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Sample records for monitor pulsed sources

  1. Wide-range monitor for pulsed x-ray sources

    Energy Technology Data Exchange (ETDEWEB)

    Kaifer, R.C.; Jenkins, T.E.; Straume, T.

    1981-10-12

    A monitoring instrument based on a high-pressure ionization chamber has been developed that measures average dose rates as low as 0.1 mR/h and responds linearly to short pulses at dose rates up to 1.2 x 10/sup 10/ R/h. Its sensitivity can be remotely changed by a factor of 10/sup 4/, to enable accurate measurement of both background radiation and very high intensities such as can be expected from accelerator beam-spills. The instrument's detector-electrometer pulse response was measured using a dose-calibrated field-emission accelerator having a 30-ns pulse width.

  2. Photopyroelectric Monitoring of Olive's Ripening Conditions and Olive Oil Quality Using Pulsed Wideband IR Thermal Source

    Science.gov (United States)

    Abu-Taha, M. I.; Sarahneh, Y.; Saleh, A. M.

    The present study is based on band absorption of radiation from pulsed wideband infrared (IR) thermal source (PWBS) in conjunction with polyvinylidene fluoride film (PVDF). It is the first time to be employed to monitor the ripening state of olive fruit. Olive's characteristics vary at different stages of ripening, and hence, cultivation of olives at the right time is important in ensuring the best oil quality and maximizes the harvest yield. The photopyroelectric (PPE) signal resulting from absorption of wideband infrared (IR) radiation by fresh olive juice indicates the ripening stage of olives, i.e., allows an estimate of the suitable harvest time. The technique was found to be very useful in discriminating between olive oil samples according to geographical region, shelf life, some storage conditions, and deliberate adulteration. Our results for monitoring oil accumulation in olives during the ripening season agree well with the complicated analytical studies carried out by other researchers.

  3. A useful method to monitor outputs from a pulsed light source and its application to rate effect studies in a photomultiplier tube

    CERN Document Server

    Takeuchi, Y; Kurashige, H; Matono, Y; Murakami, K; Nomura, T; Sakamoto, H; Sasao, N; Suehiro, M; Fukushima, Y; Ikegami, Y; Nakamura, T T; Taniguchi, T; Asai, M

    1999-01-01

    In order to study short-term gain stability in a photomultiplier tube at high counting rate, we constructed an LED pulsed light source and its output monitoring system. For the monitoring system, we employed a photon counting method using a photomultiplier as a monitor photon detector. It is found that the method offers a simple way to monitor outputs from a pulsed light source and that, together with an LED light source, it provides a useful method to investigate photomultiplier's rate effects.

  4. Pulsed spallation Neutron Sources

    Energy Technology Data Exchange (ETDEWEB)

    Carpenter, J.M. [Argonne National Lab., IL (United States)

    1994-12-31

    This paper reviews the early history of pulsed spallation neutron source development at Argonne and provides an overview of existing sources world wide. A number of proposals for machines more powerful than currently exist are under development, which are briefly described. The author reviews the status of the Intense Pulsed Neutron Source, its instrumentation, and its user program, and provides a few examples of applications in fundamental condensed matter physics, materials science and technology.

  5. Pulsed Plasma Electron Sources

    Science.gov (United States)

    Krasik, Yakov

    2008-11-01

    Pulsed (˜10-7 s) electron beams with high current density (>10^2 A/cm^2) are generated in diodes with electric field of E > 10^6 V/cm. The source of electrons in these diodes is explosive emission plasma, which limits pulse duration; in the case E Hadas and Ya. E. Krasik, Europhysics Lett. 82, 55001 (2008).

  6. Pulsed-source MOCVD of high-k dielectric thin films with in situ monitoring by spectroscopic ellipsometry

    CERN Document Server

    Tsuchiya, Y; Tung, R T; Oda, S; Kurosawa, M; Hattori, T

    2003-01-01

    The formation of high-k thin films by pulsed-source metal-organic chemical vapor deposition (MOCVD) has been investigated with in situ spectroscopic ellipsometry. It is demonstrated that spectroscopic ellipsometry is an effective method for in situ monitoring of the fabrication of high-k dielectric thin films with thicknesses of several nm's. Thin yttrium oxide films with average roughnesses smaller than the thickness of a single molecular layer, and with a capacitance equivalent thickness approx 1.7 nm were obtained. Thicknesses and optical properties of each individual layer were also extracted from spectroscopic ellipsometry, by fitting to appropriate structural models. (author)

  7. Intense pulsed neutron source

    Science.gov (United States)

    The IPNS Progress Report 10th Anniversary Edition is being published in recognition of the first ten years of successful IPNS operation. To emphasize the significance of this milestone, we wanted this report to stand apart from the previous IPNS Progress Reports, and the best way to do this, we thought, was to make the design and organization of the report significantly different. In their articles, authors were asked to emphasize not only advances made since IPNS began operating but also the groundwork that was laid at its predecessor facilities - Argonne's ZING-P and ZING-P' prototype pulsed neutron sources and CP-5 reactor. Each article stands as a separate chapter in the report, since each represents a particular instrument or class of instruments, system, technique, or area of research. In some cases, contributions were similar to review articles in scientific journals, complete with extensive lists of references. Ten-year cumulative lists of members of IPNS committees and of scientists who have visited or done experiments at IPNS were assembled. A list of published and 'in press' articles in journals, books, and conference proceedings, resulting from work done at IPNS during the past ten years, was compiled. And archival photographs of people and activities during the ten-year history of IPNS were located and were used liberally throughout the report. The titles of the chapters in this report are: accelerator; computer; radiation effects; powder; stress; single crystal; superconductivity; amorphous; small angle; reflection; quasielastic; inelastic; inelastic magnetic; deep inelastic; user program; the future; and publications.

  8. Rapidly pulsed helium droplet source

    Energy Technology Data Exchange (ETDEWEB)

    Pentlehner, Dominik; Riechers, Ricarda; Dick, Bernhard; Slenczka, Alkwin [Institute for Physical and Theoretical Chemistry, University of Regensburg, 93053 Regensburg (Germany); Even, Uzi; Lavie, Nachum; Brown, Raviv; Luria, Kfir [Sackler Faculty of Exact Sciences, School of Chemistry, Tel Aviv University, Ramat Aviv, 69978 Tel Aviv (Israel)

    2009-04-15

    A pulsed valve connected to a closed-cycle cryostat was optimized for producing helium droplets. The pulsed droplet beam appeared with a bimodal size distribution. The leading part of the pulse consists of droplets suitable for doping with molecules. The average size of this part can be varied between 10{sup 4} and 10{sup 6} helium atoms, and the width of the distribution is smaller as compared to a continuous-flow droplet source. The system has been tested in a single pulse mode and at repetition rates of up to 500 Hz with almost constant intensity. The droplet density was found to be increased by more than an order of magnitude as compared to a continuous-flow droplet source.

  9. Source Monitoring in Alzheimer's Disease

    Science.gov (United States)

    El Haj, Mohamad; Fasotti, Luciano; Allain, Philippe

    2012-01-01

    Source monitoring is the process of making judgments about the origin of memories. There are three categories of source monitoring: reality monitoring (discrimination between self- versus other-generated sources), external monitoring (discrimination between several external sources), and internal monitoring (discrimination between two types of…

  10. Source Monitoring in Alzheimer's Disease

    Science.gov (United States)

    El Haj, Mohamad; Fasotti, Luciano; Allain, Philippe

    2012-01-01

    Source monitoring is the process of making judgments about the origin of memories. There are three categories of source monitoring: reality monitoring (discrimination between self- versus other-generated sources), external monitoring (discrimination between several external sources), and internal monitoring (discrimination between two types of…

  11. Calorimeter for pulsed energy sources

    Energy Technology Data Exchange (ETDEWEB)

    Pearce, J.W.; Edmonds, P.H.

    1979-01-01

    A common problem in plasma physics experiments is the measurement of the energy deposited on a water-cooled plate by a pulsed energy source. Examples of this are neutral-beam-line defining plate and targets and tokamak water-cooled limiters. One method of measuring this energy is to integrate the product of the temperature rise (..delta..T) and the flow rate (F) of the coolant over the interval between the pulses. The two input parameters ..delta..T and F are derived from a differential thermopile and a turbine flow meter, respectively. A simple digital readout circuit displays the deposited energy in a light-emitting diode display. The circuit uses a commercially available, dual-slope analog-to-digital converter (ADC) in a novel configuration that multiplies ..delta..T and F directly. Calibration of the readout circuit is quick and simple, and short-term accuracies of 5% are easily obtained. Over longer periods the accuracy becomes degraded, primarily by thermal drifts in the thermopile amplifier and in the thermopile connections and the wiring. This offset must be compensated for by a simple adjustment before each experimental run. This readout circuit has been used successfully on the Impurity Study Experiment (ISX-B) neutral beam lines and is most convenient for deposited energy measurements in applications in which computerized data acquisition is not available.

  12. Pulse oximetry for perioperative monitoring

    DEFF Research Database (Denmark)

    Pedersen, Tom; Møller, Ann Merete; Hovhannisyan, Karen

    2009-01-01

    Pulse oximetry is extensively used in the perioperative period and might improve patient outcomes by enabling an early diagnosis and, consequently, correction of perioperative events that might cause postoperative complications or even death. Only a few randomized clinical trials of pulse oximetry...

  13. Pulse oximetry for perioperative monitoring

    DEFF Research Database (Denmark)

    Pedersen, Tom; Nicholson, Amanda; Hovhannisyan, Karen

    2014-01-01

    . Results indicated that hypoxaemia was reduced in the pulse oximetry group, both in the operating theatre and in the recovery room. During observation in the recovery room, the incidence of hypoxaemia in the pulse oximetry group was 1.5 to three times less. Postoperative cognitive function was independent...... postoperative complications or even death. Only a few randomized clinical trials of pulse oximetry during anaesthesia and in the recovery room have been performed that describe perioperative hypoxaemic events, postoperative cardiopulmonary complications and cognitive dysfunction. OBJECTIVES: To study the use...... checked the reference lists of trials and review articles. The original search was performed in January 2005, and a previous update was performed in May 2009. SELECTION CRITERIA: We included all controlled trials that randomly assigned participants to pulse oximetry or no pulse oximetry during...

  14. From reactors to long pulse sources

    Energy Technology Data Exchange (ETDEWEB)

    Mezei, F. [Eotvos Univ., Budapest (Hungary)]|[Hahn-Meitner Institut, Berlin (Germany)

    1995-12-31

    We will show, that by using an adapted instrumentation concept, the performance of a continuous source can be emulated by one switch on in long pulses for only about 10% of the total time. This 10 fold gain in neutron economy opens up the way for building reactor like sources with an order of magnitude higher flux than the present technological limits. Linac accelerator driven spallation lends itself favorably for the realization of this kind of long pulse sources, which will be complementary to short pulse spallation sources, the same way continuous reactor sources are.

  15. The pulsing CPSD method for subcritical assemblies with pulsed sources

    CERN Document Server

    Ballester, D; Ballester, Daniel; Munoz-Cobo, Jose L.

    2005-01-01

    Stochastic neutron transport theory is applied to the derivation of the two-neutron-detectors cross power spectral density for subcritical assemblies when external pulsed sources are used. A general relationship between the two-detector probability generating functions of the kernel and the source is obtained considering the contribution to detectors statistics of both the pulsed source and the intrinsic neutron source. An expansion in alpha-eigenvalues is derived for the final solution, which permits to take into account the effect of higher harmonics in subcritical systems. Further, expressions corresponding to the fundamental mode approximation are compared with recent results from experiments performed under the MUSE-4 European research project.

  16. WORKING FEATURES OF POWER SOURCE SYSTEMS – A MULTIPLE CURRENT PULSE GENERATOR

    Directory of Open Access Journals (Sweden)

    Shs.V. Argun

    2013-04-01

    Full Text Available An analysis of circuit designs as to connecting a magnetic pulse action tool to a power source has been carried out. Design features of a magnetic pulse installation control and monitoring system in a multiple current pulse mode have been revealed. The description of the control and monitoring system block diagrams has been presented.

  17. Field mapping of ballistic pressure pulse sources

    Directory of Open Access Journals (Sweden)

    Rad Abtin Jamshidi

    2015-09-01

    Full Text Available Ballistic pressure pulse sources are used since late 1990s for the extracorporeal treatment of chronic Enthesitis. Newly indications are found in trigger-point-therapy for the treatment of musculoskeletal disorders. In both applications excellent results without relevant side effects were found in clinical trials. The technical principle of pressure pulse source is based on the same techniques used in air guns. A projectile is accelerated by pressurized air and hits the applicator with high kinetic energy. By this a compression wave travels through the material and induces a fast (4..5μs, almost singular pressure pulse of 2..10 MPa, which is followed by an equally short rarefaction phase of about the same amplitude. It is assumed that the pressure pulse accounts for the biomedical effects of the device. The slower inertial motion of the waveguide is damped by elastic stoppers, but still can be measured several micro seconds after the initial pressure pulse. In order to characterize the pressure pulse devices, field mapping is performed on several radial pressure pulse sources using the fiber optic hydrophone and a polyvinylidenfluorid (PVDF piezoelectric hydrophone. It could be shown that the current standard (IEC 61846 is not appropriate for characterization of ballistic pressure pulse sources.

  18. The Compact Pulsed Hadron Source Construction Status

    CERN Document Server

    Wei, Jie; Cai, Jinchi; Chen, Huaibi; Cheng, Cheng; Du, Qiang; Du, Taibin; Feng, Qixi; Feng, Zhe; Gong, Hui; Guan, Xialing; Han, Xiaoxue; Huang, Tuchen; Huang, Zhifeng; Li, Renkai; Li, Wenqian; Loong, Chun-Keung; Tang, Chuanxiang; Tian, Yang; Wang, Xuewu; Xie, Xiaofeng; Xing, Qingzi; Xiong, Zhengfeng; Xu, Dong; Yang, Yigang; Zeng, Zhi; Zhang, Huayi; Zhang, Xiaozhang; Zheng, Shu-xin; Zheng, Zhihong; Zhong, Bin; Billen, James; Young, Lloyd; Fu, Shinian; Tao, Juzhou; Zhao, Yaliang; Guan, Weiqiang; He, Yu; Li, Guohua; Li, Jian; Zhang, Dong-sheng; Li, Jinghai; Liang, Tianjiao; Liu, Zhanwen; Sun, Liangting; Zhao, Hongwei; Shao, Beibei; Stovall, James

    2010-01-01

    This paper reports the design and construction status, technical challenges, and future perspectives of the proton-linac based Compact Pulsed Hadron Source (CPHS) at the Tsinghua University, Beijing, China

  19. Future opportunities with pulsed neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, A.D. [Rutherford Appleton Lab., Chilton (United Kingdom)

    1996-05-01

    ISIS is the world`s most powerful pulsed spallation source and in the past ten years has demonstrated the scientific potential of accelerator-driven pulsed neutron sources in fields as diverse as physics, earth sciences, chemistry, materials science, engineering and biology. The Japan Hadron Project gives the opportunity to build on this development and to further realize the potential of neutrons as a microscopic probe of the condensed state. (author)

  20. Pulse radiolysis apparatus for monitoring at 2000 Å

    DEFF Research Database (Denmark)

    Christensen, H.C.; Nilsson, G.; Pagsberg, Palle Bjørn

    1969-01-01

    A pulse radiolysis apparatus with photometric monitoring has been built around an 11 MeV, 250 mA peak current, linac that delivers single 0.25 to 4 μsec pulses. The novel features of the apparatus include (1) a 450 W xenon lamp as the analyzing light source which in pulsed operation had a 25 times...... increased luminance; (2) a fast electronic switch that cut out the signal due to the Cerenkov radiation; (3) a secondary emission chamber that allowed the simultaneous measurement of the current and the direction of the pulsed electron beam; and (4) a system for remote controlled change of liquid samples...... stored in glass syringes. Reliable measurements of optical transmission could be made starting 0.2 μsec after the electron pulse at wavelengths down to 2000 Å on transient species having products of yield and absorptivity G×ε>500 mole (100 eV)-1.liter-1.cm-1...

  1. Neutronics of pulsed spallation neutron sources

    CERN Document Server

    Watanabe, N

    2003-01-01

    Various topics and issues on the neutronics of pulsed spallation neutron sources, mainly for neutron scattering experiments, are reviewed to give a wide circle of readers a better understanding of these sources in order to achieve a high neutronic performance. Starting from what neutrons are needed, what the spallation reaction is and how to produce slow-neutrons more efficiently, the outline of the target and moderator neutronics are explained. Various efforts with some new concepts or ideas have already been devoted to obtaining the highest possible slow-neutron intensity with desired pulse characteristics. This paper also reviews the recent progress of such efforts, mainly focused on moderator neutronics, since moderators are the final devices of a neutron source, which determine the source performance. Various governing parameters for neutron-pulse characteristics such as material issues, geometrical parameters (shape and dimensions), the target-moderator coupling scheme, the ortho-para-hydrogen ratio, po...

  2. Extracting source parameters from beam monitors on a chopper spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Abernathy, Douglas L [ORNL; Niedziela, Jennifer L [ORNL; Stone, Matthew B [ORNL

    2015-01-01

    The intensity distributions of beam monitors in direct-geometry time-of-flight neutron spectrometers provide important information about the instrument resolution. For short-pulse spallation neutron sources in particular, the asymmetry of the source pulse may be extracted and compared to Monte Carlo source simulations. An explicit formula using a Gaussian-convolved Ikeda-Carpenter distribution is given and compared to data from the ARCS instrument at the Spallation Neutron Source.

  3. Long-pulse Supercontinuum Light Sources

    DEFF Research Database (Denmark)

    Moselund, Peter M.

    A Supercontinuum (SC) is a broad spectrum generated from a narrow light source through non-linear effects. This thesis describes SC generation based on 1064 nm ps pulses in PCF fibres. We investigate how the SC spectrum can be modified and intensity noise reduced by feeding back part of the SC...

  4. REM meter for pulsed sources of neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Thorngate, J.E.; Hunt, G.F.; Rueppel, D.W.

    1980-08-13

    A rem meter was constructed specifically for measuring neutrons produced by fusion experiments for which the source pulses last 10 ms or longer. The detector is a /sup 6/Li glass scintillator, 25.4 mm in diameter and 3.2 mm thick, surrounded by 11.5 cm of polyethylene. This detector has a sensitivity of 8.5 x 10/sup 4/ counts/mrem. The signals from this fast scintillator are shaped using a shorted delay line to produce pulses that are only 10 ns long so that dose equivalent rates up to 12 mrem/s can be measured with less than a 1% counting loss. The associated electronic circuits store detector counts only when the count rate exceeds a preset level. When the count rate returns to background, a conversion from counts to dose equivalent is made and the results are displayed. As a means of recording the number of source pulses that have occurred, a second display shows how many times the preset count rate has been exceeded. Accumulation of detector counts and readouts can also be controlled manually. The unit will display the integrated dose equilavent up to 200 mrem in 0.01 mrem steps. A pulse-height discriminator rejects gamma-ray interactions below 1 MeV, and the detector size limits the response above that energy. The instrument can be operated from an ac line or will run on rechargeable batteries for up to 12 hours.

  5. Advanced Pulse Oximetry System for Remote Monitoring and Management

    Directory of Open Access Journals (Sweden)

    Ju Geon Pak

    2012-01-01

    Full Text Available Pulse oximetry data such as saturation of peripheral oxygen (SpO2 and pulse rate are vital signals for early diagnosis of heart disease. Therefore, various pulse oximeters have been developed continuously. However, some of the existing pulse oximeters are not equipped with communication capabilities, and consequently, the continuous monitoring of patient health is restricted. Moreover, even though certain oximeters have been built as network models, they focus on exchanging only pulse oximetry data, and they do not provide sufficient device management functions. In this paper, we propose an advanced pulse oximetry system for remote monitoring and management. The system consists of a networked pulse oximeter and a personal monitoring server. The proposed pulse oximeter measures a patient’s pulse oximetry data and transmits the data to the personal monitoring server. The personal monitoring server then analyzes the received data and displays the results to the patient. Furthermore, for device management purposes, operational errors that occur in the pulse oximeter are reported to the personal monitoring server, and the system configurations of the pulse oximeter, such as thresholds and measurement targets, are modified by the server. We verify that the proposed pulse oximetry system operates efficiently and that it is appropriate for monitoring and managing a pulse oximeter in real time.

  6. Pulse source requirements for OTDM systems

    DEFF Research Database (Denmark)

    Clausen, Anders; Poulsen, Henrik Nørskov; Oxenløwe, Leif Katsuo

    2003-01-01

    A simulation model for investigating the impact of incoherent crosstalk due to pulse tail overlapping is proposed. Requirements to pulse width and pulse tail extinction ratio introducing a maximum of 1 dB penalty is extracted....

  7. Pulsed-Source Interferometry in Acoustic Imaging

    Science.gov (United States)

    Shcheglov, Kirill; Gutierrez, Roman; Tang, Tony K.

    2003-01-01

    A combination of pulsed-source interferometry and acoustic diffraction has been proposed for use in imaging subsurface microscopic defects and other features in such diverse objects as integrated-circuit chips, specimens of materials, and mechanical parts. A specimen to be inspected by this technique would be mounted with its bottom side in contact with an acoustic transducer driven by a continuous-wave acoustic signal at a suitable frequency, which could be as low as a megahertz or as high as a few hundred gigahertz. The top side of the specimen would be coupled to an object that would have a flat (when not vibrating) top surface and that would serve as the acoustical analog of an optical medium (in effect, an acoustical "optic").

  8. Optical polarizing neutron devices designed for pulsed neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, M.; Kurahashi, K.; Endoh, Y. [Tohoku Univ, Sendai (Japan); Itoh, S. [National Lab. for High Energy Physics, Tsukuba (Japan)

    1997-09-01

    We have designed two polarizing neutron devices for pulsed cold neutrons. The devices have been tested at the pulsed neutron source at the Booster Synchrotron Utilization Facility of the National Laboratory for High Energy Physics. These two devices proved to have a practical use for experiments to investigate condensed matter physics using pulsed cold polarized neutrons.

  9. LAT Monitored Source List Light Curves

    Data.gov (United States)

    National Aeronautics and Space Administration — The LAT team monitors flux values for a number of bright sources and transient sources that have shown flares during the mission. (See up-to-date weekly reports on...

  10. Pulsed microhollow cathode discharge excimer sources

    Science.gov (United States)

    Moselhy, Mohamed; Shi, Wenhui; Strak, Robert H.; Schoenbach, Karl H.

    2001-10-01

    Microhollow cathode discharges (MHCDs) are non-equilibrium, high-pressure gas discharges between perforated electrodes separated by a dielectric layer. Typical dimensions for the electrode foil thickness and hole diameter are 100 μm. Direct current experiments in xenon, argon, neon, helium, argon fluoride, and xenon chloride [1,2] have been performed. The excimer efficiency varies between 1 % and 9 %. Pulsed operation allowed us to increase the current from 8 mA (dc) to approximately 80 mA (pulsed with a pulse width of 700 μs), limited by the onset of instabilities. The total excimer power was found to increase linearly with current, however, the radiant emittance and efficiency stayed constant. Reducing the pulse duration into the nanosecond range allowed us to increase the current into the ampere range. The maximum measured excimer power was 2.75 W per microdischarge. The maximum radiant emittance was 15 W/cm^2 and the efficiency reached values of 20 %. This effect is assumed to be due to non-equilibrium electron heating in the high-pressure plasma [3]. This work was supported by the National Science Foundation under grant # CTS0078618. 1. Karl H. Schoenbach, Ahmed El-Habachi, Mohamed M. Moselhy, Wenhui Shi, and Robert H. Stark, Physics of Plasmas 7, 2186 (2000). 2. P. Kurunczi, J. Lopez, H. Shah, and K. Becker, Int. J. Mass Spectrom. 205, 277 (2001). 3. Robert H. Stark and Karl H. Schoenbach, J. Appl. Phys. 89, 3568 (2001).

  11. Miniature, Rugged, Pulsed Laser Source for LIDAR Application Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Princeton Optronics proposes to develop a high energy pulsed laser source based on a novel approach. The approach consists of a technique to combine a large number...

  12. VUV SOURCE FROM PULSED-LASER GENERATED PLASMA

    OpenAIRE

    Laporte, P.; Damany, N.; Damany, H.

    1987-01-01

    We describe a pulsed vacuum ultraviolet (VUV) source consisting of a plasma created by focusing a NdYAG laser beam into rare gases under moderate pressure, and we report on spectral and time properties of that source. Main features are : continuum emission in a large spectral range, with only few lines superimposed, good time characteristics of the pulses, stability, cleanliness, and relatively high repetition rate (20 Hz).

  13. Clinical evaluation of pulse oximetry monitors on critically ill patients.

    Science.gov (United States)

    De Pauw, C; Poelaert, J; Rolly, G; Colardyn, F

    1990-01-01

    Four pulse oximeters and two pulse oximeter-capnographs were evaluated on accuracy of measuring oxygen saturation and heartrate for the former and oxygen saturation, heartrate, respiratory rate and capnography for the latter. In the first part of the study four pulse oximeters (Criticare Systems Model 501 +, Ohmeda Biox 3700 Pulse Oximeter, Nellcor Model N 100 and Datex Satlite) were simultaneously studied on 10 ventilated ICU patients. Fifty simultaneous measurements were done for heartrate and oxygen saturation and compared to arterial saturations and ECG heartrates. Mean differences from pulse oximeter values versus control arterial and ECG values were within two percent for the four instruments. In the second part two oxicaps (Ohmeda 4700 and Nellcor N 1000) were evaluated with the same control parameters. Thirty measurements on 3 patients were done. As in the first part of the study all results were accurate within two percent of control values. From those data we can conclude that all examined monitors were fairly accurate compared to simultaneous arterial blood gas analysis and ECG monitoring. The oxicap monitors have the advantage of giving continuous information on two very important parameters of patient monitoring: CO2 and saturation.

  14. Modulated Pulsed Laser Sources for Imaging Lidars

    Science.gov (United States)

    2007-10-01

    manufactured by QPC. This C-mount device has a monolithic semiconductor amplifier allowing the package to output up to 1.5 Watts at 1064 nm with linewidths ɘ.1...pulsed driver based on the avalanche transistor circuit being used for gain switching, a 1064 nm DFB laser manufactured by QPC and a DBR -style laser...available now that may provide the needed power. An example of such a laser is the QPC C-mount monolithic oscillator/amplifier which can output 1.5

  15. Fissile mass estimation by pulsed neutron source interrogation

    Energy Technology Data Exchange (ETDEWEB)

    Israelashvili, I., E-mail: israelashvili@gmail.com [Nuclear Research Center of the Negev, P.O.B 9001, Beer Sheva 84190 (Israel); Dubi, C.; Ettedgui, H.; Ocherashvili, A. [Nuclear Research Center of the Negev, P.O.B 9001, Beer Sheva 84190 (Israel); Pedersen, B. [Nuclear Security Unit, Institute for Transuranium Elements, Joint Research Centre, Via E. Fermi, 2749, 21027 Ispra (Italy); Beck, A. [Nuclear Research Center of the Negev, P.O.B 9001, Beer Sheva 84190 (Israel); Roesgen, E.; Crochmore, J.M. [Nuclear Security Unit, Institute for Transuranium Elements, Joint Research Centre, Via E. Fermi, 2749, 21027 Ispra (Italy); Ridnik, T.; Yaar, I. [Nuclear Research Center of the Negev, P.O.B 9001, Beer Sheva 84190 (Israel)

    2015-06-11

    Passive methods for detecting correlated neutrons from spontaneous fissions (e.g. multiplicity and SVM) are widely used for fissile mass estimations. These methods can be used for fissile materials that emit a significant amount of fission neutrons (like plutonium). Active interrogation, in which fissions are induced in the tested material by an external continuous source or by a pulsed neutron source, has the potential advantages of fast measurement, alongside independence of the spontaneous fissions of the tested fissile material, thus enabling uranium measurement. Until recently, using the multiplicity method, for uranium mass estimation, was possible only for active interrogation made with continues neutron source. Pulsed active neutron interrogation measurements were analyzed with techniques, e.g. differential die away analysis (DDA), which ignore or implicitly include the multiplicity effect (self-induced fission chains). Recently, both, the multiplicity and the SVM techniques, were theoretically extended for analyzing active fissile mass measurements, made by a pulsed neutron source. In this study the SVM technique for pulsed neutron source is experimentally examined, for the first time. The measurements were conducted at the PUNITA facility of the Joint Research Centre in Ispra, Italy. First promising results, of mass estimation by the SVM technique using a pulsed neutron source, are presented.

  16. Ultrashort pulse laser technology laser sources and applications

    CERN Document Server

    Schrempel, Frank; Dausinger, Friedrich

    2016-01-01

    Ultrashort laser pulses with durations in the femtosecond range up to a few picoseconds provide a unique method for precise materials processing or medical applications. Paired with the recent developments in ultrashort pulse lasers, this technology is finding its way into various application fields. The book gives a comprehensive overview of the principles and applications of ultrashort pulse lasers, especially applied to medicine and production technology. Recent advances in laser technology are discussed in detail. This covers the development of reliable and cheap low power laser sources as well as high average power ultrashort pulse lasers for large scale manufacturing. The fundamentals of laser-matter-interaction as well as processing strategies and the required system technology are discussed for these laser sources with respect to precise materials processing. Finally, different applications within medicine, measurement technology or materials processing are highlighted.

  17. 1579 NM Fiber Laser Source for Spaceborne Monitoring of Carbon Dioxide

    Directory of Open Access Journals (Sweden)

    Cézard Nicolas

    2016-01-01

    Full Text Available We report on the development of a 1579 nm pulsed fiber laser source with high peak-power, intended to be used as a lidar source for CO2 monitoring from space. We first discuss water-vapor sensitivity of spaceborne CO2 measurements by lidar and point the interest of the 1579 nm wavelength with that respect. Then we detail the current development status of the pulsed fiber laser source.

  18. Pulsed neutron source based on accelerator-subcritical-assembly

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Makoto; Noda, Akira; Iwashita, Yoshihisa; Okamoto, Hiromi; Shirai, Toshiyuki [Kyoto Univ., Uji (Japan). Inst. for Chemical Research

    1997-03-01

    A new pulsed neutron source which consists of a 300MeV proton linac and a nuclear fuel subcritical assembly is proposed. The proton linac produces pulsed spallation neutrons, which are multipied by the subcritical assembly. A prototype proton linac that accelerates protons up to 7MeV has been developed and a high energy section of a DAW structure is studied with a power model. Halo formations in high intensity beam are also being studied. (author)

  19. Long-pulse operation of an intense negative ion source

    Energy Technology Data Exchange (ETDEWEB)

    Takeiri, Yasuhiko; Osakabe, Masaki; Tsumori, Katsuyoshi; Kaneko, Osamu; Oka, Yoshihide; Asano, Eiji; Kawamoto, Toshikazu; Akiyama, Ryuichi; Kuroda, Tsutomu [National Inst. for Fusion Science, Nagoya (Japan)

    1997-02-01

    In the National Institute for Fusion Science, as the heating system for the Large Helical Device (LHD), the negative ion NBI system of 20 MW incident power has been planned, and the development of a large current, large size negative ion source has been advanced. Based on the results obtained so far, the design of the LHD-NBI system was reconsidered, and the specification of the actual negative ion source was decided as 180 KeV-40A. This time, the grounding electrode with heightened heat removal capacity was made, and the long pulse operation was attempted, therefore, its results are reported. The structure of the external magnetic filter type large negative ion source used for the long pulse experiment is explained. In order to form the negative ion beam of long pulses, it is necessary to form stable are discharge plasma for long time, and variable resistors were attached to the output side of arc power sources of respective filament systems. By adjusting the resistors, uniform are discharge was able to be caused for longer than 10 s stably. The results of the long pulse experiment are reported. The dependence of the characteristics of negative ion beam on plasma electrode temperature was small, and the change of the characteristics of negative ion beam due to beam pulse width was not observed. (K.I.)

  20. Monitoring of solidification crack propagation mechanism in pulsed laser welding of 6082 aluminum

    Science.gov (United States)

    von Witzendorff, P.; Kaierle, S.; Suttmann, O.; Overmeyer, L.

    2016-03-01

    Pulsed laser sources with pulse durations in the millisecond regime can be used for spot welding and seam welding of aluminum. Seam welds are generally produced with several overlapping spot welds. Hot cracking has its origin in the solidification process of individual spot welds which determines the cracking morphology along the seam welding. This study used a monitoring unit to capture the crack geometry within individual spot welds during seam welding to investigate the conditions for initiation, propagation and healing (re-melting) of solidification cracking within overlapping pulsed laser welds. The results suggest that small crack radii and high crack angles with respect to welding direction are favorable conditions for crack healing which leads to crack-free seam welds. Optimized pulse shapes were used to produce butt welds of 0.5 mm thick 6082 aluminum alloys. Tensile tests were performed to investigate the mechanical strength in the as-welded condition.

  1. Pulsed electron source characterization with the modified three gradient method

    CERN Document Server

    Marghitu, S; Dinca, C; Marghitu, O

    2001-01-01

    Results from the Modified Three Gradient Method (MTGM), applied to a pulsed high intensity electron source, are presented. The MTGM makes possible the non-destructive determination of beam emittance in the space charge presence [1]. We apply the MTGM to an experimental system equipped with a Pierce convergent diode, working in pulse mode, and having a directly heated cathode as electron source. This choice was mainly motivated by the availability of an analytical characterization of this source type [2], as well as the extended use of the Pierce type sources in linear accelerators. The experimental data are processed with a numerical matching program, based on the K-V equation for an axially symmetric configuration [3], to determine the emittance and object cross-over position and diameter. The variation of these parameters is further investigated with respect to both electrical and constructive characteristics of the source: cathode heating current, extraction voltage, and cathode-anode distance.

  2. Development of advanced radiation monitors for pulsed neutron fields

    CERN Document Server

    AUTHOR|(CDS)2081895

    The need of radiation detectors capable of efficiently measuring in pulsed neutron fields is attracting widespread interest since the 60s. The efforts of the scientific community substantially increased in the last decade due to the increasing number of applications in which this radiation field is encountered. This is a major issue especially at particle accelerator facilities, where pulsed neutron fields are present because of beam losses at targets, collimators and beam dumps, and where the correct assessment of the intensity of the neutron fields is fundamental for radiation protection monitoring. LUPIN is a neutron detector that combines an innovative acquisition electronics based on logarithmic amplification of the collected current signal and a special technique used to derive the total number of detected neutron interactions, which has been specifically conceived to work in pulsed neutron fields. Due to its special working principle, it is capable of overcoming the typical saturation issues encountere...

  3. Shutterless ion mobility spectrometer with fast pulsed electron source

    Science.gov (United States)

    Bunert, E.; Heptner, A.; Reinecke, T.; Kirk, A. T.; Zimmermann, S.

    2017-02-01

    Ion mobility spectrometers (IMS) are devices for fast and very sensitive trace gas analysis. The measuring principle is based on an initial ionization process of the target analyte. Most IMS employ radioactive electron sources, such as 63Ni or 3H. These radioactive materials have the disadvantage of legal restrictions and the electron emission has a predetermined intensity and cannot be controlled or disabled. In this work, we replaced the 3H source of our IMS with 100 mm drift tube length with our nonradioactive electron source, which generates comparable spectra to the 3H source. An advantage of our emission current controlled nonradioactive electron source is that it can operate in a fast pulsed mode with high electron intensities. By optimizing the geometric parameters and developing fast control electronics, we can achieve very short electron emission pulses for ionization with high intensities and an adjustable pulse width of down to a few nanoseconds. This results in small ion packets at simultaneously high ion densities, which are subsequently separated in the drift tube. Normally, the required small ion packet is generated by a complex ion shutter mechanism. By omitting the additional reaction chamber, the ion packet can be generated directly at the beginning of the drift tube by our pulsed nonradioactive electron source with only slight reduction in resolving power. Thus, the complex and costly shutter mechanism and its electronics can also be omitted, which leads to a simple low-cost IMS-system with a pulsed nonradioactive electron source and a resolving power of 90.

  4. 40 CFR 141.701 - Source water monitoring.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Source water monitoring. 141.701... Monitoring Requirements § 141.701 Source water monitoring. (a) Initial round of source water monitoring... sampling frequency is evenly spaced throughout the monitoring period. (b) Second round of source water...

  5. Soliton filtering from a supercontinuum: a tunable femtosecond pulse source

    Energy Technology Data Exchange (ETDEWEB)

    Licea-Rodriguez, Jacob; Rangel-Rojo, Raul [Centro de Investigacion CientIfica y de Educacion Superior de Ensenada, Apartado Postal 2732, Ensenada B.C., 22860 (Mexico); Garay-Palmett, Karina, E-mail: rrangel@cicese.mx [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-543, Mexico DF. 04510 (Mexico)

    2011-01-01

    In this article we report experimental results related with the generation of a supercontinuum in a microstructured fiber, from which the soliton with the longest wavelength is filtered out of the continuum and is used to construct a tunable ultrashort pulses source by varying the pump power. Pulses of an 80 fs duration (FWHM) from a Ti:sapphire oscillator were input into a 2 m long fiber to generate the continuum. The duration of the solitons at the fiber output was preserved by using a zero dispersion filtering system, which selected the longest wavelength soliton, while avoiding temporal spreading of the solitons. We present a complete characterization of the filtered pulses that are continuously tunable in the 850-1100 nm range. We also show that the experimental results have a qualitative agreement with theory. An important property of the proposed near-infrared pulsed source is that the soliton pulse energies obtained after filtering are large enough for applications in nonlinear microscopy.

  6. 1030-nm diode-laser-based light source delivering pulses with nanojoule energies and picosecond duration adjustable by mode locking or pulse gating operation

    Science.gov (United States)

    Klehr, A.; Liero, A.; Wenzel, H.; Bugge, F.; Brox, O.; Fricke, J.; Ressel, P.; Knigge, A.; Heinrich, W.; Tränkle, G.

    2017-02-01

    A new compact 1030 nm picosecond light source which can be switched between pulse gating and mode locking operation is presented. It consists of a multi-section distributed Bragg reflector (DBR) laser, an ultrafast multisection optical gate and a flared power amplifier (PA), mounted together with high frequency electronics and optical elements on a 5×4 cm micro bench. The master oscillator (MO) is a 10 mm long ridge wave-guide (RW) laser consisting of 200 μm long saturable absorber, 1500 μm long gain, 8000 μm long cavity, 200 μm long DBR and 100 μm long monitor sections. The 2 mm long optical gate consisting of several RW sections is monolithically integrated with the 4 mm long gain-guided tapered amplifier on a single chip. The light source can be switched between pulse gating and passive mode locking operation. For pulse gating all sections of the MO (except of the DBR and monitor sections) are forward biased and driven by a constant current. By injecting electrical pulses into one section of the optical gate the CW beam emitted by the MO is converted into a train of optical pulses with adjustable widths between 250 ps and 1000 ps. Peak powers of 20 W and spectral linewidths in the MHz range are achieved. Shorter pulses with widths between 4 ps and 15 ps and peak powers up to 50 W but larger spectral widths of about 300 pm are generated by mode locking where the saturable absorber section of the MO is reversed biased. The repetition rate of 4.2 GHz of the pulse train emitted by the MO can be reduced to values between 1 kHz and 100 MHz by utilizing the optical gate as pulse picker. The pulse-to-pulse distance can be controlled by an external trigger source.

  7. Miniaturized pulse oximeter sensor for continuous vital parameter monitoring

    Science.gov (United States)

    Fiala, Jens; Reichelt, Stephan; Werber, Armin; Bingger, Philipp; Zappe, Hans; Förster, Katharina; Klemm, Rolf; Heilmann, Claudia; Beyersdorf, Friedhelm

    2007-07-01

    A miniaturized photoplethysmographic sensor system which utilizes the principle of pulse oximetry is presented. The sensor is designed to be implantable and will permit continuous monitoring of important human vital parameters such as arterial blood oxygen saturation as well as pulse rate and shape over a long-term period in vivo. The system employs light emitting diodes and a photo transistor embedded in a transparent elastic cu. which is directly wrapped around an arterial vessel. This paper highlights the specific challenges in design, instrumentation, and electronics associated with that sensor location. In vitro measurements were performed using an artificial circulation system which allows for regulation of the oxygen saturation and pulsatile pumping of whole blood through a section of a domestic pig's arterial vessel. We discuss our experimental results compared to reference CO-oximeter measurements and determine the empirical calibration curve. These results demonstrate the capabilities of the pulse oximeter implant for measurement of a wide range of oxygen saturation levels and pave the way for a continuous and mobile monitoring of high-risk cardiovascular patients.

  8. Noninvasive continuous monitoring of digital pulse waves during hemodialysis

    DEFF Research Database (Denmark)

    Burkert, Antje; Scholze, Alexandra; Tepel, Martin

    2009-01-01

    Intermittent hemodynamic instability during hemodialysis treatment is a frequent complication in patients with end-stage renal failure. A noninvasive method for continuous hemodynamic monitoring is needed. We used noninvasive digital photoplethysmography and an algorithm for continuous, investiga......Intermittent hemodynamic instability during hemodialysis treatment is a frequent complication in patients with end-stage renal failure. A noninvasive method for continuous hemodynamic monitoring is needed. We used noninvasive digital photoplethysmography and an algorithm for continuous......, investigator-independent, automatic analysis of digital volume pulse in 10 healthy subjects and in 20 patients with end-stage renal failure during the hemodialysis session. The reflective index was defined representing the diastolic component of the digital pulse wave. The properties of the reflective index...... were studied in healthy control subjects (n=10). An increased reflective index was due to increased peripheral pulse wave reflection (e.g., vasoconstriction). During a hemodialysis session, the reflective index increased significantly from 36+/-3 arbitrary units to 41+/-3 arbitrary units (n=20; p...

  9. Ultrafast control and monitoring of material properties using terahertz pulses

    Energy Technology Data Exchange (ETDEWEB)

    Bowlan, Pamela Renee [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Lab. for Ultrafast Materials Optical Science (LUMOS)

    2016-05-02

    These are a set of slides on ultrafast control and monitoring of material properties using terahertz pulses. A few of the topics covered in these slides are: How fast is a femtosecond (fs), Different frequencies probe different properties of molecules or solids, What can a THz pulse do to a material, Ultrafast spectroscopy, Generating and measuring ultrashort THz pulses, Tracking ultrafast spin dynamics in antiferromagnets through spin wave resonances, Coherent two-dimensional THz spectroscopy, and Probing vibrational dynamics at a surface. Conclusions are: Coherent two-dimensional THz spectroscopy: a powerful approach for studying coherence and dynamics of low energy resonances. Applying this to graphene we investigated the very strong THz light mater interaction which dominates over scattering. Useful for studying coupled excitations in multiferroics and monitoring chemical reactions. Also, THz-pump, SHG-probe spectoscopy: an ultrafast, surface sensitive probe of atomic-scale symmetry changes and nonlinear phonon dymanics. We are using this in Bi2Se3 to investigate the nonlinear surface phonon dynamics. This is potentially very useful for studying catalysis.

  10. High Energy Sources Monitored with OMC

    CERN Document Server

    Risquez, D; Caballero-Garcia, M D; Alfonso-Garzon, J; Mas-Hesse, J M

    2008-01-01

    The Optical Monitoring Camera on-board INTEGRAL (OMC) provides Johnson V band photometry of any potentially variable source within its field of view. Taking advantage of the INTEGRAL capabilities allowing the simultaneous observation of different kind of objects in the optical, X and gamma rays bands, we have performed a study of the optical counterparts of different high-energy sources. Up to now, OMC has detected the optical counterpart for more than 100 sources from the High Energy Catalog (Ebisawa et al., 2003). The photometrically calibrated light curves produced by OMC can be accessed through our web portal at: http://sdc.laeff.inta.es/omc

  11. Plasma shape control by pulsed solenoid on laser ion source

    Science.gov (United States)

    Sekine, M.; Ikeda, S.; Romanelli, M.; Kumaki, M.; Fuwa, Y.; Kanesue, T.; Hayashizaki, N.; Lambiase, R.; Okamura, M.

    2015-09-01

    A Laser ion source (LIS) provides high current heavy ion beams with a very simple mechanical structure. Plasma is produced by a pulsed laser ablation of a solid state target and ions are extracted by an electric field. However, it was difficult to manipulate the beam parameters of a LIS, since the plasma condition could only be adjusted by the laser irradiation condition. To enhance flexibility of LIS operation, we employed a pulsed solenoid in the plasma drift section and investigated the effect of the solenoid field on singly charged iron beams. The experimentally obtained current profile was satisfactorily controlled by the pulsed magnetic field. This approach may also be useful to reduce beam emittance of a LIS.

  12. Plasma shape control by pulsed solenoid on laser ion source

    Energy Technology Data Exchange (ETDEWEB)

    Sekine, M. [Tokyo Institute of Technology, Meguro-ku, Tokyo 2-12-1 (Japan); RIKEN, Wako, Saitama 351-0198 (Japan); Ikeda, S. [Tokyo Institute of Technology, Yokohama, Kanagawa 226-8502 (Japan); RIKEN, Wako, Saitama 351-0198 (Japan); Romanelli, M. [Cornell University, Ithaca, NY 14850 (United States); Kumaki, M. [RIKEN, Wako, Saitama 351-0198 (Japan); Waseda University, Shinjuku, Tokyo 169-0072 (Japan); Fuwa, Y. [RIKEN, Wako, Saitama 351-0198 (Japan); Kyoto University, Uji, Kyoto 611-0011 (Japan); Kanesue, T. [Brookhaven National Laboratory, Upton, NY 11973 (United States); Hayashizaki, N. [Tokyo Institute of Technology, Meguro-ku, Tokyo 2-12-1 (Japan); Lambiase, R. [Brookhaven National Laboratory, Upton, NY 11973 (United States); Okamura, M. [RIKEN, Wako, Saitama 351-0198 (Japan); Brookhaven National Laboratory, Upton, NY 11973 (United States)

    2015-09-21

    A Laser ion source (LIS) provides high current heavy ion beams with a very simple mechanical structure. Plasma is produced by a pulsed laser ablation of a solid state target and ions are extracted by an electric field. However, it was difficult to manipulate the beam parameters of a LIS, since the plasma condition could only be adjusted by the laser irradiation condition. To enhance flexibility of LIS operation, we employed a pulsed solenoid in the plasma drift section and investigated the effect of the solenoid field on singly charged iron beams. The experimentally obtained current profile was satisfactorily controlled by the pulsed magnetic field. This approach may also be useful to reduce beam emittance of a LIS.

  13. Monitoring source in an unconscious plagiarism paradigm.

    Science.gov (United States)

    Landau, J D; Marsh, R L

    1997-06-01

    Current laboratory paradigms used to assess unconscious plagiarism consist of three tasks. First, participants generate solutions to a puzzle task with a partner (initial generation task); second, they recall their individual contribution (recall-own task); and third, they attempt to create new solutions that were not offered previously (generate-new task). An analysis of these tasks indicated that they differ in terms of the source monitoring they require. The two generative tasks require less differentiated information (e.g., familiarity) and relatively lax decision criteria. The recall-own task, however, demands more differentiated information and more extended decision criteria. In two experiments, factors known to influence source monitoring were manipulated. Consistent with the analysis, no effects were associated with the generative tasks. Recall-own plagiarisms increased when self- and other-generated solutions were difficult to distinguish (Experiment 1) and decreased when the two sources were easier to distinguish (Experiment 2).

  14. Development of micro pulse lidar system for atmospheric monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Hyung Ki; Song, Kyu Seok; Lee, Jong Min; Lee, Yong Ju; Kim, Duk Hyeon; Nam, Sung Mo; Go, Do Kyung; Yang, Gi Ho; Hong, Kyang He

    1999-12-01

    A compact small micro pulse lidar system is developed for atmospheric monitoring. The developed system can be operated during 24 hrs for four seasons. The maximum detection distance is 5 km at day time and 10 km at night. Specially, the problem of eye safety is solved by using diode pumped low pulse-energy Nd:YAG laser. Two rotational axis, vertical and horizontal, is chosen for 3D mapping of the atmospheric aerosol. The spatial resolution can be optionally changed from 5 m to 300 m, but time resolution which changes from several sec to several minutes depends on the detection distance and background signal. To analyze the obtained lidar signal, processing software is developed and applied to the lidar signal obtained near the chimney. Vertical lidar signal is also obtained and from this data we can find the thickness and change of cloud. (author)

  15. High current precision long pulse electron beam position monitor

    CERN Document Server

    Nelson, S D; Fessenden, T J; Holmes, C

    2000-01-01

    Precision high current long pulse electron beam position monitoring has typically experienced problems with high Q sensors, sensors damped to the point of lack of precision, or sensors that interact substantially with any beam halo thus obscuring the desired signal. As part of the effort to develop a multi-axis electron beam transport system using transverse electromagnetic stripline kicker technology, it is necessary to precisely determine the position and extent of long high energy beams for accurate beam position control (6 - 40 MeV, 1 - 4 kA, 2 μs beam pulse, sub millimeter beam position accuracy.) The kicker positioning system utilizes shot-to-shot adjustments for reduction of relatively slow (< 20 MHz) motion of the beam centroid. The electron beams passing through the diagnostic systems have the potential for large halo effects that tend to corrupt position measurements.

  16. 40 CFR 141.706 - Reporting source water monitoring results.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Reporting source water monitoring... Cryptosporidium Source Water Monitoring Requirements § 141.706 Reporting source water monitoring results. (a) Systems must report results from the source water monitoring required under § 141.701 no later than 10...

  17. Simple filtered repetitively pulsed vacuum arc plasma source

    Science.gov (United States)

    Chekh, Yu.; Zhirkov, I. S.; Delplancke-Ogletree, M. P.

    2010-02-01

    A very simple design of cathodic filtered vacuum arc plasma source is proposed. The source without filter has only four components and none of them require precise machining. The source operates in a repetitively pulsed regime, and for laboratory experiments it can be used without water cooling. Despite the simple construction, the source provides high ion current at the filter outlet reaching 2.5% of 400 A arc current, revealing stable operation in a wide pressure range from high vacuum to oxygen pressure up to more than 10-2 mbar. There is no need in complicated power supply system for this plasma source, only one power supply can be used to ignite the arc, to provide the current for the arc itself, to generate the magnetic field in the filter, and provide its positive electric biasing without any additional high power resistance.

  18. Overcoming High Energy Backgrounds at Pulsed Spallation Sources

    CERN Document Server

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

    2015-01-01

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

  19. The Strathclyde terahertz to optical pulse source (TOPS)

    CERN Document Server

    Jaroszynski, D A; Giraud, G; Jamison, S; Jones, D R; Issac, R C; McNeil, B M W; Phelps, A D R; Robb, G R M; Sandison, H; Vieux, G; Wiggins, S M; Wynne, K

    2000-01-01

    We describe the newly created free-electron laser facility situated at the University of Strathclyde in Scotland, which will produce ultra-short pulses of high-power electromagnetic radiation in the terahertz frequency range. The FEL will be based on a 4 MeV photoinjector producing picosecond 1 nC electron pulses and driven by a frequency tripled Ti:sapphire laser thus ensuring synchronism with conventional laser based tuneable sources. A synchronised multi-terawatt Ti:sapphire laser amplifier will be used in the study of laser/plasma/electron beam interactions and as a plasma based X-ray source. A substantial user commitment has already been made in support of the programme.

  20. Characteristics of the WNR: a pulsed spallation neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Russell, G.J.; Lisowski, P.W.; Howe, S.D.; King, N.S.P.; Meier, M.M.

    1982-01-01

    The Weapons Neutron Research facility (WNR) is a pulsed spallation neutron source in operation at the Los Alamos National Laboratory. The WNR uses part of the 800-MeV proton beam from the Clinton P. Anderson Meson Physics Facility accelerator. By choosing different target and moderator configurations and varying the proton pulse structure, the WNR can provide a white neutron source spanning the energy range from a few MeV to 800 MeV. The neutron spectrum from a bare target has been measured and is compared with predictions using an Intranuclear Cascade model coupled to a Monte Carlo transport code. Calculations and measurements of the neutronics of WNR target-moderator assemblies are presented.

  1. LMS Adaptive Filtering Applied to a Microwave Arterial Pulse Monitor

    Science.gov (United States)

    1988-12-01

    MIUTION NXTATEME A Approved for pubito r~ ehm DAprib hc"don U&tmod, 1 89 1. 7. 106 • + 5 : .. . . _ -.- + +’ .. d .. . 1 . . . .. . . AFIT/GE/ENG/88D-45...signals were low level and a certain degree of sensor repositioning was required to obtain a strong signal (greater than +/-0.2v). Once acquired...however, signal levels could be maintained at a fairly constant level even - after a slight movement of the pulse monitor. Region 3 exhibited a strong

  2. Pulsed ECR Source in Afterglow Operation at CERN

    CERN Document Server

    Hill, C E

    1995-01-01

    A pulsed 14 GHz ECR4 source, adapted to operate in the afterglow mode, was delivered by GANIL to CERN in the framework of the Heavy Ion Facility Project. After four months of operation to commission the facility, it completed its first operational run of nine weeks at the end of 1994, providing lead ions to nuclear physics and ion cooling experiments. A very stable beam, with a useful length of over 1 ms, of 80 emA of Pb27+ was provided by the source over this period. The operational problems experienced during the commissioning and operation, and the investigations to improve performance for the next experimental physics run are presented.

  3. Pulse wave transit time for monitoring respiration rate.

    Science.gov (United States)

    Johansson, A; Ahlstrom, C; Lanne, T; Ask, P

    2006-06-01

    In this study, we investigate the beat-to-beat respiratory fluctuations in pulse wave transit time (PTT) and its subcomponents, the cardiac pre-ejection period (PEP) and the vessel transit time (VTT) in ten healthy subjects. The three transit times were found to fluctuate in pace with respiration. When applying a simple breath detecting algorithm, 88% of the breaths seen in a respiration air-flow reference could be detected correctly in PTT. Corresponding numbers for PEP and VTT were 76 and 81%, respectively. The performance during hypo- and hypertension was investigated by invoking blood pressure changes. In these situations, the error rates in breath detection were significantly higher. PTT can be derived from signals already present in most standard monitoring set-ups. The transit time technology thus has prospects to become an interesting alternative for respiration rate monitoring.

  4. 5 MW pulsed spallation neutron source, Preconceptual design study

    Energy Technology Data Exchange (ETDEWEB)

    1994-06-01

    This report describes a self-consistent base line design for a 5 MW Pulsed Spallation Neutron Source (PSNS). It is intended to establish feasibility of design and as a basis for further expanded and detailed studies. It may also serve as a basis for establishing project cost (30% accuracy) in order to intercompare competing designs for a PSNS not only on the basis of technical feasibility and technical merit but also on the basis of projected total cost. The accelerator design considered here is based on the objective of a pulsed neutron source obtained by means of a pulsed proton beam with average beam power of 5 MW, in {approx} 1 {mu}sec pulses, operating at a repetition rate of 60 Hz. Two target stations are incorporated in the basic facility: one for operation at 10 Hz for long-wavelength instruments, and one operating at 50 Hz for instruments utilizing thermal neutrons. The design approach for the proton accelerator is to use a low energy linear accelerator (at 0.6 GeV), operating at 60 Hz, in tandem with two fast cycling booster synchrotrons (at 3.6 GeV), operating at 30 Hz. It is assumed here that considerations of cost and overall system reliability may favor the present design approach over the alternative approach pursued elsewhere, whereby use is made of a high energy linear accelerator in conjunction with a dc accumulation ring. With the knowledge that this alternative design is under active development, it was deliberately decided to favor here the low energy linac-fast cycling booster approach. Clearly, the present design, as developed here, must be carried to the full conceptual design stage in order to facilitate a meaningful technology and cost comparison with alternative designs.

  5. Laser Energy Monitor for Double-Pulsed 2-Micrometer IPDA Lidar Application

    Science.gov (United States)

    Refaat, Tamer F.; Petros, Mulugeta; Remus, Ruben; Yu, Jirong; Singh, Upendra N.

    2014-01-01

    Integrated path differential absorption (IPDA) lidar is a remote sensing technique for monitoring different atmospheric species. The technique relies on wavelength differentiation between strong and weak absorbing features normalized to the transmitted energy. 2-micron double-pulsed IPDA lidar is best suited for atmospheric carbon dioxide measurements. In such case, the transmitter produces two successive laser pulses separated by short interval (200 microseconds), with low repetition rate (10Hz). Conventional laser energy monitors, based on thermal detectors, are suitable for low repetition rate single pulse lasers. Due to the short pulse interval in double-pulsed lasers, thermal energy monitors underestimate the total transmitted energy. This leads to measurement biases and errors in double-pulsed IPDA technique. The design and calibration of a 2-micron double-pulse laser energy monitor is presented. The design is based on a high-speed, extended range InGaAs pin quantum detectors suitable for separating the two pulse events. Pulse integration is applied for converting the detected pulse power into energy. Results are compared to a photo-electro-magnetic (PEM) detector for impulse response verification. Calibration included comparing the three detection technologies in single-pulsed mode, then comparing the pin and PEM detectors in double-pulsed mode. Energy monitor linearity will be addressed.

  6. Pulsed rotating supersonic source used with merged molecular beams

    CERN Document Server

    Sheffield, L; Krasovitskiy, V; Rathnayaka, K D D; Lyuksyutov, I F; Herschbach, D R

    2012-01-01

    We describe a pulsed rotating supersonic beam source, evolved from an ancestral device [M. Gupta and D. Herschbach, J. Phys. Chem. A 105, 1626 (2001)]. The beam emerges from a nozzle near the tip of a hollow rotor which can be spun at high-speed to shift the molecular velocity distribution downward or upward over a wide range. Here we consider mostly the slowing mode. Introducing a pulsed gas inlet system, cryocooling, and a shutter gate eliminated the main handicap of the original device, in which continuous gas flow imposed high background pressure. The new version provides intense pulses, of duration 0.1-0.6 ms (depending on rotor speed) and containing ~10^12 molecules at lab speeds as low as 35 m/s and ~ 10^15 molecules at 400 m/s. Beams of any molecule available as a gas can be slowed (or speeded); e.g., we have produced slow and fast beams of rare gases, O2, Cl2, NO2, NH3, and SF6. For collision experiments, the ability to scan the beam speed by merely adjusting the rotor is especially advantageous when...

  7. Photoplethysmography beyond perfusion and oxygenation monitoring: Pulse wave analysis for hepatic graft monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Akl, Tony [Texas A& M University; Wilson, Mark A. [University of Pittsburgh School of Medicine, Pittsburgh PA; Ericson, Milton Nance [ORNL; Cote, Gerard L. [Texas A& M University

    2014-01-01

    Photoplethysmography is a widely used technique in monitoring perfusion and blood oxygen saturation by using the amplitude of the pulsatile signal on one or multiple wavelengths. However, the pulsatile signal carries in its waveform a substantial amount of information about the mechanical properties of the tissue and vasculature under investigation that is still yet to be utilized to its full potential. In this work, we present the feasibility of pulse wave analysis for the application of monitoring hepatic implants and diagnosing graft complications. In particular, we show the possibility of computing the slope of the pulse during the diastole phase to assess the location of vascular complications when they take place. This hypothesis was tested in a series of in vitro experiments using a PDMS based phantom mimicking the optical and mechanical properties of the portal vein. The emptying time of the vessel increased from 305 ms to 515 ms when an occlusion was induced downstream from the phantom. However, in the case of upstream occlusions, the emptying time remained constant. In both cases, a decrease in the amplitude of the pulse was recorded indicating the drop in flow levels. In addition, we show that quantifying the emptying time of the vasculature under investigation can be used to assess its compliance. The emptying time decreased from 305 ms for phantoms with compliance of 15 KPa to 195 ms for phantoms with compliance of 100 KPa. These compliance levels mimic those seen for normal and fibrotic hepatic tissue respectively.

  8. Vacuum Ultraviolet Xenon Excimer Light Source Excited by a Pulsed Jet Discharge

    National Research Council Canada - National Science Library

    Eiji FUTAGAMI; Toshiaki TAKADA; Junji KAWANAKA; Shoichi KUBODERA; Wataru SASAKI; Kou KUROSAWA; Kenichi MITSUHASHI; Tatsushi IGARASHI

    1995-01-01

      We have developed a new xenon excimer light source in vacuum ultraviolet (VUV). The use of a pulsed gas jet discharge realized efficient cluster excitation and spatially localized emission in VUV with an extremely long pulse duration...

  9. Note: A pulsed laser ion source for linear induction accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, H., E-mail: bamboobbu@hotmail.com [Institute of Fluid Physics, China Academy of Engineering Physics, P.O. Box 919-106, Mianyang 621900 (China); School of Physics, Peking University, Beijing 100871 (China); Zhang, K.; Shen, Y.; Jiang, X.; Dong, P.; Liu, Y.; Wang, Y.; Chen, D.; Pan, H.; Wang, W.; Jiang, W.; Long, J.; Xia, L.; Shi, J.; Zhang, L.; Deng, J. [Institute of Fluid Physics, China Academy of Engineering Physics, P.O. Box 919-106, Mianyang 621900 (China)

    2015-01-15

    We have developed a high-current laser ion source for induction accelerators. A copper target was irradiated by a frequency-quadrupled Nd:YAG laser (266 nm) with relatively low intensities of 10{sup 8} W/cm{sup 2}. The laser-produced plasma supplied a large number of Cu{sup +} ions (∼10{sup 12} ions/pulse) during several microseconds. Emission spectra of the plasma were observed and the calculated electron temperature was about 1 eV. An induction voltage adder extracted high-current ion beams over 0.5 A/cm{sup 2} from a plasma-prefilled gap. The normalized beam emittance measured by a pepper-pot method was smaller than 1 π mm mrad.

  10. Controlled Source Electromagnetic Monitoring of Hydraulic Fracturing

    Science.gov (United States)

    Couchman, M. J.; Everett, M. E.

    2016-12-01

    Controlled Source Electromagnetics (CSEM) have been used as a direct hydrocarbon indicator since the 1960s, with a resurgence in marine conventional settings in the new millennium, with many studies revolving around detecting a thin resistive layer such as a reservoir at 1m-3km depth. The presence of the resistive layer is characterized by a jump in electric field amplitude recorded at the boundary between the layer and the host sediments. Here the lessons learned from these studies are applied to terrestrial unconventional settings. However, unlike in marine settings where resistive hydrocarbon-charged fluids comprise a conventional reservoir, on land we are interested in electrically conductive injected fluids. The work shown here is a means to develop further methods to enable more reliable terrestrial CSEM monitoring of the flow of injected fluids associated with hydraulic fracturing of unconventional reservoirs and to detect subsurface fluids based on their CSEM signature and in turn, to infer the subsurface flow of electrically conductive injected fluids. Overall this project attempts to create more efficient fracturing, by determining fluid pathways, hence making projects more cost effective by reducing the cost of extraction. The predictive model developed focuses on the mapping of fluid flow in from a horizontal pipe in a uniform halfspace using a long in-line Horizontal Electric Dipole (HED) with electric field amplitude recorded by an array of electric field sensors. The code provided has been edited to include a long-dipole source in addition to the half dipole source originally in place in order to align with current CSEM field practices. The well casing has also been included due to its large effect on CSEM response.

  11. Measuring and monitoring KIPT Neutron Source Facility Reactivity

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Yan [Argonne National Lab. (ANL), Argonne, IL (United States); Gohar, Yousry [Argonne National Lab. (ANL), Argonne, IL (United States); Zhong, Zhaopeng [Argonne National Lab. (ANL), Argonne, IL (United States)

    2015-08-01

    Argonne National Laboratory (ANL) of USA and Kharkov Institute of Physics and Technology (KIPT) of Ukraine have been collaborating on developing and constructing a neutron source facility at Kharkov, Ukraine. The facility consists of an accelerator-driven subcritical system. The accelerator has a 100 kW electron beam using 100 MeV electrons. The subcritical assembly has keff less than 0.98. To ensure the safe operation of this neutron source facility, the reactivity of the subcritical core has to be accurately determined and continuously monitored. A technique which combines the area-ratio method and the flux-to-current ratio method is purposed to determine the reactivity of the KIPT subcritical assembly at various conditions. In particular, the area-ratio method can determine the absolute reactivity of the subcritical assembly in units of dollars by performing pulsed-neutron experiments. It provides reference reactivities for the flux-to-current ratio method to track and monitor the reactivity deviations from the reference state while the facility is at other operation modes. Monte Carlo simulations are performed to simulate both methods using the numerical model of the KIPT subcritical assembly. It is found that the reactivities obtained from both the area-ratio method and the flux-to-current ratio method are spatially dependent on the neutron detector locations and types. Numerical simulations also suggest optimal neutron detector locations to minimize the spatial effects in the flux-to-current ratio method. The spatial correction factors are calculated using Monte Carlo methods for both measuring methods at the selected neutron detector locations. Monte Carlo simulations are also performed to verify the accuracy of the flux-to-current ratio method in monitoring the reactivity swing during a fuel burnup cycle.

  12. Photoplethysmography beyond perfusion and oxygenation monitoring: pulse wave analysis for hepatic graft monitoring

    Science.gov (United States)

    Akl, Tony J.; Wilson, Mark A.; Ericson, M. Nance; Coté, Gerard L.

    2014-02-01

    Photoplethysmography is a technique widely used in monitoring perfusion and blood oxygen saturation based on the amplitude of the pulsatile signal at one or multiple wavelengths. However, the pulsatile signal carries in its waveform a substantial amount of information about the mechanical properties of the tissue and vasculature under investigation that is still yet to be utilized to its full potential. In this work, we present the feasibility of pulse wave analysis for the application of monitoring hepatic implants and diagnosing graft complications. In particular, we demonstrate the utility of computing the slope of the pulse during the diastole phase to assess compliance changes in tissue. This hypothesis was tested in a series of in vitro experiments using a polydimethylsiloxane based phantom mimicking the optical and mechanical properties of the portal vein. The emptying time decreased from 148.1 ms for phantoms with compliance of 12 KPa to 97.5 ms for phantoms with compliance of 61 KPa. These compliance levels mimic those seen for normal and fibrotic hepatic tissue respectively.

  13. X-Ray Scattering Applications Using Pulsed X-Ray Sources

    Energy Technology Data Exchange (ETDEWEB)

    Larson, B.C.

    1999-05-23

    Pulsed x-ray sources have been used in transient structural phenomena investigations for over fifty years; however, until the advent of synchrotrons sources and the development of table-top picosecond lasers, general access to ligh temporal resolution x-ray diffraction was relatively limited. Advances in diffraction techniques, sample excitation schemes, and detector systems, in addition to IncEased access to pulsed sources, have ld tO what is now a diverse and growing array of pulsed-source measurement applications. A survey of time-resolved investigations using pulsed x-ray sources is presented and research opportunities using both present and planned pulsed x-ray sources are discussed.

  14. A high current, short pulse electron source for wakefield accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Ho, Ching-Hung

    1992-12-31

    Design studies for the generation of a high current, short pulse electron source for the Argonne Wakefield Accelerator are presented. An L-band laser photocathode rf gun cavity is designed using the computer code URMEL to maximize the electric field on the cathode surface for fixed frequency and rf input power. A new technique using a curved incoming laser wavefront to minimize the space charge effect near the photocathode is studied. A preaccelerator with large iris to minimize wakefield effects is used to boost the drive beam to a useful energy of around 20 MeV for wakefield acceleration experiments. Focusing in the photocathode gun and the preaccelerator is accomplished with solenoids. Beam dynamics simulations throughout the preaccelerator are performed using particle simulation codes TBCI-SF and PARMELA. An example providing a useful set of operation parameters for the Argonne Wakefield Accelerator is given. The effects of the sagitta of the curved beam and laser amplitude and timing jitter effects are discussed. Measurement results of low rf power level bench tests and a high power test for the gun cavity are presented and discussed.

  15. A high current, short pulse electron source for wakefield accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Ho, Ching-Hung.

    1992-01-01

    Design studies for the generation of a high current, short pulse electron source for the Argonne Wakefield Accelerator are presented. An L-band laser photocathode rf gun cavity is designed using the computer code URMEL to maximize the electric field on the cathode surface for fixed frequency and rf input power. A new technique using a curved incoming laser wavefront to minimize the space charge effect near the photocathode is studied. A preaccelerator with large iris to minimize wakefield effects is used to boost the drive beam to a useful energy of around 20 MeV for wakefield acceleration experiments. Focusing in the photocathode gun and the preaccelerator is accomplished with solenoids. Beam dynamics simulations throughout the preaccelerator are performed using particle simulation codes TBCI-SF and PARMELA. An example providing a useful set of operation parameters for the Argonne Wakefield Accelerator is given. The effects of the sagitta of the curved beam and laser amplitude and timing jitter effects are discussed. Measurement results of low rf power level bench tests and a high power test for the gun cavity are presented and discussed.

  16. Non-Contact Cardiac Activity Monitoring using Pulsed Laser Vibrometer

    Directory of Open Access Journals (Sweden)

    Chen Chia WANG

    2014-01-01

    Full Text Available We demonstrate experimentally the detection of detailed human cardiac mechanical activity in a remote, non-contacting, and non-ionizing manner using a pulsed laser vibrometer. The highly sensitive pulsed laser vibrometer allows the detection of the temporally-phased mechanical events occurring in individual cardiac cycles even from the surface of clothing-covered extremities of the subjects. Fine structures of the detected cardiac traces are identified with their meanings assigned and corroborated using accelerometer and electrocardiogram measurements obtained concurrently with the pulsed laser vibrometer studies.

  17. PULSED ELECTROCHEMICAL TECHNIQUE FOR MONITORING ANTIBODY-ANTIGEN REACTIONS AT INTERFACES. (R825323)

    Science.gov (United States)

    AbstractThe mechanism of pulsed potential waveform for monitoring antibody¯antigen interactions at immunosensor interfaces is discussed. Some examples of antibody¯antigen interactions at quartz crystal microbalance and polymer-modified ...

  18. High Sensitivity Pulsed Laser Vibrometer for Aircraft Interior Noise Monitoring Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose an innovative pulsed laser vibrometer technology for the monitoring of interior noise inside an aircraft. The optical speckle-tolerant nature of the...

  19. Intense Pulsed Neutron Source progress report for 1991

    Energy Technology Data Exchange (ETDEWEB)

    Schriesheim, Alan

    1991-01-01

    The IPNS Progress Report 10th Anniversary Edition is being published in recognition of the first ten years of successful IPNS operation. To emphasize the significance of this milestone, we wanted this report to stand apart from the previous IPNS Progress Reports, and the best way to do this, we thought, was to make the design and organization of the report significantly different. In their articles, authors were asked to emphasize not only advances made since IPNS began operating but also the groundwork that was laid at its predecessor facilities - Argonne's ZING-P and ZING-P' prototype pulsed neutron sources and CP-5 reactor. Each article stands as a separate chapter in the report, since each represents a particular instrument or class of instruments, system, technique, or area of research. In some cases, contributions were similar to review articles in scientific journals, complete with extensive lists of references. Ten-year cumulative lists of members of IPNS committees and of scientists who have visited or done experiments at IPNS were assembled. A list of published and in press'' articles in journals, books, and conference proceedings, resulting from work done at IPNS during the past ten years, was compiled. And archival photographs of people and activities during the ten-year history of IPNS were located and were used liberally throughout the report. The titles of the chapters in this report are: accelerator; computer; radiation effects; powder; stress; single crystal; superconductivity; amorphous; small angle; reflection; quasielastic; inelastic; inelastic magnetic; deep inelastic; user program; the future; and publications.

  20. Intense Pulsed Neutron Source progress report for 1991

    Energy Technology Data Exchange (ETDEWEB)

    Schriesheim, Alan

    1991-01-01

    The IPNS Progress Report 10th Anniversary Edition is being published in recognition of the first ten years of successful IPNS operation. To emphasize the significance of this milestone, we wanted this report to stand apart from the previous IPNS Progress Reports, and the best way to do this, we thought, was to make the design and organization of the report significantly different. In their articles, authors were asked to emphasize not only advances made since IPNS began operating but also the groundwork that was laid at its predecessor facilities - Argonne's ZING-P and ZING-P' prototype pulsed neutron sources and CP-5 reactor. Each article stands as a separate chapter in the report, since each represents a particular instrument or class of instruments, system, technique, or area of research. In some cases, contributions were similar to review articles in scientific journals, complete with extensive lists of references. Ten-year cumulative lists of members of IPNS committees and of scientists who have visited or done experiments at IPNS were assembled. A list of published and in press'' articles in journals, books, and conference proceedings, resulting from work done at IPNS during the past ten years, was compiled. And archival photographs of people and activities during the ten-year history of IPNS were located and were used liberally throughout the report. The titles of the chapters in this report are: accelerator; computer; radiation effects; powder; stress; single crystal; superconductivity; amorphous; small angle; reflection; quasielastic; inelastic; inelastic magnetic; deep inelastic; user program; the future; and publications.

  1. Intense Pulsed Neutron Source progress report for 1991

    Energy Technology Data Exchange (ETDEWEB)

    1991-12-31

    The IPNS Progress Report 10th Anniversary Edition is being published in recognition of the first ten years of successful IPNS operation. To emphasize the significance of this milestone, we wanted this report to stand apart from the previous IPNS Progress Reports, and the best way to do this, we thought, was to make the design and organization of the report significantly different. In their articles, authors were asked to emphasize not only advances made since IPNS began operating but also the groundwork that was laid at its predecessor facilities - Argonne`s ZING-P and ZING-P` prototype pulsed neutron sources and CP-5 reactor. Each article stands as a separate chapter in the report, since each represents a particular instrument or class of instruments, system, technique, or area of research. In some cases, contributions were similar to review articles in scientific journals, complete with extensive lists of references. Ten-year cumulative lists of members of IPNS committees and of scientists who have visited or done experiments at IPNS were assembled. A list of published and ``in press`` articles in journals, books, and conference proceedings, resulting from work done at IPNS during the past ten years, was compiled. And archival photographs of people and activities during the ten-year history of IPNS were located and were used liberally throughout the report. The titles of the chapters in this report are: accelerator; computer; radiation effects; powder; stress; single crystal; superconductivity; amorphous; small angle; reflection; quasielastic; inelastic; inelastic magnetic; deep inelastic; user program; the future; and publications.

  2. Pulse properties of terrestrial gamma-ray flashes detected by the Fermi Gamma-Ray Burst Monitor

    CERN Document Server

    Foley, Suzanne; Briggs, Michael S; Connaughton, Valerie; Tierney, David; McBreen, Sheila; Dwyer, Joseph; Chaplin, Vandiver L; Bhat, P Narayana; Byrne, David; Cramer, Eric; Fishman, Gerald J; Xiong, Shaolin; Greiner, Jochen; Kippen, R Marc; Meegan, Charles A; Paciesas, William S; Preece, Robert D; von Kienlin, Andreas; Wilson-Hodge, Colleen

    2015-01-01

    The Gamma-ray Burst Monitor (GBM) on board the Fermi Gamma-ray Space Telescope has triggered on over 300 terrestrial gamma-ray flashes (TGFs) since its launch in June 2008. With 14 detectors, GBM collects on average ~100 counts per triggered TGF, enabling unprecedented studies of the time profiles of TGFs. Here we present the first rigorous analysis of the temporal properties of a large sample of TGFs (278), including the distributions of the rise and fall times of the individual pulses and their durations. A variety of time profiles are observed with 19 of TGFs having multiple pulses separated in time and 31 clear cases of partially overlapping pulses. The effect of instrumental dead time and pulse pileup on the temporal properties are also presented. As the observed gamma ray pulse structure is representative of the electron flux at the source, TGF pulse parameters are critical to distinguish between relativistic feedback discharge and lightning leader models. We show that at least 67% of TGFs at satellite ...

  3. Swift/BAT monitoring of Fermi/LAT sources

    CERN Document Server

    Krimm, Hans A; Gehrels, Neil; Tueller, Jack; Baumgartner, Wayne H; Cummings, Jay R; Sakamoto, Taka; Fenimore, Edward E; Palmer, David M; Markwardt, Craig B; Skinner, Gerald K; Stamatikos, Michael

    2009-01-01

    The Swift Burst Alert Telescope (BAT) hard X-ray transient monitor tracks more than 700 galactic and extragalactic sources on time scales ranging from a single Swift pointing (approximately 20 minutes) to one day. The monitored sources include all objects from the Fermi LAT bright source list which are either identified or which have a 95% error confidence radius of less than eight arc minutes. We report on the detection statistics of these sources in the BAT monitor both before and after the launch of Fermi.

  4. Validation of pulse oximetry for monitoring of hypoxaemic episodes in the late postoperative period

    DEFF Research Database (Denmark)

    Stausholm, K; Rosenberg-Adamsen, S; Edvardsen, L;

    1997-01-01

    We monitored 12 patients undergoing major abdominal surgery using a pulse oximeter (Nellcor N-200) and a transcutaneous oxygen tension monitor (TINA, Radiometer A/S) on the second or third night after operation. Of the shortest hypoxaemic episodes measured with the pulse oximeter (... duration), 78% also occurred in the transcutaneous oxygen tension measurement. Episodes of longer duration (> or = 1 min duration on the pulse oximeter) were, in 95% of cases, reflected in the transcutaneous oxygen tension measurement also. Thus postoperative episodic desaturations lasting > or = 1 min...

  5. The Radiation Dose Determination of the Pulsed X-ray Source

    Science.gov (United States)

    Miloichikova, I.; Stuchebrov, S.; Zhaksybayeva, G.; Wagner, A.

    2014-10-01

    In this paper the radiation dose measurement technique of the pulsed X-ray source RAP-160-5 is described. The dose rate measurement results from the pulsed X-ray beams at the different distance between the pulsed X-ray source focus and the detector obtained with the help of the thermoluminescent detectors DTL-02, the universal dosimeter UNIDOS E equipped with the plane-parallel ionization chamber type 23342, the dosimeter-radiometer DKS-96 and the radiation dosimeter AT 1123 are demonstrated. The recommendations for the dosimetry measurements of the pulsed X-ray generator RAP-160-5 under different radiation conditions are proposed.

  6. Demonstration of fiber pulsed light source at 1.6 μm with adjustable pulse duration

    Institute of Scientific and Technical Information of China (English)

    Xue Feng; Lei Zhang; Xiaoming Liu

    2007-01-01

    A novel practical 1.66-μm pulse light source with adjustable pulse duration is proposed. A 2.5-km Raman fiber is placed into a ring type Q-switched erbium-doped fiber laser (Q-EDFL), serving as both delay line fiber and Raman gain medium so that in addition to the wavelength shifted to 1.6μm, the pulse duration and the buildup time can be relatively extended. By properly controlling the fall edge of the acousto-optic switch (AOS), the pulse duration of 30-345 ns for ~ 770-Hz repetition frequency with power of 1-1.6 W is achieved.

  7. On the limit of neutron fluxes in the fission-based pulsed neutron sources

    Science.gov (United States)

    Aksenov, V. L.; Ananiev, V. D.; Komyshev, G. G.; Rogov, A. D.; Shabalin, E. P.

    2017-09-01

    The upper limit of the density of the thermal neutron flux from pulsed sources based on the fission reaction is established. Three types of sources for research on ejected beams are considered: a multiplying target of the proton accelerator (a booster), a booster with the reactivity modulation (a superbooster), and a pulsing reactor. Comparison with other high-flux sources is carried out. The investigation has been performed at the Frank Laboratory of Neutron Physics of JINR.

  8. Variations in physician interpretation of overnight pulse oximetry monitoring.

    Science.gov (United States)

    Ramsey, Rory; Mehra, Reena; Strohl, Kingman P

    2007-09-01

    Overnight pulse oximetry is commonly used for hypoxemia evaluation in patients with COPD and sleep-disordered breathing. There is little information regarding its impact on physician decision making, and therefore an important measure of its clinical utility is untested and unknown. The aim of this study was to describe physician interpretation, use, and opinions regarding overnight pulse oximetry. Forty-one pulmonary physicians and fellows participated in structured interviews consisting of three oximetry record interpretations, oral responses to a standard question set, and a questionnaire. Qualitative data were analyzed using an open coding process. Quantitative data were assessed for distributions. Four measures were consistently used by the majority of physicians in record interpretation: background information, arterial oxygen saturation measured by pulse oximetry (Spo(2)) waveform and pattern, and time spent with Spo(2) 60% consensus. There was a wide range of opinions on important matters related to this test, including test utility, indications, variables considered most important for interpretation, and criteria for nocturnal oxygen prescription. Forty-one physicians provided 35 different opinions on when nocturnal supplemental oxygen should be initiated. The variation in physician interpretation, use, and opinions regarding overnight pulse oximetry calls into question its clinical utility and underscores a need for standardization of presentation, training, and interpretation.

  9. Patient Blood Pressure and Pulse Rate Monitoring With an Alert ...

    African Journals Online (AJOL)

    2012-12-01

    Dec 1, 2012 ... Blood pressure and pulse rate are two of the vital signs of humans and it is ... even from their homes and transfer the readings into the computer ... benefits from Omron's 'IntelliSense' .... (the port number assigned to the smart.

  10. Proceedings of the workshop on ion source issues relevant to a pulsed spallation neutron source: Part 2 workshop presentations

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, L.; Leung, Ka-Ngo; Alonso, J. [eds.

    1994-10-01

    As part of the Lawrence Berkeley Laboratory Pulsed Spallation Source study, this Workshop was convened to address ion-source technology`s present status with respect to the next-generation Pulsed Spallation Source in the 1-5 MW range for the neutron scattering community. Considerations of Low Energy Beam Transport (LEBT) parameters and designs were included in the discussions throughout the Workshop. Ion-source requirements and actually-achieved performances were assessed, resulting in a determination of research and development requirements to bridge the gap. Part 1 of these Proceedings summarizes the Workshop; Part 2 contains viewgraphs of Workshop presentations.

  11. Wrist Pulse Rate Monitor Using Self-Injection-Locked Radar Technology

    Directory of Open Access Journals (Sweden)

    Fu-Kang Wang

    2016-10-01

    Full Text Available To achieve sensitivity, comfort, and durability in vital sign monitoring, this study explores the use of radar technologies in wearable devices. The study first detected the respiratory rates and heart rates of a subject at a one-meter distance using a self-injection-locked (SIL radar and a conventional continuous-wave (CW radar to compare the sensitivity versus power consumption between the two radars. Then, a pulse rate monitor was constructed based on a bistatic SIL radar architecture. This monitor uses an active antenna that is composed of a SIL oscillator (SILO and a patch antenna. When attached to a band worn on the subject’s wrist, the active antenna can monitor the pulse on the subject’s wrist by modulating the SILO with the associated Doppler signal. Subsequently, the SILO’s output signal is received and demodulated by a remote frequency discriminator to obtain the pulse rate information.

  12. Wrist Pulse Rate Monitor Using Self-Injection-Locked Radar Technology.

    Science.gov (United States)

    Wang, Fu-Kang; Tang, Mu-Cyun; Su, Sheng-Chao; Horng, Tzyy-Sheng

    2016-10-26

    To achieve sensitivity, comfort, and durability in vital sign monitoring, this study explores the use of radar technologies in wearable devices. The study first detected the respiratory rates and heart rates of a subject at a one-meter distance using a self-injection-locked (SIL) radar and a conventional continuous-wave (CW) radar to compare the sensitivity versus power consumption between the two radars. Then, a pulse rate monitor was constructed based on a bistatic SIL radar architecture. This monitor uses an active antenna that is composed of a SIL oscillator (SILO) and a patch antenna. When attached to a band worn on the subject's wrist, the active antenna can monitor the pulse on the subject's wrist by modulating the SILO with the associated Doppler signal. Subsequently, the SILO's output signal is received and demodulated by a remote frequency discriminator to obtain the pulse rate information.

  13. Fast pulsed operation of a small non-radioactive electron source with continuous emission current control.

    Science.gov (United States)

    Cochems, P; Kirk, A T; Bunert, E; Runge, M; Goncalves, P; Zimmermann, S

    2015-06-01

    Non-radioactive electron sources are of great interest in any application requiring the emission of electrons at atmospheric pressure, as they offer better control over emission parameters than radioactive electron sources and are not subject to legal restrictions. Recently, we published a simple electron source consisting only of a vacuum housing, a filament, and a single control grid. In this paper, we present improved control electronics that utilize this control grid in order to focus and defocus the electron beam, thus pulsing the electron emission at atmospheric pressure. This allows short emission pulses and excellent stability of the emitted electron current due to continuous control, both during pulsed and continuous operations. As an application example, this electron source is coupled to an ion mobility spectrometer. Here, the pulsed electron source allows experiments on gas phase ion chemistry (e.g., ion generation and recombination kinetics) and can even remove the need for a traditional ion shutter.

  14. Advanced Pulse Width Technique in Impedance Source Cascaded Multilevel Inverter with Asymmetric Topology

    Directory of Open Access Journals (Sweden)

    Rajnish Kumar Sharma

    2016-08-01

    Full Text Available In this research, a single phase Z-source cascading Multilevel Inverter, Nine-level inverter topologies with a trinary DC sources are offered. The recommended topologies are expanded by cascading a full bridge inverter with dissimilar DC sources. This paper recommends advanced pulse with modulation technique as a switching scheme. In this PWM technology, trapezoidal modulation technique is used as variable amplitude pulse width modulation. These topologies compromise reduced harmonics present in the output voltage and superior root mean square (RMS values of the output voltages linked with the traditional trapezoidal pulse width modulation. The simulation of proposed circuit is carried out by using MATLAB/SIMULINK.

  15. A 20 kV, 5 A, 1 ns Risetime Pulsed Electron Beam Source

    Institute of Scientific and Technical Information of China (English)

    Chen Yulan; Zeng Zhengzhong; Wang Haiyang; Ma Lianying

    2005-01-01

    A 20 kV, 1 ns risetime pulsed electron beam source was developed using an extremely small gap (0.1 mm) diode driven by a sub-nanosecond risetime, 10 kV rectangular pulse generator. A beam current of 5 A was detected by using a fast response Faraday cup at a distance of 2 cm away from a grid anode. The shot to shot variation of the electron beam pulse was less than 10%.

  16. Solid-State Source of Subcycle Pulses in the Midinfrared.

    Science.gov (United States)

    Stepanov, E A; Lanin, A A; Voronin, A A; Fedotov, A B; Zheltikov, A M

    2016-07-22

    We demonstrate a robust, all-solid-state approach for the generation of microjoule subcycle pulses in the midinfrared through a cascade of carefully optimized parametric-amplification, difference-frequency-generation, spectral-broadening, and chirp-compensation stages. This method of subcycle waveform generation becomes possible due to an unusual, ionization-assisted solid-state pulse self-compression dynamics, where highly efficient spectral broadening is enabled by ultrabroadband four-wave parametric amplification phase matched near the zero-group-velocity wavelength of the material.

  17. A Fast Pulsed Neutron Source for Time-of-Flight Detection of Nuclear Materials and Explosives

    Science.gov (United States)

    Krishnan, Mahadevan; Bures, Brian; James, Colt; Madden, Robert; Hennig, Wolfgang; Breus, Dimitry; Asztalos, Stephen; Sabourov, Konstantin; Lane, Stephen

    2011-12-01

    AASC has built a fast pulsed neutron source based on the Dense Plasma Focus (DPF). The more current version stores only 100 J but fires at ˜10-50 Hz and emits ˜106n/pulse at a peak current of 100 kA. Both sources emit 2.45±0.1 MeV (DD) neutron pulses of ˜25-40 ns width. Such fast, quasi-monoenergetic pulses allow time-of-flight detection of characteristic emissions from nuclear materials or high explosives. A test is described in which iron targets were placed at different distances from the point neutron source. Detectors such as Stilbene and LaBr3 were used to capture inelastically induced, 847 keV gammas from the iron target. Shielding of the source and detectors eliminated most (but not all) of the source neutrons from the detectors. Gated detection, pulse shape analysis and time-of-flight discrimination enable separation of gamma and neutron signatures and localization of the target. A Monte Carlo simulation allows evaluation of the potential of such a fast pulsed source for a field-portable detection system. The high rep-rate source occupies two 200 liter drums and uses a cooled DPF Head that is <500 cm3 in volume.

  18. A Fast Pulsed Neutron Source for Time-of-Flight Detection of Nuclear Materials and Explosives

    Energy Technology Data Exchange (ETDEWEB)

    Krishnan, Mahadevan; Bures, Brian; James, Colt; Madden, Robert [Alameda Applied Sciences Corporation, 3077 Teagarden Street, San Leandro, CA 94577 (United States); Hennig, Wolfgang; Breus, Dimitry; Asztalos, Stephen; Sabourov, Konstantin [XIA LLC, 31057 Genstar Road, Hayward, CA 94544 (United States); Lane, Stephen [NSF Center for Biophotonics and School of Medicine, University of California Davis, Sacramento CA, 95817 (United States)

    2011-12-13

    AASC has built a fast pulsed neutron source based on the Dense Plasma Focus (DPF). The more current version stores only 100 J but fires at {approx}10-50 Hz and emits {approx}10{sup 6}n/pulse at a peak current of 100 kA. Both sources emit 2.45{+-}0.1 MeV(DD) neutron pulses of {approx}25-40 ns width. Such fast, quasi-monoenergetic pulses allow time-of-flight detection of characteristic emissions from nuclear materials or high explosives. A test is described in which iron targets were placed at different distances from the point neutron source. Detectors such as Stilbene and LaBr3 were used to capture inelastically induced, 847 keV gammas from the iron target. Shielding of the source and detectors eliminated most (but not all) of the source neutrons from the detectors. Gated detection, pulse shape analysis and time-of-flight discrimination enable separation of gamma and neutron signatures and localization of the target. A Monte Carlo simulation allows evaluation of the potential of such a fast pulsed source for a field-portable detection system. The high rep-rate source occupies two 200 liter drums and uses a cooled DPF Head that is <500 cm{sup 3} in volume.

  19. An Electronic Patch for Wearable Health Monitoring by Reflectance Pulse Oximetry

    DEFF Research Database (Denmark)

    Haahr, Rasmus Grønbek; Duun, Sune Bro; Toft, Mette H.;

    2012-01-01

    We report the development of an Electronic Patch for wearable health monitoring. The Electronic Patch is a new health monitoring system incorporating biomedical sensors, microelectronics, radio frequency (RF) communication, and a battery embedded in a 3-dimensional hydrocolloid polymer...... photodiode to enable low power consumption by the light emitting components. The Electronic Patch has a disposable part of soft adhesive hydrocolloid polymer and a reusable part of hard polylaurinlactam. The disposable part contains the battery. The reusable part contains the reflectance pulse oximetry....... In this paper the Electronic Patch is demonstrated with a new optical biomedical sensor for reflectance pulse oximetry so that the Electronic Patch in this case can measure the pulse and the oxygen saturation. The reflectance pulse oximetry solution is based on a recently developed annular backside silicon...

  20. Pulsed, Single-Frequency, 2-um Seed Source for Coherent LIDAR Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The primary objective of the proposed Phase I effort is to develop and demonstrate a low-average power, pulsed, single-frequency, 2-um Ho-laser source for...

  1. Short X-ray pulses from third-generation light sources.

    Science.gov (United States)

    Stepanov, A G; Hauri, C P

    2016-01-01

    High-brightness X-ray radiation produced by third-generation synchrotron light sources (TGLS) has been used for numerous time-resolved investigations in many different scientific fields. The typical time duration of X-ray pulses delivered by these large-scale machines is about 50-100 ps. A growing number of time-resolved studies would benefit from X-ray pulses with two or three orders of magnitude shorter duration. Here, techniques explored in the past for shorter X-ray pulse emission at TGLS are reviewed and the perspective towards the realisation of picosecond and sub-picosecond X-ray pulses are discussed.

  2. All-Sky Monitoring of Variable Sources with Fermi GBM

    Science.gov (United States)

    Wilson-Hodge, Colleen A.; Cherry, Michael L.; Case, Gary L.; Camero-Arranz, Ascension; Chaplin, Vandiver; Connaughton, Valerie; Finger, Mark H.; Jenke, Pater; Rodi, James C.; Baumgartner, Wayne H.; Beklen, Elif; Bhat, P. Narayana; Briggs, Michael S.; Gehrels, Neil; Greiner, Jochen; Jahoda, Keith; Kippen, R. Marc; Kouveliotou, Chryssa; Krimm, Hans A.; Kuulkers, Erik; Lund, Niels; Meegan, Charles A.; Natalucci, Lorenzo; Paciesas, William S.; Preece, Robert

    2011-01-01

    This slide presentation reviews the monitoring of variable sources with the Fermi Gamma Ray Burst Monitor (GBM). It reviews the use of the Earth Occultation technique, the observations of the Crab Nebula with the GBM, and the comparison with other satellite's observations. The instruments on board the four satellites indicate a decline in the Crab from 2008-2010.

  3. Global biodiversity monitoring: from data sources to essential biodiversity variables

    Science.gov (United States)

    Proenca, Vania; Martin, Laura J.; Pereira, Henrique M.; Fernandez, Miguel; McRae, Louise; Belnap, Jayne; Böhm, Monika; Brummitt, Neil; Garcia-Moreno, Jaime; Gregory, Richard D.; Honrado, Joao P; Jürgens, Norbert; Opige, Michael; Schmeller, Dirk S.; Tiago, Patricia; van Sway, Chris A

    2016-01-01

    Essential Biodiversity Variables (EBVs) consolidate information from varied biodiversity observation sources. Here we demonstrate the links between data sources, EBVs and indicators and discuss how different sources of biodiversity observations can be harnessed to inform EBVs. We classify sources of primary observations into four types: extensive and intensive monitoring schemes, ecological field studies and satellite remote sensing. We characterize their geographic, taxonomic and temporal coverage. Ecological field studies and intensive monitoring schemes inform a wide range of EBVs, but the former tend to deliver short-term data, while the geographic coverage of the latter is limited. In contrast, extensive monitoring schemes mostly inform the population abundance EBV, but deliver long-term data across an extensive network of sites. Satellite remote sensing is particularly suited to providing information on ecosystem function and structure EBVs. Biases behind data sources may affect the representativeness of global biodiversity datasets. To improve them, researchers must assess data sources and then develop strategies to compensate for identified gaps. We draw on the population abundance dataset informing the Living Planet Index (LPI) to illustrate the effects of data sources on EBV representativeness. We find that long-term monitoring schemes informing the LPI are still scarce outside of Europe and North America and that ecological field studies play a key role in covering that gap. Achieving representative EBV datasets will depend both on the ability to integrate available data, through data harmonization and modeling efforts, and on the establishment of new monitoring programs to address critical data gaps.

  4. COMPLIS: COllinear spectroscopy Measurements using a Pulsed Laser Ion Source

    CERN Multimedia

    2002-01-01

    A Pulsed Laser spectroscopy experiment has been installed for the study of hyperfine structure and isotope shift of refractory and daughter elements from ISOLDE beams. It includes decelerated ion-implantation, element-selective laser ionization, magnetic and time-of-flight mass separation. The laser spectroscopy has been performed on the desorbed atoms in a set-up at ISOLDE-3 but later on high resolution laser collinear spectroscopy with the secondary pulsed ion beam is planned for the Booster ISOLDE set-up. During the first operation time of ISOLDE-3 we restricted our experiments to Doppler-limited resonant ionization laser and $\\gamma$-$\\gamma$ nuclear spectroscopy on neutron deficient platinum isotopes of even mass number down to A~=~186 and A~=~179 respectively. These isotopes have been produced by implantation of radioactive Hg and their subsequent $\\beta$-decay.

  5. High on/off ratio ns laser pulses for a triggered single-photon source

    CERN Document Server

    Jin, Gang; He, Jun; Wang, Junmin

    2016-01-01

    852nm nano-second laser pulse chain with a high on/off ratio is generated via chopping a continuous-wave laser beam by using of a Mach-Zehnder-type electro-optic intensity modulator (MZ-EOIM). Detailed analysis and dependence of the on/off ratio on the splitting ratio, the co-splitting ratio, and the arms loss of MZ-EIOM are presented. By optimizing the polarization of incident laser beam and stabilizing MZ-EOIM temperature, the static on/off ratio of 12600:1 is achieved. Also the dynamic on/off ratios versus the pulse repetition rate and the pulse duty cycle are measured and discussed. This high on/off ratio ns pulsed laser system has served as the excitation pulse source for a triggered single-photon source based on trapped single cesium atom, which reveals a representative anti-bunching.

  6. Pulsed voltage electrospray ion source and method for preventing analyte electrolysis

    Science.gov (United States)

    Kertesz, Vilmos; Van Berkel, Gary

    2011-12-27

    An electrospray ion source and method of operation includes the application of pulsed voltage to prevent electrolysis of analytes with a low electrochemical potential. The electrospray ion source can include an emitter, a counter electrode, and a power supply. The emitter can include a liquid conduit, a primary working electrode having a liquid contacting surface, and a spray tip, where the liquid conduit and the working electrode are in liquid communication. The counter electrode can be proximate to, but separated from, the spray tip. The power system can supply voltage to the working electrode in the form of a pulse wave, where the pulse wave oscillates between at least an energized voltage and a relaxation voltage. The relaxation duration of the relaxation voltage can range from 1 millisecond to 35 milliseconds. The pulse duration of the energized voltage can be less than 1 millisecond and the frequency of the pulse wave can range from 30 to 800 Hz.

  7. 3D sensor for indirect ranging with pulsed laser source

    Science.gov (United States)

    Bronzi, D.; Bellisai, S.; Villa, F.; Scarcella, C.; Bahgat Shehata, A.; Tosi, A.; Padovini, G.; Zappa, F.; Tisa, S.; Durini, D.; Weyers, S.; Brockherde, W.

    2012-10-01

    The growing interest for fast, compact and cost-effective 3D ranging imagers for automotive applications has prompted to explore many different techniques for 3D imaging and to develop new system for this propose. CMOS imagers that exploit phase-resolved techniques provide accurate 3D ranging with no complex optics and are rugged and costeffective. Phase-resolved techniques indirectly measure the round-trip return of the light emitted by a laser and backscattered from a distant target, computing the phase delay between the modulated light and the detected signal. Singlephoton detectors, with their high sensitivity, allow to actively illuminate the scene with a low power excitation (less than 10W with diffused daylight illumination). We report on a 4x4 array of CMOS SPAD (Single Photon Avalanche Diodes) designed in a high-voltage 0.35 μm CMOS technology, for pulsed modulation, in which each pixel computes the phase difference between the laser and the reflected pulse. Each pixel comprises a high-performance 30 μm diameter SPAD, an analog quenching circuit, two 9 bit up-down counters and memories to store data during the readout. The first counter counts the photons detected by the SPAD in a time window synchronous with the laser pulse and integrates the whole echoed signal. The second counter accumulates the number of photon detected in a window shifted with respect to the laser pulse, and acquires only a portion of the reflected signal. The array is readout with a global shutter architecture, using a 100 MHz clock; the maximal frame rate is 3 Mframe/s.

  8. 10 GHz pulse source for 640 Gbit/s OTDM based on phase modulator and self-phase modulation

    DEFF Research Database (Denmark)

    Hu, Hao; Mulvad, Hans Christian Hansen; Peucheret, Christophe

    2011-01-01

    to compensate the chirp. The non-linear pulse compression stages are based on self-phase modulation (SPM) in dispersion-flattened highly non-linear fibers (DF-HNLF). The pulse source is tunable over the C-band with negligible pedestal. © 2011 Optical Society of America....... the high pulse quality. The pulse source is based on a linear pulse compression stage followed by two polarization-independent non-linear pulse compression stages. The linear pulse compression stage relies on a phase modulator, which is used to generate linear chirp and followed by a dispersive element...

  9. A Dual-Mode UWB Wireless Platform with Random Pulse Length Detection for Remote Patient Monitoring

    DEFF Research Database (Denmark)

    Reyes, Carlos; Bisbe, Sergi; Shen, Ming

    2013-01-01

    on a single hardware platform, but it is capable of both monitoring and data transmission. This is achieved by employing a new random pulse length detection method that allows data transmission by using a modulated monitoring signal. To prove the proposed concept a test system has been built, using commercial......This paper presents a dual-mode ultra-wideband platform for wireless Remote Patient Monitoring (RPM). Existing RPM solutions are typically based on two different hardware platforms; one responsible for medical-data monitoring and one to handle data transmission. The proposed RPM topology is based...

  10. Pulsed, Inductively Generated, Streaming Plasma Ion Source for Heavy Ion Fusion Linacs

    Energy Technology Data Exchange (ETDEWEB)

    Steven C. Glidden; Howard D Sanders; John B. Greenly; Daniel L. Dongwoo

    2006-04-28

    This report describes a compact, high current density, pulsed ion source, based on electrodeless, inductively driven gas breakdown, developed to meet the requirements on normalized emittance, current density, uniformity and pulse duration for an ion injector in a heavy-ion fusion driver. The plasma source produces >10 μs pulse of Argon plasma with ion current densities >100 mA/cm2 at 30 cm from the source and with strongly axially directed ion energy of about 80 eV, and sub-eV transverse temperature. The source has good reproducibility and spatial uniformity. Control of the current density during the pulse has been demonstrated with a novel modulator coil method which allows attenuation of the ion current density without significantly affecting the beam quality. This project was carried out in two phases. Phase 1 used source configurations adapted from light ion sources to demonstrate the feasibility of the concept. In Phase 2 the performance of the source was enhanced and quantified in greater detail, a modulator for controlling the pulse shape was developed, and experiments were conducted with the ions accelerated to >40 kV.

  11. Report on the international workshop on cold moderators for pulsed neutron sources.

    Energy Technology Data Exchange (ETDEWEB)

    Carpenter, J. M.

    1999-01-06

    The International Workshop on Cold Moderators for Pulsed Neutron Sources resulted from the coincidence of two forces. Our sponsors in the Materials Sciences Branch of DOE's Office of Energy Research and the community of moderator and neutron facility developers both realized that it was time. The Neutron Sources Working Group of the Megascience Forum of the Organization for Economic Cooperation and Development offered to contribute its support by publishing the proceedings, which with DOE and Argonne sponsorship cemented the initiative. The purposes of the workshop were: to recall and improve the theoretical groundwork of time-dependent neutron thermalization; to pose and examine the needs for and benefits of cold moderators for neutron scattering and other applications of pulsed neutron sources; to summarize experience with pulsed source, cold moderators, their performance, effectiveness, successes, problems and solutions, and the needs for operational data; to compile and evaluate new ideas for cold moderator materials and geometries; to review methods of measuring and characterizing pulsed source cold moderator performance; to appraise methods of calculating needed source characteristics and to evaluate the needs and prospects for improvements; to assess the state of knowledge of data needed for calculating the neutronic and engineering performance of cold moderators; and to outline the needs for facilities for testing various aspects of pulsed source cold moderator performance.

  12. Generating Picosecond X-Ray Pulses with Beam Manipulation in Synchrotron Light Sources

    CERN Document Server

    Guo, Weiming; Harkay, Katherine C; Sajaev, Vadim; Yang Bing Xin

    2005-01-01

    The length of x-ray pulses generated by storage ring light sources is usually tens of picoseconds. For example, the value is 40 ps rms at the Advanced Photon Source (APS). Methods of x-ray pulse compression are of great interest at the APS. One possible method, per Zholents et al., is to tilt the electron bunch with deflecting rf cavities.* Alternately, we found that the electron bunch can develop a tilt after application of a vertical kick in the presence of nonzero chromaticity. After slicing, the x-ray pulse length is determined by the tilt angle and the vertical beam size. In principal, sub-picosecond pulses can be obtained at APS. To date we have observed 6 ps rms visible light pulses with a streak camera. Efforts are underway to attempt further compression of the x-ray pulse and to increase the brilliance. This method can be easily applied to any storage ring light sources to generate x-ray pulses up to two orders of magnitude shorter than the electron bunch length. In this paper, we will present the th...

  13. IOT RF Power Sources for Pulsed and CW Linacs

    CERN Document Server

    Bohlen, H P

    2004-01-01

    For many years, klystrons have been the preferred RF power amplifiers for both pulsed and CW linacs at UHF and higher frequencies. Their properties have earned them that position. But in recent years in UHF terrestrial television transmitters the earlier predominant klystron has been replaced the Inductive Output Tube (IOT) because the IOT provides higher efficiency and, due to its excellent linearity, can handle the simultaneous amplification of both the vision and the sound signal. Its robustness and life expectancy equals that of a klystron, and it more than compensates its lower gain by a lower price and a smaller size. For linac operation, derivates of UHF TV IOTs, capable of up to 80 kW CW output power, are already available and operating. In L-Band, they are presently joined by recently developed 15 to 30 kW CW IOTs. HOM-IOTs are expected to extend the CW range in UHF to 1 MW and beyond. Pulsed operation of an IOT can be achieved without a high-voltage modulator. Since the beam current is grid-controll...

  14. A short pulse, high rep-rate microdischarge VUV source

    Science.gov (United States)

    Stephens, Jacob; Fierro, Andrew; Dickens, James; Neuber, Andreas; CenterPulsed Power; Power Electronics Team

    2013-09-01

    A MOSFET based high voltage pulser is utilized to excite a microdischarge (MD), or microdischarge array (MDA) with pulsed voltages of up to 1 kV, with risetime and FWHM on the order of 10 ns and 30 ns, respectively. Additionally, the pulser is capable of pulsing at rep-rates in excess of 35 MHz. However, for these experiments the rep-rate was set on the order of 1 MHz, so as to limit excess energy deposition into the background gas and optimize the energy efficiency of VUV generation. Using VUV capable spectral diagnostics, the VUV emission of the MDs for various pressures (50-800 + Torr) and gases, focused on argon, argon-hydrogen mixtures, and neon-hydrogen mixtures (all of which provide strong emission at λ VUV emission is characterized and compared to results from transient fluid modeling of the MDA. For instance, the MDA turn-on time is recorded to be about 15 ns, which matches the full plasma development time in the model, and the MDA self- capacitance largely determines the turn-off behavior. This research was supported by an AFOSR grant on the Physics of Distributed Plasma Discharges and fellowships from the National Physical Sciences Consortium, supported by Sandia National Laboratories.

  15. Self-Powered Real-Time Arterial Pulse Monitoring Using Ultrathin Epidermal Piezoelectric Sensors.

    Science.gov (United States)

    Park, Dae Yong; Joe, Daniel J; Kim, Dong Hyun; Park, Hyewon; Han, Jae Hyun; Jeong, Chang Kyu; Park, Hyelim; Park, Jung Gyu; Joung, Boyoung; Lee, Keon Jae

    2017-10-01

    Continuous monitoring of an arterial pulse using a pressure sensor attached on the epidermis is an important technology for detecting the early onset of cardiovascular disease and assessing personal health status. Conventional pulse sensors have the capability of detecting human biosignals, but have significant drawbacks of power consumption issues that limit sustainable operation of wearable medical devices. Here, a self-powered piezoelectric pulse sensor is demonstrated to enable in vivo measurement of radial/carotid pulse signals in near-surface arteries. The inorganic piezoelectric sensor on an ultrathin plastic achieves conformal contact with the complex texture of the rugged skin, which allows to respond to the tiny pulse changes arising on the surface of epidermis. Experimental studies provide characteristics of the sensor with a sensitivity (≈0.018 kPa(-1) ), response time (≈60 ms), and good mechanical stability. Wireless transmission of detected arterial pressure signals to a smart phone demonstrates the possibility of self-powered and real-time pulse monitoring system. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Monitoring of concrete structures using the ultrasonic pulse velocity method

    Science.gov (United States)

    Karaiskos, G.; Deraemaeker, A.; Aggelis, D. G.; Van Hemelrijck, D.

    2015-11-01

    Concrete is the material most produced by humanity. Its popularity is mainly based on its low production cost and great structural design flexibility. Its operational and ambient loadings including environmental effects have a great impact in the performance and overall cost of concrete structures. Thus, the quality control, the structural assessment, the maintenance and the reliable prolongation of the operational service life of the existing concrete structures have become a major issue. In the recent years, non-destructive testing (NDT) is becoming increasingly essential for reliable and affordable quality control and integrity assessment not only during the construction of new concrete structures, but also for the existing ones. Choosing the right inspection technique is always followed by a compromise between its performance and cost. In the present paper, the ultrasonic pulse velocity (UPV) method, which is the most well known and widely accepted ultrasonic concrete NDT method, is thoroughly reviewed and compared with other well-established NDT approaches. Their principles, inherent limitations and reliability are reviewed. In addition, while the majority of the current UPV techniques are based on the use of piezoelectric transducers held on the surface of the concrete, special attention is paid to a very promising technique using low-cost and aggregate-size piezoelectric transducers embedded in the material. That technique has been evaluated based on a series of parameters, such as the ease of use, cost, reliability and performance.

  17. Pulse

    Science.gov (United States)

    ... resting for at least 10 minutes. Take the exercise heart rate while you are exercising. ... pulse rate can help determine if the person's heart is pumping. Pulse ... rate gives information about your fitness level and health.

  18. Measurement of negative ion density in a pulsed multicusp negative ion source

    Energy Technology Data Exchange (ETDEWEB)

    Coonan, B.; Mellon, K.N.; Hopkins, M.B. (Dublin City University, Dublin (Ireland))

    1992-10-05

    The production of negative ion beams for use in neutral beam injection heating has become an important area of research in recent years. This paper discusses the negative ion densities measured in a pulsed multicusp volume ion source using photodetachment diagnostic technique. A pulse modulated negative ion source is being used as an alternative to the tandem source and an increase in negative ion extracted current has previously been observed by Hopkins and Mellon. Work with photodetachment quoted in this paper shows an increase in negative ion density during the post discharge similar to previous results obtained using an accelerator to extract the negative ions.

  19. Plasma electron source for the generation of wide-aperture pulsed beam at forevacuum pressures

    Energy Technology Data Exchange (ETDEWEB)

    Oks, E.; Burdovitsin, V.; Medovnik, A.; Yushkov, Yu. [Tomsk State University of Control Systems and Radioelectronics, Tomsk 634050 (Russian Federation)

    2013-02-15

    This article reports on design and application of wide-aperture pulsed beam source, based on hollow cathode discharge. The source is intended for electron beam generation in pressure range 2-15 Pa. Multi-aperture extraction system, used in a source, provided beam cross-section uniformity of 10% on diameter 40 mm. The limiting values of the current density, pulse duration, and accelerating voltage are 350 mA/cm{sup 2}, 250 {mu}s, and 10 kV, respectively. These parameters are sufficient for surface modification of various materials, including non-conducting matters.

  20. Short Pulse High Brightness X-ray Production with the PLEIADES Thomson Scattering Source

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, S G; Barty, C P J; Betts, S M; Brown, W J; Crane, J K; Cross, R R; Fittinghoff, D N; Gibson, D J; Hartemann, F V; Kuba, J; LaSage, G P; Rosenzweig, J B; Slaughter, D R; Springer, P T; Tremaine, A M

    2003-07-01

    We describe PLEIADES, a compact, tunable, high-brightness, ultra-short pulse, Thomson x-ray source. The peak brightness of the source is expected to exceed 10{sup 20} photons/s/0.1% bandwidth/mm{sup 2}/mrad{sup 2}. Initial results are reported and compared to theoretical calculations.

  1. Optimization of Kicker Pulse Bump by Using a SR Monitor at the Photon Factory

    CERN Document Server

    Mitsuhashi, Toshiyuki

    2005-01-01

    We plan to operate the Photon Factory storage ring by top-up injection mode from 2006. To realize this operation mode, remaining coherent oscillation of the stored beam due to error in the injection pulse bump is one of most serious problem. To reducing the error in the injection pulse bump, we calibrated kicking angles of the injection kicker magnets by means of the term by term instantaneous observation of beam profile. We have a SR monitor inside of injection pulse bump. By measureing the tern by tern beam position after the excitation of kicker magnet, we can calibrate the kick angle of the kicker magnet. By using this calibration, we optimized injection pulse bump. As a result, we reduced amplitude of remaining coherent oscillation less than 1/4 of the 1??of the beam size.

  2. In-situ monitoring during pulsed laser deposition using RHEED at high pressure

    NARCIS (Netherlands)

    Blank, David H.A.; Rijnders, Augustinus J.H.M.; Koster, Gertjan; Rogalla, Horst

    1998-01-01

    Reflection high energy electron diffraction (RHEED) is, due to its surface sensitivity, often used for the analysis and monitoring of thin film growth in ultra-high vacuum deposition systems. RHEED is usually applied in combination with pulsed laser deposition (PLD) by adjusting the background

  3. Identification of pulse echo impulse responses for multi source transmission

    DEFF Research Database (Denmark)

    Gran, Fredrik; Jensen, Jørgen Arendt

    2004-01-01

    transmitter and receiver pair, using a least squares estimator. The decoding is done instantaneously, making information from several transmitters available after only one transmission. This limits the influence of motion artifacts both in the decoding step and when the STA focusing scheme is applied...... is a mixture of the information corresponding to several transmitters. There is, thus, no direct way of determining which information corresponds to which transmitter, preventing proper focusing. In this paper we decode the received signal by estimating the pulse echo impulse responses between every....... The method is evaluated using the simulation tool Field II. Three point spread functions are simulated where axial movement of 1 m/s is present. The axial resolution for the moving scatterer is 0.249 mm (-3dB) and 0.291 mm (-6dB), which is compared to a standard STA transmission scheme with sequential...

  4. A correlation between pulse diagnosis of human body and health monitoring of structures

    Institute of Scientific and Technical Information of China (English)

    C.C.Chang; Henry T. Y. Yang

    2004-01-01

    The concept of health monitoring is a key aspect of the field of medicine that has been practiced for a long time. A commonly used diagnostic and health monitoring practice is pulse diagnosis, which can be traced back approximately five thousand years in the recorded history of China. With advances in the development of modem technology, the concept of health monitoring of a variety of engineering structures in several applications has begun to attract widespread attention.Of particular interest in this study is the health monitoring of civil structures. It seems natural, and even beneficial, that these two health-monitoring methods, one as applies to the human body and the other to civil structures, should be analyzed and compared. In this paper, the basic concepts and theories of the two monitoring methods are first discussed. Similarities are then summarized and commented upon. It is hoped that this correlation analysis may help provide structural engineers with some insights into the intrinsic concept of using pulse diagnosis in human health monitoring, which may be of some benefit in the development of modern structural health monitoring methods.

  5. The use of lasers and intense pulsed light sources for the treatment of pigmentary lesions.

    Science.gov (United States)

    Chan, H H L; Kono, T

    2004-10-01

    Lasers and intense pulsed light sources are frequently used for the treatment of pigmented lesions, and the appropriate selection of devices for different lesions is vital to achieving satisfactory clinical outcomes. In dark-skinned patients, the risk of post-inflammatory hyperpigmentation is of particular importance. In general, long-pulse laser and intense pulsed light sources can be effective with a low risk of post-inflammatory hyperpigmentation (PIH) when used for the treatment of lentigines. However, for dermal pigmentation and tattoo, Q-switched lasers are effective, with a lower risk of complications. In the removal of melanocytic nevi, a combined approach with a long-pulse pigmented laser and a Q-switched laser is particularly applicable.

  6. Intelligent pulse light source in the performance calibration system of two-dimensional neutron detector

    Science.gov (United States)

    Yang, Lei; Zhao, Xiao-Fang

    2017-07-01

    Chinese Spallation Neutron Source (CSNS) project will use numerous two-dimensional (2D) neutron detectors whose ZnS (Ag) scintillator is doped with 6Li. To ensure the consistency of all neutron detectors, a calibration system for the performance of 2D neutron detectors is designed. For radiation protection, the state control of the radiation source gets more and more strict. It is impossible to directly carry out experiments with massive radioactive particles. Thus, the following scheme has been designed. The controlled pulsed laser light source on a 2D mobile platform is used to replace the neutron bombardment to generate the photon. The pulse signal drives the laser diode to generate pulse light. The pulse light source located on the 2D platform is controlled by the core controller, and goes to the wavelength shift fiber through the optical fiber. The host computer (PC) receives the signal from the electronics system, processes data, and automatically calibrates the performance parameters. As shown by the experimental results, the pulse light source can perfectly meet all requirements of 2D neutron detector calibration system.

  7. 3D target array for pulsed multi-sourced radiography

    Science.gov (United States)

    Le Galloudec, Nathalie Joelle

    2016-02-23

    The various technologies presented herein relate to the generation of x-rays and other charged particles. A plurality of disparate source materials can be combined on an array to facilitate fabrication of co-located mixed tips (point sources) which can be utilized to form a polychromatic cloud, e.g., a plurality of x-rays having a range of energies and or wavelengths, etc. The tips can be formed such that the x-rays are emitted in a direction different to other charged particles to facilitate clean x-ray sourcing. Particles, such as protons, can be directionally emitted to facilitate generation of neutrons at a secondary target. The various particles can be generated by interaction of a laser irradiating the array of tips. The tips can be incorporated into a plurality of 3D conical targets, the conical target sidewall(s) can be utilized to microfocus a portion of a laser beam onto the tip material.

  8. Shaping the electron beams with submicrosecond pulse duration in sources and electron accelerators with plasma emitters

    CERN Document Server

    Gushenets, V I

    2001-01-01

    One studies the techniques in use to shape submicrosecond electron beams and the physical processes associated with extraction of electrons from plasma in plasma emitters. Plasma emitter base sources and accelerators enable to generate pulse beams with currents varying from tens of amperes up to 10 sup 3 A, with current densities up to several amperes per a square centimeter, with pulse duration constituting hundreds of nanoseconds and with high frequencies of repetition

  9. A compact picosecond pulsed laser source using a fully integrated CMOS driver circuit

    Science.gov (United States)

    He, Yuting; Li, Yuhua; Yadid-Pecht, Orly

    2016-03-01

    Picosecond pulsed laser source have applications in areas such as optical communications, biomedical imaging and supercontinuum generation. Direct modulation of a laser diode with ultrashort current pulses offers a compact and efficient approach to generate picosecond laser pulses. A fully integrated complementary metaloxide- semiconductor (CMOS) driver circuit is designed and applied to operate a 4 GHz distributed feedback laser (DFB). The CMOS driver circuit combines sub-circuits including a voltage-controlled ring oscillator, a voltagecontrolled delay line, an exclusive-or (XOR) circuit and a current source circuit. Ultrashort current pulses are generated by the XOR circuit when the delayed square wave is XOR'ed with the original square wave from the on-chip oscillator. Circuit post-layout simulation shows that output current pulses injected into an equivalent circuit load of the laser have a pulse full width at half maximum (FWHM) of 200 ps, a peak current of 80 mA and a repetition rate of 5.8 MHz. This driver circuit is designed in a 0.13 μm CMOS process and taped out on a 0.3 mm2 chip area. This CMOS chip is packaged and interconnected with the laser diode on a printed circuit board (PCB). The optical output waveform from the laser source is captured by a 5 GHz bandwidth photodiode and an 8 GHz bandwidth oscilloscope. Measured results show that the proposed laser source can output light pulses with a pulse FWHM of 151 ps, a peak power of 6.4 mW (55 mA laser peak forward current) and a repetition rate of 5.3 MHz.

  10. Matching a (sub)nanosecond pulse source to a corona plasma reactor

    Science.gov (United States)

    Huiskamp, T.; Beckers, F. J. C. M.; Hoeben, W. F. L. M.; van Heesch, E. J. M.; Pemen, A. J. M.

    2016-10-01

    In this paper we investigate the energy transfer from the pulses of a (sub)nanosecond pulse source to the plasma in a corona-plasma reactor. This energy transfer (or ‘matching’) should be as high as possible. We studied the effect of multiple parameters on matching, such as the reactor configuration, the pulse duration and amplitude and the energy density. The pulse reflection on the reactor interface has a significant influence on matching, and should be as low as possible to transfer the most energy into the reactor. We developed a multiple-wire inner conductor for the reactor which decreases the vacuum impedance of the reactor to decrease the pulse reflection on the reactor interface while maintaining a high electric field on the wire. The results were very encouraging and showed an energy transfer efficiency of over 90 percent. The matching results further show that there is only a small effect on the matching between different wire diameters. In addition, a long reactor and a long pulse result in the best matching due to the more intense plasma that is generated in these conditions. Finally, even without the multiple-wire reactor, we are able to achieve a very good matching (over 80 percent) between our pulse source and the reactor.

  11. Negative hydrogen ion production in multicusp volume source with a pulsed discharge (abstract)a)

    Science.gov (United States)

    Bacal, M.; Belchenko, Yu. I.

    1996-03-01

    The pulsed operation of a negative ion volume source has been investigated, both with a magnetic filter present and without it, under conditions of full-scale acceleration of the extracted negative hydrogen ion beam. We report the observation of three afterglow negative ion peaks. As the negative ion current during the discharge pulse, each of the afterglow peaks can be optimized by varying the pressure, the plasma electrode bias and the extraction voltage. Under optimum conditions, the negative ion current during the discharge pulse exceeds the afterglow peaks.

  12. Tip-based source of femtosecond electron pulses at 30 keV

    Energy Technology Data Exchange (ETDEWEB)

    Hoffrogge, Johannes; Paul Stein, Jan [Max Planck Institute of Quantum Optics, Hans-Kopfermann-Str. 1, 85748 Garching (Germany); Krüger, Michael; Förster, Michael; Hammer, Jakob; Ehberger, Dominik; Hommelhoff, Peter, E-mail: peter.hommelhoff@fau.de [Max Planck Institute of Quantum Optics, Hans-Kopfermann-Str. 1, 85748 Garching (Germany); Department für Physik, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstr. 1, 91058 Erlangen (Germany); Baum, Peter [Max Planck Institute of Quantum Optics, Hans-Kopfermann-Str. 1, 85748 Garching (Germany); Ludwig-Maximilians-Universität München, Am Coulombwall 1, 85748 Garching (Germany)

    2014-03-07

    We present a nano-scale photoelectron source, optimized for ultrashort pulse durations and well-suited for time-resolved diffraction and advanced laser acceleration experiments. A tungsten tip of several-ten-nanometers diameter mounted in a suppressor-extractor electrode configuration allows the generation of 30 keV electron pulses with an estimated pulse duration of 9 fs (standard deviation; 21 fs full width at half maximum) at the gun exit. We infer the pulse duration from particle tracking simulations, which are in excellent agreement with experimental measurements of the electron-optical properties of the source in the spatial domain. We also demonstrate femtosecond-laser triggered operation of the apparatus. The temporal broadening of the pulse upon propagation to a diffraction sample can be greatly reduced by collimating the beam. Besides the short electron pulse duration, a tip-based source is expected to feature a large transverse coherence and a nanometric emittance.

  13. A Repetitive Nanosecond Pulse Source for Generation of Large Volume Streamer Discharge

    Institute of Scientific and Technical Information of China (English)

    TAO Fengbo; ZHANG Qiaogen; GAO Bo; WANG Hu; LI Zhou

    2008-01-01

    Using a unipolar pulse with the rise time and the pulse duration in the order of microsecond as the primary pulse,a nanosecond pulse with the repetitive frequency of several kilohertz is generated by a spark gap switch.By varying both the inter-pulse duration and the pulse frequency,the voltage recovery rate of the spark gap switch is investigated at different working conditions such as the gas pressure,the gas composition as well as the bias voltage.The results reveal that either increase in gas pressure or addition of SF6 to the air can increase the voltage recovery rate.The effect of gas composition on the voltage recovery rate is discussed based on the transferring and distribution of the residual space charges.The repetitive nanosecond pulse source is also applied to the generation of large volume,and the discharge currents are measured to investigate the effect of pulse repetition rate on the large volume streamer discharge.

  14. Testing a scale pulsed modulator for an IEC neutron source into a resistive load

    Energy Technology Data Exchange (ETDEWEB)

    Dale, Gregory E [Los Alamos National Laboratory; Wheat, Robert M [Los Alamos National Laboratory; Aragonez, Robert [Los Alamos National Laboratory

    2009-01-01

    A 1/10th scaled prototype pulse modulator for an Inertial Electrostatic Confinement (IEC) neutron source has been designed and tested at Los Alamos National Laboratory (LANL). The scaled prototype modulator is based on a solid-state Marx architecture and has an output voltage of 13 kV and an output current of 10 A. The modulator has a variable pulse width between 50 {micro}s and 1 ms with < 5% droop at all pulse widths. The modulator operates with a duty factor up to 5% and has a maximum pulse repetition frequency of 1 kHz. The use of a solid-state Marx modulator in this application has several potential benefits. These benefits include variable pulse width and amplitude, inherent switch overcurrent and transient overvoltage protection, and increased efficiency over DC supplies used in this application. Several new features were incorporated into this design including inductorless charging, fully snubberless operation, and stage fusing. The scaled prototype modulator has been tested using a 1 k{Omega} resistive load. Test results are given. Short (50 {micro}s) and long (1 ms) pulses are demonstrated as well as high duty factor operation (1 kHz rep rate at a 50 {micro}s pulse width for a 5% duty factor). Pulse agility of the modulator is demonstrated through turning the individual Marx stages on and off in sequence producing ramp, pyramid, and reverse pyramid waveforms.

  15. Development and characterization of a high yield transportable pulsed neutron source with efficient and compact pulsed power system

    Science.gov (United States)

    Verma, Rishi; Mishra, Ekansh; Dhang, Prosenjit; Sagar, Karuna; Meena, Manraj; Shyam, Anurag

    2016-09-01

    The results of characterization experiments carried out on a newly developed dense plasma focus device based intense pulsed neutron source with efficient and compact pulsed power system are reported. Its high current sealed pseudospark switch based low inductance capacitor bank with maximum stored energy of ˜10 kJ is segregated into four modules of ˜2.5 kJ each and it cumulatively delivers peak current in the range of 400 kA-600 kA (corresponding to charging voltage range of 14 kV-18 kV) in a quarter time period of ˜2 μs. The neutron yield performance of this device has been optimized by discretely varying deuterium filling gas pressure in the range of 6 mbar-11 mbar at ˜17 kV/550 kA discharge. At ˜7 kJ/8.5 mbar operation, the average neutron yield has been measured to be in the order of ˜4 × 109 neutrons/pulse which is the highest ever reported neutron yield from a plasma focus device with the same stored energy. The average forward to radial anisotropy in neutron yield is found to be ˜2. The entire system is contained on a moveable trolley having dimensions 1.5 m × 1 m × 0.7 m and its operation and control (up to the distance of 25 m) are facilitated through optically isolated handheld remote console. The overall compactness of this system provides minimum proximity to small as well as large samples for irradiation. The major intended application objective of this high neutron yield dense plasma focus device development is to explore the feasibility of active neutron interrogation experiments by utilization of intense pulsed neutron sources.

  16. Investigation of the vertical instability at the Argonne Intense Pulsed Neutron Source

    Science.gov (United States)

    Wang, Shaoheng; Dooling, J. C.; Harkay, K. C.; Kustom, R. L.; McMichael, G. E.

    2009-10-01

    The rapid cycling synchrotron of the intense pulsed neutron source at Argonne National Laboratory normally operates at an average beam current of 14 to 15μA, accelerating protons from 50 to 450 MeV 30 times per second. The beam current is limited by a single-bunch vertical instability that occurs in the later part of the 14 ms acceleration cycle. By analyzing turn-by-turn beam position monitor data, two cases of vertical beam centroid oscillations were discovered. The oscillations start from the tail of the bunch, build up, and develop toward the head of the bunch. The development stops near the bunch center and oscillations remain localized in the tail for a relatively long time (2-4 ms, 1-2×104 turns). This vertical instability is identified as the cause of the beam loss. We compared this instability with a head-tail instability that was purposely induced by switching off sextupole magnets. It appears that the observed vertical instability is different from the classical head-tail instability.

  17. The CRRES IDM spacecraft experiment for insulator discharge pulses. [Internal Discharge Monitor

    Science.gov (United States)

    Frederickson, A. R.; Mullen, E. G.; Kerns, K. J.; Robinson, P. A.; Holeman, E. G.

    1993-01-01

    The Internal Discharge Monitor (IDM) is designed to observe electrical pulses from common electrical insulators in space service. The characteristics of the instrument are described. The IDM was flown on the Combined Release and Radiation Effects Satellite (CRRES). The sixteen insulator samples included G10 circuit boards, FR4 and PTFE fiberglass circuit boards, FEP Teflon, alumina, and wires with common insulations. The samples are fully enclosed, mutually isolated, and space radiation penetrates 0.02 cm of aluminum before striking the samples. Published data in the literature provides a simple method for determining the flux of penetrating electrons. The pulse rate is compared to the penetrating flux of electrons.

  18. Concurrent validity of resting pulse-rate measurements: a comparison of 2 smartphone applications, the polar H7 belt monitor, and a pulse oximeter with bluetooth.

    Science.gov (United States)

    Cheatham, Scott W; Kolber, Morey J; Ernst, Michael P

    2015-05-01

    Pulse rate is commonly measured manually or with commercial wrist or belt monitors. More recently, pulse-rate monitoring has become convenient with the use of mobile technology that allows monitoring through a smartphone camera. This optical technology offers many benefits, although the clinimetric properties have not been extensively studied. Observational study of reliability Setting: University kinesiology laboratory. 30 healthy, recreationally active adults. Concurrent measurement of pulse rate using 2 smartphone applications (fingertip, face-scan,) with the Polar H7 belt and pulse oximeter. Average resting pulse rate for 5 min in 3 positions (supine, sitting, and prone). Concurrent validity in supine and standing was good between the 2 applications and the Polar H7 (intraclass correlation coefficient [ICC] .80-.98) and pulse oximeter (ICC .82-.98). For sitting, the validity was good between the fingertip application, Polar H7 (ICC .97), and pulse oximeter (ICC .97). The face-scan application had moderate validity with the Polar H7 (ICC .74) and pulse oximeter (ICC .69). The minimal detectable change (MDC90) between the fingertip application and Polar H7 ranged from 1.38 to 4.36 beats/min (BPM) and from 0.69 to 2.97 BPM for the pulse oximeter with both positions. The MDC90 between the face-scan application and Polar H7 ranged from 11.88 to 12.83 BPM and from 0.59 to 17.72 BPM for the pulse oximeter. The 95% limits of agreement suggest that the fingertip application may vary between 2.40 and 3.59 BPM with the Polar H7 and between 3.40 and 3.42 BPM with the pulse oximeter. The face-scan application may vary between 3.46 and 3.52 BPM with the Polar H7 and between 2.54 and 3.46 BPM with the pulse oximeter. Pulse-rate measurements may be effective using a fingertip application, belt monitor, and pulse oximeter. The fingertip scanner showed superior results compared with the face scanner, which only demonstrated modest validity compared with the Polar H7 and pulse

  19. Generating picosecond x-ray pulses in synchrotron light sources using dipole kickers

    Directory of Open Access Journals (Sweden)

    W. Guo

    2007-02-01

    Full Text Available The duration of the x-ray pulse generated at a synchrotron light source is typically tens of picoseconds. Shorter pulses are highly desired by the users. In electron storage rings, the vertical beam size is usually orders of magnitude less than the bunch length due to radiation damping; therefore, a shorter pulse can be obtained by slitting the vertically tilted bunch. Zholents proposed tilting the bunch using rf deflection. We found that tilted bunches can also be generated by a dipole magnet kick. A vertical tilt is developed after the kick in the presence of nonzero chromaticity. The tilt was successfully observed and a 4.2-ps pulse was obtained from a 27-ps electron bunch at the Advanced Photon Source. Based on this principle, we propose a short-pulse generation scheme that produces picosecond x-ray pulses at a repetition rate of 1–2 kHz, which can be used for pump-probe experiments.

  20. Hundred joules plasma focus device as a potential pulsed source for in vitro cancer cell irradiation

    Science.gov (United States)

    Jain, J.; Moreno, J.; Andaur, R.; Armisen, R.; Morales, D.; Marcelain, K.; Avaria, G.; Bora, B.; Davis, S.; Pavez, C.; Soto, L.

    2017-08-01

    Plasma focus devices may arise as useful source to perform experiments aimed to study the effects of pulsed radiation on human cells in vitro. In the present work, a table top hundred joules plasma focus device, namely "PF-400J", was adapted to irradiate colorectal cancer cell line, DLD-1. For pulsed x-rays, the doses (energy absorbed per unit mass, measured in Gy) were measured using thermoluminescence detectors (TLD-100 dosimeters). The neutron fluence and the average energy were used to estimate the pulsed neutron doses. Fifty pulses of x-rays (0.12 Gy) and fifty pulses of neutrons (3.5 μGy) were used to irradiate the cancer cells. Irradiation-induced DNA damage and cell death were assessed at different time points after irradiation. Cell death was observed using pulsed neutron irradiation, at ultralow doses. Our results indicate that the PF-400J can be used for in vitro assessment of the effect of pulsed radiation in cancer cell research.

  1. Events as power source: wireless sustainable corrosion monitoring.

    Science.gov (United States)

    Sun, Guodong; Qiao, Guofu; Zhao, Lin; Chen, Zhibo

    2013-12-17

    This study presents and implements a corrosion-monitoring wireless sensor platform, EPS (Events as Power Source), which monitors the corrosion events in reinforced concrete (RC) structures, while being powered by the micro-energy released from the corrosion process. In EPS, the proposed corrosion-sensing device serves both as the signal source for identifying corrosion and as the power source for driving the sensor mote, because the corrosion process (event) releases electric energy; this is a novel idea proposed by this study. For accumulating the micro-corrosion energy, we integrate EPS with a COTS (Commercial Off-The-Shelf) energy-harvesting chip that recharges a supercapacitor. In particular, this study designs automatic energy management and adaptive transmitted power control polices to efficiently use the constrained accumulated energy. Finally, a set of preliminary experiments based on concrete pore solution are conducted to evaluate the feasibility and the efficacy of EPS.

  2. Events as Power Source: Wireless Sustainable Corrosion Monitoring

    Directory of Open Access Journals (Sweden)

    Guodong Sun

    2013-12-01

    Full Text Available This study presents and implements a corrosion-monitoring wireless sensor platform, EPS (Events as Power Source, which monitors the corrosion events in reinforced concrete (RC structures, while being powered by the micro-energy released from the corrosion process. In EPS, the proposed corrosion-sensing device serves both as the signal source for identifying corrosion and as the power source for driving the sensor mote, because the corrosion process (event releases electric energy; this is a novel idea proposed by this study. For accumulating the micro-corrosion energy, we integrate EPS with a COTS (Commercial Off-The-Shelf energy-harvesting chip that recharges a supercapacitor. In particular, this study designs automatic energy management and adaptive transmitted power control polices to efficiently use the constrained accumulated energy. Finally, a set of preliminary experiments based on concrete pore solution are conducted to evaluate the feasibility and the efficacy of EPS.

  3. LENS-a pulsed neutron source for education and research

    Energy Technology Data Exchange (ETDEWEB)

    Baxter, David V. [Physics Department, Indiana University, Bloomington, IN 47405 (United States)]. E-mail: baxterd@indiana.edu; Cameron, J.M. [Physics Department, Indiana University, Bloomington, IN 47405 (United States); Leuschner, M.B. [Physics Department, Indiana University, Bloomington, IN 47405 (United States); Meyer, H.O. [Physics Department, Indiana University, Bloomington, IN 47405 (United States); Nann, H. [Physics Department, Indiana University, Bloomington, IN 47405 (United States); Snow, W.M. [Physics Department, Indiana University, Bloomington, IN 47405 (United States)

    2005-04-21

    At the Indiana University Cyclotron Facility construction of a new source of cold neutrons has begun. Neutrons are generated by stopping 13 MeV protons in a beryllium target, located at the center of a moderator structure. Cold neutrons are emitted from a slab of frozen methane. Three beam lines deliver neutrons for scattering experiments, radiography and moderator studies. The purpose of the project is to develop a low-cost, small-scale facility, suitable for a university or an industrial setting, to provide a testing ground of instrumentation destined for use at a larger facility, to improve awareness of the use of neutron probes in a wide range of applications, and to offer a training opportunity for future neutron physicists.

  4. Application of a pulsed, RF-driven, multicusp source for low energy plasma immersion ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    Wengrow, A.B.; Leung, K.N.; Perkins, L.T.; Pickard, D.S.; Rickard, M.; Williams, M.D. [Lawrence Berkeley Lab., CA (United States); Tucker, M. [Spectrum Sciences, Inc., Santa Clara, CA (United States)

    1996-06-01

    The multicusp ion source can produce large volumes of uniform, quiescent, high density plasmas. A plasma chamber suited for plasma immersion ion implantation (PIII) was readily made. Conventional PIII pulses the bias voltage applied to the substrate which is immersed in a CW mode plasma. Here, a method by which the plasma itself is pulsed was developed. Typically pulse lengths of 500 {mu}s are used and are much shorter than that of the substrate voltage pulse (5-15 ms). This approach, together with low gas pressures and low bias voltages, permits the constant energy implantation of an entire wafer simultaneously without glow discharge. Results show that this process can yield implant currents of up to 2.5 mA/cm{sup 2}; thus very short implant times can be achieved. Uniformity of the ion flux is also discussed. As this method can be scaled to any dimension, it can be made to handle any size wafer.

  5. H- extraction from electron-cyclotron-resonance-driven multicusp volume source operated in pulsed mode

    Science.gov (United States)

    Svarnas, P.; Bacal, M.; Auvray, P.; Béchu, S.; Pelletier, J.

    2006-03-01

    H2 microwave (2.45GHz) pulsed plasma is produced from seven elementary electron cyclotron resonance sources installed into the magnetic multipole chamber "Camembert III" (École Polytechnique—Palaiseau) from which H- extraction takes place. The negative-ion and electron extracted currents are studied through electrical measurements and the plasma parameters by means of electrostatic probe under various experimental conditions. The role of the plasma electrode bias and the discharge duty cycle in the extraction process is emphasized. The gas breakdown at the beginning of every pulse gives rise to variations of the plasma characteristic parameters in comparison with those established at the later time of the pulse, where the electron temperature, the plasma potential, and the floating potential converge to the values obtained for a continuous plasma. The electron density is significantly enhanced in the pulsed mode.

  6. Picosecond pulse generation in a hybrid Q-switched laser source by using a microelectromechanical mirror.

    Science.gov (United States)

    Couderc, Vincent; Crunteanu, Aurelian; Fabert, Marc; Doutre, Florent; El Bassri, Farid; Pagnoux, Dominique; Jalocha, Alain

    2012-02-27

    We present a novel Q-switched laser source using a micro-optical-electromechanical mirror (MOEM) designed for short pulse emission. It is based on a hybrid configuration including a passively Q-switched microchip laser coupled to a fiber cavity closed by a cantilever type MOEM acting as an active modulator. This specially designed mirror with a single reflecting gold membrane is switched by low bias voltage ~50 V (peak to peak). This device emits pulses at tunable repetition rates up to 1.6 kHz, with ~564 ps duration and 3.4 kW peak power, which constitutes the shortest pulse duration ever reported with MOEMs based pulsed lasers.

  7. Pulsed sextupole injection for Beijing Advanced Photon Source with ultralow emittance

    CERN Document Server

    Yi, JIAO

    2013-01-01

    In this paper we present the physical design of the pulsed sextupole injection system for Beijing Advanced Photon Source (BAPS) with an ultralow emittance. The BAPS ring lattice is designed in such a way that two options of pulsed sextupole injection are allowed, i.e., with septum and pulsed sextupole in different drift spaces or in the same drift space. We give the magnetic parameters of the injection system and the optimal condition of the optical functions for both options. In addition, we find that the pulsed sextupole induces position-dependent dispersive effect and causes non-ignorable effect on the injection efficiency in a storage ring with a relatively small acceptance, which should be well considered.

  8. Neutronic studies on decoupled hydrogen moderator for a short-pulse spallation source

    Energy Technology Data Exchange (ETDEWEB)

    Harada, Masahide [Neutron Facility Group, Center for Proton Accelerator Facility, Japan Atomic Energy Research Institute, Tokai-mura, Naka-gun, Ibaraki-ken 319-1195 (Japan)]. E-mail: harada@cens.tokai.jaeri.go.jp; Watanabe, Noboru [Neutron Facility Group, Center for Proton Accelerator Facility, Japan Atomic Energy Research Institute, Tokai-mura, Naka-gun, Ibaraki-ken 319-1195 (Japan); Teshigawara, Makoto [Neutron Facility Group, Center for Proton Accelerator Facility, Japan Atomic Energy Research Institute, Tokai-mura, Naka-gun, Ibaraki-ken 319-1195 (Japan); Kai, Tetsuya [Neutron Facility Group, Center for Proton Accelerator Facility, Japan Atomic Energy Research Institute, Tokai-mura, Naka-gun, Ibaraki-ken 319-1195 (Japan); Ikeda, Yujiro [Neutron Facility Group, Center for Proton Accelerator Facility, Japan Atomic Energy Research Institute, Tokai-mura, Naka-gun, Ibaraki-ken 319-1195 (Japan)

    2005-02-21

    Neutronic studies of decoupled hydrogen moderators were performed by calculations taking into account para hydrogen content, decoupling energy, moderator dimensions/shapes and reflector material. Low-energy parts of calculated spectral intensities with different para hydrogen contents were analyzed by a modified Maxwell function to characterize neutron spectra. The result shows that a 100% para hydrogen moderator gives the highest pulse peak intensity together with the narrowest pulse width and the shortest decay times. Pulse broadening with a reflector was explained by time distributions of source neutrons entering into the moderator through a decoupler. Material dependence of time distribution was studied. A decoupling energy higher than 1 eV does not bring about a large improvement in pulse widths and decay times, even at a large penalty in the peak intensity. The optimal moderator thickness was also discussed for a rectangular parallelepipe-shaped and a canteen-shaped moderator.

  9. Generation of Short X-Ray Pulses Using Crab Cavities at the Advanced Photon Source

    CERN Document Server

    Harkay, Katherine C; Chae, Yong-Chul; Decker, Glenn; Dejus, Roger J; Emery, Louis; Guo, Weiming; Horan, Douglas; Kim, Kwang-Je; Kustom, Robert; Mills, Dennis M; Milton, Stephen; Pile, Geoffery; Sajaev, Vadim; Shastri, Sarvjit D; Waldschmidt, Geoff J; White, Marion; Yang Bing Xin; Zholents, Alexander

    2005-01-01

    There is growing interest within the user community to utilize the pulsed nature of synchrotron radiation from storage ring sources. Conventional third-generation light sources can provide pulses on the order of 100 ps but typically cannot provide pulses of about 1 ps that some users now require to advance their research programs. However, it was recently proposed by A. Zholents et al. to use rf orbit deflection to generate subpicosecond X-ray pulses.* In this scheme, two crab cavities are used to deliver a longitudinally dependent vertical kick to the beam, thus exciting longitudinally correlated vertical motion of the electrons. This makes it possible to spatially separate the radiation coming from different longitudinal parts of the beam. An optical slit can then be used to slice out a short part of the radiation pulse, or an asymetrically cut crystal can be used to compress the radiation in time. In this paper, we present a feasibility study of this method applied to the Advanced Photon Source. We find th...

  10. Light inactivation of food-related pathogenic bacteria using a pulsed power source.

    Science.gov (United States)

    MacGregor, S J; Rowan, N J; Mcllvaney, L; Anderson, J G; Fouracre, R A; Farish, O

    1998-08-01

    The effects of high intensity light emissions, produced by a novel pulsed power energization technique (PPET), on the survival of bacterial populations of verocytotoxigenic Escherichia coli (serotype 0157:H7) and Listeria monocytogenes (serotype 4b) were investigated. Using this PPET approach, many megawatts (MW) of peak electrical power were dissipated in the light source in an extremely short energization time (about 1 microsecond). The light source was subjected to electric field levels greater than could be achieved under conventional continuous operation, which led to a greater production of the shorter bacteriocidal wavelengths of light. In the exposure experiments, pre-determined bacterial populations were spread onto the surface of Trypone Soya Yeast Extract Agar and were then treated to a series of light pulses (spectral range of 200-530 nm) with an exposure time ranging from 1 to 512 microseconds. While results showed that as few as 64 light pulses of 1 microsecond duration were required to reduce E. coli 0157:H7 populations by 99.9% and Listeria populations by 99%, the greater the number of light pulses the larger the reduction in cell numbers (P pulsed light emissions can significantly reduce populations of E. coli 0157:H7 and L. monocytogenes on exposed surfaces with exposure times which are 4-6 orders of magnitude lower than those required using continuous u.v. light sources.

  11. Low-noise pulsed current source for magnetic-field measurements of magnets for accelerators

    Science.gov (United States)

    Omelyanenko, M. M.; Borisov, V. V.; Donyagin, A. M.; Khodzhibagiyan, H. G.; Kostromin, S. A.; Makarov, A. A.; Shemchuk, A. V.

    2017-01-01

    The schematic diagram, design, and technical characteristics of the pulsed current source developed and produced for the magnetic-field measurement system of superconducting magnets for accelerators are described. The current source is based on the current regulator with pass transistor bank in the linear mode. Output current pulses (0-100 A) are produced by utilizing the energy of the preliminarily charged capacitor bank (5-40 V), which is additionally charged between pulses. The output current does not have the mains frequency and harmonics ripple. The relative noise level is less than-100 dB (or 10-5) of RMS value (it is defined as the ratio of output RMS noise current to a maximal output current of 100 A within the operating bandwidth, expressed in dB). The work was performed at the Veksler and Baldin Laboratory of High Energy Physics, Joint Institute for Nuclear Research (JINR).

  12. Some general reflections on {open_quotes}long pulse{close_quotes} neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, G.S. [Paul Scherrer Inst., Villigen (Switzerland)

    1995-12-31

    A long pulse spallation neutron source (LPSS) having about 20 times more time average thermal flux than its short pulse counterpart (SPSS) at the same proton beam power and featuring a pronounced time structure not available on CW sources (CWNS) of equal time average flux can in principle host instruments typical for both classes of facilities. While the need for additional choppers introduces some restrictions on inverted time of flight techniques typical for SPSS and high incident neutron energies are not easier to use on LPSS than on CWNS, taking advantage of the pulsed nature of the neutron flux can enhance significantly the performance of direct time of flight instruments and of crystal spectrometers or diffractometers. In the paper some of the options are reviewed in a general manner and criteria are discussed which can be used to optimize the performance enhancement.

  13. A twin-type airflow pulse ionization chamber for continuous alpha-radioactivity monitoring in atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Kada, Wataru, E-mail: kada@nf.eie.eng.osaka-u.ac.j [Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan); Dwaikat, Nidal; Datemichi, Jun; Sato, Fuminobu; Murata, Isao; Kato, Yushi; Iida, Toshiyuki [Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan)

    2010-10-15

    A simple and inexpensive twin-type airflow pulse ionization chamber was developed for the continuous monitoring of alpha-radioactivity in atmosphere under high humidity condition. The symmetrical structure of the twin-type ionization chamber was effective in the improvement of the ratio of signal to noise in the measurement of pulses induced by alpha-rays. Outdoor alpha-ray measurement was well performed with this ionization chamber by applying sufficiently high bias voltage to the electrodes, except for at very high humidity conditions. It was confirmed that the declination of the counting efficiency due to wetting was easily recovered by the dry-up of the inside of the chamber. Alpha-radioactivity from radon and other alpha-emitting radionuclide in atmosphere was satisfactorily monitored by the detector.

  14. High-resolution VUV spectrometer/detector investigations of rare-earth pulsed plasma source (abstract)

    Science.gov (United States)

    Roberts, J. R.; Cromer, C. L.; Bridges, J. M.; Lucatorto, T. B.

    1985-05-01

    A 1.5-m grazing incidence spectrometer with a channel electron multiplier (CEMA) and electronic readout detector has been incorporated with a rare-earth target, pulsed plasma, continuum source. The spectrometer is compact and portable while maintaining high resolution. The CEMA detector consists of a single multichannel plate (MCP) with coned-shaped input pores which are cut at a 15-degree bias to improve efficiency at grazing angles. The source is a rare-earth plasma generated by a 10-J ruby laser producing intense continuum emission for wavelengths from 170 to 5 nm. This system will be used for both stationary and transient high-resolution atomic photoabsorption spectroscopy. The pulsed plasma source itself will be investigated for suitability as a radiometric transfer standard source. Preliminary results obtained with this integrated system will be discussed.

  15. Inelastic scattering research at a 1 MW long pulse spallation neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Carlile, C.J.

    1995-12-31

    The brief was, with respect to the LPSS bench mark design supplied (60 Hz, 1 MW, Imsec proton pulse, with a split, non-fissile target and 4 moderators in a flux trap geometry design), to identify a set of instruments, and to assess their performance with respect to existing spectrometers on other sources. Any modifications to the existing instruments which would make them more effective on the bench-mark source, or conversely, any modifications to the source bench-mark required by the proposed instruments were to be identified, as were any uncertainties in the estimated performances, or any R & D needed to make the proposed instruments viable. Any new instrument concepts specifically matched to the long pulse itself were to be identified and assessed. This process was to result in an indicative list of instruments for the source. A figure of around 10 spectrometers was to be aimed for.

  16. The late Paleozoic oxygen pulse and accumulations of petroleum source rocks and coal

    Directory of Open Access Journals (Sweden)

    PAVLE I. PREMOVIC

    2006-02-01

    Full Text Available Recent geophysical and geochemical data and theoretical modeling indicate high levels of atmospheric O2 (up to 35% during the Carboniferous-Permian. I suggest that this O2 pulse had a substantial impact on global accumulations of petroleum source rocks and coal during this geological period.

  17. Pile-up corrections in laser-driven pulsed x-ray sources

    CERN Document Server

    Hernández, Guillermo

    2016-01-01

    A formalism for treating the pile-up produced in laser-driven pulsed x-ray sources has been developed. It allows the direct use of x-ray spectroscopy without artificially decreasing the number of counts in the detector. The influence of the pile-up on the overestimation of temperature parameters is shown up.

  18. Faint laser pulses versus a single-photon source in free space quantum cryptography

    Science.gov (United States)

    Molotkov, S. N.; Potapova, T. A.

    2016-03-01

    In this letter we present estimates for the distance of secret key transmission through free space for three different protocols of quantum key distribution: for BB84 and phase time-coding protocols in the case of a strictly single-photon source, and for the relativistic quantum key distribution protocol in the case of faint laser pulses.

  19. Pulsed energy-time entangled twin-photon source for quantum communication

    CERN Document Server

    Brendel, J; Tittel, W; Zbinden, H

    1999-01-01

    A pulsed source of energy-time entangled photon pairs pumped by a standard laser diode is proposed and demonstrated. The basic states can be distinguished by their time of arrival. This greatly simplifies the realization of 2-photon quantum cryptography, Bell state analyzers, quantum teleportation, dense coding, entanglement swapping, GHZ-states sources, etc. Moreover the entanglement is well protected during photon propagation in telecom optical fibers, opening the door to few-photon applications of quantum communication over long distances.

  20. A versatile, pulsed anion source utilizing plasma-entrainment: Characterization and applications

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Yu-Ju; Lehman, Julia H.; Lineberger, W. Carl, E-mail: wcl@jila.colorado.edu [JILA and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309 (United States)

    2015-01-28

    A novel pulsed anion source has been developed, using plasma entrainment into a supersonic expansion. A pulsed discharge source perpendicular to the main gas expansion greatly reduces unwanted “heating” of the main expansion, a major setback in many pulsed anion sources in use today. The design principles and construction information are described and several examples demonstrate the range of applicability of this anion source. Large OH{sup −}(Ar){sub n} clusters can be generated, with over 40 Ar solvating OH{sup −}. The solvation energy of OH{sup −}(Ar){sub n}, where n = 1-3, 7, 12, and 18, is derived from photoelectron spectroscopy and shows that by n = 12-18, each Ar is bound by about 10 meV. In addition, cis– and trans– HOCO{sup −} are generated through rational anion synthesis (OH{sup −} + CO + M → HOCO{sup −} + M) and the photoelectron spectra compared with previous results. These results, along with several further proof-of-principle experiments on solvation and transient anion synthesis, demonstrate the ability of this source to efficiently produce cold anions. With modifications to two standard General Valve assemblies and very little maintenance, this anion source provides a versatile and straightforward addition to a wide array of experiments.

  1. A versatile, pulsed anion source utilizing plasma-entrainment: Characterization and applications

    Science.gov (United States)

    Lu, Yu-Ju; Lehman, Julia H.; Lineberger, W. Carl

    2015-01-01

    A novel pulsed anion source has been developed, using plasma entrainment into a supersonic expansion. A pulsed discharge source perpendicular to the main gas expansion greatly reduces unwanted "heating" of the main expansion, a major setback in many pulsed anion sources in use today. The design principles and construction information are described and several examples demonstrate the range of applicability of this anion source. Large OH-(Ar)n clusters can be generated, with over 40 Ar solvating OH-. The solvation energy of OH-(Ar)n, where n = 1-3, 7, 12, and 18, is derived from photoelectron spectroscopy and shows that by n = 12-18, each Ar is bound by about 10 meV. In addition, cis- and trans- HOCO- are generated through rational anion synthesis (OH- + CO + M → HOCO- + M) and the photoelectron spectra compared with previous results. These results, along with several further proof-of-principle experiments on solvation and transient anion synthesis, demonstrate the ability of this source to efficiently produce cold anions. With modifications to two standard General Valve assemblies and very little maintenance, this anion source provides a versatile and straightforward addition to a wide array of experiments.

  2. Towards 'smart lasers': self-optimisation of an ultrafast pulse source using a genetic algorithm

    CERN Document Server

    Woodward, R I

    2016-01-01

    Short-pulse fibre lasers are a complex dynamical system possessing a broad space of operating states that can be accessed through control of cavity parameters. Determination of target regimes is a multi-parameter global optimisation problem. Here, we report the implementation of a genetic algorithm to intelligently locate optimum parameters for stable single-pulse mode-locking in a Figure-8 fibre laser, and fully automate the system turn-on procedure. Stable ultrashort pulses are repeatably achieved by employing a compound fitness function that monitors both temporal and spectral output properties of the laser. Our method of encoding photonics expertise into an algorithm and applying machine-learning principles paves the way to self-optimising `smart' optical technologies.

  3. Temporal Evolution of Ion Velocity Distribution Function in a Pulsed Helicon Source

    Science.gov (United States)

    Hardin, Robert; Biloiu, Costel; Compton, Chris; Keesee, Amy; Scime, Earl; Heard, John

    2004-11-01

    We report measurements of the time resolved ion velocity distribution function (ivdf) in a pulsed helicon plasma source using laser induced fluorescence (LIF). Our LIF laser system consists of a 6 W Coherent Innova 300 argon-ion laser that pumps a Coherent 899 tunable ring dye laser tuned to 611.49 nm. The 611.49 nm (air wavelength) photons pump the Ar II 3d^2G_9/2 metastable state to the 4p^2F_7/2 state that decays to the 4s^2D_5/2 state by emitting 460.96 nm photons. The helicon plasma source is pulsed on for 100 ms with a 50% duty cycle. The background emission was subtracted from the fluorescent emission in two different ways: either the laser was mechanically chopped at with a frequency much longer than the rf pulse and lock in amplification employed or multiple acquisitions (typically 50) of pulsed emission with both the laser on and off were obtained. For most plasma conditions, both the parallel and perpendicular ivdf reach equilibrium by 5 ms into the rf pulse. Time dependent measurements of the ivdf will be presented for a range of rf powers, magnetic field strengths, and neutral pressures.

  4. Optical Spectrophotometric Monitoring of Fermi/LAT Bright Sources

    CERN Document Server

    Patiño-Álvarez, V; León-Tavares, J; Valdés, J R; Carramiñana, A; Carrasco, L; Torrealba, J

    2013-01-01

    We describe an ongoing optical spectrophotometric monitoring program of a sample of Fermi/LAT bright sources showing prominent and variable {\\gamma}-ray emission, with the 2.1m telescope at Observatorio Astrof\\'isico Guillermo Haro (OAGH) located in Cananea, Sonora, M\\'exico. Our sample contains 11 flat spectrum radio quasars (FSRQ) and 1 Narrow Line Seyfert 1 (NLSy1) galaxy. Our spectroscopic campaign will allow us to study the spectroscopic properties (FWHM, EW, flux) of broad-emission lines in the optical (e.g. H{\\beta}) and mid-UV (e.g. Mg II {\\lambda}2800) regimes, depending on the redshift of the source. The cadence of the broad emission lines monitoring is about five nights per month which in turn will permit us to explore whether there is a correlated variability between broad emission line features and high levels of {\\gamma}-ray emission.

  5. Beam position monitor data acquisition for the Advanced Photon Source

    Energy Technology Data Exchange (ETDEWEB)

    Lenkszus, F.R.; Kahana, E.; Votaw, A.J.; Decker, G.A.; Chung, Y.; Ciarlette, D.J.; Laird, R.J.

    1993-01-01

    This paper describes the Beam Position Monitor (BPM) data acquisition scheme for the Advanced Photon Source (APS) storage ring. The storage ring contains 360 beam position monitors distributed around its 1104-meter circumference. The beam position monitor data acquisition system is capable of making turn-by-turn measurements of all BPMs simultaneously. It is VXI-based with each VXI crate containing the electronics for 9 BPMS. The VXI Local Bus is used to provide sustained data transfer rates of up to 13 mega-transfers per second to a scanner module. The system provides single-bunch tracking, bunch-to-bunch measurements, fast digital-averaged positions, beam position history buffering, and synchronized multi-turn measurements. Data is accessible to the control system VME crates via an MXI bus. Dedicated high-speed ports are provided to supply position data to beam orbit feedback systems.

  6. Beam position monitor data acquisition for the Advanced Photon Source

    Energy Technology Data Exchange (ETDEWEB)

    Lenkszus, F.R.; Kahana, E.; Votaw, A.J.; Decker, G.A.; Chung, Y.; Ciarlette, D.J.; Laird, R.J.

    1993-06-01

    This paper describes the Beam Position Monitor (BPM) data acquisition scheme for the Advanced Photon Source (APS) storage ring. The storage ring contains 360 beam position monitors distributed around its 1104-meter circumference. The beam position monitor data acquisition system is capable of making turn-by-turn measurements of all BPMs simultaneously. It is VXI-based with each VXI crate containing the electronics for 9 BPMS. The VXI Local Bus is used to provide sustained data transfer rates of up to 13 mega-transfers per second to a scanner module. The system provides single-bunch tracking, bunch-to-bunch measurements, fast digital-averaged positions, beam position history buffering, and synchronized multi-turn measurements. Data is accessible to the control system VME crates via an MXI bus. Dedicated high-speed ports are provided to supply position data to beam orbit feedback systems.

  7. A new, efficient laser source at 630 nm for photodynamic therapy and pulsed hologram

    Energy Technology Data Exchange (ETDEWEB)

    Azzeer, Abdallah M.; Masilamani, Vadivel [King Saud University, College of Science, Riyadh (Saudi Arabia)

    2003-02-01

    This paper gives details of a new, simple and efficient laser source at 630 nm with an average power of 300 mW, based on stimulated Raman scattering (SRS) from an organic liquid, and with the second harmonic of a Nd:YAG laser as a pump source. What we have developed here can be fabricated as a module that can be added to a Nd:YAG laser, commonly available in laser clinics, for an effective photodynamic therapy (PDT) of caner. The same source would become a convenient tool for a pulsed hologram. (author)

  8. Performance of a reflectometer at continuous wave and pulsed neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    Fitzsimmons, M.R. [Los Alamos National Laboratory, NM (United States)

    1995-12-31

    The Monte-Carlo simulations presented here involve simulations of reflectivity measurements of one sample using a reflectometer of traditional geometry at different neutron sources. The same reflectometer was used in all simulations. Only the characteristics of the neutron source, and the technique used to measure neutron wavelength were changed. In the case of the CW simulation, a monochromating crystal was used to select a nearly monochromatic beam (MB) from the neutron spectrum. In the simulations of the pulse sources, the time needed to traverse a fixed distance was measured, from which neutron wavelength is deduced.

  9. Toward Ubiquitous Blood Pressure Monitoring via Pulse Transit Time: Theory and Practice.

    Science.gov (United States)

    Mukkamala, Ramakrishna; Hahn, Jin-Oh; Inan, Omer T; Mestha, Lalit K; Kim, Chang-Sei; Töreyin, Hakan; Kyal, Survi

    2015-08-01

    Ubiquitous blood pressure (BP) monitoring is needed to improve hypertension detection and control and is becoming feasible due to recent technological advances such as in wearable sensing. Pulse transit time (PTT) represents a well-known potential approach for ubiquitous BP monitoring. The goal of this review is to facilitate the achievement of reliable ubiquitous BP monitoring via PTT. We explain the conventional BP measurement methods and their limitations; present models to summarize the theory of the PTT-BP relationship; outline the approach while pinpointing the key challenges; overview the previous work toward putting the theory to practice; make suggestions for best practice and future research; and discuss realistic expectations for the approach.

  10. A high flux pulsed source of energetic atomic oxygen. [for spacecraft materials ground testing

    Science.gov (United States)

    Krech, Robert H.; Caledonia, George E.

    1986-01-01

    The design and demonstration of a pulsed high flux source of nearly monoenergetic atomic oxygen are reported. In the present test setup, molecular oxygen under several atmospheres of pressure is introduced into an evacuated supersonic expansion nozzle through a pulsed molecular beam valve. A 10J CO2 TEA laser is focused to intensities greater than 10 to the 9th W/sq cm in the nozzle throat, generating a laser-induced breakdown with a resulting 20,000-K plasma. Plasma expansion is confined by the nozzle geometry to promote rapid electron-ion recombination. Average O-atom beam velocities from 5-13 km/s at fluxes up to 10 to the 18th atoms/pulse are measured, and a similar surface oxygen enrichment in polyethylene samples to that obtained on the STS-8 mission is found.

  11. Ultrafast X-ray Science at the Sub-Picosecond Pulse Source

    Energy Technology Data Exchange (ETDEWEB)

    Gaffney, Kelly J.; /SLAC, SSRL

    2005-09-30

    The ultrafast, high brightness x-ray free electron laser (XFEL) sources of the future have the potential to revolutionize the study of time dependent phenomena in the natural sciences. These linear accelerator (linac) sources will generate femtosecond (fs) x-ray pulses with peak flux comparable to conventional lasers, and far exceeding all other x-ray sources. The Stanford Linear Accelerator Center (SLAC) has pioneered the development of linac science and technology for decades, and since 2000 SLAC and the Stanford Synchrotron Radiation Laboratory (SSRL) have focused on the development of linac based ultrafast electron and x-ray sources. This development effort has led to the creation of a new x-ray source, called the Sub-Picosecond Pulse Source (SPPS), which became operational in 2003 [1]. The SPPS represents the first step toward the world's first hard x-ray free electron laser (XFEL), the Linac Coherent Light Source (LCLS), due to begin operation at SLAC in 2009. The SPPS relies on the same linac-based acceleration and electron bunch compression schemes that will be used at the LCLS to generate ultrashort, ultrahigh peak brightness electron bunches [2]. This involves creating an energy chirp on the electron bunch during acceleration and subsequent compression of the bunch in a series of energy-dispersive magnetic chicanes to create 80 fs electron pulses. The SPPS has provided an excellent opportunity to demonstrate the viability of these electron bunch compression schemes and to pursue goals relevant to the utilization and validation of XFEL light sources.

  12. Monte Carlo modeling and analyses of YALINA- booster subcritical assembly Part II : pulsed neutron source.

    Energy Technology Data Exchange (ETDEWEB)

    Talamo, A.; Gohar, M. Y. A.; Rabiti, C.; Nuclear Engineering Division

    2008-10-22

    One of the most reliable experimental methods for measuring the kinetic parameters of a subcritical assembly is the Sjoestrand method applied to the reaction rate generated from a pulsed neutron source. This study developed a new analytical methodology for characterizing the kinetic parameters of a subcritical assembly using the Sjoestrand method, which allows comparing the analytical and experimental time dependent reaction rates and the reactivity measurements. In this methodology, the reaction rate, detector response, is calculated due to a single neutron pulse using MCNP/MCNPX computer code or any other neutron transport code that explicitly simulates the fission delayed neutrons. The calculation simulates a single neutron pulse over a long time period until the delayed neutron contribution to the reaction is vanished. The obtained reaction rate is superimposed to itself, with respect to the time, to simulate the repeated pulse operation until the asymptotic level of the reaction rate, set by the delayed neutrons, is achieved. The superimposition of the pulse to itself was calculated by a simple C computer program. A parallel version of the C program is used due to the large amount of data being processed, e.g. by the Message Passing Interface (MPI). The new calculation methodology has shown an excellent agreement with the experimental results available from the YALINA-Booster facility of Belarus. The facility has been driven by a Deuterium-Deuterium or Deuterium-Tritium pulsed neutron source and the (n,p) reaction rate has been experimentally measured by a {sup 3}He detector. The MCNP calculation has utilized the weight window and delayed neutron biasing variance reduction techniques since the detector volume is small compared to the assembly volume. Finally, this methodology was used to calculate the IAEA benchmark of the YALINA-Booster experiment.

  13. Experiments on the Pulsed Afterglow Operation of an ECR Ion Source

    CERN Document Server

    Hill, C

    1999-01-01

    Various experiments have been performed on the 14.5 GHz ECR4 in order to improve the beam yield. The source operates in pulsed "afterglow" mode, and provides currents >120 emA of Pb27+ to the Heavy Ion Facility on an operational basis. In the search for higher beam intensities, the effects of a pulsed biased disk on axis at the injection side were investigated with different pulse timing and voltage settings. Different plasma electrode geometries were also tested, including running the source without a plasma electrode. The use of CF4 as mixing gas was investigated, and high secondary electron emission materials, such as LaB6 and Al2O3, were inserted inside the plasma chamber in an attempt to increase the cold electron density. No proof for higher intensities was seen for any of the tested modifications. On the contrary, several of the modifications resulted in lower source performance, and less stability. Although the source has previously proved to have very stable modes of operation, during the last physic...

  14. Linear Track Estimation Using Double Pulse Sources for Near-Field Underwater Moving Target

    Institute of Scientific and Technical Information of China (English)

    Zhifei Chen; Hong Hou; Jianhua Yang; Jincai Sun; Qian Wang

    2013-01-01

    The double pulse sources (DPS) method is presented for linear track estimation in this work.In the field of noise identification of underwater moving target,the Doppler will distort the frequency and amplitude of the radiated noise.To eliminate this,the track estimation is necessary.In the DPS method,we first estimate bearings of two sinusoidal pulse sources installed in the moving target through baseline positioning method.Meanwhile,the emitted and recorded time of each pulse are also acquired.Then the linear track parameters will be achieved based on the geometry pattern with the help of double sources spacing.The simulated results confirm that the DPS improves the performance of the previous double source spacing method.The simulated experiments were carried out using a moving battery car to further evaluate its performance.When the target is 40-60m away,the experiment results show that biases of track azimuth and abeam distance of DPS are under 0.6° and 3.4m,respectively.And the average deviation of estimated velocity is around 0.25m/s.

  15. Application of Pressure Pulse Test Analysis in CO2 Leakage Detection and Monitoring

    Science.gov (United States)

    Shakiba, M.; Hosseini, S. A.

    2015-12-01

    Over the past decade, numerous research and industrial projects have been devoted to investigate the feasibility and efficiency of carbon dioxide capture, storage, and utilization. Besides the studies over the characteristics of candidate formations for CO2 injection, much attention has been paid to answer the environmental concerns regarding the CO2 leak to overlying formations. To first detect and then track a possible CO2 leak, different techniques have been proposed in the literature; however, most of them examine only a small portion of the formation and have a low resolution for early leak detection. To further increase the extent of the investigation zone and to monitor a large section of the formation in more detail, multi-well testing techniques have received a significant attention. Pressure pulse testing is a multi-well test technique in which a pressure signal generated by periods of injection and shut-in from a pulser well is propagated inside the formation, and the corresponding response is recorded at the observer wells. The recorded pressure response is then analyzed to measure the rock and fluid properties and to monitor the possible changes over the time. In this research study, we have applied frequency methods as well as superposition principle to interpret the pressure pulse test data and monitor the changes in transmissibility and storativity of the formation between the well pairs. We have used synthetic reservoir models and numerical reservoir simulations to produce the pressure pulse test data. The analysis of the simulation results indicated that even a small amount of CO2 leak in the investigation zone can have a measurable effect on the calculated storativity and transmissibility factors. This can be of a great importance when an early leak detection is of interest. Moreover, when multiple wells are available in the formation, the distribution of the calculated parameters can visualize the extent of CO2 leak, which has a great

  16. Pulsed-terahertz reflectometry for health monitoring of ceramic thermal barrier coatings.

    Science.gov (United States)

    Chen, Chia-Chu; Lee, Dong-Joon; Pollock, Tresa; Whitaker, John F

    2010-02-15

    Terahertz time-domain reflectometry was used to monitor the progress of a thermally grown oxide layer and stress-induced, air-filled voids at the interface of an Yttria-stabilized-zirconia ceramic thermal-barrier coating and a metal surface. The thicknesses of these internal layers, observed in scanning-electron-microscope images to increase with thermal-exposure time, have been resolved - even when changing on the order of only a few micrometers - by distinguishing not only increased delays in the arrival times of terahertz pulses reflected from this multilayer structure, but also changes in the width and shape of the pulses. These unique features can be used to predict the lifetime of thermal-barrier coatings and to indicate or warn of spallation conditions. The trends of the experimental results are also confirmed through Fresnel-reflection time-domain simulations.

  17. Plasma Outages in Pulsed, High-Power RF Hydrogen Ion Sources

    Science.gov (United States)

    Stockli, Martin; Han, Baoxi; Murray, Syd; Pennisi, Terry; Piller, Chip; Santana, Manuel; Welton, Robert

    2011-04-01

    Pulsed, high-power RF ion sources are needed to produce copious amounts of negative H-ions for high-power accelerators with charge-changing injection schemes. When increasing the RF power, the plasma inductance changes the RF resonance, which drifts away from the low-power resonance. When the RF circuit is tuned to maximize the (pulsed) plasma power, the (off-resonance) power at the beginning of the pulse is reduced. If the induced electric fields fall below the breakdown strength of the hydrogen gas, the plasma fails to develop. This can be avoided with a compromise tune and/or by increasing the inductance of the resonant circuit. However, the breakdown strength of the hydrogen gas increases with time due to the gradual decrease of the electron-rich plasma impurities, which causes plasma outages after weeks of reliable operation. In this paper we discuss the success of different mitigations that were tested and implemented to overcome this fundamental problem of pulsed, high-power RF hydrogen ion sources.

  18. Discriminating non-seismic long-period pulses and noise to improve earthquake source inversion

    Science.gov (United States)

    Sakai, Takahide; Kumagai, Hiroyuki; Pulido, Nelson; Bonita, Jun; Nakano, Masaru

    2016-04-01

    Broadband seismometers produce artifacts resembling long-period pulses (non-seismic pulses) that degrade centroid moment tensor (CMT) estimations based on waveform inversion of broadband seismic records in long-period bands (50-200 s). We propose a method to discriminate non-seismic pulses and long-period noise from seismic signals, which can be applied to automatic CMT inversion analysis. In this method, we calculate source amplitudes as peak-to-peak displacement amplitudes in individual long-period seismic records after each event has been corrected for medium attenuation and geometric spreading and then estimate the ratios of individual source amplitudes to the minimum source amplitude. Because source amplitude ratios for non-seismic pulses tend to be greater than those of the seismic signals, we use seismic records in CMT estimations only if their source amplitude ratios are lower than a threshold value ( R). We tested this method using broadband seismic data from the Philippines and found that reprocessed inversion solutions using this method showed a clear improvement when using R = 11, although focal mechanism estimations were not entirely stable. To investigate the general applicability of this method, we analyzed broadband seismic data from F-net in Japan. Our analysis indicated that source amplitude ratios in F-net data ranged up to about 20, indicating that the threshold value may be dependent on station density. Given that F-net is one of the highest density networks in the world, we may assume that a threshold value between 10 and 20 is appropriate for application of our method for most regional broadband networks. Our synthetic tests indicated that source amplitude ratios can be as high as 103, although observed ratios are only within the range 10-20. This suggests that we happened to observe only events having focal mechanisms with source amplitude ratios of 10-20. Alternatively, these high source amplitude ratios can be explained by distortion of

  19. Interconnected High-Voltage Pulsed-Power Converters System Design for H− Ion Sources

    CERN Document Server

    Aguglia, D

    2014-01-01

    This paper presents the design and experimental validations of a system of three new high-voltage (HV) pulsedpower converters for the H− sources. The system requires three pulsed voltages (50, 40, and 25 kV to ground) at 2-Hz repetition rate, for 700 μs of usable flat-top. The solution presents ripplefree output voltages and minimal stored energy to protect the ion source from the consequences of arc events. Experimental results on the final full-scale prototype are presented. In case of short-circuit events, the maximal energy delivered to the source is in the Joule range. HV flat-top stability of 1% is experimentally achieved with a simple Proportional-Integral- Derivative regulation and preliminary tuned H− source (e.g., radio frequency control, gas injection, and so forth). The system is running since more than a year with no power converter failures and damage to the source.

  20. Optimising a muon spectrometer for measurements at the ISIS pulsed muon source

    Energy Technology Data Exchange (ETDEWEB)

    Giblin, S.R. [ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX (United Kingdom); School of Physics and Astronomy, Cardiff University, Cardiff CF24 3AA (United Kingdom); Cottrell, S.P., E-mail: stephen.cottrell@stfc.ac.uk [ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX (United Kingdom); King, P.J.C.; Tomlinson, S.; Jago, S.J.S.; Randall, L.J.; Roberts, M.J.; Norris, J.; Howarth, S.; Mutamba, Q.B.; Rhodes, N.J.; Akeroyd, F.A. [ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX (United Kingdom)

    2014-07-01

    This work describes the development of a state-of-the-art muon spectrometer for the ISIS pulsed muon source. Conceived as a major upgrade of the highly successful EMU instrument, emphasis has been placed on making effective use of the enhanced flux now available at the ISIS source. This has been achieved both through the development of a highly segmented detector array and enhanced data acquisition electronics. The pulsed nature of the ISIS beam is particularly suited to the development of novel experiments involving external stimuli, and therefore the ability to sequence external equipment has been added to the acquisition system. Finally, the opportunity has also been taken to improve both the magnetic field and temperature range provided by the spectrometer, to better equip the instrument for running the future ISIS user programme.

  1. Performance of the solid deuterium ultra-cold neutron source at the pulsed reactor TRIGA Mainz

    CERN Document Server

    Karch, J; Beck, M; Eberhardt, K; Hampel, G; Heil, W; Kieser, R; Reich, T; Trautmann, N; Ziegner, M

    2013-01-01

    The performance of the solid deuterium ultra-cold neutron source at the pulsed reactor TRIGA Mainz with a maximum peak energy of 10 MJ is described. The solid deuterium converter with a volume of V=160 cm3 (8 mol), which is exposed to a thermal neutron fluence of 4.5x10^13 n/cm2, delivers up to 550 000 UCN per pulse outside of the biological shield at the experimental area. UCN densities of ~ 10/cm3 are obtained in stainless steel bottles of V ~ 10 L resulting in a storage efficiency of ~20%. The measured UCN yields compare well with the predictions from a Monte Carlo simulation developed to model the source and to optimize its performance for the upcoming upgrade of the TRIGA Mainz into a user facility for UCN physics.

  2. Variable Voltage Source Inverter with controlled frequency spectrum based on Random Pulse Width Modulation

    Directory of Open Access Journals (Sweden)

    Muhammad Farrukh Yaqub

    2012-01-01

    Full Text Available This paper presents a new method for single phase variable voltage inverter based on Random Pulse Width Modulation. In Random Pulse Width Modulation based inverter, the frequency spectrum of the output current and voltage waveforms becomes continuous because of the randomization of the switching function of the devices controlling the output voltages. This paper establishes a theory that if the distributions of the random numbers generated by the random source are kept within certain limit with respect to the peak value of reference sinusoidal waveform, the frequency spectrum can be controlled. On the basis of the results, a novel drive using variable tap changing transformer (optional and adaptive random number generator, to control the ratio between the numbers generated by the random source and the reference waveform has been suggested that will guarantee a better power quality profile for a broad range of output voltages.

  3. Unconstrained pulse pressure monitoring for health management using hetero-core fiber optic sensor.

    Science.gov (United States)

    Nishiyama, Michiko; Sonobe, Masako; Watanabe, Kazuhiro

    2016-09-01

    In this paper, we present a pulse pressure waveform sensor that does not constrain a wearer's daily activity; the sensor uses hetero-core fiber optics. Hetero-core fiber sensors have been found to be sensitive to moderate bending. To detect minute pulse pressure changes from the radial artery at the wrist, we devised a fiber sensor arrangement using three-point bending supports. We analyzed and evaluated the measurement validity using wavelet transformation, which is well-suited for biological signal processing. It was confirmed that the detected pulse waveform had a fundamental mode frequency of around 1.25 Hz over the time-varying waveform. A band-pass filter with a range of frequencies from 0.85 to 1.7 Hz was used to pick up the fundamental mode. In addition, a high-pass filter with 0.85 Hz frequency eliminated arm motion artifacts; consequently, we achieved high signal-to-noise ratio. For unrestricted daily health management, it is desirable that pulse pressure monitoring can be achieved by simply placing a device on the hand without the sensor being noticed. Two types of arrangements were developed and demonstrated in which the pulse sensors were either embedded in a base, such as an armrest, or in a wearable device. A wearable device without cuff pressure using a sensitivity-enhanced fiber sensor was successfully achieved with a sensitivity of 0.07-0.3 dB with a noise floor lower than 0.01 dB for multiple subjects.

  4. Optimization of native fluorescence detection of proteins using a pulsed nano laser excitation source

    OpenAIRE

    Heywood, Matthew S.; Farnsworth, Paul B.

    2010-01-01

    We present a mathematical description of the S/N ratio in a fluorescence-based protein detector for capillary electrophoresis that uses a pulsed UV laser at 266 nm as an excitation source. The model accounts for photobleaching, detector volume, laser repetition rate, and analyte flow rate. We have experimentally characterized such a system, and present a comparison of the experimental data with the predictions of the model. Using the model, the system was optimized for test analytes tryptopha...

  5. An atmospheric pressure plasma source driven by a train of monopolar high voltage pulses superimposed to a dc voltage

    OpenAIRE

    Stoican, O.S.

    2011-01-01

    Abstract An atmospheric pressure plasma source supplied by an electrical circuit consisting of two voltage sources in parallel connection is reported. One of them is a low-power self-oscillating flyback converter which produces negative voltage pulses with an amplitude of several kilovolts. The high voltage pulses are necessary to ignite an electrical discharge between the electrodes at atmospheric pressure. An additional dc source delivering several hundreds of volts at a few hund...

  6. Sources of Quasi-Periodic Pulses in the 18 August 2012 Flare

    CERN Document Server

    Altyntsev, A; Meszarosova, H; Karlicky, M; Palshin, V; Lesovoi, S

    2016-01-01

    We analyzed spatial and spectral characteristics of quasi-periodic pulses (QPP) for the 18 August 2012 limb are, using new data from a complex of spectral and imaging instruments developed by the Siberian Solar Radio Telescope team and the Wind/Konus gamma-ray spectrometer. A sequence of broadband pulses with periods of approximately ten seconds were observed in X-rays at energies between 25 keV and 300 keV, and in microwaves at frequencies from a few GHz up to 34 GHz during an interval of one minute. The QPP X-ray source was located slightly above the limb where the south legs of large and small EUV loop systems were close to each other. Before the QPPs the soft X-ray emission and the Ramaty High Energy Solar Spectroscopic Imager signal from the energy channels below 25 keV were gradually arising for several minutes at the same location. It was found that each X-ray pulse showed the soft-hard-soft behavior. The 17 and 34 GHz microwave source were at footpoints of the small loop system and the source emitting...

  7. Development of source range measurement instrument in Xi'an pulsed reactor

    CERN Document Server

    Wang Li

    2002-01-01

    Source range measurement instrument in Xi'an pulsed reactor is key equipment of low-side measuring in source range. At the same time, it is also weighty component of out-of-pile neutron-flux level observation system. The authors have done some researching and renovating based on the similar type devices used in nuclear reactor to improve the meter sensitivity, measuring range, noise proof features, reliability in running and maintainability which belong to the main performance index of the instrument. The design ideas, configurations, working principle, performance indexes, technique features and effect in utilizing are introduced briefly

  8. Development of ion source with a washer gun for pulsed neutral beam injection.

    Science.gov (United States)

    Asai, T; Yamaguchi, N; Kajiya, H; Takahashi, T; Imanaka, H; Takase, Y; Ono, Y; Sato, K N

    2008-06-01

    A new type of economical neutral beam source has been developed by using a single washer gun, pulsed operation, and a simple electrode system. We replaced the conventional hot filaments for arc-discharge-type plasma formation with a single stainless-steel washer gun, eliminating the entire dc power supply for the filaments and the cooling system for the electrodes. Our initial experiments revealed successful beam extraction up to 10 kV and 8.6 A, based on spatial profile measurements of density and temperature in the plasma source. The system also shows the potential to control the beam profile by controlling the plasma parameters in the ion accumulation chamber.

  9. An all-fiber source of pulsed twin beams at telecom band for quantum communication

    CERN Document Server

    Guo, Xueshi; Liu, Nannan; Yang, Lei; Ou, Z Y

    2012-01-01

    Motivated by the pursuit of a simple system to produce non-classical light sources for long- distance quantum communication, we generate for the first time an all-fiber source of pulsed twin beams in 1550 nm band by using a high gain fiber optical parametric amplifier. The noise of intensity difference of the twin beams is below the shot noise limit by 3.1 dB (10.4 dB after correction for losses). A detailed study reveals a number of limiting factors for higher noise reduction. Therefore, further noise reduction will be feasible once care is taken for these limiting factors.

  10. Development of terminal hair following skin lesion treatments with an intense pulsed light source.

    Science.gov (United States)

    Vlachos, Spiros P; Kontoes, Paraskevas P

    2002-01-01

    Laser and other light sources have been used to treat vascular and pigmented skin lesions and to remove tattoos and unwanted hair, with varying degrees of success and various side effects. It has not yet been reported that hair growth can occur as a side effect of such treatments. In this paper two cases are presented, one port wine stain and one tattoo, that were each treated several times with an intense pulsed light source (IPLS) for removal. Terminal hair, not present before treatment, partially developed in treated areas of both lesions. Local inflammatory reactions are believed to trigger such outcomes.

  11. Thermal-hydraulic simulation of mercury target concepts for a pulsed spallation neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Siman-Tov, M.; Wendel, M.; Haines, J. [Oak Ridge National Lab., TN (United States)

    1996-06-01

    The Oak Ridge Spallation Neutron Source (ORSNS) is a high-power, accelerator-based pulsed spallation neutron source being designed by a multi-laboratory team led by Oak Ridge National Laboratory to achieve very high fluxes of neutrons for scientific experiments. The ORSNS is projected to have a 1 MW proton beam upgradable to 5 MW. About 60% of the beam power (1-5 MW, 17-83 kJ/pulse in 0.5 microsec at 60 cps) is deposited in the liquid metal (mercury) target having the dimensions of 65x30x10 cm (about 19.5 liter). Peak steady state power density is about 150 and 785 MW/m{sup 3} for 1 MW and 5 MW beam respectively, whereas peak pulsed power density is as high as 5.2 and 26.1 GW/m{sup 3}, respectively. The peak pulse temperature rise rate is 14 million C/s (for 5 MW beam) whereas the total pulse temperature rise is only 7 C. In addition to thermal shock and materials compatibility, key feasibility issues for the target are related to its thermal-hydraulic performance. This includes proper flow distribution, flow reversals, possible {open_quotes}hot spots{close_quotes} and the challenge of mitigating the effects of thermal shock through possible injection of helium bubbles throughout the mercury volume or other concepts. The general computational fluid dynamics (CFD) code CFDS-FLOW3D was used to simulate the thermal and flow distribution in three preliminary concepts of the mercury target. Very initial CFD simulation of He bubbles injection demonstrates some potential for simulating behavior of He bubbles in flowing mercury. Much study and development will be required to be able to `predict`, even in a crude way, such a complex phenomena. Future direction in both design and R&D is outlined.

  12. High power visible light emitting diodes as pulsed excitation sources for biomedical photoacoustics.

    Science.gov (United States)

    Allen, Thomas J; Beard, Paul C

    2016-04-01

    The use of visible light emitting diodes (LEDs) as an alternative to Q-switched lasers conventionally used as photoacoustic excitation sources has been explored. In common with laser diodes, LEDs offer the advantages of compact size, low cost and high efficiency. However, laser diodes suitable for pulsed photoacoustic generation are typically available only at wavelengths greater than 750nm. By contrast, LEDs are readily available at visible wavelengths below 650nm where haemoglobin absorption is significantly higher, offering the prospect of increased SNR for superficial vascular imaging applications. To demonstrate feasibility, a range of low cost commercially available LEDs operating in the 420-620nm spectral range were used to generate photoacoustic signals in physiologically realistic vascular phantoms. Overdriving with 200ns pulses and operating at a low duty cycle enabled pulse energies up to 10µJ to be obtained with a 620nm LED. By operating at a high pulse repetition frequency (PRF) in order to rapidly signal average over many acquisitions, this pulse energy was sufficient to generate detectable signals in a blood filled tube immersed in an Intralipid suspension (µs' = 1mm(-1)) at a depth of 15mm using widefield illumination. In addition, a compact four-wavelength LED (460nm, 530nm, 590nm, 620nm) in conjunction with a coded excitation scheme was used to illustrate rapid multiwavelength signal acquisition for spectroscopic applications. This study demonstrates that LEDs could find application as inexpensive and compact multiwavelength photoacoustic excitation sources for imaging superficial vascular anatomy. Published by The Optical Society under the terms of the Creative Commons Attribution 4.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

  13. Parallel plate chambers for monitoring the profiles of high-intensity pulsed antiproton beams

    CERN Document Server

    Hori, Masaki

    2004-01-01

    Two types of beam profile monitor with thin parallel-plate electrodes have been used in experiments carried out at the Low Energy Antiproton Ring (LEAR) and Antiproton Decelerator (AD) of CERN. The detectors were used to measure non-destructively the spatial profiles, absolute intensities, and time structures of 100-300-ns- long beam pulses containing between 10**7 and 10**9 antiprotons. The first of these monitors was a parallel plate ionization chamber operated at gas pressure P=65 mbar. The other was a secondary electron emission detector, and was operated in the ultra-high vacuum of the AD. Both designs may be useful in medical and commercial applications. The position-sensitive electrodes in these detectors were manufactured by a novel method in which a laser trimmer was used to cut strip patterns on metallized polyester foils.

  14. Imaging pulse wave velocity in mouse retina using swept-source OCT (Conference Presentation)

    Science.gov (United States)

    Song, Shaozhen; Wei, Wei; Wang, Ruikang K.

    2016-03-01

    Blood vessel dynamics has been a significant subject in cardiology and internal medicine, and pulse wave velocity (PWV) on artery vessels is a classic evaluation of arterial distensibility, and has never been ascertained as a cardiovascular risk marker. The aim of this study is to develop a high speed imaging technique to capture the pulsatile motion on mouse retina arteries with the ability to quantify PWV on any arterial vessels. We demonstrate a new non-invasive method to assess the vessel dynamics on mouse retina. A Swept-source optical coherence tomography (SS-OCT) system is used for imaging micro-scale blood vessel motion. The phase-stabilized SS-OCT provides a typical displacement sensitivity of 20 nm. The frame rate of imaging is ~16 kHz, at A-line rate of ~1.62 MHz, which allows the detection of transient pulse waves with adequate temporal resolution. Imaging volumes with repeated B-scans are obtained on mouse retina capillary bed, and the mouse oxymeter signal is recorded simultaneously. The pulse wave on artery and vein are resolved, and with the synchronized heart beat signal, the temporal delay on different vessel locations is determined. The vessel specific measurement of PWV is achieved for the first time with SS-OCT, for pulse waves propagating more than 100 cm/s. Using the novel methodology of retinal PWV assessment, it is hoped that the clinical OCT scans can provide extended diagnostic information of cardiology functionalities.

  15. Neutronics of a poisoned para-hydrogen moderator for a pulsed spallation neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Harada, Masahide [Neutron Facility Group, Quantum Beam Science Directorate, Japan Atomic Energy Agency, Tokai-mura, Naka-gun, Ibaraki-ken 319 1195 (Japan)]. E-mail: harada.masahide@jaea.go.jp; Watanabe, Noboru [Neutron Facility Group, Quantum Beam Science Directorate, Japan Atomic Energy Agency, Tokai-mura, Naka-gun, Ibaraki-ken 319 1195 (Japan); Teshigawara, Makoto [Neutron Facility Group, Quantum Beam Science Directorate, Japan Atomic Energy Agency, Tokai-mura, Naka-gun, Ibaraki-ken 319 1195 (Japan); Kai, Tetsuya [Neutron Facility Group, Quantum Beam Science Directorate, Japan Atomic Energy Agency, Tokai-mura, Naka-gun, Ibaraki-ken 319 1195 (Japan); Kato, Takashi [Neutron Facility Group, Quantum Beam Science Directorate, Japan Atomic Energy Agency, Tokai-mura, Naka-gun, Ibaraki-ken 319 1195 (Japan); Ikeda, Yujiro [Neutron Facility Group, Quantum Beam Science Directorate, Japan Atomic Energy Agency, Tokai-mura, Naka-gun, Ibaraki-ken 319 1195 (Japan)

    2007-05-11

    Neutronic performance of a poisoned hydrogen moderator was studied in details. Using a simple rectangular-shape moderator-model, its basic characteristics were studied as a function of the poison position. We, for the first time, turned up that the pulse width was rather decreasing with increasing the moderator thickness of the back part from the poison. This is due to the fact that source neutron pulses entering into a front part of the poison through the back part exhibit a fast rise shape while those from the target and the reflector through the decoupler and liner exhibit a broad shape. Next, we studied the pulse deterioration in regard to a finite beam-extraction-angle by using a more realistic moderator shape, canteen shape and a concave-shape. It turns out that the pulse deterioration is considerably large in both cases even at a small extraction angle. The concave-shape moderator indicates a finite improvement compared to the canteen-shape one. Finally, merits and demerits of two poison materials, Cadmium and Gadolinium, were discussed taking into account the burn-up issue of poison with the operation time.

  16. Numerical modeling of the intracavity stimulated Raman scattering as a source of subnanosecond optical pulses

    Science.gov (United States)

    Yashkir, Yuri M.; Yashkir, Yuriy Y.

    2004-09-01

    We present a computer numerical model (virtual sub-nanosecond laser) utilizing intracavity stimulated Raman scattering. The goal of this work is to shorten laser output pulses (for which the highly nonlinear frequency conversion process stimulated Raman scattering is used) and to obtain high efficiency (which is enhanced by placing a Raman-active crystal inside the cavity where the fundamental laser frequency intensity is maximal). The following laser components were modeled: a diodepumped solidstate laser active medium (a crystal of the Nd3+:YLF type), a closed cavity for a wave on its fundamental frequency with a Q-switching element and an internal subcavity with a Ramanactive crystal with controlled output coupler transmission at the Raman frequency. The model components are: a numerical integrator of a set of three rate equations (for an inverse population of the laser medium and for the number of fundamental and Stokes frequency photons), random number sources for radiation seeding, and an interactive data input interface and graphic output. A wide range of parameters was investigated and output pulses as short as 0.8 ns were found. The optimal conditions for the maximal peak power of Stokes pulses were determined and the conditions for generating pulse trains for burst laser machining were identified.

  17. Effect of source parameters on forward-directivity velocity pulse for vertical strike slip fault in half space

    Institute of Scientific and Technical Information of China (English)

    Liu Qifang; Yuan Yifan; Jin Xing

    2006-01-01

    It has been found that the large velocity pulse is one of the most important characteristics of near-fault strong ground motions. Some statistical relationships between pulse period and the moment magnitude for near-fault strong ground motions have been established by Somerville (1998); Alavi and Krawinkler ( 2000); and Mavroeidis and Papageorgiou (2003), where no variety of rupture velocity, fault depth, and fault distance, etc. were considered. Since near-fault ground motions are significantly influenced by the rupture process and source parameters, the effects of some source parameters on the amplitude and the period of a forward-directivity velocity pulse in a half space are analyzed by the finite difference method combined with the kinematic source model in this paper. The study shows that the rupture velocity, fault depth, position of the initial rupture point and distribution of asperities are the most important parameters to the velocity pulse. Generally, the pulse period decreases and the pulse amplitude increases as the rupture velocity increases for shallow crustal earthquakes. In a definite region besides the fault trace, the pulse period increases as the fault depth increases. For a uniform strike slip fault,rupture initiating from one end of a fault and propagating to the other always generates a higher pulse amplitude and longer pulse period than in other cases.

  18. Effect of source parameters on forward-directivity velocity pulse for vertical strike slip fault in half space

    Science.gov (United States)

    Liu, Qifang; Yuan, Yifan; Jin, Xing

    2006-06-01

    It has been found that the large velocity pulse is one of the most important characteristics of near-fault strong ground motions. Some statistical relationships between pulse period and the moment magnitude for near-fault strong ground motions have been established by Somerville (1998); Alavi and Krawinkler (2000); and Mavroeidis and Papageorgiou (2003), where no variety of rupture velocity, fault depth, and fault distance, etc. were considered. Since near-fault ground motions are significantly influenced by the rupture process and source parameters, the effects of some source parameters on the amplitude and the period of a forward-directivity velocity pulse in a half space are analyzed by the finite difference method combined with the kinematic source model in this paper. The study shows that the rupture velocity, fault depth, position of the initial rupture point and distribution of asperities are the most important parameters to the velocity pulse. Generally, the pulse period decreases and the pulse amplitude increases as the rupture velocity increases for shallow crustal earthquakes. In a definite region besides the fault trace, the pulse period increases as the fault depth increases. For a uniform strike slip fault, rupture initiating from one end of a fault and propagating to the other always generates a higher pulse amplitude and longer pulse period than in other cases.

  19. Monitoring of transient cavitation induced by ultrasound and intense pulsed light in presence of gold nanoparticles.

    Science.gov (United States)

    Sazgarnia, Ameneh; Shanei, Ahmad; Shanei, Mohammad Mahdi

    2014-01-01

    One of the most important challenges in medical treatment is invention of a minimally invasive approach in order to induce lethal damages to cancer cells. Application of high intensity focused ultrasound can be beneficial to achieve this goal via the cavitation process. Existence of the particles and vapor in a liquid decreases the ultrasonic intensity threshold required for cavitation onset. In this study, synergism of intense pulsed light (IPL) and gold nanoparticles (GNPs) has been investigated as a means of providing nucleation sites for acoustic cavitation. Several approaches have been reported with the aim of cavitation monitoring. We conducted the experiments on the basis of sonochemiluminescence (SCL) and chemical dosimetric methods. The acoustic cavitation activity was investigated by determining the integrated SCL signal acquired over polyacrylamide gel phantoms containing luminol in the presence and absence of GNPs in the wavelength range of 400-500 nm using a spectrometer equipped with cooled charged coupled devices (CCD) during irradiation by different intensities of 1 MHz ultrasound and IPL pulses. In order to confirm these results, the terephthalic acid chemical dosimeter was utilized as well. The SCL signal recorded in the gel phantoms containing GNPs at different intensities of ultrasound in the presence of intense pulsed light was higher than the gel phantoms without GNPs. These results have been confirmed by the obtained data from the chemical dosimetry method. Acoustic cavitation in the presence of GNPs and intense pulsed light has been suggested as a new approach designed for decreasing threshold intensity of acoustic cavitation and improving targeted therapeutic effects. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. Monitoring alert and drowsy states by modeling EEG source nonstationarity

    Science.gov (United States)

    Hsu, Sheng-Hsiou; Jung, Tzyy-Ping

    2017-10-01

    Objective. As a human brain performs various cognitive functions within ever-changing environments, states of the brain characterized by recorded brain activities such as electroencephalogram (EEG) are inevitably nonstationary. The challenges of analyzing the nonstationary EEG signals include finding neurocognitive sources that underlie different brain states and using EEG data to quantitatively assess the state changes. Approach. This study hypothesizes that brain activities under different states, e.g. levels of alertness, can be modeled as distinct compositions of statistically independent sources using independent component analysis (ICA). This study presents a framework to quantitatively assess the EEG source nonstationarity and estimate levels of alertness. The framework was tested against EEG data collected from 10 subjects performing a sustained-attention task in a driving simulator. Main results. Empirical results illustrate that EEG signals under alert versus drowsy states, indexed by reaction speeds to driving challenges, can be characterized by distinct ICA models. By quantifying the goodness-of-fit of each ICA model to the EEG data using the model deviation index (MDI), we found that MDIs were significantly correlated with the reaction speeds (r  =  ‑0.390 with alertness models and r  =  0.449 with drowsiness models) and the opposite correlations indicated that the two models accounted for sources in the alert and drowsy states, respectively. Based on the observed source nonstationarity, this study also proposes an online framework using a subject-specific ICA model trained with an initial (alert) state to track the level of alertness. For classification of alert against drowsy states, the proposed online framework achieved an averaged area-under-curve of 0.745 and compared favorably with a classic power-based approach. Significance. This ICA-based framework provides a new way to study changes of brain states and can be applied to

  1. Miniaturized pulsed laser source for time-domain diffuse optics routes to wearable devices

    Science.gov (United States)

    Di Sieno, Laura; Nissinen, Jan; Hallman, Lauri; Martinenghi, Edoardo; Contini, Davide; Pifferi, Antonio; Kostamovaara, Juha; Mora, Alberto Dalla

    2017-08-01

    We validate a miniaturized pulsed laser source for use in time-domain (TD) diffuse optics, following rigorous and shared protocols for performance assessment of this class of devices. This compact source (12×6 mm2) has been previously developed for range finding applications and is able to provide short, high energy (˜100 ps, ˜0.5 nJ) optical pulses at up to 1 MHz repetition rate. Here, we start with a basic level laser characterization with an analysis of suitability of this laser for the diffuse optics application. Then, we present a TD optical system using this source and its performances in both recovering optical properties of tissue-mimicking homogeneous phantoms and in detecting localized absorption perturbations. Finally, as a proof of concept of in vivo application, we demonstrate that the system is able to detect hemodynamic changes occurring in the arm of healthy volunteers during a venous occlusion. Squeezing the laser source in a small footprint removes a key technological bottleneck that has hampered so far the realization of a miniaturized TD diffuse optics system, able to compete with already assessed continuous-wave devices in terms of size and cost, but with wider performance potentialities, as demonstrated by research over the last two decades.

  2. Counter-facing plasma focus system as an efficient and long-pulse EUV light source

    Science.gov (United States)

    Kuwabara, H.; Hayashi, K.; Kuroda, Y.; Nose, H.; Hotozuka, K.; Nakajima, M.; Horioka, K.

    2011-04-01

    A plasma focus system composed of a pair of counter-facing coaxial plasma guns is proposed as a long-pulse and efficient EUV light source. A proof-of-concept experiment demonstrated that with an assist of breakdown and outer electrode connections, current sheets evolved into a configuration for stable plasma confinement at the center of the electrode. The current sheets could successively compress and confine the high energy density plasma every half period of the discharge current, enabling highly repetitive light emissions in extreme ultraviolet region with time duration in at least ten microseconds for Xe plasma. Also, we confirmed operations of our system for Li plasma. We estimated the highest EUV energy in Li plasma operation at 93mJ/4π sr per 2% bandwidth per pulse.

  3. The new high field photoexcitation muon spectrometer at the ISIS pulsed neutron and muon source

    CERN Document Server

    Yokoyama, K; Murahari, P; Wang, K; Dunstan, D J; Waller, S P; McPhail, D J; Hillier, A D; Henson, J; Harper, M R; Heathcote, P; Drew, A J

    2016-01-01

    A high power pulsed laser system has been installed on the high magnetic field muon instrument (HiFi) at the ISIS pulsed neutron and muon source, situated at the STFC Rutherford Appleton Laboratory in the UK. The upgrade enables one to perform light-pump muon-probe experiments under a high field, which opens up a brand-new area in the muon spin spectroscopy. In this report we overview the principle of the HiFi Laser system, and describe the newly developed techniques and devices that enable a controlled photoexcitation in the muon instrument. A demonstration experiment illustrates the unique combination of the photoexcited system and avoided level crossing technique.

  4. Cyclinac medical accelerators using pulsed C6+/H2+ ion sources

    Science.gov (United States)

    Garonna, A.; Amaldi, U.; Bonomi, R.; Campo, D.; Degiovanni, A.; Garlasché, M.; Mondino, I.; Rizzoglio, V.; Verdú Andrés, S.

    2010-09-01

    Charged particle therapy, or so-called hadrontherapy, is developing very rapidly. There is large pressure on the scientific community to deliver dedicated accelerators, providing the best possible treatment modalities at the lowest cost. In this context, the Italian research Foundation TERA is developing fast-cycling accelerators, dubbed `cyclinacs'. These are a combination of a cyclotron (accelerating ions to a fixed initial energy) followed by a high gradient linac boosting the ions energy up to the maximum needed for medical therapy. The linac is powered by many independently controlled klystrons to vary the beam energy from one pulse to the next. This accelerator is best suited to treat moving organs with a 4D multipainting spot scanning technique. A dual proton/carbon ion cyclinac is here presented. It consists of an Electron Beam Ion Source, a superconducting isochronous cyclotron and a high-gradient linac. All these machines are pulsed at high repetition rate (100-400 Hz). The source should deliver both C6+ and H2+ ions in short pulses (1.5 μs flat-top) and with sufficient intensity (at least 108 fully stripped carbon ions per pulse at 300 Hz). The cyclotron accelerates the ions to 120 MeV/u. It features a compact design (with superconducting coils) and a low power consumption. The linac has a novel C-band high-gradient structure and accelerates the ions to variable energies up to 400 MeV/u. High RF frequencies lead to power consumptions which are much lower than the ones of synchrotrons for the same ion extraction energy. This work is part of a collaboration with the CLIC group, which is working at CERN on high-gradient electron-positron colliders.

  5. Source properties of dynamic rupture pulses with off-fault plasticity

    KAUST Repository

    Gabriel, A.-A.

    2013-08-01

    Large dynamic stresses near earthquake rupture fronts may induce an inelastic response of the surrounding materials, leading to increased energy absorption that may affect dynamic rupture. We systematically investigate the effects of off-fault plastic energy dissipation in 2-D in-plane dynamic rupture simulations under velocity-and-state-dependent friction with severe weakening at high slip velocity. We find that plasticity does not alter the nature of the transitions between different rupture styles (decaying versus growing, pulse-like versus crack-like, and subshear versus supershear ruptures) but increases their required background stress and nucleation size. We systematically quantify the effect of amplitude and orientation of background shear stresses on the asymptotic properties of self-similar pulse-like ruptures: peak slip rate, rupture speed, healing front speed, slip gradient, and the relative contribution of plastic strain to seismic moment. Peak slip velocity and rupture speed remain bounded. From fracture mechanics arguments, we derive a nonlinear relation between their limiting values, appropriate also for crack-like and supershear ruptures. At low background stress, plasticity turns self-similar pulses into steady state pulses, for which plastic strain contributes significantly to the seismic moment. We find that the closeness to failure of the background stress state is an adequate predictor of rupture speed for relatively slow events. Our proposed relations between state of stress and earthquake source properties in the presence of off-fault plasticity may contribute to the improved interpretation of earthquake observations and to pseudodynamic source modeling for ground motion prediction.

  6. Cyclinac medical accelerators using pulsed C{sup 6+}/H{sub 2}{sup +} ion sources

    Energy Technology Data Exchange (ETDEWEB)

    Garonna, A; Amaldi, U; Bonomi, R; Campo, D; Degiovanni, A; Garlasche, M; Mondino, I; Rizzoglio, V; Andres, S Verdu, E-mail: Adriano.Garonna@cern.c [TERA Foundation, via G. Puccini 11, 28100 Novara (Italy)

    2010-09-15

    Charged particle therapy, or so-called hadrontherapy, is developing very rapidly. There is large pressure on the scientific community to deliver dedicated accelerators, providing the best possible treatment modalities at the lowest cost. In this context, the Italian research Foundation TERA is developing fast-cycling accelerators, dubbed 'cyclinacs'. These are a combination of a cyclotron (accelerating ions to a fixed initial energy) followed by a high gradient linac boosting the ions energy up to the maximum needed for medical therapy. The linac is powered by many independently controlled klystrons to vary the beam energy from one pulse to the next. This accelerator is best suited to treat moving organs with a 4D multipainting spot scanning technique. A dual proton/carbon ion cyclinac is here presented. It consists of an Electron Beam Ion Source, a superconducting isochronous cyclotron and a high-gradient linac. All these machines are pulsed at high repetition rate (100-400 Hz). The source should deliver both C{sup 6+} and H{sub 2}{sup +} ions in short pulses (1.5 {mu}s flat-top) and with sufficient intensity (at least 10{sup 8} fully stripped carbon ions per pulse at 300 Hz). The cyclotron accelerates the ions to 120 MeV/u. It features a compact design (with superconducting coils) and a low power consumption. The linac has a novel C-band high-gradient structure and accelerates the ions to variable energies up to 400 MeV/u. High RF frequencies lead to power consumptions which are much lower than the ones of synchrotrons for the same ion extraction energy. This work is part of a collaboration with the CLIC group, which is working at CERN on high-gradient electron-positron colliders.

  7. Correction: Spectroscopic characteristics of the OSIRIS near-backscattering crystal analyser spectrometer on the ISIS pulsed neutron source.

    Science.gov (United States)

    Telling, Mark T F; Campbell, Stuart I; Engberg, Dennis; Martín Y Marero, David; Andersen, Ken H

    2016-03-21

    Correction for 'Spectroscopic characteristics of the OSIRIS near-backscattering crystal analyser spectrometer on the ISIS pulsed neutron source' by Mark T. F. Telling et al., Phys. Chem. Chem. Phys., 2005, 7, 1255-1261.

  8. 40 CFR 141.402 - Ground water source microbial monitoring and analytical methods.

    Science.gov (United States)

    2010-07-01

    ... Rule § 141.402 Ground water source microbial monitoring and analytical methods. (a) Triggered source water monitoring—(1) General requirements. A ground water system must conduct triggered source water... State, systems must submit for State approval a triggered source water monitoring plan that identifies...

  9. A Volt-Second Source for Calibration of Integrator in a Pulsed Field Magnetometer

    Institute of Scientific and Technical Information of China (English)

    LIN An-Li; HE Jian; ZHANG Yue; John Dudding; Michael Hall

    2007-01-01

    A volt-second (Vs) source intended for absolutely calibrating the integrator in a pulsed field magnetometer (PFM) is designed and proven to be with accurate rising and falling edges and reasonable lower uncertainty. A comparison experiment shows that the difference between the magnetic fluxes generated respectively by the Vs source and the mutual inductor is within ±0.04%. The PFM is then calibrated in an absolute way of the Vs source. The calibrated PFM gives the measured results in good agreement with a static BH tracer supplied by National Institute of Metrology of China and provides a convenient way of studying the effect of mathematic process on the dynamic measuring curve of PFMs.

  10. ECR-driven multicusp H^- volume source operated in pulsed or cw mode

    Science.gov (United States)

    Svarnas, Panayiotis

    2005-10-01

    Electron cyclotron resonance (ECR) driven multicusp H^- volume hybrid source [1, 2] operates in continuous (cw) or pulsed microwave (2.45 GHz) mode up to 3 kW. The hydrogen plasma is produced between 1 and 7 mTorr by seven elementary ECR sources housed in the magnetic multipole chamber ``Camembert III'' [3]. This ECR configuration could be applied both to accelerator and fusion ion sources. Negative ion or electron extracted currents and plasma characteristics are studied in both modes with electrical measurements, electrostatic probe and photodetachment. The role of the plasma electrode bias in the values of the extracted currents is major. H^- current is maximized for a bias voltage close to plasma potential. An optimum pressure at 4-5 mTorr yields enhanced H^- density in the center of the chamber, under cw regime. Finally, the post-discharge formation of H^-, in the pulsed mode, is observed. [1] A.A. Ivanov Jr., C. Rouille, M. Bacal, Y. Arnal, S. Bechu, J. Pelletier, Rev. Sci. Instrum. 75(5), 1750 (2004) [2] M. Bacal, A.A. Ivanov Jr., C. Rouille, P. Svarnas, S. Bechu, J. Pelletier, AIP Conf. Proc. No 763 (Kiev, Ukraine) (2004) [3] C. Courteille, A.M. Bruneteau, M. Bacal, Rev. Sci. Instrum. 66(3), 2533 (1995)

  11. Design and characterization of the annular cathode high current pulsed electron beam source for circular components

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-08-01

    Highlights: • An annular cathode for HCPEB irradiation of circular components was designed. • The processing window for the annular cathode is obtained. • Irradiation thickness uniformity along the circumferential direction exceeds 90%. - Abstract: In order to irradiate circular components with high current pulsed electron beam (HCPEB), an annular cathode based on carbon fiber bunches was designed and fabricated. Using an acceleration voltage of 25 kV, the maximum pulsed irradiation current and energy of this annular cathode can reach 7.9 kA and 300 J, respectively. The irradiation current density distribution of the annular cathode HCPEB source measured along the circumferential direction shows that the annular cathode has good emission uniformity. In addition, four 9310 steel substrates fixed uniformly along the circumferential direction of a metal ring substrate were irradiated by this annular cathode HCPEB source. The surface and cross-section morphologies of the irradiated samples were characterized by scanning electron microscopy (SEM). SEM images of the surface reveal that crater and surface undulation have been formed, which hints that the irradiation energy of the HCPEB process is large enough for surface modification of 9310 steel. Meanwhile, SEM cross-section images exhibit that remelted layers with a thickness of about 5.4 μm have been obtained in all samples, which proves that a good practical irradiation uniformity can be achieved by this annular cathode HCPEB source.

  12. Short-Pulse Limits in Optical Instrumentation Design for the SLAC Linac Coherent Light Source (LCLS)

    Energy Technology Data Exchange (ETDEWEB)

    Tatchyn, R.

    2005-01-31

    The source properties of linac-driven X-Ray Free-Electron Lasers (XRFELs) operating in the Self-Amplified Spontaneous Emission (SASE) regime differ markedly from those of ordinary insertion devices on synchrotron storage rings. In the case of the 1.5 {angstrom} SLAC Linac Coherent Light Source (LCLS), the longitudinal output profile typically consists of a randomly-distributed train of fully-transversely-coherent micropulses of randomly varying intensity and an average length (corresponding to the source coherence length) two to three orders of magnitude smaller than the transverse diameter of the beam. Total pulse lengths are typically of the same order of size as the beam diameter. Both of these properties can be shown to significantly impact the performance of otherwise conventional synchrotron radiation optics; viz., mirrors, lenses, zone plates, crystals, multilayers, etc. In this paper we outline an analysis of short-pulse effects on selected optical components for the SLAC LCLS and discuss the implications for critical applications such as microfocusing and monochromatization.

  13. Electron-volt spectroscopy at a pulsed neutron source using a resonance detector technique

    CERN Document Server

    Andreani, C; Senesi, R; Gorini, G; Tardocchi, M; Bracco, A; Rhodes, N; Schooneveld, E M

    2002-01-01

    The effectiveness of the neutron resonance detector spectrometer for deep inelastic neutron scattering measurements has been assessed by measuring the Pb scattering on the eVS spectrometer at ISIS pulsed neutron source and natural U foils as (n,gamma) resonance converters. A conventional NaI scintillator with massive shielding has been used as gamma detector. A neutron energy window up to 90 eV, including four distinct resonance peaks, has been assessed. A net decrease of the intrinsic width of the 6.6 eV resonance peak has also been demonstrated employing the double difference spectrum technique, with two uranium foils of different thickness.

  14. a Chirped-Pulse Fourier Transform Microwave Spectrometer Combined with a Laser Ablation Source

    Science.gov (United States)

    Mata, S.; Pena, I.; Cabezas, C.; López, J. C.; Alonso, J. L.; Pate, B. H.

    2011-06-01

    The design of a chirped-pulse Fourier transform microwave spectrometer CP-FTMW combined with a laser ablation LA source is presented. The spectrometer is capable of measuring the 6.5-18 GHz region. Rotational spectra of solid samples of proline (m.p. 228° C) and alanine (m.p. 290° C) vaporized by laser ablation has been recorded. Four low-energy conformers of proline and two in alanine have been detected. 13C species of alanine in their natural abundance have been also observed. The performance of this spectrometer is compared to a LA-MB-FTMW spectrometer.

  15. MHD generators as pulse power sources for arc-driven railguns

    Energy Technology Data Exchange (ETDEWEB)

    Esposito, N.; Raugi, M.; Tellini, A. [Univ. di Pisa (Italy). Dipt. di Sistemi Elettrici e Automazione

    1995-01-01

    In this paper the performances of an electromagnetic launch system constituted by an arc driven railgun powered by a MHD generator are investigated. A small bore plasma driven railgun for fusion fuel pellet injection is examined considering as pulse power source a MHD generator having characteristics taken from operating devices. The analysis of the railgun and generator has been carried out by means of a lumped parameter equivalent network model that takes into account drag force and ablation effects and allowing the evaluation of the main electrical and thermodynamic quantity distributions of the plasma arc.

  16. Data acquisition system for the neutron scattering instruments at the intense pulsed neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, R.K.; Daly, R.T.; Haumann, J.R.; Hitterman, R.L.; Morgan, C.B.; Ostrowski, G.E.; Worlton, T.G.

    1981-01-01

    The Intense Pulsed Neutron Source (IPNS) at Argonne National Laboratory is a major new user-oriented facility which is now coming on line for basic research in neutron scattering and neutron radiation damage. This paper describes the data-acquisition system which will handle data acquisition and instrument control for the time-of-flight neutron-scattering instruments at IPNS. This discussion covers the scientific and operational requirements for this system, and the system architecture that was chosen to satisfy these requirements. It also provides an overview of the current system implementation including brief descriptions of the hardware and software which have been developed.

  17. Kinetic instabilities in pulsed operation mode of a 14 GHz electron cyclotron resonance ion source

    Energy Technology Data Exchange (ETDEWEB)

    Tarvainen, O., E-mail: olli.tarvainen@jyu.fi; Kalvas, T.; Koivisto, H.; Komppula, J.; Kronholm, R.; Laulainen, J. [Department of Physics, University of Jyväskylä, 40500 Jyväskylä (Finland); Izotov, I.; Mansfeld, D. [Institute of Applied Physics, RAS, 46 Ul‘yanova St., 603950 Nizhny Novgorod (Russian Federation); Skalyga, V. [Institute of Applied Physics, RAS, 46 Ul‘yanova St., 603950 Nizhny Novgorod (Russian Federation); Lobachevsky State University of Nizhny Novgorod (UNN), 23 Gagarina St., 603950 Nizhny Novgorod (Russian Federation)

    2016-02-15

    The occurrence of kinetic plasma instabilities is studied in pulsed operation mode of a 14 GHz A-electron cyclotron resonance type electron cyclotron resonance ion source. It is shown that the temporal delay between the plasma breakdown and the appearance of the instabilities is on the order of 10-100 ms. The most important parameters affecting the delay are magnetic field strength and neutral gas pressure. It is demonstrated that kinetic instabilities limit the high charge state ion beam production in the unstable operating regime.

  18. A Guillemin type E pulse forming network as the driver for a pulsed, high density plasma source.

    Science.gov (United States)

    Rathod, Priyavandna J; Anitha, V P; Sholapurwala, Z H; Saxena, Y C

    2014-06-01

    A Guillemin type E pulse forming network (PFN) has been designed, developed, and tested for its application in generating high density (~1 × 10(18) m(-3)) plasmas. In the present study, plasma thus generated is utilized to investigate the interaction of high power microwaves (HPMs) with plasma in an experimental architecture known as SYMPLE (System for Microwave PLasma Experiment). Plasma discharges of ~100 μs (max) duration are to be produced, by delivering energy of 5 kJ stored in a PFN to the plasma source, a washer gun. The output of the PFN, in terms of its rise time, flat top and amplitude, needs to be tailored, depending on the experimental requirements. An ignitron (NL8900) trigger generator (ITG) is developed in-house to control the PFN discharge through the gun. This ITG is also to be used in a circuit that synchronizes the HPM and plasma shots, to ensure that HPM-plasma interaction takes place during a temporal regime where appropriate parametric conditions are satisfied. Hence it is necessary to retain the jitter within ±2.5 μs. Further, requirement on plasma quiescence (~10%) necessitates maintaining the ripple within 5%. The developmental work of the PFN, keeping in view the above criteria and the test results, is presented in this paper. The parameters of the PFN have been analytically approximated and verified with PSPICE simulation. The test results presented include rise time ~5-8 μs, flat top variable in the range 20-100 μs, ripple within ~1.5%, and jitter within ±2.5 μs, producing quiescent (plasma discharge meeting the experimental requirements.

  19. Characterisation of flash X-ray source generated by Kali-1000 Pulse Power System

    Science.gov (United States)

    Satyanarayana, N.; Durga Prasada Rao, A.; Mittal, K. C.

    2016-02-01

    The electron beam-driven Rod Pinch Diode (RPD) is presently fielded on KALI-1000 Pulse Power System at Bhabha Atomic Research Centre, Visakhapatnam and is a leading candidate for future flash X-ray radiographic sources. The diode is capable of producing less than 2-mm radiation spot sizes and greater than 350 milli rads of dose measured at 1 m from the X-ray source. KALI-1000 Pulse Power Source is capable of delivering up to 600 kV using a Tesla Transformer with Demineralized Insulated Transmission Line (DITL), the diode typically operates between 250-330 kV . Since the radiation dose has a power-law dependence on diode voltage, this limits the dose production on KALI-1000 system. Radiation dose with angular variation is measured using thermoluminescent detectors (TLD's) and the X-ray spot size is measured using pin hole arrangement with image plate (IP) to obtain the time-integrated source profile as well as a time-resolved spot diagnostic. An X-ray pinhole camera was used to pick out where the energetic e-beam connects to the anode. Ideally the diode should function such that the radiation is emitted from the tip. The camera was mounted perpendicular to the machine's axis to view the radiation from the tip. Comparison of the spot sizes of the X-ray sources obtained by the pin hole and rolled edge arrangements was carried and results obtained by both the techniques are with in ± 10% of the average values.

  20. Dual-modality arterial pulse monitoring system for continuous blood pressure measurement.

    Science.gov (United States)

    Wen-Xuan Dai; Yuan-Ting Zhang; Jing Liu; Xiao-Rong Ding; Ni Zhao

    2016-08-01

    Accurate and ambulatory measurement of blood pressure (BP) is essential for efficient diagnosis, management and prevention of cardiovascular diseases (CVDs). However, traditional cuff-based BP measurement methods provide only intermittent BP readings and can cause discomfort with the occlusive cuff. Although pulse transit time (PTT) method is promising for cuffless and continuous BP measurement, its pervasive use is restricted by its limited accuracy and requirement of placing sensors on multiple body sites. To tackle these issues, we propose a novel dual-modality arterial pulse monitoring system for continuous blood pressure measurement, which simultaneously records the pressure and photoplethysmography (PPG) signals of radial artery. The obtained signals can be used to generate a pressure-volume curve, from which the elasticity index (EI) and viscosity index (VI) can be extracted. Experiments were carried out among 7 healthy subjects with their PPG, ECG, arterial pressure wave and reference BP collected to examine the effectiveness of the proposed indexes. The results of this study demonstrate that a linear regression model combining EI and VI has significantly higher BP tracking correlation coefficient as compared to the PTT method. This suggests that the proposed system and method can potentially be used for convenient and continuous blood pressure estimation with higher accuracy.

  1. Control Scheme of Z-Source Inverter Based BLDC Motor Drive System Using Modified Pulse Width Modulation Techniq

    Directory of Open Access Journals (Sweden)

    S. Suresh Kumar,

    2014-01-01

    Full Text Available A modified pulse width modulation technique for Z-source inverter based BLDC motor is proposed and analyzed in this project.The Z-source inverter can be used as Buck/Boost converter with lower cost and high efficiency. BLDC motors are used in electric vehicles where portability and efficiency are required. This drive system provides advantages of both BLDC motors and Z-source inverter, and can be used in fuel cell system and other adjustable speed drive application. In this project principle of modified pulse width modulation technique is implemented and simulated. The model of a three phase Z-source inverter has been discussed based on modified pulse with modulation technique. The simulation of Z-source inverter based BLDC motor is done using the MATLAB/SIMULINK.

  2. Automatic algorithm for monitoring systolic pressure variation and difference in pulse pressure.

    Science.gov (United States)

    Pestel, Gunther; Fukui, Kimiko; Hartwich, Volker; Schumacher, Peter M; Vogt, Andreas; Hiltebrand, Luzius B; Kurz, Andrea; Fujita, Yoshihisa; Inderbitzin, Daniel; Leibundgut, Daniel

    2009-06-01

    Difference in pulse pressure (dPP) reliably predicts fluid responsiveness in patients. We have developed a respiratory variation (RV) monitoring device (RV monitor), which continuously records both airway pressure and arterial blood pressure (ABP). We compared the RV monitor measurements with manual dPP measurements. ABP and airway pressure (PAW) from 24 patients were recorded. Data were fed to the RV monitor to calculate dPP and systolic pressure variation in two different ways: (a) considering both ABP and PAW (RV algorithm) and (b) ABP only (RV(slim) algorithm). Additionally, ABP and PAW were recorded intraoperatively in 10-min intervals for later calculation of dPP by manual assessment. Interobserver variability was determined. Manual dPP assessments were used for comparison with automated measurements. To estimate the importance of the PAW signal, RV(slim) measurements were compared with RV measurements. For the 24 patients, 174 measurements (6-10 per patient) were recorded. Six observers assessed dPP manually in the first 8 patients (10-min interval, 53 measurements); no interobserver variability occurred using a computer-assisted method. Bland-Altman analysis showed acceptable bias and limits of agreement of the 2 automated methods compared with the manual method (RV: -0.33% +/- 8.72% and RV(slim): -1.74% +/- 7.97%). The difference between RV measurements and RV(slim) measurements is small (bias -1.05%, limits of agreement 5.67%). Measurements of the automated device are comparable with measurements obtained by human observers, who use a computer-assisted method. The importance of the PAW signal is questionable.

  3. Pulsed-laser micropatterned quantum-dot array for white light source

    Science.gov (United States)

    Wang, Sheng-Wen; Lin, Huang-Yu; Lin, Chien-Chung; Kao, Tsung Sheng; Chen, Kuo-Ju; Han, Hau-Vei; Li, Jie-Ru; Lee, Po-Tsung; Chen, Huang-Ming; Hong, Ming-Hui; Kuo, Hao-Chung

    2016-03-01

    In this study, a novel photoluminescent quantum dots device with laser-processed microscale patterns has been demonstrated to be used as a white light emitting source. The pulsed laser ablation technique was employed to directly fabricate microscale square holes with nano-ripple structures onto the sapphire substrate of a flip-chip blue light-emitting diode, confining sprayed quantum dots into well-defined areas and eliminating the coffee ring effect. The electroluminescence characterizations showed that the white light emission from the developed photoluminescent quantum-dot light-emitting diode exhibits stable emission at different driving currents. With a flexibility of controlling the quantum dots proportions in the patterned square holes, our developed white-light emitting source not only can be employed in the display applications with color triangle enlarged by 47% compared with the NTSC standard, but also provide the great potential in future lighting industry with the correlated color temperature continuously changed in a wide range.

  4. Frequency-time coherence for all-optical sampling without optical pulse source

    Science.gov (United States)

    Preußler, Stefan; Raoof Mehrpoor, Gilda; Schneider, Thomas

    2016-09-01

    Sampling is the first step to convert an analogue optical signal into a digital electrical signal. The latter can be further processed and analysed by well-known electrical signal processing methods. Optical pulse sources like mode-locked lasers are commonly incorporated for all-optical sampling, but have several drawbacks. A novel approach for a simple all-optical sampling is to utilise the frequency-time coherence of each signal. The method is based on only using two coupled modulators driven with an electrical sine wave. Since no optical source is required, a simple integration in appropriate platforms, such as Silicon Photonics might be possible. The presented method grants all-optical sampling with electrically tunable bandwidth, repetition rate and time shift.

  5. Novel high peak current pulsed diode laser sources for direct material processing

    Science.gov (United States)

    Traub, M.; Bock, M.; Hoffmann, H.-D.; Bartram, M.

    2007-02-01

    Diode laser systems are well established for applications which demand high continuous wave (cw) power. These applications are material processing like cutting and welding of metals as well as polymers where diode laser systems are less expensive and more compact than solid state lasers. Even though the optical output power and the beam quality of diode lasers are increasing steadily, the use of these sources is generally limited to cw applications. For processes during which ablating of material is demanded, however, conventional diode lasers are inferior compared to pulsed solid state lasers as diode lasers suffer from the absence of optical intracavity q-switching. Some examples of these applications are coating removal and marking. To overcome this drawback, we have developed several diode laser systems that use high peak-current drivers and thereby allow to operate the diode lasers at currents up to 500 A. The pulse source was tested with fiber coupled single emitters, conventional diode lasers and customized AR-coated diode laser bars. With the new diode laser driver, a peak output power of 250 W can be achieved with pulse durations of approx. 100 ns. Polarization coupling of two bars increases the power by a factor of two. Thereby an output power of 500 W can be demonstrated. These systems reach an intensity of 27 MW/cm2 per diode laser bar which is sufficient for ablating processes. We will demonstrate the design of the prototype system as well as results of marking and coating removal experiments with the system.

  6. Cyclinac Medical Accelerators Using Pulsed C6+/H2+ Ion Sources

    CERN Document Server

    Garonna, A; Bonomi, R; Campo, D; Degiovanni, A; Garlasché, M; Mondino, I; Rizzoglio, V; Andrés, S Verdú

    2010-01-01

    Charged particle therapy, or so-called hadrontherapy, is developing very rapidly. There is huge pressure on the scientific community to deliver dedicated accelerators, providing the best possible treatment modalities at the lowest cost. In this context, the Italian Research Foundation TERA is developing fast-cycling accelerators, dubbed cyclinacs. These are a combination of a cyclotron (accelerating ions to a fixed initial energy) followed by a high gradient linac boosting the ions energy up to the maximum needed for medical therapy. The linac is powered by many independently controlled klystrons to vary the beam energy from one pulse to the next. This accelerator is best suited to treat moving organs with a 4D multi-painting spot scanning technique. A dual proton/carbon ion cyclinac is here presented. It consists of an Electron Beam Ion Source, a superconducting isochronous cyclotron and a high-gradient linac. All these machines are pulsed at high repetition rate (100-400 Hz). The source should deliver both ...

  7. Multi-Modality Pulsed AC Source for Medical Applications of Non-Equilibrium Plasmas

    Science.gov (United States)

    Friedrichs, Daniel; Gilbert, James

    2014-10-01

    A burgeoning field has developed around the use of non-equilibrium (``cold'') plasmas for various medical applications, including wound treatment, surface sterilization, non-thermal hemostasis, and selective cell destruction. Proposed devices typically utilize pulsed DC power sources, which have no other therapeutic utility, and may encounter significant regulatory restrictions regarding their safety for use in patient care. Additionally, dedicated capital equipment is difficult for healthcare facilities to justify. In this work, we have demonstrated for the first time the generation of non-equilibrium plasma using pulsed AC output from a specially-designed electrosurgical generator. The ability to power novel non-equilibrium plasma devices from a piece of equipment already ubiquitous in operating theatres should significantly reduce the barriers to adoption of plasma devices. We demonstrate the ability of a prototype device, coupled to this source, to reduce bacterial growth in vitro. Such a system could allow a single surgical instrument to provide both non-thermal sterilization and thermal tissue dissection.

  8. Laser-driven electron beam generation for secondary photon sources with few terawatt laser pulses

    Science.gov (United States)

    Bohacek, K.; Chaulagain, U.; Horny, V.; Kozlova, M.; Krus, M.; Nejdl, J.

    2017-05-01

    Relativistic electron beams accelerated by laser wakefield have the ability to serve as sources of collimated, point-like and femtosecond X-ray radiation. Experimental conditions for generation of stable quasi-monoenergetic electron bunches using a femtosecond few-terawatt laser pulse (600 mJ, 50 fs) were investigated as they are crucial for generation of stable betatron radiation and X-ray pulses from inverse Compton scattering. A mixture of helium with argon, and helium with an admixture of synthetic air were tested for this purpose using different backing pressures and the obtained results are compared. The approach to use synthetic air was previously proven to stabilize the energy and energy spread of the generated electron beams at the given laser power. The accelerator was operated in nonlinear regime with forced self-injection and resulted in the generation of stable relativistic electron beams with an energy of tens of MeV and betatron X-ray radiation was generated in the keV range. A razor blade was tested to create a steep density gradient in order to improve the stability of electron injection and to increase the total electron bunch charge. It was proven that the stable electron and X-ray source can be built at small-scale facilities, which readily opens possibilities for various applications due to availability of such few-terawatt laser systems in many laboratories around the world.

  9. Near-source Doppler radar monitoring of tephra plumes at Etna

    Science.gov (United States)

    Donnadieu, F.; Freville, P.; Hervier, C.; Coltelli, M.; Scollo, S.; Prestifilippo, M.; Valade, S.; Rivet, S.; Cacault, P.

    2016-02-01

    Over the last twenty years Mount Etna has produced more than one hundred explosive events ranging from light ash emissions to violent sub-plinian eruptions. Significant hazards arise from tephra plumes which directly threaten air traffic, and generate fallout affecting surrounding towns and infrastructures. We describe the first radar system, named VOLDORAD 2B, fully integrated into a volcano instrumental network dedicated to the continuous near-source monitoring of tephra emissions from Etna's summit craters. This 23.5 cm wavelength pulsed Doppler radar is operated in collaboration between the Observatoire de Physique du Globe de Clermont-Ferrand (OPGC) and the Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Etneo (INGV-OE) since 2009. Probed volumes inside the fixed, northward-pointing conical beam total about 1.5 km in length, covering the summit craters which produced all recent tephra plumes. The backscattered power, related to the amount of particles crossing the beam, and particle along-beam velocities are recorded every 0.23 s, providing a proxy for the tephra mass eruption rate. Radar raw data are transmitted in real-time to the volcano monitoring center of INGV-OE in Catania and are used to automatically release alerts at onset and end of eruptive events. Processed radar parameters are also made available from the VOLDORAD database online.

  10. Effects of nifedipine and ryanodine on adrenergic neurogenic contractions of rat vas deferens: evidence for a pulse-to-pulse change in Ca2+ sources.

    OpenAIRE

    Bültmann, R; von Kügelgen, I; Starke, K

    1993-01-01

    1. The effects of nifedipine and ryanodine on the adrenergic component of neurogenic contractions of the rat isolated vas deferens were studied in an attempt to identify the sources of Ca2+ mediating the contraction. The tissue was electrically stimulated by single pulses or pairs of widely spaced pulses. The purinergic component of contraction was suppressed by the presence of 300 microM suramin. 2. In Mg(2+)-free medium, nifedipine (0.01-10 microM) reduced the first and, to a greater extent...

  11. Neutron imaging with the short-pulse laser driven neutron source at the Trident laser facility

    Science.gov (United States)

    Guler, N.; Volegov, P.; Favalli, A.; Merrill, F. E.; Falk, K.; Jung, D.; Tybo, J. L.; Wilde, C. H.; Croft, S.; Danly, C.; Deppert, O.; Devlin, M.; Fernandez, J.; Gautier, D. C.; Geissel, M.; Haight, R.; Hamilton, C. E.; Hegelich, B. M.; Henzlova, D.; Johnson, R. P.; Schaumann, G.; Schoenberg, K.; Schollmeier, M.; Shimada, T.; Swinhoe, M. T.; Taddeucci, T.; Wender, S. A.; Wurden, G. A.; Roth, M.

    2016-10-01

    Emerging approaches to short-pulse laser-driven neutron production offer a possible gateway to compact, low cost, and intense broad spectrum sources for a wide variety of applications. They are based on energetic ions, driven by an intense short-pulse laser, interacting with a converter material to produce neutrons via breakup and nuclear reactions. Recent experiments performed with the high-contrast laser at the Trident laser facility of Los Alamos National Laboratory have demonstrated a laser-driven ion acceleration mechanism operating in the regime of relativistic transparency, featuring a volumetric laser-plasma interaction. This mechanism is distinct from previously studied ones that accelerate ions at the laser-target surface. The Trident experiments produced an intense beam of deuterons with an energy distribution extending above 100 MeV. This deuteron beam, when directed at a beryllium converter, produces a forward-directed neutron beam with ˜5 × 109 n/sr, in a single laser shot, primarily due to deuteron breakup. The neutron beam has a pulse duration on the order of a few nanoseconds with an energy distribution extending from a few hundreds of keV to almost 80 MeV. For the experiments on neutron-source spot-size measurements, our gated neutron imager was setup to select neutrons in the energy range of 2.5-35 MeV. The spot size of neutron emission at the converter was measured by two different imaging techniques, using a knife-edge and a penumbral aperture, in two different experimental campaigns. The neutron-source spot size is measured ˜1 mm for both experiments. The measurements and analysis reported here give a spatial characterization for this type of neutron source for the first time. In addition, the forward modeling performed provides an empirical estimate of the spatial characteristics of the deuteron ion-beam. These experimental observations, taken together, provide essential yet unique data to benchmark and verify theoretical work into the

  12. Film dosimetry calibration method for pulsed-dose-rate brachytherapy with an 192Ir source.

    Science.gov (United States)

    Schwob, Nathan; Orion, Itzhak

    2007-05-01

    192Ir sources have been widely used in clinical brachytherapy. An important challenge is to perform dosimetric measurements close to the source despite the steep dose gradient. The common, inexpensive silver halide film is a classic two-dimensional integrator dosimeter and would be an attractive solution for these dose measurements. The main disadvantage of film dosimetry is the film response to the low-energy photon. Since the photon energy spectrum is known to vary with depth, the sensitometric curves are expected to be dependent on depth. The purpose of this study is to suggest a correction method for silver halide film dosimetry that overcomes the response changes at different depths. Sensitometric curves have been obtained at different depths with verification film near a 1 Ci 192Ir pulsed-dose-rate source. The depth dependence of the film response was observed and a correction function was established. The suitability of the method was tested through measurement of the radial dose profile and radial dose function. The results were compared to Monte Carlo-simulated values according to the TG43 formalism. Monte Carlo simulations were performed separately for the beta and gamma source emissions, using the EGS4 code system, including the low-energy photon and electron transport optimization procedures. The beta source emission simulation showed that the beta dose contribution could be neglected and therefore the film-depth dependence could not be attributed to this part of the source radioactivity. The gamma source emission simulations included photon-spectra collection at several depths. The results showed a depth-dependent softening of the photon spectrum that can explain the film-energy dependence.

  13. Space Vector Pulse Width Modulation Strategy for Single-Phase Three-Level CIC T-source Inverter

    DEFF Research Database (Denmark)

    Shults, Tatiana E.; Husev, Oleksandr O.; Blaabjerg, Frede

    2016-01-01

    This paper presents a novel space vector pulse-width modulation strategy for a single-phase three-level buck-boost inverter based on an impedance-source network. The case study system is based on T-source inverter with continuous input current. To demonstrate the improved performance of the inver......This paper presents a novel space vector pulse-width modulation strategy for a single-phase three-level buck-boost inverter based on an impedance-source network. The case study system is based on T-source inverter with continuous input current. To demonstrate the improved performance...... of the inverter, the strategy was compared the traditional pulse-width modulation. It is shown that the approach proposed has fewer switching states and does not suffer from neutral point misbalance....

  14. A kinematically beamed, low energy pulsed neutron source for active interrogation

    Science.gov (United States)

    Dietrich, Dan; Hagmann, Chris; Kerr, Phil; Nakae, Les; Rowland, Mark; Snyderman, Neal; Stoeffl, Wolfgang; Hamm, Robert

    2005-12-01

    We are developing a new active interrogation system based on a kinematically focused low energy neutron beam. The key idea is that one of the defining characteristics of special nuclear materials (SNM) is the ability for low energy or thermal neutrons to induce fission. Thus by using low energy neutrons for the interrogation source we can accomplish three goals: (1) energy discrimination allows us to measure the prompt fast fission neutrons produced while the interrogation beam is on; (2) neutrons with an energy of approximately 60-100 keV do not fission 238U and Thorium, but penetrate bulk material nearly as far as high energy neutrons do and (3) below about 100 keV neutrons lose their energy by kinematical collisions rather than via the nuclear (n, 2n) or (n, n‧) processes thus further simplifying the prompt neutron induced background. 60 keV neutrons create a low radiation dose and readily thermal capture in normal materials, thus providing a clean spectroscopic signature of the intervening materials. The kinematically beamed source also eliminates the need for heavy backward and sideway neutron shielding. We have designed and built a very compact pulsed neutron source, based on an RFQ proton accelerator and a lithium target. We are developing fast neutron detectors that are nearly insensitive to the ever-present thermal neutron and neutron capture induced gamma ray background. The detection of only a few high energy fission neutrons in time correlation with the linac pulse will be a clear indication of the presence of SNM.

  15. Design and array signal suggestion of array type pulsed eddy current probe for health monitoring of metal tubes

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Young Kil [Dept. of Electrical Engineering, Kunsan National University, Kunsan (Korea, Republic of)

    2015-10-15

    An array type probe for monitoring metal tubes is proposed in this paper which utilizes peak value and peak time of a pulsed eddy current(PEC) signal. The probe consists of an array of encircling coils along a tube and the outside of coils is shielded by ferrite to prevent source magnetic fields from directly affecting sensor signals since it is the magnetic fields produced by eddy currents that reflect the condition of metal tubes. The positions of both exciter and sensor coils are consecutively moved automatically so that manual scanning is not necessary. At one position of send-receive coils, peak value and peak time are extracted from a sensor PEC signal and these data are accumulated for all positions to form an array type peak value signal and an array type peak time signal. Numerical simulation was performed using the backward difference method in time and the finite element method for spatial analysis. Simulation results showed that peak value increases and the peak appears earlier as the defect depth or length increases. The proposed array signals are shown to be excellent in reflecting the defect location as well as variations of defect depth and length within the array probe.

  16. Compact Short-Pulsed Electron Linac Based Neutron Sources for Precise Nuclear Material Analysis

    Science.gov (United States)

    Uesaka, M.; Tagi, K.; Matsuyama, D.; Fujiwara, T.; Dobashi, K.; Yamamoto, M.; Harada, H.

    2015-10-01

    An X-band (11.424GHz) electron linac as a neutron source for nuclear data study for the melted fuel debris analysis and nuclear security in Fukushima is under development. Originally we developed the linac for Compton scattering X-ray source. Quantitative material analysis and forensics for nuclear security will start several years later after the safe settlement of the accident is established. For the purpose, we should now accumulate more precise nuclear data of U, Pu, etc., especially in epithermal (0.1-10 eV) neutrons. Therefore, we have decided to modify and install the linac in the core space of the experimental nuclear reactor "Yayoi" which is now under the decommission procedure. Due to the compactness of the X-band linac, an electron gun, accelerating tube and other components can be installed in a small space in the core. First we plan to perform the time-of-flight (TOF) transmission measurement for study of total cross sections of the nuclei for 0.1-10 eV energy neutrons. Therefore, if we adopt a TOF line of less than 10m, the o-pulse length of generated neutrons should be shorter than 100 ns. Electronenergy, o-pulse length, power, and neutron yield are ~30 MeV, 100 ns - 1 micros, ~0.4 kW, and ~1011 n/s (~103 n/cm2/s at samples), respectively. Optimization of the design of a neutron target (Ta, W, 238U), TOF line and neutron detector (Ce:LiCAF) of high sensitivity and fast response is underway. We are upgrading the electron gun and a buncher to realize higher current and beam power with a reasonable beam size in order to avoid damage of the neutron target. Although the neutron flux is limited in case of the X-band electron linac based source, we take advantage of its short pulse aspect and availability for nuclear data measurement with a short TOF system. First, we form a tentative configuration in the current experimental room for Compton scattering in 2014. Then, after the decommissioning has been finished, we move it to the "Yayoi" room and perform

  17. Conceptual moderator studies for the Spallation Neutron Source short-pulse second target station

    Science.gov (United States)

    Gallmeier, F. X.; Lu, W.; Riemer, B. W.; Zhao, J. K.; Herwig, K. W.; Robertson, J. L.

    2016-06-01

    Candidate moderator configurations for a short-pulse second target station (STS) at the Oak Ridge National Laboratory Spallation Neutron Source (SNS) have been identified using a global optimizer framework built around the MCNPX particle transport code. Neutron brightness metrics were selected as the figure-of-merit. We assumed that STS would use one out of six proton pulses produced by an SNS accelerator upgraded to operate at 1.3 GeV proton energy, 2.8 MW power and 60 Hz repetition rate. The simulations indicate that the peak brightness can be increased by a factor of 5 and 2.5 on a per proton pulse basis compared to the SNS first target station for both coupled and decoupled para-hydrogen moderators, respectively. Additional increases by factors of 3 and 2 were demonstrated for coupled and decoupled moderators, respectively, by reducing the area of neutron emission from 100 × 100 mm2 to 20 × 20 mm2. This increase in brightness has the potential to translate to an increase of beam intensity at the instruments' sample positions even though the total neutron emission of the smaller moderator is less than that of the larger. This is especially true for instruments with small samples (beam dimensions). The increased fluxes in the STS moderators come at accelerated poison and de-coupler burnout and higher radiation-induced material damage rates per unit power, which overall translate into lower moderator lifetimes. A first effort was undertaken to group decoupled moderators into a cluster collectively positioning them at the peak neutron production zone in the target and having a three-port neutron emission scheme that complements that of a cylindrical coupled moderator.

  18. Conceptual moderator studies for the Spallation Neutron Source short-pulse second target station.

    Science.gov (United States)

    Gallmeier, F X; Lu, W; Riemer, B W; Zhao, J K; Herwig, K W; Robertson, J L

    2016-06-01

    Candidate moderator configurations for a short-pulse second target station (STS) at the Oak Ridge National Laboratory Spallation Neutron Source (SNS) have been identified using a global optimizer framework built around the MCNPX particle transport code. Neutron brightness metrics were selected as the figure-of-merit. We assumed that STS would use one out of six proton pulses produced by an SNS accelerator upgraded to operate at 1.3 GeV proton energy, 2.8 MW power and 60 Hz repetition rate. The simulations indicate that the peak brightness can be increased by a factor of 5 and 2.5 on a per proton pulse basis compared to the SNS first target station for both coupled and decoupled para-hydrogen moderators, respectively. Additional increases by factors of 3 and 2 were demonstrated for coupled and decoupled moderators, respectively, by reducing the area of neutron emission from 100 × 100 mm(2) to 20 × 20 mm(2). This increase in brightness has the potential to translate to an increase of beam intensity at the instruments' sample positions even though the total neutron emission of the smaller moderator is less than that of the larger. This is especially true for instruments with small samples (beam dimensions). The increased fluxes in the STS moderators come at accelerated poison and de-coupler burnout and higher radiation-induced material damage rates per unit power, which overall translate into lower moderator lifetimes. A first effort was undertaken to group decoupled moderators into a cluster collectively positioning them at the peak neutron production zone in the target and having a three-port neutron emission scheme that complements that of a cylindrical coupled moderator.

  19. Conceptual moderator studies for the Spallation Neutron Source short-pulse second target station

    Energy Technology Data Exchange (ETDEWEB)

    Gallmeier, F. X., E-mail: gallmeierfz@ornl.gov; Lu, W.; Riemer, B. W.; Zhao, J. K.; Herwig, K. W.; Robertson, J. L. [Instrument and Source Division, Oak Ridge National Laboratory, P.O. Box 2008, MS6466, Oak Ridge, Tennessee 37831 (United States)

    2016-06-15

    Candidate moderator configurations for a short-pulse second target station (STS) at the Oak Ridge National Laboratory Spallation Neutron Source (SNS) have been identified using a global optimizer framework built around the MCNPX particle transport code. Neutron brightness metrics were selected as the figure-of-merit. We assumed that STS would use one out of six proton pulses produced by an SNS accelerator upgraded to operate at 1.3 GeV proton energy, 2.8 MW power and 60 Hz repetition rate. The simulations indicate that the peak brightness can be increased by a factor of 5 and 2.5 on a per proton pulse basis compared to the SNS first target station for both coupled and decoupled para-hydrogen moderators, respectively. Additional increases by factors of 3 and 2 were demonstrated for coupled and decoupled moderators, respectively, by reducing the area of neutron emission from 100 × 100 mm{sup 2} to 20 × 20 mm{sup 2}. This increase in brightness has the potential to translate to an increase of beam intensity at the instruments’ sample positions even though the total neutron emission of the smaller moderator is less than that of the larger. This is especially true for instruments with small samples (beam dimensions). The increased fluxes in the STS moderators come at accelerated poison and de-coupler burnout and higher radiation-induced material damage rates per unit power, which overall translate into lower moderator lifetimes. A first effort was undertaken to group decoupled moderators into a cluster collectively positioning them at the peak neutron production zone in the target and having a three-port neutron emission scheme that complements that of a cylindrical coupled moderator.

  20. Design of the plasma grid for a short pulse negative ion source experimental setup at HUST

    Science.gov (United States)

    Zuo, C.; Li, D.; Chen, D.; Zhao, P.; Xu, Q.; Liao, Z.

    2017-08-01

    An experimental setup of a radio frequency (RF) driven negative hydrogen ion source has been developed at Huazhong University of Science and Technology (HUST). The setup without cesium oven and an extraction system had been completed and the plasma was ignited in the driver successfully in 2014. An extraction system with small area (5540 mm2) for short pulse (˜ 4 s) was designed to extract the negative hydrogen ions. Generally, the plasma grid temperature is controlled to reach 150 °C by the cooling channels inside the grid. But another method that we could use the PG current to raise the temperature is being considered only for the short pulse condition. An experiment was introduced to prove the feasibility of this method. A magnetic field produced by current flowing through the plasma grid is required to reduce the electron temperature and suppress the co-extraction electrons. The filter field homogeneity has been studied in detail by finite element method. There have been significant improvements regarding the field homogeneity by means of the grid geometry optimization.

  1. Laser-produced plasma He-alpha source for pulse radiography

    Institute of Scientific and Technical Information of China (English)

    Ruirong Wang; Weimin Chen; Chusheng Mao; Jiaqin Dong; Sizu Fu

    2009-01-01

    Through the use of time and space integrated kiloelectronvolt (keV) spectroscopy, we investigate the thermal emission of plasma, which produces strong line emission from the titanium K shell (He-α at 4.7 keV and H-α at 4.9 keV), created by laser. In order to optimize the conversion efficiency enhancement on titanium foils, the experiment is conducted under a variety of laser-driven intensity conditions. The X-ray emission intensity at 4.7 keV is measured and compared with prediction. The experimental result demonstrates that the solid Ti target laser-produced plasma (LPP) source has X-ray emission at 4.7 keV, which are all generated from electronic transitions in Ti ions at pulse width of 2.1 ns or 30 ps, the crudely evaluated He-α X-ray intensity appears to slightly increase with laser intensity enhancement, and the pre-pulse effect increases the conversion efficiency of the He-α X-ray. In addition, a 90-μm-thick Ti foil as a filter is used to transmit He-α X-ray at near 4.7 keV, creating a quasi-monochromatic transmission and greatly reducing thc lower- and higher-energy background.

  2. Measurement of the energy and power radiated by a pulsed blackbody x-ray source

    Directory of Open Access Journals (Sweden)

    H. C. Ives

    2006-11-01

    Full Text Available We have developed a diagnostic system that measures the spectrally integrated (i.e. the total energy and power radiated by a pulsed blackbody x-ray source. The total-energy-and-power (TEP diagnostic system is optimized for blackbody temperatures between 50 and 350 eV. The system can view apertured sources that radiate energies and powers as high as 2 MJ and 200 TW, respectively, and has been successfully tested at 0.84 MJ and 73 TW on the Z pulsed-power accelerator. The TEP system consists of two pinhole arrays, two silicon-diode detectors, and two thin-film nickel bolometers. Each of the two pinhole arrays is paired with a single silicon diode. Each array consists of a 38×38 square array of 10-μm-diameter pinholes in a 50-μm-thick tantalum plate. The arrays achromatically attenuate the x-ray flux by a factor of ∼1800. The use of such arrays for the attenuation of soft x rays was first proposed by Turner and co-workers [Rev. Sci. Instrum. 70, 656 (1999RSINAK0034-674810.1063/1.1149385]. The attenuated flux from each array illuminates its associated diode; the diode’s output current is recorded by a data-acquisition system with 0.6-ns time resolution. The arrays and diodes are located 19 and 24 m from the source, respectively. Because the diodes are designed to have an approximately flat spectral sensitivity, the output current from each diode is proportional to the x-ray power. The nickel bolometers are fielded at a slightly different angle from the array-diode combinations, and view (without pinhole attenuation the same x-ray source. The bolometers measure the total x-ray energy radiated by the source and—on every shot—provide an in situ calibration of the array-diode combinations. Two array-diode pairs and two bolometers are fielded to reduce random uncertainties. An analytic model (which accounts for pinhole-diffraction effects of the sensitivity of an array-diode combination is presented.

  3. Swift-XRT Monitoring of Fermi-LAT Sources of Interest

    Data.gov (United States)

    National Aeronautics and Space Administration — The monitoring data shown on this site provides near real-time results from Swift observations of Fermi-LAT "sources of interest" and flaring sources. While this...

  4. Frequency-time coherence for all-optical sampling without optical pulse source

    CERN Document Server

    Preussler, Stefan; Schneider, Thomas

    2016-01-01

    Sampling is the first step to convert an analogue optical signal into a digital electrical signal. The latter can be further processed and analysed by well-known electrical signal processing methods. Optical pulse sources like mode-locked lasers are commonly incorporated for all-optical sampling, but have several drawbacks. A novel approach for a simple all-optical sampling is to utilise the frequency-time coherence of each signal. The method is based on only using two coupled modulators driven with an electrical sine wave, allowing simple integration in appropriate platforms, such as Silicon Photonics. The presented method grants all-optical sampling with electrically tunable bandwidth, repetition rate and time shift.

  5. Amorphous carbon film deposition on inner surface of tubes using atmospheric pressure pulsed filamentary plasma source

    CERN Document Server

    Pothiraja, Ramasamy; Awakowicz, Peter

    2011-01-01

    Uniform amorphous carbon film is deposited on the inner surface of quartz tube having the inner diameter of 6 mm and the outer diameter of 8 mm. A pulsed filamentary plasma source is used for the deposition. Long plasma filaments (~ 140 mm) as a positive discharge are generated inside the tube in argon with methane admixture. FTIR-ATR, XRD, SEM, LSM and XPS analyses give the conclusion that deposited film is amorphous composed of non-hydrogenated sp2 carbon and hydrogenated sp3 carbon. Plasma is characterized using optical emission spectroscopy, voltage-current measurement, microphotography and numerical simulation. On the basis of observed plasma parameters, the kinetics of the film deposition process is discussed.

  6. Optimization of native fluorescence detection of proteins using a pulsed nanolaser excitation source.

    Science.gov (United States)

    Heywood, Matthew S; Farnsworth, Paul B

    2010-11-01

    We present a mathematical description of the signal-to-noise ratio (S/N) in a fluorescence-based protein detector for capillary electrophoresis that uses a pulsed ultraviolet (UV) laser at 266 nm as an excitation source. The model accounts for photobleaching, detector volume, laser repetition rate, and analyte flow rate. We have experimentally characterized such a system, and we present a comparison of the experimental data with the predictions of the model. Using the model, the system was optimized for test analytes tryptophan, tyrosine, bovine serum albumin (BSA), and conalbumin, producing detection limits (3σ) of 0.67 nM, 5.7 nM, 0.9 nM, and 1.5 nM, respectively. Based on the photobleaching data, a photobleaching cross-section of 1.4 × 10(-18)cm(2) at 266 nm was calculated for tryptophan.

  7. Optimized Controller Design for a 12-Pulse Voltage Source Converter Based HVDC System

    Science.gov (United States)

    Agarwal, Ruchi; Singh, Sanjeev

    2017-08-01

    The paper proposes an optimized controller design scheme for power quality improvement in 12-pulse voltage source converter based high voltage direct current system. The proposed scheme is hybrid combination of golden section search and successive linear search method. The paper aims at reduction of current sensor and optimization of controller. The voltage and current controller parameters are selected for optimization due to its impact on power quality. The proposed algorithm for controller optimizes the objective function which is composed of current harmonic distortion, power factor, and DC voltage ripples. The detailed designs and modeling of the complete system are discussed and its simulation is carried out in MATLAB-Simulink environment. The obtained results are presented to demonstrate the effectiveness of the proposed scheme under different transient conditions such as load perturbation, non-linear load condition, voltage sag condition, and tapped load fault under one phase open condition at both points-of-common coupling.

  8. Status of the Short-Pulse X-ray Project at the Advanced Photon Source

    Energy Technology Data Exchange (ETDEWEB)

    Nassiri, A; Berenc, T G; Borland, M; Brajuskovic, B; Bromberek, D J; Carwardine, J; Decker, G; Emery, L; Fuerst, J D; Grelick, A E; Horan, D; Kaluzny, J; Lenkszus, F; Lill, R M; Liu, J; Ma, H; Sajaev, V; Smith, T L; Stillwell, B K; Waldschmidt, G J; Wu, G; Yang, B X; Yang, Y; Zholents, A; Byrd, J M; Doolittle, L R; Huang, G; Cheng, G; Ciovati, G; Dhakal, P; Eremeev, G V; Feingold, J J; Geng, R L; Henry, J; Kneisel, P; Macha, K; Mammosser, J D; Matalevich, J; Palczewski, A D; Rimmer, R A; Wang, H; Wilson, K M; Wiseman, M; Li, Z

    2012-07-01

    The Advanced Photon Source Upgrade (APS-U) Project at Argonne will include generation of short-pulse x-rays based on Zholents deflecting cavity scheme. We have chosen superconducting (SC) cavities in order to have a continuous train of crabbed bunches and flexibility of operating modes. In collaboration with Jefferson Laboratory, we are prototyping and testing a number of single-cell deflecting cavities and associated auxiliary systems with promising initial results. In collaboration with Lawrence Berkeley National Laboratory, we are working to develop state-of-the-art timing, synchronization, and differential rf phase stability systems that are required for SPX. Collaboration with Advanced Computations Department at Stanford Linear Accelerator Center is looking into simulations of complex, multi-cavity geometries with lower- and higher-order modes waveguide dampers using ACE3P. This contribution provides the current R&D status of the SPX project.

  9. Hanford Site groundwater monitoring: Setting, sources and methods

    Energy Technology Data Exchange (ETDEWEB)

    M.J. Hartman

    2000-04-11

    Groundwater monitoring is conducted on the Hanford Site to meet the requirements of the Resource Conservation and Recovery Act of 1976 (RCRA); Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA); U.S. Department of Energy (DOE) orders; and the Washington Administrative Code. Results of monitoring are published annually (e.g., PNNL-11989). To reduce the redundancy of these annual reports, background information that does not change significantly from year to year has been extracted from the annual report and published in this companion volume. This report includes a description of groundwater monitoring requirements, site hydrogeology, and waste sites that have affected groundwater quality or that require groundwater monitoring. Monitoring networks and methods for sampling, analysis, and interpretation are summarized. Vadose zone monitoring methods and statistical methods also are described. Whenever necessary, updates to information contained in this document will be published in future groundwater annual reports.

  10. DEVELOPMENT OF A COMPACT PHOTO-INJECTOR WITH RFFOCUSING LENS FOR SHORT PULSE ELECTRON SOURCE APPLICATION

    Energy Technology Data Exchange (ETDEWEB)

    Grabenhofer, Alexander [Northern Illinois University; Eaton, Douglas W. [ScandiNova systems AB, Uppsala, Sweden

    2013-09-01

    For development of compact ultrafast electron source system, we are currently designing a short-pulse RF-gun with RF focusing structure by means of a series of comprehensive modeling analysis processes. EM design of a 2.5 cell resonant cavity with input coupler, acceleration dynamics of photo-emitted electron bunch, EM design of RF-lens with input coupler, and phasespace analysis of focused electron bunch are systematically examined with multi-physics simulators. All the features of the 2.856 GHz cavity geometry were precisely engineered for acceleration energies ranging from 100 keV to 500 keV (safety limited) to be powered by our 5 MW S-band klystron. The klystron (Thales TH2163) and modulator system (ScandiNova K1 turnkey system) were successfully installed and tested. Performance tests of the klystron system show peak output power > 5 MW, as per operation specifications. At the quasi-relativistic energies, the electron source is capable of generating 100fC – 1 pC electron bunch with pulse duration close to 30 fs – 1 ps and transverse size of a few hundred microns. PIC simulations have shown that the electron bunch undergoes fast RF acceleration, rapidly reaching the desired energies, which can be controlled by tuning RF injection phase and input driving power. It has been shown that it is possible to also focus/compress the bunch longitudinally using a RF-lens, which would allow us to control the temporal resolution of the system as well. While our primary analysis has been performed on a 2.5 cell design, we are also looking into half-cell (single cavity) design that is expected to provide the same range of beam energy with a simple configuration.

  11. Soil Monitor: an open source web application for real-time soil sealing monitoring and assessment

    Science.gov (United States)

    Langella, Giuliano; Basile, Angelo; Giannecchini, Simone; Iamarino, Michela; Munafò, Michele; Terribile, Fabio

    2016-04-01

    Soil sealing is one of the most important causes of land degradation and desertification. In Europe, soil covered by impermeable materials has increased by about 80% from the Second World War till nowadays, while population has only grown by one third. There is an increasing concern at the high political levels about the need to attenuate imperviousness itself and its effects on soil functions. European Commission promulgated a roadmap (COM(2011) 571) by which the net land take would be zero by 2050. Furthermore, European Commission also published a report in 2011 providing best practices and guidelines for limiting soil sealing and imperviousness. In this scenario, we developed an open source and an open source based Soil Sealing Geospatial Cyber Infrastructure (SS-GCI) named as "Soil Monitor". This tool merges a webGIS with parallel geospatial computation in a fast and dynamic fashion in order to provide real-time assessments of soil sealing at high spatial resolution (20 meters and below) over the whole Italy. Common open source webGIS packages are used to implement both the data management and visualization infrastructures, such as GeoServer and MapStore. The high-speed geospatial computation is ensured by a GPU parallelism using the CUDA (Computing Unified Device Architecture) framework by NVIDIA®. This kind of parallelism required the writing - from scratch - all codes needed to fulfil the geospatial computation built behind the soil sealing toolbox. The combination of GPU computing with webGIS infrastructures is relatively novel and required particular attention at the Java-CUDA programming interface. As a result, Soil Monitor is smart because it can perform very high time-consuming calculations (querying for instance an Italian administrative region as area of interest) in less than one minute. The web application is embedded in a web browser and nothing must be installed before using it. Potentially everybody can use it, but the main targets are the

  12. The role of executive function in children’s source monitoring with varying retrieval strategies

    Directory of Open Access Journals (Sweden)

    Becky eEarhart

    2014-05-01

    Full Text Available Previous research on the relationship between executive function and source monitoring in young children has been inconclusive, with studies finding conflicting results about whether working memory and inhibitory control are related to source-monitoring ability. In this study, the role of working memory and inhibitory control in recognition memory after exposure to multiple sources, and in source monitoring with two different retrieval strategies were examined. Children (N = 263 aged 4 to 8 participated in science activities with two sources. They were later given a recognition and source-monitoring test, and completed measures of working memory and inhibitory control. During the source-monitoring test, half of the participants were asked about sources serially (one after the other whereas the other half of the children were asked about sources in parallel (considering both sources simultaneously. Results demonstrated that working memory was a predictor of source-monitoring accuracy in both conditions, but inhibitory control was only related to source accuracy in the parallel condition. When age was controlled, these relationships were no longer significant, suggesting that a more general cognitive development factor is a stronger predictor of source monitoring than executive function alone. Interestingly, the children aged 4 to 6 years made more accurate source decisions in the parallel condition compared to those in the serial condition. The older children (aged 7 to 8 were more accurate than the younger children, and their accuracy did not differ as a function of interview condition. Suggestions are provided to guide further research in this area that will clarify the diverse results of previous studies showing executive function is a cognitive prerequisite for effective source monitoring.

  13. A micropower supervisor for wireless nodes with a digital pulse frequency modulator battery monitor

    Science.gov (United States)

    Carloni, Mirko; d'Aparo, Rocco; Scorrano, Pierpaolo; Naticchia, Berardo; Conti, Massimo

    2013-05-01

    In the last few years the increased development of wireless technologies led to the development of micropower devices with power management and real time power control, aimed to maximize the battery life time.1 The main and simplest method to estimate residual battery life time is by voltage measurement. This kind of measurement is simple but is useless in many cases, especially when long term Lithium-Thionyl chloride batteries are used, since its voltage is flat for more than 90% of the battery discharge. In this case, a current control should be used. However, these kinds of devices have various problems as a limited range of measurement and not negligible quiescent current that may distort the measurements. In this work we developed a micropower supervisor for wireless sensor nodes with a charge battery monitor, whose features are aimed at solving the problems just described. The current measured by a sense resistor, is filtered by a super-capacitor, amplified by a current sense amplifier and then fed to a voltage to pulse frequency modulator. In this way, the charge consumption can be estimated without the saturation of the current sense amplifier, even if the wireless node consumes time limited high current spikes, for example during transmission.

  14. The STM32 microcontroller based pulse intensity registration system for the neutron monitor

    Directory of Open Access Journals (Sweden)

    Shepetov Alexander

    2017-01-01

    Full Text Available We present the outlines of a new microcontroller based data acquisition system which is aimed for reliable operation in a typical cosmic ray particle registration experiment. The system supports connection of up to 16 input signals and ensures the following operation functionality: (1 stable monitoring of the intensity of a digital pulse signal, or digitization of a continuous potential level with a low time resolution (typically, about 1 s–100 s; (2 registration of uninterruptable high-resolution (up to 5–10 μs time series of the input signal intensity; (3 synchronization of registered time series with both external (physical or local (program-based trigger signal; (4 possibility of an on-the-fly change of the whole configuration of informational system (both the combination and type of input signals, time resolution and sum duration of the time series measurements, trigger logic, etc. immediately in operation time through convenient communication by plain text messages in dialog mode. In particular, the considered system is applied now for a long-term, high precision measurement of the counting rate of neutron signals at the NM64 type neutron supermonitor of the Tien Shan mountain cosmic ray station, with a real-time representation of the whole collected dataset in a WWW database.

  15. The STM32 microcontroller based pulse intensity registration system for the neutron monitor

    Science.gov (United States)

    Shepetov, Alexander; Chubenko, Alexander; Kryakunova, Olga; Nikolayevsky, Nikolay; Salikhov, Nazyf; Yanke, Victor

    2017-06-01

    We present the outlines of a new microcontroller based data acquisition system which is aimed for reliable operation in a typical cosmic ray particle registration experiment. The system supports connection of up to 16 input signals and ensures the following operation functionality: (1) stable monitoring of the intensity of a digital pulse signal, or digitization of a continuous potential level with a low time resolution (typically, about 1 s-100 s); (2) registration of uninterruptable high-resolution (up to 5-10 μs) time series of the input signal intensity; (3) synchronization of registered time series with both external (physical) or local (program-based) trigger signal; (4) possibility of an on-the-fly change of the whole configuration of informational system (both the combination and type of input signals, time resolution and sum duration of the time series measurements, trigger logic, etc.) immediately in operation time through convenient communication by plain text messages in dialog mode. In particular, the considered system is applied now for a long-term, high precision measurement of the counting rate of neutron signals at the NM64 type neutron supermonitor of the Tien Shan mountain cosmic ray station, with a real-time representation of the whole collected dataset in a WWW database.

  16. Factors that affect pulse wave time transmission in the monitoring of cardiovascular system.

    Science.gov (United States)

    Foo, Jong Yong A; Wilson, Stephen J; Wang, Ping

    2008-04-01

    Vascular transit time (VTT) can be defined as the first heart sound of the phonocardiography (PCG) signal to its arrival at the photoplethysmography (PPG). Studies have shown that monitoring VTT can be useful as an early prognosis of cardiac diseases. However, there is limited study conducted to understand the physiologic factors that affect VTT at the upper limb. In this study, the effect associated with difference in subject height, weight, heart rate, mean arterial pressure, systolic and diastolic blood pressure was assessed. A study population of 31 healthy Chinese young adults (21 male; age range 20-33 yr) were recruited. PCG and PPG were recorded non-invasively from the fourth costal cartilage at the midclavicular line and right index finger, respectively. A single sample Kolmogorov-Smirnov (K-S) goodness-of-fit hypothesis test, a univariate linear regression analysis, and a multiple linear regression modelling were performed on the VTT measurements and the associated physiologic parameters. The results from the K-S test showed that the physiologic parameters and VTT measurements had a normal cumulative distribution function. Furthermore, all physiologic parameters were significantly and independently related to VTT (P VTT regression model was also derived (r (2) = 0.79). The findings herein suggest that the observed physiologic parameters have significant contributions to the nominal VTT value of a subject. Unlike pulse transit time, the VTT technique has the added advantage that the left ventricular isometric contraction time is not included in the timing derivation.

  17. A new fibre optic pulse oximeter probe for monitoring splanchnic organ arterial blood oxygen saturation.

    Science.gov (United States)

    Hickey, M; Samuels, N; Randive, N; Langford, R; Kyriacou, P A

    2012-12-01

    A new, continuous method of monitoring splanchnic organ oxygen saturation (SpO(2)) would make the early detection of inadequate tissue oxygenation feasible, reducing the risk of hypoperfusion, severe ischaemia, and, ultimately, death. In an attempt to provide such a device, a new fibre optic based reflectance pulse oximeter probe and processing system were developed followed by an in vivo evaluation of the technology on seventeen patients undergoing elective laparotomy. Photoplethysmographic (PPG) signals of good quality and high signal-to-noise ratio were obtained from the small bowel, large bowel, liver and stomach. Simultaneous peripheral PPG signals from the finger were also obtained for comparison purposes. Analysis of the amplitudes of all acquired PPG signals indicated much larger amplitudes for those signals obtained from splanchnic organs than those obtained from the finger. Estimated SpO(2) values for splanchnic organs showed good agreement with those obtained from the finger fibre optic probe and those obtained from a commercial device. These preliminary results suggest that a miniaturized 'indwelling' fibre optic sensor may be a suitable method for pre-operative and post-operative evaluation of splanchnic organ SpO(2) and their health.

  18. The role of executive function in children's source monitoring with varying retrieval strategies

    Science.gov (United States)

    Earhart, Becky; Roberts, Kim P.

    2014-01-01

    Previous research on the relationship between executive function and source monitoring in young children has been inconclusive, with studies finding conflicting results about whether working memory and inhibitory control are related to source-monitoring ability. In this study, the role of working memory and inhibitory control in recognition memory and source monitoring with two different retrieval strategies were examined. Children (N = 263) aged 4–8 participated in science activities with two sources. They were later given a recognition and source-monitoring test, and completed measures of working memory and inhibitory control. During the source-monitoring test, half of the participants were asked about sources serially (one after the other) whereas the other half of the children were asked about sources in parallel (considering both sources simultaneously). Results demonstrated that working memory was a predictor of source-monitoring accuracy in both conditions, but inhibitory control was only related to source accuracy in the parallel condition. When age was controlled these relationships were no longer significant, suggesting that a more general cognitive development factor is a stronger predictor of source monitoring than executive function alone. Interestingly, the children aged 4–6 years made more accurate source decisions in the parallel condition than in the serial condition. The older children (aged 7–8) were overall more accurate than the younger children, and their accuracy did not differ as a function of interview condition. Suggestions are provided to guide further research in this area that will clarify the diverse results of previous studies examining whether executive function is a cognitive prerequisite for effective source monitoring. PMID:24847302

  19. USE OF OPEN SOURCE TECHNOLOGIES FOR ENTERPRISE SERVER MONITORING USING SNMP

    Directory of Open Access Journals (Sweden)

    ANSHUL KAUSHIK

    2010-10-01

    Full Text Available This paper focuses on the evolving trend of Data Center Monitoring inenterprise using SNMP protocol & open source platforms for proactive server monitoring and data center management. It also focuses on the need of data center monitoring and escalations for pro active approach.

  20. Design of a laboratory for experiments with a pulsed neutron source.

    Science.gov (United States)

    Memoli, G; Trusler, J P M; Ziver, A K

    2009-06-01

    We present the results of a neutron shielding design and optimisation study performed to reduce the exposure to radiological doses arising from a 14 MeV pulsed neutron generator (PNG) having a maximum emission strength of 2.0 x 10(8) neutrons s(-1). The source was intended to be used in a new irradiation facility for the realisation of an experiment on acoustical cavitation in liquids. This paper describes in detail how the facility was designed to reduce both neutron and gamma-ray dose rates to acceptable levels, taking into account the ALARP principle in following the steps of optimisation. In particular, this work compares two different methods of optimisation to assess neutron dose rates: the use of analytical methods and the use of Monte Carlo simulations (MCNPX 2.4). The activation of the surrounding materials during operation was estimated using the neutron spectra as input to the FISPACT 3.0 code. The limitations of a first-order analytical model to determine the neutron activation levels are highlighted. The impact that activation has on the choice of the materials to be used inside the laboratory and on the waiting time before anyone can safely enter the room after the neutron source is switched off is also discussed.

  1. Operating modes of a hydrogen ion source based on a hollow-cathode pulsed Penning discharge

    Energy Technology Data Exchange (ETDEWEB)

    Oks, E. M. [Institute of High Current Electronics, Siberian Branch of Russian Academy of Science, Tomsk (Russian Federation); Tomsk State University of Control System and Radioelectronics, Tomsk (Russian Federation); Shandrikov, M. V., E-mail: shandrikov@opee.hcei.tsc.ru; Vizir, A. V. [Institute of High Current Electronics, Siberian Branch of Russian Academy of Science, Tomsk (Russian Federation)

    2016-02-15

    An ion source based on a hollow-cathode Penning discharge was switched to a high-current pulsed mode (tens of amperes and tens of microseconds) to produce an intense hydrogen ion beam. With molecular hydrogen (H{sub 2}), the ion beam contained three species: H{sup +}, H{sub 2}{sup +}, and H{sub 3}{sup +}. For all experimental conditions, the fraction of H{sub 2}{sup +} ions in the beam was about 10 ÷ 15% of the total ion beam current and varied little with ion source parameters. At the same time, the ratio of H{sup +} and H{sub 3}{sup +} depended strongly on the discharge current, particularly on its distribution in the gap between the hollow and planar cathodes. Increasing the discharge current increased the H{sup +} fraction in ion beam. The maximum fraction of H{sup +} reached 80% of the total ion beam current. Forced redistribution of the discharge current in the cathode gap for increasing the hollow cathode current could greatly increase the H{sub 3}{sup +} fraction in the beam. At optimum parameters, the fraction of H{sub 3}{sup +} ions reached 60% of the total ion beam current.

  2. Intense Pulsed Neutron Source: Progress report 1991--1996. 15. Anniversary edition -- Volume 2

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-05-01

    The 15th Anniversary Edition of the IPNS Progress Report is being published in recognition of the Intense Pulsed Neutron Source`s first 15 years of successful operation as a user facility. To emphasize the importance of this milestone, the author shave made the design and organization of the report significantly different from previous IPNS Progress Reports. This report consists of two volumes. For Volume 1, authors were asked to prepare articles that highlighted recent scientific accomplishments at IPNS, from 1991 to present; to focus on and illustrate the scientific advances achieved through the unique capabilities of neutron studies performed by IPNS users; to report on specific activities or results from an instrument; or to focus on a body of work encompassing different neutron-scattering techniques. Articles were also included on the accelerator system, instrumentation, computing, target, and moderators. A list of published and ``in press` articles in journals, books, and conference proceedings, resulting from work done at IPNS since 1991, was compiled. This list is arranged alphabetically according to first author. Publication references in the articles are listed by last name of first author and year of publication. The IPNS experimental reports received since 1991 are compiled in Volume 2. Experimental reports referenced in the articles are listed by last name of first author, instrument designation, and experiment number.

  3. Intense Pulsed Neutron Source: Progress report 1991--1996. 15. Anniversary edition -- Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    Marzec, B. [ed.

    1996-05-01

    The 15th Anniversary Edition of the IPNS Progress Report is being published in recognition of the Intense Pulsed Neutron Source`s first 15 years of successful operation as a user facility. To emphasize the importance of this milestone, the authors have made the design and organization of the report significantly different from previous IPNS Progress Reports. This report consists of two volumes. For Volume 1, authors were asked to prepare articles that highlighted recent scientific accomplishments at IPNS, from 1991 to present; to focus on and illustrate the scientific advances achieved through the unique capabilities of neutron studies performed by IPNS users; to report on specific activities or results from an instrument; or to focus on a body of work encompassing different neutron-scattering techniques. Articles were also included on the accelerator system, instrumentation, computing, target, and moderators. A list of published and ``in press` articles in journals, books, and conference proceedings, resulting from work done at IPNS since 1991, was compiled. This list is arranged alphabetically according to first author. Publication references in the articles are listed by last name of first author and year of publication. The IPNS experimental reports received since 1991 are compiled in Volume 2. Experimental reports referenced in the articles are listed by last name of first author, instrument designation, and experiment number.

  4. Ground Source Heat Pump in Heating System with Electronics Monitoring

    Directory of Open Access Journals (Sweden)

    NEAMŢU Ovidiu

    2013-10-01

    Full Text Available The monitoring system is implemented for a ground coupled heat pump in heating/ system. The borehole heat exchangers – which are 150 m long - are filled with a mixture of water and ethilene glycol calledbrine. Metering and monitoring energy consumption is achieved for: heat pump, circulation pumps, additional electrical heating, hot air ventilation systems, control systems with sensors: analog and smart sensors. Instantaneous values are stored in a local computer.

  5. Using Adaptive Discrete-Time Gas Supply Control for Long Pulse Arc Discharge of Ion Source on NBI

    Institute of Scientific and Technical Information of China (English)

    SHENG Peng; HU Chundong; SONG Shihua; LIU Sheng; LIU Zhimin

    2008-01-01

    A control model of gas supply system is introduced for ion source and an adaptive discrete-time control algorithm to regulate the hydrogen injection.A real-time feedback control system (RFCS) is designed to control the gas supply for ion source based on the control model and the discrete-time control algorithm.The experimental results have proved that RFCS could regulate the gas supply smoothly,suppress the arc's abrupt over-current at the end of the ion source discharging,prolong the discharge pulse and stabilize the ion concentration.With RFCS,the ion source for neutral beam injection has reached its longest pulse with a length of 4.5 seconds in a stable status.

  6. Electron energy distributions and electron impact source functions in Ar/N{sub 2} inductively coupled plasmas using pulsed power

    Energy Technology Data Exchange (ETDEWEB)

    Logue, Michael D., E-mail: mdlogue@umich.edu; Kushner, Mark J., E-mail: mjkush@umich.edu [Department of Electrical Engineering and Computer Science, University of Michigan, 1301 Beal Ave., Ann Arbor, Michigan 48109-2122 (United States)

    2015-01-28

    In plasma materials processing, such as plasma etching, control of the time-averaged electron energy distributions (EEDs) in the plasma allows for control of the time-averaged electron impact source functions of reactive species in the plasma and their fluxes to surfaces. One potential method for refining the control of EEDs is through the use of pulsed power. Inductively coupled plasmas (ICPs) are attractive for using pulsed power in this manner because the EEDs are dominantly controlled by the ICP power as opposed to the bias power applied to the substrate. In this paper, we discuss results from a computational investigation of EEDs and electron impact source functions in low pressure (5–50 mTorr) ICPs sustained in Ar/N{sub 2} for various duty cycles. We find there is an ability to control EEDs, and thus source functions, by pulsing the ICP power, with the greatest variability of the EEDs located within the skin depth of the electromagnetic field. The transit time of hot electrons produced in the skin depth at the onset of pulse power produces a delay in the response of the EEDs as a function of distance from the coils. The choice of ICP pressure has a large impact on the dynamics of the EEDs, whereas duty cycle has a small influence on time-averaged EEDs and source functions.

  7. Measurement of ultracold neutrons produced by using Doppler-shifted Bragg reflection at a pulsed-neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Brun, T.O.; Carpenter, J.M.; Krohn, V.E.; Ringo, G.R.; Cronin, J.W.; Dombeck, T.W.; Lynn, J.W.; Werner, S.A.

    1979-01-01

    Ultracold neutrons (UCN) have been produced at the Argonne pulsed-neutron source by the Doppler shift of 400-m/s neutrons Bragg reflected from a moving crystal. The peak density of UCN produced at the crystal exceeds 0.1 n/cm/sup 3/.

  8. Optical Cherenkov radiation by cascaded nonlinear interaction: an efficient source of few-cycle near- to mid-IR pulses

    DEFF Research Database (Denmark)

    Bache, Morten; Bang, Ole; Zhou, Binbin

    2011-01-01

    Through cascaded second-harmonic generation, few-cycle solitons can form that resonantly emit strongly red-shifted optical Cherenkov radiation. Numerical simulations show that such dispersive waves can be an efficient source of near- to mid-IR few-cycle broadband pulses....

  9. Genetic diversity demonstrated by pulsed field gel electrophoresis of Salmonella enterica isolates obtained from diverse sources in Mexico

    Science.gov (United States)

    This study was conducted to determine the genetic diversity of Salmonella isolates recovered from a variety of sources using pulsed-field gel electrophoresis (PFGE) to assess their possible relatedness. Salmonella was isolated from ca. 52% of samples from a pepper var. Bell production system. A to...

  10. A global catalogue of large SO2 sources and emissions derived from the Ozone Monitoring Instrument

    OpenAIRE

    Fioletov, Vitali E.; McLinden, Chris A; Krotkov, Nickolay; Li, Can; Joiner, Joanna; Theys, Nicolas; Carn, Simon; Moran, Mike D.

    2016-01-01

    Sulfur dioxide (SO2) measurements from the Ozone Monitoring Instrument (OMI) satellite sensor processed with the new principal component analysis (PCA) algorithm were used to detect large point emission sources or clusters of sources. The total of 491 continuously emitting point sources releasing from about 30 kt yr−1 to more than 4000 kt yr−1 of SO2 per year have been identified and grouped by country and by primary source origin: volcanoes (76 sources); power plants (297);...

  11. A global catalogue of large SO2 sources and emissions derived from the Ozone Monitoring Instrument

    OpenAIRE

    Fioletov, Vitali E.; McLinden, Chris A; Krotkov, Nickolay; Li, Can; Joiner, Joanna; Theys, Nicolas; Carn, Simon; Moran, Mike D.

    2016-01-01

    Sulphur dioxide (SO2) measurements from the Ozone Monitoring Instrument (OMI) satellite sensor processed with the new Principal Component Analysis (PCA) algorithm were used to detect large point emission sources or clusters of sources. The total of 491 continuously emitting point sources releasing from about 30 kt yr−1 to more than 4000 kt yr−1 of SO2 per year have been identified and grouped by country and by primary source origin: volcanoes (76 sources); power plants (297); smel...

  12. Towards ‘smart lasers’: self-optimisation of an ultrafast pulse source using a genetic algorithm

    Science.gov (United States)

    Woodward, R. I.; Kelleher, E. J. R.

    2016-11-01

    Short-pulse fibre lasers are a complex dynamical system possessing a broad space of operating states that can be accessed through control of cavity parameters. Determination of target regimes is a multi-parameter global optimisation problem. Here, we report the implementation of a genetic algorithm to intelligently locate optimum parameters for stable single-pulse mode- locking in a Figure-8 fibre laser, and fully automate the system turn-on procedure. Stable ultrashort pulses are repeatably achieved by employing a compound fitness function that monitors both temporal and spectral output properties of the laser. Our method of encoding photonics expertise into an algorithm and applying machine-learning principles paves the way to self-optimising ‘smart’ optical technologies.

  13. Source Identification Of Airborne Antimony On The Basis Of The Field Monitoring And The Source Profiling

    Science.gov (United States)

    Iijima, A.; Sato, K.; Fujitani, Y.; Fujimori, E.; Tanabe, K.; Ohara, T.; Shimoda, M.; Kozawa, K.; Furuta, N.

    2008-12-01

    The results of the long-term monitoring of airborne particulate matter (APM) in Tokyo indicated that APM have been extremely enriched with antimony (Sb) compared to crustal composition. This observation suggests that the airborne Sb is distinctly derived from human activities. According to the material flow analysis, automotive brake abrasion dust and fly ash from waste incinerator were suspected as the significant Sb sources. To clarify the emission sources of the airborne Sb, elemental composition, particle size distribution, and morphological profiles of dust particles collected from two possible emission sources were characterized and compared to the field observation data. Brake abrasion dust samples were generated by using a brake dynamometer. During the abrasion test, particle size distribution was measured by an aerodynamic particle sizer spectrometer. Concurrently, size- classified dust particles were collected by an Andersen type air sampler. Fly ash samples were collected from several municipal waste incinerators, and the bulk ash samples were re-dispersed into an enclosed chamber. The measurement of particle size distribution and the collection of size-classified ash particles were conducted by the same methodologies as described previously. Field observations of APM were performed at a roadside site and a residential site by using an Andersen type air sampler. Chemical analyses of metallic elements were performed by an inductively coupled plasma atomic emission spectrometry and an inductively coupled plasma mass spectrometr. Morphological profiling of the individual particle was conducted by a scanning electron microscope equipped with an energy dispersive X-ray spectrometer. High concentration of Sb was detected from both of two possible sources. Particularly, Sb concentrations in a brake abrasion dust were extremely high compared to that in an ambient APM, suggesting that airborne Sb observed at the roadside might have been largely derived from

  14. Dynamic Radioactive Source for Evaluating and Demonstrating Time-dependent Performance of Continuous Air Monitors.

    Science.gov (United States)

    McLean, Thomas D; Moore, Murray E; Justus, Alan L; Hudston, Jonathan A; Barbé, Benoît

    2016-11-01

    Evaluation of continuous air monitors in the presence of a plutonium aerosol is time intensive, expensive, and requires a specialized facility. The Radiation Protection Services Group at Los Alamos National Laboratory has designed a Dynamic Radioactive Source, intended to replace plutonium aerosol challenge testing. The Dynamic Radioactive Source is small enough to be inserted into the sampler filter chamber of a typical continuous air monitor. Time-dependent radioactivity is introduced from electroplated sources for real-time testing of a continuous air monitor where a mechanical wristwatch motor rotates a mask above an alpha-emitting electroplated disk source. The mask is attached to the watch's minute hand, and as it rotates, more of the underlying source is revealed. The measured alpha activity increases with time, simulating the arrival of airborne radioactive particulates at the air sampler inlet. The Dynamic Radioactive Source allows the temporal behavior of puff and chronic release conditions to be mimicked without the need for radioactive aerosols. The new system is configurable to different continuous air monitor designs and provides an in-house testing capability (benchtop compatible). It is a repeatable and reusable system and does not contaminate the tested air monitor. Test benefits include direct user control, realistic (plutonium) aerosol spectra, and iterative development of continuous air monitor alarm algorithms. Data obtained using the Dynamic Radioactive Source has been used to elucidate alarm algorithms and to compare the response time of two commercial continuous air monitors.

  15. A radio monitoring survey of ultra-luminous X-ray sources

    NARCIS (Netherlands)

    Körding, E.; Colbert, E.; Falcke, H.D.E.

    2005-01-01

    We present the results of a radio monitoring campaign to search for radio emission from nearby ultra-luminous X-ray sources (ULXs). These sources are bright off-nuclear X-ray point sources with luminosities exceeding LX > 1039 erg s-1. A well-defined sample of the 9

  16. Comments on the possibility of cavitation in liquid metal targets for pulsed spallation neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    Carpenter J.M. [Argonne National Lab., IL (United States)

    1996-06-01

    When short pulses of protons strike the volume of a liquid target, the rapid heating produces a pressurized region which relaxes as the pressure wave propagates outward. Skala and Bauer have modeled the effects of the pressure wave impinging on the container walls of a liquid mercury target under ESS conditions. They find that high pressures and high wall stresses result if the medium is uniform, nearly incompressible liquid. The pressure and the stresses are much reduced if the liquid contains bubbles of helium, due to their high compressibility. However, according to the calculation, the pressure still reaches an atmosphere or so at the surface, which reflects the compressive wave as a rarefaction wave of the same magnitude. Even such modest underpressures can lead to the growth of bubbles (cavitation) at or near the surface, which can collapse violently and erode the container surface. It is necessary to avoid this. Leighton provides a wide ranging discussion of pressure waves in bubbly media, which may provide insights into the nature and control of cavitation phenomena. The paper surveys some of the relevant information from that source.

  17. Cryogenic capability for equation-of-state measurements on the Sandia Z pulsed radiation source

    Energy Technology Data Exchange (ETDEWEB)

    Hanson, D.L.; Johnston, R.R.; Asay, J.R.

    1998-02-01

    Experimental cryogenic capabilities are essential for the study of ICF high-gain target and weapons effects issues involving dynamic materials response at low temperatures. The authors are developing a general purpose cryogenic target system for precision radiation driven EOS and shock physics experiments at liquid helium temperatures on the Sandia Z pulsed radiation source. Cryogenic sample cooling in the range of 6--30 K is provided by a liquid helium cryostat and an active temperature control system. The cryogenic target assembly is capable of condensing liquid deuterium samples from the gas phase at about 20 K, as well as cooling solid samples such as beryllium and CH ablators for ICF. The target assembly will also include the capability to use various shock diagnostics, such as VISAR interferometry and fiber-optic-coupled shock breakout diagnostics. They are characterizing the thermal and optical performance of the system components in an off-line cryogenic test facility and have designed an interface to introduce the cryogenic transfer lines, gas lines, and sensor cables into the Z vacuum section. Survivability of high-value cryogenic components in the destructive post-implosion environment of Z is a major issue driving the design of this cryogenic target system.

  18. High Field Pulsed Magnets for Neutron Scattering at the Spallation Neutron Source

    Science.gov (United States)

    Granroth, G. E.; Lee, J.; Fogh, E.; Christensen, N. B.; Toft-Petersen, R.; Nojiri, H.

    2015-03-01

    A High Field Pulsed Magnet (HFPM) setup, is in use at the Spallation Nuetron Source(SNS), Oak Ridge National Laboratory. With this device, we recently measured the high field magnetic spin structure of LiNiPO4. The results of this study will be highlighted as an example of possible measurements that can be performed with this device. To further extend the HFPM capabilities at SNS, we have learned to design and wind these coils in house. This contribution will summarize the magnet coil design optimization procedure. Specifically by varying the geometry of the multi-layer coil, we arrive at a design that balances the maximum field strength, neutron scattering angle, and the field homogeneity for a specific set of parameters. We will show that a 6.3kJ capacitor bank, can provide a magnetic field as high as 30T for a maximum scattering angle around 40° with homogeneity of +/- 4 % in a 2mm diameter spherical volume. We will also compare the calculations to measurements from a recently wound test coil. This work was supported in part by the Lab Directors' Research and Development Fund of ORNL.

  19. The upgrade of intense pulsed neutron source (IPNS) through the change of coolant and reflector

    CERN Document Server

    Baek, I C; Iverson, E B

    2002-01-01

    The current intense pulsed neutron source (IPNS) depleted uranium target is cooled by light water. The inner reflector material is graphite and the outer reflector material is beryllium. The presence of H sub 2 O in the target moderates neutrons and leads to a higher absorption loss in the target than is necessary. D sub 2 O coolant in the small quantities required minimizes this effect. We have studied the possible improvement in IPNS beam fluxes that would result from changing the coolant from H sub 2 O to D sub 2 O and the inner reflector from graphite to beryllium. Neutron intensities were calculated for directions normal to the viewed surface of each moderator for four different cases of combinations of target coolant and reflector materials. The simulations reported here were performed using the MCNPX (version 2.1.5) computer program. Our results show that substantial gains in neutron beam intensities can be achieved by appropriate combination of target coolant and reflector materials. The combination o...

  20. STRONG SOLAR WIND DYNAMIC PRESSURE PULSES: INTERPLANETARY SOURCES AND THEIR IMPACTS ON GEOSYNCHRONOUS MAGNETIC FIELDS

    Energy Technology Data Exchange (ETDEWEB)

    Zuo, Pingbing; Feng, Xueshang; Wang, Yi [SIGMA Weather Group, State Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing (China); Xie, Yanqiong [College of Meteorology and Oceanography, PLA University of Science and Technology, Nanjing (China); Xu, Xiaojun, E-mail: pbzuo@spaceweather.ac.cn, E-mail: fengx@spaceweather.ac.cn [Space Science Institute, Macau University of Science and Technology, Macao (China)

    2015-10-20

    In this investigation, we first present a statistical result of the interplanetary sources of very strong solar wind dynamic pressure pulses (DPPs) detected by WIND during solar cycle 23. It is found that the vast majority of strong DPPs reside within solar wind disturbances. Although the variabilities of geosynchronous magnetic fields (GMFs) due to the impact of positive DPPs have been well established, there appears to be no systematic investigations on the response of GMFs to negative DPPs. Here, we study both the decompression effects of very strong negative DPPs and the compression from strong positive DPPs on GMFs at different magnetic local time sectors. In response to the decompression of strong negative DPPs, GMFs on the dayside near dawn and near dusk on the nightside, are generally depressed. But near the midnight region, the responses of GMF are very diverse, being either positive or negative. For part of the events when GOES is located at the midnight sector, the GMF is found to abnormally increase as the result of magnetospheric decompression caused by negative DPPs. It is known that under certain conditions magnetic depression of nightside GMFs can be caused by the impact of positive DPPs. Here, we find that a stronger pressure enhancement may have a higher probability of producing the exceptional depression of GMF at the midnight region. Statistically, both the decompression effect of strong negative DPPs and the compression effect of strong positive DPPs depend on the magnetic local time, which are stronger at the noon sector.

  1. Performance of a solenoid-driven pulsed molecular-beam source

    OpenAIRE

    Abad, Luis; Bermejo, Dionisio; Herrero, Víctor J.; Santos, J.; Tanarro, Isabel

    1995-01-01

    The characteristics of a commonly used pulsed valve for the production of free jets and molecular beams are analyzed in detail. Special attention is paid to the formation of gas pulses providing a quasisteady flow during a certain time interval within the pulse duration, and to the estimation of a scaling parameter (effective diameter) for the description of the flow field. The adequacy of this effective diameter is checked by performing time-of-flight measurements on molecular beams of Ne, N...

  2. Increasing the magnetic helicity content of a plasma by pulsing a magnetized source.

    Science.gov (United States)

    Woodruff, S; Stallard, B W; McLean, H S; Hooper, E B; Bulmer, R; Cohen, B I; Hill, D N; Holcomb, C T; Moller, J; Wood, R D

    2004-11-12

    By operating a magnetized coaxial gun in a pulsed mode it is possible to produce large voltage pulses of duration approximately 500 mus while reaching a few kV, giving a discrete input of helicity into a spheromak. In the sustained spheromak physics experiment (SSPX), it is observed that pulsing serves to nearly double the stored magnetic energy and double the temperature. We discuss these results by comparison with 3D MHD simulations of the same phenomenon.

  3. Electro-optic sampling of THz pulses at the CTR source at FLASH

    Energy Technology Data Exchange (ETDEWEB)

    Wunderlich, Steffen

    2012-06-15

    Several applications in material science, non-linear optics and solid-state physics require short pulses with a high pulse energy of radiation in the far-infrared and in the terahertz (THz) regime in particular. As described in the following, coherent transition radiation generated by high-relativistic electron bunches at FLASH provides broadband single-cycle pulses of sub-picosecond length. The pulses are characterized using the quantitative and time-resolved technique of electro-optic sampling showing peak field strengths in the order of 1 MV/cm.

  4. Optical sensor based on fluorescent quenching and pulsed blue LED excitation for long-term monitoring of dissolved oxygen in NASA space bioreactors.

    Science.gov (United States)

    Gao, Frank G; Fay, James M; Mathew, Grace; Jeevarajan, Antony S; Anderson, Melody M

    2005-01-01

    There is a need to monitor the concentration of dissolved oxygen (DO) present in the culture medium for NASA's space cell biology experiments, as well as in earth-based cell cultures. Continuous measurement of DO concentration in the cell culture medium in perfused bioreactors requires that the oxygen sensor provide adequate sensitivity and low toxicity to the cells, as well as maintain calibration over several weeks. Although there are a number of sensors for dissolved oxygen on the market and under development elsewhere, very few meet these stringent conditions. An in-house optical oxygen sensor (HOXY) based on dynamic fluorescent quenching of Tris(4,7-diphenyl-1,10-phenanthroline)ruthenium(II) chloride and a pulsed blue LED light source was developed in our laboratory to address these requirements. The sensing element consisted of the fluorescent dye embedded in a silicone matrix and coated onto a glass capillary. Photobleaching was minimized by a pulsed LED light source. The total noise in the sensor output is 2% and the sensor dynamic range is 0 to 200 mm Hg. The resolution of the sensor is 0.1 mm Hg at 50 mm Hg, and 0.25 mm Hg at 130 mm Hg, while the accuracy is 5%. The LED-based oxygen sensor exhibited stable performance and low drift, making it compatible for space-flight bioreactor systems.

  5. Pressure and stress waves in a spallation neutron source mercury target generated by high-power proton pulses

    CERN Document Server

    Futakawa, M; Conrad, H; Stechemesser, H

    2000-01-01

    The international ASTE collaboration has performed a first series of measurements on a spallation neutron source target at the Alternating Gradient Synchrotron (AGS) in Brookhaven. The dynamic response of a liquid mercury target hit by high-power proton pulses of about 40 ns duration has been measured by a laser Doppler technique and compared with finite elements calculations using the ABAQUS code. It is shown that the calculation can describe the experimental results for at least the time interval up to 100 mu s after the pulse injection. Furthermore, it has been observed that piezoelectric pressure transducers cannot be applied in the high gamma-radiation field of a spallation target.

  6. Commissioning Status of the 3 MeV RFQ for the Compact Pulsed Hadron Source (CPHS) at Tsinghua University

    CERN Document Server

    Xing, QZ; Stovall, J; He, Y; Guan, WQ; Du, L; Cheng, C; Cai, JC; Bin, DT; Bai, YJ; Wang, XW; Wang, D; Jiang, C; Du, Q; Billen, JH; Li, J; Xiong, ZF; Xing, QZ; Zheng, SX; Zhang, HY; Yang, SY; Qiang, Q; Guan, XL; Du, TB

    2012-01-01

    The 3 MeV Radio Frequency Quadrupole (RFQ) accelerator for the Compact Pulsed Hadron Source (CPHS) is in its initial stage for the commissioning at Tsinghua University. Braze of the flanges was completed in January, 2012. The RFQ cavity has been delivered to Tsinghua University after the final field tuning. In 2012 the 3-meter-long RFQ is expected to deliver 3 MeV protons to the downstream High Energy Beam Transport (HEBT) with the peak current of 50 mA, pulse length of 0.5 ms and beam duty factor of 2.5%. The initial commissioning is now underway.

  7. Novel design of high voltage pulse source for efficient dielectric barrier discharge generation by using silicon diodes for alternating current

    Science.gov (United States)

    Truong, Hoa Thi; Hayashi, Misaki; Uesugi, Yoshihiko; Tanaka, Yasunori; Ishijima, Tatsuo

    2017-06-01

    This work focuses on design, construction, and optimization of configuration of a novel high voltage pulse power source for large-scale dielectric barrier discharge (DBD) generation. The pulses were generated by using the high-speed switching characteristic of an inexpensive device called silicon diodes for alternating current and the self-terminated characteristic of DBD. The operation started to be powered by a primary DC low voltage power supply flexibly equipped with a commercial DC power supply, or a battery, or DC output of an independent photovoltaic system without transformer employment. This flexible connection to different types of primary power supply could provide a promising solution for the application of DBD, especially in the area without power grid connection. The simple modular structure, non-control requirement, transformer elimination, and a minimum number of levels in voltage conversion could lead to a reduction in size, weight, simple maintenance, low cost of installation, and high scalability of a DBD generator. The performance of this pulse source has been validated by a load of resistor. A good agreement between theoretically estimated and experimentally measured responses has been achieved. The pulse source has also been successfully applied for an efficient DBD plasma generation.

  8. In-process monitoring and adaptive control for gap in micro butt welding with pulsed YAG laser

    Science.gov (United States)

    Kawahito, Yousuke; Kito, Masayuki; Katayama, Seiji

    2007-05-01

    A gap is one of the most important issues to be solved in laser welding of a micro butt joint, because the gap results in welding defects such as underfilling or a non-bonded joint. In-process monitoring and adaptive control has been expected as one of the useful procedures for the stable production of sound laser welds without defects. The objective of this research is to evaluate the availability of in-process monitoring and adaptive control in micro butt welding of pure titanium rods with a pulsed neodymium : yttrium aluminium garnet (Nd : YAG) laser beam of a 150 µm spot diameter. It was revealed that a 45 µm narrow gap was detected by the remarkable jump in a reflected light intensity due to the formation of the molten pool which could bridge the gap. Heat radiation signal levels increased in proportion to the sizes of molten pools or penetration depths for the respective laser powers. As for adaptive control, the laser peak power was controlled on the basis of the reflected light or the heat radiation signals to stably produce a sound deeply penetrated weld reduced underfilling. In the case of a 100 µm gap, the underfilling was greatly reduced by half smaller than those made with a conventional rectangular pulse shape in seam welding as well as spot welding with a pulsed Nd : YAG laser beam. Consequently, the adaptive control of the laser peak power on the basis of in-process monitoring could reduce the harmful effects due to a gap in micro butt laser welding with a pulsed laser beam.

  9. In-process monitoring and adaptive control for gap in micro butt welding with pulsed YAG laser

    Energy Technology Data Exchange (ETDEWEB)

    Kawahito, Yousuke; Kito, Masayuki; Katayama, Seiji [Joining and Welding Research Institute (JWRI), Osaka University, 11-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan)

    2007-05-07

    A gap is one of the most important issues to be solved in laser welding of a micro butt joint, because the gap results in welding defects such as underfilling or a non-bonded joint. In-process monitoring and adaptive control has been expected as one of the useful procedures for the stable production of sound laser welds without defects. The objective of this research is to evaluate the availability of in-process monitoring and adaptive control in micro butt welding of pure titanium rods with a pulsed neodymium : yttrium aluminium garnet (Nd : YAG) laser beam of a 150 {mu}m spot diameter. It was revealed that a 45 {mu}m narrow gap was detected by the remarkable jump in a reflected light intensity due to the formation of the molten pool which could bridge the gap. Heat radiation signal levels increased in proportion to the sizes of molten pools or penetration depths for the respective laser powers. As for adaptive control, the laser peak power was controlled on the basis of the reflected light or the heat radiation signals to stably produce a sound deeply penetrated weld reduced underfilling. In the case of a 100 {mu}m gap, the underfilling was greatly reduced by half smaller than those made with a conventional rectangular pulse shape in seam welding as well as spot welding with a pulsed Nd : YAG laser beam. Consequently, the adaptive control of the laser peak power on the basis of in-process monitoring could reduce the harmful effects due to a gap in micro butt laser welding with a pulsed laser beam.

  10. Developments of fast emittance monitors for ion sources at RCNP

    Science.gov (United States)

    Yorita, T.; Hatanaka, K.; Fukuda, M.; Shimada, K.; Yasuda, Y.; Saito, T.; Tamura, H.; Kamakura, K.

    2016-02-01

    Recently, several developments of low energy beam transport line and its beam diagnostic systems have been performed to improve the injection efficiency of ion beam to azimuthally varying field cyclotron at Research Center for Nuclear Physics, Osaka University. One of those is the fast emittance monitor which can measure within several seconds for the efficient beam development and a Pepper-Pot Emittance Monitor (PPEM) has been developed. The PPEM consists of pepper-pot mask, multichannel plate, fluorescent screen, mirror, and CCD camera. The CCD image is taken via IEEE1394b to a personal computer and analyzed immediately and frequently, and then real time measurement with about 2 Hz has been achieved.

  11. Developments of fast emittance monitors for ion sources at RCNP

    Energy Technology Data Exchange (ETDEWEB)

    Yorita, T., E-mail: yorita@rcnp.osaka-u.ac.jp; Hatanaka, K.; Fukuda, M.; Shimada, K.; Yasuda, Y.; Saito, T.; Tamura, H.; Kamakura, K. [Research Center for Nuclear Physics (RCNP), Osaka University, Osaka 567-0047 (Japan)

    2016-02-15

    Recently, several developments of low energy beam transport line and its beam diagnostic systems have been performed to improve the injection efficiency of ion beam to azimuthally varying field cyclotron at Research Center for Nuclear Physics, Osaka University. One of those is the fast emittance monitor which can measure within several seconds for the efficient beam development and a Pepper-Pot Emittance Monitor (PPEM) has been developed. The PPEM consists of pepper-pot mask, multichannel plate, fluorescent screen, mirror, and CCD camera. The CCD image is taken via IEEE1394b to a personal computer and analyzed immediately and frequently, and then real time measurement with about 2 Hz has been achieved.

  12. Production of an intense source of micro-second proton pulses; Recherche d'une intense source de protons pulsee a la micro-seconde

    Energy Technology Data Exchange (ETDEWEB)

    Belmont, J.L. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1965-02-01

    In order to obtain micro-second proton pulses of 100 mA, we have built a duoplasmatron ion source and beam focusing equipment. The pulses of the ion-source were produced by a load discharge. The source operates as a hydrogen-thyratron. The particular geometry of the duoplasmatron was chosen in order that the ion emission be stable with a 10 A arc and with a gas-flow lower than 10 cm{sup 3}/h T.P.N. Studies of the beam showed preponderance of protons and the presence of heavy ions. The beam density is higher on the optic axis. (author) [French] Pour obtenir des impulsions d'une microseconde de 100 mA de protons, on a ete amene a construire une source 'duoplasmatron' et son optique de focalisation. La pulsation de la source a ete faite par decharge d'une ligne, la source fonctionnant elle-meme comme un thyratron a hydrogene. La geometrie de la source a ete etudiee pour que l'emission d'ions soit stable avec un arc de 10 amperes de crete et un debit de gaz de 10 cm{sup 3}/h T.P.N. Une analyse du faisceau a revele la preponderance des protons et l'existence d'ions lourds. La densite du faisceau est plus grande sur l'axe de l'optique.

  13. Self-Calibration and Laser Energy Monitor Validations for a Double-Pulsed 2-Micron CO2 Integrated Path Differential Absorption Lidar Application

    Science.gov (United States)

    Refaat, Tamer F.; Singh, Upendra N.; Petros, Mulugeta; Remus, Ruben; Yu, Jirong

    2015-01-01

    Double-pulsed 2-micron integrated path differential absorption (IPDA) lidar is well suited for atmospheric CO2 remote sensing. The IPDA lidar technique relies on wavelength differentiation between strong and weak absorbing features of the gas normalized to the transmitted energy. In the double-pulse case, each shot of the transmitter produces two successive laser pulses separated by a short interval. Calibration of the transmitted pulse energies is required for accurate CO2 measurement. Design and calibration of a 2-micron double-pulse laser energy monitor is presented. The design is based on an InGaAs pin quantum detector. A high-speed photo-electromagnetic quantum detector was used for laser-pulse profile verification. Both quantum detectors were calibrated using a reference pyroelectric thermal detector. Calibration included comparing the three detection technologies in the single-pulsed mode, then comparing the quantum detectors in the double-pulsed mode. In addition, a self-calibration feature of the 2-micron IPDA lidar is presented. This feature allows one to monitor the transmitted laser energy, through residual scattering, with a single detection channel. This reduces the CO2 measurement uncertainty. IPDA lidar ground validation for CO2 measurement is presented for both calibrated energy monitor and self-calibration options. The calibrated energy monitor resulted in a lower CO2 measurement bias, while self-calibration resulted in a better CO2 temporal profiling when compared to the in situ sensor.

  14. Sequential Optimal Monitoring Network Design using Iterative Kriging for Identification of Unknown Groundwater Pollution Sources Location

    Science.gov (United States)

    Prakash, O.; Datta, B.

    2011-12-01

    Identification of unknown groundwater pollution source characteristics, in terms of location, magnitude and activity duration is important for designing an effective pollution remediation strategy. Precise source characterization also becomes very important to ascertain liability, and to recover the cost of remediation from parties responsible for the groundwater pollution. Due to the uncertainties in accurately predicting the aquifer response to source flux injection, generally encountered sparsity of concentration observation data in the field, and the non uniqueness in the aquifer response to the subjected hydraulic and chemical stresses, groundwater pollution source characterization remains a challenging task. A scientifically designed pollutant concentration monitoring network becomes imperative for accurate pollutant source characterization. The efficiency of the unknown source locations identification process is largely determined by locations of monitoring wells where the pollutant concentration is observed. The proposed method combines spatial interpolation of concentration measurements and Simulated Annealing as optimization algorithm to find the optimum locations for monitoring wells. Initially, the observed concentration data at few sparsely and arbitrarily distributed wells are used to interpolate the concentration data for the aquifer study area. The concentration information is passed to the optimization algorithm (decision model) as concentration gradient which in turn finds the optimum locations for implementing the next sequence of monitoring wells. Concentration measurement data from these designed monitoring wells and already implemented monitoring network are iteratively used as feedback information for potential groundwater pollution source locations identification. The potential applicability of the developed methodology is demonstrated for an illustrative study area.

  15. Reference source of the radon-222 for modern technology of environmental monitoring in radioactive waste storages

    OpenAIRE

    Солодовнікова, Лідія Миколаївна; Тарасов, Володимир Олексійович

    2013-01-01

    The article describes a reference source of the radon-222 created to solve the problem of probability of environmental monitoring of the radon-222 in storages of radioactive wastes, uranium mines, geodynamic landfills over the study of portents of earthquakes.The main objective of the study is to develop a modern technology of environmental radon monitoring using the built-in reference sources of the radon-222 with the metrological characteristics independent of environmental parameters - tem...

  16. Development of double-pulse lasers ablation system for generating gold ion source under applying an electric field

    Science.gov (United States)

    Khalil, A. A. I.

    2015-12-01

    Double-pulse lasers ablation (DPLA) technique was developed to generate gold (Au) ion source and produce high current under applying an electric potential in an argon ambient gas environment. Two Q-switched Nd:YAG lasers operating at 1064 and 266 nm wavelengths are combined in an unconventional orthogonal (crossed-beam) double-pulse configuration with 45° angle to focus on a gold target along with a spectrometer for spectral analysis of gold plasma. The properties of gold plasma produced under double-pulse lasers excitation were studied. The velocity distribution function (VDF) of the emitted plasma was studied using a dedicated Faraday-cup ion probe (FCIP) under argon gas discharge. The experimental parameters were optimized to attain the best signal to noise (S/N) ratio. The results depicted that the VDF and current signals depend on the discharge applied voltage, laser intensity, laser wavelength and ambient argon gas pressure. A seven-fold increases in the current signal by increasing the discharge applied voltage and ion velocity under applying double-pulse lasers field. The plasma parameters (electron temperature and density) were also studied and their dependence on the delay (times between the excitation laser pulse and the opening of camera shutter) was investigated as well. This study could provide significant reference data for the optimization and design of DPLA systems engaged in laser induced plasma deposition thin films and facing components diagnostics.

  17. 77 FR 8160 - Quality Assurance Requirements for Continuous Opacity Monitoring Systems at Stationary Sources

    Science.gov (United States)

    2012-02-14

    ... AGENCY 40 CFR Part 60 RIN 2060-AH23 Quality Assurance Requirements for Continuous Opacity Monitoring...--Quality Assurance Requirements for Continuous Opacity Monitoring Systems at Stationary Sources Docket, EPA.... Rules establishing quality assurance requirements impose no costs independent from national emission...

  18. 40 CFR 141.88 - Monitoring requirements for lead and copper in source water.

    Science.gov (United States)

    2010-07-01

    ... § 141.88 Monitoring requirements for lead and copper in source water. (a) Sample location, collection... water samples in accordance with the following requirements regarding sample location, number of samples... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Monitoring requirements for lead...

  19. 40 CFR 63.1317 - PET and polystyrene affected sources-monitoring provisions.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 11 2010-07-01 2010-07-01 true PET and polystyrene affected sources-monitoring provisions. 63.1317 Section 63.1317 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... § 63.1317 PET and polystyrene affected sources—monitoring provisions. Continuous process vents using...

  20. Development and testing of a pulsed helium ion source for probing materials and warm dense matter studies

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Q., E-mail: qji@lbl.gov; Seidl, P. A.; Waldron, W. L.; Takakuwa, J. H.; Persaud, A.; Schenkel, T. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Friedman, A.; Grote, D. P.; Barnard, J. J. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

    2016-02-15

    The neutralized drift compression experiment was designed and commissioned as a pulsed, linear induction accelerator to drive thin targets to warm dense matter (WDM) states with peak temperatures of ∼1 eV using intense, short pulses (∼1 ns) of 1.2 MeV lithium ions. At that kinetic energy, heating a thin target foil near the Bragg peak energy using He{sup +} ions leads to more uniform energy deposition of the target material than Li{sup +} ions. Experiments show that a higher current density of helium ions can be delivered from a plasma source compared to Li{sup +} ions from a hot plate type ion source. He{sup +} beam pulses as high as 200 mA at the peak and 4 μs long were measured from a multi-aperture 7-cm-diameter emission area. Within ±5% variation, the uniform beam area is approximately 6 cm across. The accelerated and compressed pulsed ion beams can be used for materials studies and isochoric heating of target materials for high energy density physics experiments and WDM studies.

  1. Time domain measuring system of molecular fluorescence with real-time monitor and control of pulsed dye laser

    Science.gov (United States)

    Taira, Y.; Suzuki, T.; Kato, H.; Konishi, N.; Kasuya, T.

    1982-04-01

    A computer controlled system is presented for a high-precision, time-domain measurement of molecular fluorescence induced by a pulsed dye laser field. In this system three intelligent functions are assembled by the system controller: they are an automatic wavelength control of pulsed dye laser to 0.45 GHz resolution, a digital wavelength meter of 10-7 precision, and a high-speed waveform digitizer with 10 ps inherent resolution. Then the system achieves a unique capability such as to record real-time data of fluorescence decay in the nanosecond regime under an on-line monitor and control of the laser wavelength to milliangstrom precision. The basic constitution and practical performance of the system are described with particular emphasis on its high precision and multi-task capability.

  2. Proceedings of the workshop on ion source issues relevant to a pulsed spallation neutron source: Part 1: Workshop summary

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, L.; Leung, K.N.; Alonso, J. [eds.

    1994-10-01

    The workshop reviewed the ion-source requirements for high-power accelerator-driven spallation neutron facilities, and the performance of existing ion sources. Proposals for new facilities in the 1- to 5-MW range call for a widely differing set of ion-source requirements. For example, the source peak current requirements vary from 40 mA to 150 mA, while the duty factor ranges from 1% to 9%. Much of the workshop discussion centered on the state-of-the-art of negative hydrogen ion source (H{sup {minus}}) technology and the present experience with Penning and volume sources. In addition, other ion source technologies, for positive ions or CW applications were reviewed. Some of these sources have been operational at existing accelerator complexes and some are in the source-development stage on test stands.

  3. Electrical Equivalent Model for an Optical VCO in a PLL Synchronization Scheme for Ultrashort Optical Pulse Sources

    Science.gov (United States)

    Bogoni, Antonella; Potì, Luca; Ponzini, Filippo; Ghelfi, Paolo

    2006-01-01

    The electrical modeling of complex electrooptical devices is a useful task for the correct design of its schemes and for the estimation of its performance. In this paper, we consider an electrooptical phase-locked loop (PLL) used to synchronize an RF system clock to the repetition rate of an optical pulsed source, realized by an active fiber mode-locking (ML) technique in the regenerative configuration. The synchronization scheme is suggested by a description of the pulsed source, for the first time, as an optical voltage-control oscillator (VCO). In particular, we present a simple new all-electrical model for the proposed optical VCO, and we verify its accuracy by the implementation of the whole PLL scheme at 2.5 and 10 GHz.

  4. Optimizing drive parameters of a nanosecond, repetitively pulsed microdischarge high power 121.6 nm source

    Science.gov (United States)

    Stephens, J.; Fierro, A.; Trienekens, D.; Dickens, J.; Neuber, A.

    2015-02-01

    Utilizing nanosecond high voltage pulses to drive microdischarges (MDs) at repetition rates in the vicinity of 1 MHz previously enabled increased time-averaged power deposition, peak vacuum ultraviolet (VUV) power yield, as well as time-averaged VUV power yield. Here, various pulse widths (30-250 ns), and pulse repetition rates (100 kHz-5 MHz) are utilized, and the resulting VUV yield is reported. It was observed that the use of a 50 ns pulse width, at a repetition rate of 100 kHz, provided 62 W peak VUV power and 310 mW time-averaged VUV power, with a time-averaged VUV generation efficiency of ˜1.1%. Optimization of the driving parameters resulted in 1-2 orders of magnitude increase in peak and time-averaged power when compared to low power, dc-driven MDs.

  5. Multiple Time-Scale Monitoring to Address Dynamic Seasonality and Storm Pulses of Stream Water Quality in Mountainous Watersheds

    Directory of Open Access Journals (Sweden)

    Hyun-Ju Lee

    2015-11-01

    Full Text Available Rainfall variability and extreme events can amplify the seasonality and storm pulses of stream water chemistry in mountainous watersheds under monsoon climates. To establish a monitoring program optimized for identifying potential risks to stream water quality arising from rainfall variability and extremes, we examined water chemistry data collected on different timescales. At a small forested watershed, bi-weekly sampling lasted over two years, in comparison to three other biweekly sampling sites. In addition, high-frequency continuous measurements of pH, electrical conductivity, and turbidity were conducted in tandem with automatic water sampling at 2 h intervals during eight rainfall events. Biweekly monitoring showed that during the summer monsoon period, electrical conductivity (EC, dissolved oxygen (DO, and dissolved ion concentrations generally decreased, but total suspended solids (TSS slightly increased. A noticeable variation from the usual seasonal pattern was that DO levels substantially decreased during an extended drought. Bi-hourly storm event samplings exhibited large changes in the concentrations of TSS and particulate and dissolved organic carbon (POC; DOC during intense rainfall events. However, extreme fluctuations in sediment export during discharge peaks could be detected only by turbidity measurements at 5 min intervals. Concomitant measurements during rainfall events established empirical relationships between turbidity and TSS or POC. These results suggest that routine monitoring based on weekly to monthly sampling is valid only in addressing general seasonal patterns or long-lasting phenomena such as drought effects. We propose an “adaptive” monitoring scheme that combines routine monitoring for general seasonal patterns and high-frequency instrumental measurements of water quality components exhibiting rapid responses pulsing during intense rainfall events.

  6. LIGHT SOURCE: Terahertz emission in tenuous gases irradiated by ultrashort laser pulses

    Science.gov (United States)

    Wang, Wei-Min; Sheng, Zheng-Ming; Wit, Hui-Chun; Chen, Min; Li, Chun; Zhang, Jie; Mima, K.

    2009-06-01

    Mechanism of terahertz (THz) pulse generation in gases irradiated by ultrashort laser pulses is investigated theoretically. Quasi-static transverse currents produced by laser field ionization of gases and the longitudinal modulation in formed plasmas are responsible for the THz emission at the electron plasma frequency, as demonstrated by particle-in-cell simulations including field ionization. The THz field amplitude scaling with the laser amplitude within a large range is also discussed.

  7. VizieR Online Data Catalog: mm-monitoring of radio sources IV. (Reuter+ 1997)

    NARCIS (Netherlands)

    Reuter, H.-P.; Kramer, C.; Sievers, A.; Paubert, G.; Moreno, R.; Greve, A.; Leon, S.; Panis, J. F.; Ruiz-Moreno, M.; Ungerechts, H.; Wild, W.

    1997-01-01

    Radio flux densities are presented for 118 extra galactic radio sources monitored at 90, 142 and 230GHz with the IRAM 30m telescope during1993-1994. For the most frequently observed sources we show light curves including 30 m-measurements published in previous papers, Steppe et al.(1988A&AS...75..31

  8. Continuous cuff-less blood pressure monitoring based on the pulse arrival time approach: the impact of posture.

    Science.gov (United States)

    Muehlsteff, J; Aubert, X A; Morren, G

    2008-01-01

    There is an unmet need for cuff-less blood pressure (BP) monitoring especially, in personal healthcare applications. The pulse arrival time (PAT) approach might offer a suitable solution to enable comfortable BP monitoring even at beat-level. However, the methodology is based on hemodynamic surrogate measures, which are sensitive to patient activities such as posture changes, not necessarily related to blood pressure variations. In this paper, we analyze the impact of posture on the PAT measure and related hemodynamic parameters such as the pre-ejection period in well-defined procedures. Additionally, the PAT of a monitored subject is investigated in an unsupervised scenario illustrating the complexity of such a measurement. Our results show the failure of blood pressure inference based on simple calibration strategies using the PAT measure only. We discuss opportunities to compensate for the observed effects towards the realization of wearable cuff-less blood pressure monitoring. These findings emphasize the importance of accessing context information in personal healthcare applications, where vital sign monitoring is typically unsupervised.

  9. Neutron resonance transmission spectroscopy with high spatial and energy resolution at the J-PARC pulsed neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Tremsin, A.S., E-mail: ast@ssl.berkeley.edu [University of California at Berkeley, 7 Gauss Way, Berkeley, CA 94720 (United States); Shinohara, T.; Kai, T.; Ooi, M. [Japan Atomic Energy Agency, 2–4 Shirakata-shirane, Tokai-mura, Naka-gun, Ibaraki 319-1195 (Japan); Kamiyama, T.; Kiyanagi, Y.; Shiota, Y. [Hokkaido University, Kita 13 Nishi 8 Kita-ku, Sapporo-shi, Hokkaido 060-8628 (Japan); McPhate, J.B.; Vallerga, J.V.; Siegmund, O.H.W. [University of California at Berkeley, 7 Gauss Way, Berkeley, CA 94720 (United States); Feller, W.B. [NOVA Scientific, Inc., 10 Picker Rd., Sturbridge, MA 01566 (United States)

    2014-05-11

    The sharp variation of neutron attenuation at certain energies specific to particular nuclides (the lower range being from ∼1 eV up to ∼1 keV), can be exploited for the remote mapping of element and/or isotope distributions, as well as temperature probing, within relatively thick samples. Intense pulsed neutron beam-lines at spallation sources combined with a high spatial, high-timing resolution neutron counting detector, provide a unique opportunity to measure neutron transmission spectra through the time-of-flight technique. We present the results of experiments where spatially resolved neutron resonances were measured, at energies up to 50 keV. These experiments were performed with the intense flux low background NOBORU neutron beamline at the J-PARC neutron source and the high timing resolution (∼20 ns at epithermal neutron energies) and spatial resolution (∼55 µm) neutron counting detector using microchannel plates coupled to a Timepix electronic readout. Simultaneous element-specific imaging was carried out for several materials, at a spatial resolution of ∼150 µm. The high timing resolution of our detector combined with the low background beamline, also enabled characterization of the neutron pulse itself – specifically its pulse width, which varies with neutron energy. The results of our measurements are in good agreement with the predicted results for the double pulse structure of the J-PARC facility, which provides two 100 ns-wide proton pulses separated by 600 ns, broadened by the neutron energy moderation process. Thermal neutron radiography can be conducted simultaneously with resonance transmission spectroscopy, and can reveal the internal structure of the samples. The transmission spectra measured in our experiments demonstrate the feasibility of mapping elemental distributions using this non-destructive technique, for those elements (and in certain cases, specific isotopes), which have resonance energies below a few keV, and with lower

  10. A spectroscopic approach to monitor the cut processing in pulsed laser osteotomy.

    Science.gov (United States)

    Henn, Konrad; Gubaidullin, Gail G; Bongartz, Jens; Wahrburg, Jürgen; Roth, Hubert; Kunkel, Martin

    2013-01-01

    During laser osteotomy surgery, plasma arises at the place of ablation. It was the aim of this study to explore whether a spectroscopic analysis of this plasma would allow identification of the type of tissue that was affected by the laser. In an experimental setup (Rofin SCx10, CO(2) Slab Laser, wavelength 10.6 μm, pulse duration 80 μs, pulse repetition rate 200 Hz, max. output in cw-mode 100 W), the plasma spectra evoked by a pulsed laser, cutting 1-day postmortem pig and cow bones, were recorded. Spectra were compared to the reference spectrum of bone via correlation analysis. Our measurements show a clear differentiation between the plasma spectra when cutting either a bone or a soft tissue. The spectral changes could be detected from one to the next spectrum within 200 ms. Continuous surveillance of plasma spectra allows us to differentiate whether bone or soft tissue is hit by the last laser pulse. With this information, it may be possible to stop the laser when cutting undesired soft tissue and to design an automatic control of the ablation process.

  11. Neutron calibration facility with an Am-Be source for pulse shape discrimination measurement of CsI(Tl) crystals

    CERN Document Server

    Lee, H S; Choi, J H; Choi, S; Hahn, I S; Jeon, E J; Joo, H W; Kang, W G; Kim, G B; Kim, H J; Kim, K W; Kim, S C; Kim, S K; Kim, Y D; Kim, Y H; Lee, J H; Lee, J K; Leonard, D S; Li, J; Myung, S S; Olsen, S L; So, J H

    2014-01-01

    We constructed a neutron calibration facility based on a 300-mCi Am-Be source in conjunction with a search for weakly interacting massive particle candidates for dark matter. The facility is used to study the response of CsI(Tl) crystals to nuclear recoils induced by neutrons from the Am-Be source and comparing them with the response to electron recoils produced by Compton scattering of 662-keV $\\gamma$-rays from a $^{137}$Cs source. The measured results on pulse shape discrimination (PSD) between nuclear- and electron-recoil events are quantified in terms of quality factors. A comparison with similar result from a neutron reactor demonstrate the feasibility of performing calibrations of PSD measurements using neutrons from a Am-Be source.

  12. Reaching white-light radiation source of ultrafast laser pulses with tunable peak power using nonlinear self-phase modulation in neon gas

    Science.gov (United States)

    Tawfik, Walid

    2016-08-01

    A source of white-light radiation that generates few-cycle pulses with controlled peak power values has been developed. These ultrafast pulses have been observed by spectral broadening of 32 fs pulses through nonlinear self-phase modulation in a neon-filled hollow-fiber then compressed with a pair of chirped mirrors for dispersion compensation. The observed pulses reached transform-limited duration of 5.77 fs and their peak power values varied from 57 GW up to 104 GW at repetition rate of 1 kHz. Moreover, the applied method is used for a direct tuning of the peak power of the output pulses through varying the chirping of the input pulses at different neon pressures. The observed results may give an opportunity to control the ultrafast interaction dynamics on the femtosecond time scale and facilitate the regeneration of attosecond pulses.

  13. Optical 40 GHz pulse source module based on a monolithically integrated mode locked DBR laser

    Science.gov (United States)

    Huettl, B.; Kaiser, R.; Kroh, M.; Schubert, C.; Jacumeit, G.; Heidrich, H.

    2005-11-01

    In this paper the performance characteristics of compact optical 40 GHz pulse laser modules consisting of a monolithic mode-locked MQW DBR laser on GaInAsP/InP are reported. The monolithic devices were fabricated as tunable multi-section buried heterostructure lasers. A DBR grating is integrated at the output port of an extended cavity in order to meet the standardized ITU wavelength channels allocated in the spectral window around 1.55 μm in optical high speed communication networks. The fabricated 40 GHz lasers modules not only emit short optical pulses (< 1.5 ps) with very low amplitude noise (<1.5 %) and phase noise levels (timing jitter: 50 fs) but also enable good pulse-to-pulse phase and long-term stability. A wavelength tuning range of 6 nm is possible and large locking bandwidths between 100 ... 260 MHz are observed. All data have been achieved by operating the lasers in a hybrid mode-locking scheme with a required minimum micro-wave power of only 12 dBm for pulse synchronization. Details on laser chip architecture and module performance are summarized and the results of a stable and error free module performance in first 160 Gb/s (4 x 40 Gb/s OTDM) RZ-DPSK transmission experiments are presented.

  14. Developments of compact pulsed-power system toward X-ray sources

    Directory of Open Access Journals (Sweden)

    Miyamoto Takuya

    2013-11-01

    Full Text Available In order to generate X-rays from X-pinch, the peak current and current-rising time required are estimated to be 100 kA and 100 ns, respectively. To obtain these parameters, we developed a pulsed-power system, which consists of a parallelized pulse-forming network (PFN. The 20 PFN modules of the system were driven at a charging voltage of 20 kV by a thin copper wire of load resistance. The results showed that the current and current-rising time are 18 kA and 107 ns, respectively. The wire/plasma temperature is 6.9 eV. The pulsed-power system is expected to generate X-rays from X-pinch by the proposed system. This can be achieved by raising the voltage and increasing the number of PFN modules.

  15. Solar blind chemically vapor deposited diamond detectors for vacuum ultraviolet pulsed light-source characterization

    Science.gov (United States)

    Foulon, F.; Bergonzo, P.; Borel, C.; Marshall, R. D.; Jany, C.; Besombes, L.; Brambilla, A.; Riedel, D.; Museur, L.; Castex, M. C.; Gicquel, A.

    1998-11-01

    A major difficulty in characterizing vacuum ultraviolet (VUV) radiation produced by harmonic generation or four-wave sum frequency mixing arises in differentiating between the desired VUV signal and the remaining fundamental pump laser beam. To overcome this problem, visible and near UV blind VUV detectors, made from natural and synthetic diamond, have been developed. Such detectors have been used to characterize coherent VUV pulses (λ=125 nm, pulse duration at full width half maximum (FWHM) τFWHM~7 ns) generated by resonance-enhanced four-wave sum mixing in mercury vapor. They allow full characterization of the intensity profile of the VUV pulses, without any significant parasitic signal from simultaneous stray light irradiation at λ=313 nm. Detectors were fabricated exhibiting response times of less than 70 ps at FWHM, corresponding to the lowest response time obtainable with a 7 GHz bandwidth single-shot oscilloscope.

  16. A vacuum-sealed, gigawatt-class, repetitively pulsed high-power microwave source

    Science.gov (United States)

    Xun, Tao; Fan, Yu-wei; Yang, Han-wu; Zhang, Zi-cheng; Chen, Dong-qun; Zhang, Jian-de

    2017-06-01

    A compact L-band sealed-tube magnetically insulated transmission line oscillator (MILO) has been developed that does not require bulky external vacuum pump for repetitive operations. This device with a ceramic insulated vacuum interface, a carbon fiber array cathode, and non-evaporable getters has a base vacuum pressure in the low 10-6 Pa range. A dynamic 3-D Monte-Carlo model for the molecular flow movement and collision was setup for the MILO chamber. The pulse desorption, gas evolution, and pressure distribution were exactly simulated. In the 5 Hz repetition rate experiments, using a 600 kV diode voltage and 48 kA beam current, the average radiated microwave power for 25 shots is about 3.4 GW in 45 ns pulse duration. The maximum equilibrium pressure is below 4.0 × 10-2 Pa, and no pulse shortening limitations are observed during the repetitive test in the sealed-tube condition.

  17. Investigation of the Newly Proposed Carrier-Envelope-Phase Stable Attosecond Pulse Source

    CERN Document Server

    Tibai, Z; Nagy-Csiha, Zs; Fülöp, J A; Almási, G; Hebling, J

    2016-01-01

    Practical aspects of the robust method we recently proposed for producing few-cycle attosecond pulses with arbitrary waveform in the extreme ultraviolet spectral range are studied numerically. It is based on the undulator radiation of relativistic ultrathin electron layers produced by inverse free-electron laser process. Optimal conditions for nanobunching are given; attosecond pulse energy and waveform, and their stability are studied. For K=0.8 undulator parameter, carrier-envelope-phase stable pulses with >45 nJ energy and 80 as duration at 20 nm, and >250 nJ energy and 240 as duration at 60 nm are predicted with 31 mrad and 13 mrad phase stability, respectively.

  18. An electrophysiological dissociation between orbitofrontal reality filtering and context source monitoring.

    Science.gov (United States)

    Bouzerda-Wahlen, Aurélie; Nahum, Louis; Liverani, Maria Chiara; Guggisberg, Adrian G; Schnider, Armin

    2015-01-01

    Memory influences behavior in multiple ways. One important aspect is to remember in what precise context in the past a piece of information was acquired (context source monitoring). Another important aspect is to sense whether an upcoming thought, composed of fragments of memories, refers to present reality and can be acted upon (orbitofrontal reality filtering). Whether these memory control processes share common underlying mechanisms is unknown. Failures of both have been held accountable for false memories, including confabulation. Electrophysiological and imaging studies suggest a dissociation but used very different paradigms. In this study, we juxtaposed the requirements of context source monitoring and reality filtering within a unique continuous recognition task, which healthy participants performed while high-resolution evoked potentials were recorded. The mechanisms dissociated both behaviorally and electrophysiologically: Reality filtering induced a frontal positivity, absence of a specific electrocortical configuration, and posterior medial orbitofrontal activity at 200-300 msec. Context source monitoring had no electrophysiological expression in this early period. It was slower and less accurate than reality filtering and induced a prolonged positive potential over frontal leads starting at 400 msec. The study demonstrates a hitherto unrecognized separation between orbitofrontal reality filtering and source monitoring. Whereas deficient orbitofrontal reality filtering is associated with reality confusion in thinking, the behavioral correlates of deficient source monitoring should be verified with controlled experimental exploration.

  19. Laser sources for polarized electron beams in cw and pulsed accelerators

    CERN Document Server

    Hatziefremidis, A; Fraser, D; Avramopoulos, H

    1999-01-01

    We report the characterization of a high power, high repetition rate, mode-locked laser system to be used in continuous wave and pulsed electron accelerators for the generation of polarized electron beams. The system comprises of an external cavity diode laser and a harmonically mode-locked Ti:Sapphire oscillator and it can provide up to 3.4 W average power, with a corresponding pulse energy exceeding 1 nJ at 2856 MHz repetition rate. The system is tunable between 770-785 and 815-835 nm with two sets of diodes for the external cavity diode laser. (author)

  20. In-situ structural integrity evaluation for high-power pulsed spallation neutron source - Effects of cavitation damage on structural vibration

    Science.gov (United States)

    Wan, Tao; Naoe, Takashi; Futakawa, Masatoshi

    2016-01-01

    A double-wall structure mercury target will be installed at the high-power pulsed spallation neutron source in the Japan Proton Accelerator Research Complex (J-PARC). Cavitation damage on the inner wall is an important factor governing the lifetime of the target-vessel. To monitor the structural integrity of the target vessel, displacement velocity at a point on the outer surface of the target vessel is measured using a laser Doppler vibrometer (LDV). The measured signals can be used for evaluating the damage inside the target vessel because of cyclic loading and cavitation bubble collapse caused by pulsed-beam induced pressure waves. The wavelet differential analysis (WDA) was applied to reveal the effects of the damage on vibrational cycling. To reduce the effects of noise superimposed on the vibration signals on the WDA results, analysis of variance (ANOVA) and analysis of covariance (ANCOVA), statistical methods were applied. Results from laboratory experiments, numerical simulation results with random noise added, and target vessel field data were analyzed by the WDA and the statistical methods. The analyses demonstrated that the established in-situ diagnostic technique can be used to effectively evaluate the structural response of the target vessel.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-07-01

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

  2. CW/Pulsed H- ion beam generation with PKU Cs-free 2.45 GHz microwave driven ion source

    Science.gov (United States)

    Peng, S. X.; Ren, H. T.; Xu, Y.; Zhang, T.; Zhang, A. L.; Zhang, J. F.; Zhao, J.; Guo, Z. Y.; Chen, J. E.

    2015-04-01

    Circular accelerators used for positron emission tomography (PET, i.e. accelerator used for make radio isotopes) need several mA of CW H- ion beam for their routine operation. Other facilities, like Space Radio-Environment Simulate Assembly (SPRESA), require less than 10 mA pulsed mode H- beam. Caesium free negative hydrogen ion source is a good choice for those facilities because of its compact structure, easy operation and low cost. Up to now, there is no H- source able to produce very intense H- beams with important variation of the duty factor[1]. Recently, a new version of 2.45 GHz microwave H- ion source was designed at PKU, based on lessons learnt from the previous one. This non cesiated source is very compact thanks to its permanent magnet configuration. Special attention was paid on the design of the discharge chamber structure, electron dumping and extraction system. Source test to produce H- ion beams in pulsed and CW mode was carried out on PKU ion source test bench. In CW mode, a 10.8 mA/30keV H- beam with rms emittance about 0.16 π.mm.mrad has been obtained with only 500 W rf power. The power efficiency reaches 21 mA/kW. In pulsed mode with duty factor of 10% (100Hz/1ms), this compact source can easily deliver 20 mA H- ion beam at 35 keV with rms emittance about 0.2 π.mm.mrad when RF power is set at 2.2 kW (peak power). Several hour successive running operation in both modes and totaling more than 200 hours proves its high quality. The outside dimension of this new H- source body is ϕ116 mm × 124 mm, and the entire H- source infrastructure, including rf matching section, plasma chamber and extraction system, is ϕ310 × 180 mm. The high voltage region is limited with in a ϕ310 mm × 230 mm diagram. Details are given in this paper.

  3. Online tuning of impedance matching circuit for long pulse inductively coupled plasma source operation--an alternate approach.

    Science.gov (United States)

    Sudhir, Dass; Bandyopadhyay, M; Kraus, W; Gahlaut, A; Bansal, G; Chakraborty, A

    2014-01-01

    Impedance matching circuit between radio frequency (RF) generator and the plasma load, placed between them, determines the RF power transfer from RF generator to the plasma load. The impedance of plasma load depends on the plasma parameters through skin depth and plasma conductivity or resistivity. Therefore, for long pulse operation of inductively coupled plasmas, particularly for high power (∼100 kW or more) where plasma load condition may vary due to different reasons (e.g., pressure, power, and thermal), online tuning of impedance matching circuit is necessary through feedback. In fusion grade ion source operation, such online methodology through feedback is not present but offline remote tuning by adjusting the matching circuit capacitors and tuning the driving frequency of the RF generator between the ion source operation pulses is envisaged. The present model is an approach for remote impedance tuning methodology for long pulse operation and corresponding online impedance matching algorithm based on RF coil antenna current measurement or coil antenna calorimetric measurement may be useful in this regard.

  4. Visual perspective during remembering: ERP evidence of familiarity-based source monitoring.

    Science.gov (United States)

    Leynes, P Andrew; Askin, Ben; Landau, Joshua D

    2016-12-10

    Autobiographical recollections are accompanied by visual perspectives that can be either a view through the person's own eyes (first-person) or a view that integrates visual characteristics of the rememberer into the reconstructed scene (third-person). Some have argued that a third-person perspective serves as a coping mechanism allowing the person to distance themselves from details of painful memories. The study reported here created first- and third-person memories in a novel experimental paradigm. Later, participants discriminated between these perspectives on a source memory test while event-related potentials (ERPs) were recorded. Experimental evidence from the current study suggests that memories from different perspectives can be effectively modeled in the lab. Directly comparing first-person and third-person memories revealed no strong source memory or ERP differences; however, more first-person memories were recognized. Surprisingly, the modeling of the behavioral data using ROC curves and Dual Process Signal Detection (DPSD) measures of recollection and familiarity suggest that familiarity contributed to source judgments of both first- and third-person memories. The ERP data support this claim because the putative ERP correlate of familiarity (i.e., FN400) was observed during the source test. Because source monitoring tends to draw on recollection, evidence of familiarity-based source monitoring has been elusive, and these results support a key prediction of the Source Monitoring Framework (SMF) - that source decisions can be based on familiarity in some contexts (Johnson, Hashtroudi, & Lindsay, 1993; Mitchell & Johnson, 2009).

  5. Implementation of the Fissile Mass Flow Monitor Source Verification and Confirmation

    Energy Technology Data Exchange (ETDEWEB)

    Uckan, Taner [ORNL; March-Leuba, Jose A [ORNL; Powell, Danny H [ORNL; Nelson, Dennis [Sandia National Laboratories (SNL); Radev, Radoslav [Lawrence Livermore National Laboratory (LLNL)

    2007-12-01

    This report presents the verification procedure for neutron sources installed in U.S. Department of Energy equipment used to measure fissile material flow. The Fissile Mass Flow Monitor (FMFM) equipment determines the {sup 235}U fissile mass flow of UF{sub 6} gas streams by using {sup 252}Cf neutron sources for fission activation of the UF{sub 6} gas and by measuring the fission products in the flow. The {sup 252}Cf sources in each FMFM are typically replaced every 2 to 3 years due to their relatively short half-life ({approx} 2.65 years). During installation of the new FMFM sources, the source identity and neutronic characteristics provided by the manufacturer are verified with the following equipment: (1) a remote-control video television (RCTV) camera monitoring system is used to confirm the source identity, and (2) a neutron detection system (NDS) is used for source-strength confirmation. Use of the RCTV and NDS permits remote monitoring of the source replacement process and eliminates unnecessary radiation exposure. The RCTV, NDS, and the confirmation process are described in detail in this report.

  6. Maximum Alpha to Minimum Fission Pulse Amplitude for a Parallel-Plate and Hemispherical Cf-252 Ion-Chamber Instrumented Neutron Source

    Energy Technology Data Exchange (ETDEWEB)

    Oberer, R.B.

    2000-12-07

    In an instrumented Cf-252 neutron source, it is desirable to distinguish fission events which produce neutrons from alpha decay events. A comparison of the maximum amplitude of a pulse from an alpha decay with the minimum amplitude of a fission pulse shows that the hemispherical configuration of the ion chamber is superior to the parallel-plate ion chamber.

  7. Evidence of a plate-wide tectonic pressure pulse provided by extensometric monitoring in the Balkan Mountains (Bulgaria

    Directory of Open Access Journals (Sweden)

    Briestenský Miloš

    2015-10-01

    Full Text Available The EU-TecNet monitoring network uses customized three-dimensional extensometers to record transient deformations across individual faults. This paper presents the first results from two newly established monitoring points in the Balkan Mountains in Bulgaria. The data from Saeva Dupka, recorded across an EEN-WWS striking fault, show sinistral strike-slip along the fault and subsidence of the southern block. Much of the subsidence occurred around the time of the distal MW = 5.6 Pernik Earthquake. An important transient deformation event, which began in autumn 2012, was reflected by significant compression and following extension, across the monitored fault. The data from Bacho Kiro, recorded across a NE–SW striking fault, show sinistral strike-slip along the fault and subsidence of the north-western block. The same important deformation event was reflected by changes in the strike-slip, dip-slip, and horizontal opening/closing trends. These results have been compared to data from other monitoring points in the Western Carpathians, External Dinarides, and Tian Shan. Many of the sites show evidence of simultaneous displacement anomalies and this observation is interpreted as a reflection of the plate-wide propagation of a tectonic pressure pulse towards the end of 2012.

  8. Tunable vacuum-UV to visible ultrafast pulse source based on gas-filled Kagome-PCF.

    Science.gov (United States)

    Mak, Ka Fai; Travers, John C; Hölzer, Philipp; Joly, Nicolas Y; Russell, Philip St J

    2013-05-06

    An efficient and tunable 176-550 nm source based on the emission of resonant dispersive radiation from ultrafast solitons at 800 nm is demonstrated in a gas-filled hollow-core photonic crystal fiber (PCF). By careful optimization and appropriate choice of gas, informed by detailed numerical simulations, we show that bright, high quality, localized bands of UV light (relative widths of a few percent) can be generated at all wavelengths across this range. Pulse energies of more than 75 nJ in the deep-UV, with relative bandwidths of ~3%, are generated from pump pulses of a few μJ. Excellent agreement is obtained between numerical and experimental results. The effects of positive and negative axial pressure gradients are also experimentally studied, and the coherence of the deep-UV dispersive wave radiation numerically investigated.

  9. Simplification of the Plasma Load of Negative-Pulse-Bias Source Used in Arc Ion Plating

    Institute of Scientific and Technical Information of China (English)

    Dong QI; Ninghui WANG; Guoqiang LIN; Zhenfeng DING

    2003-01-01

    Based on the voltage and current fluctuating phenomenon in the arc plasma load under the negative-pulse-bias, usingthe plasma physics theory and analysis of computer simulation expatiates that the nature of plasma load in vacuumarc plasma is a capacitance

  10. Relationship between width of pulses and Lorentz factor expected from the light curve of fireball sources

    Institute of Scientific and Technical Information of China (English)

    Zhang Fu-Wen; Qin Yi-Ping

    2005-01-01

    Time profiles of many gamma-ray bursts consist of distinct pulses, which provides a possibility of characterizing the temporal structure of these bursts. We employ a simple model of highly symmetric fireballs to analyse the effect of the expansion speed on the light curve arising from different forms of local pulses. The relationship between the ratio r of the FWHM width of the rising phase of the light curve to that of the decaying phase and the Lorentz factor is investigated. The analysis shows that, when the rest frame radiation form is ignored, temporal profiles of the light curve arising from pulses of fireballs will not be affected by the expansion speed (that is, r is almost a constant) as long as the fireball expands relativistically. When the rest frame radiation form is taken into account, there will be a break in the curves of r - log Γ. The location of the break depends mainly on the adopted value of the rest frame peak frequency v0,p. One would reach almost the same result when a jet is considered. In addition, we utilize a sample of 48individual GRB pulses to check the relationship between the ratio r and the expansion speed Γ. We find no significant correlation between them, and this is consistent with the theoretical analysis.

  11. Pulse Power Performance of the Cygnus 1 and 2 Radiographic Sources

    Science.gov (United States)

    2013-06-01

    The Cygnus 1 machine was constructed and fielded at the Los Alamos National Laboratory to undergo pulsed power component and reliability testing and for...result of the cooperative effort of Titan PSD, Sandia National Laboratory, Los Alamos National Laboratory , and Bechtel Nevada.

  12. Two States CBR Modeling of Data Source in Dynamic Traffic Monitoring Sensor Networks

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Real traffic information was analyzed in the statistical characteristics and approximated as a Gaussian time series. A data source model, called two states constant bit rate (TSCBR), was proposed in dynamic traffic monitoring sensor networks. Analysis of autocorrelation of the models shows that the proposed TSCBR model matches with the statistical characteristics of real data source closely. To further verify the validity of the TSCBR data source model, the performance metrics of power consumption and network lifetime was studied in the evaluation of sensor media access control (SMAC) algorithm. The simulation results show that compared with traditional data source models, TSCBR model can significantly improve accuracy of the algorithm evaluation.

  13. Monitoring of conditions inside gas aggregation cluster source during production of Ti/TiOx nanoparticles

    Science.gov (United States)

    Kousal, J.; Kolpaková, A.; Shelemin, A.; Kudrna, P.; Tichý, M.; Kylián, O.; Hanuš, J.; Choukourov, A.; Biederman, H.

    2017-10-01

    Gas aggregation sources are nowadays rather widely used in the research community for producing nanoparticles. However, the direct diagnostics of conditions inside the source are relatively scarce. In this work, we focused on monitoring the plasma parameters and the composition of the gas during the production of the TiOx nanoparticles. We studied the role of oxygen in the aggregation process and the influence of the presence of the particles on the plasma. The construction of the source allowed us to make a 2D map of the plasma parameters inside the source.

  14. Photoacoustic & pulsed laser-doppler monitoring of blood concentration and perfusion in tissue

    OpenAIRE

    Kolkman, Roy Gerardus Maria

    2002-01-01

    In medicine there are situations that require continuous bedside monitoring of perfusion and blood volume. Such a situation can occur when children are born prematurely. Those children have a high risk to develop a handicap, which is most likely caused by cerebral damage due to impaired brain perfusion. Monitoring cerebral perfusion can provide information for preventive treatment. In this thesis we have explored the potential of photoacoustics and laser Doppler flowmetry for measurement of c...

  15. 150 keV accelerator as pulsed neutron source; Acelerador de 150 keV como fuente de neutrones pulsada

    Energy Technology Data Exchange (ETDEWEB)

    Cordero, F.

    1970-07-01

    The project of a 150 keV Cockcroft-Walton accelerator built at J.E.N. is described. Beam currents of more than 10 mA, with a neutron intensity of 10{sup 1}1 n.s{sup 1}, are obtained. Also, we report some research made in connection with that project. The role of the contamination in the vacuum system and the performance of the pumps and gauges pumping deuterium gas are studied. Sinusoidal pulses are employed as an analysis method of the discharge in the ion source and the performance of the extracting-focusing system. The parameters of the beam leaving the ion source have been determined; these are used to calculate the electrostatic lenses with the gaussian optics. Measurements concerning deuterium and tritium targets as neutron sources have been made and the processes affecting their practical service life are analyzed. (Author) 71 refs.

  16. Monitoring source water for microbial contamination: evaluation of water quality measures.

    Science.gov (United States)

    Plummer, Jeanine D; Long, Sharon C

    2007-08-01

    Watershed management programs often rely on monitoring for a large number of water quality parameters to define contaminant issues. While coliforms have traditionally been used to identify microbial contamination, these indicators cannot discriminate among potential contaminant sources. Microbial source tracking (MST) can provide the missing link that implicates the sources of contamination. The objective of this study was to use a weight-of-evidence approach (land use analysis using GIS, sanitary surveys, traditional water quality monitoring, and MST targets) to identify sources of pollution within a watershed that contains a raw drinking water source. For the study watersheds, statistical analyses demonstrated that one measure each of particulate matter (turbidity, particle counts), organic matter (total organic carbon, dissolved organic carbon, UV(254) absorbance), and indicator organisms (fecal coliforms, enterococci) were adequate for characterizing water quality. While these traditional parameters were useful for assessing overall water quality, they were not intended to differentiate between microbial sources at different locations. In contrast, the MST targets utilized (Rhodococcus coprophilus, sorbitol-fermenting Bifidobacteria, and male-specific coliphages) pinpointed specific sources of microbial pollution. However, these targets could not be used for routine monitoring due to a high percentage of non-detects.

  17. Power system monitoring and source control of the Space Station Freedom DC power system testbed

    Science.gov (United States)

    Kimnach, Greg L.; Baez, Anastacio N.

    1992-01-01

    Unlike a terrestrial electric utility which can purchase power from a neighboring utility, the Space Station Freedom (SSF) has strictly limited energy resources; as a result, source control, system monitoring, system protection, and load management are essential to the safe and efficient operation of the SSF Electric Power System (EPS). These functions are being evaluated in the DC Power Management and Distribution (PMAD) Testbed which NASA LeRC has developed at the Power System Facility (PSF) located in Cleveland, Ohio. The testbed is an ideal platform to develop, integrate, and verify power system monitoring and control algorithms. State Estimation (SE) is a monitoring tool used extensively in terrestrial electric utilities to ensure safe power system operation. It uses redundant system information to calculate the actual state of the EPS, to isolate faulty sensors, to determine source operating points, to verify faults detected by subsidiary controllers, and to identify high impedance faults. Source control and monitoring safeguard the power generation and storage subsystems and ensure that the power system operates within safe limits while satisfying user demands with minimal interruptions. System monitoring functions, in coordination with hardware implemented schemes, provide for a complete fault protection system. The objective of this paper is to overview the development and integration of the state estimator and the source control algorithms.

  18. Evaluation of coarse and fine particulate sources using a portable aerosol monitor in a desert community.

    Science.gov (United States)

    Phalen, Robert N; Coleman, Ted

    2012-08-01

    The purpose of this study was to use a portable aerosol monitor as a preliminary screening tool to identify local sources of coarse (PM(10-2.5)) and fine (PM(2.5)) particulate matter within the Coachella Valley, a low-elevation desert community. The portable aerosol monitor proved to be useful in identifying particle sources unique to the region, namely, sand dunes with sparse ground cover (vegetation), a river wash, and diesel truck and freight train traffic. The general limitations relate to discrepancies in the fraction of PM(10-2.5) when compared to regional air quality data and a lack of accurate mass-based data.

  19. Construction of a single/multiple wavelength RZ optical pulse source at 40 GHz by use of wavelength conversion in a high-nonlinearity DSF-NOLM

    DEFF Research Database (Denmark)

    Yu, Jianjun; Yujun, Qian; Jeppesen, Palle;

    2001-01-01

    A single or multiple wavelength RZ optical pulse source at 40 GHz is successfully obtained by using wavelength conversion in a nonlinear optical loop mirror consisting of high nonlinearity-dispersion shifted fiber.......A single or multiple wavelength RZ optical pulse source at 40 GHz is successfully obtained by using wavelength conversion in a nonlinear optical loop mirror consisting of high nonlinearity-dispersion shifted fiber....

  20. Monitoring light source for CMS lead tungstate crystal calorimeter at LHC

    CERN Document Server

    Zhang Liang Ying; Zhu, R Y; Liu, D T

    2001-01-01

    Light monitoring will serve as an intercalibration for Compact Muon Solenoid (CMS) lead tungstate crystals in situ at the Large Hadronic Collider, which is crucial for maintaining crystal calorimeter's subpercent constant term in the energy resolution. This paper presents the design of the CMS electromagnetic calorimeter monitoring light source and high-level distribution system. The correlations between variations of the light output and the transmittance for the CMS choice of yttrium-doped PbWO/sub 4/ crystals were investigated and were used to study monitoring linearity and sensitivity as a function of wavelength. The monitoring wavelength was determined so that a good linearity as well as adequate sensitivity can be achieved. The performance of a custom manufactured tunable laser system is presented. Issues related to monitoring precision are discussed. (12 refs).

  1. Monitoring light source for CMS lead tungstate crystal calorimeter at LHC

    CERN Document Server

    Li Yuan Zhang; Ren Yuan Zhu; Duncan, Liu

    2000-01-01

    Light monitoring will serve as an inter calibration for the CMS lead tungstate crystals in situ at LHC, which is crucial for maintaining the crystal calorimeter's sub percent constant term in energy resolution. This paper presents the design of the CMS ECAL monitoring light source and high level distribution system. The correlations between variations of the light output and the transmittance for the CMS choice of Y doped PbWO/sub 4/ crystals were investigated, and were used to study monitoring linearity and sensitivity as a function of the wavelength. The monitoring wavelength was determined so that a good linearity as well as adequate sensitivity can be achieved. The performance of a custom manufactured tunable laser system is presented. Issues related to monitoring precision are discussed. (13 refs).

  2. Monitoring light source for CMS lead tungstate crystal calorimeter at LHC

    CERN Document Server

    Zhang, L; Wei, Q; Zhu, R Y; Liu, D T

    2002-01-01

    Light monitoring will track variations of the calibration of the CMS lead tungstate crystals in situ at LHC, which is crucial for maintaining crystal calorimeter's subpercent constant term in the energy resolution. This paper presents the design of the CMS ECAL monitoring light source and high level distribution system. The correlations between variations of the light output and the transmittance for the CMS choice of yttrium doped PbWO/sub 4/ crystals were investigated, and were used to study monitoring linearity and sensitivity as a function of wavelength. The monitoring wavelength was determined so that a good linearity as well as adequate sensitivity can be achieved. The performance of a custom manufactured tunable laser system is presented. Issues related to monitoring precision are discussed. (13 refs).

  3. Monitoring light source for CMS lead tungstate crystal calorimeter at LHC

    CERN Document Server

    Zhang Li Yuan; Zhu Ren Yuan; Liu Dun Can

    2000-01-01

    Light monitoring will serve as an inter calibration for CMS lead tungstate crystals in situ at LHC, which is crucial for maintaining crystal calorimeter's sub percent constant term in the energy resolution. This paper presents the design of the CMS ECAL monitoring light source and high level distribution system. The correlations between variations of the light output and the transmittance for the CMS choice of Y doped PbWO//4 crystals were investigated, and were used to study monitoring linearity and sensitivity as a function of the wavelength. The monitoring wavelength was determined so that a good linearity as well as adequate sensitivity can be achieved. The performance of a custom manufactured tunable laser system is presented. Issues related to monitoring precision are discussed. 29 Refs.

  4. Battery-powered pulsed high density inductively coupled plasma source for pre-ionization in laboratory astrophysics experiments.

    Science.gov (United States)

    Chaplin, Vernon H; Bellan, Paul M

    2015-07-01

    An electrically floating radiofrequency (RF) pre-ionization plasma source has been developed to enable neutral gas breakdown at lower pressures and to access new experimental regimes in the Caltech laboratory astrophysics experiments. The source uses a customized 13.56 MHz class D RF power amplifier that is powered by AA batteries, allowing it to safely float at 3-6 kV with the electrodes of the high voltage pulsed power experiments. The amplifier, which is capable of 3 kW output power in pulsed (<1 ms) operation, couples electrical energy to the plasma through an antenna external to the 1.1 cm radius discharge tube. By comparing the predictions of a global equilibrium discharge model with the measured scalings of plasma density with RF power input and axial magnetic field strength, we demonstrate that inductive coupling (rather than capacitive coupling or wave damping) is the dominant energy transfer mechanism. Peak ion densities exceeding 5 × 10(19) m(-3) in argon gas at 30 mTorr have been achieved with and without a background field. Installation of the pre-ionization source on a magnetohydrodynamically driven jet experiment reduced the breakdown time and jitter and allowed for the creation of hotter, faster argon plasma jets than was previously possible.

  5. Importance of monitoring family members in establishing sources and pathways of lead in blood.

    Science.gov (United States)

    Gulson, B L; Mizon, K J; Korsch, M J; Howarth, D

    1996-10-11

    High precision lead isotope measurements were undertaken to establish the sources and pathways in blood and environmental samples of five families from the Broken Hill lead mining community, New South Wales, Australia. The five families were selected from 27 families investigated to illustrate the different sources and pathways of lead into blood and the importance of monitoring the whole family. The results illustrate that although the major source of lead is from the orebody, paint and petrol can be significant contributors to both house dust and blood leads. The results also show that the sources and pathways can be from the father's occupation and hence monitoring of families is important, especially in high risk locations. In two cases, the elevated blood leads in the children did not derive from their current residence but from other residences in the community.

  6. On the Exposure Limits for Extended Source Multiple Pulse Laser Exposures

    Science.gov (United States)

    2013-08-01

    Electrotechnical Commission (IEC) 60825-1, respectively], and of the International Commission on NonIonizing Radiation Protection (ICNIRP) laser exposure limit...of the three rules will be less intuitive. This paper presents an analysis of the proposed expo- sure limits for multiple pulse laser exposure to the...similar manner to the classification of laser products. The main goal of this paper is to identify and discuss cri- teria that can identify which of

  7. Effcient and pure femtosecond-pulse-length source of polarization-entangled photons

    CERN Document Server

    Weston, Morgan M; Wollmann, Sabine; Boston, Allen; Ho, Joseph; Shalm, Lynden K; Verma, Varun B; Allman, Michael S; Nam, Sae Woo; Patel, Raj B; Slussarenko, Sergei; Pryde, Geoff J

    2016-01-01

    We present a source of polarization entangled photon pairs based on spontaneous parametric downconversion engineered for frequency uncorrelated telecom photon generation. Our source provides photon pairs that display, simultaneously, the key properties for high-performance quantum information and fundamental quantum science tasks. Specifically, the source provides for high heralding efficiency, high quantum state purity and high entangled state fidelity at the same time. Among different tests we apply to our source we observe almost perfect non-classical interference between photons from independent sources with a visibility of $(100\\pm5)\\%$.

  8. Recent Performance and Ignition Tests of the pulsed SNS H- Source for 1-MW Neutron Production

    Energy Technology Data Exchange (ETDEWEB)

    Stockli, Martin P [ORNL; Han, Baoxi [ORNL; Murray, Jr, S N [ORNL; Pennisi, Terry R [ORNL; Piller, Chip [ORNL; Santana, Manuel [ORNL; Welton, Robert F [ORNL

    2015-01-01

    After acquiring several reliable spare targets, SNS ramped the beam power from 850 kW to 1.4 MW, which required an increase in H- beam pulse length from 0.88 to 1.0 ms at 60 Hz. This increase initially produced slow 2-MHz power ramp-ups and, after several weeks of uninterrupted operation, it produced plasma outages every time the pulse length was raised above ~0.95 ms. Similar outages were previously observed towards the end of long service cycles, which were believed to indicate that the breakdown voltage of the high purity hydrogen started to exceed the induced electric fields. In 2011 the RF was reconfigured to start with 10 cycles of 1.96 MHz, which yielded the shortest H- beam rise times and apparently eliminated those plasma outages. The new, pulse-length dependent outages were eliminated by increasing the initial frequency to 1.985 MHz. However, careful frequency studies are unable to justify this frequency. In addition, the paper discusses the issues and solutions for the electron-dump voltage, which starts to sag and become unstable after several weeks of high current operation.

  9. Counter-facing plasma focus system as a repetitive and/or long-pulse high energy density plasma source

    Science.gov (United States)

    Aoyama, Yutaka; Nakajima, Mitsuo; Horioka, Kazuhiko

    2009-11-01

    A plasma focus system composed of a pair of counter-facing coaxial plasma guns is proposed as a long-pulse and/or repetitive high energy density plasma source. A proof-of-concept experiment demonstrated that with an assist of breakdown and outer electrode connections, current sheets evolved into a configuration for stable plasma confinement at the center of the electrodes. The current sheets could successively compress and confine the high energy density plasma every half period of the discharge current, enabling highly repetitive light emissions in extreme ultraviolet region with time durations in at least ten microseconds.

  10. Intensity enhancement of cold neutrons from a coupled liquid-hydrogen moderator for pulsed cold neutron sources

    CERN Document Server

    Ogawa, Y; Kosugi, N; Iwasa, H; Furusaka, M; Watanabe, N

    1999-01-01

    In order to obtain higher cold neutron intensity from a coupled liquid-hydrogen moderator with a premoderator for pulsed cold neutron sources, we examined a partial enhancement method, namely, narrow beam extraction for both a flat liquid-hydrogen moderator and a single-groove one. Combined with the narrow beam extraction, which is especially suitable for small-angle scattering and neutron reflectometry experiments, a single-groove moderator provides higher intensity, by about 30%, than a flat-surface moderator at the region of interest on a viewed surface. The effect of double-side beam extraction from such moderators on the intensity gain factor is also discussed. (author)

  11. Monitoring respiration in wheezy preschool children by pulse oximetry plethysmogram analysis.

    Science.gov (United States)

    Wertheim, David; Olden, Cathy; Symes, Liz; Rabe, Heike; Seddon, Paul

    2013-09-01

    The aim of this study was to investigate whether respiratory information can be derived from pulse oximetry plethysmogram (pleth) recordings in acutely wheezy preschool children. A digital pulse oximeter was connected via 'Bluetooth' to a notebook computer in order to acquire pleth data. Low pass filtering and frequency analysis were used to derive respiratory rate from the pleth trace; the ratio of heart rate to respiratory rate (HR/RR) was also calculated. Recordings were obtained during acute wheezy episodes in 18 children of median age 31 months and follow-up recordings from 16 of the children were obtained when they were wheeze-free. For the acutely wheezy children, frequency analysis of the pleth waveform was within 10 breaths/min of clinical assessment in 25 of 29 recordings in 15 children. For the follow-up measurements, frequency analysis of the pleth waveform showed similarly good agreement in recordings on 15 of the 16 children. Respiratory rate was higher (p < 0.001), and HR/RR ratio was lower (p = 0.03) during acute wheeze than at follow-up. This study suggests that respiratory rate can be derived from pleth traces in wheezy preschool children.

  12. Basis of monitoring central blood pressure and hemodynamic parameters by peripheral arterial pulse waveform analyses.

    Science.gov (United States)

    Miyashita, Hiroshi; Katsuda, Shin-ichiro

    2013-01-01

    In hypertension clinics, central blood pressure (CBP) should be estimated, instead of directly measured, by the "signal processing" of a noninvasive peripheral pressure waveform. This paper deals with the data obtained in our three separate studies focusing on a major estimation method, i.e., radial artery late systolic shoulder pressure (rSBP2)-based CBP estimation. Study 1: Using a wave separation analysis of precise animal data of pressure wave transmission along the upper-limb arteries, we first demonstrate that pulse pressure amplification is largely attributable to local wave reflection alone. Study 2: A frequency component analysis of simultaneously recorded human central and radial artery pressure waveforms showed a predominance of lower (1st+2nd) harmonic components in determining the central augmentation peak amplitude. The features of a central pressure waveform, including its phase property, may contribute to the less-altered transmission of augmentation peak pressure to rSBP2. Study 3: Comparisons of noninvasive rSBP2 with direct or estimated central systolic blood pressure (cSBP) revealed broad agreement but also augmentation-dependent biases. Based on the features of the biases as well as the counterbalanced relationship between pulse pressure amplification and the transmission-induced alterations of augmentation peak amplitude observed in Study 2, we propose an improved cSBP estimate, SBPm, the simple arithmetic mean of rSBP2 and peripheral systolic blood pressure.

  13. Repetitively pulsed UV radiation source based on a run-away electron preionised diffuse discharge in nitrogen

    Science.gov (United States)

    Baksht, E. Kh; Burachenko, A. G.; Lomaev, M. I.; Panchenko, A. N.; Tarasenko, V. F.

    2015-04-01

    An extended repetitively pulsed source of spontaneous UV radiation is fabricated, which may also be used for producing laser radiation. Voltage pulses with an incident wave amplitude of up to 30 kV, a half-amplitude duration of ~4 ns and a rise time of ~2.5 ns are applied to a gap with a nonuniform electric field. For an excitation region length of 35 cm and a nitrogen pressure of 30 - 760 Torr, a diffusive discharge up to a pulse repetition rate of 2 kHz is produced without using an additional system for gap preionisation. An investigation is made of the plasma of the run-away electron preionised diffuse discharge. Using a CCD camera it is found that the dense diffused plasma fills the gap in a time shorter than 1 ns. X-ray radiation is recorded from behind the foil anode throughout the pressure range under study; a supershort avalanche electron beam is recorded by the collector electrode at pressures below 100 Torr.

  14. Repetitively pulsed UV radiation source based on a run-away electron preionised diffuse discharge in nitrogen

    Energy Technology Data Exchange (ETDEWEB)

    Baksht, E Kh; Burachenko, A G; Lomaev, M I; Panchenko, A N; Tarasenko, V F [Institute of High Current Electronics, Siberian Branch, Russian Academy of Sciences, Tomsk (Russian Federation)

    2015-04-30

    An extended repetitively pulsed source of spontaneous UV radiation is fabricated, which may also be used for producing laser radiation. Voltage pulses with an incident wave amplitude of up to 30 kV, a half-amplitude duration of ∼4 ns and a rise time of ∼2.5 ns are applied to a gap with a nonuniform electric field. For an excitation region length of 35 cm and a nitrogen pressure of 30 – 760 Torr, a diffusive discharge up to a pulse repetition rate of 2 kHz is produced without using an additional system for gap preionisation. An investigation is made of the plasma of the run-away electron preionised diffuse discharge. Using a CCD camera it is found that the dense diffused plasma fills the gap in a time shorter than 1 ns. X-ray radiation is recorded from behind the foil anode throughout the pressure range under study; a supershort avalanche electron beam is recorded by the collector electrode at pressures below 100 Torr. (laser applications and other topics in quantum electronics)

  15. Monitoring the activity variations of galactic X-ray sources with WATCH on EURECA

    DEFF Research Database (Denmark)

    Brandt, Søren; Lund, N.

    1995-01-01

    sources the observation periods extended over more than 100 days. A number of X-ray transients with durations between one and five days were discovered, and, additionally two long duration X-ray transients (GRS 1915+10 and GRO J0422+32) were active and could be monitored. Towards the end of the mission...

  16. Source Monitoring and Executive Function in 2.5- to 3-Year-Olds

    Science.gov (United States)

    Hala, Suzanne; McKay, Lee-Ann; Brown, Alisha M. B.; San Juan, Valerie

    2016-01-01

    Hala, Brown, McKay, and San Juan (2013) found that children as young as 2.5 years of age demonstrated high levels of accuracy when asked to recall whether they or the experimenter had carried out a particular action. In the research reported here, we examined the relation of early-emerging source monitoring to executive function abilities.…

  17. Narrow-band Borrmann multilayer filters for monitoring of EUV sources

    NARCIS (Netherlands)

    Barreaux, J.L.P.; Bastiaens, Hubertus M.J.; Kozhevnikov, I.V.; Bijkerk, Frederik; Boller, Klaus J.

    2014-01-01

    EUV sources currently under development for high volume manufacturing are based on hot plasmas that produce next to 13.5 nm also broadband blackbody radiation and out-of-band line emissions. For the accurate monitoring of the in-band (13.5 nm ± 2%) radiation power, narrow-band-pass filters are

  18. Palm top plasma focus device as a portable pulsed neutron source.

    Science.gov (United States)

    Rout, R K; Niranjan, Ram; Mishra, P; Srivastava, R; Rawool, A M; Kaushik, T C; Gupta, Satish C

    2013-06-01

    Development of a palm top plasma focus device generating (5.2 ± 0.8) × 10(4) neutrons∕pulse into 4π steradians with a pulse width of 15 ± 3 ns is reported for the first time. The weight of the system is less than 1.5 kg. The system comprises a compact capacitor bank, a triggered open air spark gap switch, and a sealed type miniature plasma focus tube. The setup is around 14 cm in diameter and 12.5 cm in length. The energy driver for the unit is a capacitor bank of four cylindrical commercially available electrolytic capacitors. Each capacitor is of 2 μF capacity, 4.5 cm in diameter, and 9.8 cm in length. The cost of each capacitor is less than US$ 10. The internal diameter and the effective length of the plasma focus unit are 2.9 cm and 5 cm, respectively. A DC to DC converter power supply powered by two rechargeable batteries charges the capacitor bank to the desired voltage and also provides a trigger pulse of -15 kV to the spark gap. The maximum energy of operation of the device is 100 J (8 μF, 5 kV, 59 kA) with deuterium gas filling pressure of 3 mbar. The neutrons have also been produced at energy as low as 36 J (3 kV) of operation. The neutron diagnostics are carried out with a bank of (3)He detectors and with a plastic scintillator detector. The device is portable, reusable, and can be operated for multiple shots with a single gas filling.

  19. The P{sub 1}-approximation for the Distribution of Neutrons from a Pulsed Source in Hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Claesson, A.

    1963-12-15

    The asymptotic distribution of neutrons from a pulsed, high energy source in an infinite moderator has been obtained earlier in a 'diffusion' approximation. In that paper the cross section was assumed to be constant over the whole energy region and the time derivative of the first moment was disregarded. Here, first, an analytic expression is obtained for the density in a P{sub 1} -approximation. However, the result is very complicated, and it is shown that an asymptotic solution can be found in a simpler way. By taking into account the low hydrogen scattering cross section at the source energy it follows that the space dependence of the distribution is less than that obtained earlier. The importance of keeping the time derivative of the first moment is further shown in a perturbation approximation.

  20. Coherent-pulse 2D crystallography using a free-electron laser x-ray source.

    Science.gov (United States)

    Mancuso, A P; Schropp, A; Reime, B; Stadler, L-M; Singer, A; Gulden, J; Streit-Nierobisch, S; Gutt, C; Grübel, G; Feldhaus, J; Staier, F; Barth, R; Rosenhahn, A; Grunze, M; Nisius, T; Wilhein, T; Stickler, D; Stillrich, H; Frömter, R; Oepen, H-P; Martins, M; Pfau, B; Günther, C M; Könnecke, R; Eisebitt, S; Faatz, B; Guerassimova, N; Honkavaara, K; Kocharyan, V; Treusch, R; Saldin, E; Schreiber, S; Schneidmiller, E A; Yurkov, M V; Weckert, E; Vartanyants, I A

    2009-01-23

    Coherent diffractive imaging for the reconstruction of a two-dimensional (2D) finite crystal structure with a single pulse train of free-electron laser radiation at 7.97 nm wavelength is demonstrated. This measurement shows an advance on traditional coherent imaging techniques by applying it to a periodic structure. It is also significant that this approach paves the way for the imaging of the class of specimens which readily form 2D, but not three-dimensional crystals. We show that the structure is reconstructed to the detected resolution, given an adequate signal-to-noise ratio.

  1. DC link current simulation of voltage source inverter with random space vector pulse width modulation

    Directory of Open Access Journals (Sweden)

    Chen Guoqiang

    2016-01-01

    Full Text Available Aiming at analysis complexity, a simulation model is built and presented to analyze and demonstrate the characteristics of the direct current (DC link current of the three-phase two-level inverter with the random space vector pulse width modulation (SVPWM strategy. The developing procedure and key subsystems of the simulation model are given in detail. Several experiments are done using the simulation model. The results verify the efficiency and convenience of the simulation model and show that the random SVPWM scheme, especially the random switching frequency scheme, can efficiently suppress the harmonic peaks of the DC link current.

  2. Neutron scattering studies of the dynamics of biopolymer-water systems using pulsed-source spectrometers

    Energy Technology Data Exchange (ETDEWEB)

    Middendorf, H.D. [Univ. of Oxford (United Kingdom); Miller, A. [Stirling Univ., Stirling (United Kingdom)

    1994-12-31

    Energy-resolving neutron scattering techniques provide spatiotemporal data suitable for testing and refining analytical models or computer simulations of a variety of dynamical processes in biomolecular systems. This paper reviews experimental work on hydrated biopolymers at ISIS, the UK Pulsed Neutron Facility. Following an outline of basic concepts and a summary of the new instrumental capabilities, the progress made is illustrated by results from recent experiments in two areas: quasi- elastic scattering from highly hydrated polysaccharide gels (agarose and hyaluronate), and inelastic scattering from vibrational modes of slightly hydrated collagen fibers.

  3. Sources of uncertainty in individual monitoring for photographic,TL and OSL dosimetry techniques

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Max S.; Silva, Everton R.; Mauricio, Claudia L.P., E-mail: max.das.ferreira@gmail.com, E-mail: everton@ird.gov.br, E-mail: claudia@ird.gov.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2015-07-01

    The identification of the uncertainty sources and their quantification is essential to the quality of any dosimetric results. If uncertainties are not stated for all dose measurements informed in the monthly dose report to the monitored radiation facilities, they need to be known. This study aims to analyze the influence of different sources of uncertainties associated with photographic, TL and OSL dosimetric techniques, considering the evaluation of occupational doses of whole-body exposure for photons. To identify the sources of uncertainty it was conducted a bibliographic review in specific documents that deal with operational aspects of each technique and the uncertainties associated to each of them. Withal, technical visits to individual monitoring services were conducted to assist in this identification. The sources of uncertainty were categorized and their contributions were expressed in a qualitative way. The process of calibration and traceability are the most important sources of uncertainties, regardless the technique used. For photographic dosimetry, the remaining important uncertainty sources are due to: energy and angular dependence; linearity of response; variations in the films processing. For TL and OSL, the key process for a good performance is respectively the reproducibility of the thermal and optical cycles. For the three techniques, all procedures of the measurement process must be standardized, controlled and reproducible. Further studies can be performed to quantify the contribution of the sources of uncertainty. (author)

  4. Development Of A Compact Photo-injector With RF-focusing Lens For Short Pulse Electron Source Application

    CERN Document Server

    Grabenhofer, Alexander; Shin, Young-Min

    2014-01-01

    For development of compact ultrafast electron source system, we are currently designing a short-pulse RF-gun with RF focusing structure by means of a series of comprehensive modeling analysis processes. EM design of a 2.5 cell resonant cavity with input coupler, acceleration dynamics of photo-emitted electron bunch, EM design of RF-lens with input coupler, and phasespace analysis of focused electron bunch are systematically examined with multi-physics simulators. All the features of the 2.856 GHz cavity geometry were precisely engineered for acceleration energies ranging from 100 keV to 500 keV (safety limited) to be powered by our 5 MW S-band klystron. The klystron (Thales TH2163) and modulator system (ScandiNova K1 turnkey system) were successfully installed and tested. Performance tests of the klystron system show peak output power > 5 MW, as per operation specifications. At the quasi-relativistic energies, the electron source is capable of generating 100fC -- 1 pC electron bunch with pulse duration close ...

  5. Low temperature plasmas created by photoionization of gases with intense radiation pulses from laser-produced plasma sources

    Science.gov (United States)

    Bartnik, A.; Pisarczyk, T.; Wachulak, P.; Chodukowski, T.; Fok, T.; Wegrzyński, Ł.; Kalinowska, Z.; Fiedorowicz, H.

    2016-12-01

    A comparative study of photoionized plasmas created by soft X-ray (SXR) and extreme ultraviolet (EUV) laser plasma sources was performed. The sources, employing high or low energy laser systems, utilized double-stream Xe/He gas-puff targets irradiated with laser pulses of different parameters. The SXR/EUV beams were used for irradiation of a gas stream, injected into a vacuum chamber synchronously with the radiation pulse. Photoionized plasmas produced this way in Ne gas emitted radiation in the SXR/EUV range. The corresponding spectra were dominated by emission lines originating from singly charged ions. Significant differences between spectra obtained in different experimental conditions concern specific transitions in Ne II ions. Creation of photoionized plasmas by SXR or EUV irradiation resulted in K-shell or L-shell emissions respectively. In case of the low energy system absorption spectra were measured additionally. In case of the high energy system, the electron density measurements were performed by laser interferometry, employing a femtosecond laser system. A maximum electron density reached the value of 2·1018cm-3. For the low energy system, a detection limit was too high for the interferometric measurements, thus only an upper estimation for electron density could be made.

  6. Frequency entanglement characterization of short-pulse pumped SPDC biphoton source with a Mach-Zehnder interferometer

    Science.gov (United States)

    Zhai, Yiwei; Dong, Ruifang; Li, Baihong; Quan, Runai; Wang, Mengmeng; Hou, Feiyan; Liu, Tao; Zhang, Shougang

    2017-06-01

    Frequency entangled biphoton sources have played an important role in quantum information. There are two key characteristics which determine the extent of their applications: the spectral indistinguishability and the degree of frequency entanglement. Previously, the spectral indistinguishability of the biphoton state is measured by the Hong-Ou-Mandel (HOM) interference visibility, whereas the degree of frequency entanglement is normally characterized with independent spectral measurements. However, these two quantum features have not been successfully measured with a single experimental setup. In this paper, we deduce the temporal distribution of a short-pulse pumped type-II spontaneous parametric down converted (SPDC) biphoton source and its relevant temporal entanglement parameter R t for operationally quantifying the degree of frequency entanglement. Furthermore, we theoretically and experimentally demonstrate, due to the inherent group delay, the difference between the signal and idler photons at the exit of the type-II nonlinear crystal, resulting in a HOM-shape dip at both sides of the center fringed envelope of the MZ interferometric coincidence diagram. By measuring the HOM-shape dip depth, the separation between the two sideband dips as well as the MZ fringed envelope width, both the spectral indistinguishability and the temporal entanglement parameter can thus be simultaneously quantified. This implementation provides us a unified and convenient method to characterize the frequency entanglement of the short-pulse pumped biphotons.

  7. Versatile microscope-coupled high-intensity pulsed light source for high-speed cine photomicrography of microactuators

    Science.gov (United States)

    Krehl, Peter; Engemann, Stephan; Rembe, Christian; Hofer, Eberhard P.

    1997-05-01

    A compact high-intensity pulsed light source has been developed in order to match a microdynamic test facility for high-speed motion analysis of micromechanical components. The test stand encompasses a universal microscope Zeiss Axioplan, the new light source and an electronic ultra high- speed multiple framing camera Hadland Imacon 468. The light source consists of a narrow cylindrical Xe-filled discharge tube, thus providing a locally stable emission. Since the small-size flashlamp easily fits into a standard microscope lamphousing, it allows to maintain the advantages of Koehler illumination as well as switching to other types of lamphousings. The flash tube is operated via an artificial asymmetric transmission line and delivers a square light pulse with a flash duration of 110 microsecond(s) FWHM and a peak intensity of 50 Med. The light source illuminates the object uniformly within the interesting time window; image shuttering is provided in the camera by gated micro-channel- plate intensifiers. To test the efficiency of the total system for various standard visualization methods (transmitted light, reflected light and differential interference contrast), microscopic still images have been taken at magnification up to 500X and with exposure times down to 10 ns. In addition, two microscopic darkfield methods which provide a high contrast but a low light intensity of the image, have been selected to test their applicability down to an exposure time of 100 ns. Two examples for real-time cinematography of high-speed phenomena in microactuators are shown: the bouncing behavior of an electro-magnetic microrelay and the bubble/jet formation of a thermal ink jet printhead.

  8. A sensor for monitoring pulse rate, respiration rhythm, and body movement in bed.

    Science.gov (United States)

    Yamana, Yusuke; Tsukamoto, Sosuke; Mukai, Koji; Maki, Hiromichi; Ogawa, Hidekuni; Yonezawa, Yoshiharu

    2011-01-01

    A non-constraint cardiac vibration, respiration, and body movement monitoring system has been developed. The sensor system is designed to be easily installable under an existing bed mattress. The sensor consists of a 40-kHz ultrasound transmitter and receiver pair. The transmitted ultrasound is reflected on the mattress' undersurface, and the amplitude of the received ultrasonic wave is modulated by the shape of the mattress, and parameters such as respiration, cardiac vibration, and movement. The physiological parameters can be extracted from the reflected ultrasound by an envelope detection circuit. To confirm the accuracy of the developed system, measurements were performed on 6 normal male subjects aged 25.0 ± 6.7 years, using 2 pocket spring coil mattresses and a polyurethane foam mattress. The results revealed that the physiological parameters were monitored with an 84.2% average accuracy for all mattresses when the subjects lay on the beds in the supine, lateral, and prone positions.

  9. Monitoring TeV Gamma-ray Sources for Flaring States with HAWC

    Science.gov (United States)

    Wisher, Ian; Weisgarber, Thomas; HAWC Collaboration

    2015-04-01

    The flux of many TeV gamma-ray emitters exhibits time variability. Detection of these flaring states across multiple wavelengths will lead to a better understanding of the acceleration processes occurring in the source. The High-Altitude Water Cherenkov (HAWC) Observatory is an extensive air-shower detector located near Pico de Orizaba in Mexico which is sensitive to TeV gamma rays. Designed as a survey instrument, the HAWC detector has a large field of view and nearly 100% uptime. This makes HAWC an ideal instrument to monitor sources for transient flaring states. We will present a method of monitoring sources using a Bayesian blocks algorithm to detect changes in the flux and report on the sensitivity of the method. We also discuss results from several bright AGN flares which occurred during the construction phase of HAWC.

  10. Doping He droplets by laser ablation with a pulsed supersonic jet source

    Energy Technology Data Exchange (ETDEWEB)

    Katzy, R.; Singer, M.; Izadnia, S.; LaForge, A. C., E-mail: aaron.laforge@physik.uni-freiburg.de; Stienkemeier, F. [Physikalisches Institut, Universität Freiburg, 79104 Freiburg (Germany)

    2016-01-15

    Laser ablation offers the possibility to study a rich number of atoms, molecules, and clusters in the gas phase. By attaching laser ablated materials to helium nanodroplets, one can gain highly resolved spectra of isolated species in a cold, weakly perturbed system. Here, we present a new setup for doping pulsed helium nanodroplet beams by means of laser ablation. In comparison to more well-established techniques using a continuous nozzle, pulsed nozzles show significant differences in the doping efficiency depending on certain experimental parameters (e.g., position of the ablation plume with respect to the droplet formation, nozzle design, and expansion conditions). In particular, we demonstrate that when the ablation region overlaps with the droplet formation region, one also creates a supersonic beam of helium atoms seeded with the sample material. The processes are characterized using a surface ionization detector. The overall doping signal is compared to that of conventional oven cell doping showing very similar dependence on helium stagnation conditions, indicating a comparable doping process. Finally, the ablated material was spectroscopically studied via laser induced fluorescence.

  11. Hybrid approaches to clinical trial monitoring: Practical alternatives to 100% source data verification

    Directory of Open Access Journals (Sweden)

    Sourabh De

    2011-01-01

    Full Text Available For years, a vast majority of clinical trial industry has followed the tenet of 100% source data verification (SDV. This has been driven partly by the overcautious approach to linking quality of data to the extent of monitoring and SDV and partly by being on the safer side of regulations. The regulations however, do not state any upper or lower limits of SDV. What it expects from researchers and the sponsors is methodologies which ensure data quality. How the industry does it is open to innovation and application of statistical methods, targeted and remote monitoring, real time reporting, adaptive monitoring schedules, etc. In short, hybrid approaches to monitoring. Coupled with concepts of optimum monitoring and SDV at site and off-site monitoring techniques, it should be possible to save time required to conduct SDV leading to more available time for other productive activities. Organizations stand to gain directly or indirectly from such savings, whether by diverting the funds back to the R&D pipeline; investing more in technology infrastructure to support large trials; or simply increasing sample size of trials. Whether it also affects the work-life balance of monitors who may then need to travel with a less hectic schedule for the same level of quality and productivity can be predicted only when there is more evidence from field.

  12. Nuclear Material Detection by One-Short-Pulse-Laser-Driven Neutron Source

    Energy Technology Data Exchange (ETDEWEB)

    Favalli, Andrea [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Aymond, F. [Univ. of Texas at Austin, TX (United States); Bridgewater, Jon S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Croft, Stephen [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Deppert, O. [Technische Universitat Darmstadt (Germany); Devlin, Matthew James [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Falk, Katerina [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Fernandez, Juan Carlos [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Gautier, Donald Cort [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Gonzales, Manuel A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Goodsell, Alison Victoria [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Guler, Nevzat [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hamilton, Christopher Eric [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hegelich, Bjorn Manuel [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Henzlova, Daniela [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Ianakiev, Kiril Dimitrov [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Iliev, Metodi [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Johnson, Randall Philip [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Jung, Daniel [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Kleinschmidt, Annika [Technische Universitat Darmstadt (Germany); Koehler, Katrina Elizabeth [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Pomerantz, Ishay [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Roth, Markus [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Santi, Peter Angelo [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Shimada, Tsutomu [Los Alamos National Laboratory; Swinhoe, Martyn Thomas [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Taddeucci, Terry Nicholas [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Wurden, Glen Anthony [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Palaniyappan, Sasikumar [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); McCary, E. [Univ. of Texas at Austin, TX (United States)

    2015-01-28

    Covered in the PowerPoint presentation are the following areas: Motivation and requirements for active interrogation of nuclear material; laser-driven neutron source; neutron diagnostics; active interrogation of nuclear material; and, conclusions, remarks, and future works.

  13. An ultrashort pulse ultra-violet radiation undulator source driven by a laser plasma wakefield accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Anania, M. P. [SUPA, Department of Physics, University of Strathclyde, Glasgow G4 0NG (United Kingdom); INFN, Laboratori Nazionali di Frascati, I-00044 Frascati (Italy); Brunetti, E.; Wiggins, S. M.; Grant, D. W.; Welsh, G. H.; Issac, R. C.; Cipiccia, S.; Shanks, R. P.; Manahan, G. G.; Aniculaesei, C.; Jaroszynski, D. A., E-mail: d.a.jaroszynski@strath.ac.uk [SUPA, Department of Physics, University of Strathclyde, Glasgow G4 0NG (United Kingdom); Geer, S. B. van der; Loos, M. J. de [Pulsar Physics, Burghstraat 47, 5614 BC Eindhoven (Netherlands); Poole, M. W.; Shepherd, B. J. A.; Clarke, J. A. [ASTeC, STFC, Daresbury Laboratory, Warrington WA4 4AD (United Kingdom); Gillespie, W. A. [SUPA, School of Engineering, Physics and Mathematics, University of Dundee, Dundee DD1 4HN (United Kingdom); MacLeod, A. M. [School of Computing and Creative Technologies, University of Abertay Dundee, Dundee DD1 1HG (United Kingdom)

    2014-06-30

    Narrow band undulator radiation tuneable over the wavelength range of 150–260 nm has been produced by short electron bunches from a 2 mm long laser plasma wakefield accelerator based on a 20 TW femtosecond laser system. The number of photons measured is up to 9 × 10{sup 6} per shot for a 100 period undulator, with a mean peak brilliance of 1 × 10{sup 18} photons/s/mrad{sup 2}/mm{sup 2}/0.1% bandwidth. Simulations estimate that the driving electron bunch r.m.s. duration is as short as 3 fs when the electron beam has energy of 120–130 MeV with the radiation pulse duration in the range of 50–100 fs.

  14. Improving the efficiency of a fluorescent Xe dielectric barrier light source using short pulse excitation

    Science.gov (United States)

    Beleznai, Sz; Mihajlik, G.; Maros, I.; Balázs, L.; Richter, P.

    2008-06-01

    Operation of a Xe dielectric barrier discharge lamp producing 147-172 nm VUV radiation is investigated both theoretically and experimentally. Xe gas pressure varies between 100 and 300 mbar, and the glass body of the lamp is coated with LAP (green) phosphor to convert radiation into the visible part of the spectrum. Simulation results predict improved discharge efficiencies reaching 67% when excited by a fast rise-time, short pulse (~200 ns) driving waveform. In this case most power deposited into the plasma efficiently produces Xe_2^\\ast excimers, while other energy dissipation processes (ion heating, e-Xe elastic collision) are kept at a low rate. Simulation and experimental results are compared in terms of discharge efficacy and show good agreement. A lamp efficacy value as high as 80 lm W-1 is demonstrated experimentally.

  15. Pt nanostructure electrodes pulse electrodeposited in PVP for electrochemical power sources.

    Science.gov (United States)

    Song, You-Jung; Oh, Jae-Kyung; Park, Kyung-Won

    2008-09-03

    In this work, we demonstrated that Pt nanostructure electrodes could be obtained by the pulse electrodeposition method in polyvinylpyrrolidone (PVP). The nanocrystal particles were confirmed by scanning electron microscopy, transmission electron microscopy and x-ray diffraction methods. The average size of Pt nanoparticles deposited in additive PVP with low and high molecular weight is 3.4 and 2.9 nm, respectively, whereas that of Pt electrodeposited without PVP is 360 nm. This means that the size of Pt nanoparticles can be controlled by PVP, resulting in an increased electrochemical surface area. The resulting Pt nanostructure electrodes showed such an improved performance for both direct methanol fuel cells and dye-sensitized solar cells.

  16. Pt nanostructure electrodes pulse electrodeposited in PVP for electrochemical power sources

    Energy Technology Data Exchange (ETDEWEB)

    Song, You-Jung; Oh, Jae-Kyung; Park, Kyung-Won [Department of Chemical and Environmental Engineering, Soongsil University, Seoul 156-743 (Korea, Republic of)], E-mail: kwpark@ssu.ac.kr

    2008-09-03

    In this work, we demonstrated that Pt nanostructure electrodes could be obtained by the pulse electrodeposition method in polyvinylpyrrolidone (PVP). The nanocrystal particles were confirmed by scanning electron microscopy, transmission electron microscopy and x-ray diffraction methods. The average size of Pt nanoparticles deposited in additive PVP with low and high molecular weight is 3.4 and 2.9 nm, respectively, whereas that of Pt electrodeposited without PVP is 360 nm. This means that the size of Pt nanoparticles can be controlled by PVP, resulting in an increased electrochemical surface area. The resulting Pt nanostructure electrodes showed such an improved performance for both direct methanol fuel cells and dye-sensitized solar cells.

  17. High ion charge states in a high-current, short-pulse, vacuum ARC ion sources

    Energy Technology Data Exchange (ETDEWEB)

    Anders, A.; Brown, I.; MacGill, R.; Dickinson, M. [Lawrence Berkeley National Lab., CA (United States)

    1996-08-01

    Ions of the cathode material are formed at vacuum arc cathode spots and extracted by a grid system. The ion charge states (typically 1-4) depend on the cathode material and only little on the discharge current as long as the current is low. Here the authors report on experiments with short pulses (several {mu}s) and high currents (several kA); this regime of operation is thus approaching a more vacuum spark-like regime. Mean ion charge states of up to 6.2 for tungsten and 3.7 for titanium have been measured, with the corresponding maximum charge states of up to 8+ and 6+, respectively. The results are discussed in terms of Saha calculations and freezing of the charge state distribution.

  18. Study on welding power source used in intelligent control system for weld pool shape in pulsed GTAW

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    This paper analyses the performance request of arc welding power source used in intelligent control of weld pool shape in pulsed GTAW, and develops a sample power source. The main circuit of the power source takes the structure of single ended inverter with two switches, and takes IGBTs as power switches. The working frequency of the inverter is set at 20(¨)kHz. The control circuit takes PWM circuit as center, and uses single chip computer to complete the manage functions such as the control of working sequence, setting and changing of the welding parameters, sensing of the welding states and communication with outside computer etc. The dynamic reacting time of the whole power is 1(¨)ms, the range of the output current is 5~250(¨)A, the precision of the output current reaches to 1 A. The power strikes arc by contacting workpiece under 5A, and have convenient interface with system computer. All above shows this power source is one with high performance.

  19. High-power, photofission-inducing bremsstrahlung source for intense pulsed active detection of fissile material

    Directory of Open Access Journals (Sweden)

    J. C. Zier

    2014-06-01

    Full Text Available Intense pulsed active detection (IPAD is a promising technique for detecting fissile material to prevent the proliferation of special nuclear materials. With IPAD, fissions are induced in a brief, intense radiation burst and the resulting gamma ray or neutron signals are acquired during a short period of elevated signal-to-noise ratio. The 8 MV, 200 kA Mercury pulsed-power generator at the Naval Research Laboratory coupled to a high-power vacuum diode produces an intense 30 ns bremsstrahlung beam to study this approach. The work presented here reports on Mercury experiments designed to maximize the photofission yield in a depleted-uranium (DU object in the bremsstrahlung far field by varying the anode-cathode (AK diode gap spacing and by adding an inner-diameter-reducing insert in the outer conductor wall. An extensive suite of diagnostics was fielded to measure the bremsstrahlung beam and DU fission yield as functions of diode geometry. Delayed fission neutrons from the DU proved to be a valuable diagnostic for measuring bremsstrahlung photons above 5 MeV. The measurements are in broad agreement with particle-in-cell and Monte Carlo simulations of electron dynamics and radiation transport. These show that with increasing AK gap, electron losses to the insert and outer conductor wall increase and that the electron angles impacting the bremsstrahlung converter approach normal incidence. The diode conditions for maximum fission yield occur when the gap is large enough to produce electron angles close to normal, yet small enough to limit electron losses.

  20. Fundamental neutron physics at a 1 MW long pulse spallation neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Greene, G.L.

    1995-12-31

    Modern neutron sources and modern neutron science share a common origin in mid twentieth century scientific investigations concerned with the study of the fundamental interactions between elementary particles. Since the time of that common origin, neutron science and the study of elementary particles have evolved into quite disparate disciplines. The neutron became recognized as a powerful tool for the study of condensed matter with modern neutron sources being primarily used (and primarily justified) as tools for condensed matter research. The study of elementary particles has, of course, led to the development of rather different tools and is now dominated by activities carried out at extremely high energies. Notwithstanding this trend, the study of fundamental interactions using neutrons has continued and remains a vigorous activity at many contemporary neutron sources. This research, like neutron scattering research, has benefited enormously by the development of modern high flux neutron facilities. Future sources, particularly high power spallation sources, offer exciting possibilities for the continuation of this program of research.

  1. Multi-frequency accelerating strategy for the contrast source inversion method of ultrasound waveform tomography using pulse data

    Science.gov (United States)

    Lin, Hongxiang; Azuma, Takashi; Qu, Xiaolei; Takagi, Shu

    2017-03-01

    In this work, we construct a multi-frequency accelerating strategy for the contrast source inversion (CSI) method using pulse data in the time domain. CSI is a frequency-domain inversion method for ultrasound waveform tomography that does not require the forward solver through the process of reconstruction. Several prior researches show that the CSI method has a good performance of convergence and accuracy in the low-center-frequency situation. In contrast, utilizing the high-center-frequency data leads to a high-resolution reconstruction but slow convergence on large numbers of grid. Our objective is to take full advantage of all low frequency components from pulse data with the high-center-frequency data measured by the diagnostic device. First we process the raw data in the frequency domain. Then multi-frequency accelerating strategy helps restart CSI in the current frequency using the last iteration result obtained from the lower frequency component. The merit of multi- frequency accelerating strategy is that computational burden decreases at the first few iterations. Because the low frequency component of dataset computes on the coarse grid with assuming a fixed number of points per wavelength. In the numerical test, the pulse data were generated by the K-wave simulator and have been processed to meet the computation of the CSI method. We investigate the performance of the multi-frequency and single-frequency reconstructions and conclude that the multi-frequency accelerating strategy significantly enhances the quality of the reconstructed image and simultaneously reduces the average computational time for any iteration step.

  2. Optical Cherenkov radiation by cascaded nonlinear interaction: an efficient source of few-cycle energetic near- to mid-IR pulses

    DEFF Research Database (Denmark)

    Bache, Morten; Bang, Ole; Zhou, Binbin;

    2011-01-01

    When ultrafast noncritical cascaded second-harmonic generation of energetic femtosecond pulses occur in a bulk lithium niobate crystal optical Cherenkov waves are formed in the near- to mid-IR. Numerical simulations show that the few-cycle solitons radiate Cherenkov (dispersive) waves in the λ = 2...... efficiency is up to 25%. Thus, optical Cherenkov waves formed with cascaded nonlinearities could become an efficient source of energetic near- to mid-IR few-cycle pulses....

  3. 40 CFR 141.211 - Special notice for repeated failure to conduct monitoring of the source water for Cryptosporidium...

    Science.gov (United States)

    2010-07-01

    ... conduct monitoring of the source water for Cryptosporidium and for failure to determine bin classification... Notification of Drinking Water Violations § 141.211 Special notice for repeated failure to conduct monitoring....701 must notify persons served by the water system that monitoring has not been completed as specified...

  4. Birth of an intense pulsed muon source, J-PARC MUSE

    Science.gov (United States)

    Miyake, Yasuhiro; Shimomura, Koichiro; Kawamura, Naritoshi; Strasser, Patrick; Makimura, Shunsuke; Koda, Akihiro; Fujimori, Hiroshi; Nakahara, Kazutaka; Kadono, Ryosuke; Kato, Mineo; Takeshita, Soshi; Nishiyama, Kusuo; Higemoto, Wataru; Ishida, Katsuhiko; Matsuzaki, Teiichiro; Matsuda, Yasuyuki; Nagamine, Kanetada

    2009-04-01

    The muon science facility (MUSE), along with neutron, hadron, and neutrino facilities, is one of the experimental areas of the J-PARC (Japan Proton Accelerator Research Complex) project, which was approved for construction between 2001 and 2008. The MUSE facility is located in the Materials and Life Science Facility (MLF), which is a building integrated to include both neutron and muon science programs. Construction of the MLF building was started at the beginning of 2004, and was recently completed at the end of the 2006 fiscal year. We have been working on the installation of the beamline components, expecting the first muon beam in the autumn of 2008. For Phase 1, we are planning to install one superconducting decay/surface channel with a modest-acceptance (about 40 mSr) pion injector, with an estimated surface muon (μ+) rate of 3×107/s and a beam size of 25 mm diameter, and a corresponding decay muon (μ+/μ-) rate of 106/s for 60 MeV/ c (up to 107/s for 120 MeV/ c) with a beam size of 50 mm diameter. These intensities correspond to more than 10-times what is available at the RIKEN/RAL muon facility, which currently possess the most intense pulsed muon beams in the world. In addition to Phase 1, we are planning to install, a surface muon channel with a modest-acceptance (about 50 mSr), mainly for experiments related to material sciences, and a super-omega muon channel with a large acceptance of 400 mSr. In the case of the super-omega muon channel, the goal is to extract 4×108 surface muons/s for the generation of ultra-slow muons and 1×107 negative cloud muons/s with a momentum of 30-60 MeV/ c. One of the important goals for this beamline is to generate intense ultra-slow muons at MUSE, utilizing an intense pulsed VUV laser system. 104-106 ultra-slow muons/s are expected, which will allow for an extension of μSR into the area of thin film and surface science. At this symposium, the current status of J-PARC MUSE will be reported.

  5. Pulse width modulated buck-boost five-level current source inverters

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Gao, F.; Loh, P.C.;

    2008-01-01

    This paper presents new five-level current source inverters (CSIs) with voltage/current buck-boost capability. Being different from the existing multilevel CSI, the proposed CSIs were first designed to regulate the flowing path of dc input current by controlling two additional active switches, re...

  6. VERITAS: a high-flux neutron reflectometer with vertical sample geometry for a long pulse spallation source

    Science.gov (United States)

    Mattauch, S.; Ioffe, A.; Lott, D.; Menelle, A.; Ott, F.; Medic, Z.

    2016-04-01

    An instrument concept of a reflectometer with a vertical sample geometry fitted to the long pulse structure of a spallation source, called “VERITAS” at the ESS, is presented. It focuses on designing a reflectometer with high intensity at the lowest possible background following the users' demand to investigate thin layers or interfacial areas in the sub-nanometer length scale. The high intensity approach of the vertical reflectometer fits very well to the long pulse structure of the ESS. Its main goal is to deliver as much usable intensity as possible at the sample position and be able to access a reflectivity range of 8 orders of magnitude and more. The concept assures that the reflectivity measurements can be performed in its best way to maximize the flux delivered to the sample. The reflectometer is optimized for studies of (magnetic) layers having thicknesses down to 5Å and a surface area of 1x1cm2. With reflectivity measurements the depth-resolved, laterally averaged chemical and magnetic profile can be investigated. By using polarised neutrons, additional vector information on the in-plane magnetic correlations (off-specular scattering at the pm length scale, GISANS at the nm length scale) can be studied. The full polarisation analysis could be used for soft matter samples to correct for incoherent scattering which is presently limiting neutron reflectivity studies to a reflectivity range on the order of 10-6.

  7. An Approach to Develop Embedded System For Web Based Monitoring & Controlling of Renewable Energy Sources

    Directory of Open Access Journals (Sweden)

    Akansha S. Fating

    2013-06-01

    Full Text Available The widespread application of Renewable Energy Sources (RESrequires centralized monitoring and controlling System. To makethese operations control room independent, there is need todevelop smart servers and web based applications. Cost is anessential factor of any embedded system design. This paperdiscusses a novel concept of designing of cost effective server/client embedded system Renewable Energy sources. Hereembedded server is developed with ARM9 controller loaded withwindows CE operating system. Low cost client are designedusing Atmega32 microcontroller with LAN connection. Server/client are connected in LAN system and server basedapplications has been developed to monitor/ controlling the clientoperation. The server has web based applications that can beaccessed via internet. Author has presented developed systemand results.

  8. Photon-monitoring attack on continuous-variable quantum key distribution with source in middle

    Science.gov (United States)

    Wang, Yijun; Huang, Peng; Guo, Ying; Huang, Dazu

    2014-12-01

    Motivated by a fact that the non-Gaussian operation may increase entanglement of an entangled system, we suggest a photon-monitoring attack strategy in the entanglement-based (EB) continuous-variable quantum key distribution (CVQKD) using the photon subtraction operations, where the entangled source originates from the center instead of one of the legal participants. It shows that an eavesdropper, Eve, can steal large information from participants after intercepting the partial beams with the photon-monitoring attach strategy. The structure of the proposed CVQKD protocol is useful in simply analyzing how quantum loss in imperfect channels can decrease the performance of the CVQKD protocol. The proposed attack strategy can be implemented under current technology, where a newly developed and versatile no-Gaussian operation can be well employed with the entangled source in middle in order to access to mass information in the EB CVQKD protocol, as well as in the prepare-and-measure (PM) CVQKD protocol.

  9. A global catalogue of large SO2 sources and emissions derived from the Ozone Monitoring Instrument

    Science.gov (United States)

    Fioletov, Vitali E.; McLinden, Chris A.; Krotkov, Nickolay; Li, Can; Joiner, Joanna; Theys, Nicolas; Carn, Simon; Moran, Mike D.

    2016-09-01

    Sulfur dioxide (SO2) measurements from the Ozone Monitoring Instrument (OMI) satellite sensor processed with the new principal component analysis (PCA) algorithm were used to detect large point emission sources or clusters of sources. The total of 491 continuously emitting point sources releasing from about 30 kt yr-1 to more than 4000 kt yr-1 of SO2 per year have been identified and grouped by country and by primary source origin: volcanoes (76 sources); power plants (297); smelters (53); and sources related to the oil and gas industry (65). The sources were identified using different methods, including through OMI measurements themselves applied to a new emission detection algorithm, and their evolution during the 2005-2014 period was traced by estimating annual emissions from each source. For volcanic sources, the study focused on continuous degassing, and emissions from explosive eruptions were excluded. Emissions from degassing volcanic sources were measured, many for the first time, and collectively they account for about 30 % of total SO2 emissions estimated from OMI measurements, but that fraction has increased in recent years given that cumulative global emissions from power plants and smelters are declining while emissions from oil and gas industry remained nearly constant. Anthropogenic emissions from the USA declined by 80 % over the 2005-2014 period as did emissions from western and central Europe, whereas emissions from India nearly doubled, and emissions from other large SO2-emitting regions (South Africa, Russia, Mexico, and the Middle East) remained fairly constant. In total, OMI-based estimates account for about a half of total reported anthropogenic SO2 emissions; the remaining half is likely related to sources emitting less than 30 kt yr-1 and not detected by OMI.

  10. Research Progress of Farmland Drought Monitoring and Prediction Based on Multi-Source Remote Sensing Data

    Science.gov (United States)

    Yang, Guijun; Yang, Hao; Jin, Xiuliang; Pignatti, Stefano; Casa, Raffaele; Pascucci, Simone; Silvesrtro, Paolo Cosmo

    2014-11-01

    Since the Kick-off of the Dragon-3 project Farmland Drought Monitoring and Prediction Based on Multi-source Remote Sensing Data (ID: 10448), our research focuses on three points including 1) the monitoring of key biophysical variables of crop and soil in farmland drought by optical and radar remote sensing data, 2) the risk assessment of farmland drought by time series remote sensing and meteorological data, and 3) the crop loss evaluation under farmland drought mainly based on AquaCrop crop model. Our study area is mainly located in Beijing, and Shaanxi Province (semi-arid region), China. Experiment campaign and data analysis were carried out and some new methods aiming at farmland drought monitoring and prediction were developed, which highlighting the importance of ESA-NRSCC Dragon cooperation.

  11. Iron-rich Oklahoma clays as a natural source of chromium in monitoring wells.

    Science.gov (United States)

    Scott, Dane; Apblett, Allen; Materer, Nicholas F

    2011-12-01

    Water samples, drawn from groundwater monitoring wells located southeast of Oklahoma City, OK, were found to contain elevated concentrations of total chromium with an apparent source localized to the area surrounding each well. Since these monitoring wells are located in areas with no historic chromium usage, industrial sources of chromium were ruled out. Water testing was performed on twelve monitoring wells in the area that historically had elevated total chromium concentrations ranging from 10-4900 micrograms per litre. Filtered water samples were found to be free of chromium contamination, indicating that the source of the chromium is the suspended solids. Analysis of these solids by acid digestion and a sequential extraction technique revealed that the chromium was primarily associated with iron-containing solids. X-ray diffraction identified goethite, an iron oxide hydroxide, as the dominant iron-containing phase in the suspended solids. The mineralogy in this region is dominated by interbedded red-bed sandstone and mudstone whose mineral content includes mixed-layer illite-smectite, hematite, goethite, gypsum and dolomite. Elemental analysis of soil samples collected as a function of depth in the locale of the monitoring wells indicated that the iron rich clays contain a natural source of chromium. The elevated levels of total chromium are most likely due to the dissolution of silica and alumina from the chromium containing iron clays in the basic well water, resulting in the release of fine suspended solids that naturally have high chromium concentrations. These results should be applicable to other areas containing iron-rich clays.

  12. Development of AN Open-Source Automatic Deformation Monitoring System for Geodetical and Geotechnical Measurements

    Science.gov (United States)

    Engel, P.; Schweimler, B.

    2016-04-01

    The deformation monitoring of structures and buildings is an important task field of modern engineering surveying, ensuring the standing and reliability of supervised objects over a long period. Several commercial hardware and software solutions for the realization of such monitoring measurements are available on the market. In addition to them, a research team at the Neubrandenburg University of Applied Sciences (NUAS) is actively developing a software package for monitoring purposes in geodesy and geotechnics, which is distributed under an open source licence and free of charge. The task of managing an open source project is well-known in computer science, but it is fairly new in a geodetic context. This paper contributes to that issue by detailing applications, frameworks, and interfaces for the design and implementation of open hardware and software solutions for sensor control, sensor networks, and data management in automatic deformation monitoring. It will be discussed how the development effort of networked applications can be reduced by using free programming tools, cloud computing technologies, and rapid prototyping methods.

  13. Pulsed-source time-resolved phosphorimetry: comparison of a commercial gated photomultiplier with a specially wired ungated photomultiplier.

    Science.gov (United States)

    Persvik, Øyvind; Melø, Thor Bernt; Naqvi, K Razi

    2013-06-01

    A common problem encountered in recording delayed light emission is that the signal of interest is preceded by a much more intense signal arising from prompt fluorescence. When a photomultiplier tube (PMT) is used as the photosensor in a pulsed-source phosphorimeter, two options are open to an experimenter who finds mechanical shutters inconvenient or impracticable and photon counting inappropriate: apply an electronic gate that suppresses the PMT gain for a brief period, or use a wiring scheme that enables the PMT to quickly regain normal operation after an intense burst of prompt emission. The performance of a squirrel-cage PMT that operates in the latter mode is compared with a new gateable PMT (Hamamatsu H11526 series) with a minimum gate time of 100 ns. The two detectors are found to provide practically the same temporal record of the delayed emission, but the ungated PMT is slightly superior in terms of recovery time and signal-to-noise ratio.

  14. Generation of ions in a pulsed ion source with an interface based on a polymer track membrane

    Science.gov (United States)

    Balakin, A. A.; Khidirov, S. G.; Buido, E. A.

    2016-10-01

    The time-of-flight spectra of ions generated during the extraction of negative ions from the KI solution in water-glycerin mixture by high-strength electric field pulses are studied using a source with an interface based on a polymer track membrane. It has been shown that the ions formed in secondary processes of bombardment of the membrane surface make a considerable contribution to the observed spectra. It has been found that the peaks of negative hydrogen ions have the highest intensity in the spectrum, indicating effective emission of these ions during the bombardment of polyethylene terephthalate by secondary ions with an energy of about 6 keV. The main trends in the modification of the membrane interface to reduce the fraction of secondary ions in the ion beam have been outlined.

  15. A simplified method for estimation of iron loss in wound toroidal cores energised by pulse width modulated voltage sources

    Science.gov (United States)

    Tutkun, Nedim; Moses, Anthony J.

    2004-12-01

    Recently the strip wound toroidal cores have increasingly been used in switching mode and uninterruptible power supplies for a wide range of industrial applications. Therefore, the prediction of iron loss increase in such magnetic cores energised by non-sinusoidal voltage excitation is important step in the design of electromagnetic devices. In this investigation, a loss increase was estimated by determination of unknown constants in a previously developed loss separation model using genetic algorithms. Also the skin effect of flux density was taken into account for estimation of power loss under pulse width modulated voltage sources. The results obtained are in good agreement with the measured results in wound toroids at various flux densities.

  16. A Distributed Monitoring and Control System for the Laser Ion Source RILIS at CERN-ISOLDE

    CERN Document Server

    AUTHOR|(SzGeCERN)715185; Richter, Detlef; Wendt, Klaus

    In this work, the implementation of the LabVIEW-based RILIS Equipment Acquisition and Control Toolset (REACT) software framework is documented, revised, and further developed to accomplish remotely operated in-source laser spectroscopy experiments at CERN-ISOLDE. The Resonance Ionization Laser Ion Source (RILIS) is an integral part of the radioactive ion beam user facility ISOLDE at CERN. Its task as an ion source is to ensure high isobaric purity and production efficiency of the ion beams that are generated for the various experimental setups of the facility. Reliable operation requires directing 3 pulsed laser beams, precisely wavelength-tuned and overlapped in time to a precision of 5 nanoseconds, to converge into a 3mm diameter ion source cavity located 25m away in an inaccessible radioactive environment. These stable conditions have to be maintained for up to 7 days at a time per experiment setup. Within recent years, the array of RILIS equipment and its need to interface with other experimental apparatu...

  17. Design of a finger base-type pulse oximeter

    Science.gov (United States)

    Lin, Bor-Shyh; Huang, Cheng-Yang; Chen, Chien-Yue; Lin, Jiun-Hung

    2016-01-01

    A pulse oximeter is a common medical instrument used for noninvasively monitoring arterial oxygen saturation (SpO2). Currently, the fingertip-type pulse oximeter is the prevalent type of pulse oximeter used. However, it is inconvenient for long-term monitoring, such as that under motion. In this study, a wearable and wireless finger base-type pulse oximeter was designed and implemented using the tissue optical simulation technique and the Monte Carlo method. The results revealed that a design involving placing the light source at 135°-165° and placing the detector at 75°-90° or 90°-105° yields the optimal conditions for measuring SpO2. Finally, the wearable and wireless finger base-type pulse oximeter was implemented and compared with the commercial fingertip-type pulse oximeter. The experimental results showed that the proposed optimal finger base-type pulse oximeter design can facilitate precise SpO2 measurement.

  18. A Radio Monitoring Survey of Ultra-Luminous X-Ray Sources

    CERN Document Server

    Koerding, E; Falcke, H

    2005-01-01

    We present the results of a radio monitoring campaign to search for radio emission from nearby ultra-luminous X-ray sources (ULXs). These sources are bright off-nuclear X-ray point sources with luminosities exceeding L_X > 10^39 erg/sec. A well-defined sample of the 9 nearest ULXs has been monitored eight times during 5 months with the Very Large Array in A and B configuration. Our limiting sensitivity is approximately 0.15 mJy (4 sigma) for radio flares and around 60 uJy for continuous emission. In M82 two ULXs seem to have coincident compact radio sources, which are probably supernova remnants. No continuous or flaring radio emission has been detected from any other ULX. Thus, ULXs do not generally emit steady-state radio emission above radio powers of 1.5 10^17 W/Hz. The non-detections of the continuous emission are consistent with beamed or unbeamed radio emission from accreting black holes of <= 10^3 Msol based on the radio/X-ray correlation. Other published radio detections (M82, NGC 5408) are also d...

  19. Temporal synchronization of GHz repetition rate electron and laser pulses for the optimization of a compact inverse-Compton scattering x-ray source

    CERN Document Server

    Hadmack, Michael R; Madey, John M J; Kowalczyk, Jeremy M D

    2014-01-01

    The operation of an inverse-Compton scattering source of x-rays or gamma-rays requires the precision alignment and synchronization of highly focused electron bunches and laser pulses at the collision point. The arrival times of electron and laser pulses must be synchronized with picosecond precision. We have developed an RF synchronization technique that reduces the initial timing uncertainty from 350 ps to less than 2 ps, greatly reducing the parameter space to be optimized while commissioning the x-ray source. We describe the technique and present measurements of its performance.

  20. Simulation of a suite of generic long-pulse neutron instruments to optimize the time structure of the European Spallation Source

    DEFF Research Database (Denmark)

    Lefmann, Kim; Klenø, Kaspar H.; Birk, Jonas Okkels;

    2013-01-01

    between 10 Hz and 25 Hz. The relative change in performance with time structure is given for each instrument, and an unweighted average is calculated. The performance of the instrument suite is proportional to (a) the peak flux and (b) the duty cycle to a power of approximately 0.3. This information......We here describe the result of simulations of 15 generic neutron instruments for the long-pulsed European Spallation Source. All instruments have been simulated for 20 different settings of the source time structure, corresponding to pulse lengths between 1 ms and 2 ms; and repetition frequencies...

  1. Compact sources for the generation of high-peak power wavelength-stabilized laser pulses in the picoseconds and nanoseconds ranges

    Science.gov (United States)

    Wenzel, H.; Klehr, A.; Schwertfeger, S.; Liero, A.; Hoffmann, Th.; Brox, O.; Thomas, M.; Erbert, G.; Tränkle, G.

    2012-03-01

    Diode lasers are ideally suited for the generation of optical pulses in the nanoseconds and picoseconds ranges by gainswitching, Q-switching or mode-locking. We have developed diode-laser based light sources where the pulses are spectrally stabilized and nearly-diffraction limited as required by many applications. Diffraction limited emission is achieved by a several microns wide ridge waveguide (RW), so that only the fundamental lateral mode should lase. Spectral stabilization is realized with a Bragg grating integrated into the semiconductor chip, resulting in distributed feedback (DFB) or distributed Bragg reflector (DBR) lasers. We obtained a peak power of 3.8W for 4ns long pulses using a gain-switched DFB laser and a peak power of more than 4W for 65ps long pulses using a three-section DBR laser. Higher peak powers of several tens of Watts can be reached by an amplification of the pulses with semiconductor optical amplifiers, which can be either monolithically or hybrid integrated with the master oscillators. We developed compact modules with a footprint of 4×5cm2 combining master oscillator, tapered power amplifier, beam-shaping optical elements and high-frequency electronics. In order to diminish the generation of amplified spontaneous emission between the pulses, the amplifier is modulated with short-pulses of high amplitude, too. Beyond the amplifier, we obtained a peak power of more than 10W for 4ns long pulses, a peak power of about 35W for 80ps long pulses and a peak power of 70W for 10ps long pulses at emission wavelengths around 1064nm.

  2. Characterization and application of a laser-driven intense pulsed neutron source using Trident

    Energy Technology Data Exchange (ETDEWEB)

    Vogel, Sven C. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-08-25

    A team of Los Alamos researchers supported a final campaign to use the Trident laser to produce neutrons, contributed their multidisciplinary expertise to experimentally assess if laser-driven neutron sources can be useful for MaRIE. MaRIE is the Laboratory’s proposed experimental facility for the study of matter-radiation interactions in extremes. Neutrons provide a radiographic probe that is complementary to x-rays and protons, and can address imaging challenges not amenable to those beams. The team's efforts characterize the Laboratory’s responsiveness, flexibility, and ability to apply diverse expertise where needed to perform successful complex experiments.

  3. Space Vector Pulse Width Modulation Scheme for a Seven-Phase Voltage Source Inverter

    Directory of Open Access Journals (Sweden)

    Mohd. Arif Khan

    2011-09-01

    Full Text Available This paper analyses a simple space vector PWM (SVPWM scheme for a seven-phase voltage source inverter. At first the conventional method of producing sinusoidal output voltage  by utilizing six active and a zero space vectors are used to synthesis the input reference and then new PWM scheme called time equivalent space vector PWM is presented.  A comparison of the proposed scheme with the conventional scheme is presented based on various performance indices. Extensive Simulation results are provided to validate the findings

  4. Sequential optimal monitoring network design and iterative spatial estimation of pollutant concentration for identification of unknown groundwater pollution source locations.

    Science.gov (United States)

    Prakash, Om; Datta, Bithin

    2013-07-01

    One of the difficulties in accurate characterization of unknown groundwater pollution sources is the uncertainty regarding the number and the location of such sources. Only when the number of source locations is estimated with some degree of certainty that the characterization of the sources in terms of location, magnitude, and activity duration can be meaningful. A fairly good knowledge of source locations can substantially decrease the degree of nonuniqueness in the set of possible aquifer responses to subjected geochemical stresses. A methodology is developed to use a sequence of dedicated monitoring network design and implementation and to screen and identify the possible source locations. The proposed methodology utilizes a combination of spatial interpolation of concentration measurements and simulated annealing as optimization algorithm for optimal design of the monitoring network. These monitoring networks are to be designed and implemented sequentially. The sequential design is based on iterative pollutant concentration measurement information from the sequentially designed monitoring networks. The optimal monitoring network design utilizes concentration gradient information from the monitoring network at previous iteration to define the objective function. The capability of the feedback information based iterative methodology is shown to be effective in estimating the source locations when no such information is initially available. This unknown pollution source locations identification methodology should be very useful as a screening model for subsequent accurate estimation of the unknown pollution sources in terms of location, magnitude, and activity duration.

  5. Open Source Based Sensor Platform for Mobile Environmental Monitoring and Data Acquisition

    Science.gov (United States)

    Schima, Robert; Goblirsch, Tobias; Misterek, René; Salbach, Christoph; Schlink, Uwe; Francyk, Bogdan; Dietrich, Peter; Bumberger, Jan

    2016-04-01

    The impact of global change, urbanization and complex interactions between humans and the environment show different effects on different scales. However, the desire to obtain a better understanding of ecosystems and process dynamics in nature accentuates the need for observing these processes in higher temporal and spatial resolutions. Especially with regard to the process dynamics and heterogeneity of urban areas, a comprehensive monitoring of these effects remains to be a challenging issue. Open source based electronics and cost-effective sensors are offering a promising approach to explore new possibilities of mobile data acquisition and innovative strategies and thereby support a comprehensive ad-hoc monitoring and the capturing of environmental processes close to real time. Accordingly, our project aims the development of new strategies for mobile data acquisition and real-time processing of user-specific environmental data, based on a holistic and integrated process. To this end, the concept of our monitoring system covers the data collection, data processing and data integration as well as the data provision within one infrastructure. This ensures a consistent data stream and a rapid data processing. However, the overarching goal is the provision of an integrated service instead of lengthy and arduous data acquisition by hand. Therefore, the system also serves as a data acquisition assistant and gives guidance during the measurements. In technical terms, our monitoring system consists of mobile sensor devices, which can be controlled and managed by a smart phone app (Android). At the moment, the system is able to acquire temperature and humidity in space (GPS) and time (real-time clock) as a built in function. In addition, larger system functionality can be accomplished by adding further sensors for the detection of e.g. fine dust, methane or dissolved organic compounds. From the IT point of view, the system includes a smart phone app and a web service for

  6. Radio pulse search and X-Ray monitoring of SAX J1808.4-3658: What Causes its Orbital Evolution?

    CERN Document Server

    Patruno, Alessandro; Kuiper, Lucien; Bult, Peter; Hessels, Jason; Knigge, Christian; King, Andrew R; Wijnands, Rudy; van der Klis, Michiel

    2016-01-01

    The accreting millisecond X-ray pulsar (AMXP) SAX J1808.4-3658, shows a peculiar orbital evolution that proceeds at a much faster pace than predicted by conservative binary evolution models. It is important to identify the underlying mechanism responsible for this behavior because it can help to understand how this system evolves. It has also been suggested that, when in quiescence, SAX J1808.4-3658 turns on as a radio pulsar, a circumstance that might provide a link between AMXPs and black-widow radio pulsars. In this work we report the results of a deep radio pulsation search at 2 GHz using the Green Bank Telescope in August 2014 and an X-ray monitoring of the 2015 outburst with Chandra, Swift, and INTEGRAL. In particular, we present the X-ray timing analysis of a 30-ks Chandra observation executed during the 2015 outburst. We detect no radio pulsations, and place the strongest limit to date on the pulsed radio flux density of any AMXP. We also find that the orbit of SAX J1808.4-3658 continues evolving at a...

  7. Feasibility Study and Design of a Wearable System-on-a-Chip Pulse Radar for Contactless Cardiopulmonary Monitoring

    Directory of Open Access Journals (Sweden)

    Domenico Zito

    2008-01-01

    Full Text Available A new system-on-a-chip radar sensor for next-generation wearable wireless interface applied to the human health care and safeguard is presented. The system overview is provided and the feasibility study of the radar sensor is presented. In detail, the overall system consists of a radar sensor for detecting the heart and breath rates and a low-power IEEE 802.15.4 ZigBee radio interface, which provides a wireless data link with remote data acquisition and control units. In particular, the pulse radar exploits 3.1–10.6 GHz ultra-wideband signals which allow a significant reduction of the transceiver complexity and then of its power consumption. The operating principle of the radar for the cardiopulmonary monitoring is highlighted and the results of the system analysis are reported. Moreover, the results obtained from the building-blocks design, the channel measurement, and the ultra-wideband antenna realization are reported.

  8. Characterization of continuous and pulsed emission modes of a hybrid micro focus x-ray source for medical imaging applications

    Science.gov (United States)

    Ghani, Muhammad U.; Wong, Molly D.; Ren, Liqiang; Wu, Di; Zheng, Bin; Rong, John. X.; Wu, Xizeng; Liu, Hong

    2017-05-01

    The aim of this study was to quantitatively characterize a micro focus x-ray tube that can operate in both continuous and pulsed emission modes. The micro focus x-ray source (Model L9181-06, Hamamatsu Photonics, Japan) has a varying focal spot size ranging from 16 μm to 50 μm as the source output power changes from 10 to 39 W. We measured the source output, beam quality, focal spot sizes, kV accuracy, spectra shapes and spatial resolution. Source output was measured using an ionization chamber for various tube voltages (kVs) with varying current (μA) and distances. The beam quality was measured in terms of half value layer (HVL), kV accuracy was measured with a non-invasive kV meter, and the spectra was measured using a compact integrated spectrometer system. The focal spot sizes were measured using a slit method with a CCD detector with a pixel pitch of 22 μm. The spatial resolution was quantitatively measured using the slit method with a CMOS flat panel detector with a 50 μm pixel pitch, and compared to the qualitative results obtained by imaging a contrast bar pattern. The focal spot sizes in the vertical direction were smaller than that of the horizontal direction, the impact of which was visible when comparing the spatial resolution values. Our analyses revealed that both emission modes yield comparable imaging performances in terms of beam quality, spectra shape and spatial resolution effects. There were no significantly large differences, thus providing the motivation for future studies to design and develop stable and robust cone beam imaging systems for various diagnostic applications.

  9. Effect of double false pulses in calibrated neutron coincidence collar during measuring time-correlated neutrons from PuBe neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Tam Cong, E-mail: tam.nguyen.cong@energia.mta.hu; Huszti, Jozsef; Nguyen, Quan Van

    2015-09-01

    Effect of double false pulses of preamplifiers in neutron coincidence collar was investigated to explain non-parallel shape of calibrated D/S–M{sub Pu} curves of two commercial neutron coincidence collars, JCC-31 and JCC-13. Two curves, which were constructed from D/S ratio (doubles and singles count rate), and Pu content M{sub Pu}, of the same set of secondary standard PuBe neutron sources, should be parallel. Non-parallelism rises doubt about usability of the method based on this curve for determination of Pu content in PuBe neutron sources. We have shown in three steps that the problem originates from double false pulses of preamplifiers in JCC-13. First we used a pulse train diagram for analyzing the non-parallel shape, second we used Rossi-Alpha distribution measured by pulse train recorder developed in our institute and finally, we investigated the effect of inserted noise pulses. This implies a new type of QA test option in traditional multiplicity shift registers for excluding presence of double false pulses.

  10. Pulsed, all solid-state light source in the visible spectral region based on non-linear cavity dumping

    DEFF Research Database (Denmark)

    Tidemand-Lichtenberg, Peter; Andersen, Martin; Johansson, Sandra

    We propose a novel generic approach for generation of pulsed light in the visible spectrum, based on SFG between the high circulating intra-cavity power of a high finesse CW laser and a single-passed pulsed laser....

  11. Monitoring of a mixed land use catchment for pollutant source characterisation.

    Science.gov (United States)

    Liu, An; Carroll, Steven; Dawes, Les; Goonetilleke, Ashantha

    2017-07-01

    Protection of surface water quality is a key driver in catchment management, particularly for areas undergoing land use change. Changing land use can result in the input of a range of pollutants to surface waters, resulting in water quality impairment, leading to eutrophication and the appearance of algae blooms. This study investigated a mixed land use coastal catchment by undertaking extensive field sampling and data analysis for pollutant source characterisation. The objective was to contribute to a greater understanding of pollutant inputs to surface water resources and for effective catchment management. Based on data analysis results, a diversity of pollutant sources was noted, including both natural areas and areas subject to anthropogenic activities such as agriculture and urban developments, with agricultural areas being comparatively more significant in exporting nutrients. Additionally, pollutant inputs into estuarine and freshwater areas were found to have specific characteristics influenced by land use. The pollutant inputs from these sources were found to be significantly affected by seasonal factors, with the dominant pollutant sources differing between the wet and dry seasons. This underlines the importance of taking seasonal factors into account in the development of effective catchment management strategies. Based on the study outcomes, a critical point monitoring program was developed with a focus on preventing algae blooms. This will allow the development of a decentralised catchment management strategy where resource-efficient monitoring of critical pollutant parameters at key locations can be undertaken for minimising the risk from algae blooms, rather than implementing a whole of catchment and resource-demanding large-scale monitoring program.

  12. Pulsed, all solid-state light source in the visible spectral region based on non-linear cavity dumping

    DEFF Research Database (Denmark)

    Tidemand-Lichtenberg, Peter; Andersen, Martin; Johansson, Sandra

    We propose a novel generic approach for generation of pulsed light in the visible spectrum, based on SFG between the high circulating intra-cavity power of a high finesse CW laser and a single-passed pulsed laser.......We propose a novel generic approach for generation of pulsed light in the visible spectrum, based on SFG between the high circulating intra-cavity power of a high finesse CW laser and a single-passed pulsed laser....

  13. Demonstration of a long pulse X-ray source at the National Ignition Facility

    Science.gov (United States)

    May, M. J.; Opachich, Y. P.; Kemp, G. E.; Colvin, J. D.; Barrios, M. A.; Widmann, K. W.; Fournier, K. B.; Hohenberger, M.; Albert, F.; Regan, S. P.

    2017-04-01

    A long duration high fluence x-ray source has been developed at the National Ignition Facility (NIF). The target was a 14.4 mm tall, 4.1 mm diameter, epoxy walled, gas filled pipe. Approximately 1.34 MJ from the NIF laser was used to heat the mixture of (55:45) Kr:Xe at 1.2 atm (˜5.59 mg/cm3) to emit in a fairly isotropic radiant intensity of 400-600 GW/sr from the Ephoton = 3-7 keV spectral range for a duration of ≈ 14 ns. The HYDRA simulated radiant intensities were in reasonable agreement with experiments but deviated at late times.

  14. Laser-driven high-power X- and gamma-ray ultra-short pulse source

    CERN Document Server

    Esirkepov, Timur Zh; Zhidkov, Alexei G; Pirozhkov, Alexander S; Kando, Masaki

    2008-01-01

    A novel ultra-bright high-intensity source of X-ray and gamma radiation is suggested. It is based on the double Doppler effect, where a relativistic flying mirror reflects a counter-propagating electromagnetic radiation causing its frequency multiplication and intensification, and on the inverse double Doppler effect, where the mirror acquires energy from an ultra-intense co-propagating electromagnetic wave. The role of the flying mirror is played by a high-density thin plasma slab accelerating in the radiation pressure dominant regime. Frequencies of high harmonics generated at the flying mirror by a relativistically strong counter-propagating radiation undergo multiplication with the same factor as the fundamental frequency of the reflected radiation, approximately equal to the quadruple of the square of the mirror Lorentz factor.

  15. Laser-driven high-power X- and γ-ray ultra-short pulse source

    Science.gov (United States)

    Esirkepov, Timur Zh.; Bulanov, Sergei V.; Pirozhkov, Alexander S.; Kando, Masaki; Zhidkov, Alexei G.

    2009-07-01

    A novel ultra-bright high-intensity source of X-ray and gamma radiation is suggested. It is based on the double Doppler effect, where a relativistic flying mirror reflects counter-propagating electromagnetic radiation causing its frequency multiplication and intensification, and on the inverse double Doppler effect, where the mirror acquires energy from an ultra-intense co-propagating electromagnetic wave. The role of the flying mirror is played by a high-density thin plasma slab accelerating in the radiation pressure dominant regime. Frequencies of high harmonics generated at the flying mirror by relativistically strong counter-propagating radiation undergo multiplication with the same factor as the fundamental frequency of the reflected radiation, approximately equal to the quadruple of the square of the mirror Lorentz factor.

  16. LOW COST ANALYZER FOR THE DETERMINATION OF PHOSPHORUS BASED ON OPEN-SOURCE HARDWARE AND PULSED FLOWS

    Directory of Open Access Journals (Sweden)

    Pablo González

    2016-04-01

    Full Text Available The need for automated analyzers for industrial and environmental samples has triggered the research for new and cost-effective strategies of automation and control of analytical systems. The widespread availability of open-source hardware together with novel analytical methods based on pulsed flows have opened the possibility of implementing standalone automated analytical systems at low cost. Among the areas that can benefit from this approach are the analysis of industrial products and effluents and environmental analysis. In this work, a multi-pumping flow system is proposed for the determination of phosphorus in effluents and polluted water samples. The system employs photometric detection based on the formation of molybdovanadophosphoric acid, and the fluidic circuit is built using three solenoid micropumps. The detection is implemented with a low cost LED-photodiode photometric detection system and the whole system is controlled by an open-source Arduino Uno microcontroller board. The optimization of the timing to ensure the color development and the pumping cycle is discussed for the proposed implementation. Experimental results to evaluate the system behavior are presented verifying a linear relationship between the relative absorbance and the phosphorus concentrations for levels as high as 50 mg L-1.

  17. Design and optimization of a modular setup for measurements of three-dimensional spin polarization with ultrafast pulsed sources

    Science.gov (United States)

    Pincelli, T.; Petrov, V. N.; Brajnik, G.; Ciprian, R.; Lollobrigida, V.; Torelli, P.; Krizmancic, D.; Salvador, F.; De Luisa, A.; Sergo, R.; Gubertini, A.; Cautero, G.; Carrato, S.; Rossi, G.; Panaccione, G.

    2016-03-01

    ULTRASPIN is an apparatus devoted to the measurement of the spin polarization (SP) of electrons ejected from solid surfaces in a UHV environment. It is designed to exploit ultrafast light sources (free electron laser or laser high harmonic generation) and to perform (photo)electron spin analysis by an arrangement of Mott scattering polarimeters that measure the full SP vector. The system consists of two interconnected UHV vessels: one for surface science sample cleaning treatments, e-beam deposition of ultrathin films, and low energy electron diffraction/AES characterization. The sample environment in the polarimeter allows for cryogenic cooling and in-operando application of electric and magnetic fields. The photoelectrons are collected by an electrostatic accelerator and transport lens that form a periaxial beam that is subsequently directed by a Y-shaped electrostatic deflector to either one of the two orthogonal Mott polarimeters. The apparatus has been designed to operate in the extreme conditions of ultraintense single-X-ray pulses as originated by free electron lasers (up to 1 kHz), but it allows also for the single electron counting mode suitable when using statistical sources such as synchrotron radiation, cw-laser, or e-gun beams (up to 150 kcps).

  18. Characteristics of temperature rise in variable inductor employing magnetorheological fluid driven by a high-frequency pulsed voltage source

    Science.gov (United States)

    Lee, Ho-Young; Kang, In Man; Shon, Chae-Hwa; Lee, Se-Hee

    2015-05-01

    A variable inductor with magnetorheological (MR) fluid has been successfully applied to power electronics applications; however, its thermal characteristics have not been investigated. To evaluate the performance of the variable inductor with respect to temperature, we measured the characteristics of temperature rise and developed a numerical analysis technique. The characteristics of temperature rise were determined experimentally and verified numerically by adopting a multiphysics analysis technique. In order to accurately estimate the temperature distribution in a variable inductor with an MR fluid-gap, the thermal solver should import the heat source from the electromagnetic solver to solve the eddy current problem. To improve accuracy, the B-H curves of the MR fluid under operating temperature were obtained using the magnetic property measurement system. In addition, the Steinmetz equation was applied to evaluate the core loss in a ferrite core. The predicted temperature rise for a variable inductor showed good agreement with the experimental data and the developed numerical technique can be employed to design a variable inductor with a high-frequency pulsed voltage source.

  19. Characteristics of temperature rise in variable inductor employing magnetorheological fluid driven by a high-frequency pulsed voltage source

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ho-Young; Kang, In Man, E-mail: imkang@ee.knu.ac.kr [School of Electronics Engineering, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Shon, Chae-Hwa [Korea Electrotechnology Research Institute, Changwon 642-120 (Korea, Republic of); Lee, Se-Hee, E-mail: shlees@knu.ac.kr [Department of Electrical Engineering, Kyungpook National University, Daegu 702-701 (Korea, Republic of)

    2015-05-07

    A variable inductor with magnetorheological (MR) fluid has been successfully applied to power electronics applications; however, its thermal characteristics have not been investigated. To evaluate the performance of the variable inductor with respect to temperature, we measured the characteristics of temperature rise and developed a numerical analysis technique. The characteristics of temperature rise were determined experimentally and verified numerically by adopting a multiphysics analysis technique. In order to accurately estimate the temperature distribution in a variable inductor with an MR fluid-gap, the thermal solver should import the heat source from the electromagnetic solver to solve the eddy current problem. To improve accuracy, the B–H curves of the MR fluid under operating temperature were obtained using the magnetic property measurement system. In addition, the Steinmetz equation was applied to evaluate the core loss in a ferrite core. The predicted temperature rise for a variable inductor showed good agreement with the experimental data and the developed numerical technique can be employed to design a variable inductor with a high-frequency pulsed voltage source.

  20. Design and optimization of a modular setup for measurements of three-dimensional spin polarization with ultrafast pulsed sources

    Energy Technology Data Exchange (ETDEWEB)

    Pincelli, T., E-mail: pincelli@iom.cnr.it; Rossi, G. [Dipartimento di Fisica, Università degli studi di Milano, Via Celoria 16, 20133 Milano (Italy); Laboratorio TASC, IOM-CNR, S.S. 14 km 163.5, Basovizza, 34149 Trieste (Italy); Petrov, V. N. [Saint Petersburg State Polytechnical University, Politechnicheskaya Street 29, 195251 Saint Petersburg (Russian Federation); Brajnik, G.; Carrato, S. [Università degli Studi di Trieste, Piazzale Europa 1, 34127 Trieste (Italy); Ciprian, R.; Torelli, P.; Krizmancic, D.; Salvador, F.; De Luisa, A.; Panaccione, G. [Laboratorio TASC, IOM-CNR, S.S. 14 km 163.5, Basovizza, 34149 Trieste (Italy); Lollobrigida, V. [Dipartimento di Matematica e Fisica, Università Roma Tre, I-00146 Rome (Italy); Sergo, R.; Gubertini, A.; Cautero, G. [Sincrotrone Trieste S.C.p.A, Strada Statale 14-km 163.5 in AREA Science Park, Basovizza, 34149 Trieste (Italy)

    2016-03-15

    ULTRASPIN is an apparatus devoted to the measurement of the spin polarization (SP) of electrons ejected from solid surfaces in a UHV environment. It is designed to exploit ultrafast light sources (free electron laser or laser high harmonic generation) and to perform (photo)electron spin analysis by an arrangement of Mott scattering polarimeters that measure the full SP vector. The system consists of two interconnected UHV vessels: one for surface science sample cleaning treatments, e-beam deposition of ultrathin films, and low energy electron diffraction/AES characterization. The sample environment in the polarimeter allows for cryogenic cooling and in-operando application of electric and magnetic fields. The photoelectrons are collected by an electrostatic accelerator and transport lens that form a periaxial beam that is subsequently directed by a Y-shaped electrostatic deflector to either one of the two orthogonal Mott polarimeters. The apparatus has been designed to operate in the extreme conditions of ultraintense single-X-ray pulses as originated by free electron lasers (up to 1 kHz), but it allows also for the single electron counting mode suitable when using statistical sources such as synchrotron radiation, cw-laser, or e-gun beams (up to 150 kcps).

  1. Demonstration of long-pulse acceleration of high power positive ion beam with JT-60 positive ion source in Japan–Korea joint experiment

    Energy Technology Data Exchange (ETDEWEB)

    Kojima, A., E-mail: kojima.atsushi@jaea.go.jp [Japan Atomic Energy Agency, Naka (Japan); Hanada, M. [Japan Atomic Energy Agency, Naka (Japan); Jeong, S.H. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Bae, Y.S. [National Fusion Research Institute, Daejeon (Korea, Republic of); Chang, D.H.; Kim, T.S.; Lee, K.W.; Park, M.; Jung, B.K. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Mogaki, K.; Komata, M.; Dairaku, M.; Kashiwagi, M.; Tobari, H.; Watanabe, K. [Japan Atomic Energy Agency, Naka (Japan)

    2016-01-15

    The long-pulse acceleration of the high-power positive ion beam has been demonstrated with the JT-60 positive ion source in the joint experiment among Japan Atomic Energy Agency (JAEA), Korea Atomic Energy Research Institute (KAERI) and National Fusion Research Institute (NFRI) under the collaboration program for the development of plasma heating and current drive systems. In this joint experiment, the increase of the heat load and the breakdowns induced by the degradation of the beam optics due to the gas accumulation was one of the critical issues for the long-pulse acceleration. As a result of development of the long-pulse operation techniques of the ion source and facilities of the neutral beam test stand in KAERI, 2 MW 100 s beam has been achieved for the first time. The achieved beam performance satisfies the JT-60SA requirement which is designed to be a 1.94 MW ion beam power from an ion source corresponding to total neutral beam power of 20 MW with 24 ion sources. Therefore, it was found that the JT-60 positive ion sources were applicable in the JT-60SA neutral beam injectors. Moreover, because this ion source is planned to be a backup ion source for KSTAR, the operational region and characteristic has been clarified to apply to the KSTAR neutral beam injector.

  2. Developing a Hydrologic Monitoring Network in Data-Scarce Regions Using Open-Source Arduino Dataloggers

    Directory of Open Access Journals (Sweden)

    Silja V. Hund

    2016-04-01

    Full Text Available Continuous hydrologic monitoring is limited in many regions of the world, creating serious knowledge gaps for water resources managers and scientists. Recent advances in open-source software and hardware technologies, such as the Arduino project, show potential for the development of low-cost (∼$100 automated dataloggers required for continuous data collection. We developed an Arduino-based datalogger (the Ecohydro Logger coupled with water sensors providing digital output to establish a hydrologic monitoring network in the data-scarce wet-dry tropics of Guanacaste, Costa Rica. While we experienced some challenges with a first iteration of our Arduino-based datalogger, an improved version was robust and able to capture long periods of high-frequency stream discharge data. Integration of the monitoring program into the local community was also key to successful deployment, allowing exchange of local knowledge and support. The accessible and low-cost nature of Arduino-based dataloggers can provide a means to extend continuous environmental monitoring into data-scarce regions.

  3. Operational Forest Monitoring in Siberia Using Multi-source Earth Observation Data

    Directory of Open Access Journals (Sweden)

    C. Hüttich

    2014-08-01

    Full Text Available Forest cover disturbance rates are increasing in the forests of Siberia due to intensification of human activities and climate change. In this paper two satellite data sources were used for automated forest cover change detection. Annual ALOS PALSAR backscatter mosaics (2007–2010 were used for yearly forest loss monitoring. Time series of the Enhanced Vegetation Index (EVI, 2000–2014 from the Moderate Resolution Imaging Spectroradiometer (MODIS were integrated in a web-based data middleware system to assess the capabilities of a near-real time detection of forest disturbances using the break point detection by additive season and trends (Bfast method. The SAR-based average accuracy of the forest loss detection was 70 %, whereas the MODIS-based change assessment using breakpoint detection achieved average accuracies of 50 % for trend-based breakpoints and 43.4 % for season-based breakpoints. It was demonstrated that SAR remote sensing is a highly accurate tool for up-to-date forest monitoring. Web-based data middleware systems like the Earth Observation Monitor, linked with MODIS time series, provide access and easy-to-use tools for on demand change monitoring in remote Siberian forests.

  4. The source of monoenergetic electrons for the monitoring of spectrometer in the KATRIN neutrino experiment

    CERN Document Server

    Slezák, Martin

    The international project KATRIN (KArlsruhe TRItium Neutrino experiment) is a next-generation tritium $\\beta$-decay experiment. It is designed to measure the electron anti-neutrino mass by means of a unique electron spectrometer with sensitivity of 0.2 eV/c$^2$. This is an improvement of one order of magnitude over the last results. Important part of the measurement will rest in continuous precise monitoring of high voltage of the KATRIN main spectrometer. The monitoring will be done by means of conversion electrons emitted from a solid source based on $^{83}$Rb decay. Properties of several of these sources are studied in this thesis by means of the semiconductor $\\gamma$-ray spectroscopy. Firstly, measurement of precise energy of the 9.4 keV nuclear transition observed in $^{83}$Rb decay, from which the energy of conversion electrons is derived, is reported. Secondly, measurement of activity distribution of the solid sources by means of the Timepix detector is described. Finally, a report on measurement of r...

  5. Is the Compact Source at the Center of Cas A Pulsed?

    CERN Document Server

    Murray, S S; Juda, M; Hwang, U; Holt, S S; Murray, Stephen S.; Ransom, Scott M.; Juda, Michael; Hwang, Una; Holt, Stephen S.

    2001-01-01

    A 50 ksec observation of the Supernova Remnant Cas A was taken using the Chandra X-Ray Observatory High Resolution Camera (HRC) to search for periodic signals from the compact source located near the center. Using the HRC-S in imaging mode, problems with correctly assigning times to events were overcome, allowing the period search to be extended to higher frequencies than possible with previous observations. In an extensive analysis of the HRC data, several possible candidate signals are found using various algorithms, including advanced techniques developed by Ransom to search for low significance periodic signals. Of the candidate periods, none is at a high enough confidence level to be particularly favored over the rest. When combined with other information, however (e.g., spectra, total energetics, and the historical age of the remnant), a 12 ms candidate period seems to be more physically plausible than the others, and we use it for illustrative purposes in discussing the possible properties of a putativ...

  6. Characteristics of cold atmospheric plasma source based on low-current pulsed discharge with coaxial electrodes

    Science.gov (United States)

    Bureyev, O. A.; Surkov, Yu S.; Spirina, A. V.

    2017-05-01

    This work investigates the characteristics of the gas discharge system used to create an atmospheric pressure plasma flow. The plasma jet design with a cylindrical graphite cathode and an anode rod located on the axis of the system allows to realize regularly reproducible spark breakdowns mode with a frequency ∼ 5 kHz and a duration ∼ 40 μs. The device generates a cold atmospheric plasma flame with 1 cm in diameter in the flow of various plasma forming gases including nitrogen and air at about 100 mA average discharge current. In the described construction the cathode spots of individual spark channels randomly move along the inner surface of the graphite electrode creating the secondary plasma stream time-average distributed throughout the whole exit aperture area after the decay of numerous filamentary discharge channels. The results of the spectral diagnostics of plasma in the discharge gap and in the stream coming out of the source are presented. Despite the low temperature of atoms and molecules in plasma stream the cathode spots operation with temperature of ∼ 4000 °C at a graphite electrode inside a discharge system enables to saturate the plasma by CN-radicals and atomic carbon in the case of using nitrogen as the working gas.

  7. Radiography using a dense plasma focus device as a source of pulsed X-rays

    Science.gov (United States)

    Herrera, Julio; Castillo, Fermín; Gamboa, Isabel; Rangel, José

    2007-11-01

    Soft and hard X-ray emissions have been studied in the FN-II, which is a small dense plasma focus machine (5 kJ), operating at the Instituto de Ciencias Nucleares, UNAM, using aluminum filtered pin-hole cameras. Their angular distribution has been measured using TLD-200 dosimeters [1]. Their temporal evolution has been observed by means of a PIN diode, and scinltillators coupled to photomultipliers outside the discharge chamber. The X rays source can be concentrated by placing a needle on the end of the electrode. X-rays crossing across a 300 micron aluminum window, through the axis of the machine, can be used to obtain high contrast radiographs, with an average dose of 0.4 mGy per shot. In contrast, the average dose with a hollow cathode is 0.2 mGy per shot. This work is partially supported by grant IN105705 de la DGAPA-UNAM. [1] F. Castillo, J.J.E. Herrera, J. Rangel, I. Gamboa, G. Espinosa y J.I. Golzarri ``Angular Distribution of fusion products and X-rays emitted by a small dense plasma focus machine'' Journal of Applied Physics 101 013303-1-7 (2007).

  8. 10-GHz return-to-zero pulse source tunable in wavelength with a single- or multiwavelength output based on four-wave mixing in a newly developed highly nonlinear fiber

    DEFF Research Database (Denmark)

    Clausen, A. T.; Oxenlowe, L.; Peucheret, Christophe;

    2001-01-01

    In this letter, a novel scheme for a wavelength-tunable pulse source (WTPS) is proposed and characterized. It is based on four-wave mixing (FWM) in a newly developed highly nonlinear fiber between a return-to-zero (RZ) pulsed signal at a fixed wavelength and a continuous wave probe tunable...... the WTPS compared to the original RZ pulses is negligible....

  9. Stable carbon isotopes to monitor the CO2 source mix in the urban environment

    Science.gov (United States)

    Vogel, F. R.; Wu, L.; Ramonet, M.; Broquet, G.; Worthy, D. E. J.

    2014-12-01

    Urban areas are said to be responsible for approximately 71% of fossil fuel CO2 emissions while comprising only two percent of the land area [IEA, 2008]. This limited spatial expansion could facility a monitoring of anthropogenic GHGs from atmospheric observations. As major sources of emissions, cities also have a huge potential to drive emissions reductions. To effectively manage emissions, cities must however, first establish techniques to validate their reported emission statistics. A pilot study which includes continues 13CO2 data from calibrated cavity ring-down spectrometers [Vogel et al. 2013] of two "sister sites" in the vicinity of Toronto, Canada is contrasted to recent observations of 13CO2 observations in Paris during significant pollution events. Using Miller-Tans plots [Miller and Tans, 2003] for our multi-season observations reveals significant changes of the source signatures of night time CO2 emissions which reflect the importance of natural gas burning in Megacities (up to 80% of fossil fuel sources) and show-case the potential of future isotope studies to determine source sectors. Especially the winter data this approach seems suitable to determine the source contribution of different fuel types (natural gas, liquid fuels and coal) which can inform the interpretation of other Greenhouse Gases and air pollution levels.

  10. Transverse Beam Halo Measurements at High Intensity Neutrino Source (HINS) using Vibrating Wire Monitor

    Energy Technology Data Exchange (ETDEWEB)

    Chung, M.; Hanna, B.; Scarpine, V.; Shiltsev, V.; Steimel, J.; Artinian, S.; Arutunian, S.

    2015-02-26

    The measurement and control of beam halos will be critical for the applications of future high-intensity hadron linacs. In particular, beam profile monitors require a very high dynamic range when used for the transverse beam halo measurements. In this study, the Vibrating Wire Monitor (VWM) with aperture 60 mm was installed at the High Intensity Neutrino Source (HINS) front-end to measure the transverse beam halo. A vibrating wire is excited at its resonance frequency with the help of a magnetic feedback loop, and the vibrating and sensitive wires are connected through a balanced arm. The sensitive wire is moved into the beam halo region by a stepper motor controlled translational stage. We study the feasibility of the vibrating wire for the transverse beam halo measurements in the low-energy front-end of the proton linac.

  11. Monitoring of atmospheric nitrogen dioxide by long-path pulsed differential optical absorption spectroscopy using two different light paths.

    Science.gov (United States)

    Kambe, Yasuaki; Yoshii, Yotsumi; Takahashi, Kenshi; Tonokura, Kenichi

    2012-03-01

    Measurements of the local distribution of atmospheric nitrogen dioxide (NO(2)) by long-path pulsed differential optical absorption spectroscopy (LP-PDOAS) in Tokyo during August 2008 are presented. Two LP-PDOAS systems simultaneously measured average NO(2) temporal mixing ratios along two different paths from a single observation point. Two flashing aviation obstruction lights, located 7.0 km north and 6.3 km east from the observation point, were used as light sources, allowing spatiotemporal variations of NO(2) in Tokyo to be inferred. The LP-PDOAS data were compared with ground-based data measured using chemiluminescence. Surface wind data indicated that large inhomogeneities were present in the spatial NO(2) distributions under southerly wind conditions, while northerly wind conditions displayed greater homogeneity between the two systems. The higher correlation in the NO(2) mixing ratio between the two LP-PDOAS systems was observed under northerly wind conditions with a correlation factor R(2) = 0.88. We demonstrated that the combined deployment of two LP-PDOAS systems oriented in different directions provides detailed information on the spatial distribution of NO(2).

  12. 基于TTL数字电路控制的高压脉冲源%High-voltage pulse source controlled by TTL digital circuit

    Institute of Scientific and Technical Information of China (English)

    李玺钦; 丁明军; 吴红光; 冯莉; 刘云涛; 戴文峰; 黄雷

    2012-01-01

    给出了一种基于TTL数字电路作为高压脉冲源触发控制单元的设计原理和方法.介绍了高压脉冲源的工作原理,设计了一台脉冲输出幅度5 kV、脉冲宽度大于200 μs及脉冲前沿小于30 ns的高压脉冲源.将触发控制单元和前级开关金属氧化物半导体场效应管(MOSFET)组合成一体,控制后级气体高压开关管放电输出高压脉冲信号.实验结果验证了所采用的设计原理及方法的可行性,给出了单次触发情况下的实验结果.%The paper introduces a TTL digital circuit, which is designed as the trigger control system of high power pulse source, and presents the development of a high-voltage pulse source. In the source, the TTL circuit operated after the optical isolation circuit and power driver, and outputs pulse signals to drive MOSFET, which controls the pulse signal output from high-voltage switch. The source can outputs pulses with voltage of 5 kV, pulse-width larger than 200 Ωs and fall-time less than 30 ns. Besides long-distance control and local control mode, it also includes inner trigger and external trigger (one electric signal and one optical signal as the trigger). A series of experiments have been conducted to validate the design, and the one-shot trigger results are presented.

  13. New Advanced Source Identification Algorithm (ASIA-NEW) for radiation monitors with plastic detectors

    Energy Technology Data Exchange (ETDEWEB)

    Stavrov, Andrei; Yamamoto, Eugene [Rapiscan Systems, Inc., 14000 Mead Street, Longmont, CO, 80504 (United States)

    2015-07-01

    Radiation Portal Monitors (RPM) with plastic detectors represent the main instruments used for primary border (customs) radiation control. RPM are widely used because they are simple, reliable, relatively inexpensive and have a high sensitivity. However, experience using the RPM in various countries has revealed the systems have some grave shortcomings. There is a dramatic decrease of the probability of detection of radioactive sources under high suppression of the natural gamma background (radiation control of heavy cargoes, containers and, especially, trains). NORM (Naturally Occurring Radioactive Material) existing in objects under control trigger the so-called 'nuisance alarms', requiring a secondary inspection for source verification. At a number of sites, the rate of such alarms is so high it significantly complicates the work of customs and border officers. This paper presents a brief description of new variant of algorithm ASIA-New (New Advanced Source Identification Algorithm), which was developed by the authors and based on some experimental test results. It also demonstrates results of different tests and the capability of a new system to overcome the shortcomings stated above. New electronics and ASIA-New enables RPM to detect radioactive sources under a high background suppression (tested at 15-30%) and to verify the detected NORM (KCl) and the artificial isotopes (Co-57, Ba-133 and other). New variant of ASIA is based on physical principles and does not require a lot of special tests to attain statistical data for its parameters. That is why this system can be easily installed into any RPM with plastic detectors. This algorithm was tested for 1,395 passages of different transports (cars, trucks and trailers) without radioactive sources. It also was tested for 4,015 passages of these transports with radioactive sources of different activity (Co-57, Ba-133, Cs-137, Co-60, Ra-226, Th-232) and these sources masked by NORM (K-40) as well

  14. Wearable Sensor Localization Considering Mixed Distributed Sources in Health Monitoring Systems.

    Science.gov (United States)

    Wan, Liangtian; Han, Guangjie; Wang, Hao; Shu, Lei; Feng, Nanxing; Peng, Bao

    2016-03-12

    In health monitoring systems, the base station (BS) and the wearable sensors communicate with each other to construct a virtual multiple input and multiple output (VMIMO) system. In real applications, the signal that the BS received is a distributed source because of the scattering, reflection, diffraction and refraction in the propagation path. In this paper, a 2D direction-of-arrival (DOA) estimation algorithm for incoherently-distributed (ID) and coherently-distributed (CD) sources is proposed based on multiple VMIMO systems. ID and CD sources are separated through the second-order blind identification (SOBI) algorithm. The traditional estimating signal parameters via the rotational invariance technique (ESPRIT)-based algorithm is valid only for one-dimensional (1D) DOA estimation for the ID source. By constructing the signal subspace, two rotational invariant relationships are constructed. Then, we extend the ESPRIT to estimate 2D DOAs for ID sources. For DOA estimation of CD sources, two rational invariance relationships are constructed based on the application of generalized steering vectors (GSVs). Then, the ESPRIT-based algorithm is used for estimating the eigenvalues of two rational invariance matrices, which contain the angular parameters. The expressions of azimuth and elevation for ID and CD sources have closed forms, which means that the spectrum peak searching is avoided. Therefore, compared to the traditional 2D DOA estimation algorithms, the proposed algorithm imposes significantly low computational complexity. The intersecting point of two rays, which come from two different directions measured by two uniform rectangle arrays (URA), can be regarded as the location of the biosensor (wearable sensor). Three BSs adopting the smart antenna (SA) technique cooperate with each other to locate the wearable sensors using the angulation positioning method. Simulation results demonstrate the effectiveness of the proposed algorithm.

  15. Wearable Sensor Localization Considering Mixed Distributed Sources in Health Monitoring Systems

    Directory of Open Access Journals (Sweden)

    Liangtian Wan

    2016-03-01

    Full Text Available In health monitoring systems, the base station (BS and the wearable sensors communicate with each other to construct a virtual multiple input and multiple output (VMIMO system. In real applications, the signal that the BS received is a distributed source because of the scattering, reflection, diffraction and refraction in the propagation path. In this paper, a 2D direction-of-arrival (DOA estimation algorithm for incoherently-distributed (ID and coherently-distributed (CD sources is proposed based on multiple VMIMO systems. ID and CD sources are separated through the second-order blind identification (SOBI algorithm. The traditional estimating signal parameters via the rotational invariance technique (ESPRIT-based algorithm is valid only for one-dimensional (1D DOA estimation for the ID source. By constructing the signal subspace, two rotational invariant relationships are constructed. Then, we extend the ESPRIT to estimate 2D DOAs for ID sources. For DOA estimation of CD sources, two rational invariance relationships are constructed based on the application of generalized steering vectors (GSVs. Then, the ESPRIT-based algorithm is used for estimating the eigenvalues of two rational invariance matrices, which contain the angular parameters. The expressions of azimuth and elevation for ID and CD sources have closed forms, which means that the spectrum peak searching is avoided. Therefore, compared to the traditional 2D DOA estimation algorithms, the proposed algorithm imposes significantly low computational complexity. The intersecting point of two rays, which come from two different directions measured by two uniform rectangle arrays (URA, can be regarded as the location of the biosensor (wearable sensor. Three BSs adopting the smart antenna (SA technique cooperate with each other to locate the wearable sensors using the angulation positioning method. Simulation results demonstrate the effectiveness of the proposed algorithm.

  16. A PC-Based Pulse Oximetry Monitor for Four Patients%微机化多床位脉搏血氧饱和度监测仪

    Institute of Scientific and Technical Information of China (English)

    刘国忠; 李萍

    2001-01-01

    微机多床位脉搏血氧饱和度监测仪具有系统结构简单、灵活、存储容量大、功能强、性能价格比高等特点,且易实现多机通讯。介绍了监测仪的硬件系统组成原理及软件模块功能。%Pulse oximeters are used in many departments of a hospital. The pc-based pulse oximetry monitor for many patients has the features of simplicity, flexbility, large memory,powerful function, high ratio of performance to price, and it is easy to communicate with mul-timonitors. The principles of hardware system and the function of software block of the monitor are introduced too in this paper.

  17. Cross-validation of theoretically quantified fiber continuum generation and absolute pulse measurement by MIIPS for a broadband coherently controlled optical source

    DEFF Research Database (Denmark)

    Tu, H.; Liu, Y.; Lægsgaard, Jesper

    2012-01-01

    The predicted spectral phase of a fiber continuum pulsed source rigorously quantified by the scalar generalized nonlinear Schrödinger equation is found to be in excellent agreement with that measured by multiphoton intrapulse interference phase scan (MIIPS) with background subtraction. This cross...

  18. RadSTraM: Radiological Source Tracking and Monitoring, Phase II Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Warren, Tracy A [ORNL; Walker, Randy M [ORNL; Hill, David E [ORNL; Gross, Ian G [ORNL; Smith, Cyrus M [ORNL; Abercrombie, Robert K [ORNL

    2008-12-01

    This report focuses on the technical information gained from the Radiological Source Tracking and Monitoring (RadSTraM) Phase II investigation and its implications. The intent of the RadSTraM project was to determine the feasibility of tracking radioactive materials in commerce, particularly International Atomic Energy Agency (IAEA) Category 3 and 4 materials. Specifically, Phase II of the project addressed tracking radiological medical isotopes in commerce. These categories of materials are susceptible to loss or theft but the problem is not being addressed by other agencies.

  19. Solar wind Alfvén waves: a source of pulsed ionospheric convection and atmospheric gravity waves

    Directory of Open Access Journals (Sweden)

    P. Prikryl

    2005-02-01

    Full Text Available A case study of medium-scale travelling ionospheric disturbances (TIDs that are correlated with solar wind Alfvén waves is presented. The HF radar ground-scatter signatures of TIDs caused by atmospheric gravity waves with periods of 20-40min are traced to a source at high latitudes, namely pulsed ionospheric flows (PIFs due to bursts in the convection electric field and/or the associated ionospheric current fluctuations inferred from ground magnetic field perturbations. The significance of PIFs and TIDs in the context of solar-terrestrial interaction is that Alfvénic fluctuations of the interplanetary magnetic field (IMF observed in the solar wind plasma streaming from a coronal hole correlate with PIFs and TIDs. The link between the solar wind Alfvén waves and TIDs is corroborated by the ground magnetic field signatures of ionospheric current fluctuations that are associated with the IMF-By oscillations and TIDs. The observed PIFs and the associated negative-to-positive deflections of the ground magnetic field X component are interpreted as ionospheric signatures of magnetic reconnection pulsed by solar wind Alfvén waves at the dayside magnetopause. Although the clarity of the radar line-of-sight velocity data may have been affected by anomalous HF propagation due to intervening TIDs, the application of a pure state filtering technique to analyze the radar data time series reveals a one-to-one correspondence between PIFs, TIDs and solar wind Alfvén waves. The spectra of solar wind and ground magnetic field perturbations are similar to those of PIFs and TIDs. The ground-scatter signatures indicate TID wavelengths, phase velocities and travel times that are consistent with ray tracing, which shows a subset of possible gravity wave group paths that reach the F region from a source in the E region after the wave energy first travel downward to the upper mesosphere where the waves are reflected upward. The observed one

  20. Whose idea was that? Source monitoring for idea ownership following elaboration.

    Science.gov (United States)

    Stark, Louisa-Jayne; Perfect, Timothy J

    2007-10-01

    Unconscious plagiarism (UP) occurs when an individual claims a previously experienced idea as their own. Previous studies have explored the cognitive precursors of such errors by manipulating the ways that ideas are thought about between initial idea exposure and later test. While imagining other's ideas does not increase rates of UP relative to control on either a recall-own or generate-new task, improving others' ideas substantially increases such errors in the recall-own task. This study explored the effects of elaboration on rates of UP when a source-monitoring test replaced the recall-own test. Plagiarism was again observed following idea improvement but not idea imagery even though participants engaged explicit source evaluation. Thus the probability of plagiarising another's idea appears linked to the generative nature of the idea processing performed.

  1. Analysis of seismic sources for different mechanisms of fracture growth for microseismic monitoring applications

    Energy Technology Data Exchange (ETDEWEB)

    Duchkov, A. A., E-mail: DuchkovAA@ipgg.sbras.ru [Trofimuk Institute of Petroleum Geology and Geophysics SB RAS, Novosibirsk, 630090 (Russian Federation); Novosibirsk State University, Novosibirsk, 630090 (Russian Federation); Stefanov, Yu. P., E-mail: stefanov@ispms.tsc.ru [Trofimuk Institute of Petroleum Geology and Geophysics SB RAS, Novosibirsk, 630090 (Russian Federation)

    2015-10-27

    We have developed and illustrated an approach for geomechanic modeling of elastic wave generation (microsiesmic event occurrence) during incremental fracture growth. We then derived properties of effective point seismic sources (radiation patterns) approximating obtained wavefields. These results establish connection between geomechanic models of hydraulic fracturing and microseismic monitoring. Thus, the results of the moment tensor inversion of microseismic data can be related to different geomechanic scenarios of hydraulic fracture growth. In future, the results can be used for calibrating hydrofrac models. We carried out a series of numerical simulations and made some observations about wave generation during fracture growth. In particular when the growing fracture hits pre-existing crack then it generates much stronger microseismic event compared to fracture growth in homogeneous medium (radiation pattern is very close to the theoretical dipole-type source mechanism)

  2. Monitoring physical properties of a submarine groundwater discharge source at Kalogria Bay, SW Peloponnissos, Greece

    Science.gov (United States)

    Karageorgis, A. P.; Papadopoulos, V. P.; Georgopoulos, D.; Kanellopoulos, Th. D.; Papathanassiou, E.

    2012-04-01

    An impressive SGD in Kalogria Bay (SW Peloponnissos) was surveyed for the first time in 2006, revealing the existence of 2 major and 2 minor point sources of freshwater (salinity ~l-2); the discharge was ~ 1000 m3 h-1. The major point source was located in a karstic cavity at 25 m depth. In July 2009, and for a period of one year, the site was monitored intensively. During summer, the underwater discharge was not very strong, the water was flowing from many dispersed points, and salinity range was 20-36. During autumn and winter, flow velocity increased considerably (> 1 m s-1), and the SGDs discharged water of low salinity (< 2). Gradually, the smaller SGDs ceased their operation, and the major SGD emanated brackish water during spring and summer, thus hampering the possibilities of freshwater exploitation, in a touristic area which suffers from great aridity and water demand is high during summer.

  3. Monitoring physical properties of a submarine groundwater discharge source at Kalogria Bay, SW Peloponnissos, Greece

    Directory of Open Access Journals (Sweden)

    Papathanassiou E.

    2012-04-01

    Full Text Available An impressive SGD in Kalogria Bay (SW Peloponnissos was surveyed for the first time in 2006, revealing the existence of 2 major and 2 minor point sources of freshwater (salinity ~l-2; the discharge was ~ 1000 m3 h−1. The major point source was located in a karstic cavity at 25 m depth. In July 2009, and for a period of one year, the site was monitored intensively. During summer, the underwater discharge was not very strong, the water was flowing from many dispersed points, and salinity range was 20–36. During autumn and winter, flow velocity increased considerably (> 1 m s−1, and the SGDs discharged water of low salinity (< 2. Gradually, the smaller SGDs ceased their operation, and the major SGD emanated brackish water during spring and summer, thus hampering the possibilities of freshwater exploitation, in a touristic area which suffers from great aridity and water demand is high during summer.

  4. Investigating the value of passive microwave observations for monitoring volcanic eruption source parameters

    Science.gov (United States)

    Montopoli, Mario; Cimini, Domenico; Marzano, Frank

    2016-04-01

    Volcanic eruptions inject both gas and solid particles into the Atmosphere. Solid particles are made by mineral fragments of different sizes (from few microns to meters), generally referred as tephra. Tephra from volcanic eruptions has enormous impacts on social and economical activities through the effects on the environment, climate, public health, and air traffic. The size, density and shape of a particle determine its fall velocity and thus residence time in the Atmosphere. Larger particles tend to fall quickly in the proximity of the volcano, while smaller particles may remain suspended for several days and thus may be transported by winds for thousands of km. Thus, the impact of such hazards involves local as well as large scales effects. Local effects involve mostly the large sized particles, while large scale effects are caused by the transport of the finest ejected tephra (ash) through the atmosphere. Forecasts of ash paths in the atmosphere are routinely run after eruptions using dispersion models. These models make use of meteorological and volcanic source parameters. The former are usually available as output of numerical weather prediction models or large scale reanalysis. Source parameters characterize the volcanic eruption near the vent; these are mainly the ash mass concentration along the vertical column and the top altitude of the volcanic plume, which is strictly related to the flux of the mass ejected at the emission source. These parameters should be known accurately and continuously; otherwise, strong hypothesis are usually needed, leading to large uncertainty in the dispersion forecasts. However, direct observations during an eruption are typically dangerous and impractical. Thus, satellite remote sensing is often exploited to monitor volcanic emissions, using visible (VIS) and infrared (IR) channels available on both Low Earth Orbit (LEO) and Geostationary Earth Orbit (GEO) satellites. VIS and IR satellite imagery are very useful to monitor

  5. Pulse Arrival Time Based Cuff-Less and 24-H Wearable Blood Pressure Monitoring and its Diagnostic Value in Hypertension.

    Science.gov (United States)

    Zheng, Yali; Poon, Carmen C Y; Yan, Bryan P; Lau, James Y W

    2016-09-01

    Ambulatory blood pressure monitoring (ABPM) has become an essential tool in the diagnosis and management of hypertension. Current standard ABPM devices use an oscillometric cuff-based method which can cause physical discomfort to the patients with repeated inflations and deflations, especially during nighttime leading to sleep disturbance. The ability to measure ambulatory BP accurately and comfortably without a cuff would be attractive. This study validated the accuracy of a cuff-less approach for ABPM using pulse arrival time (PAT) measurements on both healthy and hypertensive subjects for potential use in hypertensive management, which is the first of its kind. The wearable cuff-less device was evaluated against a standard cuff-based device on 24 subjects of which 15 have known hypertension. BP measurements were taken from each subject over a 24-h period by the cuff-less and cuff-based devices every 15 to 30 minutes during daily activities. Mean BP of each subject during daytime, nighttime and over 24-h were calculated. Agreement between mean nighttime systolic BP (SBP) and diastolic (DBP) measured by the two devices evaluated using Bland-Altman plot were -1.4 ± 6.6 and 0.4 ± 6.7 mmHg, respectively. Receiver operator characteristics (ROC) statistics was used to assess the diagnostic accuracy of the cuff-less approach in the detection of BP above the hypertension threshold during nighttime (>120/70 mmHg). The area under ROC curves were 0.975/0.79 for nighttime. The results suggest that PAT-based approach is accurate and promising for ABPM without the issue of sleep disturbances associated with cuff-based devices.

  6. High-frequency nutrient monitoring to infer seasonal patterns in catchment source availability, mobilisation and delivery.

    Science.gov (United States)

    Bende-Michl, Ulrike; Verburg, Kirsten; Cresswell, Hamish P

    2013-11-01

    To explore the value of high-frequency monitoring to characterise and explain riverine nutrient concentration dynamics, total phosphorus (TP), reactive phosphorus (RP), ammonium (NH4-N) and nitrate (NO3-N) concentrations were measured hourly over a 2-year period in the Duck River, in north-western Tasmania, Australia, draining a 369-km(2) mixed land use catchment area. River discharge was observed at the same location and frequency, spanning a wide range of hydrological conditions. Nutrient concentrations changed rapidly and were higher than previously observed. Maximum nutrient concentrations were 2,577 μg L(-1) TP, 1,572 μg L(-1) RP, 972 μg L(-1) NH₄-N and 1,983 μg L(-1) NO₃-N, respectively. Different nutrient response patterns were evident at seasonal, individual event and diurnal time scales-patterns that had gone largely undetected in previous less frequent water quality sampling. Interpretation of these patterns in terms of nutrient source availability, mobilisation and delivery to the stream allowed the development of a conceptual model of catchment nutrient dynamics. Functional stages of nutrient release were identified for the Duck River catchment and were supported by a cluster analysis which confirmed the similarities and differences in nutrient responses caused by the sequence of hydrologic events: (1) a build-up of nutrients during periods with low hydrologic activity, (2) flushing of readily available nutrient sources at the onset of the high flow period, followed by (3) a switch from transport to supply limitation, (4) the accessibility of new nutrient sources with increasing catchment wetness and hydrologic connectivity and (5) high nutrient spikes occurring when new sources become available that are easily mobilised with quickly re-established hydrologic connectivity. Diurnal variations that could be influenced by riverine processes and/or localised point sources were also identified as part of stage (1) and during late recession of some of

  7. Multi-Scale Monitoring and Assessment of Nonpoint Source Pollution in Groundwater

    Science.gov (United States)

    Harter, T.; Vanderschans, M.; Leijnse, A.; Mathews, M. C.; Meyer, R. D.

    2003-04-01

    The California dairy industry produces 20% of US milk and is the largest animal industry in the state. Many of the dairy facilities are located in low-relief valleys and basins with vulnerable groundwater resources. The continued influx of dairies into California's Central Valley has raised critical questions regarding their environmental performance, in particular with respect to groundwater quality impacts. While animal farming systems are considered among the leading sources of groundwater nitrate,little is known about the actual impact of dairy farming practices on groundwater quality in the extensive alluvial aquifers underlying the Central Valley. With our work we attempt to characterize and assess shallow groundwater underneath dairies in a relatively vulnerable hydrogeologic region and to discern the impact from various individual sources and management practices within dairies. An extensive shallow groundwater monitoring network was installed on five representative dairy operations in the northeastern San Joaquin Valley, California. The monitoring network spans all dairy management units: manure water lagoons, corrals, storage areas, and manure treated forage fields under various management practices. We recently also surveyed production well water quality. Water quality is found to be highly variable, both in time and space. We propose that a meaningful interpretation of these (nonpoint source pollution) data is only possible by explicitly considering the various scales affiliated with groundwater measurement, pollution source management, regulatory control, and beneficial use. Using statistical analysis and innovative modeling tools, we provide an interpretation of the observed data that is meaningful at the field scale (the scale unit of management decisions), the farm scale (considered to be a regulatory and planning unit), and the regional scale (considered to be a planning unit).

  8. PRELIMINARY STUDY OF COMBINED PULSED VACUUM ARC SOURCE PLASMA%组合体脉冲真空电弧源的初步研究

    Institute of Scientific and Technical Information of China (English)

    李璟; 黄杰; 王锴; 张荟星; 彭建华; 邓春凤; 吴先映

    2014-01-01

    为得到高密度的等离子体,设计研制了组合体脉冲真空电弧源,它由4套脉冲真空电弧源组合而成.测量了脉冲真空电弧源弧压与弧流的关系;利用静电探针测量了组合体脉冲真空电弧源和单套脉冲真空电弧源产生的等离子体,得到了探针饱和电流(与等离子体密度成正比)与弧压的关系,以及等离子体密度的轴向分布情况;采用飞行时间方法估测了等离子体的飞行速度.组合脉冲真空电弧源最大等离子体密度达到8×1012 cm-3.%In order to get high density plasma,a combined pulsed vacuum arc source is designed and developed with four pulsed vacuum arc sources.The relationship of arc voltage and arc current is measured;The plasma in combined pulsed vacuum arc source and single pulsed vacuum arc source are measured using electrical probe.The relationship of probe saturation current (in proportion to plasma density)versus arc voltage and axial distribution of plasma are measured;The plasma velocity is estimated using time-of-flight method.The maximal plasma density in combined pulsed vacuum arc source is 8×1012 cm-3 .

  9. Radiative neutron capture as a counting technique at pulsed spallation neutron sources: a review of current progress

    Science.gov (United States)

    Schooneveld, E. M.; Pietropaolo, A.; Andreani, C.; Perelli Cippo, E.; Rhodes, N. J.; Senesi, R.; Tardocchi, M.; Gorini, G.

    2016-09-01

    Neutron scattering techniques are attracting an increasing interest from scientists in various research fields, ranging from physics and chemistry to biology and archaeometry. The success of these neutron scattering applications is stimulated by the development of higher performance instrumentation. The development of new techniques and concepts, including radiative capture based neutron detection, is therefore a key issue to be addressed. Radiative capture based neutron detectors utilize the emission of prompt gamma rays after neutron absorption in a suitable isotope and the detection of those gammas by a photon counter. They can be used as simple counters in the thermal region and (simultaneously) as energy selector and counters for neutrons in the eV energy region. Several years of extensive development have made eV neutron spectrometers operating in the so-called resonance detector spectrometer (RDS) configuration outperform their conventional counterparts. In fact, the VESUVIO spectrometer, a flagship instrument at ISIS serving a continuous user programme for eV inelastic neutron spectroscopy measurements, is operating in the RDS configuration since 2007. In this review, we discuss the physical mechanism underlying the RDS configuration and the development of associated instrumentation. A few successful neutron scattering experiments that utilize the radiative capture counting techniques will be presented together with the potential of this technique for thermal neutron diffraction measurements. We also outline possible improvements and future perspectives for radiative capture based neutron detectors in neutron scattering application at pulsed neutron sources.

  10. Influence of gas pressure on electron beam emission current of pulsed cathodic-arc-based forevacuum plasma electron source

    Science.gov (United States)

    Burdovitsin, Victor A.; Kazakov, Andrey V.; Medovnik, Alexander V.; Oks, Efim M.

    2017-09-01

    We describe our experimental investigation of the effect of background gas pressure on the emission parameters of a pulsed cathodic-arc-based forevacuum-pressure plasma-cathode electron source. We find that increased gas pressure over the range 4-16 Pa significantly reduces the beam current rise-time and significantly increases the emission current amplitude. For example, at a discharge current of 20 A, increasing the working gas pressure from 4 Pa to 16 Pa increases the emission current from 8 A to 18 A and shortens the beam rise-time from 50 μs to 20 μs. This influence of gas pressure on the electron beam parameters can be explained by the effect of arc discharge current switching from the anode to emission. In our case, the current switching effect is caused by increased working gas pressure. In the forevacuum pressure range, the increase of the electron emission current with the growth of gas pressure is due to a rise in the emission plasma potential which is caused by ion back-streaming from the plasma formed in the electron beam transport region. A model describing the influence of gas pressure on the electron emission from the plasma is presented.

  11. Guidelines of care for vascular lasers and intense pulse light sources from the European Society for Laser Dermatology.

    Science.gov (United States)

    Adamič, M; Pavlović, M D; Troilius Rubin, A; Palmetun-Ekbäck, M; Boixeda, P

    2015-09-01

    Lasers and non-coherent intense pulse light sources (IPLS) are based on the principle of selective photothermolysis and can be used for the treatment of many vascular skin lesions. A variety of lasers has been developed for the treatment of congenital and acquired vascular lesions which incorporate these concepts into their design. Although laser and light sources are very popular due to their non-invasive nature, caution should be considered by practitioners and patients to avoid permanent side-effects. The aim of these guidelines is to give evidence-based recommendations for the use of lasers and IPLS in the treatment of vascular lesions. These guidelines were produced by a Consensus Panel made up of experts in the field of vascular laser surgery under the auspices of the European Society of Laser Dermatology. Recommendations on the use of vascular lasers and IPLS were made based on the quality of evidence for efficacy, safety, tolerability, cosmetic outcome, patient satisfaction/preference and, where appropriate, on the experts' opinion. The recommendations of these guidelines are graded according to the American College of Chest Physicians Task Force recommendations on Grading Strength of Recommendations and Quality of Evidence in Clinical Guidelines. Lasers and IPLS are very useful and sometimes the only available method to treat various vascular lesions. It is of a paramount importance that the type of laser or IPLS and their specific parameters are adapted to the indication but also that the treating physician is familiar with the device to be used. The crucial issue in treating vascular lesions is to recognize the immediate end-point after laser treatment. This is the single most important factor to ensure both the efficacy of the treatment and avoidance of serious side-effects. © 2015 European Academy of Dermatology and Venereology.

  12. Structural Health Monitoring of Wind Turbine Blades: Acoustic Source Localization Using Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Omar Mabrok Bouzid

    2015-01-01

    Full Text Available Structural health monitoring (SHM is important for reducing the maintenance and operation cost of safety-critical components and systems in offshore wind turbines. This paper proposes an in situ wireless SHM system based on an acoustic emission (AE technique. By using this technique a number of challenges are introduced due to high sampling rate requirements, limitations in the communication bandwidth, memory space, and power resources. To overcome these challenges, this paper focused on two elements: (1 the use of an in situ wireless SHM technique in conjunction with the utilization of low sampling rates; (2 localization of acoustic sources which could emulate impact damage or audible cracks caused by different objects, such as tools, bird strikes, or strong hail, all of which represent abrupt AE events and could affect the structural health of a monitored wind turbine blade. The localization process is performed using features extracted from aliased AE signals based on a developed constraint localization model. To validate the performance of these elements, the proposed system was tested by testing the localization of the emulated AE sources acquired in the field.

  13. Pulse amplitude modulated chlorophyll fluorometer

    Energy Technology Data Exchange (ETDEWEB)

    Greenbaum, Elias; Wu, Jie

    2015-12-29

    Chlorophyll fluorometry may be used for detecting toxins in a sample because of changes in micro algae. A portable lab on a chip ("LOAC") based chlorophyll fluorometer may be used for toxin detection and environmental monitoring. In particular, the system may include a microfluidic pulse amplitude modulated ("PAM") chlorophyll fluorometer. The LOAC PAM chlorophyll fluorometer may analyze microalgae and cyanobacteria that grow naturally in source drinking water.

  14. A Low-Power and Portable Biomedical Device for Respiratory Monitoring with a Stable Power Source

    Directory of Open Access Journals (Sweden)

    Jiachen Yang

    2015-08-01

    Full Text Available Continuous respiratory monitoring is an important tool for clinical monitoring. Associated with the development of biomedical technology, it has become more and more important, especially in the measuring of gas flow and CO2 concentration, which can reflect the status of the patient. In this paper, a new type of biomedical device is presented, which uses low-power sensors with a piezoresistive silicon differential pressure sensor to measure gas flow and with a pyroelectric sensor to measure CO2 concentration simultaneously. For the portability of the biomedical device, the sensors and low-power measurement circuits are integrated together, and the airway tube also needs to be miniaturized. Circuits are designed to ensure the stability of the power source and to filter out the existing noise. Modulation technology is used to eliminate the fluctuations at the trough of the waveform of the CO2 concentration signal. Statistical analysis with the coefficient of variation was performed to find out the optimal driving voltage of the pressure transducer. Through targeted experiments, the biomedical device showed a high accuracy, with a measuring precision of 0.23 mmHg, and it worked continuously and stably, thus realizing the real-time monitoring of the status of patients.

  15. Comparative study of SVPWM (space vector pulse width modulation) & SPWM (sinusoidal pulse width modulation) based three phase voltage source inverters for variable speed drive

    Science.gov (United States)

    Ahmed, Waheed; Usman Ali, Syed M.

    2013-12-01

    We have performed comparative studies of Space Vector Pulse Width Modulation (SVPWM) and Sinusoidal Pulse Width Modulation (SPWM) techniques utilizing MATLAB tools. During these investigations, we carried out intensive simulations, comprehensively analyzed the obtained results and compared the harmonic density, power factor (PF), & switching losses of SVPWM and SPWM. It has been observed during investigations that if the switching frequency is high then losses due to harmonics are negligible, thus based on obtained results we suggested that the SVPWM technique is a more reliable solution. Because SVPWM utilizes DC bus voltage more efficiently, generates less Total Harmonic Distortion (THD) and has higher output quality it provides flexible control of output voltage and output frequency for Variable Speed Drive (VSD).

  16. Quantitative Analysis of VIIRS DNB Nightlight Point Source for Light Power Estimation and Stability Monitoring

    Directory of Open Access Journals (Sweden)

    Changyong Cao

    2014-12-01

    Full Text Available The high sensitivity and advanced onboard calibration on the Visible Infrared Imaging Radiometer Suite (VIIRS Day/Night Band (DNB enables accurate measurements of low light radiances which leads to enhanced quantitative applications at night. The finer spatial resolution of DNB also allows users to examine social economic activities at urban scales. Given the growing interest in the use of the DNB data, there is a pressing need for better understanding of the calibration stability and absolute accuracy of the DNB at low radiances. The low light calibration accuracy was previously estimated at a moderate 15% using extended sources while the long-term stability has yet to be characterized. There are also several science related questions to be answered, for example, how the Earth’s atmosphere and surface variability contribute to the stability of the DNB measured radiances; how to separate them from instrument calibration stability; whether or not SI (International System of Units traceable active light sources can be designed and installed at selected sites to monitor the calibration stability, radiometric and geolocation accuracy, and point spread functions of the DNB; furthermore, whether or not such active light sources can be used for detecting environmental changes, such as aerosols. This paper explores the quantitative analysis of nightlight point sources, such as those from fishing vessels, bridges, and cities, using fundamental radiometry and radiative transfer, which would be useful for a number of applications including search and rescue in severe weather events, as well as calibration/validation of the DNB. Time series of the bridge light data are used to assess the stability of the light measurements and the calibration of VIIRS DNB. It was found that the light radiant power computed from the VIIRS DNB data matched relatively well with independent assessments based on the in situ light installations, although estimates have to be

  17. Compact, simple and robust cross polarized wave generation source of few-cycle, high-contrast pulses for seeding petawatt-class laser systems

    OpenAIRE

    Ramirez, Patricia; Papadopoulos, Dimitris N.; Hanna, Marc; Pellegrina, Alain; Friebel, Florence; Georges, Patrick; Druon, Frédéric

    2013-01-01

    International audience; A compact and robust, dual-crystal cross polarized wave generation setup combined with a hollow waveguide filter is implemented to deliver few-cycle, high-contrast laser pulses sourced from a commercial multipass Ti:Sa amplifier. The initial 25-fs pulses with a temporal contrast of 108 are shortened to 10 fs with an improved contrast of at least 10^10. The single nonlinear stage for spectral broadening and contrast enhancement of a commercial amplifier serves as an ide...

  18. A finger-free wrist-worn pulse oximeter for the monitoring of chronic obstructive pulmonary disease

    Science.gov (United States)

    Chu, Chang-Sheng; Chuang, Shuang-Chao; Lee, Yeh Wen; Fan, Chih-Hsun; Chung, Lung Pin; Li, Yu-Tang; Chen, Jyh-Chern

    2016-03-01

    Herein, a finger-free wrist-worn pulse oximeter is presented. This device allows patients to measure blood oxygen level and pulse rate without hindering their normal finger movement. This wrist-worn pulse oximeter is built with a reflectance oximetry sensor, which consists of light emitting diodes and photodiode light detectors located side by side. This reflectance oximetry sensor is covered with an optical element with micro structured surface. This micro structured optical element is designed to modulate photon propagation beneath the skin tissue so that the photoplethysmogram signals of reflected lights or backscattered lights detected by the photodetector are therefore enhanced.

  19. Differential-output B-dot and D-dot monitors for current and voltage measurements on a 20-MA, 3-MV pulsed-power accelerator

    Directory of Open Access Journals (Sweden)

    T. C. Wagoner

    2008-10-01

    Full Text Available We have developed a system of differential-output monitors that diagnose current and voltage in the vacuum section of a 20-MA 3-MV pulsed-power accelerator. The system includes 62 gauges: 3 current and 6 voltage monitors that are fielded on each of the accelerator’s 4 vacuum-insulator stacks, 6 current monitors on each of the accelerator’s 4 outer magnetically insulated transmission lines (MITLs, and 2 current monitors on the accelerator’s inner MITL. The inner-MITL monitors are located 6 cm from the axis of the load. Each of the stack and outer-MITL current monitors comprises two separate B-dot sensors, each of which consists of four 3-mm-diameter wire loops wound in series. The two sensors are separately located within adjacent cavities machined out of a single piece of copper. The high electrical conductivity of copper minimizes penetration of magnetic flux into the cavity walls, which minimizes changes in the sensitivity of the sensors on the 100-ns time scale of the accelerator’s power pulse. A model of flux penetration has been developed and is used to correct (to first order the B-dot signals for the penetration that does occur. The two sensors are designed to produce signals with opposite polarities; hence, each current monitor may be regarded as a single detector with differential outputs. Common-mode-noise rejection is achieved by combining these signals in a 50-Ω balun. The signal cables that connect the B-dot monitors to the balun are chosen to provide reasonable bandwidth and acceptable levels of Compton drive in the bremsstrahlung field of the accelerator. A single 50-Ω cable transmits the output signal of each balun to a double-wall screen room, where the signals are attenuated, digitized (0.5-ns/sample, numerically compensated for cable losses, and numerically integrated. By contrast, each inner-MITL current monitor contains only a single B-dot sensor. These monitors are fielded in opposite-polarity pairs. The two

  20. Differential B-dot and D-dot monitors for current and voltage measurements on a 20-MA 3-MV pulsed-power accelerator.

    Energy Technology Data Exchange (ETDEWEB)

    Shoup, Roy Willlam (ITT Industries, Albuquerque, NM); Gilliland, Terrance Leo (Ktech Corporation, Albuquerque, NM); Lee, James R.; Speas, Christopher Shane; Kim, Alexandre A. (High Current Electronic Institute, Russian Academy of Sciences, Tomsk, Russia); Struve, Kenneth William; York, Mathew William; Leifeste, Gordon T.; Rochau, Gregory Alan; Sharpe, Arthur William; Stygar, William A.; Porter, John Larry Jr.; Wagoner, Tim C. (Ktech Corporation, Albuquerque, NM); Reynolds, Paul Gerard (Team Specialty Products Corporation, Albuquerque, NM); Slopek, Jeffrey Scott (Ktech Corporation, Albuquerque, NM); Moore, William B. S.; Dinwoodie, Thomas Albert (Ktech Corporation, Albuquerque, NM); Woodring, R. M. (Ktech Corporation, Albuquerque, NM); Broyles, Robin Scott (Ktech Corporation, Albuquerque, NM); Mills, Jerry Alan; Melville, J. A. (Prodyn Technologies Incorporated, Albuquerque, NM); Dudley, M. E. (Ktech Corporation, Albuquerque, NM); Androlewicz, K. E. (Ktech Corporation, Albuquerque, NM); Mourning, R. W. (Ktech Corporation, Albuquerque, NM); Moore, J. K. (Ktech Corporation, Albuquerque, NM); Serrano, Jason Dimitri (Ktech Corporation, Albuquerque, NM); Ives, H. C. (EG& G, Albuquerque, NM); Johnson, M. F. (Team Specialty Products Corporation, Albuquerque, NM); Peyton, B. P. (Ktech Corporation, Albuquerque, NM); Leeper, Ramon Joe; Savage, Mark Edward; Donovan, Guy Louis; Spielman, R. B. (Ktech Corporation, Albuquerque, NM); Seamen, Johann F.

    2007-12-01

    We have developed a system of differential-output monitors that diagnose current and voltage in the vacuum section of a 20-MA 3-MV pulsed-power accelerator. The system includes 62 gauges: 3 current and 6 voltage monitors that are fielded on each of the accelerator's 4 vacuum-insulator stacks, 6 current monitors on each of the accelerator's 4 outer magnetically insulated transmission lines (MITLs), and 2 current monitors on the accelerator's inner MITL. The inner-MITL monitors are located 6 cm from the axis of the load. Each of the stack and outer-MITL current monitors comprises two separate B-dot sensors, each of which consists of four 3-mm-diameter wire loops wound in series. The two sensors are separately located within adjacent cavities machined out of a single piece of copper. The high electrical conductivity of copper minimizes penetration of magnetic flux into the cavity walls, which minimizes changes in the sensitivity of the sensors on the 100-ns time scale of the accelerator's power pulse. A model of flux penetration has been developed and is used to correct (to first order) the B-dot signals for the penetration that does occur. The two sensors are designed to produce signals with opposite polarities; hence, each current monitor may be regarded as a single detector with differential outputs. Common-mode-noise rejection is achieved by combining these signals in a 50-{Omega} balun. The signal cables that connect the B-dot monitors to the balun are chosen to provide reasonable bandwidth and acceptable levels of Compton drive in the bremsstrahlung field of the accelerator. A single 50-{omega} cable transmits the output signal of each balun to a double-wall screen room, where the signals are attenuated, digitized (0.5-ns/sample), numerically compensated for cable losses, and numerically integrated. By contrast, each inner-MITL current monitor contains only a single B-dot sensor. These monitors are fielded in opposite-polarity pairs. The two

  1. The Doppler Effect based acoustic source separation for a wayside train bearing monitoring system

    Science.gov (United States)

    Zhang, Haibin; Zhang, Shangbin; He, Qingbo; Kong, Fanrang

    2016-01-01

    Wayside acoustic condition monitoring and fault diagnosis for train bearings depend on acquired acoustic signals, which consist of mixed signals from different train bearings with obvious Doppler distortion as well as background noises. This study proposes a novel scheme to overcome the difficulties, especially the multi-source problem in wayside acoustic diagnosis system. In the method, a time-frequency data fusion (TFDF) strategy is applied to weaken the Heisenberg's uncertainty limit for a signal's time-frequency distribution (TFD) of high resolution. Due to the Doppler Effect, the signals from different bearings have different time centers even with the same frequency. A Doppler feature matching search (DFMS) algorithm is then put forward to locate the time centers of different bearings in the TFD spectrogram. With the determined time centers, time-frequency filters (TFF) are designed with thresholds to separate the acoustic signals in the time-frequency domain. Then the inverse STFT (ISTFT) is taken and the signals are recovered and filtered aiming at each sound source. Subsequently, a dynamical resampling method is utilized to remove the Doppler Effect. Finally, accurate diagnosis for train bearing faults can be achieved by applying conventional spectrum analysis techniques to the resampled data. The performance of the proposed method is verified by both simulated and experimental cases. It shows that it is effective to detect and diagnose multiple defective bearings even though they produce multi-source acoustic signals.

  2. Passive monitoring for near surface void detection using traffic as a seismic source

    Science.gov (United States)

    Zhao, Y.; Kuzma, H. A.; Rector, J.; Nazari, S.

    2009-12-01

    In this poster we present preliminary results based on our several field experiments in which we study seismic detection of voids using a passive array of surface geophones. The source of seismic excitation is vehicle traffic on nearby roads, which we model as a continuous line source of seismic energy. Our passive seismic technique is based on cross-correlation of surface wave fields and studying the resulting power spectra, looking for "shadows" caused by the scattering effect of a void. High frequency noise masks this effect in the time domain, so it is difficult to see on conventional traces. Our technique does not rely on phase distortions caused by small voids because they are generally too tiny to measure. Unlike traditional impulsive seismic sources which generate highly coherent broadband signals, perfect for resolving phase but too weak for resolving amplitude, vehicle traffic affords a high power signal a frequency range which is optimal for finding shallow structures. Our technique results in clear detections of an abandoned railroad tunnel and a septic tank. The ultimate goal of this project is to develop a technology for the simultaneous imaging of shallow underground structures and traffic monitoring near these structures.

  3. Note: Design and tests of a 13 kA-6.5 kV thyristor switch for a pulsed inductive vacuum ultraviolet source.

    Science.gov (United States)

    Teske, C; Lee, B-J; Jacoby, J; Schweizer, W; Sun, J Chao

    2010-04-01

    In this paper, the design, construction, and test procedure of a closing switch prototype based on thyristors is described. In particular, details are given about the design criteria and about the triggering board architecture, which is a high side biased, self supplied unit using the electrical energy derived from a local snubber network for the gate drive. The structure guarantees a hard firing gate pulse for the required high dI/dt application. Further, the results of the prototype tests are presented and discussed. The stack assembly has a holding voltage of 6.5 kV and is used for switching a series resonant circuit with a ringing frequency of 12 kHz for a pulsed inductive vacuum ultraviolet source. Maximum current amplitudes of 13 kA and pulse energies of more than 600 J were switched during the test procedure.

  4. Optical Cherenkov radiation by cascaded nonlinear interaction: an efficient source of few-cycle energetic near- to mid-IR pulses.

    Science.gov (United States)

    Bache, M; Bang, O; Zhou, B B; Moses, J; Wise, F W

    2011-11-07

    When ultrafast noncritical cascaded second-harmonic generation of energetic femtosecond pulses occur in a bulk lithium niobate crystal optical Cherenkov waves are formed in the near- to mid-IR. Numerical simulations show that the few-cycle solitons radiate Cherenkov (dispersive) waves in the λ = 2.2 - 4.5 μm range when pumping at λ₁ = 1.2 - 1.8 μm. The exact phase-matching point depends on the soliton wavelength, and we show that a simple longpass filter can separate the Cherenkov waves from the solitons. The Cherenkov waves are born few-cycle with an excellent Gaussian pulse shape, and the conversion efficiency is up to 25%. Thus, optical Cherenkov waves formed with cascaded nonlinearities could become an efficient source of energetic near- to mid-IR few-cycle pulses.

  5. Powering embedded electronics for wind turbine monitoring using multi-source energy harvesting techniques

    Science.gov (United States)

    Anton, S. R.; Taylor, S. G.; Raby, E. Y.; Farinholt, K. M.

    2013-03-01

    With a global interest in the development of clean, renewable energy, wind energy has seen steady growth over the past several years. Advances in wind turbine technology bring larger, more complex turbines and wind farms. An important issue in the development of these complex systems is the ability to monitor the state of each turbine in an effort to improve the efficiency and power generation. Wireless sensor nodes can be used to interrogate the current state and health of wind turbine structures; however, a drawback of most current wireless sensor technology is their reliance on batteries for power. Energy harvesting solutions present the ability to create autonomous power sources for small, low-power electronics through the scavenging of ambient energy; however, most conventional energy harvesting systems employ a single mode of energy conversion, and thus are highly susceptible to variations in the ambient energy. In this work, a multi-source energy harvesting system is developed to power embedded electronics for wind turbine applications in which energy can be scavenged simultaneously from several ambient energy sources. Field testing is performed on a full-size, residential scale wind turbine where both vibration and solar energy harvesting systems are utilized to power wireless sensing systems. Two wireless sensors are investigated, including the wireless impedance device (WID) sensor node, developed at Los Alamos National Laboratory (LANL), and an ultra-low power RF system-on-chip board that is the basis for an embedded wireless accelerometer node currently under development at LANL. Results indicate the ability of the multi-source harvester to successfully power both sensors.

  6. An integrated, open-source set of tools for urban vulnerability monitoring from Earth observation data

    Science.gov (United States)

    De Vecchi, Daniele; Harb, Mostapha; Dell'Acqua, Fabio; Aurelio Galeazzo, Daniel

    2015-04-01

    Aim: The paper introduces an integrated set of open-source tools designed to process medium and high-resolution imagery with the aim to extract vulnerability indicators [1]. Problem: In the context of risk monitoring [2], a series of vulnerability proxies can be defined, such as the extension of a built-up area or buildings regularity [3]. Different open-source C and Python libraries are already available for image processing and geospatial information (e.g. OrfeoToolbox, OpenCV and GDAL). They include basic processing tools but not vulnerability-oriented workflows. Therefore, it is of significant importance to provide end-users with a set of tools capable to return information at a higher level. Solution: The proposed set of python algorithms is a combination of low-level image processing and geospatial information handling tools along with high-level workflows. In particular, two main products are released under the GPL license: source code, developers-oriented, and a QGIS plugin. These tools were produced within the SENSUM project framework (ended December 2014) where the main focus was on earthquake and landslide risk. Further development and maintenance is guaranteed by the decision to include them in the platform designed within the FP 7 RASOR project . Conclusion: With the lack of a unified software suite for vulnerability indicators extraction, the proposed solution can provide inputs for already available models like the Global Earthquake Model. The inclusion of the proposed set of algorithms within the RASOR platforms can guarantee support and enlarge the community of end-users. Keywords: Vulnerability monitoring, remote sensing, optical imagery, open-source software tools References [1] M. Harb, D. De Vecchi, F. Dell'Acqua, "Remote sensing-based vulnerability proxies in the EU FP7 project SENSUM", Symposium on earthquake and landslide risk in Central Asia and Caucasus: exploiting remote sensing and geo-spatial information management, 29-30th January 2014

  7. Numerical analysis of the beam position monitor pickup for the Iranian light source facility

    Science.gov (United States)

    Shafiee, M.; Feghhi, S. A. H.; Rahighi, J.

    2017-03-01

    In this paper, we describe the design of a button type Beam Position Monitor (BPM) for the low emittance storage ring of the Iranian Light Source Facility (ILSF). First, we calculate sensitivities, induced power and intrinsic resolution based on solving Laplace equation numerically by finite element method (FEM), in order to find the potential at each point of BPM's electrode surface. After the optimization of the designed BPM, trapped high order modes (HOM), wakefield and thermal loss effects are calculated. Finally, after fabrication of BPM, it is experimentally tested by using a test-stand. The results depict that the designed BPM has a linear response in the area of 2×4 mm2 inside the beam pipe and the sensitivity of 0.080 and 0.087 mm-1 in horizontal and vertical directions. Experimental results also depict that they are in a good agreement with numerical analysis.

  8. Finnish experiences of health monitoring: local, regional, and national data sources for policy evaluation

    Directory of Open Access Journals (Sweden)

    Katri Kilpeläinen

    2016-02-01

    Full Text Available Background: Finland has a long tradition of gathering information about the health and welfare of the adult population. Design: Surveys and administrative registers form the basis for national and local health monitoring in Finland. Results: Different data sources are used in Finland to develop key indicators, which can be used to evaluate how the national health policy targets have been met in different parts of the country and in different population subgroups. Progress has been shown in chronic disease risk factors, such as smoking reduction. However, some health policy targets have not been met. Socioeconomic health differences, for example, have remained large compared with other European countries. Conclusion: Although data availability for key health indicators is good in Finland, there is a need for wider and more comprehensive use of this information by political decision-makers and healthcare professionals.

  9. Monitoring of potentially toxic cyanobacteria using an online multi-probe in drinking water sources.

    Science.gov (United States)

    Zamyadi, A; McQuaid, N; Prévost, M; Dorner, S

    2012-02-01

    Toxic cyanobacteria threaten the water quality of drinking water sources across the globe. Two such water bodies in Canada (a reservoir on the Yamaska River and a bay of Lake Champlain in Québec) were monitored using a YSI 6600 V2-4 (YSI, Yellow Springs, Ohio, USA) submersible multi-probe measuring in vivo phycocyanin (PC) and chlorophyll-a (Chl-a) fluorescence, pH, dissolved oxygen, conductivity, temperature, and turbidity in parallel. The linearity of the in vivo fluorescence PC and Chl-a probe measurements were validated in the laboratory with Microcystis aeruginosa (r(2) = 0.96 and r(2) = 0.82 respectively). Under environmental conditions, in vivo PC fluorescence was strongly correlated with extracted PC (r = 0.79) while in vivo Chl-a fluorescence had a weaker relationship with extracted Chl-a (r = 0.23). Multiple regression analysis revealed significant correlations between extracted Chl-a, extracted PC and cyanobacterial biovolume and in vivo fluorescence parameters measured by the sensors (i.e. turbidity and pH). This information will help water authorities select the in vivo parameters that are the most useful indicators for monitoring cyanobacteria. Despite highly toxic cyanobacterial bloom development 10 m from the drinking water treatment plant's (DWTP) intake on several sampling dates, low in vivo PC fluorescence, cyanobacterial biovolume, and microcystin concentrations were detected in the plant's untreated water. The reservoir's hydrodynamics appear to have prevented the transport of toxins and cells into the DWTP which would have deteriorated the water quality. The multi-probe readings and toxin analyses provided critical evidence that the DWTP's untreated water was unaffected by the toxic cyanobacterial blooms present in its source water.

  10. Oscillatory hydraulic testing as a strategy for NAPL source zone monitoring: Laboratory experiments

    Science.gov (United States)

    Zhou, YaoQuan; Cardiff, Michael

    2017-05-01

    Non-aqueous phase liquids (NAPLs) have a complex mode of transport in heterogeneous aquifers, which can result in pools and lenses of NAPLs (the ;source zone;) that are difficult to detect and can cause long-term contamination via slow dissolution into groundwater (the ;dissolved plume;). Characterizing the extent and evolution of NAPL contamination within the source zone is a useful strategy for designing and adapting appropriate remedial actions at many contaminated sites. As a NAPL flows into a given aquifer volume, the effective hydraulic conductivity (K) and specific storage (Ss) of the volume changes associated with the viscosity and compressibility of the impinging fluid, meaning that NAPL movement may be detectable with hydraulic testing. Recently, the use of oscillatory pumping tests - in which sinusoidal pumping variations are implemented and oscillatory pressure changes are detected at monitoring locations - has been suggested as a low-impact hydraulic testing strategy for characterizing aquifer properties (Cardiff et al., 2013; Zhou et al., 2016). Here, we investigate this strategy in an experimental laboratory sandbox where dyed vegetable oil is injected and allowed to migrate as a NAPL. Initial qualitative analyses demonstrate that measurable changes in pressure signal amplitude and phase provide clear evidence for NAPL plume emplacement and migration. Using the approach developed in Zhou et al. (2016), we then apply tomographic analyses to estimate the location of effective K changes (representing fluid changes) and their movement throughout time. This approach provides a method for monitoring ongoing NAPL movement without net extraction or injection of fluid, making it advantageous in field remediation applications.

  11. Geosfear? - Overcoming System Boundaries by Open-source Based Monitoring of Spatio-temporal Processes

    Science.gov (United States)

    Brandt, T.; Schima, R.; Goblirsch, T.; Paschen, M.; Francyk, B.; Bumberger, J.; Zacharias, S.; Dietrich, P.; Rubin, Y.; Rinke, K.; Fleckenstein, J. H.; Schmidt, C.; Vieweg, M.

    2016-12-01

    The impact of global change, intensive agriculture and complex interactions between humans and the environment show different effects on different scales. However, the desire to obtain a better understanding of ecosystems and process dynamics in nature accentuates the need for observing these processes at higher temporal and spatial resolutions. Especially with regard to the process dynamics and heterogeneity of rivers and catchment areas, a comprehensive monitoring of the ongoing processes and effects remains to be a challenging issue. What we need are monitoring systems which can collect most diverse data across different environmental compartments and scales. Today, open-source based electronics and innovative sensors and sensor components are offering a promising approach to investigate new possibilities of mobile data acquisition to improve our understanding of the geosphere. To start with, we have designed and implemented a multi-operable, embedded Linux platform for fast integration of different sensors within a single infrastructure. In addition, a GPS module in combination with a GSM transmitter ensures the synchronization and geo-referencing of all data, no matter how old-fashioned the sensors are. To this end, initial field experiments were conducted at a 3rd order stream in the Central German Lowland. Here, we linked in-stream DOC inputs with subsurface metabolism by coupling miniaturized DOC sensor probes with a modified vertical oxygen profiler in situ. Starting from metrological observations to water quality and subsurface conditions, the overarching goal is the detection of interlinked process dynamics across highly reactive biogeochemical interfaces. Overall, the field experiments demonstrated the feasibility of this emerging technology and its potential towards a cutting-edge strategy based on a holistic and integrated process. Now, we are only a few steps away from realizing adaptive and event-triggered observations close to real

  12. Using swept source optical coherence tomography to monitor wound healing in tissue engineered skin

    Science.gov (United States)

    Smith, L. E.; Lu, Z.; Bonesi, M.; Smallwood, R.; Matcher, S. J.; MacNeil, S.

    2010-02-01

    There is an increasing need for a robust simple to use non-invasive imaging technology for monitoring tissue engineered constructs as they develop. We have applied optical coherence tomography (OCT), a relatively new optical technique, to image tissue engineered constructs. Our aim was to evaluate the use of swept-source optical coherence tomography (SSOCT) to non-invasively image reconstructed skin as it developed over several weeks. The epidermis of the reconstructed skin was readily distinguished from the neodermis when examined with standard histology - a destructive imaging technique - of samples. The development of reconstructed skin based on deepithelialised acellular dermis (DED) was accurately monitored with SS-OCT over three weeks and confirmed with conventional histology. It was also possible to image changes in the epidermis due to the presence of melanoma and the healing of these 3D models after wounding with a scalpel, with or without the addition of a fibrin clot. SS-OCT is proving to be a valuable tool in tissue engineering, showing great promise for the non-invasive imaging of optically turbid tissue engineered constructs, including tissue engineered skin.

  13. A monitoring and control system for the ISOLDE resonance laser ion source RILIS

    Energy Technology Data Exchange (ETDEWEB)

    Rossel, Ralf [Engineering Department, CERN, Geneva (Switzerland); Institut fuer Physik, Johannes Gutenberg-Universitaet, Mainz (Germany); Fachbereich Design Informatik Medien, Hochschule RheinMain, Wiesbaden (Germany); Fedosseev, Valentin; Marsh, Bruce [Engineering Department, CERN, Geneva (Switzerland); Rothe, Sebastian [Engineering Department, CERN, Geneva (Switzerland); Institut fuer Physik, Johannes Gutenberg-Universitaet, Mainz (Germany); Wendt, Klaus [Institut fuer Physik, Johannes Gutenberg-Universitaet, Mainz (Germany)

    2012-07-01

    The RILIS laser ion source is one of the central components of the ISOLDE on-line isotope production facility. A record of about 2500 hours of on-line operation for the year 2011 shows the major importance and high demand for RILIS which provides radioactive ion beams of various elements with the highest efficiency and unmatched isobaric purity. The RILIS is currently operated 24/7 with the operators continuously present to control and possibly correct the crucial laser parameters, i.e. wavelength, output powers and beam positions of all individual lasers in use. Moreover, the operator acts as contact person for the ISOLDE user to inform about its current status. Deploying a widely automated, network-based monitoring and control software will not only enable manpower to devote their time to system improvement rather than supervision but also greatly improve health issues and work safety as stay in areas with increased levels of radiation exposition will be significantly reduced. The on-going software and hardware development covers the four key aspects: Machine protection, monitoring of beam parameters, automated correction and a RILIS status display for the users. The concept and the status of implementation are presented.

  14. Remote Operating Monitoring Of Spatial Stability Magnets On A Kurchatov Source Of Synchrotron Radiation

    CERN Document Server

    Barkovsky, E V; Martynenko, V V; Novikov, V A; Udin, L I

    2004-01-01

    During operation of the accelerator because of a nonuniform warm -up of the ring base and constructions of installation there are angular and linear displacements of bending and focusing magnets of a Big Accelerator Ring (BR) of a Kurchatov Source of Synchrotron Radiation. With the purpose of remote operating monitoring of a spatial position of elements BR was used anglemetrical control and measuring system with digital and analog registration in a real time mode. The results of the first stage of a monitoring BR have shown high informativity of the given instrumental - methodical means. The basic radiants of cyclical thermoelastic alternating strains are detected; the amplitudes of angular and linear displacements of magnets from different internal factors evaluated during operation of the accelerator. Is established, that the maximum radial angular and linear displacements of magnets are watched in 3,5-4 day after switching on of installation and achieve in max 30-35 seconds of an arc or 120-150 microns in ...

  15. Pulse-to-pulse Diagnostics at High Reprate

    Science.gov (United States)

    Green, Bertram; Kovalev, Sergey; Golz, Torsten; Stojanovich, Nikola; Fisher, Alan; Kampfrath, Tobias; Gensch, Michael

    2016-03-01

    Femtosecond level diagnostic and control of sub-picosecond electron bunches is an important topic in modern accelerator research. At the same time new linear electron accelerators based on quasi-CW SRF technology will be the drivers of many future 4th Generation lightsources such as X-ray free electron lasers. A high duty cycle, high stability and online pulse to pulse diagnostic at these new accelerators are crucial ingredients to the success of these large scale facilities. A novel THz based online monitor concept is presented that has the potential to give access to pulse to pulse information on bunch form, arrival time and energy at high repetition rate and down to sub pC charges. We furthermore show experimentally that pulse to pulse arrival time measurements can be used to perform pump-probe experiments with a temporal resolution in the few-fs regime and an exceptional dynamic range. Our scheme has been tested at the superradiant test facility TELBE, but can be readily transferred to other SRF accelerator driven photon sources, such as X-FELs.

  16. Analysis of recordings from underwater controlled sources in the Pacific Ocean received by the International Monitoring System (IMS) of the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO)

    Science.gov (United States)

    Yamada, Tomoaki; Zampolli, Mario; Haralabus, Georgios; Heaney, Kevin; Prior, Mark; Isse, Takeshi

    2016-04-01

    Controlled impulsive scientific underwater sound sources in the Northwestern Pacific were observed at two IMS hydroacoustic stations in the Pacific Ocean. Although these experiments were conducted with the aim of studying the physical properties of the plate boundaries inside the Earth, they are also suitable for the investigation of long range underwater acoustic detections. In spite of the fact that the energy of these controlled impulsive scientific sources is significantly smaller than that of nuclear explosions, the signals were obtained by IMS hydrophone stations thousands of kilometres away and also by distant ocean bottom instruments operated by various Institutes, such as the Earthquake Research Institute, University of Tokyo. These experiments provide calibrated (yield, time, location) long-range acoustic transmissions, which enable one to examine the physics of long-range acoustic propagation and to verify the capabilities of the CTBTO IMS network to detect even small explosions.The two IMS stations used are H03 (Juan Fernandez Island, Chile) off the coast of Chile in the Southeastern Pacific and H11 (Wake Island, USA) in the Western Pacific. Both stations consist of two triplets of hydrophones in the SOFAR channel, which monitor the oceans for signs of nuclear explosions. H03 detected low-yield explosions above flat terrain at distances of 15,000 km across the Pacific as well as explosions above the landward slope off the coast of Japan at distances above 16,000 km across the Pacific. These records showed that source signatures, such as short duration and bubble pulses, were preserved over the long propagation distances. It was found that the observed maximum amplitudes from each source exhibit order of magnitude variations even when the yield and detonation depth are the same. The experimental data and transmission loss simulations suggest that bathymetric features around the sources and between the sources and the receivers are the main causes for

  17. Scheduling and calibration strategy for continuous radio monitoring of 1700 sources every three days

    Science.gov (United States)

    Max-Moerbeck, Walter

    2014-08-01

    The Owens Valley Radio Observatory 40 meter telescope is currently monitoring a sample of about 1700 blazars every three days at 15 GHz, with the main scientific goal of determining the relation between the variability of blazars at radio and gamma-rays as observed with the Fermi Gamma-ray Space Telescope. The time domain relation between radio and gamma-ray emission, in particular its correlation and time lag, can help us determine the location of the high-energy emission site in blazars, a current open question in blazar research. To achieve this goal, continuous observation of a large sample of blazars in a time scale of less than a week is indispensable. Since we only look at bright targets, the time available for target observations is mostly limited by source observability, calibration requirements and slewing of the telescope. Here I describe the implementation of a practical solution to this scheduling, calibration, and slewing time minimization problem. This solution combines ideas from optimization, in particular the traveling salesman problem, with astronomical and instrumental constraints. A heuristic solution using well established optimization techniques and astronomical insights particular to this situation, allow us to observe all the sources in the required three days cadence while obtaining reliable calibration of the radio flux densities. Problems of this nature will only be more common in the future and the ideas presented here can be relevant for other observing programs.

  18. IMPLEMENTATION OF OPEN-SOURCE WEB MAPPING TECHNOLOGIES TO SUPPORT MONITORING OF GOVERNMENTAL SCHEMES

    Directory of Open Access Journals (Sweden)

    B. R. Pulsani

    2015-10-01

    Full Text Available Several schemes are undertaken by the government to uplift social and economic condition of people. The monitoring of these schemes is done through information technology where involvement of Geographic Information System (GIS is lacking. To demonstrate the benefits of thematic mapping as a tool for assisting the officials in making decisions, a web mapping application for three government programs such as Mother and Child Tracking system (MCTS, Telangana State Housing Corporation Limited (TSHCL and Ground Water Quality Mapping (GWQM has been built. Indeed the three applications depicted the distribution of various parameters thematically and helped in identifying the areas with higher and weaker distributions. Based on the three applications, the study tends to find similarities of many government schemes reflecting the nature of thematic mapping and hence deduces to implement this kind of approach for other schemes as well. These applications have been developed using SharpMap Csharp library which is a free and open source mapping library for developing geospatial applications. The study highlights upon the cost benefits of SharpMap and brings out the advantage of this library over proprietary vendors and further discusses its advantages over other open source libraries as well.

  19. Campus Monitoring System for Annamalai University by Open Source Software and Modern Surveying Application

    Directory of Open Access Journals (Sweden)

    K.R. VENKATESH

    2016-06-01

    Full Text Available In urban planning management, the third dimension is becoming a necessity. Using 3D GIS model offers a flexible, interactive system while providing one of the best visual interpretation of data, which supports planning and decision processes for the planner. GIS-based maps and visualizations greatly assist in understanding information about the location. Since, interpretation of 3D data is cost effective using open source software than any other to do analysis. In this study, across multiple domains, 3D models were utilized to understand and document the state of the art. An effort has been taken to overcome this problem and to develop the Campus Monitoring System. In particular, a campus map was proposed which covers four main aspects: Geo referencing, 2D smart campus map, vertical laser measurements by spike application and 3D visualization with attribute data. Finally, the results, problems and limitations of the achieved products were investigated in order to evaluate and confirm the reliability and convenience of open source software.

  20. Design of Pulsed Eddy Current Exciting Source Based on Virtual Instrument%基于虚拟仪器的脉冲涡流激励源设计

    Institute of Scientific and Technical Information of China (English)

    邱选兵; 魏计林; 崔小朝; 黄祥康; 刘路路

    2013-01-01

    Pulsed eddy current testing is a new research field of eddy current testing technology. A square waveform with adjusting duty is employed as exciting source. Combined with virtual instrument technology, the pulsed eddy current exciting source of direct digital synthesizer is designed based on USB interface. The experimental results indicate that the exciting source has the performance of the continuous adjustable frequency (0. 5 — 500 kHz) and duty (10% — 90%), high resolution (0. 011 6 Hz) , stability, friendly interface and so on. It is very suitable for the driving requirements of the pulsed eddy current probe, and has some application prospect.%脉冲涡流检测是电涡流检测技术的一个最新研究,激励源采用一定占空比的方波信号.结合虚拟仪器技术,设计了一种USB接口的直接数字合成的脉冲涡流激励源.实验结果表明该激励源有占空比(10%~90%),频率(0.5 k~500 kHz)连续可调,分辨率高(0.011 6 Hz),稳定可靠,界面友好等优点,能够满足脉冲涡流探头驱动要求,具有一定应用前景.

  1. High current H{sub 2}{sup +} and H{sub 3}{sup +} beam generation by pulsed 2.45 GHz electron cyclotron resonance ion source

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Yuan; Peng, Shixiang, E-mail: sxpeng@pku.edu.cn; Ren, Haitao; Zhao, Jie; Chen, Jia; Zhang, Tao; Guo, Zhiyu [State Key Laboratory of Nuclear Physics and Technology and Institute of Heavy Ion Physics, Peking University, Beijing 100871 (China); Zhang, Ailin [University of Chinese Academy of Sciences, Beijing 100049 (China); Chen, Jia' er [State Key Laboratory of Nuclear Physics and Technology and Institute of Heavy Ion Physics, Peking University, Beijing 100871 (China); University of Chinese Academy of Sciences, Beijing 100049 (China)

    2014-02-15

    The permanent magnet 2.45 GHz electron cyclotron resonance ion source at Peking University can produce more than 100 mA hydrogen ion beam working at pulsed mode. For the increasing requirements of cluster ions (H{sub 2}{sup +} and H{sub 3}{sup +}) in linac and cyclotron, experimental study was carried out to further understand the hydrogen plasma processes in the ion source for the generation of cluster ions. The constituents of extracted beam have been analyzed varying with the pulsed duration from 0.3 ms to 2.0 ms (repetition frequency 100 Hz) at different operation pressure. The fraction of cluster ions dramatically increased when the pulsed duration was lower than 0.6 ms, and more than 20 mA pure H{sub 3}{sup +} ions with fraction 43.2% and 40 mA H{sub 2}{sup +} ions with fraction 47.7% were obtained when the operation parameters were adequate. The dependence of extracted ion fraction on microwave power was also measured at different pressure as the energy absorbed by plasma will greatly influence electron temperature and electron density then the plasma processes in the ion source. More details will be presented in this paper.

  2. Aquifers survey in the context of source rocks exploitation: from baseline acquisition to long term monitoring

    Science.gov (United States)

    Garcia, Bruno; Rouchon, Virgile; Deflandre, Jean-Pierre

    2017-04-01

    Producing hydrocarbons from source rocks (like shales: a mix of clays, silts, carbonate and sandstone minerals containing matured organic matter, i.e. kerogen oil and gas, but also non-hydrocarbon various species of chemical elements including sometimes radioactive elements) requires to create permeability within the rock matrix by at least hydraulically fracturing the source rock. It corresponds to the production of hydrocarbon fuels that have not been naturally expelled from the pressurized matured source rock and that remain trapped in the porosity or/and kerogen porosity of the impermeable matrix. Azimuth and extent of developed fractures can be respectively determined and mapped by monitoring the associated induced microseismicity. This allows to have an idea of where and how far injected fluids penetrated the rock formation. In a geological context, aquifers are always present in the vicinity -or on fluid migration paths- of such shale formations: deep aquifers (near the shale formation) up to sub-surface and potable (surface) aquifers. Our purpose will be to track any unsuitable invasion or migration of chemicals specifies coming from matured shales of production fluids including both drilling and fracturing ones into aquifers. Our objective is to early detect and alarm of any anomaly to avoid any important environmental issue. The approach consists in deploying a specific sampling tool within a well to recover formation fluids and to run a panoply of appropriate laboratory tests to state on fluid characteristics. Of course for deep aquifers, such a characterization process may consider aquifer properties prior producing shale oil and gas, as they may contain naturally some chemical species present in the source rocks. One can also consider that a baseline acquisition could be justified in case of possible previous invasion of non-natural fluids in the formation under survey (due to any anthropogenic action at surface or in the underground). The paper aims

  3. Laser Gas-Analyser for Monitoring a Source of Gas Pollution

    Directory of Open Access Journals (Sweden)

    V. A. Gorodnichev

    2015-01-01

    Full Text Available Currently, the problem of growing air pollution of the Earth is of relevance. Many countries have taken measures to protect the environment in order to limit the negative anthropogenic impacts.In such a situation an objective information on the actual content of pollutants in the atmosphere is of importance. For operational inspection of the pollutant concentrations and for monitoring pollution sources, it is necessary to create high-speed high-sensitivity gas analysers.Laser meters are the most effective to provide operational remote and local inspection of gas pollution of the Earth atmosphere.Laser meter for routine gas analysis should conduct operational analysis of the gas mixture (air. For this a development of appropriate information support is required.Such information support should include a database with absorption coefficients of pollutants (specific to potential sources of pollution at possible measuring wavelengths (holding data for a particular emitter of the laser meter and an efficient algorithms to search the measuring wavelengths and conduct a quantitative analysis of gas mixtures.Currently, the issues, important for practice and related to the development of information support for the laser gas analyzer to conduct important for practice routine measurements remain unclear.In this paper we develop an algorithm to provide an operational search of the measuring wavelengths of laser gas analyser and an algorithm to recover quantitively the gaseous component concentrations of controlled gas mixture from the laser multi-spectral measurements that take into account a priori information about the source-controlled gas pollution and do not require a large amount of computation. The method of mathematical simulation shows the effectiveness of the algorithms described both for seach of measuring wavelengths and for quantitative analysis of gas releases.

  4. Determination of kinetic parameters for monitoring source driven subcritical transmutation devices

    Energy Technology Data Exchange (ETDEWEB)

    Becker, Maarten

    2014-03-15

    ADS are considered as an option for the irradiation facility in partitioning and transmutation concepts for highly radioactive waste from spent nuclear fuel. Due to the hard neutron energy spectrum and the subcriticality of the reactor ADS provide a good compromise between transmutation performance and safety aspects. For the safe operation, but also for the overall optimization of the facility, the determination of the subcriticality level is essential. To investigate experimental methods in Pulsed Neutron Source (PNS) experiments for the determination of the subcriticality level the ADS experiment YALINA-Thermal is thoroughly analyzed in this work. The experiment has been performed from 2005-2010 in Minsk, Belarus. Most of the related experimental methods rely on point kinetic equations. This approach introduces two main approximations. Firstly, the point kinetic equation cannot describe the transition of the neutron distribution from the source operation to the source shutdown. After shutdown, the neutron population would redistribute to establish the fundamental decay mode. This violates the point kinetic assumption of neutron flux spectra constant in time. Secondly, to calculate kinetic parameters like the neutron mean generation time and the effective delayed neutron fraction the neutron flux distribution of the effective multiplication factor equation is typically used, which is equivalent to an artificial critical steady-state reactor. However, it is the time-dependence of the decay of the neutron populations including their redistribution in space and energy, which affects the analyzed kinetic parameters. Consequently, this work aims for the accurate simulation of these phenomena with particular emphasis on the quality of the effective neutron cross sections. In this work new microscopic master libraries based on the JEFF 3.1, JEFF 3.1.1 and ENDF/B VII.0 evaluations are developed with a general purpose 350 energy groups structure for the deterministic

  5. Long-pulse production of high current negative ion beam by using actively temperature controlled plasma grid for JT-60SA negative ion source

    Energy Technology Data Exchange (ETDEWEB)

    Kojima, A.; Hanada, M.; Yoshida, M.; Umeda, N.; Hiratsuka, J.; Kashiwagi, M.; Tobari, H.; Watanabe, K. [Japan Atomic Energy Agency, 801-1, Mukoyama, Naka 311-0193 (Japan); Grisham, L. R. [Princeton Plasma Physics Laboratory, Princeton, NJ 08543 (United States)

    2015-04-08

    The temperature control system of the large-size plasma grid has been developed to realize the long pulse production of high-current negative ions for JT-60SA. By using this prototype system for the JT-60SA ion source, 15 A negative ions has been sustained for 100 s for the first time, which is three times longer than that obtained in JT-60U. In this system, a high-temperature fluorinated fluid with a high boiling point of 270 degree Celsius is circulated in the cooling channels of the plasma grids (PG) where a cesium (Cs) coverage is formed to enhance the negative ion production. Because the PG temperature control had been applied to only 10% of the extraction area previously, the prototype PG with the full extraction area (110 cm × 45 cm) was developed to increase the negative ion current in this time. In the preliminary results of long pulse productions of high-current negative ions at a Cs conditioning phase, the negative ion production was gradually degraded in the last half of 100 s pulse where the temperature of an arc chamber wall was not saturated. From the spectroscopic measurements, it was found that the Cs flux released from the wall might affect to the negative ion production, which implied the wall temperature should be kept low to control the Cs flux to the PG for the long-pulse high-current production. The obtained results of long-pulse production and the PG temperature control method contributes the design of the ITER ion source.

  6. Pulse on Pulse

    DEFF Research Database (Denmark)

    Schmidt, Ulrik; Carlson, Merete

    2012-01-01

    Pulse on Pulse” investigates the relation between signifying processes and non-signifying material dynamism in the installation Pulse Room (2006-) by Mexican Canadian artist Rafael Lozano-Hemmer. In Pulse Room the sense of pulse is ambiguous. Biorhythms are transmitted from the pulsing energy...... and pulsating ‘room’. Hence, the visitors in Pulse Room are invited into a complex scenario that continuously oscillates between various aspects of signification (the light bulbs representing individual lives; the pulse itself as the symbolic ‘rhythm of life’) and instants of pure material processuality...... a multilayered sense of time and space that is central to the sensory experience of Pulse Room as a whole. Pulse Room is, at the very same time, an anthropomorfized archive of a past intimacy and an all-encompassing immersive environment modulating continuously in real space-time....

  7. Five years use of Pulse Doppler RADAR-utechnology in debris-flows monitoring - experience at three test sites so far

    Science.gov (United States)

    Koschuch, Richard; Brauner, Michael; Hu, Kaiheng; Hübl, Johannes

    2016-04-01

    Automatic monitoring of alpine mass movement is a major challenge in dealing with natural hazards. The presented research project shows a new approach in measurment and alarming technology for water level changes an debris flow by using a high-frequency Pulse Doppler RADAR. The detection system was implemented on 3 places (2 in Tirol/Austria within the monitoring systems of the IAN/BOKU; 1 in Dongchuan/China within the monitoring systems of the IMHE/Chinese Academy of Science) in order to prove the applicability of the RADAR in monitoring torrential activities (e.g. debris-flows, mudflows, flash floods, etc.). The main objective is to illustrate the principles and the potential of an innovative RADAR system and its versatility as an automatic detection system for fast (> 1 km/h - 300 km/h) alpine mass movements of any kind. The high frequency RADAR device was already successfully tested for snow avalanches in Sedrun/Switzerland (Lussi et al., 2012), in Ischgl/Austria (Kogelnig et al., 2012). The experience and the data of the five year showed the enormous potential of the presented RADAR technology in use as an independent warning and monitoring system in the field of natural hazard. We have been able to measure water level changes, surface velocities and several debris flows and can compare this data with the other installed systems.

  8. Development of the 3MeV RFQ for the Compact Pulsed Hadron Source at Tsinghua University

    CERN Document Server

    Xing, Q Z; Cai, J C; Guan, X; Wang, X W; Wei, J; Xiong, Z F; Zhang, H Y; Billen, J H; Young, L M; Guan, W Q; He, Y; Li, J; Stovall, J

    2010-01-01

    We pre­sent, in this paper, the physics and me­chan­i­cal de­sign of a Radio Fre­quen­cy Quadrupole (RFQ) ac­cel­er­a­tor for the Com­pact Pulsed Hadron Source (CPHS) at Ts­inghua Uni­ver­si­ty. The 3-me­ter-long RFQ will ac­cel­er­ate pro­tons from 50 keV to 3 MeV at an RF fre­quen­cy of 325 MHz. In the physics de­sign we have pro­grammed the in­ter-vane volt­age as a func­tion of beam ve­loc­i­ty, to op­ti­mize the per­for­mance of the RFQ, by tai­lor­ing the cav­i­ty cross sec­tion and vane-tip ge­om­e­try as a func­tion of lon­gi­tu­di­nal po­si­tion while lim­it­ing the peak sur­face elec­tric field to 1.8 Kil­patrick. There will be no Medi­um-En­er­gy-Beam-Trans­port (MEBT) fol­low­ing the RFQ. The fo­cus­ing at the high en­er­gy end of the RFQ and at the en­trance of the DTL have been tai­lored to pro­vide con­tin­u­ous restor­ing forces in­de­pen­dent of the beam cur­rent. In sim­u­la­tions of the pro­ton beam in the RFQ, ...

  9. Local and regional sources of fine and coarse particulate matter based on traffic and background monitoring

    Science.gov (United States)

    Dimitriou, Konstantinos; Kassomenos, Pavlos

    2014-05-01

    The aim of this study was to identify local and exogenous sources affecting particulate matter (PM) levels in five major cities of Northern Europe namely: London, Paris, Hamburg, Copenhagen and Stockholm. Besides local emissions, PM profile at urban and suburban areas of the European Union (EU) is also influenced by regional PM sources due to atmospheric transport, thus geographical city distribution is of a great importance. At each city, PM10, PM2.5, NO2, SO2, CO and O3 air pollution data from two air pollution monitoring stations of the EU network were used. Different background characteristics of the selected two sampling sites at each city facilitated comparisons, providing a more exact analysis of PM sources. Four source apportionment methods: Pearson correlations among the levels of particulates and gaseous pollutants, characterisation of primal component analysis components, long-range transport analysis and extrapolation of PM size distribution ratios were applied. In general, fine (PM2.5) and coarse (PM10) particles were highly correlated, thus common sources are suggested. Combustion-originated gaseous pollutants (CO, NO2, SO2) were strongly associated to PM10 and PM2.5, primarily at areas severely affected by traffic. On the contrary, at background stations neighbouring important natural sources of particles or situated in suburban areas with rural background, natural emissions of aerosols were indicated. Series of daily PM2.5/PM10 ratios showed that minimum fraction values were detected during warm periods, due to higher volumes of airborne biogenic PM coarse, mainly at stations with important natural sources of particles in their vicinity. Hybrid single-particle Lagrangian integrated trajectory model was used, in order to extract 4-day backward air mass trajectories that arrived in the five cities which are under study during days with recorded PM10 exceedances. At all five cities, a significantly large fraction of those trajectories were classified

  10. Monitoring Land Based Sources of Pollution over Coral Reefs using VIIRS Ocean Color Products

    Science.gov (United States)

    Geiger, E.; Strong, A. E.; Eakin, C. M.; Wang, M.; Hernandez, W. J.; Cardona Maldonado, M. A.; De La Cour, J. L.; Liu, G.; Tirak, K.; Heron, S. F.; Skirving, W. J.; Armstrong, R.; Warner, R. A.

    2016-02-01

    NOAA's Coral Reef Watch (CRW) program and the NESDIS Ocean Color Team are developing new products to monitor land based sources of pollution (LBSP) over coral reef ecosystems using the Visible Infrared Imaging Radiometer Suite (VIIRS) onboard the S-NPP satellite. LBSP are a major threat to corals that can cause disease and mortality, disrupt critical ecological reef functions, and impede growth, reproduction, and larval settlement, among other impacts. From VIIRS, near-real-time satellite products of Chlorophyll-a, Kd(490), and sea surface temperature are being developed for three U.S. Coral Reef Task Force priority watershed sites - Ka'anapali (West Maui, Hawai'i), Faga'alu (American Samoa), and Guánica Bay (Puerto Rico). Background climatological levels of these parameters are being developed to construct anomaly products. Time-series data are being generated to monitor changes in water quality in near-real-time and provide information on historical variations, especially following significant rain events. A pilot calibration/validation field study of the VIIRS-based ocean color products is underway in Puerto Rico; we plan to expand this validation effort to the other two watersheds. Working with local resource managers, we have identified a focal area for product development and validation for each watershed and its associated local reefs. This poster will present preliminary results and identify a path forward to ensure marine resource managers understand and correctly use the new ocean color products, and to help NOAA CRW refine its satellite products to maximize their benefit to coral reef management. NOAA - National Oceanic and Atmospheric Administration NESDIS - NOAA/National Environmental Satellite, Data, and Information Service S-NPP - Suomi National Polar-orbiting Partnership

  11. THREE YEARS OF FERMI GBM EARTH OCCULTATION MONITORING: OBSERVATIONS OF HARD X-RAY/SOFT GAMMA-RAY SOURCES

    Energy Technology Data Exchange (ETDEWEB)

    Wilson-Hodge, Colleen A.; Jenke, Peter [ZP 12 Astrophysics Office, NASA Marshall Space Flight Center, Huntsville, AL 35812 (United States); Case, Gary L.; Cherry, Michael L.; Rodi, James [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803 (United States); Camero-Arranz, Ascension [Instituto de Ciencias del Espacio (IEEC-CSIC), Campus UAB, Torre C5, 2a planta, 08193 Barcelona (Spain); Chaplin, Vandiver; Bhat, Narayan; Briggs, Michael S.; Connaughton, Valerie; Preece, Robert [Physics Department, University of Alabama in Huntsville, Huntsville, AL 35899 (United States); Beklen, Elif [Physics Department, Suleyman Demirel University, 32260 Isparta (Turkey); Finger, Mark; Paciesas, William S. [Universities Space Research Association, Huntsville, AL 35805 (United States); Greiner, Jochen; Meegan, Charles A.; Von Kienlin, Andreas [Max-Planck Institut fuer Extraterrestische Physik, D-85748 Garching (Germany); Kippen, R. Marc [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2012-08-01

    The Gamma-ray Burst Monitor (GBM) on board Fermi has been providing continuous data to the astronomical community since 2008 August 12. In this paper, we present the results of the analysis of the first three years of these continuous data using the Earth occultation technique to monitor a catalog of 209 sources. From this catalog, we detect 99 sources, including 40 low-mass X-ray binary/neutron star systems, 31 high-mass X-ray binary/neutron star systems, 12 black hole binaries, 12 active galaxies, and 2 other sources, plus the Crab Nebula, and the Sun. Nine of these sources are detected in the 100-300 keV band, including seven black hole binaries, the active galaxy Cen A, and the Crab. The Crab and Cyg X-1 are also detected in the 300-500 keV band. GBM provides complementary data to other sky-monitors below 100 keV and is the only all-sky monitor above 100 keV. Up-to-date light curves for all of the catalog sources can be found online.

  12. Three years of Fermi GBM Earth Occultation Monitoring: Observations of Hard X-ray/Soft Gamma-Ray Sources

    CERN Document Server

    Wilson-Hodge, Colleen A; Cherry, Michael L; Rodi, James; Camero-Arranz, Ascension; Jenke, Peter; Chaplin, Vandiver; Beklen, Elif; Finger, Mark; Bhat, Narayan; Briggs, Michael S; Connaughton, Valerie; Greiner, Jochen; Kippen, R Marc; Meegan, Charles A; Paciesas, William S; Preece, Robert; von Kienlin, Andreas

    2012-01-01

    The Gamma ray Burst Monitor (GBM) on board Fermi has been providing continuous data to the astronomical community since 2008 August 12. In this paper we present the results of the analysis of the first three years of these continuous data using the Earth occultation technique to monitor a catalog of 209 sources. From this catalog, we detect 102 sources, including 41 low-mass X-ray binary/neutron star systems, 33 high-mass X-ray binary neutron star systems, 12 black hole binaries, 12 active galaxies, 2 other sources, plus the Crab Nebula, and the Sun. Nine of these sources are detected in the 100-300 keV band, including seven black-hole binaries, the active galaxy Cen A, and the Crab. The Crab and Cyg X-1 are also detected in the 300-500 keV band. GBM provides complementary data to other sky-monitors below 100 keV and is the only all-sky monitor above 100 keV. Up-to-date light curves for all of the catalog sources can be found at http://heastro.phys.lsu.edu/gbm/.

  13. Enhanced performance of an EUV light source (λ = 84 nm) using short-pulse excitation of a windowless dielectric barrier discharge in neon

    Science.gov (United States)

    Carman, R. J.; Kane, D. M.; Ward, B. K.

    2010-01-01

    The electrical and optical characteristics of a dielectric barrier discharge (DBD) based neon excimer lamp generating output in the extreme ultraviolet (EUV) spectral range (λ = 84 nm) have been investigated experimentally. We report a detailed comparison of lamp performance for both pulsed and sinusoidal voltage excitation waveforms, using otherwise identical operating conditions. The results show that pulsed voltage excitation yields a ~50% increase in the overall electrical to EUV conversion efficiency compared with sinusoidal waveforms, when operating in the pressure range 500-900 mbar. Pulsed operation allows greater control of parameters associated with the temporal evolution of the EUV pulse shapes (risetime, instantaneous peak power). The Ne DBD based source is also found to be highly monochromatic with respect to its spectral output from the second continuum band at λ ~ 84 nm (5 nm FWHM). This continuum band dominates the spectral emission over the wavelength range 30-550 nm. Lamp performance; as measured by the overall EUV output energy, electrical to EUV conversion efficiency and spectral purity at λ ~ 84 nm; improves with increasing gas pressure up to p = 900 mbar.

  14. Enhanced performance of an EUV light source ({lambda} = 84 nm) using short-pulse excitation of a windowless dielectric barrier discharge in neon

    Energy Technology Data Exchange (ETDEWEB)

    Carman, R J; Kane, D M; Ward, B K, E-mail: rcarman@science.mq.edu.a [Department of Physics and Engineering, Faculty of Science, Macquarie University, North Ryde, Sydney, NSW 2109 (Australia)

    2010-01-20

    The electrical and optical characteristics of a dielectric barrier discharge (DBD) based neon excimer lamp generating output in the extreme ultraviolet (EUV) spectral range ({lambda} = 84 nm) have been investigated experimentally. We report a detailed comparison of lamp performance for both pulsed and sinusoidal voltage excitation waveforms, using otherwise identical operating conditions. The results show that pulsed voltage excitation yields a {approx}50% increase in the overall electrical to EUV conversion efficiency compared with sinusoidal waveforms, when operating in the pressure range 500-900 mbar. Pulsed operation allows greater control of parameters associated with the temporal evolution of the EUV pulse shapes (risetime, instantaneous peak power). The Ne DBD based source is also found to be highly monochromatic with respect to its spectral output from the second continuum band at {lambda} {approx} 84 nm (5 nm FWHM). This continuum band dominates the spectral emission over the wavelength range 30-550 nm. Lamp performance; as measured by the overall EUV output energy, electrical to EUV conversion efficiency and spectral purity at {lambda} {approx} 84 nm; improves with increasing gas pressure up to p = 900 mbar.

  15. Multi-component machine monitoring and fault diagnosis using blind source separation and advanced vibration analysis

    Science.gov (United States)

    Mahvash Mohammadi, Ali

    In this dissertation, two approaches are studied for the case of bearing anomaly detection. One approach is to regard it as a blind source separation (cocktail party) problem and take advantage of statistical and mathematical methods developed for this purpose, primarily independent component analysis (ICA), to separate signals coming from different sources. The other approach is to avoid making the effort to 'separate' the signals and relate them to different components (sources) and instead make use of the specification and characteristics of vibration signals produced by the different components in normal and faulty conditions. In the first approach, a common difficulty with applying blind source separation techniques (or, in general any mathematical methods) to separation of vibration sources is that no standard measure exists to assess the quality of separation and validate the results. In fact, for an ideal assessment the true original signals produced by each component must be available as a prerequisite. This requires gathering signals from each component in strict isolation during operation in a lab environment which, if not impossible, is very costly and difficult. To alleviate this difficulty, a novel method is developed that presents the distribution of vibration energy with regard to the respective locations of vibration sources and sensors, and takes into consideration the mechanical attributes of the structure. This method uses some key concepts from statistical energy analysis (SEA) to support the fact that each sensor collects a different version of the oscillations produced in the system with respect to its location in the system. Therefore, by comparing the spectral signature of the vibration signals and making use of a priori knowledge of the spatial distribution of sensors and components, a schematic representation of the spectral signature of the vibration sources are obtained. This method is verified using a series of experiments with

  16. Pulsed lasers versus continuous light sources in capillary electrophoresis and fluorescence detection studies: Photodegradation pathways and models.

    Science.gov (United States)

    Boutonnet, Audrey; Morin, Arnaud; Petit, Pierre; Vicendo, Patricia; Poinsot, Véréna; Couderc, François

    2016-03-17

    Pulsed lasers are widely used in capillary electrophoresis (CE) studies to provide laser induced fluorescence (LIF) detection. Unfortunately pulsed lasers do not give linear calibration curves over a wide range of concentrations. While this does not prevent their use in CE/LIF studies, the non-linear behavior must be understood. Using 7-hydroxycoumarin (7-HC) (10-5000 nM), Tamra (10-5000 nM) and tryptophan (1-200 μM) as dyes, we observe that continuous lasers and LEDs result in linear calibration curves, while pulsed lasers give polynomial ones. The effect is seen with both visible light (530 nm) and with UV light (355 nm, 266 nm). In this work we point out the formation of byproducts induced by pulsed laser upon irradiation of 7-HC. Their separation by CE using two Zeta LIF detectors clearly shows that this process is related to the first laser detection. All of these photodegradation products can be identified by an ESI-/MS investigation and correspond to at least two 7HC dimers. By using the photodegradation model proposed by Heywood and Farnsworth (2010) and by taking into account the 7-HC results and the fact that in our system we do not have a constant concentration of fluorophore, it is possible to propose a new photochemical model of fluorescence in LIF detection. The model, like the experiment, shows that it is difficult to obtain linear quantitation curves with pulsed lasers while UV-LEDs used in continuous mode have this advantage. They are a good alternative to UV pulsed lasers. An application involving the separation and linear quantification of oligosaccharides labeled with 2-aminobezoic acid is presented using HILIC and LED (365 nm) induced fluorescence. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Pulsed lasers versus continuous light sources in capillary electrophoresis and fluorescence detection studies: Photodegradation pathways and models

    Energy Technology Data Exchange (ETDEWEB)

    Boutonnet, Audrey; Morin, Arnaud [Picometrics Technologies, 478 Rue de la Découverte, Labège France (France); Petit, Pierre [Institut de Mathématiques, Université de Toulouse, Université Paul Sabatier, Toulouse CEDEX 04 (France); Vicendo, Patricia; Poinsot, Véréna [Laboratoire des IMRCP, UMR 5623, Université de Toulouse, Université Paul Sabatier, Toulouse CEDEX 04 (France); Couderc, François, E-mail: couderc@chimie.ups-tlse.fr [Laboratoire des IMRCP, UMR 5623, Université de Toulouse, Université Paul Sabatier, Toulouse CEDEX 04 (France)

    2016-03-17

    Pulsed lasers are widely used in capillary electrophoresis (CE) studies to provide laser induced fluorescence (LIF) detection. Unfortunately pulsed lasers do not give linear calibration curves over a wide range of concentrations. While this does not prevent their use in CE/LIF studies, the non-linear behavior must be understood. Using 7-hydroxycoumarin (7-HC) (10–5000 nM), Tamra (10–5000 nM) and tryptophan (1–200 μM) as dyes, we observe that continuous lasers and LEDs result in linear calibration curves, while pulsed lasers give polynomial ones. The effect is seen with both visible light (530 nm) and with UV light (355 nm, 266 nm). In this work we point out the formation of byproducts induced by pulsed laser upon irradiation of 7-HC. Their separation by CE using two Zeta LIF detectors clearly shows that this process is related to the first laser detection. All of these photodegradation products can be identified by an ESI-/MS investigation and correspond to at least two 7HC dimers. By using the photodegradation model proposed by Heywood and Farnsworth (2010) and by taking into account the 7-HC results and the fact that in our system we do not have a constant concentration of fluorophore, it is possible to propose a new photochemical model of fluorescence in LIF detection. The model, like the experiment, shows that it is difficult to obtain linear quantitation curves with pulsed lasers while UV-LEDs used in continuous mode have this advantage. They are a good alternative to UV pulsed lasers. An application involving the separation and linear quantification of oligosaccharides labeled with 2-aminobezoic acid is presented using HILIC and LED (365 nm) induced fluorescence. - Highlights: • No linear calibration curves are obtained in CE/Pulsed-LIF detection. • Photodegradation and photodimerisation are responsible of this non linearity. • A mathematical model of this phenomenon is presented. • 7 hydroxycoumarin in CE/LIF is used to verify the

  18. CW/Pulsed H{sup −} ion beam generation with PKU Cs-free 2.45 GHz microwave driven ion source

    Energy Technology Data Exchange (ETDEWEB)

    Peng, S. X., E-mail: sxpeng@pku.edu.cn; Ren, H. T.; Xu, Y.; Zhang, T.; Zhang, J. F.; Zhao, J.; Guo, Z. Y. [State Key Laboratory of Nuclear Physics and Technology and Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing 100871, People' s Republic of China (China); Zhang, A. L. [University of Chinese Academy of Sciences, Beijing 100049, People' s Republic of China (China); Chen, J. E. [State Key Laboratory of Nuclear Physics and Technology and Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing 100871, People' s Republic of China (China); University of Chinese Academy of Sciences, Beijing 100049, People' s Republic of China (China)

    2015-04-08

    Circular accelerators used for positron emission tomography (PET, i.e. accelerator used for make radio isotopes) need several mA of CW H- ion beam for their routine operation. Other facilities, like Space Radio-Environment Simulate Assembly (SPRESA), require less than 10 mA pulsed mode H{sup −} beam. Caesium free negative hydrogen ion source is a good choice for those facilities because of its compact structure, easy operation and low cost. Up to now, there is no H{sup −} source able to produce very intense H{sup −} beams with important variation of the duty factor{sup [1]}. Recently, a new version of 2.45 GHz microwave H{sup −} ion source was designed at PKU, based on lessons learnt from the previous one. This non cesiated source is very compact thanks to its permanent magnet configuration. Special attention was paid on the design of the discharge chamber structure, electron dumping and extraction system. Source test to produce H{sup −} ion beams in pulsed and CW mode was carried out on PKU ion source test bench. In CW mode, a 10.8 mA/30keV H{sup −} beam with rms emittance about 0.16 π·mm·mrad has been obtained with only 500 W rf power. The power efficiency reaches 21 mA/kW. In pulsed mode with duty factor of 10% (100Hz/1ms), this compact source can easily deliver 20 mA H{sup −} ion beam at 35 keV with rms emittance about 0.2 π·mm·mrad when RF power is set at 2.2 kW (peak power). Several hour successive running operation in both modes and totaling more than 200 hours proves its high quality. The outside dimension of this new H{sup −} source body is ϕ116 mm × 124 mm, and the entire H{sup −} source infrastructure, including rf matching section, plasma chamber and extraction system, is ϕ310 × 180 mm. The high voltage region is limited with in a ϕ310 mm × 230 mm diagram. Details are given in this paper.

  19. Investigation of the effects of a thin dielectric layer on low-pressure hydrogen capacitive discharges driven by combined radio frequency and pulse power sources

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Jizhong; Fan, Yu; Zou, Ying; Wang, Dezhen [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Ministry of Education), School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China); Stirner, Thomas [Department of Electronic Engineering, University of Applied Sciences Deggendorf, Edlmairstr. 6-8, D-94469 Deggendorf (Germany)

    2013-11-15

    Negative hydrogen ion sources, for instance for fusion devices, currently attract considerable attention. To generate the precursors—highly rovibrationally excited hydrogen molecules—for negative hydrogen ions effectively by electron excitation, a thin dielectric layer is introduced to cover the surface of the electrically grounded electrode of two parallel metal plates in a low-pressure hydrogen capacitive discharge driven by combined rf and pulse power sources. To understand the characteristics of such discharges, particle-in-cell simulations are conducted to study the effects that the single dielectric layer would bring onto the discharges. The simulation results show that the dielectric layer leads to a much higher plasma density and a much larger production rate of highly vibrationally excited hydrogen molecules compared to discharges without the dielectric layer on the electrode. Further investigation indicates that the nonlinear oscillation of the electrons induced by the nanosecond-pulse continues until it is finally damped down and does not show any dependence on the pulse plateau-time, which is in stark contrast to the case without the dielectric layer present. The physical reason for this phenomenon is explored and explained.

  20. Experimental investigations on the influence of the photocathode laser pulse parameters on the electron bunch quality in an RF-photoelectron source

    Energy Technology Data Exchange (ETDEWEB)

    Haenel, Marc

    2010-07-15

    Free Electron Lasers based on the SASE principle like the European XFEL require electron bunches having peak currents of several kiloamperes as well as very low transverse emittance. While high peak currents can be generated using longitudinal bunch compression techniques, the transverse emittance must have values as low as 1mmmrad already at the source. The development of electron sources fulfilling these demanding specifications is the goal of the Photo Injector Test Facility (PITZ) in DESY, Zeuthen site. The key component of a photoinjector is the electron gun cavity where the electrons bunches are generated and immediately accelerated. The extraction of the electrons is based on the photoelectric effect of the cathode which requires a laser system having special capabilities. In the first part of the thesis, measurements are presented which were performed to investigate whether the laser and the laser transport system fulfill these requirements. The second part of the thesis is dedicated to simulations as well as experimental studies on the impact of the temporal and spatial parameters of the laser pulses on the electron bunch quality. This influence is possible because the response time of the Cs{sub 2}Te photocathode is short compared to the laser pulse duration. Based on these investigations, suggestions for improvements are given and tolerances for the laser pulse properties are defined. (orig.)