Evaluation of gamma-ray intensities

International Nuclear Information System (INIS)

Yoshizawa, Yasukazu; Inoue, Hikaru; Hoshi, Masaharu; Shizuma, Kiyoshi; Iwata, Yosei.

1978-03-01

Results of literature survey and evaluation of relative intensities and intensities per decay of gamma rays are presented. Evaluations were made for 22 Na, 24 Na, 46 Sc, 48 Sc, 48 V, 54 Mn, 57 Co, 60 Co, 85 Sr, 88 Y, 95 Nb, 95 Zr, sup(108m)Ag, 134 Cs, 137 Cs, 144 Ce, 144 Pr, 203 Hg, and 207 Bi. For eight of the nuclides, the half-lives were also evaluated. (auth.)

Photoneutron intensity variation with field size around radiotherapy linear accelerator 18-MeV X-ray beam

Energy Technology Data Exchange (ETDEWEB)

Al-Ghamdi, H.; Fazal-ur-Rehman [Physics Department, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Al-Jarallah, M.I. [Physics Department, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia)], E-mail: mibrahim@kfupm.edu.sa; Maalej, N. [Physics Department, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia)

2008-08-15

In X-ray radiotherapy accelerators, neutrons are produced mainly by ({gamma},n) reaction when high energy X-rays interact with high Z materials of the linear accelerator head. These materials include the lead (Pb) used as shielding in the collimator, tungsten (W) target used for the production of X-rays and iron (Fe) in the accelerator head. These unwanted neutrons contaminate the therapeutic beam and contribute to the patient dose during the treatment of a cancer patient. Knowing the neutron distribution around the radiotherapy accelerator is therefore desired. CR-39 nuclear track detectors (NTDs) were used to study the variation of fast and thermal neutron relative intensities around an 18 MeV linear accelerator X-ray beam with the field sizes of 0, 10x10, 20x20, 30x30 and 40x40cm{sup 2}. For fast neutron detection, bare NTDs were used. For thermal neutron detection, NTDs were covered with lithium tetra borate (Li{sub 2}B{sub 4}O{sub 7}) converters. The NTDs were placed at different locations in the direction perpendicular to the treatment couch (transversal) and in the direction parallel to the treatment couch (longitudinal) with respect to the isocenter of the accelerator. The fast neutron relative intensity is symmetrical about the beam axis and exhibits an exponential-like drop with distance from the isocenter of the accelerator for all the field sizes. At the primary beam (isocenter), the relative fast neutron intensity is highest for 40x40cm{sup 2} field size and decreases linearly with the decrease in the field size. However, fast neutron intensities do not change significantly with beam size for the measurements outside the primary beam. The fast neutron intensity in the longitudinal direction outside the primary beam decreases linearly with the field size. The thermal neutron intensity, at any location, was found to be almost independent of the field size.

Observations of recurrent cosmic ray decreases during solar cycles 22 and 23

International Nuclear Information System (INIS)

Dunzlaff, P.; Heber, B.; Kopp, A.; Rother, O.; Mueller-Mellin, R.; Klassen, A.; Gomez-Herrero, R.; Wimmer-Schweingruber, R.

2008-01-01

During solar cycle 22, the modulation of several hundred MeV galactic cosmic rays (GCRs) by recurrent and transient cosmic ray decreases was observed by the Ulysses spacecraft on its descent towards the solar south pole. In solar cycle 23, Ulysses repeated this trajectory segment during a similar phase of the solar cycle, but with opposite heliospheric magnetic field polarity. Since cosmic ray propagation in the heliosphere should depend on drift effects, we determine in this study the latitudinal distribution of the amplitude of recurrent cosmic ray decreases in solar cycles 22 and 23. As long as we measure the recurrent plasma structures in situ, we find that these decreases behave nearly the same in both cycles. Measurements in the fast solar wind, however, show differences: in cycle 22 (A>0) the recurrent cosmic ray decreases show a clear maximum near 25 and are still present beyond 40 , whereas we see in cycle 23 (A<0) neither such a pronounced maximum nor significant decreases above 40 . In other words: the periodicity in the cosmic ray intensity, which can be clearly seen in the slow solar wind, appears to vanish there. Theoretical models for drift effects, however, predict quite the opposite behaviour for the two solar cycles. To closer investigate this apparent contradiction, we first put the visual inspection of the data onto a more solid basis by performing a detailed Lomb (spectral) analysis. The next step consists of an analysis of the resulting periodicities at 1 AU in order to distinguish between spatial and temporal variations, so that we can obtain statements about the question in how far there is a correlation between the in-situ data at 1 AU and those measured by Ulysses at larger latitudes. We find a good correlation being present during cycle 22, but not for cycle 23. As one potential explanation for this behaviour, we suggest the difference in the coronal hole structures between the cycles 22 and 23 due to a large, stable coronal hole

K and L X-ray emission intensities of some radionuclides

Energy Technology Data Exchange (ETDEWEB)

Verma, H R; Pal, D [Punjabi Univ., Patiala (India). Dept. of Physics

1985-01-01

The K and L x-ray emission intensities per 100 disintegrations have been calculated for some radionuclides using the latest adopted data for gamma-ray intensities, electron capture and internal conversion coefficients for the parent nuclides, fluorescence yield values, Coster-Kronig transition probabilities, average total number of primary L shell vacancies produced in the decay of K shell vacancies and emission rates for various shells and subshells for the daughter nuclei. The results are in good agreement with theoretical and experimental values for the K x-ray intensities. There are no experimental results available to compare with the present calculations for the L x-ray intensities; however, there is a marked discrepancy in the L..cap alpha.. and L..beta.. intensities available on the basis of theoretical estimates.

Valence electronic structure of Ni in Ni Si alloys from relative K X-ray intensity studies

Science.gov (United States)

Kalayci, Y.; Aydinuraz, A.; Tugluoglu, B.; Mutlu, R. H.

2007-02-01

The Kβ-to-Kα X-ray intensity ratio of Ni in Ni 3Si, Ni 2Si and NiSi has been determined by energy dispersive X-ray fluorescence technique. It is found that the intensity ratio of Ni decreases from pure Ni to Ni 2Si and then increases from Ni 2Si to NiSi, in good agreement with the electronic structure calculations cited in the literature. We have also performed band structure calculations for pure Ni in various atomic configurations by means of linear muffin-tin orbital method and used this data with the normalized theoretical intensity ratios cited in the literature to estimate the 3d-occupation numbers of Ni in Ni-Si alloys. It is emphasized that investigation of alloying effect in terms of X-ray intensity ratios should be carried out for the stoichiometric alloys in order to make reliable and quantitative comparisons between theory and experiment in transition metal alloys.

Compton spectra of atoms at high x-ray intensity

Science.gov (United States)

Son, Sang-Kil; Geffert, Otfried; Santra, Robin

2017-03-01

Compton scattering is the nonresonant inelastic scattering of an x-ray photon by an electron and has been used to probe the electron momentum distribution in gas-phase and condensed-matter samples. In the low x-ray intensity regime, Compton scattering from atoms dominantly comes from bound electrons in neutral atoms, neglecting contributions from bound electrons in ions and free (ionized) electrons. In contrast, in the high x-ray intensity regime, the sample experiences severe ionization via x-ray multiphoton multiple ionization dynamics. Thus, it becomes necessary to take into account all the contributions to the Compton scattering signal when atoms are exposed to high-intensity x-ray pulses provided by x-ray free-electron lasers (XFELs). In this paper, we investigate the Compton spectra of atoms at high x-ray intensity, using an extension of the integrated x-ray atomic physics toolkit, xatom. As the x-ray fluence increases, there is a significant contribution from ionized electrons to the Compton spectra, which gives rise to strong deviations from the Compton spectra of neutral atoms. The present study provides not only understanding of the fundamental XFEL-matter interaction but also crucial information for single-particle imaging experiments, where Compton scattering is no longer negligible. , which features invited work from the best early-career researchers working within the scope of J. Phys. B. This project is part of the Journal of Physics series’ 50th anniversary celebrations in 2017. Sang-Kil Son was selected by the Editorial Board of J. Phys. B as an Emerging Leader.

Multi-keV X-ray area source intensity at SGII laser facility

Science.gov (United States)

Wang, Rui-rong; An, Hong-hai; Xie, Zhi-yong; Wang, Wei

2018-05-01

Experiments for investigating the feasibility of multi-keV backlighters for several different metallic foil targets were performed at the Shenguang II (SGII) laser facility in China. Emission spectra in the energy range of 1.65-7.0 keV were measured with an elliptically bent crystal spectrometer, and the X-ray source size was measured with a pinhole camera. The X-ray intensity near 4.75 keV and the X-ray source size for titanium targets at different laser intensity irradiances were studied. By adjusting the total laser energy at a fixed focal spot size, laser intensity in the range of 1.5-5.0 × 1015 W/cm2, was achieved. The results show that the line emission intensity near 4.75 keV and the X-ray source size are dependent on the laser intensity and increase as the laser intensity increases. However, an observed "peak" in the X-ray intensity near 4.75 keV occurs at an irradiance of 4.0 × 1015 W/cm2. For the employed experimental conditions, it was confirmed that the laser intensity could play a significant role in the development of an efficient multi-keV X-ray source. The experimental results for titanium indicate that the production of a large (˜350 μm in diameter) intense backlighter source of multi-keV X-rays is feasible at the SGII facility.

Long-term Modulation of Cosmic Ray Intensity in relation to Sunspot ...

Indian Academy of Sciences (India)

it should be more closely connected with cosmic ray modulation than with other solar characteristics (sunspot numbers or coronal emission intensity). The intensity of galactic cosmic rays varies inversely with sunspot numbers, having their maximum intensity at the minimum of the 11-year sunspot cycle (Forbush 1954, 1958) ...

Free-air ionization intensity in the lower atmosphere due to cosmic-ray

International Nuclear Information System (INIS)

Urabe, Itsumasa; Katsurayama, Kousuke

1979-01-01

Being able to be determined by subtracting the gamma-ray ionization intensity from that obtained with ionization chamber, cosmic-ray ionization intensity in free air was estimated by using with 15l air-filled ionization chamber and 3''diameter spherical NaI(Tl) scintillation spectrometer. Optimum applied voltage to 15l air-filled ionization chamber was determined in accordance with Scott and Greening's formula to obtain the ionization intensity caused by gamma-rays and cosmic-rays. Pulse-height distribution of cosmic-rays created in 3''diameter spherical NaI(Tl) scintillation spectrometer was investigated for the precise determination of gamma-ray ionization intensity. Field measurements were carried out by using with these two instruments at about 1.5 meter above the ground in the several locations around Research Reactor Institute of Kyoto University. Cosmic-ray ionization intensity in free air was estimated from the results obtained with air-filled ionization chamber and was 3.33 +- 0.15 μR/hr equivalent in natural environment near Research Reactor Institute of Kyoto University. (author)

X-ray investigations in intensive care units

Energy Technology Data Exchange (ETDEWEB)

Pokieser, H.

1981-10-01

From special care following surgery and from arteficial respiration of polio patients the modern and very special intensive medical care has developed. At the same time the provisional bedside radiology was improved to one branch of clinical radiology with special organisation and methods of investigation. Importance and urgency of radiological information are requiring close cooperation of all medical branches. Functions of these different groups have to be defined. The movable X-ray apparatus of 20 kV output is necessary for every intensive care unit. Hard beam technique for lung X-rays, scattered radiation grids and adequate positioning of the patient are important to get the same high quality pictures than from the radiological department.

X-ray investigations in intensive care units

International Nuclear Information System (INIS)

Pokieser, H.

1981-01-01

From special care following surgery and from arteficial respiration of polio patients the modern and very special intensive medical care has developed. At the same time the provisional bedside radiology was improved to one branch of clinical radiology with special organisation and methods of investigation. Importance and urgency of radiological information are requiring close cooperation of all medical branches. Functions of these different groups have to be defined. The movable X-ray apparatus of 20 kV output is necessary for every intensive care unit. Hard beam technique for lung X-rays, scattered radiation grids and adequate positioning of the patient are important to get the same high quality pictures than from the radiological department. (orig.) [de

A Numerical Study of Forbush Decreases with a 3D Cosmic-Ray Modulation Model Based on an SDE Approach

Energy Technology Data Exchange (ETDEWEB)

Luo, Xi; Feng, Xueshang [SIGMA Weather Group, State Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing 100190 (China); Potgieter, Marius S. [Centre for Space Research, North-West University, Potchefstroom 2520 (South Africa); Zhang, Ming [Department of Physics and Space Sciences, Florida Institute of Technology, 150 West University Boulevard, Melbourne, FL 32901 (United States)

2017-04-10

Based on the reduced diffusion mechanism for producing Forbush decreases (Fds) in the heliosphere, we constructed a three-dimensional (3D) diffusion barrier, and by incorporating it into a stochastic differential equation (SDE) based time-dependent, cosmic-ray transport model, a 3D numerical model for simulating Fds is built and applied to a period of relatively quiet solar activity. This SDE model generally corroborates previous Fd simulations concerning the effects of the solar magnetic polarity, the tilt angle of the heliospheric current sheet (HCS), and cosmic-ray particle energy. Because the modulation processes in this 3D model are multi-directional, the barrier’s geometrical features affect the intensity profiles of Fds differently. We find that both the latitudinal and longitudinal extent of the barrier have relatively fewer effects on these profiles than its radial extent and the level of decreased diffusion inside the disturbance. We find, with the 3D approach, that the HCS rotational motion causes the relative location from the observation point to the HCS to vary, so that a periodic pattern appears in the cosmic-ray intensity at the observing location. Correspondingly, the magnitude and recovery time of an Fd change, and the recovering intensity profile contains oscillation as well. Investigating the Fd magnitude variation with heliocentric radial distance, we find that the magnitude decreases overall and, additionally, that the Fd magnitude exhibits an oscillating pattern as the radial distance increases, which coincides well with the wavy profile of the HCS under quiet solar modulation conditions.

X-ray absorption intensity at high-energy region

International Nuclear Information System (INIS)

Fujikawa, Takashi; Kaneko, Katsumi

2012-01-01

We theoretically discuss X-ray absorption intensity in high-energy region far from the deepest core threshold to explain the morphology-dependent mass attenuation coefficient of some carbon systems, carbon nanotubes (CNTs), highly oriented pyrolytic graphite (HOPG) and fullerenes (C 60 ). The present theoretical approach is based on the many-body X-ray absorption theory including the intrinsic losses (shake-up losses). In the high-energy region the absorption coefficient has correction term dependent on the solid state effects given in terms of the polarization part of the screened Coulomb interaction W p . We also discuss the tail of the valence band X-ray absorption intensity. In the carbon systems C 2s contribution has some influence on the attenuation coefficient even in the high energy region at 20 keV.

Overview of high intensity x-ray and gamma-ray sources

International Nuclear Information System (INIS)

Prestwich, K.R.; Lee, J.R.; Ramirez, J.J.; Sanford, T.W.L.; Agee, F.J.; Frazier, G.B.; Miller, A.R.

1987-01-01

The requirements for intense x-ray and gamma-ray sources to simulate the radiation effects from nuclear weapons has led to the development of several types of terawatt-pulsed power systems. One example of a major gamma-ray source is Aurora, a 10-MV, 1.6-MA, 120-ns four-module, electron-beam generator. Recent requirements to improve the dose rate has led to the Aurora upgrade program and to the development of the 20-MV, 800-kA, 40-ns Hermes-III electron-beam accelerator. The Aurora program includes improvements to the pulsed power system and research on techniques to improve the pulse shape of the electron beam. Hermes III will feature twenty 1-MV, 800-kA induction accelerator cavities supplying energy to a magnetically insulated transmission line adder. Hermes III will become operational in 1988. Intense x-ray sources consist of pulsed power systems that operate with 1-MV to 2-MV output voltages and up to 25-TW output powers. These high powers are achieved with either low impedance electron-beam generators or multimodular pulsed power systems. The low-impedance generators have high voltage Marx generators that store the energy and then sequentially transfer this energy to pulse-forming transmission lines with lower and lower impedance until the high currents are reached. In the multimode machines, each module produces 0.7-TW to 4-TW output pulses, and all of the modules are connected together to supply energy to a single diode

Gamma-ray line intensities for depleted uranium

International Nuclear Information System (INIS)

Moss, C.E.

1985-01-01

Measurements of the gamma-ray line intensities from depleted uranium allowed us to determine which of two conflicting previous experiments was correct. For the 1001-keV line we obtain a branching ratio of 0.834 +- 0.007, in good agreement with one of the previous experiments. A table compares our intensities for several lines with those obtained in previous experiments. 5 refs., 2 figs., 1 tab

Intensity-Modulated Advanced X-ray Source (IMAXS) for Homeland Security Applications

International Nuclear Information System (INIS)

Langeveld, Willem G. J.; Johnson, William A.; Owen, Roger D.; Schonberg, Russell G.

2009-01-01

X-ray cargo inspection systems for the detection and verification of threats and contraband require high x-ray energy and high x-ray intensity to penetrate dense cargo. On the other hand, low intensity is desirable to minimize the radiation footprint. A collaboration between HESCO/PTSE Inc., Schonberg Research Corporation and Rapiscan Laboratories, Inc. has been formed in order to design and build an Intensity-Modulated Advanced X-ray Source (IMAXS). Such a source would allow cargo inspection systems to achieve up to two inches greater imaging penetration capability, while retaining the same average radiation footprint as present fixed-intensity sources. Alternatively, the same penetration capability can be obtained as with conventional sources with a reduction of the average radiation footprint by about a factor of three. The key idea is to change the intensity of the source for each x-ray pulse based on the signal strengths in the inspection system detector array during the previous pulse. In this paper we describe methods to accomplish pulse-to-pulse intensity modulation in both S-band (2998 MHz) and X-band (9303 MHz) linac sources, with diode or triode (gridded) electron guns. The feasibility of these methods has been demonstrated. Additionally, we describe a study of a shielding design that would allow a 6 MV X-band source to be used in mobile applications.

Intensity of diffracted X-rays from biomolecules with radiation damage caused by strong X-ray pulses

International Nuclear Information System (INIS)

Kai, Takeshi; Tokuhisa, Atsushi; Moribayashi, Kengo; Fukuda, Yuji; Kono, Hidetoshi; Go, Nobuhiro

2014-01-01

In order to realize the coherent X-ray diffractive imaging of single biomolecules, the diffraction intensities, per effective pixel of a single biomolecule with radiation damage, caused by irradiation using a strong coherent X-ray pulse, were examined. A parameter survey was carried out for various experimental conditions, using a developed simulation program that considers the effect of electric field ionization, which was slightly reported on in previous studies. The two simple relationships among the parameters were identified as follows: (1) the diffraction intensity of a biomolecule slightly increases with the incident X-ray energy; and that (2) the diffraction intensity is approximately proportional to the target radius, when the radius is longer than 400 Å, since the upper limit of the incident intensity for damage to the biomolecules marginally changes with respect to the target radius. (author)

Cosmic ray decreases affect atmospheric aerosols and clouds

DEFF Research Database (Denmark)

Svensmark, Henrik; Bondo, Torsten; Svensmark, J.

2009-01-01

Close passages of coronal mass ejections from the sun are signaled at the Earth's surface by Forbush decreases in cosmic ray counts. We find that low clouds contain less liquid water following Forbush decreases, and for the most influential events the liquid water in the oceanic atmosphere can...... diminish by as much as 7%. Cloud water content as gauged by the Special Sensor Microwave/Imager (SSM/I) reaches a minimum ≈7 days after the Forbush minimum in cosmic rays, and so does the fraction of low clouds seen by the Moderate Resolution Imaging Spectroradiometer (MODIS) and in the International...

Reconstructing the long-term cosmic ray intensity: linear relations do not work

Directory of Open Access Journals (Sweden)

K. Mursula

2003-04-01

Full Text Available It was recently suggested (Lockwood, 2001 that the cosmic ray intensity in the neutron monitor energy range is linearly related to the coronal source flux, and can be reconstructed for the last 130 years using the long-term coronal flux estimated earlier. Moreover, Lockwood (2001 reconstructed the coronal flux for the last 500 years using a similar linear relation between the flux and the concentration of cosmogenic 10 Be isotopes in polar ice. Here we show that the applied linear relations are oversimplified and lead to unphysical results on long time scales. In particular, the cosmic ray intensity reconstructed by Lockwood (2001 for the last 130 years has a steep trend which is considerably larger than the trend estimated from observations during the last 65 years. Accordingly, the reconstructed cosmic ray intensity reaches or even exceeds the local interstellar cosmic ray flux around 1900. We argue that these unphysical results obtained when using linear relations are due to the oversimplified approach which does not take into account the complex and essentially nonlinear nature of long-term cosmic ray modulation in the heliosphere. We also compare the long-term cosmic ray intensity based on a linear treatment with the reconstruction based on a recent physical model which predicts a considerably lower cosmic ray intensity around 1900.Key words. Interplanetary physics (cosmic rays; heliopause and solar wind termination – Geomagnetism and paleomagnetism (time variations, secular and long-term

Femtosecond response of polyatomic molecules to ultra-intense hard X-rays.

Science.gov (United States)

Rudenko, A; Inhester, L; Hanasaki, K; Li, X; Robatjazi, S J; Erk, B; Boll, R; Toyota, K; Hao, Y; Vendrell, O; Bomme, C; Savelyev, E; Rudek, B; Foucar, L; Southworth, S H; Lehmann, C S; Kraessig, B; Marchenko, T; Simon, M; Ueda, K; Ferguson, K R; Bucher, M; Gorkhover, T; Carron, S; Alonso-Mori, R; Koglin, J E; Correa, J; Williams, G J; Boutet, S; Young, L; Bostedt, C; Son, S-K; Santra, R; Rolles, D

2017-06-01

X-ray free-electron lasers enable the investigation of the structure and dynamics of diverse systems, including atoms, molecules, nanocrystals and single bioparticles, under extreme conditions. Many imaging applications that target biological systems and complex materials use hard X-ray pulses with extremely high peak intensities (exceeding 10 20 watts per square centimetre). However, fundamental investigations have focused mainly on the individual response of atoms and small molecules using soft X-rays with much lower intensities. Studies with intense X-ray pulses have shown that irradiated atoms reach a very high degree of ionization, owing to multiphoton absorption, which in a heteronuclear molecular system occurs predominantly locally on a heavy atom (provided that the absorption cross-section of the heavy atom is considerably larger than those of its neighbours) and is followed by efficient redistribution of the induced charge. In serial femtosecond crystallography of biological objects-an application of X-ray free-electron lasers that greatly enhances our ability to determine protein structure-the ionization of heavy atoms increases the local radiation damage that is seen in the diffraction patterns of these objects and has been suggested as a way of phasing the diffraction data. On the basis of experiments using either soft or less-intense hard X-rays, it is thought that the induced charge and associated radiation damage of atoms in polyatomic molecules can be inferred from the charge that is induced in an isolated atom under otherwise comparable irradiation conditions. Here we show that the femtosecond response of small polyatomic molecules that contain one heavy atom to ultra-intense (with intensities approaching 10 20 watts per square centimetre), hard (with photon energies of 8.3 kiloelectronvolts) X-ray pulses is qualitatively different: our experimental and modelling results establish that, under these conditions, the ionization of a molecule is

Correlation between ionospheric potential and the intensity of cosmic rays

International Nuclear Information System (INIS)

Meyerott, R.E.; Reagan, J.B.; Evans, J.E.

1983-01-01

Ionospheric potential variations with a period of about 10 yr have been observed in the data that have been acquired to date. Previous studies have shown that these variations appear to be correlated inversely with sunspot number and with solar wind velocity, and directly with cosmic ray intensity. Since the cosmic ray intensity is inversely correlated with sunspot number and solar wind velocity, these correlations all suggest that the long period variations are of solar origin. In this report it is shown that, over the limited period for which ionospheric potential measurements exist, the long period variations are better correlated with the aerosol burden injected into the stratosphere by large volcanic eruptions than with the intensity of cosmic rays. This result indicates that the long period variations in ionospheric potential are of terrestrial rather than solar origin. 20 references

Simulation of intense laser-dense matter interactions. X-ray production and laser absorption

Energy Technology Data Exchange (ETDEWEB)

Ueshima, Yutaka; Kishimoto, Yasuaki; Sasaki, Akira [Japan Atomic Energy Research Inst., Neyagawa, Osaka (Japan). Kansai Research Establishment; Sentoku, Yasuhiko; Tajima, Toshiki

1998-03-01

The development of short-pulse ultra high intensity lasers will enable us to generate short-pulse intense soft and hard X-rays. Acceleration of an electron in laser field generates intense illuminated located radiation, Larmor radiation, around KeV at 10{sup 18} W/cm{sup 2} with 100 TW and 1 {mu}m wave length laser. The Coulomb interaction between rest ions and relativistic electron generates broad energy radiation, bremsstrahlung emission, over MeV at 10{sup 18} W/cm{sup 2} with the same condition. These intense radiations come in short pulses of the same order as that of the irradiated laser. The generated intense X-rays, Larmor and bremsstrahlung radiation, can be applied to sources of short pulse X-ray, excitation source of inner-shell X-ray laser, position production and nuclear excitation, etc. (author)

Long-term variations of cosmic ray intensity

International Nuclear Information System (INIS)

Dergachev, V.A.; Kocharov, G.E.; Ostryakov, V.M.

1982-01-01

At the present time we know only one possibility to reconstruct the Cosmic Ray intensity in the past. This possibility is connected with the measurements of radiocarbon abundance in the dendrochronologically dated wood samples. As the experiments carried out with the help of spacecrafts, balloons and ground apparatus show the Galactic Cosmic Ray flux essentially varies on a short time scales. The variations are caused by different astrophysical and geophysical phenomena. 14 C isotope allows us to investigate these reasons on a more long time interval in comparison with direct observational possibilities

Linear luminescence for thin plastic scintillator under intense soft X-ray irradiation

International Nuclear Information System (INIS)

Ning Jiamin; Jiang Shilun; Xu Rongkun; Guo Cun

2006-01-01

The basic principle of soft X-ray power meter is introduced in the paper and the experimental process and the result of thin plastic scintillator linear luminescence under intense soft X-ray irradiation are described. A range of flux density of energy for thin plastic scintillator linear luminescence under intense soft X-ray irradiation is included. The upper limit of the flux density is 1.47 x 10 5 W/cm 2 . (authors)

Irradiation of intense characteristic x-rays from weakly ionized linear molybdenum plasma

International Nuclear Information System (INIS)

Sato, Eiichi; Hayasi, Yasuomi

2003-01-01

In the plasma flash x-ray generator, a high-voltage main condenser of approximately 200 nF is charged up to 55 kV by a power supply, and electric charges in the condenser are discharged to an x-ray tube after triggering the cathode electrode. The flash x-rays are then produced. The x-ray tube is a demountable triode that is connected to a turbo molecular pump with a pressure of approximately 1 mPa. As electron flows from the cathode electrode are roughly converged to a rod molybdenum target of 2.0 mm in diameter by the electric field in the x-ray tube, weakly ionized linear plasma, which consists of molybdenum ions and electrons, forms by target evaporation. At a charging voltage of 55 kV, the maximum tube voltage was almost equal to the charging voltage of the main condenser, and the peak current was about 20 kA. When the charging voltage was increased, the linear plasma formed, and the K-series characteristic x-ray intensities increased. The K lines were quite sharp and intense, and hardly any bremsstrahlung rays were detected. The x-ray pulse widths were approximately 700 ns, and the time-integrated x-ray intensity had a value of approximately 35 μC/kg at 1.0 m from the x-ray source with a charging voltage of 50 kV. (author)

Two electron response to an intense x-ray free electron laser pulse

International Nuclear Information System (INIS)

Moore, L R; Parker, J S; Meharg, K J; Armstrong, G S J; Taylor, K T

2009-01-01

New x-ray free electron lasers (FELs) promise an ultra-fast ultra-intense regime in which new physical phenomena, such as double core hole formation in at atom, should become directly observable. Ahead of x-ray FEL experiments, an initial key task is to theoretically explore such fundamental laser-atom interactions and processes. To study the response of a two-electron positive ion to an intense x-ray FEL pulse, our theoretical approach is a direct numerical integration, incorporating non-dipole Hamiltonian terms, of the full six-dimensional time-dependent Schroedinger equation. We present probabilities of double K-shell ionization in the two-electron positive ions Ne 8+ and Ar 16+ exposed to x-ray FEL pulses with frequencies in the range 50 au to 300 au and intensities in the range 10 17 to 10 22 W/cm 2 .

GAMUT: A computer code for γ-ray energy and intensity analysis

International Nuclear Information System (INIS)

Firestone, R.B.

1991-05-01

GAMUT is a computer code to analyze γ-ray energies and intensities. It does a linear least-squares fit of measured γ-ray energies from one or more experiments to the level scheme. GAMUT also performs a non-linear least-squares analysis of branching intensities. For both energy and intensity data, a statistical Chi-square analysis is performed with an iterative uncertainty adjustment. The uncertainties of outlying measured values and sets of measurements with x 2 /f>1 are increased, and the calculation is repeated until the uncertainties are consistent with the fitted values. GAMUT accepts input from standard or special-format ENSDF data sets. The special-format ENSDF data sets were designed to permit analysis of more than one set of measurements associated with a single ENSDF data set. GAMUT prepares a standard ENSDF format output data set containing the adjusted values. If more than one input ENSDF data set is provided, GAMUT creates an ADOPTED LEVELS, GAMMAS data set containing the adjusted level and γ-ray energies and branching intensities from each level normalized to 100 for the strongest γ-ray. GAMUT also provides a summary of the results and an extensive log of the iterative analysis. GAMUT is interactive prompting the user for input and output file names and for default calculation options. This version of GAMUT has adjustable dimensions so that any maximum number of data sets, levels, and γ-rays can be established at the time of implementation. 6 refs

Intensities of incident and transmitted ultraviolet-a rays through gafchromic films

Directory of Open Access Journals (Sweden)

Toshizo Katsuda

2017-01-01

Full Text Available Gafchromic films have been applied to X-ray dosimetry in diagnostic radiology. To correct nonuniformity errors in Gafchromic films, X-rays in the double-exposure technique can be replaced with ultraviolet (UV-A rays. Intensities of the incident and transmitted UV-A rays were measured. However, it is unclear whether the chemical color change of Gafchromic films affects the UV-A transmission intensity. Gafchromic EBT3 films were suitable to be used in this study because non-UV protection layers are present on both sides of the film. The film is placed between UV-A ray light-emitting diodes and a probe of a UV meter. Gafchromic EBT3 films were irradiated by UV-A rays for up to 60 min. Data for analysis were obtained in the subsequent 60 min. Images from before and after UV-A irradiation were subtracted. When using 375 nm UV-A, the mean ± standard deviation (SD of the pixel values in the subtracted image was remarkably high (11,194.15 ± 586.63. However, the UV-A transmissivity remained constant throughout the 60 min irradiation period. The mean ± SD UV-A transmission intensity was 184.48 ± 0.50 μm/cm2. Our findings demonstrate that color density changes in Gafchromic EBT3 films do not affect their UV-A transmission. Therefore, Gafchromic films were irradiated by UV-A rays as a preexposure.

Uniformity transition for ray intensities in random media

Science.gov (United States)

Pradas, Marc; Pumir, Alain; Wilkinson, Michael

2018-04-01

This paper analyses a model for the intensity of distribution for rays propagating without absorption in a random medium. The random medium is modelled as a dynamical map. After N iterations, the intensity is modelled as a sum S of {{\\mathcal N}} contributions from different trajectories, each of which is a product of N independent identically distributed random variables x k , representing successive focussing or de-focussing events. The number of ray trajectories reaching a given point is assumed to proliferate exponentially: {{\\mathcal N}}=ΛN , for some Λ>1 . We investigate the probability distribution of S. We find a phase transition as parameters of the model are varied. There is a phase where the fluctuations of S are suppressed as N\\to ∞ , and a phase where the S has large fluctuations, for which we provide a large deviation analysis.

Two electron response to an intense x-ray free electron laser pulse

Energy Technology Data Exchange (ETDEWEB)

Moore, L R; Parker, J S; Meharg, K J; Armstrong, G S J; Taylor, K T, E-mail: l.moore@qub.ac.u [DAMTP, David Bates Building, Queen' s University Belfast, Belfast, BT7 1NN (United Kingdom)

2009-11-01

New x-ray free electron lasers (FELs) promise an ultra-fast ultra-intense regime in which new physical phenomena, such as double core hole formation in at atom, should become directly observable. Ahead of x-ray FEL experiments, an initial key task is to theoretically explore such fundamental laser-atom interactions and processes. To study the response of a two-electron positive ion to an intense x-ray FEL pulse, our theoretical approach is a direct numerical integration, incorporating non-dipole Hamiltonian terms, of the full six-dimensional time-dependent Schroedinger equation. We present probabilities of double K-shell ionization in the two-electron positive ions Ne{sup 8+} and Ar{sup 16+} exposed to x-ray FEL pulses with frequencies in the range 50 au to 300 au and intensities in the range 10{sup 17} to 10{sup 22} W/cm{sup 2}.

The high intensity {gamma}-ray source (HI{gamma}S) and recent results

Energy Technology Data Exchange (ETDEWEB)

Tonchev, A.P. [Duke University and TUNL, Triangle University Nuclear Laboratory, P.O. Box 90308, Durham, NC 27708 0308 (United States)]. E-mail: tonchev@tunl.duke.edu; Boswell, M. [University of North Carolina at Chapel Hill and TUNL, Chapel Hill, NC 27599 (United States); Howell, C.R. [Duke University and TUNL, Triangle University Nuclear Laboratory, P.O. Box 90308, Durham, NC 27708 0308 (United States); Karwowski, H.J. [University of North Carolina at Chapel Hill and TUNL, Chapel Hill, NC 27599 (United States); Kelley, J.H. [North Carolina State University and TUNL, Raleigh, NC 27695 (United States); Tornow, W. [Duke University and TUNL, Triangle University Nuclear Laboratory, P.O. Box 90308, Durham, NC 27708 0308 (United States); Wu, Y.K. [Duke University and Duke Free Electron Laser Laboratory, Durham, NC 27708-0319 (United States)

2005-12-15

The high intensity {gamma}-ray source (HI{gamma}S) utilizes intra-cavity backscattering of free electron laser photons from the Duke electron storage ring to produce a unique monoenergetic beam of high-flux {gamma}-rays with high polarization and selectable energy resolution. At present, {gamma}-ray beams with energies from 2 to 58 MeV are available with intensities as high as 10{sup 5}-5 x 10{sup 6} {gamma}/s, energy spreads of 3% or better, and nearly 100% linear polarization. The quality and intensity of the {gamma}-ray beams at HI{gamma}S are responsible for the unprecedented performance of this facility in a broad range of research programs in nuclear structure, nuclear astrophysics and nuclear applications. Recent results from excitation of isomeric states in ({gamma}, n) reactions and parity assignments of dipole states determined via the ({gamma}, {gamma}') reaction are presented.

On the continuous measurement of the cosmic-ray intensity, 2

International Nuclear Information System (INIS)

Ishida, Yoshio; Kanno, Tsunekichi

1974-01-01

Since November 1971, the cosmic ray neutron intensity has been measured continuously with 3NM-64 neutron monitor at Fukushima University (140 0 29'E geographic longitude, 37 0 45'N geographic latitude, 27.6 0 N geomagnetic latitude and 10.55 GV cut-off rigidity). After the neutron monitor had been operated during the period of fourteen months at the ground floor of 3-storied ferro-reinforced concrete building, it was removed to the prefabricated house near the old position of the monitor at January 1973. As a result of the removement of the monitor, the expected values for the counting rate and barometric coefficient of our neutron monitor were obtained, 7.5x10 4 cph and -0.64% mb respectively. The monitor was moved out into a new place, the statistical accuracy of counting rate is altered from 0.44% (hourly counting rate) to 0.36%. It can be considered that there is no effect of concrete building near the monitor, for reason that the zenith angle is opened more than 60 0 over the monitor. The difference between the new and the old measurement - measurement environments, intensities, barometric coefficient and others - were discussed. The continuous measurement of the cosmic ray neutron intensity at Fukushima will be kept on beaten track, and the obtained data of the cosmic ray neutron intensity (uncorrected, corrected intensity and barometric pressure) will be sent to WDC-C2 in form of monthly tables. (author)

Cosmic ray intensity distribution in the vertical direction to solar equator plane

International Nuclear Information System (INIS)

Nosaka, Toru; Mori, Satoru; Sagisaka, Shuji.

1983-01-01

The data of the annual variation of cosmic ray intensity measured by neutron detectors were used to study the distribution of cosmic ray intensity vertical to the solar equator plane and its long term variation. The data used were obtained at Deep River, Kiel, Kerguelen Island, McMurdo, Ottawa, and Mt. Washington. All data showed annual variation. The patterns and degree of variation obtained in northern and southern hemisphere were similar. The summation dial representation of the annual variation and semi-annual variation of cosmic ray was obtained. The inversion of annual variation in 1958 - 1959 and 1968 - 1969 corresponded to the inversion of polarity of solar pole magnetic field. The semi-annual variation showed a complex behavior. The helio-latitudial distribution of cosmic ray intensity was obtained. The asymmetric distribution in relation to the solar equator was observed in the annual variation. The northward gradient of density in 1955 - 1958 and southward gradient in 1959 - 1968 were seen. (Kato, T.)

Origin-independent calculation of quadrupole intensities in X-ray spectroscopy

International Nuclear Information System (INIS)

Bernadotte, Stephan; Atkins, Andrew J.; Jacob, Christoph R.

2012-01-01

For electronic excitations in the ultraviolet and visible range of the electromagnetic spectrum, the intensities are usually calculated within the dipole approximation, which assumes that the oscillating electric field is constant over the length scale of the transition. For the short wavelengths used in hard X-ray spectroscopy, the dipole approximation may not be adequate. In particular, for metal K-edge X-ray absorption spectroscopy (XAS), it becomes necessary to include higher-order contributions. In quantum-chemical approaches to X-ray spectroscopy, these so-called quadrupole intensities have so far been calculated by including contributions depending on the square of the electric-quadrupole and magnetic-dipole transition moments. However, the resulting quadrupole intensities depend on the choice of the origin of the coordinate system. Here, we show that for obtaining an origin-independent theory, one has to include all contributions that are of the same order in the wave vector consistently. This leads to two additional contributions depending on products of the electric-dipole and electric-octupole and of the electric-dipole and magnetic-quadrupole transition moments, respectively. We have implemented such an origin-independent calculation of quadrupole intensities in XAS within time-dependent density-functional theory, and demonstrate its usefulness for the calculation of metal and ligand K-edge XAS spectra of transition metal complexes.

Behaviour of large-area avalanche photodiodes under intense magnetic fields for VUV- visible- and X-ray photon detection

International Nuclear Information System (INIS)

Fernandes, L.M.P.; Antognini, A.; Boucher, M.; Conde, C.A.N.; Huot, O.; Knowles, P.; Kottmann, F.; Ludhova, L.; Mulhauser, F.; Pohl, R.; Schaller, L.A.; Santos, J.M.F. dos; Taqqu, D.; Veloso, J.F.C.A.

2003-01-01

The behaviour of large-area avalanche photodiodes for X-rays, visible and vacuum-ultra-violet (VUV) light detection in magnetic fields up to 5 T is described. For X-rays and visible light detection, the photodiode pulse amplitude and energy resolution were unaffected from 0 to 5 T, demonstrating the insensitivity of this type of detector to strong magnetic fields. For VUV light detection, however, the photodiode relative pulse amplitude decreases with increasing magnetic field intensity reaching a reduction of about 24% at 5 T, and the energy resolution degrades noticeably with increasing magnetic field

A calculation model for primary intensity distributions from cylindrically symmetric x-ray lenses

International Nuclear Information System (INIS)

Hristov, Dimitre; Maltz, Jonathan

2008-01-01

A calculation model for the quantitative prediction of primary intensity fluence distributions obtained by the Bragg diffraction focusing of kilovoltage radiation by cylindrical x-ray lenses is presented. The mathematical formalism describes primary intensity distributions from cylindrically-symmetric x-ray lenses, with a planar isotropic radiation source located in a plane perpendicular to the lens axis. The presence of attenuating medium inserted between the lens and the lens focus is accounted for by energy-dependent attenuation. The influence of radiation scattered within the media is ignored. Intensity patterns are modeled under the assumption that photons that are not interacting with the lens are blocked out at any point of interest. The main characteristics of the proposed calculation procedure are that (i) the application of vector formalism allows universal treatment of all cylindrical lenses without the need of explicit geometric constructs; (ii) intensity distributions resulting from x-ray diffraction are described by a 3D generalization of the mosaic spread concept; (iii) the calculation model can be immediately coupled to x-ray diffraction simulation packages such as XOP and Shadow. Numerical simulations based on this model are to facilitate the design of focused orthovoltage treatment (FOT) systems employing cylindrical x-ray lenses, by providing insight about the influence of the x-ray source and lens parameters on quantities of dosimetric interest to radiation therapy

Ultrafast absorption of intense x rays by nitrogen molecules

Energy Technology Data Exchange (ETDEWEB)

Buth, Christian [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany); PULSE Institute for Ultrafast Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803 (United States); Argonne National Laboratory, Argonne, Illinois 60439 (United States); Liu Jicai [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany); Department of Mathematics and Physics, North China Electric Power University, 102206 Beijing (China); Chen, Mau Hsiung [Physics Division, Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Cryan, James P. [PULSE Institute for Ultrafast Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Department of Physics, Stanford University, Stanford, California 94305 (United States); Fang Li; Hoener, Matthias; Berrah, Nora [Department of Physics, Western Michigan University, Kalamazoo, Michigan 49008 (United States); Glownia, James M. [PULSE Institute for Ultrafast Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Department of Applied Physics, Stanford University, Stanford, California 94305 (United States); Coffee, Ryan N. [PULSE Institute for Ultrafast Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States)

2012-06-07

We devise a theoretical description for the response of nitrogen molecules (N{sub 2}) to ultrashort and intense x rays from the free electron laser Linac Coherent Light Source (LCLS). We set out from a rate-equation description for the x-ray absorption by a nitrogen atom. The equations are formulated using all one-x-ray-photon absorption cross sections and the Auger and radiative decay widths of multiply-ionized nitrogen atoms. Cross sections are obtained with a one-electron theory and decay widths are determined from ab initio computations using the Dirac-Hartree-Slater (DHS) method. We also calculate all binding and transition energies of nitrogen atoms in all charge states with the DHS method as the difference of two self-consistent field (SCF) calculations ({Delta}SCF method). To describe the interaction with N{sub 2}, a detailed investigation of intense x-ray-induced ionization and molecular fragmentation are carried out. As a figure of merit, we calculate ion yields and the average charge state measured in recent experiments at the LCLS. We use a series of phenomenological models of increasing sophistication to unravel the mechanisms of the interaction of x rays with N{sub 2}: a single atom, a symmetric-sharing model, and a fragmentation-matrix model are developed. The role of the formation and decay of single and double core holes, the metastable states of N{sub 2}{sup 2+}, and molecular fragmentation are explained.

Muonic X-ray intensities in phosphorus- and selenium modifications

International Nuclear Information System (INIS)

Kaeser, K.; Robert-Tissot, B.; Schaller, L.A.; Schellenberg, L.; Schneuwly, H.

1979-01-01

Muonic X-ray intensity measurements have been performed at SIN on allotropic modifications of phosphorus (white, red and black) and of selenium (red and black). Structure effects have been found in the intensity ratios of the K-series between amorphous and crystalline modifications of the same element. The effect in the higher series (Se) is less pronounced. On the other hand, the two crystalline phosphorus modifications (red and black) show the same intensity behavior. The root-mean-square radii 2 >sup(1/2) of phosphorus and (natural) selenium were found to be 3.187(3) fm and 4.138(1) fm respectively. (Auth.)

X-ray tomography investigation of intensive sheared Al–SiC metal matrix composites

Energy Technology Data Exchange (ETDEWEB)

De Giovanni, Mario; Warnett, Jason M.; Williams, Mark A. [WMG, University of Warwick, Coventry CV4 7AL (United Kingdom); Haribabu, Nadendla [BCAST, Brunel University London, Uxbridge UB8 3PH (United Kingdom); Srirangam, Prakash, E-mail: p.srirangam@warwick.ac.uk [WMG, University of Warwick, Coventry CV4 7AL (United Kingdom)

2015-12-15

X-ray computed tomography (XCT) was used to characterise three dimensional internal structure of Al–SiC metal matrix composites. The alloy composite was prepared by casting method with the application of intensive shearing to uniformly disperse SiC particles in the matrix. Visualisation of SiC clusters as well as porosity distribution were evaluated and compared with non-shearing samples. Results showed that the average particle size as well as agglomerate size is smaller in sheared sample compared to conventional cast samples. Further, it was observed that the volume fraction of porosity was reduced by 50% compared to conventional casting, confirming that the intensive shearing helps in deagglomeration of particle clusters and decrease in porosity of Al–SiC metal matrix composites. - Highlights: • XCT was used to visualise 3D internal structure of Al-SiC MMC. • Al-SiC MMC was prepared by casting with the application of intensive shearing. • SiC particles and porosity distribution were evaluated. • Results show shearing deagglomerates particle clusters and reduces porosity in MMC.

Estimation of signal intensity for online measurement X-ray pinhole camera

International Nuclear Information System (INIS)

Dong Jianjun; Liu Shenye; Yang Guohong; Yu Yanning

2009-01-01

The signal intensity was estimated for on-line measurement X-ray pinhole camera with CCD as measurement equipment. The X-ray signal intensity counts after the attenuation of thickness-varied Be filters and different material flat mirrors respectively were estimated using the energy spectrum of certain laser prototype and the quantum efficiency curve of PI-SX1300 CCD camera. The calculated results indicate that Be filters no thicker than 200 μm can only reduce signal intensity by one order of magnitude, and so can Au flat mirror with 3 degree incident angle, Ni, C and Si flat mirrors with 5 degree incident angle,but the signal intensity counts for both attenuation methods are beyond the saturation counts of the CCD camera. We also calculated the attenuation of signal intensity for different thickness Be filters combined with flat mirrors, indicates that the combination of Be filters with the thickness between 20 and 40 μm and Au flat mirror with 3 degree incident angle or Ni flat mirror with 5 degree incident angle is a good choice for the attenuation of signal intensity. (authors)

Effects of cosmic ray decreases on cloud microphysics

DEFF Research Database (Denmark)

Svensmark, J.; Enghoff, M. B.; Svensmark, H.

2012-01-01

Using cloud data from MODIS we investigate the response of cloud microphysics to sudden decreases in galactic cosmic radiation – Forbush decreases – and find responses in effective emissivity, cloud fraction, liquid water content, and optical thickness above the 2–3 sigma level 6–9 days after...... the minimum in atmospheric ionization and less significant responses for effective radius and cloud condensation nuclei (... of the signal of 3.1 sigma. We also see a correlation between total solar irradiance and strong Forbush decreases but a clear mechanism connecting this to cloud properties is lacking. There is no signal in the UV radiation. The responses of the parameters correlate linearly with the reduction in the cosmic ray...

Phenylephrine decreases frontal lobe oxygenation at rest but not during moderately intense exercise

DEFF Research Database (Denmark)

Brassard, Patrice; Seifert, Thomas; Wissenberg, Mads

2010-01-01

high-intensity exercise (-3%, P=not significant), where PaCO2 decreased 7% (Padministration of phenylephrine reduced ScO2 but that the increased cerebral metabolism needed for moderately intense exercise eliminated that effect....... the administration of phenylephrine during low-intensity exercise (approximately 15%), but this was attenuated (approximately 10%) during high-intensity exercise (Padministration of phenylephrine was attenuated during low-intensity exercise (-5%, P

Solar cycle variation of cosmic ray intensity along with interplanetary and solar wind plasma parameters

International Nuclear Information System (INIS)

Mishra, R.K.; Tiwari, S.; Agarwal, R.

2008-01-01

Galactic cosmic rays are modulated at their propagation in the heliosphere by the effect of the large-scale structure of the interplanetary medium. A comparison of the variations in the cosmic ray intensity data obtained by neutron monitoring stations with those in geomagnetic disturbance, solar wind velocity (V), interplanetary magnetic field (B), and their product (V , B) near the Earth for the period 1964-2004 has been presented so as to establish a possible correlation between them. We used the hourly averaged cosmic ray counts observed with the neutron monitor in Moscow. It is noteworthy that a significant negative correlation has been observed between the interplanetary magnetic field, product (V , B) and cosmic ray intensity during the solar cycles 21 and 22. The solar wind velocity has a good positive correlation with cosmic ray intensity during solar cycle 21, whereas it shows a weak correlation during cycles 20, 22 and 23. The interplanetary magnetic field shows a weak negative correlation with cosmic rays for solar cycle 20, and a good anti-correlation for solar cycles 21-23 with the cosmic ray intensity, which, in turn, shows a good positive correlation with disturbance time index (Dst) during solar cycles 21 and 22, and a weak correlation for cycles 20 and 23. (Authors)

Effects of cosmic ray decreases on cloud microphysics

DEFF Research Database (Denmark)

Svensmark, J.; Enghoff, M. B.; Svensmark, H.

2012-01-01

the minimum in atmospheric ionization and less significant responses for effective radius and cloud condensation nuclei (total significance...... of the signal of 3.1 sigma. We also see a correlation between total solar irradiance and strong Forbush decreases but a clear mechanism connecting this to cloud properties is lacking. There is no signal in the UV radiation. The responses of the parameters correlate linearly with the reduction in the cosmic ray......Using cloud data from MODIS we investigate the response of cloud microphysics to sudden decreases in galactic cosmic radiation – Forbush decreases – and find responses in effective emissivity, cloud fraction, liquid water content, and optical thickness above the 2–3 sigma level 6–9 days after...

Decreasing Asian summer monsoon intensity after 1860 AD in the global warming epoch

Energy Technology Data Exchange (ETDEWEB)

Xu, Hai [Institute of Earth Environment, Chinese Academy of Sciences, State Key Laboratory of Loess and Quaternary Geology, Xi' an, Shaanxi Province (China); Hong, Yetang; Hong, Bin [Institute of Geochemistry, Chinese Academy of Sciences, State Key Laboratory of Environmental Geochemistry, Guiyang (China)

2012-10-15

The trend of the Indian summer monsoon (ISM) intensity and its nature during the past 100 and 200 years still remain unclear. In this study we reconstructed the ISM intensity during the past 270 years from tree ring {delta}{sup 18}O at Hongyuan, eastern edge of the Tibet Plateau. The monsoon failures inferred from {delta}{sup 18}O{sub tree} {sub ring} correlate well with those recorded in ice cores, speleothem, and historical literature sources. 22.6, 59.0, and 110.9-years frequency components in the Hongyuan {delta}{sup 18}O{sub tree} {sub ring} series, which may be the responses to solar activities, synchronize well with those recorded in other ISM indices. A notable feature of the reconstructed ISM intensity is the gradually decreasing trend from about 1860 to the present, which is inversely related to the increasing temperature trend contemporaneously. Such ''decreasing ISM intensity-increasing temperature'' tendency can also be supported by ice core records and meteorological records over a wide geographic extension. The decrease in sea surface temperature gradient between tropical and north Indian Ocean, and the decrease in land-sea thermal contrast between tropical Indian Ocean and ''Indian sub-continent-western Himalaya'' are possibly responsible for the observed decreasing ISM trend. (orig.)

Towards phasing using high X-ray intensity

Directory of Open Access Journals (Sweden)

Lorenzo Galli

2015-11-01

Full Text Available X-ray free-electron lasers (XFELs show great promise for macromolecular structure determination from sub-micrometre-sized crystals, using the emerging method of serial femtosecond crystallography. The extreme brightness of the XFEL radiation can multiply ionize most, if not all, atoms in a protein, causing their scattering factors to change during the pulse, with a preferential `bleaching' of heavy atoms. This paper investigates the effects of electronic damage on experimental data collected from a Gd derivative of lysozyme microcrystals at different X-ray intensities, and the degree of ionization of Gd atoms is quantified from phased difference Fourier maps. A pattern sorting scheme is proposed to maximize the ionization contrast and the way in which the local electronic damage can be used for a new experimental phasing method is discussed.

Towards phasing using high X-ray intensity

International Nuclear Information System (INIS)

Galli, Lorenzo; Son, Sang-Kil; Barends, Thomas R. M.; White, Thomas A.; Barty, Anton; Botha, Sabine; Boutet, Sebastien; Caleman, Carl; Doak, R. Bruce; Nanao, Max H.; Nass, Karol; Shoeman, Robert L.; Timneanu, Nicusor; Santra, Robin; Schlichting, Ilme; Chapman, Henry N.

2015-01-01

X-ray free-electron lasers (XFELs) show great promise for macromolecular structure determination from sub-micrometre-sized crystals, using the emerging method of serial femtosecond crystallography. The extreme brightness of the XFEL radiation can multiply ionize most, if not all, atoms in a protein, causing their scattering factors to change during the pulse, with a preferential 'bleaching' of heavy atoms. This paper investigates the effects of electronic damage on experimental data collected from a Gd derivative of lysozyme microcrystals at different X-ray intensities, and the degree of ionization of Gd atoms is quantified from phased difference Fourier maps. In conclusion, a pattern sorting scheme is proposed to maximize the ionization contrast and the way in which the local electronic damage can be used for a new experimental phasing method is discussed

Galactic cosmic-ray intensity to a heliocentric distance of 18 AU

International Nuclear Information System (INIS)

Van Allen, J.A.

1980-01-01

An updated report is given of observations of galactic cosmic-ray intensity to heliocentric radial distance of 8.6 and 18.4 AU with Pioneer 11 and Pioneer 10, respectively. Solar activity via the magnetic structure of the interplanetary medium continues to modulate the intensity out to the greatest distance reached thus far. During the 7 year period 1972 March to 1979 March, the galactic cosmic-ray intensity E/sub p/>80 MeV as measured by detectors on Pioneers 10 and 11 exhibited aperiodic temporal variations by about a factor of 2 and on a time scale of the order of a year and quasi-persistent cyclic variations of 26 day period and amplitude a few percent. The former are attributed to overall changes in the magnetic field structure of the heliosphere, the latter to fast-slow solar wind streams in and near the ecliptic plane and not to toward-away magnetic field sectors. The apparent heliographic latitude dependence of intensity is 0( +- 1.5)% per 10 0 in the latitude range +7 0 .7 to +15. 0 8, though it is possible that radially dependent temporal variations over the large difference in the heliocentric radial distances of the two spacecraft may make this result of limited significance. For protons of energy E/sub p/>80 MeV, there is a fairly consistent heliocentric radial gradient of +2.1( +- 0.3)% per AU integral intensity until 1978 April--May, at which time a substantial disruption of the distribution of cosmic rays in the heliosphere occurred

Research on temperature measurement by X-ray transmission intensity

International Nuclear Information System (INIS)

Chen, Shuyue; Cheng, Rong

2013-01-01

The relationship between temperature and X-ray transmission intensity was researched and analyzed by inspecting material density change, which is caused by thermal expansion. A digital radiographic system was employed to obtain the images. On this basis, we deduced the temperature formula based on the average gray level of the captured images. The measured temperatures were obtained from the experiments and the errors were analyzed. We concluded that when X-rays pass through an object, the X-ray strength and the gray level of the image under high temperatures are greater than those under lower temperatures and the image gray level error has great impact on the accuracy of the measured temperature. The presented approach allowed the non-contact temperature measurement of material

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

Energy Technology Data Exchange (ETDEWEB)

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

2013-07-01

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

Galactic cosmic ray spectral index: the case of Forbush decreases of March 2012

Science.gov (United States)

Livada, M.; Mavromichalaki, H.; Plainaki, C.

2018-01-01

During the burst of solar activity in March 2012, close to the maximum of solar cycle 24, a number of X-class and M-class flares and halo CMEs with velocity up to 2684 km/s were recorded. During a relatively short period (7-21 March 2012) two Forbush decreases were registered in the ground-level neutron monitor data. In this work, after a short description of the solar and geomagnetic background of these Forbush decreases, we deduce the cosmic ray density and anisotropy variations based on the daily cosmic ray data of the neutron monitor network (http://www.nmdb.eu; http://cosray.phys.uoa.gr). Applying to our data two different coupling functions methods, the spectral index of these Forbush decreases was calculated following the technique of Wawrzynczak and Alania (Adv. Space Res. 45:622-631, 2010). We pointed out that the estimated values of the spectral index γ of these events are almost similar for both cases following the fluctuation of the Forbush decrease. The study and the calculation of the cosmic ray spectrum during such cosmic ray events are very important for Space Weather applications.

X-ray luminescence computed tomography imaging via multiple intensity weighted narrow beam irradiation

Science.gov (United States)

Feng, Bo; Gao, Feng; Zhao, Huijuan; Zhang, Limin; Li, Jiao; Zhou, Zhongxing

2018-02-01

The purpose of this work is to introduce and study a novel x-ray beam irradiation pattern for X-ray Luminescence Computed Tomography (XLCT), termed multiple intensity-weighted narrow-beam irradiation. The proposed XLCT imaging method is studied through simulations of x-ray and diffuse lights propagation. The emitted optical photons from X-ray excitable nanophosphors were collected by optical fiber bundles from the right-side surface of the phantom. The implementation of image reconstruction is based on the simulated measurements from 6 or 12 angular projections in terms of 3 or 5 x-ray beams scanning mode. The proposed XLCT imaging method is compared against the constant intensity weighted narrow-beam XLCT. From the reconstructed XLCT images, we found that the Dice similarity and quantitative ratio of targets have a certain degree of improvement. The results demonstrated that the proposed method can offer simultaneously high image quality and fast image acquisition.

High intensity line source for x-ray spectrometer calibration

International Nuclear Information System (INIS)

Thoe, R.S.

1986-06-01

A high intensity electron-impact x-ray source using a one-dimensional Pierce lens has been built for the purpose of calibrating a bent crystal x-ray spectrometer. This source focuses up to 100 mA of 20-keV electrons to a line on a liquid-cooled anode. The line (which can serve as a virtual slit for the spectrometer) measures approximately 800 μ x 2 cm. The source is portable and therefore adaptable to numerous types of spectrometer applications. One particular application, the calibration of a high resolution (r = 10 4 ) time-resolved cyrstal spectrometer, will be discussed in detail

Performance Characteristics Of An Intensity Modulated Advanced X-Ray Source (IMAXS) For Homeland Security Applications

International Nuclear Information System (INIS)

Langeveld, Willem G. J.; Brown, Craig; Condron, Cathie; Ingle, Mike; Christensen, Phil A.; Johnson, William A.; Owen, Roger D.; Hernandez, Michael; Schonberg, Russell G.; Ross, Randy

2011-01-01

X-ray cargo inspection systems for the detection and verification of threats and contraband must address stringent, competitive performance requirements. High x-ray intensity is needed to penetrate dense cargo, while low intensity is desirable to minimize the radiation footprint, i.e. the size of the controlled area, required shielding and the dose to personnel. In a collaborative effort between HESCO/PTSE Inc., XScell Corp., Stangenes Industries, Inc. and Rapiscan Laboratories, Inc., an Intensity Modulated Advanced X-ray Source (IMAXS) was designed and produced. Cargo inspection systems utilizing such a source have been projected to achieve up to 2 inches steel-equivalent greater penetration capability, while on average producing the same or smaller radiation footprint as present fixed-intensity sources. Alternatively, the design can be used to obtain the same penetration capability as with conventional sources, but reducing the radiation footprint by about a factor of three. The key idea is to anticipate the needed intensity for each x-ray pulse by evaluating signal strength in the cargo inspection system detector array for the previous pulse. The IMAXS is therefore capable of changing intensity from one pulse to the next by an electronic signal provided by electronics inside the cargo inspection system detector array, which determine the required source intensity for the next pulse. We report on the completion of a 9 MV S-band (2998 MHz) IMAXS source and comment on its performance.

Measurement of relative intensities of L-shell x-rays in some high-Z elements

Energy Technology Data Exchange (ETDEWEB)

Kumar, S; Mittal, R; Allawadhi, K L; Sood, B S [Punjabi Univ., Patiala (India). Nuclear Science Labs.

1982-10-14

The L-shell x-ray relative intensities I(Lsub(..cap alpha..))/I(Lsub(l)),I(Lsub(..cap alpha..))/I(Lsub(..beta..)) and I(Lsub(..cap alpha..))/I(Lsub(..gamma..)) for U, Th, Pb and ratios I(Lsub(..cap alpha..+l))/I(Lsub(..beta..)) and I(Lsub(..cap alpha..+l))/I(Lsub(..gamma..)) for W have been measured. The L-shell electrons are excited by 59.57 keV gamma rays from /sup 241/Am and the fluorescent L-shell x-ray intensities are measured with a Si(Li) detector. The experimental results are found to agree well with theory.

Variations of interplanetary parameters and cosmic-ray intensities

International Nuclear Information System (INIS)

Geranios, A.

1980-01-01

Observations of cosmic ray intensity depressions by earth bound neutron monitors and measurements of interplanetary parameter's variations aboard geocentric satellites in the period January 1972-July 1974 are analysed and grouped according to their correlation among them. From this analysis of about 30 cases it came out that the majority of the depressions correlates with the average propagation speed of interplanetary shocks as well as with the amplitude of the interplanetary magnetic field after the eruption of a solar flare. About one fourth of the events correlates with corotating fast solar wind streams. As the recovery time of the shock-related depressions depends strongly on the heliographic longitude of the causitive solar flare, it seems that the cosmic ray modulation region has a corotative-like feature. (Auth.)

Improving accuracy and capabilities of X-ray fluorescence method using intensity ratios

Energy Technology Data Exchange (ETDEWEB)

Garmay, Andrey V., E-mail: andrew-garmay@yandex.ru; Oskolok, Kirill V.

2017-04-15

An X-ray fluorescence analysis algorithm is proposed which is based on a use of ratios of X-ray fluorescence lines intensities. Such an analytical signal is more stable and leads to improved accuracy. Novel calibration equations are proposed which are suitable for analysis in a broad range of matrix compositions. To apply the algorithm to analysis of samples containing significant amount of undetectable elements a use of a dependence of a Rayleigh-to-Compton intensity ratio on a total content of these elements is suggested. The technique's validity is shown by analysis of standard steel samples, model metal oxides mixture and iron ore samples.

Intensities and strong interaction attenuation of kaonic x-rays

CERN Document Server

Backenstoss, Gerhard; Koch, H; Povel, H P; Schwitter, A; Tauscher, Ludwig

1974-01-01

Relative intensities of numerous kaonic X-ray transitions have been measured for the elements C, P, S, and Cl, from which level widths due to the strong K-nucleus absorption have been determined. From these and earlier published data, optical potential parameters have been derived and possible consequences on the nuclear matter distribution are discussed. (10 refs).

Forbush decreases and particle acceleration in the outer heliosphere

International Nuclear Information System (INIS)

Van Allen, J.A.; Mihalov, J.D.

1990-01-01

Major solar flare activity in 1989 has provided examples of the local acceleration of protons at 28 AU (Pioneer 11) and of the propagation of Forbush decreases in galactic cosmic ray intensity to a heliocentric radial distance of 47 AU (Pioneer 10). The combination of these and previous data at lesser distances shows (a) that Forbush decreases propagate with essentially constant magnitude to (at least) 47 AU and with similar magnitude at widely different ecliptic longitudes and (b) that the times for recovery from such decreases become progressively greater as the radial distance increases, being of the order of months in the outer heliosphere. A phenomenological scheme for (b) is proposed and fresh support is given to the hypothesis that the solar cycle modulation of the galactic cosmic ray intensity is attributable primarily to overlapping Forbush decreases which are more frequent and of greater magnitude near times of maximum solar activity than at times of lesser activity

Humidity measurement using alpha-ray and beta-ray

International Nuclear Information System (INIS)

Matsumoto, Shigeaki; Kobayashi, Hisanobu

1981-01-01

Two new hygrometers using radioisotopes were proposed, and the results of tests are described. The one is a dew-point hygrometer utilizing the backscattering phenomena of beta-ray by dew, and the other is a hygrometer by measuring the variation of ionization current by alpha ray due to humidity. The backscattering of beta-ray depends on the atomic number of scatters and the energy of beta-ray. Therefore, the backscattering from dew on a gold plate is different from that from the gold itself. The temperature dependence of the backscattering intensity was measured with a GM counter. Decrease of the intensity was seen at the dew point. A control circuit was designed to measure the dew point automatically. The error of the measurement was within 1 degree C. An alpha-ray ionization hygrometer was constructed. The dependence of ionization current on humidity was measured with an operational amplifier. The resolution of humidity measurement was within 5 percent. (Kato, T.)

Energy and CKT dependence of proton induced L subshell X-ray intensity ratios in elements 57≤Z≤92

International Nuclear Information System (INIS)

Thakkar, Rohit; Sharma, Babita; Allawadhi, K.L.

2006-01-01

The dependence of L subshell X-ray intensity ratios on incident proton energy and the CK transitions has been investigated in elements 57≤Z≤92. The intensity ratio I(L α )/I(L l ) neither shows variation with energy nor any dependence on the CK transitions. In general, the ratios I(L α )/I(L β ) and I(L α )/I(L γ ), first increase with incident proton energy, attain a maximum value, then start decreasing and attain an almost constant value after a particular energy (ranging from about 4.6 MeV for La to 5.8 MeV for U). A comparison has been made among the intensity ratios evaluated using three different sets of parameters. A maximum difference of about 18% has been observed among the different values

ANALYSIS AND MITIGATION OF X-RAY HAZARD GENERATED FROM HIGH INTENSITY LASER-TARGET INTERACTIONS

Energy Technology Data Exchange (ETDEWEB)

Qiu, R.; Liu, J.C.; Prinz, A.A.; Rokni, S.H.; Woods, M.; Xia, Z.; /SLAC

2011-03-21

Interaction of a high intensity laser with matter may generate an ionizing radiation hazard. Very limited studies have been made, however, on the laser-induced radiation protection issue. This work reviews available literature on the physics and characteristics of laser-induced X-ray hazards. Important aspects include the laser-to-electron energy conversion efficiency, electron angular distribution, electron energy spectrum and effective temperature, and bremsstrahlung production of X-rays in the target. The possible X-ray dose rates for several femtosecond Ti:sapphire laser systems used at SLAC, including the short pulse laser system for the Matter in Extreme Conditions Instrument (peak power 4 TW and peak intensity 2.4 x 10{sup 18} W/cm{sup 2}) were analysed. A graded approach to mitigate the laser-induced X-ray hazard with a combination of engineered and administrative controls is also proposed.

Disparity in formulations used for fluorescent X-ray intensity measurements

International Nuclear Information System (INIS)

Mittal, Raj; Gupta, Sheenu

2011-01-01

The paper presents a problem in computations of X-ray fluorescence cross-sections, shell/sub-shell fluorescence yields, Coster-Kronig yields, vacancy alignment, etc. from X-ray fluorescence (XRF) studies. While using barn/atom as a unit for cross-sections if the atomic masses are not considered it causes a discrepancy in the measured cross-section, yield and alignment values. Most of the earlier publications are being quoted where such an oversight has occurred and discrepancy is evident. - Highlights: → Manuscript gives basic formulation for measurements of fluorescent X-ray intensities. → Most publications ignored the fact that use of barn/atom units for cross-sections requires atomic masses. → Published experimental results higher by a factor ≥2 or less by factor 1/M K . → Inspection of published data on XRF parameters needed.

A beam intensity monitor for the evaluation beamline for soft x-ray optical elements

International Nuclear Information System (INIS)

Imazono, Takashi; Moriya, Naoji; Harada, Yoshihisa; Sano, Kazuo; Koike, Masato

2012-01-01

Evaluation Beamline for Soft X-Ray Optical Elements (BL-11) at the SR Center of Ritsumeikan University has been operated to measure the wavelength and angular characteristics of soft x-ray optical components in a wavelength range of 0.65-25 nm using a reflecto-diffractometer (RD). The beam intensity monitor that has been equipped in BL-11 has observed the signal of the zero-th order light. For the purpose of more accurate evaluation of the performance of optical components, a new beam intensity monitor to measure the intensity of the first order light from the monochromator in BL-11 has been developed and installed in just front of RD. The strong positive correlation between the signal of the beam monitor and a detector equipped in the RD is shown. It is successful that the beam intensity of the first order light can be monitored in real time.

High-intensity, subkolovolt x-ray calibration facility using a Cockroft--Walton proton accelerator

International Nuclear Information System (INIS)

Kuckuck, R.W.; Gaines, J.L.; Ernst, R.D.

1976-01-01

Considerable need has arisen for the development of well-calibrated x-ray detectors capable of detecting photons with energies between 100 and 1000 electron-volts. This energy region is of significant interest since the x-ray emission from high-temperature (kT approximately 1.0 keV), laser-produced plasmas is predominantly in this range. A high-intensity, subkilovolt x-ray calibration source was developed which utilizes proton-induced inner-shell atomic fluorescence of low-Z elements. The high photon yields and low bremsstrahlung background associated with this phenomenon are ideally suited to provide an intense, nearly monoenergetic x-ray calibration source for detector development applications. The proton accelerator is a 3 mA, 300 kV Cockroft-Walton using a conventional rf hydrogen ion source. Seven remotely-selectable liquid-cooled targets capable of heat dissipation of 5 kW/cm 2 are used to provide characteristic x-rays with energies between 100 and 1000 eV. Source strengths are of the order of 10 13 to 10 14 photons/sec. A description of the facility is presented. Typical x-ray spectra (B-K, C-K, Ti-L, Fe-L and Cu-L) and flux values will be shown. Problems such as spectral contamination due to carbon buildup on the target and to backscattered particles are discussed

Pulsed x-ray imaging of high-density objects using a ten picosecond high-intensity laser driver

Science.gov (United States)

Rusby, D. R.; Brenner, C. M.; Armstrong, C.; Wilson, L. A.; Clarke, R.; Alejo, A.; Ahmed, H.; Butler, N. M. H.; Haddock, D.; Higginson, A.; McClymont, A.; Mirfayzi, S. R.; Murphy, C.; Notley, M.; Oliver, P.; Allott, R.; Hernandez-Gomez, C.; Kar, S.; McKenna, P.; Neely, D.

2016-10-01

Point-like sources of X-rays that are pulsed (sub nanosecond), high energy (up to several MeV) and bright are very promising for industrial and security applications where imaging through large and dense objects is required. Highly penetrating X-rays can be produced by electrons that have been accelerated by a high intensity laser pulse incident onto a thin solid target. We have used a pulse length of 10ps to accelerate electrons to create a bright x-ray source. The bremsstrahlung temperature was measured for a laser intensity from 8.5-12×1018 W/cm2. These x-rays have sequentially been used to image high density materials using image plate and a pixelated scintillator system.

Intense Non-Linear Soft X-Ray Emission from a Hydride Target during Pulsed D Bombardment

Science.gov (United States)

Miley, George H.; Yang, Yang; Lipson, Andrei; Haque, Munima; Percel, Ian; Romer, Michael

Radiation emission from low-energy nuclear radiation (LENR) electrodes (both charged-particle and X-rays) represents an important feature of LENR in general. Here, calibration, measurement techniques, and soft X-ray emission results from deuterium bombardment of a Pd target (cathode) placed in a pulsed deuterium glow discharge (PGD) are described. An X-ray intensity of 13.4 mW/cm2 and a dose of 3.3 μJ/cm2 were calculated over a 0.5 ms pulse time from AXUV photodiode radiation detector measurements. A most striking feature is that X-ray energies >600 V are observed with a discharge voltage only about half of that value. To further investigate this phenomenon, emission during room temperature D-desorption from electrolytically loaded Pd:Dx cathodes was also studied. The X-ray emission energy observed was quite similar to the PGD case. However, the intensity in this case was almost 13 orders of magnitude lower due to the much lower deuterium fluxes involved.

Intense non-linear soft X-ray emission from a hydride target during pulsed D bombardment

International Nuclear Information System (INIS)

Miley, George H.; Yang, Yang; Lipson, Andrei; Haque, Munima; Percel, Ian; Romer, Michael

2006-01-01

Radiation emission from low-energy nuclear radiation (LENR) electrodes (both charged-particle and X-rays) represents an important feature of LENR in general. Here, calibration, measurement techniques, and soft X-ray emission results from deuterium bombardment of a Pd target (cathode) placed in a pulsed deuterium glow discharge (PGD) are described. An X-ray intensity of 13.4 mW/cm 2 and a dose of 3.3 μJ/cm 2 were calculated over a 0.5 ms pulse time from AXUV photodiode radiation detector measurements. A most striking feature is that X-ray energies >600 V are observed with a discharge voltage only about half of that value. To further investigate this phenomenon, emission during room temperature D-desorption from electrolytically loaded Pd:Dx cathodes was also studied. The X-ray emission energy observed was quite similar to the PGD case. However, the intensity in this case was almost 13 orders of magnitude lower due to the much lower deuterium fluxes involved. (author)

Pionic X-ray intensities from C, CH2 and CD2

International Nuclear Information System (INIS)

Daniel, H.; Seki, R.

1980-01-01

The relative intensities of the carbon Lsub(α) and Lsub(β) pionic X-ray lines from graphite, polyethylene, and deuterated polyethylene have been measured. No differences between CH 2 and CD 2 were observed, but differences were found between graphite and the two polyethylene targets. (orig.)

The relative-intensity method of X-ray fluorescence analysis and its application to soils and rocks

International Nuclear Information System (INIS)

Childs, C.W.; Furkert, R.J.

1974-01-01

The relative-intensity X-ray fluorescence method of analysis of rock and soil samples has been investigated and compared with the net-intensity method. Strong, coherently scattered radiation originating from the X-ray tube is shown to be preferable to background radiation as an internal standard, and scattered radiation measured at one wavelength can usefully be applied in the determination of several elements. When the concentrations of an element in two soil samples of different composition (for example concretions and the soil adjacent to them) are compared, the ratio of the relative intensities may be different from the ratio of net intensities by a factor of about two. The concentrations of manganese in thirteen standard rock samples determined by the relative-intensity method are within or very close to the ranges of values reported previously

Approximated transport-of-intensity equation for coded-aperture x-ray phase-contrast imaging.

Science.gov (United States)

Das, Mini; Liang, Zhihua

2014-09-15

Transport-of-intensity equations (TIEs) allow better understanding of image formation and assist in simplifying the "phase problem" associated with phase-sensitive x-ray measurements. In this Letter, we present for the first time to our knowledge a simplified form of TIE that models x-ray differential phase-contrast (DPC) imaging with coded-aperture (CA) geometry. The validity of our approximation is demonstrated through comparison with an exact TIE in numerical simulations. The relative contributions of absorption, phase, and differential phase to the acquired phase-sensitive intensity images are made readily apparent with the approximate TIE, which may prove useful for solving the inverse phase-retrieval problem associated with these CA geometry based DPC.

Mapping the continuous reciprocal space intensity distribution of X-ray serial crystallography.

Science.gov (United States)

Yefanov, Oleksandr; Gati, Cornelius; Bourenkov, Gleb; Kirian, Richard A; White, Thomas A; Spence, John C H; Chapman, Henry N; Barty, Anton

2014-07-17

Serial crystallography using X-ray free-electron lasers enables the collection of tens of thousands of measurements from an equal number of individual crystals, each of which can be smaller than 1 µm in size. This manuscript describes an alternative way of handling diffraction data recorded by serial femtosecond crystallography, by mapping the diffracted intensities into three-dimensional reciprocal space rather than integrating each image in two dimensions as in the classical approach. We call this procedure 'three-dimensional merging'. This procedure retains information about asymmetry in Bragg peaks and diffracted intensities between Bragg spots. This intensity distribution can be used to extract reflection intensities for structure determination and opens up novel avenues for post-refinement, while observed intensity between Bragg peaks and peak asymmetry are of potential use in novel direct phasing strategies.

Registration of intensive hard X-rays and soft gamma-rays from the thunderstorm clouds at Tien-Shan installation Adron

International Nuclear Information System (INIS)

Antonova, V.P.; Kryukov, S.V.; Vil'danova, L.I.; Gurevich, A.V.; Zybin, K.P.; Kokobaev, M.M.; Nesterova, N.M.; Piskal', V.V.; Ptitsyn, M.O.; Chubenko, A.P.; Shchepetov, A.L.

2001-01-01

The Adron installation mounted at the Tien-Shan station is intended for studying the extensive air showers. The Adron installation consists of a neutron supermonitor charged particles detector, muon detector and detector for registering the hard X-ray and soft gamma-radiation from the thunderstorm clouds accomplished on the basis of the Geiger-Mueller counters with sensitivity area of 16-17 m 2 . The intensive fluxes of the hard X-ray and soft gamma-radiation from the thunderstorm clouds passing over the Adron installation at the height below 1 km are registered using this installation. The short-time radiation flares of 1-5 min duration are separated at the background of the intensity slow change. This testifies to the benefit of existence of the runaway electron effect in the thunderstorm clouds [ru

Use of Ventilator Bundle and Staff Education to Decrease Ventilator-Associated Pneumonia in Intensive Care Patients.

Science.gov (United States)

Parisi, Maria; Gerovasili, Vasiliki; Dimopoulos, Stavros; Kampisiouli, Efstathia; Goga, Christina; Perivolioti, Efstathia; Argyropoulou, Athina; Routsi, Christina; Tsiodras, Sotirios; Nanas, Serafeim

2016-10-01

Ventilator-associated pneumonia (VAP), one of the most common hospital-acquired infections, has a high mortality rate. To evaluate the incidence of VAP in a multidisciplinary intensive care unit and to examine the effects of the implementation of ventilator bundles and staff education on its incidence. A 24-month-long before/after study was conducted, divided into baseline, intervention, and postintervention periods. VAP incidence and rate, the microbiological profile, duration of mechanical ventilation, and length of stay in the intensive care unit were recorded and compared between the periods. Of 1097 patients evaluated, 362 met the inclusion criteria. The baseline VAP rate was 21.6 per 1000 ventilator days. During the postintervention period, it decreased to 11.6 per 1000 ventilator days (P = .01). Length of stay in the intensive care unit decreased from 36 to 27 days (P = .04), and duration of mechanical ventilation decreased from 26 to 21 days (P = .06). VAP incidence was high in a general intensive care unit in a Greek hospital. However, implementation of a ventilator bundle and staff education has decreased both VAP incidence and length of stay in the unit. ©2016 American Association of Critical-Care Nurses.

Bilateral Pulvinar Signal Intensity Decrease on T2-Weighted Images in Patients with Aspartylglucosaminuria

International Nuclear Information System (INIS)

Autti, T.; Loennqvist, T.; Joensuu, R.

2008-01-01

Background: Aspartylglucosaminuria (AGU) is an autosomal recessive lysosomal disease caused by deficiency of aspartylglucosaminidase. A thalamic T2 signal intensity decrease is associated with lysosomal diseases. Purpose: To investigate thalamic signal intensity in AGU by performing a retrospective review of brain magnetic resonance (MR) imaging studies of AGU patients. Material and Methods: A total of 25 MR examinations were available for 11 patients aged between 3 and 32 years (four patients underwent bone marrow transplantation). Of these, 13 examinations were performed after bone marrow transplantation. Five patients had from two to six examinations, and six patients had one examination each. In every patient, the diagnosis of AGU was confirmed by blood and urine tests. Eighteen examinations were performed with a 1.0T imager including dual spin-echo T2 and proton density (PD) axial and coronal images, and 10 examinations also included T1-weighted images. Seven examinations were performed with a 1.5T imager including turbo spin-echo axial and coronal T2-weighted images and axial fluid-attenuated inversion recovery (FLAIR) images; three examinations included T1-weighted three-dimensional magnetization-prepared rapid acquisition gradient-echo (3D MPRAGE) images. The signal intensity of the thalamus and pulvinar in every sequence was compared to that of the putamina. Results: In AGU, thalamic alterations were first detectable on T2-weighted images (25 examinations in 11 patients) from the age of 3 years 6 months, showing decreased signal intensity in 21 of 24 examinations. T1-weighted images (13 examinations) showed slightly increased thalamic signal intensity in five out of seven examinations from the age of 7 years, and PD images (19 examinations) showed decreased signal intensity from the age of 16 years (three examinations). The pulvinar showed decreased signal intensity on spin-echo T2-weighted images for 14 of 18 examinations or on FLAIR sequences for seven

An Industrial Radipgraphy Exposure Device Based on Measurement of Transmitted Gamma-Ray Intensity

International Nuclear Information System (INIS)

Polee, C.; Chankow, N.; Srisatit, S.; Thong-Aram, D.

2014-01-01

In film radiography, underexposure and overexposure may happen particularly when lacking knowledge of specimen material and hollowness. This paper describes a method and a device for determining exposure in industrial gamma-ray radiography based on quick measurement of transmitted gamma-ray intensity with a D3372 Hamamatsu small GM tube. Application software is developed for Android mobile phone to remotely control the device and to display the counting data via Bluetooth. Prior to placing film, the device is placed behind the specimen to be radiographed to determine the exposure time from the transmitted intensity which is independent on source activity, source-to-film distance, specimen thickness and kind of material. The developed technique and device make radiographic process economic, convenient and more reliable.

The response of clouds and aerosols to cosmic ray decreases

DEFF Research Database (Denmark)

Svensmark, J.; Enghoff, Martin Andreas Bødker; Shaviv, N. J.

2016-01-01

A method is developed to rank Forbush Decreases (FDs) in the galactic cosmic ray radiation according to their expected impact on the ionization of the lower atmosphere. Then a Monte Carlo bootstrap based statistical test is formulated to estimate the significance of the apparent response in physi......A method is developed to rank Forbush Decreases (FDs) in the galactic cosmic ray radiation according to their expected impact on the ionization of the lower atmosphere. Then a Monte Carlo bootstrap based statistical test is formulated to estimate the significance of the apparent response...... in physical and micro-physical cloud parameters to FDs. The test is subsequently applied to one ground based and three satellite based datasets. Responses (> 95%) to FDs are found in the following parameters of the analyzed datasets. AERONET: Ångström exponent (cloud condensation nuclei changes), SSM...... with the strength of the FDs, and the signs and magnitudes of the responses agree with model based expectations. The effect is mainly seen in liquid clouds. An impact through changes in UV driven photo chemistry is shown to be negligible and an impact via UV absorption in the stratosphere is found to have no effect...

Average features of cosmic ray variation associated with sudden commencement of magnetic storm

International Nuclear Information System (INIS)

Wada, Masami; Suda, Tomoshige.

1980-01-01

In order to obtain average features of cosmic ray variation associated with a passage of shock front in space, superposed epoch analysis of cosmic ray intensity with respect to the time of occurrence of sudden commencement (SC) of magnetic storm during solar cycle 20, 1964 - 1975, is carried out for hundreds of SC. When SC's are distributed evenly over the day, the onset in cosmic ray decrease is seen clearly within one hour of SC, followed by a sharp decrease in the intensity, but without any precursory fluctuation. The magnitude distribution and the rigidity spectrum for maximum depression show the features of Forbush decrease (FD). Superposed epoch analysis is also applied to solar wind and the interplanetary magnetic field data, and their relation to cosmic ray variation is studied. Effects of the superposition of the isotropic and anisotropic variations on the time profile of cosmic ray intensity observed at a station are discussed. (author)

Intense soft x-rays from RS Ophiuchi during the 1985 outburst

International Nuclear Information System (INIS)

Mason, K.O.; Cordova, F.A.; Bode, M.F.; Barr, P.

1985-01-01

Intense soft x-ray emission with a characteristic temperature of a few million degrees has been detected from the recurrent nova RS Oph approximately two months after its January 1985 optical outburst. This is the first detection of x-rays from such a system at outburst. The x-radiation is interpreted as emission from circumstellar gas that is shock heated by the passage of the blast wave from the nova explosion. The rapid decline of the x-ray flux between about 60 and 90 days after the outburst probably occurs because the blast wave has reached the edge of the volume filled, between outbursts, by the stellar wind of the red giant component of the binary system. Residual x-ray emission detected from RS Oph 250 days after the outburst is interpreted as coming from the surface of a white dwarf, at a temperature of approx.300,000K, where thermonuclear burning is persisting. 7 refs., 3 figs

High-resolution imaging of coronary calcifications by intense low-energy fluoroscopic X-ray obtained from synchrotron radiation

Energy Technology Data Exchange (ETDEWEB)

Ohtsuka, S.; Sugishita, Y.; Takeda, T.; Itai, Y.; Tada, J.; Hyodo, K.; Ando, M. [Inst. of Clinical Medicine, Univ. of Tsukuba, Ibaraki (Japan). Dept. of Cardiology

2000-07-01

In order to obtain an intense monochromatic low-energy X-ray from synchrotron radiation (SR) and apply it to detect coronary calcifications, the SR beam was reflected with a silicon crystal to be expanded (150 mm in height and 80 mm in width) and to be monochromatized at an energy level of 37 keV. The X-ray was intermittently irradiated to obtain dynamic imaging of 30 images/s. Images were recorded by a digital fluorography system. The low-energy X-ray from SR sharply visualized calcification of coronary arteries, while conventional X-ray could not visualize coronary calcification. The intense monochromatic low-energy X-ray from SR is sensitive, has high-resolution for imaging coronary calcification and may serve as a screening method for coronary artery disease.

Solar flare location effect on the spectral characteristics of the diurnal anisotropy of cosmic ray intensity

Energy Technology Data Exchange (ETDEWEB)

Yadava, R S; Kumar, S; Naqvi, T N [Aligarh Muslim Univ. (India)

1977-01-01

The spectral parameters of the diurnal anisotropy of cosmic ray intensity are studied separately for days where the solar flares have occurred on the western limb as well as on the eastern limb of the solar disc for both nucleonic as well as mesonic components of the cosmic rays. It is observed that the diurnal amplitude of the cosmic ray intensity in space is larger for days where solar flares have occurred on the western limb of the solar disc as compared to the days where solar flares have occurred on the eartern limb of the solar disc. This is true in both nucleonic as well as mesonic components of the cosmic ray intensity. The average value of the direction in space of diurnal anisotropy in local asymptotic time for various stations is almost same and is observed at around the same hours for flares which occur on the western as well as eastern limb of the solar disc. When these results are compared with the direction of the diurnal anisotropy in space on quiet days, it is found that the direction of the diurnal anisotropy on days where solar flares have occurred on the western limb as well as eastern limb of the solar disc is earlier in comparison to quiet days. This phase shift towards earlier hours is about three hours for nucleonic as well as mesonic components of the cosmic rays intensity. The variation of the rigidity exponent observed on different types of days for the nucleonic component has also been discussed.

Bright ultrashort x-rays from intense subpicosecond laser-plasma interactions

International Nuclear Information System (INIS)

Umstadter, D.

1995-01-01

Short-pulse, high-intensity lasers interacting with solid targets make possible the study of a new class of laser-plasma interactions. They are unique because during the ultrashort laser pulse relatively little expansion occurs, and the density scale length remains much less than the laser wavelength. This makes possible the direct deposition of a significant amount of the laser energy at close to solid density. Steep plasma temperature and density gradients subsequently cause rapid cooling, resulting in highly non-equilibrium conditions and the concurrent emission of extremely bright ultrashort x-ray pulses. In this study, the latter are investigated experimentally with temporally and spectrally resolved soft x-ray diagnostics. The emitted x-ray spectra from solid targets with various atomic numbers are characterized for a laser pulse width τ l ∼ 400 fs. These ultrashort x rays may be used as (1) a diagnostic of solid-density plasma conditions, (2) a tool for the study of radiation hydrodynamics in a parameter regime that is otherwise inaccessible, and (3) a source for time-resolved diffraction, spectroscopy, or microscopy studies of transient chemical, biological or physical phenomena

The design of a measuring system for soft X ray absolute intensity

International Nuclear Information System (INIS)

Cui Congwu; Cui Mingqi

1997-01-01

The design of a measuring system for soft X ray absolute intensity in detail is presented. The system consists of two parts: the ionization chamber, the silicon photodiode and its transferring system. The system can be used as the primary standard detector for the measurement of soft X ray absolute radiation flux in the energy range of 50 to 2000 eV after being calibrated. The whole system will be installed to the newly built beamline of 3W1B at Beijing Synchrotron Radiation Facility

Measurement of relative L X-ray intensity ratio following radioactive decay and photoionization

Energy Technology Data Exchange (ETDEWEB)

Yalcin, P. [Department of Science Education, Faculty of Education, Erzincan University, 24030 Erzincan (Turkey)], E-mail: pasayalcin@hotmail.com; Porikli, S.; Kurucu, Y.; Sahin, Y. [Department of Physics, Faculty of Sciences, Atatuerk University, 25240 Erzurum (Turkey)

2008-05-22

The measurements of the L X-ray intensity ratio I(L{alpha})/I(L{beta}), I(L{alpha})/I(L{gamma}), I(L{alpha})/I(L{iota}), I(L{beta})/I(L{gamma}) and I(L{iota})/I(L{gamma}) for elements Dy, Ho, Yb, W, Hg, Tl and Pb were experimentally determined both by photon excitation, in which 59.5 keV {gamma}-rays from a filtered radioisotope {sup 241}Am was used, and by the radioactive decay of {sup 160}Tb, {sup 160}Er, {sup 173}Lu, {sup 182}Re, {sup 201}Tl, {sup 203}Pb and {sup 207}Bi. L X-rays emitted by samples were counted by a Si(Li) detector with resolution 160 eV at 5.9 keV. Obtained values were compared with the calculated theoretical values. Theoretical values of the I(L{alpha}/L{beta}), I(L{alpha}/L{gamma}), I(L{alpha}/L{iota}), I(L{beta}/L{gamma}) and I(L{iota}/L{gamma}) intensity ratios were calculated using theoretically tabulated values of subshell photoionization cross-section, fluorescence yield, fractional X-ray emission rates, Coster-Kronig transition probabilities. It was observed that present values agree with previous theoretical and other available experimental results.

An industrial radiography exposure device based on measurement of transmitted gamma-ray intensity

International Nuclear Information System (INIS)

Polee, C; Chankow, N; Srisatit, S; Thong-Aram, D

2015-01-01

In film radiography, underexposure and overexposure may happen particularly when lacking information of specimen material and hollowness. This paper describes a method and a device for determining exposure in industrial gamma-ray radiography based on quick measurement of transmitted gamma-ray intensity with a small detector. Application software was developed for Android mobile phone to remotely control the device and to display counting data via Bluetooth communication. Prior to film exposure, the device is placed behind a specimen to measure transmitted intensity which is inversely proportional to the exposure. Unlike in using the conventional exposure curve, correction factors for source decay, source-to- film distance, specimen thickness and kind of material are not needed. The developed technique and device make radiographic process economic, convenient and more reliable. (paper)

Periodic variations of cosmic ray intensity with period of -37 minute observed on April 25th, 1984

International Nuclear Information System (INIS)

Sakai, Takasuke; Kato, Masahito; Takei, Ryoji; Tamai, Eiji

1985-01-01

Existence of cosmic ray variation with period ranging from a few hours to seconds during geomagnetically quiet and perturb period at different altitude with different detector, was reported previously. As short period variation is thought to be transient with small amplitude fluctuation, consequently high counting rate of cosmic ray and appropriate method for finding short periodicity, is required. Further, there is similar phenomenon in which short variation, followed by storm sudden commencement (SSC) and/or Forbush decrease (FD) occurs. In 1979, Kato et al. used 3 minutes data at Mt. Norikura and obtained -6 x 10 5 count/min, and tried to find out short periodicity of cosmic ray around SSC, but no clear conclusion was obtained. T. Sakai, et al., used plastic scintillation counter of Akeno observatory, following their preceding work. The counter has an area about 154 m 2 . High counting rate of -2 x 10 6 counts/min. was observed at Akeno which revealed the existence of -37 minute periodical oscillation with an amplitude of 0.1 % in p-p during the time period of 1300 - 1900 UT on April 25th 1984, one day before FD. Observed periodical oscillation of cosmic ray counting rate may be the result of the changes in magnetic field. But, it must be noted that there remains possibility of oscillation of cosmic ray intensity in the interplanetary space during the period, independent of geomagnetic field. (author)

MIT/OSO 7 catalog of x-ray sources: intensities, spectra, and long-term variability

International Nuclear Information System (INIS)

Markert, T.H.; Winkler, P.F.; Laird, F.N.; Clark, G.W.; Hearn, D.R.; Sprott, G.F.; Li, F.K.; Bradt, H.V.; Lewin, W.H.G.; Schnopper, H.W.

1979-01-01

This paper is a summary of the observations of the cosmic X-ray sky performed by the MIT 1--40 KeV X-ray detectors on the OSO 7 between 1971 October and 1973 May. Specifically, we have computed the mean intensities or upper limits of all third Uhuru or OSO 7 cataloged sources (185 sources) in the 3--10 KeV range. For those sources for which a statistically significant (>20) intensity was found in the 3--10 KeV band (138 sources), further intensity determinations were made in the 1--15 KeV, 1--6 KeV, and 15--40 KeV energy bands. We have provided graphs and other simple techniques to aid the user in converting the observed counting rates to convenient units and in determining spectral parameters. Finally, we have plotted long-term light curves (counting rates in one or more energy bands as a function of time) for 86 of the brighter sources

A photodiode amplifier system for pulse-by-pulse intensity measurement of an x-ray free electron laser.

Science.gov (United States)

Kudo, Togo; Tono, Kensuke; Yabashi, Makina; Togashi, Tadashi; Sato, Takahiro; Inubushi, Yuichi; Omodani, Motohiko; Kirihara, Yoichi; Matsushita, Tomohiro; Kobayashi, Kazuo; Yamaga, Mitsuhiro; Uchiyama, Sadayuki; Hatsui, Takaki

2012-04-01

We have developed a single-shot intensity-measurement system using a silicon positive-intrinsic-negative (PIN) photodiode for x-ray pulses from an x-ray free electron laser. A wide dynamic range (10(3)-10(11) photons/pulse) and long distance signal transmission (>100 m) were required for this measurement system. For this purpose, we developed charge-sensitive and shaping amplifiers, which can process charge pulses with a wide dynamic range and variable durations (ns-μs) and charge levels (pC-μC). Output signals from the amplifiers were transmitted to a data acquisition system through a long cable in the form of a differential signal. The x-ray pulse intensities were calculated from the peak values of the signals by a waveform fitting procedure. This system can measure 10(3)-10(9) photons/pulse of ~10 keV x-rays by direct irradiation of a silicon PIN photodiode, and from 10(7)-10(11) photons/pulse by detecting the x-rays scattered by a diamond film using the silicon PIN photodiode. This system gives a relative accuracy of ~10(-3) with a proper gain setting of the amplifiers for each measurement. Using this system, we succeeded in detecting weak light at the developmental phase of the light source, as well as intense light during lasing of the x-ray free electron laser. © 2012 American Institute of Physics

2-D Modelling of Long Period Variations of Galactic Cosmic Ray Intensity

International Nuclear Information System (INIS)

Siluszyk, M; Iskra, K; Alania, M

2015-01-01

A new two-dimensional (2-D) time dependent model describing long-period variations of the Galactic Cosmic Ray (GCR) intensity has been developed. New approximations for the changes of the magnitude B of the Interplanetary Magnetic Field (IMF), the tilt angle δ of the Heliospheric Neutral Sheet (HNS) and drift effects of the GCR particles have been included into the model. Moreover, temporal changes of the exponent γ expressing the power law - rigidity dependence of the amplitudes of the 11-year variation of the GCR intensity have been added. We show that changes of the expected GCR particle density precedes changes of the GCR intensity measured by the Moscow Neutron (MN) monitor by about 18 months. So ∼18 months can be taken as an effective delay time between the expected intensity caused by the combined influence of the changes of the parameters implemented in the time-dependent 2-D model and the GCR intensity measured by neutron monitors during the 21 cycle of solar activity. (paper)

Experimental study of soft X-ray intensity with different anode tips in ...

Indian Academy of Sciences (India)

2016-06-15

Jun 15, 2016 ... c Indian Academy of Sciences. DOI 10.1007/s12043-016-1224-8. Experimental study of soft X-ray intensity with different anode tips in Amirkabir plasma focus device. MORTEZA HABIBI. ∗ and MAHSA MAHTAB. Energy Engineering and Physics Department, Amirkabir University of Technology, Tehran, Iran.

A γ-ray survey along Hanaore fault

International Nuclear Information System (INIS)

Mino, Kazuo

1978-01-01

The γ-ray survey was carried out by a scintillation survey meter at O-hara area near around Hanaore Fault Zone in the northern part of Kyoto. The survey was done several times over along the same observational line. Static pattern of γ-ray intensity is revealed similar one in each other, even there is small difference. Strong intensity of γ-ray means subsistance of crushed rocks zone and a huge fault as Hanaore consists of the structure made by these weak zones. A pretty large earthquake among microearthquakes was occurred, fortunately for us, during survey period. The γ-ray survey was done just on January 6, 1978 when it was just one day before the earthquake. The observational results before the earthquake, did not give large variations of γ-ray intensity. But after 5 days from the earthquake, that is January 11, the intensity of γ-ray decreases into low value, over observational error, at almost all stations. The improvement of γ-ray was found after 2 weeks from the earthquake. Ordinarily the large fault as Hanaore is one of boundaries around block of crust, and fault zone is more sensitive to geophysical activity in the crust. Continuous observation of γ-ray will give the solution to corelation with earthquake or earthquake prediction. (author)

Direct intensity calibration of X-ray grazing-incidence microscopes with home-lab source

Science.gov (United States)

Li, Yaran; Xie, Qing; Chen, Zhiqiang; Xin, Qiuqi; Wang, Xin; Mu, Baozhong; Wang, Zhanshan; Liu, Shenye; Ding, Yongkun

2018-01-01

Direct intensity calibration of X-ray grazing-incidence microscopes is urgently needed in quantitative studies of X-ray emission from laser plasma sources in inertial confinement fusion. The existing calibration methods for single reflecting mirrors, crystals, gratings, filters, and X-ray detectors are not applicable for such X-ray microscopes due to the specific optical structure and the restrictions of object-image relation. This article presents a reliable and efficient method that can be performed using a divergent X-ray source and an energy dispersive Si-PIN (silicon positive-intrinsic-negative) detector in an ordinary X-ray laboratory. The transmission theory of X-ray flux in imaging diagnostics is introduced, and the quantities to be measured are defined. The calibration method is verified by a W/Si multilayer-coated Kirkpatrick-Baez microscope with a field of view of ˜95 μm at 17.48 keV. The mirror reflectance curve in the 1D coordinate is drawn with a peak value of 20.9% and an uncertainty of ˜6.0%.

A more general expression for the average X-ray diffraction intensity of crystals with an incommensurate one-dimensional modulation

International Nuclear Information System (INIS)

Lam, E.J.W.; Beurskens, P.T.; Smaalen, S. van

1994-01-01

Statistical methods are used to derive an expression for the average X-ray diffraction intensity, as a function of (sinθ)/λ, of crystals with an incommensurate one-dimensional modulation. Displacive and density modulations are considered, as well as a combination of these two. The atomic modulation functions are given by truncated Fourier series that may contain higher-order harmonics. The resulting expression for the average X-ray diffraction intensity is valid for main reflections and low-order satellite reflections. The modulation of individual atoms is taken into account by the introduction of overall modulation amplitudes. The accuracy of this expression for the average X-ray diffraction intensity is illustrated by comparison with model structures. A definition is presented for normalized structure factors of crystals with an incommensurate one-dimensional modulation that can be used in direct-methods procedures for solving the phase problem in X-ray crystallography. A numerical fitting procedure is described that can extract a scale factor, an overall temperature parameter and overall modulation amplitudes from experimental reflection intensities. (orig.)

Investigation of L X-ray intensity ratios in Pt induced by proton collisions

International Nuclear Information System (INIS)

Kaur, Manpuneet; Kaur, Mandeep; Mohan, Harsh; Jain, Arvind Kumar; Singh, Parjit S.; Vohra, Neelam; Sharma, Sunita

2015-01-01

A survey of literature on L X-ray parameters inspires us for taking up the present investigation. These parameters are useful to study atomic properties. In view of this, we report L X-ray intensity ratios for Pt, namely, L ℓ / L α , L β / L α and L γ / L α with proton collisions over the energy range 260 - 400 keV with an interval of 20 keV. The intention of research presented in this paper is to explore their energy dependence and comparison with theoretical calculations. These analyses will yield a data in the low energy region which assist in better clarity of proton induced X-ray emission phenomenon

Evaluating the Use of Tissue Oximetry to Decrease Intensive Unit Monitoring for Free Flap Breast Reconstruction.

Science.gov (United States)

Ricci, Joseph A; Vargas, Christina R; Ho, Olivia A; Lin, Samuel J; Tobias, Adam M; Lee, Bernard T

2017-07-01

Postoperative free flap care has historically required intensive monitoring for 24 hours in an intensive care unit. Continuous monitoring with tissue oximetry has allowed earlier detection of vascular compromise, decreasing flap loss and improving salvage. This study aims to identify whether a fast-track postoperative paradigm can be safely used with tissue oximetry to decrease intensive monitoring and costs. All consecutive microsurgical breast reconstructions performed at a single institution were reviewed (2008-2014) and cases requiring return to the operating room were identified. Data evaluated included patient demographics, the take back time course, and complications of flap loss and salvage. A cost-benefit analysis was performed to analyse the utility of a postoperative intensive monitoring setting. There were 900 flaps performed and 32 required an unplanned return to the operating room. There were 16 flaps that required a reexploration within the first 24 hours; the standard length of intensive unit monitoring. After 4 hours, there were 7 flaps (44%) detected by tissue oximetry for reexploration. After 15 hours of intensive monitoring postoperatively, cost analysis revealed that the majority (15/16; 94%) of failing flaps had been identified and the cost of identifying each subsequent failing flap exceeded the cost of another hour of intensive monitoring. The postoperative paradigm for microsurgical flaps has historically required intensive unit monitoring. Using tissue oximetry, a fast-track pathway can reduce time spent in an intensive monitoring setting from 24 to 15 hours with significant cost savings and minimal risk of missing a failing free flap.

Momentum and zenithal dependence of the enhancements of intensities of cosmic ray muons

International Nuclear Information System (INIS)

Abdel-Monem, M.S.; Osborne, A.R.; Benbrook, J.R.; Sheldon, W.R.; Duller, N.M.; Green, P.J.; Choate, L.M.; Magnusson, C.E.

1977-01-01

The absolute directional differential intensities of high-energy cosmic ray muons near sea level have been measured over the momentum range 2-700 GeV/c in the vertical direction and zenithal interval 55deg-90deg. The measurements were made with the AMH magnetic spectrometer-telescope. The enhancements I(65deg)/I(0deg) and I(80deg)/I(0deg) of the muon intensities as a function of momentum are presented and compared with the theoretical results of Maeda and Asbury et al. (author)

Sudden Intensity Increases and Radial Gradient Changes of Cosmic Ray Mev Electrons and Protons Observed at Voyager 1 Beyond 111 AU in the Heliosheath

Science.gov (United States)

Webber, W. R.; Mcdonald, F. B.; Cummings, A. C.; Stone, E. C.; Heikkila, B.; Lal, N.

2012-01-01

Voyager 1 has entered regions of different propagation conditions for energetic cosmic rays in the outer heliosheathat a distance of about 111 AU from the Sun. The low energy 614 MeV galactic electron intensity increased by 20over a time period 10 days and the electron radial intensity gradient abruptly decreased from 19AU to 8AU at2009.7 at a radial distance of 111.2 AU. At about 2011.2 at a distance of 116.6 AU a second abrupt intensity increase of25 was observed for electrons. After the second sudden electron increase the radial intensity gradient increased to18AU. This large positive gradient and the 13 day periodic variations of 200 MeV particles observed near theend of 2011 indicate that V1 is still within the overall heliospheric modulating region. The implications of these resultsregarding the proximity of the heliopause are discussed.

The MIT/OSO 7 catalog of X-ray sources - Intensities, spectra, and long-term variability

Science.gov (United States)

Markert, T. H.; Laird, F. N.; Clark, G. W.; Hearn, D. R.; Sprott, G. F.; Li, F. K.; Bradt, H. V.; Lewin, W. H. G.; Schnopper, H. W.; Winkler, P. F.

1979-01-01

This paper is a summary of the observations of the cosmic X-ray sky performed by the MIT 1-40-keV X-ray detectors on OSO 7 between October 1971 and May 1973. Specifically, mean intensities or upper limits of all third Uhuru or OSO 7 cataloged sources (185 sources) in the 3-10-keV range are computed. For those sources for which a statistically significant (greater than 20) intensity was found in the 3-10-keV band (138 sources), further intensity determinations were made in the 1-15-keV, 1-6-keV, and 15-40-keV energy bands. Graphs and other simple techniques are provided to aid the user in converting the observed counting rates to convenient units and in determining spectral parameters. Long-term light curves (counting rates in one or more energy bands as a function of time) are plotted for 86 of the brighter sources.

Intensity of the absorbing dose of the gamma rays in the air of Krusevac during and after nuclear accident in Chernobil

International Nuclear Information System (INIS)

Fortuna, D.

1997-01-01

In this paper are compared overage daily values of the intensity of the absorbing doses of the gamma rays in the air of Krusevac, during and after nuclear accident in Cernobil. Average daily values of intensity of the absorbing doses of gamma rays in the air of Krusevac, immediately after nuclear accident in Cernobil were, three to seven time higher than of the average daily values of the natural rays. (author)

Propagation and scattering of high-intensity X-ray pulses in dense atomic gases and plasmas

International Nuclear Information System (INIS)

Weninger, Clemens

2015-10-01

Nonlinear spectroscopy in the X-ray domain is a promising technique to explore the dynamics of elementary excitations in matter. X-rays provide an element specificity that allows them to target individual chemical elements, making them a great tool to study complex molecules. The recent advancement of X-ray free electron lasers (XFELs) allows to investigate non-linear processes in the X-ray domain for the first time. XFELs provide short femtosecond X-ray pulses with peak powers that exceed previous generation synchrotron X-ray sources by more than nine orders of magnitude. This thesis focuses on the theoretical description of stimulated emission processes in the X-ray regime in atomic gases. These processes form the basis for more complex schemes in molecules and provide a proof of principle for nonlinear X-ray spectroscopy. The thesis also includes results from two experimental campaigns at the Linac Coherent Light Source and presents the first experimental demonstration of stimulated X-ray Raman scattering. Focusing an X-ray free electron laser beam into an elongated neon gas target generates an intense stimulated X-ray emission beam in forward direction. If the incoming X-rays have a photon energy above the neon K edge, they can efficiently photo-ionize 1s electrons and generate short-lived core excited states. The core-excited states decay mostly via Auger decay but have a small probability to emit a spontaneous X-ray photon. The spontaneous emission emitted in forward direction can stimulate X-ray emission along the medium and generate a highly directional and intense X-ray laser pulse. If the photon energy of the incoming X-rays however is below the ionization edge in the region of the pre-edge resonance the incoming X-rays can be inelastically scattered. This spontaneous X-ray Raman scattering process has a very low probability, but the spontaneously scattered photons in the beginning of the medium can stimulate Raman scattering along the medium. The

L X-ray intensity ratio measurements using selective L sub-shell photo-ionisation on synchrotron

Science.gov (United States)

Bansal, Himani; Tiwari, M. K.; Mittal, Raj

2017-10-01

Lα/Lℓ, Lβ /Lℓ and Lγ/Lℓ intensity ratios have been measured for elements in the range 66≤Z≤83 at tuned photon energies on synchrotron beam line-16 at Indus-2, India. For each element, three incident energies Ei were E3; EL3 EL1 where ELi are Li absorption edge energies of the element. Emitted L X-ray spectrum of an element constitutes a number of X-ray lines generally grouped into four main groups due to limited resolution of available detectors as Lℓ(L3-M1), Lα(L3-M4,5), Lβ(L1-M2,3,4,5,N4; L2-M3,4; L3-N1,4,5,O1,4,5) and Lγ(L2-N1,4,O1,4; L1-N2,3,5,O3,2). Lα and Lℓ both comprise only the lines feeding L3 level and Lβ group comprises X-ray lines feeding all the three sub-shells where as Lγ involves contribution from L1 and L2 feedings. Only E3 excitation gives the ratios free from intra sub-shell Coster-Kronig (CK) transitions while excitations E2 and E1 give CK affected Lβ/Lℓ and Lγ/Lℓ X-ray intensity ratios and Lα/Lℓ still remains free from CKs. The pattern of intensity ratios at three excitation energies of elements was well interpreted in terms of on/off of CK transitions (Bambynek et al., 1972; Campbell, 2003) and outer shell electron filling configuration (Scofield, 1973).

Fermi-LAT γ-ray anisotropy and intensity explained by unresolved radio-loud active galactic nuclei

International Nuclear Information System (INIS)

Mauro, Mattia Di; Cuoco, Alessandro; Donato, Fiorenza; Siegal-Gaskins, Jennifer M.

2014-01-01

Radio-loud active galactic nuclei (AGN) are expected to contribute substantially to both the intensity and anisotropy of the isotropic γ-ray background (IGRB). In turn, the measured properties of the IGRB can be used to constrain the characteristics of proposed contributing source classes. We consider individual subclasses of radio-loud AGN, including low-, intermediate-, and high-synchrotron-peaked BL Lacertae objects, flat-spectrum radio quasars, and misaligned AGN. Using updated models of the γ-ray luminosity functions of these populations, we evaluate the energy-dependent contribution of each source class to the intensity and anisotropy of the IGRB. We find that collectively radio-loud AGN can account for the entirety of the IGRB intensity and anisotropy as measured by the Fermi Large Area Telescope (LAT). Misaligned AGN provide the bulk of the measured intensity but a negligible contribution to the anisotropy, while high-synchrotron-peaked BL Lacertae objects provide the dominant contribution to the anisotropy. In anticipation of upcoming measurements with the Fermi-LAT and the forthcoming Cherenkov Telescope Array, we predict the anisotropy in the broader energy range that will be accessible to future observations

Fermi-LAT γ-ray anisotropy and intensity explained by unresolved radio-loud active galactic nuclei

Energy Technology Data Exchange (ETDEWEB)

Mauro, Mattia Di; Cuoco, Alessandro; Donato, Fiorenza [Dipartimento di Fisica, Università di Torino, via P. Giuria 1, Torino, 10125 Italy (Italy); Siegal-Gaskins, Jennifer M., E-mail: mattia.dimauro@to.infn.it, E-mail: alessandro.cuoco@to.infn.it, E-mail: donato@to.infn.it, E-mail: jsg@tapir.caltech.edu [California Institute of Technology, 1200 E. California Blvd., Pasadena, CA, 91125 (United States)

2014-11-01

Radio-loud active galactic nuclei (AGN) are expected to contribute substantially to both the intensity and anisotropy of the isotropic γ-ray background (IGRB). In turn, the measured properties of the IGRB can be used to constrain the characteristics of proposed contributing source classes. We consider individual subclasses of radio-loud AGN, including low-, intermediate-, and high-synchrotron-peaked BL Lacertae objects, flat-spectrum radio quasars, and misaligned AGN. Using updated models of the γ-ray luminosity functions of these populations, we evaluate the energy-dependent contribution of each source class to the intensity and anisotropy of the IGRB. We find that collectively radio-loud AGN can account for the entirety of the IGRB intensity and anisotropy as measured by the Fermi Large Area Telescope (LAT). Misaligned AGN provide the bulk of the measured intensity but a negligible contribution to the anisotropy, while high-synchrotron-peaked BL Lacertae objects provide the dominant contribution to the anisotropy. In anticipation of upcoming measurements with the Fermi-LAT and the forthcoming Cherenkov Telescope Array, we predict the anisotropy in the broader energy range that will be accessible to future observations.

Optimisation of intense X-ray sources of Z-pinch type connected to the high intensity current generator SPHINX

International Nuclear Information System (INIS)

Calamy, H.; Lassalle, F.; Grunenwald, J.; Zucchini, F.

2010-01-01

A new source of intense X-rays in the spectral range of the keV has been designed in the CEA facilities at Gramat (France). This Z-pinch source is based on the implosion of a cylinder of matter that has been ionized by the Lorentz force generated by the injection in the cylinder of an intense current pulse delivered by a HPP (High Pulsed Powers) generator named SPHINX. The cylinder of matter is made up of a few hundreds of thin metal wires (tungsten or aluminium) whose diameter is less than a few tenths of μm. The SPHINX generator is based on the LTD (Linear Transformer Driver) technology. SPHINX stores an energy of 2.2 MJ and delivers a current of 8 MA over a time of 1 μs. SPHINX does not use any technology of time compression, it is a robust, compact machine with reduced maintenance but the price to pay for this simplification is to maintain a high axial homogeneity of the implosion during the initiation phase, it means the pulse time of 1μs. The preliminary experiments that have been performed give the following results: -) for a tungsten cylinder (X ray 1 keV): 28 kJ, 0.6 TW and 25 ns

Solar induced long- and short-term variations of the cosmic ray intensity in the past, and predictions and opportunities for the future

Science.gov (United States)

McCracken, K. G.; McDonald, F. B.; Beer, J.

2009-12-01

The cosmogenic radionuclide data from the past 10,000 years, and the instrumental cosmic ray data since 1936 provide detailed information on the possible consequences of the present long and deep solar minimum. Furthermore, the cosmic ray transport equation has been used to estimate the strength of the interplanetary magnetic field (IMF) throughout the past 10,000 years. This paper presents a series of figures that document the behavior of both the cosmic radiation and the IMF at Earth in the past. In particular, the 11-year cycles in both quantities for the past 600 years are displayed; and estimates given of the cosmic ray spectrum at Earth for situations that history tells us may occur in the near future. Over the longer term, a minimum of the Hallstatt cycle (2200 yr periodicity) of solar activity occurred ~500 years ago and the Sun is now on a steadily rising plane of activity. The historic record shows that the cosmic ray intensity has decreased extremely rapidly after earlier prolonged deep minima and this suggests rapid and large changes in the heliospheric conditions that we may see replicated. The paper will also display data from the deep, isolated solar minimum of 1956 that exhibited unusual low energy cosmic ray fluxes, and a highly anomalous cosmic ray gradient in the inner heliosphere. Paleo-cosmic ray evidence will also be displayed of an episode of intense solar energetic particle (SEP) events in the interval of reduced solar activity, 1892-1900, that may possibly be repeated. If the present long, deep solar minimum is a precursor to a “Grand Minimum” such as the Dalton minimum, it will provide a much improved insight into the spectrum of the cosmic radiation in interstellar space, and to the cosmic ray modulation process in the heliosphere. With this in mind, the paper suggests key measurements, and speculates on experimental conditions that may be markedly different from those encountered in the instrumental era.

Elimination of radical on the x-ray irradiated hydroxyapatite compounds

International Nuclear Information System (INIS)

Ohta, M.; Yasuda, M.; Miyazawa, C.; Okamura, H.; Suzuki, Y.

2002-01-01

We investigate the elimination of radical produced in a human tooth and synthetic calcium-deficient hydroxyapatite compounds after X-ray irradiation. Used samples were enamel and dentine of a human tooth and synthetic calcium-deficient hydroxyapatite (DAp), and stoichiometric hydroxyapatite (HAp). The ESR signal intensities at nearly g = 2 in the samples after X-ray irradiation were proportional to the absorbed dose in the range from 6 to 39 Gy. And these ESR signal intensities of the samples soaked in various ion containing fluids decreased with soaking time. Especially, the decrease in these ESR signal intensities was remarkably large in the samples soaked in Na 2 HPO 4 aqueous solution. This fact suggests that the surface layer of the samples easily dissolves in ion containing fluids

Fluctuations on the X-ray intensity beam using a portable X-ray probe based on {sup 6}LiI(Eu) crystal

Energy Technology Data Exchange (ETDEWEB)

Araujo, Geraldo P.; Oliveira, Arno H. [Universidade Federal de Minas Gerais (PCTN/UFMG), Belo Horizonte, MG (Brazil). Programa de Pos-Graduacao em Ciencias e Tecnicas Nucleares; Carneiro, Andre C.; Carneiro, Clemente J.G.; Milian, Felix M.; Velasco, Fermin G., E-mail: fermin@uesc.b [Universidade Estadual de Santa Cruz (CPqCTR/UESC), Ilheus, BA (Brazil). Centro de Pesquisa em Ciencias e Tecnologias das Radiacoes

2011-07-01

X-rays are produced by accelerating electrons with a high voltage and allowing them to collide with a metal target. This high voltage presents fluctuations that define peak, minimum, and average voltages. Different voltages are applied to the X-ray tube depending on the radiographic applications. A rectifier circuit converts the alternating high voltage to unidirectional high voltage to accelerate electrons in this tube. The fluctuations on the energy in the electron beam depend on the mode of rectification. Both energy of the electrons and X rays intensity fluctuates. A portable probe built with a {sup 6}LiI(Eu) detector coupled to a 10 m light guide and a Hamamatsu photon counting head H9319 was used to measuring X ray intensities. This system is designed to collect up to 10000 counts in intervals of 10 ms to 1 s. Counts were accumulated in time intervals of 10 ms during 10 s. The system starts the count before activating the X-ray apparatus, which is on during a time interval of 100ms. During this period, counts may overflow in consequence high voltage was adjusted to be 40kV, in order to avoid such a problem. For each of these points dose was measured using an ionization chamber. The objectives of this work are to study fluctuations on the X-ray beam and to calibrate the portable probe for measuring radiation doses. Counting rates measured for each 10 ms presented strong variations due to high voltages fluctuations. Both dose and counting rate when correlated with distances between source and detector followed the inverse square law and presented values of R2 near of unit. A calibration curve of the portable system for dose measurements showed also R2 value near of unity. (author)

An experimental measurement of metal multilayer x-ray reflectivity degradation due to intense x-ray flux

International Nuclear Information System (INIS)

Hockaday, M.Y.P.

1987-06-01

The degradation of the x-ray reflection characteristics of metal multilayer Bragg diffractors due to intense x-ray flux was investigated. The Z-pinch plasma produced by PROTO II of Sandia National Laboratories, Albuquerque, New Mexico, was used as the source. The plasma generated total x-ray yields of as much as 40 kJ with up to 15 kJ in the neon hydrogen- and helium-like resonance lines in nominal 20-ns pulses. Molybdenum-carbon, palladium-carbon, and tungsten-carbon metal multilayers were placed at 15 and 150 cm from the plasma center. The multilayers were at nominal angles of 5 0 and 10 0 to diffract the neon resonance lines. The time-integrated x-ray reflection of the metal multilayers was monitored by x-ray film. A fluorescer-fiber optic-visible streak camera detector system was then used to monitor the time-resolved x-ray reflection characteristics of 135 A- 2d tungsten-carbon multilayers. A large specular component in the reflectivity prevented determination of the rocking curve of the multilayer. For a neon implosion onto a vanadium-doped polyacrylic acid foam target shot, detailed modeling was attempted. The spectral flux was determined with data from 5 XRD channels and deconvolved using the code SHAZAM. The observed decay in reflectivity was assumed to correspond to the melting of the first tungsten layer. A ''conduction factor'' of 82 was required to manipulate the heat loading of the first tungsten layer such that the time of melting corresponded to the observed decay. The power at destruction was 141 MW/cm 2 and the integrated energy at destruction was 2.0 J/cm 2 . 82 refs., 66 figs., 10 tabs

The decrease of CO2 emission intensity is decarbonization at national and global levels

International Nuclear Information System (INIS)

Sun, J.W.

2005-01-01

This viewpoint proposes the definition: 'Decarbonization refers to a decrease of CO 2 emission intensity in a trend'. This viewpoint then argues that an analysis of decarbonization at national and global levels based on that definition would lead to the correct calculation of decarbonization

The amount of decrease of the background white noise intensity as a cue for differentiation training.

Science.gov (United States)

Zieliński, K

1981-01-01

The course of differentiation learning, using the conditioned emotional response (CER) method, was investigated in two groups of 16 rats. The discriminative stimuli consisted of decreases in the 80 dB background white noise to either 70 dB or 60 dB. Differentiation learning was more efficient with the larger decrease of background noise intensity as the CS(+) and the smaller decrease as the CS(-) than vice versa.

Spectroscopic study of site selective DNA damage induced by intense soft X-rays

CERN Document Server

Fujii, K

2003-01-01

To investigate the mechanisms of DNA damage induced by direct photon impact, we observed the near edge X-ray absorption fine structures (NEXAFS) of DNA nucleobases using monochromatic synchrotron soft X-rays around nitrogen and oxygen K-shell excitation regions. Each spectrum obtained has unique structure corresponding to pi* excitation of oxygen or nitrogen 1s electron. These aspects open a way of nucleobase-selective photo-excitation in a DNA molecule using high resolution monochromatized soft X-rays. From the analysis of polarization-dependent intensities of the pi* resonance peak, it is clarified that adenine, guanine an uracil form orientated surface structure. Furthermore from the direct measurement of positive ions desorbed from photon irradiated DNA components, it is revealed that the sugar moiety is a fragile site in a DNA molecule. (author)

Wearable device for monitoring momentary presence of intense x-ray and/or ultra-violet radiations

International Nuclear Information System (INIS)

Shriner, W.

1981-01-01

A credit-card-size clear-plastic-encased device can be worn or carried by a person to warn him of the momentary presence of dangerous intensities of ultra-violet and/or x-ray radiations. A base lamina (e.g. of cardboard) is coated with a material (e.g. zinc-cadmium sulfide or lead-barium sulfate) which fluoresces under such radiations. Numerals, letters, words or symbols are printed over the fluorescent coat with a material inhibitory to said radiations so that a warning message in dark print will appear on a light background when dangerous intensities of said radiations are present. An x-ray-warning area is covered with an ultra-violet absorbing screen so that said area will glow only under x-rays (Which rays will also activate the remaining ultra-violet-responsive area). The colors of the laminas and the coats are so selected that the messages are not visible when dangerous radiations are not present. If desired, only the message can be printed with fluorescent material so as to glow on a darker background. Optionally, step-layer attenuation devices can be added to indicate degrees of radiation; and reflecting surfaces can underlie the fluorescent coat to increase efficiency and/or sensitively

Study on 2015 June 22 Forbush decrease with the muon telescope in Antarctic

OpenAIRE

Huang, De-Hong; Hu, Hong-Qiao; Zhang, Ji-Long; Lu, Hong; Zhang, Da-Li; Xue, Bin-Shen; Lu, Jing-Tian

2017-01-01

By the end of 2014, a cosmic ray muon telescope was installed at Zhongshan Station in Antarctic and has been continuously collecting data since then. It is the first surface muon telescope to be built in Antarctic. In June 2015, five CMEs were ejected towards the Earth initiating a big large Forbush decrease (FD) event. We conduct a comprehensive study of the galactic cosmic ray intensity fluctuations during the FD using the data from cosmic ray detectors of multiple stations (Zhongshan, McMu...

Neutron beam design for low intensity neutron and gamma-ray radioscopy using small neutron sources

CERN Document Server

Matsumoto, T

2003-01-01

Two small neutron sources of sup 2 sup 5 sup 2 Cf and sup 2 sup 4 sup 1 Am-Be radioisotopes were used for design of neutron beams applicable to low intensity neutron and gamma ray radioscopy (LINGR). In the design, Monte Carlo code (MCNP) was employed to generate neutron and gamma ray beams suited to LINGR. With a view to variable neutron spectrum and neutron intensity, various arrangements were first examined, and neutron-filter, gamma-ray shield and beam collimator were verified. Monte Carlo calculations indicated that with a suitable filter-shield-collimator arrangement, thermal neutron beam of 3,900 ncm sup - sup 2 s sup - sup 1 with neutron/gamma ratio of 7x10 sup 7 , and 25 ncm sup - sup 2 s sup - sup 1 with very large neutron/gamma ratio, respectively, could be produced by using sup 2 sup 5 sup 2 Cf(122 mu g) and a sup 2 sup 4 sup 1 Am-Be(37GBq)radioisotopes at the irradiation port of 35 cm from the neutron sources.

Energy dependence of photon-induced L-shell x-ray intensity ratios in some high-Z elements

Energy Technology Data Exchange (ETDEWEB)

Shatendra, K; Allawadhi, K L; Sood, B S [Punjabi Univ., Patiala (India). Nuclear Science Labs.

1983-12-14

The L-shell x-ray intensity ratios in Au, Pb, Th and U at various photon energies have been measured and their energy dependence is studied. A comparison of the experimental values is made with those calculated using the x-ray emission rates and subshell photoelectric cross sections, subshell fluorescence yields and Coster-Kronig transition probabilities and fairly good agreement is observed.

Comparison of γ-ray intensity distribution around Hira fault with spatial pattern of major and/or sub fault system

International Nuclear Information System (INIS)

Nakanishi, Tatsuya; Mino, Kazuo; Ogasawara, Hiroshi; Katsura, Ikuo

1999-01-01

Major active faults generally consist of systems of a number of fractures with various dimensions, and contain a lot of ground water. Rn gas, moving with underground water, tends to accumulate along faults and emit γ-ray while it decays down to Pb through Bi. Therefore, it has been shown by a number of works that γ-ray intensity is generally high near the core of the major active fault and the γ-ray survey is one of the effective methods to look for the core of the major active fault. However, around the area near the tips of faults, a number of complicated sub-fault systems and the corresponding complicated geological structures are often seen and it has not been investigated well about what can be the relationship between the intensity distribution of γ-ray and the fault systems. In order to investigate the relationship in an area near the tips of major faults well, therefore, we carried out the γ-ray survey at about 1,100 sites in an area of about 2 km x 2 km that has the tips of the two major right lateral faults with significant thrusting components. We also investigated the lineaments by using the topographic map published in 1895 when artificial construction was seldom seen in the area and we can easily see the natural topography. In addition, we carried out the γ-ray survey in an area far from the fault tip to compare with the results in the area with the fault tips. Then: (1) we reconfirmed that in the case of the middle of the major active fault, γ-ray intensity is high in the limited area just adjacent to the core of the fault. (2) However, we found that in the case of the tip of the major active fault, high γ-ray intensity is seen in much wider area with clear lineaments that is inferred to be developed associated with the movement of the major faults. (author)

Sustained, Low?Intensity Exercise Achieved by a Dynamic Feeding System Decreases Body Fat in Ponies

OpenAIRE

de Laat, M.A.; Hampson, B.A.; Sillence, M.N.; Pollitt, C.C.

2016-01-01

Background Obesity in horses is increasing in prevalence and can be associated with insulin insensitivity and laminitis. Current treatment strategies for obesity include dietary restriction and exercise. However, whether exercise alone is effective for decreasing body fat is uncertain. Hypothesis Our hypothesis was that twice daily use of a dynamic feeding system for 3 months would induce sustained, low?intensity exercise thereby decreasing adiposity and improving insulin sensitivity (SI). An...

X-ray intensity and source size characterizations for the 25 kV upgraded Manson source at Sandia National Laboratories

Energy Technology Data Exchange (ETDEWEB)

Loisel, G., E-mail: gploise@sandia.gov; Lake, P.; Gard, P.; Dunham, G.; Nielsen-Weber, L.; Wu, M. [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); Norris, E. [Missouri University of Science and Technology, Rolla, Missouri 65409 (United States)

2016-11-15

At Sandia National Laboratories, the x-ray generator Manson source model 5 was upgraded from 10 to 25 kV. The purpose of the upgrade is to drive higher characteristics photon energies with higher throughput. In this work we present characterization studies for the source size and the x-ray intensity when varying the source voltage for a series of K-, L-, and M-shell lines emitted from Al, Y, and Au elements composing the anode. We used a 2-pinhole camera to measure the source size and an energy dispersive detector to monitor the spectral content and intensity of the x-ray source. As the voltage increases, the source size is significantly reduced and line intensity is increased for the three materials. We can take advantage of the smaller source size and higher source throughput to effectively calibrate the suite of Z Pulsed Power Facility crystal spectrometers.

X-ray intensity and source size characterizations for the 25 kV upgraded Manson source at Sandia National Laboratories.

Science.gov (United States)

Loisel, G; Lake, P; Gard, P; Dunham, G; Nielsen-Weber, L; Wu, M; Norris, E

2016-11-01

At Sandia National Laboratories, the x-ray generator Manson source model 5 was upgraded from 10 to 25 kV. The purpose of the upgrade is to drive higher characteristics photon energies with higher throughput. In this work we present characterization studies for the source size and the x-ray intensity when varying the source voltage for a series of K-, L-, and M-shell lines emitted from Al, Y, and Au elements composing the anode. We used a 2-pinhole camera to measure the source size and an energy dispersive detector to monitor the spectral content and intensity of the x-ray source. As the voltage increases, the source size is significantly reduced and line intensity is increased for the three materials. We can take advantage of the smaller source size and higher source throughput to effectively calibrate the suite of Z Pulsed Power Facility crystal spectrometers.

Investigations of Forbush decreases in the PAMELA experiment

Science.gov (United States)

Lagoida, I. A.; Voronov, S. A.; Mikhailov, V. V.

2017-01-01

A phenomenon in cosmic ray physics now called Forbush decrease (FD), or Forbush effect was discovered by S. Forbush in 1937 [1], it is a sudden decrease of galactic cosmic ray (GCR) intensity near the Earth. However, despite of the long term investigations the nature of this phenomenon is still not completely understood. Today this effect is studied mostly by the neutron monitors and muon hodoscopes, which are located on the Earth’s surface. But these monitors can detect only products of GCR interaction with the Earth atmosphere. Satellite detectors allow to obtain more accurate information about the characteristics of FD. Examples of FDs registered by the PAMELA telescope and observed with Oulu neutron monitor are presented. About 10 events with amplitude more than 3% have been registered from 2006 till 2016 with the PAMELA experiment.

Decreasing of the detection limit for gamma-ray Spectrometry with the influence of sample treatment

International Nuclear Information System (INIS)

Karami, M.; Sadighzadeh, A.; Asgharizadeh, F.; Sardari, D.; Tavassoli, A.; Arbabi, A.; Hochaghani, O.

2009-01-01

Full text: In this study the ash method has been applied for environmental sample treatment in order to decrease of the detection limit in gamma-ray spectrometry for low level radioactivity measurements. Detection limit in gamma ray spectrometry is the smallest expectation value of the net counting rate that can be detected on given probabilities. The environmental test samples have been changed into ash using a suitable oven. The heating were made under controlled temperature to avoid the escape of some radionuclides such as radiocaesium. The ash samples were measured by high resolution gamma-ray spectrometry system. (author)

The intermediate polar GK Persei: An unstable relation of the X-ray and the optical intensities in a series of outbursts

Science.gov (United States)

Šimon, V.

2015-03-01

Context. GK Per is an intermediate polar that has been displaying dwarf nova outbursts since the middle of the twentieth century. Aims: I analyzed a series of such outbursts in the optical and X-ray bands. I pay attention to the relation of intensities of the optical and X-ray emissions, and its reproducibility in a series of these consecutive outbursts. Methods: This analysis uses the data from the BAT/Swift, ASM/RXTE, AAVSO, and AFOEV databases. It investigates the relation of the time evolution of the profiles of outbursts in the individual bands (hard X-ray, medium/hard X-ray, and optical). Results: This analysis shows that the X-ray intensity steeply rises only in the start of the optical outburst and steeply declines only when the optical outburst comes to its end. However, the 1.5-50 keV band intensity saturates and balances on a plateau during the outburst. (The longer the outburst, the longer its plateau.) The peak X-ray intensities of this series display a significantly narrower range than the optical ones (a factor of about two versus a factor of about eight). This implies a discrepancy between the mass flow through the disk and the production of the X-ray emission via bremsstrahlung at the polar caps of the white dwarf. This discrepancy is the largest in the time of the peak optical intensity when the whole disk (or at least its inner part) is in the hot state and the flow of matter through the disk is the greatest. This study shows that a series of outbursts constitutes more general properties of this discrepancy. I argue that the saturation of the X-ray luminosity in outburst cannot be caused by a dominant increase in X-ray absorption. In the interpretation, large structural changes of the accreting regions at the magnetic poles of the white dwarf occur during the outburst. A buried shock proposed by some authors for polars is also promising for explaining the X-ray light curves of outbursts of GK Per. This research made use of the BAT/Swift, ASM

Results of cosmic ray intensity measurements by the ''Luna-19'' space probe

International Nuclear Information System (INIS)

Chuchkov, E.A.; Lyubimov, G.P.; Myagchenkova, O.G.; Novichkova, A.D.; Pereslegina, N.V.; Kontor, N.N.; Nikolaev, A.G.

1975-01-01

Results are reviewed of measurements of low energy cosmic-ray characteristics obtained by means of the equipment installed on the ''Luna-19'' space station over the period from 28 November, 1971 to August 20, 1972. Proton fluxes with the energy of 1-5, 5-10, 10-40 MeV were mainly detected. A brief analysis both of individual events in cosmic rays and the general variation of intensity over the period from 1971 to 1972 is presented. Solar and geophysical data are used for the analysis. It is demonstrated that the period of the ''Luna-19'' operation corresponded to the secondary (anomalous) maximum on the decay of the solar activity in the 20th cycle. Assumptions concerning the nature of this maximum are formulated

Cosmic ray modulation and merged interaction regions

International Nuclear Information System (INIS)

Burlaga, L.F.; Goldstein, M.L.; Mcdonald, F.B.

1985-01-01

Beyond several AU, interactions among shocks and streams give rise to merged interaction regions in which the magnetic field is turbulent. The integral intensity of . 75 MeV/Nuc cosmic rays at Voyager is generally observed to decrease when a merged interaction region moves past the spacecraft and to increase during the passage of a rarefaction region. When the separation between interaction regions is relatively large, the cosmic ray intensity tends to increase on a scale of a few months. This was the case at Voyager 1 from July 1, 1983 to May 1, 1984, when the spacecraft moved from 16.7 to 19.6 AU. Changes in cosmic ray intensity were related to the magnetic field strength in a simple way. It is estimated that the diffusion coefficient in merged interaction regions at this distance is similar to 0.6 x 10 to the 22nd power sq cm/s

Numerical modeling of the 22-year variation of the cosmic ray intensity and anisotropy

International Nuclear Information System (INIS)

Kadokura, A.; Nishida, A.

1986-01-01

We have solved the two-dimensional time-dependent diffusion-convection equation numerically to obtain the distribution and anisotropy of cosmic rays in the heliosphere. We have assumed that the parallel and perpendicular mean free paths are proportional to the particle Larmor radius, and we have treated each proportionality constant (a,b) as a parameter. We have found that the set (a,b) = (4,2) gives the steady state solution compatible with observations on the intensity and the solar diurnal anisotropy of cosmic rays in 0.5- to 10-GeV range as obtained at the earth. This set of (a,b) corresponds to the ratio of the diffusion coefficients D/sub parallel//D/sub perpendicular/ = 10. In our solution the intensity for the (pre-1980) interplanetary magnetic field (IMF) state where the solar magnetic dipole and the angular velocity vector are parallel is higher than for the (post-1980) state where they are antiparallel, while the phase of the diurnal anisotropy is about 15 hours for the parallel state and about 18 hours for the antiparallel state. We have also reproduced the observed small radial gradient for each IMF state. We discuss the nature of the solution in order to understand the effect of the density gradient drift motion on the cosmic ray distribution

Development of a software for reconstruction of X-ray fluorescence intensity maps

International Nuclear Information System (INIS)

Almeida, Andre Pereira de; Braz, Delson; Mota, Carla Lemos; Oliveira, Luis Fernando de; Barroso, Regina Cely; Pinto, Nivia Graciele Villela; Cardoso, Simone Coutinho; Moreira, Silvana

2009-01-01

The technique of X-ray fluorescence (XRF) using SR microbeams is a powerful analysis tool for studying elemental composition in several samples. One application of this technique is the analysis done through the mapping of chemical elements forming a matrix of data. The aim of this work is the presentation of the program MapXRF, an in-house software designed to optimize the processing and mapping of fluorescence intensities data. This program uses spectra generated by QXAS as input data and separates the intensities of each chemical element found in the fluorescence spectra in files themselves. From these files, the program generates the intensity maps that can be visualized in any program of treatment of images. The proposed software was tested using fluorescence data obtained in the XRF beamline of XRF at Synchrotron Light National Laboratory (LNLS), Brazil. Automatic 2D scans were performed and element distribution maps were obtained in the form of a matrix of data. (author)

Development of a software for reconstruction of X-ray fluorescence intensity maps

Energy Technology Data Exchange (ETDEWEB)

Almeida, Andre Pereira de; Braz, Delson; Mota, Carla Lemos, E-mail: apalmeid@gmail.co, E-mail: delson@lin.ufrj.b, E-mail: clemos@con.ufrj.b [Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear; Oliveira, Luis Fernando de; Barroso, Regina Cely; Pinto, Nivia Graciele Villela, E-mail: cely@uerj.b, E-mail: lfolive@uerj.b, E-mail: nitatag@gmail.co [Universidade do Estado do Rio de Janeiro (UERJ), Rio de Janeiro, RJ (Brazil). Inst. de Fisica; Cardoso, Simone Coutinho, E-mail: simone@if.ufrj.b [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Inst. de Fisica; Moreira, Silvana, E-mail: silvana@fec.unicamp.b [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Faculdade de Engenharia Civil, Arquitetura e Urbanismo

2009-07-01

The technique of X-ray fluorescence (XRF) using SR microbeams is a powerful analysis tool for studying elemental composition in several samples. One application of this technique is the analysis done through the mapping of chemical elements forming a matrix of data. The aim of this work is the presentation of the program MapXRF, an in-house software designed to optimize the processing and mapping of fluorescence intensities data. This program uses spectra generated by QXAS as input data and separates the intensities of each chemical element found in the fluorescence spectra in files themselves. From these files, the program generates the intensity maps that can be visualized in any program of treatment of images. The proposed software was tested using fluorescence data obtained in the XRF beamline of XRF at Synchrotron Light National Laboratory (LNLS), Brazil. Automatic 2D scans were performed and element distribution maps were obtained in the form of a matrix of data. (author)

Cosmic ray variations of solar origin in relation to human physiological state during the December 2006 solar extreme events

Science.gov (United States)

Papailiou, M.; Mavromichalaki, H.; Vassilaki, A.; Kelesidis, K. M.; Mertzanos, G. A.; Petropoulos, B.

2009-02-01

There is an increasing amount of evidence linking biological effects to solar and geomagnetic disturbances. A series of studies is published referring to the changes in human physiological responses at different levels of geomagnetic activity. In this study, the possible relation between the daily variations of cosmic ray intensity, measured by the Neutron Monitor at the Cosmic Ray Station of the University of Athens (http://cosray.phys.uoa.gr) and the average daily and hourly heart rate variations of persons, with no symptoms or hospital admission, monitored by Holter electrocardiogram, is considered. This work refers to a group of persons admitted to the cardiological clinic of the KAT Hospital in Athens during the time period from 4th to 24th December 2006 that is characterized by extreme solar and geomagnetic activity. A series of Forbush decreases started on 6th December and lasted until the end of the month and a great solar proton event causing a Ground Level Enhancement (GLE) of the cosmic ray intensity on 13th December occurred. A sudden decrease of the cosmic ray intensity on 15th December, when a geomagnetic storm was registered, was also recorded in Athens Neutron Monitor station (cut-off rigidity 8.53 GV) with amplitude of 4%. It is noticed that during geomagnetically quiet days the heart rate and the cosmic ray intensity variations are positively correlated. When intense cosmic ray variations, like Forbush decreases and relativistic proton events produced by strong solar phenomena occur, cosmic ray intensity and heart rate get minimum values and their variations, also, coincide. During these events the correlation coefficient of these two parameters changes and follows the behavior of the cosmic ray intensity variations. This is only a small part of an extended investigation, which has begun using data from the year 2002 and is still in progress.

Determination of the X-ray mass absorption coefficient by measurement of the intensity of AgKα Compton scattered radiation

International Nuclear Information System (INIS)

Franzini, M.; Leoni, L.; Saitta, M.

1976-01-01

By utilizing a reflection geometry, an accurate mass absorption coefficient of a sample can be determined by measuring the Ag Kα Compton intensity. Intensities of Ag Kα Compton scattered radiation have been collected by using either the usual reflection geometry of a Philips PW 1450 automatic x-ray spectrometer or a more refined reflection geometry, achieved on a Philips PW 1540/10A manual x-ray spectrometer. The experimental results have shown that the relationship between the Ag Kα Compton intensity and the mass absorption is a logarithmic function. The experimental results are not in agreement with those reported in literature, but a theoretical explanation to account for this fact has not been achieved as yet. (author)

Analysis of distribution of PSL intensity recorded in imaging plate

International Nuclear Information System (INIS)

Oda, Keiji; Tsukahara, Kazutaka; Tada, Hidenori; Yamauchi, Tomoya

2006-01-01

Supplementary experiments and theoretical consideration have been performed about a new method for particle identification with an imaging plate, which was proposed in the previous paper. The imaging plate was exposed to 137 Cs γ-rays, 2 MeV- protons accelerated by a tandem Van de Graaff, X-rays emitted from a tube operated under the condition of 20-70 kV, as well as α- and β-rays. The frequency distribution in PSL intensity in a pixel of 100μm x 100μm was measured and the standard deviation was obtained by fitting to a Gaussian. It was confirmed that the relative standard deviation decreased with the average PSL intensity for every radiation species and that the curves were roughly divided into four groups of α-rays, protons, β-rays and photons. In the second step, these data were analyzed by plotting the square of the relative standard deviation against the average PSL intensity in full-log scale, where the relation should be expressed by a straight line with an slope of -1 provided that the deviation could be dominated only by statistical fluctuation. The data for α- and β-rays deviated from a straight line and approached to each saturated value as the average PSL intensity increased. This saturation was considered to be caused by inhomogeneity in the source intensity. It was also out that the value of interception on full-log plot would have important information about PSL reading efficiency, one of characteristic parameters of imaging plate. (author)

The fluid dynamics of microjet explosions caused by extremely intense X-ray pulses

Science.gov (United States)

Stan, Claudiu; Laksmono, Hartawan; Sierra, Raymond; Milathianaki, Despina; Koglin, Jason; Messerschmidt, Marc; Williams, Garth; Demirci, Hasan; Botha, Sabine; Nass, Karol; Stone, Howard; Schlichting, Ilme; Shoeman, Robert; Boutet, Sebastien

2014-11-01

Femtosecond X-ray scattering experiments at free-electron laser facilities typically requires liquid jet delivery methods to bring samples to the region of interaction with X-rays. We have imaged optically the damage process in water microjets due to intense hard X-ray pulses at the Linac Coherent Light Source (LCLS), using time-resolved imaging techniques to record movies at rates up to half a billion frames per second. For pulse energies larger than a few percent of the maximum pulse energy available at LCLS, the X-rays deposit energies much larger than the latent heat of vaporization in water, and induce a phase explosion that opens a gap in the jet. The LCLS pulses last a few tens of femtoseconds, but the full evolution of the broken jet is orders of magnitude slower - typically in the microsecond range - due to complex fluid dynamics processes triggered by the phase explosion. Although the explosion results in a complex sequence of phenomena, they lead to an approximately self-similar flow of the liquid in the jet.

Quantitative x-ray absorption imaging with a broadband source: application to high-intensity discharge lamps

Energy Technology Data Exchange (ETDEWEB)

Curry, J J [National Institute of Standards and Technology, Gaithersburg, MD 20899-8422 (United States)], E-mail: jjcurry@nist.gov

2008-07-21

The case of x-ray absorption imaging in which the x-ray source is broadband and the detector does not provide spectral resolution is analysed. The specific motivation is observation of the Hg vapour distribution in high-intensity discharge (HID) lamps. When absorption by the vapour is small, the problem can be couched accurately in terms of a mean absorption cross section averaged over the x-ray spectral distribution, weighted by the energy-dependent response of the detector. The method is tested against a Au foil standard and then applied to Hg. The mean absorption cross section for Hg is calculated for a Ag-anode x-ray tube at accelerating voltages of 25, 30 and 35 kV, and for HIDs in fused silica or polycrystalline alumina arc tubes.

Rotation of the Earth, solar activity and cosmic ray intensity

Energy Technology Data Exchange (ETDEWEB)

Barlyaeva, T.; Bard, E. [Aix-Marseille Univ., CNRS, IRD, Aix-en-Provence (France). CEREGE, College de France; Abarca-del-Rio, R. [Universidad de Concepcion (UDEC) (Chile). Dept. de Geofisica (DGEO)

2014-10-01

We analyse phase lags between the 11-year variations of three records: the semi-annual oscillation of the length of day (LOD), the solar activity (SA) and the cosmic ray intensity (CRI). The analysis was done for solar cycles 20-23. Observed relationships between LOD, CRI and SA are discussed separately for even and odd solar cycles. Phase lags were calculated using different methods (comparison of maximal points of cycles, maximal correlation coefficient, line of synchronization of cross-recurrence plots). We have found different phase lags between SA and CRI for even and odd solar cycles, confirming previous studies. The evolution of phase lags between SA and LOD as well as between CRI and LOD shows a positive trend with additional variations of phase lag values. For solar cycle 20, phase lags between SA and CRI, between SA and LOD, and between CRI and LOD were found to be negative. Overall, our study suggests that, if anything, the length of day could be influenced by solar irradiance rather than by cosmic rays.

Intense gamma-ray lines from hidden vector dark matter decay

International Nuclear Information System (INIS)

Arina, Chiara; Hambye, Thomas

2009-12-01

Scenarios with hidden, spontaneously broken, non-abelian gauge groups contain a natural dark matter candidate, the hidden vector, whose longevity is due to an accidental custodial symmetry in the renormalizable Lagrangian. Nevertheless, non-renormalizable dimension six operators break the custodial symmetry and induce the decay of the dark matter particle at cosmological times. We discuss in this paper the cosmic ray signatures of this scenario and we show that the decay of hidden vector dark matter particles generically produce an intense gamma ray line which could be observed by the Fermi-LAT experiment, if the scale of custodial symmetry breaking is close to the Grand Unification scale. This gamma line proceeds directly from a tree level dark matter 2-body decay in association with a Higgs boson. Within this model we also perform a determination of the relic density constraints taking into account the dark matter annihilation processes with one dark matter particle in the final state. The corresponding direct detection rates can be easily of order the current experimental sensitivities. (orig.)

Intense gamma-ray lines from hidden vector dark matter decay

Energy Technology Data Exchange (ETDEWEB)

Arina, Chiara; Hambye, Thomas [Universite Libre de Bruxelles (Belgium). Service de Physique Theorique; Ibarra, Alejandro [Technische Univ. Muenchen, Garching (Germany). Physik-Department; Weniger, Christoph [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

2009-12-15

Scenarios with hidden, spontaneously broken, non-abelian gauge groups contain a natural dark matter candidate, the hidden vector, whose longevity is due to an accidental custodial symmetry in the renormalizable Lagrangian. Nevertheless, non-renormalizable dimension six operators break the custodial symmetry and induce the decay of the dark matter particle at cosmological times. We discuss in this paper the cosmic ray signatures of this scenario and we show that the decay of hidden vector dark matter particles generically produce an intense gamma ray line which could be observed by the Fermi-LAT experiment, if the scale of custodial symmetry breaking is close to the Grand Unification scale. This gamma line proceeds directly from a tree level dark matter 2-body decay in association with a Higgs boson. Within this model we also perform a determination of the relic density constraints taking into account the dark matter annihilation processes with one dark matter particle in the final state. The corresponding direct detection rates can be easily of order the current experimental sensitivities. (orig.)

Rotation of the Earth, solar activity and cosmic ray intensity

International Nuclear Information System (INIS)

Barlyaeva, T.; Bard, E.

2014-01-01

We analyse phase lags between the 11-year variations of three records: the semi-annual oscillation of the length of day (LOD), the solar activity (SA) and the cosmic ray intensity (CRI). The analysis was done for solar cycles 20-23. Observed relationships between LOD, CRI and SA are discussed separately for even and odd solar cycles. Phase lags were calculated using different methods (comparison of maximal points of cycles, maximal correlation coefficient, line of synchronization of cross-recurrence plots). We have found different phase lags between SA and CRI for even and odd solar cycles, confirming previous studies. The evolution of phase lags between SA and LOD as well as between CRI and LOD shows a positive trend with additional variations of phase lag values. For solar cycle 20, phase lags between SA and CRI, between SA and LOD, and between CRI and LOD were found to be negative. Overall, our study suggests that, if anything, the length of day could be influenced by solar irradiance rather than by cosmic rays.

Intense gamma-ray lines from hidden vector dark matter decay

International Nuclear Information System (INIS)

Arina, Chiara; Hambye, Thomas; Ibarra, Alejandro; Weniger, Christoph

2010-01-01

Scenarios with hidden, spontaneously broken, non-abelian gauge groups contain a natural dark matter candidate, the hidden vector, whose longevity is due to an accidental custodial symmetry in the renormalizable Lagrangian. Nevertheless, non-renormalizable dimension six operators break the custodial symmetry and induce the decay of the dark matter particle at cosmological times. We discuss in this paper the cosmic ray signatures of this scenario and we show that the decay of hidden vector dark matter particles generically produce an intense gamma ray line which could be observed by the Fermi-LAT experiment, if the scale of custodial symmetry breaking is close to the Grand Unification scale. This gamma line proceeds directly from a tree level dark matter 2-body decay in association with a Higgs boson. Within this model we also perform a determination of the relic density constraints taking into account the dark matter annihilation processes with one dark matter particle in the final state. The corresponding direct detection rates can be easily of order the current experimental sensitivities

Decrease in the cortical intensity on T2-weighted magnetic resonance imaging with aging in normal subjects

International Nuclear Information System (INIS)

Imon, Yukari; Murata, Yoshio; Kajima, Toshio; Nakamura, Shigenobu; Yamaguchi, Shinya

1997-01-01

We reported previously that Low T 2 intensity areas (LIAs) are more common in patients with central nervous system (CNS) diseases than in those with no such diseases, and that the occurrence of LIAs increases with aging. To determine a relationship between the intensity changes and aging, we investigated the intensity of the cerebral cortex in 26 normal Japanese individuals. Measurements of brain MRIs were performed with a Signa Advantage apparatus at 1.5 tesla. T 2 -weighted images were obtained using the spin-echo pulse sequences. On our laboratory console, we measured signal intensities in the regions of interest in the prefrontal, motor, sensory, parietal, temporal, or occipital cortex, and in the frontal white matter. To remove the effect of the system gain settings on signal intensity, that of cerebrospinal fluid was used as reference according to the method of Pujol et al. The average intensity in the temporal and prefrontal cortices was the highest, followed in order by the parietal, sensory, motor, and occipital cortices. The intensity in the temporal and parietal cortices decreased significantly with aging, and that in the motor and sensory cortices had a tendency to decrease with aging. The intensity in the motor and sensory cortices of the elderly subjects and that in the occipital cortex throughout all ages were lower than that in the prefrontal white matter, which would result in the appearance of LIAs. The average intensity of each cerebral cortex was inversely related to the non-heme iron content previously reported. It is likely that the difference in intensity among the cortices reflects variations of the non-heme iron content, and that the change in intensity with aging could be due to the increase in such cortical senile changes as that of microglia, astroglia, and senile plaques, which contain iron or iron-related proteins. The temporal cortex is most susceptible to senile changes. (K.H.)

Department of Cosmic Ray Physics: Overview

International Nuclear Information System (INIS)

Szabelski, J.

2001-01-01

Full text: The Department of Cosmic Ray Physics in Lodz is involved in basic research in the area of high-energy physics and cosmic ray physics related to: Experimental and phenomenological studies of Extensive Air Showers induced by cosmic ray particles. Studies of ultra-high energy (above 10 19 eV) cosmic rays: determination of energy and primary particle mass composition. Studies of asymptotic properties of hadronic interactions based on the analysis of cosmic ray propagation through the atmosphere. Studies of mass composition of cosmic rays in the energy range 10 15 -10 17 eV. Registration of cosmic ray intensity variation correlated with solar activity. Theoretical and experimental studies of Extensive Air Shower properties are performed mostly based on the results obtained by the Lodz Extensive Air Shower Array. We have noticed unexplainable delayed signals registered about 500-900 microseconds after the main EAS pulse. We prepared hardware for further experimental study of this effect. In September we have started registration of 5 GeV muon flux with the underground muon telescope. We registered 3 decreases of muon intensity correlated with Forbush decreases registered at lower energies. Variations of primary cosmic ray of energies up to about 100 GeV were responsible for our registrations. These set the upper limits for geometrical size of geomagnetic disturbances in interplanetary space. In construction and data interpretation of cosmic ray experiments, the Lodz group collaborates with many foreign institutes and laboratories: Forschungszentrum in Karlsruhe (Germany), College de France, Institute for Nuclear Studies of the Russian Academy of Sciences and Uppsala University (Sweden). We have organised (together with the Physics Department of the University of Lodz) the 17 th European Cosmic Ray Symposium (24-?8 July 2000) in which about 150 physicists participated (about 100 from abroad). (author)

X-ray and DSC studies on the melt-recrystallization process of poly(butylene naphthalate)

International Nuclear Information System (INIS)

Yasuniwa, Munehisa; Tsubakihara, Shinsuke; Fujioka, Takashi

2003-01-01

Melt-recrystallization in the heating process of poly(butylene naphthalate) (PBN) was studied with X-ray analysis and differential scanning calorimetry (DSC). DSC melting curve of an isothermally crystallized sample showed double endothermic peaks. With increasing the temperature, wide-angle X-ray diffraction (WAXD) patterns of the sample were obtained successively. Crystal structure did not change during the double melting process. The X-ray diffraction intensity decreased gradually in the temperature region up to about 200 deg. C, and then increased distinctly before steep decrease due to the final melting. This increase is interpreted as a proof of recrystallization. The temperature derivative curve of the diffraction intensity was similar to the DSC melting curve

Asymmetrically cut crystal pair as x-ray magnifier for imaging at high intensity laser facilities

Energy Technology Data Exchange (ETDEWEB)

Szabo, C. I.; Feldman, U. [Artep Inc., 2922 Excelsior Spring Circle, Ellicott City, Maryland 21042 (United States); Seely, J. F. [Space Science Division, Naval Research Laboratory, Washington, DC 20375-5352 (United States); Curry, J. J.; Hudson, L. T.; Henins, A. [National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States)

2010-10-15

The potential of an x-ray magnifier prepared from a pair of asymmetrically cut crystals is studied to explore high energy x-ray imaging capabilities at high intensity laser facilities. OMEGA-EP and NIF when irradiating mid and high Z targets can be a source of high-energy x-rays whose production mechanisms and use as backlighters are a subject of active research. This paper studies the properties and potential of existing asymmetric cut crystal pairs from the National Institute of Standards and Technology (NIST) built in a new enclosure for imaging x-ray sources. The technique of the x-ray magnifier has been described previously. This new approach is aimed to find a design that could be used at laser facilities by magnifying the x-ray source into a screen far away from the target chamber center, with fixed magnification defined by the crystals' lattice spacing and the asymmetry angles. The magnified image is monochromatic and the imaging wavelength is set by crystal asymmetry and incidence angles. First laboratory results are presented and discussed.

Determination of crystal structures with large known fragments directly from measured X-ray powder diffraction intensities

International Nuclear Information System (INIS)

Rius, J.; Miravitlles, C.

1988-01-01

A strategy for the determination of crystal structures with large known fragments directly from measured X-ray powder diffraction intensities is presented. It is based on the automated full-symmetry Patterson search method described by Rius and Miravitlles where the Fourier coefficients of the observed Patterson function are modified to allow the use of powder diffraction intensity data. Its application to two structures, one with simulated and one with experimental data, is shown. (orig.)

Pyroelectric composite for detection of X-ray intensity

International Nuclear Information System (INIS)

Sakamoto, Walter Katsumi; Estevam, Giuliano Pierre; Carvalho, Aparecido Augusto de; Pontes, Wesley; Paula, Mauro Henrique de

2010-01-01

Composite material obtained with modified lead titanate (Pz34) ferroelectric ceramic and polyether-ether-ketone (PEEK) polymer matrix was used as sensitive component to measure X-ray intensity in a novel detection system. The sensing element works as a thermal transducer, converting a non-quantified thermal flux into an output measurable quantity of electrical voltage. The samples were obtained up to 60 vol.% of ceramic, by hot pressing the mixture of Pz34 and PEEK powders at 368 deg C and applying 12 MPa pressure for 2.0 h. The sensor response varies from 2.70 V to 0.80 V in the energy fluence rate range of 6.30 to 37.20 W/m 2 . The absorbed incident energy was analyzed as a function of the ionizing energy. Furthermore, by measuring the pyroelectric activity of the composite film it was observed that there is no degradation of the sensor after the irradiation. (author)

Emergence of Uranium as a Distinct Metal Center for Building Intrinsic X-ray Scintillators.

Science.gov (United States)

Wang, Yaxing; Yin, Xuemiao; Liu, Wei; Xie, Jian; Chen, Junfeng; Silver, Mark A; Sheng, Daopeng; Chen, Lanhua; Diwu, Juan; Liu, Ning; Chai, Zhifang; Albrecht-Schmitt, Thomas E; Wang, Shuao

2018-06-25

The combination of high atomic number and high oxidation state in U VI materials gives rise to both high X-ray attenuation efficiency and intense green luminescence originating from ligand-to-metal charge transfer. These two features suggest that U VI materials might act as superior X-ray scintillators, but this postulate has remained substantially untested. Now the first observation of intense X-ray scintillation in a uranyl-organic framework (SCU-9) that is observable by the naked eye is reported. Combining the advantage in minimizing the non-radiative relaxation during the X-ray excitation process over those of inorganic salts of uranium, SCU-9 exhibits a very efficient X-ray to green light luminescence conversion. The luminescence intensity shows an essentially linear correlation with the received X-ray intensity, and is comparable with that of commercially available CsI:Tl. SCU-9 possesses an improved X-ray attenuation efficiency (E>20 keV) as well as enhanced radiation resistance and decreased hygroscopy compared to CsI:Tl. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Time dependence of X-ray polarizability of a crystal induced by an intense femtosecond X-ray pulse

Directory of Open Access Journals (Sweden)

A. Leonov

2014-11-01

Full Text Available The time evolution of the electron density and the resulting time dependence of Fourier components of the X-ray polarizability of a crystal irradiated by highly intense femtosecond pulses of an X-ray free-electron laser (XFEL is investigated theoretically on the basis of rate equations for bound electrons and the Boltzmann equation for the kinetics of the unbound electron gas. The photoionization, Auger process, electron-impact ionization, electron–electron scattering and three-body recombination have been implemented in the system of rate equations. An algorithm for the numerical solution of the rate equations was simplified by incorporating analytical expressions for the cross sections of all the electron configurations in ions within the framework of the effective charge model. Using this approach, the time dependence of the inner shell populations during the time of XFEL pulse propagation through the crystal was evaluated for photon energies between 4 and 12 keV and a pulse width of 40 fs considering a flux of 1012 photons pulse−1 (focusing on a spot size of ∼1 µm. This flux corresponds to a fluence ranging between 0.8 and 2.4 mJ µm−2. The time evolution of the X-ray polarizability caused by the change of the atomic scattering factor during the pulse propagation is numerically analyzed for the case of a silicon crystal. The time-integrated polarizability drops dramatically if the fluence of the X-ray pulse exceeds 1.6 mJ µm−2.

Minocycline Does Not Decrease Intensity of Neuropathic Pain Intensity, But Does Improve Its Affective Dimension.

Science.gov (United States)

Sumitani, Masahiko; Ueda, Hiroshi; Hozumi, Jun; Inoue, Reo; Kogure, Takamichi; Yamada, Yoshitsugu; Kogure, Takamichi

2016-01-01

Recent understanding of the neuron-glia communication shed light on an important role of microglia to develop neuropathic pain The analgesic effect of minocycline on neuropathic pain is promising but it remains unclear in clinical settings. This study included 20 patients with neuropathic pain of varied etiologies. We administered 100 mg/day of minocycline for 1 week and then 200 mg/day for 3 weeks, as an open-label adjunct to conventional analgesics. An 11-point numerical rating scale. (NRS) and the short-form McGill Pain Questionnaire (SF-MPQ) were used to evaluate pain severity. The data were collected at baseline and after 4 weeks of therapy and analyzed using the Wilcoxon signed-rank test. All except two of the patients tolerated the full dose of minocycline. There was no significant improvement in the scoring of NRS (5.6 ± 1.2 at baseline vs. 5.3 ± 1.9 at 4 weeks; P =.60). The total score of the SF-MPQ decreased significantly (17.2 ± 7.4 vs. 13.9 ± 9.6; P =.02), particularly in the affective subscale (4.4 ± 2.7 vs. 3.3 ± 3.6; P =.007) but not so in the sensory subscale (12.8 ± 5.2 vs. 10.6 ± 6.2; P =.06). We conclude that minocycline failed to decrease pain intensity but succeeded in reducing the affective dimension associated with neuropathic pain.

Neonatal doses from X ray examinations by birth weight in a neonatal intensive care unit

Energy Technology Data Exchange (ETDEWEB)

Ono, K.; Akahane, K.; Aota, T.; Hada, M.; Takano, Y.; Kai, M.; Kusama, T

2003-07-01

The aim of this study was to investigate the frequency and type of X ray examinations performed on neonates classified according to their birth weight in a neonatal intensive care unit (NICU). In this study, the radiology records of 2408 neonates who were admitted to the NICU of Oita Prefectural Hospital between January 1994 and September 1999 were investigated. This study revealed that the neonates with earlier gestational ages and lower birth weights required longer NICU stays and more frequent X ray examinations made using a mobile X ray unit. The average number of X ray examinations performed on neonates of less than 750 g birth weight was 26 films per neonate. In regard to computed tomography and fluoroscopy, no significant relationship was found between the birth weight and number of X rays. This study revealed that the entrance-surface dose per neonate was dependent upon the birth weight, while the maximum dose was not dependent upon the birth weight. The average neonatal dose in the NICU was predominantly from computed tomography and fluoroscopy. The individual dose varied widely among neonates. (author)

Neonatal doses from X ray examinations by birth weight in a neonatal intensive care unit

International Nuclear Information System (INIS)

Ono, K.; Akahane, K.; Aota, T.; Hada, M.; Takano, Y.; Kai, M.; Kusama, T.

2003-01-01

The aim of this study was to investigate the frequency and type of X ray examinations performed on neonates classified according to their birth weight in a neonatal intensive care unit (NICU). In this study, the radiology records of 2408 neonates who were admitted to the NICU of Oita Prefectural Hospital between January 1994 and September 1999 were investigated. This study revealed that the neonates with earlier gestational ages and lower birth weights required longer NICU stays and more frequent X ray examinations made using a mobile X ray unit. The average number of X ray examinations performed on neonates of less than 750 g birth weight was 26 films per neonate. In regard to computed tomography and fluoroscopy, no significant relationship was found between the birth weight and number of X rays. This study revealed that the entrance-surface dose per neonate was dependent upon the birth weight, while the maximum dose was not dependent upon the birth weight. The average neonatal dose in the NICU was predominantly from computed tomography and fluoroscopy. The individual dose varied widely among neonates. (author)

The potential of detecting intermediate-scale biomass and canopy interception in a coniferous forest using cosmic-ray neutron intensity measurements and neutron transport modeling

Science.gov (United States)

Andreasen, M.; Looms, M. C.; Bogena, H. R.; Desilets, D.; Zreda, M. G.; Sonnenborg, T. O.; Jensen, K. H.

2014-12-01

The water stored in the various compartments of the terrestrial ecosystem (in snow, canopy interception, soil and litter) controls the exchange of the water and energy between the land surface and the atmosphere. Therefore, measurements of the water stored within these pools are critical for the prediction of e.g. evapotranspiration and groundwater recharge. The detection of cosmic-ray neutron intensity is a novel non-invasive method for the quantification of continuous intermediate-scale soil moisture. The footprint of the cosmic-ray neutron probe is a hemisphere of a few hectometers and subsurface depths of 10-70 cm depending on wetness. The cosmic-ray neutron method offers measurements at a scale between the point-scale measurements and large-scale satellite retrievals. The cosmic-ray neutron intensity is inversely correlated to the hydrogen stored within the footprint. Overall soil moisture represents the largest pool of hydrogen and changes in the soil moisture clearly affect the cosmic-ray neutron signal. However, the neutron intensity is also sensitive to variations of hydrogen in snow, canopy interception and biomass offering the potential to determine water content in such pools from the signal. In this study we tested the potential of determining canopy interception and biomass using cosmic-ray neutron intensity measurements within the framework of the Danish Hydrologic Observatory (HOBE) and the Terrestrial Environmental Observatories (TERENO). Continuous measurements at the ground and the canopy level, along with profile measurements were conducted at towers at forest field sites. Field experiments, including shielding the cosmic-ray neutron probes with cadmium foil (to remove lower-energy neutrons) and measuring reference intensity rates at complete water saturated conditions (on the sea close to the HOBE site), were further conducted to obtain an increased understanding of the physics controlling the cosmic-ray neutron transport and the equipment used

High-intensity laser physics

International Nuclear Information System (INIS)

Mohideen, U.

1993-01-01

This thesis is a study of the effect of high intensity lasers on atoms, free electrons and the generation of X-rays from solid density plasmas. The laser produced 50 milli Joule 180 femto sec pulses at 5 Hz. This translates to a maximum intensity of 5 x 10 18 W/cm 2 . At such high fields the AC stark shifts of atoms placed at the focus is much greater than the ionization energy. The characteristics of multiphoton ionization of atoms in intense laser fields was studied by angle resolved photoelectron spectroscopy. Free electrons placed in high intensity laser fields lead to harmonic generation. This phenomenon of Nonlinear Compton Scattering was theoretically investigated. Also, when these high intensity pulses are focused on solids a hot plasma is created. This plasma is a bright source of a short X-ray pulse. The pulse-width of X-rays from these solid density plasmas was measured by time-resolved X-ray spectroscopy

Scintillation properties and X-ray irradiation hardness of Ce3+-doped Gd2O3-based scintillation glass

International Nuclear Information System (INIS)

Liu, Liwan; Shao, Chongyun; Zhang, Yu; Liao, Xili; Yang, Qiuhong; Hu, Lili; Chen, Danping

2016-01-01

Ce 3+ -doped Gd 2 O 3 -based scintillation glasses are prepared within an air or CO atmosphere. The effects of fluorine, lutetium, barium, and the melting atmosphere on the optical properties, scintillation properties and irradiation hardness are studied. Absorption spectra, luminescence spectra under UV and X-ray excitation, and the X-ray radiation-induced spectra are presented. The results show that the density can be increased by doping with fluorine, lutetium and barium. The luminescence intensity decreases after X-ray irradiation. Because of charge transfer quenching, fluorine and lutetium enhance the UV-excited and X-ray excited luminescence intensity, but barium decreases. Moreover, fluorine and lutetium are advantageous to irradiation hardness while barium is not. In addition, a non-reducing atmosphere provides a higher irradiation hardness than a reducing atmosphere. Fluorine-doped glass is promising to enhance luminescence intensity, promote irradiation hardness, and increase the density.

Ultrashort x-ray pulse generation by nonlinear Thomson scattering of a relativistic electron with an intense circularly polarized laser pulse

Directory of Open Access Journals (Sweden)

F. Liu

2012-07-01

Full Text Available The nonlinear Thomson scattering of a relativistic electron with an intense laser pulse is calculated numerically. The results show that an ultrashort x-ray pulse can be generated by an electron with an initial energy of 5 MeV propagating across a circularly polarized laser pulse with a duration of 8 femtosecond and an intensity of about 1.1×10^{21}  W/cm^{2}, when the detection direction is perpendicular to the propagation directions of both the electron and the laser beam. The optimal values of the carrier-envelop phase and the intensity of the laser pulse for the generation of a single ultrashort x-ray pulse are obtained and verified by our calculations of the radiation characteristics.

The use of a CCD imaging system for X-ray film intensity measurement

International Nuclear Information System (INIS)

Grigg, M.W.; Barnea, Z.

1994-01-01

The use of a simple CCD-based imaging system for digitizing and x-ray film image is demonstrated. A method of extending the region of linear response of the film based upon an analytic representation of the observed response to a series of increasing exposures is described. The validity of the procedure is illustrated through an example of the absolute intensity measurement of a reflection of cadmium sulphide. 3 refs., 7 figs

Cueing properties of the decrease of white noise intensity for avoidance conditioning in cats.

Science.gov (United States)

Zieliński, K

1979-01-01

In the main experiment two groups of 6 cats each were trained in active bar-pressing avoidance to a CS consisting of either a 10 dB or 20 dB decrease of the background white noise of 70 dB intensity. The two groups did not differ in rapidity of learning, however cats trained to the greater change .in background noise performed avoidance responses with shorter latencies than did cats trained to smaller change. Within-groups comparisons of cumulative distributions of response latencies for consecutive Vincentized fifths of avoidance acquisition showed the greatest changes in the region of latencies longer than the median latency of instrumental responses. On the other hand, the effects of CS intensity found in between-groups comparisons were located in the region of latencies shorter than the median latency of either group. Comparisons with data obtained in a complementary experiment employing additional 17 cats showed that subjects trained to stimuli less intense than the background noise level were marked by an exceptionally low level of avoidance responding with latencies shorter than 1.1 s, which was lower than expected from the probability of intertrial responses for this period of time. Due to this property of stimuli less intense than the background, the distributions of response latencies were moved to the right, in effect, prefrontal lesions influenced a greater part of latency distributions than in cats trained to stimuli more intense than the background.

Kβ/ Kα intensity ratios for X-ray production in 3d metals by gamma-rays and protons

Science.gov (United States)

Bhuinya, C. R.; Padhi, H. C.

1994-04-01

Systematic measurements of Kβ/ Kα intensity ratios for X-ray production in 3d metals have been carried out using γ-ray and fast proton ionization methods. The measured ratios from proton ionization experiments indicate production of multivacancies in the L shell giving rise to higher Kβ/ Kα ratios compared to the present γRF results and 2 MeV proton ionization results of Perujo et al. [Perujo A., Maxwell J. A., Teesdale W. J. and Cambell J. L. (1987) J. Phys. B: Atom. Molec. Phys.20, 4973]. This is consistent with the SCA model calculation which gives increased simultaneous K- and L-shell ionization at 4 MeV. The present results from γRF experiments are in close agreement with the 2 MeV proton ionization results of Perujo et al. (1987) and also with the theoretical calculation of jankowski and Polasik [Jankowski K. and Polasik M. (1989) J. Phys. B: Atom. Molec. Optic. Phys. 22, 2369] but the theoretical results of Scofield [Scofield J. H. (1974a) Atom. Data Nucl. Data Tables14, 12] are somewhat higher.

GALACTIC COSMIC-RAY INTENSITY MODULATION BY COROTATING INTERACTION REGION STREAM INTERFACES AT 1 au

Energy Technology Data Exchange (ETDEWEB)

Guo, X. [State Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing, 100190 (China); Florinski, V. [Center for Space Plasma and Aeronomic Research, University of Alabama, Huntsville, AL 35899 (United States)

2016-07-20

We present a new model that couples galactic cosmic-ray (GCR) propagation with magnetic turbulence transport and the MHD background evolution in the heliosphere. The model is applied to the problem of the formation of corotating interaction regions (CIRs) during the last solar minimum from the period between 2007 and 2009. The numerical model simultaneously calculates the large-scale supersonic solar wind properties and its small-scale turbulent content from 0.3 au to the termination shock. Cosmic rays are then transported through the background, and thus computed, with diffusion coefficients derived from the solar wind turbulent properties, using a stochastic Parker approach. Our results demonstrate that GCR variations depend on the ratio of diffusion coefficients in the fast and slow solar winds. Stream interfaces inside the CIRs always lead to depressions of the GCR intensity. On the other hand, heliospheric current sheet (HCS) crossings do not appreciably affect GCR intensities in the model, which is consistent with the two observations under quiet solar wind conditions. Therefore, variations in diffusion coefficients associated with CIR stream interfaces are more important for GCR propagation than the drift effects of the HCS during a negative solar minimum.

GALACTIC COSMIC-RAY INTENSITY MODULATION BY COROTATING INTERACTION REGION STREAM INTERFACES AT 1 au

International Nuclear Information System (INIS)

Guo, X.; Florinski, V.

2016-01-01

We present a new model that couples galactic cosmic-ray (GCR) propagation with magnetic turbulence transport and the MHD background evolution in the heliosphere. The model is applied to the problem of the formation of corotating interaction regions (CIRs) during the last solar minimum from the period between 2007 and 2009. The numerical model simultaneously calculates the large-scale supersonic solar wind properties and its small-scale turbulent content from 0.3 au to the termination shock. Cosmic rays are then transported through the background, and thus computed, with diffusion coefficients derived from the solar wind turbulent properties, using a stochastic Parker approach. Our results demonstrate that GCR variations depend on the ratio of diffusion coefficients in the fast and slow solar winds. Stream interfaces inside the CIRs always lead to depressions of the GCR intensity. On the other hand, heliospheric current sheet (HCS) crossings do not appreciably affect GCR intensities in the model, which is consistent with the two observations under quiet solar wind conditions. Therefore, variations in diffusion coefficients associated with CIR stream interfaces are more important for GCR propagation than the drift effects of the HCS during a negative solar minimum.

Comparison between the measurements of Radon Gas Concentrations and γ-ray intensities in Exploring the Black Sands at El-Burullus Beach

International Nuclear Information System (INIS)

Abdel-Razek, Y.A; Bakhit, A.F

2009-01-01

Ten well-located monitoring stations along El-Burullus beach were chosen to measure radon gas concentrations in the beach sands below surface, and γ-ray intensities at 10 cm above the surface. These stations were chosen to represent apparent concentrations of the black sands. Sand samples were collected from the different stations and analyzed to study the relation between the concentrations of the heavy minerals and the measured radon concentrations or the measured γ-ray intensities at these stations. It was found that radon gas concentrations measured at 6:00 Pm were about 2.82 times those measured at 1 :00 Pm due to diurnal variation of temperature. Measurements of radon gas concentrations inside the beach sands are found to be more reliable in qualitative exploration of black sands than the measurements of γ-ray intensities above the shore sands due to the random arrangement of the layers of these sands below surface

Time Integrated Soft X-ray Imaging in High Intensity Laser Experiments (thesis)

Energy Technology Data Exchange (ETDEWEB)

Stafford, David [Univ. of California, Davis, CA (United States)

2009-01-01

2009 marks a significant achievement and the dawn of a new era in high intensity laser research with the final commissioning of all 192 beams at the National Ignition Facility (NIF). NIF is a department of energy (DOE) funded project more than 10 years in the making located at the Lawrence Livermore National Laboratory (LLNL). The following research was done as one of many preliminary experiments done to prepare for these historic events. The primary focus of the experimental campaign this paper addresses is to test and develop a thermal x-radiation source using a short pulse laser. This data is hoped to provide information about the thermal transport mechanisms important in the development of prediction models in High Energy Density (HED) science. One of several diagnostics fielded was a soft x-ray imager (SXRI) which is detailed in this paper. The SXRI will be used to measure the relative size of the heated region and also the relative level of specific x-ray emissions among several shot and target configurations. The laser system used was the Titan laser located in the Jupiter Laser Facility (JLF) at Lawrence Livermore National Laboratory (LLNL). Titan uses the JLF Janus Nd:glass laser west frontend system with a Optical Parametric Chirped Pulse Amplification (OPCPA) in place of the nanosecond oscillator. The system is capable of producing laser intensities of over a petawatt with several tens of joules delivered in the beam.

The effect of laser and X-rays on the invasive capability of the larvae of Fasciola hepatica L

International Nuclear Information System (INIS)

Bielecki, A.

1986-01-01

The material comprised eggs and larvae of F. hepatica and its hosts: intermediate - Galba truncatula (L.) and final (Mus. sp.). The eggs and larvae of F. hepatica were exposed to X-rays hard, 240 KV 20 R/s intensity and L-rays of a laser HE-Ne of low power 0.82 mW, light wave length 632.8 mm. The eggs were exposed at the first day of culture while the miracidia at the first hour of their life, using the doses of 1, 100, 200, 400, 600, 800, 1200 R in the case of X-rays and 5, 10, 15 and 30 min in the case of L-rays. In order to express the effect of irradiation on the invasive capability of the miracidia developing inside egg capsules those hatching of the eggs and of the adolescariae, the invasion index was calculated. In the case of miracidia all the doses of X-rays used in the experiment limit the number of adolescariae and adult flukes. The X-rays used at low doses in the case of adolescariae (1 R) increase the intensity of mouse infection with adult flukes, while higher doses (e.g. 1200 R) decrease the infection. The L-rays applied to miracidia cause an inrease in the number of cercariae developing per snail and the intensity of mouse infection also grows. In the case of adolescariae they decrease the intensity of mouse infection. In the flukes developing from larvae (miracidia, adolescariae) exposed to X- and L-rays the lack of eggs in the uterus was observed as well as the decrease of size. 43 refs., 5 figs., 6 tabs. (author)

Disk Disruptions and X-ray Intensity Excursions in Cyg X-2, LMC X-3 and Cyg X-3

Science.gov (United States)

Boyd, P. T.; Smale, A. P.

2001-05-01

The RXTE All Sky Monitor soft X-ray light curves of many X-ray binaries show long-term intensity variations (a.k.a "superorbital periodicities") that have been ascribed to precession of a warped, tilted accretion disk around the X-ray source. We have found that the excursion times between X-ray minima in Cyg X-2 can be characterized as a series of integer multiples of the 9.8 binary orbital period, (as opposed to the previously reported stable 77.7 day single periodicity, or a single modulation whose period changes slowly with time). While the data set is too short for a proper statistical analysis, it is clear that the length of any given intensity excursion cannot be used to predict the next (integer) excursion length in the series. In the black hole candidate system LMC X-3, the excursion times are shown to be related to each other by rational fractions. We find that the long term light curve of the unusual galactic X-ray jet source Cyg X-3 can also be described as a series of intensity excursions related to each other by integer multiples of a fundamental underlying clock. In the latter cases, the clock is apparently not related to the known binary periods. A unified physical model, involving both an inclined accretion disk and a fixed-probability disk disruption mechanism is presented, and compared with three-body scattering results. Each time the disk passes through the orbital plane it experiences a fixed probability P that it will disrupt. This model has testable predictions---the distribution of integers should resemble that of an atomic process with a characteristic half life. Further analysis can support or refute the model, and shed light on what system parameters effectively set the value of P.

Aerogel Cherenkov detector for characterizing the intense flash x-ray source, Cygnus, spectrum

Energy Technology Data Exchange (ETDEWEB)

Kim, Y., E-mail: yhkim@lanl.gov; Herrmann, H. W.; McEvoy, A. M.; Young, C. S.; Hamilton, C. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Schwellenbach, D. D.; Malone, R. M.; Kaufman, M. I.; Smith, A. S. [National Security Technologies, LLC, Los Alamos, New Mexico 87544 (United States)

2016-11-15

An aerogel Cherenkov detector is proposed to measure the X-ray energy spectrum from the Cygnus—intense flash X-ray source operated at the Nevada National Security Site. An array of aerogels set at a variety of thresholds between 1 and 3 MeV will be adequate to map out the bremsstrahlung X-ray production of the Cygnus, where the maximum energy of the spectrum is normally around 2.5 MeV. In addition to the Cherenkov radiation from aerogels, one possible competing light-production mechanism is optical transition radiation (OTR), which may be significant in aerogels due to the large number of transitions from SiO{sub 2} clusters to vacuum voids. To examine whether OTR is a problem, four aerogel samples were tested using a mono-energetic electron beam (varied in the range of 1–3 MeV) at NSTec Los Alamos Operations. It was demonstrated that aerogels can be used as a Cherenkov medium, where the rate of the light production is about two orders magnitude higher when the electron beam energy is above threshold.

Characterizing transverse coherence of an ultra-intense focused X-ray free-electron laser by an extended Young's experiment

Directory of Open Access Journals (Sweden)

Ichiro Inoue

2015-11-01

Full Text Available Characterization of transverse coherence is one of the most critical themes for advanced X-ray sources and their applications in many fields of science. However, for hard X-ray free-electron laser (XFEL sources there is very little knowledge available on their transverse coherence characteristics, despite their extreme importance. This is because the unique characteristics of the sources, such as the ultra-intense nature of XFEL radiation and the shot-by-shot fluctuations in the intensity distribution, make it difficult to apply conventional techniques. Here, an extended Young's interference experiment using a stream of bimodal gold particles is shown to achieve a direct measurement of the modulus of the complex degree of coherence of XFEL pulses. The use of interference patterns from two differently sized particles enables analysis of the transverse coherence on a single-shot basis without a priori knowledge of the instantaneous intensity ratio at the particles. For a focused X-ray spot as small as 1.8 µm (horizontal × 1.3 µm (vertical with an ultrahigh intensity that exceeds 1018 W cm−2 from the SPring-8 Ångstrom Compact free-electron LAser (SACLA, the coherence lengths were estimated to be 1.7 ± 0.2 µm (horizontal and 1.3 ± 0.1 µm (vertical. The ratios between the coherence lengths and the focused beam sizes are almost the same in the horizontal and vertical directions, indicating that the transverse coherence properties of unfocused XFEL pulses are isotropic. The experiment presented here enables measurements free from radiation damage and will be readily applicable to the analysis of the transverse coherence of ultra-intense nanometre-sized focused XFEL beams.

Impact of intense x-ray pulses on a NaI(Tl)-based gamma camera

Science.gov (United States)

Koppert, W. J. C.; van der Velden, S.; Steenbergen, J. H. L.; de Jong, H. W. A. M.

2018-03-01

In SPECT/CT systems x-ray and γ-ray imaging is performed sequentially. Simultaneous acquisition may have advantages, for instance in interventional settings. However, this may expose a gamma camera to relatively high x-ray doses and deteriorate its functioning. We studied the NaI(Tl) response to x-ray pulses with a photodiode, PMT and gamma camera, respectively. First, we exposed a NaI(Tl)-photodiode assembly to x-ray pulses to investigate potential crystal afterglow. Next, we exposed a NaI(Tl)-PMT assembly to 10 ms LED pulses (mimicking x-ray pulses) and measured the response to flashing LED probe-pulses (mimicking γ-pulses). We then exposed the assembly to x-ray pulses, with detector entrance doses of up to 9 nGy/pulse, and analysed the response for γ-pulse variations. Finally, we studied the response of a Siemens Diacam gamma camera to γ-rays while exposed to x-ray pulses. X-ray exposure of the crystal, read out with a photodiode, revealed 15% afterglow fraction after 3 ms. The NaI(Tl)-PMT assembly showed disturbances up to 10 ms after 10 ms LED exposure. After x-ray exposure however, responses showed elevated baselines, with 60 ms decay-time. Both for x-ray and LED exposure and after baseline subtraction, probe-pulse analysis revealed disturbed pulse height measurements shortly after exposure. X-ray exposure of the Diacam corroborated the elementary experiments. Up to 50 ms after an x-ray pulse, no events are registered, followed by apparent energy elevations up to 100 ms after exposure. Limiting the dose to 0.02 nGy/pulse prevents detrimental effects. Conventional gamma cameras exhibit substantial dead-time and mis-registration of photon energies up to 100 ms after intense x-ray pulses. This is due PMT limitations and due to afterglow in the crystal. Using PMTs with modified circuitry, we show that deteriorative afterglow effects can be reduced without noticeable effects on the PMT performance, up to x-ray pulse doses of 1 nGy.

Early Exercise in the Burn Intensive Care Unit Decreases Hospital Stay, Improves Mental Health, and Physical Performance

Science.gov (United States)

2017-10-01

Decreases Hospital Stay, Improves Mental Health , and Physical Performance 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Oscar E. Suman, PhD...Multicenter Study of the Effect of In-Patient Exercise Training on Length of Hospitalization, Mental Health , and Physical Performance in Burned...Intensive Care Unit Decreases Hospital Stay, Improves Mental Health , and Physical Performance,” Proposal Log Number 13214039, Award Number W81XWH-14

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

Energy Technology Data Exchange (ETDEWEB)

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

2014-09-15

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

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

International Nuclear Information System (INIS)

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

2014-01-01

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

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

Science.gov (United States)

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

2014-09-01

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

Measurement of relative intensities of L-shell X-rays of some heavy elements using Cd-109 radioisotope source

International Nuclear Information System (INIS)

Darko, J.B.; Tetteh, G.K.

1992-01-01

The relative L-shell x-ray intensities of Sm, W, Ir, Au, Hg, Pb and U were measured using a Cd-109 radioisotope source and a Si(Li) detector. The measured relative intensities were compared with the theoretically calculated values due to Scofield, computed for the present excitation energy of 22.6 keV. The experimental results were found to agree with theory in most cases. (author)

Measurement of relative intensities of L-shell X-rays of some heavy elements using Cd-109 radioisotope source

Energy Technology Data Exchange (ETDEWEB)

Darko, J.B.; Tetteh, G.K. (Ghana Univ., Legon (Ghana). Dept. of Physics)

The relative L-shell x-ray intensities of Sm, W, Ir, Au, Hg, Pb and U were measured using a Cd-109 radioisotope source and a Si(Li) detector. The measured relative intensities were compared with the theoretically calculated values due to Scofield, computed for the present excitation energy of 22.6 keV. The experimental results were found to agree with theory in most cases. (author).

Effect of external magnetic field on the Kβ/Kα X-ray intensity ratios of TixNi1-x alloys excited by 59.54 and 22.69keV photons.

Science.gov (United States)

Perişanoğlu, Ufuk; Alım, Bünyamin; Uğurlu, Mine; Demir, Lütfü

2016-09-01

The effects of external magnetic field and exciting photon energies on the Kβ/Kα X-ray intensity ratios of various alloy compositions of Ti-Ni transition metal alloys have been investigated in this work using X-ray fluorescence spectroscopy. The spectrum of characteristic K-X-ray photons from pure Ti, pure Ni and TixNi1-x (x=0.30; 0.40; 0.50; 0.60; 0.70) alloys were detected with a high resolution Si (Li) solid-state detector. Firstly, Kβ/Kα X-ray intensity ratios of pure Ti, pure Ni and TixNi1-x alloys were measured following excitation by 59.54keV γ-rays from a 200mCi (241)Am radioactive point source without any magnetic field and under 0.5 and 1T external magnetic fields, separately. Later, the same measurements were repeated under the same experimental conditions for 22.69keV X-rays from a 370 MBq(1)(0)(9)Cd radioactive point source. The results obtained for Kβ/Kα X-ray intensity ratios of pure Ti, pure Ni, Ti and Ni in various Ti-Ni alloys were evaluated in terms of both external magnetic field effect and exciting photon energy effect. When the results obtained for both exciting photon energies are evaluated in terms of changing of Kβ/Kα X-ray intensity ratios depending on the alloy composition, the tendency of these changes are observed to be similar. Also, Kβ/Kα X-ray intensity ratios for all samples examined have changed with increasing external magnetic field. Therefore, the results obtained have shown that Kβ/Kα X-ray intensity ratios of Ti and Ni in TixNi1-x alloys are connected with the external magnetic field. The present study makes it possible to perform reliable interpretation of experimental Kβ/Kα X-ray intensity ratios for Ti, Ni and TixNi1-x alloys and can also provide quantitative information about the changes of the Kβ/Kα X-ray intensity ratios of these metals with alloy composition. Copyright © 2016 Elsevier Ltd. All rights reserved.

Intensity variation of cosmic rays near the heliospheric current sheet

International Nuclear Information System (INIS)

Badruddin, K.S.; Yadav, R.S.; Yadav, N.R.

1985-01-01

Cosmic ray intensity variations near the heliospheric current sheet-both above and below it-have been studied during 1964-76. Superposed epoch analysis of the cosmic ray neutron monitor data with respect to sector boundaries (i.e., heliospheric current sheet crossings) has been performed. In this analysis data from neutron monitors well distributed in latitude over the Earth's surface is used. First, this study has been made during the two solar activity minimum periods 1964-65 and 1975-76, using the data from Thule (cut-off rigidity O GV), Deep River (cut-off rigidity 1.02 GV), Rome (cut-off rigidity 6.32 GV) and Huancayo (cut-off rigidity 13.45 GV) neutron monitors. The data is analyzed from Deep River, Rome and Huancayo neutron monitors, for which data is available for the full period (1964-76), by dividing the periods according to the changes in solar activity, interplanetary magnetic field polarity and coronal holes. All these studies have shown a negative gradient with respect to heliomagnetic latitude (current sheet). These results have been discussed in the light of theoretical and observational evidences. Suggestions have been given to overcome the discrepancy between the observational and theoretical results. Further, possible explanations for these observational results have been suggested. (author)

Study of characteristics of Forbush decreases detected in 2006 – 2011 by means of muon hodoscope URAGAN

International Nuclear Information System (INIS)

Barbashina, N S; Astapov, I I; Borog, V V; Dmitrieva, A N; Kokoulin, R P; Kompaniets, K G; Mishutina, Yu N; Petrukhin, A A; Shutenko, V V; Sit'ko, O A; Yakovleva, E I; Yashin, I I

2013-01-01

Results of the study of variations of cosmic ray muon flux at the Earth surface during Forbush decreases (FD) registered in 2006 – 2011 by means of muon hodoscope URAGAN both for the integral counting rate and for different angular intervals are presented. Dependences of the amplitude of the decrease of cosmic ray muon intensity on the energy of primary particles in the energy region above 10 GeV during different phases of the FD were obtained. On the basis of the analysis of spatial-angular distribution of muon flux, values of the horizontal projections of the local anisotropy vector were calculated and their dynamics was studied. Energy, angular and temporal characteristics of Forbush decreases determined from cosmic ray muon data are compared with basic parameters characterizing conditions of near-Earth space before and during FD.

Results of a search for paraphotons with intense X-ray beams at SPring-8

International Nuclear Information System (INIS)

Inada, T.; Namba, T.; Asai, S.; Kobayashi, T.; Tanaka, Y.; Tamasaku, K.; Sawada, K.; Ishikawa, T.

2013-01-01

A search for paraphotons, or hidden U(1) gauge bosons, is performed using an intense X-ray beamline at SPring-8. “Light Shining through a Wall” technique is used in this search. No excess of events above background is observed. A stringent constraint is obtained on the photon–paraphoton mixing angle, χ −5 (95% C.L.) for 0.04 eV γ ′ <26 keV

Sources of linear polarized x-rays

International Nuclear Information System (INIS)

Aiginger, H.; Wobrauschek, P.

1989-01-01

Linear polarized X-rays are used in X-ray fluorescence analysis to decrease the background caused by scattered photons. Various experiments, calculations and constructions have demonstrated the possibility to produce polarized radiation in an analytical laboratory with an X-ray tube and polarizer-analyzer facilities as auxiliary equipment. The results obtained with Bragg-polarizers of flat and curved focussing geometry and of Barkla-polarizers are presented. The advantages and disadvantages of the method are discussed and compared with the respective quality of synchrotron radiation. Polarization by scattering reduces the intensity of the primary radiation. Recently much effort is devoted to the construction of integrated high power X-ray tube polarizer-analyzer arrangements. The detailed design, geometry and performance of such a facility is described. (author)

A high intensity beam line of γ-rays up to 22MeV energy based on Compton backscattering

International Nuclear Information System (INIS)

Guo, W.; Xu, W.; Chen, J.G.; Ma, Y.G.; Cai, X.Z.; Wang, H.W.; Xu, Y.; Wang, C.B.; Lu, G.C.; Tian, W.D.; Yuan, R.Y.; Xu, J.Q.; Wei, Z.Y.; Yan, Z.; Shen, W.Q.

2007-01-01

Shanghai Laser Electron Gamma Source, a high intensity beam line of γ-ray, has been proposed recently. The beam line is expected to generate γ-rays up to the maximum energy of 22MeV by Compton backscattering between a CO 2 laser and electrons in the 3.5 GeV storage ring of the Shanghai Synchrotron Radiation Facility. The flux of non-collimated γ-rays is estimated to be 10 9 -10 10 s -1 when a CO 2 laser of several hundred Watt power is employed. We will discuss physics issues in the design and optimization of the beam line

A theoretical model predicting the intensity of emitted light per unit of x-ray exposure in radiographic screens

Energy Technology Data Exchange (ETDEWEB)

Tsoukos, S; Kateris, A; Kalivas, N; Spyrou, G; Panayiotakis, G [Department of Medical Physics, School of Medicine, University of Patras, 265 00 pAtras (Greece); Kandarakis, I; Gavouras, D [Department of Medical Instrumentation Technology, Technological Educational Institution of Athens (Greece)

1999-12-31

A theoretical model predicting the intensity of light emitted by x-ray imaging phosphor screens per unit of area and time over incident x-ray flux (absolute efficiency) was developed. The model takes into account : A) the structure of the screens which consists of luminescent grains embedded in a binding matrix. B) the direct deposition of energy by x-ray absorption effects.. C) the re-absorption of K fluorescence characteristic x-rays produced when the x-ray energy exceeds the energy of the K absorption edge of the phosphor material. To test the model a set of (Gd,La)2O2S:Tb phosphor screens was prepared by sedimentation in the laboratory. Experimental absolute efficiency data were obtained at x-ray tube voltage range from 40 to 160 kVp. The coincidence between experimental and theoretical results were satisfactory. (authors) 7 refs., 4 figs.

On the multiphoton emission during U.V. and X-ray absorption by atoms in intense laser fields

International Nuclear Information System (INIS)

Miranda, L.C.M.

1981-09-01

A discussion of the u.v. and x-ray absorption cross section by a hydrogen atom in the presence of an intense i.r. laser field is presented, taking into account the influence of laser field on the electronic states. (Author) [pt

Measurements of decay heat and gamma-ray intensity of spent LWR fuel assemblies

International Nuclear Information System (INIS)

Vogt, J.; Agrenius, L.; Jansson, P.; Baecklin, A.; Haakansson, A.; Jacobsson, S.

1999-01-01

Calorimetric measurements of the decay heat of a number of BWR and PWR fuel assemblies have been performed in the pools at the Swedish Central Interim Storage Facility for Spent Nuclear Fuel, CLAB. Gamma-ray measurements, using high-resolution gamma-ray spectroscopy (HRGS), have been carried out on the same fuel assemblies in order to test if it is possible to find a simple and accurate correlation between the 137 CS -intensity and the decay heat for fuel with a cooling time longer than 10-12 years. The results up to now are very promising and may ultimately lead to a qualified method for quick and accurate determination of the decay heat of old fuel by gamma-ray measurements. By means of the gamma spectrum the operator declared data on burnup, cooling time and initial enrichment can be verified as well. CLAB provides a unique opportunity in the world to follow up the decay heat of individual fuel assemblies during several decades to come. The results will be applicable for design and operation of facilities for wet and dry interim storage and subsequent encapsulation for final disposal of the fuel. (author)

Fast voxel and polygon ray-tracing algorithms in intensity modulated radiation therapy treatment planning

International Nuclear Information System (INIS)

Fox, Christopher; Romeijn, H. Edwin; Dempsey, James F.

2006-01-01

We present work on combining three algorithms to improve ray-tracing efficiency in radiation therapy dose computation. The three algorithms include: An improved point-in-polygon algorithm, incremental voxel ray tracing algorithm, and stereographic projection of beamlets for voxel truncation. The point-in-polygon and incremental voxel ray-tracing algorithms have been used in computer graphics and nuclear medicine applications while the stereographic projection algorithm was developed by our group. These algorithms demonstrate significant improvements over the current standard algorithms in peer reviewed literature, i.e., the polygon and voxel ray-tracing algorithms of Siddon for voxel classification (point-in-polygon testing) and dose computation, respectively, and radius testing for voxel truncation. The presented polygon ray-tracing technique was tested on 10 intensity modulated radiation therapy (IMRT) treatment planning cases that required the classification of between 0.58 and 2.0 million voxels on a 2.5 mm isotropic dose grid into 1-4 targets and 5-14 structures represented as extruded polygons (a.k.a. Siddon prisms). Incremental voxel ray tracing and voxel truncation employing virtual stereographic projection was tested on the same IMRT treatment planning cases where voxel dose was required for 230-2400 beamlets using a finite-size pencil-beam algorithm. Between a 100 and 360 fold cpu time improvement over Siddon's method was observed for the polygon ray-tracing algorithm to perform classification of voxels for target and structure membership. Between a 2.6 and 3.1 fold reduction in cpu time over current algorithms was found for the implementation of incremental ray tracing. Additionally, voxel truncation via stereographic projection was observed to be 11-25 times faster than the radial-testing beamlet extent approach and was further improved 1.7-2.0 fold through point-classification using the method of translation over the cross product technique

Theoretical calculations of L alpha one x-ray emission intensity ratios for uranium in various matrices: a comparison with experimental values

International Nuclear Information System (INIS)

Anderson, L.D.

1976-01-01

The U L/sub α1/ x-ray emission intensity ratios (I/sub lambda/sub L//I sub lambda/sub L/, sub 100 percent/sub UO 2 /) in various matrices were calculated using the fundamental parameters formula of Criss and Birks and mass absorption coefficients calculated from a formula developed by Dewey. The use of the intensity ratio made it unnecessary to know the fluorescence yield for the U L/sub III/ level, the probability of emission of the U L/sub α1/ line, and the jump ratios for the three absorption edges of uranium. Also, since an intensity ratio was used, the results are independent of the x-ray tube current and the spectral distribution of the x-ray tube. A method is presented to calculate the intensity ratios for x-ray tube voltages other than the value (45 kV) used in the calculations. The theoretical results are calculated and compared with the experimental results obtained for 141 matrices. Difficulties due to oxidation of some of the metal powders used in the sample preparation, to small concentrations of uranium, and to an excessively large number of elements present in some of the samples resulted in the invalidation of the experimental results for 91 of the matrices. For the remaining 50 matrices, the theoretical and experimental values agreed to within +-5 percent relative error for 36 matrices; to within +-5 percent to +- 10 percent for 7 matrices; to within +-10 percent to +-20 percent for 6 matrices; and was greater than +-20 percent for 1 matrix

High-intensity laser synchrotron x-ray source

International Nuclear Information System (INIS)

Pogorelsky, I.V.

1995-10-01

A laser interacting with a relativistic electron beam behaves like a virtual wiggler of an extremely short period equal to half of the laser wavelength. This approach opens a route to relatively compact, high-brightness x-ray sources alternative or complementary to conventional synchrotron light sources. Although not new, the Laser Synchrotron Light Source (LSLS) concept is still waiting for a convincing demonstration. Available at the BNL's Accelerator Test Facility (ATF), a high-brightness electron beam and the high-power C0 2 laser may be used as prototype LSLS brick stones. In a feasible demonstration experiment, 10-GW, 100-ps C0 2 laser beam will be brought to a head-on collision with a 10-ps, 0.5-nC, 70 MeV electron bunch. Flashes of well-collimated, up to 9.36-keV (∼ Angstrom) x-rays of 10-ps pulse duration, with a flux of ∼10 19 photons/sec will be produced via linear Compton backscattering. The x-ray spectrum is tunable proportionally to a variable e-beam energy. A natural short-term extension of the proposed experiment would be further enhancement of the x-ray flux to a 10 21 -10 22 photons/sec level, after the ongoing ATF CO 2 laser upgrade to 1 TW peak power and electron bunch shortening to 3 ps. The ATF LSLS x-ray beamline, exceeding by orders of magnitude the peak fluxes attained at the National Synchrotron Light Source (NSLS) x-ray storage ring, may become attractive for certain users, e.g., for biological x-ray microscopy. In addition, a terawatt CO 2 laser will enable harmonic multiplication of the x-ray spectrum via nonlinear Compton scattering

Beta decay of the fission product 125Sb and a new complete evaluation of absolute gamma ray transition intensities

Science.gov (United States)

Rajput, M. U.; Ali, N.; Hussain, S.; Mujahid, S. A.; MacMahon, D.

2012-04-01

The radionuclide 125Sb is a long-lived fission product, which decays to 125Te by negative beta emission with a half-life of 1008 day. The beta decay is followed by the emission of several gamma radiations, ranging from low to medium energy, that can suitably be used for high-resolution detector calibrations, decay heat calculations and in many other applications. In this work, the beta decay of 125Sb has been studied in detail. The complete published experimental data of relative gamma ray intensities in the beta decay of the radionuclide 125Sb has been compiled. The consistency analysis was performed and discrepancies found at several gamma ray energies. Evaluation of the discrepant data was carried out using Normalized Residual and RAJEVAL methods. The decay scheme balance was carried out using beta branching ratios, internal conversion coefficients, populating and depopulating gamma transitions to 125Te levels. The work has resulted in the consistent conversion factor equal to 29.59(13) %, and determined a new evaluated set of the absolute gamma ray emission probabilities. The work has also shown 22.99% of the delayed intensity fraction as outgoing from the 58 d isomeric 144 keV energy level and 77.01% of the prompt intensity fraction reaching to the ground state from the other excited states. The results are discussed and compared with previous evaluations. The present work includes additional experimental data sets which were not included in the previous evaluations. A new set of recommended relative and absolute gamma ray emission probabilities is presented.

Beta decay of the fission product 125Sb and a new complete evaluation of absolute gamma ray transition intensities

International Nuclear Information System (INIS)

Rajput, M.U.; Ali, N.; Hussain, S.; Mujahid, S.A.; MacMahon, D.

2012-01-01

The radionuclide 125 Sb is a long-lived fission product, which decays to 125 Te by negative beta emission with a half-life of 1008 day. The beta decay is followed by the emission of several gamma radiations, ranging from low to medium energy, that can suitably be used for high-resolution detector calibrations, decay heat calculations and in many other applications. In this work, the beta decay of 125 Sb has been studied in detail. The complete published experimental data of relative gamma ray intensities in the beta decay of the radionuclide 125 Sb has been compiled. The consistency analysis was performed and discrepancies found at several gamma ray energies. Evaluation of the discrepant data was carried out using Normalized Residual and RAJEVAL methods. The decay scheme balance was carried out using beta branching ratios, internal conversion coefficients, populating and depopulating gamma transitions to 125 Te levels. The work has resulted in the consistent conversion factor equal to 29.59(13) %, and determined a new evaluated set of the absolute gamma ray emission probabilities. The work has also shown 22.99% of the delayed intensity fraction as outgoing from the 58 d isomeric 144 keV energy level and 77.01% of the prompt intensity fraction reaching to the ground state from the other excited states. The results are discussed and compared with previous evaluations. The present work includes additional experimental data sets which were not included in the previous evaluations. A new set of recommended relative and absolute gamma ray emission probabilities is presented.

Studies in cosmic rays

International Nuclear Information System (INIS)

Bemalkhedkar, M.M.

1974-03-01

The investigation of the diurnal variation in the cosmic ray intensity on individual days has revealed a new class of diurnal variation showing a maximum around 09 hour direction in the interplanetary space. It is shown to occur during the recovery phase of Forbush decreases as well as during quiet periods. The rigidity spectrum of the anomalous diurnal variation has an exponent around zero, the same as that for the average diurnal variation exhibiting maximum around 18 hours in the interplanetary space. It is shown that the Forbush decreases associated with the diurnal variation exhibiting morning maximum, are 27 day recurrent in nature and are preceded by east limb solar flares on most of the occasions. A qualitative model of the transient modulation by solar corotating corpuscular streams of enhanced solar wind velocity, emanating from the active regions on the solar disc, is proposed to explain the anomalous diurnal anisotropy in the recovery phase of 27 day recurrent Forbush decreases. From this model, the cosmic ray diffusion coefficients, parallel and perpendicular to the interplanetary magnetic field inside the corotating stream, are derived and compared with the average values. To investigate the possibility of determining the energy spectra of cosmic ray intensity variations from a single station, a continuous record of neutron multiplicity spectrum has been obtained for the period October, 1967 - October, 1971, using the Gulmarg neutron monitor. The average multiplicity spectrum in the Gulmarg neutron monitor shows a mean multiplicity approximately equal to 1.4 for 12 Boron-tri-fluoride counters and is an increasing function of the number of counters used. The mean multiplicity measured in various other neutron monitors, when normalized to the cutoff rigidity of Gulmurg (11.91 GV), shows a systematic increase with the altitude of the station. (author)

Monte Carlo simulation on hard X-ray dose produced in interaction between high intensity laser and solid target

International Nuclear Information System (INIS)

Yang Bo; Qiu Rui; Li Junli; Zhang Hui

2014-01-01

The X-ray dose produced in the interaction between high intensity laser and solid target was studied by simulation using Monte Carlo code. Compared with experimental results, the calculation model was verified. The calculation model was used to study the effect on X-ray dose with different electron temperatures, target materials (including Au, Cu and PE) and thicknesses. The results indicate that the X-ray dose is mainly determined by the electron temperature, and will be affected by the target parameters. X-ray dose of Au is about 1.2 times that of Cu, and is about 5 times that of PE (polyethylene). In addition, compared with other target thickness, when target thickness is the mean range of electron in the target, X-ray dose is relatively large. These results will provide references on evaluating the ionizing radiation dose for laser devices. (authors)

Deriving the solar activity cycle modulation on cosmic ray intensity observed by Nagoya muon detector from October 1970 until December 2012

Science.gov (United States)

de Mendonça, Rafael R. S.; Braga, Carlos. R.; Echer, Ezequiel; Dal Lago, Alisson; Rockenbach, Marlos; Schuch, Nelson J.; Munakata, Kazuoki

2017-10-01

It is well known that the cosmic ray intensity observed at the Earth's surface presents an 11 and 22-yr variations associated with the solar activity cycle. However, the observation and analysis of this modulation through ground muon detectors datahave been difficult due to the temperature effect. Furthermore, instrumental changes or temporary problems may difficult the analysis of these variations. In this work, we analyze the cosmic ray intensity observed since October 1970 until December 2012 by the Nagoya muon detector. We show the results obtained after analyzing all discontinuities and gaps present in this data and removing changes not related to natural phenomena. We also show the results found using the mass weighted method for eliminate the influence of atmospheric temperature changes on muon intensity observed at ground. As a preliminary result of our analyses, we show the solar cycle modulation in the muon intensity observed for more than 40 years.

High-Intensity Telemedicine Decreases Emergency Department Use by Senior Living Community Residents.

Science.gov (United States)

Shah, Manish N; Wasserman, Erin B; Wang, Hongyue; Gillespie, Suzanne M; Noyes, Katia; Wood, Nancy E; Nelson, Dallas; Dozier, Ann; McConnochie, Kenneth M

2016-03-01

The failure to provide timely acute illness care can lead to adverse consequences or emergency department (ED) use. We evaluated the effect on ED use of a high-intensity telemedicine program that provides acute illness care for senior living community (SLC) residents. We performed a prospective cohort study over 3.5 years. Six SLCs cared for by a primary care geriatrics practice were intervention facilities, with the remaining 16 being controls. Consenting patients at intervention facilities could access telemedicine for acute illness care. Patients were provided patient-to-provider, real-time, or store-and-forward high-intensity telemedicine (i.e., technician-assisted with resources beyond simple videoconferencing) to diagnose and treat acute illnesses. The primary outcome was the rate of ED use. We enrolled 494 of 705 (70.1%) subjects/proxies in the intervention group; 1,058 subjects served as controls. Control and intervention subjects visited the ED 2,238 and 725 times, respectively, with 47.3% of control and 43.4% of intervention group visits resulting in discharge home. Among intervention subjects, ED use decreased at an annualized rate of 18% (rate ratio [RR]=0.82; 95% confidence interval [CI], 0.70-0.95), whereas in the control group there was no statistically significant change in ED use (RR=1.01; 95% CI, 0.95-1.07; p=0.009 for group-by-time interaction). Primary care use and mortality were not significantly different. High-intensity telemedicine significantly reduced ED use among SLC residents without increasing other utilization or mortality. This alternative to traditional acute illness care can enhance access to acute illness care and should be integrated into population health programs.

Low- and high-frequency spectral behavior of cosmic-ray intensity for the period 1953–1996

Directory of Open Access Journals (Sweden)

H. Mavromichalaki

2003-08-01

Full Text Available A study of the cosmic-ray intensity power spectrum using the Climax Neutron Monitor data in the frequency range from 10-9 Hz to 10-7 Hz (which corresponds to periodicities from 11 years to a few months during the period 1953–1996, was carried out by means of the successive approximations method of analysis and was compared against the power spectrum and the maximum entropy methods. The contributions of the time evolution of several peaks to the global one were obtained. Except for the well-known 11-year and the 1-year variations, peaks at 7.7, 5.5, 2 and 1.7 years are found. Several peaks with periods less than 10 months have appeared in our analysis, while the occurrence of 5.1 months is obtained in all the examined solar cycles with a strong signature in cycle 21. Transitions of these quasi-periodicities are seen in power spectra plots. Some of them can be attributed to the modulation of the cosmic ray intensity by solar activity. Others are sporadic and have been previously attributed to the interplanetary magnetic field. The results obtained support once again the argument regarding the difference in the solar activity between odd and even solar cycles.Key words. Interplanetary physics (Cosmic rays, Interplanetary magnetic fields

Solar-flare-induced Forbush decreases - Dependence on shock wave geometry

Science.gov (United States)

Thomas, B. T.; Gall, R.

1984-01-01

It is argued that the principal mechanism for the association of Forbush decreases with the passage of a solar flare shock wave is prolonged containment of cosmic ray particles behind the flare compression region, which acts as a semipermeable obstacle to particle motion along the field lines, leading to additional adiabatic cooling of the particles. Liouville's theorem is used to calculate the instantaneous distribution function at 1 AU for each particle arriving at the earth. By averaging over a large number of individual estimates, a representative estimate of the omnidirectional phase space density and the corresponding particle intensity is obtained. The energy change of individual particles at the shocks is found to be small in comparison to the energy lost by adiabatic cooling of the cosmic rays between the shock wave and the sun. The effects of particle rigidity, diffusion coefficient, and flare longitude on the magnitude of the Forbush decrease are quantitatively investigated.

Observation of material, thickness, and bremsstrahlung x-ray intensity dependent effects in moderate and high Z targets in a gamma and x-ray LIDAR experiment

Energy Technology Data Exchange (ETDEWEB)

Zhang, Xiaodong, E-mail: xzhang39@utk.edu [Department of Nuclear Engineering, University of Tennessee, TN 37996 (United States); Ayaz-Maierhafer, Birsen; Laubach, Mitchell A. [Department of Nuclear Engineering, University of Tennessee, TN 37996 (United States); Hayward, Jason P. [Department of Nuclear Engineering, University of Tennessee, TN 37996 (United States); Oak Ridge National Lab, Oak Ridge, TN 37831 (United States)

2015-06-01

A high energy gamma and x-ray LIDAR system consisting of a fast pulse (~50 ps, FWHM) LINAC and a Cherenkov detection system was used to investigate response differences among materials, their thicknesses, and bremsstrahlung x-ray intensities. The energies and pulse width of electrons used to produce bremsstrahlung x-rays were set at 20 or 40 MeV and 50 ps FWHM duration, respectively. The Cherenkov detector was built with a fused silica glass optically coupled to a 51 mm fast timing photomultiplier tube, which has an intrinsic energy threshold of 340.7 keV for Compton backscattered gammas. Such a fast detection system yields a coincidence resolving time of 93 ps FWHM, which is equivalent to a depth resolving capability of about 3 cm FWHM. The thicknesses of iron and lead targets were varied from 1 in. to 7 in. with a step of 1 in., and the thicknesses of DU were varied from 1/3 in. to 1 in. with a step of 1/3 in. The experimental results show that iron targets tend to produce a factor of five less observed x-rays and gammas, with less energetic photoelectron frequency distributions, compared with DU and lead targets for the same beam intensity and target thicknesses. Additionally, the self-shielding effect causes the lead to yield more gammas than the DU considering the experimental observation point. For the setup used in this study, a charge per pulse in the range of 1–2.5 nC yields the best resolving capability between the DU and lead targets.

Measurement of L X-ray intensity ratios in tantalum by proton and Si-ion impact

International Nuclear Information System (INIS)

Braich, J.S.; Dhal, B.B.; Singh, B.P.; Padhi, H.C.; Khurana, C.S.; Verma, H.R.

1996-01-01

The Lι, Lβ 1,4,6 , Lβ 2,15,3 , Lγ 1 , Lγ 2,3,6 and Lγ 4,4' , X-ray intensities relative to the Lα, caused by the impact of protons of energy 1 to 4.6 MeV and Si-ions of 70 to 98 MeV on Ta targets, h ave been measured. The results show that the intensity ratios drop significantly for all transitions except Lγ 2,3,6 /Lα with Si-ions of the same energy/amu as compared to those of protons. The experimental results have been compared with those based on the ECPSSR theoretical values. From the energy shift and change in the intensity ratios of various transitions caused by Si-ion impact, the number of outer shell vacancies in the M, N and O-shells simultaneous to that of L-shell have been estimat ed. (orig.)

Evaluation of the productivity decrease risk due to a future increase in tropical cyclone intensity in Japan.

Science.gov (United States)

Esteban, Miguel; Longarte-Galnares, Gorka

2010-12-01

A number of scientists have recently conducted research that shows that tropical cyclone intensity is likely to increase in the future. This would result in an increase in the damage along with a decrease in economic productivity due to precautionary cessation of the economic activity of the affected areas during the passage of the cyclone. The economic effect of this stop in economic activity is a phenomenon that has not received much attention in the past, and the cumulative effect that it can have on the Japanese economy over the next 75 years has never been evaluated. The starting point for the evaluation of the economic risks is the change in the patterns of tropical cyclone intensity suggested by Knutson and Tuleya. The results obtained show how a significant decrease in the overall productivity of the country could be expected, which could lower GDP by between 6% and 13% by 2085. © 2010 Society for Risk Analysis.

Polarized X-ray excitation for scatter reduction in X-ray fluorescence computed tomography.

Science.gov (United States)

Vernekohl, Don; Tzoumas, Stratis; Zhao, Wei; Xing, Lei

2018-05-25

X-ray fluorescence computer tomography (XFCT) is a new molecular imaging modality which uses X-ray excitation to stimulate the emission of fluorescent photons in high atomic number contrast agents. Scatter contamination is one of the main challenges in XFCT imaging which limits the molecular sensitivity. When polarized X-rays are used, it is possible to reduce the scatter contamination significantly by placing detectors perpendicular to the polarization direction. This study quantifies scatter contamination for polarized and unpolarized X-ray excitation and determines the advantages of scatter reduction. The amount of scatter in preclinical XFCT is quantified in Monte Carlo simulations. The fluorescent X-rays are emitted isotropically, while scattered X-rays propagate in polarization direction. The magnitude of scatter contamination is studied in XFCT simulations of a mouse phantom. In this study, the contrast agent gold is examined as an example but a scatter reduction from polarized excitation is also expected for other elements. The scatter reduction capability is examined for different polarization intensities with a monoenergetic X-ray excitation energy of 82 keV. The study evaluates two different geometrical shapes of CZT detectors which are modeled with an energy resolution of 1 keV FWHM at an X-ray energy of 80 keV. Benefits of a detector placement perpendicular to the polarization direction are shown in iterative and analytic image reconstruction including scatter correction. The contrast to noise ratio (CNR) and the normalized mean square error (NMSE) are analyzed and compared for the reconstructed images. A substantial scatter reduction for common detector sizes was achieved for 100% and 80% linear polarization while lower polarization intensities provide a decreased scatter reduction. By placing the detector perpendicular to the polarization direction, a scatter reduction by factor up to 5.5 can be achieved for common detector sizes. The image

Spectroscopic investigations of hard x-ray emission from 120 ps laser-produced plasmas at intensities near 1017 W cm-2

International Nuclear Information System (INIS)

Dunn, J.; Young, B.K.F.; Osterheld, A.L.; Foord, M.E.; Walling, R.S.; Stewart, R.E.; Faenov, A.Y.

1995-11-01

Spectroscopic investigations of the x-ray emission of plasmas heated by 120 ps, frequency doubled pulses from the JANUS Nd: glass laser are presented. High Z K-shell spectra emitted from slab targets heated to near 10 17 W cm -2 intensity are investigated. High resolution (γ/Δγ>5000) x-ray spectra of multicharged ions of H-like Ti, Co, Ni, Cu, and also H-like Sc in the spectral range 1.5--3.0 angstrom are obtained in single laser shots using a spherically bent Mica crystal spectrograph with a 186 mm radius of curvature. The spectra- have one dimensional spatial resolution of about 25μm and indicate that the size of the emission zone of the resonance, transitions is 2 keV and density∼10 22 cm -3 . These experiments demonstrate that with modest laser energy, plasmas heated by high-intensity 120 ps lasers provide a very bright source of hard ∼8 keV x-ray emission

Measurements of x-rays and γ-rays from stopped kaons

International Nuclear Information System (INIS)

Godfrey, G.L.

1975-01-01

Intensities of x rays and γ rays from negative kaons stopped in elements, pure isotopes, and some compounds ranging from Z = 2 through Z = 92 have been measured. Included were x rays from K - atoms, Σ - atoms, and π - atoms. Also some nuclear γ rays associated with the stopped kaons were observed. The kaonic x-ray intensities for low n, Δn = 1 transitions, varied from .1 to .5 x rays/K/sub stop/ and showed a remarkable oscillation as Z changed. Peaks occurred near elements with closed electron shells. Within experimental accuracy, isotopes of the same elements yielded equal intensities. By searching for μ - from K - → μ - anti ν it was concluded that less than or equal to 5 percent of the stopped kaons decayed before nuclear capture in those elements studied. A cascade calculation was performed that reasonably reproduced the Δn = 1 intensities but gave Δn = 2 intensities high by a factor of 2. Initial kaon distributions in n = 30 proportional to (2l + 1) out to some l/sub max/ were used to begin the cascade. The value of l/sub max/ changed with Z. It is suggested that l/sub max/ might be related to an impact parameter picture with the lever arm equal to one-half the distance between the atoms in their lattice. (U.S.)

How to decrease bronchopulmonary dysplasia in your neonatal intensive care unit today and "tomorrow".

Science.gov (United States)

Nelin, Leif D; Bhandari, Vineet

2017-01-01

Bronchopulmonary dysplasia, or BPD, is the most common chronic lung disease in infants. Genetic predisposition and developmental vulnerability secondary to antenatal and postnatal infections, compounded with exposure to hyperoxia and invasive mechanical ventilation to an immature lung, result in persistent inflammation, culminating in the characteristic pulmonary phenotype of BPD of impaired alveolarization and dysregulated vascularization. In this article, we highlight specific areas in current management, and speculate on therapeutic strategies that are on the horizon, that we believe will make an impact in decreasing the incidence of BPD in your neonatal intensive care units.

26Al in iron meteorites and the constancy of comic ray intensity in the past

International Nuclear Information System (INIS)

Hampel, W.; Schaeffer, O.A.

1979-01-01

Cosmic-ray-produced 26 Al in iron meteorites has been measured by low-level γγ-coincidence counting. The 26 Al activities, in dpm/kg, are: Aroos 3.0 +- 1.0, Braunau 2.6 +- 0.5, Kayakent 4.6 +- 1.5, N'Goureyma 4.4 +- 1.1, Okahandja 3.6 +- 0.9, Treysa 4.0 +- 0.5. Exposure ages based on 26 Al/ 21 Ne are in agreement, within experimental error (+-20%) , with those based on 36 Cl/ 36 Ar and 39 Ar/ 38 Ar but the ages based on 40 K/ 41 K are higher by about 50%. The difference in exposure ages is probably caused by a real change of the cosmic ray intensity in the inner solar system. (Auth.)

Energy dependence of photon-induced L shell x-ray intensity ratios in Ta and W

Energy Technology Data Exchange (ETDEWEB)

Shatendra, K; Allawadhi, K L; Sood, B S

1984-02-01

The L shell x-ray intensity ratios have been measured for the elements Ta and W by photoionization of L shell electrons in the photon energy region 14 <= E <= 44 keV. The experimental results are compared with those calculated at the photon energies used in the present measurements. The measured values show fairly good agreement with the calculated values within the experimental uncertainties. 11 references, 7 figures.

Neutron monitor latitude survey of cosmic ray intensity during the 1986/1987 solar minimum

International Nuclear Information System (INIS)

Moraal, H.; Potgieter, M.S.; Stoker, P.H.; van der Walt, A.J.

1989-01-01

A latitude survey of the cosmic ray intensity at sea level was conducted during the 1986/1987 solar minimum period on commercial vessels of the South African Marine Corporation (SAFMARINE). The results show that the differential response function for the 1986/1987 solar minimum agrees well with that measured in 1965. Both these response functions are significantly lower than those for 1976 and 1954. This result supports the 22-year modulation cycle as predicted, for example, by models including drift effects of the charged cosmic ray particles in the large-scale interplanetary magnetic field. A crossover of the spectra at rigidities of about 7 GV was also observed. Such a crossover is necessary to explain both the stationary neutron monitor counting rates and the lower-energy balloon and space observations in consecutive solar cycles. copyright American Geophysical Union 1989

Investigation of Bragg reflections in α NbDsub(x) under hydrostatic pressure by γ ray diffraction

International Nuclear Information System (INIS)

Blaschko, O.; Klemencic, R.; Weinzierl, P.; Eder, O.J.

1978-01-01

Bragg reflections of NbDsub(x) single crystals in the α phase were studied under hydrostatic pressure using γ ray diffraction. The integrated intensity of the (211) reflection decreases by - 1.5 +- 0.2%/kbar and - 0.7 +- 0.1%/kbar in NbDsub(0.04) and NbDsub(0.02) respectively. The (200), (110) and (222) reflections show no change of intensity under hydrostatic pressure. In a pure Nb crystal no decrease of the intensity of the (211) reflection was found under hydrostatic pressure. (author)

Calculated L-shell x-ray line intensities for proton and helium ion impact

International Nuclear Information System (INIS)

Cohen, D.D.; Harrigan, M.

1986-01-01

Theoretical L-shell X-ray line intensities have been calculated for proton and helium bombardment of atoms from nickel (Z 2 = 28) to curium (Z 2 = 96). The ionization cross sections for the three L subshells were obtained from the recent calculations by Cohen and Harrigan in the ECPSSR theory, which uses the plane-wave Born approximation (PWBA) with corrections for energy loss (E), Coulomb deflection (C), perturbed-stationary-state (PSS), and relativistic (R) effects. The fluorescence yields and Coster-Kronig transition probabilities were taken from M. O. Krause (Phys. Chem. Ref. Data 8, 307 (1979)) and the L-subshell emission rates from S. I. Salem, S. L. Panosian, and R. A. Krause (Atomic Data and Nuclear Data Tables 14, 91 (1974)). The line intensities Ll, Lα, Leta, Lβ 1 to Lβ 6 , Lβ/sub 9,10/, and Lγ 1 to Lgg 6 are tabulated for selected ion energies from 0.2 to 10 MeV

Measurement of angular distributions of K x-ray intensity of Ti and Cu thick targets following impact of 10–25 keV electrons

Energy Technology Data Exchange (ETDEWEB)

Singh, Bhupendra; Kumar, Sunil; Prajapati, Suman; Singh, Bhartendu K. [Atomic Physics Laboratory, Department of Physics, Institute of Science, Banaras Hindu University, Varanasi 221005 (India); Llovet, Xavier [Scientific and Technological Centers, Universitat de Barcelona, Lluís Solé i Sabarís 1-3, 08028 Barcelona (Spain); Shanker, R., E-mail: shankerorama@gmail.com [Atomic Physics Laboratory, Department of Physics, Institute of Science, Banaras Hindu University, Varanasi 221005 (India)

2017-04-15

Highlights: • New results on the angular distributions of relative intensities of K-X-rays lines of Ti and Cu thick targets under electron bombardment are reported. • An increase of relative intensity of Kα and Kβ X-ray lines has been found to be about 60–70% in the detection range θ = 105{sup 0}–165{sup 0}. • There is a slight impact energy dependence of Cu Kα X-ray line. • A reasonable agreement between experimental and PENELOPE MC Calculations are obtained. - Abstract: We present new results on angular distributions of the relative intensity of K{sub α} and K{sub β} x-ray lines of thick targets of Ti (Z = 22) and Cu (Z = 29) pure elements following impact of 10–25 keV electrons. The angular measurements of the K x-radiations were accomplished by rotating the target surface with respect to the electron beam direction. The x-rays emerging from the target surface in reflection mode were detected by an energy dispersive Si P-I-N photodiode detector. The resulting variation of the relative intensity of the characteristic lines as a function of angle of detection and impact energy has been found to be anisotropic and it is considered to arise due to change in path lengths at a given incidence angle α for the photons generated by direct as well as by indirect K shell ionization processes. The measured angular variations of relative intensity of K{sub α} and K{sub β} x-ray lines of both targets are found to increase by about 60–70% in going from θ = 105{sup 0} to 165{sup 0} at a given impact energy; however there is a slight indication of impact energy dependence of Cu K{sub α} x-ray line as also noted by the earlier workers. We compare the experimental results with those obtained by Monte Carlo simulations using PENELOPE calculations; the agreement between experiment and theory is found to be satisfactory within uncertainties involved in the measurements and the theoretical results.

Local Times of Galactic Cosmic Ray Intensity Maximum and Minimum in the Diurnal Variation

Directory of Open Access Journals (Sweden)

Su Yeon Oh

2006-06-01

Full Text Available The Diurnal variation of galactic cosmic ray (GCR flux intensity observed by the ground Neutron Monitor (NM shows a sinusoidal pattern with the amplitude of 1sim 2 % of daily mean. We carried out a statistical study on tendencies of the local times of GCR intensity daily maximum and minimum. To test the influences of the solar activity and the location (cut-off rigidity on the distribution in the local times of maximum and minimum GCR intensity, we have examined the data of 1996 (solar minimum and 2000 (solar maximum at the low-latitude Haleakala (latitude: 20.72 N, cut-off rigidity: 12.91 GeV and the high-latitude Oulu (latitude: 65.05 N, cut-off rigidity: 0.81 GeV NM stations. The most frequent local times of the GCR intensity daily maximum and minimum come later about 2sim3 hours in the solar activity maximum year 2000 than in the solar activity minimum year 1996. Oulu NM station whose cut-off rigidity is smaller has the most frequent local times of the GCR intensity maximum and minimum later by 2sim3 hours from those of Haleakala station. This feature is more evident at the solar maximum. The phase of the daily variation in GCR is dependent upon the interplanetary magnetic field varying with the solar activity and the cut-off rigidity varying with the geographic latitude.

Reduction of intensity variations on a photovoltaic array with compound parabolic concentrators

Science.gov (United States)

Greenman, P.; Ogallagher, J.; Winston, R.; Costogue, E.

1979-01-01

The reduction of nonuniformities in the intensity distribution of light focused on a photovoltaic array by a compound parabolic concentrator is investigated. The introduction of small distortions into the surfaces of the reflector in order to diffuse the incident collimated light to fill the angular acceptance of the concentrator is calculated by means of ray tracing to decrease the irradiance nonuniformity at the cost of a lowered effective concentration of the concentrator. Measurements of the intensity distribution on a scale test model in terrestrial sunlight with corrugated aluminized mylar reflectors are shown to be in good agreement with the ray tracing results. A two-stage concentrator consisting of a focusing primary and a nonimaging secondary is also shown to result in a fairly uniform intensity distribution except in the case of a 4-deg incidence angle, which may be corrected by the introduction of distortions into one or both concentration stages.

Alteration of UV primary fluorescence of vital tumor cells following irradiation with neutrons and gamma rays

International Nuclear Information System (INIS)

Merkle, K.

1980-01-01

The change of UV primary fluorescence intensity of vital unstained cells of Ehrlich ascites carcinoma after 60 Co-gamma and neutron irradiation was investigated. The mean neutron energy was 6.2 MeV. Fluorescence intensity was detected using impulse cytophotometry. The UV intensity of single cells was measured in the spectral range from 300-400 nm. An monotonous increase of dose-effect curves and a maximum at 3.5 Gy (neutrons) and 30 Gy (γ-rays) was obtained. The first relevant increase of fluorescence intensity was detected at 0.4 Gy (neutrons) and 0.75 Gy (γ-rays). Factors influencing the increase and decrease of primary fluorescence behavior of vital cells are discussed. (author)

Scaling of Pressure with Intensity in Laser-Driven Shocks and Effects of Hot X-Ray Preheat

International Nuclear Information System (INIS)

Colvin, Jeffrey D.; Kalantar, Daniel H.

2006-01-01

To drive shocks into solids with a laser we either illuminate the material directly, or to get higher pressures, illuminate a plastic ablator that overlays the material of interest. In both cases the illumination intensity is low, <<1013 W/cm2, compared to that for traditional laser fusion targets. In this regime, the laser beam creates and interacts with a collisional, rather than a collisionless, plasma. We present scaling relationships for shock pressure with intensity derived from simulations for this low-intensity collisional plasma regime. In addition, sometimes the plastic-ablator targets have a thin flash-coating of Al on the plastic surface as a shine-through barrier; this Al layer can be a source of hot x-ray preheat. We discuss how the preheat affects the shock pressure, with application to simulating VISAR measurements from experiments conducted on various lasers on shock compression of Fe

Scaling of Pressure with Intensity in Laser-Driven Shocks and Effects of Hot X-ray Preheat

International Nuclear Information System (INIS)

Colvin, J D; Kalantar, D H

2005-01-01

To drive shocks into solids with a laser we either illuminate the material directly, or to get higher pressures, illuminate a plastic ablator that overlays the material of interest. In both cases the illumination intensity is low, 13 W/cm 2 , compared to that for traditional laser fusion targets. In this regime, the laser beam creates and interacts with a collisional, rather than a collisionless, plasma. We present scaling relationships for shock pressure with intensity derived from simulations for this low-intensity collisional plasma regime. In addition, sometimes the plastic-ablator targets have a thin flashcoating of Al on the plastic surface as a shine-through barrier; this Al layer can be a source of hot x-ray preheat. We discuss how the preheat affects the shock pressure, with application to simulating VISAR measurements from experiments conducted on various lasers on shock compression of Fe

Estimation of cerium and lanthanum content in core material of high intensity carbon arc electrodes by x-ray fluorescence method

International Nuclear Information System (INIS)

Nagpal, K.C.; Bhavalkar, R.H.

1977-01-01

The X-ray fluorescence method has been used to determine the weight percentages of cerium and lanthanum in the core material of high intensity carbon arc electrodes from the calibration curves plotted between the weight percentages of these elements and the peak-intensity ratios of CeLsub(α1), and LaLsub(α1) peaks to the neighbouring peak SnLsub(α1) due to an internal standard element. (author)

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

International Nuclear Information System (INIS)

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

2007-01-01

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

Response function of NaI(Tl) detectors and multiple backscattering of gamma rays in aluminium

International Nuclear Information System (INIS)

Sabharwal, Arvind D.; Singh, Manpreet; Singh, Bhajan; Sandhu, B.S.

2008-01-01

The response function, converting the observed pulse-height distribution of a NaI(Tl) detector to a true photon spectrum, is obtained experimentally with the help of an inverse matrix approach. The energy of gamma-ray photons continuously decreases as the number of scatterings increases in a sample having finite dimensions when one deals with the depth of the sample. The present experiments are undertaken to study the effect of target thickness on intensity distribution of gamma photons multiply backscattered from an aluminium target. A NaI(Tl) gamma-ray detector detects the photons backscattered from the aluminium target. The subtraction of analytically estimated singly scattered distribution from the observed intensity distribution (originating from interactions of primary gamma-ray photons with the target) results in multiply backscattered events. We observe that for each incident gamma photon energy, the number of multiply backscattered photons increases with increase in target thickness and then saturates at a particular target thickness called the saturation thickness (depth). Saturation thickness for multiply backscattering of gamma photons is found to decrease with increase in energy of incident gamma-ray photons

Sustained, Low-Intensity Exercise Achieved by a Dynamic Feeding System Decreases Body Fat in Ponies.

Science.gov (United States)

de Laat, M A; Hampson, B A; Sillence, M N; Pollitt, C C

2016-09-01

Obesity in horses is increasing in prevalence and can be associated with insulin insensitivity and laminitis. Current treatment strategies for obesity include dietary restriction and exercise. However, whether exercise alone is effective for decreasing body fat is uncertain. Our hypothesis was that twice daily use of a dynamic feeding system for 3 months would induce sustained, low-intensity exercise thereby decreasing adiposity and improving insulin sensitivity (SI). Eight, university-owned, mixed-breed, adult ponies with body condition scores (BCS) ≥5/9 were used. Two treatments ("feeder on" or "feeder off") were administered for a 3-month period by a randomized, crossover design (n = 4/treatment). An interim equilibration period of 6 weeks at pasture separated the 2 study phases. Measurements of body mass (body weight, BCS, cresty neck score [CrNS], and morphometry), body fat (determined before and after the "feeder on" treatment only), triglycerides, and insulin sensitivity (SI; combined glucose-insulin test) were undertaken before and after treatments. The dynamic feeding system induced a 3.7-fold increase in the daily distance travelled (n = 6), compared to with a stationary feeder, which significantly decreased mean BCS (6.53 ± 0.94 to 5.38 ± 1.71), CrNS (2.56 ± 1.12 to 1.63 ± 1.06) and body fat (by 4.95%). An improvement in SI did not occur in all ponies. A dynamic feeding system can be used to induce sustained (daily), low-intensity exercise that promotes weight loss in ponies. However, this exercise may not be sufficient to substantially improve SI. Copyright © 2016 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.

X-ray radiation damage of organic semiconductor thin films during grazing incidence diffraction experiments

Energy Technology Data Exchange (ETDEWEB)

Neuhold, A., E-mail: alfred.neuhold@tugraz.at [Institute of Solid State Physics, Graz University of Technology, Graz (Austria); Novak, J.; Flesch, H.-G.; Moser, A.; Djuric, T. [Institute of Solid State Physics, Graz University of Technology, Graz (Austria); Grodd, L.; Grigorian, S.; Pietsch, U. [Institute of Physics, University Siegen (Germany); Resel, R. [Institute of Solid State Physics, Graz University of Technology, Graz (Austria)

2012-08-01

Since modern synchrotrons with highly intense X-ray beams are in use to investigate organic materials, the stability of soft matter materials during beam exposure is a crucial issue. Grazing incidence X-ray diffraction and specular X-ray reflectivity measurements were performed on thin films of organic semiconducting materials, like poly(3-hexylthiophene) (P3HT), sexithiophene and pentacene. These films were irradiated with an average flux density between 10{sup 15} and 10{sup 16} photons/(s mm{sup 2}) and evidenced a different stability in synchrotron X-ray radiation. The semi-crystalline P3HT showed a clear intensity decrease of the 1 0 0 Bragg peak and 0 2 0 Bragg peak compared to the rather stable diffraction features of the molecular crystals sexithiophene and pentacene. The difference in synchrotron X-ray radiation stability is explained by the interaction of the X-ray beam with the individual chemical components in the molecules as well as by the different crystallinities of the materials. Furthermore, the semi-crystalline P3HT film exhibited an increase of film thickness after irradiation and the surface roughness slightly decreased. To summarize, this study shows a strong influence of synchrotron X-ray radiation to specific organic thin films like e.g. P3HT, while others like pentacene and sexithiophene are observed as quite stable.

Theoretical analysis of the background intensity distribution in X-ray Birefringence Imaging using synchrotron bending-magnet radiation

Science.gov (United States)

Sutter, John P.; Dolbnya, Igor P.; Collins, Stephen P.; Harris, Kenneth D. M.; Edwards-Gau, Gregory R.; Palmer, Benjamin A.

2015-04-01

In the recently developed technique of X-ray Birefringence Imaging, molecular orientational order in anisotropic materials is studied by exploiting the birefringence of linearly polarized X-rays with energy close to an absorption edge of an element in the material. In the experimental setup, a vertically deflecting high-resolution double-crystal monochromator is used upstream from the sample to select the appropriate photon energy, and a horizontally deflecting X-ray polarization analyzer, consisting of a perfect single crystal with a Bragg reflection at Bragg angle of approximately 45°, is placed downstream from the sample to measure the resulting rotation of the X-ray polarization. However, if the experiment is performed on a synchrotron bending-magnet beamline, then the elliptical polarization of the X-rays out of the electron orbit plane affects the shape of the output beam. Also, because the monochromator introduces a correlation between vertical position and photon energy to the X-ray beam, the polarization analyzer does not select the entire beam, but instead selects a diagonal stripe, the slope of which depends on the Bragg angles of the monochromator and the polarization analyzer. In the present work, the final background intensity distribution is calculated analytically because the phase space sampling methods normally used in ray traces are too inefficient for this setup. X-ray Birefringence Imaging data measured at the Diamond Light Source beamline B16 agree well with the theory developed here.

Theoretical analysis of the background intensity distribution in X-ray Birefringence Imaging using synchrotron bending-magnet radiation

Energy Technology Data Exchange (ETDEWEB)

Sutter, John P., E-mail: john.sutter@diamond.ac.uk; Dolbnya, Igor P.; Collins, Stephen P. [Diamond Light Source Ltd., Chilton, Didcot, Oxfordshire OX11 0DE (United Kingdom); Harris, Kenneth D. M.; Edwards-Gau, Gregory R. [School of Chemistry, Cardiff University, Park Place, Cardiff CF10 3AT, Wales (United Kingdom); Palmer, Benjamin A. [Department of Structural Biology, Weizmann Institute of Science, 234 Herzl St., Rehovot 7610001 (Israel)

2015-04-28

In the recently developed technique of X-ray Birefringence Imaging, molecular orientational order in anisotropic materials is studied by exploiting the birefringence of linearly polarized X-rays with energy close to an absorption edge of an element in the material. In the experimental setup, a vertically deflecting high-resolution double-crystal monochromator is used upstream from the sample to select the appropriate photon energy, and a horizontally deflecting X-ray polarization analyzer, consisting of a perfect single crystal with a Bragg reflection at Bragg angle of approximately 45°, is placed downstream from the sample to measure the resulting rotation of the X-ray polarization. However, if the experiment is performed on a synchrotron bending-magnet beamline, then the elliptical polarization of the X-rays out of the electron orbit plane affects the shape of the output beam. Also, because the monochromator introduces a correlation between vertical position and photon energy to the X-ray beam, the polarization analyzer does not select the entire beam, but instead selects a diagonal stripe, the slope of which depends on the Bragg angles of the monochromator and the polarization analyzer. In the present work, the final background intensity distribution is calculated analytically because the phase space sampling methods normally used in ray traces are too inefficient for this setup. X-ray Birefringence Imaging data measured at the Diamond Light Source beamline B16 agree well with the theory developed here.

Study of X-rays and nuclear gamma -rays in muonic thallium

CERN Document Server

Backe, H; Jahnke, U; Kankeleit, E; Pearce, R M; Petitjean, C; Schellenberg, L; Schneuwly, H; Schröder, W U; Walter, H K; Zehnder, A

1972-01-01

Energies and intensities of muonic X-rays, nuclear gamma -rays and mu -capture gamma -rays were measured in natural muonic thallium with Ge (Li) detectors. The absolute intensities of higher mu X-rays were reproduced by a cascade calculation starting with a statistical population at n=20 including K-, L- and M-conversion. The electron screening effect was deduced from energies of higher mu X-rays. Eight prompt nuclear gamma -rays were found. This excitation explains the anomalous intensity ratios of the 2p-1s and 3d-2p fine structure components. From the nuclear gamma -rays of the first excited states were deduced: the magnetic h.f. splittings, muonic isomer shifts E2/M1 mixing ratios and the half-life in the presence of the muon in /sup 205/Tl. Evidence for a magnetic nuclear polarization was found. An isotope shift of Delta E=10.35+or-0.25 keV was measured for the 1s/sub 1/2/ state which is compared with data from optical spectroscopy. From an analysis of the time distribution of delayed gamma -rays from mu...

Time-dependent, x-ray spectral unfolds and brightness temperatures for intense Li+ ion beam-driven hohlraums

International Nuclear Information System (INIS)

Fehl, D.L.; Chandler, G.A.; Biggs, F.; Dukart, R.J.; Moats, A.R.; Leeper, R.J.

1996-01-01

X-ray-producing hohlraums are being studied as indirect drives for Inertial Confinement Fusion targets. In a 1994 target series on the PBFAII accelerator, cylindrical hohlraum targets were heated by an intense Li + ion beam and viewed by an array of 13 time-resolved, filtered x-ray detectors (XRDs). The UFO unfold code and its suite of auxiliary functions were used extensively in obtaining time- resolved x-ray spectra and radiation temperatures from this diagnostic. UFO was also used to obtain fitted response functions from calibration data, to simulate data from blackbody x-ray spectra of interest, to determine the suitability of various unfolding parameters (e.g., energy domain, energy partition, smoothing conditions, and basis functions), to interpolate the XRD signal traces, and to unfold experimental data. The simulation capabilities of the code were useful in understanding an anomalous feature in the unfolded spectra at low photon energies (≤ 100 eV). Uncertainties in the differential and energy-integrated unfolded spectra were estimated from uncertainties in the data. The time-history of the radiation temperature agreed well with independent calculations of the wall temperature in the hohlraum

Time-dependent, x-ray spectral unfolds and brightness temperatures for intense Li+ ion beam-driven hohlraums

International Nuclear Information System (INIS)

Fehl, D.L.; Chandler, G.A.; Biggs, F.; Dukart, R.J.; Moats, A.R.; Leeper, R.J.

1997-01-01

X-ray-producing hohlraums are being studied as indirect drives for inertial confinement fusion targets. In a 1994 target series on the PBFAII accelerator, cylindrical hohlraum targets were heated by an intense Li + ion beam and viewed by an array of 13 time-resolved, filtered x-ray detectors (XRDs). The unfold operator (UFO) code and its suite of auxiliary functions were used extensively in obtaining time-resolved x-ray spectra and radiation temperatures from this diagnostic. The UFO was also used to obtain fitted response functions from calibration data, to simulate data from blackbody x-ray spectra of interest, to determine the suitability of various unfolding parameters (e.g., energy domain, energy partition, smoothing conditions, and basis functions), to interpolate the XRD signal traces, and to unfold experimental data. The simulation capabilities of the code were useful in understanding an anomalous feature in the unfolded spectra at low photon energies (≤100 eV). Uncertainties in the differential and energy-integrated unfolded spectra were estimated from uncertainties in the data. The time endash history of the radiation temperature agreed well with independent calculations of the wall temperature in the hohlraum. copyright 1997 American Institute of Physics

Windowless microfluidic platform based on capillary burst valves for high intensity x-ray measurements

International Nuclear Information System (INIS)

Vig, Asger Laurberg; Enevoldsen, Nikolaj; Thilsted, Anil Haraksingh; Eriksen, Johan; Kristensen, Anders; Haldrup, Kristoffer; Feidenhans'l, Robert; Nielsen, Martin Meedom

2009-01-01

We propose and describe a microfluidic system for high intensity x-ray measurements. The required open access to a microfluidic channel is provided by an out-of-plane capillary burst valve (CBV). The functionality of the out-of-plane CBV is characterized with respect to the diameter of the windowless access hole, ranging from 10 to 130 μm. Maximum driving pressures from 22 to 280 mbar corresponding to refresh rates of the exposed sample from 300 Hz to 54 kHz is demonstrated. The microfluidic system is tested at beamline ID09b at the ESRF synchrotron radiation facility in Grenoble, and x-ray scattering measurements are shown to be feasible and to require only very limited amounts of sample, <1 ml/h of measurements without recapturing of sample. With small adjustments of the present chip design, scattering angles up to 30 deg. can be achieved without shadowing effects and integration on-chip mixing and spectroscopy appears straightforward.

X-ray intensity fluctuation spectroscopy in the energy range from 1 to 4 keV

Energy Technology Data Exchange (ETDEWEB)

Retsch, C.C.

2001-06-01

X-ray intensity fluctuation spectroscopy was developed in the energy range of 1 to 4 keV and was used to study complex sample structures and dynamics in a liquid-crystal - aerosil dispersion. The advantages of a focusing versus a nonfocusing setup were explored, and the effects of using X-ray energies near absorption edges were investigated to enhance the capabilities of the method. It was found that even though excellent real space resolution and an increase in flux density can be gained from a Fresnel zone plate focusing setup, this usually comes at the expense of speckle contrast. At absorption edges, the speckle contrast is dominated by the imaginary part of the sample's index of refraction and therefore varies in a way similar to the total transmitted intensity. Employing these results, the dynamics of a dispersion of low-density silica aerosil in octylcyanobiphenyl (8CB) were studied. It was found that the known cross-over behavior of 8CB - aerosil samples towards the 3d-XY universality class should be understood as the coupling of the aerosil-gel dynamics to the dynamics of the director fluctuations in the liquid-crystal. This work indicates that the aerosil-gel mimics and dampens these director fluctuations and thus, by suppressing the director fluctuations, achieves a pure 3d-XY system. (orig.)

Analysis of the Relationship Between the Solar X-Ray Radiation Intensity and the D-Region Electron Density Using Satellite and Ground-Based Radio Data

Science.gov (United States)

Nina, Aleksandra; Čadež, Vladimir M.; Bajčetić, Jovan; Mitrović, Srdjan T.; Popović, Luka Č.

2018-04-01

Increases in the X-ray radiation that is emitted during a solar X-ray flare induce significant changes in the ionospheric D region. Because of the numerous complex processes in the ionosphere and the characteristics of the radiation and plasma, the causal-consequential relationship between the X-ray radiation and ionospheric parameters is not easily determined. In addition, modeling the ionospheric D-region plasma parameters is very difficult because of the lack of data for numerous time- and space-dependent physical quantities. In this article we first give a qualitative analysis of the relationship between the electron density and the recorded solar X-ray intensity. After this, we analyze the differences in the relationships between the D-region response and various X-ray radiation properties. The quantitative study is performed for data observed on 5 May 2010 in the time period between 11:40 UT - 12:40 UT when the GOES 14 satellite detected a considerable X-ray intensity increase. Modeling the electron density is based on characteristics of the 23.4 kHz signal emitted in Germany and recorded by the receiver in Serbia.

Cosmic ray modulation

Science.gov (United States)

Agarwal Mishra, Rekha; Mishra, Rajesh Kumar

2016-07-01

Propagation of cosmic rays to and inside the heliosphere, encounter an outward moving solar wind with cyclic magnetic field fluctuation and turbulence, causing convection and diffusion in the heliosphere. Cosmic ray counts from the ground ground-based neutron monitors at different cut of rigidity show intensity changes, which are anti-correlated with sunspot numbers. They also lose energy as they propagate towards the Earth and experience various types of modulations due to different solar activity indices. In this work, we study the first three harmonics of cosmic ray intensity on geo-magnetically quiet days over the period 1965-2014 for Beijing, Moscow and Tokyo neutron monitoring stations located at different cut off rigidity. The amplitude of first harmonic remains high for low cutoff rigidity as compared to high cutoff rigidity on quiet days. The diurnal amplitude significantly decreases during solar activity minimum years. The diurnal time of maximum significantly shifts to an earlier time as compared to the corotational direction having different cutoff rigidities. The time of maximum for first harmonic significantly shifts towards later hours and for second harmonic it shifts towards earlier hours at low cutoff rigidity station as compared to the high cut off rigidity station on quiet days. The amplitude of second/third harmonics shows a good positive correlation with solar wind velocity, while the others (i.e. amplitude and phase) have no significant correlation on quiet days. The amplitude and direction of the anisotropy on quiet days does not show any significant dependence on high-speed solar wind streams for these neutron monitoring stations of different cutoff rigidity threshold. Keywords: cosmic ray, cut off rigidity, quiet days, harmonics, amplitude, phase.

Short-time X-ray diffraction with an efficient-optimized, high repetition-rate laser-plasma X-ray-source

International Nuclear Information System (INIS)

Kaehle, Stephan

2009-01-01

This thesis deals with the production and application of ultrashort X-ray pulses. In the beginning different possibilities for the production of X-ray pulses with pulse durations of below one picosecond are presented, whereby the main topic lies on the so called laser-plasma X-ray sources with high repetition rate. In this case ultrashort laser pulses are focused on a metal, so that in the focus intensities of above 10 16 W/cm 2 dominate. In the ideal case in such way ultrafast electrons are produced, which are responsible for line radiation. In these experiments titanium K α radiation is produced, thes photons possess an energy of 4.51 keV. For the efficient production of line radiation here the Ti:Sa laser is optimized in view of the laser energy and the pulse shape and the influence of the different parameters on the K α production systematically studied. The influences of laser intensity, system-conditioned pre-pulses and of phase modulation are checked. It turns out that beside the increasement of the K α radiation by a suited laser intensity a reduction of the X-ray background radiation is of deciding importance for the obtaining of clear diffraction images. This background radiation is mainly composed of bremsstrahlung. It can be suppressed by the avoidance of intrinsic pre-pulses and by means of 2nd-order phase modulation. By means of optical excitation and X-ray exploration experiments the production of acoustic waves after ultrashort optical excitation in a 150 nm thick Ge(111) film on Si(111) is studied. These acoustic waves are driven by thermal (in this time scale time-independent) and electronic (time dependent) pressure amounts. As essential results it turns out that the relative amount of the electronic pressure increases with decreasing excitation density [de

Modeling Relativistic Electron Precipitation Bremsstrahlung X-Ray Intensities at 10-100 km Manned Vehicle Altitudes

Science.gov (United States)

Krause, L. Habsh; Gilchrist, B. E.; Nishikawa, Ken-Ichi

2013-01-01

Relativisitic electron precipitation (REP) events occur when beams or bunches of relativistic electrons of magnetospheric origin enter the Earth's atmosphere, typically at auroral latitudes. REP events are associated with a variety of space weather effects, including production of transitional and bremsstrahlung radiation, catalytic depletion of stratospheric ozone, and scintillation of transionospheric radio waves. This study examines the intensities of x-rays produced at airliner, manned balloon, and space reuseable launch vehicles (sRLVs). The monoenergetic beam is modeled in cylindrical symetry using the paraxial ray equation. Bremsstrahlung photon production is calculated using the traditional Sauter-Elwert cross-section, providing x-ray emission spectra differential in energy and angle. Attenuation is computed for a plane-stratified standard atmosphere, and the loss processes include photoionization, Rayleigh and Compton scattering, electron-positron pair production, and photonuclear interaction. Peak altitudes of electron energy deposition and bremsstrahlung x-ray production were calculated for beams of energies from 1 MeV through 100 MeV. The altitude peak of bremsstrahlung deposition was consistently and significantly lower that that of the electron deposition due to the longer mean free paths of x-rays compared to electrons within the atmosphere. For example, for a nadir-directed monoenergetic 5 MeV beam, the peak deposition altitude was calculated to be 42 km, but the resulting bremsstrahlung deposition peaked at 25 km. This has implications for crew and passenger safety, especially with the growth of the space tourism industry. A survey of results covering the 1-100 MeV spectrum for the three altitude ranges of interest will be presented.

X-ray detector for a panoramic X-ray unit

Energy Technology Data Exchange (ETDEWEB)

Cowell, D; Ensslin, F H

1976-01-15

The discovery deals with an X-ray detector suitable for the controlling of panoramic X-ray systems. It consists of a fluorescent image screen and a semiconductor photo cell. The output signal of the detector is proportional to the intensity of the X-radiation and the response time is large enough to follow the change of amplitude of the contours of the modulated X radiation. The detector with band-pass filter regulates, via a control system, the moving rate of the X-ray source and of the film opposite it in dependence of the intensity, so that a uniform exposure is ensured.

Rapid X-ray and optical variability in the X-ray selected BL Lacertae object IE 1402.3 + 0416

International Nuclear Information System (INIS)

Giommi, P.; Barr, P.; Gioia, I.M.; Maccacaro, T.; Schild, R.; Harvard-Smithsonian Center for Astrophysics, Cambridge)

1986-01-01

Results from X-ray and optical observations of the X-ray-discovered BL Lac object 1E 1402.3 + 0416 are presented, where the X-ray measurements were carried out with the Channel Multiplier Array (CMA) and Medium Energy experiment (ME) detectors on board Exosat. These measurements revealed an intensity decrease by a factor of two on a time scale of a few hours. At maximum flux, the source was significantly greater than at the time of the Einstein Image Proportional Counter (IPC) discovery observation. The 2-6 keV X-ray spectrum was determined by the ME experiment, and IPC, HRI, and CMA data were subsequently compared. The source varied over the years by a factor of five; its brightest state was within the last three years. It is noted that a redshift greater than 0.2 would require that anisotropic emission mechanisms be invoked. 18 references

Future prospect of the research study using intense and bright synchrotron radiation in VUV and soft x-ray region

International Nuclear Information System (INIS)

Tanaka, Kenichiro; Miyahara, Tsuneaki

1987-02-01

This report is the summary of the contents of the study meeting 'Future prospect of the research study using intense and bright synchrotron radiation in VUV and soft x-ray region' sponsored by PF, held on October 20 and 21, 1986. This study meeting was held by inviting those who are particularly interested in the basic field among the users of VUV and soft x-ray region, and the research on the application field was excluded. The objective of the discussion of this study meeting was to talk about the dream that if a high luminance light source which is 100 - 1000 times more intense in terms of luminous flux intensity is completed, what can we do with it. Three sessions on the themes 'How the existing research fields will develop', 'What the possible new research fields are' and 'Comment from the technical aspect' were held. More than seven years elapsed since the beginning of construction of the Photon Factory. Many excellent results have been obtained. As of October, 1986, the beam lines available for experiment are 11, the themes of common utilization experiment in progress are 300, and the number of registered researchers exceeded 1000. The development of a new light emission source is to be undertaken. (Kako, I.)

Dosimetry of environmental radiations (cosmic ray)

International Nuclear Information System (INIS)

Yamasaki, Keizo

1978-01-01

Cosmic ray is dominant as environmental radiation, though the experimental determination made on cosmic ray doses is few in Japan. The free air ionization intensity at sea level due to cosmic ray has been estimated in the Bay of Wakasa, Japan, at middle geomagnetic latitude (25 deg. N), in October 1977. The ionization chambers used were two air and one argon types. Where the responses to cosmic and terrestrial gamma rays were equal, the ionization intensity due to cosmic ray was obtained by subtracting the ionization intensity due to terrestrial gamma ray from the total ionization intensity. As the terrestrial gamma ray, (1) U-238 series, Th-232 series, and K-40 in seawater, (2) K-40 in the material of a wooden ship, and (3) Rn-222 and its daughter products in the atmosphere were considered. The result of free air ionization due to cosmic ray with the argon chamber was slightly smaller than those with the other two air chambers; however, both were in good agreement within standard errors. (JPN.)

Thermally and optically stimulated luminescence correlated processes in X-ray irradiated KCl:Eu2+

International Nuclear Information System (INIS)

Chernov, V.; Melendrez Ao, R.; Piters, T.M.; Barboza-Flores, M.

2001-01-01

The effect of optical bleaching on thermoluminescence (TL) and thermal bleaching on optically stimulated luminescence (OSL) outputs in X-ray irradiated KCl : Eu 2+ have been investigated. The X-ray induced glow curves reveal three main peaks located at 370, 410 and 470 K. Illumination with 560 nm light leads to a drastic change of the TL glow curve. The 470 K peak is destroyed during bleaching. The other peaks initially increase in intensity and only after sufficiently long bleaching begin to decrease. After long-time bleaching, the TL peaks in X-ray irradiated crystals look like the TL peaks found in UV irradiated crystals. The effect of thermal bleaching on OSL is also very pronounced. The temperature dependencies show a step-by-step decrease of the OSL intensity correlated with the positions of the TL peaks. The result obtained shows that centers responsible for the TL peaks participate in OSL, but this participation seems not to be direct and is complicated by processes accompanying the F center bleaching

How to decrease bronchopulmonary dysplasia in your neonatal intensive care unit today and “tomorrow”

Science.gov (United States)

Nelin, Leif D.; Bhandari, Vineet

2017-01-01

Bronchopulmonary dysplasia, or BPD, is the most common chronic lung disease in infants. Genetic predisposition and developmental vulnerability secondary to antenatal and postnatal infections, compounded with exposure to hyperoxia and invasive mechanical ventilation to an immature lung, result in persistent inflammation, culminating in the characteristic pulmonary phenotype of BPD of impaired alveolarization and dysregulated vascularization. In this article, we highlight specific areas in current management, and speculate on therapeutic strategies that are on the horizon, that we believe will make an impact in decreasing the incidence of BPD in your neonatal intensive care units. PMID:28503300

GRAP, Gamma-Ray Level-Scheme Assignment

International Nuclear Information System (INIS)

Franklyn, C.B.

2002-01-01

1 - Description of program or function: An interactive program for allocating gamma-rays to an energy level scheme. Procedure allows for searching for new candidate levels of the form: 1) L1 + G(A) + G(B) = L2; 2) G(A) + G(B) = G(C); 3) G(A) + G(B) = C (C is a user defined number); 4) L1 + G(A) + G(B) + G(C) = L2. Procedure indicates intensity balance of feed and decay of each energy level. Provides for optimization of a level energy (and associated error). Overall procedure allows for pre-defining of certain gamma-rays as belonging to particular regions of the level scheme, for example, high energy transition levels, or due to beta- decay. 2 - Method of solution: Search for cases in which the energy difference between two energy levels is equal to a gamma-ray energy within user-defined limits. 3 - Restrictions on the complexity of the problem: Maximum number of gamma-rays: 999; Maximum gamma ray energy: 32000 units; Minimum gamma ray energy: 10 units; Maximum gamma-ray intensity: 32000 units; Minimum gamma-ray intensity: 0.001 units; Maximum number of levels: 255; Maximum level energy: 32000 units; Minimum level energy: 10 units; Maximum error on energy, intensity: 32 units; Minimum error on energy, intensity: 0.001 units; Maximum number of combinations: 6400 (ca); Maximum number of gamma-ray types : 127

A low free-parameter stochastic model of daily Forbush decrease indices

Science.gov (United States)

Patra, Sankar Narayan; Bhattacharya, Gautam; Panja, Subhash Chandra; Ghosh, Koushik

2014-01-01

Forbush decrease is a rapid decrease in the observed galactic cosmic ray intensity pattern occurring after a coronal mass ejection. In the present paper we have analyzed the daily Forbush decrease indices from January, 1967 to December, 2003 generated in IZMIRAN, Russia. First the entire indices have been smoothened and next we have made an attempt to fit a suitable stochastic model for the present time series by means of a necessary number of process parameters. The study reveals that the present time series is governed by a stationary autoregressive process of order 2 with a trace of white noise. Under the consideration of the present model we have shown that chaos is not expected in the present time series which opens up the possibility of validation of its forecasting (both short-term and long-term) as well as its multi-periodic behavior.

Modifying effects of low-intensity extremely high-frequency electromagnetic radiation on content and composition of fatty acids in thymus of mice exposed to X-rays.

Science.gov (United States)

Gapeyev, Andrew B; Aripovsky, Alexander V; Kulagina, Tatiana P

2015-03-01

The effects of extremely high-frequency electromagnetic radiation (EHF EMR) on thymus weight and its fatty acids (FA) content and FA composition in X-irradiated mice were studied to test the involvement of FA in possible protective effects of EHF EMR against ionizing radiation. Mice were exposed to low-intensity pulse-modulated EHF EMR (42.2 GHz, 0.1 mW/cm(2), 20 min exposure, 1 Hz modulation) and/or X-rays at a dose of 4 Gy with different sequences of the treatments. In 4-5 hours, 10, 30, and 40 days after the last exposure, the thymuses were weighed; total FA content and FA composition of the thymuses were determined on days 1, 10, and 30 using a gas chromatography. It was shown that after X-irradiation of mice the total FA content per mg of thymic tissue was significantly increased in 4-5 h and decreased in 10 and 30 days after the treatment. On days 30 and 40 after X-irradiation, the thymus weight remained significantly reduced. The first and tenth days after X-rays injury independently of the presence and sequence of EHF EMR exposure were characterized by an increased content of polyunsaturated FA (PUFA) and a decreased content of monounsaturated FA (MUFA) with unchanged content of saturated FA (SFA). Exposure of mice to EHF EMR before or after X-irradiation prevented changes in the total FA content in thymic tissue, returned the summary content of PUFA and MUFA to the control level and decreased the summary content of SFA on the 30th day after the treatments, and promoted the restoration of the thymus weight of X-irradiated mice to the 40th day of the observations. Changes in the content and composition of PUFA in the early period after treatments as well as at the restoration of the thymus weight under the combined action of EHF EMR and X-rays indicate to an active participation of FA in the acceleration of post-radiation recovery of the thymus by EHF EMR exposure.

Upcoversion performance improvement of NaYF4:Yb, Er by Sn codoping: Enhanced emission intensity and reduced decay time

International Nuclear Information System (INIS)

Yu, Han; Cao, Wenbing; Huang, Qingming; Ma, En; Zhang, Xinqi; Yu, Jianchang

2013-01-01

In this manuscript we report a phenomenon that upconversion emission intensity of Er 3+ was enhanced while decay time constant was decreased obviously by Sn codoping with Yb/Er into hexagonal NaYF 4 synchronously. X-ray powder diffiraction, field emission scanning electron microscope, transmission electron microscopy, X-ray photoelectron spectroscopy, electron spin-resonance spectroscopy and upconversion emission spectra were employed to explore the relation of crystal structure and properties. From these characterizations we found that symmetry of the rare earth ion local crystal field could be tuned by different Sn codoping concentration. For the variable valence property of Sn the local crystal field asymmetry and emission intensity of NaYF 4 :Yb, Er arrived to the maximum when 3 mol% Sn was codoped, while decay time was reduced. The study of this changing tends of upconversion emission intensity and decay time constant may be helpful for design and fabrication of high performance upconversion materials. - Graphical abstract: Variable-valenced Sn is introduced with Yb/Er into NaFY 4 to tune structure and local crystal field. Upconversion emission intensity of Er 3+ was enhanced while decay time constant was decreased. Display Omitted - Highlights: • NaYF 4 : Yb, Er was codoped with different concentration Sn. • Upconversion emission intensity was enhanced while decay time constant was decreased. • Introduction of variable-valenced Sn is effective to tune structure and crystal field of NaFY 4

A comparison of theoretical and solar-flare intensity ratios for the Fe XIX X-ray lines

International Nuclear Information System (INIS)

Bhatia, A.K.; Mason, H.E.; Fawcett, B.C.; Phillips, K.J.H.

1989-04-01

Atomic data consisting of energy levels, g f-values and wavelengths are presented for the Fe XIX 2s 2 2p 4 -2s 2 2p 3 3s, 2s 2 2p 3 3d arrays that give rise to lines in solar flare and active-region X-ray spectra. Collision strengths and theoretical intensity ratios are given for the 2s 2 2p 4 -2s 2 2p 3 3d lines, which occur in the 13.2-14.3 A range. Solar spectra in this range include a large number of other intense lines, notably those due to He-like Ne (Ne IX). Although the Ne IX lines are potentially the most useful indicators of electron density in solar X-ray spectra, blending with the Fe XIX lines has been a major problem for previous analyses. Comparison of observed spectra with those calculated from the Fe XIX atomic data presented here and Ne IX lines from other work indicates that there is generally good agreement. We use the calculated Fe XIX and Ne IX line spectra and several observed spectra during a flare previously analysed to estimate electron density from Ne IX line ratios, thus for the first time properly taking into account blends with Fe XIX lines. (author)

Contribution of inner shell Compton ionization to the X-ray fluorescence line intensity

Science.gov (United States)

Fernández, Jorge E.; Scot, Viviana; Di Giulio, Eugenio

2016-10-01

The Compton effect is a potential ionization mechanism of atoms. It produces vacancies in inner shells that are filled with the same mechanism of atomic relaxation as the one following photo-absorption. This contribution to X-ray fluorescence emission is frequently neglected because the total Compton cross-section is apparently much lower than the photoelectric one at useful X-ray energies. However, a more careful analysis suggests that is necessary to consider single shell cross sections (instead of total cross sections) as a function of energy. In this article these Compton cross sections are computed for the shells K, L1-L3 and M1-M5 in the framework of the impulse approximation. By comparing the Compton and the photoelectric cross-section for each shell it is then possible to determine the extent of the Compton correction to the intensity of the corresponding characteristic lines. It is shown that for the K shell the correction becomes relevant for excitation energies which are too high to be influent in X-ray spectrometry. In contrast, for L and M shells the Compton contribution is relevant for medium-Z elements and medium energies. To illustrate the different grades of relevance of the correction, for each ionized shell, the energies for which the Compton contribution reaches the extent levels of 1, 5, 10, 20, 50 and 100% of the photoelectric one are determined for all the elements with Z = 11-92. For practical applications it is provided a simple formula and fitting coefficients to compute average correction levels for the shells considered.

Modelling properties of hard x-rays generated by the interaction between relativistic electrons and very intense laser beams

International Nuclear Information System (INIS)

Popa, Alexandru

2009-01-01

In a previous paper we presented a calculation model for high harmonic generation by relativistic Thomson scattering of the electromagnetic radiation by free electrons. In this paper we present a similar model for the calculation of the energies of hard x-rays (20- 200 keV) resulted from the interaction between relativistic electrons (20-100 MeV) and very intense laser beams. Starting from the relativistic equations of motion of an electron in the electromagnetic field we show that the Lienard-Wiechert equation leads to electromagnetic waves whose frequencies are in the domain of hard x-rays. When the relativistic parameter of the laser beam is greater than unity, the model predicts the existence of harmonics of the above frequencies. Our theoretical values are in good agreement with experimental values of the x-ray energies from the literature and predict accurately their angular distribution.

Fatigue life assessment for pipeline welds by x-ray diffraction technique

International Nuclear Information System (INIS)

Lee, Sang Guk; Yoo, Keun Bong

2006-01-01

The objective of this study is to estimate the feasibility of X-ray diffraction method application for fatigue life assessment of the high-temperature pipeline steel such as main steam pipe, re-heater pipe and header etc. in power plant. In this study, X-ray diffraction tests using various types of specimen simulated low cycle fatigue damage were performed in order to analyze fatigue properties when fatigue damage conditions become various stages such as 1/4, l/2 and 3/4 of fatigue life, respectively. As a result off-ray diffraction tests for specimens simulated fatigue damages, we conformed that the variation of the full width at half maximum intensity decreased in proportion to the increase of fatigue life ratio. And also, He ratio of the full width at half maximum intensity due to fatigue damage has linear relationship with fatigue life ratio algebraically. From this relationship, it was suggested that direct expectation of the life consumption rate was feasible.

Upcoversion performance improvement of NaYF{sub 4}:Yb, Er by Sn codoping: Enhanced emission intensity and reduced decay time

Energy Technology Data Exchange (ETDEWEB)

Yu, Han, E-mail: fjfzyh@fzu.edu.cn [College of Materials Science and Engineering, Fuzhou University, Fuzhou, Fujian 350108 (China); Cao, Wenbing [College of Materials Science and Engineering, Fuzhou University, Fuzhou, Fujian 350108 (China); Huang, Qingming [Instrumentation Analysis and Research Center, Fuzhou University, Fuzhou, Fujian 350002 (China); Ma, En [Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China); Zhang, Xinqi [Instrumentation Analysis and Research Center, Fuzhou University, Fuzhou, Fujian 350002 (China); Yu, Jianchang [College of Materials Science and Engineering, Fuzhou University, Fuzhou, Fujian 350108 (China)

2013-11-15

In this manuscript we report a phenomenon that upconversion emission intensity of Er{sup 3+} was enhanced while decay time constant was decreased obviously by Sn codoping with Yb/Er into hexagonal NaYF{sub 4} synchronously. X-ray powder diffiraction, field emission scanning electron microscope, transmission electron microscopy, X-ray photoelectron spectroscopy, electron spin-resonance spectroscopy and upconversion emission spectra were employed to explore the relation of crystal structure and properties. From these characterizations we found that symmetry of the rare earth ion local crystal field could be tuned by different Sn codoping concentration. For the variable valence property of Sn the local crystal field asymmetry and emission intensity of NaYF{sub 4}:Yb, Er arrived to the maximum when 3 mol% Sn was codoped, while decay time was reduced. The study of this changing tends of upconversion emission intensity and decay time constant may be helpful for design and fabrication of high performance upconversion materials. - Graphical abstract: Variable-valenced Sn is introduced with Yb/Er into NaFY{sub 4} to tune structure and local crystal field. Upconversion emission intensity of Er{sup 3+} was enhanced while decay time constant was decreased. Display Omitted - Highlights: • NaYF{sub 4}: Yb, Er was codoped with different concentration Sn. • Upconversion emission intensity was enhanced while decay time constant was decreased. • Introduction of variable-valenced Sn is effective to tune structure and crystal field of NaFY{sub 4}.

Solar cycle dependence of the radial gradient of cosmic ray intensity

International Nuclear Information System (INIS)

Allen, J.A.V.

1988-01-01

Observation of the interplanetary intensity of cosmic rays (E/sub p/>80 MeV) by Pioneers 10 and 11 now spans a sixteen-year time period 1972--1988 and heliocentric radial distances, r/sub 10/ and r/sub 11/, out to 43.7 AU for Pioneer 10 and 25.8 AU for Pioneer 11. Solar modulation continues to be present at the current distances of both spacecraft. The radial gradient of intensity is measured continuously over the slowly varying, outward moving radial segment Δr = r/sub 10/--r/sub 11/. The 50-day mean values of the gradient G vary systematically and cyclically in phase with solar activity as measured by sunspot number, with a maximum value of about 2.1 percent (AU)/sup -1/ at sunspot maximum and a miminum value of about 1.2 percent (AU)/sup -1/ at sunspot minimum. Thus, the apparent scale size of the heliospheric modulation region as measured by 1/G is about 48 AU at solar max and about 83 AU at solar min: a result that is the inverse of the conjectural inference of Randall and Van Allen [1986] using most of the same body of data but a different analytical point of view. There is persuasive evidence that G is independent of radial distance over the range 2.5 to 34 AU in the mid-point of the segment Δr. No dependence of G on heliographic latitude is evident, but this result does not lend itself to a quantitative statement. copyright American Geophysical Union 1988

Measurement of secondary gamma-ray skyshine and groundshine from intense 14 MeV neutron source facility

Energy Technology Data Exchange (ETDEWEB)

Yoshida, Shigeo; Morotomi, Ryutaro; Kondo, Tetsuo; Murata, Isao; Takahashi, Akito [Osaka Univ., Suita (Japan). Dept. of Nuclear Engineering

2000-03-01

Secondary gamma-ray skyshine and groundshine, including the direct contribution from the facility building, have been measured with an Hp-Ge detector and an NaI(Tl) detector at the Intense 14 MeV Neutron Source Facility OKTAVIAN of Osaka University, Japan. The mechanism of secondary gamma-rays propagation were analyzed with the measured spectrum with the Hp-Ge detector. The contribution of the skyshine was shown to be a continuum spectrum that was composed of mainly Compton scattered high energy secondary gamma-rays generated in the facility building created by (n, {gamma}) reaction. The contribution of the groundshine considerably contained secondary gamma-rays generated by {sup nat}Si (n, {gamma}) reaction in soil, including the albedo contribution from the ground. And the total contribution contained capture gamma-rays from iron (Fe) and other nuclides. The measurements with the NaI(Tl) detector as well as the Hp-Ge detector were carried out to investigate the dependence of gamma-ray dose as a function of distance from the neutron source up to hundreds meters. Consequently, it was found that the dependence could be fitted with the function of const.{center_dot}exp(-r/{lambda})/r{sup n}, where n values were around 2 except for the skyshine (n {approx} 1). It was thus indicated that the contribution of the skyshine could be propagated farther downfield than the direct contribution from the facility. The measured ratios of the three contributions (skyshine, groundshine, and direct contributions) and the distance dependence in each path were shown to be in good agreement with calculated results by the Monte Carlo transport code MCNP-4A. And the total contributions for the two detectors of NaI(Tl) and Hp-Ge agree excellently with each other. (author)

Intensity profiles behind a five-stage neutron interferometer

International Nuclear Information System (INIS)

Kischko, U.

1983-01-01

By means of the quantitative photography intensity profiles behind a five-stage ideal-crystal neutron interferometer at the thermal channel H25 of the high-flux reactor at the institute Laue-Langevin in Grenoble/France were dermined and compared with theoretical profiles. Contravily to X-rays by neutrons the hole Borrmann range is excited. This leads in the interference picture to superposition of several wave field components. It was shown that the spherical wave theory, as it was developed by W. Bauspiess, U. Bonse, and W. Graeff for the absorption-free neutron interferometer, describes well quantitatively the experimental intensity profiles. Expecially for the t-2t-t geometry the theoretically predicted focusing was confirmed. For the H-beam the intensity profile is symmetric and spatially limited; the O-beam is asymetric with intensities decreasing slowly up to the boundary. Geometrical differences within single stages lead to unique changes in the intensity profile. The pigtail pattern leading in the past to some puzzle guessing could be explained by the influence of geometrical defocusings on the phase shift. Important conclusions for the geometrical tolerances, which have to be regarded in the construction of neutron interferometers, could be obtained. (orig.) [de

X-ray examination apparatus

NARCIS (Netherlands)

2000-01-01

The invention relates to an X-ray apparatus which includes an adjustable X-ray filter. In order to adjust an intensity profile of the X-ray beam, an X-ray absorbing liquid is transported to filter elements of the X-ray filter. Such transport is susceptible to gravitational forces which lead to an

Simulations of bremsstrahlung emission in ultra-intense laser interactions with foil targets

Science.gov (United States)

Vyskočil, Jiří; Klimo, Ondřej; Weber, Stefan

2018-05-01

Bremsstrahlung emission from interactions of short ultra-intense laser pulses with solid foils is studied using particle-in-cell (PIC) simulations. A module for simulating bremsstrahlung has been implemented in the PIC loop to self-consistently account for the dynamics of the laser–plasma interaction, plasma expansion, and the emission of gamma ray photons. This module made it possible to study emission from thin targets, where refluxing of hot electrons plays an important role. It is shown that the angular distribution of the emitted photons exhibits a four-directional structure with the angle of emission decreasing with the increase of the width of the target. Additionally, a collimated forward flash consisting of high energy photons has been identified in thin targets. The conversion efficiency of the energy of the laser pulse to the energy of the gamma rays rises with both the driving pulse intensity, and the thickness of the target. The amount of gamma rays also increases with the atomic number of the target material, despite a lower absorption of the driving laser pulse. The angular spectrum of the emitted gamma rays is directly related to the increase of hot electron divergence during their refluxing and its measurement can be used in experiments to study this process.

Thirty Minutes of Running Exercise Decreases T2 Signal Intensity but Not Thickness of the Knee Joint Cartilage: A 3.0-T Magnetic Resonance Imaging Study.

Science.gov (United States)

Karanfil, Yiğitcan; Babayeva, Naila; Dönmez, Gürhan; Diren, H Barış; Eryılmaz, Muzaffer; Doral, Mahmut Nedim; Korkusuz, Feza

2018-04-01

Objective Recent studies showed a potential of magnetic resonance imaging (MRI), which can be used as an additional tool for diagnosing cartilage degeneration in the early stage. We designed a cross-sectional study in order to evaluate knee joint cartilage adaptation to running, using 3.0-T MRI equipped with the 3-dimensional turbo spin echo (VISTA = Volume ISotropic Turbo spin echo Acquisition) software. By this thickness (mm) and signal intensity (mean pixel value) can be quantified, which could be closely related to the fluid content of the knee joint cartilage, before and after running. Methods A total of 22 males, aged 18 to 35 years, dominant (right) and nondominant (left) knees were assessed before and after 30 minutes of running. Cartilage thickness and signal intensity of surfaces of the patella, medial and lateral femoral and tibial condyles were measured. Results Cartilage thickness of the lateral condyle decreased at the dominant knee, while it increased at the medial tibial plateau. Signal intensity decreased at all locations, except the lateral patella in both knees. The most obvious decrease in signal intensity (10.6%) was at the medial tibial plateau from 949.8 to 849.0 of the dominant knee. Conclusion There was an increase in thickness measurements and decrease in signal intensity in medial tibial plateau of the dominant knee after 30 minutes of running. This outcome could be related to fluid outflow from the tissue. Greater reductions in the medial tibial plateau cartilage indicate greater load sharing by these areas of the joint during a 30-minute running.

Prompt gamma-ray analysis of steel slag in concrete

International Nuclear Information System (INIS)

Naqvi, Akhtar Abbas; Garwan, Muhammad Ahmad; Nagadi, Mahmoud Mohammad; Rehman, Khateeb-ur; Raashid, Mohammad; Masalehuddin Mohiuddin, Mohammad; Al-Amoudi, Omar Saeed Baghabra

2009-01-01

Blast furnace slag (BFS) is added to Portland cement concrete to increase its durability, particularly its corrosion resistance. Monitoring the concentration of BFS in concrete for quality control purposes is desired. In this study, the concentration of BFS in concrete was measured by utilizing an accelerator-based prompt gamma-ray neutron activation analysis (PGNAA) setup. The optimum size of the BFS cement concrete specimen that produces the maximum intensity of gamma rays at the detector location was calculated through Monte Carlo simulations. The simulation results were experimentally validated through the gamma-ray yield measurement from BFS cement concrete specimens having different radii. The concentration of BFS in the cement concrete specimens was assessed through calcium and silicon gamma-ray yield measurement from cement concrete specimens containing 5 to 80 wt% BFS. The yield of calcium gamma rays decreases with increasing BFS concentration in concrete while the yield of silicon gamma rays increases with increasing BFS concentration in concrete. The calcium-to-silicon gamma-ray yield ratio has an inverse relation with BFS concentration in concrete. (author)

Modelling cosmic ray intensities along the Ulysses trajectory

Directory of Open Access Journals (Sweden)

D. C. Ndiitwani

2005-03-01

Full Text Available Time dependent cosmic ray modulation in the inner heliosphere is studied by comparing results from a 2-D, time-dependent cosmic ray transport model with Ulysses observations. A compound approach, which combines the effects of the global changes in the heliospheric magnetic field magnitude with drifts to establish a realistic time-dependence, in the diffusion and drift coefficients, are used. We show that this model results in realistic cosmic ray modulation from the Ulysses launch (1990 until recently (2004 when compared to 2.5-GV electron and proton and 1.2-GV electron and Helium observations from this spacecraft. This approach is also applied to compute radial gradients present in 2.5-GV cosmic ray electron and protons in the inner heliosphere. The observed latitude dependence for both positive and negative charged particles during both the fast latitude scan periods, corresponding to different solar activity conditions, could also be realistically computed. For this an additional reduction in particle drifts (compared to diffusion toward solar maximum is needed. This results in a realistic charge-sign dependent modulation at solar maximum and the model is also applied to predict charge-sign dependent modulation up to the next expected solar minimum.

X-ray or UV-ray imaging sensor utilizing optically stimulated luminescence phenomenon in Eu-doped KCl phosphors

International Nuclear Information System (INIS)

Nanto, Hidehito; Murayama, Kazuhiko; Hirai, Yoshiaki; Taniguchi, Shin-ichi; Makamura, Shouichi; Takeuchi, Nozomu.

1993-01-01

An intense OSL with a peak at about 420 [nm] has been observed by stimulating an X-ray or UV-ray irradiated KCl: Eu crystal with F-band light whose wavelength is about 560 [um]. A possible excitation and emission mechanisms for the 420 [um] OSL peak X-ray or UV-ray irradiated sample is proposed. It is found that the OSL intensity is proportional to the X-ray absorbed dose or UV-ray irradiation dose. It is also found that X-ray or UV-ray irradiated KCl; Eu exhibited excellent fading characteristics. These results strongly suggest that the KCl: Eu is one of the most attractive candidates for two-dimensional X-ray or UV-ray imaging sensor utilizing the OSL phenomenon. (J.P.N.)

Temperature Effect in Secondary Cosmic Rays (MUONS) Observed at the Ground: Analysis of the Global MUON Detector Network Data

Science.gov (United States)

de Mendonça, R. R. S.; Braga, C. R.; Echer, E.; Dal Lago, A.; Munakata, K.; Kuwabara, T.; Kozai, M.; Kato, C.; Rockenbach, M.; Schuch, N. J.; Jassar, H. K. Al; Sharma, M. M.; Tokumaru, M.; Duldig, M. L.; Humble, J. E.; Evenson, P.; Sabbah, I.

2016-10-01

The analysis of cosmic ray intensity variation seen by muon detectors at Earth's surface can help us to understand astrophysical, solar, interplanetary and geomagnetic phenomena. However, before comparing cosmic ray intensity variations with extraterrestrial phenomena, it is necessary to take into account atmospheric effects such as the temperature effect. In this work, we analyzed this effect on the Global Muon Detector Network (GMDN), which is composed of four ground-based detectors, two in the northern hemisphere and two in the southern hemisphere. In general, we found a higher temperature influence on detectors located in the northern hemisphere. Besides that, we noticed that the seasonal temperature variation observed at the ground and at the altitude of maximum muon production are in antiphase for all GMDN locations (low-latitude regions). In this way, contrary to what is expected in high-latitude regions, the ground muon intensity decrease occurring during summertime would be related to both parts of the temperature effect (the negative and the positive). We analyzed several methods to describe the temperature effect on cosmic ray intensity. We found that the mass weighted method is the one that best reproduces the seasonal cosmic ray variation observed by the GMDN detectors and allows the highest correlation with long-term variation of the cosmic ray intensity seen by neutron monitors.

Effect of gamma rays on crystalline materials during irradiation in a reactor

International Nuclear Information System (INIS)

Nikolaenko, V.A.; Karpukhin, V.I.; Gordeev, V.G.

1995-01-01

The article presents and discusses the results of experiments to determine the effect of gamma rays on the change in the properties of diamond, graphite, and structural steel. The materials were irradiated in a VVER type reactor. For diamonds, the effect on the annealing of defects was investigated. As gamma ray intensity increased, the crystal lattice expansion and defect concentration increased. Graphite lattice expansion and the mechanical properties of structural steel were also examined. Graphite lattice expansion increased with increased neutron flux and decreased irradiation temperature. Changes in the impact toughness of structural steel correlated precisely to the gamma ray flux in the experiments. 6 refs., 3 figs

X-ray diffraction patterns and diffracted intensity of Kα spectral lines of He-like ions

Science.gov (United States)

Goyal, Arun; Khatri, Indu; Singh, A. K.; Sharma, Rinku; Mohan, Man

2017-09-01

In the present paper, we have calculated fine-structure energy levels related to the configurations 1s2s, 1s2p, 1s3s and 1s3p by employing GRASP2K code. We have also computed radiative data for transitions from 1s2p 1 P1o, 1s2p 3 P2o, 1s2p 3 P1o and 1s2s 3S1 to the ground state 1s2. We have made comparisons of our presented energy levels and transition wavelengths with available results compiled by NIST and good agreement is achieved. We have also provided X-ray diffraction (XRD) patterns of Kα spectral lines, namely w, x, y and z of Cu XXVIII, Kr XXXV and Mo with diffraction angle and maximum diffracted intensity which is not published elsewhere in the literature. We believe that our presented results may be beneficial in determination of the order parameter, X-ray crystallography, solid-state drug analysis, forensic science, geological and medical applications.

Relationship between x-ray illumination field size and flat field intensity and its impacts on x-ray imaging

International Nuclear Information System (INIS)

Dong Xue; Niu Tianye; Jia Xun; Zhu Lei

2012-01-01

Purpose: X-ray cone-beam CT (CBCT) is being increasingly used for various clinical applications, while its performance is still hindered by image artifacts. This work investigates a new source of reconstruction error, which is often overlooked in the current CBCT imaging. The authors find that the x-ray flat field intensity (I 0 ) varies significantly as the illumination volume size changes at different collimator settings. A wrong I 0 value leads to inaccurate CT numbers of reconstructed images as well as wrong scatter measurements in the CBCT research. Methods: The authors argue that the finite size of x-ray focal spot together with the detector glare effect cause the I 0 variation at different illumination sizes. Although the focal spot of commercial x-ray tubes typically has a nominal size of less than 1 mm, the off-focal-spot radiation covers an area of several millimeters on the tungsten target. Due to the large magnification factor from the field collimator to the detector, the penumbra effects of the collimator blades result in different I 0 values for different illumination field sizes. Detector glare further increases the variation, since one pencil beam of incident x-ray is scattered into an area of several centimeters on the detector. In this paper, the authors study these two effects by measuring the focal spot distribution with a pinhole assembly and the detector point spread function (PSF) with an edge-spread function method. The authors then derive a formula to estimate the I 0 value for different illumination field sizes, using the measured focal spot distribution and the detector PSF. Phantom studies are carried out to investigate the accuracy of scatter measurements and CT images with and without considering the I 0 variation effects. Results: On our tabletop system with a Varian Paxscan 4030CB flat-panel detector and a Varian RAD-94 x-ray tube as used on a clinical CBCT system, the focal spot distribution has a measured full

Airplane radiation dose decrease during a strong Forbush decrease

Czech Academy of Sciences Publication Activity Database

Spurný, František; Kudela, K.; Dachev, T.

2004-01-01

Roč. 2, S05001 (2004), s. 1-4 ISSN 1542-7390 Grant - others:EC project(XE) FIGM-CT2000-00068 Institutional research plan: CEZ:AV0Z1048901 Keywords : airplane dose * Forbush decrease * cosmic rays Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders

The decreasing effect of exogenous SOD on damage of mice irradiated with 5 Gy 60Co-γ rays

International Nuclear Information System (INIS)

Liu Fenju; Jiang Jiagui; Yi Jian

1999-01-01

The author presents a report on the activity of Superoxide Dismutase (SOD) and the content of LPO measured in tissue of Liver, heart and brain of mice irradiated by 60 Co-γ rays 5 Gy 1, 3, 5 and 8 days after irradiation respectively. After radiation exogenous SOD was immediately i.p. injected into mice. The variation of LPO content in the above mentioned three kinds of tissue has been observed. The result of the measurement shows that after radiation at a dose of 5 Gy 60 Co-γ rays, the LPO content and SOD activity of mice organs varied with radiation time. The LPO content varied earliest in liver, while the variation of LPO content in heart and cerebrum took place 8 days after radiation, meanwhile the activity of SOD in the tissues significantly decreased in comparison with that the control group (P<0.01). After injection with SOD, the LPO content and SOD activity of the organs irradiated for different time significantly decreased and increased in comparison with that in the control group. This shows that the enzyme of SOD is of significant anti-radiation effect

Monte Carlo simulation of photon scattering in x-ray absorption imaging of high-intensity discharge lamps

Energy Technology Data Exchange (ETDEWEB)

Curry, J J, E-mail: jjcurry@nist.go [National Institute of Standards and Technology, Gaithersburg, MD 20899-8422 (United States)

2010-06-16

Coherent and incoherent scattering of x-rays during x-ray absorption imaging of high-intensity discharge lamps have been studied with Monte Carlo simulations developed specifically for this purpose. The Monte Carlo code is described and some initial results are discussed. Coherent scattering, because of its angular concentration in the forward direction, is found to be the most significant scattering mechanism. Incoherent scattering, although comparably strong, is not as significant because it results primarily in photons being scattered in the rearward direction and therefore out of the detector. Coherent scattering interferes with the detected absorption signal because the path of a scattered photon through the object to be imaged is unknown. Although scattering is usually a small effect, it can be significant in regions of high contrast. At the discharge/wall interface, as many as 50% of the detected photons are scattered photons. The effect of scattering on analysis of Hg distributions has not yet been quantified.

Cosmic ray modulation

International Nuclear Information System (INIS)

Ueno, Hirosachi

1974-01-01

It is important to know the physical state of solar plasma region by the observation of intensity variation of cosmic ray which passed through the solar plasma region, because earth magnetosphere is formed by the interaction between geomagnetic field and solar plasma flow. The observation of cosmic ray intensity is useful to know the average condition of the space of 0.1--3 A.U., and gives the structure of the magnetic field in solar wind affecting the earth magnetosphere. The observation of neutron component in cosmic ray has been carried out at Norikura, Tokyo, Fukushima and Morioka. The lower limit of the energy of incident cosmic ray which can be observed at each station is different, and the fine structure of the variation can be known by comparison. The intensity of meson component in cosmic ray has been measured in underground, and the state of solar plasma region 2--3 A.U. from the earth can be known. The underground measurement has been made at Takeyama and Matsumoto, and a new station at Sakashita is proposed. The measurement at Sakashita will be made by proportional counters at the depth of 100m (water equivalent). Arrangement of detectors is shown. (Kato, T.)

X-ray sensitive strains of CHO cells show decreased frequency of stable transfection

International Nuclear Information System (INIS)

Jeggo, P.; Smith, J.

1987-01-01

Six X-ray sensitive (xrs) strains of the Chinese hamster ovary cell line have previously been isolated and shown to have a defect in double strand break rejoining. In this study, these strains have been investigated for their ability to take up and integrate foreign DNA. All the xrs strains investigated so far have shown a decreased frequency of stable transfectants compared to their parent line, in experiments using the plasmid pSV2gpt, which contains the selectable bacterial gene, guanine phosphoribosyl transferase. This decreased frequency is observed over a wide range of DNA concentrations (0.1 to 20 μg DNA) but is more pronounced at higher DNA concentrations. In contrast, these xrs strains show the same level of transfection proficiency as the wild type parent using a transient transfection system with a plasmid containing the bacterial CAT (chloramphenicol acetyl transferase) gene. Since the level of CAT activity does not depend on integration of foreign DNA, this suggests that the xrs strains are able to take up the same amount of DNA as the parent strains, but have a defect in the integration of foreign DNA. Since this integration of foreign DNA probably occurs by non-homologous recombination, this may indicate a role of the xrs gene product in this process

Effects of high-intensity pulse irradiation with linear polarized near-infrared rays and stretching on muscle tone in patients with cerebrovascular disease: a randomized controlled trial.

Science.gov (United States)

Takeuchi, Nobuyuki; Takezako, Nobuhiro; Shimonishi, Yuko; Usuda, Shigeru

2017-08-01

[Purpose] The purpose of this study was to clarify the influence of high-intensity pulse irradiation with linear polarized near-infrared rays (HI-LPNR) and stretching on hypertonia in cerebrovascular disease patients. [Subjects and Methods] The subjects were 40 cerebrovascular disease patients with hypertonia of the ankle joint plantar flexor muscle. The subjects were randomly allocated to groups undergoing treatment with HI-LPNR irradiation (HI-LPNR group), stretching (stretching group), HI-LPNR irradiation followed by stretching (combination group), and control group (10 subjects each). In all groups, the passive range of motion of ankle dorsiflexion and passive resistive joint torque of ankle dorsiflexion were measured before and after the specified intervention. [Results] The changes in passive range of motion, significant increase in the stretching and combination groups compared with that in the control group. The changes in passive resistive joint torque, significant decrease in HI-LPNR, stretching, and combination groups compared with that in the control group. [Conclusion] HI-LPNR irradiation and stretching has effect of decrease muscle tone. However, combination of HI-LPNR irradiation and stretching has no multiplier effect.

Characteristics of X-ray photons in tilted incident laser-produced plasma

International Nuclear Information System (INIS)

Wang Ruirong; Chen Weimin; Xie Dongzhu

2008-01-01

Characteristics of X-ray and spout direction of heat plasma flow were studied on Shenguang-II laser facility. Using of pinhole X-ray camera, X-ray photons from the plasma of aluminum (Al) irradiated by 1.053 μm laser, was measured and analysed. It is observed that the spatial distribution of X-ray photons in Al plasma for tilted irradiation is symmetic at the center of the target. The spout direction of heat plasma flow is inferred by the distribution contour of X-ray photons. the experimental results show that the spout direction of heat plasma flow is normal to target plane and the output intensity of X-ray photons does not increase significantly for tilted laser incidence. Uniformity of laser energy deposition is improved by superposing tilted incident and laser perpendicularly incident laser. At the same time, it is found that the conversion efficiency from the tilted incident laser energy to X-ray photons of laser-produced plasma is decreased. (authors)

Exposure assessment of neonates in israel to x-ray radiation during hospitalization at neonatal intensive care unit

International Nuclear Information System (INIS)

Datz, H.

2005-03-01

Nowadays nearly 10% of all births in western countries are premature. In the last decade, there has been an increase of 45% in the number of neonates that were born in Israel. At the same time, the survival of neonates, especially those with very low birth weight, VLBW, (less than 1,500 gr), has increased dramatically. Diagnostic radiology plays an important role in the assessment and treatment of neonates requiring intensive care. During their prolonged and complex hospitalization, these infants are exposed to multiple radiographic examinations involving X-ray radiation. The extent of the examinations that the infant undergoes depends on its birth weight, gestational age and its medical problems, where most of the treatment effort is focused especially on VLBW neonates. Most of the diagnostic X-ray examinations taken during the hospitalization of neonates in the neonatal intensive care unit (NICU) consist of imaging of the respiratory and gastrointestinal systems, namely, the chest and abdomen. The imaging process is done using mobile X-ray units located at the NICUs. Due to their long hospitalization periods and complex medical condition, all neonates, and neonates with VLBW in particular, are exposed to a much higher level of diagnostic radiation, compared to normal newborns. The goal of this research was to assess the extent of the exposure of neonates in Israel to X-ray radiation during their hospitalization at the neonatal intensive care unit. Five NICUs, located at different geographical zones in Israel and treating 20% of all newborns in Israel every year, participated in this research. The research was conducted in three phases: Phase I: Collection of information on radiographic techniques and exposure parameters (e.g. kV, mAs, focus to skin distance (FSD), examination borders). 499 X-ray examinations (from 157 neonates) were evaluated for necessary and unnecessary exposure of the neonate's organs to X-ray radiation during these examinations. Phase II

X-ray spectroscopy and X-ray crystallography of metalloenzymes at XFELs

International Nuclear Information System (INIS)

Yano, Junko

2016-01-01

The ultra-bright femtosecond X-ray pulses provided by X-ray Free Electron Lasers (XFELs) open capabilities for studying the structure and dynamics of a wide variety of biological and inorganic systems beyond what is possible at synchrotron sources. Although the structure and chemistry at the catalytic sites have been studied intensively in both biological and inorganic systems, a full understanding of the atomic-scale chemistry requires new approaches beyond the steady state X-ray crystallography and X-ray spectroscopy at cryogenic temperatures. Following the dynamic changes in the geometric and electronic structure at ambient conditions, while overcoming X-ray damage to the redox active catalytic center, is key for deriving reaction mechanisms. Such studies become possible by using the intense and ultra-short femtosecond X-ray pulses from an XFEL, where sample is probed before it is damaged. We have developed methodology for simultaneously collecting crystallography data and X-ray emission spectra, using an energy dispersive spectrometer at ambient conditions. In addition, we have developed a way to collect metal L-edge data of dilute samples using soft X-rays at XFELs. The advantages and challenges of these methods will be described in this review. (author)

Multilayered samples reconstructed by measuring Kα/Kβ or Lα/Lβ X-ray intensity ratios by EDXRF

Science.gov (United States)

Cesareo, Roberto; de Assis, Joaquim T.; Roldán, Clodoaldo; Bustamante, Angel D.; Brunetti, Antonio; Schiavon, Nick

2013-10-01

In this paper a general method based on energy-dispersive X-ray fluorescence (EDXRF) analysis has been tested to assess its possible use as a tool to reconstruct the structure and determine the thickness of two and/or multi-layered materials. The method utilizes the X-ray intensity ratios of Kα/Kβ or Lα/Lβ peaks (or the ratio of these peaks) for selected elements present in multi-layered objects of various materials (Au alloys, gilded Cu, gilded Ag, gilded Pb, Ag-Au Tumbaga, stone surfaces with protective treatments, Zn or Nickel plating on metals). Results show that, in the case of multi-layered samples, a correct calculation of the peak ratio (Kα /Kβ and/or Lα/Lβ) of relevant elements from energy-dispersive X-ray fluorescence spectra, can provide important information in assessing the exact location of each layer and for calculating its thickness. The methodological approach shown may have important applications not only in materials science but also when dealing with the conservation and restoration of multi-layered cultural heritage objects where the use of a Non-Destructive techniques to determine slight chemical and thickness variations in the layered structure is often of paramount importance to achieve the best results.

Resonance γ-ray polarimetry

International Nuclear Information System (INIS)

Gonser, U.; Fischer, H.

1981-01-01

The topics are: Intensity and polarization of radiation in Moessbauer transitions, hyperfine interactions in 57 Fe, polarized γ-rays, polarimetry, γ-ray rotation polarimeters, Birefringence polarimetry. (WL)

Department of Cosmic Ray Physics; Overview

International Nuclear Information System (INIS)

Szabelski, J.

2003-01-01

Full text: Department of Cosmic Ray Physics in Lodz is involved in basic research in the area of high-energy physics and cosmic ray physics related to: - Experimental and phenomenological studies of Extensive Air Showers induced by cosmic ray particles. - Studies of ultra-high energy (above 10 19 eV) cosmic rays: determination of energy spectrum and mass composition of primary particles - Studies of asymptotic properties of hadronic interactions based on the analysis of cosmic ray propagation through the atmosphere. - Studies of mass composition of cosmic rays in the energy range 10 15 - 10 17 eV. - Registration of cosmic ray intensity variation correlated with solar activity. Theoretical and experimental studies of Extensive Air Shower properties are performed mostly basing on the results obtained by the Lodz Extensive Air Shower Array. We have noticed unexplainable delayed signals registered about 500-900 microseconds after the main EAS pulse. Neutron transport simulations were performed in collaboration with JINR in Dubna. We prepared hardware for further experimental study of this effect. Continuous registrations of 5 GeV muon flux with the underground muon telescope have been carried on over the year 2001. We have detected several changes of muon intensity correlated with Forbush decreases registered at lower energies. We have also started registrations of muon counting rate in the on-surface scintillation detectors. These measurements will be included to the analysis of the disturbed energy spectrum of primary cosmic rays and its dependence on interplanetary disturbances related to the solar activity. In construction and data interpretation of cosmic ray experiments the Lodz group collaborates with many foreign institutes and laboratories: Forschungszentrum in Karlsruhe (Germany), College de France, Institute for Nuclear Studies of the Russian Academy of Sciences, JINR in Dubna (Russia), Uppsala University (Sweden) and DESY (Germany). We have prepared a

Department of Cosmic Ray Physics: Overview

International Nuclear Information System (INIS)

Szabelski, J.

2002-01-01

Full text:The Department of Cosmic Ray Physics in Lodz is involved in basic research in the area of high-energy physics and cosmic ray physics related to: * Experimental and phenomenological studies of Extensive Air Showers induced by cosmic ray particles. * Studies of ultra-high energy (above 10 19 eV) cosmic rays: determination of energy spectrum and mass composition of primary particles * Studies of asymptotic properties of hadronic interactions based on the analysis of cosmic ray propagation through the atmosphere. * Studies of mass composition of cosmic rays in the energy range 10 15 -10 17 eV. * Registration of cosmic ray intensity variation correlated with solar activity. Theoretical and experimental studies of Extensive Air Shower properties are performed mostly based on the results obtained by the Lodz Extensive Air Shower Array. We have noticed unexplainable delayed signals registered about 500-900 microseconds after the main EAS pulse. We prepared hardware for further experimental study of this effect. Continuous registrations of 5 GeV muon flux with the underground muon telescope have been carried on during 2001. We detected several changes of muon intensity correlated with Forbush decreases registered at lower energies. We have also started registration of the muon counting rate in on-surface scintillation detectors. These measurements will be included to the analysis of the disturbed energy spectrum of primary cosmic rays and its dependence on interplanetary disturbances related to solar activity. In construction and data interpretation of cosmic ray experiments the Lodz group collaborates with many foreign institutes and laboratories: Forschungszentrum in Karlsruhe (Germany), College de France, Institute for Nuclear Studies of the Russian Academy of Sciences, Uppsala University (Sweden) and DESY (Germany). We have prepared a project of large air shower array for studies of cosmic rays up to 10 20 eV. Detectors would be placed on the roofs of high

THE TEMPERATURE EFFECT IN SECONDARY COSMIC RAYS (MUONS) OBSERVED AT THE GROUND: ANALYSIS OF THE GLOBAL MUON DETECTOR NETWORK DATA

Energy Technology Data Exchange (ETDEWEB)

De Mendonça, R. R. S.; Braga, C. R.; Echer, E.; Dal Lago, A.; Rockenbach, M.; Schuch, N. J. [Space Geophysics Division, National Institute for Space Research, São José dos Campos, SP, 12227-010 (Brazil); Munakata, K.; Kato, C. [Physics Department, Shinshu University, Matsumoto, Nagano, 390-8621 (Japan); Kuwabara, T. [Graduate School of Science, Chiba University, Chiba City, Chiba 263-8522 (Japan); Kozai, M. [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (ISAS/JAXA), Sagamihara, Kanagawa 252-5210 (Japan); Al Jassar, H. K.; Sharma, M. M. [Physics Department, Kuwait University, Kuwait City, 13060 (Kuwait); Tokumaru, M. [Solar Terrestrial Environment Laboratory, Nagoya University, Nagoya, Aichi, 464-8601 (Japan); Duldig, M. L.; Humble, J. E. [School of Physical Sciences, University of Tasmania, Hobart, Tasmania, 7001 (Australia); Evenson, P. [Bartol Research Institute, Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States); Sabbah, I. [Department of Natural Sciences, College of Health Sciences, Public Authority for Applied Education and Training, Kuwait City, 72853 (Kuwait)

2016-10-20

The analysis of cosmic ray intensity variation seen by muon detectors at Earth's surface can help us to understand astrophysical, solar, interplanetary and geomagnetic phenomena. However, before comparing cosmic ray intensity variations with extraterrestrial phenomena, it is necessary to take into account atmospheric effects such as the temperature effect. In this work, we analyzed this effect on the Global Muon Detector Network (GMDN), which is composed of four ground-based detectors, two in the northern hemisphere and two in the southern hemisphere. In general, we found a higher temperature influence on detectors located in the northern hemisphere. Besides that, we noticed that the seasonal temperature variation observed at the ground and at the altitude of maximum muon production are in antiphase for all GMDN locations (low-latitude regions). In this way, contrary to what is expected in high-latitude regions, the ground muon intensity decrease occurring during summertime would be related to both parts of the temperature effect (the negative and the positive). We analyzed several methods to describe the temperature effect on cosmic ray intensity. We found that the mass weighted method is the one that best reproduces the seasonal cosmic ray variation observed by the GMDN detectors and allows the highest correlation with long-term variation of the cosmic ray intensity seen by neutron monitors.

THE TEMPERATURE EFFECT IN SECONDARY COSMIC RAYS (MUONS) OBSERVED AT THE GROUND: ANALYSIS OF THE GLOBAL MUON DETECTOR NETWORK DATA

International Nuclear Information System (INIS)

De Mendonça, R. R. S.; Braga, C. R.; Echer, E.; Dal Lago, A.; Rockenbach, M.; Schuch, N. J.; Munakata, K.; Kato, C.; Kuwabara, T.; Kozai, M.; Al Jassar, H. K.; Sharma, M. M.; Tokumaru, M.; Duldig, M. L.; Humble, J. E.; Evenson, P.; Sabbah, I.

2016-01-01

The analysis of cosmic ray intensity variation seen by muon detectors at Earth's surface can help us to understand astrophysical, solar, interplanetary and geomagnetic phenomena. However, before comparing cosmic ray intensity variations with extraterrestrial phenomena, it is necessary to take into account atmospheric effects such as the temperature effect. In this work, we analyzed this effect on the Global Muon Detector Network (GMDN), which is composed of four ground-based detectors, two in the northern hemisphere and two in the southern hemisphere. In general, we found a higher temperature influence on detectors located in the northern hemisphere. Besides that, we noticed that the seasonal temperature variation observed at the ground and at the altitude of maximum muon production are in antiphase for all GMDN locations (low-latitude regions). In this way, contrary to what is expected in high-latitude regions, the ground muon intensity decrease occurring during summertime would be related to both parts of the temperature effect (the negative and the positive). We analyzed several methods to describe the temperature effect on cosmic ray intensity. We found that the mass weighted method is the one that best reproduces the seasonal cosmic ray variation observed by the GMDN detectors and allows the highest correlation with long-term variation of the cosmic ray intensity seen by neutron monitors.

Compton backscattered collmated X-ray source

Science.gov (United States)

Ruth, Ronald D.; Huang, Zhirong

2000-01-01

A high-intensity, inexpensive and collimated x-ray source for applications such as x-ray lithography is disclosed. An intense pulse from a high power laser, stored in a high-finesse resonator, repetitively collides nearly head-on with and Compton backscatters off a bunched electron beam, having relatively low energy and circulating in a compact storage ring. Both the laser and the electron beams are tightly focused and matched at the interaction region inside the optical resonator. The laser-electron interaction not only gives rise to x-rays at the desired wavelength, but also cools and stabilizes the electrons against intrabeam scattering and Coulomb repulsion with each other in the storage ring. This cooling provides a compact, intense bunch of electrons suitable for many applications. In particular, a sufficient amount of x-rays can be generated by this device to make it an excellent and flexible Compton backscattered x-ray (CBX) source for high throughput x-ray lithography and many other applications.

Compton backscattered collimated x-ray source

Science.gov (United States)

Ruth, R.D.; Huang, Z.

1998-10-20

A high-intensity, inexpensive and collimated x-ray source is disclosed for applications such as x-ray lithography is disclosed. An intense pulse from a high power laser, stored in a high-finesse resonator, repetitively collides nearly head-on with and Compton backscatters off a bunched electron beam, having relatively low energy and circulating in a compact storage ring. Both the laser and the electron beams are tightly focused and matched at the interaction region inside the optical resonator. The laser-electron interaction not only gives rise to x-rays at the desired wavelength, but also cools and stabilizes the electrons against intrabeam scattering and Coulomb repulsion with each other in the storage ring. This cooling provides a compact, intense bunch of electrons suitable for many applications. In particular, a sufficient amount of x-rays can be generated by this device to make it an excellent and flexible Compton backscattered x-ray (CBX) source for high throughput x-ray lithography and many other applications. 4 figs.

Production of hollow atoms by high brightness x-ray sources and its applications

International Nuclear Information System (INIS)

Moribayashi, Kengo

2004-01-01

We study x-ray emissions from the (multi-)inner-shell states and hollow atoms of Si ions excited by high intensity x-ray sources. It is found that the x-ray number from multi-inner-shell excited states (1s 2 2s 2 2p k 3s 2 3p 2 , k=1-4) and hollow atoms (1s 2 2s 2 3p 2 ) is affected greatly by the high intensity short-pulse x-rays and little by weak intensity post-long pulse x-rays. The ratio of the x-ray intensities from hollow atoms to those from the multi-inner-shell excited states becomes almost independent of the pulses and dependent on the intensities of x-ray sources. This ratio may be used for the measurement of intensities of high intensity short pulse x-ray sources. (author)

Decreased mortality in patients hospitalized due to respiratory diseases after installation of an intensive care unit in a secondary hospital in the interior of Brazil.

Science.gov (United States)

Diogo, Luciano Passamani; Bahlis, Laura Fuchs; Wajner, André; Waldemar, Fernando Starosta

2015-01-01

To evaluate the association between the in-hospital mortality of patients hospitalized due to respiratory diseases and the availability of intensive care units. This retrospective cohort study evaluated a database from a hospital medicine service involving patients hospitalized due to respiratory non-terminal diseases. Data on clinical characteristics and risk factors associated with mortality, such as Charlson score and length of hospital stay, were collected. The following analyses were performed: univariate analysis with simple stratification using the Mantel Haenszel test, chi squared test, Student's t test, Mann-Whitney test, and logistic regression. Three hundred thirteen patients were selected, including 98 (31.3%) before installation of the intensive care unit and 215 (68.7%) after installation of the intensive care unit. No significant differences in the clinical and anthropometric characteristics or risk factors were observed between the groups. The mortality rate was 18/95 (18.9%) before the installation of the intensive care unit and 21/206 (10.2%) after the installation of the intensive care unit. Logistic regression analysis indicated that the probability of death after the installation of the intensive care unit decreased by 58% (OR: 0.42; 95%CI 0.205 -0.879; p = 0.021). Considering the limitations of the study, the results suggest a benefit, with a decrease of one death per every 11 patients treated for respiratory diseases after the installation of an intensive care unit in our hospital. The results corroborate the benefits of the implementation of intensive care units in secondary hospitals.

X-ray film calibration

International Nuclear Information System (INIS)

Stone, G.F.; Dittmore, C.H.; Henke, B.L.

1986-01-01

This paper discusses the use of silver halide x-ray films for imaging and spectroscopy which is limited by the range of intensities that can be recorded and densitometered. Using the manufacturers processing techniques can result in 10 2-3 range in intensity recorded over 0-5 density range. By modifying the chemistry and processing times, ranges of 10 5-6 can be recorded in the same density range. The authors report on x-ray film calibration work and dynamic range improvements. Changes to the processing chemistry and the resulting changes in dynamic range and x-ray sensitivity are discussed

AN XMM-NEWTON SURVEY OF THE SOFT X-RAY BACKGROUND. II. AN ALL-SKY CATALOG OF DIFFUSE O VII AND O VIII EMISSION INTENSITIES

International Nuclear Information System (INIS)

Henley, David B.; Shelton, Robin L.

2012-01-01

We present an all-sky catalog of diffuse O VII and O VIII line intensities, extracted from archival XMM-Newton observations. This catalog supersedes our previous catalog, which covered the sky between l = 120° and l = 240°. We attempted to reduce the contamination from near-Earth solar wind charge exchange (SWCX) emission by excluding times of high solar wind proton flux from the data. Without this filtering, we were able to extract measurements from 1868 observations. With this filtering, nearly half of the observations became unusable, and only 1003 observations yielded measurements. The O VII and O VIII intensities are typically ∼2-11 and ∼ –2 s –1 sr –1 (line unit, L.U.), respectively, although much brighter intensities were also recorded. Our data set includes 217 directions that have been observed multiple times by XMM-Newton. The time variation of the intensities from such directions may be used to constrain SWCX models. The O VII and O VIII intensities typically vary by ∼ 10 L.U. were observed. We compared our measurements with models of the heliospheric and geocoronal SWCX. The heliospheric SWCX intensity is expected to vary with ecliptic latitude and solar cycle. We found that the observed oxygen intensities generally decrease from solar maximum to solar minimum, both at high ecliptic latitudes (which is as expected) and at low ecliptic latitudes (which is not as expected). The geocoronal SWCX intensity is expected to depend on the solar wind proton flux incident on the Earth and on the sightline's path through the magnetosheath. The intensity variations seen in directions that have been observed multiple times are in poor agreement with the predictions of a geocoronal SWCX model. We found that the oxygen lines account for ∼40%-50% of the 3/4 keV X-ray background that is not due to unresolved active galactic nuclei, in good agreement with a previous measurement. However, we found that this fraction is not easily explainable by a

X-ray dosimetry of TlGaSe2 single crystals

International Nuclear Information System (INIS)

Kerimova, E.M.; Mustafaeva, S.N.; Mamedbeili, S.D.; Jabarov, J.N.; Iskenderova, P.M.; Kazimov, S.B.

2002-01-01

TlGaSe 2 compound belongs to group of layered semiconductors of A 3 B 3 C 2 6 -type. Photoelectric and optical properties of TlGaSe 2 single crystals were investigated in detail. Influence of gamma-, electron and neutron radiation on photoelectric properties of TlGaSe 2 single crystals is investigated too. The present work deals with experimental results relative to X-ray dosimetric characteristics of TlGaSe 2 crystals at 300 K. X-ray conductivity and X-ray dosimetric characteristic measurements are carried out in low load resistance regime. The source of X-ray radiation is the installation of X-ray diffraction analysis (URS-55a) with the BCV-2(Cu). Intensity of X-ray radiation (E) is regulated by measurement with current variation in tube at each given value of X-ray radiation dose E (R/min) are measured by crystal dosimeter DRGZ-02. X-ray conductivity coefficients K σ characterising X-ray sensitivity of investigated crystals are determined as the relative change of conductivity under X-ray radiation a per dose. There have been determined values of characteristic coefficients of TlGaSe 2 single crystal X-ray conductivity at different values of accelerating voltage (V a ) on the tube and corresponding doses of X-ray radiation. Analysis of obtained data showed that X-ray conductivity coefficients K σ in studied crystals are regularly decreased (from 0.276 to 0.033) as with the rise of dose (E=0.75-78.0 R/min) as with the increase of values of V a on X-ray tube (V a =254-50 keV). One of the possible reasons of observed regularities is that X-ray conductivity in investigated crystals, especially at comparatively low V a is due predominantly to radiation of thin layer of crystal. In this case with the rise of radiation intensity there have been started to prevail the mechanism of surface quadratic recombination which leads to observed decrease of X-ray conductivity. With the rise of accelerating potential 'effective hardness' is increased, as a result of which there

Diamonds in the rough: a strong case for the inclusion of weak-intensity X-ray diffraction data

International Nuclear Information System (INIS)

Wang, Jimin; Wing, Richard A.

2014-01-01

Here, new evidence is provided to show that the inclusion of weak-intensity, high-resolution X-ray diffraction data helps to improve the quality of experimental phases by imposing proper constraints on electron-density models during noncrystallographic symmetry averaging. Overwhelming evidence exists to show that the inclusion of weak-intensity, high-resolution X-ray diffraction data helps improve the refinement of atomic models by imposing strong constraints on individual and overall temperature B factors and thus the quality of crystal structures. Some researchers consider these data to be of little value and opt to discard them during data processing, particularly at medium and low resolution, at which individual B factors of atomic models cannot be refined. Here, new evidence is provided to show that the inclusion of these data helps to improve the quality of experimental phases by imposing proper constraints on electron-density models during noncrystallographic symmetry (NCS) averaging. Using electron-density correlation coefficients as criteria, the resolution of data has successfully been extended from 3.1 to 2.5 Å resolution with redundancy-independent merging R factors from below 100% to about 310%. It is further demonstrated that phase information can be fully extracted from observed amplitudes through de novo NCS averaging. Averaging starts with uniform density inside double-shelled spherical masks and NCS matrices that are derived from bound heavy-atom clusters at the vertices of cuboctahedrally symmetric protein particles

Classifying and assembling two-dimensional X-ray laser diffraction patterns of a single particle to reconstruct the three-dimensional diffraction intensity function: resolution limit due to the quantum noise

International Nuclear Information System (INIS)

Tokuhisa, Atsushi; Taka, Junichiro; Kono, Hidetoshi; Go, Nobuhiro

2012-01-01

A new algorithm is developed for reconstructing the high-resolution three-dimensional diffraction intensity function of a globular biological macromolecule from many quantum-noise-limited two-dimensional X-ray laser diffraction patterns, each for an unknown orientation. The structural resolution is expressed as a function of the incident X-ray intensity and quantities characterizing the target molecule. A new two-step algorithm is developed for reconstructing the three-dimensional diffraction intensity of a globular biological macromolecule from many experimentally measured quantum-noise-limited two-dimensional X-ray laser diffraction patterns, each for an unknown orientation. The first step is classification of the two-dimensional patterns into groups according to the similarity of direction of the incident X-rays with respect to the molecule and an averaging within each group to reduce the noise. The second step is detection of common intersecting circles between the signal-enhanced two-dimensional patterns to identify their mutual location in the three-dimensional wavenumber space. The newly developed algorithm enables one to detect a signal for classification in noisy experimental photon-count data with as low as ∼0.1 photons per effective pixel. The wavenumber of such a limiting pixel determines the attainable structural resolution. From this fact, the resolution limit due to the quantum noise attainable by this new method of analysis as well as two important experimental parameters, the number of two-dimensional patterns to be measured (the load for the detector) and the number of pairs of two-dimensional patterns to be analysed (the load for the computer), are derived as a function of the incident X-ray intensity and quantities characterizing the target molecule

Cosmic ray nucleonic intensity in low-amplitude days during the passage of high-speed solar wind streams

International Nuclear Information System (INIS)

Agarwal, R.; Mishra, R.K.; Tiwari, S.; or rm_jbp@yahoo.co.in

2008-01-01

One of the most striking features of solar wind is its organization into high- and low- speed streams. It is now well established that the passage over the Earth of high-speed solar wind streams leads to geomagnetic disturbances. The high-speed plasma streams are thus a key element in the complex chain of events that link geomagnetic activity to the solar activity and are therefore of great interest to the solar terrestrial physics. Two types of high-speed solar wind streams - coronal-hole-associated (or corotating) and flare-generated - were studied based on magnetic field and solar wind plasma parameters. In the work, the dependence was obtained for cosmic ray (CR) depressions due to high-speed solar wind streams during low-amplitude days. The CR nucleonic intensity data were subjected to the superposed epoch analysis with respect to the start time of high-speed solar wind streams. It was found that streams of both types produce significant deviations in the CR intensity during low-amplitude anisotropic wave train events. At the onset of such streams the CR intensity reaches its minimum during low-amplitude events and then increases statistically. (Authors)

Variation of photon intensities in transmitted photon spectra of 60Co as a function of dimensions of a soil medium

International Nuclear Information System (INIS)

Singh, Charanjeet; Sidhu, Gurdeep S.; Kumar, Ashok; Singh, Tejbir; Singh, Parjit S.; Mudahar, Gurmel S.

2005-01-01

The transmitted photon spectra of a point gamma-ray source of 60 Co have been measured through the longitudinal and transverse dimensions of a soil medium. The simultaneous effect of longitudinal and transverse thicknesses has been studied on the intensity of an appeared multiple-scatter peak in the soft part of the spectrum. The intensity of peak decreases exponentially with the increase of longitudinal thickness of soil medium whereas a reversal of the trend of multiple-scatter peak intensity with the transverse thickness observed as longitudinal dimension increases

X-ray filter for chest x-rays

International Nuclear Information System (INIS)

Ferlic, D.J.

1984-01-01

Filter for use in medical x-ray apparatus to permit higher intensity x-ray exposure in the heart and mediastinum area while maintaining a normal level of x-ray exposure in other areas of the body, particlarly in the lung area. The filter comprises a sheet of radiation absorbing material having an opening therein, said opening corresponding to the spine and central portion of the heart. Accordingly, the upper portion of the filter exhibits a relatively narrow opening which becomes gradually wider toward the lower portion of the filter

New determinations of gamma-ray line intensities of the E{sub p}=550 and 1747 keV resonances of the {sup 13}C(p,{gamma}){sup 14}N reaction

Energy Technology Data Exchange (ETDEWEB)

Kiener, J. E-mail: kiener@csnsm.in2p3.fr; Gros, M.; Tatischeff, V.; Attie, D.; Bailly, I.; Bauchet, A.; Chapuis, C.; Cordier, B.; Deloncle, I.; Porquet, M.G.; Schanne, S.; Sereville, N. de; Tauzin, G

2004-03-01

Gamma-ray angular distributions for the resonances at E{sub p}=550 and 1747 keV of the radiative capture reaction {sup 13}C(p,{gamma}){sup 14}N have been measured, using intense proton beams on isotopically pure {sup 13}C targets. Experimental gamma-ray spectra were obtained with three HP-Germanium detectors at four angles for E{sub p}=550 keV and six angles for E{sub p}=1747 keV in the range of 0-90 deg. with respect to the proton beam. From the data, relative intensities for the strongest transitions were extracted with an accuracy of typically 5%, making these resonances new useful gamma-ray standards for efficiency calibration in the energy range from E{sub {gamma}}=1.6-9 MeV. Gamma-ray branching ratios were obtained for several levels of {sup 14}N and are compared with literature values.

Use of high-intensity sonication for pre-treatment of biological tissues prior to multielemental analysis by total reflection X-ray fluorescence spectrometry

International Nuclear Information System (INIS)

De La Calle, Inmaculada; Costas, Marta; Cabaleiro, Noelia; Lavilla, Isela; Bendicho, Carlos

2012-01-01

In this work, two ultrasound-based procedures are developed for sample preparation prior to determination of P, K, Ca, Cr, Mn, Fe, Ni, Cu, Zn, As, Se and Sr in biological tissues by total reflection X-ray fluorescence spectrometry. Ultrasound-assisted extraction by means of a cup-horn sonoreactor and ultrasonic-probe slurry sampling were compared with a well-established procedure such as magnetic agitation slurry sampling. For that purpose, seven certified reference materials and different real samples of animal tissue were used. Similar accuracy and precision is obtained with the three sample preparation approaches tried. Limits of detection were dependent on both the sample matrix and the sample pre-treatment used, best values being achieved with ultrasound-assisted extraction. Advantages of ultrasound-assisted extraction include reduced sample handling, decreased contamination risks (neither addition of surfactants nor use of foreign objects inside the extraction vial), simpler background (no solid particles onto the sample carrier) and improved recovery for some elements such as P. A mixture of 10% v/v HNO 3 + 20–40% v/v HCl was suitable for extraction from biological tissues. - Highlights: ► We implement high-intensity sonication for pre-treatment of biological tissues. ► Multielemental analysis is performed by total reflection X-ray spectrometry. ► Ultrasound-based procedures are developed and compared to conventional slurry preparation. ► Features such as background, recovery and sample handling are favored by using ultrasonic extraction.

Conceptual design of a novel instrument for producing intense pulses of 10 ps X-rays for ultra-fast fluorescence measurements

Energy Technology Data Exchange (ETDEWEB)

Gruber, G.J.

1996-05-01

A novel bench-top device for producing intense, fast pulses of x-rays has been designed with 10 ps fwhm (full-width at half-maximum) x-ray pulse width, 120 keV maximum energy, 100 kHz repetition rate, and 1 A peak current onto the x-ray anode. The device includes three sections: (1) an electron gun that generates 5 ns wide pulses of 120 keV electrons at 100 kHz; (2) solenoidal magnetic lenses and deflection plates that focus the electrons onto an aperture plate and sweep the pulsed beam past the aperture, respectively; and (3) a tungsten anode onto which the post-aperture electrons are focused, producing pulses of x-rays. At a sweeping rate of 10{sup 13} V/s, the electron pulses and resulting x-ray pulses are reduced to about 10 ps. The design process used EGUN (an electron optics and gun design program) electron trajectory simulations, including calculation of important space charge effects. When built, this instrument will be used to excite new, fast, bright scintillator samples in crystal or powdered form, allowing fluorescent lifetimes and spectra to be measured with a microchannel PMT. The very narrow 10 ps x-ray pulse width is necessary for accurate measurements of the risetimes of very fast scintillators (e.g., BaF{sub 2}). In addition, the large x-ray flux (1 A peak current) is advantageous when using a reflection grating monochromator to measure decay times at different wavelengths.

Conceptual design of a novel instrument for producing intense pulses of 10 ps X-rays for ultra-fast fluorescence measurements

International Nuclear Information System (INIS)

Gruber, G.J.

1996-05-01

A novel bench-top device for producing intense, fast pulses of x-rays has been designed with 10 ps fwhm (full-width at half-maximum) x-ray pulse width, 120 keV maximum energy, 100 kHz repetition rate, and 1 A peak current onto the x-ray anode. The device includes three sections: (1) an electron gun that generates 5 ns wide pulses of 120 keV electrons at 100 kHz; (2) solenoidal magnetic lenses and deflection plates that focus the electrons onto an aperture plate and sweep the pulsed beam past the aperture, respectively; and (3) a tungsten anode onto which the post-aperture electrons are focused, producing pulses of x-rays. At a sweeping rate of 10 13 V/s, the electron pulses and resulting x-ray pulses are reduced to about 10 ps. The design process used EGUN (an electron optics and gun design program) electron trajectory simulations, including calculation of important space charge effects. When built, this instrument will be used to excite new, fast, bright scintillator samples in crystal or powdered form, allowing fluorescent lifetimes and spectra to be measured with a microchannel PMT. The very narrow 10 ps x-ray pulse width is necessary for accurate measurements of the risetimes of very fast scintillators (e.g., BaF 2 ). In addition, the large x-ray flux (1 A peak current) is advantageous when using a reflection grating monochromator to measure decay times at different wavelengths

Simultaneous X-ray, ultraviolet, and optical observations of the BL Lacertae object PKS 2155-304

International Nuclear Information System (INIS)

Treves, A.; Morini, M.; Chiappetti, L.; Fabian, A.; Falomo, R.

1989-01-01

A series of observations at optical, UV, and X-ray frequencies of PKS 2155-304, one of the brightest BL Lac objects is reported. Spectral fits given for various epochs show that the medium energy data are well fitted by single power laws plus absorption, with energy index between 1.5 and 2. Marginal evidence for an absorption edge at about 7 keV is found, as is evidence for some spectral depression at about 1 keV. This may be modeled with an edge at 660 + or - 26 eV with optical depth tau = 1.8 + or - 0.2. Energy distributions on several occasions are reconstructed, and the optical, UV, and X-ray intensities are found to be correlated in all cases but one. The variability amplitudes decrease and the time scales increase with decreasing frequency. These results indicate a synchrotron origin for the X-rays and distinct but connected emission regions for the X-ray, UV, and optical bands. 46 refs

Dihydropyridines decrease X-ray-induced DNA base damage in mammalian cells

Energy Technology Data Exchange (ETDEWEB)

Wojewodzka, M., E-mail: marylaw@ichtj.waw.pl [Center of Radiobiology and Biological Dosimetry, Institute of Nuclear Chemistry and Technology, Warszawa (Poland); Gradzka, I.; Buraczewska, I.; Brzoska, K.; Sochanowicz, B. [Center of Radiobiology and Biological Dosimetry, Institute of Nuclear Chemistry and Technology, Warszawa (Poland); Goncharova, R.; Kuzhir, T. [Institute of Genetics and Cytology, Belarussian National Academy of Sciences, Minsk (Belarus); Szumiel, I. [Center of Radiobiology and Biological Dosimetry, Institute of Nuclear Chemistry and Technology, Warszawa (Poland)

2009-12-01

Compounds with the structural motif of 1,4-dihydropyridine display a broad spectrum of biological activities, often defined as bioprotective. Among them are L-type calcium channel blockers, however, also derivatives which do not block calcium channels exert various effects at the cellular and organismal levels. We examined the effect of sodium 3,5-bis-ethoxycarbonyl-2,6-dimethyl-1,4-dihydropyridine-4-carboxylate (denoted here as DHP and previously also as AV-153) on X-ray-induced DNA damage and mutation frequency at the HGPRT (hypoxanthine-guanine phosphoribosyl transferase) locus in Chinese hamster ovary CHO-K1 cells. Using formamido-pyrimidine glycosylase (FPG) comet assay, we found that 1-h DHP (10 nM) treatment before X-irradiation considerably reduced the initial level of FPG-recognized DNA base damage, which was consistent with decreased 8-oxo-7,8-dihydro-2'-deoxyguanosine content and mutation frequency lowered by about 40%. No effect on single strand break rejoining or on cell survival was observed. Similar base damage-protective effect was observed for two calcium channel blockers: nifedipine (structurally similar to DHP) or verapamil (structurally unrelated). So far, the specificity of the DHP-caused reduction in DNA damage - practically limited to base damage - has no satisfactory explanation.

X-ray continuum and iron K emission line from the radio galaxy 3C 390.3

Science.gov (United States)

Inda, M.; Makishima, K.; Kohmura, Y.; Tashiro, M.; Ohashi, T.; Barr, P.; Hayashida, K.; Palumbo, G. G. C.; Trinchieri, G.; Elvis, M.

1994-01-01

X-ray properties of the radio galaxy 3C 390.3 were investigated using the European X-ray Observatory Satellite (EXOSAT) and Ginga satellites. Long-term, large-amplitude X-ray intensity changes were detected over a period extending from 1984 through 1991, and high-quality X-ray spectra were obtained especially with Ginga. The X-ray continuum spectra were described with power-law model with photon slope in the range 1.5-1.8, and the slope flattened as the 2-20 keV luminosity decreased by 40%. There was a first detection of the iron emission line from this source at the 90% confidence level. An upper limit was derived on the thermal X-ray component. X-ray emission mechanisms and possible origins of the long-term variation are discussed.

Temperature dependence of the electronic structure of Sr14Cu24O41 studied by resonant inelastic X-ray scattering

International Nuclear Information System (INIS)

Yoshida, M.; Ishii, K.; Ikeuchi, K.; Jarrige, I.; Murakami, Y.; Mizuki, J.; Tsutsui, K.; Tohyama, T.; Maekawa, S.; Kudo, K.; Koike, Y.; Endoh, Y.

2010-01-01

We report a resonant inelastic X-ray scattering (RIXS) study of charge excitations in the two-leg ladder Sr 14 Cu 24 O 41 . RIXS spectra at 1-5 eV are found to be dependent on temperature. An intraband excitation of the ladder, which appears as a continuum intensity below the Mott gap, decreases in intensity with temperature. Because the intraband excitation is related to the dynamics of doped holes in the ladder, its decrease of the intraband excitation is attributed to the reduction of the mobile holes in the ladder at low temperature.

Energy dependence of Lα-to-Ll x-ray intensity ratios for Yb and Pb produced by heavy-ion bombardment

International Nuclear Information System (INIS)

Gray, T.J.

1980-01-01

Measurements of the incident-ion energy dependence of Lα-to-Ll x-ray intensity ratios are reported for protons incident at 0.40 to 2.20 MeV/amu on thin targets of Pb and for 4 He and C ions incident upon Yb. The data are compared to calculations of the Lα-to-Ll ratio which include the effects of alignment of the 2p/sub 3/2/ state of the target

On the separation of split diffuse intensity maxima from a disordered Cu-Au alloy by an X-ray counter method

International Nuclear Information System (INIS)

Ohshima, K.I.; Harada, Jimpei; Moss, S.C.

1986-01-01

The X-ray diffuse scattering from a disordered Au-24.4 at.% Cu alloy was measured at room temperature to reveal the split diffuse maxima due to short-range ordering (SRO) through the use of a higher-resolution counter method than heretofore employed. Twofold and fourfold splittings of SRO diffuse intensity could be clearly seen at 100, 110 and their equivalent positions in reciprocal space. (orig.)

X-ray photoelectron spectroscopy study of synchrotron radiation irradiation of a polytetrafluoroethylene surface

CERN Document Server

Haruyama, Y; Matsui, S; Ideta, T; Ishigaki, H

2003-01-01

The effect of synchrotron radiation (SR) irradiation of a polytetrafluoroethylene (PTFE) surface was investigated using X-ray photoelectron spectroscopy (XPS). After the SR irradiation, the relative intensity of the F ls peak to the C ls peak decreased markedly. The chemical composition ratio to the F atoms to C atoms was estimated to be 0.29. From the curve fitting analysis of C ls and F ls XPS spectra, the chemical components and their intensity ratio were determined. The reason for the chemical composition change by the SR irradiation was discussed. (author)

The role of intensive phototherapy in decreasing the need for exchange transfusion in neonatal jaundice

International Nuclear Information System (INIS)

Edris, A.A.F.; Ghany, E.A.G.A.; Razek, A.R.A.A.

2014-01-01

Objectives: To assess the effectiveness of intensive phototherapy in reducing the need for exchange transfusion and the duration of phototherapy. Methods: The prospective study with historical controls was conducted at Cairo University Paediatric Hospital, from February to July 2012, and comprised 360 newborns with indirect hyperbilirubinaemia. The 183 subjects were treated with Bilisphere 360 (Bilisphere group) compared with 177 who had been treated with conventional phototherapy (control group). Both groups were subjected to complete clinical evaluation and laboratory investigations. Results: Bilisphere 360 decreased the need for exchange transfusion in 19 (10.4%) neonates of the Bilisphere group versus 130 (73.4%) of the control group (p<0.001); decreased the level of serum bilirubin as exchange transfusion (6.7 mg/dl (24.9%) in the subjects vs. 6.9 mg/dl (22.7%) in the controls); shortened the duration of phototherapy (2.7 days in the subjects, vs. 4.2 days in the controls; p<0.001). Conclusion: The use of Bilisphere 360 in the treatment of indirect pathological hyperbilirubinaemia is as effective as exchange transfusion in lowering Total Serum Bilirubin when its level is within 2-3 mg/dl (34-51umol/l) of the exchange level. Bilisphere 360 is effective in reducing needs for exchange transfusion and duration of phototherapy. (author)

Effect of powder sample granularity on fluorescent intensity and on thermal parameters in x-ray diffraction Rietveld analysis

International Nuclear Information System (INIS)

Sparks, C.J.; Specht, E.D.; Ice, G.E.; Kumar, R.; Zschack, P.; Shiraishi, T.; Hisatsune, K.

1991-01-01

The effect of sample granularity on diffracted x-ray intensity was evaluated by measuring the 2θ dependence of x-ray fluorescence from various samples. Measurements were made in the symmetric geometry on samples ranging from single crystals to highly absorbing coarse powders. A characteristic shape for the absorption correction was observed. A demonstration of the sensitivity of Rietveld refined site occupation parameters is made on CuAu and Cu 50 Au 44 Ni 6 alloys refined with and without granularity corrections. These alloys provide a good example of the effect of granularity due to their large linear x-ray absorption coefficients. Sample granularity and refined thermal parameters obtained from the Rietveld analysis were found to be correlated. Without a granularity correction, the refined thermal parameters are too low and can actually become negative in an attempt to compensate for granularity. A general shape for granularity correction can be included in refinement procedures. If no granularity correction is included, data should be restricted to above 30 degrees 2θ, and thermal parameters should be ignored unless extreme precautions are taken to produce >5 μm particles and high packing densities

Catalog of gamma-rays unplaced in radioactive decay schemes

International Nuclear Information System (INIS)

Narita, Tsutomu; Kitao, Kensuke.

1991-03-01

A catalog is made for gamma-rays emitted in decay of radioactive nuclides but not placed in their decay schemes. It consists of two tables. In Table 1, the number of these unplaced gamma-ray components by a nuclide is given together with the fraction of total intensity of these gamma-rays to that of all observed gamma-rays. In Table 2, the unplaced gamma-rays are arranged in order of increasing energy. Each line of this table contains the gamma-ray energy, intensity, nuclide identification, and energies and intensities of the most prominent gamma-rays from the decay of the radionuclides. This catalog is a compilation from Evaluated Nuclear Structure Data File (ENSDF) maintained by National Nuclear Data Center at Brookhaven National Laboratory, of at February 1990. (author)

X-ray imaging with compound refractive lens and microfocus X-ray tube

OpenAIRE

Pina, Ladislav; Dudchik, Yury; Jelinek, Vaclav; Sveda, Libor; Marsik, Jiri; Horvath, Martin; Petr, Ondrej

2008-01-01

Compound refractive lenses (CRL), consisting of a lot number in-line concave microlenses made of low-Z material were studied. Lenses with focal length 109 mm and 41 mm for 8-keV X-rays, microfocus X-ray tube and X-ray CCD camera were used in experiments. Obtained images show intensity distribution of magnified microfocus X-ray source focal spot. Within the experiments, one lens was also used as an objective lens of the X-ray microscope, where the copper anode X-ray microfocus tube served as a...

Decreased TK activity alters growth, yield and tolerance to low temperature and low light intensity in transgenic cucumber plants.

Science.gov (United States)

Bi, Huangai; Dong, Xubing; Wu, Guoxiu; Wang, Meiling; Ai, Xizhen

2015-02-01

Four CsTK antisense transgenic cucumber plants were obtained. Decreased TK activity decreased the photosynthetic rate, seed germination rate, growth yield, and the tolerance to low temperature and weak light stress. Transketolase (TK, EC 2.2.1.1) is a key enzyme in the photosynthetic carbon reduction cycle (Calvin cycle). A cDNA fragment (526 bp) encoding transketolase was cloned from cucumber plants (Cucumis sativa L. cv 'Jinyou 3') by RT-PCR. The antisense expression [(PBI-CsTK(-)] vector containing the CsTK gene fragment was constructed. The resulting plasmid was introduced into the cucumber inbred lines '08-1' using the agrobacterium-mediated method, and four antisense transgenic cucumber plants were obtained. Decreased CsTK expression either unaltered or slightly increased the mRNA abundance and activities of the other main enzymes in the Calvin cycle, however, it decreased the TK activity and net photosynthetic rate (Pn) in antisense transgenic cucumber leaves. Antisense plants showed decreases in the growth, ratio of female flowers and yield compared with the wild-type (WT) plants. The decrease in Pn, stomatal conductance (Gs), transpiration rate (Tr), photochemical efficiency (Fv/Fm) and actual photochemical efficiency of PSII (ΦPSII) and the increase in electrolyte leakage (EL) were greater in antisense transgenic plants than in WT plants under low temperature (5 °C) and low light intensity (100 μmol m(-2) s(-1)).

Development of Compton X-ray spectrometer for high energy resolution single-shot high-flux hard X-ray spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Kojima, Sadaoki, E-mail: kojima-s@ile.osaka-u.ac.jp, E-mail: sfujioka@ile.osaka-u.ac.jp; Ikenouchi, Takahito; Arikawa, Yasunobu; Sakata, Shohei; Zhang, Zhe; Abe, Yuki; Nakai, Mitsuo; Nishimura, Hiroaki; Shiraga, Hiroyuki; Fujioka, Shinsuke, E-mail: kojima-s@ile.osaka-u.ac.jp, E-mail: sfujioka@ile.osaka-u.ac.jp; Azechi, Hiroshi [Institute of Laser Engineering, Osaka University, 2-6 Yamada-oka, Suita, Osaka 565-0871 (Japan); Ozaki, Tetsuo [National Institute for Fusion Science, 322-6 Oroshi, Toki, Gifu 509-5292 (Japan); Miyamoto, Shuji; Yamaguchi, Masashi; Takemoto, Akinori [Laboratory of Advanced Science and Technology for Industry, University of Hyogo, 3-1-2 Kouto, Kamigori-cho, Ako-gun, Hyogo 678-1205 (Japan)

2016-04-15

Hard X-ray spectroscopy is an essential diagnostics used to understand physical processes that take place in high energy density plasmas produced by intense laser-plasma interactions. A bundle of hard X-ray detectors, of which the responses have different energy thresholds, is used as a conventional single-shot spectrometer for high-flux (>10{sup 13} photons/shot) hard X-rays. However, high energy resolution (Δhv/hv < 0.1) is not achievable with a differential energy threshold (DET) X-ray spectrometer because its energy resolution is limited by energy differences between the response thresholds. Experimental demonstration of a Compton X-ray spectrometer has already been performed for obtaining higher energy resolution than that of DET spectrometers. In this paper, we describe design details of the Compton X-ray spectrometer, especially dependence of energy resolution and absolute response on photon-electron converter design and its background reduction scheme, and also its application to the laser-plasma interaction experiment. The developed spectrometer was used for spectroscopy of bremsstrahlung X-rays generated by intense laser-plasma interactions using a 200 μm thickness SiO{sub 2} converter. The X-ray spectrum obtained with the Compton X-ray spectrometer is consistent with that obtained with a DET X-ray spectrometer, furthermore higher certainly of a spectral intensity is obtained with the Compton X-ray spectrometer than that with the DET X-ray spectrometer in the photon energy range above 5 MeV.

Correction factors for {gamma}-ray relative intensities in the {sup 66}Ga radioisotope

Energy Technology Data Exchange (ETDEWEB)

Schmid, G.J. [Duke Univ., Durham, NC (United States)]|[Triangle Universities Nuclear Lab., Durham, NC (United States); Chasteler, R.M. [Duke Univ., Durham, NC (United States)]|[Triangle Universities Nuclear Lab., Durham, NC (United States); Laymon, C.M. [Duke Univ., Durham, NC (United States)]|[Triangle Universities Nuclear Lab., Durham, NC (United States); Weller, H.R. [Duke Univ., Durham, NC (United States)]|[Triangle Universities Nuclear Lab., Durham, NC (United States); Moore, E.F. [Triangle Universities Nuclear Lab., Durham, NC (United States)]|[North Carolina State Univ., Raleigh, NC (United States); Bybee, C.R. [Triangle Universities Nuclear Lab., Durham, NC (United States)]|[North Carolina State Univ., Raleigh, NC (United States); Drake, J.M. [Triangle Universities Nuclear Lab., Durham, NC (United States)]|[North Carolina State Univ., Raleigh, NC (United States); Tilley, D.R. [Triangle Universities Nuclear Lab., Durham, NC (United States)]|[North Carolina State Univ., Raleigh, NC (United States); Vavrina, G. [Triangle Universities Nuclear Lab., Durham, NC (United States)]|[North Carolina State Univ., Raleigh, NC (United States); Wallace, P.M. [Triangle Universities Nuclear Lab., Durham, NC (United States)]|[North Carolina State Univ., Raleigh, NC (United States)

1996-09-16

We present here strong evidence that recently published values for the relative intensities of {gamma}-ray lines in the {sup 66}Ga({beta}{sup +}+EC){sup 66}Zn decay are incorrect at the higher energies ({proportional_to}30% too low at 4.8 MeV). In particular, we find that our current results are consistent with a set of correction factors which were first suggested 20 years ago, but have gone largely ignored until now. Our validation of these little known correction factors will have bearing on experiments which use the {sup 66}Ga radioisotope to extrapolate absolute detector efficiencies to higher energies. In particular, we discuss the conclusions of a recent D(p, {gamma}){sup 3}He experiment which will be strongly affected by our current results. The astrophysical S-factor data derived from this D(p, {gamma}){sup 3}He experiment are now seen to be systematically too low by {proportional_to}30%. (orig.).

Measurement of the noise components in the medical x-ray intensity pattern due to overlaying nonrecognizable structures

Science.gov (United States)

Tischenko, Oleg; Hoeschen, Christoph; Effenberger, Olaf; Reissberg, Steffen; Buhr, Egbert; Doehring, Wilfried

2003-06-01

There are many aspects that influence and deteriorate the detection of pathologies in X-ray images. Some of those are due to effects taking place in the stage of forming the X-ray intensity pattern in front of the x-ray detector. These can be described as motion blurring, depth blurring, anatomical background, scatter noise and structural noise. Structural noise results from an overlapping of fine irrelevant anatomical structures. A method for measuring the combined effect of structural noise and scatter noise was developed and will be presented in this paper. This method is based on the consideration that within a pair of projections created after rotation of the object with a small angle (which is within the typical uncertainty in positioning the patient) both images would show the same relevant structures whereas the projection of the fine overlapping structures will appear quite differently in the two images. To demonstrate the method two X-ray radiographs of a lung phantom were produced. The second radiograph was achieved after rotating the lung by an angle of about 3. Dyadic wavelet representations of both images were regarded. For each value of the wavelet scale parameter the corresponding pair of approximations was matched using the cross correlation matching technique. The homologous regions of approximations were extracted. The image containing only those structures that appear in both images simultaneously was then reconstructed from the wavelet coefficients corresponding to the homologous regions. The difference between one of the original images and the noise-reduced image contains the structural noise and the scatter noise.

Flat Field Anomalies in an X-ray CCD Camera Measured Using a Manson X-ray Source (HTPD 08 paper)

International Nuclear Information System (INIS)

Haugh, M; Schneider, M B

2008-01-01

The Static X-ray Imager (SXI) is a diagnostic used at the National Ignition Facility (NIF) to measure the position of the X-rays produced by lasers hitting a gold foil target. The intensity distribution taken by the SXI camera during a NIF shot is used to determine how accurately NIF can aim laser beams. This is critical to proper NIF operation. Imagers are located at the top and the bottom of the NIF target chamber. The CCD chip is an X-ray sensitive silicon sensor, with a large format array (2k x 2k), 24 (micro)m square pixels, and 15 (micro)m thick. A multi-anode Manson X-ray source, operating up to 10kV and 10W, was used to characterize and calibrate the imagers. The output beam is heavily filtered to narrow the spectral beam width, giving a typical resolution E/ΔE ∼ 10. The X-ray beam intensity was measured using an absolute photodiode that has accuracy better than 1% up to the Si K edge and better than 5% at higher energies. The X-ray beam provides full CCD illumination and is flat, within ±1% maximum to minimum. The spectral efficiency was measured at 10 energy bands ranging from 930 eV to 8470 eV. We observed an energy dependent pixel sensitivity variation that showed continuous change over a large portion of the CCD. The maximum sensitivity variation occurred at 8470 eV. The geometric pattern did not change at lower energies, but the maximum contrast decreased and was not observable below 4 keV. We were also able to observe debris, damage, and surface defects on the CCD chip. The Manson source is a powerful tool for characterizing the imaging errors of an X-ray CCD imager. These errors are quite different from those found in a visible CCD imager

Hard X-ray measurements of A0535+26 during low state

International Nuclear Information System (INIS)

Polcaro, V.F.; Bazzano, A.; La Padula, C.; Ubertini, P.; Vialetto, G.

1982-01-01

A number of measurements of the recurrent transient X-ray source A0535+26 have been made during its outburst phase, since its detection in 1975 by Ariel V. The optical counterpart of the source (Be Star 245770) has also been extensively studied both in active and quiescent state in optical I.R. and U.V. bands. These data show a positive correlation with the X-ray flux during on state. The X-ray flux from the source during the outburst increases to about twice the Crab intensity in soft X-ray band and gradually decreases to 100 mCrab during 30 to 50 days. However positive detection of the sources has not been reported until now during the low state. In this paper we present the spectral measurements of the source in the energy band 20-100 KeV made during the low state in 1981. (orig.)

Evaluation of super intense geomagnetic storms and related structures of the interplanetary medium through the observation of cosmic rays of high energy surface; Analise de tempestades geomagneticas super intensas e de estruturas do meio interplanetario relacionadas, atraves da observacao de raios cosmicos de superficie de alta energia

Energy Technology Data Exchange (ETDEWEB)

Savian, Jairo Francisco; Schuch, Nelson J., E-mail: savian@lacesm.ufsm.br, E-mail: njschuch@lacesm.ufsm.br [Centro Regional Sul de Pesquisas Espaciais - CRSPE/INPE-MCT, Santa Maria, RS (Brazil); Silva, Marlos Rockenbach da; Lago, Alisson dal; Gonzalez, Walter Demetrio, E-mail: marlos@dge.inpe.br, E-mail: dallago@dge.inpe.br, E-mail: gonzalez@dge.inpe.br [Instituto Nacional de Pesquisas Espaciais - INPE-MCT, Sao Jose dos Campos, SP (Brazil); Munakata, Kazuoki [Physics Department, Shinshu University, Matsumoto (Japan)

2005-04-15

It is believed that the physical mechanism responsible for the transference of energy from the solar wind to the Earth magnetosphere is the reconnection between the interplanetary magnetic field and the terrestrial magnetic field (Tsurutani and Gonzalez, 1997). The necessary criterion for a intense geomagnetic storms to occur, Dst < -100nT, is the existence of a dawn-dusk interplanetary electric field larger than 5 mV/m, for a period larger than 3 hours. Cosmic rays have been studied as a natural phenomenon that can tell much about both Earth's environment in space and distant astrophysical processes (Jokipii, 2000). A solar disturbance propagating away from the Sun affects the pre-existing population of galactic cosmic rays in a number of ways. The most famous one is known as the 'Forbush decrease', which is a suppression of ground cosmic-ray counts observed during geomagnetic disturbances. The objective of this work is to study the response of the Southern Space Observatory ground Muon Telescope observations, installed in Sao Martinho da Serra, RS, Brazil, to 3 super intense geomagnetic storms, combining observation provided by L1 satellites and ground detectors. (author)

X-ray generation by femtosecond laser pulses and its application to soft X-ray imaging microscope

International Nuclear Information System (INIS)

Ikeda, Kenichi; Kotaki, Hideyuki; Nakajima, Kazuhisa

2002-01-01

We have developed laser-produced plasma X-ray sources using femtosecond laser pulses at 10Hz repetition rate in a table-top size in order to investigate basic mechanism of X-ray emission from laser-matter interactions and its application to a X-ray microscope. In a soft X-ray region over 5 nm wavelength, laser-plasma X-ray emission from a solid target achieved an intense flux of photons of the order of 1011 photons/rad per pulse with duration of a few 100 ps, which is intense enough to make a clear imaging in a short time exposure. As an application of laser-produced plasma X-ray source, we have developed a soft X-ray imaging microscope operating in the wavelength range around 14 nm. The microscope consists of a cylindrically ellipsoidal condenser mirror and a Schwarzshird objective mirror with highly-reflective multilayers. We report preliminary results of performance tests of the soft X-ray imaging microscope with a compact laser-produced plasma X-ray source

Characteristics of x-ray radiation from a gas-puff z-pinch plasma

International Nuclear Information System (INIS)

Akiyama, N.; Takasugi, K.

2002-01-01

Characteristics of x-ray radiation from Ar gas-puff z-pinch plasma have been investigated by changing delay time of discharge from gas puffing. Intense cloud structure of x-ray image was observed at small delay time region, but the total x-ray signal was not so intense. The x-ray signal increased with increasing the delay time, and hot spots of x-ray image also became intense. Electron temperature was evaluated from x-ray spectroscopic data, and no significant difference in temperature was observed. (author)

THE CONTRIBUTION OF X-RAY BINARIES TO THE EVOLUTION OF LATE-TYPE GALAXIES: EVOLUTIONARY POPULATION SYNTHESIS SIMULATIONS

International Nuclear Information System (INIS)

Zuo Zhaoyu; Li Xiangdong

2011-01-01

X-ray studies of normal late-type galaxies have shown that non-nuclear X-ray emission is typically dominated by X-ray binaries and provides a useful measure of star formation activity. We have modeled the X-ray evolution of late-type galaxies over the ∼14 Gyr of cosmic history, with an evolutionary population synthesis code developed by Hurley et al. Our calculations reveal a decrease in the X-ray luminosity-to-mass ratio L X /M with time, in agreement with observations. We show that this decrease is a natural consequence of stellar and binary evolution and the mass accumulating process in galaxies. The X-ray-to-optical luminosity ratio L X /L B is found to be fairly constant (around ∼10 30 erg s -1 L -1 B,sun ) and insensitive to the star formation history in the galaxies. The nearly constant value of L X /L B is in conflict with the observed increase in L X /L B from z = 0 to 1.4. The discrepancy may be caused by intense obscured star formation activity that leads to a nonlinear relationship between X-ray and B-band emission.

Development of improved x-ray optics for analytical x-ray microbeams. CRADA final report for CRADA Number Y-1294-0283

International Nuclear Information System (INIS)

Carpenter, D.A.; Gao, N.; Xiao, Q.F.; Ponomarev, I.

1996-01-01

The purpose of this CRADA was to develop improved glass capillary, x-ray optics for analytical x-ray microbeam applications. X-Ray Optical Systems, Inc. (XOS) designed and fabricated capillary optics and LMES tested those optics for x-ray microanalytical applications using its unique X-Ray Microprobe. Tapered capillaries with 3-microm and 8-microm output openings were fabricated and tested. The tapered capillaries had better spectral quality for x-ray microfluorescence (XRMF) analysis, than non-tapered, straight capillaries that are currently used in the system. X-ray beam count-rates for the tapered capillaries were also greater than the straight capillaries. Two monolithic, polycapillary optics were fabricated and tested. The polycapillary optics produced focal spots of 40 and 100 microm. Beam intensities for the polycapillaries were, respective, 44 and 18 times the intensities found in straight 50-microm and 100-microm capillaries. High-sensitivity scanning will be possible because of the enhanced intensity of the polycapillary optic. LMES and the DP program will benefit from improved capabilities for nondestructive x-ray microanalysis, while XOS will benefit from test results that will enhance the marketability of their products

Prediction of galactic cosmic ray intensity variation for a few (up to 10-12 years ahead on the basis of convection-diffusion and drift model

Directory of Open Access Journals (Sweden)

L. I. Dorman

2005-11-01

Full Text Available We determine the dimension of the Heliosphere (modulation region, radial diffusion coefficient and other parameters of convection-diffusion and drift mechanisms of cosmic ray (CR long-term variation, depending on particle energy, the level of solar activity (SA and general solar magnetic field. This important information we obtain on the basis of CR and SA data in the past, taking into account the theory of convection-diffusion and drift global modulation of galactic CR in the Heliosphere. By using these results and the predictions which are regularly published elsewhere of expected SA variation in the near future and prediction of next future SA cycle, we may make a prediction of the expected in the near future long-term cosmic ray intensity variation. We show that by this method we may make a prediction of the expected in the near future (up to 10-12 years, and may be more, in dependence for what period can be made definite prediction of SA galactic cosmic ray intensity variation in the interplanetary space on different distances from the Sun, in the Earth's magnetosphere, and in the atmosphere at different altitudes and latitudes.

Study of solar activity by measuring cosmic rays with a water Cherenkov detector

International Nuclear Information System (INIS)

Bahena Bias, Angelica; Villasenor, Luis

2011-01-01

We report on an indirect study of solar activity by using the Forbush effect which consists on the anti-correlation between the intensity of solar activity and the intensity of secondary cosmic radiation detected at ground level at the Earth. We have used a cylindrical water Cherenkov detector to measure the rate of arrival of secondary cosmic rays in Morelia Mich., Mexico, at 1950 m.a.s.l. We describe the analysis required to unfold the effect of atmospheric pressure and the search for Forbush decreases in our data, the latter correspond to more than one year of continuous data collection.

Conceptual design of a novel instrument for producing intense pulses of 10 ps X-rays for ultra-fast fluorescence measurements

International Nuclear Information System (INIS)

Gruber, G.J.; Derenzo, S.E.

1996-01-01

A novel bench-top device for producing intense, fast pulses of x-rays has been designed with 10 ps fwhm (full-width at half-maximum) x-ray pulse width, 120 keV maximum energy, 100 kHz repetition rate, and 1 A peak current onto the x-ray anode. The device includes three sections: (1) an electron gun that generates 5 ns wide pulses of 120 keV electrons at 100 kHz; (2) solenoidal magnetic lenses and deflection plates that focus the electrons onto an aperture plate and sweep the pulsed beam past the aperture, respectively; and (3) a tungsten anode onto which the post-aperture electrons are focused, producing pulses of x-rays. Using solenoidal magnetic lenses with a cur-rent density of 150 A·turns/cm 2 to focus the electron beam, a deflection plate dV/dt of 10 13 V/s is needed to achieve electron pulse widths of about 10 ps. The design process used EGUN (an electron optics and gun design program) electron trajectory simulations, including calculation of important space charge effects. When built, this instrument will be used to excite scintillator samples in crystal or powdered form, allowing fluorescent lifetimes and spectra to be measured with a microchannel PMT. The very narrow 10 ps x-ray pulse width is necessary for accurate measurements of the risetimes of very fast scintillators, (e.g., BaF 2 ). In addition, the large x-ray flux (1 A peak current) is advantageous when using a reflection grating monochromator to measure decay times at different wavelengths

The self-absorption effect of gamma rays in 239Pu

International Nuclear Information System (INIS)

Hsiaohua Hsu

1989-01-01

Nuclear materials assay with gamma-ray spectrum measurement is a well-established method for safeguards. However, for a thick source, the self-absorption of characteristic low-energy gamma rays has been a handicap to accurate assay. The author has carried out Monte Carlo simulations to study this effect using the 239 Pu α-decay gamma-ray spectrum as an example. The thickness of a plutonium metal source can be considered a function of gamma-ray intensity ratios. In a practical application, gamma-ray intensity ratios can be obtained from a measured spectrum. With the help of calculated curves, scientists can find the source thickness and make corrections to gamma-ray intensities, which then lead to an accurate quantitative determination of radioactive isotopes in the material

Valence-electron configuration of Fe, Cr, and Ni in binary and ternary alloys from Kβ -to- Kα x-ray intensity ratios

Science.gov (United States)

Han, I.; Demir, L.

2009-11-01

Kβ -to- Kα x-ray intensity ratios of Fe, Cr, and Ni have been measured in pure metals and in alloys of FexNi1-x ( x=0.8 , 0.7, 0.6, 0.5, 0.4, 0.3, and 0.2), NixCr1-x ( x=0.8 , 0.6, 0.5, 0.4, and 0.2), FexCr1-x ( x=0.9 , 0.7, and 0.5), and FexCryNi1-(x+y) ( x=0.7-y=0.1 , x=0.5-y=0.2 , x=0.4-y=0.3 , x=0.3-y=0.3 , x=0.2-y=0.2 , and x=0.1-y=0.2 ) following excitation by 22.69 keV x rays from a 10 mCi C109d radioactive point source. The valence-electron configurations of these metals were determined by corporation of measured Kβ -to- Kα x-ray intensity ratios with the results of multiconfiguration Dirac-Fock calculation for various valence-electron configurations. Valence-electron configurations of 3d transition metals in alloys indicate significant differences with respect to the pure metals. Our analysis indicates that these differences arise from delocalization and/or charge transfer phenomena in alloys. Namely, the observed change of the valence-electron configurations of metals in alloys can be explained with the transfer of 3d electrons from one element to the other element and/or the rearrangement of electrons between 3d and 4s,4p states of individual metal atoms.

Relativistic self-focusing of ultra-high intensity X-ray laser beams in warm quantum plasma with upward density profile

International Nuclear Information System (INIS)

Habibi, M.; Ghamari, F.

2014-01-01

The results of a numerical study of high-intensity X-ray laser beam interaction with warm quantum plasma (WQP) are presented. By means of an upward ramp density profile combined with quantum factors specially the Fermi velocity, we have demonstrated significant relativistic self-focusing (RSF) of a Gaussian electromagnetic beam in the WQP where the Fermi temperature term in the dielectric function is important. For this purpose, we have considered the quantum hydrodynamics model that modifies refractive index of inhomogeneous WQPs with the inclusion of quantum correction through the quantum statistical and diffraction effects in the relativistic regime. Also, to better illustration of the physical difference between warm and cold quantum plasmas and their effect on the RSF, we have derived the envelope equation governing the spot size of X-ray laser beam in Q-plasmas. In addition to the upward ramp density profile, we have found that the quantum effects would be caused much higher oscillation and better focusing of X-ray laser beam in the WQP compared to that of cold quantum case. Our computational results reveal the importance of the use of electrons density profile and Fermi speed in enhancing self-focusing of laser beam

Fission products determination in high activity waste solution by wavelength dispersive X-ray fluorescence spectral interference correction by intensity ratio

International Nuclear Information System (INIS)

Sato, I.M.

1988-01-01

Fission products Se, Rb, Y, Zr, Mo, Ru, Rh, Pd, Te, Cd, Cs, Ba, La, Ce, Pr, Nd, Sm, Eu and Gd were determined in simulated high activity radioactive waste solution by wavelength dispersive X-ray fluorescence spectrometry without chemical separation. Thin layer technique was employed for the sample preparation. For the L spectral lines, the absorption effect was verified by Rasberry-Heinrich, Lucas Tooth-Pyne and Lachance-Trail relations. This effect was quantified and corrected accordingly. The spectral interferences of Kα and/or Lα lines of Y, Zr, Mo, La, Ce, Pr, Nd, Sm, Eu and Gd elements were eliminated by the intensity ratio method. The overlapping of up to three analytical lines was corrected by applying this method. The concentration influence of the interfering element on the intensity ratio values as well the efficiency of the correction method were investigated in order to assure that no systematic or residual error, resulting from the correction, affect the actual fluorescent intensity determination. The results is compared with the data obtained from measurements of free lines of spectral interference and also with those obtained by the linear equation system. Fission products determination presented a precision in the range of 0.1 to 5.0% and an accuracy of up to ± 7.0% the results are compared with those obtained by neutron activation analysis and inductively coupled plasma - atomic emission spectrometry. Leaching data, when radioactive waste is incorporated in cement matrix, were attempted by X-ray fluorescence technique. For two years leaching period, leaching rate and diffusion coefficient data of cesium were determined. The results obtained agree with those obtained by γ-spectromety. (author) [pt

Millianalyser by x-ray fluorescence

International Nuclear Information System (INIS)

Kawamoto, A.; Hirao, O.; Kashiwakura, J.; Gohshi, Y.

1976-01-01

Research on the possibility of mm-size nondestructive analysis was carried out by the fluorescent x-ray method. With 0.2 mm pin-hole slit, source x-rays from a Cu target diffraction tube were collimated to a spot smaller than 1 mm phi at a slide stage placed about 5 cm distant from the pin-hole slit. Resultant x-rays from a sample placed on the slide stage, which is excited by the collimated x-ray, were detected with a head-on-type 6 mm SSD, placed so that its 12.5 micron Be window was about 5 cm beneath the stage. X-ray intensities sufficient for analysis (500 to 5000 CPS) could be obtained for various metallic samples with up to 40 kV-10 mA excitation. This instrument proved to be useful for mm-size qualitative analysis in measurements of tiny samples. Furthermore, the possibility of distribution analysis is expected based on the result of an investigation on c.a. 0.1 percent Cr in LiNbO 3 , where the ratios of Cr-Kα intensity to scattered Cu-Kα intensity varied between 0.094 and 0.19, with deviations of less than 7.5 percent at five successive points located at 2 mm intervals along the direction of growth

Secular variation of cosmic ray intensity recorded in the radiocarbon concentration of tree rings

International Nuclear Information System (INIS)

Kigoshi, K.

1978-01-01

Study of the secular variations of cosmic ray intensity on the basis of the secular variations of atmospheric radiocarbon concentration in 8000 years is considered. The data on the radiocarbon concentration is received by three laboratories using the dendrochronologically dated tree ring samples. In order to use the data the variations due to geochemical process must be eliminated. From this point of view the climatic effect on the atmospheric radiocarbon concenttration is estimated using the data on sunspot number and global surface temperature during 1650-1800 y. The barge influence of climate on the atmospheric radiocarbon concentration syggests the small contribution of change of radiocarbon production rate to the short-period fluctuations in the atmospheric radiocarbon concentration. Elimination of variations caused by climate and sunspot activities from the variations in atmospheric radiocarbon concentration gives a long-term scale of its concentration which agrees well to the observed paleo-geomagnetic data

Miniature x-ray point source for alignment and calibration of x-ray optics

International Nuclear Information System (INIS)

Price, R.H.; Boyle, M.J.; Glaros, S.S.

1977-01-01

A miniature x-ray point source of high brightness similar to that of Rovinsky, et al. is described. One version of the x-ray source is used to align the x-ray optics on the Argus and Shiva laser systems. A second version is used to determine the spatial and spectral transmission functions of the x-ray optics. The spatial and spectral characteristics of the x-ray emission from the x-ray point source are described. The physical constraints including size, intensity and thermal limitations, and useful lifetime are discussed. The alignment and calibration techniques for various x-ray optics and detector combinations are described

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.

Generation and application of 15 to 30 MeV parametric X-ray by linac

CERN Document Server

Akimoto, T

2002-01-01

15 to 30 MeV parametric X-ray (PXR) was generated using Si single crystal by 45 MeV electron LINAC. To obtain good monochromatic hard X-ray field, the appropriate conditions were determined by theoretical analysis and experiments. The intensity of PXR was increased with increasing electron energy and crystal rotation angle. However, PXR energy is independent of electron energy. By increasing measurement angle, energy of PXR decreased, but its intensity increased. 15 to 30 keV PXR energy and about 10 sup - sup 5 to 10 sup - sup 6 photon/electron of intensity were observed at 15 to 22 deg detection angle under the operation conditions of 45 MeV electron energy and 4 to 8 nA of beam current. The mass attenuation coefficient of photon of Zr, Nb and Mo, in K absorption edge was measured. Application to determine lattice distortion of target sample and off-angle of crystal was investigated. Generation and detection of PXR, measurement of characteristic properties: crystal rotation angle, detection angle, electron e...

Retracted-Enhanced X-Ray Absorption Property of Gold-Doped Single Wall Carbon Nanotube

Directory of Open Access Journals (Sweden)

Alimin Alimin

2015-11-01

Full Text Available Enhanced X-ray absorption property of single wall carbon nanotube (SWCNT through gold (Au doping (Au@SWCNT has been studied. Mass attenuation coefficient of SWCNT increased 5.2-fold after Au doping treatment. The use of ethanol in the liquid phase adsorption could produce Au nanoparticles as confirmed by the X-ray Diffraction (XRD patterns. The possibility of gold nanoparticles encapsulated in the internal tube space of SWCNT was observed by transmission electron microscope technique. A significant decrease of nitrogen uptakes and upshifts of Radial Breathing Mode (RBM of Au@SWCNT specimen suggest that the nanoparticles might be encapsulated in the internal tube spaces of the nanotube. In addition, a decrease intensity of XRD pattern of Au@SWCNT at around 2θ ≈ 2.6° supports the suggestion that Au nanoparticles are really encapsulated into SWCNT.

Preparation of a liquid nitrogen target for measurement of γ-ray in the 14N(n,γ)15N reaction as an intensity standard in energy region up to 11 MeV

International Nuclear Information System (INIS)

Hirano, M.; Obayashi, H.; Sakane, H.; Shibata, M.; Kawade, K.; Taniguchi, A.

2001-01-01

For determination of relative γ-ray intensities up to 11 MeV in the 14 N(n,γ) 15 N reaction, we have developed a liquid nitrogen (N 2 ) target which contain no hydrogen (H) to improve the accuracy of γ-ray intensities. The ratio of the relative uncertainties for the liquid nitrogen to that for the melamine (C 3 H 6 N 6 ) widely used was improved by a factor of 2 above 2.2 MeV and a factor of 3 - 6 below 2.2 MeV. It has been shown that the liquid nitrogen target is useful for reduction of the 2.2 MeV γ-ray from the 1 H(n,γ) 2 H reaction and improvement of statistics. (author)

Kharkov X-ray Generator Based On Compton Scattering

International Nuclear Information System (INIS)

Shcherbakov, A.; Zelinsky, A.; Mytsykov, A.; Gladkikh, P.; Karnaukhov, I.; Lapshin, V.; Telegin, Y.; Androsov, V.; Bulyak, E.; Botman, J.I.M.; Tatchyn, R.; Lebedev, A.

2004-01-01

Nowadays X-ray sources based on storage rings with low beam energy and Compton scattering of intense laser beams are under development in several laboratories. An international cooperative project of an advanced X-ray source of this type at the Kharkov Institute of Physics and Technology (KIPT) is described. The status of the project is reviewed. The design lattice of the storage ring and calculated X-ray beam parameters are presented. The results of numerical simulation carried out for proposed facility show a peak spectral X-ray intensity of about 1014 can be produced

Investigation of plasma dynamics and x-ray emission in'ATON'plasma focus

International Nuclear Information System (INIS)

Soliman, H.M.; Masoud, M.M.

1995-01-01

The experimental studies on 20 kJ 'Aton' plasma focus device are presented in this paper. The plasma sheath structure has been investigated by means of the measurements of the axial and azimuthal magnetic fields along the coaxial electrodes. The operating gas was hydrogen with pressures in the range of 0.62 torr to 6 torr. The intensity of visible radiation emitted by the plasma sheath was measured as a function of axial distances along the coaxial electrodes. The results showed that the visible radiation intensity is increased with axial distances until a position near the muzzle, then it decreased and has a minimum value at the coaxial electrode muzzle. The main parameters contributing to the behavior of the distribution are the plasma sheath density and the impurities from the eroded materials of the discharge electrodes. An x-ray pulse has been detected along the coaxial electrodes and extended up to the expansion chamber. At a distance near the muzzle two x-ray pulses have been detected, the second one has intensity relative to the first one with time lag of 11μs. 8 fig

Modern X-ray spectroscopy 3. X-ray fluorescence holography

International Nuclear Information System (INIS)

Hayashi, Kouichi

2008-01-01

X-ray fluorescence holography (XFH) provides three dimensional atomic images around specified elements. The XFH uses atoms as a wave source or monitor of interference field within a crystal sample, and therefore it can record both intensity and phase of scattered X-rays. Its current performance makes it possible to apply to ultra thin film, impurity and quasicrystal. In this article, I show the theory including solutions for twin image problem, advanced measuring system, data processing for reconstruction of the atomic images and for obtaining accurate atomic positions, applications using resonant X-ray scattering and X-ray excited optical luminescence, and an example of XFH result on the local structure around copper in silicon steal. (author)

A tunable x-ray microprobe using synchrotron radiation

International Nuclear Information System (INIS)

Wu, Y.; Thompson, A.C.; Underwood, J.H.; Giauque, R.D.; Chapman, K.; Rivers, M.L.; Jones, K.W.

1989-08-01

We describe an x-ray microprobe using multilayer mirrors. Previously, we had demonstrated a Kirkpatrick-Baez type focusing system working at both 8 and 10 keV and successfully applied it to a variety of applications, including the determination of elemental contents in fluid inclusions. In this paper, we show that the usable excitation energy for this microprobe is not restricted to between 8 and 10 keV, and furthermore, it can be simply tuned in operation. A 10-keV x-ray fluorescence microprobe can be used to measure the concentration of the elements form potassium (Z = 19) to zinc (Z = 30) using K x-ray lines, and from cadmium (Z = 48) to erbium (Z = 68) using L x-ray lines. There are a number of geologically important elements in the gap between gallium (Z = 31) and silver(Z = 47) and also with Z > 68. In order to cover this range, a higher excitation energy is required. On the other hand, for samples that contain major elements with absorption edges lower than the excitation energy, it would be hard to detect other mirror elements because of the strong signal from the major elements and the background they produce. In this case, a tunable x-ray source can be used to avoid the excitation of the major elements. We demonstrate that, with the existing setup, it is possible to tune the excitation energy from 6 keV to 14 keV, in this range, the intensity does not decrease by more than one order of magnitude. As an illustration, a geological sample was examined by using two different excitation energy range as well as the possibility of improving the intensity. 11 refs., 5 figs

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

Science.gov (United States)

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

2018-01-01

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

Bone repair of the periapical lesions treated or not with low intensity laser (λ = 904 nm).(An X-ray study in human)

International Nuclear Information System (INIS)

Sousa, Gerdal Roberto de

2001-01-01

The purpose of this study was to evaluate the influence of low intensity laser on the bone repair over periapical lesions of dental elements. Fifteen patients with a total of eighteen periapical lesions were selected and divided into two groups. Lesions of the control group were submitted to endodontic treatment and/or periapical surgery and the lesions of the experimental laser group, were submitted to the same procedures of the first group but also irradiated by low intensity laser. It was used a 904 nm wavelength laser GaAs, employing 11 mW of power delivered by a fiber optic system, irradiation continuos and contact mode, using a fluency of 9 J/cm 2 . The mentioned treatment was repeated for 10 sessions with intervals of 72 hours between each session. Bone repair was evaluated through lesion measurements, which were accessed from the X ray pictures using a time and then, were also statistically analyzed. Results showed a significant difference between lased and control groups (p<0,10), emphasizing that for the laser group presented a significant reduction of the lesions area, confirmed by X ray. (author)

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)

Decreased waterborne pathogenic bacteria in an urban aquifer related to intense shallow geothermal exploitation.

Science.gov (United States)

García-Gil, Alejandro; Gasco-Cavero, Samanta; Garrido, Eduardo; Mejías, Miguel; Epting, Jannis; Navarro-Elipe, Mercedes; Alejandre, Carmen; Sevilla-Alcaine, Elena

2018-08-15

The implications of intensive use of shallow geothermal energy resources in shallow urban aquifers are still not known for waterborne pathogens relevant to human health. Firstly, we hypothesized that waterborne enteric pathogens would be relatively increased in heated groundwater plumes. To prove this, microbiological sampling of 31 piezometers covering the domain of an urban groundwater body affected by microbiological contamination and energetically exploited by 70 groundwater heat pump systems was performed. Mean differences of pathogenic bacteria contents between impacted and non-impacted monitoring points were assessed with a two-tailed independent Student's t-test or Mann-Whitney U and correlation coefficients were also calculated. Surprisingly, the results obtained revealed a significant and generalized decrease in waterborne pathogen contents in thermally impacted piezometers compared to that of non-impacted piezometers. This decrease is hypothesized to be caused by a heat shock to bacteria within the heat exchangers. The statistically significant negative correlations obtained between waterborne pathogen counts and temperature could be explained by the spatial distribution of the bacteria, finding that bacteria start to recover with increasing distance from the injection point. Also, different behavior groups fitting exponential regression models were found for the bacteria species studied, justified by the different presence and influence of several aquifer parameters and major, minor and trace elements studied, as well as the coexistence with other bacteria species. The results obtained from this work reinforce the concept of shallow geothermal resources as a clean energy source, as they could also provide the basis to control the pathogenic bacteria contents in groundwater bodies. Copyright © 2018 Elsevier B.V. All rights reserved.

Model of optical response of marine aerosols to Forbush decreases

DEFF Research Database (Denmark)

Bondo, Torsten; Enghoff, Martin Andreas Bødker; Svensmark, Henrik

2010-01-01

In order to elucidate the effect of galactic cosmic rays on cloud formation, we investigate the optical response of marine aerosols to Forbush decreases - abrupt decreases in galactic cosmic rays - by means of modeling. We vary the nucleation rate of new aerosols, in a sectional coagulation...

High-intensity x-ray holography: an approach to high-resolution snapshot imaging of biological specimens

International Nuclear Information System (INIS)

Solem, J.C.

1982-08-01

The crucial physical and technological issues pertaining to the holographic imaging of biological structures with a short-pulse, high-intensity, high-quantum-energy laser were examined. The limitations of x-ray optics are discussed. Alternative holographic techniques were considered, and it was concluded that far-field Fresnel transform holography (Fraunhofer holography) using a photoresist recording surface is most tractable with near term technology. The hydrodynamic expansion of inhomogeneities within the specimen is discussed. It is shown that expansion is the major source of image blurring. Analytic expressions were derived for the explosion of protein concentrations in an x-ray transparent cytoplasm, compared with numerical calculations, and corrections derived to account for the competitive transport processes by which these inhomogeneities lose energy. It is concluded that for the near term Fresnel transform holography, particularly, far-field or Fraunhofer holography, is more practical than Fourier transform holography. Of the alternative fine grain recording media for use with Fresnel transform holography, a photo-resist is most attractive. For best resolution, exposure times must be limited to a few picoseconds, and this calls for investigation of mechanisms to shutter the laser or gate the recording surface. The best contrast ratio between the nitrogen-bearing polymers (protein and the nucleic acids) and water is between the K-edges of oxygen and nitrogen

High-intensity x-ray holography: an approach to high-resolution snapshot imaging of biological specimens

Energy Technology Data Exchange (ETDEWEB)

Solem, J.C.

1982-08-01

The crucial physical and technological issues pertaining to the holographic imaging of biological structures with a short-pulse, high-intensity, high-quantum-energy laser were examined. The limitations of x-ray optics are discussed. Alternative holographic techniques were considered, and it was concluded that far-field Fresnel transform holography (Fraunhofer holography) using a photoresist recording surface is most tractable with near term technology. The hydrodynamic expansion of inhomogeneities within the specimen is discussed. It is shown that expansion is the major source of image blurring. Analytic expressions were derived for the explosion of protein concentrations in an x-ray transparent cytoplasm, compared with numerical calculations, and corrections derived to account for the competitive transport processes by which these inhomogeneities lose energy. It is concluded that for the near term Fresnel transform holography, particularly, far-field or Fraunhofer holography, is more practical than Fourier transform holography. Of the alternative fine grain recording media for use with Fresnel transform holography, a photo-resist is most attractive. For best resolution, exposure times must be limited to a few picoseconds, and this calls for investigation of mechanisms to shutter the laser or gate the recording surface. The best contrast ratio between the nitrogen-bearing polymers (protein and the nucleic acids) and water is between the K-edges of oxygen and nitrogen.

Soft x-ray emission from gamma-ray bursts observed with ginga

International Nuclear Information System (INIS)

Yoshida, Atsumasa; Murakami, Toshio; Itoh, Masayuki

1989-01-01

The soft X-ray emission of gamma-ray bursts below 10 keV provides information about size, location, and emission mechanism. The Gamma-ray Burst Detector (GBD) on board Ginga, which consists of a proportional counter and a scintillation detector, covers an energy range down to 1.5 keV with 63 cm 2 effective area. In several of the observed gamma-ray bursts, the intensity of the soft X-ray emission showed a longer decay time of 50 to 100s after the higher energy gamma-ray emission had ended. Although we cannot rule out other models, such as bremsstrahlung and thermal cyclotron types, due to poor statistics, the soft X-ray spectra are consistent with a blackbody of 1 to 2 keV in the late phase of the gamma-ray bursts. This enables us to estimate the size of the blackbody responsible for the X-ray emission. (author)

Intensity interferometry at the X13A undulator beamline

International Nuclear Information System (INIS)

Gluskin, E.; McNulty, I.; Yang, L.; Randall, K.J.; Johnson, E.D.

1993-01-01

We are constructing a soft x-ray intensity interferometer and an undulator based beamline to demonstrate intensity interferometry in the x-ray region. The 10-period soft x-ray undulator at the NSLS provides the necessary coherent flux; the X13A beamline is designed to preserve the spatial coherence of the bright x-ray beam and provide sufficient temporal coherence using a horizontally deflecting spherical grating monochromator. Using the interferometer, which consists of an array of small slits, a wedge-shaped beamsplitter and two fast microchannel plate detectors, we expect to measure the spatial coherence of the undulator beam and therefore the size of the source in the vertical plane. Details of the bean-dine design and the interferometer experiment are discussed

SLAC/DESY International Workshop on Interactions of Intense Sub-Picosecond X-Rays with Matter, Stanford, CA, January 23-24, 1997

International Nuclear Information System (INIS)

Tatchyn, Roman

1998-01-01

This is the proceedings volume of the 1997 SLAC/DESY International Workshop on Interactions of Intense Sub-picosecond X-Ray Pulses with Matter. The workshop theme evolved out of design and R and D studies, undertaken at SLAC, DESY, and elsewhere [1,2], of the new class of linac-driven X-Ray Free Electron Lasers (XRFELs) operating with photocathode-based, low-emittance electron beams in the Self-Amplified Spontaneous Emission (SASE) regime [3]. It can be noted that, following the conclusion of the workshop, funded design study reports on R and D facilities based on these novel sources have been completed and published by both laboratories [4,5]. Topical significance was imparted to the workshop agenda by a series of prior workshops organized to explore scientific and technological applications of linac driven XRFELs [6,7,8,9]. These served to highlight underlying concerns regarding the potential loading effects of the highly intense radiation pulses from this new class of light source on the instrumentation, samples, and experimental phenomena being considered. The primary objectives of the workshop were: (a) to provide tutorial overviews of existing theoretical, numerical, and experimental techniques in the study of interactions of intense, ultra-short radiation pulses with matter, and of their applicability to the parameter regimes of the SLAC and DESY XRFELs; (b) to discuss practical optics and instrumentation issues related to peak and average power density loading; (c) to identify and explore novel concepts and design approaches, with an emphasis on optical instrumentation and experimental physics; (d) to formulate independent or collaborative R and D programs and activities in the areas of theory, numerical simulation, and experimental physics relevant to the linac-driven XRFEL parameter regime

Equipment for x- and gamma ray radiography

International Nuclear Information System (INIS)

Abd Nasir Ibrahim; Azali Muhammad; Ab Razak Hamzah; Abd Aziz Mohamed; Mohammad Pauzi Ismail

2004-01-01

The following topics related to the equipment for x - and gamma ray radiography are discussed in this chapter. The topics are x-ray source for Industrial Radiography: properties of x-ray, generation of x-ray, mechanism of x-ray production, x-ray equipment, power supply, distribution of x-ray intensity along the tube: gamma ray source for Industrial Radiography: properties of gamma rays, gamma ray sources, gamma ray projectors on cameras, source changing. Care of Radiographic Equipments: Merits and Demerits of x and Gamma Rays

Origin of the cosmic x-ray background

International Nuclear Information System (INIS)

Margon, B.

1983-01-01

Since 1962, it has been known that every part of the sky emits a uniform glow of x-rays. After two decades of intense study the origin of this diffuse x-ray background is still a subject of controversy. The near perfect isotropy of the x-ray background is clearly a vital clue to its origin. A second clue to the origin of the x-ray background arises from the fact that it is x-radiation tha is generated, rather than some longer wavelength radiation. Two hypotheses of the origin of this x-ray background are discussed. One hypothesis is that the x-ray background can be attributed to bremsstrahlung from a hot intergalactic medium. The second hypothesis is that the x-ray background originates from a large number of quasars. Because there is no estimate independent of the intensity of the x-ray background of how much hot intergalactic medium exists (if any), there is a real possibility that both sources contribute to the observed x-rays. (SC)

Cone-beam x-ray luminescence computed tomography based on x-ray absorption dosage

Science.gov (United States)

Liu, Tianshuai; Rong, Junyan; Gao, Peng; Zhang, Wenli; Liu, Wenlei; Zhang, Yuanke; Lu, Hongbing

2018-02-01

With the advances of x-ray excitable nanophosphors, x-ray luminescence computed tomography (XLCT) has become a promising hybrid imaging modality. In particular, a cone-beam XLCT (CB-XLCT) system has demonstrated its potential in in vivo imaging with the advantage of fast imaging speed over other XLCT systems. Currently, the imaging models of most XLCT systems assume that nanophosphors emit light based on the intensity distribution of x-ray within the object, not completely reflecting the nature of the x-ray excitation process. To improve the imaging quality of CB-XLCT, an imaging model that adopts an excitation model of nanophosphors based on x-ray absorption dosage is proposed in this study. To solve the ill-posed inverse problem, a reconstruction algorithm that combines the adaptive Tikhonov regularization method with the imaging model is implemented for CB-XLCT reconstruction. Numerical simulations and phantom experiments indicate that compared with the traditional forward model based on x-ray intensity, the proposed dose-based model could improve the image quality of CB-XLCT significantly in terms of target shape, localization accuracy, and image contrast. In addition, the proposed model behaves better in distinguishing closer targets, demonstrating its advantage in improving spatial resolution.

Development of confocal micro X-ray fluorescence instrument using two X-ray beams

International Nuclear Information System (INIS)

Tsuji, Kouichi; Nakano, Kazuhiko; Ding Xunliang

2007-01-01

A new confocal micro X-ray fluorescence instrument was developed. This instrument has two independent micro X-ray tubes with Mo targets. A full polycapillary X-ray lens was attached to each X-ray tube. Another half polycapillary lens was attached to a silicon drift X-ray detector (SDD). The focal spots of the three lenses were adjusted to a common position. The effects of the excitation of two X-ray beams were investigated. The instrument enabled highly sensitive three-dimensional X-ray fluorescence analysis. We confirmed that the X-ray fluorescence intensity from the sample increased by applying the two independent X-ray tubes in confocal configuration. Elemental depth profiling of black wheat was demonstrated with the result that each element in the surface coat of a wheat grain showed unique distribution

X-ray filtration apparatus

International Nuclear Information System (INIS)

Thompson, G.

1992-01-01

This invention relates to an X-ray shielding support device. In spite of considerable development in X-ray taking techniques, a need still exists for effective shielding, inter alia, to compensate for variations in the thickness, density and the absorption properties of the object being studied. By appropriate shielding, the X-ray image produced is of sufficient detail, contrast and intensity over its entire area to constitute a useful diagnostic aid. It is also desirable to subject the patient to the smallest possible X-ray dosage. 4 figs

Crossover and valence band Kβ X-rays of chromium oxides

International Nuclear Information System (INIS)

Fazinic, Stjepko; Mandic, Luka; Kavcic, Matjaz; Bozicevic, Iva

2011-01-01

Kβ X-ray spectra of chromium metal and selected chromium oxides were measured twice using medium resolution flat crystal spectrometer and high resolution spectrometer employing Johansson geometry after excitation with 2 MeV proton beams. The positions and intensities of crossover (Kβ'') and valence (Kβ 2,5 ) band X-rays relative to the primary Kβ X-ray components were extracted in a consistent way. The results were compared with the existing data obtained by proton and photon induced ionization mechanisms and theoretical predictions. The obtained results in peak relative positions and intensities were analyzed in order to study dependence on the chromium oxidation states and chromium-oxygen bond lengths in selected chromium oxides. Our results obtained by both spectrometers confirm that the linear trend observed for the valence peak relative energy shift as a function of chromium oxidation number does not depend on the experimental resolution. Experimental results for normalized intensities (i.e. relative intensities divided with the number of chromium-oxygen pairs) of crossover and valence band X-rays obtained by both spectrometers are in very good agreement, and follow exponential relationship with the average Cr-O bond lengths in corresponding chromium oxides. The observed trends in crossover and valence X-rays normalized intensities could be used to measure the average chromium-oxygen bond length in various chromium oxides, with the sum of both crossover and valence X-ray normalized intensities being the most sensitive measure.

Supergiant Fast X-ray Transients with Swift: spectroscopic and temporal properties

OpenAIRE

Romano, P.; Mangano, V.; Ducci, L.; Esposito, P.; Farinelli, R.; Ceccobello, C.; Vercellone, S.; Burrows, D. N.; Kennea, J. A.; Krimm, H. A.; Gehrels, N.

2012-01-01

Supergiant fast X-ray transients (SFXTs) are a class of high-mass X-ray binaries with possible counterparts in the high energy gamma rays. The Swift SFXT Project has conducted a systematic investigation of the properties of SFTXs on timescales ranging from minutes to years and in several intensity states (from bright flares, to intermediate intensity states, and down to almost quiescence). We also performed broad-band spectroscopy of outbursts, and intensity-selected spectroscopy outside of o...

X-ray detector array

International Nuclear Information System (INIS)

Houston, J.M.

1980-01-01

The object of the invention (an ionization chamber X-ray detector array for use with high speed computerised tomographic imaging apparatus) is to reduce the time required to produce a tomographic image. The detector array described determines the distribution of X-ray intensities in one or more flat, coplanar X-ray beams. It comprises three flat anode sheets parallel to the X-ray beam, a plurality of rod-like cathodes between the anodes, a detector gas between the electrodes and a means for applying a potential between the electrodes. Each of the X-ray sources is collimated to give a narrow, planar section of X-ray photons. Sets of X-ray sources in the array are pulsed simultaneously to obtain X-ray transmission data for tomographic image reconstruction. (U.K.)

An experimental study on MRI signal intensity vs concentration of water-soluble contrast media

International Nuclear Information System (INIS)

Lee, Ghi Jai; Han, Chang Yul; Chang, Kee Hyun; Han, Moon Hee; Han, Man Chung

1991-01-01

There has been only one report that water-soluble contrast media containing iodine and used in conventional X -ray radiography reduce T1-and T2-relaxation times. We evaluated the relationship between signal intensity (relative signal intensity to normal saline) and T2-relaxation time of MRI and the concentration of 3 water-soluble contrast media [meglumine ioxithalamate (Telebrix 30), iopromide (Ultravist 300), iotrolan (Isovist 300)] through the phantom study, using both 2.0T and 0.5T MR units. We found that the signal intensity increased significantly on the T1-weighted images as the concentration of contrast media increased. The degree of the increase was larger on 0.5T MR than on 2.0T MR. The signal intensity on proton density image showed no significant difference at various concentrations. However, there were significant decreases of both signal intensity on the T2-weighted images and T2-relaxation time as the concentration of contrast media increased, which was more prominent on 2.0T MR than 0.5T MR. Between the contrast media of the same concentration, there was no significant difference in signal intensity and T2-relaxation time

X pinch a point x-ray source

International Nuclear Information System (INIS)

Garg, A.B.; Rout, R.K.; Shyam, A.; Srinivasan, M.

1993-01-01

X ray emission from an X pinch, a point x-ray source has been studied using a pin-hole camera by a 30 kV, 7.2 μ F capacitor bank. The wires of different material like W, Mo, Cu, S.S.(stainless steel) and Ti were used. Molybdenum pinch gives the most intense x-rays and stainless steel gives the minimum intensity x-rays for same bank energy (∼ 3.2 kJ). Point x-ray source of size (≤ 0.5 mm) was observed using pin hole camera. The size of the source is limited by the size of the pin hole camera. The peak current in the load is approximately 150 kA. The point x-ray source could be useful in many fields like micro lithography, medicine and to study the basic physics of high Z plasmas. (author). 4 refs., 3 figs

Time-resolved x-ray diffraction from frog skeletal muscle during an isotonic twitch under a small load

International Nuclear Information System (INIS)

Sugi, Haruo; Amemiya, Yoshiyuki; Hashizume, Hiroo.

1978-01-01

A time-resolved x-ray diffraction technique was used to study the time course of change in the intensity ratio Isub(1,0)/Isub(1,1) during isotonic twitch (initial sarcomere, 2.4 μm) under a small load and to determine the kinetic properties of the crossbridges responsible for muscle contraction. Isotonic twitches in four other preparations with an initial sarcomere of 2.4 μm and in two with an initial sarcomere of 2.3 μm and 2.2 μm, respectively, were examined. In each case, the intensity ratio started to decrease at stimulation, reached a minimum value of 0.8 - 1.0 within the first 20 - 30% of the shortening phase, and maintained this value until the beginning of the relaxation phase. Gradual recovery of the intensity ratio to the resting value was seen during the relaxation phase. During the recovery phase, the intensity ratio appeared to exhibit oscillatory changes. Though the extent of shortening was reduced by about 30% at the end of each experiment, the duration of the shortening phase remained almost unchanged in all the preparations examined. The time course of change in the intensity ratio was also examined during an isometric twitch in four preparations (sarcomere, 2.4 μm) with the tibial end connected to a strain gauge. The extent of internal shortening of muscle fibres against the tendons and the recording system during an isometric twitch or a tetanus at low temperatures was estimated. The intensity ratio decreased to a minimum value of 0.5 - 0.6 during the rising phase of isometric tension and started to return to the resting value after the beginning of relaxation. In both isotonic and isometric twitches, a decrease in the intensity ratio resulted from both a decrease in the 1,0 intensity and an increase in the 1,1 intensity. (J.P.N.)

A phenomenological study of the long-term cosmic ray modulation, 850-1958 AD

Science.gov (United States)

McCracken, K. G.; McDonald, F. B.; Beer, J.; Raisbeck, G.; Yiou, F.

2004-12-01

limit at those times. The 10Be data exhibit a previously unrecognized feature, which we have named "the precipitous decrease," in which the 1-2 GeV/nucleon intensity decreased by ˜40-45% between 1700 and 1739 corresponding to Δϕ > 500 MV, at a time of low but increasing solar activity. A lower cosmic ray intensity than that attained in 1739 was not observed again until after 1950, at a time of high solar activity. These features and the large 11-year modulation events during the Spoerer and Maunder minima indicate that the long-term variations in the GCR intensity are poorly related to sunspot number during epochs of low solar activity. It is shown that there is better agreement between the variations in the 10Be data, and the changes in the open solar magnetic flux predicted by the [2002] and [2002] models based on historic sunspot numbers. In particular, they both exhibit characteristics consistent with the precipitous decrease in the 10Be data, although the amplitudes are smaller than implied by the 10Be data.

X-ray beam size measurements on the Advanced Test Accelerator

International Nuclear Information System (INIS)

Struve, K.W.; Chambers, F.W.; Lauer, E.J.; Slaughter, D.R.

1986-01-01

The electron beam size has been determined on the Advanced Test Accelerator (ATA) by intercepting the beam with a target and measuring the resulting x-ray intensity as a function of time as the target is moved through the beam. Several types of targets have been used. One is a tantalum rod which extends completely across the drift chamber. Another is a tungsten powder filled carbon crucible. Both of these probes are moved from shot to shot so that the x-ray signal intensity varies with probe position. A third is a larger tantalum disk which is inserted on beam axis to allow determining beam size on a one shot basis. The x-ray signals are detected with an MCP photomultiplier tube located at 90 0 to the beamline. It is sufficiently shielded to reject background x-rays and neutrons. The signals were digitized, recorded and later unfolded to produce plots of x-ray intensity versus probe position for several times during the pulse. The presumption that the x-ray intensity is proportional to beam current density is checked computationally. Details of the probe construction and PMT shielding, as well as sample measurements are given

Generation of laser Compton gamma-rays using Compact ERL

International Nuclear Information System (INIS)

Shizuma, Toshiyuki; Hajima, Ryoichi; Nagai, Ryoji; Hayakawa, Takehito; Mori, Michiaki; Seya, Michio

2015-01-01

Nondestructive isotope-specific assay system using nuclear resonance fluorescence has been developed at JAEA. In this system, intense, mono-energetic laser Compton scattering (LCS) gamma-rays are generated by combining an energy recovery linac (ERL) and laser enhancement cavity. As technical development for such an intense gamma-ray source, we demonstrated generation of LCS gamma-rays using Compact ERL (supported by the Ministry of Education, Culture, Sports, Science and Technology) developed in collaboration with KEK. We also measured X-ray fluorescence for elements near iron region by using mono-energetic LCS gamma-rays. In this presentation, we will show results of the experiment and future plan. (author)

Simulation of intense short-pulse laser-plasma interaction

International Nuclear Information System (INIS)

Yamagiwa, Mitsuru

2000-01-01

We have completed the massive parallelization of a 2-dimensional giga-particle code and have achieved a 530-fold acceleration rate with 512 processing elements (PE's). Using this we have implemented a simulation of the interaction of a solid thin film and a high intensity laser and have discovered a phenomenon in which high quality short pulses from the far ultraviolet to soft X-rays are generated at the back surface of the thin layer. We have also introduced the atomic process database code (Hullac) and have the possibility for high precision simulations of X-ray laser radiation. With respect to laser acceleration we have the possibility to quantitatively evaluate relativistic self-focusing assumed to occur in higher intensity fields. Ion acceleration from a solid target and an underdense plasma irradiated by an intense and an ultra intense laser, respectively, has also been studied by particle-in-cell (PIC) simulations. (author)

Miniaturized High-Speed Modulated X-Ray Source

Science.gov (United States)

Gendreau, Keith C. (Inventor); Arzoumanian, Zaven (Inventor); Kenyon, Steven J. (Inventor); Spartana, Nick Salvatore (Inventor)

2015-01-01

A miniaturized high-speed modulated X-ray source (MXS) device and a method for rapidly and arbitrarily varying with time the output X-ray photon intensities and energies. The MXS device includes an ultraviolet emitter that emits ultraviolet light, a photocathode operably coupled to the ultraviolet light-emitting diode that emits electrons, an electron multiplier operably coupled to the photocathode that multiplies incident electrons, and an anode operably coupled to the electron multiplier that is configured to produce X-rays. The method for modulating MXS includes modulating an intensity of an ultraviolet emitter to emit ultraviolet light, generating electrons in response to the ultraviolet light, multiplying the electrons to become more electrons, and producing X-rays by an anode that includes a target material configured to produce X-rays in response to impact of the more electrons.

Tritium analysis of divertor tiles used in JET ITER-like wall campaigns by means of β-ray induced x-ray spectrometry

Science.gov (United States)

Hatano, Y.; Yumizuru, K.; Koivuranta, S.; Likonen, J.; Hara, M.; Matsuyama, M.; Masuzaki, S.; Tokitani, M.; Asakura, N.; Isobe, K.; Hayashi, T.; Baron-Wiechec, A.; Widdowson, A.; contributors, JET

2017-12-01

Energy spectra of β-ray induced x-rays from divertor tiles used in ITER-like wall campaigns of the Joint European Torus were measured to examine tritium (T) penetration into tungsten (W) layers. The penetration depth of T evaluated from the intensity ratio of W(Lα) x-rays to W(Mα) x-rays showed clear correlation with poloidal position; the penetration depth at the upper divertor region reached several micrometers, while that at the lower divertor region was less than 500 nm. The deep penetration at the upper part was ascribed to the implantation of high energy T produced by DD fusion reactions. The poloidal distribution of total x-ray intensity indicated higher T retention in the inboard side than the outboard side of the divertor region.

Observation of the thunderstorm-related ground cosmic ray flux variations by ARGO-YBJ

Science.gov (United States)

Bartoli, B.; Bernardini, P.; Bi, X. J.; Cao, Z.; Catalanotti, S.; Chen, S. Z.; Chen, T. L.; Cui, S. W.; Dai, B. Z.; D'Amone, A.; Danzengluobu; De Mitri, I.; D'Ettorre Piazzoli, B.; Di Girolamo, T.; Di Sciascio, G.; Feng, C. F.; Feng, Zhaoyang; Feng, Zhenyong; Gao, W.; Gou, Q. B.; Guo, Y. Q.; He, H. H.; Hu, Haibing; Hu, Hongbo; Iacovacci, M.; Iuppa, R.; Jia, H. Y.; Labaciren; Li, H. J.; Liu, C.; Liu, J.; Liu, M. Y.; Lu, H.; Ma, L. L.; Ma, X. H.; Mancarella, G.; Mari, S. M.; Marsella, G.; Mastroianni, S.; Montini, P.; Ning, C. C.; Perrone, L.; Pistilli, P.; Salvini, P.; Santonico, R.; Shen, P. R.; Sheng, X. D.; Shi, F.; Surdo, A.; Tan, Y. H.; Vallania, P.; Vernetto, S.; Vigorito, C.; Wang, H.; Wu, C. Y.; Wu, H. R.; Xue, L.; Yang, Q. Y.; Yang, X. C.; Yao, Z. G.; Yuan, A. F.; Zha, M.; Zhang, H. M.; Zhang, L.; Zhang, X. Y.; Zhang, Y.; Zhao, J.; Zhaxiciren; Zhaxisangzhu; Zhou, X. X.; Zhu, F. R.; Zhu, Q. Q.; D'Alessandro, F.; ARGO-YBJ Collaboration

2018-02-01

A correlation between the secondary cosmic ray flux and the near-earth electric field intensity, measured during thunderstorms, has been found by analyzing the data of the ARGO-YBJ experiment, a full coverage air shower array located at the Yangbajing Cosmic Ray Laboratory (4300 m a. s. l., Tibet, China). The counting rates of showers with different particle multiplicities (m =1 , 2, 3, and ≥4 ) have been found to be strongly dependent upon the intensity and polarity of the electric field measured during the course of 15 thunderstorms. In negative electric fields (i.e., accelerating negative charges downwards), the counting rates increase with increasing electric field strength. In positive fields, the rates decrease with field intensity until a certain value of the field EFmin (whose value depends on the event multiplicity), above which the rates begin increasing. By using Monte Carlo simulations, we found that this peculiar behavior can be well described by the presence of an electric field in a layer of thickness of a few hundred meters in the atmosphere above the detector, which accelerates/decelerates the secondary shower particles of opposite charge, modifying the number of particles with energy exceeding the detector threshold. These results, for the first time to our knowledge, give a consistent explanation for the origin of the variation of the electron/positron flux observed for decades by high altitude cosmic ray detectors during thunderstorms.

Rigidity spectrum of Forbush decrease calculated by neutron monitors data corrected and uncorrected for geomagnetic disturbances

International Nuclear Information System (INIS)

Alania, M V; Wawrzynczak, A; Sdobnov, V E; Kravtsova, M V

2013-01-01

Forbush decreases (Fd) of the galactic cosmic ray (GCR) intensity and geomagnetic storms are observed almost at the same time. Geomagnetic storm is a reason of significant disturbances of the magnetic cut off rigidity causing the distortion of the time profile of the Fd of the GCR intensity. We show some differences in the temporal changes of the rigidity spectra of Fd calculated by neutron monitors experimental data corrected and uncorrected for the changes of the geomagnetic cut off rigidity. Nevertheless, the general features of the temporal changes of the rigidity spectrum of Fd maintain as it was found in our previous investigations. Namely, at the beginning phase of Fd rigidity spectrum is relatively soft and gradually becomes hard up to reaching the minimum level of the GCR intensity; then the rigidity spectrum gradually becomes soft during the recovery phase of Fd. We also confirm that for the established temporal profiles of the rigidity spectrum of Fd a structural changes of the interplanetary magnetic field turbulence in the range of frequencies, 10 −-6 ÷10 −-5 Hz are responsible.

Computed radiography in neonatal intensive care

International Nuclear Information System (INIS)

Merlo, L.; Bighi, S.; Cervi, P.M.; Lupi, L.

1991-01-01

The Authors report their experience in the employment of a computerized digital radiographic system in Neonatal Intensive Care. The analog screen-film system is replaced by photosensitive imaging plates, scanned after X-ray exposure by a laser that releases the digital image, which can then be manipulated on computer work-stations. In a period of twelve months about 200 chest-abdomen X-ray examinations in Neonatal Intensive Care have been performed using this method with good technical and diagnostic results. The use of digital radiography in the neonatal area is of high interest: this system produces good quality images, there is a reduction in radiation dose and 'retakes', the system allows selective enhancement of different structures and their magnification. (orig.)

Observing Solvation Dynamics with Simultaneous Femtosecond X-ray Emission Spectroscopy and X-ray Scattering

DEFF Research Database (Denmark)

Haldrup, Kristoffer; Gawelda, Wojciech; Abela, Rafael

2016-01-01

and structural changes, and local solvent structural changes are desired. We have studied the intra- and intermolecular dynamics of a model chromophore, aqueous [Fe(bpy)3]2+, with complementary X-ray tools in a single experiment exploiting intense XFEL radiation as a probe. We monitored the ultrafast structural...... rearrangement of the solute with X-ray emission spectroscopy, thus establishing time zero for the ensuing X-ray diffuse scattering analysis. The simultaneously recorded X-ray diffuse scattering atterns reveal slower subpicosecond dynamics triggered by the intramolecular structural dynamics of the photoexcited...

Structural and X-Ray Photoelectron Spectroscopy Study of Al-Doped Zinc-Oxide Thin Films

Directory of Open Access Journals (Sweden)

Bong Ju Lee

2015-01-01

Full Text Available Al-doped zinc-oxide (AZO thin films were prepared by RF magnetron sputtering at different oxygen partial pressures and substrate temperatures. The charge-carrier concentrations in the films decreased from 1.69 × 1021 to 6.16 × 1017 cm−3 with increased gas flow rate from 7 to 21 sccm. The X-ray diffraction (XRD patterns show that the (002/(103 peak-intensity ratio decreased as the gas flow rate increased, which was related to the increase of AZO thin film disorder. X-ray photoelectron spectra (XPS of the O1s were decomposed into metal oxide component (peak A and the adsorbed molecular oxygen on thin films (peak B. The area ratio of XPS peaks (A/B was clearly related to the stoichiometry of AZO films; that is, the higher value of A/B showed the higher stoichiometric properties.

High-speed X-ray topography

International Nuclear Information System (INIS)

Eckers, W.; Oppolzer, H.

1977-01-01

The investigation of lattice defects in semiconductor crystals by conventional X-ray diffraction topography is very time-consuming. Exposure times can be reduced by using high-intensity X-rays and X-ray image intensifiers. The described system comprises a high-power rotating-anode X-ray tube, a remote-controlled X-ray topography camera, and a television system operating with an X-ray sensing VIDICON. System performance is demonstrated with reference to exploratory examples. The exposure time for photographic plates is reduced to 1/20 and for the X-ray TV system (resolution of the order of 30 μm) to 1/100 relative to that required when using a conventional topography system. (orig.) [de

Sensitometric curve of radiographic films by X-ray fluorescence

Energy Technology Data Exchange (ETDEWEB)

Gonçalves, E.A.S., E-mail: elicardo.goncalves@ifrj.edu.br [Instituto Federal do Rio de Janeiro (IFRJ), RJ (Brazil); Oliveira, D.F.; Anjos, M.J. dos; Oliveira, L.F. de [Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil); Lopes, R.T. [Coordenacao de Pos-Graduacao e Pesquisa de Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil)

2017-07-01

Radiographic film exposure is traditionally measured by the transmittance of a beam of light through the film. There are many mathematical and computational models to characterize the curve behavior and its properties, but almost none of them considers the limitations caused by the equipment used. As long as exposure in film increases, light intensity measured after the film decreases in a way that from a certain exposure, light could not be distinguished from any kind of noise. This work aims to propose x-ray fluorescence as a solution for better measure high exposed films and show how it could be modeled mathematically. (author)

X-ray topographic method of investigation of phase objects

International Nuclear Information System (INIS)

Levonyan, L.V.

2001-01-01

The intensity distribution of the monochromatized synchrotron radiation transmitting through the phase object and crystal-analyzer in Laue geometry is considered. It is shown that the local angular deviation of the incident radiation caused by the refraction on structural inhomogeneities of the object under investigation is directly transferred to the X-ray topographic image. In the absence of the phase object the latter consists of parallel straight fringes with a slowly decreasing period. The presence of the phase object changes the shape and period of fringes. The influence of the spatial and temporal coherence on the image is discussed. 5 refs

X-ray and. gamma. -ray sources: a comparison of their characteristics

Energy Technology Data Exchange (ETDEWEB)

Freund, A K [Institut Max von Laue - Paul Langevin, 38 - Grenoble (France)

1979-11-01

A comparison of the various source characteristics, in particular the available fluxes of radiation in the X-ray/..gamma..-ray region from (1) high power rotary anode X-ray generators, (2) radioactive ..gamma..-ray sources and (3) high energy electron storage rings is presented. Some of the specific characteristics and possible applications of synchrotron radiation as a source are discussed in detail, together with problems associated with the monochromatization of the continuous radiation in the X-ray/..gamma..-ray region. The new high energy machines PEP at Stanford, the 8 GeV storage ring CESR at Cornell and the PETRA storage ring in Hamburg, which will soon come into operation provide a spectrum of high intensity radiation reaching well above h..gamma..sub(photon)=100 keV. The possibilities of using ondulators (wigglers), and laser-electron scattering for constructing high repetition rate tunable ..gamma..-ray sources are also discussed. Finally the potentials of using the powerful spontaneous emission of ..gamma..-quanta by relativistic channeled particles are mentioned.

Effect of anti-sprouting gamma-ray doses on enzymatic fromation of flavour odor compounds in onion (Allium Cipa L)

International Nuclear Information System (INIS)

El-Sayed, S.A.; El-Waziri, S.M.

1977-01-01

Cysteine sulfoxide lyase activity, the development of lacrimatory factor and intensity of pungent flavour had been decreased, statistically, with increasing anti-sprouting gamma-ray dose and storage period after irradiation. Inactivation of lyase caused by 5 and 10 krad was perfectly recovered by the storage. The lyase activity was reactivated to unirradiated level at 4-5 months storage, respectively, under room temperature (20-25 C and 85-75%R.H.). 15kr inhibited the enzyme activity and could not be completely recovered and the characteristic flavour as well as the lacrimatory factor were drastically decreased by increasing storage time. Therefore, 10krad seems to be the maximum gamma ray dose proper for sprout-inhibition of Egyptian onions, Giza 6 variety, from technological point of view

Quality improvement in radiography in a neonatal intensive care unit

International Nuclear Information System (INIS)

Loovere, L.; Boyle, E.M.; Blatz, S.; Bowslaugh, M.; Kereliuk, M.; Paes, B.

2008-01-01

The primary objective of this study was to ensure that X-rays performed consistently adhere to established technological quality standards and are achieved without compromising patient care while minimizing exposure risks. The secondary objective was to evaluate whether educational sessions targeting areas deemed suboptimal would facilitate improvement. A retrospective, 1-week review of all neonatal X-rays and documentation of clinical information on X-ray requisitions (n = 132) was completed in a tertiary care neonatal intensive care unit (NICU), by a single observer. Standards for X-ray evaluation were defined a priori based on radiographic principles and essential documented medical information for correct interpretation. Targeted areas for improvement were identified and addressed through brief educational sessions and printed pamphlets. The review was repeated after recommendations were implemented. 1 month (n = 93) and 1 year (n = 76) later. Improvements were evident in both the completion of X-ray requisitions and image quality. In particular, there was a statistically significant improvement in requisition legibility (P = 0.019), completeness of the medical history (P < 0.001), reduction in X-ray rotation (P < 0.001), collimation to the specific area of interest (P <0.001), gonadal shielding (P < 0.001), and decrease in monitor leads or artifacts obscuring views (P < 0.001). These improvements were sustained both 1 month and 1 year following the educational sessions. A neonatal X-ray audit is a simple, effective way to evaluate radiographic technique and encourage provision of basic clinical information for diagnostic interpretation by radiologists and neonatologists. As well, structured, collaborative educational sessions between radiology and neonatology staff appear to be a successful and sustainable method to effect overall improvement. (author)

Feasibility study on X-ray source with pinhole imaging method

International Nuclear Information System (INIS)

Qiu Rui; Li Junli

2007-01-01

In order to verify the feasibility of study on X-ray source with pinhole imaging method, and optimize the design of X-ray pinhole imaging system, an X-ray pinhole imaging equipment was set up. The change of image due to the change of the position and intensity of X-ray source was estimated with mathematical method and validated with experiment. The results show that the change of the spot position and gray of the spot is linearly related with the change of the position and intensity of X-ray source, so it is feasible to study X-ray source with pinhole imaging method in this application. The results provide some references for the design of X-ray pinhole imaging system. (authors)

X-ray polarization measurements at relativistic laser intensities

International Nuclear Information System (INIS)

Beiersdorfer, P.; Shepherd, R.; Mancini, R.C.

2004-01-01

An effort has been started to measure the short pulse laser absorption and energy partition at relativistic laser intensities up to 10 21 W/cm 2 . Plasma polarization spectroscopy is expected to play an important role in determining fast electron generation and measuring the electron distribution function. (author)

Optimization of the x-ray monitoring angle for creating a correlation model between internal and external respiratory signals

Energy Technology Data Exchange (ETDEWEB)

Akimoto, Mami; Nakamura, Mitsuhiro; Mukumoto, Nobutaka; Yamada, Masahiro; Ueki, Nami; Matsuo, Yukinori; Sawada, Akira; Mizowaki, Takashi; Kokubo, Masaki; Hiraoka, Masahiro [Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto 606-8507 (Japan); Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan and Department of Radiological Technology, Faculty of Medical Science, Kyoto College of Medical Science, Nantan, Kyoto 622-0041 (Japan); Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto 606-8507 (Japan); Department of Radiation Oncology, Kobe City Medical Center General Hospital, Kobe, Hyogo 650-0047, Japan and Division of Radiation Oncology, Institute of Biomedical Research and Innovation, Kobe, Hyogo 650-0047 (Japan); Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto 606-8507 (Japan)

2012-10-15

interfractional variations in the intensity ratio were examined from the optimal x-ray monitoring angle. Results: A negative strong correlation was observed between the WEPL (x) and the intensity ratio (y) (y= 6.57 exp[-0.0125x]+ 1, R=-0.88 [95% confidence interval: -0.85 to -0.90], p < 0.01). Our proposed method effectively avoided having the x-ray beam pass through high-density structures, although there were large interpatient variations in the optimal x-ray monitoring angle because of the geometric arrangement between the gold markers and the anatomical structures. The minimum intensity ratios that were estimated from the WEPLs at the optimal x-ray monitoring angle ranged from 1.43 to 2.48, which was an average of 1.27 times (range, 1.02-1.66) higher than the angles used for setup verification. The maximum intra- and interfractional decreases in the intensity ratio were 0.23 and 0.17, respectively. Conclusions: The authors demonstrated that the optimal x-ray monitoring angle for creating a 4D model can improve the visibility of gold markers.

Ultra-short wavelength x-ray system

Science.gov (United States)

Umstadter, Donald [Ann Arbor, MI; He, Fei [Ann Arbor, MI; Lau, Yue-Ying [Potomac, MD

2008-01-22

A method and apparatus to generate a beam of coherent light including x-rays or XUV by colliding a high-intensity laser pulse with an electron beam that is accelerated by a synchronized laser pulse. Applications include x-ray and EUV lithography, protein structural analysis, plasma diagnostics, x-ray diffraction, crack analysis, non-destructive testing, surface science and ultrafast science.

X-ray astronomy

International Nuclear Information System (INIS)

Culhane, J.L.; Sanford, P.W.

1981-01-01

X-ray astronomy has been established as a powerful means of observing matter in its most extreme form. The energy liberated by sources discovered in our Galaxy has confirmed that collapsed stars of great density, and with intense gravitational fields, can be studied by making observations in the X-ray part of the electromagnetic spectrum. The astronomical objects which emit detectable X-rays include our own Sun and extend to quasars at the edge of the Universe. This book describes the history, techniques and results obtained in the first twenty-five years of exploration. Space rockets and satellites are essential for carrying the instruments above the Earth's atmosphere where it becomes possible to view the X-rays from stars and nebulae. The subject is covered in chapters, entitled: the birth of X-ray astronomy; the nature of X-radiation; X-rays from the Sun; solar-flare X-rays; X-rays from beyond the solar system; supernovae and their remnants; X-rays from binary stars; white dwarfs and neutron stars; black holes; X-rays from galaxies and quasars; clusters of galaxies; the observatories of the future. (author)

Gamma-ray pulsars and Geminga

International Nuclear Information System (INIS)

Ruderman, M.; Halpern, J.P.; Chen, K.; Cheng, K.S.

1992-01-01

Observed properties of γ-ray pulsars are related to those of the accelerators which power their radiation. It is argued that the relatively slowly spinning Geminga is a strong γ-ray source only because its magnetic dipole is more inclined than that of the more rapidly spinning Vela. This would also account for special Geminga properties including 180 degrees subpulse separation, soft X-ray spectra and intensities, and suppression of radio emission

The digital flat-panel X-Ray detectors

International Nuclear Information System (INIS)

Risticj, S. Goran

2013-01-01

In a digital imaging system, the incident x-ray image must be sampled both in the spatial and intensity dimensions. In the spatial dimensions, samples are obtained as averages of the intensity over picture elements or pixels. In the intensity dimension, the signal is digitalized into one of a finite number of levels or bits. Two main types of digital flat-panel detectors are based on the direct conversion, which contains the photoconductor, and on indirect conversion, which contains phosphor. The basics of these detectors are given. Coupling traditional x-ray detection material such as photoconductors and phosphors with a large-area active-matrix readout structure forms the basis of flat panel x-ray images. Active matrix technology provides a new, highly efficient, real time method for electronically storing and measuring the product of the x-ray interaction stage whether the product is visible wavelength photons or electrical charges. The direct and indirect detectors, made as the active-matrix flat-panel detectors containing sensing/storage elements, switching elements (diodes or thin film transistors (TFTS)) and image processing module, are described. Strengths and limitations of stimulable phosphors are discussed. The main advantages and disadvantages of mentioned x-ray detectors are also analyzed. (Author)

Tolerance limits of X-ray image intensity

International Nuclear Information System (INIS)

Stargardt, A.; Juran, R.; Brandt, G.A.

1985-01-01

Evaluation of the tolerance limits of X-ray image density accepted by the radiologist shows that for different kinds of examinations, deviations of more than 50% from optimal density lead to images which cannot be used diagnostically. Within this range diagnostic accuracy shows a distinct maximum and diminishes to the limits by 20%. These figures are related to differences in the intensifying factor of screens, sensitivity of films, sensitometric parameters of film processing as well as the doses employed with automatic exposure control devices, measured in clinical conditions. Maximum permissible tolerance limits of the whole imaging system and of its constituents are discussed using the Gaussian law of error addition. (author)

Comparison of specular H-atomic-beam intensity and C+ secondary-ion yield at thermally activated decrease of a carbon layer on a Ni(110) surface

International Nuclear Information System (INIS)

Kaarmann, H.; Hoinkes, H.; Wilsch, H.

1983-01-01

The thermally activated disappearance of a carbon layer on a Ni(110) surface was investigated by the scattering of atomic hydrogen and by secondary-ion mass spectrometry. Decreasing C coverage at surface temperatures kept constant in each case at values between 650 and 750 K resulted in an exponential decrease of specular H-beam intensity as well as C + secondary-ion yield. This decrease in both cases fits first-order kinetics (presumable diffusion into the bulk) with an identical rate constant as a function of surface temperature and results finally in a preexponential frequency ν = 10/sup() 10plus-or-minus1/ s -1 and an activation energy E/sub A/ = 1.8 +- 0.2 eV

X-Ray Lasers 2016

CERN Document Server

Bulanov, Sergei; Daido, Hiroyuki; Kato, Yoshiaki

2018-01-01

These proceedings comprise a selection of invited and contributed papers presented at the 15th International Conference on X-Ray Lasers (ICXRL 2016), held at the Nara Kasugano International Forum, Japan, from May 22 to 27, 2016. This conference was part of an ongoing series dedicated to recent developments in the science and technology of x-ray lasers and other coherent x-ray sources with additional focus on supporting technologies, instrumentation and applications.   The book showcases recent advances in the generation of intense, coherent x-rays, the development of practical devices and their applications across a wide variety of fields. It also discusses emerging topics such as plasma-based x-ray lasers, 4th generation accelerator-based sources and higher harmonic generations, as well as other x-ray generation schemes.

The additional dose to radiosensitive organs caused by using under-collimated X-ray beams in neonatal intensive care radiography

International Nuclear Information System (INIS)

Datz, H.; Ben-Shlomo, A.; Margaliot, M.; Bader, D.; Sadetzki, S.; Juster-Reicher, A.; Marks, K.; Smolkin, T.; Zangen, S.

2008-01-01

Radiographic technique and exposure parameters were recorded in five Israeli Neonatal Intensive Care Units for chest, abdomen and both chest and abdomen X-ray examinations. Equivalent dose and effective dose values were calculated according to actual examination field size borders and proper technique field size recommendations using PCXMC, a PC-based Monte Carlo program. Exposure of larger than required body areas resulted in an increase of the organ doses by factors of up to 162 (testes), 162 (thyroid) and 8 (thyroid) for chest, abdomen and both chest and abdomen examinations, respectively. These exposures increased the average effective dose by factors of 2.0, 1.9 and 1.3 for the chest, abdomen and both chest and abdomen examinations, respectively. Differences in exposure parameters were found between the different neonatal intensive care units - tube voltage, current-time product and focal to skin distance differences up to 13, 44 and 22%, respectively. Reduction of at least 50% of neonate exposure is feasible and can be implemented using existing methodology without any additional costs. (authors)

Development of X-ray photoelectron microscope with a compact X-ray source generated by line-focused laser irradiation

International Nuclear Information System (INIS)

Yamaguchi, N.; Takahashi, Z.; Nishimura, Y.; Watanabe, K.; Okamoto, Y.; Sakata, A.; Azuma, H.; Hara, T.

2005-01-01

A laboratory-sized X-ray photoelectron microscope was constructed using a compact X-ray source produced by line-focused laser irradiation. The system is a scanning type photoelectron microscope where X-ray beam is micro-focused via Schwarzschild optics. A compact laser-plasma X-ray source has been developed with a YAG laser, a line-focus lens assembly, an Al tape-target driver and a debris prevention system. The 13.1 nm X-ray was delivered along line plasma whose length was 0.6 or 11 mm with higher intensity than that from a point-focused source. The Schwarzschild optics having the designed demagnification of 224, which was coated with Mo/Si multilayers for 13.1 nm X-ray, was set on the beamline 1 m distant from the source. The electron energy analyser was a spherical capacitor analyser with the photoelectron image detection system that was suited for detection of vast photoelectrons excited by an X-ray pulse of ns-order duration. The spatial resolution less than 5 μm has been confirmed from the variation of As 3d electron intensity along the position of the GaAs sample coated with a photo-resist test pattern

Study of caprine bones after moist and dry heat processes by X-ray diffraction

International Nuclear Information System (INIS)

Barbosa, Caroline M.; Azeredo, Soraia R.; Lopes, Ricardo T.; Souza, Sheila M.F.M de

2013-01-01

Bone tissue is a biological material composed of hydroxyapatite (HAp) and collagen matrix. The bone X-ray diffraction (XRD) pattern presents characteristics of the hydroxyapatite crystallography planes. This paper presents the characterization by X-ray diffraction of caprine bone powder pattern and the comparison of this pattern with moist or dry heat cooked bone patterns. The parameters chosen to characterize the X-ray diffraction peaks were: angular position (2θ), full width at half maximumt (FWHM), and relative intensity (I rel ). The X-ray diffraction patterns were obtained with a Shimadzu XRD-6000 diffractometer. The caprine bone XRD pattern revealed a significant correlation of several crystallographic parameters (lattice data) with hydroxyapatite. The profiles of the three bone types analyzed presented differences. The study showed as small angular displacement (decrease of the 2θ angle) of some peaks was observed after moist and dry heat cooking processes. The characterization of bone tissue aimed to contribute to future analysis in the field of archeology. (author)

Study of caprine bones after moist and dry heat processes by X-ray diffraction

Energy Technology Data Exchange (ETDEWEB)

Barbosa, Caroline M., E-mail: carolmattosb@yahoo.com.br [Instituto de Arqueologia Brasileira (IAB), Belford Roxo, RJ (Brazil); Azeredo, Soraia R.; Lopes, Ricardo T., E-mail: soraia@lin.ufrj.br [Coordenacao dos Programas de Pos-Graduacao em Engenharia (COPPE/LIN/UFRJ), Rio de Janeiro, RJ (Brazil). Laboratorio de Instrumentacao Nuclear; Souza, Sheila M.F.M de, E-mail: sferraz@ensp.fiocruz.br [Fundacao Oswaldo Cruz (ENSP/FIOCRUZ), Rio de Janeiro, RJ (Brazil). Escola Nacional de Saude Publica Sergio Arouca

2013-07-01

Bone tissue is a biological material composed of hydroxyapatite (HAp) and collagen matrix. The bone X-ray diffraction (XRD) pattern presents characteristics of the hydroxyapatite crystallography planes. This paper presents the characterization by X-ray diffraction of caprine bone powder pattern and the comparison of this pattern with moist or dry heat cooked bone patterns. The parameters chosen to characterize the X-ray diffraction peaks were: angular position (2θ), full width at half maximumt (FWHM), and relative intensity (I{sub rel}). The X-ray diffraction patterns were obtained with a Shimadzu XRD-6000 diffractometer. The caprine bone XRD pattern revealed a significant correlation of several crystallographic parameters (lattice data) with hydroxyapatite. The profiles of the three bone types analyzed presented differences. The study showed as small angular displacement (decrease of the 2θ angle) of some peaks was observed after moist and dry heat cooking processes. The characterization of bone tissue aimed to contribute to future analysis in the field of archeology. (author)

Characteristics of specifications of transportable inverter-type X-ray equipment

International Nuclear Information System (INIS)

Yamamoto, Keiichi; Miyazaki, Shigeru

2003-01-01

Our X-ray systems study group measured and examined the characteristics of four transportable inverter-type X-ray equipments. X-ray tube voltage and X-ray tube current were measured with the X-ray tube voltage and the X-ray tube current measurement terminals provided with the equipment. X-ray tube voltage, irradiation time, and dose were measured with a non-invasive X-ray tube voltage-measuring device, and X-ray output was measured by fluorescence meter. The items investigated were the reproducibility and linearity of X-ray output, error of pre-set X-ray tube voltage and X-ray tube current, and X-ray tube voltage ripple percentage. The waveforms of X-ray tube voltage, the X-ray tube current, and fluorescence intensity draw were analyzed using the oscilloscope gram and a personal computer. All of the equipment had a preset error of X-ray tube voltage and X-ray tube current that met Japanese Industrial Standards (JIS) standards. The X-ray tube voltage ripple percentage of each equipment conformed to the tendency to decrease when X-ray tube voltage increased. Although the X-ray output reproducibility of system A exceeded the JIS standard, the other systems were within the JIS standard. Equipment A required 40 ms for X-ray tube current to reach the target value, and there was some X-ray output loss because of a trough in X-ray tube current. Owing to the influence of the ripple in X-ray tube current, the strength of the fluorescence waveform rippled in equipments B and C. Waveform analysis could not be done by aliasing of the recording device in equipment D. The maximum X-ray tube current of transportable inverter-type X-ray equipment is as low as 10-20 mA, and the irradiation time of chest X-ray photography exceeds 0.1 sec. However, improvement of the radiophotographic technique is required for patients who cannot move their bodies or halt respiration. It is necessary to make the irradiation time of the equipments shorter for remote medical treatment. (author)

X-ray diagnostic in gas discharge

International Nuclear Information System (INIS)

Chen Suhe; Wang Dalun; Cui Gaoxian; Wang Mei; Fu Yibei; Zhang Xinwei; Zhang Wushou

1995-01-01

X rays were observed when the anomalous phenomenon in the metal loaded with deuterium studied by the gas-discharge method. Therefore the X-ray energy spectra were measured by the absorption method, the specific X-ray approach and the NaI scintillation counter, while X-ray intensity was estimated by using 7 Li thermoluminescent foils. The X-ray average energy measured by the absorption method is 27.6 +- 2.1 keV, which is fitted within the error extent to 26.0 +-2.4 keV monoenergetic X rays measured by the NaI scintillation counter

Observation of solar gamma-ray by Hinotori

International Nuclear Information System (INIS)

Yoshimori, Masato; Okudaira, Kiyoaki; Hirashima, Yo; Kondo, Ichiro.

1982-01-01

The solar gamma-ray emitted by solar flare was observed. The gamma-ray is the electromagnetic radiation with the energy more than 300 keV. The line gamma-ray intensity and the time profile were observed. The gamma-ray detector CsI (Tl) was loaded on Hinotori, and the observed gamma-ray was analyzed by a multi-channel analyzer. The observed line gamma-ray was the radiation from Fe-56 and Ne-20. The line gamma-ray from C-12 and O-16 was also seen. These gamma-ray is the direct evidence of the nuclear reaction on the sun. The observed spectrum suggested the existence of the lines from Mg-24 and Si-28. The intensity of the 2.22 MeV gamma-line was small. This fact showed that the origin of this line was different from other nuclear gamma-ray. Two kinds of hard X-ray bursts were detected. The one was impulsive burst, and the other was gradual burst. There was no time difference between the hard X-ray and the gamma-ray of the impulsive burst. The impulsive burst may be explained by the beam model. The delay of time profile in the high energy gamma-ray of the gradual burst was observed. This means that the time when accelerated electrons cause bremsstrahlung depends on the electron energy. The long trapping of electrons at the top of magnetic loop is suggested. (Kato, T.)

Synchrotron x-ray fluorescence and extended x-ray absorption fine structure analysis

International Nuclear Information System (INIS)

Chen, J.R.; Gordon, B.M.; Hanson, A.L.; Jones, K.W.; Kraner, H.W.; Chao, E.C.T.; Minkin, J.A.

1984-01-01

The advent of dedicated synchrotron radiation sources has led to a significant increase in activity in many areas of science dealing with the interaction of x-rays with matter. Synchrotron radiation provides intense, linearly polarized, naturally collimated, continuously tunable photon beams, which are used to determine not only the elemental composition of a complex, polyatomic, dilute material but also the chemical form of the elements with improved accuracy. Examples of the application of synchrotron radiation include experiments in synchrotron x-ray fluorescence (SXRF) analysis and extended x-ray absorption fine structure (EXAFS) analysis. New synchrotron radiation x-ray microprobes for elemental analysis in the parts per billion range are under construction at several laboratories. 76 references, 24 figures

Development on the muonic X-ray analysis for planetary materials

International Nuclear Information System (INIS)

Terada, Kentaro

2017-01-01

Three-dimensional nondestructive element analysis using muons artificially generated by bombarding carbon nuclei with high-energy protons has become realistic. This paper explained the principle of characteristic X-ray element analysis by means of negative muon beams. Next, as the experiments demonstrating the advantages of negative muon characteristic X-rays using the high-intensity proton accelerator facility (J-PARC MUSE), it explained the following experiments: (1) measurement of the depth profile of negative muon characteristic X-ray intensity of B, C, N, O using four-layer simulated samples, (2) negative muon characteristic X-ray analysis of carbonaceous chondrites meteorite (Murchison and Allende meteorite) samples, and (3) negative muon characteristic X-ray measurement of Murchison meteorite enclosed in a glass tube. It also introduced the negative muon characteristic X-ray analysis of carbonaceous chondrite meteorite sample, Jbilet Winselwan, at MuSIC (Muon Science Innovative muon beam channel) of the Research Center for Nuclear Physics of Osaka University. MuSIC increased the negative muon beam intensity by 50 times and introduced a double strip CdTe detector capable of X-ray imaging, aiming at the practical application of three-dimensional nondestructive element analysis. (A.O.)

Inflammatory process decrease by gallium-aluminium-arsenide (GaAlAs) low intensity laser irradiation on postoperative extraction of impacted lower third molar

International Nuclear Information System (INIS)

Atihe, Mauricio Martins

2002-01-01

This study aimed the observation of inflammatory process decrease by the use of GaAlAs Low Intensity Laser (λ=830 nm; 40 mW) irradiation. Five patients were selected and submitted to surgery of impacted lower third molars, both right and left sides at different occasions. On a first stage, a tooth of a random chosen side - right or left - was extracted by conventional surgery, without LILT. The inflammatory process was measured at postoperative on the first, third and seventh days. This side was then called 'control side'. After 21 days, period in which the inflammatory process of the first surgery was terminated, the other side surgery took place, this time using LILT (4 J at four spots) at postoperative, first and third days. As the previous surgery, the inflammatory process was also measured at postoperative on the first, third and seventh days. This side was called 'experimental or lased side'. The inflammatory process was evaluated by measuring its four characteristic signs: swelling, pain, color and temperature. It was clearly observed a decrease for swelling, pain and color on the lased side which presented significant inference and descriptive statistics. It can be concluded that GaAlAs Low Intensity Laser (λ=830 nm) can surely be used as an additional and important anti-inflammatory source on impacted lower third molar surgeries. (author)

Decreasing Temporal Lobe Dose With Five-Field Intensity-Modulated Radiotherapy for Treatment of Pituitary Macroadenomas

International Nuclear Information System (INIS)

Parhar, Preeti K.; Duckworth, Tamara; Shah, Parinda; DeWyngaert, J. Keith; Narayana, Ashwatha; Formenti, Silvia C.; Shah, Jinesh N.

2010-01-01

Purpose: To compare temporal lobe dose delivered by three pituitary macroadenoma irradiation techniques: three-field three-dimensional conformal radiotherapy (3D-CRT), three-field intensity-modulated radiotherapy (3F IMRT), and a proposed novel alternative of five-field IMRT (5F IMRT). Methods and Materials: Computed tomography-based external beam radiotherapy planning was performed for 15 pituitary macroadenoma patients treated at New York University between 2002 and 2007 using: 3D-CRT (two lateral, one midline superior anterior oblique [SAO] beams), 3F IMRT (same beam angles), and 5F IMRT (same beam angles with additional right SAO and left SAO beams). Prescription dose was 45 Gy. Target volumes were: gross tumor volume (GTV) = macroadenoma, clinical target volume (CTV) = GTV, and planning target volume = CTV + 0.5 cm. Structure contouring was performed by two radiation oncologists guided by an expert neuroradiologist. Results: Five-field IMRT yielded significantly decreased temporal lobe dose delivery compared with 3D-CRT and 3F IMRT. Temporal lobe sparing with 5F IMRT was most pronounced at intermediate doses: mean V25Gy (% of total temporal lobe volume receiving ≥25 Gy) of 13% vs. 28% vs. 29% for right temporal lobe and 14% vs. 29% vs. 30% for left temporal lobe for 5F IMRT, 3D-CRT, and 3F IMRT, respectively (p -7 for 5F IMRT vs. 3D-CRT and 5F IMRT vs. 3F IMRT). Five-field IMRT plans did not compromise target coverage, exceed normal tissue dose constraints, or increase estimated brain integral dose. Conclusions: Five-field IMRT irradiation technique results in a statistically significant decrease in the dose to the temporal lobes and may thus help prevent neurocognitive sequelae in irradiated pituitary macroadenoma patients.

Fast and robust ray casting algorithms for virtual X-ray imaging

International Nuclear Information System (INIS)

Freud, N.; Duvauchelle, P.; Letang, J.M.; Babot, D.

2006-01-01

Deterministic calculations based on ray casting techniques are known as a powerful alternative to the Monte Carlo approach to simulate X- or γ-ray imaging modalities (e.g. digital radiography and computed tomography), whenever computation time is a critical issue. One of the key components, from the viewpoint of computing resource expense, is the algorithm which determines the path length travelled by each ray through complex 3D objects. This issue has given rise to intensive research in the field of 3D rendering (in the visible light domain) during the last decades. The present work proposes algorithmic solutions adapted from state-of-the-art computer graphics to carry out ray casting in X-ray imaging configurations. This work provides an algorithmic basis to simulate direct transmission of X-rays, as well as scattering and secondary emission of radiation. Emphasis is laid on the speed and robustness issues. Computation times are given in a typical case of radiography simulation

Fast and robust ray casting algorithms for virtual X-ray imaging

Energy Technology Data Exchange (ETDEWEB)

Freud, N. [CNDRI, Laboratory of Nondestructive Testing Using Ionizing Radiations, INSA-Lyon Scientific and Technical University, Bat. Antoine de Saint-Exupery, 20, Avenue Albert Einstein, 69621 Villeurbanne Cedex (France)]. E-mail: Nicolas.Freud@insa-lyon.fr; Duvauchelle, P. [CNDRI, Laboratory of Nondestructive Testing Using Ionizing Radiations, INSA-Lyon Scientific and Technical University, Bat. Antoine de Saint-Exupery, 20, Avenue Albert Einstein, 69621 Villeurbanne Cedex (France); Letang, J.M. [CNDRI, Laboratory of Nondestructive Testing Using Ionizing Radiations, INSA-Lyon Scientific and Technical University, Bat. Antoine de Saint-Exupery, 20, Avenue Albert Einstein, 69621 Villeurbanne Cedex (France); Babot, D. [CNDRI, Laboratory of Nondestructive Testing Using Ionizing Radiations, INSA-Lyon Scientific and Technical University, Bat. Antoine de Saint-Exupery, 20, Avenue Albert Einstein, 69621 Villeurbanne Cedex (France)

2006-07-15

Deterministic calculations based on ray casting techniques are known as a powerful alternative to the Monte Carlo approach to simulate X- or {gamma}-ray imaging modalities (e.g. digital radiography and computed tomography), whenever computation time is a critical issue. One of the key components, from the viewpoint of computing resource expense, is the algorithm which determines the path length travelled by each ray through complex 3D objects. This issue has given rise to intensive research in the field of 3D rendering (in the visible light domain) during the last decades. The present work proposes algorithmic solutions adapted from state-of-the-art computer graphics to carry out ray casting in X-ray imaging configurations. This work provides an algorithmic basis to simulate direct transmission of X-rays, as well as scattering and secondary emission of radiation. Emphasis is laid on the speed and robustness issues. Computation times are given in a typical case of radiography simulation.

Single-shot beam-position monitor for x-ray free electron laser

Science.gov (United States)

Tono, Kensuke; Kudo, Togo; Yabashi, Makina; Tachibana, Takeshi; Feng, Yiping; Fritz, David; Hastings, Jerome; Ishikawa, Tetsuya

2011-02-01

We have developed an x-ray beam-position monitor for detecting the radiation properties of an x-ray free electron laser (FEL). It is composed of four PIN photodiodes that detect backscattered x-rays from a semitransparent diamond film placed in the beam path. The signal intensities from the photodiodes are used to compute the beam intensity and position. A proof-of-principle experiment at a synchrotron light source revealed that the error in the beam position is reduced to below 7 μm by using a nanocrystal diamond film prepared by plasma-enhanced chemical vapor deposition. Owing to high dose tolerance and transparency of the diamond film, the monitor is suitable for routine diagnostics of extremely intense x-ray pulses from the FEL.

X-ray spectroscopy of a thin foil plasma produced by a short-pulse high-intensity laser

International Nuclear Information System (INIS)

Audebert, P.; Nagels, V.; Geindre, J.P.; Dorchies, F.; Peyrusse, O.; Gary, S.; Girard, F.; Shepherd, R.; Gauthier, J.C.; Chenais-Popovics, C.

2003-01-01

High density and temperature plasmas have been generated by irradiating thin foils of various elements with a high-energy subpicosecond laser pulse. The X-ray emission duration was studied by time-resolved X-ray spectroscopy. Frequency domain interferometry provided a measurement of the hydrodynamic expansion of the back of the foil as a function of time. The effect of longitudinal temperature gradients, i.e., gradients perpendicular to the surface, were decreased using very thin foil targets. Additionally, radial gradients effects, i.e., gradients parallel to the surface, were limited by using a 50 μm pinhole on target. The Al, Se and Sm spectra, recorded in the range 7.7-8 Angst. using a conical crystal spectrometer coupled to an 800 fs resolution streak camera, lasted a few picoseconds. Sm spectra showed no spectral features in this wavelength range, providing a spectrally homogeneous backlighter for future experiments. The main features of the experimental time-resolved spectra have been well reproduced with one-dimensional hydrodynamic simulations of the free expansion of a plasma heated at a given initial temperature obtained from the expansion velocity of the rear critical surface of the plasma

Production of X-rays by inverse Compton effect

International Nuclear Information System (INIS)

Mainardi, R.T.

2005-01-01

X-rays and gamma rays of high energy values can be produced by the scattering of low energy photons with high energy electrons, being this a process controlled by the Compton scattering. If a laser beam is used, the x-ray beam inherits the properties of intensity, monochromaticity and collimation from the laser. In this work we analyze the generation of intense x-ray beams of energies between 10 and 100 KeV to be used in a wide range of applications where a high intensity and high degrees of monochromaticity and polarization are important properties to improve image reduce doses and improve radiation treatments. To this purpose we evaluated, using relativistic kinematics the scattered beam properties in terms of the scattering angle. This arrangement is being considered in several worldwide laboratories as an alternative to synchrotron radiation and is referred to as 'table top synchrotron radiation', since it cost of installation is orders of magnitude smaller than a 'synchrotron radiation source'. The radiation beam might exhibit non-linear properties in its interaction with matter, in a similar way as a laser beam and we will investigate how to calibrate and evaluate TLD dosemeters properties, both in low and high intensity fields either mono or polyenergetic in wide spectral energy ranges. (Author)

Cosmic gamma-ray background from dark matter annihilation

International Nuclear Information System (INIS)

Ando, Shin'ichiro

2007-01-01

High-energy photons from pair annihilation of dark matter particles contribute to the cosmic gamma-ray background (CGB) observed in a wide energy range. The precise shape of the energy spectrum of CGB depends on the nature of dark matter particles. In order to discriminate between the signals from dark matter annihilation and other astrophysical sources, however, the information from the energy spectrum of CGB may not be sufficient. We show that dark matter annihilation not only contributes to the mean CGB intensity, but also produces a characteristic anisotropy, which provides a powerful tool for testing the origins of the observed CGB. We show that the expected sensitivity of future gamma-ray detectors such as GLAST should allow us to measure the angular power spectrum of CGB anisotropy, if dark matter particles are supersymmetric neutralinos and they account for most of the observed mean intensity. As the intensity of photons from annihilation is proportional to the density squared, we show that the predicted shape of the angular power spectrum of gamma rays from dark matter annihilation is different from that due to other astrophysical sources such as blazars, whose intensity is linearly proportional to density. Therefore, the angular power spectrum of the CGB provides a 'smoking-gun' signature of gamma rays from dark matter annihilation

Z-pinches as intense x-ray sources for high energy density physics application

International Nuclear Information System (INIS)

Matzen, M.K.

1997-01-01

Fast z-pinch implosions can convert more than 10% of the stored electrical energy in a pulsed-power accelerator into x rays. These x rays are produced when an imploding cylindrical plasma, driven by the magnetic field pressure associated with very large axial currents, stagnates upon the cylindrical axis of symmetry. On the Saturn pulsed-power accelerator at Sandia National Laboratories, for example, currents of 6 to 8 MA with a risetime of less than 50 ns are driven through cylindrically-symmetric loads, producing implosions velocities as high as 100 cm/μs and x-ray energies as high as 500 kJ. The keV component of the resulting x-ray spectrum has been used for many years 8 a radiation source for material response studies. Alternatively, the x-ray output can be thermalized into a near-Planckian x-ray source by containing it within a large cylindrical radiation case. These large volume, long-lived radiation sources have recently been used for ICF-relevant ablator physics experiments as well as astrophysical opacity and radiation-material interaction experiments. Hydromagnetic Rayleigh-Taylor instabilities and cylindrical load symmetry are critical, limiting factors in determining the assembled plasma densities and temperatures, and thus in the x-ray pulse widths that can be produced on these accelerators. In recent experiments on the Saturn accelerator, these implosion nonuniformities have been minimized by using uniform-fill gas puff loads or by using wire arrays with as many a 192 wires. These techniques produced significant improvements in the pinched plasma quality, Zn reproducibility, and x-ray output power. X-ray pulse widths of less than 5 ns and peak powers of 75±10 TW have been achieved with arrays of 120 tungsten wires. These powers represent greater than a factor of three in power amplification over the electrical power of the Saturn n accelerator, and are a record for x-ray powers in the laboratory

Parabolic crossed planar polymeric x-ray lenses

Science.gov (United States)

Nazmov, V.; Reznikova, E.; Mohr, J.; Saile, V.; Vincze, L.; Vekemans, B.; Bohic, S.; Somogyi, A.

2011-01-01

The principles of design and manufacturing of the polymer planar x-ray lenses focusing in one and two directions, as well as the peculiarities of optical behaviors and the results of the lens test are reported in this paper. The methods of electron and deep x-ray lithography used in lens manufacturing allow the manufacture of ten or more x-ray lenses on one substrate; the lenses show focal lengths down to several centimeters for photon energies between 5 and 40 keV. The measured focus size was 105 nm for a linear lens with an intensity gain of about 407, and 300 × 770 nm for a crossed lens with an intensity gain of 6470.

Supersonic Heat Wave Propagation in Laser-Produced Underdense Plasma for Efficient X-Ray Generation