms using a rotating radiation source (quasi-monochromatic CT and 6 MV, respectively) was investigated by gel dosimetry. The photoelectric dose enhancement for an iodine fraction of 1% in tissue was calculated and verified experimentally. The x-ray optical module selectively filters the energy of the tungsten K{alpha} emission line with an FWHM of 5 keV. The relative photon fluence distribution demonstrates the focusing characteristic of the x-ray optical module. A beam width of about 3 mm was determined at the isocenter of the CT gantry. The depth-dose measurements resulted in a half-depth value of approximately 36 mm for the CT beams (quasi-monochromatic, polychromatic) compared to 154 mm for the 6 MV beam. The rotation of the radiation source leads to a steep dose gradient at the center of rotation; the gel dosimetry yields an entrance-to-peak dose ratio of 1:10.8 for the quasi-monochromatic CT and 1:37.3 for a 6 MV beam of the same size. The photoelectric dose enhancement

[Theory of lasers and lamps].

Science.gov (United States)

Mordon, S; Michaud, T

2009-10-01

Lasers emit a coherent and monochromatic light beam, whereas pulsed lights produce a polychromatic light whose bandwidth is selected by adapted filters. The skin's chromophores are made up of water, hemoglobin, and melanin, to which must be added the exogenous pigments of tattoos. Each chromophore has its specific absorption spectrum. Lasers' main mechanisms of action are the photothermal effect and the photomechanical effect.

Laser interferometer array for Big Dee

International Nuclear Information System (INIS)

Fairbanks, E.S.

1984-01-01

A twelve channel interferometer array is planned for obtaining electron density profiles on Big Dee. Three of the channels are vertical; the remainder are radial or diagonal in an azimuthal plane. Each channel consists of coaxial CO/sub 2/ and HeNe laser beams. The reference beam is formed by splitting off half of the laser power at each wavelength by using acousto-optic modulators which introduce a 40 MHz frequency shift in the reference beam. In the radial channels the probe beam passes through a barium fluoride window to a plane metal mirror on the inside wall of the vacuum vessel. The reflected beam passes back out of the vacuum vessel, through the same window, to a beam splitter where the probe beam and the reference beam are again combined

Laser illuminated flat panel display

Energy Technology Data Exchange (ETDEWEB)

Veligdan, J.T.

1995-12-31

A 10 inch laser illuminated flat panel Planar Optic Display (POD) screen has been constructed and tested. This POD screen technology is an entirely new concept in display technology. Although the initial display is flat and made of glass, this technology lends itself to applications where a plastic display might be wrapped around the viewer. The display screen is comprised of hundreds of planar optical waveguides where each glass waveguide represents a vertical line of resolution. A black cladding layer, having a lower index of refraction, is placed between each waveguide layer. Since the cladding makes the screen surface black, the contrast is high. The prototype display is 9 inches wide by 5 inches high and approximately I inch thick. A 3 milliwatt HeNe laser is used as the illumination source and a vector scanning technique is employed.

A versatile lattice for a tau-charm factory that includes a monochromatization scheme

International Nuclear Information System (INIS)

Faus-Golfe, A.; Le Duff, J.

1992-02-01

A double ring system with multibunch scheme and high luminosity is discussed. An attempt for beam monochromatization at the crossing point was made by increasing the vertical bending angle, and it succeeded in providing a proper matching. The next step consisted of demonstrating that the new ring geometry that permits a monochromatization scheme could be returned and rematched to operate without monochromatization, allowing only relocation of quadrupoles and readjustment of their gradient in the sloping region. The results of this work are reported after a brief recall of the monochromatization scheme requirements. (K.A.) 10 refs., 13 figs., 2 tabs

Laser-induced charge transfer in the HeH/sup 2 +/ quasimolecule

Energy Technology Data Exchange (ETDEWEB)

Errea, L.F.; Mendez, L.; Riera, A.

1983-11-01

In a recent publication, the charge transfer cross section for He/sup 2 +/+H(ls) collisions through photon-assisted 2psigma--3dsigma transitions was calculated; this calculation, however, contained several errors whose quantitative--even qualitative effect on the results is not obvious. We present a correct evaluation of this laser-induced cross section, which turns out to be larger, and present a maximum for longer wavelengths, than the values previously reported. In addition, we have checked the applicability of perturbation theory, of the stationary phase, uniform and Landau--Zener approximations, and the importance of potentially competitive photon-assisted reactions.

Plasma density evolution in plasma opening switch obtained by a time-resolved sensitive He-Ne interferometer

Science.gov (United States)

Chen, Lin; Ren, Jing; Guo, Fan; Zhou, LiangJi; Li, Ye; He, An; Jiang, Wei

2014-03-01

To understand the formation process of vacuum gap in coaxial microsecond conduction time plasma opening switch (POS), we have made measurements of the line-integrated plasma density during switch operation using a time-resolved sensitive He-Ne interferometer. The conduction current and conduction time in experiments are about 120 kA and 1 μs, respectively. As a result, more than 85% of conduction current has been transferred to an inductive load with rise time of 130 ns. The radial dependence of the density is measured by changing the radial location of the line-of-sight for shots with the same nominal POS parameters. During the conduction phase, the line-integrated plasma density in POS increases at all radial locations over the gun-only case by further ionization of material injected from the guns. The current conduction is observed to cause a radial redistribution of the switch plasma. A vacuum gap forms rapidly in the plasma at 5.5 mm from the center conductor, which is consistent with the location where magnetic pressure is the largest, allowing current to be transferred from the POS to the load.

Beam experiments with state selected Ne (3P0, 3P2) metastable atoms

International Nuclear Information System (INIS)

Verheijen, M.J.

1984-01-01

Metastable rare gas atoms play an important role in all types of plasmas and gas discharges, e.g. in fluorescent lamps and in laser discharges (helium-neon laser or excimer lasers). In this thesis, the metastable states of NeI are studied. First, the theory of excited neon atoms and diatomic molecules is introduced, as well as Penning ionisation. Next, some experimental facilities are described (e.g. the dye laser system). With these instruments, natural lifetime measurements of the 2p fine structure states of NeI are carried out. Results are reported. Finally, total Penning ionisation cross sections are calculated using the optical potential model. (Auth.)

Using laser to measure stem thickness and cut weed stems

DEFF Research Database (Denmark)

Heisel, T.; Schou, Jørgen; Andreasen, C.

2002-01-01

Stem thickness of the weed Solanum nigrum and the crop sugarbeet was determined with a He-Ne laser using a novel non-destructive technique measuring stem shadow. Thereafter, the stems were cut close to the soil surface with a CO2 laser. Treatments were carried out on pot plants, grown....... A binary model was also tested. The non-linear model incorporating stem thickness described the data best, indicating that it would be possible to optimize laser cutting by measuring stem thickness before cutting. The general tendency was that more energy was needed the thicker the stem. Energy uses...... in the greenhouse, at two different growth stages, and plant dry matter was measured 2-5 weeks after treatment. The relationship between plant dry weight and laser energy was analysed using two different non-linear dose-response regression models; one model included stem thickness as a variable, the other did not...

Analysis on the electron motion in the laser mixture CO/sub 2/-N/sub 2/-He-CO

Energy Technology Data Exchange (ETDEWEB)

Braglia, G L [Parma Univ. (Italy). Ist. di Fisica; Parma Univ. (Italy). Ist. di Matematica); Bruzzese, R [Naples Univ. (Italy). Ist. Elettrotecnico; Caraffini, G L [Parma Univ. (Italy). Ist. di Matematica

1979-06-02

An analysis of the electron motion in the laser mixture CO/sub 2/-N/sub 2/-He-CO (6:34:54:6) is presented. The transport coefficients are given as a function of E/N. Special attention is turned to the operating characteristics of the laser mixture. The results obtained from the Boltzmann equation are tested by the Monte-Carlo technique for E/N=1.5 10/sup -16/ and 5.0 10/sup -16/ (V cm/sup 2/).

Optimizing Monochromatic Focusing on ThALES

Czech Academy of Sciences Publication Activity Database

Čermák, P.; Boehm, M.; Kulda, J.; Roux, S.; Hiess, A.; Steffens, P.; Šaroun, Jan

2014-01-01

Roč. 82, A (2014), SA026 ISSN 0031-9015 Institutional support: RVO:61389005 Keywords : Monte Carlo ray-tracing * inelastic neutron scattering * Triple-Axis spectrometer * monochromatic focusing Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.585, year: 2014

X-ray absorption spectroscopy in the keV range with laser generated high harmonic radiation

International Nuclear Information System (INIS)

Seres, Enikoe; Seres, Jozsef; Spielmann, Christian

2006-01-01

By irradiating He and Ne atoms with 3 mJ, 12 fs, near infrared laser pulses from a tabletop laser system, the authors generated spatially and temporally coherent x rays up to a photon energy of 3.5 keV. With this source it is possible to use high-harmonic radiation for x-ray absorption spectroscopy in the keV range. They were able to clearly resolve the L absorption edges of titanium and copper and the K edges of aluminum and silicon. From the fine structure of the x-ray absorption they estimated the interatomic distances

Color speckle in laser displays

Science.gov (United States)

Kuroda, Kazuo

2015-07-01

At the beginning of this century, lighting technology has been shifted from discharge lamps, fluorescent lamps and electric bulbs to solid-state lighting. Current solid-state lighting is based on the light emitting diodes (LED) technology, but the laser lighting technology is developing rapidly, such as, laser cinema projectors, laser TVs, laser head-up displays, laser head mounted displays, and laser headlamps for motor vehicles. One of the main issues of laser displays is the reduction of speckle noise1). For the monochromatic laser light, speckle is random interference pattern on the image plane (retina for human observer). For laser displays, RGB (red-green-blue) lasers form speckle patterns independently, which results in random distribution of chromaticity, called color speckle2).

Monochromatic and identifiable photons used in photonuclear research

International Nuclear Information System (INIS)

Beil, Hans; Bergere, Roland.

1980-07-01

A general overview is given of the most common experimental procedures for the production and utilisation of monochromatic and (or) identifiable photon probes actually operational in 1979. Their basic characteristics, merits and drawbacks, together with their respective major domains of experimental physics to which they are usually applied, are also investigated. Methods for producing such monochromatic and (or) identifiable photon probes, with a continuously variable energy from a few MeV up till about 180 GeV, are treated in some detail. Some of the most promising future trends in the ulterior development of such electromagnetic probes are also mentioned

Modeling bidirectionally coupled single-mode semiconductor lasers

International Nuclear Information System (INIS)

Mulet, Josep; Masoller, Cristina; Mirasso, Claudio R.

2002-01-01

We develop a dynamical model suitable for the description of two mutually coupled semiconductor lasers in a face-to-face configuration. Our study considers the propagation of the electric field along the compound system as well as the evolution of the carrier densities within each semiconductor laser. Mutual injection, passive optical feedback, and multiple reflections are accounted for in this framework, although under weak to moderate coupling conditions. We systematically describe the effect of the coupling strength on the spectrum of monochromatic solutions and on the respective dynamical behavior. By assuming single-longitudinal-mode operation, weak mutual coupling and slowly varying approximation, the dynamical model can be reduced to rate equations describing the mutual injection from one laser to its counterpart and vice versa. A good agreement between the complete and simplified models is found for small coupling. For larger coupling, higher-order terms lead to a smaller threshold reduction, reflected itself in the spectrum of the monochromatic solutions and in the dynamics of the optical power

Particle densities in a positive column He-I+ discharge

International Nuclear Information System (INIS)

Gato, T.

1980-01-01

In a positive column He-1 + laser discharge, the He + ion density has been determined directly from the absorption of the HeII 30.3 nm resonance line measured by a modified absorption method, and the electron density has been obtained using this measured He + ion density. The population densities of the upper and lower states of the 612.7 nm laser line have also been measured roughly. (orig.)

Influence of CdS nanoparticles grain morphology on laser-induced absorption

Science.gov (United States)

Ebothé, Jean; Michel, Jean; Kityk, I. V.; Lakshminarayana, G.; Yanchuk, O. M.; Marchuk, O. V.

2018-06-01

Using external illumination of a 7 nanosecond (ns) doubled frequency Nd: YAG laser emitting at λ = 532 nm with frequency repetition 10 Hz it was established a possibility of significant changes of the absorption at the probing wavelength 1150 nm of continuous wave (cw) He-Ne laser for the CdS nanoparticles embedded into the PVA polymer matrix. The effect is observed only during the two beam laser coherent treatment and this effect is a consequence of interference of two coherent beams. It is shown a principal role of the grain morphology in the efficiency of the process, which is more important than the nanoparticle sizes. The photoinduced absorption is manifested in the space distribution of the probing laser beam. The principal role of the grain interfaces between the nanoparticle interfaces and the surrounding polymer matrix is shown. The effect is almost independent of the nanoparticle sizes. It may be used for laser operation by nanocomposites.

An estimation of the spatial coherency radius of a multimode laser beam by the spectral contrast

Energy Technology Data Exchange (ETDEWEB)

Sukhanov, I I

1983-01-01

The angular dependency of the spectral contrast behind a diffuser illuminated by an He/Ne laser beam at .63 micrometers on the number of transverse modes is investigated. It is demonstrated that over a wide range of scattering angles, the contrast is determined primarily by the number of transverse modes, i.e. by the radius of the spatial field correlation, and is only slightly dependent on the dimensions and shape of the beam as well as the intensity distribution in the beam. These results may be useful in developing a rapid indication method of the radius of the spatial correlation of laser beams.

X-ray laser '' oscillator-amplifier'' experiments

International Nuclear Information System (INIS)

Shimkaveg, G.M.; Carter, M.R.; Young, B.K.F.; Walling, R.S.; Osterheld, A.L.; Trebes, J.E.; London, R.A.; Ratowsky, R.P.; Stewart, R.E.; Craxton, R.S.

1993-01-01

We present results from experiments directed toward increasing the degree of transverse coherence in x-ray laser beams. We have concentrated on the neon-like yttrium (Z=39) collisionally-pumped x-ray laser as the test system for these studies because of its unique combination of brightness, monochromaticity, and high-reflectivity optics availability. Attempts at improving laser performance using proximate feedback optics failed. Modest success has been found to date in ''double foil'' experiments, involving two x-ray lasers spatially separated by 29 cm and shot sequentially in an ''oscillator-amplifier'' configuration

Monochromatic x-ray radiography of laser-driven spherical targets using high-energy, picoseconds LFEX laser

Science.gov (United States)

Sawada, Hiroshi; Fujioka, S.; Lee, S.; Arikawa, Y.; Shigemori, K.; Nagatomo, H.; Nishimura, H.; Sunahara, A.; Theobald, W.; Perez, F.; Patel, P. K.; Beg, F. N.

2015-11-01

Formation of a high density fusion fuel is essential in both conventional and advanced Inertial Confinement Fusion (ICF) schemes for the self-sustaining fusion process. In cone-guided Fast Ignition (FI), a metal cone is attached to a spherical target to maintain the path for the injection of an intense short-pulse ignition laser from blow-off plasma created when nanoseconds compression lasers drive the target. We have measured a temporal evolution of a compressed deuterated carbon (CD) sphere using 4.5 keV K-alpha radiography with the Kilo-Joule, picosecond LFEX laser at the Institute of Laser Engineering. A 200 μm CD sphere attached to the tip of a Au cone was directly driven by 9 Gekko XII beams with 300 J/beam in a 1.3 ns Gaussian pulse. The LFEX laser irradiated on a Ti foil to generate 4.51 Ti K-alpha x-ray. By varying the delay between the compression and backlighter lasers, the measured radiograph images show an increase of the areal density of the imploded target. The detail of the quantitative analyses to infer the areal density and comparisons to hydrodynamics simulations will be presented. This work was performed with the support and under the auspices of the NIFS Collaboration Research program (NIFS13KUGK072). H.S. was supported by the UNR's International Activities Grant program.

Optimization of reactor power by taking into consideration temperature increase in a reactor pumped 3He-Xe laser

International Nuclear Information System (INIS)

Cetin, Fuesun

2009-01-01

In nuclear pumped lasers, gas parameters are optimized in a manner such that output power is increased for constructing a high power laser. Since output power increases with the increase of energy deposited in the gas, high output power requires high pumping power. However, the high energy loading results in elevated gas temperature. Temperature increase of this magnitude can detrimentally influence the laser gain and efficiency, since it negatively impacts several important laser kinetic.processes. This fact may cause laser output to abruptly terminate before the peak of the pump pulse [1-3]. A nuclear pumped laser using a volumetric energy source through the 3 He(n, p) 3 H reaction has here been considered. It is assumed that TRIGA Mark II Reactor at Istanbul Technical University is used for nuclear pumping as the neutron source. In the previous papers, the optimal parameters for improving both output power and optical homogeneity were determined [4-5]. Spatial and temporal variations of gas temperature during pumping pulse for maximum peak power (1200 MW) were determined for various operating pressures in Ref. [6]. It was seen that gas temperature reaches up to 1000 0 K near the peak of the pumping pulse for the initial pressures of 1-4 atm. This means that laser output may terminate before the peak of the pump pulse due to overheating of laser gas. Under these conditions, a question arises about a further optimisation taking into consideration gas temperature. This question has been examined in this study. Experimental results (Batyrbekov et al, 1989) showed that temperature rise up to 650 C had no influence on Xe laser characteristics [ 7]. Therefore, It has here been assumed that the lasing will terminate when gas temperature reaches 1000 0 K for a Xe-laser with 3 He buffer gas. Under these conditions optimum reactor power is investigated by taking into consideration lasing duration also. (orig.)

Generation of 300 MeV Quasi-Monochromatic Electron Beams from Laser Wakefield and Initiation of Photonuclear Reactions

Science.gov (United States)

Maksimchuk, A.; Beene, J. R.

2005-10-01

In the interaction of 30 fs, 40 TW Ti:sapphire Hercules laser at the University of Michigan, which is focused to the intensity of 10^19 W/cm^2 onto a supersonic He gas jet with electron density close to the resonant density, we observed quasi-monoenergetic electron beams with energy up to 300 MeV and angular divergence of about 10 mrad. The results on characterization of relativistic electron beam in terms of energy spread, its charge, divergence and pointing stability will be presented. 2D PIC simulations performed for the parameters close to the experimental conditions show the evolution of the laser pulse in plasma, electron injection, and the specifics of electron acceleration observed in experiments. Resulted relativistic electron beams have been used to perform gamma-neutron activation of ^12C and ^63Cu and photo-fission of ^238U. We demonstrated that approximately 10^6 reaction per shot has been produced in each case. This work was supported by the NSF through the Physics Frontier Center FOCUS. JRB, DRS, DWS, and CRV acknowledge support by the DOE under contract DE-AC05-00OR22725 with UT-Battelle, LLC.

Dichromatic laser radiation effects on DNA of Escherichia coli and plasmids

Science.gov (United States)

Martins, W. A.; Polignano, G. A. C.; Guimarães, O. R.; Geller, M.; Paoli, F.; Fonseca, A. S.

2015-04-01

Dichromatic and consecutive laser radiations have attracted increased attention for clinical applications as offering new tools for the treatment of dysfunctional tissues in situations where monochromatic radiation is not effective. This work evaluated the survival, filamentation and morphology of Escherichia coli cells, and the induction of DNA lesions, in plasmid DNA exposed to low-intensity consecutive dichromatic laser radiation. Exponential and stationary wild type and formamidopyrimidine DNA glycosylase/MutM protein deficient E. coli cultures were exposed to consecutive low-intensity dichromatic laser radiation (infrared laser immediately after red laser) to study the survival, filamentation and morphology of bacterial cells. Plasmid DNA samples were exposed to dichromatic radiation to study DNA lesions by electrophoretic profile. Dichromatic laser radiation affects the survival, filamentation and morphology of E. coli cultures depending on the growth phase and the functional repair mechanism of oxidizing lesions in DNA, but does not induce single/double strands breaks or alkali-labile DNA lesions. Results show that low-intensity consecutive dichromatic laser radiation induces biological effects that differ from those induced by monochromatic laser radiation, suggesting that other therapeutic effects could be obtained using dichromatic radiation.

Photoelectric-enhanced radiation therapy with quasi-monochromatic computed tomography.

Science.gov (United States)

Jost, Gregor; Mensing, Tristan; Golfier, Sven; Lawaczeck, Rüdiger; Pietsch, Hubertus; Hütter, Joachim; Cibik, Levent; Gerlach, Martin; Krumrey, Michael; Fratzscher, Daniel; Arkadiev, Vladimir; Wedell, Reiner; Haschke, Michael; Langhoff, Norbert; Wust, Peter; Lüdemann, Lutz

2009-06-01

Photoelectric-enhanced radiation therapy is a bimodal therapy, consisting of the administration of highly radiation-absorbing substances into the tumor area and localized regional irradiation with orthovoltage x-rays. Irradiation can be performed by a modified computed tomography (CT) unit equipped with an additional x-ray optical module which converts the polychromatic, fan-shaped CT beam into a monochromatized and focused beam for energy-tuned photoelectric-enhanced radiotherapy. A dedicated x-ray optical module designed for spatial collimation, focusing, and monochromatization was mounted at the exit of the x-ray tube of a clinical CT unit. Spectrally resolved measurements of the resulting beam were performed using an energy-dispersive detection system calibrated by synchrotron radiation. The spatial photon fluence was determined by film dosimetry. Depth-dose measurements were performed and compared to the polychromatic CT and a therapeutic 6 MV beam. The spatial dose distribution in phantoms using a rotating radiation source (quasimonochromatic CT and 6 MV, respectively) was investigated by gel dosimetry. The photoelectric dose enhancement for an iodine fraction of 1% in tissue was calculated and verified experimentally. The x-ray optical module selectively filters the energy of the tungsten Kalpha emission line with an FWHM of 5 keV. The relative photon fluence distribution demonstrates the focusing characteristic of the x-ray optical module. A beam width of about 3 mm was determined at the isocenter of the CT gantry. The depth-dose measurements resulted in a half-depth value of approximately 36 mm for the CT beams (quasi-monochromatic, polychromatic) compared to 154 mm for the 6 MV beam. The rotation of the radiation source leads to a steep dose gradient at the center of rotation; the gel dosimetry yields an entrance-to-peak dose ratio of 1:10.8 for the quasi-monochromatic CT and 1:37.3 for a 6 MV beam of the same size. The photoelectric dose enhancement

Influence of left right asymmetry degrees of freedom in self-consistent calculation of 20Ne

International Nuclear Information System (INIS)

Marcos, S.; Flocard, H.; Heenen, P.H.

1983-06-01

Within a constrained Hartree-Fock calculation we investigate the effects of left right asymmetric degrees of freedom associated with the channel 16 O + 4 He 20 Ne. We find a large softness of 20 Ne against octupole deformation. The optimal solution after restoration of the parity by means of a projection shows a pronouned 16 O + 4 He clustering. A generator coordinate calculation along the collective path confirms this conclusion. Once center of mass motion effects are taken into account a good agreement with experiment is found

Primary populations of metastable antiprotonic $^{4}He$ and $^{3}He$ atoms

CERN Document Server

Hori, Masaki; Hayano, R S; Ishikawa, T; Sakuguchi, J; Tasaki, T; Widmann, E; Yamaguchi, H; Torii, H A; Juhász, B; Horváth, D; Yamazaki, T

2002-01-01

Initial population distributions of metastable antiprotonic **4He and **3He atoms over principal and angular momentum quantum numbers were investigated using laser spectroscopy. The total fractions of antiprotons captured into the metastable states of the atoms were deduced. Cascade calculations were performed using the measure populations to reproduce the delayed annihilation time spectrum. Results showed agreement between the simulated and measured spectra. (Edited abstract) 30 Refs.

Influence of ionizing irradiation on the antioxidant enzymes of Vicia faba L.

Directory of Open Access Journals (Sweden)

El-Beltagi, Hossam E. S.

2010-09-01

Full Text Available The seeds of Vicia faba L. Giza 834 were exposed to γ-irradiation at dose levels of 2.5, 5.0, 10.0 and 20.0 kGy and after that exposed to He–Ne (632.8 nm or diode (650.0 nm laser irradiation for 5 min. The activities of POD, APOX, CAT, SOD and GST enzymes were significantly stimulated and this stimulation reached its maximum at a dose level of 5.0 kGy for enzymes POD, APOX, CAT and SOD, but for GST enzyme at a dose level 10.0 kGy. For He- Ne laser, with or without different doses (2.5, 5.0, 10.0 and 20.0 kGy of γ-irradiation, enzyme induction was significantly stimulated and positively correlated with the dose levels of γ-irradiation in combination with the He-Ne treatment. There was a significant increase in the concentration of MDA and this increase was more pronounced at dose level 20.0 kGy (38.2 μmol/g d.w compared to the control (3.9 μmol/g d.w. Laser treatment by He–Ne laser or diode laser only caused a slight increase (P 2O2 content significantly increased in all treatments and this increase reached its maximum at dose level 20.0 kGy (36.3 μmol/g d.w compared to the control (2.3 μmol/g d.w.. On the other hand, He-Ne or diode laser treatments combined with γ-irradiation significantly decreased in comparison with γ-irradiation treatments alone. In the case of glutathione content, there were significant increases by γ-irradiation at dose levels 2.5, 5.0, 10.0 and 20.0 kGy. Furthermore, with a combination of γ-irradiation and He-Ne or diode laser, a marked increase in glutathione content was found and was more pronounced than that of gamma irradiation alone.Semillas de Vicia faba L. Giza 834 fueron expuestas a γ-irradiación a dosis de 2.5, 5.0, 10.0 y 20.0 kGy y después expuesta a una radiación laser de He–Ne (632.8 nm o de diodo (650.0 nm durante 5 minutos. Las actividades de las enzimas POD, APOX, CAT, SOD y GST fueron favorecidas significativamente, y éstas alcanzaron un máximo a una dosis de 5.0 kGy para las enzimas

Application of FEL technique for constructing high-intensity, monochromatic, polarized gamma-sources at storage rings

Energy Technology Data Exchange (ETDEWEB)

Saldin, E.L.; Schneidmiller, E.A.; Ulyanov, Yu.N. [Automatic Systems Corporation, Samara (Russian Federation)] [and others

1995-12-31

A possibility to construct high-intensity tunable monochromatic{gamma}-source at high energy storage rings is discussed. It is proposed to produce {gamma}-quanta by means of Compton backscattering of laser photons on electrons circulating in the storage. The laser light wavelength is chosen in such a way that after the scattering, the electron does not leave the separatrix. So as the probability of the scattering is rather small, energy oscillations are damped prior the next scattering. As a result, the proposed source can operate in {open_quotes}parasitic{close_quote} mode not interfering with the main mode of the storage ring operation. Analysis of parameters of existent storage rings (PETRA, ESRF, Spring-8, etc) shows that the laser light wavelength should be in infrared, {lambda}{approximately} 10 - 400 {mu}m, wavelength band. Installation at storage rings of tunable free-electron lasers with the peak and average output power {approximately} 10 MW and {approximately} 1 kW, respectively, will result in the intensity of the {gamma}-source up to {approximately} 10{sup 14}s{sup -1} with tunable {gamma}-quanta energy from several MeV up to several hundreds MeV. Such a {gamma}-source will reveal unique possibilities for precision investigations in nuclear physics.

α cluster structures in unbound states in 19Ne

Science.gov (United States)

Otani, Reiji; Iwasaki, Masataka; Ito, Makoto

2016-06-01

Cluster structures in 19Ne are studied by the microscopic and macroscopic cluster models. In the microscopic calculation, the coupled-channels problem of (3He+16O) + (α+15O) is solved, and the adiabatic energy surfaces, which are the series of the energy eigenvalues as a function of the He-O distance, are investigated. In the adiabatic energy curves, the several local minima are generated in the spatial region of the small core distance, where the neutron hole inside of the He or O nucleus is strongly coupled to the residual nuclei. The energy spectra, which are constructed from the strong coupling states, nicely reproduce the the low-lying energy levels in the 19Ne nucleus. In the macroscopic approach, the α + 15O potential is evaluated from the elastic scattering of the α + 15N system, and the resonant levels of the α + 15O system are calculated under the absorbing boundary condition. The potential model predicts the existence of the resonances above the α threshold, which has a weak-coupling scheme of the α particle and one hole inside of the 16O nucleus. The extended microscopic calculations of (3He+16O) + (α+15O) + (5He+14O) are performed in order to see the coupling effect of the 5p-2h configuration, which corresponds to the shell model limit of the 5He + 14O cluster configuration. The extended calculation suggests that the 5He + 14O configuration plays an important role on the formation of the 3/2+ resonance at 0.5 MeV with respect to the α threshold.

Development of short pulse laser pumped x-ray lasers

International Nuclear Information System (INIS)

Dunn, J; Osterheld, A L; Hunter, J R; Shlyaptsev, V N

2000-01-01

X-ray lasers have been extensively studied around the world since the first laboratory demonstration on the Novette laser at LLNL in 1984 [l]. The characteristic properties of short wavelength, high monochromaticity, collimation and coherence make x-ray lasers useful for various applications. These include demonstrations of biological imaging within the water window, interferometry of laser plasmas and radiography of laser-heated surfaces. One of the critical issues has been the high power pump required to produce the inversion. The power scaling as a function of x-ray laser wavelength follows a -k4 to law. The shortest x-ray laser wavelength of ∼ 35 (angstrom) demonstrated for Ni-like All was at the limit of Nova laser capabilities. By requiring large, high power lasers such as Nova, the shot rate and total number of shots available have limited the rapid development of x-ray lasers and applications. In fact over the last fifteen years the main thrust has been to develop more efficient, higher repetition rate x-ray lasers that can be readily scaled to shorter wavelengths. The recent state of progress in the field can be found in references. The objective of the project was to develop a soft x-ray laser (XRL) pumped by a short pulse laser of a few joules. In effect to demonstrate a robust, worlung tabletop x-ray laser at LLNL for the first time. The transient collisional scheme as proposed by Shlyaptsev et al [8, 9] was the candidate x-ray laser for study. The successful endeavour of any scientific investigation is often based upon prudent early decisions and the choice of this scheme was both sound and fruitful. It had been demonstrated very recently for Ne-like Ti at 326 A using a small tabletop laser [10] but had not yet reached its full potential. We chose this scheme for several reasons: (a) it was a collisional-type x-ray laser which has been historically the most robust; (b) it had the promise of high efficiency and low energy threshold for lasing; (c) the

Continuous anti-Stokes Raman laser operation

International Nuclear Information System (INIS)

Feitisch, A.; Muller, T.; Welling, H.; Wellegehausen, B.

1988-01-01

The anti-Stokes Raman laser (ASRL) process has proved to be a method that works well for frequency upconversion and for the generation of powerful tunable narrowband (pulsed) laser radiation in the UV and VUV spectral range. This conversion process allows large-frequency shifts in single step, high output energies, and high efficiencies. A basic requirement is population inversion on a two-photon transition, where, in general, the upper level of the transition should be metastable. Up to now the ASRL technique has only been demonstrated for the pulsed regime, where the necessary population inversion was generated by photodissociation or inner shell photoionization. These inversion techniques, however, cannot be transferred to cw operation of an ASRL, and, therefore, other inversion techniques have to be developed. Here a novel approach for the creation of the necessary population inversion is proposed, that uses well-known cw gas lasers as the active material for the conversion process. The basic idea is to use either existing two-photon population inversions in a cw laser material or to generate the necessary population inversion by applying a suitable population transfer process to the material. A natural two-photon inversion situation in a laser material is evident whenever a cascade laser can be operated. Cascade laser-based anti-Stokes schemes are possible in a He-Ne laser discharge, and investigations of these schemes are discussed

Determination of the neutron detection efficiency of an NE213 scintillator for En=2.5 to 16 MeV using the 2H(d,n)3He reaction

International Nuclear Information System (INIS)

Al-Ohali, M.A.; Aksoy, A.; Coban, A.

1997-01-01

The absolute efficiency of an NE213 liquid scintillator of 12.7 cm diameter and 5.08 cm thickness was measured in the neutron energy range 2.5-16 MeV using the 2 H(d,n) 3 He reaction as a source of monoenergetic neutrons. The efficiencies were measured at the time-of-flight facility of Triangle Universities Nuclear Laboratory TUNL. The experimental data are compared to calculations from the Monte Carlo code NEFF of Physikalisch-Technische Bundesanstalt, Braunschweig, Germany PTB. (orig.)

Editorial special issue on "Laser Doppler vibrometry"

Science.gov (United States)

Vanlanduit, Steve; Dirckx, Joris

2017-12-01

The invention of the laser in 1960 has opened up many opportunities in the field of measurement science and technology. Just a few years after the invention of the laser, a novel fluid flow measurement technique based on the Doppler effect was introduced: at that moment the laser Doppler anemometer or shortly LDA [1] was born. The technique enabled fluid velocity measurement by using the light of a He-Ne beam which was scattered by very small polystyrene spheres entrained in the fluid. Later on, in the late nineteen seventees it was recognized that the detection of the Doppler frequency shift that occurs when light is scattered by a moving surface can also be used to measure the vibration velocity of an object. The instrument to perform these vibration measurements was called the laser Doppler vibrometer or LDV [2]. In the last decades several technological advances were made in the field of laser Doppler vibrometry. The result is that nowadays, velocity measurements of fluids (using LDA) and vibrating objects (using LDV) are performed in many challenging applications in different fields (microelectronics, civil structures, biomedical engineering, material science, etc.).

Láser helio-neón combinado con clorhexidina al 0,2 %.: Efectos clínicos y microbiológicos en el tratamiento de la gingivitis crónica Helium-neon laser combined with 0.2% chlorhexidine: Clinical and microbiological effects in the treatment of chronic gingivitis.

Directory of Open Access Journals (Sweden)

Tatiana Peña Ruiz

2007-09-01

Full Text Available La gingivitis crónica constituye una de las formas más frecuentes de enfermedad periodontal, caracterizada por la inflamación crónica de la encías, tumefacción, enrojecimiento y sangramiento. Su principal factor de riesgo lo constituye la microbiota del surco gingival, que resulta necesario, pero no suficiente para desencadenarla. Se realizó un ensayo clínico-terapéutico fase II, controlado, aleatorizado y a simple ciegas, para evaluar los efectos clínicos y microbiológicos del tratamiento combinado de la radiación láser helio-neón (He-Ne con la clorhexidina al 0,2 %. Todos los pacientes recibieron tratamiento inicial; al mes de finalizado este, se distribuyeron aleatoriamente en 2 grupos: un grupo estudio que recibió la combinación láser-neón y clorhexidina al 0,2 % y otro grupo control que solo recibió clorhexidina al 0,2 %. Se realizó una evaluación a los 15, 30 y 45 días, con criterios de eficacia clínicos y microbiológicos. Los resultados clínicos fueron satisfactorios en el grupo estudio con predominio de los morfotipos I, caracterizados por cocos gramnegativos y positivos, compatibles con un periodonto sano. Los eventos adversos detectados con esta terapéutica fueron mínimos, todos relacionados con la somnolencia.Chronic gingivitis is one of the most common periodontal diseases that is characterized by chronic inflammation, tumefaction, redness and bleeding. The main risk factor is gingival sulcus microbiota that is essential but not enough to unleash it. A phase II controlled randomized blind clinical/therapeutical assay was conducted to evaluate the clinical and microbiological effects of the combined treatment based on helium-neon laser (He-Ne with 0.2% chlorhexidine. All the patients were initially treated; after a month, they were randomly distributed into two groups, that is, the study group received a helium-neon laser plus 0.2% chlorhexidine combination and the control group was treated with 0

Time resolved x-ray pinhole photography of compressed laser fusion targets

International Nuclear Information System (INIS)

Attwood, D.T.

1976-01-01

Use of the Livermore x-ray streak camera to temporally record x-ray pinhole images of laser compressed targets is described. Use is made of specially fabricated composite x-ray pinholes which are near diffraction limited for 6 A x-rays, but easily aligned with a He--Ne laser of 6328 A wavelength. With a 6 μm x-ray pinhole, the overall system can be aligned to 5 μm accuracy and provides implosion characteristics with space--time resolutions of approximately 6 μm and 15 psec. Acceptable criteria for pinhole alignment, requisite x-ray flux, and filter characteristics are discussed. Implosion characteristics are presented from our present experiments with 68 μm diameter glass microshell targets and 0.45 terawatt, 70 psec Nd laser pulses. Final implosion velocities in excess of 3 x 10 7 cm/sec are evident

Mathematical simulation of the amplification of 1790-nm laser radiation in a nuclear-excited He - Ar plasma containing nanoclusters of uranium compounds

Science.gov (United States)

Kosarev, V. A.; Kuznetsova, E. E.

2014-02-01

The possibility of applying dusty active media in nuclearpumped lasers has been considered. The amplification of 1790-nm radiation in a nuclear-excited dusty He - Ar plasma is studied by mathematical simulation. The influence of nanoclusters on the component composition of the medium and the kinetics of the processes occurring in it is analysed using a specially developed kinetic model, including 72 components and more than 400 reactions. An analysis of the results indicates that amplification can in principle be implemented in an active laser He - Ar medium containing 10-nm nanoclusters of metallic uranium and uranium dioxide.

Propagation and stability characteristics of a 500-m-long laser-based fiducial line for high-precision alignment of long-distance linear accelerators.

Science.gov (United States)

Suwada, Tsuyoshi; Satoh, Masanori; Telada, Souichi; Minoshima, Kaoru

2013-09-01

A laser-based alignment system with a He-Ne laser has been newly developed in order to precisely align accelerator units at the KEKB injector linac. The laser beam was first implemented as a 500-m-long fiducial straight line for alignment measurements. We experimentally investigated the propagation and stability characteristics of the laser beam passing through laser pipes in vacuum. The pointing stability at the last fiducial point was successfully obtained with the transverse displacements of ±40 μm level in one standard deviation by applying a feedback control. This pointing stability corresponds to an angle of ±0.08 μrad. This report contains a detailed description of the experimental investigation for the propagation and stability characteristics of the laser beam in the laser-based alignment system for long-distance linear accelerators.

High-pressure {sup 4}He drift tubes for fissile material detection

Energy Technology Data Exchange (ETDEWEB)

Wang, Zhehui, E-mail: zwang@lanl.gov [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Morris, Christopher L. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Gray, F.E. [Regis University, Denver, CO 80221 (United States); Bacon, J.D.; Brockwell, M.I.; Chang, D.Y.; Chung, K.; Dai, W.G.; Greene, S.J.; Hogan, G.E.; Lisowski, P.W.; Makela, M.F.; Mariam, F.G.; McGaughey, P.L. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Mendenhall, M. [California Institute of Technology, Pasadena, CA 91125 (United States); Milner, E.C.; Miyadera, H.; Murray, M.M.; Perry, J.O.; Roybal, J.D. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); and others

2013-03-01

A detector efficiency model based on energy extraction from neutrons is described and used to compare {sup 4}He detectors with liquid scintillators (EJ301/NE-213). Detector efficiency can be divided into three regimes: single neutron scattering, multiple neutron scattering, and a transition regime in-between. For an average fission neutron of 2 MeV, the amount of {sup 4}He needed would be about 1/4 of the amount of the mass of EJ301/NE-213 in the single-scattering regime. For about 50% neutron energy extraction (1 MeV out of 2 MeV), the two types of detectors ({sup 4}He in the transition regime, EJ301 still in the single-scattering regime) have comparable mass, but {sup 4}He detectors can be much larger depending on the number density. A six-tube 11-bar-pressure {sup 4}He detector prototype is built and tested. Individual electrical pulses from the detector are recorded using a 12-bit digitizer. Differences in pulse rise time and amplitudes, due to different energy loss of neutrons and gamma rays, are used for neutron/gamma separation. Several energy spectra are also obtained and analyzed.

Compact 4-kHz XeF-laser with multisectional discharge gap

Science.gov (United States)

Andramanov, A. V.; Kabaev, S. A.; Lazhintsev, Boris V.; Nor-Arevyan, Vladimir A.; Selemir, V. D.

2005-03-01

An electric-discharge XeF-laser with a pulse repetition rate up to 4 kHz was developed. The laser electrode unit was made on the basis of plate-like electrodes with inductive-capacity discharge stabilization. The narrow discharge width laser energy was 3 mJ by using He/Xe/NF3 and Ne/Xe/NF3 mixtures at the total pressure of 0.8 atm and 1.2 atm, respectively. The maximum laser efficiency was ~ 0.73% The gas flow was formed with the help of a diametrical fan rotated by the direct-current motor with 80 W power. The gas velocity of 20 m/s in the interelectrode gap was achieved. The laser pulse energy for a pulse repetition rate up to 3.5...4 kHz was virtually equal to the laser pulse energy in the infrequently-repeating-pulse regime. The average output power of 12 W at the pulse repetition rate of 4 kHz was achieved. The relative root-mean-square pulse-to-pulse variation of the output energy σ = 2.5% was reached.

Gas-dynamic perturbations in an electric-discharge repetitively pulsed DF laser and the role of He in their suppression

Energy Technology Data Exchange (ETDEWEB)

Evdokimov, P A; Sokolov, D V [Russian Federal Nuclear Center ' All-Russian Research Institute of Experimental Physics' , Sarov, Nizhnii Novgorod region (Russian Federation)

2015-11-30

The gas-dynamic perturbations in a repetitively pulsed DF laser are studied using a Michelson interferometer. Based on the analysis of experimental data obtained in two experimental sets (working medium without buffer gas and with up to 90% of He), it is concluded that such phenomena as isentropic expansion of a thermal plug, gas heating by shock waves and resonance acoustic waves do not considerably decrease the upper limit of the pulse repetition rate below a value determined by the time of the thermal plug flush out of the discharge gap. It is suggested that this decrease for a DF laser with the SF{sub 6} – D{sub 2} working mixture is caused by the development of overheat instability due to an increased energy deposition into the near-electrode regions and to the formation of electrode shock waves. Addition of He to the active media of the DF laser changes the discharge structure and improves its homogeneity over the discharge gape cross section, thus eliminating the reason for the development of this instability. A signification dilution of the active medium of a DF laser with helium up to the atmospheric pressure allowed us to achieve the limiting discharge initiation frequencies with the active medium replacement ratio K ∼ 1. (active media)

Excitation mechanisms in 1 mJ picosecond laser induced low pressure He plasma and the resulting spectral quality enhancement

Energy Technology Data Exchange (ETDEWEB)

Idris, Nasrullah; Lahna, Kurnia; Abdulmadjid, Syahrun Nur [Department of Physics, Faculty of Mathematics and Natural Sciences, Syiah Kuala University, Darussalam, Banda Aceh 23111, NAD (Indonesia); Ramli, Muliadi [Department of Chemistry, Faculty of Mathematics and Natural Sciences, Syiah Kuala University, Darussalam, Banda Aceh 23111, NAD (Indonesia); Suyanto, Hery [Department of Physics, Faculty of Mathematics and Natural Sciences, Udayana University, Kampus Bukit Jimbaran, Denpasar 80361, Bali (Indonesia); Marpaung, Alion Mangasi [Department of Physics, Faculty of Mathematics and Natural Sciences, Jakarta State University, 10 Rawamangun, Jakarta (Indonesia); Pardede, Marincan [Department of Electrical Engineering, University of Pelita Harapan, 1100 M.H. Thamrin Boulevard, Lippo Village, Tangerang 15811 (Indonesia); Jobiliong, Eric [Department of Industrial Engineering, University of Pelita Harapan, 1100 M.H. Thamrin Boulevard, Lippo Village, Tangerang 15811 (Indonesia); Hedwig, Rinda; Lie, Zener Sukra [Department of Computer Engineering, Bina Nusantara University, 9 K.H. Syahdan, Jakarta 14810 (Indonesia); Research Center of Maju Makmur Mandiri Foundation, 40/80 Srengseng Raya, Jakarta 11630 (Indonesia); Suliyanti, Maria Margaretha [Research Center for Physics, Indonesia Institute of Sciences, Kawasan PUSPIPTEK, Serpong, Tangerang Selatan 15314, Banten (Indonesia); Lie, Tjung Jie; Kurniawan, Koo Hendrik, E-mail: kurnia18@cbn.net.id [Research Center of Maju Makmur Mandiri Foundation, 40/80 Srengseng Raya, Jakarta 11630 (Indonesia); Kagawa, Kiichiro [Fukui Science Education Academy, Takagi Chuou 2 choume, Fukui 910-0804 (Japan); Tjia, May On [Research Center of Maju Makmur Mandiri Foundation, 40/80 Srengseng Raya, Jakarta 11630 (Indonesia); Physics of Magnetism and Photonics Group, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, 10 Ganesha, Bandung 40132 (Indonesia)

2015-06-14

We report in this paper the results of an experimental study on the spectral and dynamical characteristics of plasma emission induced by 1 mJ picoseconds (ps) Nd-YAG laser using spatially resolved imaging and time resolved measurement of the emission intensities of copper sample. This study has provided the experimental evidence concerning the dynamical characteristics of the excitation mechanisms in various stages of the plasma formation, which largely consolidate the basic scenarios of excitation processes commonly accepted so far. However, it is also clearly shown that the duration of the shock wave excitation process induced by ps laser pulses is much shorter than those observed in laser induced breakdown spectroscopy employing nanosecond laser at higher output energy. This allows the detection of atomic emission due exclusively to He assisted excitation in low pressure He plasma by proper gating of the detection time. Furthermore, the triplet excited state associated with He I 587.6 nm is shown to be the one most likely involved in the process responsible for the excellent spectral quality as evidenced by its application to spectrochemical analysis of a number of samples. The use of very low energy laser pulses also leads to minimal destructive effect marked by the resulted craters of merely about 10 μm diameter and only 10 nm deep. It is especially noteworthy that the excellent emission spectrum of deuterium detected from D-doped titanium sample is free of spectral interference from the undesirable ubiquitous water molecules without a precleaning procedure as applied previously and yielding an impressive detection limit of less than 10 μg/g. Finally, the result of this study also shows a promising application to depth profiling of impurity distribution in the sample investigated.

CDW-EIS calculations for multiple ionization of Ne, Ar, Kr and Xe by the impact of H{sup +} and He{sup +}, including post-collisional electron emission

Energy Technology Data Exchange (ETDEWEB)

Montanari, C C; Miraglia, J E [Instituto de AstronomIa y FIsica del Espacio, casilla de correo 67, sucursal 28, C1428EGA, Buenos Aires (Argentina); Montenegro, E C, E-mail: mclaudia@iafe.uba.a [Instituto de FIsica, Universidade Federal de Rio de Janeiro, Caixa Postal 68528, Rio de Janeiro 21945-970, RJ (Brazil)

2010-08-28

We present theoretical single to quintuple ionization cross sections for Ne, Ar, Kr and Xe bombarded by H{sup +} and He{sup +}. Post-collisional contributions due to Auger-like processes are taken into account using recent photoionization data. The present continuum distorted wave-eikonal initial state (CDW-EIS) and first Born approximation results are compared with the experimental data available in the energy range of 50-10 000 keV amu{sup -1} for H{sup +} on Ne and Ar, and 50-1000 keV amu{sup -1} for the other cases. In general, the combination of the CDW-EIS with the post-collisional branching ratios describes well the multiple ionization data above 300 keV amu{sup -1}, showing a clear tendency to coalesce with the first Born approximation at high energies. The surprising result of this work is the good performance of the first Born approximation which describes rather well the experimental data of double and triple ionization, even in the intermediate energy range (50-300 keV amu{sup -1}), where direct ionization is the dominant contribution.

Laser Hazards Bibliography, January 1991

Science.gov (United States)

1991-01-31

632.8 and 488 nm, Biull Eksp Biol Med, 85(5): 537-539 (1978). 183. Urazalin, Zh. B., Effect of monochromatic red light on mandibular fracture healing...Dtsch. Med. Wschr. 104: 1393-1394, (1979). 49. Fechner, P. U., Laser-coagulation of ruptured fixation suture after lens implantation, J Am Intraocul...spinal neuron receptive fields, Brain Res, 152(2): 348-352 (1978). 83. Henderson, B. M., et al., The laser in pediatric surgery, J Ped Surg, 3: 263

Efficacy of fractional lasers in treating alopecia: a literature review.

Science.gov (United States)

Perper, Marina; Aldahan, Adam S; Fayne, Rachel A; Emerson, Christopher P; Nouri, Keyvan

2017-11-01

Hair loss stemming from different types of alopecia, such as androgenic alopecia and alopecia areata, negatively affects over half the population and, in many circumstances, causes serious psychosocial distress. Current treatment options for alopecia, such as minoxidil, anthralin, and intralesional corticosteroids, vary efficacy and side effect profiles. It is known that low-level laser/light therapies (LLLT), or photobiomodulations, such as the US FDA-cleared HairMax Lasercomb®, He-Ne laser, and excimer laser, are relatively affordable, user-friendly, safe, and effective forms of treatment for hair loss. While less is known about the effectiveness of fractional lasers for combating hair loss, research suggests that by creating microscopic thermal injury zones, fractional lasers may cause an increase in hair growth from a wound healing process, making them potential therapeutic options for alopecia. A literature review was performed to evaluate the effectiveness of fractional lasers on hair regrowth. The specific fractional laser therapies include the 1550-nm nonablative fractional erbium-glass laser, the ablative fractional 2940-nm erbium:YAG laser, and the ablative fractional CO 2 fractional laser. Additional randomized controlled trials are necessary to further evaluate the effectiveness of the lasers, as well as to establish appropriate parameters and treatment intervals.

Non-intrusive, fast and sensitive ammonia detection by laser photothermal deflection

International Nuclear Information System (INIS)

Vries, H.S.M. de; Harren, F.J.M.; Wyers, G.P.; Otjes, R.P.; Slanina, J.; Reuss, J.

1995-01-01

A recently developed non-intrusive photothermal deflection (PTD) instrument allows sensitive, rapid and quantitative detection of local ammonia concentrations in the air. Ammonia is vibrationally excited by an infrared CO 2 laser in an intracavity configuration. A HeNe beam passing over the CO 2 laser beam (multipass arrangement) is deflected by the induced refractive index gradient. The detection limit for ammonia in ambient air is 0.5 ppbv with a spatial resolution of a few mm 3 . The time resolution is 0.1 s (single line) or 15 s (multi line). The system is fully automated and suited for non-stop measuring periods of at least one week. Results were compared to those obtained with a continuous-flow denuder (CFD). (author)

Laser-induced fluorescences due to quadrupole moment transition and Stark effect in a He glow discharge

International Nuclear Information System (INIS)

Sakai, Hisashi; Takiyama, Ken; Kimura, Masahiko; Yamasaki, Motokuni; Fujita, Toshiaki; Oda, Toshiatsu; Kawasaki, Ken.

1993-01-01

The electric quadrupole moment transition and the Stark effect are investigated in a He hollow cathode discharge with laser-induced fluorescence method. It is shown that the forbidden transition from 2 1 S to 3 1 D in the negative glow is dominantly due to the quadrupole moment transition. This absorption coefficient is obtained from the laser-induced fluorescence intensity measurement in which the collisional transfers are taken into account. The result agrees with the theoretical coefficient. In the cathode dark space the fluorescence due to the Stark effect is also observed. Spatial distribution of the fluorescence is discussed, compared with the electric field distribution in the dark space. (author)

Theoretical-experimental study of the non-thermal effects of the polarized laser radiation in living tissues

International Nuclear Information System (INIS)

Ribeiro, M.S.

1991-01-01

In the present research we had as a fundamental objective to analyse the non-thermal effects of the laser polarized light in biological tissues. These effects were performed with low power laser output. The theoretical procedure consisted in looking for a simple model which connects the effect of light polarized with microscopically rough tissues using well established physical concepts. Experimentally, we created artificial wounds on the back of animals using liquid nitrogen (this method was chosen because it does not interfere in the biochemistry of the animal tissue). For the wound irradiation we have utilized a He-Ne attached to an optical system. (author)

The observation of the Ne-like ion resonance line satellites for CrXV ... Ni XIX CO2-laser produced plasma

International Nuclear Information System (INIS)

Khakhalin, S.Ya.; Faenov, A.Ya.; Skobelev, I.Yu.; Pikuz, S.A.; Nilsen, J.; Osterheld, A.

1994-01-01

We present an analysis of dielectronic satellite spectra of Ne-like ion resonance lines for elements from Cr to Ni. For these low-Z elements, we use spectra from strongly underionized CO 2 -laser produced plasma to minimize the emission from open L-shell ions. This simplifies the spectra and allows the identification of satellite lines caused by radiative transitions from autoionizing states of sodium like ions. Good agreement between the satellite structure calculations and the experimental emission spectra is obtained. (orig.)

Strong optical feedback in birefringent dual frequency laser

Institute of Scientific and Technical Information of China (English)

Mao Wei; Zhang Shu-Lian

2006-01-01

Strong optical feedback in a birefringent dual frequency He-Ne laser with a high reflectivity feedback mirror has been investigated for the first time. The output characteristics of two orthogonally polarized modes are demonstrated in two different optical feedback cases: one is for both modes being fed back and the other is for only one of the modes being fed back. Strong mode competition can be observed between the two modes with strong optical feedback. And when one mode's intensity is near its maximum, the other mode is nearly extinguished. When both modes are fed back into the laser cavity, the mode competition is stronger than when only one mode is fed back. The difference in initial intensity between the two orthogonally polarized modes plays an important role in the mode competition, which has been experimentally and theoretically demonstrated.

Laser-assisted electron-atom collisions

International Nuclear Information System (INIS)

Mason, N.J.

1989-01-01

New developments in our understanding of the electron-atom collision process have been made possible by combining the use of highly monochromatic electron beams and intense CO 2 lasers. This paper reviews such experiments and discusses possible future progress in what is a new field in atomic collision physics. (author)

Measurement of the 6He Decay Produced by the 9Be(n, α) 6 He Reaction

Science.gov (United States)

Cook, Katelyn; Coats, Micah; Yuly, Mark; Padalino, Stephen; Sangster, Craig; Regan, Sean

2016-10-01

The OMEGA laser at LLE is routinely used to implode gas-filled capsules to study light ion fusion reaction rates of interest to stellar nucleosynthesis. As a first step toward a possible measurement of the 3H(t,γ)6He radiative capture reaction, a detector system capable of measuring the 801 ms half-life of 6He has been developed and is being tested using 6He nuclei produced via the 9Be(n,α)6He reaction. Deuterons from the SUNY Geneseo tandem Pelletron produce neutrons in a thick deuterated polyethylene target via the 2H(d,n)3He reaction. These neutrons are allowed to strike a beryllium target placed in front of a silicon ΔE-E detector telescope, which is used to identify the β particles from 6He decay. Following an approximately five second long activation period, the beryllium sample is immediately counted for about five seconds. The pulse heights for each detector and the timestamp are recorded using a specially configured femtoDAQ acquision system and used to measure the decay curve. Funded in part by a Grant from the DOE through the Laboratory for Laser Energetics.

Theoretical and practical aspects of pre-sowing laser biostimulation of the seeds

International Nuclear Information System (INIS)

Gładyszewska, B.; Kornas-Czuczwar, B.; Koper, R.; Lipski, S.

1998-01-01

Against the background of recent literature review basic aspects of the mechanism responsible for pre-sowing laser bio-stimulation of the seeds were discussed. Developed by professor W. Sedlak theory of bioplasma was the main point of reference. Presented results of own research works proved the positive influence of pre-sowing laser treatment of seeds on their yielding and nutritive value. The yield rises caused by pre-sowing laser seed bio-stimulation for some examined plant crops were as follows: maize (from 10 to 15%), spring wheat (from 20 to 30%), spring barley (from 20 to 25%), sugar beets (from 10 to 30%), rape seeds (from 10 to 15%). The quality of crops frawn from the laser treated seeds was also better than the control ones. For example, the protein content in grain of spring wheat grown from the seeds bio-stimulated with a the He-Ne laser increased from about 12 up to 14%. Similarly, in roots of the sugar beets grown from laser treated seeds, the sugar content rose from about 15 up to about 17% [pl

Hartmann-Shack wave front measurements for real time determination of laser beam propagation parameters

International Nuclear Information System (INIS)

Schaefer, B.; Luebbecke, M.; Mann, K.

2006-01-01

The suitability of the Hartmann-Shack technique for the determination of the propagation parameters of a laser beam is faced against the well known caustic approach according to the ISO 11146 standard. A He-Ne laser (543 nm) was chosen as test beam, both in its fundamental mode as well as after intentional distortion, introducing a moderate amount of spherical aberration. Results are given for the most important beam parameters M 2 , divergence, and beam widths, indicating an agreement of better than 10% and for adapted beam diameter <5%. Furthermore, the theoretical background, pros and cons, as well as some features of the software implementation for the Hartmann-Shack sensor are briefly reviewed

Physical grounds for biological effect of laser radiation

International Nuclear Information System (INIS)

Rubinov, A N

2003-01-01

A new approach to the understanding of biological activity caused by low-intensity laser radiation, in which coherence is a factor of paramount importance, has been developed. It is based on the dipole interaction of gradient laser fields with cells, organelles and membranes. The laser intensity gradients in an object arise due to the interference of the light scattered by the tissue with the incident light beam (speckle formation). Apart from speckles, different types of light spatial modulation can be created deliberately using different schemes for beam interference. It is shown that gradient laser fields may cause spatial modulation of the concentration of particles and increase their 'partial temperature'. This paper presents the results of experimental observation of trapping of different types of particles, including human lymphocytes, in the interference fields of the He-Ne laser. The sweep-net effect on particles of different sizes on moving the laser field is demonstrated and crystal-like self-organization of particles in the laser gradient field is observed. The influence of gradient laser fields on erythrocyte rouleaus, on the apoptosis of human lymphocytes as well as on their chromosome aberrations is demonstrated. It may be concluded from the experimental studies that the influence of an interference laser field with a rightly chosen period can stimulate the repair system of a cell, increasing its viability

UV laser incorporation of dopants in silicon: comparison of two processes

International Nuclear Information System (INIS)

Fogarassy, E.P.; Narayan, J.; Lowndes, D.H.; White, C.H.

1985-01-01

The rapid deposition of pulsed-laser energy into the near-surface region of silicon leads to melting of crystal, followed by liquid phase epitaxial regrowth from the underlying substrate at a growth velocity of several meters per second. During rapid solidification, implanted or deposited group III and V impurities can be incorporated into substitutional sites in the silicon lattice with concentrations far in excess of their equilibrium solubility limit. The authors have investigated and compared the incorporation of implanted or deposited antimony into the silicon lattice during laser annealing with a pulsed KrF UV laser (lambda = 0.249 μm, Z = 35 ns). The surface melting dynamics resulting from laser irradiation have been studied by time-resolved reflectivity. In the two cases, the sharp transition to the high reflectivity phase (R = 72%, at lambda = 0.633 μm of the HeNe laser probe) is characteristic of molten silicon. Surface melt durations measured on implanted Sb (150 KeV, 5 x 10 16 cm -2 ) and deposited Sb (80 A thick on crystalline silicon) are significantly larger than those for virgin silicon

Influence of He-Ne laser irradiation of soybean seeds on seed mycoflora, growth, nodulation, and resistance to Fusarium solani

International Nuclear Information System (INIS)

Ouf, S.A.; Abdel-Hady, N.F.

1999-01-01

Laser irradiation of soybean seeds for 3 min caused a clear reduction in the number of seed-borne fungi which became more pronounced as the irradiation time was extended. Pretreatment of the seeds with methylene blue, methyl red and carmine enhanced the effect of laser. Rhizoctonia solani, Alternaria tenuissima, Cercospora kikuchii and Colletotrichum truncatum were completely eliminated when the seeds were pretreated with a dye and irradiated for 10 min. Seed germination was stimulated on exposure of the seed to 1-min irradiation. Chlorophyll a, chlorophyll b and carotenoid content of developed plants differed, depending on the irradiation dose and dye treatment of the seeds. The number and dry mass of nodules were mostly greater (as compared to the corresponding control), when the seeds irradiated for 1 or 3 min were pretreated with methyl red, chlorophenol red, crystal violet and methylene blue. Irradiation of pre-sowing seeds greatly protected soybean stands against F. solani

Inter-comparison of cosmogenic in-situ 3He, 21Ne and 36Cl at low latitude along an altitude transect on the SE slope of the Kilimanjaro volcano (3°S, Tanzania)

Science.gov (United States)

Schimmelpfennig, I.; Williams, A.; Pik, R.; Burnard, P.; Niedermann, S.; Finkel, R. C.; Benedetti, L.; Schneider, B.

2010-12-01

Because the intensity and energy spectrum of the cosmic ray flux is affected by atmospheric depth and geomagnetic-field strength, cosmogenic nuclide production rates increase considerably with altitude and to a lesser degree with latitude. The scaling methods used to account for spatial variability in production rates assume that all cosmogenic nuclides have the same altitude dependence. In this study we evaluate whether the production rates of cosmogenic 36Cl, 3He and 21Ne change differently with altitude, which is plausible due to the different energy-thresholds of their production reactions. If so, nuclide-specific scaling factors would be required. Concentrations of the three cosmogenic nuclides were determined in mafic phenocrysts over an altitude transect between 1000 and 4300 m at Kilimanjaro volcano (3° S). Altitude-dependence of relative production rates was assessed in two ways: by determination of concentration ratios and by calculation of apparent exposure age ratios for all nuclide pairs. The latter accounts for characteristics of 36Cl that the stable nuclides 3He and 21Ne do not possess (radioactive decay, high sensitivity to mineral composition and significant contributions from production reactions other than spallation). All ratios overlap within error over the entire transect, and altitudinal variation in relative production rates is not therefore evident. This suggests that nuclide-specific scaling factors are not required for the studied nuclides at this low latitude location. However, because previous studies [1,2] documented anomalous altitude-dependent variations of 3He production at mid-latitude sites, the effect of latitude on cross-calibrations should be further evaluated. We determined cosmogenic 21Ne/3He concentration ratios of 0.187 ± 0.010 in pyroxenes and 0.375 ± 0.015 in olivines, agreeing with those reported in previous studies. Despite the absence of independently determined ages for the studied lava surfaces, the consistency in

Long life gas laser system and method

International Nuclear Information System (INIS)

Hochuli, E.E.

1975-01-01

A long life gas discharge laser having an improved self-repairing cathode system is described. In a specific embodiment, water vapor having a partial pressure below about 10 -5 torr incorporated in a molecular sieve is used to provide impurities (in this case water vapor) for repairing the cathode surface by regenerating the oxide surface and/or preventing same from deteriorating. Other impurities may be incorporated in the molecular sieve such as hydrogen, oxygen, for example. In some cases CO 2 may be used. This application includes material disclosed in a paper entitled ''Continuation of the Investigation into Material Properties Affecting the Frequency Stability and Reliability of He-Ne Laser Structures'' submitted to the Office of Naval Research dated June 1972 by the inventor hereof and also a paper entitled ''Investigations of the Long Term Frequency Stability of Stable Laser Structures'' Progress Report for ONR Contract N00014-67-A-D239-0016 July 1972 by the inventor hereof. A royalty free license is hereby granted to the United States for use of the invention for all government purposes. (auth)

Development of a heterodyne laser interferometer for very small high frequency displacements detection

International Nuclear Information System (INIS)

Baarmann, P.

1992-10-01

A heterodyne laser interferometer with detection electronics has been developed for measuring very small amplitude high frequency vibrations. A laser beam from HeNe-laser is focused and reflected in the vibrating surface and the generated phase shifts are after interference with a reference beam detected with a photo detector and evaluated in a demodulation system. The set-up is a prototype and techniques to improve the accuracy and sensitivity of the system are presented. The present system can detect vibration amplitude from around 1 Angstrom and is linear up to 250 Angstrom (±4%). Frequencies from a few tens of kHz up to tens of MHz are covered. The low frequency region can be greatly improved. The minimum detectable displacement may be improved by narrowing the bandwidth of the detection system to the region of interest

Third-order nonlinear optical studies of anthraquinone dyes using a CW He–Ne laser

International Nuclear Information System (INIS)

Pramodini, S; Poornesh, P

2014-01-01

We present investigations on the third-order optical nonlinearity and optical power limiting of anthraquinone dyes. Z-scan measurements were performed using a continuous wave He–Ne laser at 633 nm wavelength as an excitation source. The nonlinear refraction studies exhibited self-defocusing behavior of the dyes. The nonlinear absorption in the dyes was dominated by a reverse saturable absorption process. Self-diffraction ring patterns were observed due to the change in refractive index and thermal lensing. Increase of the electron donating ability of the substituents resulted in enhanced values of the nonlinear optical parameters, establishing the structure–property relationship. The optical limiting study revealed that the dyes possess a lower limiting threshold and clamping level which is very important for eye and sensor protection. Hence, the dyes investigated here emerge as promising candidates for future opto-electronic and photonic device applications such as optical power limiters. (paper)

One-electron capture and target ionization in He+-neutral-atom collisions

International Nuclear Information System (INIS)

Shevelko, V.P.; Tolstikhina, I.Yu.; Kato, D.; Tawara, H.; Song, M-.Y.; Yoon, J-.S.

2009-12-01

One-electron capture and target-ionization cross sections in collisions of He + ions with neutral atoms: He + + A → He + A + and He + + A → He + + A + + e, A = H, He(1s 2 , 1s2s), Ne, Ar, Kr, Xe, are calculated and compared with available experimental data over the broad energy range E = 0.1 keV/u - 10 MeV/u of He + ions. The role of the metastable states of neutral helium atoms in such collisions, which are of importance in plasma physics applications, is briefly discussed. The recommended cross section data for these processes are presented in a closed analytical form (nine-order polynomials) which can be used for a plasma modeling and diagnostics. (author)

The observation of the Ne-like ion resonance line satellites for CrXV. Ni XIX CO[sub 2]-laser produced plasma

Energy Technology Data Exchange (ETDEWEB)

Khakhalin, S.Ya. (MISDC, NPO ' ' VNIIFTRI' ' , Mendeleevo (Russian Federation)); Faenov, A.Ya. (MISDC, NPO ' ' VNIIFTRI' ' , Mendeleevo (Russian Federation)); Skobelev, I.Yu. (MISDC, NPO ' ' VNIIFTRI' ' , Mendeleevo (Russian Federation)); Pikuz, S.A. (P. N. Lebedev Physical Inst., Russian Academy of Science, Moscow (Russian Federation)); 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 Ne-like ion resonance lines for elements from Cr to Ni. For these low-Z elements, we use spectra from strongly underionized CO[sub 2]-laser produced plasma to minimize the emission from open L-shell ions. This simplifies the spectra and allows the identification of satellite lines caused by radiative transitions from autoionizing states of sodium like ions. Good agreement between the satellite structure calculations and the experimental emission spectra is obtained. (orig.).

Laser effects on the growth and photosynthesis process in mustard plants (Sinapis Alba)

Science.gov (United States)

Anghel, Sorin; Stanescu, Constantin S.; Giosanu, Dana; Flenacu, Monica; Iorga-Siman, Ion

2001-06-01

In this paper we present the results of our experiments concerning the influence of the low energy laser (LEL) radiation on the germination, growth and photosyntheses processes in mustard plants (sinapis alba). We used a He-Ne laser ((lambda) equals 632.8 nm, P equals 6 mW) to irradiate the mustard seeds with different exposure times. The seeds were sowed and some determinations (the germination and growth intensity, chlorophyll quantity, and respiration intensity) were made on the plant culture. We ascertained that the germination and growth of the plants are influenced by the irradiation. Also, the chlorophyll quantity is the same for both plants from irradiated and non-irradiated seeds but the respiration and photosynthesis processes are influenced by the irradiation.

Multistage plasma initiation process by pulsed CO2 laser irradiation of a Ti sample in an ambient gas (He, Ar, or N2)

Science.gov (United States)

Hermann, J.; Boulmer-Leborgne, C.; Mihailescu, I. N.; Dubreuil, B.

1993-02-01

New experimental results are reported on plasma initiation in front of a titanium sample irradiated by ir (λ=10.6 μm) laser pulses in an ambient gas (He, Ar, and N2) at pressures ranging from several Torr up to the atmosphere. The plasma is studied by space- and time-resolved emission spectroscopy, while sample vaporization is probed by laser-induced fluorescence spectroscopy. Threshold laser intensities leading to the formation of a plasma in the vapor and in the ambient gases are determined. Experimental results support the model of a vaporization mechanism for the plasma initiation (vaporization-initiated plasma breakdown). The plasma initiation is described by simple numerical criteria based on a two-stage process. Theoretical predictions are found to be in a reasonable agreement with the experiment. This study provides also a clear explanation of the influence of the ambient gas on the laser beam-metal surface energy transfer. Laser irradiation always causes an important vaporization when performed in He, while in the case of Ar or N2, the interaction is reduced in heating and vaporization of some surface defects and impurities.

Caltech water-ice dusty plasma: preliminary results

Science.gov (United States)

Bellan, Paul; Chai, Kilbyoung

2013-10-01

A water-ice dusty plasma laboratory experiment has begun operation at Caltech. As in Ref., a 1-5 watt parallel-plate 13.56 MHz rf discharge plasma has LN2-cooled electrodes that cool the neutral background gas to cryogenic temperatures. However, instead of creating water vapor by in-situ deuterium-oxygen bonding, here the neutral gas is argon and water vapor is added in a controlled fashion. Ice grains spontaneously form after a few seconds. Photography with a HeNe line filter of a sheet of HeNe laser light sheet illuminating a cross section of dust grains shows a large scale whorl pattern composed of concentric sub-whorls having wave-like spatially varying intensity. Each sub-whorl is composed of very evenly separated fine-scale stream-lines indicating that the ice grains move in self-organized lanes like automobiles on a multi-line highway. HeNe laser extinction together with an estimate of dust density from the intergrain spacing in photographs indicates a 5 micron nominal dust grain radius. HeNe laser diffraction patterns indicate the ice dust grains are large and ellipsoidal at low pressure (200 mT) but small and spheroidal at high pressure (>600 mT). Supported by USDOE.

Development of quasi-monochromatic p-7Li neutron generating system for 80-210 MeV

International Nuclear Information System (INIS)

Nakao, Noriaki; Shibata, Tokushi; Nakamura, Takashi; Uwamino, Yoshitomo; Nakanishi, Noriyoshi; Kurosawa, Tadahiro; Kim, Unju.

1996-01-01

Recently the requirements for the experimental data on the response characteristics of neutron detector and the cross section for neutron generation by charged particles have been increasing for shield designing. Here, a system for quasi-monochromatic neutron generation was developed in the facility of ring-cyclotron in Institute of Physical and Chemical Sciences. In this study, H 2 + accelerated to an energy range of 80-135 MeV/n and P + to 150-210 MeV was irradiated to E4 beam course and NE102A plastic scintillator was used for monitoring the neutron flux. The amount of neutrons generated was estimated from the radioactivity of 7 Be produced in 7 Li-target. The neutron spectres thus estimated as an energy range of 80-210 MeV were presented and the lower limit of these spectres was about 20 MeV. The peaks in the range of 150 and 210 MeV were comparatively wide because of the inferiority of energy resolving power at a higher energy level. (M.N.)

Tracking frequency laser distance gauge

International Nuclear Information System (INIS)

Phillips, J.D.; Reasenberg, R.D.

2005-01-01

Advanced astronomical missions with greatly enhanced resolution and physics missions of unprecedented accuracy will require laser distance gauges of substantially improved performance. We describe a laser gauge, based on Pound-Drever-Hall locking, in which the optical frequency is adjusted to maintain an interferometer's null condition. This technique has been demonstrated with pm performance. Automatic fringe hopping allows it to track arbitrary distance changes. The instrument is intrinsically free of the nm-scale cyclic bias present in traditional (heterodyne) high-precision laser gauges. The output is a radio frequency, readily measured to sufficient accuracy. The laser gauge has operated in a resonant cavity, which improves precision, can suppress the effects of misalignments, and makes possible precise automatic alignment. The measurement of absolute distance requires little or no additional hardware, and has also been demonstrated. The proof-of-concept version, based on a stabilized HeNe laser and operating on a 0.5 m path, has achieved 10 pm precision with 0.1 s integration time, and 0.1 mm absolute distance accuracy. This version has also followed substantial distance changes as fast as 16 mm/s. We show that, if the precision in optical frequency is a fixed fraction of the linewidth, both incremental and absolute distance precision are independent of the distance measured. We discuss systematic error sources, and present plans for a new version of the gauge based on semiconductor lasers and fiber-coupled components

Development of a 3He nuclear spin flip system on an in-situ SEOP 3He spin filter and demonstration for a neutron reflectometer and magnetic imaging technique

International Nuclear Information System (INIS)

Hayashida, H; Kira, H; Miyata, N; Akutsu, K; Mizusawa, M; Parker, J D; Matsumoto, Y; Oku, T; Sakai, K; Hiroi, K; Shinohara, T; Takeda, M; Yamazaki, D; Oikawa, K; Harada, M; Ino, T; Imagawa, T; Ohkawara, M; Ohoyama, K; Kakurai, K

2016-01-01

We have been developing a 3 He neutron spin filter (NSF) using the spin exchange optical pumping (SEOP) technique. The 3 He NSF provides a high-energy polarized neutron beam with large beam size. Moreover the 3 He NSF can work as a π-flipper for a polarized neutron beam by flipping the 3 He nuclear spin using a nuclear magnetic resonance (NMR) technique. For NMR with the in-situ SEOP technique, the polarization of the laser must be reversed simultaneously because a non-reversed laser reduces the polarization of the spin-flipped 3 He. To change the polarity of the laser, a half-wavelength plate was installed. The rotation angle of the half-wavelength plate was optimized, and a polarization of 97% was obtained for the circularly polarized laser. The 3 He polarization reached 70% and was stable over one week. A demonstration of the 3 He nuclear spin flip system was performed at the polarized neutron reflectometer SHARAKU (BL17) and NOBORU (BL10) at J-PARC. Off-specular measurement from a magnetic Fe/Cr thin film and magnetic imaging of a magnetic steel sheet were performed at BL17 and BL10, respectively. (paper)

An exciton approach to the excited states of two electron atoms. II Determination of spectroscopic parameters, polarizabilites and dispersion coefficients of H-, He, Li+, Be2+ and Ne8+

International Nuclear Information System (INIS)

Schipper, P.E.; Martire, B.

1985-01-01

The exciton model is applied quantitatively to a description of the excited states of representative members of the helium isoelectronic series; viz. H + , He, Li + , Be 2+ and Ne 8+ . The energies of the eight lowest excited states are in good agreement with experiment, for a relatively small (1s-4p) hydrogenic basis; the ground state is obtained with slightly less precision. Response properties including oscillator strengths, polarizabilites and dispersion interaction coefficients are also calculated. The method leads to particularly simple interpretations of the wave functions and the energies

Experiments on state selection and Penning ionisation with fast metastable rare gas atoms

International Nuclear Information System (INIS)

Kroon, J.P.C.

1985-01-01

This thesis describes experiments with metastable He/Ne atoms. The experiments are performed in a crossed beam machine. Two different sources are used for the production of metastable atoms: a source for the production of metastable atoms in the thermal energy range and a hollow cathode arc for the production of metastable atoms in the superthermal energy range (1-7 eV). The progress made in the use of the hollow cathode arc is described as well as the experimental set-up. The rare gas energy-level diagram is characterized by two metastable levels. By optical pumping it is possible to select a single metastable level, both for He and Ne. For the case of He this is done by a recently built He quenchlamp which selectively quenches the metastable 2 1 S level population. In the thermal energy range the quenching is complete; in the superthermal energy range the 2 1 S level population is only partly quenched. For the optical pumping of Ne* atoms a cw dye laser is used. New experiments have been started on the measurement, in a crossed beam machine, of the fluorescence caused by inelastic collisions where metastable atoms are involved. The He* + Ne system is used as a pilot study for these experiments. The He-Ne laser is based on this collision system. (Auth.)

Laser source for dimensional metrology: investigation of an iodine stabilized system based on narrow linewidth 633 nm DBR diode

Science.gov (United States)

Rerucha, Simon; Yacoot, Andrew; Pham, Tuan M.; Cizek, Martin; Hucl, Vaclav; Lazar, Josef; Cip, Ondrej

2017-04-01

We demonstrated that an iodine stabilized distributed Bragg reflector (DBR) diode based laser system lasing at a wavelength in close proximity to λ =633 nm could be used as an alternative laser source to the helium-neon lasers in both scientific and industrial metrology. This yields additional advantages besides the optical frequency stability and coherence: inherent traceability, wider optical frequency tuning range, higher output power and high frequency modulation capability. We experimentally investigated the characteristics of the laser source in two major steps: first using a wavelength meter referenced to a frequency comb controlled with a hydrogen maser and then on an interferometric optical bench testbed where we compared the performance of the laser system with that of a traditional frequency stabilized He-Ne laser. The results indicate that DBR diode laser system provides a good laser source for applications in dimensional (nano)metrology, especially in conjunction with novel interferometric detection methods exploiting high frequency modulation or multiaxis measurement systems.

Amplitude and polarization asymmetries in a ring laser

Science.gov (United States)

Campbell, L. L.; Buholz, N. E.

1971-01-01

Asymmetric amplitude effects between the oppositely directed traveling waves in a He-Ne ring laser are analyzed both theoretically and experimentally. These effects make it possible to detect angular orientations of an inner-cavity bar with respect to the plane of the ring cavity. The amplitude asymmetries occur when a birefringent bar is placed in the three-mirror ring cavity, and an axial magnetic field is applied to the active medium. A simplified theoretical analysis is performed by using a first order perturbation theory to derive an expression for the polarization of the active medium, and a set of self-consistent equations are derived to predict threshold conditions. Polarization asymmetries between the oppositely directed waves are also predicted. Amplitude asymmetries similar in nature to those predicted at threshold occur when the laser is operating in 12-15 free-running modes, and polarization asymmetry occurs simultaneously.

Long-range interactions of excited He atoms with ground-state noble-gas atoms

KAUST Repository

Zhang, J.-Y.; Qian, Ying; Schwingenschlö gl, Udo; Yan, Z.-C.

2013-01-01

The dispersion coefficients C6, C8, and C10 for long-range interactions of He(n1,3S) and He(n1,3P), 2≤n≤10, with the ground-state noble-gas atoms Ne, Ar, Kr, and Xe are calculated by summing over the reduced matrix elements of multipole transition

Towards non-sequential double ionization of Ne and Ar using a femtosecond laser oscillator.

Science.gov (United States)

Liu, Yunquan; Tschuch, Sebastian; Dürr, Martin; Rudenko, Artem; Moshammer, Robert; Ullrich, Joachim; Siegel, Martin; Morgner, Uwe

2007-12-24

We report on first proof-of-principles results on non-sequential double ionization of argon and neon achieved by using a newly developed long-cavity Ti:sapphire femtosecond oscillator with a pulse duration of 45 fs and a repetition of 6.2 MHz combined with a dedicated reaction microscope. Under optimized experimental conditions, peak intensities larger than 2.310(14) W/cm(2) have been achieved. Ion momentum distributions were recorded for both rare gases and show significantly different features for single as well as for double ionization. For single ionization of neon a spike of zero-momentum electrons is found when decreasing the laser intensity towards the lowest ionization rate we can measure which is attributed to a non-resonant ionization channel. As to double ionization, the longitudinal momentum distribution for Ne(2+) displays a clear double-hump structure whereas this feature is found to be smoothened out with a maximum at zero momentum for Ar(2+).

A laser scanner for imaging fluorophore labeled molecules in electrophoretic gels

Energy Technology Data Exchange (ETDEWEB)

Fisk, D.J.; Sutherland, J.C. [Brookhaven National Lab., Upton, NY (United States). Biology Dept.

1995-08-01

A laser scanner for imaging electrophoretic gels was constructed and tested. The scanner incorporates a green helium-neon (HeNe) laser (543.5nm wavelength) and can achieve a spatial resolution of 19{micro}m. The instrument can function in two modes : snap-shot and finish-line. In snapshot mode, all samples are electrophoresed for the same time and the gel is scanned after completion of electrophoresis, while in finish-line mode, fluorophore labeled samples are electrophoresed for a constant distance and the image is formed as the samples pass under the detector. The resolving power of the finish-line mode of imaging is found to be greater than that of the snapshot mode of imaging. This laser scanner is also compared with a Charge Coupled Device (CCD) camera and in terms of resolving power is found to be superior. Sensitivity of the instrument is presented in terms of the minimum amount of DNA that can be detected verses its molecular length.

Effect of seed treatment with low-potency laser in peppers plants (Capsicum annuum L.

Directory of Open Access Journals (Sweden)

Alexander Álvarez Fonseca,

2014-01-01

Full Text Available The influence of seed treatment with low-potency laser radiation on some physiological parameters and yield of peppers plants, California Wonder variety, was studied. The seeds were irradiated with a laser He- Ne, 25 mW powers, at different exposure periods 5, 10, 20, 30 and 60 seconds, using untreated seeds as controls. We evaluated plant height (mm, root length (mm, stem diameter (mm, polar average diameter (mm equatorial mean diameter (mm, mean fruit mass (g and yield per plant (kg.plant-1. The results showed a significant increase (p?0.001 in the indicators of plants height (50 %, root length (13 %, stem diameter (17 %, equatorial mean diameter (7 %, mean fruit mass (13 % and yield per plant (67 %, compared to control.

Frequency stabilization of a 1083 nm fiber laser to {sup 4}He transition lines with optical heterodyne saturation spectroscopies

Energy Technology Data Exchange (ETDEWEB)

Gong, W.; Peng, X., E-mail: xiangpeng@pku.edu.cn; Li, W.; Guo, H., E-mail: hongguo@pku.edu.cn [State Key Laboratory of Advanced Optical Communication Systems and Networks, School of Electronics Engineering and Computer Science, Center for Quantum Information Technology, and Center for Computational Science and Engineering (CCSE), Peking University, Beijing 100871 (China)

2014-07-15

Two kinds of optical heterodyne saturation spectroscopies, namely, frequency modulation spectroscopy (FMS) and modulation transfer spectroscopy (MTS), are demonstrated for locking a fiber laser to the transition lines of metastable {sup 4}He atoms around 1083 nm. The servo-loop error signals of FMS and MTS for stabilizing laser frequency are optimized by studying the dependence of the peak-to-peak amplitude and slope on the optical power of pump and probe beams. A comparison of the stabilization performances of FMS/MTS and polarization spectroscopy (PS) is presented, which shows that MTS exhibits relatively superior performance with the least laser frequency fluctuation due to its flat-background dispersive signal, originated from the four-wave mixing process. The Allan deviation of the stabilized laser frequency is 5.4 × 10{sup −12}@100 s with MTS for data acquired in 1000 s, which is sufficiently applicable for fields like laser cooling, optical pumping, and optical magnetometry.

Measurement of sup 15 O(. alpha. ,. gamma. ) sup 19 Ne resonance strengths

Energy Technology Data Exchange (ETDEWEB)

Magnus, P V; Smith, M S; Howard, A J; Parker, P D [Yale Univ., New Haven, CT (USA). Nuclear Structure Lab.; Champagne, A E [Princeton Univ., NJ (USA). Dept. of Physics

1990-01-08

States in {sup 19}Ne above the {sup 15}O+{alpha} threshold were populated by means of the {sup 19}F({sup 3}He,t){sup 19}Ne* reaction, and their alpha-particle decays to the {sup 15}O ground state were measured. The branching ratios {Gamma}{sub {alpha}}/{Gamma}{sub total} for the E{sub c.m.}=850-, 1020-, 1971-, 1183- and 1563-keV resonances in {sup 15}O+{alpha} were determined. This information together with alpha-particle and/or gamma-ray partial widths (determined from knowledge of these quantities for the mirror states in {sup 19}F) determines the strengths of these {sup 15}O({alpha},{gamma}){sup 19}Ne resonances and the {sup 15}O({alpha},{gamma}){sup 19}Ne reaction rate for temperatures between 7x10{sup 8} and 3x10{sup 9} K. (orig.).

COMPARISON OF RETINAL PATHOLOGY VISUALIZATION IN MULTISPECTRAL SCANNING LASER IMAGING.

Science.gov (United States)

Meshi, Amit; Lin, Tiezhu; Dans, Kunny; Chen, Kevin C; Amador, Manuel; Hasenstab, Kyle; Muftuoglu, Ilkay Kilic; Nudleman, Eric; Chao, Daniel; Bartsch, Dirk-Uwe; Freeman, William R

2018-03-16

To compare retinal pathology visualization in multispectral scanning laser ophthalmoscope imaging between the Spectralis and Optos devices. This retrospective cross-sectional study included 42 eyes from 30 patients with age-related macular degeneration (19 eyes), diabetic retinopathy (10 eyes), and epiretinal membrane (13 eyes). All patients underwent retinal imaging with a color fundus camera (broad-spectrum white light), the Spectralis HRA-2 system (3-color monochromatic lasers), and the Optos P200 system (2-color monochromatic lasers). The Optos image was cropped to a similar size as the Spectralis image. Seven masked graders marked retinal pathologies in each image within a 5 × 5 grid that included the macula. The average area with detected retinal pathology in all eyes was larger in the Spectralis images compared with Optos images (32.4% larger, P < 0.0001), mainly because of better visualization of epiretinal membrane and retinal hemorrhage. The average detection rate of age-related macular degeneration and diabetic retinopathy pathologies was similar across the three modalities, whereas epiretinal membrane detection rate was significantly higher in the Spectralis images. Spectralis tricolor multispectral scanning laser ophthalmoscope imaging had higher rate of pathology detection primarily because of better epiretinal membrane and retinal hemorrhage visualization compared with Optos bicolor multispectral scanning laser ophthalmoscope imaging.

Nucleogenic production of Ne isotopes in Earth's crust and upper mantle induced by alpha particles from the decay of U and Th

Science.gov (United States)

Leya, Ingo; Wieler, Rainer

1999-07-01

The production of nucleogenic Ne in terrestrial crust and upper mantle by alpha particles from the decay of U and Th was calculated. The calculations are based on stopping powers for the chemical compounds and thin-target cross sections. This approach is more rigorous than earlier studies using thick-target yields for pure elements, since our results are independent of limiting assumptions about stopping-power ratios. Alpha induced reactions account for >99% of the Ne production in the crust and for most of the 20,21Ne in the upper mantle. On the other hand, our 22Ne value for the upper mantle is a lower limit because the reaction 25Mg(n,α)22Ne is significant in mantle material. Production rates calculated here for hypothetical crustal and upper mantle material with average major element composition and homogeneously distributed F, U, and Th are up to 100 times higher than data presented by Kyser and Rison [1982] but agree within error limits with the results by Yatsevich and Honda [1997]. Production of nucleogenic Ne in "mean" crust and mantle is also given as a function of the weight fractions of O and F. The alpha dose is calculated by radiogenic 4He as well as by the more retentive fissiogenic 136Xe. U and Th is concentrated in certain accessory minerals. Since the ranges of alpha particles from the three decay chains are comparable to mineral dimensions, most nucleogenic Ne is produced in U- and Th-rich minerals. Therefore nucleogenic Ne production in such accessories was also calculated. The calculated correlation between nucleogenic 21Ne and radiogenic 4He agrees well with experimental data for Earth's crust and accessories. Also, the calculated 22Ne/4He ratios as function of the F concentration and the dependence of 21Ne/22Ne from O/F for zircon and apatite agree with measurements.

Effect of liquid film on near-threshold laser ablation of a solid surface

Energy Technology Data Exchange (ETDEWEB)

Kim, Dongsik; Oh, Bukuk; Lee, Ho

2004-01-30

Enhancement of material ablation and photoacoustic excitation by an artificially deposited liquid film in the process of pulsed-laser ablation (PLA) is investigated in this paper. Ablation threshold, ablation rate, surface topography, and acoustic-transient emission are also measured for dry and liquid film-coated surfaces. The physical mechanisms of enhanced ablation in the liquid-assisted process are analyzed at relatively low laser fluences with negligible effect of laser-produced plasma. Particularly, correlation between material ablation and acoustic-transient generation is examined. In the experiment, aluminum thin-films and bulk foils are ablated by Q-switched Nd:YAG laser pulses. The dependence of ablation rate and laser-induced topography on liquid film thickness and chemical composition is also examined. Photoacoustic emission is measured by the probe beam deflection method utilizing a CW HeNe laser and a microphone. In comparison with a dry ablation process, the liquid-assisted ablation process results in substantially augmented ablation efficiency and reduced ablation threshold. The results indicate that both increased laser-energy coupling, i.e., lowered reflectance, and amplified photoacoustic excitation in explosive vaporization of liquid are responsible for the enhanced material ablation.

Synthesizing monochromatic 3-D images by multiple-exposure rainbow holography with vertical area-partition approach

Institute of Scientific and Technical Information of China (English)

翟宏琛; 王明伟; 刘福民; 母国光

2002-01-01

We report for the first time the theoretical analysis and experimental results of a white-light reconstructed monochromatic 3-D image synthesizing tomograms by multiple rainbow holo-graphy with vertical-area partition (VAP) approach. The theoretical and experimental results show that 3-D monochromatic image can be synthesized by recording the master hologram by VAP ap-proach without any distortions either in gray scale or in geometrical position. A 3-D monochromatic image synthesized from a series of medical tomograms is presented in this paper for the first time.

Solar cycle variation of interstellar neutral He, Ne, O density and pick-up ions along the Earth's orbit

Science.gov (United States)

Sokół, Justyna M.; Bzowski, Maciej; Kubiak, Marzena A.; Möbius, Eberhard

2016-06-01

We simulated the modulation of the interstellar neutral (ISN) He, Ne, and O density and pick-up ion (PUI) production rate and count rate along the Earth's orbit over the solar cycle (SC) from 2002 to 2013 to verify if SC-related effects may modify the inferred ecliptic longitude of the ISN inflow direction. We adopted the classical PUI model with isotropic distribution function and adiabatic cooling, modified by time- and heliolatitude-dependent ionization rates and non-zero injection speed of PUIs. We found that the ionization losses have a noticeable effect on the derivation of the ISN inflow longitude based on the Gaussian fit to the crescent and cone peak locations. We conclude that the non-zero radial velocity of the ISN flow and the energy range of the PUI distribution function that is accumulated are of importance for a precise reproduction of the PUI count rate along the Earth orbit. However, the temporal and latitudinal variations of the ionization in the heliosphere, and particularly their variation on the SC time-scale, may significantly modify the shape of PUI cone and crescent and also their peak positions from year to year and thus bias by a few degrees the derived longitude of the ISN gas inflow direction.

Periprosthetic Artifact Reduction Using Virtual Monochromatic Imaging Derived From Gemstone Dual-Energy Computed Tomography and Dedicated Software.

Science.gov (United States)

Reynoso, Exequiel; Capunay, Carlos; Rasumoff, Alejandro; Vallejos, Javier; Carpio, Jimena; Lago, Karen; Carrascosa, Patricia

2016-01-01

The aim of this study was to explore the usefulness of combined virtual monochromatic imaging and metal artifact reduction software (MARS) for the evaluation of musculoskeletal periprosthetic tissue. Measurements were performed in periprosthetic and remote regions in 80 patients using a high-definition scanner. Polychromatic images with and without MARS and virtual monochromatic images were obtained. Periprosthetic polychromatic imaging (PI) showed significant differences compared with remote areas among the 3 tissues explored (P remote tissues using monochromatic imaging with MARS (P = 0.053 bone, P = 0.32 soft tissue, and P = 0.13 fat). However, such differences were significant using PI with MARS among bone (P = 0.005) and fat (P = 0.02) tissues. All periprosthetic areas were noninterpretable using PI, compared with 11 (9%) using monochromatic imaging. The combined use of virtual monochromatic imaging and MARS reduced periprosthetic artifacts, achieving attenuation levels comparable to implant-free tissue.

EXPLORING THE POSSIBILITY OF O AND Ne CONTAMINATION IN ULYSSES OBSERVATIONS OF INTERSTELLAR HELIUM

International Nuclear Information System (INIS)

Wood, Brian E.; Müller, Hans-Reinhard; Bzowski, Maciej; Sokół, Justyna M.; Möbius, Eberhard; Witte, Manfred; McComas, David J.

2015-01-01

We explore the possibility that interstellar O and Ne may be contributing to the particle signal from the GAS instrument on Ulysses, which is generally assumed to be entirely He. Motivating this study is the recognition that an interstellar temperature higher than any previously estimated from Ulysses data could potentially resolve a discrepancy between Ulysses He measurements and those from the Interstellar Boundary Explorer (IBEX). Contamination by O and Ne could lead to Ulysses temperature measurements that are too low. We estimate the degree of O and Ne contamination necessary to increase the inferred Ulysses temperature to 8500 K, which would be consistent with both the Ulysses and IBEX data given the same interstellar flow speed. We find that producing the desired effect requires a heavy element contamination level of ∼9% of the total Ulysses/GAS signal. However, this degree of heavy element contribution is about an order of magnitude higher than expected based on our best estimates of detection efficiencies, ISM abundances, and heliospheric survival probabilities, making it unlikely that heavy element contamination is significantly affecting temperatures derived from Ulysses data

EXPLORING THE POSSIBILITY OF O AND Ne CONTAMINATION IN ULYSSES OBSERVATIONS OF INTERSTELLAR HELIUM

Energy Technology Data Exchange (ETDEWEB)

Wood, Brian E. [Naval Research Laboratory, Space Science Division, Washington, DC 20375 (United States); Müller, Hans-Reinhard [Department of Physics and Astronomy, Dartmouth College, Hanover, NH 03755 (United States); Bzowski, Maciej; Sokół, Justyna M. [Space Research Centre of the Polish Academy of Sciences, Ul. Bartycka 18 A, 00-716 Warsaw (Poland); Möbius, Eberhard [Space Science Center and Department of Physics, University of New Hampshire, Durham, NH 03824 (United States); Witte, Manfred [Max-Planck-Institute for Solar System Research, Katlenburg-Lindau (Germany); McComas, David J., E-mail: brian.wood@nrl.navy.mil [Southwest Research Institute, San Antonio, TX 78228 (United States)

2015-10-15

We explore the possibility that interstellar O and Ne may be contributing to the particle signal from the GAS instrument on Ulysses, which is generally assumed to be entirely He. Motivating this study is the recognition that an interstellar temperature higher than any previously estimated from Ulysses data could potentially resolve a discrepancy between Ulysses He measurements and those from the Interstellar Boundary Explorer (IBEX). Contamination by O and Ne could lead to Ulysses temperature measurements that are too low. We estimate the degree of O and Ne contamination necessary to increase the inferred Ulysses temperature to 8500 K, which would be consistent with both the Ulysses and IBEX data given the same interstellar flow speed. We find that producing the desired effect requires a heavy element contamination level of ∼9% of the total Ulysses/GAS signal. However, this degree of heavy element contribution is about an order of magnitude higher than expected based on our best estimates of detection efficiencies, ISM abundances, and heliospheric survival probabilities, making it unlikely that heavy element contamination is significantly affecting temperatures derived from Ulysses data.

Low energy helium-neon laser prevents oral mucositis after high-dose chemo-radiotherapy: results of a double-blind randomized trial

International Nuclear Information System (INIS)

Cowen, Didier; Tardieu, Corinne; Resbeut, Michel; Hannoun-Levi, Jean-Michel; Alzieu, Claude; Schubert, Marc; Franquin, Jean-Claude

1996-01-01

Purpose: To evaluate the efficiency of Helium-Neon (He-Ne) laser in the prevention of oral mucositis (OM) induced by high dose chemoradiotherapy before bone marrow transplantation (BMT). Methods and materials: Between 1993 and 1995, 30 consecutive patients (pts) receiving an autologous peripheral stem-cell or bone marrow transplant (BMT) after high dose chemoradiotherapy were randomized to receive or not prophylactic laser applications to the oral mucosa. Chemotherapy consisted of cyclophosphamide, 60 mg/kg intravenously (IV) on day (d)-5 and d-4 in 27 cases, or melphalan 140 mg/kg IV on d-4 in 3 cases. Total body irradiation consisted of 12 Gy midplane dose in six fractions and 3 days. He-Ne laser (632.8 nm wavelength, power 60 mW) applications were performed daily from d-5 to d-1 on 5 anatomic sites of the oral mucosa. Oral examination was performed daily from d0 to d+20. Mucositis was scored according to an oral exam guide with a 16 items scale of which 4 were assessed by the pts themselves. Mean daily scores of pain, ability to swallow and saliva production were measured. A daily mucositis index (DMI) and a cumulative score of oral mucositis (CSOM) were established. Requirement for narcotics and parenteral nutrition were measured. Validation of the grading scale was carried out using the Cronbach alpha coefficient for the internal validation and the test-retest correlation coefficient for the reproducibility analysis. The U Mann Whitney test was used to test for differences among groups. Patients were assigned to either laser treatment (L+) or sham-treatment (L-) by computer blocked randomization. Results: No pt was excluded for failure to complete the laser application protocol. Laser applications were well tolerated and no side effects were reported. The items were highly interrelated as well as the index considered as a whole: over 21 days, α = 0.97. Reproducibility analysis between the nurses in charge with the oral examination showed a significant

Laser biostimulation of articular cartilage: in vitro evaluation

Science.gov (United States)

Jia, Yali; Guo, Zhouyi; Yang, Xiaohong; Zeng, Chang-Chun

2004-07-01

In the orthopaedic field, the repair of ariticular cartilage is still a difficult problem, because of the physiological characters of cartilaginous tissues and chondrocytes. To find an effective method of stimulating their regeneration, this in vitro study focuses on the biostimulation of rabbit articular chondrocytes by low-power He-Ne laser. The articular chondrocytes isolated from the cartilage of the medial condyle of the femur of the rabbit were incubated in HamF12 medium. The second passage culture were spread on 24 petri dishes and were irradiated with laser at power density of 2 - 12 mW/cm2 for 6.5 minutes, corresponding to the energy density of 1-6 J/cm2. Laser treatment was performed three times at a 24-hour interval. After lasering, incubation was continued for 24 hours. Non-irradiated cells were kept under the same conditions as the irradiated ones. The cell proliferation activity was evaluated with a XTT colorimetric method. Irradiation of 4 - 6 J/cm2 revealed a considerably higher cell proliferation activity comparing to control cultures. Thereinto, the energy density of 4 and 5 J/cm2 remarkably increased cell growth (P<0.01). The present study showed that a particular laser irradiation stimulates articular chondrocytes proliferation. These findings might be clinically relevant, indicating that low-power laser irradiation treatment is likely to achieve the repair of articular cartilage in clinic.

Double capture in the O8+ + He collision investigated by electron spectroscopy (80 keV, 10 deg)

International Nuclear Information System (INIS)

Moretto-Capelle, P.; Benoit-Cattin, P.; Bordenave-Montesquieu, A.; Boudjema, M.; Gleizes, A.; Dousson, S.; Hitz, D.

1989-01-01

Double capture into (3,n) autoionising states of O 6+ is observed in the O 8+ + He collision system by electron spectroscopy at 80 keV, 10 0 . A comparison of the experimental results with theoretical positions and lifetimes allows the (3,3) states as well as three groups of (3,4) states to be identified. The present experimental findings are compared with earlier data for the N 7+ + He and Ne 8+ (1s 2 ) + He systems. The influence of the core of the multicharged ion is studied by examining the O 8+ and Ne 8+ (1s 2 ) results. The total double capture cross section is found to be large and it is compared with available experimental and theoretical data. (author)

Comparison of UV action spectra for lethality and mutation in Salmonella typhimurium using a broad band source and monochromatic radiations

International Nuclear Information System (INIS)

Calkins, John; Selby, Christopher; Enoch, H.G.

1987-01-01

The UV-B region (280-320 nm) is thought to be primarily responsible for the mutagenic, lethal, and carcinogenic effects of solar radiation. We have conducted UV-B action spectroscopy for mutagenesis and survival of Ames' Salmonella typhimurium strain TA98 (uvrB, pKM101) using both monochromatic radiation from a dye laser and broader bandwidth radiation emitted from FS-20 sunlamps. A series of optical filters having different transmission cut-offs together with the sunlamp source provided bandwidths having successively less short wavelength components from which a ''broad band'' action spectrum was deduced. The two sets of action spectra differed both qualitatively and quantitatively: in comparison to the monochromatic action spectra, the ''broad band'' spectra showed up to a 200-fold reduced efficiency for both mutation induction and lethality by UV-B wavelengths. These results suggest a large protective effect of the background UV-A and/or visible radiations which were present during the broad spectrum irradiations and which are also present in solar radiation. Additional experiments show that to the extent tested this protective effect is not due to photo-reactivation or irradiance (dose rate) effects. (author)

The possibility of lasing in Ne+Ar ionic molecules pumped by a hard ioniser

International Nuclear Information System (INIS)

Boichenko, Aleksandr M; Yakovlenko, Sergei I

2000-01-01

The kinetic model of relaxation in the Ne-Ar-Kr mixture pumped by a hard ioniser is constructed in connection with the analysis of the possibility of lasing at the Ne + Ar→NeAr + transition of the inert-gas ionic exciplexes. The calculations based on the typical rates of plasmachemical reactions demonstrate that the lasing is possible but difficult to realise: One needs high pressures (greater than 16 bar) and high pumping densities (∼ 1 MW cm -3 ). In the most favourable cases, the laser efficiency lies between 0.05 and 0.25%. (active media)

The monochromatic imaging mode of a RITA-type neutron spectrometer

International Nuclear Information System (INIS)

Bahl, C.R.H.; Andersen, P.; Klausen, S.N.; Lefmann, K.

2004-01-01

The imaging monochromatic mode of a neutron spectrometer with a multi-bladed RITA analyser system is so far unexplored. We present analytical calculations that define the mode. It is shown that the mode can be realised for PG (0 0 2) analyser crystals, from incident energies of about 3.2 meV and up, allowing the important cases of 3.7, 5.0 and 13.7 meV. Due to beam divergence, the neutron rays from neighbouring analyser blades are found to overlap slightly. Hence, the optimal use of the monochromatic imaging mode would be found by employing an adjustable radial collimator to limit the spread of the ray from each analyser blade

The monochromatic imaging mode of a RITA-type neutron spectrometer

Energy Technology Data Exchange (ETDEWEB)

Bahl, C.R.H. [Department of Materials Research, Riso National Laboratory, Building 227, Frederiksborgvej 399, DK-4000 Roskilde (Denmark) and Department of Physics, Technical University of Denmark, DK-2800 Lyngby (Denmark)]. E-mail: christian.bahl@risoe.dk; Andersen, P. [Department of Materials Research, Riso National Laboratory, Building 227, Frederiksborgvej 399, DK-4000 Roskilde (Denmark); Niels Bohr Institute for Astronomy, Physics and Geophysics, University of Copenhagen, DK-2100 Copenhagen (Denmark); Klausen, S.N. [Department of Materials Research, Riso National Laboratory, Building 227, Frederiksborgvej 399, DK-4000 Roskilde (Denmark); Lefmann, K. [Department of Materials Research, Riso National Laboratory, Building 227, Frederiksborgvej 399, DK-4000 Roskilde (Denmark)

2004-12-01

The imaging monochromatic mode of a neutron spectrometer with a multi-bladed RITA analyser system is so far unexplored. We present analytical calculations that define the mode. It is shown that the mode can be realised for PG (0 0 2) analyser crystals, from incident energies of about 3.2 meV and up, allowing the important cases of 3.7, 5.0 and 13.7 meV. Due to beam divergence, the neutron rays from neighbouring analyser blades are found to overlap slightly. Hence, the optimal use of the monochromatic imaging mode would be found by employing an adjustable radial collimator to limit the spread of the ray from each analyser blade.

Laser-Electron-Gamma-Source. Progress report, July 1986

International Nuclear Information System (INIS)

Dowell, D.H.; Fineman, B.; Giordano, G.; Kistner, OC.; Matone, G.; Sandorfi, A.M.; Schaerf, C.; Thorn, C.E.; Ziegler, W.

1986-07-01

When completed, the Laser Electron Gamma Source (LEGS) is expected to provide intense beams of monochromatic and polarized (circular or linear) gamma rays with energies up to 500 MeV. The gamma-ray beams will be produced by Compton backscattering uv laser light from the electrons circulating in a storage ring. Progress with installation of the facility is described, particularly the Ar-ion laser and tagging spectrometer. Tests of the tagging spectrometer coponents is reported, and a second laser is described for higher energy operation. Estimates are given of expected beam parameters. Experimental equipment for the planned research projects to be carried out at the LEGS facility is discussed

Benefits of low-power lasers on oral soft tissue

Science.gov (United States)

Eduardo, Carlos d. P.; Cecchini, Silvia C. M.; Cecchini, Renata C.

1996-04-01

The last five years have represented a great advance in relation to laser development. Countries like Japan, United States, French, England, Israel and others, have been working on the association of researches and clinical applications, in the field of laser. Low power lasers like He-Ne laser, emitting at 632,8 nm and Ga-As-Al laser, at 790 nm, have been detached acting not only as a coadjutant but some times as an specific treatment. Low power lasers provide non thermal effect at wavelengths believed to stimulate circulation and cellular activity. These lasers have been used to promote wound healing and reduce inflammation edema and pain. This work presents a five year clinical study with good results related to oral tissue healing. Oral cavity lesions, like herpes and aphthous ulcers were irradiated with Ga-Al- As laser. In both cases, an excellent result was obtained. The low power laser application decrease the painful sintomatology immediately and increase the reparation process of these lesions. An excellent result was obtained with application of low power laser in herpetic lesions associated with a secondary infection situated at the lip commissure covering the internal tissue of the mouth. The healing occurred after one week. An association of Ga-Al-As laser and Nd:YAG laser have been also proven to be good therapy for these kind of lesions. This association of low and high power laser has been done since 1992 and it seems to be a complement of the conventional therapies.

Measurement of the spatial coherence of a soft x-ray laser

International Nuclear Information System (INIS)

Trebes, J.E.; Mrowka, S.; London, R.A.; Barbee, T.W.; Carter, M.R.; MacGowan, B.J.; Matthews, D.L.; Da Silva, L.B.; Stone, G.F.; Feit, M.D.; Nugent, K.A.

1991-01-01

The spatial coherence of a neon-like selenium x-ray laser operating at 206 and 210 Angstroems has been measured using a technique based on partially coherent x-ray diffraction. The time integrated spatial coherence of the selenium x-ray laser was determined to be equivalent to that of a quasi-monochromatic spatially incoherent disk source whose diameter is comparable to the line focus of the visible light laser pumping the x-ray laser. The spatial coherence was improved by narrowing the line focus width. 20 refs., 4 figs

Staged electron laser accelerator (STELLA) experiment at brookhaven ATF

Energy Technology Data Exchange (ETDEWEB)

Pogorelsky, I V; Steenbergen, A van; Gallardo, J C [Brookhaven National Lab., Upton, NY (United States); and others

1998-03-01

The STELLA experiment is being prepared at the BNL Accelerator Test Facility (STF). The goal of the experiment is to demonstrate quasi-monochromatic inverse Cherenkov acceleration (ICA) of electrons bunched to the laser wavelength period. Microbunches on the order of 2 {mu}m in length separated by 10.6 {mu}m will be produced using an inverse free electron laser (IFEL) accelerator driven by a CO{sub 2} laser. The design and simulations for two phases of this experiment including demonstration of 10 MeV and 100 MeV acceleration are presented. (author)

Long-range interactions of excited He atoms with ground-state noble-gas atoms

KAUST Repository

Zhang, J.-Y.

2013-10-09

The dispersion coefficients C6, C8, and C10 for long-range interactions of He(n1,3S) and He(n1,3P), 2≤n≤10, with the ground-state noble-gas atoms Ne, Ar, Kr, and Xe are calculated by summing over the reduced matrix elements of multipole transition operators. The large-n expansions for the sums over the He oscillator strength divided by the corresponding transition energy are presented for these series. Using the expansions, the C6 coefficients for the systems involving He(131,3S) and He(131,3P) are calculated and found to be in good agreement with directly calculated values.

Gersch-Rodriguez-Smith computation of deep inelastic electron scattering on 4He

International Nuclear Information System (INIS)

Viviani, M.; Kievsky, A.; Rinat, A.S.

2003-01-01

We compute cross sections for inclusive scattering of high-energy electrons on 4 He, based on the two lowest orders of the Gersch-Rodriguez-Smith series. The required one- and two-particle density matrices are obtained from nonrelativistic 4 He wave functions using realistic models for the nucleon-nucleon and three-nucleon interaction. The computed results for E=3.6 GeV agree well with the NE3 SLAC-Virginia data

The optimal monochromatic spectral computed tomographic imaging plus adaptive statistical iterative reconstruction algorithm can improve the superior mesenteric vessel image quality

Energy Technology Data Exchange (ETDEWEB)

Yin, Xiao-Ping; Zuo, Zi-Wei; Xu, Ying-Jin; Wang, Jia-Ning [CT/MRI room, Affiliated Hospital of Hebei University, Baoding, Hebei, 071000 (China); Liu, Huai-Jun, E-mail: hebeiliu@outlook.com [Department of Medical Imaging, The Second Hospital of Hebei Medical University, Shijiazhuang, Hebei, 050000 (China); Liang, Guang-Lu [CT/MRI room, Affiliated Hospital of Hebei University, Baoding, Hebei, 071000 (China); Gao, Bu-Lang, E-mail: browngao@163.com [Department of Medical Research, Shijiazhuang First Hospital, Shijiazhuang, Hebei, 050011 (China)

2017-04-15

Objective: To investigate the effect of the optimal monochromatic spectral computed tomography (CT) plus adaptive statistical iterative reconstruction on the improvement of the image quality of the superior mesenteric artery and vein. Materials and methods: The gemstone spectral CT angiographic data of 25 patients were reconstructed in the following three groups: 70 KeV, the optimal monochromatic imaging, and the optimal monochromatic plus 40%iterative reconstruction mode. The CT value, image noises (IN), background CT value and noises, contrast-to-noise ratio (CNR), signal-to-noise ratio (SNR) and image scores of the vessels and surrounding tissues were analyzed. Results: In the 70 KeV, the optimal monochromatic and the optimal monochromatic images plus 40% iterative reconstruction group, the mean scores of image quality were 3.86, 4.24 and 4.25 for the superior mesenteric artery and 3.46, 3.78 and 3.81 for the superior mesenteric vein, respectively. The image quality scores for the optimal monochromatic and the optimal monochromatic plus 40% iterative reconstruction groups were significantly greater than for the 70 KeV group (P < 0.05). The vascular CT value, image noise, background noise, CNR and SNR were significantly (P < 0.001) greater in the optimal monochromatic and the optimal monochromatic images plus 40% iterative reconstruction group than in the 70 KeV group. The optimal monochromatic plus 40% iterative reconstruction group had significantly (P < 0.05) lower image and background noise but higher CNR and SNR than the other two groups. Conclusion: The optimal monochromatic imaging combined with 40% iterative reconstruction using low-contrast agent dosage and low injection rate can significantly improve the image quality of the superior mesenteric artery and vein.

High-Resolution Spectroscopy of He{_2}^+ Using Rydberg-Series Extrapolation and Zeeman-Decelerated Supersonic Beams of Metastable He_2

Science.gov (United States)

Jansen, Paul; Semeria, Luca; Merkt, Frederic

2016-06-01

Having only three electrons, He{_2}^+ represents a system for which highly accurate ab initio calculations are possible. The latest calculations of rovibrational energies in He{_2}^+ do not include relativistic or QED corrections but claim an accuracy of 120 MHz We have performed high-resolution Rydberg spectroscopy of metastable He_2 molecules and employed multichannel-quantum-defect-theory extrapolation techniques to determine the rotational energy-level structure in the He{_2}^+ ion. To this end, we have produced samples of metastable helium molecules in supersonic beams with velocities tunable down to 100 m/s by combining a cryogenic supersonic-beam source with a multistage Zeeman decelerator. The metastable He_2 molecules are excited to np Rydberg states using the frequency-doubled output of a pulse-amplified ring dye laser. Although the bandwidth of the laser system is too large to observe the reduction of the Doppler width resulting from deceleration, the deceleration greatly simplifies the spectral assignments because of its spin-rotational state selectivity. Our approach enabled us to determine the rotational structure of He_2 with an unprecedented accuracy of 18 MHz, to quantify the size of the relativistic and QED corrections by comparison with the results of Tung et al. and to precisely measure the rotational structure of the metastable state for comparison with the results of Focsa et al. Here, we present an extension of these measurements in which we have measured higher rotational intervals of He{_2}^+. In addition, we have replaced the pulsed UV laser by a cw UV laser and improved the resolution of the spectra by a factor of more than five. W.-C. Tung, M. Pavanello and L. Adamowicz, J. Chem. Phys. 136, 104309 (2012). P. Jansen, L. Semeria, L. Esteban Hofer, S. Scheidegger, J.A. Agner, H. Schmutz, and F. Merkt, Phys. Rev. Lett. 115, 133202 (2015). D. Sprecher, J. Liu, T. Krähenmann, M. Schäfer, and F. Merkt, J. Chem. Phys. 140, 064304 (2014). M

Improved sensitivity in patients with peripheral neuropathy: effects of monochromatic infrared photo energy.

Science.gov (United States)

DeLellis, Salvatore L; Carnegie, Dale H; Burke, Thomas J

2005-01-01

The medical records of 1,047 patients (mean age, 73 years) with established peripheral neuropathy were examined to determine whether treatment with monochromatic infrared photo energy was associated with increased foot sensitivity to the 5.07 Semmes-Weinstein monofilament. The peripheral neuropathy in 790 of these patients (75%) was due to diabetes mellitus. Before treatment with monochromatic infrared photo energy, of the ten tested sites (five on each foot), a mean +/- SD of 7.9 +/- 2.4 sites were insensitive to the 5.07 Semmes-Weinstein monofilament, and 1,033 patients exhibited loss of protective sensation. After treatment, the mean +/- SD number of insensate sites on both feet was 2.3 +/- 2.4, an improvement of 71%. Only 453 of 1,033 patients (43.9%) continued to have loss of protective sensation after treatment. Therefore, monochromatic infrared photo energy treatment seems to be associated with significant clinical improvement in foot sensation in patients, primarily Medicare aged, with peripheral neuropathy. Because insensitivity to the 5.07 Semmes-Weinstein monofilament has been reported to be a major risk factor for diabetic foot wounds, the use of monochromatic infrared photo energy may be associated with a reduced incidence of diabetic foot wounds and amputations.

The measurement and interpretation of Ne VII spectral line intensity ratios

International Nuclear Information System (INIS)

Lang, J.

1983-03-01

Results are presented for the measurement, using the branching ratios calibration method, of the spectral intensities of Ne VII lines emitted from a theta-pinch plasma whose electron temperature and density have been found by laser scattering and alternate techniques. (author)

Determination of the neutron detection efficiency of an NE213 scintillator for E{sub n}=2.5 to 16 MeV using the {sup 2}H(d,n){sup 3}He reaction

Energy Technology Data Exchange (ETDEWEB)

Al-Ohali, M.A.; Aksoy, A.; Coban, A. [King Fahd Univ. of Pet. and Miner., Dhahran (Saudi Arabia). Energy Res. Lab.; Hanly, J.M.; Felsher, P.D.; Howell, C.R.; Tornow, W.; Salinas, F.; Walter, R.L. [Duke University and Triangle Universities Nuclear Laboratories, Durham, NC 27708 (United States)

1997-09-11

The absolute efficiency of an NE213 liquid scintillator of 12.7 cm diameter and 5.08 cm thickness was measured in the neutron energy range 2.5-16 MeV using the {sup 2}H(d,n){sup 3}He reaction as a source of monoenergetic neutrons. The efficiencies were measured at the time-of-flight facility of Triangle Universities Nuclear Laboratory TUNL. The experimental data are compared to calculations from the Monte Carlo code NEFF of Physikalisch-Technische Bundesanstalt, Braunschweig, Germany PTB. (orig.). 7 refs.

Application Research of Quasi-monochromatic X-ray Machine Replacing 241Am Radioactive Source in Thickness Measurement

Directory of Open Access Journals (Sweden)

LIN Hui1;XIAO Xue-fu2;HOU Yue-xin3;ZHAO Jing1;JIAN Li-min1

2014-02-01

Full Text Available In the research of BS-03 thickness detector, a self-designed quasi-monochromatic (50-60 keV X-ray machine was studied as a substitution to Am-241 low energy photon source（1.11×109 Bq）The range of output current, the attenuation of X rays through the steel plate, the aluminum plate, and the organic glass plate and stability of quasi-monochromatic X-ray machine was tested. The result showed that quasi-monochromatic X-ray machine could be an applicable replacement of Am-241 radioactive source.

Plasma Profile Measurements for Laser Fusion Research with the Nike KrF Laser

Science.gov (United States)

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

2015-11-01

The grid image refractometer of the Nike laser facility (Nike-GIR) has demonstrated the capability of simultaneously measuring electron density (ne) and temperature (Te) profiles of coronal plasma. For laser plasma instability (LPI) research, the first Nike-GIR experiment successfully measured the plasma profiles in density regions up to ne ~ 4 ×1021 cm-3 (22% of the critical density for 248 nm light of Nike) using an ultraviolet probe laser (λp = 263 nm). The probe laser has been recently replaced with a shorter wavelength laser (λp = 213 nm, a 5th harmonic of the Nd:YAG laser) to diagnose a higher density region. The Nike-GIR system is being further extended to measure plasma profiles in the on-going experiment using 135°-separated Nike beam arrays for the cross-beam energy transfer (CBET) studies. We present an overview of the extended Nike-GIR arrangements and a new numerical algorithm to extract self-consistant plasma profiles with the measured quantities. Work supported by DoE/NNSA.

Exclusive measurement of the Ne = Pb → π ±, H, He at E/A = 400 and 800 MeV

International Nuclear Information System (INIS)

Poitou, J.; Babinet, R.; De Marco, N.

1987-06-01

This work is part of a systematic investigation of Ne-nucleus collisions undertaken with the 4 π detector Diogene. Only data obtained with Ne at 400 and 800 MeV/A on Pb nuclei are presented. Experimental data are also compared with the resuts of an intranuclear cascade calculation which takes, into account nuclear binding, Pauli blocking and isospin

Correlation corrections to the Hartree-Fock perturbation theory of atomic and molecular properties. Dipole polarizabilities of He, Be and Ne

International Nuclear Information System (INIS)

Sadlej, A.J.

1980-01-01

The problem of the most efficient perturbation calculation of the correlation contributions to atomic and molecular properties is discussed. The method which is based on the coupled Hartree-Fock (CHF) perturbation theory appears to be the most promising one. The CHF-based perturbation theory of correlation effects is applied to the calculation of the second-order correlation contributions to the electric dipole polarizabilities of He, Be and Ne. The numerical approach employed in this paper consists in computing first the electric-field-dependent SCF functions. Then, the field dependent second-order correlation energy is calculated. The electric dipole polarizabilities, accurate through the second-order in correlation, are obtained via the numerical differentiation of the field-dependent energies with respect to the external electric field strength. In order to avoid the use of very large basis sets the so-called electric-field-variant (EFV) orbitals are employed in the present study. The CHF results obtained in this paper are of the same accuracy as the best literature data. In addition of the second-order correlation correction the final values of the electric dipole polarizability differ from the accurate or experimental results by less than a few per cent. (author)

Electron collisions in noble gases

International Nuclear Information System (INIS)

Barros, H.G. P.L. de.

1973-12-01

Calculations for excitation cross section for some states of He and Ne by electron impact have been carried out. A parametrization of total and differential cross section in the Born-Ochkur approximation has been proposed. Using this parametrization and appropriated wave functions for the states involved in the collisions processes, the possibility of inversion of population in the He-Ne laser has been studied

Three-dimensional monochromatic x-ray computed tomography using synchrotron radiation

Science.gov (United States)

Saito, Tsuneo; Kudo, Hiroyuki; Takeda, Tohoru; Itai, Yuji; Tokumori, Kenji; Toyofuku, Fukai; Hyodo, Kazuyuki; Ando, Masami; Nishimura, Katsuyuki; Uyama, Chikao

1998-08-01

We describe a technique of 3D computed tomography (3D CT) using monochromatic x rays generated by synchrotron radiation, which performs a direct reconstruction of a 3D volume image of an object from its cone-beam projections. For the development, we propose a practical scanning orbit of the x-ray source to obtain complete 3D information on an object, and its corresponding 3D image reconstruction algorithm. The validity and usefulness of the proposed scanning orbit and reconstruction algorithm were confirmed by computer simulation studies. Based on these investigations, we have developed a prototype 3D monochromatic x-ray CT using synchrotron radiation, which provides exact 3D reconstruction and material-selective imaging by using the K-edge energy subtraction technique.

Monochromatic computed tomography of the human brain using synchrotron x rays: Technical feasibility

International Nuclear Information System (INIS)

Nachaliel, E.; Dilmanian, F.A.; Garrett, R.F.; Thomlinson, W.C.; Chapman, L.D.; Gmuer, N.F.; Lazarz, N.M.; Moulin, H.R.; Rivers, M.L.; Rarback, H.; Stefan, P.M.; Spanne, P.; Luke, P.N.; Pehl, R.; Thompson, A.C.; Miller, M.

1991-01-01

A monochromatic computed tomography (CT) scanner is being developed at the X17 superconducting wiggler beamline at the National Synchrotron Light Source (NSLS), Brookhaven National Laboratory, to image the human head and neck. The system configuration is one of a horizontal fan beam and an upright seated rotating subject. The purpose of the project are to demonstrate improvement in the image contrast and in the image quantitative accuracy that can be obtained in monochromatic CT and to apply the system to specific clinical research programs in neuroradiology. This paper describes the first phantom studies carried out with a prototype system, using the dual photon absorptiometry (DPA) method at energies of 20 and 39 Kev. The results show that improvements in image contrast and quantitative accuracy are possible with monochromatic DPA CT. Estimates of the clinical performance of the planned CT system are made on the basis of these initial results

Exchange currents in low-energy nucleon capture by 3He

International Nuclear Information System (INIS)

Wervelman, Rob.

1991-01-01

The studies described in this thesis concern absolute cross-section measurements of the radiative neutron capture reactions 3 He (n,γ) 4 He and 3 He(n,γγ) 4 He, and are complements with shell-model calculations on the radiative thermal neutron capture reaction by 3 He and on the weak 3 He(p,e + ν e ) 4 He reaction. The experiments have been performed at two neutron energies, with sub-thermal neutrons where s-wave capture is dominant, and with a quasi-monochromatic 24.5 keV neutron beam (p-wave capture). It has been found that the thermal neutron capture cross section of 3 He is 55±3 μb. Measured at 24.5 keV-neutron energy, the radiative capture cross section for p-wave neutrons turned out to be 9.1±0.8 μb. A measurement on the double-photon reaction 3 He(n th ,γγ) has yielded a cross-section value of 30±80 μb. In the theoretical part of the work a standard model of nuclear weak and electromagnetic interaction currents, consisting of a one-body impulse approximation and a two-body meson-exchange current part, has been applied to the process of nucleon capture by 3 He. Within the framework of a (0+2) (h/2π)ω shell-model calculation, using Sussex matrix elements for the 3 He and 4 He ground state wave functions, the empirical radiative cross sections for thermal neutrons of 3 He could be reproduced with satisfactory agreement. The total MEC correction to the radiative thermal neutron capture cross section is rather small because large cancellations occur between the various contributions. In the 3 He(p,e + ν e ) 4 He reaction meson-exchange contributions enlarge the astrophysical S-factor by more than a factor two. The matrix element ratio of the weak 3 He+p and the electromagnetic 3 He+n reaction is calculated to be (4.3±0.6)g A C 0 . This ratio has been found to be fairly insensitive to the percentage D-state admixtures in the 3 He and 4 He ground state wave functions. (author). 129 refs.; 24 figs.; 5 tabs

The formation and reactivity of the μ+ molecular ion NeMu+

International Nuclear Information System (INIS)

Fleming, D.G.; Mikula, R.J.; Senba, M.; Garner, D.M.; Arseneau, D.J.

1983-06-01

Evidence for the formation and reactivity of the positive muon molecular ion NeMu + at room temperature in a low pressure Ne moderator to which trace amounts of Xe, CH 4 , NH 3 or He have been added, is reported. A two component relaxation of the diamagnetic muon spin rotation (μSR) signal is seen upon the addition of trace amounts of Xe to Ne; a fast relaxing component with bimolecular rate constant (3.6+-0.6) x 10 -10 cc atom -1 s -1 is thought to be due to thermal muonium formation in a charge exchange process while the other slow relaxing component is attributed to a muon transfer reaction, as in proton transfer studies. With CH 4 or NH 3 added to Ne there is, at most, only a very slow relaxation seen, even though thermal muonium formation is expected, in analogy with Xe. These latter results may be due to very fast, possibly tunneling-assisted, muon transfer reactions, the first time that such processes have been at all characterized

Single slit interference made easy with a strand of hair and a laser

Science.gov (United States)

Messer, Rebecca

2018-01-01

Students can easily measure the width of a strand of their own hair with a monochromatic light source such as a laser. This inexpensive activity engages students in an application of single slit diffraction using Babinet's principle.

Curved crystal x-ray optics for monochromatic imaging with a clinical source.

Science.gov (United States)

Bingölbali, Ayhan; MacDonald, C A

2009-04-01

Monochromatic x-ray imaging has been shown to increase contrast and reduce dose relative to conventional broadband imaging. However, clinical sources with very narrow energy bandwidth tend to have limited intensity and field of view. In this study, focused fan beam monochromatic radiation was obtained using doubly curved monochromator crystals. While these optics have been in use for microanalysis at synchrotron facilities for some time, this work is the first investigation of the potential application of curved crystal optics to clinical sources for medical imaging. The optics could be used with a variety of clinical sources for monochromatic slot scan imaging. The intensity was assessed and the resolution of the focused beam was measured using a knife-edge technique. A simulation model was developed and comparisons to the measured resolution were performed to verify the accuracy of the simulation to predict resolution for different conventional sources. A simple geometrical calculation was also developed. The measured, simulated, and calculated resolutions agreed well. Adequate resolution and intensity for mammography were predicted for appropriate source/optic combinations.

Theoretical designs of 19.6 nm Ne-like Ge XRL source

International Nuclear Information System (INIS)

Zhang Guoping; Zhang Tanxin; Zheng Wudi

2004-01-01

19.6 nm Ne-like Ge X-ray laser (XRL) can be used as a source to diagnose Rayleigh-Taylor instability in laser induced plasma. In this paper, systemic optimum designs and theoretical analysis to Ne-like Ge XRL driven by pre-main short pulses were conducted by a series of codes, which had been tested by experiments. Simulation results show that, adopting driven conditions of 2%-3% pre-pulse, 6-8 ns pre-main pulse interval and 40 TW/cm 2 power intensity, a gain area of 19.6 nm laser line beyond 60 μm and gain duration of 90 ps can be obtained. Furthermore, with 16 mm plane target, the gain gets to 11.8/cm, and if 6 mrad/cm curved target is adopted, it reaches to 13.3/cm, and small signal gain-length product of single target is about 21.3, which means that saturated gain can be realized by a single target. With double targets opposite coupling, gain-length product can reach 38.4, deep saturation can be gotten, and XRL source required by demonstration of application is out of question

Photodynamic therapy for hair removal

Directory of Open Access Journals (Sweden)

Mohamed H. M. Ali

2013-05-01

Full Text Available Background: Unwanted hair is one of the most common medical problems affecting women of reproductive age inducing a lot of psychological stress and threatening their femininity and self-esteem. Old methods of removing unwanted hair include shaving, waxing, chemical depilation, and electrolysis, all of which have temporary results. However laser-assisted hair removal is the most efficient method of long-term hair removal currently available. It is desirable to develop a reduced cost photodynamic therapy (PDT system whose properties should include high efficiency and low side-effects. Method: Mice skin tissues were used in this study and divided into six groups such as controls, free methylene blue (MB incubation, liposome methylene blue (MB incubation, laser without methylene blue (MB, free methylene blue (MB for 3 and 4 hrs and laser, liposome methylene blue (MB for 3 hrs and laser. Methylene blue (MBwas applied to wax epilated areas. The areas were irradiated with CW He-Ne laser system that emits orange-red light with wavelength 632.8 nm and 10 mW at energy density of 5 J/ cm2 for 10 minutes. The UV-visible absorption spectrum was collected by Cary spectrophotometer. Results: Methylene blue (MB is selectively absorbed by actively growing hair follicles due to its cationic property. Methylene blue (MBuntreated sections showed that hair follicle and sebaceous gland are intact and there is no change due to the laser exposure. Free methylene blue (MB sections incubated for 3 hrs showed that He:Ne laser induced destruction in hair follicles, leaving an intact epidermis. Treated section with free methylene blue (MB for 4 hrs showed degeneration and necrosis in hair follicle, leaving an intact epidermis. Liposomal methylene blue (MB sections incubated for 3 hrs showed He:Ne laser induced destruction in hair follicles with intradermal leucocytic infiltration. Conclusions: Low power CW He:Ne laser and methylene blue (MB offered a successful PDT system

Associative ionization of neon and helium atoms by collisions of excited helium (31p) atoms of thermal energies

International Nuclear Information System (INIS)

Runge, Serge.

1980-12-01

The relative cross-sections of ionizing collisions between He + He and He + Ne atoms, have been studied, the helium being excited in a state (3 1 p) by a laser beam. The results obtained made it possible (a) to reveal in a direct manner the production of molecular ions He 2 + and He Ne + and (b) to determine the relative change in the associative ionizing cross-section in the area (0.035 - 0.17 eV) in the He (3 1 P) + Ne collision, despite the very short life of the He (3 1 P) excited state (1.7 ns). The production of He 2 + ions from an He (3 1 P) + He collision sets an upper limit to the appearance potential of these ions. The experimental study of the associative ionization in the He (3 1 P) + Ne system made it possible to extend the utilization of the GAMMA(R) self ionization model, already tested for the metastable states, to the radiative states. The GAMMA(R) model seems well suited for the description of collisions of the A excited + B type, where the excitation energy of A is greater than the ionization potential of B [fr

Laser stimulation can activate autophagy in HeLa cells

International Nuclear Information System (INIS)

Wang, Yisen; Hu, Minglie; Wang, Chingyue; Lan, Bei; Cao, Youjia; He, Hao

2014-01-01

For decades, lasers have been a daily tool in most biological research for fluorescent excitation by confocal or multiphoton microscopy. More than 20 years ago, cell photodamage caused by intense laser stimulation was noticed by generating reactive oxygen species, which was then thought as the main damage effect by photons. In this study, we show that laser stimulation can induce autophagy, an important cell lysosomal pathway responding to immune stimulation and starvation, without any biochemical treatment. Two different types of laser stimulations are found to be capable of activating autophagy: continuous scanning by continuous-wave visible lasers and a short-time flash of femtosecond laser irradiation. The autophagy generation is independent from wavelength, power, and scanning duration of the visible lasers. In contrast, the power of femtosecond laser is very critical to autophagy because the multiphoton excited Ca 2+ dominates autophagy signaling. In general, we show here the different mechanisms of autophagy generation by such laser stimulation, which correspond to confocal microscopy and cell surgery, respectively. Those results can help further understanding of photodamage and autophagy signaling.

Laser stimulation can activate autophagy in HeLa cells

Energy Technology Data Exchange (ETDEWEB)

Wang, Yisen; Hu, Minglie; Wang, Chingyue [Ultrafast Laser Laboratory, Key Laboratory of Optoelectronic Information Technology (Ministry of Education), College of Precision Instrument and Optoelectronics Engineering, Tianjin University, Tianjin (China); Lan, Bei; Cao, Youjia [Key Laboratory of Microbial Functional Genomics of Ministry of Education, College of Life Sciences, Nankai University, Tianjin (China); He, Hao, E-mail: haohe@tju.edu.cn [Ultrafast Laser Laboratory, Key Laboratory of Optoelectronic Information Technology (Ministry of Education), College of Precision Instrument and Optoelectronics Engineering, Tianjin University, Tianjin (China); Med-X Research Institute, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai (China)

2014-10-27

For decades, lasers have been a daily tool in most biological research for fluorescent excitation by confocal or multiphoton microscopy. More than 20 years ago, cell photodamage caused by intense laser stimulation was noticed by generating reactive oxygen species, which was then thought as the main damage effect by photons. In this study, we show that laser stimulation can induce autophagy, an important cell lysosomal pathway responding to immune stimulation and starvation, without any biochemical treatment. Two different types of laser stimulations are found to be capable of activating autophagy: continuous scanning by continuous-wave visible lasers and a short-time flash of femtosecond laser irradiation. The autophagy generation is independent from wavelength, power, and scanning duration of the visible lasers. In contrast, the power of femtosecond laser is very critical to autophagy because the multiphoton excited Ca{sup 2+} dominates autophagy signaling. In general, we show here the different mechanisms of autophagy generation by such laser stimulation, which correspond to confocal microscopy and cell surgery, respectively. Those results can help further understanding of photodamage and autophagy signaling.

The possibilities of laser scattering diagnostics in plasmas

International Nuclear Information System (INIS)

Doebele, H.F.

1974-01-01

The laser has opened many new possibilities for plasma diagnostics. Intensive monochromatic light sources with higher precision and better time resolution have helped to improve such well-known techniques as interferometry and Schlieren method. At the same time, the range of applicability was extended into the infrared range. Due to the wave length dependence of the plasma diffraction index, the effects increase approximately lambda in interferometry and approximately lambda 2 in the Schlieren methods. The laser also helped to develop entirely new methods such as utilization of the Faraday effect in the electrons of a plasma in a magnetic field which allows the calculation of the product nsub(e) x B from the rotation of the polarization plane of monochromatic light with linear polarization. Here, too, the effect increases approximately lambda 2 , and measurements have been carried out up to FIR (HCN,337 μ). The best diagnostic possibilities are offered by the Thomson scattering diagnostics. Electron and ion temperatures, electron densities, drift velocities, magnetic fields, wave propagation and dissipation can be measured by this method. (orig./AK) [de

Double capture in the O/sup 8+/ + He collision investigated by electron spectroscopy (80 keV, 10 deg)

Energy Technology Data Exchange (ETDEWEB)

Moretto-Capelle, P.; Benoit-Cattin, P.; Bordenave-Montesquieu, A.; Boudjema, M.; Gleizes, A.; Oza, D.H.; Dousson, S.; Hitz, D.

1989-01-28

Double capture into (3,n) autoionising states of O/sup 6+/ is observed in the O/sup 8+/ + He collision system by electron spectroscopy at 80 keV, 10/sup 0/. A comparison of the experimental results with theoretical positions and lifetimes allows the (3,3) states as well as three groups of (3,4) states to be identified. The present experimental findings are compared with earlier data for the N/sup 7+/ + He and Ne/sup 8+/(1s/sup 2/) + He systems. The influence of the core of the multicharged ion is studied by examining the O/sup 8+/ and Ne/sup 8+/(1s/sup 2/) results. The total double capture cross section is found to be large and it is compared with available experimental and theoretical data.

Differential cross sections for non-sequential double ionization of He by 52 eV photons from the Free Electron Laser in Hamburg, FLASH

International Nuclear Information System (INIS)

Kurka, M; Rudenko, A; Jiang, Y H; Kuehnel, K U; Foucar, L; Feist, J; Pazourek, R; Nagele, S; Horner, D A; Rescigno, T N; McCurdy, C W; Schoeffler, M; Belkacem, A; Schulz, M; Herrwerth, O; Lezius, M; Kling, M F; Duesterer, S; Treusch, R; Schneider, B I

2010-01-01

Two-photon double ionization of He is studied at the Free Electron Laser in Hamburg (FLASH) by inspecting He 2+ momentum (P-vector(He 2+ )) distributions at 52 eV photon energy. We demonstrate that recoil ion momentum distributions can be used to infer information about highly correlated electron dynamics and find the first experimental evidence for 'virtual sequential ionization'. The experimental data are compared with the results of two calculations, both solving the time-dependent Schroedinger equation. We find good overall agreement between experiment and theory, with significant differences for cuts along the polarization direction that cannot be explained by the experimental resolution alone.

Experimental investigation of dissociation pathways of cooled HeH+ following valence electron excitation at 32 nm by intense free-electron-laser radiation

International Nuclear Information System (INIS)

Pedersen, H. B.; Lammich, L.; Domesle, C.; Jordon-Thaden, B.; Ullrich, J.; Wolf, A.; Heber, O.; Treusch, R.; Guerassimova, N.

2010-01-01

The dissociation pathways of HeH + have been investigated below the first ionization continuum by photoabsorption at 32 nm, using fragment momentum imaging in a crossed-beams experiment at the free-electron laser in Hamburg (FLASH). Investigations were done both for ions with several vibrational levels excited in the ion source and for ions vibrationally cooled in an electrostatic ion trap prior to the irradiation. The product channels He + (1s)+H(nl) and He(1snl)+H + were separated and the He(1snl)+H + channel was particularly studied by coincidence detection of the He and H + fragments on two separate fragment detectors. At 32 nm excitation, the branching ratio between the product channels was found to be σ He + +H /σ He+H + =0.96±0.11 for vibrationally hot and 1.70±0.48 for vibrationally cold ions. The spectra of kinetic energy releases for both channels revealed that photodissociation at 32 nm leads to high Rydberg states (n > or approx. 3-4) of the emerging atomic fragments irrespective of the initial vibrational excitation of HeH + . The fragment angular distributions showed that dissociation into the He+H + channel mostly (∼70%) proceeds through 1 Π states, while for the He + +H channel 1 Σ and 1 Π states are of about equal importance.

Absolute distance measurement with extension of nonambiguity range using the frequency comb of a femtosecond laser

Science.gov (United States)

Jang, Yoon-Soo; Lee, Keunwoo; Han, Seongheum; Lee, Joohyung; Kim, Young-Jin; Kim, Seung-Woo

2014-12-01

We revisit the method of synthetic wavelength interferometry (SWI) for absolute measurement of long distances using the radio-frequency harmonics of the pulse repetition rate of a mode-locked femtosecond laser. Our intention here is to extend the nonambiguity range (NAR) of the SWI method using a coarse virtual wavelength synthesized by shifting the pulse repetition rate. The proposed concept of NAR extension is experimentally verified by measuring a ˜13-m distance with repeatability of 9.5 μm (root-mean-square). The measurement precision is estimated to be 31.2 μm in comparison with an incremental He-Ne laser interferometer. This extended SWI method is found to be well suited for long-distance measurements demanded in the fields of large-scale precision engineering, geodetic survey, and future space missions.

A rate-equation model for polarized laser-induced fluorescence to measure electric field in glow discharge He plasmas

International Nuclear Information System (INIS)

Takiyama, K.; Watanabe, M.; Oda, T.

1998-01-01

Possibility of applying polarized laser-induced fluorescence (LIF) spectroscopy for measuring the electric field in a plasma with a large collisional depolarization has been investigated. A rate equation model including the depolarization process was employed to analyze the time evolution of LIF polarization components. The polarized LIF pulse shapes observed in the sheath of a He glow discharge plasma were successfully reproduced, and the electric field distribution was obtained with high accuracy. (author)

U,Th-21Ne dating and its applications

International Nuclear Information System (INIS)

Basu, Sudeshna; Murty, S.V.S.; Anil Kumar

2003-01-01

The potential of radiogenic and fissiogenic noble gas isotopes as dating tools has been well exploited. U, Th- 4 He , K- 40 Ar and U- fission Xe pairs as well as their variants like 39 Ar- 40 Ar and induced fission Xe- spontaneous fission Xe pairs have been extensively used as geochronological tools. A new dating method that utilizes the nucleogenic isotope 21 Ne and demonstrate its application for an apatite separate from a carbonatite is proposed

Characterization of Electron Temperature and Density Profiles of Plasmas Produced by Nike KrF Laser for Laser Plasma Instability (LPI) Research

Science.gov (United States)

Oh, Jaechul; Weaver, J. L.; Phillips, L.; Obenschain, S. P.; Schmitt, A. J.; Kehne, D. M.; Chan, L.-Y.; Serlin, V.

2011-10-01

Previous experiments with Nike KrF laser (λ = 248 nm , Δν ~ 1 THz) observed LPI signatures near quarter critical density (nc / 4) in CH plasmas, however, detailed measurement of the temperature (Te) and density (ne) profiles was missing. The current Nike LPI campaign will perform experimental determination of the plasma profiles. A side-on grid imaging refractometer (GIR) is the main diagnostic to resolve Te and ne in space taking 2D snapshots of probe laser (λ = 266 nm , Δt = 8 psec) beamlets (50 μm spacing) refracted by the plasma at laser peak time. Ray tracing of the beamlets through hydrodynamically simulated (FASTRAD3D) plasma profiles estimates the refractometer may access densities up to ~ 0 . 2nc . With the measured Te and ne profiles in the plasma corona, we will discuss analysis of light data radiated from the plasmas in spectral ranges relevant to two plasmon decay and convective Raman instabilities. Validity of the (Te ,ne) data will also be discussed for the thermal transport study. Work supported by DoE/NNSA and ONR and performed at NRL.

Nonlinear optical measurements of conducting copolymers of aniline under CW laser excitation

Science.gov (United States)

Pramodini, S.; Poornesh, P.

2015-08-01

Synthesis and measurements of third-order optical nonlinearity and optical limiting of conducting copolymers of aniline are presented. Single beam z-scan technique was employed for the nonlinear optical studies. Continuous wave He-Ne laser operating at 633 nm was used as the source of excitation. Copolymer samples exhibited reverse saturable absorption (RSA) process. The nonlinear refraction studies depict that the copolymers exhibit self-defocusing property. The estimated values of βeff, n2 and χ(3) were found to be of the order of 10-2 cm/W, 10-5 esu and 10-7 esu respectively. Self-diffraction rings were observed due to refractive index change when exposed to the laser beam. A good optical limiting and clamping of power of ∼0.9 mW and ∼0.05 mW was observed. Therefore, copolymers of aniline emerge as a potential candidate for photonic device applications.

Improved photochemotherapy of malignant cells with daunomycin and the KTP laser.

Science.gov (United States)

Paiva, M B; Saxton, R E; Graeber, I P; Jongewaard, N; Eshraghi, A A; Suh, M J; Paek, W H; Castro, D J

1998-01-01

Laser photochemotherapy of malignancies may become an effective palliative treatment for advanced had and neck cancer using light-sensitive, chemotherapeutic drugs activated in tumors via interstitial laser fiberoptics. Previously, it was reported that cultured human P3 squamous cells incubated 2 hours with daunomycin (Dn) exhibited tenfold enhanced cytotoxicity after exposure to argon laser light at 514 nm. This short-term uptake leads to drug localization in cytoplasmic and membrane sites prior to nuclear accumulation and daunomycin topoisomerase inhibition. In the current study phototoxicity of Dn-sensitized human cancer cells was tested using broad-spectrum white light compared to monochromatic green-wavelength light. Drug uptake and laser energy levels were optimized for maximum synergy. To test light-enhanced chemotherapy in vitro, the kinetics of cell uptake and toxicity of daunomycin was measured at 1, 2, and 5 microg/ml in three human tumor cell lines: P3 squamous-cell carcinoma, M26 melanoma, and TE671 fibrosarcoma. After 2 hr Dn uptake, all cell lines were tested for phototherapy response by exposure to 300- to 900-nm visible light from a xenon lamp or monochromatic 532-nm green light from a KTP laser. When the KTP laser output was varied from 0 to 120 Joules in Dn-sensitized tumor cells, a linear phototherapy response was seen with energy as low as 12 J inducing drug phototoxicity. These results provide evidence that daunomycin cytotoxicity is enhanced when exposed to 532-nm laser illumination in the three tumor types tested and confirm that the response is related to both energy level and drug dose.

Direct and inverse Staebler-Wronski effects observed in carbon-doped hydrogenated amorphous silicon photo-detectors

International Nuclear Information System (INIS)

Arce, P.; Barcala, J.M.; Calvo, E.; Ferrando, A.; Josa, M.I.; Molinero, A.; Navarrete, J.; Oller, J.C.; Yuste, C.; Brochero, J.; Calderon, A.; Fernandez, M.G.; Gomez, G.; Gonzalez-Sanchez, F.J.; Martinez-Rivero, C.; Matorras, F.; Rodrigo, T.; Ruiz-Arbol, P.; Scodellaro, L.; Sobron, M.

2011-01-01

The photo-response behaviour of Amorphous Silicon Position Detectors (ASPDs) under prolonged illumination with a 681 nm diode-laser and a 633 nm He-Ne laser is presented. Both direct and inverse Staebler-Wronski effects are observed.

Photofission of NAT Pt by monochromatic and polarized photons in the quasi-deuteron region

International Nuclear Information System (INIS)

Paiva, Eduardo de.

1992-01-01

The measurement of the Nat Pt photofission yield at 69 MeV of effective average energy of the incident photon is made using a polarized and monochromatic photon beam from the LADON system of the National Laboratory of Frascati, Italy, produced by inverse Compton scattering of laser light by high energy electrons of the ADONE Accelerator and using as fission track solid detector the Makrofol, being the developing made by usual procedure. The experimental value of the nuclear fissionability is compared to a theoretical value obtained following a model at two stages: in the first, the photon energy is absorbed by a neutron-proton pair inducing to the nucleus excitation, and in the second the nucleus de-excites due to the competition between nucleon evaporation and fission. The effect of fast nucleon emission during the first stage and the successive evaporation of neutrons in the second stage are considered. 40 refs, 12 figs, 9 tabs

Vegetation Detection in Stress of Moisture Shortage Based on Laser Speckle Recognition

Science.gov (United States)

Ishizawa, Hiroaki; Matsuo, Tsukasa; Miki, Takashi

This paper describes a new measuring method of plant vigor by using Laser speckle pattern. Furthermore, this proposes a practical application of this presented measurement system. The measuring instrument is consisted by a He-Ne Laser as the light source, and a set of optics, such as reflectors, a beam expander. The speckle pattern could be measured by a CCD camera through lenses. A Pothos (Epiremnum aureum) and Japanese morning glory (Ipomoea nil) were used as the sample plant. Their intact leaves were measured the speckle pattern images. Visible but small vigor veins could be clearly observed in the images obtained by the speckle patterns. On the other hand, withered ones have shown different images. The relationship has been obtained between the feature of the images and the chlorophyll degradation. It would be expected that the symptom of plant against some stress could be detected by measuring the Laser speckle pattern. It could be used as the sensor of the field server system at every field monitoring site.

Evidence for leading mesons in anti p4He reactions at 0.6 GeV/c incident momentum

International Nuclear Information System (INIS)

Breivik, F.O.; Haatuft, A.; Halsteinslid, A.

1990-05-01

In a previous report, evidence has been shown for leading mesons in anti p Ne - reactions at 0.6 Gev/c incident momentum. In this report evidence is shown for leading mesons in anti p 4 He reactions at the same incident momentum, based on data from the same detector. In anti p Ne - reactions, only kaons are observed as leading mesons in K o s-events, and only pions are observed as leading mesons in Λ o -events. In anti p He - reactions this is not longer true, since also pions behave as leading mesons in K o s-events. 5 refs., 9 figs

Efficiency limits of laser power converters for optical power transfer applications

International Nuclear Information System (INIS)

Mukherjee, J; Jarvis, S; Sweeney, S J; Perren, M

2013-01-01

We have developed III–V-based high-efficiency laser power converters (LPCs), optimized specifically for converting monochromatic laser radiation at the eye-safe wavelength of 1.55 µm into electrical power. The applications of these photovoltaic cells include high-efficiency space-based and terrestrial laser power transfer and subsequent conversion to electrical power. In addition, these cells also find use in fibre-optic power delivery, remote powering of subcutaneous equipment and several other optical power delivery applications. The LPC design is based on lattice-matched InGaAsP/InP and incorporates elements for photon-recycling and contact design for efficient carrier extraction. Here we compare results from electro-optical design simulations with experimental results from prototype devices studied both in the lab and in field tests. We analyse wavelength and temperature dependence of the LPC characteristics. An experimental conversion efficiency of 44.6% [±1%] is obtained from the prototype devices under monochromatic illumination at 1.55 µm (illumination power density of 1 kW m −2 ) at room temperature. Further design optimization of our LPC is expected to scale the efficiency beyond 50% at 1 kW m −2 . (paper)

Efficiency limits of laser power converters for optical power transfer applications

Science.gov (United States)

Mukherjee, J.; Jarvis, S.; Perren, M.; Sweeney, S. J.

2013-07-01

We have developed III-V-based high-efficiency laser power converters (LPCs), optimized specifically for converting monochromatic laser radiation at the eye-safe wavelength of 1.55 µm into electrical power. The applications of these photovoltaic cells include high-efficiency space-based and terrestrial laser power transfer and subsequent conversion to electrical power. In addition, these cells also find use in fibre-optic power delivery, remote powering of subcutaneous equipment and several other optical power delivery applications. The LPC design is based on lattice-matched InGaAsP/InP and incorporates elements for photon-recycling and contact design for efficient carrier extraction. Here we compare results from electro-optical design simulations with experimental results from prototype devices studied both in the lab and in field tests. We analyse wavelength and temperature dependence of the LPC characteristics. An experimental conversion efficiency of 44.6% [±1%] is obtained from the prototype devices under monochromatic illumination at 1.55 µm (illumination power density of 1 kW m-2) at room temperature. Further design optimization of our LPC is expected to scale the efficiency beyond 50% at 1 kW m-2.

Spectroscopy of lithium atoms sublimated from isolation matrix of solid Ne.

Science.gov (United States)

Sacramento, R L; Scudeller, L A; Lambo, R; Crivelli, P; Cesar, C L

2011-10-07

We have studied, via laser absorption spectroscopy, the velocity distribution of (7)Li atoms released from a solid neon matrix at cryogenic temperatures. The Li atoms are implanted into the Ne matrix by laser ablation of a solid Li precursor. A heat pulse is then applied to the sapphire substrate sublimating the matrix together with the isolated atoms at around 12 K. We find interesting differences in the velocity distribution of the released Li atoms from the model developed for our previous experiment with Cr [R. Lambo, C. C. Rodegheri, D. M. Silveira, and C. L. Cesar, Phys. Rev. A 76, 061401(R) (2007)]. This may be due to the sublimation regime, which is at much lower flux for the Li experiment than for the Cr experiment, as well as to the different collisional cross sections between those species to the Ne gas. We find a drift velocity compatible with Li being thermally sublimated at 11-13 K, while the velocity dispersion around this drift velocity is low, around 5-7 K. With a slow sublimation of the matrix we can determine the penetration depth of the laser ablated Li atoms into the Ne matrix, an important information that is not usually available in most matrix isolation spectroscopy setups. The present results with Li, together with the previous results with Cr suggest this to be a general technique for obtaining cryogenic atoms, for spectroscopic studies, as well as for trap loading. The release of the isolated atoms is also a useful tool to study and confirm details of the matrix isolated atoms which are masked or poorly understood in the solid. © 2011 American Institute of Physics

Lasers in ophthalmology: achievements and new directions

Science.gov (United States)

Carstocea, Benone D.; Apostol, Silvia; Gafencu, Otilia L.

1995-03-01

The main characteristics of the laser radiations are: directivity, monochromaticity and spatially and temporally coherence. Using the aggregation state as a criterion for classification, we describe solid, liquid and gaseous active media. Concerning the methods used to realize the population inversion, we also describe: optically, electrically and high energy particles pumped lasers. Depending on the laser media and the mode of excitation, a laser may operate in multiple ways: the continuous-wave operation, the long-pulsed operation, the Q-switched mode of operation and the mode-locked operation. The interaction of laser radiations with the living matter is based upon four main effects: the thermal, mechanical, electrical and biological effect. The main field of therapeutical use of lasers are: the management of lid tumors and intraocular tumors, dacryocystorhinostomy, the treatment of diabetic retinopathy, thromboembolic retinal syndromes, inflammatory choriretinal disease, chorioroetinal degenerations, retinal angimatosis, retinal breaks and retinal detachment, corneal diseases, glaucoma, lens diseases. Laser has also nontherapeutical applications in diagnosis and prognosis of ophthalmologic diseases.

Selecting optimal monochromatic level with spectral CT imaging for improving imaging quality in hepatic venography

International Nuclear Information System (INIS)

Sun Jun; Luo Xianfu; Wang Shou'an; Wang Jun; Sun Jiquan; Wang Zhijun; Wu Jingtao

2013-01-01

Objective: To investigate the effect of spectral CT monochromatic images for improving imaging quality in hepatic venography. Methods: Thirty patients underwent spectral CT examination on a GE Discovery CT 750 HD scanner. During portal phase, 1.25 mm slice thickness polychromatic images and optimal monochromatic images were obtained, and volume rendering and maximum intensity projection were created to show the hepatic veins respectively. The overall imaging quality was evaluated on a five-point scale by two radiologists. Inter-observer agreement in subjective image quality grading was assessed by Kappa statistics. Paired-sample t test were used to compare hepatic vein attenuation, hepatic parenchyma attenuation, CT value difference between the hepatic vein and the liver parenchyma, image noise, vein-to-liver contrast-to-noise ratio (CNR), the image quality score of hepatic venography between the two image data sets. Results: The monochromatic images at 50 keV were found to demonstrate the best CNR for hepatic vein.The hepatic vein attenuation [(329 ± 47) HU], hepatic parenchyma attenuation [(178 ± 33) HU], CT value difference between the hepatic vein and the liver parenchyma [(151 ± 33) HU], image noise (17.33 ± 4.18), CNR (9.13 ± 2.65), the image quality score (4.2 ± 0.6) of optimal monochromatic images were significantly higher than those of polychromatic images [(149 ± 18) HU], [(107 ± 14) HU], [(43 ±11) HU], 12.55 ± 3.02, 3.53 ± 1.03, 3.1 ± 0.8 (t values were 24.79, 13.95, 18.85, 9.07, 13.25 and 12.04, respectively, P < 0.01). In the comparison of image quality, Kappa value was 0.81 with optimal monochromatic images and 0.69 with polychromatic images. Conclusion: Monochromatic images of spectral CT could improve CNR for displaying hepatic vein and improve the image quality compared to the conventional polychromatic images. (authors)

Towards a Monochromatization Scheme for Direct Higgs Production at FCC-ee

CERN Document Server

Valdivia Garcia, Marco Alan; Zimmermann, Frank

2016-01-01

Direct Higgs production in e+e− collisions at the FCC is of interest if the centre-of-mass energy spread can be reduced by at least an order of magnitude. A monochromatization scheme, to accomplish this, can be realized with horizontal dispersion of opposite sign for the two colliding beams at the interaction point (IP). We recall historical approaches to monochromatization, then derive a set of IP parameters which would provide the required performance in FCC e+e− collisions at 62.5 GeV beam energy, compare these with the baseline optics parameters at neighbouring energies (45.6 and 80 GeV), comment on the effect of beamstrahlung, and indicate the modifications of the FCC-ee final-focus optics needed to obtain the required parameters.

The use of laser beams for plasma diagnostics

International Nuclear Information System (INIS)

Gex, J.P.; Jolas, A.; Launspach, J.; Schirmann, D.

1975-01-01

The optical properties of lasers allow them to be a promising source for plasma diagnosis. The Q-switched lasers provide the opportunity to make observations in a very short time interval down to a few picoseconds. The laser space and time coherence properties allow interferometric measurements of plasma electron densities. Thus in the experiments of laser-matter interactions, the radiation obtained by frequency conversion of the Nd: glass laser emission is used for density measurements (up to 10 20 cm -3 ) in small scale plasmas (approximately equal to 1mm). Owing to the monochromaticity and high intensity of the Q-switched laser radiation, density fluctuations and microscopic instabilities of the plasma can be studied by Thompson scattering measurements. Finally, some statistically isotropic media become birefringent under the action of the strong electrical field of the laser beam radiation. This effect can be used for laser pulse duration measurements in a range not exceeding a few picoseconds [fr

Ühe näoga Janus / Mart Raukas

Index Scriptorium Estoniae

Raukas, Mart

2008-01-01

Tänapäeva lääne poliitikud, lähtudes oma avaldustes aina enam tüüpilistest moraalihinnangutest, unustavad, et ükski moraalne reageering ei ole pelgalt reageering faktidele, vaid selle teeb moraalselt relevantseks olukorrale langetatud hinnang ja sellest lähtuv reageering. Õigluseta ühiskond ei erine suurest röövlijõugust ning see, kes mõistab hukka ühe suurriigi tegevuse, olgu kriitiline ka teise suurjõu osas

He, U, and Th Depth Profiling of Apatite and Zircon Using Laser Ablation Noble Gas Mass Spectrometry and SIMS

Science.gov (United States)

Monteleone, B. D.; van Soest, M. C.; Hodges, K. V.; Hervig, R.; Boyce, J. W.

2008-12-01

Conventional (U-Th)/He thermochronology utilizes single or multiple grain analyses of U- and Th-bearing minerals such as apatite and zircon and does not allow for assessment of spatial variation in concentration of He, U, or Th within individual crystals. As such, age calculation and interpretation require assumptions regarding 4He loss through alpha ejection, diffusive redistribution of 4He, and U and Th distribution as an initial condition for these processes. Although models have been developed to predict 4He diffusion parameters, correct for the effect of alpha ejection on calculated cooling ages, and account for the effect of U and Th zonation within apatite and zircon, measurements of 4He, U, and Th distribution have not been combined within a single crystal. We apply ArF excimer laser ablation, combined with noble gas mass spectrometry, to obtain depth profiles within apatite and zircon crystals in order to assess variations in 4He concentration with depth. Our initial results from pre-cut, pre-heated slabs of Durango apatite, each subjected to different T-t schedules, suggest a general agreement of 4He profiles with those predicted by theoretical diffusion models (Farley, 2000). Depth profiles through unpolished grains give reproducible alpha ejection profiles in Durango apatite that deviate from alpha ejection profiles predicted for ideal, homogenous crystals. SIMS depth profiling utilizes an O2 primary beam capable of sputtering tens of microns and measuring sub-micron resolution variation in [U], [Th], and [Sm]. Preliminary results suggest that sufficient [U] and [Th] zonation is present in Durango apatite to influence the form of the 4He alpha ejection profile. Future work will assess the influence of measured [U] and [Th] zonation on previously measured 4He depth profiles. Farley, K.A., 2000. Helium diffusion from apatite; general behavior as illustrated by Durango fluorapatite. J. Geophys. Res., B Solid Earth Planets 105 (2), 2903-2914.

Laser polarimetry

International Nuclear Information System (INIS)

Goldstein, D.H.

1989-01-01

Polarimetry, or transmission ellipsometry, is an important experimental technique for the determination of polarization properties of bulk materials. In this technique, source radiation of known polarization is passed through bulk samples to determine, for example, natural or induced birefringence and dichroism. The laser is a particularly appropriate source for this technique because of its monochromaticity, collimation, and radiant intensity. Lasers of many different wavelengths in different spectral regions are now available. Laser polarimetry can be done in any of these wavelength regions where polarizing elements are available. In this paper, polarimetry is reviewed with respect to applications, sources used, and polarization state generator and analyzer configurations. Scattering ellipsometry is also discussed insofar as the forward scattering measurement is related to polarimetry. The authors then describe an infrared laser polarimeter which we have designed and constructed. This instrument can operate over large wavelength regions with only a change in source. Polarization elements of the polarimeter are in a dual rotating retarder configuration. Computer controlled rotary stages and computer monitored detectors automate the data collection. The Mueller formulation is used to process the polarization information. Issues and recent progress with this instrument are discussed

Laser beams in high energy physics

International Nuclear Information System (INIS)

Milburn, R.H.

1976-01-01

Back-scattered ruby laser light from energetic electrons has facilitated a family of bubble chamber experiments in the interactions of highly polarized and quasi-monochromatic photons up to 10 GeV with 4π acceptance at the 100 to 200 event/μb level. Further studies of this sort demand the use of high-repetition-rate track chambers. To exploit the polarization and energetic purity intrinsic to the back-scattered beam one must achieve nearly two orders of magnitude increase in the average input optical power, and preferably also higher quantum energies. Prospects for this technique and its applications given modern laser capabilities and new accelerator developments are discussed

Selective photoionization of isotopic atoms with pulsed lasers

International Nuclear Information System (INIS)

Dai Changjian

1994-01-01

The dynamics of isotopically selective interactions between the radiation of three pulsed lasers and atoms with a four-levels scheme has been studied. Starting from the time-dependent Schroedinger equation with the rotating-wave approximation, authors applied Sylvester theorem to the dynamic equations associated with near-and off-resonant excitations, respectively. Authors obtained the explicit expressions for the four-levels occupation probabilities. The analytic treatment explored the properties of coherent oscillations occurred in the atomic excitation processes with intense monochromatic lasers. The conditions under which the population inversion takes place are derived from near-resonant excitations. The criteria to select the basic parameters of pulsed lasers involved in the process are also provided

Fundamental study on laser manipulation of contamination particles with determining shape, size and species

International Nuclear Information System (INIS)

Shimizu, Isao; Fujii, Taketsugu

1995-01-01

It has been desired to eliminate or collect the contamination particles of radioisotope in each sort of species or shape and size non-invasively. The shape and size of particle can be determined from the shape and distribution of diffraction pattern of particle in the parallel laser beam, the species of particle can be discriminated by the fluorescence from resonance of laser beam, or by the laser Raman scattering, and the particle suspended in the air or falling down in a vacuum can be levitated against the gravity and trapped by the radiation force and the trapping force of the focussed laser beam in the atmosphere or in a vacuum. For the purpose of the non-invasive manipulation of contamination particles, the laser manipulation technique, image processing technique with Multiplexed Matched Spatial Filter and the determination technique of laser Raman scattering or fluorescence from resonance of laser light were combined in the experiments. The shape, size and species of particles trapped in the focal plane of focused Ar laser beam can be determined simultaneously and instantaneously from the shape and intensity distributions of diffraction patterns of the particles in the irradiation of parallel coherent beam of He-Ne laser, and fluorescence from the resonance of YAG laser beam with variable wave length. In this research, a new technique is proposed to manipulate non-invasively the contamination particles determined with the shape, size and species in the atmosphere or in a vacuum, by laser beam. (author)

Laser doppler perfusion imaging

International Nuclear Information System (INIS)

Waardell, K.

1992-01-01

Recording of tissue perfusion is important in assessing the influence of peripheral vascular diseases on the microcirculation. This thesis reports on a laser doppler perfusion imager based on dynamic light scattering in tissue. When a low power He-Ne laser beam sequentally scans the tissue, moving blood cells generate doppler components in the back-scattered light. A fraction of this light is detected by a photodetector and converted into an electrical signal. In the processor, a signal proportional to the tissue perfusion at each measurement site is calculated and stored. When the scanning procedure is completed, a color-coded perfusion image is presented on a monitor. To convert important aspects of the perfusion image into more quantitative parameters, data analysis functions are implemented in the software. A theory describing the dependence of the distance between individual measurement points and detector on the system amplification factor is proposed and correction algorithms are presented. The performance of the laser doppler perfusion imager was evaluated using a flow simulator. A linear relationship between processor output signal and flow through the simulator was demonstrated for blood cell concentrations below 0.2%. The median sampling depth of the laser beam was simulated by a Monte Carlo technique and estimated to 235 μm. The perfusion imager has been used in the clinic to study perfusion changes in port wine stains treated with argon laser and to investigate the intensity and extension of the cutaneous axon reflex response after electrical nerve stimulation. The fact that perfusion can be visualized without touching the tissue implies elimination of sterilization problems, thus simplifying clinical investigations of perfusion in association with diagnosis and treatment of peripheral vascular diseases. 22 refs

Laser spectroscopy on organic molecules.

Science.gov (United States)

Imasaka, T

1996-06-01

Various laser spectrometric methods have been developed until now. Especially, laser fluorometry is most sensitive and is frequently combined with a separation technique such as capillary electrophoresis. For non-fluorescent compounds, photothermal spectrometry may be used instead. A diode laser is potentially useful for practical trace analysis, because of its low cost and long-term trouble-free operation. On the other hand, monochromaticity of the laser is essential in high-resolution spectrometry, e.g. in low temperature spectrometry providing a very sharp spectral feature. Closely-related compounds such as isomers can easily be differentiated, and information for assignment is obtained from the spectrum. Multiphoton ionization mass spectrometry is useful for soft ionization, providing additional information concerned with molecular weight and chemical structure. A short laser pulse with a sufficient energy is suitable for rapid heating of the solid surface. A matrix-assisted laser desorption/ion-ization technique is recently employed for introduction of a large biological molecule into a vacuum for mass analysis. In the future, laser spectrometry will be developed by a combination with state-of-the-art laser technology. In the 21st century, new laser spectrometry will be developed, which may be based on revolutionary ideas or unexpected discoveries. Such studies will open new frontiers in analytical laser spectroscopy.

"Ne kreshtshenogo, ne otpetogo..." : [luuletused] / Marina Petrova

Index Scriptorium Estoniae

Petrova, Marina

2001-01-01

Sisu: "Ne kreshtshenogo, ne otpetogo..." ; "Inogo mesta vstretshi v mire net..." ; "Moi put lezhit tsherez Moskvu..." ; "Osvoboditelnaja ossen - ..." ; Pjuhtitskim aistam ; "Vesjolõje svetshi kanona..." ; Vjuga ; Materi Bozhijei Pjuhtitskoi ; "Pustõnja moja, pustõnja..." ; "Odinnadtsat let v mojo serdtse gljadjat kupola..."

Rb*Hen exciplexes in solid 4He

International Nuclear Information System (INIS)

Hofer, A.; Moroshkin, P.; Nettels, D.; Ulzega, S.; Weis, A.

2006-01-01

We report the observation of emission spectra from Rb*He n exciplexes in solid 4 He. Two different excitation channels were experimentally identified, viz., exciplex formation via laser excitation to the atomic 5P 3/2 and to the 5P 1/2 levels. While the former channel was observed before in liquid helium, on helium nanodroplets, and in helium gas by different groups, the latter creation mechanism occurs only in solid helium or in gaseous helium above 10 K. The experimental results are compared to theoretical predictions based on the extension of a model, used earlier by us for the description of Cs*He n exciplexes. We also report the observation of fluorescence from atomic rubidium in solid helium, and discuss striking differences between the spectroscopic features of Rb-He and Cs-He systems

The potential of dual-energy virtual monochromatic imaging in reducing renal cyst pseudoenhancement. A phantom study

International Nuclear Information System (INIS)

Yamada, Sachiko; Ueguchi, Takashi; Ukai, Isao; Nagai, Yumiko; Yamakawa, Masanobu; Shimosegawa, Eku; Shimazu, Takeshi; Hatazawa, Jun

2012-01-01

Renal cyst pseudoenhancement, an artifactual increase of computed tomography (CT) attenuation for cysts with increased iodine concentrations in the renal parenchyma, complicates the classification of cysts and may thus lead to the mischaracterization of a benign non-enhancing lesion as an enhancing mass. The purpose of this study was to use a phantom model to assess the ability of dual-energy virtual monochromatic imaging to reduce renal pseudoenhancement. A water-filled cylindrical cyst model suspended in varying concentrations of iodine solution, to simulate varying levels of parenchymal enhancement, was scanned with a dual-energy CT scanner using the following three scanning protocols with different combinations of tube voltage: 80 and 140 kV; 80 and 140 kV with tin filter; and 100 and 140 kV with tin filter. Virtual monochromatic images were then synthesized for each dual-energy scan. Single-energy scan with a tube voltage of 120 kV was also performed to obtain polychromatic images as controls. Mean attenuation values (in Hounsfield units) of cyst proxies were measured on both polychromatic and virtual monochromatic images. Pseudoenhancement was considered to be present when the cyst attenuation level increased by more than 10 HU (Hounsfield Unit) as the background iodine concentration increased from 0.0% to 0.4%, 1.5%, or 2.5%. Our results revealed that pseudoenhancement was not observed on any of the monochromatic images, but appeared on polychromatic images at a background iodine concentration of 2.5%. We thus conclude that dual-energy virtual monochromatic images have a potential to reduce renal pseudoenhancement. (author)

Stabilization of He2(A(sup 3)Sigma(sub u)(+)) molecules in liquid helium by optical pumping for vacuum UV laser

Science.gov (United States)

Zmuidzinas, J. S. (Inventor)

1978-01-01

A technique is disclosed for achieving large populations of metastable spin-aligned He2(a 3 Sigma u +) molecules in superfluid helium to obtain lasing in the vacuum ultraviolet wavelength regime around 0.0800 micron m by electronically exciting liquid (superfluid) helium with a comparatively low-current electron beam and spin aligning the metastable molecules by means of optical pumping with a modestly-powered (100mW) circularly-polarized continuous wave laser operating at, for example, 0.9096 or 0.4650 micron m. Once a high concentration of spin-aligned He2 (a 3 Sigma u +) is achieved with lifetimes of a few milliseconds, a strong microwave signal destroys the spin alignment and induces a quick collisional transition of He2 (a 3 Sigma u +) molecules to the a 1 Sigma u + state and thereby a lasing transition to the X 1 Sigma g + state.

Atomic interaction with quantum fluid clusters: cross-jet deflection of 3He- and 4He-clusters

International Nuclear Information System (INIS)

Gspann, J.; Vollmar, H.

1977-01-01

The authors have studied earlier the velocity dependence of the total scattering of Cs atomic beams by 4 He-cluster beams, in comparison with corresponding experiments with N 2 - and Ne-cluster beams. Only with the 4 He-cluster beams a deficiency in the effective total scattering compared to the expected behaviour has been observed which was largest near 200 m/s of relative velocity. However, it is difficult to estimate, and therefore still a matter of investigation, to which extent this effect could be attributed to the presence of a small amount of uncondensed helium atoms in the cluster beam. In this paper a first account is given on an experimental study of the drag coefficients in free molecular flow of helium clusters of either isotope. The drag coefficients describe the respective efficiencies of linear momentum transfer onto the clusters and are found to be appreciably lower for helium than for nitrogen clusters which is ascribed to the fluidity of the helium clusters. (Auth.)

Development of polarized {sup 3}He filter for polarized neutron experiment

Energy Technology Data Exchange (ETDEWEB)

Sakai, K.; Sato, H.; Yoshimi, A.; Asahi, K. [Tokyo Inst. of Tech. (Japan). Faculty of Science; Masuda, Y.; Muto, S.; Ishimoto, S.; Morimoto, K.

1996-08-01

A high-pressure polarized {sup 3}He gas cell, pumped with two diode lasers, has been developed at KEK for use as a polarizer and a spin analyzer for low energy neutrons. The polarization attained of {sup 3}He was determined through the measurement of the transmission of the unpolarized neutrons through the {sup 3}He cell. So far we obtained P{sub He}=18% at 10 atm and P{sub He}=12% at 20 atm. (author)

Inelastic neutron scattering experiments with the monochromatic imaging mode of the RITA-II spectrometer

International Nuclear Information System (INIS)

Bahl, C.R.H.; Lefmann, K.; Abrahamsen, A.B.; Ronnow, H.M.; Saxild, F.; Jensen, T.B.S.; Udby, L.; Andersen, N.H.; Christensen, N.B.; Jakobsen, H.S.; Larsen, T.; Haefliger, P.S.; Streule, S.; Niedermayer, Ch.

2006-01-01

Recently a monochromatic multiple data taking mode has been demonstrated for diffraction experiments using a RITA type cold neutron spectrometer with a multi-bladed analyser and a position-sensitive detector. Here, we show how this mode can be used in combination with a flexible radial collimator to perform real inelastic neutron scattering experiments. We present the results from inelastic powder, single crystal dispersion and single crystal constant energy mapping experiments. The advantages and complications of performing these experiments are discussed along with a comparison between the imaging mode and the traditional monochromatic focussing mode

Inelastic neutron scattering experiments with the monochromatic imaging mode of the RITA-II spectrometer

Energy Technology Data Exchange (ETDEWEB)

Bahl, C.R.H. [Department of Materials Research, Riso National Laboratory, Building 227, Frederiksborgvej 399, DK-4000 Roskilde (Denmark) and Department of Physics, Technical University of Denmark, DK-2800 Lyngby (Denmark)]. E-mail: christian.bahl@risoe.dk; Lefmann, K. [Department of Materials Research, Riso National Laboratory, Building 227, Frederiksborgvej 399, DK-4000 Roskilde (Denmark)]. E-mail: kim.lefmann@risoe.dk; Abrahamsen, A.B. [Department of Materials Research, Riso National Laboratory, Building 227, Frederiksborgvej 399, DK-4000 Roskilde (Denmark); Ronnow, H.M. [Laboratory for Neutron Scattering, Paul Scherrer Institute, CH-5232 Villigen (Switzerland); Saxild, F. [Department of Materials Research, Riso National Laboratory, Building 227, Frederiksborgvej 399, DK-4000 Roskilde (Denmark); Jensen, T.B.S. [Department of Materials Research, Riso National Laboratory, Building 227, Frederiksborgvej 399, DK-4000 Roskilde (Denmark); Udby, L. [Department of Materials Research, Riso National Laboratory, Building 227, Frederiksborgvej 399, DK-4000 Roskilde (Denmark); Andersen, N.H. [Department of Materials Research, Riso National Laboratory, Building 227, Frederiksborgvej 399, DK-4000 Roskilde (Denmark); Christensen, N.B. [Department of Materials Research, Riso National Laboratory, Building 227, Frederiksborgvej 399, DK-4000 Roskilde (Denmark); Laboratory for Neutron Scattering, Paul Scherrer Institute, CH-5232 Villigen (Switzerland); Jakobsen, H.S. [Niels Bohr Institute for Astronomy, Physics and Geophysics, University of Copenhagen, DK-2100 Copenhagen (Denmark); Larsen, T. [Niels Bohr Institute for Astronomy, Physics and Geophysics, University of Copenhagen, DK-2100 Copenhagen (Denmark); Haefliger, P.S. [Laboratory for Neutron Scattering, Paul Scherrer Institute, CH-5232 Villigen (Switzerland); Streule, S.; Niedermayer, Ch. [Laboratory for Neutron Scattering, Paul Scherrer Institute, CH-5232 Villigen (Switzerland)

2006-05-15

Recently a monochromatic multiple data taking mode has been demonstrated for diffraction experiments using a RITA type cold neutron spectrometer with a multi-bladed analyser and a position-sensitive detector. Here, we show how this mode can be used in combination with a flexible radial collimator to perform real inelastic neutron scattering experiments. We present the results from inelastic powder, single crystal dispersion and single crystal constant energy mapping experiments. The advantages and complications of performing these experiments are discussed along with a comparison between the imaging mode and the traditional monochromatic focussing mode.

Low energy helium-neon laser in the prevention of oral mucositis in patients undergoing bone marrow transplant: results of a double blind randomized trial

International Nuclear Information System (INIS)

Cowen, Didier; Tardieu, Corrine; Schubert, Mark; Peterson, Douglas; Resbeut, Michel; Faucher, Catherine; Franquin, Jean-Claude

1997-01-01

Purpose: To evaluate the efficiency of Helium-Neon (He-Ne) laser in the prevention of oral mucositis induced by high dose chemoradiotherapy before autologous bone marrow transplantation (BMT). Methods and Materials: Between 1993 and 1995, 30 consecutive patients receiving an autologous peripheral stem-cell or bone marrow transplant (BMT) after high dose chemoradiotherapy were randomized to possibly receive prophylactic laser to the oral mucosa after giving informed consent. Chemotherapy consisted of cyclophosphamide, 60 mg/kg intravenously (IV) on day (d)-5 and d-4 in 27 cases, or melphalan 140 mg/kg IV on d-4 in three cases. Total body irradiation (TBI) consisted of 12 Gy midplane dose in six fractions (4 Gy/day for three days). He-Ne laser (632.8 nm wavelength, power 60 mW) applications were performed daily from d-5 to d-1 on five anatomic sites of the oral mucosa. Oral examination was performed daily from d0 to d + 20. Mucositis was scored according to an oral exam guide with a 16 item scale of which four were assessed by the patients themselves. Mean daily self assessment scores for oral pain, ability to swallow and oral dryness were measured. A daily mucositis index (DMI) and a cumulative oral mucositis score (COMS) were established. Requirement for narcotics and parenteral nutrition was recorded. Results: The COMS was significantly reduced among laser treated (L+) patients (p = 0.04). The improvement of DMI in L+ patients was also statistically significant (p < 0.05) from d + 2 to d + 7. Occurrence and duration of grade III oral mucositis were reduced in L+ patients (p = 0.01). Laser applications reduced oral pain as assessed by patients (p = 0.05) and L+ patients required less morphine (p = 0.05). Xerostomia and ability to swallow were improved among the L+ patients (p = 0.005 and p = 0.01, respectively). Requirement for parenteral nutrition was not reduced (p = NS). Conclusion: Helium-Neon laser treatment was well tolerated, feasible in all cases, and

Three-dimensional monochromatic x-ray CT

Science.gov (United States)

Saito, Tsuneo; Kudo, Hiroyuki; Takeda, Tohoru; Itai, Yuji; Tokumori, Kenji; Toyofuku, Fukai; Hyodo, Kazuyuki; Ando, Masami; Nishimura, Ktsuyuki; Uyama, Chikao

1995-08-01

In this paper, we describe a 3D computed tomography (3D CT) using monochromatic x-rays generated by synchrotron radiation, which performs a direct reconstruction of 3D volume image of an object from its cone-beam projections. For the develpment of 3D CT, scanning orbit of x-ray source to obtain complete 3D information about an object and corresponding 3D image reconstruction algorithm are considered. Computer simulation studies demonstrate the validities of proposed scanning method and reconstruction algorithm. A prototype experimental system of 3D CT was constructed. Basic phantom examinations and specific material CT image by energy subtraction obtained in this experimental system are shown.

Kinetic analysis of rare gas metastable production and optically pumped Xe lasers

Science.gov (United States)

Demyanov, A. V.; Kochetov, I. V.; Mikheyev, P. A.; Azyazov, V. N.; Heaven, M. C.

2018-01-01

Optically pumped all-rare-gas lasers use metastable rare gas atoms as the lasing species in mixtures with He or Ar buffer gas. The metastables are generated in a glow discharge, and we report model calculations for the optimal production of Ne*, Ar*, Kr* and Xe*. Discharge efficiency was estimated by solving the Boltzmann equation. Laser efficiency, gain and output power of the CW optically pumped Xe laser were assessed as functions of heavier rare gas content, pressure, optical pump intensity and the optical path length. It was found that, for efficient operation the heavier rare gas content has to be of the order of one percent or less, and the total pressure—in the range 0.3-1.5 atm. Output power and specific discharge power increase approximately linearly with pump intensity over the output range from 300-500 W cm-2. Ternary mixtures Xe:Ar:He were found to be the most promising. Total laser efficiency was found to be nearly the same for pumping the 2p8 or 2p9 state, reaching 61%-70% for a pump intensity of ~720 W cm-2 when the Xe fraction was in the range 0.001 ÷ 0.01 and Ar fraction—0.1 ÷ 0.5. However, when the 2p8 state was pumped, the maximum total efficiency occurred at larger pressures than for pumping of the 2p9 state. The discharge power density required to sustain a sufficient Xe* number density was in the range of tens of watts per cubic centimeter for 50% Ar in the mixture.

Reply to projectile- and target-charge dependent effects in ionizing collisions of H sup + and He sup 2+ with He, Ne and Ar atoms

Energy Technology Data Exchange (ETDEWEB)

Bernardi, G.; Suarez, S.; Fainstein, P.; Garibotti, C.; Meckbach, W.; Focke, P. (Comision Nacional de Energia Atomica, San Carlos de Bariloche (Argentina). Centro Atomico Bariloche)

1990-12-28

The consistency of our previous results, for He ionization by H{sup +} and He{sub 3}{sup 2+} impact, with recent theoretical calculations is briefly commented upon. The results do not support the hypothesis of an independent saddle-point mechanism at the projectile energies studied. (author).

Two-photon excitation laser scanning microscopy of porcine nasal septal cartilage following Nd:YAG laser-mediated stress relaxation

Science.gov (United States)

Kim, Charlton C.; Wallace, Vincent P.; Rasouli, Alexandre; Coleno, Mariah L.; Dao, Xavier; Tromberg, Bruce J.; Wong, Brian J.

2000-05-01

Laser irradiation of hyaline cartilage result in stable shape changes due to temperature dependent stress relaxation. In this study, we determined the structural changes in chondrocytes within porcine nasal septal cartilage tissue over a 4-day period using a two-photon laser scanning microscope (TPM) following Nd:YAG laser irradiation (lambda equals 1.32 micrometer) using parameters that result in mechanical stress relaxation (6.0 W, 5.4 mm spot diameter). TPM excitation (780 nm) result in induction of fluorescence from endogenous agents such as NADH, NADPH, and flavoproteins in the 400 - 500 nm spectral region. During laser irradiation diffuse reflectance (from a probe HeNe laser, (lambda) equals 632.8 nm), surface temperature, and stress relaxation were measured dynamically. Each specimen received one, two, or three sequential laser exposures (average irradiation times of 5, 6, and 8 seconds). The cartilage reached a peak surface temperature of about 70 degrees Celsius during irradiation. Cartilage denatured in 50% EtOH (20 minutes) was used as a positive control. TPM was performed using a mode-locked 780 nm Titanium:Sapphire (Ti:Al203) beam with a, 63X, 1.2 N.A. water immersion objective (working distance of 200 mm) to detect the fluorescence emission from the chondrocytes. Images of chondrocytes were obtained at depths up to 150 microns (lateral resolution equals 35 micrometer X 35 micrometer). Images were obtained immediately following laser exposure, and also after 4 days in culture. In both cases, the irradiated and non-irradiated specimens do not show any discernible difference in general shape or auto fluorescence. In contrast, positive controls (immersed in 50% ethanol), show markedly increased fluorescence relative to both the native and irradiated specimens, in the cytoplasmic region.

Measurement of ejected electrons from collisions of He+ ions with He, Ne, and Ar at the intermediate energies

International Nuclear Information System (INIS)

Tokoro, Nobuhiro; Oda, Nobuo

1985-01-01

The doubly differential cross sections for electron production, differential in angle and energy of the electrons, for 5-25 keV He + impact on helium, neon and argon have been measured in the electron energy range of 2-200 eV at the ejection angles from 30 0 to 150 0 with respect to the incident ion beam. The characteristic features of continnum parts of ejected electron spectra are described for each collision system. (author)

Hyperfine Structure Measurements of Antiprotonic $^3$He using Microwave Spectroscopy

CERN Document Server

Friedreich, Susanne

The goal of this project was to measure the hyperfine structure of $\\overline{\\text{p}}^3$He$^+$ using the technique of laser-microwave-laser spectroscopy. Antiprotonic helium ($\\overline{\\text{p}}$He$^+$) is a neutral exotic atom, consisting of a helium nucleus, an electron and an antiproton. The interactions of the angular momenta of its constituents cause a hyperfine splitting ({HFS}) within the energy states of this new atom. The 3\\% of formed antiprotonic helium atoms which remain in a metastable, radiative decay-dominated state have a lifetime of about 1-3~$\\mu$s. This time window is used to do spectroscopic studies. The hyperfine structure of $\\overline{\\text{p}}^4$He$^+$ was already extensively investigated before. From these measurements the spin magnetic moment of the antiproton can be determined. A comparison of the result to the proton magnetic moment provides a test of {CPT} invariance. Due to its higher complexity the new exotic three-body system of $\\overline{\\text{p}}^3$He$^+$ is a cross-check...

Crude oil He and Ar isotopic characteristics and their geochemical significance: an example from the Gangxi oil field in the Huanghua depression

Directory of Open Access Journals (Sweden)

S. Chenpeng

2005-06-01

Full Text Available Sampled from the Gangxi oil field in the Huanghua depression, Bohaiwan Basin, the crude oil He and Ar isotopic compositions and their geochemical significance were investigated. The result shows that i the 3He/4He values of the six oil samples free from air contamination indicate a mantle helium contribution ranging between 13.9% and 32.8% and averaging 24.1%, which means that the Gangxi oil field once had a tectonic background of the mantle-derived helium input and higher geothermal flow with an average of 75.0 mWm-2; ii deduced from the 40Ar/36Ar aging effect the Gangxi oil should be derived from the Tertiary; iii water injection is the main reason for the air contamination for the Gangxi oil noble gases and the relations between 3He/4He and 4He/20Ne as well as 40Ar/36Ar and 4He/20Ne are of an applicative potential in estimating the water injection effect and the connectivity of producing formations. The search for the crude oil He and Ar isotopes provides a new approach to inferring natural gas and oil sources, tectonic backgrounds, geothermal flow and water injection effect.

Analysis of monochromatic signals by using data from the detector of Allegro gravitational waves

International Nuclear Information System (INIS)

Oliveira, Fernanda Gomes de

2010-01-01

The present work is developed in the searching for monochromatic gravitational waves signals in ALLEGRO's data. We have two procedures for data analysis based on the periodogram of Welch, which a method for the detection of monochromatic signals in the middle of noise which basically makes power spectrum estimates using averaged modified periodograms. By using this method it was possible to obtain a power spectrum for the data which reinforce peaks due to monochromatic signals. The two procedures of analysis for the years 1997 and 1999, were focused on monitoring a peak that appears in the spectral density of ALLEGRO's detector, so called 'mystery mode' (near 887 Hz). We look for variations in the frequency of the mystery mode that agree with the variation of the Doppler effect. In the rst analysis we have used by the variation of daily and annual Doppler shift. For the second one, we have only searched annual Doppler shift. We have applied the periodogram of Welch in both tests in the raw data of the detector in the search for a real signal and we found some peaks that can be candidates of gravitational radiation only the second analysis. In order to test the method we used in both analysis a simulated gravitational wave signal modulated by the Doppler effect injected in the data. We detected in both methods the artificial signal of GW simulated. Therefore we have reason to conclude that both methods are efficient in the search for monochromatic signals. (author)

Integrated Laser Ablation U/Pb and (U-Th)/He Dating of Detrital Accessory Minerals from the Naryani River, Central Nepal

Science.gov (United States)

Horne, A.; Hodges, K. V.; Van Soest, M. C.

2015-12-01

The newly developed 'laser ablation double dating' (LADD) technique, an integrated laser microprobe U/Pb and (U-Th)/He dating method, could be an exceptionally valuable tool in detrital thermochronology for identifying sedimentary provenance and evaluating the exhumation history of a source region. A recent proof-of-concept study has used LADD to successfully date both zircon and titanite crystals from the well-characterized Fish Canyon tuff, but we also believe that another accessory mineral, rutile, could be amenable to dating via the LADD technique. To continue the development of the method, we present an application of LADD to detrital zircon, titanite, and rutile from a sample collected on the lower Naryani River of central Nepal. Preliminary analyses of the sample have yielded zircon U/Pb dates ranging from 31.4 to 2405 Ma; zircon (U-Th)/He from 1.8 to 15.4 Ma; titanite U/Pb between 18 and 110 Ma; titanite (U-Th)/He between 1 and 16 Ma; rutile U/Pb from 6 to 45 Ma; and rutile (U-Th)/He from 2 to 25 Ma. In addition to the initial data, we can use Ti-in-zircon, Zr-in-titanite, and Zr-in-rutile thermometers to determine the range of possible long-term cooling rates from grains with U/Pb ages younger than collision. Thus far our results from zircon analyses imply a cooling rate of approximately 15°C/Myr; titanite analyses imply between 10 and 67°C/Myr; and rutile between 9 and 267°C/Myr. This spread in potential cooling rates, especially in the order of magnitude differences of cooling rates calculated from the rutile grains, suggests that the hinterland source regions of the Naryani river experienced dramatically different exhumation histories during Himalayan orogenisis. Ongoing analyses will expand the dataset such that we can more adequately characterize the range of possibilities represented in the sample.

Laser materials processing as manufacturing technology; Seisan gijutsu to shite no laser kako

Energy Technology Data Exchange (ETDEWEB)

Miyamoto, I. [Osaka University, Osaka (Japan)

1998-11-01

This paper describes the laser material processing. Laser is artificial light that uses the amplification based on the induced emission of light. It is very excellent in directivity and monochromaticity. The high power density and concentration characteristics of laser enable a variety of high-performance processing such as junction, removal, reforming, and addition. Excellent controllability (that facilitates the automated processing), transmission performance (the processing by energy transmission in long range space is most suitable for laser), and non-contact processing (that contains no wearing, noise, and contamination) are great advantages that the existing processing method does not have. In the wide wavelength area between ultraviolet and infrared areas, the laser that can be used for material processing is very wide over the range of the continuous oscillation to the ultra short pulse of a nanosecond order. The thermal processing accompanied by melting and evaporation as well as the non-thermal processing (quantum processing) by a photochemical reaction is also available as the type of processing. The processing used for manufacturing technology is almost thermal processing including removal, junction, reforming, and addition. The thermal processing covers the range of electronics to heavy industry. 29 refs., 12 figs., 2 tabs.

Hyperfine structure of the metastable p-barHe+ atom revealed by a laser-induced (n,l) = (37,35) → (38,34) transition

International Nuclear Information System (INIS)

Widmann, E.; Eades, J.; Yamazaki, T.

1996-11-01

A precise scan of the previously discovered laser-induced transition (n,l) = (37,35) → (38,34) in p-barHe + revealed a doublet structure with a separation of Δν HF = 1.70 ± 0.05 GHz. This new type of 'hyperfine' splitting is ascribed to the interaction of the antiproton orbital angular momentum and the electron spin. (author)

Continuous pneumothorax monitoring by remittance measurement

NARCIS (Netherlands)

Beek, J. F.; Sterenborg, H. J.; van Gemert, M. J.

1993-01-01

The feasibility of a noninvasive method, based on a remittance measurement, to monitor continuously for the occurrence of pneumothorax in neonates under ventilation, was investigated through animal experiments. Light from a He-Ne laser (632.8 nm) or a semiconductor laser (790 nm) was incident on the

IONIZED GAS KINEMATICS AT HIGH RESOLUTION. V. [Ne ii], MULTIPLE CLUSTERS, HIGH EFFICIENCY STAR FORMATION, AND BLUE FLOWS IN HE 2–10

International Nuclear Information System (INIS)

Beck, Sara; Turner, Jean; Lacy, John; Greathouse, Thomas

2015-01-01

We measured the 12.8 μm [Ne ii] line in the dwarf starburst galaxy He 2–10 with the high-resolution spectrometer TEXES on the NASA IRTF. The data cube has a diffraction-limited spatial resolution of ∼1″ and a total velocity resolution, including thermal broadening, of ∼5 km s −1 . This makes it possible to compare the kinematics of individual star-forming clumps and molecular clouds in the three dimensions of space and velocity, and allows us to determine star formation efficiencies. The kinematics of the ionized gas confirm that the starburst contains multiple dense clusters. From the M/R of the clusters and the ≃30%–40% star formation efficiencies, the clusters are likely to be bound and long lived, like globulars. Non-gravitational features in the line profiles show how the ionized gas flows through the ambient molecular material, as well as a narrow velocity feature, which we identify with the interface of the H ii region and a cold dense clump. These data offer an unprecedented view of the interaction of embedded H ii regions with their environment

A noncontact laser system for measuring soil surface topography

International Nuclear Information System (INIS)

Huang, C.; White, I.; Thwaite, E.G.; Bendeli, A.

1988-01-01

Soil surface topography profoundly influences runoff hydrodynamics, soil erosion, and surface retention of water. Here we describe an optical noncontact system for measuring soil surface topography. Soil elevation is measured by projecting a laser beam onto the surface and detecting the position of the interception point. The optical axis of the detection system is oriented at a small angle to the incident beam. A low-power HeNe (Helium-Neon) laser is used as the laser source, a photodiode array is used as the laser image detector and an ordinary 35-mm single lens reflex camera provides the optical system to focus the laser image onto the diode array. A wide spectrum of measurement ranges (R) and resolutions are selectable, from 1 mm to 1 m. These are determined by the laser-camera distance and angle, the focal length of the lens, and the sensing length of the diode array and the number of elements (N) contained in the array. The resolution of the system is approximately R/2N. We show for the system used here that this resolution is approximately 0.2%. In the configuration selected, elevation changes of 0.16 mm could be detected over a surface elevation range of 87 mm. The sampling rate of the system is 1000 Hz, which permits soil surfaces to be measured at speeds of up to 1 m s −1 with measurements taken at 1-mm spacing. Measurements of individual raindrop impacts on the soil and of soil surfaces before and after rain show the versatility of the laser surface profiler, which has applications in studies of erosion processes, surface storage and soil trafficability

Photo-double ionisation of the Ne 2s studied in equal-energy-sharing condition at 20 eV above threshold

Energy Technology Data Exchange (ETDEWEB)

Bolognesi, P. [CNR-IMIP, Area della Ricerca di Roma 1, CP10, 00016 Monterotondo Scalo (Italy); Otranto, S. [CONICET and Depto. de Fisica, Universidad Nacional del Sur, 8000 Bahia Blanca (Argentina); Garibotti, C.R. [CONICET and Centro Atomico Bariloche, 8400 S.C. de Bariloche (Argentina); Flammini, R. [CNR-IMIP, Area della Ricerca di Roma 1, CP10, 00016 Monterotondo Scalo (Italy); Alberti, G. [CNR-IMIP, Area della Ricerca di Roma 1, CP10, 00016 Monterotondo Scalo (Italy); Avaldi, L. [CNR-IMIP, Area della Ricerca di Roma 1, CP10, 00016 Monterotondo Scalo (Italy)]. E-mail: lorenzo.avaldi@imip.cnr.it

2005-06-15

The triple differential cross-section (TDCS) for the photo-double ionisation of Ne leading to the Ne{sup 2+}(2s{sup -2}2p{sup 6}) has been measured 20 eV above threshold in equal-energy-sharing conditions. The results are compared with the recently introduced SC3 model, which can be used to study targets different from He since it allows an easy implementation with different initial-state wavefunctions.

Photo-stimulatory effect of low energy helium-neon laser irradiation on excisional diabetic wound healing dynamics in wistar rats

Directory of Open Access Journals (Sweden)

Maiya Arun

2009-01-01

Full Text Available Background: Generally, the significances of laser photo stimulation are now accepted, but the laser light facilitates wound healing and tissue repair remains poorly understood. Aims: We have examined the hypothesis that the laser photo stimulation can enhance the collagen production in diabetic wounds using the excision wound model in the Wistar rat model. Methods: The circular wounds were created on the dorsum of the back of the animals. The animals were divided into two groups. The study group (N = 24 wound was treated with 632.8 nm He-Ne laser at a dose of 3-9J/cm 2 for 5 days a week until the wounds healed completely. The control group was sham irradiated. Result: A significant increase in the hydroxyproline content and reduction in the wound size were observed in the study group. The pro-healing actions seem to be due to increased collagen deposition as well as better alignment and maturation. Conclusion: The biochemical analysis and clinical observation suggested that 3-6 J/cm 2 laser photo stimulation facilitates the tissue repair process by accelerating collagen production in diabetic wound healing.

Single source dual energy CT: What is the optimal monochromatic energy level for the analysis of the lung parenchyma?

Energy Technology Data Exchange (ETDEWEB)

Ohana, M., E-mail: mickael.ohana@gmail.com [iCube Laboratory, Université de Strasbourg/CNRS, UMR 7357, 67400 Illkirch (France); Service de Radiologie B, Nouvel Hôpital Civil – Hôpitaux Universitaires de Strasbourg, 1 place de l’hôpital, 67000 Strasbourg (France); Labani, A., E-mail: aissam.labani@chru-strasbourg.fr [Service de Radiologie B, Nouvel Hôpital Civil – Hôpitaux Universitaires de Strasbourg, 1 place de l’hôpital, 67000 Strasbourg (France); Severac, F., E-mail: francois.severac@chru-strasbourg.fr [Département de Biostatistiques et d’Informatique Médicale, Hôpital Civil – Hôpitaux Universitaires de Strasbourg,1 place de l’hôpital, 67000 Strasbourg (France); Jeung, M.Y., E-mail: Mi-Young.Jeung@chru-strasbourg.fr [Service de Radiologie B, Nouvel Hôpital Civil – Hôpitaux Universitaires de Strasbourg, 1 place de l’hôpital, 67000 Strasbourg (France); Gaertner, S., E-mail: Sebastien.Gaertner@chru-strasbourg.fr [Service de Médecine Vasculaire, Nouvel Hôpital Civil – Hôpitaux Universitaires de Strasbourg,1 place de l’hôpital, 67000 Strasbourg (France); and others

2017-03-15

Highlights: • Lung parenchyma aspect varies with the monochromatic energy level in spectral CT. • Optimal diagnostic and image quality is obtained at 50–55 keV. • Mediastinum and parenchyma could be read on the same monochromatic energy level. - Abstract: Objective: To determine the optimal monochromatic energy level for lung parenchyma analysis in spectral CT. Methods: All 50 examinations (58% men, 64.8 ± 16yo) from an IRB-approved prospective study on single-source dual energy chest CT were retrospectively included and analyzed. Monochromatic images in lung window reconstructed every 5 keV from 40 to 140 keV were independently assessed by two chest radiologists. Based on the overall image quality and the depiction/conspicuity of parenchymal lesions, each reader had to designate for every patient the keV level providing the best diagnostic and image quality. Results: 72% of the examinations exhibited parenchymal lesions. Reader 1 picked the 55 keV monochromatic reconstruction in 52% of cases, 50 in 30% and 60 in 18%. Reader 2 chose 50 keV in 52% cases, 55 in 40%, 60 in 6% and 40 in 2%. The 50 and 55 keV levels were chosen by at least one reader in 64% and 76% of all patients, respectively. Merging 50 and 55 keV into one category results in an optimal setting selected by reader 1 in 82% of patients and by reader 2 in 92%, with a 74% concomitant agreement. Conclusion: The best image quality for lung parenchyma in spectral CT is obtained with the 50–55 keV monochromatic reconstructions.

Development of transient collisional excitation x-ray laser with ultra short-pulse laser

International Nuclear Information System (INIS)

Kado, Masataka; Kawachi, Tetsuya; Hasegawa, Noboru; Tanaka, Momoko; Sukegawa, Kouta; Nagashima, Keisuke; Kato, Yoshiaki

2001-01-01

We have observed lasing on Ne-like 3s-3p line from titanium (32.4 nm), Ni-like 4p-4d line from silver (13.9 nm) and tin (11.9 nm) with the transient collisional excitation (TCE) scheme that uses combination of a long pre-pulse (∼ns) and a short main pulse (∼ps). A gain coefficient of 23 cm -1 was measured for plasma length up to 4 mm with silver slab targets. We have also observed lasing on Ne-like and Ni-like lines with new TCE scheme that used pico-seconds laser pulse to generate plasma and observed strong improvement of x-ray laser gain coefficient. A gain coefficient of 14 cm -1 was measured for plasma length up to 6 mm with tin targets. (author)

Infrared laser-induced chemical reactions

International Nuclear Information System (INIS)

Katayama, Mikio

1978-01-01

The experimental means which clearly distinguishes between infrared ray-induced reactions and thermal reactions has been furnished for the first time when an intense monochromatic light source has been obtained by the development of infrared laser. Consequently, infrared laser-induced chemical reactions have started to develop as one field of chemical reaction researches. Researches of laser-induced chemical reactions have become new means for the researches of chemical reactions since they were highlighted as a new promising technique for isotope separation. Specifically, since the success has been reported in 235 U separation using laser in 1974, comparison of this method with conventional separation techniques from the economic point of view has been conducted, and it was estimated by some people that the laser isotope separation is cheaper. This report briefly describes on the excitation of oscillation and reaction rate, and introduces the chemical reactions induced by CW laser and TEA CO 2 laser. Dependence of reaction yield on laser power, measurement of the absorbed quantity of infrared ray and excitation mechanism are explained. Next, isomerizing reactions are reported, and finally, isotope separation is explained. It was found that infrared laser-induced chemical reactions have the selectivity for isotopes. Since it is evident that there are many examples different from thermal and photo-chemical reactions, future collection of the data is expected. (Wakatsuki, Y.)

Laser Assisted Free-Free Transition in Electron - Atom Collision

Science.gov (United States)

Sinha, C.; Bhatia, A. K.

2011-01-01

Free-free transition is studied for electron-Hydrogen atom system in ground state at very low incident energies in presence of an external homogeneous, monochromatic and linearly polarized laser field. The incident electron is considered to be dressed by the laser in a non perturbative manner by choosing the Volkov solutions in both the channels. The space part of the scattering wave function for the electron is solved numerically by taking into account the effect of electron exchange, short range as well as of the long range interactions. Laser assisted differential as well as elastic total cross sections are calculated for single photon absorption/emission in the soft photon limit, the laser intensity being much less than the atomic field intensity. A strong suppression is noted in the laser assisted cross sections as compared to the field free situations. Significant difference is noted in the singlet and the triplet cross sections.

Monochromaticity of optical radiation of Smith-Purcell generated by electron beam with 75 keV energy

International Nuclear Information System (INIS)

Adishchev, Yu.N.; Vukolov, A.V.; Karlovets, D.V.; Potylitsyn, A.P.; Kube, G.

2005-01-01

The monochromatism of the Smith-Purcell optical radiation generated by a 75-keV electron beam with a final emittance of ε = 0.65 x 10 -4 mm rad that passes over an optical grating with a period of D = 0.833 μm has been analyzed. It has been shown that the monochromatism (line width) of the Smith-Purcell radiation is determined not only by the angular aperture of a monochromator but also by the divergence of the electron beam [ru

Sodium source development for pulsed power driven, photopumped NA/NE x-ray laser experiments

International Nuclear Information System (INIS)

Burkhalter, P.G.; Cooperstein, G.; Mosher, D.; Ottinger, P.F.; Scherrer, V.E.; Stephanakis, S.J.; Young, F.C.; Hinshelwood, D.D.; Mehlman, G.; Welch, B.L.; Jones, W.D.

1988-01-01

A sodium plasma source is being developed for a resonant photopumping x-ray laser scheme in which the 11A 1s 2 - 1s2rho 1 P 1 line in heliumlike Na X is used to pump the Ne IX n=4 singlet level. In their experiment the NRL Gamble II generator is used to produce two z-pinch plasmas in a side-by-side geometry. The sodium plasma is produced on axis and conducts the full 1 MA machine current. A fraction of this current returns through a neon gas puff located 5 cm from the sodium. This separation is determined by the need to prevent the plasmas from mixing and the need to have each plasma's azimuthal magnetic field as symmetric as possible. A minimum separation is desirable to increase coupling efficiency. To improve the pump source, a more confined source of pure sodium involving a coaxial plasma gun is being developed. They are currently studying both the operation of this source on a test stand and implosions of the resulting plasma on Gamble II. In initial experiments aluminum is substituted for sodium. Test stand diagnostics include photodiodes, witness plates, and current monitors designed to investigate the early motion of the annular plasma. Results from test stand and Gamble II experiments with both aluminum and sodium, as well as sodium handling techniques, are presented

Interferogram reduction and interpretation as applied to the optical analysis of the 10 kJ LASL laser fusion system

International Nuclear Information System (INIS)

Viswanathan, V.K.; Hall, W.S.; Liberman, I.; Lawrence, G.

1978-01-01

The LASL 10 kJ Eight-Beam CO 2 Laser Fusion System, currently under construction, has approximately one hundred optical elements per beam. The nominal system is diffraction limited and degradations in performance are primarily caused by imperfect components as well as alignment errors. Consequently, analysis and predictions for the system are very much dependent on the proper description of the imperfect components. The approach taken at LASL has been to characterize the components interferometrically. Interferograms of the various components are made at the 633 nm He--Ne wavelength. Detailed results of the analysis for one complete leg of the eight-beam system is presented

Laser Spectroscopy of Antiprotonic Helium Atoms

CERN Multimedia

2002-01-01

%PS205 %title\\\\ \\\\Following the discovery of metastable antiprotonic helium atoms ($\\overline{p}He^{+} $) at KEK in 1991, systematic studies of their properties were made at LEAR from 1991 to 1996. In the first two years the lifetime of $\\overline{p}He^{+}$ in liquid and gaseous helium at various temperatures and pressures was measured and the effect of foreign gases on the lifetime of these atoms was investigated. Effects were also discovered which gave the antiproton a 14\\% longer lifetime in $^4$He than in $^3$He, and resulted in important differences in the shape of the annihilation time spectra in the two isotopes.\\\\ \\\\Since 1993 laser spectroscopy of the metastable $\\overline{p}He^{+}$ atoms became the main focus of PS205. Transitions were stimulated between metastable and non-metastable states of the $\\overline{p}He^{+}$ atom by firing a pulsed dye laser beam into the helium target every time an identified metastable atom was present (Figure 1). If the laser frequency matched the transition energy, the...

Ionization and scintillation produced by relativistic Au, He and H ions in liquid argon

Energy Technology Data Exchange (ETDEWEB)

Shibamura, E; Masuda, K; Crawford, H J; Engelage, J M; Doke, T; Hitachi, A; Kikuchi, J; Flores, I; Lindstrom, P J; Ogura, K

1987-10-15

We have measured ionization and scintillation produced by relativistic ions of Au, He and H in liquid argon. The sum of ionization signal and scintillation signal per unit energy deposition is the same for He and H ions, which is also the same as that for relativistic Ne, Fe and La ions previously measured. We have found that quenching occurs when liquid argon is irradiated by relativistic Au ions and that the sum per unit energy deposition for the Au ions is 70-76% of that for the other ions mentioned above.

Classical and ablative Richtmyer-Meshkov instability and other ICF-relevant plasma flows diagnosed with monochromatic x-ray imaging

International Nuclear Information System (INIS)

Aglitskiy, Y; Metzler, N; Karasik, M; Velikovich, A L; Zalesak, S T; Schmitt, A J; Serlin, V; Weaver, J; Obenschain, S P; Gardner, J H

2008-01-01

In inertial confinement fusion (ICF) and high-energy density physics (HEDP), the most important manifestations of the hydrodynamic instabilities and other mixing processes involve lateral motion of the accelerated plasmas. In order to understand the experimental observations and to advance the numerical simulation codes to the point of predictive capability, it is critically important to accurately diagnose the motion of the dense plasma mass. The most advanced diagnostic technique recently developed for this purpose is the monochromatic x-ray imaging that combines large field of view with high contrast, high spatial resolution and large throughput, ensuring high temporal resolution at large magnification. Its application made it possible for the experimentalists to observe for the first time important hydrodynamic effects that trigger compressible turbulent mixing in laser targets, such as ablative Richtmyer-Meshkov (RM) instability, feedout, interaction of an RM-unstable interface with shock and rarefaction waves. It also helped to substantially improve the accuracy of diagnosing many other important plasma flows, ranging from laser-produced jets to electromagnetically driven wires in a Z-pinch, and to test various methods suggested for mitigation of the Rayleigh-Taylor instability. We will review the results obtained with the aid of this technique in ICF-HEDP studies at the Naval Research Laboratory and the prospects of its future applications.