WorldWideScience

Sample records for beam loss localization

  1. Beam Loss in Linacs

    CERN Document Server

    Plum, M.A.

    2016-01-01

    Beam loss is a critical issue in high-intensity accelerators, and much effort is expended during both the design and operation phases to minimize the loss and to keep it to manageable levels. As new accelerators become ever more powerful, beam loss becomes even more critical. Linacs for H- ion beams, such as the one at the Oak Ridge Spallation Neutron Source, have many more loss mechanisms compared to H+ (proton) linacs, such as the one being designed for the European Spallation Neutron Source. Interesting H- beam loss mechanisms include residual gas stripping, H+ capture and acceleration, field stripping, black-body radiation and the recently discovered intra-beam stripping mechanism. Beam halo formation, and ion source or RF turn on/off transients, are examples of beam loss mechanisms that are common for both H+ and H- accelerators. Machine protection systems play an important role in limiting the beam loss.

  2. Overview of LHC Beam Loss Measurements

    CERN Document Server

    Dehning, B; Effinger, E; Emery, J; Fadakis, E; Holzer, E B; Jackson, S; Kruk, G; Kurfuerst, C; Marsili, A; Misiowiec, M; Nebot Del Busto, E; Nordt, A; Priebe, A; Roderick, C; Sapinski, M; Zamantzas, C; Grishin, V; Griesmayer, E

    2011-01-01

    The LHC beam loss monitoring system provides measurements with an update rate of 1 Hz and high time resolution data by event triggering. These informations are used for the initiation of beam aborts, fixed displays and the off line analysis. The analysis of fast and localized loss events resulted in the determination of its rate, duration, peak amplitudes, its scaling with intensity, number of bunches and beam energy. The calibration of the secondary shower beam loss signal in respect to the needed beam energy deposition to quench the magnet coil is addressed at 450GeV and 3.5T eV . The adjustment of collimators is checked my measuring the loss pattern and its variation in the collimation regions of the LHC. Loss pattern changes during a fill allow the observation of non typical fill parameters.

  3. Beam Dynamics and Beam Losses - Circular Machines

    CERN Document Server

    Kain, V

    2016-01-01

    A basic introduction to transverse and longitudinal beam dynamics as well as the most relevant beam loss mechanisms in circular machines will be presented in this lecture. This lecture is intended for physicists and engineers with little or no knowledge of this subject.

  4. Detection of Equipment Faults Before Beam Loss

    CERN Document Server

    Galambos, J.

    2016-01-01

    High-power hadron accelerators have strict limits on fractional beam loss. In principle, once a high-quality beam is set up in an acceptable state, beam loss should remain steady. However, in practice, there are many trips in operational machines, owing to excessive beam loss. This paper deals with monitoring equipment health to identify precursor signals that indicate an issue with equipment that will lead to unacceptable beam loss. To this end, a variety of equipment and beam signal measurements are described. In particular, several operational examples from the Spallation Neutron Source (SNS) of deteriorating equipment functionality leading to beam loss are reported.

  5. Beam Loss Monitors at LHC

    CERN Document Server

    Dehning, B.

    2016-01-01

    One of the main functions of the LHC beam loss measurement system is the protection of equipment against damage caused by impacting particles creating secondary showers and their energy dissipation in the matter. Reliability requirements are scaled according to the acceptable consequences and the frequency of particle impact events on equipment. Increasing reliability often leads to more complex systems. The downside of complexity is a reduction of availability; therefore, an optimum has to be found for these conflicting requirements. A detailed review of selected concepts and solutions for the LHC system will be given to show approaches used in various parts of the system from the sensors, signal processing, and software implementations to the requirements for operation and documentation.

  6. Beam Cooling with ionisation losses

    CERN Document Server

    Rubbia, Carlo; Kadi, Y; Vlachoudis, V

    2006-01-01

    A novel type of particle "cooling", called Ionization Cooling, is applicable to slow (v of the order of 0.1c) ions stored in a small ring. The many traversals through a thin foil enhance the nuclear reaction probability, in a steady configuration in which ionisation losses are recovered at each turn by a RF-cavity. For a uniform target "foil" the longitudinal momentum spread diverges exponentially since faster (slower) particles ionise less (more) than the average. In order to "cool" also longitudinally, a chromaticity has to be introduced with a wedge shaped "foil". Multiple scattering and straggling are then "cooled" in all three dimensions, with a method similar to the one of synchrotron cooling, but valid for low energy ions. Particles then stably circulate in the beam indefinitely, until they undergo for instance nuclear processes in the thin target foil. This new method is under consideration for the nuclear production of a few MeV/A ion beams. Simple reactions, for instance Li 7 + D Li 8 + p, are more ...

  7. Beam Loss and Beam Shape at the LHC Collimators

    CERN Document Server

    Burkart, Florian

    In this master thesis the beam loss and the beam shape at the LHC collimators was measured, analysed, presented and discussed. Beginning with a short introduction of the LHC, the experiments, the supercon- ducting magnet system, the basics on linear beam dynamics and a describtion of the LHC collimation system are given. This is followed by the presentation of the performance of the LHC collimation sys- tem during 2011. A method to convert the Beam Loss Monitor signal in Gy/s to a proton beam loss rate will be introduced. Also the beam lifetime during the proton physics runs in 2011 will be presented and discussed. Finally, the shape of the LHC beams is analysed by using data obtained by scraping the beam at the LHC primary collimators.

  8. Booster gold beam injection efficiency and beam loss

    International Nuclear Information System (INIS)

    Zhang, S.Y.; Ahrens, L.A.

    1998-01-01

    The Relativistic Heavy Ion Collider (RHIC) at the BNL requires the AGS to provide Gold beam with the intensity of 10 9 ions per bunch. Over the years, the Tandem Van de Graaff has provided steadily increasing intensity of gold ion beams to the AGS Booster. However, the gold beam injection efficiency at the Booster has been found to decrease with the rising intensity of injected beams. As the result, for Tandem beams of the highest intensity, the Booster late intensity is lower than with slightly lower intensity Tandem beam. In this article, the authors present two experiments associated with the Booster injection efficiency and beam intensity. One experiment looks at the Booster injection efficiency by adjusting the Tandem beam intensity, and another looks at the beam life time while scraping the beam in the Booster. The studies suggest that the gold beam injection efficiency at the AGS Booster is related to the beam loss in the ring, rather than the intensity of injected beam or circulating beam. A close look at the effect of the lost gold ion at the Booster injection leads to the prediction that the lost gold ion creates large number of positive ions, and even larger number of electrons. The lost gold beam is also expected to create large numbers of neutral particles. In 1998 heavy ion run, the production of positive ions and electrons due to the lost gold beam has been observed. Also the high vacuum pressure due to the beam loss, presumably because of the neutral particles it created, has been measured. These results will be reported elsewhere

  9. Cryogenic Beam Loss Monitoring for the LHC

    CERN Document Server

    Kurfuerst, C; Sapinski, M

    A Beam Loss Monitoring (BLM) system was installed on the outside surface of the LHC magnet cryostats to protect the accelerator equipment from beam losses. The protection is achieved by extracting the beam from the ring in case thresholds imposed on measured radiation levels are exceeded. Close to the interaction regions of the LHC, the present BLM system is sensitive to particle showers generated in the interaction region of the two beams. In the future, with beams of higher energy and brightness resulting in higher luminosity, distinguishing between these interaction products and possible quench-provoking beam losses from the primary proton beams will be challenging. The particle showers measured by the present BLM configuration are partly shielded by the cryostat and the iron yoke of the magnets. The system can hence be optimised by locating beam loss monitors as close as possible to the protected element, i. e. the superconducting coils, inside the cold mass of the magnets in superfluid helium at 1.9 K. T...

  10. Beam Loss Monitoring for LHC Machine Protection

    Science.gov (United States)

    Holzer, Eva Barbara; Dehning, Bernd; Effnger, Ewald; Emery, Jonathan; Grishin, Viatcheslav; Hajdu, Csaba; Jackson, Stephen; Kurfuerst, Christoph; Marsili, Aurelien; Misiowiec, Marek; Nagel, Markus; Busto, Eduardo Nebot Del; Nordt, Annika; Roderick, Chris; Sapinski, Mariusz; Zamantzas, Christos

    The energy stored in the nominal LHC beams is two times 362 MJ, 100 times the energy of the Tevatron. As little as 1 mJ/cm3 deposited energy quenches a magnet at 7 TeV and 1 J/cm3 causes magnet damage. The beam dumps are the only places to safely dispose of this beam. One of the key systems for machine protection is the beam loss monitoring (BLM) system. About 3600 ionization chambers are installed at likely or critical loss locations around the LHC ring. The losses are integrated in 12 time intervals ranging from 40 μs to 84 s and compared to threshold values defined in 32 energy ranges. A beam abort is requested when potentially dangerous losses are detected or when any of the numerous internal system validation tests fails. In addition, loss data are used for machine set-up and operational verifications. The collimation system for example uses the loss data for set-up and regular performance verification. Commissioning and operational experience of the BLM are presented: The machine protection functionality of the BLM system has been fully reliable; the LHC availability has not been compromised by false beam aborts.

  11. RHIC Beam Loss Monitor System Initial Operation

    International Nuclear Information System (INIS)

    Witkover, R. L.; Michnoff, R. J.; Geller, J. M.

    1999-01-01

    The RHIC Beam Loss Monitor (BLM) System is designed to prevent beam loss quenching of the superconducting magnets, and acquire loss data. Four hundred ion chambers are located around the rings to detect losses. The required 8-decade range in signal current is compressed using an RC pre-integrator ahead of a low current amplifier. A beam abort may be triggered if fast or slow losses exceed programmable threshold levels. A micro-controller based VME module sets references and gains and reads trip status for up to 64 channels. Results obtained with the detectors in the RHIC Sextant Test and the prototype electronics in the AGS-to-RHIC (AtR) transfer line are presented along with the present status of the system

  12. Measuring beam losses in the THI project

    International Nuclear Information System (INIS)

    David, L.; Duneau, P.; Lecorche, E.; Lermine, P.; Lemaitre, E.; Ulrich, M.

    1997-01-01

    The goal of the THI project (High Intensity Transport) is to upgrade the GANIL facilities by increasing the beam by a factor of 15, at least for light ions. This higher intensity is required by the radioactive beam facility SPIRAL starting in September 1997, to generate the new nuclear species in the solid target-source (ISOL method). For the control system, the most important issues are now to tune the accelerators while minimizing the beam losses at each stage of acceleration and when not possible, to have a fast beam loss detection signal. This system is composed of probes which deliver a signal to stop the beam when there's too much intensity lost and when not, a logarithmic value of the beam intensity. These probes are linked to a front end VME crate on the network, and in the control room, on the workstations, a graphical user interface program displays the beam variations using logarithmic scales. This program is also used to center the beam while injecting in or ejecting from the main cyclotrons by tuning the steerers, the magnetic elements inside, and the electrostatic deflector to be able to separate and extract the last beam turn. (author)

  13. Beam losses in heavy ion drivers

    CERN Document Server

    Mustafin, E R; Hofmann, I; Spiller, P J

    2002-01-01

    While beam loss issues have hardly been considered in detail for heavy ion fusion scenarios, recent heavy ion machine developments in different labs (European Organization for Nuclear Research (CERN), Gesellschaft fur Schwerionenforschung (GSI), Institute for Theoretical and Experimental Physics (ITEP), Relativistic Heavy-Ion Collider (RHIC)) have shown the great importance of beam current limitations due to ion losses. Two aspects of beam losses in heavy ion accelerators are theoretically considered: (1) secondary neutron production due to lost ions, and (2) vacuum pressure instability due to charge exchange losses. Calculations are compared and found to be in good agreement with measured data. The application to a Heavy-Ion Driven Inertial Fusion (HIDIF) scenario is discussed. 12 Refs.

  14. Beam loss detection system in the arcs of the LHC

    Science.gov (United States)

    Arauzo, A.; Bovet, C.

    2000-11-01

    Over the whole circumference of the LHC, Beam Loss Monitors (BLM) will be needed for a continuous surveillance of fast and slow beam losses. In this paper, the location of the BLMs set outside the magnet cryostats in the arcs is proposed. In order to know the number of protons lost on the beam screen, the sensitivity of each BLM has been computed using the program GEANT 3.21, which generates the shower inside the cryostat. The material and the magnetic fields have been described thoroughly in 3-D and the simulation results show the best locations for 6 BLMs needed around each quadrupole. The number of minimum ionizing particles received for each lost proton serves to define local thresholds to dump the beam when the losses are menacing to quench a magnet.

  15. Beam loss detection system in the arcs of the LHC

    International Nuclear Information System (INIS)

    Arauzo, A.; Bovet, C.

    2000-01-01

    Over the whole circumference of the LHC, Beam Loss Monitors (BLM) will be needed for a continuous surveillance of fast and slow beam losses. In this paper, the location of the BLMs set outside the magnet cryostats in the arcs is proposed. In order to know the number of protons lost on the beam screen, the sensitivity of each BLM has been computed using the program GEANT 3.21, which generates the shower inside the cryostat. The material and the magnetic fields have been described thoroughly in 3-D and the simulation results show the best locations for 6 BLMs needed around each quadrupole. The number of minimum ionizing particles received for each lost proton serves to define local thresholds to dump the beam when the losses are menacing to quench a magnet

  16. Beam Loss Detection at Radiation Source ELBE

    CERN Document Server

    Michel, P; Schurig, R; Langenhagen, H

    2003-01-01

    The Rossendorf superconducting Electron Linac of high Brilliance and low Emittance (ELBE) delivers an 40 MeV, 1 mA cw-beam for different applications such as bremsstrahlung production, electron channelling, free-electron lasers or secondary particle beam generation. In this energy region in case of collisions of the electron beam with the pipe nearly all beam power will be deposited into the pipe material. Therefore a reliable beam loss monitoring is essential for machine protection at ELBE. Different systems basing on photo multipliers, compton diodes and long ionization chambers were studied. The pros and cons of the different systems will be discussed. Ionization chambers based on air-isolated RF cables installed some cm away parallel to the beam line turned out to be the optimal solution. The beam shut-off threshold was adjusted to 1 μC integral charge loss during a 100 ms time interval. Due to the favourable geometry the monitor sensitivity varies less than ±50% along the beam line (di...

  17. Simulation and Measurements of Beam Losses on LHC Collimators During Beam Abort Failures

    CERN Document Server

    Lari, L; Bruce, R; Goddard, B; Redaelli, S; Salvachua, B; Valentino, G; Faus-Golfe, A

    2013-01-01

    One of the main purposes of tracking simulations for collimation studies is to produce loss maps along the LHC ring, in order to identify the level of local beam losses during nominal and abnormal operation scenarios. The SixTrack program is the standard tracking tool used at CERN to perform these studies. Recently, it was expanded in order to evaluate the proton load on different collimators in case of fast beam failures. Simulations are compared with beam measurements at 4 TeV. Combined failures are assumed which provide worst-case scenarios of the load on tungsten tertiary collimators.

  18. PDX neutral-beam reionization losses

    International Nuclear Information System (INIS)

    Kugel, H.W.; Dylla, H.F.; Eubank, H.P.; Kozub, T.A.; Moore, R.; Schilling, G.; Stewart, L.D.; von Halle, A.; Williams, M.D.

    1982-02-01

    Reionization losses for 1.5 MW H 0 and 2 MW D 0 neutral beams injected into the PDX tokamak were studied using pressure gauges, photo-transistors, thermocouples, surface shielding, and surface sample analysis. Considerable outgassing of conventionally prepared 304SS ducts occurred during initial injections and gradually decreased with the cumulative absorption of beam power. Reionization power losses are presently about 5% in the ducts and about 12% total for a beamline including the duct. Present duct pressures are attributed primarily to gas from the ion source and neutralizer with much smaller contributions from residual wall desorption. Physical mechanisms for the observed duct outgassing are discussed

  19. RHIC beam loss monitor system design

    International Nuclear Information System (INIS)

    Witkover, R.; Zitvogel, E.; Michnoff, R.

    1997-01-01

    The Beam Loss Monitor (BLM) System is designed to prevent the quenching of RHIC magnets due to beam loss, provide quantitative loss data, and the loss history in the event of a beam abort. The system uses 400 ion chambers of a modified Tevatron design. To satisfy fast (single turn) and slow (100 msec) loss beam criteria and provide sensitivity for studies measurements, a range of over 8 decades is needed. An RC pre-integrator reduces the dynamic range for a low current amplifier. This is digitized for data logging. The output is also applied to an analog multiplier which compensates the energy dependence, extending the range of the abort comparators. High and low pass filters separate the signal to dual comparators with independent programmable trip levels. Up to 64 channels, on 8 VME boards, are controlled by a micro-controller based VME module, decoupling it from the front-end computer (FEC) for real-time operation. Results with the detectors in the RHIC Sextant Test and the electronics in the AGS-to-RHIC (AtR) transfer line will be presented

  20. Beam losses monitor for superconducting accelerators

    International Nuclear Information System (INIS)

    Kurochkin, I.A.; Lapitskij, S.N.; Mokhov, N.V.; Seleznev, V.S.

    1991-01-01

    A special beam losses monitor (BLM) for SC accelerators -colliders as an integral part od SC magnet (quadrupole or/and corrector) design is proposed. The main BLM parameters calculated under the real UNK and SSC conditions are presented in comparison with the traditional BLM ones which is planned to be used at SSC now. 9 refs.; 4 figs.; 2 tabs

  1. The LEP RF Trip and Beam Loss Diagnostics System

    CERN Document Server

    Arnaudon, L; Beetham, G; Ciapala, Edmond; Juillard, J C; Olsen, R

    2002-01-01

    During the last years of operation the number of operationally independent RF stations distributed around LEP reached a total of 40. A serious difficulty when running at high energy and high beam intensities was to establish cause and effect in beam loss situations, where the trip of any single RF station would result in beam loss, rapidly producing further multiple RF station trips. For the last year of operation a fast post-mortem diagnostics system was developed to allow precise time-stamping of RF unit trips and beam intensity changes. The system was based on eight local DSP controlled fast acquisition and event recording units, one in each RF sector, connected to critical RF control signals and fast beam intensity monitors and synchronised by GPS. The acquisition units were armed and synchronised at the start of each fill. At the end of the fill the local time-stamped RF trip and beam intensity change history tables were recovered, events ordered and the results stored in a database for subsequent analys...

  2. AIP Diffraction measurements using the LHC Beam Loss Monitoring System

    CERN Document Server

    Kalliokoski, Matti

    2017-01-01

    The Beam Loss Monitoring (BLM) system of the Large Hadron Collider protects the machine from beam induced damage by measuring the absorbed dose rates of beam losses, and by triggering beam dump if the rates increase above the allowed threshold limits. Although the detection time scales are optimized for multi-turn losses, information on fast losses can be recovered from the loss data. In this paper, methods in using the BLM system in di ff raction studies are discussed.

  3. Diffraction measurements using the LHC Beam Loss Monitoring System

    Science.gov (United States)

    Kalliokoski, Matti

    2017-03-01

    The Beam Loss Monitoring (BLM) system of the Large Hadron Collider protects the machine from beam induced damage by measuring the absorbed dose rates of beam losses, and by triggering beam dump if the rates increase above the allowed threshold limits. Although the detection time scales are optimized for multi-turn losses, information on fast losses can be recovered from the loss data. In this paper, methods in using the BLM system in diffraction studies are discussed.

  4. The AGS Booster beam loss monitor system

    International Nuclear Information System (INIS)

    Beadle, E.R.; Bennett, G.W.; Witkover, R.L.

    1991-01-01

    A beam loss monitor system has been developed for the Brookhaven National Laboratory Booster accelerator, and is designed for use with intensities of up to 1.5 x 10 13 protons and carbon to gold ions at 50-3 x 10 9 ions per pulse. This system is a significant advance over the present AGS system by improving the sensitivity, dynamic range, and data acquisition. In addition to the large dynamic range achievable, it is adaptively shifted when high losses are detected. The system uses up to 80 argon filled ion chambers as detectors, as well as newly designed electronics for processing and digitizing detector outputs. The hardware simultaneously integrates each detector output, interfaces to the beam interrupt systems, and digitizes all 80 channels to 21 bits at 170 KHz. This paper discuses the design, construction, and operation of the system. 4 refs., 2 figs

  5. Preservation of beam loss induced quenches, beam lifetime and beam loss measurements with the HERA-p beam-loss-monitor system

    International Nuclear Information System (INIS)

    Wittenburg, K.

    1994-01-01

    The beam-loss-monitors (BLMs) in the HERA-Proton-ring (HERAp) must fulfil the following requirements: They have to measure losses sensitive and fast enough to prevent the superconducting magnets from beam loss induced quenching; the dynamic range of the monitors must exceed several decades in order to measure losses during beam lifetimes of hundreds of hours as well as the much stronger losses that may quench superconducting magnets; they have to be insensitive to the synchrotron radiation of the adjacent electron-ring (HERAe); and their radiation hardness must allow a monitor-lifetime of a few years of HERA operation. These requirements are well satisfied by the HERAp-BLM-System. (orig.)

  6. Characteristics of possible beam losses in superconducting cyclotron

    International Nuclear Information System (INIS)

    Pradhan, J.; Paul, Santanu; Debnath, Jayanta; Dutta, Atanu; Bhunia, Uttam; Naser, Md. Zamal Abdul; Singh, Vinay; Agrawal, Ankur; Dey, Malay Kanti

    2015-01-01

    In a compact superconducting cyclotron large coherent oscillation and off-centering of the beam may cause large amount of beam loss. The off-centered beam may hit the beam chamber wall prohibiting extraction of the beam. Or it may hit the RF liner surfaces due to vertical blow-up across various resonances during acceleration. The vertical shift of beam caused by the mis-alignment gradually moves the beam out of geometrical median plane eventually leading to internal beam losses. The loss of isochronisms results the reduction of beam intensity depending on the particle phase history. Small field perturbations generated by trim coils have been used to identify the beam loss mechanisms in the superconducting cyclotron at out centre. Besides, the beam loss due to interaction of accelerating ions with residual gases is also discussed. The beam profile obtained from differential and three finger probes gives a clear insight of the loss-mechanism. The paper describes different beam losses observed in the cyclotron with corresponding beam profiles under different field perturbations, Special emphasis is given on characteristics features of beam-current profile to identify the cause of beam loss. (author)

  7. Beam loss monitor system for machine protection

    CERN Document Server

    Dehning, B

    2005-01-01

    Most beam loss monitoring systems are based on the detection of secondary shower particles which depose their energy in the accelerator equipment and finally also in the monitoring detector. To allow an efficient protection of the equipment, the likely loss locations have to be identified by tracking simulations or by using low intensity beams. If superconducting magnets are used for the beam guiding system, not only a damage protection is required but also quench preventions. The quench levels for high field magnets are several orders of magnitude below the damage levels. To keep the operational efficiency high under such circumstances, the calibration factor between the energy deposition in the coils and the energy deposition in the detectors has to be accurately known. To allow a reliable damage protection and quench prevention, the mean time between failures should be high. If in such failsafe system the number of monitors is numerous, the false dump probability has to be kept low to keep a high operation...

  8. Cryogenic beam loss monitoring for the LHC

    International Nuclear Information System (INIS)

    Kurfürst, C.

    2013-01-01

    A Beam Loss Monitoring (BLM) system was installed on the outside surface of the LHC magnet cryostats to protect the accelerator equipment from beam losses. The protection is achieved by extracting the beam from the ring in case thresholds imposed on measured radiation levels are exceeded. Close to the interaction regions of the LHC, the present BLM system is sensitive to particle showers generated in the interaction region of the two beams. In the future, with beams of higher energy and brightness resulting in higher luminosity, distinguishing between these interaction products and possible quench-provoking beam losses from the primary proton beams will be challenging. The particle showers measured by the present BLM configuration are partly shielded by the cryostat and the iron yoke of the magnets. The system can hence be optimised by locating beam loss monitors as close as possible to the protected element, i. e. the superconducting coils, inside the cold mass of the magnets in superfluid helium at 1.9 K. The advantage is that the dose measured by the Cryogenic Beam Loss Monitor (CryoBLM) would more precisely correspond to the dose deposited in the superconducting coil. The main challenges of this placement are the low temperature of 1.9 K and the integrated dose of 2 MGy in 20 years. Furthermore the CryoBLM should work in a magnetic field of 2 T and at a pressure of 1.1 bar, withstanding a fast pressure rise up to 20 bar in case of a magnet quench. The detector response should be linear between 0.1 and 10 mGy/s and faster than 1 ms. Once the detectors are installed in the LHC magnets, no access will be possible. Hence the detectors need to be available, reliable and stable for 20 years. Following intense research it became clear that no existing technology was proven to work in such conditions. The candidates under investigation in this work are diamond and silicon detectors and an ionisation chamber, using the liquid helium itself as particle detection medium

  9. Anomaly Detection for Beam Loss Maps in the Large Hadron Collider

    Science.gov (United States)

    Valentino, Gianluca; Bruce, Roderik; Redaelli, Stefano; Rossi, Roberto; Theodoropoulos, Panagiotis; Jaster-Merz, Sonja

    2017-07-01

    In the LHC, beam loss maps are used to validate collimator settings for cleaning and machine protection. This is done by monitoring the loss distribution in the ring during infrequent controlled loss map campaigns, as well as in standard operation. Due to the complexity of the system, consisting of more than 50 collimators per beam, it is difficult to identify small changes in the collimation hierarchy, which may be due to setting errors or beam orbit drifts with such methods. A technique based on Principal Component Analysis and Local Outlier Factor is presented to detect anomalies in the loss maps and therefore provide an automatic check of the collimation hierarchy.

  10. Anomaly Detection for Beam Loss Maps in the Large Hadron Collider

    International Nuclear Information System (INIS)

    Valentino, Gianluca; Bruce, Roderik; Redaelli, Stefano; Rossi, Roberto; Theodoropoulos, Panagiotis; Jaster-Merz, Sonja

    2017-01-01

    In the LHC, beam loss maps are used to validate collimator settings for cleaning and machine protection. This is done by monitoring the loss distribution in the ring during infrequent controlled loss map campaigns, as well as in standard operation. Due to the complexity of the system, consisting of more than 50 collimators per beam, it is difficult to identify small changes in the collimation hierarchy, which may be due to setting errors or beam orbit drifts with such methods. A technique based on Principal Component Analysis and Local Outlier Factor is presented to detect anomalies in the loss maps and therefore provide an automatic check of the collimation hierarchy. (paper)

  11. Luminosity Loss due to Beam Distortion and the Beam-Beam Instability

    CERN Document Server

    Wu, Juhao; Raubenheimer, Tor O; Seryi, Andrei; Sramek, Christopher K

    2005-01-01

    In a linear collider, sources of emittance dilution such as transverse wakefields or dispersive errors will couple the vertical phase space to the longitudinal position within the beam (the so-called ‘banana effect'). When the Intersection Point (IP) disruption parameter is large, these beam distortions will be amplified by a single bunch kink instability which will lead to luminosity loss. We study this phenomena both analytically using linear theory and via numerical simulation. In particular, we examine the dependence of the luminosity loss on the wavelength of the beam distortions and the disruption parameter. This analysis may prove useful when optimizing the vertical disruption parameter for luminosity operation with given beam distortions.

  12. Mitigation of numerical noise for beam loss simulations

    CERN Document Server

    Kesting, Frederik

    2017-01-01

    Numerical noise emerges in self-consistent simulations of charged particles, and its mitigation is investigated since the first numerical studies in plasma physics. In accelerator physics, recent studies find an artificial diffusion of the particle beam due to numerical noise in particle-in-cell tracking, which is of particular importance for high intensity machines with a long storage time, as the SIS100 at FAIR or in context of the LIU upgrade at CERN. In beam loss simulations for these projects artificial effects must be distinguished from physical beam loss. Therefore, it is important to relate artificial diffusion to artificial beam loss, and to choose simulation parameters such that physical beam loss is well resolved. As a practical tool, we therefore suggest a scaling law to find optimal simulation parameters for a given maximum percentage of acceptable artificial beam loss.

  13. Measurement of Beam Loss at the Australian Synchrotron

    CERN Document Server

    Holzer, EB; Kastriotou, M; Boland, MJ; Jackson, PD; Rasool, RP; Schmidt, J; Welsch, CP

    2014-01-01

    The unprecedented requirements that new machines are setting on their diagnostic systems is leading to the development of new generation of devices with large dynamic range, sensitivity and time resolution. Beam loss detection is particularly challenging due to the large extension of new facilities that need to be covered with localized detector. Candidates to mitigate this problem consist of systems in which the sensitive part of the radiation detectors can be extended over long distance of beam lines. In this document we study the feasibility of a BLM system based on optical fiber as an active detector for an electron storage ring. The Australian Synchrotron (AS) comprises a 216m ring that stores electrons up to 3GeV. The Accelerator has recently claimed the world record ultra low transverse emittance (below pm rad) and its surroundings are rich in synchrotron radiation. Therefore, the AS provides beam conditions very similar to those expected in the CLIC/ILC damping rings. A qualitative benchmark of beam l...

  14. Measurements of Beam Ion Loss from the Compact Helical System

    International Nuclear Information System (INIS)

    Darrow, D.S.; Isobe, M.; Kondo, Takashi; Sasao, M.

    2010-01-01

    Beam ion loss from the Compact Helical System (CHS) has been measured with a scintillator-type probe. The total loss to the probe, and the pitch angle and gyroradius distributions of that loss, have been measured as various plasma parameters were scanned. Three classes of beam ion loss were observed at the probe position: passing ions with pitch angles within 10o of those of transition orbits, ions on transition orbits, and ions on trapped orbits, typically 15o or more from transition orbits. Some orbit calculations in this geometry have been performed in order to understand the characteristics of the loss. Simulation of the detector signal based upon the following of orbits from realistic beam deposition profiles is not able to reproduce the pitch angle distribution of the losses measured. Consequently it is inferred that internal plasma processes, whether magnetohydrodynamic modes, radial electric fields, or plasma turbulence, move previously confined beam ions to transition orbits, resulting in their loss.

  15. Anomolous, intensity dependent losses in Au(32+) beams

    International Nuclear Information System (INIS)

    Blaskiewicz, M.; Ahrens, L.; Calvani, H.

    1997-01-01

    The AGS Booster is a rapid cycling proton and heavy ion synchrotron. Anomolous, intensity dependent losses in Au(32+) beams have been observed in the AGS Booster. No collective signal is expected, or observed, but increasing the number of injected ions decreases the beam lifetime. The loss rates for Au(32+) are compared with those for Au(15+)

  16. Beam Loss Patterns at the LHC Collimators Measurements & Simulations

    CERN Document Server

    Böhlen, Till Tobias

    2008-01-01

    The Beam Loss Monitoring (BLM) system of the Large Hadron Collider (LHC) detects particle losses of circulating beams and initiates an emergency extraction of the beam in case that the BLM thresholds are exceeded. This protection is required as energy deposition in the accelerator equipment due to secondary shower particles can reach critical levels; causing damage to the beam-line components and quenches of superconducting magnets. Robust and movable beam line elements, so-called collimators, are the aperture limitations of the LHC. Consequently, they are exposed to the excess of lost beam particles and their showers. Proton loss patterns at LHC collimators have to be determined to interpret the signal of the BLM detectors and to set adequate BLM thresholds for the protection of collimators and other equipment in case of unacceptably increased loss rates. The first part of this work investigates the agreement of BLM detector measurements with simulations for an LHC-like collimation setup. The setup consists ...

  17. LHC Beam Loss Monitoring System Verification Applications

    CERN Document Server

    Dehning, B; Zamantzas, C; Jackson, S

    2011-01-01

    The LHC Beam Loss Mon­i­tor­ing (BLM) sys­tem is one of the most com­plex in­stru­men­ta­tion sys­tems de­ployed in the LHC. In ad­di­tion to protecting the col­lid­er, the sys­tem also needs to pro­vide a means of di­ag­nos­ing ma­chine faults and de­liv­er a feed­back of loss­es to the control room as well as to sev­er­al sys­tems for their setup and analysis. It has to trans­mit and pro­cess sig­nals from al­most 4’000 mon­i­tors, and has near­ly 3 mil­lion con­fig­urable pa­ram­e­ters. The system was de­signed with re­li­a­bil­i­ty and avail­abil­i­ty in mind. The spec­i­fied op­er­a­tion and the fail-safe­ty stan­dards must be guar­an­teed for the sys­tem to per­form its func­tion in pre­vent­ing su­per­con­duc­tive mag­net de­struc­tion caused by par­ti­cle flux. Main­tain­ing the ex­pect­ed re­li­a­bil­i­ty re­quires ex­ten­sive test­ing and ver­i­fi­ca­tion. In this paper we re­port our most re­cent ad­di­t...

  18. Accidental Beam Losses and Protection in the LHC

    International Nuclear Information System (INIS)

    Schmidt, R.; Wenninger, J.

    2005-01-01

    At top energy (proton momentum 7 TeV/c) with nominal beam parameters, each of the two LHC proton beams has a stored energy of 350 MJ threatening to damage accelerator equipment in case of accidental beam loss. It is essential that the beams are properly extracted onto the dump blocks in case of failure since these are the only elements that can withstand full beam impact. Although the energy stored in the beams at injection (450 GeV/c) is about 15 times smaller compared to top energy, the beams must still be properly extracted in case of large accidental beam losses. Failures must be detected at a sufficiently early stage and initiate a beam dump. Quenches and power converter failures will be detected by monitoring the correct functioning of the hardware systems. In addition, safe operation throughout the cycle requires the use of beam loss monitors, collimators and absorbers. Ideas of detection of fast beam current decay, monitoring of fast beam position changes and monitoring of fast magnet current changes are discussed, to provide the required redundancy for machine protection

  19. Accidental Beam Losses and Protection in the LHC

    Science.gov (United States)

    Schmidt, R.; Working Group On Machine Protection

    2005-06-01

    At top energy (proton momentum 7 TeV/c) with nominal beam parameters, each of the two LHC proton beams has a stored energy of 350 MJ threatening to damage accelerator equipment in case of accidental beam loss. It is essential that the beams are properly extracted onto the dump blocks in case of failure since these are the only elements that can withstand full beam impact. Although the energy stored in the beams at injection (450 GeV/c) is about 15 times smaller compared to top energy, the beams must still be properly extracted in case of large accidental beam losses. Failures must be detected at a sufficiently early stage and initiate a beam dump. Quenches and power converter failures will be detected by monitoring the correct functioning of the hardware systems. In addition, safe operation throughout the cycle requires the use of beam loss monitors, collimators and absorbers. Ideas of detection of fast beam current decay, monitoring of fast beam position changes and monitoring of fast magnet current changes are discussed, to provide the required redundancy for machine protection.

  20. Configuration of the Beam Loss Monitors for the LHC arcs

    CERN Document Server

    Arauzo-Garcia, A

    2000-01-01

    A revised configuration for a beam loss detection system is given for the arcs of the LHC. The last modifications of the LHC arc layout have been taken into account, LHC optics version 6.2. A set of 6 Loss Detectors will be placed outside the cryostat around each short straight section. Quench alarm thresholds are estimated for each detector in all possible LHC arc layout configurations. Threshold values are proposed for top and injection energy beam loss.

  1. Comparative study of beam losses and heat loads reduction methods in MITICA beam source

    Energy Technology Data Exchange (ETDEWEB)

    Sartori, E., E-mail: emanuele.sartori@igi.cnr.it; Agostinetti, P.; Dal Bello, S.; Marcuzzi, D.; Serianni, G.; Veltri, P. [Consorzio RFX, Euratom-ENEA association, C.so Stati Uniti 4, 35127 Padova (Italy); Sonato, P. [Consorzio RFX, Euratom-ENEA association, C.so Stati Uniti 4, 35127 Padova (Italy); Dipartimento di Ingegneria Elettrica, Padova University, Via Gradenigo 6/a, 35131 Padova (Italy)

    2014-02-15

    In negative ion electrostatic accelerators a considerable fraction of extracted ions is lost by collision processes causing efficiency loss and heat deposition over the components. Stripping is proportional to the local density of gas, which is steadily injected in the plasma source; its pumping from the extraction and acceleration stages is a key functionality for the prototype of the ITER Neutral Beam Injector, and it can be simulated with the 3D code AVOCADO. Different geometric solutions were tested aiming at the reduction of the gas density. The parameter space considered is limited by constraints given by optics, aiming, voltage holding, beam uniformity, and mechanical feasibility. The guidelines of the optimization process are presented together with the proposed solutions and the results of numerical simulations.

  2. Correlation of beam loss to residual activation in the AGS

    International Nuclear Information System (INIS)

    Brown, K.A.

    1991-01-01

    Studies of beam loss and activation at the AGS have provided a better understanding of measurements of beam loss and how they may be used to predict activation. Studies have been done in which first order correlations have been made between measured beam losses on the distributed ionization chamber system in the AGS and the health physics recorded residual activation. These studies have provided important insight into the ionization chamber system, its limitations, and its usefulness in the prediction of activation based on monitored beam loss. In recent years the AGS has run high intensity protons primarily for rare kaon decay experiments. In this mode of running the AGS typically accelerates beam from an injection momentum of 0.644 GeV/c up to a slow extracted beam (SEB) momentum of 24.2 GeV/c. The beam intensities are on the order of 4.5 x 10 13 protons per AGS cycle at injection to as high as 1.9 x 10 13 protons per AGS cycle at extraction. Residual activation varies around the AGS ring from the order of 5 mR/hour to levels of the order at 5 R/hour. The highest levels occur around the AGS beam catcher and the extraction equipment

  3. Tolerable Beam Loss at High-Intensity Machines

    International Nuclear Information System (INIS)

    Krivosheev, Oleg E.; Mokhov, Nikolai V.

    2000-01-01

    Tolerable beam losses are estimated for high-intensity ring accelerators with proton energy of 3 to 16 GeV. Dependence on beam energy, lattice and magnet geometry is studied via full Monte Carlo MARS14 simulations in lattice elements, shielding, tunnel and surrounding dirt with realistic geometry, materials and magnetic fields

  4. The beam loss monitoring system for HLS storage ring

    CERN Document Server

    Li Yu Xiong; Li Wei; Li Jue Xin; Liu Zu Ping; Shao Bei Bei

    2001-01-01

    A beam loss monitoring system has been established at HLS. This paper gives its principle and scientific grounds. Study on the ring's TBA structure and utilization of Monte-Carlo calculation to the shower electrons is important in its design. The system composition and performance are also introduced. The detector BLMs, data acquisition devices and host PC are linked via CAN bus. This system is helpful to analyze beam loss distribution and regulate the machine operation parameters.

  5. A Versatile Beam Loss Monitoring System for CLIC

    CERN Document Server

    Kastriotou, Maria; Farabolini, Wilfrid; Holzer, Eva Barbara; Nebot Del Busto, Eduardo; Tecker, Frank; Welsch, Carsten

    2016-01-01

    The design of a potential CLIC beam loss monitoring (BLM) system presents multiple challenges. To successfully cover the 48 km of beamline, ionisation chambers and optical fibre BLMs are under investigation. The former fulfils all CLIC requirements but would need more than 40000 monitors to protect the whole facility. For the latter, the capability of reconstructing the original loss position with a multi-bunch beam pulse and multiple loss locations still needs to be quantified. Two main sources of background for beam loss measurements are identified for CLIC. The two-beam accelerator scheme introduces so-called crosstalk, i.e. detection of losses originating in one beam line by the monitors protecting the other. Moreover, electrons emitted from the inner surface of RF cavities and boosted by the high RF gradients may produce signals in neighbouring BLMs, limiting their ability to detect real beam losses. This contribution presents the results of dedicated experiments performed in the CLIC Test Facility to qu...

  6. DATA ACQUISITION FOR SNS BEAM LOSS MONITOR SYSTEM

    International Nuclear Information System (INIS)

    YENG, Y.; GASSNER, D.; HOFF, L.; WITKOVER, R.

    2003-01-01

    The Spallation Neutron Source (SNS) beam loss monitor system uses VME based electronics to measure the radiation produced by lost beam. Beam loss signals from cylindrical argon-filled ion chambers and neutron detectors will be conditioned in analog front-end (AFE) circuitry. These signals will be digitized and further processed in a dedicated VME crate. Fast beam inhibit and low-level, long-term loss warnings will be generated to provide machine protection. The fast loss data will have a bandwidth of 35kHz. While the low level, long-term loss data will have much higher sensitivity. This is further complicated by the 3 decade range of intensity as the Ring accumulates beam. Therefore a bandwidth of 100kHz and dynamic range larger than 21 bits data acquisition system will be required for this purpose. Based on the evaluation of several commercial ADC modules in preliminary design phase, a 24 bits Sigma-Delta data acquisition VME bus card was chosen as the SNS BLM digitizer. An associated vxworks driver and EPICS device support module also have been developed at BNL. Simulating test results showed this system is fully qualified for both fast loss and low-level, long-term loss application. The first prototype including data acquisition hardware setup and EPICS software (running database and OPI clients) will be used in SNS Drift Tube Linac (DTL) system commissioning

  7. Modeling of neutral beam ion loss from CHS plasmas

    International Nuclear Information System (INIS)

    Darrow, D.S.; Isobe, Mitsutaka; Sasao, Mamiko; Kondo, T.

    2000-01-01

    Beam ion loss measurements from Compact Helical System (CHS) plasmas under a variety of conditions show a strong loss of ions in the range of pitch angles corresponding to transition orbits at the probe location. A numerical model has been developed which includes the beam ion orbits, and details of the detector, plasma, vessel, and neutral beam geometry. From this, the expected classical (i.e. collisionless single particle orbit) signal at the detector can be computed. Preliminary comparisons between the experimental data and model predictions indicate that the classical behavior of the orbits and the machine geometry are insufficient to explain the observations. (author)

  8. PSR experience with beam losses, instabilities and space charge effects

    International Nuclear Information System (INIS)

    Macek, R.J.

    1998-01-01

    Average current from the PSR has been limited to ∼70 μA at 20 Hz by beam losses of 0.4 to 0.5 μA which arise from two principal causes, production of H 0 excited states and stored-beam scattering in the stripper foil. To reduce beam losses, an upgrade from the two-step H 0 injection to direct H - injection is underway and will be completed in 1998. Peak intensity from the PSR is limited by a strong instability that available evidence indicates is the two-stream e-p instability. New evidence for the e-p hypothesis is presented. At operating intensities, the incoherent space charge tune shift depresses both horizontal and vertical tunes past the integer without additional beam loss although some intensity-dependent emittance growth is observed. copyright 1998 American Institute of Physics

  9. PSR experience with beam losses, instabilities and space charge effects

    International Nuclear Information System (INIS)

    Macek, Robert J.

    1998-01-01

    Average current from the PSR has been limited to ∼70 μA at 20 Hz by beam losses of 0.4 to 0.5 μA which arise from two principal causes, production of H 0 excited states and stored-beam scattering in the stripper foil. To reduce beam losses, an upgrade from the two-step H 0 injection to direct H - injection is underway and will be completed in 1998. Peak intensity from the PSR is limited by a strong instability that available evidence indicates is the two-stream e-p instability. New evidence for the e-p hypothesis is presented. At operating intensities, the incoherent space charge tune shift depresses both horizontal and vertical tunes past the integer without additional beam loss although some intensity-dependent emittance growth is observed

  10. Beam Loss Calibration Studies for High Energy Proton Accelerators

    CERN Document Server

    Stockner, M

    2007-01-01

    CERN's Large Hadron Collider (LHC) is a proton collider with injection energy of 450 GeV and collision energy of 7 TeV. Superconducting magnets keep the particles circulating in two counter rotating beams, which cross each other at the Interaction Points (IP). Those complex magnets have been designed to contain both beams in one yoke within a cryostat. An unprecedented amount of energy will be stored in the circulating beams and in the magnet system. The LHC outperforms other existing accelerators in its maximum beam energy by a factor of 7 and in its beam intensity by a factor of 23. Even a loss of a small fraction of the beam particles may cause the transition from the superconducting to the normal conducting state of the coil or cause physical damage to machine components. The unique combination of these extreme beam parameters and the highly advanced superconducting technology has the consequence that the LHC needs a more efficient beam cleaning and beam loss measurement system than previous accelerators....

  11. Beam loss control in the LINAC4 design

    CERN Document Server

    Stovall, J; Crandall, K

    2010-01-01

    The Linac4 DTL reference design has been modified to reduce the power consumption in tank 1 by modifying the accelerating field and phase law. In addition we have adopted an FFDD focusing lattice throughout to minimize expected losses resulting from alignment errors. We have observed, however, that this design suffers from decreasing transverse acceptance and a sensitivity to misalignments that causes any expected beam loss to occcur at the high energy end of the DTL. In this note we investigate two solutions to increase the acceptance, decrease its sensitivity to misalignments and eliminate the potential for a beam-loss “bottleneck” at 50 MeV.

  12. Application of diamond based beam loss monitors at LHC

    Energy Technology Data Exchange (ETDEWEB)

    Hempel, Maria

    2013-04-15

    The Large Hadron Collider (LHC) was conceived in the 1980s and started the operation in 2008. It needed more than 20 years to plan and construct this accelerator and its experiments. Four main experiments are located around the ring, Compact Muon Solenoid (CMS), A Toroidal LHC Apparatus(ATLAS), A Large Ion Collider Experiment (ALICE) and LHC beauty (LHCb). Two beams that traveling in opposite direction in the LHC tunnel, collide in each of the experiments to study the questions: ''What is mass?'', ''What is the universe made of?'' and ''Why is there no antimatter?''. The four experiments take data of the collision products and try to answer the fundamental questions of physics. The two larger detectors, CMS and ATLAS, are looking for the Higgs boson to study the electroweak symmetry breaking. Both detectors were built with contrasting concepts to exclude potential error sources and to rea rm the results. The smaller experiment LHCb studies the matter-antimatter asymmetry with a focus of the beauty quark. Another smaller experiment is ALICE that studies the conditions right after the Big Bang by colliding heavy ions. The navigation of the beams is done by over 10000 magnets and each beam has a stored energy of 362MJ which correspond to the kinetic energy of a train like the TGV travelling of 150 km/h. Only a small percentage of that energy can damage the material in the LHC ring or the magnets. This would mean a repair time of months or years, without taking any data. To avoid such a scenario, it is important to monitor the beam condition and measure the amount of losses of the beam. Such losses can for example happen due to dust particles in the vacuum chambers or due to deviations of the beam parameters. Several systems called beam loss monitors (BLMs) can measure beam losses. This thesis concentrates on two of them, ionization chambers and diamond detectors. Over 3600 ionization chambers are installed in

  13. Application of diamond based beam loss monitors at LHC

    International Nuclear Information System (INIS)

    Hempel, Maria

    2013-04-01

    The Large Hadron Collider (LHC) was conceived in the 1980s and started the operation in 2008. It needed more than 20 years to plan and construct this accelerator and its experiments. Four main experiments are located around the ring, Compact Muon Solenoid (CMS), A Toroidal LHC Apparatus(ATLAS), A Large Ion Collider Experiment (ALICE) and LHC beauty (LHCb). Two beams that traveling in opposite direction in the LHC tunnel, collide in each of the experiments to study the questions: ''What is mass?'', ''What is the universe made of?'' and ''Why is there no antimatter?''. The four experiments take data of the collision products and try to answer the fundamental questions of physics. The two larger detectors, CMS and ATLAS, are looking for the Higgs boson to study the electroweak symmetry breaking. Both detectors were built with contrasting concepts to exclude potential error sources and to rea rm the results. The smaller experiment LHCb studies the matter-antimatter asymmetry with a focus of the beauty quark. Another smaller experiment is ALICE that studies the conditions right after the Big Bang by colliding heavy ions. The navigation of the beams is done by over 10000 magnets and each beam has a stored energy of 362MJ which correspond to the kinetic energy of a train like the TGV travelling of 150 km/h. Only a small percentage of that energy can damage the material in the LHC ring or the magnets. This would mean a repair time of months or years, without taking any data. To avoid such a scenario, it is important to monitor the beam condition and measure the amount of losses of the beam. Such losses can for example happen due to dust particles in the vacuum chambers or due to deviations of the beam parameters. Several systems called beam loss monitors (BLMs) can measure beam losses. This thesis concentrates on two of them, ionization chambers and diamond detectors. Over 3600 ionization chambers are installed in the LHC, especially near each quadrupole and next to

  14. Protection against Accidental Beam Losses at the LHC

    CERN Document Server

    Wenninger, Jörg

    2005-01-01

    Protection of the LHC against uncontrolled beam losses is of prime importance due to the very high stored beam energy. For nominal beam intensities, each of the two 7 TeV/c proton beams has a stored energy of 360 MJ threatening to damage accelerator equipment. At injection a number of passive beam absorbers must be correctly positioned and specific procedures have been proposed to ensure safe injection of high intensity. The LHC beam dump block being the only LHC element that can safety absorb the full LHC beam, it is essential that the beams are extracted unto the dump block in case of emergency. The failure time constants extend from 100 microseconds to few seconds depending on the equipment. Failures must be detected at a sufficiently early stage and transmitted to the beam interlock system that triggers the beam dumping system. To ensure safe operation the machine protection system uses a variety of systems to detect such failures. The strategy for protection of the LHC will be illustrated, with emphasis ...

  15. The Beam Loss Detection System of the LHC Ring

    CERN Document Server

    Gschwendtner, E; Ferioli, G; Friesenbichler, W; Kain, V

    2002-01-01

    At the Large Hadron Collider (LHC) a beam loss system will be installed in the arc, dispersion suppressor and the straight regions for a continuous surveillance of particle losses. These beam particles deposit their energy partially in the super-conducting coils leading to temperature increase, possible magnet quenches and damages. The primary and secondary halo of the beam is absorbed by the collimation system. The tertiary halo will be lost at aperture limits in the ring. Its loss distribution along the magnets has been studies. At the positions, where most of the beam losses are expected, simulations of the particle fluences outside the cryostat and induced by lost protons at the aperture have been performed with the Monte Carlo Code Geant 3.2.1. This allows determining the most suitable positions of the detectors, the needed number of monitors and the impact on the dynamic range of the detectors. The design of the beam loss monitor system is presented that meet the required sensitivity, dynamic range and ...

  16. 2014 Joint International Accelerator School: Beam Loss and Accelerator Protection

    CERN Document Server

    JAS - Joint US-CERN-Japan-Russia Accelerator School

    2016-01-01

    Many particle accelerators operate with very high beam power and very high energy stored in particle beams as well as in magnet systems. In the future, the beam power in high intensity accelerators will further increase. The protection of the accelerator equipment from the consequences of uncontrolled release of the energy is essential. This was the motivation for organizing a first school on beam losses and accelerator protection (in general referred to as machine protection). During the school the methods and technologies to identify, mitigate, monitor and manage the technical risks associated with the operation of accelerators with high-power beams or subsystems with large stored energy were presented. At the completion of the school the participants should have been able to understand the physical phenomena that can damage machine subsystems or interrupt operations and to analyze an accelerator facility to produce a register of technical risks and the corresponding risk mitigation and management strategie...

  17. SPS transverse beam scraping and LHC injection losses

    CERN Document Server

    Drosdal, L; Bartmann, W; Bracco, C; Cornelis, K; Goddard, B; Meddahi, M; Veyrunes, E

    2012-01-01

    Machine protection sets strict requirements for the quality of the injected beam, in particular in the transverse plane. Losses at aperture restrictions and protection elements have to be kept at a minimum. Particles in the beam tails are lost at the tight transfer line collimators and can trigger the LHC beam abort system. These particles have to be removed by scrapers in the vertical and horizontal plane in the SPS. Scraping has become vital for high intensity LHC operation. This paper shows the dependence of injection quality on the SPS scraping and discusses an improved scraper setting up strategy for better reproducibility with the current scraper system.

  18. IFMIF-LIPAc Beam Diagnostics. Profiling and Loss Monitoring Systems

    International Nuclear Information System (INIS)

    Egberts, J.

    2012-01-01

    The IFMIF accelerator will accelerate two 125 mA continuous wave (cw) deuteron beams up to 40 MeV and blasts them onto a liquid lithium target to release neutrons. The very high beam power of 10 MW pose unprecedented challenges for the accelerator development. Therefore, it was decided to build a prototype accelerator, the Linear IFMIF Prototype Accelerator (LIPAc), which has the very same beam characteristic, but is limited to 9 MeV only. In the frame of this thesis, diagnostics devices for IFMIF and LIPAc have been developed. The diagnostics devices consist of beam loss monitors and interceptive as well as non-interceptive profile monitors. For the beam loss monitoring system, ionization chambers and diamond detectors have been tested and calibrated for neutron and γ radiation in the energy range expected at LIPAc. During these tests, for the first time, diamond detectors were successfully operated at cryogenic temperatures. For the interceptive profilers, thermal simulations were performed to ensure safe operation. For the non-interceptive profiler, Ionization Profile Monitors (IPMs) were developed. A prototype has been built and tested, and based on the findings, the final IPMs were designed and built. To overcome the space charge of accelerator beam, a software algorithm was written to reconstruct the actual beam profile. (author) [fr

  19. Ionisation Chambers for the LHC Beam Loss Detection

    CERN Document Server

    Gschwendtner, E; Dehning, B; Ferioli, G; Kain, V

    2003-01-01

    At the Large Hadron Collider (LHC) a beam loss system will be used to prevent and protect superconducting magnets against coil quenches and coil damages. Since the stored particle beam intensity is 8 orders of magnitude larger than the lowest quench level value particular attention is paid to the design of the secondary particle shower detectors. The foreseen ionisation chambers are optimised in geometry simulating the probable loss distribution along the magnets and convoluting the loss distribution with the secondary particle shower distributions. To reach the appropriate coverage of a particle loss and to determine the quench levels with a relative accuracy of 2 the number of the detectors and their lengths is weighted against the particle intensity density variation. In addition attention is paid to the electrical ionisation chamber signal to minimise the ion tail extension. This optimisation is based on time resolved test measurements in the PS booster. A proposal for a new ionisation chamber will be pre...

  20. Cherenkov Fibers for Beam Loss Monitoring at the CLIC Two Beam Module

    CERN Document Server

    van Hoorne, Jacobus Willem; Holzer, E B

    The Compact Linear Collider (CLIC) study is a feasibility study aiming at a nominal center of mass energy of 3TeV and is based on normal conducting travelling-wave accelerating structures, operating at very high field gradients of 100 MV/m. Such high fields require high peak power and hence a novel power source, the CLIC two beam system, has been developed, in which a high intensity, low energy drive beam (DB) supplies energy to a high energy, low intensity main beam (MB). At the Two Beam Modules (TBM), which compose the 2x21km long CLIC main linac, a protection against beam losses resulting from badly controlled beams is necessary and particularly challenging, since the beam power of both main beam (14 MW) and drive beam (70 MW) is impressive. To avoid operational downtimes and severe damages to machine components, a general Machine Protection System (MPS) scheme has been developed. The Beam Loss Monitoring (BLM) system is a key element of the CLIC machine protection system. Its main role will be to detect p...

  1. Identification of LHC beam loss mechanism: a deterministic treatment of loss patterns

    International Nuclear Information System (INIS)

    Marsili, A.

    2012-01-01

    The goal of this work was to identify patterns in the beam loss profiles, both in their spatial distribution and time evolution. CERN's Large Hadron Collider (LHC) is the largest device ever built, with a total circumference of 26.7 km; and it is the most powerful accelerator ever, both in beam energy and beam intensity. The main magnets are superconducting, and contain the particles into two counter circulating beams which collide in four interaction points. CERN and the LHC will be described in chapter 1. The superconducting magnets of the LHC have to be protected against particle losses. Depending on the number of lost particles, the coils of the magnets could become normal conducting and/or will be damaged. To avoid these events a beam loss monitoring (BLM) system was installed to measure the particle loss rates. If the predefined safe thresholds of loss rates are exceeded, the beams are directed out of the accelerator ring towards the beam dump. The detectors of the BLM system are mainly ionization chambers located outside of the cryostats. In total, about 3600 ionisation chambers are installed. Further challenges include the high dynamical range of losses (chamber currents ranging between 2 pA and 1 mA). The BLM system will be further described in chapter 2. The subject of this thesis is to study the loss patterns and nd the origin of the losses in a deterministic way, by comparing measured losses to well understood loss scenarios. This is done through a case study: different techniques were used on a restrained set of loss scenarios, as a proof of concept of the possibility to extract information from a loss profile. Finding the origin of the losses should allow acting in response. A justification of the doctoral work will be given at the end of chapter 2. This thesis will then focus on the theoretical understanding and the implementation of the decomposition of a measured loss profile as a linear combination of the reference scenarios; and the evaluation of

  2. Beam Loss Monitoring for Run 2 of the LHC

    CERN Document Server

    Kalliokoski, Matti; Dehning, Bernd; Domingues Sousa, Fernando; Effinger, Ewald; Emery, Jonathan; Grishin, Viatcheslav; Holzer, Eva Barbara; Jackson, Stephen; Kolad, Blazej; Nebot Del Busto, Eduardo; Picha, Ondrej; Roderick, Chris; Sapinski, Mariusz; Sobieszek, Marcin; Zamantzas, Christos

    2015-01-01

    The Beam Loss Monitoring (BLM) system of the LHC consists of over 3600 ionization chambers. The main task of the system is to prevent the superconducting magnets from quenching and protect the machine components from damage, as a result of critical beam losses. The BLM system therefore requests a beam abort when the measured dose in the chambers exceeds a threshold value. During Long Shutdown 1 (LS1) a series of modifications were made to the system. Based on the experience from Run 1 and from improved simulation models, all the threshold settings were revised, and modified where required. This was done to improve the machine safety at 7 TeV, and to reduce beam abort requests when neither a magnet quench or damage to machine components is expected. In addition to the updates of the threshold values, about 800 monitors were relocated. This improves the response to unforeseen beam losses in the millisecond time scale due to micron size dust particles present in the vacuum chamber. This contribution will discuss...

  3. Shielding NSLS-II light source: Importance of geometry for calculating radiation levels from beam losses

    Science.gov (United States)

    Kramer, S. L.; Ghosh, V. J.; Breitfeller, M.; Wahl, W.

    2016-11-01

    Third generation high brightness light sources are designed to have low emittance and high current beams, which contribute to higher beam loss rates that will be compensated by Top-Off injection. Shielding for these higher loss rates will be critical to protect the projected higher occupancy factors for the users. Top-Off injection requires a full energy injector, which will demand greater consideration of the potential abnormal beam miss-steering and localized losses that could occur. The high energy electron injection beam produces significantly higher neutron component dose to the experimental floor than a lower energy beam injection and ramped operations. Minimizing this dose will require adequate knowledge of where the miss-steered beam can occur and sufficient EM shielding close to the loss point, in order to attenuate the energy of the particles in the EM shower below the neutron production threshold (weaknesses in the design before a high radiation incident occurs. The effort required to adequately define the accelerator geometry for these codes has been greatly reduced with the implementation of the graphical interface of FLAIR to FLUKA. This made the effective shielding process for NSLS-II quite accurate and reliable. The principles used to provide supplemental shielding to the NSLS-II accelerators and the lessons learned from this process are presented.

  4. Beam loss reduction by magnetic shielding using beam pipes and bellows of soft magnetic materials

    Science.gov (United States)

    Kamiya, J.; Ogiwara, N.; Hotchi, H.; Hayashi, N.; Kinsho, M.

    2014-11-01

    One of the main sources of beam loss in high power accelerators is unwanted stray magnetic fields from magnets near the beam line, which can distort the beam orbit. The most effective way to shield such magnetic fields is to perfectly surround the beam region without any gaps with a soft magnetic high permeability material. This leads to the manufacture of vacuum chambers (beam pipes and bellows) with soft magnetic materials. A Ni-Fe alloy (permalloy) was selected for the material of the pipe parts and outer bellows parts, while a ferritic stainless steel was selected for the flanges. An austenitic stainless steel, which is non-magnetic material, was used for the inner bellows for vacuum tightness. To achieve good magnetic shielding and vacuum performances, a heat treatment under high vacuum was applied during the manufacturing process of the vacuum chambers. Using this heat treatment, the ratio of the integrated magnetic flux density along the beam orbit between the inside and outside of the beam pipe and bellows became small enough to suppress beam orbit distortion. The outgassing rate of the materials with this heat treatment was reduced by one order magnitude compared to that without heat treatment. By installing the beam pipes and bellows of soft magnetic materials as part of the Japan Proton Accelerator Research Complex 3 GeV rapid cycling synchrotron beam line, the closed orbit distortion (COD) was reduced by more than 80%. In addition, a 95.5% beam survival ratio was achieved by this COD improvement.

  5. Long radiation detector system for beam loss monitoring

    International Nuclear Information System (INIS)

    Balsamo, J.; Fewell, N.M.; Klein, J.D.; Witkover, R.L.

    1977-01-01

    The Long Radiation Monitor (LRM) system installed at the 200 MeV linac at Brookhaven National Laboratory is described. This system allows observation of both the spatial and temporal character of the losses in the linac and its transport lines. An array of large diameter gas filled coaxial cables are used as extended ion chambers to detect the losses. The output signals are available as a histogram, video waveforms, and numerical data via the computer. A fast beam interrupt is also provided. The detector characteristics and details of the processing electronics are presented. Results of studies of longitudinal, steering and focusing losses are described

  6. Long radiation detector system for beam loss monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Balsamo, J.; Fewell, N.M.; Klein, J.D.; Witkover, R.L.

    1977-01-01

    The Long Radiation Monitor (LRM) system installed at the 200 MeV linac at Brookhaven National Laboratory is described. This system allows observation of both the spatial and temporal character of the losses in the linac and its transport lines. An array of large diameter gas filled coaxial cables are used as extended ion chambers to detect the losses. The output signals are available as a histogram, video waveforms, and numerical data via the computer. A fast beam interrupt is also provided. The detector characteristics and details of the processing electronics are presented. Results of studies of longitudinal, steering and focusing losses are described.

  7. Identification of LHC beam loss mechanism : a deterministic treatment of loss patterns

    CERN Document Server

    Marsili, Aurélien

    CERN's Large Hadron Collider (LHC) is the largest machine ever built, with a total circumference of 26.7 km; and it is the most powerful accelerator ever, both in beam energy and beam intensity. The main magnets are superconducting, keeping the particles into two counter circulating beams, which collide in four interaction points. CERN and the LHC will be described in chap. 1. The superconducting magnets of the LHC have to be protected against particle losses. Depending on the number of lost particles, the coils of the magnets will become normal conducting and/or will be damaged. To avoid these events a beam loss monitoring (BLM) system was installed to measure the particle loss rates. If the predefined safe thresholds of loss rates are exceeded, the beams are directed out of the accelerator ring towards the beam dump. The detectors of the BLM system are mainly ionization chambers located outside of the cryostats. In total, about 3500 ionisation chambers are installed. Further challenges include the high dyna...

  8. LHC Beam Instrumentation: Beam Loss and Tune Measurements (3/3)

    CERN Multimedia

    CERN. Geneva

    2014-01-01

    The LHC is equipped with a full suite of sophisticated beam instrumentation which has been essential for rapid commissioning, the safe increase in total stored beam power and the understanding of machine optics and accelerator physics phenomena. These lectures will introduce these systems and comment on their contributions to the various stages of beam operation. They will include details on: the beam position system and its use for real-time global orbit feedback; the beam loss system and its role in machine protection; total and bunch by bunch intensity measurements; tune measurement and feedback; diagnostics for transverse beam size measurements, abort gap monitoring and longitudinal density measurements. Issues and problems encountered along the way will also be discussed together with the prospect for future upgrades.

  9. Local energy losses at positive and negative steps in subcritical ...

    African Journals Online (AJOL)

    Local energy losses occur when there is a transition in open channel flow. Even though local losses in subcritical open channel flow due to changes in channel width have been studied, to date no studies have been reported for losses due to changes in bed elevations. Steps are commonly used in engineering applications ...

  10. Ionization Chambers for the LHC Beam Loss Detection

    CERN Document Server

    Assmann, R W; Ferioli, G; Gschwendtner, E; Kain, V

    2003-01-01

    At the Large Hadron Collider (LHC) a beam loss system will be used to prevent and protect superconducting magnets against coil quenches and coil damages. Ionisation chambers will be mounted outside the cryostat to measure the secondary shower particles caused by lost beam particles. Since the stored particle beam intensity is eight orders of magnitude larger than the lowest quench level and the losses should be detected with a relative error of two, the design and the location of the detectors have to be optimised. For that purpose a two-fold simulation was carried out. The longitudinal loss locations of the tertiary halo is investigated by tracking the halo through several magnet elements. These loss distributions are combined with simulations of the particle fluence outside the cryostat, which is induced by lost protons at the vacuum pipe. The base-line ionisation chamber has been tested at the PS Booster in order to determine the detector response at the high end of the dynamic range.

  11. A Fast CVD Diamond Beam Loss Monitor for LHC

    CERN Document Server

    Griesmayer, E; Dobos, D; Effinger, E; Pernegger, H

    2011-01-01

    Chemical Vapour Deposition (CVD) diamond detectors were installed in the collimation area of the CERN LHC to study their feasibility as Fast Beam Loss Monitors in a high-radiation environment. The detectors were configured with a fast, radiation-hard pre-amplifier with a bandwidth of 2 GHz. The readout was via an oscilloscope with a bandwidth of 1 GHz and a sampling rate of 5 GSPS. Despite the 250 m cable run from the detectors to the oscilloscope, single MIPs were resolved with a 2 ns rise time, a pulse width of 10 ns and a time resolution of less than 1 ns. Two modes of operation were applied. For the analysis of unexpected beam aborts, the loss profile was recorded in a 1 ms buffer and, for nominal operation, the histogram of the time structure of the losses was recorded in synchronism with the LHC period of 89.2 μs. Measurements during the LHC start-up (February to December 2010) are presented. The Diamond Monitors gave an unprecedented insight into the time structure of the beam losses resolving the 400...

  12. RFQ Designs and Beam-Loss Distributions for IFMIF

    Energy Technology Data Exchange (ETDEWEB)

    Jameson, Robert A [ORNL

    2007-01-01

    The IFMIF 125 mA cw 40 MeV accelerators will set an intensity record. Minimization of particle loss along the accelerator is a top-level requirement and requires sophisticated design intimately relating the accelerated beam and the accelerator structure. Such design technique, based on the space-charge physics of linear accelerators (linacs), is used in this report in the development of conceptual designs for the Radio-Frequency-Quadrupole (RFQ) section of the IFMIF accelerators. Design comparisons are given for the IFMIF CDR Equipartitioned RFQ, a CDR Alternative RFQ, and new IFMIF Post-CDR Equipartitioned RFQ designs. Design strategies are illustrated for combining several desirable characteristics, prioritized as minimum beam loss at energies above ~ 1 MeV, low rf power, low peak field, short length, high percentage of accelerated particles. The CDR design has ~0.073% losses above 1 MeV, requires ~1.1 MW rf structure power, has KP factor 1.7,is 12.3 m long, and accelerates ~89.6% of the input beam. A new Post-CDR design has ~0.077% losses above 1 MeV, requires ~1.1 MW rf structure power, has KP factor 1.7 and ~8 m length, and accelerates ~97% of the input beam. A complete background for the designs is given, and comparisons are made. Beam-loss distributions are used as input for nuclear physics simulations of radioactivity effects in the IFMIF accelerator hall, to give information for shielding, radiation safety and maintenance design. Beam-loss distributions resulting from a ~1M particle input distribution representative of the IFMIF ECR ion source are presented. The simulations reported were performed with a consistent family of codes. Relevant comparison with other codes has not been possible as their source code is not available. Certain differences have been noted but are not consistent over a broad range of designs and parameter range. The exact transmission found by any of these codes should be treated as indicative, as each has various sensitivities in

  13. Performance and perspectives of the diamond based Beam Condition Monitor for beam loss monitoring at CMS

    CERN Document Server

    AUTHOR|(CDS)2080862

    2015-01-01

    At CMS, a beam loss monitoring system is operated to protect the silicon detectors from high particle rates, arising from intense beam loss events. As detectors, poly-crystalline CVD diamond sensors are placed around the beam pipe at several locations inside CMS. In case of extremely high detector currents, the LHC beams are automatically extracted from the LHC rings.Diamond is the detector material of choice due to its radiation hardness. Predictions of the detector lifetime were made based on FLUKA monte-carlo simulations and irradiation test results from the RD42 collaboration, which attested no significant radiation damage over several years.During the LHC operational Run1 (2010 â?? 2013), the detector efficiencies were monitored. A signal decrease of about 50 times stronger than expectations was observed in the in-situ radiation environment. Electric field deformations due to charge carriers, trapped in radiation induced lattice defects, are responsible for this signal decrease. This so-called polarizat...

  14. Beam losses and beam halos in accelerators for new energy sources

    International Nuclear Information System (INIS)

    Jameson, R.A.

    1995-01-01

    Large particle accelerators are proposed as drivers for new ways to produce electricity from nuclear fusion and fission reactions. The accelerators must be designed to deliver large particle beam currents to a target facility with very little beam spill along the accelerator itself, in order that accelerator maintenance can be accomplished without remote manipulators. Typically, particle loss is preceded by the formation of a tenuous halo of particles around the central beam core, caused by beam dynamics effects, often coupled with the slight imperfections inevitable in a practical design. If the halo becomes large enough, particles may be scraped off along the accelerator. The tolerance for beam spill in different applications is discussed, halo mechanisms and recent work to explore and understand their dynamics are reviewed, and possible directions for future investigation are outlined. 17 refs., 10 figs

  15. Beam Losses and Lifetime of the LHC Beam in the SPS

    CERN Document Server

    Bohl, T; Shaposhnikova, Elena; Tückmantel, Joachim

    2006-01-01

    Studies of the LHC beam loss in the SPS started in 2003 [1], [2] and continued in 2004. The flat bottom losses strongly depend on the batch intensity and the RF voltage. For beam with the 75 ns spacing at the same bunch intensity they are smaller than for the 25 ns spaced bunches. Large voltage on the flat bottom together with some optimum voltage at injection helps to reduce losses. Analysis of data from 2003 has shown that observations are compatible with a diffusion like process on the flat bottom. Therefore significant time during 2004 was devoted to studies of possible RF noise sources. However the main improvement in beam lifetime on the flat bottom was observed after a change in the working point in the transverse plane (MD on 1.09.2004). In this Note we present measurements of beam loss and lifetime done during several dedicated SPS MDs for different conditions in the ring. Analysis of beam coasts will be presented separately.

  16. Beam energy loss to parasitic modes in SPEAR II

    International Nuclear Information System (INIS)

    Allen, M.A.; Paterson, J.M.; Rees, J.R.; Wilson, P.B.

    1975-01-01

    The energy loss due to the excitation of parasitic modes in the SPEAR II rf cavities and vacuum chamber components was measured by observing the shift in synchronous phase angle as a function of circulating beam current and accelerating cavity voltage. The resulting parasitic mode loss resistance is 5 M OMEGA at a bunch length of 6.5 cm. The loss resistance varies with bunch length sigma/sub z/ approximately as exp(-0.3 sigma/sub z/). If the measured result is compared with reasonable theoretical predictions, it may be inferred that the major portion of the parasitic loss takes place in ring vacuum components rather than in the rf cavities. (auth)

  17. Chlorine loss and mass loss from polyvinylchloride and polyvinylidenchloride under the electron beam

    International Nuclear Information System (INIS)

    Lindberg, K.A.H.; Bertilsson, H.E.

    1985-01-01

    The loss of chlorine during the irradiation of PVC and PVDC in the electron microscope has been measured by the decay of the X-ray chlorine Kα signal. A number of factors affecting the measured beam damage curves have been considered and the experimental errors reduced to +- 10%. The results show that the chlorine decay curves can be best described by the sum of two exponentials, corresponding to the two different chlorine decay processes, these being: the dehydrochlorination of the polymer molecules and the dehydrochlorination of the polyene structure formed by the beam damage. The higher initial chlorine content of PVDC compared to PVC will result in a larger amount of chlorine atoms reacting with the polyene structure, which is more stable in the electron beam than the undamaged polymer. The chlorine loss, measured by X-ray analysis, has been compared to the mass loss, measured by energy loss analysis, and also with the volume changes of isolated spherical PVC particles. It has been concluded that the mass loss is almost entirely due to chlorine loss and that the residual structure has a density similar to the undamaged PVC. (author)

  18. Human local and total heat losses in different temperature.

    Science.gov (United States)

    Wang, Lijuan; Yin, Hui; Di, Yuhui; Liu, Yanfeng; Liu, Jiaping

    2016-04-01

    This study investigates the effects of operative temperature on the local and total heat losses, and the relationship between the heat loss and thermal sensation. 10 local parts of head, neck, chest, abdomen, upper arm, forearm, hand, thigh, leg and foot are selected. In all these parts, convection, radiation, evaporation, respiration, conduction and diffusion heat losses are analyzed when operative temperature is 23, 28, 33 and 37 °C. The local heat losses show that the radiation and convection heat losses are mainly affected by the area of local body, and the heat loss of the thigh is the most in the ten parts. The evaporation heat loss is mainly affected by the distribution of sweat gland, and the heat loss of the chest is the most. The total heat loss of the local body shows that in low temperature, the thigh, leg and chest have much heat loss, while in high temperature, the chest, abdomen, thigh and head have great heat loss, which are useful for clothing design. The heat losses of the whole body show that as the operative temperature increases, the radiation and convection heat losses decrease, the heat losses of conduction, respiration, and diffusion are almost constant, and the evaporation heat loss increases. By comparison, the heat loss ratios of the radiation, convection and sweat evaporation, are in agreement with the previous researches. At last, the formula about the heat loss ratio of convection and radiation is derived. It's useful for thermal comfort evaluation and HVAC (heating, ventilation and air conditioning) design. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. The LCLS Undulator Beam Loss Monitor Readout System

    Energy Technology Data Exchange (ETDEWEB)

    Dusatko, John; Browne, M.; Fisher, A.S.; Kotturi, D.; Norum, S.; Olsen, J.; /SLAC

    2012-07-23

    The LCLS Undulator Beam Loss Monitor System is required to detect any loss radiation seen by the FEL undulators. The undulator segments consist of permanent magnets which are very sensitive to radiation damage. The operational goal is to keep demagnetization below 0.01% over the life of the LCLS. The BLM system is designed to help achieve this goal by detecting any loss radiation and indicating a fault condition if the radiation level exceeds a certain threshold. Upon reception of this fault signal, the LCLS Machine Protection System takes appropriate action by either halting or rate limiting the beam. The BLM detector consists of a PMT coupled to a Cherenkov radiator located near the upstream end of each undulator segment. There are 33 BLMs in the system, one per segment. The detectors are read out by a dedicated system that is integrated directly into the LCLS MPS. The BLM readout system provides monitoring of radiation levels, computation of integrated doses, detection of radiation excursions beyond set thresholds, fault reporting and control of BLM system functions. This paper describes the design, construction and operational performance of the BLM readout system.

  20. 2014 CERN Accelerator Schools: Beam Loss and Accelerator Protection

    CERN Multimedia

    2014-01-01

    The US-CERN-JAPAN-RUSSIA Joint International Accelerator School is organising a course on Beam Loss and Accelerator Protection to be held in Newport Beach, California, USA from 5-14 November, 2014.    This school is intended for physicists and engineers who are or may be engaged in the design, construction, and/or operation of accelerators with high power photon or particle beams and/or accelerator sub-systems with large stored energy. Application deadlines are 15 August and 4 September. Further information on this Joint School can be found at: http://cas.web.cern.ch/cas/JAS/Newport%20Beach%202014/NPBadvert.html http://indico.cern.ch/event/287647/ http://uspas.fnal.gov/programs/JAS/JAS14.shtml

  1. Prompt loss of beam ions in KSTAR plasmas

    Directory of Open Access Journals (Sweden)

    Jun Young Kim

    2016-10-01

    Full Text Available For a toroidal plasma facility to realize fusion energy, researching the transport of fast ions is important not only due to its close relation to the heating and current drive efficiencies but also to determine the heat load on the plasma-facing components. We present a theoretical analysis and orbit simulation for the origin of lost fast-ions during neutral beam injection (NBI heating in Korea Superconducting Tokamak Advanced Research (KSTAR device. We adopted a two-dimensional phase diagram of the toroidal momentum and magnetic moment and describe detectable momentums at the fast-ion loss detector (FILD position as a quadratic line. This simple method was used to model birth ions deposited by NBI and drawn as points in the momentum phase space. A Lorentz orbit code was used to calculate the fast-ion orbits and present the prompt loss characteristics of the KSTAR NBI. The scrape-off layer deposition of fast ions produces a significant prompt loss, and the model and experimental results closely agreed on the pitch-angle range of the NBI prompt loss. Our approach can provide wall load information from the fast ion loss.

  2. Local beam angle optimization with linear programming and gradient search

    International Nuclear Information System (INIS)

    Craft, David

    2007-01-01

    The optimization of beam angles in IMRT planning is still an open problem, with literature focusing on heuristic strategies and exhaustive searches on discrete angle grids. We show how a beam angle set can be locally refined in a continuous manner using gradient-based optimization in the beam angle space. The gradient is derived using linear programming duality theory. Applying this local search to 100 random initial angle sets of a phantom pancreatic case demonstrates the method, and highlights the many-local-minima aspect of the BAO problem. Due to this function structure, we recommend a search strategy of a thorough global search followed by local refinement at promising beam angle sets. Extensions to nonlinear IMRT formulations are discussed. (note)

  3. Generation and propagation characteristics of a localized hollow beam

    Science.gov (United States)

    Xia, Meng; Wang, Zhizhang; Yin, Yaling; Zhou, Qi; Xia, Yong; Yin, Jianping

    2018-05-01

    A succinct experimental scheme is demonstrated to generate a localized hollow beam by using a π-phase binary bitmap and a convergent thin lens. The experimental results show that the aspect ratio of the dark-spot size of the hollow beam can be effectively controlled by the focal length of the lens. The measured beam profiles in free space also agree with the theoretical modeling. The studies hold great promise that such a hollow beam can be used to cool trapped atoms (or molecules) by Sisyphus cooling and to achieve an optically-trapped Bose–Einstein condensate by optical-potential evaporative cooling.

  4. Secondary Electron Emission Beam Loss Monitor for LHC

    CERN Document Server

    Dehning, B; Holzer, E B; Kramer, Daniel

    2008-01-01

    Beam Loss Monitoring (BLM) system is a vital part of the active protection of the LHC accelerators' elements. It should provide the number of particles lost from the primary hadron beam by measuring the radiation field induced by their interaction with matter surrounding the beam pipe. The LHC BLM system will use ionization chambers as standard detectors but in the areas where very high dose rates are expected, the Secondary Emission Monitor (SEM) chambers will be employed because of their high linearity, low sensitivity and fast response. The SEM needs a high vacuum for proper operation and has to be functional for up to 20 years, therefore all the components were designed according to the UHV requirements and a getter pump was included. The SEM electrodes are made of Ti because of its Secondary Emission Yield (SEY) stability. The sensitivity of the SEM was modeled in Geant4 via the Photo-Absorption Ionization module together with custom parameterization of the very low energy secondary electron production. ...

  5. On the validity of localized approximations for Bessel beams: All N-Bessel beams are identically equal to zero

    International Nuclear Information System (INIS)

    Gouesbet, Gérard

    2016-01-01

    Localized approximation procedures are efficient ways to evaluate beam shape coefficients of a laser beam. They are particularly useful when other methods are ineffective or inefficient. Several papers in the literature have reported the use of such procedures to evaluate the beam shape coefficients of Bessel beams. Relying on the concept of N-beams, it is demonstrated that care must be taken when constructing a localized approximation for a Bessel beam, namely a localized Bessel beam is satisfactorily close enough to the intended beam only when the axicon angle is small enough. - Highlights: • Localized approximation has been used to evaluate BSCs of Bessel beams. • N-beam procedure fails to provide a localized approximation for Bessel beams. • Localized approximation should be used only for small axicon angles.

  6. A unified approach to global and local beam position feedback

    International Nuclear Information System (INIS)

    Chung, Y.

    1994-01-01

    The Advanced Photon Source (APS) will implement both global and local beam position feedback systems to stabilize the particle and X-ray beams for the storage ring. The global feedback system uses 40 BPMs and 40 correctors per plane. Singular value decomposition (SVD) of the response matrix is used for closed orbit correction. The local feedback system uses two X-ray BPMS, two rf BPMS, and the four-magnet local bump to control the angle and displacement of the X-ray beam from a bending magnet or an insertion device. Both the global and local feedback systems are based on digital signal processing (DSP) running at 4-kHz sampling rate with a proportional, integral, and derivative (PID) control algorithm. In this paper, we will discuss resolution of the conflict among multiple local feedback systems due to local bump closure error and decoupling of the global and local feedback systems to maximize correction efficiency. In this scheme, the global feedback system absorbs the local bump closure error and the local feedback systems compensate for the effect of global feedback on the local beamlines. The required data sharing between the global and local feedback systems is done through the fiber-optically networked reflective memory

  7. Energy loss of heavy ion beams in plasma

    Energy Technology Data Exchange (ETDEWEB)

    Okada, T; Hotta, T [Tokyo Univ. of Agriculture and Technology, Koganei (Japan). Faculty of Technology

    1997-12-31

    The energy loss of heavy-ion beams (HIB) is studied by means of Vlasov theory and Particle-in-Cell (PIC) simulations in a plasma. The interaction of HIB with a plasma is of central importance for inertial confinement fusion (ICF). A number of studies on the HIB interaction with target plasma have been published. It is important for heavy-ion stopping that the effects of the non-linear interaction of HIB within the Vlasov theory are included. Reported are results of a numerical study of nonlinear effects to the stopping power for HIB in plasma. It is shown that the PIC simulations of collective effects of the stopping power are in a good agreement with the Vlasov theory. (author). 2 tabs., 1 fig., 5 refs.

  8. Loss of Energy Concentration in Nonlinear Evolution Beam Equations

    Science.gov (United States)

    Garrione, Maurizio; Gazzola, Filippo

    2017-12-01

    Motivated by the oscillations that were seen at the Tacoma Narrows Bridge, we introduce the notion of solutions with a prevailing mode for the nonlinear evolution beam equation u_{tt} + u_{xxxx} + f(u)= g(x, t) in bounded space-time intervals. We give a new definition of instability for these particular solutions, based on the loss of energy concentration on their prevailing mode. We distinguish between two different forms of energy transfer, one physiological (unavoidable and depending on the nonlinearity) and one due to the insurgence of instability. We then prove a theoretical result allowing to reduce the study of this kind of infinite-dimensional stability to that of a finite-dimensional approximation. With this background, we study the occurrence of instability for three different kinds of nonlinearities f and for some forcing terms g, highlighting some of their structural properties and performing some numerical simulations.

  9. RF Trip and Beam Loss Diagnostics in LEP using GPS timing

    CERN Document Server

    Arnaudon, L; Beetham, G; Ciapala, Edmond; Juillard, J C; Olsen, R; CERN. Geneva. SPS and LEP Division

    2000-01-01

    A fast diagnostics system has been installed in LEP to allow precise time-stamping of RF unit trips. The system also monitors the fast decay of current when a beam loss occurs. From the information gathered it is now possible to determine which RF units have provoked a beam loss at high energy and which have tripped as a result. The system uses GPS equipment installed at all of the even points of LEP together with fast local DSP acquisition and event recording units in each RF sector. An overall control application driven by the LEPExec arms the system at the start of each fill, calculates and displays RF and trip beam loss events in sequence, then stores the results in a database. The system installation was completed in time for the LEP 2000 startup and initial problems were quickly resolved. Throughout the year it has proved invaluable for high energy running. The experience gained will also be very useful for similar diagnostics applications in LHC.

  10. Beam loss due to the aperture limitation resulting from intrabeam scattering

    International Nuclear Information System (INIS)

    Lee, S.Y.

    1984-01-01

    Diffusion equation is used to evaluate the beam loss in the presence of aperture limitation resulting from the intrabeam scattering. We discuss the effect of different boundary conditions. Satisfactory beam intensity can be maintained within the proposed RHIC operation time

  11. Local beam position feedback experiments on the ESRF storage ring

    International Nuclear Information System (INIS)

    Chung, Y.; Kahana, E.; Kirchman, J.

    1995-01-01

    This paper describes the results of local beam position feedback experiments conducted on the ESRF storage ring using digital signal processing (DSP) under the trilateral agreement of collaboration among ESRF, APS, and SPring-8. Two rf beam position monitors (BPMS) in the, upstream and downstream of the insertion device (ID) and two x-ray BPMs in the sixth cell were used to monitor the electron beam and the x-ray beam emitted from the ID, respectively. The local bump coefficients were obtained using the technique of singular value decomposition (SVD) on the global response matrix for the bump magnets and all the available BPMs outside the local bump. The local response matrix was then obtained between the two three-magnet bumps and the position monitors. The data sampling frequency was 4 kHz and a proportional, integral, and derivative (PID) controller was used. The result indicates the closed-loop feedback bandwidth close to 100 Hz and clear attenuation (∼ -40 dB) of the 7-Hz beam motion due to girder vibration resonance. Comparison of the results using the rf BPMs and x-ray BPMs will be also discussed

  12. Cryogenic Beam Loss Monitors for the Superconducting Magnets of the LHC

    CERN Document Server

    Bartosik, MR; Sapinski, M; Kurfuerst, C; Griesmayer, E; Eremin, V; Verbitskaya, E

    2014-01-01

    The Beam Loss Monitor detectors close to the interaction points of the Large Hadron Collider are currently located outside the cryostat, far from the superconducting coils of the magnets. In addition to their sensitivity to lost beam particles, they also detect particles coming from the experimental collisions, which do not contribute significantly to the heat deposition in the superconducting coils. In the future, with beams of higher energy and brightness resulting in higher luminosity, distinguishing between these interaction products and dangerous quench-provoking beam losses from the primary proton beams will be challenging. The system can be optimised by locating beam loss monitors as close as possible to the superconducting coils, inside the cold mass in a superfluid helium environment, at 1.9 K. The dose then measured by such Cryogenic Beam Loss Monitors would more precisely correspond to the real dose deposited in the coil. The candidates under investigation for such detectors are based on p+-n-n+ si...

  13. Shielding NSLS-II light source: Importance of geometry for calculating radiation levels from beam losses [Shielding Synchrotron Light Sources: Importance of geometry for calculating radiation levels from beam losses

    International Nuclear Information System (INIS)

    Kramer, S. L.; Ghosh, V. J.; Breitfeller, M.; Wahl, W.

    2016-01-01

    Third generation high brightness light sources are designed to have low emittance and high current beams, which contribute to higher beam loss rates that will be compensated by Top-Off injection. Shielding for these higher loss rates will be critical to protect the projected higher occupancy factors for the users. Top-Off injection requires a full energy injector, which will demand greater consideration of the potential abnormal beam miss-steering and localized losses that could occur. The high energy electron injection beam produces significantly higher neutron component dose to the experimental floor than a lower energy beam injection and ramped operations. Minimizing this dose will require adequate knowledge of where the miss-steered beam can occur and sufficient EM shielding close to the loss point, in order to attenuate the energy of the particles in the EM shower below the neutron production threshold (<10 MeV), which will spread the incident energy on the bulk shield walls and thereby the dose penetrating the shield walls. Designing supplemental shielding near the loss point using the analytic shielding model is shown to be inadequate because of its lack of geometry specification for the EM shower process. To predict the dose rates outside the tunnel requires detailed description of the geometry and materials that the beam losses will encounter inside the tunnel. Modern radiation shielding Monte-Carlo codes, like FLUKA, can handle this geometric description of the radiation transport process in sufficient detail, allowing accurate predictions of the dose rates expected and the ability to show weaknesses in the design before a high radiation incident occurs. The effort required to adequately define the accelerator geometry for these codes has been greatly reduced with the implementation of the graphical interface of FLAIR to FLUKA. This made the effective shielding process for NSLS-II quite accurate and reliable. Lastly, the principles used to provide

  14. Commissioning and operational scenarios of the LHC beam loss monitor system

    International Nuclear Information System (INIS)

    Holzer, E.B.

    2007-01-01

    One of the most critical elements for the protection of CERN's Large Hadron Collider (LHC) is its beam loss monitoring (BLM) system. It must prevent quenches in the super conducting magnets and damage of machine components due to beam losses. The contribution will discuss the commissioning procedures of the BLM system and envisaged operational scenarios. About 4000 monitors will be installed around the ring. When the loss rate exceeds a predefined threshold value, a beam abort is requested. Magnet quench and damage levels vary as a function of beam energy and loss duration. Consequently, the beam abort threshold values vary accordingly. By measuring the loss pattern, the BLM system helps to identify the loss mechanism. Furthermore, it will be an important tool for commissioning, machine setup and studies. Special monitors will be used for the setup and control of the collimators. (author)

  15. Development, Production and Testing of 4500 Beam Loss Monitors

    CERN Document Server

    Holzer, E B; Dehning, B; Ferioli, G; Grishin, V; Jimenez, T M; Koshelev, A; Kramer, Daniel; Larionov, A; Taborelli, M; Seleznev, V; Sleptsov, M; Sytin, A; Wevers, I

    2008-01-01

    Beam-loss monitoring (BLM) [1] is a key element in the LHC machine protection. 4250 nitrogen filled ionization chambers (IC) and 350 secondary emission monitors (SEM) have been manufactured and tested at the Institute for High Energy Physics (IHEP) in Protvino, Russia, following their development at CERN. Signal speed and robustness against aging were the main design criteria. Each monitor is permanently sealed inside a stainless-steel cylinder. The quality of the welding was a critical aspect during production. The SEMs are requested to hold a vacuum of $10^{-7}$ bar. Impurity levels from thermal and radiationinduced desorption should remain in the range of parts per million in the ICs. To avoid radiation aging (up to $2·10^{8}$ Gy in 20 years) production of the chambers followed strict UHV requirements. IHEP designed and built the UHV production stand. Due to the required dynamic range of $10^{8}$, the leakage current of the monitors has to stay below 2 pA. Several tests during and after production were ...

  16. Studies of Limits on Uncontrolled Heavy Ion Beam Losses for Allowing Hands-On Maintenance

    Energy Technology Data Exchange (ETDEWEB)

    Reginald M. Ronningen; Igor Remec

    2010-09-11

    Dose rates from accelerator components activated by 1 W/m beam losses are obtained semiempirically for a 1 GeV proton beam and by use of Monte Carlo transport codes for the proton beam and for 777 MeV/u 3He, 500 MeV/u 48Ca, 86Kr, 136Xe, and 400 MeV/u 238U ions. The dose rate obtained by the semi-empirical method, 0.99 mSv/h (99 mrem/h) at 30 cm, 4 h after 100 d irradiation by a 1-GeV proton beam, is consistent with studies at several accelerator facilities and with adopted hands-on maintenance dose rate limits. Monte Carlo simulations verify this result for protons and extend studies to heavy ion beam losses in drift-tube linac and superconducting linac accelerating structures. The studies indicate that the 1 W/m limit imposed on uncontrolled beam losses for high-energy proton beams might be relaxed for heavy ion beams. These studies further suggest that using the ratio of neutrons produced by a heavy ion beam to neutrons produced by a proton beam along with the dose rate from the proton beam (for thin-target scenarios) should allow an estimate of the dose rates expected from heavy ion beam losses.

  17. Size modulated transition in the fluid–structure interaction losses in nano mechanical beam resonators

    Energy Technology Data Exchange (ETDEWEB)

    Vishwakarma, S. D.; Pratap, R., E-mail: pratap@mecheng.iisc.ernet.in [Center for Nano Science and Engineering, Indian Institute of Science, Bengaluru 560012 (India); Pandey, A. K., E-mail: ashok@iith.ac.in [Department of Mechanical and Aerospace Engineering, Indian Institute of Technology, Hyderabad, Kandi, Sangareddy - 502285 (India); Parpia, J. M.; Craighead, H. G. [Center for Materials Research, Cornell University, Ithaca, New York 14853 (United States); Verbridge, S. S. [Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, Virginia 24061 (United States)

    2016-05-21

    An understanding of the dominant dissipative mechanisms is crucial for the design of a high-Q doubly clamped nanobeam resonator to be operated in air. We focus on quantifying analytically the viscous losses—the squeeze film damping and drag force damping—that limit the net quality factor of a beam resonator, vibrating in its flexural fundamental mode with the surrounding fluid as air at atmospheric pressure. Specifically, drag force damping dominates at smaller beam widths and squeeze film losses dominate at larger beam widths, with no significant contribution from structural losses and acoustic radiation losses. The combined viscous losses agree well with the experimentally measured Q of the resonator over a large range of beam widths, within the limits of thin beam theory. We propose an empirical relation between the maximum quality factor and the ratio of maximum beam width to the squeeze film air gap thickness.

  18. Application of local vacuum slide sealing electron beam welding procedure

    International Nuclear Information System (INIS)

    Sato, Shozo; Takano, Genta; Minami, Masaharu; Enami, Koji; Uchikawa, Takashi; Kuri, Shuhei

    1982-01-01

    Electron beam welding process is efficient and is superior in workmanship and its application to the welding of large plate structures is eagerly awaited. However, since electron beam welding is generally performed with the object of welding entirely put in a vacuum chamber, high welding cost becomes a problem. In response to this demand, two kinds of local vacuum slide sealing type electron beam welding machines have been developed. These welding machines are designed to perform welding with only the neighborhood of the weld line put in vacuum, one of which is for longitudinal joints and the other for circumferential joints. The welding machine for circumferential joints has been put to practical use for the welding of nucear fusion reactor vacuum vessels (outside diameter 3.5 m, inside diameter 1.7 m), showing that it is applicable to the welding of large structures. (author)

  19. Localization and loss of coherence in molecular double slit experiments

    Energy Technology Data Exchange (ETDEWEB)

    Langer, Burkhard [Institut fuer Chemie und Biochemie - Physikalische und Theoretische Chemie, Freie Universitaet Berlin, Takustr. 3, D-14195 Berlin (Germany); Becker, Uwe, E-mail: langer@gpta.d, E-mail: becker_u@fhi-berlin.mpg.d [Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin (Germany)

    2009-11-01

    In their famous paper Einstein, Podolsky and Rosen questioned 1935 the completeness of quantum mechanics concerning a local realistic description of our reality. They argued on the basis of superpositions of position and momentum states against the inherent non-locality and loss of information on prior conditions by quantum mechanics. This pioneering proposal was, however, too vague to be implemented in any experimental proof. Consequently, angular momentum related variables such as the polarization of light became the working horse of all experiments proving the EPR predictions. However, the spin and its related polarization properties are abstract quantities compared to position and momentum. Here we present the first evidence that non-locality and loss of prior quantum state information occurs also for position in ordinary space. This shows that the tunnelling effect and entanglement are inherently correlated.

  20. Localization and loss of coherence in molecular double slit experiments

    International Nuclear Information System (INIS)

    Langer, Burkhard; Becker, Uwe

    2009-01-01

    In their famous paper Einstein, Podolsky and Rosen questioned 1935 the completeness of quantum mechanics concerning a local realistic description of our reality. They argued on the basis of superpositions of position and momentum states against the inherent non-locality and loss of information on prior conditions by quantum mechanics. This pioneering proposal was, however, too vague to be implemented in any experimental proof. Consequently, angular momentum related variables such as the polarization of light became the working horse of all experiments proving the EPR predictions. However, the spin and its related polarization properties are abstract quantities compared to position and momentum. Here we present the first evidence that non-locality and loss of prior quantum state information occurs also for position in ordinary space. This shows that the tunnelling effect and entanglement are inherently correlated.

  1. Localization and loss of coherence in molecular double slit experiments

    Science.gov (United States)

    Langer, Burkhard; Becker, Uwe

    2009-11-01

    In their famous paper Einstein, Podolsky and Rosen questioned 1935 the completeness of quantum mechanics concerning a local realistic description of our reality. They argued on the basis of superpositions of position and momentum states against the inherent non-locality and loss of information on prior conditions by quantum mechanics. This pioneering proposal was, however, too vague to be implemented in any experimental proof. Consequently, angular momentum related variables such as the polarization of light became the working horse of all experiments proving the EPR predictions. However, the spin and its related polarization properties are abstract quantities compared to position and momentum. Here we present the first evidence that non-locality and loss of prior quantum state information occurs also for position in ordinary space. This shows that the tunnelling effect and entanglement are inherently correlated

  2. Beam Loss Simulation Studies for ALS Top-Off Operation

    CERN Document Server

    Nishimura, Hiroshi; Robin, David; Steier, Christoph

    2005-01-01

    The ALS is planning to operate with top-off injection at higher beam currents and smaller vertical beam size. As part of a radiation safety study for top-off, we carried out two kinds of tracking studies: (1) to confirm that the injected beam cannot go into users' photon beam lines, and (2) to control the location of beam dump when the storage ring RF is tripped. (1) is done by tracking electrons from a photon beam line to the injection sector inversely by including the magnetic field profiles, varying the field strength with geometric aperture limits to conclude that it is impossible. (2) is done by tracking an electron with radiation in the 6-dim space for different combinations of vertical scrapers for the realistic lattice with errors.

  3. A detector for localizing diverging beams of ionizing radiations

    International Nuclear Information System (INIS)

    Allemand, Robert.

    1974-01-01

    Description is given of a detector for localizing diverging radiation beams, adapted to provide the angular distribution of nuclear events. That detector comprises a casing filled with a fluid adapted to produce electric charges under radiations and provided with a front-side and a rear-side, means for generating an electric field at right angles to portions of parallel surfaces of revolution having in common an axis of revolution contained in the place of symmetry, and a plane unit for localizing electric charges mounted at the rear of said means, the initial portion of the beam being on the axis of revolution. This can be applied to X-ray diffraction and to neutron diffraction [fr

  4. Particle Rate and Host Accelerator Beam Loss on the MICE Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Dobbs, Adam James [Imperial College, London (United Kingdom)

    2011-10-01

    A study is presented of particle rates in the MICE Muon Beamline and their relationship to beam loss produced in ISIS. A brief overview of neutrino physics is presented, together with a discussion on the Neutrino Factory as a motivation for MICE. An overview of MICE itself is then presented, highlighting the need for a systematic understanding of the relationship between the MICE target parameters, ISIS beam loss, and MICE particle rate. The variation of beam loss with target depth is examined and observed to be non-linear. The variation of beam loss with respect to the target dip time in the ISIS cycle is examined and observed to be approximately linear for dip times between 11.1 ms and 12.6 ms after ISIS injection, before tailing at earlier dip times. The variation of beam loss with particle rate is also observed to follow an approximately linear relationship from 0.05 V.ms to 4.7 V.ms beam loss, with a further strong indication that this continues up to 7.1 V.ms. Particle identification using time-of-flight data is used to give an insight into the relative abundances of each particle species present in the MICE beam. Estimates of muon rate are then produced as a function of beam loss. At a level of 2 V.ms beam loss ~10.9 muons per spill for a 3.2 ms spill with negative π → μ optics, and ~31.1 muons per 1 ms spill with positive π → μ optics are observed. Simulations using the ORBIT particle tracking code of the beam loss distributions around the ISIS ring, caused by the MICE target, are also presented and the implications for MICE running discussed.

  5. TCDQ-TCT retraction and losses during asynchronous beam dump

    CERN Document Server

    Bracco, Chiara; Quaranta, Elena; CERN. Geneva. ATS Department

    2016-01-01

    The protection provided by the TCDQs in case of asynchronous beam dump depends strongly on their correct setup. They have to respect the strict hierarchy of the full collimation system and shield the tertiary collimators in the experimental regions. This MD aimed at performing asynchronous beam dump tests with different configurations, in order to assess the minimum allowed retraction between TCTs and TCDQs and, as a consequence, on the The protection provided by the TCDQs in case of asynchronous beam dump depends strongly on their correct setup. They have to respect the strict hierarchy of the full collimation system and shield the tertiary collimators in the experimental regions. This MD aimed at performing asynchronous beam dump tests with different configurations, in order to assess the minimum allowed retraction between TCTs and TCDQs and, as a consequence, on the β* reach.

  6. Angular scattering in electron capture and loss D- beam formation processes

    International Nuclear Information System (INIS)

    Coggiola, M.J.; Hodges, R.V.; Huestis, D.L.; Peterson, J.R.

    1980-01-01

    The development of high energy (> 150 keV) neutral beams for heating and fueling magnetic fusion devices depends on the ability to produce well-collimated negative ion beams. The double capture charge-exchange technique is a known, scalable method. In order to maximize the overall efficiency of the process and to achieve the desired beam characteristics, it is necessary to examine the optical qualities of the beams as well as the total efficiency of beam production. A combined modeling and experimental study of the angular scattering effects in negative ion formation and loss processes has therefore been undertaken

  7. Consideration of neutral beam prompt loss in the design of a tokamak helicon antenna

    International Nuclear Information System (INIS)

    Pace, D.C.; Van Zeeland, M.A.; Fishler, B.; Murphy, C.

    2016-01-01

    Highlights: • Neutral beam prompt losses place appreciable power on an in-vessel tokamak antenna. • Simulations predict prompt loss power and inform protective tile design. • Experiments confirm the validity of the prompt loss simulations. - Abstract: Neutral beam prompt losses (injected neutrals that ionize such that their first poloidal transit intersects with the wall) can put appreciable power on the outer wall of tokamaks, and this power may damage the wall or other internal components. These prompt losses are simulated including a protruding helicon antenna installation in the DIII-D tokamak and it is determined that 160 kW of power will impact the antenna during the injection of a particular neutral beam. Protective graphite tiles are designed in response to this modeling and the wall shape of the installed antenna is precisely measured to improve the accuracy of these calculations. Initial experiments confirm that the antenna component temperature increases according to the amount of neutral beam energy injected into the plasma. In this case, only injection of beams that are aimed counter to the plasma current produce an appreciable power load on the outer wall, suggesting that the effect is of little concern for tokamaks featuring only co-current neutral beam injection. Incorporating neutral beam prompt loss considerations into the design of this in-vessel component serves to ensure that adequate protection or cooling is provided.

  8. Consideration of neutral beam prompt loss in the design of a tokamak helicon antenna

    Energy Technology Data Exchange (ETDEWEB)

    Pace, D.C., E-mail: pacedc@fusion.gat.com; Van Zeeland, M.A.; Fishler, B.; Murphy, C.

    2016-11-15

    Highlights: • Neutral beam prompt losses place appreciable power on an in-vessel tokamak antenna. • Simulations predict prompt loss power and inform protective tile design. • Experiments confirm the validity of the prompt loss simulations. - Abstract: Neutral beam prompt losses (injected neutrals that ionize such that their first poloidal transit intersects with the wall) can put appreciable power on the outer wall of tokamaks, and this power may damage the wall or other internal components. These prompt losses are simulated including a protruding helicon antenna installation in the DIII-D tokamak and it is determined that 160 kW of power will impact the antenna during the injection of a particular neutral beam. Protective graphite tiles are designed in response to this modeling and the wall shape of the installed antenna is precisely measured to improve the accuracy of these calculations. Initial experiments confirm that the antenna component temperature increases according to the amount of neutral beam energy injected into the plasma. In this case, only injection of beams that are aimed counter to the plasma current produce an appreciable power load on the outer wall, suggesting that the effect is of little concern for tokamaks featuring only co-current neutral beam injection. Incorporating neutral beam prompt loss considerations into the design of this in-vessel component serves to ensure that adequate protection or cooling is provided.

  9. Energy Deposition in Adjacent LHC Superconducting Magnets from Beam Loss at LHC Transfer Line Collimators

    CERN Document Server

    Beavan, S; Kain, V

    2006-01-01

    Injection intensities for the LHC are over an order of magnitude above the damage threshold. The collimation system in the two transfer lines is designed to dilute the beam sufficiently to avoid damage in case of accidental beam loss or mis-steered beam. To maximise the protection for the LHC most of the collimators are located in the last 300 m upstream of the injection point where the transfer lines approach the LHC machine. To study the issue of possible quenches following beam loss at the collimators part of the collimation section in one of the lines, TI 8, together with the adjacent part of the LHC has been modeled in FLUKA. The simulated energy deposition in the LHC for worst-case accidental losses and as well as for losses expected during a normal filling is presented.

  10. Analog front end circuit design of CSNS beam loss monitor system

    International Nuclear Information System (INIS)

    Xiao Shuai; Guo Xian; Tian Jianmin; Zeng Lei; Xu Taoguang; Fu Shinian

    2013-01-01

    The China Spallation Neutron Source (CSNS) beam loss monitor system uses gas ionization chamber to detect beam losses. The output signals from ionization chamber need to be processed in the analog front end circuit, which has been designed and developed independently. The way of transimpedance amplifier was used to achieve current-voltage (I-V) conversion measurement of signal with low repetition rate, low duty cycle and low amplitude. The analog front end circuit also realized rapid response to the larger beam loss in order to protect the safe operation of the accelerator equipment. The testing results show that the analog front end circuit meets the requirements of beam loss monitor system. (authors)

  11. Design of the Beam Loss Monitoring System for the LHC Ring

    CERN Document Server

    Holzer, E B; Effinger, E; Ferioli, G; González, J L; Gschwendtner, E; Guaglio, Gianluca; Hodgson, M; Prieto, V; Zamantzas, C

    2004-01-01

    The beam loss monitoring (BLM) system of the LHC is one of the most critical elements for the protection of the LHC. It must prevent the super conducting magnets from quenches and the machine components from damages, caused by beam losses. It helps in the identification of the loss mechanism by measuring the loss pattern. Special detectors will be used for the setup and control of the collimators. Furthermore, it will be an important tool during machine setup and studies. The specification requirements of the BLM system include a very high reliability.

  12. Comparative test results of various beam loss monitors in preparation for LHC

    OpenAIRE

    Bosser, Jacques; Ferioli, G

    1999-01-01

    Beam loss detectors will play an important role in the protection of the superconducting LHC magnets. Different types of detectors have been tested in the SPS ring and secondary beam lines with a view to their possible use for this application. This paper describes the measurements made with: microcalorimeters at cryogenic temperatures, PIN diodes, ionisation chambers, scintillators, and ACEMs. Measurements made using proton beams showing their relative sensitivities, linearities in counting ...

  13. Reliability of Beam Loss Monitors System for the Large Hadron Collider

    CERN Document Server

    Guaglio, Gianluca; Santoni, C

    2004-01-01

    The employment of superconducting magnets, in the high energies colliders, opens challenging failure scenarios and brings new criticalities for the whole system protection. For the LHC beam loss protection system, the failure rate and the availability requirements have been evaluated using the Safety Integrity Level (SIL) approach. A downtime cost evaluation is used as input for the SIL approach. The most critical systems, which contribute to the final SIL value, are the dump system, the interlock system, the beam loss monitors system and the energy monitor system. The Beam Loss Monitors System (BLMS) is critical for short and intense particles losses, while at medium and higher loss time it is assisted by other systems, such as the quench protection system and the cryogenic system. For BLMS, hardware and software have been evaluated in detail. The reliability input figures have been collected using historical data from the SPS, using temperature and radiation damage experimental data as well as using standar...

  14. Basis for low beam loss in the high-current APT linac

    International Nuclear Information System (INIS)

    Wangler, T.P.; Gray, E.R.; Krawczyk, F.L.; Kurennoy, S.S.; Lawrence, G.P.; Ryne, R.D.; Crandall, K.R.

    1998-01-01

    The present evidence that the APT proton linac design will meet its goal of low beam loss operation. The conclusion has three main bases: (1) extrapolation from the understanding of the performance of the 800-MeV LANSCE proton linac at Los Alamos, (2) the theoretical understanding of the dominant halo-forming mechanism in the APT accelerator from physics models and multiparticle simulations, and (3) the conservative approach and key principles underlying the design of the APT linac, which are aimed at minimizing beam halo and providing large apertures to reduce beam loss to a very low value

  15. Beam losses due to abrupt crab cavity failures in the LHC

    International Nuclear Information System (INIS)

    Baer, T.; Barranco, J.; Calaga, R.; Tomas, R.; Wenninger, B.; Yee, B.; Zimmermann, F.

    2011-01-01

    A major concern for the implementation of crab crossing in a future High-Luminosity LHC (HL-LHC) is machine protection in an event of a fast crab-cavity failure. Certain types of abrupt crab-cavity amplitude and phase changes are simulated to characterize the effect of failures on the beam and the resulting particle-loss signatures. The time-dependent beam loss distributions around the ring and particle trajectories obtained from the simulations allow for a first assessment of the resulting beam impact on LHC collimators and on sensitive components around the ring. Results for the nominal LHC lattice is presented.

  16. On the validity of localized approximation for an on-axis zeroth-order Bessel beam

    International Nuclear Information System (INIS)

    Gouesbet, Gérard; Lock, J.A.; Ambrosio, L.A.; Wang, J.J.

    2017-01-01

    Localized approximation procedures are efficient ways to evaluate beam shape coefficients of laser beams, and are particularly useful when other methods are ineffective or inefficient. Several papers in the literature have reported the use of such procedures to evaluate the beam shape coefficients of Bessel beams. Examining the specific case of an on-axis zeroth-order Bessel beam, we demonstrate that localized approximation procedures are valid only for small axicon angles. - Highlights: • The localized approximation has been widely used to evaluate the Beam Shape Coefficients (BSCs) of Bessel beams. • The validity of this approximation is examined in the case of an on-axis zeroth-order Bessel beam. • It is demonstrated, in this specific example, that the localized approximation is efficient only for small enough axicon angles. • It is easily argued that this result must remain true for any kind of Bessel beams.

  17. Severe signal loss in diamond beam loss monitors in high particle rate environments by charge trapping in radiation-induced defects

    CERN Document Server

    Kassel, Florian; Dabrowski, Anne; de Boer, Wim

    2016-01-01

    The beam condition monitoring leakage (BCML) system is a beam monitoring device in the compact muon solenoid (CMS) experiment at the large hadron collider (LHC). As detectors 32 poly-crystalline (pCVD) diamond sensors are positioned in rings around the beam pipe. Here, high particle rates occur from the colliding beams scattering particles outside the beam pipe. These particles cause defects, which act as traps for the ionization, thus reducing the charge collection efficiency (CCE). However, the loss in CCE was much more severe than expected from low rate laboratory measurements and simulations, especially in single-crystalline (sCVD) diamonds, which have a low initial concentration of defects. The reason why in real experiments the CCE is much worse than in laboratory experiments is related to the ionization rate. At high particle rates the trapping rate of the ionization is so high compared with the detrapping rate, that space charge builds up. This space charge reduces locally the internal electric field,...

  18. Energy loss of a high charge bunched electron beam in plasma: Simulations, scaling, and accelerating wakefields

    Directory of Open Access Journals (Sweden)

    J. B. Rosenzweig

    2004-06-01

    Full Text Available The energy loss and gain of a beam in the nonlinear, “blowout” regime of the plasma wakefield accelerator, which features ultrahigh accelerating fields, linear transverse focusing forces, and nonlinear plasma motion, has been asserted, through previous observations in simulations, to scale linearly with beam charge. Additionally, from a recent analysis by Barov et al., it has been concluded that for an infinitesimally short beam, the energy loss is indeed predicted to scale linearly with beam charge for arbitrarily large beam charge. This scaling is predicted to hold despite the onset of a relativistic, nonlinear response by the plasma, when the number of beam particles occupying a cubic plasma skin depth exceeds that of plasma electrons within the same volume. This paper is intended to explore the deviations from linear energy loss using 2D particle-in-cell simulations that arise in the case of experimentally relevant finite length beams. The peak accelerating field in the plasma wave excited behind the finite-length beam is also examined, with the artifact of wave spiking adding to the apparent persistence of linear scaling of the peak field amplitude into the nonlinear regime. At large enough normalized charge, the linear scaling of both decelerating and accelerating fields collapses, with serious consequences for plasma wave excitation efficiency. Using the results of parametric particle-in-cell studies, the implications of these results for observing severe deviations from linear scaling in present and planned experiments are discussed.

  19. Reliability of Beam Loss Monitor Systems for the Large Hadron Collider

    International Nuclear Information System (INIS)

    Guaglio, G.; Dehning, B.; Santoni, C.

    2005-01-01

    The increase of beam energy and beam intensity, together with the use of super conducting magnets, opens new failure scenarios and brings new criticalities for the whole accelerator protection system. For the LHC beam loss protection system, the failure rate and the availability requirements have been evaluated using the Safety Integrity Level (SIL) approach. A downtime cost evaluation is used as input for the SIL approach. The most critical systems, which contribute to the final SIL value, are the dump system, the interlock system, the beam loss monitors system, and the energy monitor system. The Beam Loss Monitors System (BLMS) is critical for short and intense particles losses at 7 TeV and assisted by the Fast Beam Current Decay Monitors at 450 GeV. At medium and higher loss time it is assisted by other systems, such as the quench protection system and the cryogenic system. For BLMS, hardware and software have been evaluated in detail. The reliability input figures have been collected using historical data from the SPS, using temperature and radiation damage experimental data as well as using standard databases. All the data has been processed by reliability software (Isograph). The analysis spaces from the components data to the system configuration

  20. Reliability of Beam Loss Monitor Systems for the Large Hadron Collider

    CERN Document Server

    Guaglio, Gianluca; Santoni, C

    2005-01-01

    The increase of beam energy and beam intensity, together with the use of super conducting magnets, opens new failure scenarios and brings new criticalities for the whole accelerator protection system. For the LHC beam loss protection system, the failure rate and the availability requirements have been evaluated using the Safety Integrity Level (SIL) approach. A downtime cost evaluation is used as input for the SIL approach. The most critical systems, which contribute to the final SIL value, are the dump system, the interlock system, the beam loss monitors system, and the energy monitor system. The Beam Loss Monitors System (BLMS) is critical for short and intense particles losses at 7 TeV and assisted by the Fast Beam Current Decay Monitors at 450 GeV. At medium and higher loss time it is assisted by other systems, such as the quench protection system and the cryogenic system. For BLMS, hardware and software have been evaluated in detail. The reliability input figures have been collected using historical data...

  1. Reliability of Beam Loss Monitor Systems for the Large Hadron Collider

    Science.gov (United States)

    Guaglio, G.; Dehning, B.; Santoni, C.

    2005-06-01

    The increase of beam energy and beam intensity, together with the use of super conducting magnets, opens new failure scenarios and brings new criticalities for the whole accelerator protection system. For the LHC beam loss protection system, the failure rate and the availability requirements have been evaluated using the Safety Integrity Level (SIL) approach. A downtime cost evaluation is used as input for the SIL approach. The most critical systems, which contribute to the final SIL value, are the dump system, the interlock system, the beam loss monitors system, and the energy monitor system. The Beam Loss Monitors System (BLMS) is critical for short and intense particles losses at 7 TeV and assisted by the Fast Beam Current Decay Monitors at 450 GeV. At medium and higher loss time it is assisted by other systems, such as the quench protection system and the cryogenic system. For BLMS, hardware and software have been evaluated in detail. The reliability input figures have been collected using historical data from the SPS, using temperature and radiation damage experimental data as well as using standard databases. All the data has been processed by reliability software (Isograph). The analysis spaces from the components data to the system configuration.

  2. The upgraded data acquisition system for beam loss monitoring at the Fermilab Tevatron and Main Injector

    International Nuclear Information System (INIS)

    Baumbaugh, A.; Briegel, C.; Brown, B.C.; Capista, D.; Drennan, C.; Fellenz, B.; Knickerbocker, K.; Lewis, J.D.; Marchionni, A.; Needles, C.; Olson, M.

    2011-01-01

    A VME-based data acquisition system for beam-loss monitors has been developed and is in use in the Tevatron and Main Injector accelerators at the Fermilab complex. The need for enhanced beam-loss protection when the Tevatron is operating in collider-mode was the main driving force for the new design. Prior to the implementation of the present system, the beam-loss monitor system was disabled during collider operation and protection of the Tevatron magnets relied on the quench protection system. The new Beam-Loss Monitor system allows appropriate abort logic and thresholds to be set over the full set of collider operating conditions. The system also records a history of beam-loss data prior to a beam-abort event for post-abort analysis. Installation of the Main Injector system occurred in the fall of 2006 and the Tevatron system in the summer of 2007. Both systems were fully operation by the summer of 2008. In this paper we report on the overall system design, provide a description of its normal operation, and show a number of examples of its use in both the Main Injector and Tevatron.

  3. Beam size blow-up and current loss in the Fermilab Main Ring during storage

    International Nuclear Information System (INIS)

    Guignard, C.; Month, M.

    1977-01-01

    Observations at Fermilab during storage mode operation show characteristic forms of transverse beam size growth and current loss with time. There are three obvious mechanisms which can produce such blowup. The gas pressure is a source for immediate beam loss by direct nuclear scattering. Protons can also multiple scatter off the orbiting electrons of the gas atoms causing the trasnverse beam size to increase with time. A third mechanism not related to gas pressure is beam growth due to multiple crossing of betatron resonances arising from the synchrotron oscillations of the stored bunches. This simulates a random walk and causes the transverse beam size to grow. This is an attempt to describe the observations with direct nuclear scattering, multiple coulomb scattering, and multiple resonance crossing

  4. Design and performance of the beam loss monitor system for the Advanced Photon Source

    International Nuclear Information System (INIS)

    Patterson, D.

    1994-01-01

    The design of the beam loss monitor system for the Argonne National Laboratory Advanced Photon Source is based on using a number of air dielectric coaxial cables as long ionization chambers. The coaxial cables are multiplexed into a high sensitivity DC current-to-voltage converter, which provides an output proportional to the average loss rate over the length of the multiplexed cable. Losses of sufficient amplitude generate measurable voltage pulses on the coaxial cable at a location near the loss point. Multiplexed pulse timing circuits determine the location of the losses by measuring the time at which these voltage pulses arrive at the beginning of the coaxial cable. The loss monitor system has been tested on the SPEAR accelerator at SSRL and was demonstrated to be as sensitive as the DCCT. Preliminary performance data from the APS injector show that the sensitivities of the current-to-voltage, converter circuit are about ten picoamperes of loss monitor signal per picocoulomb per second beam loss rate. The corresponding pulse sensitivity is about 28 μV pulse amplitude in the coaxial cable per picocoulomb of loss. Both these sensitivities are at 300-MeV beam energies. The loss monitor has proven useful in initial commissioning of the injector. Further data will be available as accelerator construction and commissioning continue

  5. An approach to fundamental study of beam loss minimization

    International Nuclear Information System (INIS)

    Jameson, R.A.

    1999-01-01

    The accelerator design rules involving rms matching, developed at CERN in the 1970's, are discussed. An additional rule, for equipartitioning the beam energy among its degrees of freedom, may be added to insure an rms equilibrium conditions. If the strong stochasticity threshold is avoided, as it is in realistic accelerator designs, the dynamics is characterized by extremely long transient settling times, making the role of equipartitioning hard to explain. An approach to systematic study using the RFQ accelerator as a simulation testbed is discussed. New methods are available from recent advances in research on complexity, nonlinear dynamics, and chaos

  6. Prestress Loss of CFL in a Prestressing Process for Strengthening RC Beams

    Directory of Open Access Journals (Sweden)

    Xinyan Guo

    2017-01-01

    Full Text Available A prestressing system was designed to strengthen reinforced concrete (RC beams with prestressed carbon fiber laminate (CFL. During different prestressing processes, prestress loss was measured using strain gauges attached on the surface of CFL along the length direction. The prestress loss was 50–68% of the whole prestress loss, which is typically associated with CFL slipping between the grip anchors. Approximately 20–27% of the prestress loss was caused by the elastic shortening of the RC beam. An analytical model using linear-elastic theory was constructed to calculate the prestress loss caused by CFL slipping between the anchors and the elastic shortening of the strengthened beams. The compared results showed that the analytical model of prestress loss can describe the experimental data well. Methods of reducing the prestress loss were also suggested. Compared to other experiments, the prestressing system proposed by this research group was effective because the maximum percentage of prestress loss was 14.9% and the average prestress loss was 12.5%.

  7. Beam loss studies in high-intensity heavy-ion linacs

    International Nuclear Information System (INIS)

    Ostroumov, P.N.; Aseev, V.N.; Lessner, E.S.; Mustapha, B.

    2004-01-01

    A low beam-loss budget is an essential requirement for high-intensity machines and represents one of their major design challenges. In a high-intensity heavy-ion machine, losses are required to be below 1 W/m for hands-on-maintenance. The driver linac of the Rare Isotope Accelerator (RIA) is designed to accelerate beams of any ion to energies from 400 MeV per nucleon for uranium up to 950 MeV for protons with a beam power of up to 400 kW. The high intensity of the heaviest ions is achieved by acceleration of multiple-charge-state beams, which requires a careful beam dynamics optimization to minimize effective emittance growth and beam halo formation. For beam loss simulation purposes, large number of particles must be tracked through the linac. Therefore the computer code TRACK has been parallelized and calculations are being performed on the JAZZ cluster recently inaugurated at ANL. This paper discusses how this powerful tool is being used for simulations for the RIA project to help decide on the high-performance and cost-effective design of the driver linac

  8. Off-momentum loss maps with one beam

    CERN Document Server

    Garcia Morales, Hector; Salvachua Ferrando, Belen Maria; CERN. Geneva. ATS Department

    2016-01-01

    The aim of this MD is the benchmarking of simulation of off-momentum loss maps. This will help us to further understand the dynamics of the off-momentum collimation cleaning and give input to the determination of the operational settings of the off-momentum cleaning insertion. The MD was carried out during different end-of-fills of other MDs. In this note we summarize the procedures and the measurements taken during the MD week.

  9. Measurement of transepidermal water loss in localized scleroderma.

    Science.gov (United States)

    Ďurčanská, Veronika; Jedličková, Hana; Vašků, Vladimír

    2016-05-01

    Localized scleroderma (LS) is a disease characterized by fibrotic changes in the dermis. Connective tissue growth factor and transforming growth factor β2 are the main mediators of fibrogenesis; this, along with excessive connective tissue production, affects epidermal keratinocytes, and thereby contributes to the changed quality of skin barrier. The objective of this article was to study the objective measurement of the skin barrier quality in LS with transepidermal water loss (TEWL) meter. The measurements of TEWL were performed on LS plaques in all three stages of various body locations. Control measurements were made on the contralateral side of healthy skin. The difference between TEWL in LS area and the contralateral side of the healthy skin was evaluated. A higher average TEWL 7.86 g/m(2) /h (SD 5.29) was observed on LS plaques compared with the control measurements on healthy skin 6.39 g/m(2) /h (SD 2.77). TEWL average values decreased from the inflammatory stage, through the sclerotic and to the atrophic stage. The mean difference 1.301 g/m(2) /h (SD 5.16) was found between TEWL on LS plaques and on the contralateral healthy skin in 82 measurements, i.e., a higher TEWL was observed in LS. The difference was statistically significant with p = 0.0250. Although fibrogenesis in scleroderma is localized in dermis, the skin barrier changes can be detected. © 2016 Wiley Periodicals, Inc.

  10. Simulation study on beam loss in the alpha bucket regime during SIS-100 proton operation

    Science.gov (United States)

    Sorge, S.

    2018-02-01

    Crossing the transition energy γt in synchrotrons for high intensity proton beams requires well tuned jump schemes and is usually accompanied by longitudinal emittance growth. In order to avoid γt crossing during proton operation in the projected SIS-100 synchrotron special high-γt lattice settings have been developed, in order to keep γt above the beam extraction energy. A further advantage of this scheme is the formation of alpha buckets which naturally lead to short proton bunches, required for the foreseen production and storage of antiprotons for the FAIR facility. Special attention is turned on the imperfections of the superconducting SIS-100 magnets because together with the high-γt lattice settings, they could potentially lead to enhanced beam loss. The aim of the present work is to estimate the beam loss by means of particle tracking simulations.

  11. Study of Acquisition Electronics with a High Dynamic Range for a Beam Loss Measurement System

    CERN Document Server

    Venturini, G; Dehning, B; Effinger, E

    2010-01-01

    The particles accelerated in CERN accelerator chain reach high energies, topped by the particle energy at collision in the LHC, 7 GeV. During the operation, an amount of particles is inevitably lost from the beam. Depending on the extent of the losses, physical damage to machine components may be caused and the shower of secondary emission particles deposits energy in the surrounding equipment constituting the accelerator. The hadronic cascade also activates their materials, representing a hazard to the workers at CERN. In the LHC, the superconducting magnets that constitute the synchrotron lattice are kept at an operating temperature of 1:9K through a cryogenic facility employing superliquid helium, the increase in their temperature potentially initiates a quench. In the SPS, the damage due to a lost beam is also visible. The Beam Loss Monitoring (BLM) system has been developed to reliably protect the machines composing CERN’s accelerator chain and additionally provide information about the beam status: th...

  12. Cooling equilibrium and beam loss with internal targets in high energy storage rings

    International Nuclear Information System (INIS)

    Boine-Frankenheim, O.; Hasse, R.; Hinterberger, F.; Lehrach, A.; Zenkevich, P.

    2006-01-01

    The beam cooling equilibrium with internal target interaction is analyzed for parameters relevant to the proposed High Energy Storage Ring (HESR). For the proposed experiments with anti-protons high luminosities together with low momentum spreads are required. Rate equations are used to predict the rms equilibrium beam parameters. The cooling and IBS rate coefficients are obtained from simplified models. Energy loss straggling in the target and the associated beam loss are analyzed analytically assuming a thin target. A longitudinal kinetic simulation code is used to study the evolution of the momentum distribution in coasting and bunched beams. Analytic expressions for the target induced momentum tail are found in good agreement with the simulation results

  13. Measured and simulated heavy-ion beam loss patterns at the CERN Large Hadron Collider

    Science.gov (United States)

    Hermes, P. D.; Bruce, R.; Jowett, J. M.; Redaelli, S.; Salvachua Ferrando, B.; Valentino, G.; Wollmann, D.

    2016-05-01

    The Large Hadron Collider (LHC) at CERN pushes forward to new regimes in terms of beam energy and intensity. In view of the combination of very energetic and intense beams together with sensitive machine components, in particular the superconducting magnets, the LHC is equipped with a collimation system to provide protection and intercept uncontrolled beam losses. Beam losses could cause a superconducting magnet to quench, or in the worst case, damage the hardware. The collimation system, which is optimized to provide a good protection with proton beams, has shown a cleaning efficiency with heavy-ion beams which is worse by up to two orders of magnitude. The reason for this reduced cleaning efficiency is the fragmentation of heavy-ion beams into isotopes with a different mass to charge ratios because of the interaction with the collimator material. In order to ensure sufficient collimation performance in future ion runs, a detailed theoretical understanding of ion collimation is needed. The simulation of heavy-ion collimation must include processes in which 82 + 208Pb ions fragment into dozens of new isotopes. The ions and their fragments must be tracked inside the magnetic lattice of the LHC to determine their loss positions. This paper gives an overview of physical processes important for the description of heavy-ion loss patterns. Loss maps simulated by means of the two tools ICOSIM [1,2] and the newly developed STIER (SixTrack with Ion-Equivalent Rigidities) are compared with experimental data measured during LHC operation. The comparison shows that the tool STIER is in better agreement.

  14. Simulations and measurements of beam loss patterns at the CERN Large Hadron Collider

    Science.gov (United States)

    Bruce, R.; Assmann, R. W.; Boccone, V.; Bracco, C.; Brugger, M.; Cauchi, M.; Cerutti, F.; Deboy, D.; Ferrari, A.; Lari, L.; Marsili, A.; Mereghetti, A.; Mirarchi, D.; Quaranta, E.; Redaelli, S.; Robert-Demolaize, G.; Rossi, A.; Salvachua, B.; Skordis, E.; Tambasco, C.; Valentino, G.; Weiler, T.; Vlachoudis, V.; Wollmann, D.

    2014-08-01

    The CERN Large Hadron Collider (LHC) is designed to collide proton beams of unprecedented energy, in order to extend the frontiers of high-energy particle physics. During the first very successful running period in 2010-2013, the LHC was routinely storing protons at 3.5-4 TeV with a total beam energy of up to 146 MJ, and even higher stored energies are foreseen in the future. This puts extraordinary demands on the control of beam losses. An uncontrolled loss of even a tiny fraction of the beam could cause a superconducting magnet to undergo a transition into a normal-conducting state, or in the worst case cause material damage. Hence a multistage collimation system has been installed in order to safely intercept high-amplitude beam protons before they are lost elsewhere. To guarantee adequate protection from the collimators, a detailed theoretical understanding is needed. This article presents results of numerical simulations of the distribution of beam losses around the LHC that have leaked out of the collimation system. The studies include tracking of protons through the fields of more than 5000 magnets in the 27 km LHC ring over hundreds of revolutions, and Monte Carlo simulations of particle-matter interactions both in collimators and machine elements being hit by escaping particles. The simulation results agree typically within a factor 2 with measurements of beam loss distributions from the previous LHC run. Considering the complex simulation, which must account for a very large number of unknown imperfections, and in view of the total losses around the ring spanning over 7 orders of magnitude, we consider this an excellent agreement. Our results give confidence in the simulation tools, which are used also for the design of future accelerators.

  15. Simulations and measurements of beam loss patterns at the CERN Large Hadron Collider

    Directory of Open Access Journals (Sweden)

    R. Bruce

    2014-08-01

    Full Text Available The CERN Large Hadron Collider (LHC is designed to collide proton beams of unprecedented energy, in order to extend the frontiers of high-energy particle physics. During the first very successful running period in 2010–2013, the LHC was routinely storing protons at 3.5–4 TeV with a total beam energy of up to 146 MJ, and even higher stored energies are foreseen in the future. This puts extraordinary demands on the control of beam losses. An uncontrolled loss of even a tiny fraction of the beam could cause a superconducting magnet to undergo a transition into a normal-conducting state, or in the worst case cause material damage. Hence a multistage collimation system has been installed in order to safely intercept high-amplitude beam protons before they are lost elsewhere. To guarantee adequate protection from the collimators, a detailed theoretical understanding is needed. This article presents results of numerical simulations of the distribution of beam losses around the LHC that have leaked out of the collimation system. The studies include tracking of protons through the fields of more than 5000 magnets in the 27 km LHC ring over hundreds of revolutions, and Monte Carlo simulations of particle-matter interactions both in collimators and machine elements being hit by escaping particles. The simulation results agree typically within a factor 2 with measurements of beam loss distributions from the previous LHC run. Considering the complex simulation, which must account for a very large number of unknown imperfections, and in view of the total losses around the ring spanning over 7 orders of magnitude, we consider this an excellent agreement. Our results give confidence in the simulation tools, which are used also for the design of future accelerators.

  16. Beam size blow-up and current loss in the Fermilab main ring during storage

    International Nuclear Information System (INIS)

    Guignard, G.; Month, M.

    1977-01-01

    Observations at Fermilab during the storage mode of operation show characteristic forms of transverse beam size growth and current loss with time. There are three obvious mechanisms which can produce such blowup. The gas pressure is a source for immediate beam loss by direct nuclear scattering. Protons can also multiple Coulomb scatter off the orbiting electrons of the gas atoms causing the transverse beam size to increase with time, t. This effect is therefore also proportional to the gas pressure. A third mechanism not related to the gas pressure is beam growth due to multiple crossing of betatron resonances arising from the synchrotron oscillations of the stored bunches. This simulates a random walk and causes the transverse beam size to grow with √t. An attempt is made to describe the observations with direct nuclear scattering, multiple coulomb scattering and multiple resonance crossing. In addition to the loss rate from direct nuclear scattering, the presence of betatron resonances also contribute to particle loss. In fact this latter effect becomes dominant after the beam size reaches a critical value. This critical size is referred to as the resonance aperture. It is the size at which ''fast'' resonance crossing is no longer valid. The stopband width becomes so large (due both to emittance growth as well as the increase in magnetic field distortions) that particles are locked into the resonance and are extracted to the physical aperture. The model is described in a phenomenological way, and the coefficients involved are estimated. Theoretical curves for transverse beam growth and loss rate are plotted and compared with some measured values. Finally, some general comments are given

  17. Simulations and measurements of beam loss patterns at the CERN Large Hadron Collider

    CERN Document Server

    Bruce, R.; Boccone, V.; Bracco, C.; Brugger, M.; Cauchi, M.; Cerutti, F.; Deboy, D.; Ferrari, A.; Lari, L.; Marsili, A.; Mereghetti, A.; Mirarchi, D.; Quaranta, E.; Redaelli, S.; Robert-Demolaize, G.; Rossi, A.; Salvachua, B.; Skordis, E.; Tambasco, C.; Valentino, G.; Weiler, T.; Vlachoudis, V.; Wollmann, D.

    2014-08-21

    The CERN Large Hadron Collider (LHC) is designed to collide proton beams of unprecedented energy, in order to extend the frontiers of high-energy particle physics. During the first very successful running period in 2010--2013, the LHC was routinely storing protons at 3.5--4 TeV with a total beam energy of up to 146 MJ, and even higher stored energies are foreseen in the future. This puts extraordinary demands on the control of beam losses. An un-controlled loss of even a tiny fraction of the beam could cause a superconducting magnet to undergo a transition into a normal-conducting state, or in the worst case cause material damage. Hence a multi-stage collimation system has been installed in order to safely intercept high-amplitude beam protons before they are lost elsewhere. To guarantee adequate protection from the collimators, a detailed theoretical understanding is needed. This article presents results of numerical simulations of the distribution of beam losses around the LHC that have leaked out of the co...

  18. Beam loss studies on silicon strip detector modules for the CMS experiment

    CERN Document Server

    Fahrer, Manuel

    2006-01-01

    The large beam energy of the LHC demands for a save beam abort system. Nevertheless, failures cannot be excluded with last assurance and are predicted to occur once per year. As the CMS experiment is placed in the neighboured LHC octant, it is affected by such events. The effect of an unsynchronized beam abort on the silicon strip modules of the CMS tracking detector has been investigated in this thesis by performing one accelerator and two lab experiments. The dynamical behaviour of operational parameters of modules and components has been recorded during simulated beam loss events to be able to disentangle the reasons of possible damages. The first study with high intensive proton bunches at the CERN PS ensured the robustness of the module design against beam losses. A further lab experiment with pulsed IR LEDs clarified the physical and electrical processes during such events. The silicon strip sensors on a module are protected against beam losses by a part of the module design that originally has not been...

  19. Anomalous Beam-Ion Loss in TFTR Reversed Magnetic Shear Plasmas

    International Nuclear Information System (INIS)

    Ruskov, E.; Bell, M.; Budny, R.V.; McCune, D.C.; Medley, S.S.; Redi, M.H.; Scott, S.; Synakowski, E.J.; Goeler, S. von; White, R.B.; Zweben, S.J.

    1999-01-01

    Anomalous beam-ion loss has been observed in an experiment with short tritium beam pulses injected into deuterium-beam-heated Tokamak Fusion Test Reactor plasmas (P NBI =15 MW) with reversed magnetic shear (RS). Comparisons of the measured total 14thinspthinspMeV neutron emission, the neutron flux along eight radial locations, and the perpendicular plasma stored energy with predictions from an extensive set of TRANSP simulations suggest that about 40% beam power is lost on a time scale much shorter than the tritium beam pulse length Δt=70 ms. In contrast with recent results [K. Tobita et al., Nucl.Fusion 37, 1583 (1997)] from RS experiments at JT-60U, we were not able to show conclusively that magnetic field ripple is responsible for this anomaly. copyright 1999 The American Physical Society

  20. On the dynamics of Airy beams in nonlinear media with nonlinear losses.

    Science.gov (United States)

    Ruiz-Jiménez, Carlos; Nóbrega, K Z; Porras, Miguel A

    2015-04-06

    We investigate on the nonlinear dynamics of Airy beams in a regime where nonlinear losses due to multi-photon absorption are significant. We identify the nonlinear Airy beam (NAB) that preserves the amplitude of the inward Hänkel component as an attractor of the dynamics. This attractor governs also the dynamics of finite-power (apodized) Airy beams, irrespective of the location of the entrance plane in the medium with respect to the Airy waist plane. A soft (linear) input long before the waist, however, strongly speeds up NAB formation and its persistence as a quasi-stationary beam in comparison to an abrupt input at the Airy waist plane, and promotes the formation of a new type of highly dissipative, fully nonlinear Airy beam not described so far.

  1. New results on the beam-loss criteria for heavy-ion accelerators

    International Nuclear Information System (INIS)

    Katrik, Peter; Hoffmann, Dieter H.H.; Mustafin, Edil; Strasik, Ivan; Pavlovic, Marius

    2015-01-01

    Activation of high-energy heavy-ion accelerators due to beam losses is a serious issue for accelerator parts like collimators, magnets, beam-lines, fragment separator targets, etc. The beam losses below 1 W/m are considered as tolerable for 'hands-on' maintenance in proton machines. In our previous studies, the FLUKA2008 code has been used for establishing a scaling law expanding the existing beam-loss tolerance for 1 GeV protons to heavy ions. This scaling law enabled specifying beam-loss criteria for projectile species from proton up to uranium at energies from 200 MeV/u up to 1 GeV/u. FLUKA2008 allowed nucleus-nucleus interactions down to 100 MeV/u only. In this work, we review our previous results and extend activation simulations to lower energies with the help of the new FLUKA version, namely FLUKA2011. It includes models for nucleus-nucleus interactions below 100 MeV/u. We also tried to expand the scaling law to lower energies. This, however, needs further studies, because the heavy-ion-induced nuclide composition starts deviating from the proton-induced nuclide composition at energies below 150 MeV/u. (authors)

  2. Comparison of measured and computed loss to parasitic modes in cylindrical cavities with beam ports

    International Nuclear Information System (INIS)

    Wilson, P.B.; Styles, J.B.; Bane, K.L.F.

    1977-03-01

    Good agreement was obtained between computed values and results from a bench measurement technique for the total loss to parasitic modes in several cylindrical cavities with beam ports. The measurement of loss as a function of time within the current pulse also gives results which are in good agreement with computed functions, especially considering the fact that there are questionable points concerning both the theory and the measurement technique. Within measurement errors, there is also agreement in a few cases where a comparison is possible between a bench measurement result and the heating produced directly in a component by the SPEAR beam

  3. On the validity of the use of a localized approximation for helical beams. I. Formal aspects

    Science.gov (United States)

    Gouesbet, Gérard; André Ambrosio, Leonardo

    2018-03-01

    The description of an electromagnetic beam for use in light scattering theories may be carried out by using an expansion over vector spherical wave functions with expansion coefficients expressed in terms of Beam Shape Coefficients (BSCs). A celebrated method to evaluate these BSCs has been the use of localized approximations (with several existing variants). We recently established that the use of any existing localized approximation is of limited validity in the case of Bessel and Mathieu beams. In the present paper, we address a warning against the use of any existing localized approximation in the case of helical beams. More specifically, we demonstrate that a procedure used to validate any existing localized approximation fails in the case of helical beams. Numerical computations in a companion paper will confirm that existing localized approximations are of limited validity in the case of helical beams.

  4. Loss of balance during balance beam walking elicits a multifocal theta band electrocortical response

    OpenAIRE

    Sipp, Amy R.; Gwin, Joseph T.; Makeig, Scott; Ferris, Daniel P.

    2013-01-01

    Determining the neural correlates of loss of balance during walking could lead to improved clinical assessment and treatment for individuals predisposed to falls. We used high-density electroencephalography (EEG) combined with independent component analysis (ICA) to study loss of balance during human walking. We examined 26 healthy young subjects performing heel-to-toe walking on a treadmill-mounted balance beam as well as walking on the treadmill belt (both at 0.22 m/s). ICA identified clust...

  5. Very Fast Losses of the Circulating LHC Beam, their Mitigation and Machine Protection

    CERN Document Server

    Baer, Tobias; Elsen, Eckhard

    The Large Hadron Collider (LHC) has a nominal energy of 362MJ stored in each of its two counter-rotating beams - over two orders of magnitude more than any previous accelerator and enough to melt 880kg of copper. Therefore, in case of abnormal conditions comprehensive machine protection systems extract the beams safely from the LHC within not more than three turns $\\approx$270$\\mu$s. The first years of LHC operation demonstrated a remarkable reliability of the major machine protection systems. However, they also showed that the LHC is vulnerable to losses of the circulating beams on very fast timescales, which are too fast to ensure an active protection. Very fast equipment failures, in particular of normal-conducting dipole magnets and the transverse damper can lead to such beam losses. Whereas these failures were already studied in the past, other unexpected beam loss mechanisms were observed after the LHC start-up: so-called (un)identified falling objects (UFOs), which are believed to be micrometer-sized m...

  6. Low loss power splitter for antenna beam forming networks using probes in a waveguide

    OpenAIRE

    Dich, Mikael; Mortensen, Mette Dahl

    1994-01-01

    The design of a low loss one-to-four power splitter suitable for beam forming networks in antenna arrays is presented. The power splitter is constructed of a shorted waveguide in which five coaxial probes are inserted. Methods for the design of the power splitter are presented together with an experimental verification

  7. Low loss power splitter for antenna beam forming networks using probes in a waveguide

    DEFF Research Database (Denmark)

    Dich, Mikael; Mortensen, Mette Dahl

    1994-01-01

    The design of a low loss one-to-four power splitter suitable for beam forming networks in antenna arrays is presented. The power splitter is constructed of a shorted waveguide in which five coaxial probes are inserted. Methods for the design of the power splitter are presented together...

  8. Design and Development of a Diagnostics Client for a Beam Loss Measurement System at CERN

    CERN Document Server

    Angelogiannopoulos, Emmanouil; Jackson, Stephen

    The European Organization for Nuclear Research, known as CERN, is one of the biggest research centers in the field of particle physics. Its main function is to provide particle accelerators and other infrastructure needed for high energy physics research. Particles are accelerated through a complex of accelerators and are brought into collision, in order to study the fundamental elements of matter and the forces acting between them. Of course, such complex and expensive machines need control and protection. For that purpose, a variety of different systems -hardware and/or software- is needed. One such system is the Beam Loss Monitoring (BLM) system of an accelerator. This kind of system is designed for measuring beam losses around an accelerator. An appropriate design of the BLM system and an appropriate location of the monitors enable a wide field of very useful beam diagnostics and machine protection possibilities. This thesis focuses on the design and development of a client application, which is realized ...

  9. Observations of neutral beam and ICRF tail ion losses due to Alfven modes in TFTR

    International Nuclear Information System (INIS)

    Darrow, D.S.; Zweben, S.J.; Chang, Z.

    1996-04-01

    Fast ion losses resulting from MHD modes at the Alfven frequency, such as the TAE, have been observed in TFTR. The modes have been driven both by neutral beam ions, at low B T , and by H-minority ICRF tail ions at higher B T . The measurements indicate that the loss rate varies linearly with the mode amplitude, and that the fast ion losses during the mode activity can be significant, e.g. up to 10% of the input power is lost in the worst case

  10. Loss of balance during balance beam walking elicits a multifocal theta band electrocortical response.

    Science.gov (United States)

    Sipp, Amy R; Gwin, Joseph T; Makeig, Scott; Ferris, Daniel P

    2013-11-01

    Determining the neural correlates of loss of balance during walking could lead to improved clinical assessment and treatment for individuals predisposed to falls. We used high-density electroencephalography (EEG) combined with independent component analysis (ICA) to study loss of balance during human walking. We examined 26 healthy young subjects performing heel-to-toe walking on a treadmill-mounted balance beam as well as walking on the treadmill belt (both at 0.22 m/s). ICA identified clusters of electrocortical EEG sources located in or near anterior cingulate, anterior parietal, superior dorsolateral-prefrontal, and medial sensorimotor cortex that exhibited significantly larger mean spectral power in the theta band (4-7 Hz) during walking on the balance beam compared with treadmill walking. Left and right sensorimotor cortex clusters produced significantly less power in the beta band (12-30 Hz) during walking on the balance beam compared with treadmill walking. For each source cluster, we also computed a normalized mean time/frequency spectrogram time locked to the gait cycle during loss of balance (i.e., when subjects stepped off the balance beam). All clusters except the medial sensorimotor cluster exhibited a transient increase in theta band power during loss of balance. Cluster spectrograms demonstrated that the first electrocortical indication of impending loss of balance occurred in the left sensorimotor cortex at the transition from single support to double support prior to stepping off the beam. These findings provide new insight into the neural correlates of walking balance control and could aid future studies on elderly individuals and others with balance impairments.

  11. Reliability of Beam Loss Monitors System for the Large Hadron Collider

    Science.gov (United States)

    Guaglio, G.; Dehning, B.; Santoni, C.

    2004-11-01

    The employment of superconducting magnets in high energy colliders opens challenging failure scenarios and brings new criticalities for the whole system protection. For the LHC beam loss protection system, the failure rate and the availability requirements have been evaluated using the Safety Integrity Level (SIL) approach. A downtime cost evaluation is used as input for the SIL approach. The most critical systems, which contribute to the final SIL value, are the dump system, the interlock system, the beam loss monitors system and the energy monitor system. The Beam Loss Monitors System (BLMS) is critical for short and intense particle losses, while at medium and higher loss time it is assisted by other systems, such as the quench protection system and the cryogenic system. For BLMS, hardware and software have been evaluated in detail. The reliability input figures have been collected using historical data from the SPS, using temperature and radiation damage experimental data as well as using standard databases. All the data have been processed by reliability software (Isograph). The analysis ranges from the components data to the system configuration.

  12. Reliability of Beam Loss Monitors System for the Large Hadron Collider

    International Nuclear Information System (INIS)

    Guaglio, G.; Dehning, B.; Santoni, C.

    2004-01-01

    The employment of superconducting magnets in high energy colliders opens challenging failure scenarios and brings new criticalities for the whole system protection. For the LHC beam loss protection system, the failure rate and the availability requirements have been evaluated using the Safety Integrity Level (SIL) approach. A downtime cost evaluation is used as input for the SIL approach. The most critical systems, which contribute to the final SIL value, are the dump system, the interlock system, the beam loss monitors system and the energy monitor system. The Beam Loss Monitors System (BLMS) is critical for short and intense particle losses, while at medium and higher loss time it is assisted by other systems, such as the quench protection system and the cryogenic system. For BLMS, hardware and software have been evaluated in detail. The reliability input figures have been collected using historical data from the SPS, using temperature and radiation damage experimental data as well as using standard databases. All the data have been processed by reliability software (Isograph). The analysis ranges from the components data to the system configuration

  13. FLUKA Monte Carlo simulations and benchmark measurements for the LHC beam loss monitors

    International Nuclear Information System (INIS)

    Sarchiapone, L.; Brugger, M.; Dehning, B.; Kramer, D.; Stockner, M.; Vlachoudis, V.

    2007-01-01

    One of the crucial elements in terms of machine protection for CERN's Large Hadron Collider (LHC) is its beam loss monitoring (BLM) system. On-line loss measurements must prevent the superconducting magnets from quenching and protect the machine components from damages due to unforeseen critical beam losses. In order to ensure the BLM's design quality, in the final design phase of the LHC detailed FLUKA Monte Carlo simulations were performed for the betatron collimation insertion. In addition, benchmark measurements were carried out with LHC type BLMs installed at the CERN-EU high-energy Reference Field facility (CERF). This paper presents results of FLUKA calculations performed for BLMs installed in the collimation region, compares the results of the CERF measurement with FLUKA simulations and evaluates related uncertainties. This, together with the fact that the CERF source spectra at the respective BLM locations are comparable with those at the LHC, allows assessing the sensitivity of the performed LHC design studies

  14. FLUKA Monte Carlo simulations and benchmark measurements for the LHC beam loss monitors

    Science.gov (United States)

    Sarchiapone, L.; Brugger, M.; Dehning, B.; Kramer, D.; Stockner, M.; Vlachoudis, V.

    2007-10-01

    One of the crucial elements in terms of machine protection for CERN's Large Hadron Collider (LHC) is its beam loss monitoring (BLM) system. On-line loss measurements must prevent the superconducting magnets from quenching and protect the machine components from damages due to unforeseen critical beam losses. In order to ensure the BLM's design quality, in the final design phase of the LHC detailed FLUKA Monte Carlo simulations were performed for the betatron collimation insertion. In addition, benchmark measurements were carried out with LHC type BLMs installed at the CERN-EU high-energy Reference Field facility (CERF). This paper presents results of FLUKA calculations performed for BLMs installed in the collimation region, compares the results of the CERF measurement with FLUKA simulations and evaluates related uncertainties. This, together with the fact that the CERF source spectra at the respective BLM locations are comparable with those at the LHC, allows assessing the sensitivity of the performed LHC design studies.

  15. The LHC beam loss monitoring system's real-time data analysis card

    CERN Document Server

    Dehning, B; Ferioli, G; Guaglio, G; Leitner, R; Zamantzas, C

    2005-01-01

    The BLM (Beam Loss Monitoring) system has to prevent the superconducting magnets from being quenched and protect the machine components against damages making it one of the most critical elements for the protection of the LHC. The complete system consists of 3600 detectors, placed at various locations around the ring, tunnel electronics, which are responsible for acquiring, digitizing, and transmitting the data, and surface electronics, which receive the data via 2km optical data links, process, analyze, store, and issue warning and abort triggers. At those surface units, named BLMTCs, the backbone on each of them is an FPGA (field programmable gate array) which treats the loss signals collected from 16 detectors. It takes into account the beam energy and keeps 192 running sums giving loss durations of up to the last 84 seconds before it compares them with thresholds uniquely programmable for each detector. In this paper, the BLMTC's design is explored giving emphasis to the strategies followed in combining t...

  16. Knowledge Loss: Managing Local Knowledge in Rural Uzbekistan

    OpenAIRE

    Wall, Caleb; Evers, Hans-Dieter

    2006-01-01

    Knowledge loss is not a remote phenomenon, unique to one knowledge system. Rather we argue that the loss of knowledge is an issue for other knowledge systems as well. Knowledge loss is certainly a concern for anthropologists working on indigenous knowledge, fearful of ‘losing’ indigenous knowledge entirely as a result of modernisation (cf. Cox, 2000). Equally, staff movements within the corporate world probably lead to a large amount of knowledge displacement, yet staff (and thus knowledge) r...

  17. Beam losses from ultraperipheral nuclear collisions between ^{208}Pb^{82+} ions in the Large Hadron Collider and their alleviation

    Directory of Open Access Journals (Sweden)

    R. Bruce

    2009-07-01

    Full Text Available Electromagnetic interactions between colliding heavy ions at the Large Hadron Collider (LHC at CERN will give rise to localized beam losses that may quench superconducting magnets, apart from contributing significantly to the luminosity decay. To quantify their impact on the operation of the collider, we have used a three-step simulation approach, which consists of optical tracking, a Monte Carlo shower simulation, and a thermal network model of the heat flow inside a magnet. We present simulation results for the case of ^{208}Pb^{82+} ion operation in the LHC, with focus on the ALICE interaction region, and show that the expected heat load during nominal ^{208}Pb^{82+} operation is 40% above the quench level. This limits the maximum achievable luminosity. Furthermore, we discuss methods of monitoring the losses and possible ways to alleviate their effect.

  18. Studies of Limits on Uncontrolled Heavy Ion Beam Losses for Allowing Hands-On Maintenance. Final report

    International Nuclear Information System (INIS)

    Ronningen, Reginald M.; Remec, Igor

    2010-01-01

    Dose rates from accelerator components activated by 1 W/m beam losses are obtained semiempirically for a 1 GeV proton beam and by use of Monte Carlo transport codes for the proton beam and for 777 MeV/u 3He, 500 MeV/u 48Ca, 86Kr, 136Xe, and 400 MeV/u 238U ions. The dose rate obtained by the semi-empirical method, 0.99 mSv/h (99 mrem/h) at 30 cm, 4 h after 100 d irradiation by a 1-GeV proton beam, is consistent with studies at several accelerator facilities and with adopted hands-on maintenance dose rate limits. Monte Carlo simulations verify this result for protons and extend studies to heavy ion beam losses in drift-tube linac and superconducting linac accelerating structures. The studies indicate that the 1 W/m limit imposed on uncontrolled beam losses for high-energy proton beams might be relaxed for heavy ion beams. These studies further suggest that using the ratio of neutrons produced by a heavy ion beam to neutrons produced by a proton beam along with the dose rate from the proton beam (for thin-target scenarios) should allow an estimate of the dose rates expected from heavy ion beam losses.

  19. Background gas density and beam losses in NIO1 beam source

    Energy Technology Data Exchange (ETDEWEB)

    Sartori, E., E-mail: emanuele.sartori@igi.cnr.it; Veltri, P.; Serianni, G. [Consorzio RFX (CNR, ENEA, INFN, Università di Padova, Acciaierie Venete SpA), C.so Stati Uniti 4, 35127 Padova (Italy); Cavenago, M. [INFN-LNL, v.le dell’Università 2, I-35020 Legnaro (PD) (Italy)

    2016-02-15

    NIO1 (Negative Ion Optimization 1) is a versatile ion source designed to study the physics of production and acceleration of H- beams up to 60 keV. In ion sources, the gas is steadily injected in the plasma source to sustain the discharge, while high vacuum is maintained by a dedicated pumping system located in the vessel. In this paper, the three dimensional gas flow in NIO1 is studied in the molecular flow regime by the Avocado code. The analysis of the gas density profile along the accelerator considers the influence of effective gas temperature in the source, of the gas temperature accommodation by collisions at walls, and of the gas particle mass. The calculated source and vessel pressures are compared with experimental measurements in NIO1 during steady gas injection.

  20. Local energy losses at positive and negative steps in subcritical ...

    African Journals Online (AJOL)

    2010-04-22

    Apr 22, 2010 ... channel flow due to changes in channel width have been studied, to date no studies have been reported for losses due to changes in bed elevations. .... of these studies report on numerical modelling of flow over transitions. ... that the frictional losses are negligible, the energy equation between Sections (1) ...

  1. Evaluation of Beam Loss and Energy Depositions for a Possible Phase II Design for LHC Collimation

    International Nuclear Information System (INIS)

    Lari, L.; Assmann, R.; Bracco, C.; Brugger, M.; Cerutti, F.; Doyle, E.; Ferrari, A.; Keller, L.; Lundgren, S.; Markiewicz, Thomas W.; Mauri, M.; Redaelli, S.; Sarchiapone, L.; Smith, J.; Vlachoudis, V.; Weiler, T.

    2011-01-01

    The LHC beams are designed to have high stability and to be stored for many hours. The nominal beam intensity lifetime is expected to be of the order of 20h. The Phase II collimation system has to be able to handle particle losses in stable physics conditions at 7 TeV in order to avoid beam aborts and to allow correction of parameters and restoration to nominal conditions. Monte Carlo simulations are needed in order to evaluate the behavior of metallic high-Z collimators during operation scenarios using a realistic distribution of losses, which is a mix of the three limiting halo cases. Moreover, the consequences in the IR7 insertion of the worst (case) abnormal beam loss are evaluated. The case refers to a spontaneous trigger of the horizontal extraction kicker at top energy, when Phase II collimators are used. These studies are an important input for engineering design of the collimation Phase II system and for the evaluation of their effect on adjacent components. The goal is to build collimators that can survive the expected conditions during LHC stable physics runs, in order to avoid quenches of the SC magnets and to protect other LHC equipments.

  2. Evaluation of Beam Losses And Energy Deposition for a Possible Phase II Design for LHC Collimation

    International Nuclear Information System (INIS)

    Lari, L.; Bracco, C.; Assmann, R.W.; Brugger, M.; Cerutti, F.; Ferrari, A.; Mauri, M.; Redaelli, S.; Sarchiapone, L.; Vlachoudis, V.; Weiler, T.; Doyle, J.E.; Keller, L.; Lundgren, S.A.; Markiewicz, T.W.; Smith, J.C.

    2011-01-01

    The Large Hadron Collider (LHC) beams are designed to have high stability and to be stored for many hours. The nominal beam intensity lifetime is expected to be of the order of 20h. The Phase II collimation system has to be able to handle particle losses in stable physics conditions at 7 TeV in order to avoid beam aborts and to allow correction of parameters and restoration to nominal conditions. Monte Carlo simulations are needed in order to evaluate the behavior of metallic high-Z collimators during operation scenarios using a realistic distribution of losses, which is a mix of the three limiting halo cases. Moreover, the consequences in the IR7 insertion of the worst (case) abnormal beam loss are evaluated. The case refers to a spontaneous trigger of the horizontal extraction kicker at top energy, when Phase II collimators are used. These studies are an important input for engineering design of the collimation Phase II system and for the evaluation of their effect on adjacent components. The goal is to build collimators that can survive the expected conditions during LHC stable physics runs, in order to avoid quenches of the SC magnets and to protect other LHC equipments.

  3. Simulation of the ATLAS SCT barrel module response to LHC beam loss scenarios

    CERN Document Server

    Rose, P; The ATLAS collaboration; Fadeyev, V; Spencer, E; Wilder, M; Domingo, M

    2014-01-01

    In the event of beam loss at the LHC, ATLAS Inner Detector components nearest the beam line may be subjected to unusually large amounts of radiation. Understanding their behavior in such an event is important in determining whether they would still function properly. We built a SPICE model of the silicon strip module electrical system to determine the behavior of its elements during a realistic beam loss scenario. We found that the power supply and bias filter characteristics strongly affect the module response in such scenarios. In particular, the following self-limiting phenomena were observed: there is a finite amount of charge initially available on the bias filter capacitors for collection by the strips; the power supply current limit reduces the rate at which the bias filter capacitors' charge can be replenished; the reduced bias voltage leads to a smaller depletion depth in the sensors which results in less collected charge. These effects provide a larger measure of safety during beam loss events than ...

  4. Duration of memory loss due to electron beam exposure. Final report Jan-May 1983

    Energy Technology Data Exchange (ETDEWEB)

    Wheeler, T.G.; Tilton, B.M.

    1983-08-01

    Electron beam exposure has been shown to produce retrograde amnesia (RA). The objective of this study was to determine the duration of memory loss upon electron beam exposure. It is important to know if exposure produces a memory loss of the events which occurred in the preceding 1 sec or memory loss of the preceding minute's events. The task was a single-trial avoidance paradigm. The animal was placed in a small aversive chamber. After a 90-sec adaptation period, a door opened that provided access to a large, dark, preferred chamber. The time required for the animal to enter the preferred chamber was the measure of interest (T). Once inside the preferred chamber, a 1-sec footshock was delivered. Following the footshock by some preset delay (delta T), the animal was exposed to a 10-microsec, 10-rad electron beam (or X-ray). A second trial on the task was run 2 hr postexposure. The second trial consisted of placing the animal in the aversive chamber and monitoring the time (T') required to enter the preferred chamber. If the electron beam exposure interfered with the animal's ability to recall the shock, T' would be greatly reduced as compared with the sham controls. The exposure delay times used were delta T = 1, 3, 5, and 10 sec.

  5. Beam loss in HIRFL-CSR due to collisions with residual gas in vacuum

    International Nuclear Information System (INIS)

    Tang Jingyu; Lei Wen; Wang Yifang

    1998-01-01

    The author discusses the collision of heavy ions with residual gas atoms in the vacuum and the cross-sections of the collision processes. The method calculating beam transmission efficiency in vacuum is presented taking HIRFL and CSR machine as examples. Based on rich experimental data, a series of empirical formulae of calculating the cross-section of charge changing process is given. The transmission efficiency curves of different sections in HIRFL and CSR are also calculated, and thus the reasonable requirements for HIRFL and CSR vacuum systems are given. The calculation method has been checked by the measurements of vacuum and beam loss in HIRFL

  6. Low-beam-loss design of a compact, high-current deuteron radio frequency quadrupole accelerator

    Directory of Open Access Journals (Sweden)

    C. Zhang

    2004-10-01

    Full Text Available A 201.5 MHz, 50 mA, 2.0 MeV deuteron radio frequency quadrupole accelerator is proposed as the neutron generator for the neutron experiment facility project at Peking University, China. Based on better understanding of beam losses, some new optimization procedures concerning both longitudinal and transverse dynamics are adopted. Accordingly, the beam transmission efficiency is improved from 91.2% to 98.3% and the electrode length is shortened from 2.91 to 2.71 m. The fundamental physical analyses are performed to look inside the new design recipe and explain why it works.

  7. Allotropic effects on the energy loss of swift H+ and He+ ion beams through thin foils

    International Nuclear Information System (INIS)

    Garcia-Molina, Rafael; Abril, Isabel; Denton, Cristian D.; Heredia-Avalos, Santiago

    2006-01-01

    We have developed a theoretical treatment and a simulation code to study the energy loss of swift H + and He + ion beams interacting with thin foils of different carbon allotropes. The former is based on the dielectric formalism, and the latter combines Monte Carlo with the numerical solution of the motion equation for each projectile to describe its trajectory and interactions through the target. The capabilities of both methods are assessed by the reasonably good agreement between their predictions and the experimental results, for a wide range of projectile energies and target characteristics. Firstly, we apply the theoretical procedure to calculate the stopping cross sections for H + and He + beams in foils of different allotropic forms of carbon (such as diamond, graphite, amorphous carbon, glassy carbon and C 60 -fullerite), as a function of the projectile energy. We take into account the electronic structure of the projectile, as well as the different charge states it can acquire, the energy loss associated to the electronic capture and loss processes, the polarization of the projectile, and a realistic description of the target. On the other hand, the simulation code is used to evaluate the energy distributions of swift H + and He + ion beams when traversing several foils of the above mentioned allotropic forms of carbon, in order to analyze the influence of the chemical and physical state of the target in the projectile energy loss. These allotropic effects are found to become more important around the maximum of the stopping cross-section

  8. Radiative interaction of a focused relativistic electron beam in energy-loss spectroscopy of nanoscopic platelets

    International Nuclear Information System (INIS)

    Itskovsky, M. A.; Maniv, T.; Cohen, H.

    2008-01-01

    A quantum-mechanical scattering theory for relativistic, highly focused electron beams in the vacuum near nanoscopic platelets is presented, revealing an excitation mechanism due to the electron wave scattering from the platelet edges. Radiative electromagnetic excitations within the light cone are shown to arise, allowed by the breakdown of momentum conservation along the beam axis in the inelastic-scattering process. Calculated for metallic (silver and gold) and insulating (SiO 2 and MgO) nanoplatelets, radiative features are revealed above the main surface-plasmon-polariton peak, and dramatic enhancements in the electron-energy-loss probability at gaps of the 'classical' spectra are found. The corresponding radiation should be detectable in the vacuum far-field zone, with e beams exploited as sensitive 'tip detectors' of electronically excited nanostructures

  9. Radiative interaction of a focused relativistic electron beam in energy-loss spectroscopy of nanoscopic platelets

    Science.gov (United States)

    Itskovsky, M. A.; Cohen, H.; Maniv, T.

    2008-07-01

    A quantum-mechanical scattering theory for relativistic, highly focused electron beams in the vacuum near nanoscopic platelets is presented, revealing an excitation mechanism due to the electron wave scattering from the platelet edges. Radiative electromagnetic excitations within the light cone are shown to arise, allowed by the breakdown of momentum conservation along the beam axis in the inelastic-scattering process. Calculated for metallic (silver and gold) and insulating ( SiO2 and MgO) nanoplatelets, radiative features are revealed above the main surface-plasmon-polariton peak, and dramatic enhancements in the electron-energy-loss probability at gaps of the “classical” spectra are found. The corresponding radiation should be detectable in the vacuum far-field zone, with e beams exploited as sensitive “tip detectors” of electronically excited nanostructures.

  10. Controlled Transverse Blow-up of Highenergy Proton Beams for Aperture Measurements and Loss Maps

    CERN Document Server

    Hӧfle, W; Redaelli, S; Schmidt, R; Valuch, D; Wollmann, D; Zerlauth, M

    2012-01-01

    A technique was developed to blow-up transversely in a controlled way high energy proton beams in the LHC. The technique is based on band limited white noise excitation that is injected into the transverse damper feedback loop. The injected signal can be gated to selectively blow-up individual trains of bunches. The speed of transverse blow-up can be precisely controlled. This opens the possibility to perform safely and efficiently aperture measurements and loss maps with high intensity bunch trains well above stored beam energies that are considered to be safe. In particular, lengthy procedures for measurements at top energy, otherwise requiring multiple fills of individual bunches, can be avoided. In this paper, the method is presented and results from beam measurements are discussed and compared with alternative blowup methods.

  11. FESA class for off-momentum lossmaps and decomposition of beam losses at LHC

    CERN Document Server

    Wyszynski, Michal Jakub; Pojer, Mirko; Salvachua Ferrando, Belen Maria; Valentino, Gianluca; CERN. Geneva. ATS Department

    2016-01-01

    The project consisted of two main parts. The first part was to build a FESA class which would serve as lossmap feedback controller for off-momentum lossmaps, capable of handling 100 Hz BLM data, contrary to existing controller. Thanks to the efficient management RF frequency, beam dumps during this procedure would be avoided and machine availability would improve by shortening the duration of machine validation after technical stops. The second part concerned identification of beam losses at the LHC. It was a continuation of author’s work done as Summer Student project. The aim was to identify issues with the existing losses decomposition matrix for flat top, apply necessary corrections and construct analogous matrix for injection.

  12. Accidental beam loss in superconducting accelerators: Simulations, consequences of accidents and protective measures

    International Nuclear Information System (INIS)

    Drozhdin, A.; Mokhov, N.; Parker, B.

    1994-02-01

    The consequences of an accidental beam loss in superconducting accelerators and colliders of the next generation range from the mundane to rather dramatic, i.e., from superconducting magnet quench, to overheating of critical components, to a total destruction of some units via explosion. Specific measures are required to minimize and eliminate such events as much as practical. In this paper we study such accidents taking the Superconducting Supercollider complex as an example. Particle tracking, beam loss and energy deposition calculations were done using the realistic machine simulation with the Monte-Carlo codes MARS 12 and STRUCT. Protective measures for minimizing the damaging effects of prefire and misfire of injection and extraction kicker magnets are proposed here

  13. Precessed electron beam electron energy loss spectroscopy of graphene: Beyond channelling effects

    Energy Technology Data Exchange (ETDEWEB)

    Yedra, Ll.; Estradé, S., E-mail: sestrade@ub.edu [LENS, MIND-IN2UB, Departament d' Electrònica, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona (Spain); TEM-MAT, CCiT, Universitat de Barcelona, Solé i Sabarís 1, 08028 Barcelona (Spain); Torruella, P.; Eljarrat, A.; Peiró, F. [LENS, MIND-IN2UB, Departament d' Electrònica, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona (Spain); Darbal, A. D. [AppFive LLC, 1095 W Rio Salado Pkway, Suite 110, Tempe, Arizona 85281 (United States); Weiss, J. K. [AppFive LLC, 1095 W Rio Salado Pkway, Suite 110, Tempe, Arizona 85281 (United States); NanoMEGAS SPRL, Blvd. Edmond Machtens 79, B-1080 Brussels (Belgium)

    2014-08-04

    The effects of beam precession on the Electron Energy Loss Spectroscopy (EELS) signal of the carbon K edge in a 2 monolayer graphene sheet are studied. In a previous work, we demonstrated the use of precession to compensate for the channeling-induced reduction of EELS signal when in zone axis. In the case of graphene, no enhancement of EELS signal is found in the usual experimental conditions, as graphene is not thick enough to present channeling effects. Interestingly, though it is found that precession makes it possible to increase the collection angle, and, thus, the overall signal, without a loss of signal-to-background ratio.

  14. Reliability of the Beam Loss Monitors System for the Large Hadron Collider at CERN

    CERN Document Server

    Guaglio, G; Santoni, C

    2005-01-01

    The energy stored in the Large Hadron Collider is unprecedented. The impact of the beam particles can cause severe damage on the superconductive magnets, resulting in significant downtime for repairing. The Beam Loss Monitors System (BLMS) detects the secondary particles shower of the lost beam particles and initiates the extraction of the beam before any serious damage to the equipment can occur. This thesis defines the BLMS specifications in term of reliability. The main goal is the design of a system minimizing both the probability to not detect a dangerous loss and the number of false alarms generated. The reliability theory and techniques utilized are described. The prediction of the hazard rates, the testing procedures, the Failure Modes Effects and Criticalities Analysis and the Fault Tree Analysis have been used to provide an estimation of the probability to damage a magnet, of the number of false alarms and of the number of generated warnings. The weakest components in the BLMS have been pointed out....

  15. Interaction between corrosion crack width and steel loss in RC beams corroded under load

    International Nuclear Information System (INIS)

    Malumbela, Goitseone; Alexander, Mark; Moyo, Pilate

    2010-01-01

    This paper presents results and discussions on an experimental study conducted to relate the rate of widening of corrosion cracks with the pattern of corrosion cracks as well as the level of steel corrosion for RC beams (153 x 254 x 3000 mm) that were corroded whilst subjected to varying levels of sustained loads. Steel corrosion was limited to the tensile reinforcement and to a length of 700 mm at the centre of the beams. The rate of widening of corrosion cracks as well as strains on uncracked faces of RC beams was constantly monitored during the corrosion process, along the corrosion region and along other potential cracking faces of beams using a demec gauge. The distribution of the gravimetric mass loss of steel along the corrosion region was measured at the end of the corrosion process. The results obtained showed that: the rate of widening of each corrosion crack is dependent on the overall pattern of the cracks whilst the rate of corrosion is independent of the pattern of corrosion cracks. A mass loss of steel of 1% was found to induce a corrosion crack width of about 0.04 mm.

  16. Beam shape coefficients calculation for an elliptical Gaussian beam with 1-dimensional quadrature and localized approximation methods

    Science.gov (United States)

    Wang, Wei; Shen, Jianqi

    2018-06-01

    The use of a shaped beam for applications relying on light scattering depends much on the ability to evaluate the beam shape coefficients (BSC) effectively. Numerical techniques for evaluating the BSCs of a shaped beam, such as the quadrature, the localized approximation (LA), the integral localized approximation (ILA) methods, have been developed within the framework of generalized Lorenz-Mie theory (GLMT). The quadrature methods usually employ the 2-/3-dimensional integrations. In this work, the expressions of the BSCs for an elliptical Gaussian beam (EGB) are simplified into the 1-dimensional integral so as to speed up the numerical computation. Numerical results of BSCs are used to reconstruct the beam field and the fidelity of the reconstructed field to the given beam field is estimated. It is demonstrated that the proposed method is much faster than the 2-dimensional integrations and it can acquire more accurate results than the LA method. Limitations of the quadrature method and also the LA method in the numerical calculation are analyzed in detail.

  17. Simulation of the ATLAS SCT Barrel Module Response to LHC Beam Loss Scenarios

    CERN Document Server

    Rose, P; The ATLAS collaboration; Fadeyev, V; Spencer, E; Wilder, M; Domingo, M

    2013-01-01

    In the event of beam loss at the LHC, ATLAS Inner Detector components nearest the beamline may be subjected to unusually large amounts of radiation. Understanding their behavior in such an event is important in determining whether they would still function properly. We built a SPICE model of the silicon strip module electrical system to determine the behavior of its elements during a realistic beam loss scenario. We found that the power supply and bias filter characteristics strongly affect the module response in such scenarios. In particular, the following self-limiting phenomena were observed: there is a finite amount of charge initially available on the bias filter capacitors for collection by the strips; the power supply current limit reduces the rate at which the bias filter capacitors' charge can be replenished; the reduced bias voltage leads to a smaller depletion depth which results in less collected charge. These effects provide a larger measure of safety during beam loss events than we have previous...

  18. A state variable approach to the BESSY II local beam-position-feedback system

    International Nuclear Information System (INIS)

    Gilpatrick, J.D.; Khan, S.; Kraemer, D.

    1996-01-01

    At the BESSY II facility, stability of the electron beam position and angle near insertion devices (IDs) is of utmost importance. Disturbances due to ground motion could result in unwanted broad-bandwidth beam-jitter which decreases the electron (and resultant photon) beam's effective brightness. Therefore, feedback techniques must be used. Operating over a frequency range of 100-Hz, a local feedback system will correct these beam-trajectory errors using the four bumps around IDs. This paper reviews how the state-variable feedback approach can be applied to real-time correction of these beam position and angle errors. A frequency-domain solution showing beam jitter reduction is presented. Finally, this paper reports results of a beam-feedback test at BESSY I

  19. Special features of local spatial spectrum of Bessel light beams

    CSIR Research Space (South Africa)

    Belyi, VN

    2011-11-01

    Full Text Available In this paper the authors consider the angular spectrum of an apertured Bessel beam when the aperture is circular and shifted laterally with respect to the optical axis. Since the perturbation of the resulting angular spectrum is due to a spatially...

  20. Improved Beam Angle Arrangement in Intensity Modulated Proton Therapy Treatment Planning for Localized Prostate Cancer

    International Nuclear Information System (INIS)

    Cao, Wenhua; Lim, Gino J.; Li, Yupeng; Zhu, X. Ronald; Zhang, Xiaodong

    2015-01-01

    Purpose: This study investigates potential gains of an improved beam angle arrangement compared to a conventional fixed gantry setup in intensity modulated proton therapy (IMPT) treatment for localized prostate cancer patients based on a proof of principle study. Materials and Methods: Three patients with localized prostate cancer retrospectively selected from our institution were studied. For each patient, IMPT plans were designed using two, three and four beam angles, respectively, obtained from a beam angle optimization algorithm. Those plans were then compared with ones using two lateral parallel-opposed beams according to the conventional planning protocol for localized prostate cancer adopted at our institution. Results: IMPT plans with two optimized angles achieved significant improvements in rectum sparing and moderate improvements in bladder sparing against those with two lateral angles. Plans with three optimized angles further improved rectum sparing significantly over those two-angle plans, whereas four-angle plans found no advantage over three-angle plans. A possible three-beam class solution for localized prostate patients was suggested and demonstrated with preserved dosimetric benefits because individually optimized three-angle solutions were found sharing a very similar pattern. Conclusions: This study has demonstrated the potential of using an improved beam angle arrangement to better exploit the theoretical dosimetric benefits of proton therapy and provided insights of selecting quality beam angles for localized prostate cancer treatment

  1. Reliability of the beam loss monitors system for the large hadron collider at CERN

    International Nuclear Information System (INIS)

    Guaglio, G.

    2005-12-01

    The energy stored in the Large Hadron Collider is unprecedented. The impact of the beam particles can cause severe damage on the superconductive magnets, resulting in significant downtime for repairing. The Beam Loss Monitors System (BLMS) detects the secondary particles shower of the lost beam particles and initiates the extraction of the beam before any serious damage to the equipment can occur. This thesis defines the BLMS specifications in term of reliability. The main goal is the design of a system minimizing both the probability to not detect a dangerous loss and the number of false alarms generated. The reliability theory and techniques utilized are described. The prediction of the hazard rates, the testing procedures, the Failure Modes Effects and Criticalities Analysis and the Fault Tree Analysis have been used to provide an estimation of the probability to damage a magnet, of the number of false alarms and of the number of generated warnings. The weakest components in the BLMS have been pointed out. The reliability figures of the BLMS have been calculated using a commercial software package (Isograph.). The effect of the variation of the parameters on the obtained results has been evaluated with a sensitivity analysis. The reliability model has been extended by the results of radiation tests. Design improvements, like redundant optical transmission, have been implemented in an iterative process. The proposed system is compliant with the reliability requirements. The model uncertainties are given by the limited knowledge of the thresholds levels of the superconductive magnets and of the locations of the losses along the ring. The implemented model allows modifications of the system, following the measuring of the hazard rates during the LHC life. It can also provide reference numbers to other accelerators which will implement similar technologies. (author)

  2. Quench Tests of LHC Magnets with Beam: Studies on Beam Loss development and determination of Quench levels

    CERN Document Server

    Priebe, A; Sapinski, M

    The application of superconducting materials in the field of high energy accelerator physics not only opens the doors to the generation of the magnetic fields unattainable to normal conductors but also demands facing new challenges. A transition fromthe superconducting state, which is characterized by a resistance-free flow of the electric current, to the normal conducting state is called quenching. This process might be extremely dangerous and even lead to destruction of amagnet superconducting coil if no protecting actions are taken. Therefore, the knowledge of a magnet quench level, i.e. amount of energy which causes the transition to the resistive state, is crucial for the safety and operational efficiency of the accelerator. Regarding that, specific thresholds are incorporated to dedicated quench prevention systems in order to suppress the origin of detected energy perturbation, for example beam losses, or mitigate the consequences of the quenching process by dissipating the energy stored in the magnetic...

  3. Simulation of multicomponent losses in electron beam melting and refining at varying scan frequencies

    International Nuclear Information System (INIS)

    Powell, A.; Szekely, J.; Van Den Avyle, J.; Damkroger, B.

    1995-01-01

    A two-stage model is presented to describe alloy element evaporation rates from molten metal due to transient local heating by an electron beam. The first stage is a simulation of transient phenomena near the melt surface due to periodic heating by a scanning beam, the output of which is the relationship between operating parameters, surface temperature, and evaporation rate. At high scan rates, this can be done using a simple one-dimensional heat transfer model of the surface layer; at lower scan rates, a more complex three-dimensional model with fluid flow and periodic boundary conditions is necessary. The second stage couples this evaporation-surface temperature relationship with a larger steady state heat transfer and fluid flow model of an entire melting hearth or mold, in order to calculate local and total evaporation rates. Predictions are compared with experimental results from Sandia's 310-kW electron beam melting furnace, in which evaporation rates and vapor compositions were studied in pure titanium and Ti-6%Al-4%V alloy. Evaporation rates were estimated from rate of condensation on a substrate held over the hearth, and were characterized as a function of beam power (150 and 225 kW), scan frequency (30, 115 and 450 Hz) and background pressure (10 -3 , 10 -4 and 10 -5 torr)

  4. Prestress Loss and Bending Capacity of Pre-cracked 40 Year-Old PC Beams Exposed to Marine Environment

    Directory of Open Access Journals (Sweden)

    Dasar Amry

    2016-01-01

    Full Text Available Six prestressed concrete beams (PC beam were used for evaluation, consist of four post-tension beams (PC-O and two pre-tension beams (PC-R. In order to investigate the effect of crack on prestress loss and bending capacity after long-term exposed, prestressed concrete beams were pre-crack and then exposed to marine environment. Experimental work was carried out to evaluate PC beams performance after long-term exposed. In addition, visual observations and load bearing capacity test was carried out. Furthermore, evaluation of prestress loss conducted using three-point loading bending test and the remaining tendon forces in the beam were determined using Crack Re-opening Method. The experimental results revealed that prestress loss was increased due to corrosion of strand/wire which affected by the pre-crack on the prestressed beams. Approximately a prestress loss around 26% and 30% was recorded for post-tension and pre-tension beams respectively.

  5. Severe signal loss in diamond beam loss monitors in high particle rate environments by charge trapping in radiation-induced defects

    Energy Technology Data Exchange (ETDEWEB)

    Kassel, Florian; Boer, Wim de [Institute for Experimental Nuclear Physics (IEKP), KIT, Karlsruhe (Germany); Guthoff, Moritz; Dabrowski, Anne [CERN, Meyrin (Switzerland)

    2016-10-15

    The beam condition monitoring leakage (BCML) system is a beam monitoring device in the compact muon solenoid (CMS) experiment at the large hadron collider (LHC). As detectors 32 poly-crystalline (pCVD) diamond sensors are positioned in rings around the beam pipe. Here, high particle rates occur from the colliding beams scattering particles outside the beam pipe. These particles cause defects, which act as traps for the ionization, thus reducing the charge collection efficiency (CCE). However, the loss in CCE was much more severe than expected from low rate laboratory measurements and simulations, especially in single-crystalline (sCVD) diamonds, which have a low initial concentration of defects. After an integrated luminosity of a few fb{sup -1} corresponding to a few weeks of LHC operation, the CCE of the sCVD diamonds dropped by a factor of five or more and quickly approached the poor CCE of pCVD diamonds. The reason why in real experiments the CCE is much worse than in laboratory experiments is related to the ionization rate. At high particle rates the trapping rate of the ionization is so high compared with the detrapping rate, that space charge builds up. This space charge reduces locally the internal electric field, which in turn increases the trapping rate and recombination and hence reduces the CCE in a strongly non-linear way. A diamond irradiation campaign was started to investigate the rate-dependent electrical field deformation with respect to the radiation damage. Besides the electrical field measurements via the transient current technique (TCT), the CCE was measured. The experimental results were used to create an effective deep trap model that takes the radiation damage into account. Using this trap model, the rate-dependent electrical field deformation and the CCE were simulated with the software SILVACO TCAD. The simulation, tuned to rate-dependent measurements from a strong radioactive source, was able to predict the non-linear decrease of the

  6. Severe signal loss in diamond beam loss monitors in high particle rate environments by charge trapping in radiation-induced defects

    International Nuclear Information System (INIS)

    Kassel, Florian; Boer, Wim de; Guthoff, Moritz; Dabrowski, Anne

    2016-01-01

    The beam condition monitoring leakage (BCML) system is a beam monitoring device in the compact muon solenoid (CMS) experiment at the large hadron collider (LHC). As detectors 32 poly-crystalline (pCVD) diamond sensors are positioned in rings around the beam pipe. Here, high particle rates occur from the colliding beams scattering particles outside the beam pipe. These particles cause defects, which act as traps for the ionization, thus reducing the charge collection efficiency (CCE). However, the loss in CCE was much more severe than expected from low rate laboratory measurements and simulations, especially in single-crystalline (sCVD) diamonds, which have a low initial concentration of defects. After an integrated luminosity of a few fb -1 corresponding to a few weeks of LHC operation, the CCE of the sCVD diamonds dropped by a factor of five or more and quickly approached the poor CCE of pCVD diamonds. The reason why in real experiments the CCE is much worse than in laboratory experiments is related to the ionization rate. At high particle rates the trapping rate of the ionization is so high compared with the detrapping rate, that space charge builds up. This space charge reduces locally the internal electric field, which in turn increases the trapping rate and recombination and hence reduces the CCE in a strongly non-linear way. A diamond irradiation campaign was started to investigate the rate-dependent electrical field deformation with respect to the radiation damage. Besides the electrical field measurements via the transient current technique (TCT), the CCE was measured. The experimental results were used to create an effective deep trap model that takes the radiation damage into account. Using this trap model, the rate-dependent electrical field deformation and the CCE were simulated with the software SILVACO TCAD. The simulation, tuned to rate-dependent measurements from a strong radioactive source, was able to predict the non-linear decrease of the CCE in

  7. Perturbation of the energy loss spectra for an accelerated electron beam due to the photo injector exit

    CERN Document Server

    Salah, W

    2003-01-01

    The influence of the photo-injector exit hall on the energy loss for an accelerated electron beam is investigated, by calculating the total energy transferred from the electrons to the wakefields, which are driven by the beam. The obtained energy loss is compared to those previously obtained for a 'pill-box' cavity. This comparison shows that the influence of this hall, in terms of energy loss, varies over the beam length. It is strongest in the middle of the beam and decreases towards both ends. In consequence of this perturbation, the center of the beam is displaced from its initial position during the first phase (t < 200 ps) where the exit aperture has no effect to a new equilibrium position which takes place at 200 < t < 250 ps. (author)

  8. Design guidelines for flexural wave attenuation of slender beams with local resonators

    International Nuclear Information System (INIS)

    Liu, Yaozong; Yu, Dianlong; Li, Li; Zhao, Honggang; Wen, Jihong; Wen, Xisen

    2007-01-01

    The complex band structures and attenuation spectra of flexural waves in slender beams with periodically mounted local resonators are investigated with transfer matrix method. It is noteworthy that the frequency range and attenuation coefficient of the locally resonant gap become larger in complex band structures if larger resonators were used. But given the total add-on mass of resonators, the attenuation spectra of finite beams with large but few resonators do not demonstrate such phenomena because the attenuation needs several periods to establish. So with the view of application, a large number of small local resonators widely spread along the beam are preferred given the total add-on mass to the beam

  9. Investigation of local spatial spectra of Bessel light beams

    CSIR Research Space (South Africa)

    Belyi, VN

    2009-08-01

    Full Text Available plane of lens and illuminated by plane wave. The superposition of plane waves in such scheme is proposed to be generated by point sources distributed within the circular diaphragm. In a case when diaphragm is placed outside of lens focus [2], Bessel... beam can be described as an image in lens of spherical waves superposition formed by some effective circular source in object plane of lens. In the scheme of BLB obtaining based on axicons, the appearance of superposition of plane waves can be studied...

  10. Synthesis of Pt nanoparticles and their burrowing into Si due to synergistic effects of ion beam energy losses

    Directory of Open Access Journals (Sweden)

    Pravin Kumar

    2014-10-01

    Full Text Available We report the synthesis of Pt nanoparticles and their burrowing into silicon upon irradiation of a Pt–Si thin film with medium-energy neon ions at constant fluence (1.0 × 1017 ions/cm2. Several values of medium-energy neon ions were chosen in order to vary the ratio of the electronic energy loss to the nuclear energy loss (Se/Sn from 1 to 10. The irradiated films were characterized using Rutherford backscattering spectroscopy (RBS, atomic force microscopy (AFM, scanning electron microscopy (SEM, X-ray diffraction (XRD and high resolution transmission electron microscopy (HRTEM. A TEM image of a cross section of the film irradiated with Se/Sn = 1 shows ≈5 nm Pt NPs were buried up to ≈240 nm into the silicon. No silicide phase was detected in the XRD pattern of the film irradiated at the highest value of Se/Sn. The synergistic effect of the energy losses of the ion beam (molten zones are produced by Se, and sputtering and local defects are produced by Sn leading to the synthesis and burrowing of Pt NPs is evidenced. The Pt NP synthesis mechanism and their burrowing into the silicon is discussed in detail.

  11. Loss of beam ions to the inside of the PDX [Poloidal Divertor Experiment] tokamak during the fishbone instability

    International Nuclear Information System (INIS)

    Heidbrink, W.W.; Beiersdorfer, P.

    1986-11-01

    Using data from two vertical charge-exchange detectors on the Poloidal Divertor Experiment (PDX), we have identified a set of conditions for which loss of beam ions inward in major radius is observed during the fishbone instability. Previously, it was reported that beam ions were lost only to the outside of the PDX tokamak

  12. Evaluation of support loss in micro-beam resonators: A revisit

    Science.gov (United States)

    Chen, S. Y.; Liu, J. Z.; Guo, F. L.

    2017-12-01

    This paper presents an analytical study on evaluation of support loss in micromechanical resonators undergoing in-plane flexural vibrations. Two-dimensional elastic wave theory is used to determine the energy transmission from the vibrating resonator to the support. Fourier transform and Green's function technique are adopted to solve the problem of wave motions on the surface of the support excited by the forces transmitted by the resonator onto the support. Analytical expressions of support loss in terms of quality factor, taking into account distributed normal stress and shear stress in the attachment region, and coupling between the normal stress and shear stress as well as material disparity between the support and the resonator, have been derived. Effects of geometry of micro-beam resonators, and material dissimilarity between support and resonator on support loss are examined. Numerical results show that 'harder resonator' and 'softer support' combination leads to larger support loss. In addition, the Perfectly Matched Layer (PML) numerical simulation technique is employed for validation of the proposed analytical model. Comparing with results of quality factor obtained by PML technique, we find that the present model agrees well with the results of PML technique and the pure-shear model overestimates support loss noticeably, especially for resonators with small aspect ratio and large material dissimilarity between the support and resonator.

  13. Early experience of proton beam therapy combined with chemotherapy for locally advanced oropharyngeal cancer

    International Nuclear Information System (INIS)

    Ishikawa, Youjirou; Nakamura, Tatsuya; Takada, Akinori; Takayama, Kanako; Makita, Chiyoko; Suzuki, Motohisa; Azami, Yusuke; Kikuchi, Yasuhiro; Fuwa, Nobukazu

    2013-01-01

    Between 2009 and 2012, 10 patients with advanced oropharyngeal cancer underwent proton therapy combined with chemotherapy. The initial results of this therapy were 8 complete response (CR) and 2 partial response (PR), local recurrence was detected 1 patient. Proton beam therapy combined with chemotherapy is thought to be an effective treatment for locally advanced oropharyngeal cancer. (author)

  14. Individually controlled localized chilled beam in conjunction with chilled ceiling: Part 2 – Human response

    DEFF Research Database (Denmark)

    Arghand, Taha; Pastuszka, Zuzanna; Bolashikov, Zhecho Dimitrov

    2016-01-01

    The response of 24 subjects to the local environment established by localized chilled beam combined with chilled ceiling (LCBCC) was studied and compared with response to the environment generated by mixing ventilation combined with chilled ceiling (CCMV) at two temperature conditions of 26°C and...

  15. Effect of laser beam filamentation on plasma wave localization and stimulated Raman scattering

    International Nuclear Information System (INIS)

    Purohit, Gunjan; Sharma, R. P.

    2013-01-01

    This paper presents the effect of laser beam filamentation on the localization of electron plasma wave (EPW) and stimulated Raman scattering (SRS) in unmagnitized plasma when both relativistic and ponderomotive nonlinearities are operative. The filamentary dynamics of laser beam is studied and the splitted profile of the laser beam is obtained due to uneven focusing of the off-axial rays. The localization of electron plasma wave takes place due to nonlinear coupling between the laser beam and EPW. Stimulated Raman scattering of this EPW is studied and backreflectivity has been calculated. The localization of EPW also affects the eigenfrequency and damping of plasma wave; consequently, mismatch and modified enhanced Landau damping lead to the disruption of SRS process and a substantial reduction in the backreflectivity. The new enhanced damping of the plasma wave has been calculated and it is found that the SRS process gets suppressed due to the localization of plasma wave in laser beam filamentary structures. For typical laser beam and plasma parameters with wavelength λ (=1064 nm), power flux (=10 16 W/cm 2 ) and plasma density (n/n cr ) = 0.2; the SRS back reflectivity is found to be suppressed by a factor of around 5%. (author)

  16. Prompt Loss of Energetic Ions during Early Neutral Beam Injection in the National Spherical Torus Experiment

    International Nuclear Information System (INIS)

    Medley, S.S.; Darrow, D.S.; Liu, D.; Roquemore, A.L.

    2005-01-01

    Early neutral-beam injection is used in the National Spherical Torus Experiment (NSTX) to heat the electrons and slow current penetration which keeps q(0) elevated to avoid deleterious MHD activity and at the same time reduces Ohmic flux consumption, all of which aids long-pulse operation. However, the low plasma current (I p ∼ 0.5 MA) and electron density (n e ∼ 1 x 10 13 cm -3 ) attending early injection lead to elevated orbit and shine through losses. The inherent orbit losses are aggravated by large excursions in the outer gap width during current ramp-up. An investigation of this behavior using various energetic particle diagnostics on NSTX and TRANSP code analysis is presented

  17. Real-Time System Supervision for the LHC Beam Loss Monitoring System at CERN

    CERN Document Server

    Zamantzas, C; Effinger, E; Emery, J; Jackson, S

    2014-01-01

    The strategy for machine protection and quench prevention of the Large Hadron Collider (LHC) at the European Organisation for Nuclear Research (CERN) is mainly based on the Beam Loss Monitoring (BLM) system. The LHC BLM system is one of the most complex and large instrumentation systems deployed in the LHC. In addition to protecting the collider, the system also needs to provide a means of diagnosing machine faults and deliver feedback of the losses to the control room as well as to several systems for their setup and analysis. In order to augment the dependability of the system several layers of supervision has been implemented internally and externally to the system. This paper describes the different methods employed to achieve the expected availability and system fault detection.

  18. A model for particle and heat losses by type I edge localized modes

    International Nuclear Information System (INIS)

    Tokar, M Z; Gupta, A; Kalupin, D; Singh, R

    2007-01-01

    A model to estimate the particle and energy losses caused in tokamaks by type I edge localized modes (ELMs) is proposed. This model is based on the assumption that the increase in transport by ELM is due to flows along magnetic field lines perturbed by ballooning-peeling MHD modes. The model reproduces well the experimentally found variation of losses with the plasma collisionality ν*, namely, the weak dependence of the particle loss and significant reduction of the energy loss with increasing ν*. It is argued that the electron parallel heat conductivity is dominating in the energy loss at not very large ν*

  19. The small length scale effect for a non-local cantilever beam: a paradox solved.

    Science.gov (United States)

    Challamel, N; Wang, C M

    2008-08-27

    Non-local continuum mechanics allows one to account for the small length scale effect that becomes significant when dealing with microstructures or nanostructures. This paper presents some simplified non-local elastic beam models, for the bending analyses of small scale rods. Integral-type or gradient non-local models abandon the classical assumption of locality, and admit that stress depends not only on the strain value at that point but also on the strain values of all points on the body. There is a paradox still unresolved at this stage: some bending solutions of integral-based non-local elastic beams have been found to be identical to the classical (local) solution, i.e. the small scale effect is not present at all. One example is the Euler-Bernoulli cantilever nanobeam model with a point load which has application in microelectromechanical systems and nanoelectromechanical systems as an actuator. In this paper, it will be shown that this paradox may be overcome with a gradient elastic model as well as an integral non-local elastic model that is based on combining the local and the non-local curvatures in the constitutive elastic relation. The latter model comprises the classical gradient model and Eringen's integral model, and its application produces small length scale terms in the non-local elastic cantilever beam solution.

  20. A hand-held sensor for analyses of local distributions of magnetic fields and losses

    CERN Document Server

    Krismanic, G; Baumgartinger, N

    2000-01-01

    The paper describes a novel sensor for non-destructive analyses of local field and loss distributions in laminated soft magnetic cores, such as transformer cores. It was designed for rapid information on comparative local degrees of inhomogeneity, e.g., for the estimation of local building factors. Similar to a magnifying glass with handle, the compact hand-held sensor contains extremely sharp needle electrodes for the detection of the induction vector B as well as double-field coils for the vector H. Losses P are derived from the Poynting law. Applied to inner -- or also outer -- core regions, the sensor yields instantaneous computer displays of local H, B, and P.

  1. Local loss and spatial homogenization of plant diversity reduce ecosystem multifunctionality

    Science.gov (United States)

    Experimental studies show that local plant species loss decreases ecosystem functioning and services, but it remains unclear how other changes in biodiversity, such as spatial homogenization, alter multiple processes (multifunctionality) in natural ecosystems. We present a global analysis of eight ...

  2. Luminosity, Beamstrahlung energy loss and beam-beam deflections for e+e- and e-e- collisions at the ILC with 500 GeV and varying transverse beam sizes

    International Nuclear Information System (INIS)

    Alabau Pons, M.; Bambade, P.; Faus-Golfe, A.

    2006-01-01

    At the interaction point of the International Linear Collider, beam-beam effects due to the strong electromagnetic fields that the bunches experience during collisions cause a mutual focusing, called pinch effect, which enhances the luminosity in the case of e + e - collisions. The opposite is true for e - e - collisions. In this case the luminosity is reduced by mutual defocusing, or anti-pinching. The resulting Beamstrahlung energy loss and beam-beam deflection angles as function of the vertical transverse offset are also different for both modes of operation. The dependence of these quantities with transverse beam sizes are presented for the case of e - e - collisions

  3. On scaling and optimization of high-intensity, low-beam-loss RF linacs for neutron source drivers

    International Nuclear Information System (INIS)

    Jameson, R.A.

    1992-01-01

    RF linacs providing cw proton beams of 30--250 mA at 800--1600 MeV, and cw deuteron beams of 100--250 mA at 35--40 MeV, are needed as drivers for factory neutron sources applied to radioactive waste transmutation, advanced energy production, materials testing facilities, and spallation neutron sources. The maintenance goals require very low beam loss along the linac. Optimization of such systems is complex; status of beam dynamics aspects presently being investigated is outlined

  4. Deriving motion from megavoltage localization cone beam computed tomography scans

    International Nuclear Information System (INIS)

    Alfredo C Siochi, R

    2009-01-01

    Cone beam computed tomography (CBCT) projection data consist of views of a moving point (e.g. diaphragm apex). The point is selected in identification views of extreme motion (two inhale, two exhale). The room coordinates of the extreme points are determined by source-to-view ray tracing intersections. Projected to other views, these points become opposite corners of a motion-bounding box. The view coordinates of the point, relative to the box, are used to interpolate between extreme room coordinates. Along with the views' time stamps, this provides the point's room coordinates as a function of time. CBCT-derived trajectories of a tungsten pin, moving 3 cm cranio-caudally and 1 cm elsewhere, deviate from expected ones by at most 1.06 mm. When deviations from the ideal imaging geometry are considered, mean errors are less than 0.2 mm. While CBCT-derived cranio-caudal positions are insensitive to the choice of identification views, the bounding box determination requires view separations between 15 and 163 deg. Inhale views with the two largest amplitudes should be used, though corrections can account for different amplitudes. The information could be used to calibrate motion surrogates, adaptively define phase triggers immediately before gated radiotherapy and provide phase and amplitude sorting for 4D CBCT.

  5. Preliminary design of the beam loss monitor system for the Advanced Photon Source

    International Nuclear Information System (INIS)

    Patterson, D.R.

    1992-01-01

    The preliminary design of the beam loss monitor for the ANL Advanced Photon Source is based on the use of an air dielectric coaxial cable as a long ionization chamber. Each coaxial cable section uses a high sensitivity DC current-to-voltage converter with both linear and integrating ranges. Pulse timing circuits determine the positions of individual losses by measuring the time at which the resulting voltage pulses arrive at the beginning of the coaxial ionization chamber. A possible timing ambiguity can be removed by correlating the particle bunch timing with the resulting voltage pulse timing. Measurements have shown that pulse rise times less than 15 nanoseconds can be obtained, so that determining loss locations to better than 7 feet may be possible. Best performance may be obtained when 500 VDC is applied to a 50-ohm, 7/8-inch air dielectric coaxial cable filled with approximately 8 psig of a 95% argon, 5% carbon dioxide gas mixture. Cable lengths will be between 100 and 300 feet long, depending on the part of the accelerator being monitored

  6. Retrograde amnesia produced by electron beam exposure: causal parameters and duration of memory loss

    International Nuclear Information System (INIS)

    Wheeler, T.G.; Hardy, K.A.

    1985-01-01

    The production of retrograde amnesia (RA) upon electron beam exposure has been investigated. RA production was evaluated using a single-trial avoidance task across a 10 4 dose range for 10-, 1-, and 0.1-μsec pulsed exposures. The dose-response curve obtained at each pulse duration showed significant RA production. The most effective dose range was 0.1-10 rad at a dose rate of 10 6 rad/sec. By employing a 10 rad (10 6 rad/sec) pulse, a memory loss of the events occurring in the previous 4 sec was demonstrated. The conclusion was that the RA effect might be due to sensory activation which provided a novel stimulus that masked previous stimuli

  7. Retrograde amnesia produced by electron beam exposure: causal parameters and duration of memory loss. [Rats

    Energy Technology Data Exchange (ETDEWEB)

    Wheeler, T.G.; Hardy, K.A.

    1985-01-01

    The production of retrograde amnesia (RA) upon electron beam exposure has been investigated. RA production was evaluated using a single-trial avoidance task across a 10/sup 4/ dose range for 10-, 1-, and 0.1-..mu..sec pulsed exposures. The dose-response curve obtained at each pulse duration showed significant RA production. The most effective dose range was 0.1-10 rad at a dose rate of 10/sup 6/ rad/sec. By employing a 10 rad (10/sup 6/ rad/sec) pulse, a memory loss of the events occurring in the previous 4 sec was demonstrated. The conclusion was that the RA effect might be due to sensory activation which provided a novel stimulus that masked previous stimuli.

  8. Capture from pair production as a beam loss mechanism for heavy ions at RHIC

    International Nuclear Information System (INIS)

    Feinberg, B.; Belkacem, A.; Claytor, N.; Dinneen, T.; Gould, H.

    1997-05-01

    Electron capture from electron-positron pair production is predicted to be a major source of beam loss for the heaviest ions at RHIC. Achieving the highest luminosity thus requires an understanding of the capture process. The authors report measurements of this process at Brookhaven National Laboratory's AGS using 10.8 GeV/nucleon Au 79+ projectiles on Au targets. Capture from pair production is a process in which the very high electromagnetic field involved in the collision of two relativistic heavy ions results in the production of an electron-positron pair with the capture of the electron by one of the ions. There are many theoretical papers published on capture from pair production with discrepancies between predicted cross sections. The experimental results are compared to theory and to previous experiments at 1 GeV/nucleon. The implications of extrapolations to RHIC energies are presented

  9. Development of silicon detectors for Beam Loss Monitoring at HL-LHC

    Science.gov (United States)

    Verbitskaya, E.; Eremin, V.; Zabrodskii, A.; Bogdanov, A.; Shepelev, A.; Dehning, B.; Bartosik, M. R.; Alexopoulos, A.; Glaser, M.; Ravotti, F.; Sapinski, M.; Härkönen, J.; Egorov, N.; Galkin, A.

    2017-03-01

    Silicon detectors were proposed as novel Beam Loss Monitors (BLM) for the control of the radiation environment in the vicinity of the superconductive magnets of the High-Luminosity Large Hadron Collider. The present work is aimed at enhancing the BLM sensitivity and therefore the capability of triggering the beam abort system before a critical radiation load hits the superconductive coils. We report here the results of three in situ irradiation tests of Si detectors carried out at the CERN PS at 1.9-4.2 K. The main experimental result is that all silicon detectors survived irradiation up to 1.22× 1016 p/cm2. The third test, focused on the detailed characterization of the detectors with standard (300 μm) and reduced (100 μm) thicknesses, showed only a marginal difference in the sensitivity of thinned detectors in the entire fluence range and a smaller rate of signal degradation that promotes their use as BLMs. The irradiation campaigns produced new information on radiation damage and carrier transport in Si detectors irradiated at the temperatures of 1.9-4.2 K. The results were encouraging and permitted to initiate the production of the first BLM prototype modules which were installed at the end of the vessel containing the superconductive coil of a LHC magnet immersed in superfluid helium to be able to test the silicon detectors in real operational conditions.

  10. Structural activation calculations due to proton beam loss in the APT accelerator design

    International Nuclear Information System (INIS)

    Lee, S. K.; Beard, C. A.; Wilson, W. B.; Daemen, L. L.; Liska, D. J.; Waters, L. S.; Adams, M. L.

    1995-01-01

    For the new, high-power accelerators currently being designed, the amount of activation of the accelerator structure has become an important issue. To quantify this activation, a methodology was utilized that coupled transport and depletion codes to obtain dose rate estimates at several locations near the accelerator. This research focused on the 20 and 100 MeV sections of the Bridge-Coupled Drift Tube Linear Accelerator. The peak dose rate was found to be approximately 6 mR/hr in the 100 MeV section near the quadrupoles at a 25-cm radius for an assumed beam loss of 1 nA/m. It was determined that the activation was dominated by the proton interactions and subsequent spallation product generation, as opposed to the presence of the generated neutrons. The worst contributors were the spallation products created by proton bombardment of iron, and the worst component was the beam pipe, which consists mostly of iron. No definitive conclusions about the feasibility of hands-on maintenance can be determined, as the design is still not finalized

  11. Structural activation calculations due to proton beam loss in the APT accelerator design

    International Nuclear Information System (INIS)

    Lee, S.K.; Beard, C.A.; Wilson, W.B.; Daemen, L.L.; Liska, D.J.; Waters, L.S.; Adams, M.L.

    1994-01-01

    For the new, high-power accelerators currently being designed, the amount of activation of the accelerator structure has become an important issue. To quantify this activation, a methodology was utilized that coupled transport and depletion codes to obtain dose rate estimates at several locations near the accelerator. This research focused on the 20 and 100 MeV sections of the Bridge-Coupled Drift Tube Linear Accelerator. The peak dose rate was found to be approximately 6 mR/hr in the 100 MeV section near the quadrupoles at a 25-cm radius for an assumed beam loss of 1 nA/m. It was determined that the activation was dominated by the proton interactions and subsequent spallation product generation, as opposed to the presence of the generated neutrons. The worst contributors were the spallation products created by proton bombardment of iron, and the worst component was the beam pipe, which consists mostly of iron. No definitive conclusions about the feasibility of hands-on maintenance can be determined, as the design is still not finalized

  12. Differential equation of transverse vibrations of a beam with local stroke change of stiffness

    Directory of Open Access Journals (Sweden)

    Stanisław Kasprzyk

    2007-01-01

    Full Text Available The aim of this paper is to derive a differential equation of transverse vibrations of a beam with a local, stroke change of stiffness, and to solve it. The presented method is based on the theory of distributions.

  13. Individually controlled localized chilled beam in conjunction with chilled ceiling: Part 1 – Physical environment

    DEFF Research Database (Denmark)

    Arghand, Taha; Bolashikov, Zhecho Dimitrov; Kosonen, Risto

    2016-01-01

    This study investigates the indoor environment generated by localized chilled beam coupled with chilled ceiling (LCBCC) and compares it with the environment generated by mixing ventilation coupled with chilled ceiling (CCMV). The experiments were performed in a mock-up of single office (4.1 m × 4...

  14. Multi-flexural band gaps in an Euler–Bernoulli beam with lateral local resonators

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ting, E-mail: WT323@mail.nwpu.edu.cn [School of Marine Science and Technology, Northwestern Polytechnical University, Xi' an, Shaanxi, 710072 (China); College of Engineering and Computer Science, The Australian National University, ACT, 2600 (Australia); Sheng, Mei-Ping [School of Marine Science and Technology, Northwestern Polytechnical University, Xi' an, Shaanxi, 710072 (China); Qin, Qing-Hua [College of Engineering and Computer Science, The Australian National University, ACT, 2600 (Australia)

    2016-02-05

    Flexural vibration suppression in an Euler–Bernoulli beam with attached lateral local resonators (LLR) is studied theoretically and numerically. Hamilton's principle and Bloch's theorem are employed to derive the dispersion relation which reveals that two band gaps are generated. Within both band gaps, the flexural waves are partially transformed into longitudinal waves through a four-link-mechanism and totally blocked. The band gaps can be flexibly tuned by changing the geometry parameter of the four-link-mechanism and the spring constants of the resonators. Frequency response function (FRF) from finite element analysis via commercial software of ANSYS shows large flexural wave attenuation within the band gaps and the effect of damping from the LLR substructures which helps smooth and lower the response peaks at the sacrifice of the band gap effect. The existence of the multi-flexural band gaps can be exploited for the design of flexural vibration control of beams. - Highlights: • A metamaterial beam with lateral local resonance is proposed. • The metamaterial beam can generate multi-band gaps for flexural wave suppression. • The substructure can transform the flexural wave into longitudinal wave and absorb the waves. • Damping from different part has different influence on the band gaps. • The design of the metamaterial beam can be used for multi-flexural vibration control.

  15. Results of external beam irradiation for rectal carcinomas locally recurrent after local excision or electrocoagulation

    International Nuclear Information System (INIS)

    Shun Wong, C.; Cummings, B.J.; Keane, T.J.; O'Sullivan, Brian; Catton, C.N.

    1991-01-01

    The outcome of 42 patients who developed locally recurrent rectal carcinoma after initial local excision or electrocoagulation was presented. Five patients received combined surgery and radiotherapy (XRT). The remaining 37 patients were managed by XRT alone. The overall 5 years actuarial survival and local control rates were 21 and 22 percent, respectively. For patients who received XRT alone, the 5 year actuarial survival and local control rates were 20 and 15 percent, resp. The corresponding figures were 35 and 40 percent for patients who received a total XRT dose of 50 Gy or more. One patient who underwent combined treatment developed rectal and bladder incontinence requiring surgery. For patients with rectal recurrence after initial conservative surgery, XRT is an alternative to abdominoperipheral resection if major resection is contraindicated. (author). 13 refs.; 2 tabs

  16. Automatic local beam steering systems for NSLS x-ray storage ring: Design and implementation

    International Nuclear Information System (INIS)

    Singh, O.V.; Nawrocky, R.; Flannigan, J.

    1991-01-01

    Recently, two local automatic steering systems, controlled by microprocessors, have been installed and commissioned in the NSLS X- Ray storage ring. In each system, the position of the electron beam is stabilized at two locations by four independent servo systems. This paper describes three aspects of the local feedback program: design; commissioning; and limitation. The system design is explained by identifying major elements such as beam position detectors, signal processors, compensation amplifiers, ratio amplifiers, trim equalizers and microprocessor feedback controllers. System commissioning involves steps such as matching trim compensation, determination of local orbit bumps, measurement of open loop responses and design of servo circuits. Several limitations of performance are also discussed. 7 refs., 2 figs

  17. New data acquisition system for beam loss monitor used in J-PARC main ring

    Science.gov (United States)

    Satou, K.; Toyama, T.; Kamikubota, N.; Yoshida, S.; Matsushita, J.; Wakita, T.; Sugiyama, M.; Morino, T.

    2018-04-01

    A new data acquisition system has been developed continually as a part of the development of a new beam loss monitor (BLM) system for the J-PARC main ring. This development includes a newly designed front-end isolation amp that uses photo-couplers and a VME-based new analog-to-digital converter (ADC) system. Compared to the old amp, the new amp has a 10 times higher conversion impedance for the input current to the output voltage; this value is 1 M Ω. Moreover, the bandwidth was improved to from DC to 50 kHz, which is about two orders of magnitude greater than the previously used bandwidth. The theoretical estimations made in this study roughly agree with the frequency response obtained for the new system. The new ADC system uses an on-board field-programmable gate array chip for signal processing. By replacing the firmware of this chip, changes pertaining to future accelerator upgrade plans may be introduced into the new ADC system; in addition, the ADC system can be used in other applications. The sampling speed of the system is 1 MS/s, and it exhibits a 95 dBc spurious-free dynamic range and 16.5 effective number of bits. The obtained waveform and integrated charge data are compared with two reference levels in the ADC system. If the data exceeds the reference level, the system generates an alarm to dump the beams. By using the new data acquisition system, it was proved that the new BLM system shows a wide dynamic range of 160 dB. In this study, the details of the new data acquisition system are described.

  18. OPERATIONAL EXPERIENCE WITH FAST FIBER-OPTIC BEAM LOSS MONITORS FOR THE ADVANCED PHOTON SOURCE STORAGE RING SUPERCONDUCTING UNDULATORS

    Energy Technology Data Exchange (ETDEWEB)

    Dooling, J.; Harkay, K.; Sajaev, V.; Shang, H.

    2017-06-25

    Fast fiber-optic (FFO) beam loss monitors (BLMs) installed with the first two superconducting undulators (SCUs) in the Advanced Photon Source storage ring have proven to be a useful diagnostic for measuring deposited charge (energy) during rapid beam loss events. The first set of FFOBLMs were installed outside the cryostat of the short SCU, a 0.33-m long device, above and below the beam centerline. The second set are mounted with the first 1.1-mlong SCU within the cryostat, on the outboard and inboard sides of the vacuum chamber. The next 1.1-m-long SCU is scheduled to replace the short SCU later in 2016 and will be fitted with FFOBLMs in a manner similar to original 1.1-m device. The FFOBLMs were employed to set timing and voltage for the abort kicker (AK) system. The AK helps to prevent quenching of the SCUs during beam dumps [1] by directing the beam away from the SC magnet windings. The AK is triggered by the Machine Protection System (MPS). In cases when the AK fails to prevent quenching, the FFOBLMs show that losses often begin before detection by the MPS.

  19. Displaying Voter Gains and Losses: Local Government Elections in South Africa for 2011 and 2016

    CSIR Research Space (South Africa)

    Schmitz, Peter MU

    2017-05-01

    Full Text Available of voter behavior between two subsequent local government elections from 2011 and 2016. The percentage voter gains and losses for the top three political parties in South Africa are shown. In the election of 2016, the ruling African National Congress (ANC...

  20. High-sensitivity visualization of localized electric fields using low-energy electron beam deflection

    Science.gov (United States)

    Jeong, Samuel; Ito, Yoshikazu; Edwards, Gary; Fujita, Jun-ichi

    2018-06-01

    The visualization of localized electronic charges on nanocatalysts is expected to yield fundamental information about catalytic reaction mechanisms. We have developed a high-sensitivity detection technique for the visualization of localized charges on a catalyst and their corresponding electric field distribution, using a low-energy beam of 1 to 5 keV electrons and a high-sensitivity scanning transmission electron microscope (STEM) detector. The highest sensitivity for visualizing a localized electric field was ∼0.08 V/µm at a distance of ∼17 µm from a localized charge at 1 keV of the primary electron energy, and a weak local electric field produced by 200 electrons accumulated on the carbon nanotube (CNT) apex can be visualized. We also observed that Au nanoparticles distributed on a CNT forest tended to accumulate a certain amount of charges, about 150 electrons, at a ‑2 V bias.

  1. Data evaluation and CNGS beam localization with the precision tracker of the OPERA detector

    International Nuclear Information System (INIS)

    Bick, D.

    2007-04-01

    In this diploma thesis, the data evaluation for the OPERA precision tracker is presented. Furthermore investigations of a precise CNGS beam localization with the precision tracker are performed. After an overview of past and present developments in neutrino physics, the OPERA detector is presented in this thesis. Emphasis is given to the precision tracker which has been partly commissioned in the end of the last year. A first analysis of the functionality with cosmic muons has been performed, as well as the inclusion of data in the OPERA software framework. Within this thesis some useful tools have been developed which are also presented. Finally, divergence effects from the nominal beam line of the CNGS neutrino beam and possible detection with the precision tracker are studied. (orig.)

  2. Data evaluation and CNGS beam localization with the precision tracker of the OPERA detector

    Energy Technology Data Exchange (ETDEWEB)

    Bick, D.

    2007-04-15

    In this diploma thesis, the data evaluation for the OPERA precision tracker is presented. Furthermore investigations of a precise CNGS beam localization with the precision tracker are performed. After an overview of past and present developments in neutrino physics, the OPERA detector is presented in this thesis. Emphasis is given to the precision tracker which has been partly commissioned in the end of the last year. A first analysis of the functionality with cosmic muons has been performed, as well as the inclusion of data in the OPERA software framework. Within this thesis some useful tools have been developed which are also presented. Finally, divergence effects from the nominal beam line of the CNGS neutrino beam and possible detection with the precision tracker are studied. (orig.)

  3. Human response to individually controlled micro environment generated with localized chilled beam

    DEFF Research Database (Denmark)

    Uth, Simon C.; Nygaard, Linette; Bolashikov, Zhecho Dimitrov

    2014-01-01

    Indoor environment in a single-office room created by a localised chilled beam with individual control of the primary air flow was studied. Response of 24 human subjects when exposed to the environment generated by the chilled beam was collected via questionnaires under a 2-hour exposure including...... and local thermal sensation reported by the subjects with the two systems. Both systems were equally acceptable. At 26°C the individual control of the localised chilled beam lead to higher acceptability of the work environment. At 28°C the acceptability decreased with the two systems. It was not acceptable...... different work tasks at three locations in the room. Response of the subjects to the environment generated with a chilled ceiling combined with mixing air distribution was used for comparison. The air temperature in the room was kept at 26 or 28 °C. Results show no significant difference in the overall...

  4. Dynamics of many-body localization in the presence of particle loss

    Science.gov (United States)

    van Nieuwenburg, EPL; Yago Malo, J.; Daley, AJ; Fischer, MH

    2018-01-01

    At long times, residual couplings to the environment become relevant even in the most isolated experiments, a crucial difficulty for the study of fundamental aspects of many-body dynamics. A particular example is many-body localization in a cold-atom setting, where incoherent photon scattering introduces both dephasing and particle loss. Whereas dephasing has been studied in detail and is known to destroy localization already on the level of non-interacting particles, the effect of particle loss is less well understood. A difficulty arises due to the ‘non-local’ nature of the loss process, complicating standard numerical tools using matrix product decomposition. Utilizing symmetries of the Lindbladian dynamics, we investigate the particle loss on both the dynamics of observables, as well as the structure of the density matrix and the individual states. We find that particle loss in the presence of interactions leads to dissipation and a strong suppression of the (operator space) entanglement entropy. Our approach allows for the study of the interplay of dephasing and loss for pure and mixed initial states to long times, which is important for future experiments using controlled coupling of the environment.

  5. Stabilization analysis of Euler-Bernoulli beam equation with locally distributed disturbance

    Directory of Open Access Journals (Sweden)

    Pengcheng HAN

    2017-12-01

    Full Text Available In order to enrich the system stability theory of the control theories, taking Euler-Bernoulli beam equation as the research subject, the stability of Euler-Bernoulli beam equation with locally distributed disturbance is studied. A feedback controller based on output is designed to reduce the effects of the disturbances. The well-posedness of the nonlinear closed-loop system is investigated by the theory of maximal monotone operator, namely the existence and uniqueness of solutions for the closed-loop system. An appropriate state space is established, an appropriate inner product is defined, and a non-linear operator satisfying this state space is defined. Then, the system is transformed into the form of evolution equation. Based on this, the existence and uniqueness of solutions for the closed-loop system are proved. The asymptotic stability of the system is studied by constructing an appropriate Lyapunov function, which proves the asymptotic stability of the closed-loop system. The result shows that designing proper anti-interference controller is the foundation of investigating the system stability, and the research of the stability of Euler-bernoulli beam equation with locally distributed disturbance can prove the asymptotic stability of the system. This method can be extended to study the other equations such as wave equation, Timoshenko beam equation, Schrodinger equation, etc.

  6. Localized conductive patterning via focused electron beam reduction of graphene oxide

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Songkil; Henry, Mathias [George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); Kulkarni, Dhaval D.; Zackowski, Paul; Jang, Seung Soon; Tsukruk, Vladimir V. [School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); Fedorov, Andrei G., E-mail: agf@gatech.edu [George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States)

    2015-03-30

    We report on a method for “direct-write” conductive patterning via reduction of graphene oxide (GO) sheets using focused electron beam induced deposition (FEBID) of carbon. FEBID treatment of the intrinsically dielectric graphene oxide between two metal terminals opens up the conduction channel, thus enabling a unique capability for nanoscale conductive domain patterning in GO. An increase in FEBID electron dose results in a significant increase of the domain electrical conductivity with improving linearity of drain-source current vs. voltage dependence, indicative of a change of graphene oxide electronic properties from insulating to semiconducting. Density functional theory calculations suggest a possible mechanism underlying this experimentally observed phenomenon, as localized reduction of graphene oxide layers via interactions with highly reactive intermediates of electron-beam-assisted dissociation of surface-adsorbed hydrocarbon molecules. These findings establish an unusual route for using FEBID as nanoscale lithography and patterning technique for engineering carbon-based nanomaterials and devices with locally tailored electronic properties.

  7. Luminosity, Beamstrahlung energy loss and beam-beam deflections for e{sup +}e{sup -} and e{sup -}e{sup -} collisions at the ILC with 500 GeV and varying transverse beam sizes

    Energy Technology Data Exchange (ETDEWEB)

    Alabau Pons, M. [Laboratoire de l' Accelerateur Lineaire, IN2P3-CNRS et Universite de Paris-Sud XI, Bat. 200, B.P. 34, 91898 Orsay Cedex (France)]|[IFIC, Edificio Institutos de Paterna, Aptdo. 22085, 46071 Valencia (Spain); Bambade, P. [Laboratoire de l' Accelerateur Lineaire, IN2P3-CNRS et Universite de Paris-Sud XI, Bat. 200, B.P. 34, 91898 Orsay Cedex (France); Faus-Golfe, A. [IFIC, Edificio Institutos de Paterna, Aptdo. 22085, 46071 Valencia (Spain)

    2006-01-15

    At the interaction point of the International Linear Collider, beam-beam effects due to the strong electromagnetic fields that the bunches experience during collisions cause a mutual focusing, called pinch effect, which enhances the luminosity in the case of e{sup +}e{sup -} collisions. The opposite is true for e{sup -}e{sup -} collisions. In this case the luminosity is reduced by mutual defocusing, or anti-pinching. The resulting Beamstrahlung energy loss and beam-beam deflection angles as function of the vertical transverse offset are also different for both modes of operation. The dependence of these quantities with transverse beam sizes are presented for the case of e{sup -}e{sup -} collisions.

  8. Electron Beam Return-Current Losses in Solar Flares: Initial Comparison of Analytical and Numerical Results

    Science.gov (United States)

    Holman, Gordon

    2010-01-01

    Accelerated electrons play an important role in the energetics of solar flares. Understanding the process or processes that accelerate these electrons to high, nonthermal energies also depends on understanding the evolution of these electrons between the acceleration region and the region where they are observed through their hard X-ray or radio emission. Energy losses in the co-spatial electric field that drives the current-neutralizing return current can flatten the electron distribution toward low energies. This in turn flattens the corresponding bremsstrahlung hard X-ray spectrum toward low energies. The lost electron beam energy also enhances heating in the coronal part of the flare loop. Extending earlier work by Knight & Sturrock (1977), Emslie (1980), Diakonov & Somov (1988), and Litvinenko & Somov (1991), I have derived analytical and semi-analytical results for the nonthermal electron distribution function and the self-consistent electric field strength in the presence of a steady-state return-current. I review these results, presented previously at the 2009 SPD Meeting in Boulder, CO, and compare them and computed X-ray spectra with numerical results obtained by Zharkova & Gordovskii (2005, 2006). The phYSical significance of similarities and differences in the results will be emphasized. This work is supported by NASA's Heliophysics Guest Investigator Program and the RHESSI Project.

  9. Low-resistance strip sensors for beam-loss event protection

    International Nuclear Information System (INIS)

    Ullán, M.; Benítez, V.; Quirion, D.; Zabala, M.; Pellegrini, G.; Lozano, M.; Lacasta, C.; Soldevila, U.; García, C.; Fadeyev, V.; Wortman, J.; DeFilippis, J.; Shumko, M.; Grillo, A.A; Sadrozinski, H.F.-W.

    2014-01-01

    AC-coupled silicon strip sensors can be damaged in case of a beam loss due to the possibility of a large charge accumulation in the bulk, developing very high voltages across the coupling capacitors which can destroy them. Punch-through structures are currently used to avoid this problem helping to evacuate the accumulated charge as large voltages are developing. Nevertheless, previous experiments, performed with laser pulses, have shown that these structures can become ineffective in relatively long strips. The large value of the implant resistance can effectively isolate the “far” end of the strip from the punch-through structure leading to large voltages. We present here our developments to fabricate low-resistance strip sensors to avoid this problem. The deposition of a conducting material in contact with the implants drastically reduces the strip resistance, assuring the effectiveness of the punch-through structures. First devices have been fabricated with this new technology. Initial results with laser tests show the expected reduction in peak voltages on the low resistivity implants. Other aspects of the sensor performance, including the signal formation, are not affected by the new technology

  10. Global and Local Loss Suppression in the UA9 Crystal Collimation Experiment

    CERN Document Server

    Montesano, S

    2012-01-01

    UA9 was operated in the CERN-SPS for some years in view of investigating the feasibility of the halo collimation assisted by bent crystals. Silicon crystals 2 mm long with bending angles of about 150 μrad are used as primary collimators. The crystal collimation process is obtained consistently through channeling with high efficiency. The loss profiles in the area of the crystal collimator setup and in the downstream dispersion suppressor area show a steady reduction of slightly less than one order of magnitude at the onset of the channeling process. This result holds both for protons and for lead ions. The corresponding loss map in the accelerator ring is accordingly reduced. These observations strongly support our expectation that the coherent deflection of the beam halo by a bent crystal should enhance the collimation efficiency in hadron colliders, such as LHC.

  11. Localization of Transversal Cracks in Sandwich Beams and Evaluation of Their Severity

    Directory of Open Access Journals (Sweden)

    G. R. Gillich

    2014-01-01

    Full Text Available An algorithm to assess transversal cracks in composite structures based on natural frequency changes due to damage is proposed. The damage assessment is performed in two steps; first the crack location is found, and afterwards an evaluation of its severity is performed. The technique is based on a mathematical relation that provides the exact solution for the frequency changes of bending vibration modes, considering two terms. The first term is related to the strain energy stored in the beam, while the second term considers the increase of flexibility due to damage. Thus, it is possible to separate the problems of localization and severity assessment, which makes the localization process independent of the beams cross-section shape and boundary conditions. In fact, the process consists of comparing vectors representing the measured frequency shifts with patterns constructed using the mode shape curvatures of the undamaged beam. Once the damage is localized, the evaluation of its severity is made taking into account the global rigidity reduction. The damage identification algorithm was validated by experiments performed on numerous sandwich panel specimens.

  12. Beam losses from ultra-peripheral nuclear collisions between $^{208}$Pb$^{82+}$ ions in the Large Hadron Collider and their alleviation

    CERN Document Server

    Bruce, R.; Jowett, J.M.; Bocian, D.; CERN. Geneva. BE Department

    2009-01-01

    Electromagnetic interactions between colliding heavy ions at the Large Hadron Collider (LHC) at CERN will give rise to localized beam losses that may quench superconducting magnets, apart from contributing significantly to the luminosity decay. To quantify their impact on the operation of the collider, we have used a three-step simulation approach, which consists of optical tracking, a Monte-Carlo shower simulation and a thermal network model of the heat flow inside a magnet. We present simulation results for the case of Pb ion operation in the LHC, with focus on the ALICE interaction region, and show that the expected heat load during nominal Pb operation is 40% above the quench level. This limits the maximum achievable luminosity. Furthermore, we discuss methods of monitoring the losses and possible ways to alleviate their effect.

  13. Local vibration enhanced the efficacy of passive exercise on mitigating bone loss in hindlimb unloading rats

    Science.gov (United States)

    Huang, Yunfei; Luan, Huiqin; Sun, Lianwen; Bi, Jingfang; Wang, Ying; Fan, Yubo

    2017-08-01

    Spaceflight induced bone loss is seriously affecting astronauts. Mechanical stimulation from exercise has been shown to restrain bone resorption as well as improve bone formation. Current exercise countermeasures in space cannot prevent it completely. Active exercise may convert to passive exercise in some ways because of the loss of gravity stimulus and inertia of exercise equipment. The aim of this study was to compare the efficacy of passive exercise or/and local vibration on counteracting the deterioration of the musculoskeletal system, including bone, muscle and tendons in tail-suspended rats. We hypothesized that local vibration could enhance the efficacy of passive exercise on countering bone loss. 40 Sprague Dawley rats were randomly distributed into five groups (n = 8, each): tail-suspension (TS), TS+35 Hz vibration (TSV), TS + passive exercise (TSP), TS + passive exercise coupled with 35 Hz vibration (TSPV) and control (CON). Passive exercise or/and local vibration was performed for 21 days. On day 0 and 21, bone mineral density (BMD) was observed by dual energy X-ray absorptiometry (DXA), and trabecular microstructure was evaluated by microcomputer tomography (μCT) analysis in vivo. Mechanical properties of tibia and tendon were determined by a mechanical testing system. Soleus and bone ash weight was tested by an electronic balance. Results showed that the passive exercise could not prevent the decrease of trabecular BMD, microstructure and bone ash weight induced by TS, whereas vibration and passive exercise coupled with local vibration (PV) could. Biomechanical properties of the tibia and tendon in TSPV group significantly increased compared with TS group. In summary, PV in this study was the best method in preventing weightlessness-induced bone loss. Consistent with our hypothesis, local vibration partly enhanced the effect of passive exercise. Furthermore, this study will be useful in improving countermeasure for astronauts, but also for the

  14. SU-F-J-11: Radiobiologically Optimized Patient Localization During Prostate External Beam Localization

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Y; Gardner, S; Liu, C; Zhao, B; Wen, N; Brown, S; Chetty, I [Henry Ford Health System, Detroit, MI (United States)

    2016-06-15

    Purpose: To present a novel positioning strategy which optimizes radiation delivery with radiobiological response knowledge, and to evaluate its application during prostate external beam radiotherapy. Methods: Ten patients with low or intermediate risk prostate cancer were evaluated retrospectively in this IRB-approved study. For each patient, a VMAT plan was generated on the planning CT (PCT) to deliver 78 Gy in 39 fractions with PTV = prostate + 7 mm margin, except for 5mm in the posterior direction. Five representative pretreatment CBCT images were selected for each patient, and prostate, rectum, and bladder were delineated on all CBCT images. Each CBCT was auto-registered to the corresponding PCT. Starting from this auto-matched position (AM-position), a search for optimal treatment position was performed utilizing a score function based on radiobiological and dosimetric indices (D98-DTV, NTCP-rectum, and NTCP-bladder) for the daily target volume (DTV), rectum, and bladder. DTV was defined as prostate + 4 mm margin to account for intra-fraction motion as well as contouring variability on CBCT. We termed the optimal treatment position the radiobiologically optimized couch shift position (ROCS-position). Results: The indices, averaged over the 10 patients’ treatment plans, were (mean±SD): 77.7±0.2 Gy (D98-PTV), 12.3±2.7% (NTCP-rectum), and 53.2±11.2% (NTCP-bladder). The corresponding values calculated on all 50 CBCT images at the AM-positions were 72.9±11.3 Gy (D98-DTV), 15.8±6.4% (NTCP-rectum), and 53.0±21.1% (NTCP-bladder), respectively. In comparison, calculated on CBCT at the ROCS-positions, the indices were 77.0±2.1 Gy (D98-DTV), 12.1±5.7% (NTCP-rectum), and 60.7±16.4% (NTCP-bladder). Compared to autoregistration, ROCS-optimization recovered dose coverage to target volume and lowered the risk to rectum. Moreover, NTCPrectum for one patient remained high after ROCS-optimization and therefore could potentially benefit from adaptive planning

  15. Effect of Local Junction Losses in the Optimization of T-shaped Flow Channels

    Science.gov (United States)

    Kosaraju, Srinivas

    2015-11-01

    T-shaped channels are extensively used in flow distribution applications such as irrigation, chemical dispersion, gas pipelines and space heating and cooling. The geometry of T-shaped channels can be optimized to reduce the overall pressure drop in stem and branch sections. Results of such optimizations are in the form of geometric parameters such as the length and diameter ratios of the stem and branch sections. The traditional approach of this optimization accounts for the pressure drop across the stem and branch sections, however, ignores the pressure drop in the T-junction. In this paper, we conduct geometry optimization while including the effect of local junction losses in laminar flows. From the results, we are able to identify a non-dimensional parameter that can be used to predict the optimal geometric configurations. This parameter can also be used to identify the conditions in which the local junction losses can be ignored during the optimization.

  16. Tests of Local Hadron Calibration Approaches in ATLAS Combined Beam Tests

    International Nuclear Information System (INIS)

    Grahn, Karl-Johan; Kiryunin, Andrey; Pospelov, Guennadi

    2011-01-01

    Three ATLAS calorimeters in the region of the forward crack at |η| 3.2 in the nominal ATLAS setup and a typical section of the two barrel calorimeters at |η| = 0.45 of ATLAS have been exposed to combined beam tests with single electrons and pions. Detailed shower shape studies of electrons and pions with comparisons to various Geant4 based simulations utilizing different physics lists are presented for the endcap beam test. The local hadron calibration approach as used in the full Atlas setup has been applied to the endcap beam test data. An extension of it using layer correlations has been tested with the barrel test beam data. Both methods utilize modular correction steps based on shower shape variables to correct for invisible energy inside the reconstructed clusters in the calorimeters (compensation) and for lost energy deposits outside of the reconstructed clusters (dead material and out-of-cluster deposits). Results for both methods and comparisons to Monte Carlo simulations are presented.

  17. Laser beam deflection-based perimeter scanning of integrated circuits for local overheating location

    International Nuclear Information System (INIS)

    Perpina, X; Jorda, X; Vellvehi, M; Altet, J; Mestres, N

    2009-01-01

    In integrated circuits, local overheating (hot spots) can be detected by monitoring the temperature gradients present in the silicon substrate at a given depth, laterally accessing the die with an infra-red laser beam probe. The sensed magnitude is the laser beam deflection, which is proportional to the temperature gradients found along the beam trajectory (mirage effect). Biasing the devices with periodic electrical functions allows employing lock-in detection strategies (noise immunity) and thermally isolating the analysed chip substrate thermal behaviour from the external boundary conditions by setting the excitation frequency (control of the thermal energy penetration depth). Measuring the first harmonic of the deflection signal components (vertical and horizontal) allows performing a fast and accurate location of devices, interconnects or circuits dissipating relatively high power levels without any calibration procedure. It has been concluded that the horizontal component of the beam deflection provides a higher spatial resolution than the vertical one when measurements are performed beyond the thermal energy penetration depth. (fast track communication)

  18. Local Residents Perception of Benefits and Losses From Protected Areas in India and Nepal

    Science.gov (United States)

    Karanth, Krithi K.; Nepal, Sanjay K.

    2012-02-01

    High densities of people living around protected areas (PAs) in South Asia require management strategies to balance conservation goals and livelihood needs. Based on a survey of 777 households around five PAs in India and Nepal, this paper provides a comparative perspective of Indian and Nepali households' views of protected area benefits and costs, their attitude toward conservation in general, and attitude toward protected area staff. Results indicate mixed responses towards tourism, varying from very favorable in Nepal to less favorable in India. The majority (81%) held positive attitudes towards the existence and importance of PAs but had negative perceptions of PA staff (69%). Most residents perceived benefits from access to fuel wood, fodder and other PA resources including benefits from tourism, while crop and livestock losses from wildlife were the main costs. Households overall positive attitudes towards the PAs and conservation despite high losses from living around PAs suggests that local residents may support conservation if their livelihood needs are met. Comparisons of household attitudes and perceptions suggest that locally based strategies rather than top-down approaches are likely to be more effective. Extending PA benefits to smaller landholders, households that are highly resource-dependent or experiencing higher income losses from human-wildlife conflicts, and less educated residents are particularly important to balance costs and losses from living around protected areas.

  19. Sound Localization in Patients With Congenital Unilateral Conductive Hearing Loss With a Transcutaneous Bone Conduction Implant.

    Science.gov (United States)

    Vyskocil, Erich; Liepins, Rudolfs; Kaider, Alexandra; Blineder, Michaela; Hamzavi, Sasan

    2017-03-01

    There is no consensus regarding the benefit of implantable hearing aids in congenital unilateral conductive hearing loss (UCHL). This study aimed to measure sound source localization performance in patients with congenital UCHL and contralateral normal hearing who received a new bone conduction implant. Evaluation of within-subject performance differences for sound source localization in a horizontal plane. Tertiary referral center. Five patients with atresia of the external auditory canal and contralateral normal hearing implanted with transcutaneous bone conduction implant at the Medical University of Vienna were tested. Activated/deactivated implant. Sound source localization test; localization performance quantified using the root mean square (RMS) error. Sound source localization ability was highly variable among individual subjects, with RMS errors ranging from 21 to 40 degrees. Horizontal plane localization performance in aided conditions showed statistically significant improvement compared with the unaided conditions, with RMS errors ranging from 17 to 27 degrees. The mean RMS error decreased by a factor of 0.71 (p conduction implant. Some patients with congenital UCHL might be capable of developing improved horizontal plane localization abilities with the binaural cues provided by this device.

  20. Local Recurrence After Uveal Melanoma Proton Beam Therapy: Recurrence Types and Prognostic Consequences

    Energy Technology Data Exchange (ETDEWEB)

    Caujolle, Jean-Pierre, E-mail: ncaujolle@aol.com [Department of Ophthalmology, Saint Roch Hospital, Nice Teaching Hospital, Nice (France); Paoli, Vincent [Department of Ophthalmology, Saint Roch Hospital, Nice Teaching Hospital, Nice (France); Chamorey, Emmanuel [Department of Radiation Oncology, Protontherapy Center, Centre Antoine Lacassagne, Nice (France); Department of Biostatistics and Epidemiology, Centre Antoine Lacassagne, Nice (France); Maschi, Celia; Baillif, Stéphanie [Department of Ophthalmology, Saint Roch Hospital, Nice Teaching Hospital, Nice (France); Herault, Joël [Department of Radiation Oncology, Protontherapy Center, Centre Antoine Lacassagne, Nice (France); Gastaud, Pierre [Department of Ophthalmology, Saint Roch Hospital, Nice Teaching Hospital, Nice (France); Hannoun-Levi, Jean Michel [Department of Radiation Oncology, Protontherapy Center, Centre Antoine Lacassagne, Nice (France)

    2013-04-01

    Purpose: To study the prognosis of the different types of uveal melanoma recurrences treated by proton beam therapy (PBT). Methods and Materials: This retrospective study analyzed 61 cases of uveal melanoma local recurrences on a total of 1102 patients treated by PBT between June 1991 and December 2010. Survival rates have been determined by using Kaplan-Meier curves. Prognostic factors have been evaluated by using log-rank test or Cox model. Results: Our local recurrence rate was 6.1% at 5 years. These recurrences were divided into 25 patients with marginal recurrences, 18 global recurrences, 12 distant recurrences, and 6 extrascleral extensions. Five factors have been identified as statistically significant risk factors of local recurrence in the univariate analysis: large tumoral diameter, small tumoral volume, low ratio of tumoral volume over eyeball volume, iris root involvement, and safety margin inferior to 1 mm. In the local recurrence-free population, the overall survival rate was 68.7% at 10 years and the specific survival rate was 83.6% at 10 years. In the local recurrence population, the overall survival rate was 43.1% at 10 years and the specific survival rate was 55% at 10 years. The multivariate analysis of death risk factors has shown a better prognosis for marginal recurrences. Conclusion: Survival rate of marginal recurrences is superior to that of the other recurrences. The type of recurrence is a clinical prognostic value to take into account. The influence of local recurrence retreatment by proton beam therapy should be evaluated by novel studies.

  1. Local Recurrence After Uveal Melanoma Proton Beam Therapy: Recurrence Types and Prognostic Consequences

    International Nuclear Information System (INIS)

    Caujolle, Jean-Pierre; Paoli, Vincent; Chamorey, Emmanuel; Maschi, Celia; Baillif, Stéphanie; Herault, Joël; Gastaud, Pierre; Hannoun-Levi, Jean Michel

    2013-01-01

    Purpose: To study the prognosis of the different types of uveal melanoma recurrences treated by proton beam therapy (PBT). Methods and Materials: This retrospective study analyzed 61 cases of uveal melanoma local recurrences on a total of 1102 patients treated by PBT between June 1991 and December 2010. Survival rates have been determined by using Kaplan-Meier curves. Prognostic factors have been evaluated by using log-rank test or Cox model. Results: Our local recurrence rate was 6.1% at 5 years. These recurrences were divided into 25 patients with marginal recurrences, 18 global recurrences, 12 distant recurrences, and 6 extrascleral extensions. Five factors have been identified as statistically significant risk factors of local recurrence in the univariate analysis: large tumoral diameter, small tumoral volume, low ratio of tumoral volume over eyeball volume, iris root involvement, and safety margin inferior to 1 mm. In the local recurrence-free population, the overall survival rate was 68.7% at 10 years and the specific survival rate was 83.6% at 10 years. In the local recurrence population, the overall survival rate was 43.1% at 10 years and the specific survival rate was 55% at 10 years. The multivariate analysis of death risk factors has shown a better prognosis for marginal recurrences. Conclusion: Survival rate of marginal recurrences is superior to that of the other recurrences. The type of recurrence is a clinical prognostic value to take into account. The influence of local recurrence retreatment by proton beam therapy should be evaluated by novel studies

  2. Localization of metastable atom beams with optical standing waves: nanolithography at the heisenberg limit

    Science.gov (United States)

    Johnson; Thywissen; Dekker; Berggren; Chu; Younkin; Prentiss

    1998-06-05

    The spatially dependent de-excitation of a beam of metastable argon atoms, traveling through an optical standing wave, produced a periodic array of localized metastable atoms with position and momentum spreads approaching the limit stated by the Heisenberg uncertainty principle. Silicon and silicon dioxide substrates placed in the path of the atom beam were patterned by the metastable atoms. The de-excitation of metastable atoms upon collision with the surface promoted the deposition of a carbonaceous film from a vapor-phase hydrocarbon precursor. The resulting patterns were imaged both directly and after chemical etching. Thus, quantum-mechanical steady-state atom distributions can be used for sub-0.1-micrometer lithography.

  3. Calculation of abort thresholds for the Beam Loss Monitoring System of the Large Hadron Collider at CERN

    CERN Document Server

    Nemcic, Martin; Dehning, Bernd

    The Beam Loss Monitoring (BLM) System is one of the most critical machine protection systems for the Large Hadron Collider (LHC) at the European Organization for Nuclear Research (CERN), Switzerland. Its main purpose is to protect the superconducting magnets from quenches and other equipment from damage by requesting a beam abort when the measured losses exceed any of the predefined threshold levels. The system consist of circa 4000 ionization chambers which are installed around the 27 kilometres ring (LHC). This study aims to choose a technical platform and produce a system that addresses all of the limitations with the current system that is used for the calculation of the LHC BLM abort threshold values. To achieve this, a comparison and benchmarking of the Java and .NET technical platforms is performed in order to establish the most suitable solution. To establish which technical platform is a successful replacement of the current abort threshold calculator, comparable prototype systems in Java and .NET we...

  4. Comparison of three different concepts of high dynamic range and dependability optimised current measurement digitisers for beam loss systems

    CERN Document Server

    Viganò, W; Effinger, E; Venturini, G G; Zamantzas, C

    2012-01-01

    Three Different Concepts of High Dynamic Range and Dependability Optimised Current Measurement Digitisers for Beam Loss Systems will be compared on this paper. The first concept is based on Current to Frequency Conversion, enhanced with an ADC for extending the dynamic range and decreasing the response time. A summary of 3 years’ worth of operational experience with such a system for LHC beam loss monitoring will be given. The second principle is based on an Adaptive Current to Frequency Converter implemented in an ASIC. The basic parameters of the circuit are discussed and compared with measurements. Several measures are taken to harden both circuits against single event effects and to make them tolerant for operation in radioactive environments. The third circuit is based on a Fully Differential Integrator for enhanced dynamic range, where laboratory and test installation measurements will be presented. All circuits are designed to avoid any dead time in the acquisition and have reliability and fail safe...

  5. Dosimetric study of RapidArc plans with flattened beam (FB and flattening filter-free (FFF beam for localized prostate cancer based on physical indices

    Directory of Open Access Journals (Sweden)

    Birendra Kumar Rout

    2014-12-01

    Full Text Available Purpose: To identify the continual diversity between flattening photon beam (FB and Flattening Filter Free (FFF photon beams for localized prostate cancer; and to determine potential benefits and drawbacks of using unflattened beam for this type of treatment.Methods: Eight prostate cases including seminal vesicles selected for this study. The primary planning target volume (PTVP and boost planning target volume (PTVB were contoured. The total prescription dose was 78 Gy (56 Gy to PTVP and an additional 22 Gy to PTVB. For all cases, treatment plans using 6MV with FB and FFF beams with identical dose-volume constraints, arc angles and number of arcs were developed. The dose volume histograms for both techniques were compared for primary target volume and critical structures.Results: A low Sigma index (FFF: 1.65 + 0.361; FB: 1.725 + 0.39 indicating improved dose homogeneity in FFF beam. Conformity index (FFF: 0.994 + 0.01; FB: 0.993 + 0.01 is comparable for both techniques. Minimal difference of Organ at risk mean dose was observed. Normal tissue integral dose in FB plan resulted 1.5% lower than FFF plan. All the plans displayed significant increase (1.18 times for PTVP and 1.11 for PTBB in the average number of necessary MU with FFF beam.Conclusion: Diversity between FB and FFF beam plans were found. FFF beam accelerator has been utilized to develop clinically acceptable Rapid Arc treatment plans for prostate cancer with 6 MV.---------------------------------Cite this article as: Rout BK, Muralidhar KR, Ali M, Shekar MC, Kumar A. Dosimetric study of RapidArc plans with flattened beam (FB and flattening filter-free (FFF beam for localized prostate cancer based on physical indices. Int J Cancer Ther Oncol 2014; 2(4:02046.  DOI: 10.14319/ijcto.0204.6

  6. BEAM-LOSS DRIVEN DESIGN OPTIMIZATION FOR THE SPALLATION NEUTRON SOURCE (SNS) RING.

    Energy Technology Data Exchange (ETDEWEB)

    WEI,J.; BEEBE-WANG,J.; BLASKIEWICZ,M.; CAMERON,P.; DANBY,G.; GARDNER,C.J.; JACKSON,J.; LEE,Y.Y.; LUDEWIG,H.; MALITSKY,N.; RAPARIA,D.; TSOUPAS,N.; WENG,W.T.; ZHANG,S.Y.

    1999-03-29

    This paper summarizes three-stage design optimization for the Spallation Neutron Source (SNS) ring: linear machine design (lattice, aperture, injection, magnet field errors and misalignment), beam core manipulation (painting, space charge, instabilities, RF requirements), and beam halo consideration (collimation, envelope variation, e-p issues etc.).

  7. Beam-Loss Driven Design Optimization for the Spallation Neutron Source (SNS) Ring

    International Nuclear Information System (INIS)

    Wei, J.

    1999-01-01

    This paper summarizes three-state design optimization for the Spallation Neutron Source (SNS) ring: linear machine design (lattice, aperture, injection, magnet field errors and misalignment), beam core manipulation (painting, space charge, instabilities, RF requirements), and beam halo consideration (collimation, envelope variation, e-p issues etc.)

  8. A new approach for beam hardening correction based on the local spectrum distributions

    International Nuclear Information System (INIS)

    Rasoulpour, Naser; Kamali-Asl, Alireza; Hemmati, Hamidreza

    2015-01-01

    Energy dependence of material absorption and polychromatic nature of x-ray beams in the Computed Tomography (CT) causes a phenomenon which called “beam hardening”. The purpose of this study is to provide a novel approach for Beam Hardening (BH) correction. This approach is based on the linear attenuation coefficients of Local Spectrum Distributions (LSDs) in the various depths of a phantom. The proposed method includes two steps. Firstly, the hardened spectra in various depths of the phantom (or LSDs) are estimated based on the Expectation Maximization (EM) algorithm for arbitrary thickness interval of known materials in the phantom. The performance of LSD estimation technique is evaluated by applying random Gaussian noise to transmission data. Then, the linear attenuation coefficients with regarding to the mean energy of LSDs are obtained. Secondly, a correction function based on the calculated attenuation coefficients is derived in order to correct polychromatic raw data. Since a correction function has been used for the conversion of the polychromatic data to the monochromatic data, the effect of BH in proposed reconstruction must be reduced in comparison with polychromatic reconstruction. The proposed approach has been assessed in the phantoms which involve less than two materials, but the correction function has been extended for using in the constructed phantoms with more than two materials. The relative mean energy difference in the LSDs estimations based on the noise-free transmission data was less than 1.5%. Also, it shows an acceptable value when a random Gaussian noise is applied to the transmission data. The amount of cupping artifact in the proposed reconstruction method has been effectively reduced and proposed reconstruction profile is uniform more than polychromatic reconstruction profile. - Highlights: • A novel Beam Hardening (BH) correction approach was described. • A new concept named Local Spectrum Distributions (LSDs) was used to BH

  9. A new approach for beam hardening correction based on the local spectrum distributions

    Energy Technology Data Exchange (ETDEWEB)

    Rasoulpour, Naser; Kamali-Asl, Alireza, E-mail: a_kamali@sbu.ac.ir; Hemmati, Hamidreza

    2015-09-11

    Energy dependence of material absorption and polychromatic nature of x-ray beams in the Computed Tomography (CT) causes a phenomenon which called “beam hardening”. The purpose of this study is to provide a novel approach for Beam Hardening (BH) correction. This approach is based on the linear attenuation coefficients of Local Spectrum Distributions (LSDs) in the various depths of a phantom. The proposed method includes two steps. Firstly, the hardened spectra in various depths of the phantom (or LSDs) are estimated based on the Expectation Maximization (EM) algorithm for arbitrary thickness interval of known materials in the phantom. The performance of LSD estimation technique is evaluated by applying random Gaussian noise to transmission data. Then, the linear attenuation coefficients with regarding to the mean energy of LSDs are obtained. Secondly, a correction function based on the calculated attenuation coefficients is derived in order to correct polychromatic raw data. Since a correction function has been used for the conversion of the polychromatic data to the monochromatic data, the effect of BH in proposed reconstruction must be reduced in comparison with polychromatic reconstruction. The proposed approach has been assessed in the phantoms which involve less than two materials, but the correction function has been extended for using in the constructed phantoms with more than two materials. The relative mean energy difference in the LSDs estimations based on the noise-free transmission data was less than 1.5%. Also, it shows an acceptable value when a random Gaussian noise is applied to the transmission data. The amount of cupping artifact in the proposed reconstruction method has been effectively reduced and proposed reconstruction profile is uniform more than polychromatic reconstruction profile. - Highlights: • A novel Beam Hardening (BH) correction approach was described. • A new concept named Local Spectrum Distributions (LSDs) was used to BH

  10. Modeling of Local BEAM Structure for Evaluation of MMOD Impacts to Support Development of a Health Monitoring System

    Science.gov (United States)

    Lyle, Karen H.; Vassilakos, Gregory J.

    2015-01-01

    This report summarizes initial modeling of the local response of the Bigelow Expandable Activity Module (BEAM) to micrometeorite and orbital debris (MMOD) impacts using a structural, non-linear, transient dynamic finite element code. Complementary test results for a local BEAM structure are presented for both hammer and projectile impacts. Review of these data provided guidance for the transient dynamic model development. The local model is intended to support predictions using the global BEAM model, described in a companion report. Two types of local models were developed. One mimics the simplified Soft-Goods (fabric envelop) part of the BEAM NASTRAN model delivered by the project. The second investigates through-the-thickness modeling challenges for MMOD-type impacts. Both the testing and the analysis summaries contain lessons learned and areas for future efforts.

  11. Analysis of sub-bandgap losses in TiO2 coating deposited via single and dual ion beam deposition

    Czech Academy of Sciences Publication Activity Database

    Žídek, Karel; Hlubuček, Jiří; Horodyská, Petra; Budasz, Jiří; Václavík, Jan

    2017-01-01

    Roč. 626, March (2017), s. 60-65 ISSN 0040-6090 R&D Projects: GA MŠk(CZ) LO1206 Institutional support: RVO:61389021 Keywords : Ion beam deposition * Titanium dioxide * Optical coating * Sub-bandgap losses * Urbach tail Subject RIV: BH - Optics, Masers, Lasers OBOR OECD: Optics (including laser optics and quantum optics) Impact factor: 1.879, year: 2016 http://www.sciencedirect.com/science/article/pii/S0040609017301256

  12. Treatment of locally advanced breast carcinoma with high-dose external beam supervoltage radiotherapy

    International Nuclear Information System (INIS)

    Brufman, G.; Weshler, Z.; Prosnitz, L.R.; Fuks, Z.

    1981-01-01

    Between 1960 and 1978, 87 patients with locally advanced Tsub(3-4)Nsub(0-3)M 0 carcinoma of the breast were treated with 5,000 to 8,000 rad of external beam supervoltage radiotherapy. Initial clinical eradication of the tumour was observed in 76 of 87 cases (87%), but the actuarial probability of local control at 5 yr was only 53%. Furthermore, the actuarial probability of disease-free survival was 25% at 5 yr and 13% at 10 yr. Most of the patients eventually succumbed to metastatic breast carcinoma and the actuarial survival at 5 yr was 43% and at 10 yr, 16%. The addition of adjuvant low-dose chemotherapy, given to 13 patients, did not affect the rates of local control, survival or disease-free survival. The most common long-term complication was extensive and deforming radiation-induced fibrosis of the treated breast. The actuarial probability of 10-yr survival without a local recurrence and without severe fibrosis of the treated breast was only 17.5%. The role of adjuvant high-dose chemotherapy in the treatment of locally advanced breast carcinoma and the possible use of improved radiotherapy techniques to achieve a more effective long-term local control and a more desirable cosmetic end result are discussed. (author)

  13. A novel digitization scheme with FPGA-base TDC for beam loss monitors operating at cryogenic temperature

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Jinyuan; Warner, Arden; /Fermilab

    2011-11-01

    Recycling integrators are common current-to-frequency converting circuits for measurements of low current such as that produced by Fermilab's cryogenic ionization chambers. In typical digitization/readout schemes, a counter is utilized to accumulate the number of pulses generated by the recycling integrator to adequately digitize the total charge. In order to calculate current with reasonable resolution (e.g., 7-8 bits), hundreds of pulses must be accumulated which corresponds to a long sampling period, i.e., a very low sampling rate. In our new scheme, an FPGA-based Time-to-Digital Convertor (TDC) is utilized to measure the time intervals between the pulses output from the recycling integrator. Using this method, a sample point of the current can be made with good resolution (>10 bits) for each pulse. This effectively increases the sampling rates by hundreds of times for the same recycling integrator front-end electronics. This scheme provides a fast response to the beams loss and is potentially suitable for accelerator protection applications. Moreover, the method is also self-zero-suppressed, i.e., it produces more data when the beam loss is high while it produces significantly less data when the beam loss is low.

  14. Calculation of generalized Lorenz-Mie theory based on the localized beam models

    International Nuclear Information System (INIS)

    Jia, Xiaowei; Shen, Jianqi; Yu, Haitao

    2017-01-01

    It has been proved that localized approximation (LA) is the most efficient way to evaluate the beam shape coefficients (BSCs) in generalized Lorenz-Mie theory (GLMT). The numerical calculation of relevant physical quantities is a challenge for its practical applications due to the limit of computer resources. The study presents an improved algorithm of the GLMT calculation based on the localized beam models. The BSCs and the angular functions are calculated by multiplying them with pre-factors so as to keep their values in a reasonable range. The algorithm is primarily developed for the original localized approximation (OLA) and is further extended to the modified localized approximation (MLA). Numerical results show that the algorithm is efficient, reliable and robust. - Highlights: • In this work, we introduce the proper pre-factors to the Bessel functions, BSCs and the angular functions. With this improvement, all the quantities involved in the numerical calculation are scaled into a reasonable range of values so that the algorithm can be used for computing the physical quantities of the GLMT. • The algorithm is not only an improvement in numerical technique, it also implies that the set of basic functions involved in the electromagnetic scattering (and sonic scattering) can be reasonably chosen. • The algorithms of the GLMT computations introduced in previous references suggested that the order of the n and m sums is interchanged. In this work, the sum of azimuth modes is performed for each partial wave. This offers the possibility to speed up the computation, since the sum of partial waves can be optimized according to the illumination conditions and the sum of azimuth modes can be truncated by selecting a criterion discussed in . • Numerical results show that the algorithm is efficient, reliable and robust, even in very exotic cases. The algorithm presented in this paper is based on the original localized approximation and it can also be used for the

  15. Intensity-gradient induced Sisyphus cooling of a single atom in a localized hollow-beam trap

    International Nuclear Information System (INIS)

    Yin, Yaling; Xia, Yong; Ren, Ruimin; Du, Xiangli; Yin, Jianping

    2015-01-01

    In order to realize a convenient and efficient laser cooling of a single atom, we propose a simple and promising scheme to cool a single neutral atom in a blue-detuned localized hollow-beam trap by intensity-gradient induced Sisyphus cooling, and study the dynamic process of the intensity-gradient cooling of a single 87 Rb atom in the localized hollow-beam trap by using Monte-Carlo simulations. Our study shows that a single 87 Rb atom with a temperature of 120 μK from a magneto-optical trap (MOT) can be directly cooled to a final temperature of 4.64 μK in our proposed scheme. We also investigate the dependences of the cooling results on the laser detuning δ of the localized hollow-beam, the power RP 0 of the re-pumping laser beam, the sizes of both the localized hollow-beam and the re-pumping beam, and find that there is a pair of optimal cooling parameters (δ and RP 0 ) for an expected lowest temperature, and the cooling results strongly depend on the size of the re-pumping beam, but weakly depend on the size of the localized hollow-beam. Finally, we further study the cooling potential of our localized hollow-beam trap for the initial temperature of a single atom, and find that a single 87 Rb atom with an initial temperature of higher than 1 mK can also be cooled directly to about 6.6 μK. (paper)

  16. Cone-Beam CT Localization of Internal Target Volumes for Stereotactic Body Radiotherapy of Lung Lesions

    International Nuclear Information System (INIS)

    Wang Zhiheng; Wu, Q. Jackie; Marks, Lawrence B.; Larrier, Nicole; Yin Fangfang

    2007-01-01

    Purpose: In this study, we investigate a technique of matching internal target volumes (ITVs) in four-dimensional (4D) simulation computed tomography (CT) to the composite target volume in free-breathing on-board cone-beam (CB) CT. The technique is illustrated by using both phantom and patient cases. Methods and Materials: A dynamic phantom with a target ball simulating respiratory motion with various amplitude and cycle times was used to verify localization accuracy. The dynamic phantom was scanned using simulation CT with a phase-based retrospective sorting technique. The ITV was then determined based on 10 sets of sorted images. The size and epicenter of the ITV identified from 4D simulation CT images and the composite target volume identified from on-board CBCT images were compared to assess localization accuracy. Similarly, for two clinical cases of patients with lung cancer, ITVs defined from 4D simulation CT images and CBCT images were compared. Results: For the phantom, localization accuracy between the ITV in 4D simulation CT and the composite target volume in CBCT was within 1 mm, and ITV was within 8.7%. For patient cases, ITVs on simulation CT and CBCT were within 8.0%. Conclusion: This study shows that CBCT is a useful tool to localize ITV for targets affected by respiratory motion. Verification of the ITV from 4D simulation CT using on-board free-breathing CBCT is feasible for the target localization of lung tumors

  17. Possible impact of multi-electron loss events on the average beam charge state in an HIF target chamber and a neutral beam approach

    Science.gov (United States)

    Grisham, L. R.

    2001-05-01

    Experiments were carried out during the early 1980s to assess the obtainable atomic neutralization of energetic beams of negative ions ranging from lithium to silicon. The experiments found (Grisham et al. Rev. Sci. Instrum. 53 (1982) 281; Princeton Plasma Physics Laboratory Report PPPL-1857, 1981) that, for higher atomic number elements than lithium, it appeared that a substantial fraction of the time more than one electron was being lost in a single collision. This result was inferred from the existence of more than one ionization state in the product beam for even the thinnest line densities at which any electron removal took place. Because of accelerator limitations, these experiments were limited to maximum energies of 7 MeV. However, based upon these results, it is possible that multi-electron loss events may also play a significant role in determining the average ion charge state of the much higher Z and more energetic beams traversing the medium in an heavy ion fusion chamber. This could result in the beam charge state being considerably higher than previously anticipated, and might require designers to consider harder vacuum ballistic focusing approaches, or the development of additional space charge neutralization schemes. This paper discusses the measurements that gave rise for these concerns, as well as a description of further measurements that are proposed to be carried out for atomic numbers and energies per amu which would be closer to those required for heavy ion fusion drivers. With a very low current beam of a massive, but low charge state energetic ion, the charge state distribution emerging from a target gas cell could be measured as a function of line density and medium composition. Varying the line density would allow one to simulate the charge state evolution of the beam as a function of distance into the target chamber. This paper also briefly discusses a possible alternative driver approach using photodetachment-neutralized atomic beams

  18. 103PD brachytherapy and external beam irradiation for clinically localized, high-risk prostatic carcinoma

    International Nuclear Information System (INIS)

    Dattoli, Michael; Wallner, Kent; Sorace, Richard; Koval, John; Cash, Jennifer; Acosta, Rudolph; Brown, Charles; Etheridge, James; Binder, Michael; Brunelle, Richard; Kirwan, Novelle; Sanchez, Servando; Stein, Douglas; Wasserman, Stuart

    1996-01-01

    Purpose: To summarize biochemical failure rates and morbidity of external beam irradiation (EBRT) combined with palladium ( 103 Pd) boost for clinically localized high-risk prostate carcinoma. Methods and Materials: Seventy-three consecutive patients with stage T2a-T3 prostatic carcinoma were treated from 1991 through 1994. Each patient had at least one of the following risk factors for extracapsular disease extension: Stage T2b or greater (71 patients), Gleason score 7-10 (40 patients), prostate specific antigen (PSA) >15 (32 patients), or elevated prostatic acid phosphatase (PAP) (17 patients). Patients received 41 Gy EBRT to a limited pelvic field, followed 4 weeks later by a 103 Pd boost (prescription dose: 80 Gy). Biochemical failure was defined as a PSA greater than 1.0 ng/ml (normal 103 Pd brachytherapy for clinically localized, high-risk prostate cancer compare favorably with that reported after conventional dose EBRT alone. Morbidity has been acceptable

  19. (111)Indium-transferrin for localization and quantification of gastrointestinal protein loss

    DEFF Research Database (Denmark)

    Simonsen, Jane Angel; Braad, Poul-Erik; Veje, Annegrete

    2009-01-01

    Objective. To evaluate the indium-111 ((111)In)-transferrin method as a means of localization and quantification of gastrointestinal protein loss. Methods. Fourteen patients and 15 healthy subjects underwent an (111)In-transferrin study consisting of abdominal scintigraphy, whole-body counting...... measurement and determination of plasma activity of (111)In during the course of 5 days. Two of the patients went through a subsequent chromium-51-trichloride test with analysis of radioactivity in faeces in order to compare the results of the two methods. Results. The patients had a mean+/-SEM whole-body...... loss of (111)In of 10.9+/-2.9% for 96 h, while the healthy controls lost 1.8+/-1.3% (p=0.0045). The decay in plasma activity followed biexponential kinetics. The characteristic plasma transit time was 5.0+/-1.0 h in patients and 12.1+/-1.5 h in controls (p=0.0007). Scintigraphically, patients had...

  20. Screening conditions in a magnetized plasma with electron beam, with application to ripple trapped electron losses

    Energy Technology Data Exchange (ETDEWEB)

    Faudot, E.; Heuraux, S. [Nancy-1 Univ. Henri Poincare, LPMIA, UMR CNRS 7040, 54 (France); Colas, L.; Saint-Laurent, F.; Martin, G.; Basiuk, V. [Association Euratom-CEA Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee

    2004-07-01

    In Tore Supra, electrons are accelerated by lower hybrid waves in the direction parallel to the confinement magnetic field, in order to drive non-inductive current. But electrons have also on increase of their perpendicular velocity, then 10% of the most energetic electrons get trapped in the magnetic ripple between 2 adjacent toroidal coils, thus forming a beam. The electron beam follows a banana trajectory, the 20 mm wide protection represented by a cooled copper tube is assumed to protect the VP entrance from this energetic flux. Nevertheless, this beam is able to go beyond the copper tube and creates a hot spot on the steel panel edge able to melt the metal. Heat fluxes deposition on the vertical port (VP) can be understood with a beam+sheath theory including the fact that the sheaths can be obstructed when their length becomes greater than flux tube length. By this way, we identify 4 deposition regimes: 2 free sheath regimes and 2 obstructed sheath regimes. Beam flux deposits either at the entrance of the VP along first 2 cm behind the copper tube or until the end of the VP when beam flux is high and for free sheath. Obstructed sheaths make the repulsive, potential for electrons decrease and so accelerate the flux deposition. (authors)

  1. Treatment of local recurrent breast cancer by divided dose electron beam radiation twice a week

    International Nuclear Information System (INIS)

    Ito, Ichiro; Suzuki, Yoshihiko; Miyaishi, Kazuo; Mitsuhashi, Norio; Kimura, Makoto

    1978-01-01

    The objectives of this study were to investigate the effects of divided dose electron beam radiation twice a week (with a focal dose of 600 rads at a time) on local recurrent tumors of postoperative breast cancer and to compare it with the conventional photon radiation in the hope that it might be better tolerated by the patients, with less damage to normal skin and lung tissues. Out of 261 patients with breast cancer who came to the Department of Radiology, at Gunma Univ. Hospital, Maebashi, during the period Jan., 1970, through Jun., 1976, 41 patients who received electron beam radiation for local recurrence (in 81 sites) and 31 who received prophylactic radiation over the chest wall postoperatively. Tumors completely disappeared from 73 out of 81 sites irradiated for local recurrence (accounting 90% of the 81 sites). The local recurrent lesions were classified to the ''disseminated'' and the ''focal'' type to compare the effects of the radiation, and it was found that the radiation eliminated the tumors from all (100%) of the 63 sites of the former type, while the radiation was capable of eliminating the tumors from only 10 out of the 18 sites of the latter type (56%). When the focal type tumors were classified by histopathologic typing to compare the effects of the radiation, the radiation was assessed effective in papillotubular carcinoma, medullary tubular carcinoma and scirrhous carcinoma in the decreasing sequence of significance. Pulmonary disorders occurred in 12% of all the observed sites. However, it is possible to further reduce this incidence by the adequate use of the tissue compensating filter, Mix-R. A skin disorder (erosion) was observed in 59% of all the sites observed. However, it may be anticipated that the topical application of a suitable corticoid (Beta-methasone-17-valerate cream) preparation will by prophylactically effective. (auth.)

  2. Rehabilitation of molar-incisor hypomineralization (MIH) complicated with localized tooth surface loss: a case report.

    Science.gov (United States)

    Lam, Walter Y H; Ho, Edward H T; Pow, Edmond H N

    2014-05-01

    Molar-incisor hypomineralization (MIH) is a developmental enamel hypomineralized condition characteristically involving the first permanent molars and sometimes also the incisors. The affected teeth are predisposed to tooth surface loss (TSL) which may not only compromise the esthetics and function but also endanger the pulp and longevity of the teeth. This report describes the management of a patient with MIH complicated with localized TSL and lack of occlusal clearance due to dentoalveolar compensation. The atypical TSL pattern involved all anterior teeth and required the placement of Dahl appliances on both arches.

  3. In situ radiation test of silicon and diamond detectors operating in superfluid helium and developed for beam loss monitoring

    Science.gov (United States)

    Kurfürst, C.; Dehning, B.; Sapinski, M.; Bartosik, M. R.; Eisel, T.; Fabjan, C.; Rementeria, C. A.; Griesmayer, E.; Eremin, V.; Verbitskaya, E.; Zabrodskii, A.; Fadeeva, N.; Tuboltsev, Y.; Eremin, I.; Egorov, N.; Härkönen, J.; Luukka, P.; Tuominen, E.

    2015-05-01

    As a result of the foreseen increase in the luminosity of the Large Hadron Collider, the discrimination between the collision products and possible magnet quench-provoking beam losses of the primary proton beams is becoming more critical for safe accelerator operation. We report the results of ongoing research efforts targeting the upgrading of the monitoring system by exploiting Beam Loss Monitor detectors based on semiconductors located as close as possible to the superconducting coils of the triplet magnets. In practice, this means that the detectors will have to be immersed in superfluid helium inside the cold mass and operate at 1.9 K. Additionally, the monitoring system is expected to survive 20 years of LHC operation, resulting in an estimated radiation fluence of 1×1016 proton/cm2, which corresponds to a dose of about 2 MGy. In this study, we monitored the signal degradation during the in situ irradiation when silicon and single-crystal diamond detectors were situated in the liquid/superfluid helium and the dependences of the collected charge on fluence and bias voltage were obtained. It is shown that diamond and silicon detectors can operate at 1.9 K after 1×1016 p/cm2 irradiation required for application as BLMs, while the rate of the signal degradation was larger in silicon detectors than in the diamond ones. For Si detectors this rate was controlled mainly by the operational mode, being larger at forward bias voltage.

  4. An FPGA Based Implementation for Real-Time Processing of the LHC Beam Loss Monitoring System's Data

    CERN Document Server

    Dehning, B; Emery, J; Ferioli, G; Zamantzas, C

    2006-01-01

    The strategy for machine protection and quench prevention of the Large Hadron Collider (LHC) at the European Organisation for Nuclear Research (CERN) is mainly based on the Beam Loss Monitoring (BLM) system. At each turn, there will be several thousands of data to record and process in order to decide if the beams should be permitted to continue circulating or their safe extraction is necessary to be triggered. The processing involves a proper analysis of the loss pattern in time and for the decision the energy of the beam needs to be accounted. This complexity needs to be minimized by all means to maximize the reliability of the BLM system and allow a feasible implementation. In this paper, a field programmable gate array (FPGA) based implementation is explored for the real-time processing of the LHC BLM data. It gives emphasis on the highly efficient Successive Running Sums (SRS) technique used that allows many and long integration periods to be maintained for each detector's data with relatively small leng...

  5. Serum testosterone levels after external beam radiation for clinically localized prostate cancer

    International Nuclear Information System (INIS)

    Zagars, Gunar K.; Pollack, Alan

    1997-01-01

    Purpose: To determine whether serum total testosterone levels change after external beam radiation therapy for localized prostate cancer. Methods and Materials: Eighty-five men with clinically localized prostate cancer (T1-T3, N0/NX, M0) who underwent external beam radiation therapy without androgen ablation had pretreatment and 3-month posttreatment total serum testosterone levels determined by radioimmunoassay. Scattered doses to the testicles were measured with thermoluminescent dosimetry in 10 men. Results: Pretreatment serum testosterone levels ranged from 185 to 783 ng/dl, with a mean of 400 ng/dl and a median of 390 ng/dl. The coefficient of variation was 30%. Postradiation 3-month testosterone levels ranged from 163 ng/dl to 796 ng/dl, with mean and median values of 356 ng/dl and 327 ng/ml, respectively. The coefficient of variation was 34%. The 3-month value was significantly lower than the pretreatment value (Wilcoxon paired p = 0.0001). The mean absolute fall was 94 ng/dl and the mean percentage fall was 9%. Although the fall in testosterone level was statistically significant, the difference was very small quantitatively. In contrast, serum prostate-specific antigen levels fell dramatically by 3 months after radiation. Testicular scattered doses ranged from 1.84 to 2.42 Gy, with a mean of 2.07 Gy for a prostatic tumor dose of 68 Gy. Conclusions: Although significant, the fall in serum testosterone level after radiation for localized prostate cancer was small and likely of no pathophysiologic consequence. It is unlikely that scattered testicular radiation plays any significant role in the genesis of this change in testosterone level, which most likely occurs as a nonspecific stress response

  6. High dose rate interstitial brachytherapy with external beam irradiation for localized prostate cancer. Preliminary results

    Energy Technology Data Exchange (ETDEWEB)

    Hiratsuka, Junichi; Jo, Yoshimasa; Yoden, Eisaku; Tanaka, Hiroyoshi; Imajo, Yoshinari [Kawasaki Medical School, Kurashiki, Okayama (Japan); Nagase, Naomi; Narihiro, Naomasa; Kubota, Juichi

    2000-12-01

    This study was undertaken to assess the biochemical and pathological results of combined external beam radiotherapy and high dose rate Ir-192 brachytherapy (HDR-Ir192) for clinically localized prostate cancer. Between October 1997 and August 1999, 39 evaluable patients with adenocarcinoma of prostate diagnosed by biopsy were treated with interstitial and external beam irradiation. Patients ranged in age from 58-82 years, with a mean of 69.7 years. T1c, T2 and T3 tumors, according to the UICC classification system (1997), were found in 7, 21 and 11 cases respectively. The mean initial pre-treatment PSA was 35.9 ng/ml (median 13.2), with 77% of the patients having had a pre-treatment PSA greater than 10 ng/ml. Of all patients, 17 had received pre-treatment hormonal therapy. Hormonal pretreatment was stopped at the beginning of radiotherapy in all cases. External beam four-field box irradiation was given to the small pelvis to a dose of 45 Gy/25 fractions. Three HDR-Ir192 treatments were given over a 30-h period, with 5.5 Gy per fraction at the circumference of the prostate gland over the course of this study. Biochemical failure was defined as a PSA level >1.5 ng/ml and rising on three consecutive values. If serial post-treatment PSA levels showed a continuous downward trend, failure was not scored. The patient with clinical evidence of progression was classified as a clinical failure. The median follow-up at the time of evaluation was 19.6 months. A post-treatment PSA level {<=}1.0 ng/ml was seen in 26 (67%) patients, and values from >1.0 to {<=}2.0 ng/ml were seen in 10 (26%) patients. Biochemical failure was not seen in 38 patients except for one patient who developed a distant bone metastasis with negative prostatic biopsy 15 months after treatment. Biochemical control rate was 100% (38/38) except for the patient with bone metastasis classified as clinical failure. Negative biopsies 18 months after treatment were found in 93% (14/15) of patients. Only one patient

  7. Characterization of a wide dynamic-range, radiation-tolerant charge-digitizer asic for monitoring of Beam losses

    CERN Document Server

    Guido Venturini, G G; Dehning, B; Kayal, M

    2012-01-01

    An Application Specific Integrated Circuit (ASIC) has been designed and fabricated to provide a compact solution to digitize current signals from ionization chambers and diamond detectors, employed as beam loss monitors at CERN and several other high energy physics facilities. The circuit topology has been devised to accept positive and negative currents, to have a wide dynamic range (above 120 dB), withstand radiation levels over 10 Mrad and offer different modes of operation, covering a broad range of applications. Furthermore, an internal conversion reference is employed in the digitization, to provide an accurate absolute measurement. This paper discusses the detailed characterization of the first prototype: linearity, radiation tolerance and temperature dependence of the conversion, as well as implications and system-level considerations regarding its use for beam instrumentation applications in a high energy physics facility.

  8. Short-term weight loss attenuates local tissue inflammation and improves insulin sensitivity without affecting adipose inflammation in obese mice.

    Science.gov (United States)

    Jung, Dae Young; Ko, Hwi Jin; Lichtman, Eben I; Lee, Eunjung; Lawton, Elizabeth; Ong, Helena; Yu, Kristine; Azuma, Yoshihiro; Friedline, Randall H; Lee, Ki Won; Kim, Jason K

    2013-05-01

    Obesity is a major cause of insulin resistance, and weight loss is shown to improve glucose homeostasis. But the underlying mechanism and the role of inflammation remain unclear. Male C57BL/6 mice were fed a high-fat diet (HFD) for 12 wk. After HFD, weight loss was induced by changing to a low-fat diet (LFD) or exercise with continuous HFD. The weight loss effects on energy balance and insulin sensitivity were determined using metabolic cages and hyperinsulinemic euglycemic clamps in awake mice. Diet and exercise intervention for 3 wk caused a modest weight loss and improved glucose homeostasis. Weight loss dramatically reduced local inflammation in skeletal muscle, liver, and heart but not in adipose tissue. Exercise-mediated weight loss increased muscle glucose metabolism without affecting Akt phosphorylation or lipid levels. LFD-mediated weight loss reduced lipid levels and improved insulin sensitivity selectively in liver. Both weight loss interventions improved cardiac glucose metabolism. These results demonstrate that a short-term weight loss with exercise or diet intervention attenuates obesity-induced local inflammation and selectively improves insulin sensitivity in skeletal muscle and liver. Our findings suggest that local factors, not adipose tissue inflammation, are involved in the beneficial effects of weight loss on glucose homeostasis.

  9. Beam loss reduction by injection painting in the 3-GeV rapid cycling synchrotron of the Japan Proton Accelerator Research Complex

    Directory of Open Access Journals (Sweden)

    H. Hotchi

    2012-04-01

    Full Text Available The 3-GeV rapid cycling synchrotron (RCS of the Japan Proton Accelerator Research Complex was commissioned in October 2007. Via the initial beam tuning and a series of underlying beam studies with low-intensity beams, since December 2009, we have intermittently been performing beam tuning experiments with higher-intensity beams including the injection painting technique. By optimizing the injection painting parameters, we have successfully achieved a 420 kW-equivalent output intensity at a low-level intensity loss of less than 1%. Also the corresponding numerical simulation well reproduced the observed painting parameter dependence on the beam loss, and captured a characteristic behavior of the high-intensity beam in the injection painting process. In this paper, we present the experimental results obtained in the course of the RCS beam power ramp-up, especially on the beam loss reduction achieved by employing the injection painting, together with the numerical simulation results.

  10. Prediction of local loss coefficient for turbulent flow in axisymmetric sudden expansions with a chamfer: Effect of Reynolds number

    International Nuclear Information System (INIS)

    Bae, Youngmin; Kim, Young In

    2014-01-01

    Highlights: • Turbulent flow in axisymmetric sudden expansion with a chamfer is studied numerically. • Reynolds number dependency of the local loss coefficient is investigated. • Extended correlation is proposed for estimation of the local loss coefficient. - Abstract: This paper reports the pressure losses in turbulent flows through axisymmetric sudden expansions having a slight chamfer on the edge. A parametric study is performed for dimensionless chamfer lengths of 0–0.5, expansion ratios of 2–6, and chamfer angles of 0–45° in a Reynolds number range of 1 × 10 5 –8 × 10 5 . The chamfer effect on the expansion losses and its dependence on the Reynolds number are analyzed in detail along with a discussion of the relevant flow features. On the basis of numerical results, an existing correlation of the local loss coefficient is also extended to take into account the effect of the Reynolds number additionally

  11. Neural, Endocrine and Local Mechanisms in the Effects of Environmental Stressors on the Cardiovascular Response to Blood Loss

    National Research Council Canada - National Science Library

    Schadt, James C

    2006-01-01

    Our studies have provided important, new information about the role of neurohumoral systems as well as the interaction of these systems with local mechanisms in cardiovascular control during blood loss...

  12. Neutral Beam Source and Target Plasma for Development of a Local Electric Field Fluctuation Diagnostic

    Science.gov (United States)

    Bakken, M. R.; Burke, M. G.; Fonck, R. J.; Lewicki, B. T.; Rhodes, A. T.; Winz, G. R.

    2016-10-01

    A new diagnostic measuring local E-> (r , t) fluctuations is being developed for plasma turbulence studies in tokamaks. This is accomplished by measuring fluctuations in the separation of the π components in the Hα motional Stark spectrum. Fluctuations in this separation are expected to be Ẽ / ẼEMSE 10-3EMSE 10-3 . In addition to a high throughput, high speed spectrometer, the project requires a low divergence (Ω 0 .5°) , 80 keV, 2.5 A H0 beam and a target plasma test stand. The beam employs a washer-stack arc ion source to achieve a high species fraction at full energy. Laboratory tests of the ion source demonstrate repeatable plasmas with Te 10 eV and ne 1.6 ×1017 m-3, sufficient for the beam ion optics requirements. Te and ne scalings of the ion source plasma are presented with respect to operational parameters. A novel three-phase resonant converter power supply will provide 6 mA/cm2 of 80 keV H0 at the focal plane for pulse lengths up to 15 ms, with low ripple δV / 80 keV 0.05 % at 280 kHz. Diagnostic development and validation tests will be performed on a magnetized plasma test stand with 0.5 T field. The test chamber will utilize a washer-stack arc source to produce a target plasma comparable to edge tokamak plasmas. A bias-plate with programmable power supply will be used to impose Ẽ within the target plasma. Work supported by US DOE Grant DE-FG02-89ER53296.

  13. Locally advanced prostatic cancer: experience with combined pelvic external beam irradiation and interstitial thermobrachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Hancock, Steven L; Kapp, Daniel S; Goffinet, Don R; Prionas, Stavros; Cox, Richard S; Bagshaw, Malcolm A

    1995-07-01

    Purpose: Recurrence of prostatic carcinoma within the prostate gland remains a significant problem for patients who present with locally advanced disease. In an attempt to improve the local control of such tumors, an iridium-192 transperineal, template-guided prostatic implant was combined wit radiofrequency-induced hyperthermia after external beam irradiation of the pelvic lymph nodes and prostate gland. This study evaluates the influence of pre-treatment patient characteristics and treatment parameters upon outcome. Materials and Methods: Between July 1987 and April 1992 33 patients with adenocarcinoma of the prostate were selected for treatment: 28 of these patients had extensive local disease on clinical examination (AJCC-4 stages T2b or c: 9 patients; T3: 19 patients); two patients with T2a tumors had Gleason grade 5 + 4 disease or disproportionately high prostate specific antigen (PSA) values and a mass encroaching upon the bladder on computerized tomographic scan. Three patients with more clinically limited T2a or T2b involvement elected implantation in lieu of an external beam irradiation boost. The mean pre-treatment serum PSA value was 25.6 ng/ml (Hybritech scale), with values of above 19 ng/ml for 17 of the patients. Treatment consisted of 50 Gy of external beam irradiation to the prostate and pelvic lymph nodes followed by a transperineal needle implant of the prostate gland. Thirty-two patients had no evidence of pelvic nodal involvement during exploration at laparotomy performed after external irradiation, and 25 of these had lymph node samplings that were histologically negative for metastasis. Perineal template oriented needles were placed by inspection and palpation at laparotomy; 2 were performed closed under ultrasound guidance. Needles were afterloaded with {sup 192}Ir to provide a dose of 30 Gy to the periphery of the prostate gland. Interstitial radiofrequency-induced hyperthermia treatments were given in conjunction with the implant, one just

  14. Cone-beam local reconstruction based on a Radon inversion transformation

    International Nuclear Information System (INIS)

    Wang Xian-Chao; Yan Bin; Li Lei; Hu Guo-En

    2012-01-01

    The local reconstruction from truncated projection data is one area of interest in image reconstruction for computed tomography (CT), which creates the possibility for dose reduction. In this paper, a filtered-backprojection (FBP) algorithm based on the Radon inversion transform is presented to deal with the three-dimensional (3D) local reconstruction in the circular geometry. The algorithm achieves the data filtering in two steps. The first step is the derivative of projections, which acts locally on the data and can thus be carried out accurately even in the presence of data truncation. The second step is the nonlocal Hilbert filtering. The numerical simulations and the real data reconstructions have been conducted to validate the new reconstruction algorithm. Compared with the approximate truncation resistant algorithm for computed tomography (ATRACT), not only it has a comparable ability to restrain truncation artifacts, but also its reconstruction efficiency is improved. It is about twice as fast as that of the ATRACT. Therefore, this work provides a simple and efficient approach for the approximate reconstruction from truncated projections in the circular cone-beam CT

  15. Loss of locality in gravitational correlators with a large number of insertions

    Science.gov (United States)

    Ghosh, Sudip; Raju, Suvrat

    2017-09-01

    We review lessons from the AdS/CFT correspondence that indicate that the emergence of locality in quantum gravity is contingent upon considering observables with a small number of insertions. Correlation functions, where the number of insertions scales with a power of the central charge of the CFT, are sensitive to nonlocal effects in the bulk theory, which arise from a combination of the effects of the bulk Gauss law and a breakdown of perturbation theory. To examine whether a similar effect occurs in flat space, we consider the scattering of massless particles in the bosonic string and the superstring in the limit, where the number of external particles, n, becomes very large. We use estimates of the volume of the Weil-Petersson moduli space of punctured Riemann surfaces to argue that string amplitudes grow factorially in this limit. We verify this factorial behavior through an extensive numerical analysis of string amplitudes at large n. Our numerical calculations rely on the observation that, in the large n limit, the string scattering amplitude localizes on the Gross-Mende saddle points, even though individual particle energies are small. This factorial growth implies the breakdown of string perturbation theory for n ˜(M/plE ) d -2 in d dimensions, where E is the typical individual particle energy. We explore the implications of this breakdown for the black hole information paradox. We show that the loss of locality suggested by this breakdown is precisely sufficient to resolve the cloning and strong subadditivity paradoxes.

  16. Neighbor Discovery Algorithm in Wireless Local Area Networks Using Multi-beam Directional Antennas

    Science.gov (United States)

    Wang, Jin; Peng, Wei; Liu, Song

    2017-10-01

    Neighbor discovery is an important step for Wireless Local Area Networks (WLAN) and the use of multi-beam directional antennas can greatly improve the network performance. However, most neighbor discovery algorithms in WLAN, based on multi-beam directional antennas, can only work effectively in synchronous system but not in asynchro-nous system. And collisions at AP remain a bottleneck for neighbor discovery. In this paper, we propose two asynchrono-us neighbor discovery algorithms: asynchronous hierarchical scanning (AHS) and asynchronous directional scanning (ADS) algorithm. Both of them are based on three-way handshaking mechanism. AHS and ADS reduce collisions at AP to have a good performance in a hierarchical way and directional way respectively. In the end, the performance of the AHS and ADS are tested on OMNeT++. Moreover, it is analyzed that different application scenarios and the factors how to affect the performance of these algorithms. The simulation results show that AHS is suitable for the densely populated scenes around AP while ADS is suitable for that most of the neighborhood nodes are far from AP.

  17. Bremsstrahlung spectra from thick-target electron beams with noncollisional energy losses

    International Nuclear Information System (INIS)

    Brown, J.C.; MacKinnon, A.L.

    1985-01-01

    We consider what can be learned from the bremsstrahlung radiation of fast electrons in a thick target, generalized to include electron energy losses additional to collisions. We show that the observed photon spectrum can, in principle, be inverted to yield an integral functional of the electron spectrum and the effective energy loss rate. In the light of this result, there seems no reason to suppose, in the absence of a priori information to the contrary, that the photon spectrum is symptomatic more of the fast electron distribution than of the energy loss processes. In cases where the electron injection spectrum is known on independent observational or theoretical grounds, it is possible to infer an effective, ''phenomenological'' energy loss function. In the more general case, however, fullest possible modeling of the physical situation and comparison of the resulting spectrum with observations is all that can be attempted

  18. Local in-depth analysis of ceramic materials by neutral beam secondary ion mass spectrometry

    International Nuclear Information System (INIS)

    Borchardt, G.; Scherrer, H.; Weber, S.; Scherrer, S.

    1980-01-01

    Local microanalysis of non-conducting surfaces by means of modern physical methods which use charged low-energy primary particles brings about severe problems because of the electrostatic charge accumulated on the sample surface. This is also true of secondary ion mass spectrometry (SIMS) where ions are usually used as primary particles. In the present work the basic features for production of neutral primary beams in commercial SIMS instruments by a simple technique are described. With suitably high sputtering rates, surface analyses and in-depth profiles can be made in reasonable measuring times. Results are given for chemical concentration distributions in the near-surface regions of an oxide glass and for the isotopic diffusion of Si-30 in a crystalline silicate with olivine structure (Co 2 SiO 4 ). (orig.)

  19. Luminosities and mass-loss rates of Local Group AGB stars and red supergiants

    Science.gov (United States)

    Groenewegen, M. A. T.; Sloan, G. C.

    2018-01-01

    Context. Mass loss is one of the fundamental properties of asymptotic giant branch (AGB) stars, and through the enrichment of the interstellar medium, AGB stars are key players in the life cycle of dust and gas in the universe. However, a quantitative understanding of the mass-loss process is still largely lacking. Aims: We aim to investigate mass loss and luminosity in a large sample of evolved stars in several Local Group galaxies with a variety of metalliticies and star-formation histories: the Small and Large Magellanic Cloud, and the Fornax, Carina, and Sculptor dwarf spheroidal galaxies (dSphs). Methods: Dust radiative transfer models are presented for 225 carbon stars and 171 oxygen-rich evolved stars in several Local Group galaxies for which spectra from the Infrared Spectrograph on Spitzer are available. The spectra are complemented with available optical and infrared photometry to construct spectral energy distributions. A minimization procedure was used to determine luminosity and mass-loss rate (MLR). Pulsation periods were derived for a large fraction of the sample based on a re-analysis of existing data. Results: New deep K-band photometry from the VMC survey and multi-epoch data from IRAC (at 4.5 μm) and AllWISE and NEOWISE have allowed us to derive pulsation periods longer than 1000 days for some of the most heavily obscured and reddened objects. We derive (dust) MLRs and luminosities for the entire sample. The estimated MLRs can differ significantly from estimates for the same objects in the literature due to differences in adopted optical constants (up to factors of several) and details in the radiative transfer modelling. Updated parameters for the super-AGB candidate MSX SMC 055 (IRAS 00483-7347) are presented. Its current mass is estimated to be 8.5 ± 1.6 M⊙, suggesting an initial mass well above 8 M⊙ in agreement with estimates based on its large Rubidium abundance. Using synthetic photometry, we present and discuss colour-colour and

  20. Implementation status of the global and local beam position feedback systems for the Advanced Photon Source storage ring

    International Nuclear Information System (INIS)

    Chung, Y.; Barr, D.; Decker, G.; Galayda, J.; Kirchman, J.; Lenkszus, F.; Lumpkin, A.; Votaw, A.J.

    1995-01-01

    The Advanced Photon Source (APS) is implementing an extensive beam position feedback system for both global and local stabilization of particle and photon beams based on digital signal processing. The description and operational experience of the system will be given in this paper. In particular, we will discuss the underlying fundamental principles, hardware layout, controls interface, and automatic software generation for multiple digital signal processors (DSPS) distributed in 20 VME crates around the ring. The feedback system runs at 4-kHz sampling frequency in order to achieve the correction bandwidth of approximately 100 Hz. For the maximum correction efficiency and resolution of conflicts among multiple local feedback systems due to the local bump closure error, the global and local feedback systems are combined into a single unified system. This novel approach is made possible through data sharing among the global and local systems via the fiber-optically networked reflective memories

  1. Simple method for calculation of heat loss through floor/beam-wall intersections according to ISO 9164

    International Nuclear Information System (INIS)

    Dilmac, Sukran; Guner, Abdurrahman; Senkal, Filiz; Kartal, Semiha

    2007-01-01

    The international standards for calculation of energy consumption for heating are ISO 9164 and EN 832. Although they are based on similar principles, there are significant differences in the calculation procedure of transmission heat loss coefficient, H T , especially in the evaluation of thermal bridges. The calculation of H T and the way thermal bridges are to be taken into consideration are explained in detail in EN 832 and in a series of other linked standards. In ISO 9164, the parameters used in the relevant equations are cited, but there is a lack of explanation about how they will be determined or calculated. Although in ISO 6946-2, the earlier version of the same standard, the calculation methods of these quantities were explained for column-wall intersections; in the revised ISO 6946, these explanations have been removed. On the other hand, these parameters had never been defined for floor/beam-wall intersections. In this paper, a new method is proposed for calculation of the parameters cited in ISO 9164 for floor/beam-wall intersections. The results obtained by the proposed method for typical floor with beam sections are compared with the results obtained by the methods stated in EN 832/EN 13789/EN ISO 14683 and the results obtained from 2D analysis. Different methods are evaluated as to their simplicity and agreement

  2. In situ radiation test of silicon and diamond detectors operating in superfluid helium and developed for beam loss monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Kurfürst, C.; Dehning, B.; Sapinski, M.; Bartosik, M.R.; Eisel, T.; Fabjan, C.; Rementeria, C.A. [CERN, Geneva (Switzerland); Griesmayer, E. [CIVIDEC Instrumentation, GmbH, Vienna (Austria); Eremin, V. [Ioffe Institute, St. Petersburg (Russian Federation); Verbitskaya, E., E-mail: elena.verbitskaya@cern.ch [Ioffe Institute, St. Petersburg (Russian Federation); Zabrodskii, A.; Fadeeva, N.; Tuboltsev, Y.; Eremin, I. [Ioffe Institute, St. Petersburg (Russian Federation); Egorov, N. [Research Institute of Material Science and Technology, Zelenograd, Moscow (Russian Federation); Härkönen, J.; Luukka, P.; Tuominen, E. [Helsinki Institute of Physics, Helsinki (Finland)

    2015-05-11

    As a result of the foreseen increase in the luminosity of the Large Hadron Collider, the discrimination between the collision products and possible magnet quench-provoking beam losses of the primary proton beams is becoming more critical for safe accelerator operation. We report the results of ongoing research efforts targeting the upgrading of the monitoring system by exploiting Beam Loss Monitor detectors based on semiconductors located as close as possible to the superconducting coils of the triplet magnets. In practice, this means that the detectors will have to be immersed in superfluid helium inside the cold mass and operate at 1.9 K. Additionally, the monitoring system is expected to survive 20 years of LHC operation, resulting in an estimated radiation fluence of 1×10{sup 16} proton/cm{sup 2}, which corresponds to a dose of about 2 MGy. In this study, we monitored the signal degradation during the in situ irradiation when silicon and single-crystal diamond detectors were situated in the liquid/superfluid helium and the dependences of the collected charge on fluence and bias voltage were obtained. It is shown that diamond and silicon detectors can operate at 1.9 K after 1×10{sup 16} p/cm{sup 2} irradiation required for application as BLMs, while the rate of the signal degradation was larger in silicon detectors than in the diamond ones. For Si detectors this rate was controlled mainly by the operational mode, being larger at forward bias voltage. - Highlights: • Silicon and diamond detectors are proposed for beam loss monitoring at LHC. • The first in situ radiation test of Si and diamond detectors at 1.9 K is described. • Both diamond and silicon detectors survived after 1×10{sup 16} p/cm{sup 2} irradiation at 1.9 K. • The rate of Si detectors degradation depends on bias polarity and is larger at V{sub forw}. • Sensitivity of Si detectors irradiated to 1×10{sup 16} p/cm{sup 2} is independent on resistivity.

  3. Challenges of arbitrary waveform signal detection by Silicon Photomultipliers as readout for Cherenkov fibre based beam loss monitoring systems

    CERN Document Server

    Vinogradov, Sergey; Nebot del Busto, Eduardo; Kastriotou, Maria; Welsch, Carsten P

    2016-01-01

    Silicon Photomultipliers (SiPMs) are well recognised as very competitive photodetectors due to their exceptional photon number and time resolution, room-temperature low-voltage operation, insensitivity to magnetic fields, compactness, and robustness. Detection of weak light pulses of nanosecond time scale appears to be the best area for SiPM applications because in this case most of the SiPM drawbacks have a rather limited effect on its performance. In contrast to the more typical scintillation and Cherenkov detection applications, which demand information on the number of photons and/or the arrival time of the light pulse only, beam loss monitoring (BLM) systems utilising Cherenkov fibres with photodetector readout have to precisely reconstruct the temporal profile of the light pulse. This is a rather challenging task for any photon detector especially taking into account the high dynamic range of incident signals (100K – 1M) from a few photons to a few percents of destructive losses in a beam line and pre...

  4. Evolution of beam losses after a power cut of the SR7 AC supply

    CERN Document Server

    GOMEZ ALONSO, A

    2009-01-01

    Magnet failures in the LHC could lead to equipment damage if the energy stored in the accelerator was not discharged properly. The Machine Protection Systems (MPS) ensure this proper discharge and knowledge about the evolution of losses in case of failure is needed to evaluate the adequacy of the protection. A power cut of the AC supply in SR7 would lead to a simultaneous current decay in three normal conducting circuits. The evolution of the losses after such failure is slow, with a loss time constant of more than 100 ms both at 450 GeV and 7 TeV, and in both cases the damage level is not reached before 45 ms. This leaves sufficient time for the MPS to ensure redundant protection. A similar scenario would be expected for a power cut at SR3.

  5. Three-dimensional localization of impacted canines and root resorption assessment using cone beam computed tomography.

    Science.gov (United States)

    Almuhtaseb, Eyad; Mao, Jing; Mahony, Derek; Bader, Rawan; Zhang, Zhi-xing

    2014-06-01

    The purpose of this study was to develop a new way to localize the impacted canines from three dimensions and to investigate the root resorption of the adjacent teeth by using cone beam computed tomography (CBCT). Forty-six patients undergoing orthodontic treatments and having impacted canines in Tongji Hospital were examined. The images of CBCT scans were obtained from KaVo 3D exam vision. Angular and linear measurements of the cusp tip and root apex according to the three planes (mid-sagittal, occlusal and frontal) have been taken using the cephalometric tool of the InVivo Dental Anatomage Version 5.1.10. The measurements of the angular and linear coordinates of the maxillary and mandibular canines were obtained. Using this technique the operators could envision the location of the impacted canine according to the three clinical planes. Adjacent teeth root resorption of 28.26 % was in the upper lateral incisors while 17.39% in upper central incisors, but no lower root resorption was found in our samples. Accurate and reliable localization of the impacted canines could be obtained from the novel analysis system, which offers a better surgical and orthodontic treatment for the patients with impacted canines.

  6. Current reversals and metastable states in the infinite Bose-Hubbard chain with local particle loss

    Science.gov (United States)

    Kiefer-Emmanouilidis, M.; Sirker, J.

    2017-12-01

    We present an algorithm which combines the quantum trajectory approach to open quantum systems with a density-matrix renormalization-group scheme for infinite one-dimensional lattice systems. We apply this method to investigate the long-time dynamics in the Bose-Hubbard model with local particle loss starting from a Mott-insulating initial state with one boson per site. While the short-time dynamics can be described even quantitatively by an equation of motion (EOM) approach at the mean-field level, many-body interactions lead to unexpected effects at intermediate and long times: local particle currents far away from the dissipative site start to reverse direction ultimately leading to a metastable state with a total particle current pointing away from the lossy site. An alternative EOM approach based on an effective fermion model shows that the reversal of currents can be understood qualitatively by the creation of holon-doublon pairs at the edge of the region of reduced particle density. The doublons are then able to escape while the holes move towards the dissipative site, a process reminiscent—in a loose sense—of Hawking radiation.

  7. A Bench Measurement of the Energy Loss of a Stored Beam to a Cavity

    Energy Technology Data Exchange (ETDEWEB)

    Sands, M; Rees, J.; /SLAC

    2016-12-19

    A rather simple electronic bench experiment is proposed for obtaining a measure of the impulse energy loss of a stored particle bunch to an rf cavity or other vacuum-chamber structure--the so-called "cavity radiation". The proposed method is analyzed in some detail.

  8. The toroidicity-induced Alfven eigenmode structure in DIII-D: Implications of soft x-ray and beam-ion loss data

    International Nuclear Information System (INIS)

    Carolipio, E. M.; Heidbrink, W. W.; Cheng, C. Z.; Chu, M. S.; Fu, G. Y.; Jaun, A.; Spong, D. A.; Turnbull, A. D.; White, R. B.

    2001-01-01

    The internal structure of the toroidicity-induced Alfven eigenmode (TAE) is studied by comparing soft x-ray profile and beam ion loss data taken during TAE activity in the DIII-D tokamak [W. W. Heidbrink , Nucl. Fusion 37, 1411 (1997)] with predictions from theories based on ideal magnetohydrodynamic (MHD), gyrofluid, and gyrokinetic models. The soft x-ray measurements indicate a centrally peaked eigenfunction, a feature which is closest to the gyrokinetic model's prediction. The beam ion losses are simulated using a guiding center code. In the simulations, the TAE eigenfunction calculated using the ideal MHD model acts as a perturbation to the equilibrium field. The predicted beam ion losses are an order of magnitude less than the observed ∼6%--8% losses at the peak experimental amplitude of {delta}B r /B 0 ≅2--5 x 10 -4

  9. Optical eye tracking system for real-time noninvasive tumor localization in external beam radiotherapy.

    Science.gov (United States)

    Via, Riccardo; Fassi, Aurora; Fattori, Giovanni; Fontana, Giulia; Pella, Andrea; Tagaste, Barbara; Riboldi, Marco; Ciocca, Mario; Orecchia, Roberto; Baroni, Guido

    2015-05-01

    External beam radiotherapy currently represents an important therapeutic strategy for the treatment of intraocular tumors. Accurate target localization and efficient compensation of involuntary eye movements are crucial to avoid deviations in dose distribution with respect to the treatment plan. This paper describes an eye tracking system (ETS) based on noninvasive infrared video imaging. The system was designed for capturing the tridimensional (3D) ocular motion and provides an on-line estimation of intraocular lesions position based on a priori knowledge coming from volumetric imaging. Eye tracking is performed by localizing cornea and pupil centers on stereo images captured by two calibrated video cameras, exploiting eye reflections produced by infrared illumination. Additionally, torsional eye movements are detected by template matching in the iris region of eye images. This information allows estimating the 3D position and orientation of the eye by means of an eye local reference system. By combining ETS measurements with volumetric imaging for treatment planning [computed tomography (CT) and magnetic resonance (MR)], one is able to map the position of the lesion to be treated in local eye coordinates, thus enabling real-time tumor referencing during treatment setup and irradiation. Experimental tests on an eye phantom and seven healthy subjects were performed to assess ETS tracking accuracy. Measurements on phantom showed an overall median accuracy within 0.16 mm and 0.40° for translations and rotations, respectively. Torsional movements were affected by 0.28° median uncertainty. On healthy subjects, the gaze direction error ranged between 0.19° and 0.82° at a median working distance of 29 cm. The median processing time of the eye tracking algorithm was 18.60 ms, thus allowing eye monitoring up to 50 Hz. A noninvasive ETS prototype was designed to perform real-time target localization and eye movement monitoring during ocular radiotherapy treatments. The

  10. Optical eye tracking system for real-time noninvasive tumor localization in external beam radiotherapy

    International Nuclear Information System (INIS)

    Via, Riccardo; Fassi, Aurora; Fattori, Giovanni; Fontana, Giulia; Pella, Andrea; Tagaste, Barbara; Ciocca, Mario; Riboldi, Marco; Baroni, Guido; Orecchia, Roberto

    2015-01-01

    Purpose: External beam radiotherapy currently represents an important therapeutic strategy for the treatment of intraocular tumors. Accurate target localization and efficient compensation of involuntary eye movements are crucial to avoid deviations in dose distribution with respect to the treatment plan. This paper describes an eye tracking system (ETS) based on noninvasive infrared video imaging. The system was designed for capturing the tridimensional (3D) ocular motion and provides an on-line estimation of intraocular lesions position based on a priori knowledge coming from volumetric imaging. Methods: Eye tracking is performed by localizing cornea and pupil centers on stereo images captured by two calibrated video cameras, exploiting eye reflections produced by infrared illumination. Additionally, torsional eye movements are detected by template matching in the iris region of eye images. This information allows estimating the 3D position and orientation of the eye by means of an eye local reference system. By combining ETS measurements with volumetric imaging for treatment planning [computed tomography (CT) and magnetic resonance (MR)], one is able to map the position of the lesion to be treated in local eye coordinates, thus enabling real-time tumor referencing during treatment setup and irradiation. Experimental tests on an eye phantom and seven healthy subjects were performed to assess ETS tracking accuracy. Results: Measurements on phantom showed an overall median accuracy within 0.16 mm and 0.40° for translations and rotations, respectively. Torsional movements were affected by 0.28° median uncertainty. On healthy subjects, the gaze direction error ranged between 0.19° and 0.82° at a median working distance of 29 cm. The median processing time of the eye tracking algorithm was 18.60 ms, thus allowing eye monitoring up to 50 Hz. Conclusions: A noninvasive ETS prototype was designed to perform real-time target localization and eye movement monitoring

  11. A local region of interest image reconstruction via filtered backprojection for fan-beam differential phase-contrast computed tomography

    International Nuclear Information System (INIS)

    Qi Zhihua; Chen Guanghong

    2007-01-01

    Recently, x-ray differential phase contrast computed tomography (DPC-CT) has been experimentally implemented using a conventional source combined with several gratings. Images were reconstructed using a parallel-beam reconstruction formula. However, parallel-beam reconstruction formulae are not directly applicable for a large image object where the parallel-beam approximation fails. In this note, we present a new image reconstruction formula for fan-beam DPC-CT. There are two major features in this algorithm: (1) it enables the reconstruction of a local region of interest (ROI) using data acquired from an angular interval shorter than 180 0 + fan angle and (2) it still preserves the filtered backprojection structure. Numerical simulations have been conducted to validate the image reconstruction algorithm. (note)

  12. Electronic energy loss of low velocity H+ beams in Al, Ag, Sb, Au and Bi

    International Nuclear Information System (INIS)

    Valdes, J.E.; Martinez Tamayo, G.; Lantschner, G.H.; Eckardt, J.C.; Arista, N.R.

    1993-01-01

    The energy loss of H + ions in thin polycrystalline Al, Sb, Ag, Au and Bi films has been determined in the energy range below 10 keV. This low-energy range is of special interest to fill a lack of low-energy experimental data and test various theoretical predictions and semiempirical formulas. We find that the general theoretical prediction of a velocity-proportional dependence of energy loss does not hold for all targets studied in this work. The velocity-proportionality is better satisfied for Al, Sb and Bi, whereas a departure from such dependence is observed at lower energies for Ag and Au targets. The results obtained here are in good general agreement with nonlinear stopping power calculations based on density functional theory. Comparison with semiempirical predictions, and other experimental results are also done. (orig.)

  13. Application of the extreme value theory to beam loss estimates in the SPIRAL2 linac based on large scale Monte Carlo computations

    Directory of Open Access Journals (Sweden)

    R. Duperrier

    2006-04-01

    Full Text Available The influence of random perturbations of high intensity accelerator elements on the beam losses is considered. This paper presents the error sensitivity study which has been performed for the SPIRAL2 linac in order to define the tolerances for the construction. The proposed driver aims to accelerate a 5 mA deuteron beam up to 20   A MeV and a 1 mA ion beam for q/A=1/3 up to 14.5 A MeV. It is a continuous wave regime linac, designed for a maximum efficiency in the transmission of intense beams and a tunable energy. It consists in an injector (two   ECRs   sources+LEBTs with the possibility to inject from several sources+radio frequency quadrupole followed by a superconducting section based on an array of independently phased cavities where the transverse focalization is performed with warm quadrupoles. The correction scheme and the expected losses are described. The extreme value theory is used to estimate the expected beam losses. The described method couples large scale computations to obtain probability distribution functions. The bootstrap technique is used to provide confidence intervals associated to the beam loss predictions. With such a method, it is possible to measure the risk to loose a few watts in this high power linac (up to 200 kW.

  14. Investigation of Electron Beam Induced Mass Loss of Embedding Media in the Low Voltage STEM

    Czech Academy of Sciences Publication Activity Database

    Novotná, V.; Hrubanová, Kamila; Nebesářová, J.; Krzyžánek, Vladislav

    2014-01-01

    Roč. 20, S3 (2014), s. 1270-1271 ISSN 1431-9276 R&D Projects: GA MŠk EE.2.3.20.0103; GA MŠk(CZ) LO1212; GA ČR(CZ) GA14-20012S; GA TA ČR TE01020118 Institutional support: RVO:68081731 Keywords : mass loss * mass -thickness measurement * low voltage STEM Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.877, year: 2014

  15. Time-resolved cathodoluminescence microscopy with sub-nanosecond beam blanking for direct evaluation of the local density of states

    NARCIS (Netherlands)

    Moerland, R.J.; Weppelman, I.G.C.; Garming, M.W.H.; Kruit, P.; Hoogenboom, J.P.

    2016-01-01

    We show cathodoluminescence-based time-resolved electron beam spectroscopy in order to directly probe the spontaneous emission decay rate that is modified by the local density of states in a nanoscale environment. In contrast to dedicated laser-triggered electron-microscopy setups, we use commercial

  16. Variation in Adherence to External Beam Radiotherapy Quality Measures Among Elderly Men With Localized Prostate Cancer

    International Nuclear Information System (INIS)

    Bekelman, Justin E.; Zelefsky, Michael J.; Jang, Thomas L.; Basch, Ethan M.; Schrag, Deborah

    2007-01-01

    Purpose: To characterize the variation in adherence to quality measures of external beam radiotherapy (EBRT) for localized prostate cancer and its relation to patient and provider characteristics in a population-based, representative sample of U.S. men. Methods and Materials: We evaluated EBRT quality measures proposed by a RAND expert panel of physicians among men aged ≥65 years diagnosed between 2000 and 2002 with localized prostate cancer and treated with primary EBRT using data from the linked Surveillance, Epidemiology, and End Results (SEER)-Medicare program. We assessed the adherence to five EBRT quality measures that were amenable to analysis using SEER-Medicare data: (1) use of conformal RT planning; (2) use of high-energy (>10-MV) photons; (3) use of custom immobilization; (4) completion of two follow-up visits with a radiation oncologist in the year after therapy; and (5) radiation oncologist board certification. Results: Of the 11,674 patients, 85% had received conformal RT planning, 75% had received high-energy photons, and 97% had received custom immobilization. One-third of patients had completed two follow-up visits with a radiation oncologist, although 91% had at least one visit with a urologist or radiation oncologist. Most patients (85%) had been treated by a board-certified radiation oncologist. Conclusions: The overall high adherence to EBRT quality measures masked substantial variation in geography, socioeconomic status in the area of residence, and teaching affiliation of the RT facility. Future research should examine the reasons for the variations in these measures and whether the variation is associated with important clinical outcomes

  17. Hormonal changes after localized prostate cancer treatment. Comparison between external beam radiation therapy and radical prostatectomy.

    Science.gov (United States)

    Planas, J; Celma, A; Placer, J; Maldonado, X; Trilla, E; Salvador, C; Lorente, D; Regis, L; Cuadras, M; Carles, J; Morote, J

    2016-11-01

    To determine the influence of radical prostatectomy (RP) and external beam radiation therapy (EBRT) on the hypothalamic pituitary axis of 120 men with clinically localized prostate cancer treated with RP or EBRT exclusively. 120 patients with localized prostate cancer were enrolled. Ninety two patients underwent RP and 28 patients EBRT exclusively. We measured serum levels of luteinizing hormone, follicle stimulating hormone (FSH), total testosterone (T), free testosterone, and estradiol at baseline and at 3 and 12 months after treatment completion. Patients undergoing RP were younger and presented a higher prostate volume (64.3 vs. 71.1 years, p<0.0001 and 55.1 vs. 36.5 g, p<0.0001; respectively). No differences regarding serum hormonal levels were found at baseline. Luteinizing hormone and FSH levels were significantly higher in those patients treated with EBRT at three months (luteinizing hormone 8,54 vs. 4,76 U/l, FSH 22,96 vs. 8,18 U/l, p<0,0001) while T and free testosterone levels were significantly lower (T 360,3 vs. 414,83ng/dl, p 0,039; free testosterone 5,94 vs. 7,5pg/ml, p 0,018). At 12 months FSH levels remained significantly higher in patients treated with EBRT compared to patients treated with RP (21,01 vs. 8,51 U/l, p<0,001) while T levels remained significantly lower (339,89 vs. 402,39ng/dl, p 0,03). Prostate cancer treatment influences the hypothalamic pituitary axis. This influence seems to be more important when patients with prostate cancer are treated with EBRT rather than RP. More studies are needed to elucidate the role that prostate may play as an endocrine organ. Copyright © 2016 AEU. Publicado por Elsevier España, S.L.U. All rights reserved.

  18. The relationship between technical parameters of external beam radiation therapy and complications for localized prostate cancer

    International Nuclear Information System (INIS)

    Kitamura, Kei; Shirato, Hiroki; Suzuki, Keishiro

    2000-01-01

    This study was performed to review retrospectively the clinical course of chronic rectal bleeding as a complication of external beam radiation therapy for localized prostate cancer and to analyze the relationship between technical parameters of radiation therapy and the complications. Seventy-one patients with stages A2, B and C were treated with local-field radiotherapy (total dose 52.5-66 Gy, daily dose 2.0-3.28 Gy, field area 30-81 cm 2 , number of fields 3-15 ports, planning simulations X-ray or CT-based) between 1989 and 1998 at three institutions. The protocols were consistent during this same period at these institutions. Multivariate analysis revealed pretreatment PSA and Gleason sum to be statistically significant predictors of 5 year prostatic specific antigen (PSA) relapse-free rates in a median follow-up period of 42 months (range 12-119 months). The significant risk factors for higher grading of acute morbidity were a biological equivalent dose, α/β=10 (BED 10 ) ≥65 Gy, dose per fraction ≥3.0 Gy, field area ≥42 cm 2 , fewer ports and X-ray planning simulation. However, no parameter was associated with higher grading of late morbidity. Eleven patients (15.4%) experienced a late GI complication: grade 1 (4.2%), grade 2 (9.8%), grade 3 (1.4%). The median time to occurrence of rectal bleeding was 12 months after radiotherapy and the mean duration of morbidity was 11 months. Higher total dose and dose per fraction, larger field area, fewer ports and X-ray simulation increased the grades of acute morbidity. A majority of chronic rectal bleedings were transient and responded to conservative treatment. (author)

  19. Retrograde amnesia produced by electron beam exposure: casual parameters and duration of memory loss. Final report for November 84

    Energy Technology Data Exchange (ETDEWEB)

    Wheeler, T.G.; Hardy, K.A.

    1985-01-01

    The production of retrograde amnesia (RA) upon electron-beam exposure was investigated. RA production was evaluated using a single-trial avoidance task for 10, 1, and 0.1 microsecond pulsed exposures. The dose-response curve obtained at each pulse duration showed significant RA production. The most effective dose range was 0.1-10 rad at a dose rate of 1,000,000 rad/sec. By employing a 10 rad (1,000,000 rad/s) pulse, a memory loss of the events occurring in the previous 4 sec was demonstrated. The conclusion was that the RA effect might be due to sensory system activation which provided a novel stimulus that masked previous stimuli.

  20. Hypofractionated Proton Boost Combined with External Beam Radiotherapy for Treatment of Localized Prostate Cancer

    Directory of Open Access Journals (Sweden)

    Silvia Johansson

    2012-01-01

    Full Text Available Proton boost of 20 Gy in daily 5 Gy fractions followed by external beam radiotherapy (EBRT of 50 Gy in daily 2 Gy fractions were given to 278 patients with prostate cancer with T1b to T4N0M0 disease. Fifty-three percent of the patients received neoadjuvant androgen deprivation therapy (N-ADT. The medium followup was 57 months. The 5-year PSA progression-free survival was 100%, 95%, and 74% for low-, intermediate-, and high-risk patients, respectively. The toxicity evaluation was supported by a patient-reported questionnaire before every consultant visit. Cumulative probability and actuarial prevalence of genitourinary (GU and gastrointestinal (GI toxicities are presented according to the RTOG classification. N-ADT did not influence curability. Mild pretreatment GU-symptoms were found to be a strong predictive factor for GU-toxicity attributable to treatment. The actuarial prevalence declined over 3 to 5 years for both GU and GI toxicities, indicating slow resolution of epithelial damage to the genitourinary and gastrointestinal tract. Bladder toxicities rather than gastrointestinal toxicities seem to be dose limiting. More than 5-year followup is necessary to reveal any sign of true progressive late side effects of the given treatment. Hypofractionated proton-boost combined with EBRT is associated with excellent curability of localized PC and acceptable frequencies of treatment toxicity.

  1. Raman study of localized recrystallization of amorphous silicon induced by laser beam

    KAUST Repository

    Tabet, Nouar A.

    2012-06-01

    The adoption of amorphous silicon based solar cells has been drastically hindered by the low efficiency of these devices, which is mainly due to a low hole mobility. It has been shown that using both crystallized and amorphous silicon layers in solar cells leads to an enhancement of the device performance. In this study the crystallization of a-Si prepared by PECVD under various growth conditions has been investigated. The growth stresses in the films are determined by measuring the curvature change of the silicon substrate before and after film deposition. Localized crystallization is induced by exposing a-Si films to focused 532 nm laser beam of power ranging from 0.08 to 8 mW. The crystallization process is monitored by recording the Raman spectra after various exposures. The results suggest that growth stresses in the films affect the minimum laser power (threshold power). In addition, a detailed analysis of the width and position of the Raman signal indicates that the silicon grains in the crystallized regions are of few nm diameter. © 2012 IEEE.

  2. Hypofractionated Proton Boost Combined with External Beam Radiotherapy for Treatment of Localized Prostate Cancer

    Science.gov (United States)

    Johansson, Silvia; Åström, Lennart; Sandin, Fredrik; Isacsson, Ulf; Montelius, Anders; Turesson, Ingela

    2012-01-01

    Proton boost of 20 Gy in daily 5 Gy fractions followed by external beam radiotherapy (EBRT) of 50 Gy in daily 2 Gy fractions were given to 278 patients with prostate cancer with T1b to T4N0M0 disease. Fifty-three percent of the patients received neoadjuvant androgen deprivation therapy (N-ADT). The medium followup was 57 months. The 5-year PSA progression-free survival was 100%, 95%, and 74% for low-, intermediate-, and high-risk patients, respectively. The toxicity evaluation was supported by a patient-reported questionnaire before every consultant visit. Cumulative probability and actuarial prevalence of genitourinary (GU) and gastrointestinal (GI) toxicities are presented according to the RTOG classification. N-ADT did not influence curability. Mild pretreatment GU-symptoms were found to be a strong predictive factor for GU-toxicity attributable to treatment. The actuarial prevalence declined over 3 to 5 years for both GU and GI toxicities, indicating slow resolution of epithelial damage to the genitourinary and gastrointestinal tract. Bladder toxicities rather than gastrointestinal toxicities seem to be dose limiting. More than 5-year followup is necessary to reveal any sign of true progressive late side effects of the given treatment. Hypofractionated proton-boost combined with EBRT is associated with excellent curability of localized PC and acceptable frequencies of treatment toxicity. PMID:22848840

  3. Raman study of localized recrystallization of amorphous silicon induced by laser beam

    KAUST Repository

    Tabet, Nouar A.; Al-Sayoud, Abduljabar; Said, Seyed; Yang, Xiaoming; Yang, Yang; Syed, Ahad A.; Diallo, Elhadj; Wang, Zhihong; Wang, Xianbin; Johlin, Eric; Simmons, Christine; Buonassisi, Tonio

    2012-01-01

    The adoption of amorphous silicon based solar cells has been drastically hindered by the low efficiency of these devices, which is mainly due to a low hole mobility. It has been shown that using both crystallized and amorphous silicon layers in solar cells leads to an enhancement of the device performance. In this study the crystallization of a-Si prepared by PECVD under various growth conditions has been investigated. The growth stresses in the films are determined by measuring the curvature change of the silicon substrate before and after film deposition. Localized crystallization is induced by exposing a-Si films to focused 532 nm laser beam of power ranging from 0.08 to 8 mW. The crystallization process is monitored by recording the Raman spectra after various exposures. The results suggest that growth stresses in the films affect the minimum laser power (threshold power). In addition, a detailed analysis of the width and position of the Raman signal indicates that the silicon grains in the crystallized regions are of few nm diameter. © 2012 IEEE.

  4. A simulation of Earthquake Loss Estimation in Southeastern Korea using HAZUS and the local site classification Map

    Science.gov (United States)

    Kang, S.; Kim, K.

    2013-12-01

    Regionally varying seismic hazards can be estimated using an earthquake loss estimation system (e.g. HAZUS-MH). The estimations for actual earthquakes help federal and local authorities develop rapid, effective recovery measures. Estimates for scenario earthquakes help in designing a comprehensive earthquake hazard mitigation plan. Local site characteristics influence the ground motion. Although direct measurements are desirable to construct a site-amplification map, such data are expensive and time consuming to collect. Thus we derived a site classification map of the southern Korean Peninsula using geologic and geomorphologic data, which are readily available for the entire southern Korean Peninsula. Class B sites (mainly rock) are predominant in the area, although localized areas of softer soils are found along major rivers and seashores. The site classification map is compared with independent site classification studies to confirm our site classification map effectively represents the local behavior of site amplification during an earthquake. We then estimated the losses due to a magnitude 6.7 scenario earthquake in Gyeongju, southeastern Korea, with and without the site classification map. Significant differences in loss estimates were observed. The loss without the site classification map decreased without variation with increasing epicentral distance, while the loss with the site classification map varied from region to region, due to both the epicentral distance and local site effects. The major cause of the large loss expected in Gyeongju is the short epicentral distance. Pohang Nam-Gu is located farther from the earthquake source region. Nonetheless, the loss estimates in the remote city are as large as those in Gyeongju and are attributed to the site effect of soft soil found widely in the area.

  5. Beam backgrounds in the ATLAS detector during LHC loss map tests at beta*=40cm and beta*=80cm at Ebeam=6.5 TeV

    CERN Document Server

    The ATLAS collaboration

    2017-01-01

    In this note the beam-background measurements with the ATLAS detector during lossmap tests of the LHC are described. Loss maps taken at beta*=40 cm and the normal 2015 setting of beta*=80 cm are compared. In the first case several collimator settings were explored, resulting in significant changes of beam backgrounds in ATLAS. Besides the studies of the dependence of background on collimation, which are important for optimisation of the LHC performance, these tests provide a clean environment to study the relative importance of beam halo losses on the experiment. The results show that the halo-related component of beam background in ATLAS decreases exponentially with increasing aperture of the tertiary collimators, the slope in terms of nominal sigma being about -0.5. From the data it is also shown that in normal operation conditions of LHC run 2 the beam halo losses contribute at most at the percent level to the total background, the dominant part coming from beam-gas interactions. The data are also used to ...

  6. The two types of a loss of sight (blindness) exhibited by cats and dogs after local irradiation of heat

    International Nuclear Information System (INIS)

    Ushakov, I.B.; Razgovorov, B.L.

    1985-01-01

    After local irradiation of heads with doses of 50 to 100 Gy cats and dogs exhibited two types of a loss of sight: early blindness (during the first two hours) noted only in cats after a dose of 100 Gy, and delayed blindness in cats after a dose of 50 Gy, and in dogs after all doses under study

  7. The Localized Discovery and Recovery for Query Packet Losses in Wireless Sensor Networks with Distributed Detector Clusters

    Directory of Open Access Journals (Sweden)

    Ryu Miura

    2013-06-01

    Full Text Available An essential application of wireless sensor networks is to successfully respond to user queries. Query packet losses occur in the query dissemination due to wireless communication problems such as interference, multipath fading, packet collisions, etc. The losses of query messages at sensor nodes result in the failure of sensor nodes reporting the requested data. Hence, the reliable and successful dissemination of query messages to sensor nodes is a non-trivial problem. The target of this paper is to enable highly successful query delivery to sensor nodes by localized and energy-efficient discovery, and recovery of query losses. We adopt local and collective cooperation among sensor nodes to increase the success rate of distributed discoveries and recoveries. To enable the scalability in the operations of discoveries and recoveries, we employ a distributed name resolution mechanism at each sensor node to allow sensor nodes to self-detect the correlated queries and query losses, and then efficiently locally respond to the query losses. We prove that the collective discovery of query losses has a high impact on the success of query dissemination and reveal that scalability can be achieved by using the proposed approach. We further study the novel features of the cooperation and competition in the collective recovery at PHY and MAC layers, and show that the appropriate number of detectors can achieve optimal successful recovery rate. We evaluate the proposed approach with both mathematical analyses and computer simulations. The proposed approach enables a high rate of successful delivery of query messages and it results in short route lengths to recover from query losses. The proposed approach is scalable and operates in a fully distributed manner.

  8. Results of external beam irradiation for rectal carcinomas locally recurrent after local excision or electrocoagulation; Short communication

    Energy Technology Data Exchange (ETDEWEB)

    Shun Wong, C.; Cummings, B.J.; Keane, T.J.; O' Sullivan, Brian; Catton, C.N. (Princess Margaret Hospital, Toronto, ON (Canada))

    1991-10-01

    The outcome of 42 patients who developed locally recurrent rectal carcinoma after initial local excision or electrocoagulation was presented. Five patients received combined surgery and radiotherapy (XRT). The remaining 37 patients were managed by XRT alone. The overall 5 years actuarial survival and local control rates were 21 and 22 percent, respectively. For patients who received XRT alone, the 5 year actuarial survival and local control rates were 20 and 15 percent, resp. The corresponding figures were 35 and 40 percent for patients who received a total XRT dose of 50 Gy or more. One patient who underwent combined treatment developed rectal and bladder incontinence requiring surgery. For patients with rectal recurrence after initial conservative surgery, XRT is an alternative to abdominoperipheral resection if major resection is contraindicated. (author). 13 refs.; 2 tabs.

  9. Automatic prostate localization on cone-beam CT scans for high precision image-guided radiotherapy

    International Nuclear Information System (INIS)

    Smitsmans, Monique H.P.; Bois, Josien de; Sonke, Jan-Jakob; Betgen, Anja; Zijp, Lambert J.; Jaffray, David A.; Lebesque, Joos V.; Herk, Marcel van

    2005-01-01

    Purpose: Previously, we developed an automatic three-dimensional gray-value registration (GR) method for fast prostate localization that could be used during online or offline image-guided radiotherapy. The method was tested on conventional computed tomography (CT) scans. In this study, the performance of the algorithm to localize the prostate on cone-beam CT (CBCT) scans acquired on the treatment machine was evaluated. Methods and Materials: Five to 17 CBCT scans of 32 prostate cancer patients (332 scans in total) were used. For 18 patients (190 CBCT scans), the CBCT scans were acquired with a collimated field of view (FOV) (craniocaudal). This procedure improved the image quality considerably. The prostate (i.e., prostate plus seminal vesicles) in each CBCT scan was registered to the prostate in the planning CT scan by automatic 3D gray-value registration (normal GR) starting from a registration on the bony anatomy. When these failed, registrations were repeated with a fixed rotation point locked at the prostate apex (fixed apex GR). Registrations were visually assessed in 3D by one observer with the help of an expansion (by 3.6 mm) of the delineated prostate contours of the planning CT scan. The percentage of successfully registered cases was determined from the combined normal and fixed apex GR assessment results. The error in gray-value registration for both registration methods was determined from the position of one clearly defined calcification in the prostate gland (9 patients, 71 successful registrations). Results: The percentage of successfully registered CBCT scans that were acquired with a collimated FOV was about 10% higher than for CBCT scans that were acquired with an uncollimated FOV. For CBCT scans that were acquired with a collimated FOV, the percentage of successfully registered cases improved from 65%, when only normal GR was applied, to 83% when the results of normal and fixed apex GR were combined. Gray-value registration mainly failed (or

  10. Evolution of radiation losses and importance of charge exchange between plasma impurities and injection beam neutrals in the W VII-A stellarator

    International Nuclear Information System (INIS)

    Smeulders, P.

    1981-01-01

    In certain discharges during Neutral Injection (N.I.) (84 0 CO-injection) in the 1 = 2, m = 5 WENDELSTEIN VII-A Stellarator impurity accumulation in the plasma center seems to occur as seen by bolometric, spectroscopic and ultra soft X-ray (USX) measurement. The time evolution of the radiation losses is shown. Three possible sources of the impurities which are responsible for the high central radiation losses are: - Beam injected impurities. - Plasma wall interaction. - Molybdenum protection plates. Possible mechanisms that can be responsible for the central impurity accumulations are: - An inward flow of the plasma or beam impurities. - An increased peaking of the depostion of the beam impurities. Various factors influencing the behaviour of the central radiation are mentioned. (orig./AH)

  11. Complete mechanical behavior analysis of FG Nano Beam under non-uniform loading using non-local theory

    Science.gov (United States)

    Ghaffari, I.; Parhizkar Yaghoobi, M.; Ghannad, M.

    2018-01-01

    The purpose of this study is to offer a complete solution to analyze the mechanical behavior (bending, buckling and vibration) of Nano-beam under non-uniform loading. Furthermore, the effects of size (nonlocal parameters), non-homogeneity constants, and different boundary conditions are investigated by using this method. The exact solution presented here reduces costs incurred by experiments. In this research, the displacement field obeys the kinematics of the Euler-Bernoulli beam theory and non-local elasticity theory has been used. The governing equations and general boundary conditions are derived for a beam by using energy method. The presented solution enables us to analyze any kind of loading profile and boundary conditions with no limitations. Furthermore, this solution, unlike previous studies, is not a series-solution; hence, there is no limitation prior to existing with the series-solution, nor does it need to check convergence. Based on the developed analytical solution, the influence of size, non-homogeneity and non-uniform loads on bending, buckling and vibration behaviors is discussed. Also, the obtained result is highly accurate and in good agreement with previous research. In theoretical method, the allowable range for non-local parameters can be determined so as to make a major contribution to the reduction of the cost of experiments determining the value of non-local parameters.

  12. Monitoring Dosimetric Impact of Weight Loss With Kilovoltage (KV) Cone Beam CT (CBCT) During Parotid-Sparing IMRT and Concurrent Chemotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Ho, Kean Fatt, E-mail: hokeanfatt@hotmail.com [Academic Radiation Oncology, The Christie NHS Foundation Trust, Manchester (United Kingdom); Marchant, Tom; Moore, Chris; Webster, Gareth; Rowbottom, Carl [North Western Medical Physics, The Christie NHS Foundation Trust, Manchester (United Kingdom); Penington, Hazel [Wade Radiotherapy Research Centre, The Christie NHS Foundation Trust, Manchester (United Kingdom); Lee, Lip; Yap, Beng; Sykes, Andrew; Slevin, Nick [Department of Clinical Oncology, The Christie NHS Foundation Trust, Manchester (United Kingdom)

    2012-03-01

    Purpose: Parotid-sparing head-and-neck intensity-modulated radiotherapy (IMRT) can reduce long-term xerostomia. However, patients frequently experience weight loss and tumor shrinkage during treatment. We evaluate the use of kilovoltage (kV) cone beam computed tomography (CBCT) for dose monitoring and examine if the dosimetric impact of such changes on the parotid and critical neural structures warrants replanning during treatment. Methods and materials: Ten patients with locally advanced oropharyngeal cancer were treated with contralateral parotid-sparing IMRT concurrently with platinum-based chemotherapy. Mean doses of 65 Gy and 54 Gy were delivered to clinical target volume (CTV)1 and CTV2, respectively, in 30 daily fractions. CBCT was prospectively acquired weekly. Each CBCT was coregistered with the planned isocenter. The spinal cord, brainstem, parotids, larynx, and oral cavity were outlined on each CBCT. Dose distributions were recalculated on the CBCT after correcting the gray scale to provide accurate Hounsfield calibration, using the original IMRT plan configuration. Results: Planned contralateral parotid mean doses were not significantly different to those delivered during treatment (p > 0.1). Ipsilateral and contralateral parotids showed a mean reduction in volume of 29.7% and 28.4%, respectively. There was no significant difference between planned and delivered maximum dose to the brainstem (p = 0.6) or spinal cord (p = 0.2), mean dose to larynx (p = 0.5) and oral cavity (p = 0.8). End-of-treatment mean weight loss was 7.5 kg (8.8% of baseline weight). Despite a {>=}10% weight loss in 5 patients, there was no significant dosimetric change affecting the contralateral parotid and neural structures. Conclusions: Although patient weight loss and parotid volume shrinkage was observed, overall, there was no significant excess dose to the organs at risk. No replanning was felt necessary for this patient cohort, but a larger patient sample will be investigated

  13. Simulation of equivalent dose due to accidental electron beam loss in Indus-1 and Indus-2 synchrotron radiation sources using FLUKA code

    International Nuclear Information System (INIS)

    Sahani, P.K.; Dev, Vipin; Singh, Gurnam; Haridas, G.; Thakkar, K.K.; Sarkar, P.K.; Sharma, D.N.

    2008-01-01

    Indus-1 and Indus-2 are two Synchrotron radiation sources at Raja Ramanna Centre for Advanced Technology (RRCAT), India. Stored electron energy in Indus-1 and Indus-2 are 450MeV and 2.5GeV respectively. During operation of storage ring, accidental electron beam loss may occur in addition to normal beam losses. The Bremsstrahlung radiation produced due to the beam losses creates a major radiation hazard in these high energy electron accelerators. FLUKA, the Monte Carlo radiation transport code is used to simulate the accidental beam loss. The simulation was carried out to estimate the equivalent dose likely to be received by a trapped person closer to the storage ring. Depth dose profile in water phantom for 450MeV and 2.5GeV electron beam is generated, from which percentage energy absorbed in 30cm water phantom (analogous to human body) is calculated. The simulation showed the percentage energy deposition in the phantom is about 19% for 450MeV electron and 4.3% for 2.5GeV electron. The dose build up factor in 30cm water phantom for 450MeV and 2.5GeV electron beam are found to be 1.85 and 2.94 respectively. Based on the depth dose profile, dose equivalent index of 0.026Sv and 1.08Sv are likely to be received by the trapped person near the storage ring in Indus-1 and Indus-2 respectively. (author)

  14. A numerically research on energy loss evaluation in a centrifugal pump system based on local entropy production method

    Directory of Open Access Journals (Sweden)

    Hou Hucan

    2017-01-01

    Full Text Available Inspired by wide application of the second law of thermodynamics to flow and heat transfer devices, local entropy production analysis method was creatively introduced into energy assessment system of centrifugal water pump. Based on Reynolds stress turbulent model and energy equation model, the steady numerical simulation of the whole flow passage of one IS centrifugal pump was carried out. The local entropy production terms were calculated by user defined functions, mainly including wall entropy production, turbulent entropy production, and viscous entropy production. The numerical results indicated that the irreversible energy loss calculated by the local entropy production method agreed well with that calculated by the traditional method but with some deviations which were probably caused by high rotatability and high curvature of impeller and volute. The wall entropy production and turbulent entropy production took up large part of the whole entropy production about 48.61% and 47.91%, respectively, which indicated that wall friction and turbulent fluctuation were the major factors in affecting irreversible energy loss. Meanwhile, the entropy production rate distribution was discussed and compared with turbulent kinetic energy dissipation rate distribution, it showed that turbulent entropy production rate increased sharply at the near wall regions and both distributed more uniformly. The blade region in leading edge near suction side, trailing edge and volute tongue were the main regions to generate irreversible exergy loss. This research broadens a completely new view in evaluating energy loss and further optimizes pump using entropy production minimization.

  15. The substrate effect in electron energy-loss spectroscopy of localized surface plasmons in gold and silver nanoparticles

    DEFF Research Database (Denmark)

    Kadkhodazadeh, Shima; Christensen, Thomas; Beleggia, Marco

    2017-01-01

    , as in optical measurements, the substrate material can modify the acquired signal. Here, we have investigated how the EELS signal recorded from supported silver and gold spheroidal nanoparticles at different electron beam impact parameter positions is affected by the choice of a dielectric substrate material...... and thickness. Consistent with previous optical studies, the presence of a dielectric substrate is found to redshift localized surface plasmons, increase their line-widths, and lead to increased prominence of higher order modes. The extent of these modifications heightens with increasing substrate permittivity...

  16. Fluorescence detection of white-beam X-ray absorption anisotropy: towards element-sensitive projections of local atomic structure

    International Nuclear Information System (INIS)

    Korecki, P.; Tolkiehn, M.; Dąbrowski, K. M.; Novikov, D. V.

    2011-01-01

    A method for a direct measurement of X-ray projections of the atomic structure is described. Projections of the atomic structure around Nb atoms in a LiNbO 3 single crystal were obtained from a white-beam X-ray absorption anisotropy pattern detected using Nb K fluorescence. Projections of the atomic structure around Nb atoms in a LiNbO 3 single crystal were obtained from a white-beam X-ray absorption anisotropy (XAA) pattern detected using Nb K fluorescence. This kind of anisotropy results from the interference of X-rays inside a sample and, owing to the short coherence length of a white beam, is visible only at small angles around interatomic directions. Consequently, the main features of the recorded XAA corresponded to distorted real-space projections of dense-packed atomic planes and atomic rows. A quantitative analysis of XAA was carried out using a wavelet transform and allowed well resolved projections of Nb atoms to be obtained up to distances of 10 Å. The signal of nearest O atoms was detected indirectly by a comparison with model calculations. The measurement of white-beam XAA using characteristic radiation indicates the possibility of obtaining element-sensitive projections of the local atomic structure in more complex samples

  17. Beam-loss induced pressure rise of Large Hadron Collider collimator materials irradiated with 158 GeV/u $In^{49+}$ ions at the CERN Super Proton Synchrotron

    CERN Document Server

    Mahner, Edgar; Hansen, Jan; Page, Eric; Vincke, H

    2004-01-01

    During heavy ion operation, large pressure rises, up to a few orders of magnitude, were observed at CERN, GSI, and BNL. The dynamic pressure rises were triggered by lost beam ions that impacted onto the vacuum chamber walls and desorbed about 10/sup 4/ to 10/sup 7/ molecules per ion. The deterioration of the dynamic vacuum conditions can enhance charge-exchange beam losses and can lead to beam instabilities or even to beam abortion triggered by vacuum interlocks. Consequently, a dedicated measurement of heavy-ion induced molecular desorption in the GeV/u energy range is important for Large Hadron Collider (LHC) ion operation. In 2003, a desorption experiment was installed at the super proton synchrotron to measure the beam-loss induced pressure rise of potential LHC collimator materials. Samples of bare graphite, sputter coated (Cu, TiZrV) graphite, and 316 LN (low carbon with nitrogen) stainless steel were irradiated under grazing angle with 158 GeV/u indium ions. After a description of the new experimental ...

  18. Beam-Loss Induced Pressure Rise of LHC Collimator Materials Irradiated with 158 GeV/u $In^{49+}$ Ions at the CERN SPS

    CERN Document Server

    Mahner, Edgar; Hansen, Jan; Page, Eric; Vincke, Helmut H

    2004-01-01

    During heavy ion operation, large pressure rises, up to a few orders of magnitude, were observed at CERN, GSI, and BNL. The dynamic pressure rises were triggered by lost beam ions that impacted onto the vacuum chamber walls and desorbed about 1044 to 107 molecules per ion. The deterioration of the dynamic vacuum conditions can enhance charge-exchange beam losses and can lead to beam instabilities or even to beam abortion triggered by vacuum interlocks. Consequently, a dedicated measure-ment of heavy-ion induced molecular desorption in the GeV/u energy range is important for LHC ion operation. In 2003, a desorption experiment was installed at the SPS to measure the beam-loss induced pressure rise of potential LHC collimator materials. Samples of bare graphite, sputter coated (Cu, TiZrV) graphite, and 316 LN stainless steel, were irradiated under grazing angle with 158 GeV/u indium ions. After a description of the new experimental set-up, the results of the pressure rise measurements are presented, and the deri...

  19. Localized Retroprocessing as a Model of Intron Loss in the Plant Mitochondrial Genome.

    Science.gov (United States)

    Cuenca, Argelia; Ross, T Gregory; Graham, Sean W; Barrett, Craig F; Davis, Jerrold I; Seberg, Ole; Petersen, Gitte

    2016-08-03

    Loss of introns in plant mitochondrial genes is commonly explained by retroprocessing. Under this model, an mRNA is reverse transcribed and integrated back into the genome, simultaneously affecting the contents of introns and edited sites. To evaluate the extent to which retroprocessing explains intron loss, we analyzed patterns of intron content and predicted RNA editing for whole mitochondrial genomes of 30 species in the monocot order Alismatales. In this group, we found an unusually high degree of variation in the intron content, even expanding the hitherto known variation among angiosperms. Some species have lost some two-third of the cis-spliced introns. We found a strong correlation between intron content and editing frequency, and detected 27 events in which intron loss is consistent with the presence of nucleotides in an edited state, supporting retroprocessing. However, we also detected seven cases of intron loss not readily being explained by retroprocession. Our analyses are also not consistent with the entire length of a fully processed cDNA copy being integrated into the genome, but instead indicate that retroprocessing usually occurs for only part of the gene. In some cases, several rounds of retroprocessing may explain intron loss in genes completely devoid of introns. A number of taxa retroprocessing seem to be very common and a possibly ongoing process. It affects the entire mitochondrial genome. © The Author 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  20. Digital image correlation analysis of local strain fields on Ti6Al4V manufactured by electron beam melting

    International Nuclear Information System (INIS)

    Karlsson, Joakim; Sjögren, Torsten; Snis, Anders; Engqvist, Håkan; Lausmaa, Jukka

    2014-01-01

    Additive manufacturing, or 3D-printing as it is often called, build parts in a layer-by-layer fashion. A common concern, regardless of the specific additive manufacturing technique used, is the risk of inadequate fusion between the adjacent layers which in turn may cause inferior mechanical properties. In this work, the local strain properties of titanium parts produced by Electron Beam Melting (EBM ® ) were studied in order to gain information about the quality of fusion of the stock powder material used in the process. By using Digital Image Correlation (DIC) the strain fields in the individual layers were analyzed, as well as the global strain behavior of the bulk material. The results show that fully solid titanium parts manufactured by EBM are homogenous and do not experience local deformation behavior, neither on local nor on a global level

  1. Digital image correlation analysis of local strain fields on Ti6Al4V manufactured by electron beam melting

    Energy Technology Data Exchange (ETDEWEB)

    Karlsson, Joakim, E-mail: Joakim.karlsson@sp.se [SP Technical Research Institute of Sweden, Box 857, SE-501 15, Borås (Sweden); Division of Applied Materials Science, Department of Engineering Sciences, Ångström Laboratory, Uppsala University, Box 534, SE-751 21 Uppsala (Sweden); Sjögren, Torsten [SP Technical Research Institute of Sweden, Box 857, SE-501 15, Borås (Sweden); Snis, Anders [Arcam AB, Krokslätts fabriker 27 A, SE-431 37, Mölndal (Sweden); Engqvist, Håkan [Division of Applied Materials Science, Department of Engineering Sciences, Ångström Laboratory, Uppsala University, Box 534, SE-751 21 Uppsala (Sweden); Lausmaa, Jukka [SP Technical Research Institute of Sweden, Box 857, SE-501 15, Borås (Sweden)

    2014-11-17

    Additive manufacturing, or 3D-printing as it is often called, build parts in a layer-by-layer fashion. A common concern, regardless of the specific additive manufacturing technique used, is the risk of inadequate fusion between the adjacent layers which in turn may cause inferior mechanical properties. In this work, the local strain properties of titanium parts produced by Electron Beam Melting (EBM{sup ®}) were studied in order to gain information about the quality of fusion of the stock powder material used in the process. By using Digital Image Correlation (DIC) the strain fields in the individual layers were analyzed, as well as the global strain behavior of the bulk material. The results show that fully solid titanium parts manufactured by EBM are homogenous and do not experience local deformation behavior, neither on local nor on a global level.

  2. Feasibility of contrast-enhanced cone-beam CT for target localization and treatment monitoring

    International Nuclear Information System (INIS)

    Rodal, Jan; Sovik, Aste; Skogmo, Hege Kippenes; Knudtsen, Ingerid Skjei; Malinen, Eirik

    2010-01-01

    A dog with a spontaneous maxillary tumour was given 40 Gy of fractionated radiotherapy. At five out of 10 fractions cone-beam CT (CBCT) imaging before and after administration of an iodinated contrast agent were performed. Contrast enhancement maps were overlaid on the pre-contrast CBCT images. The tumour was clearly visualized in the images thus produced.

  3. Conformal Brachytherapy Boost To External Beam Irradiation For Clinically Localized High Risk Prostate Cancer

    International Nuclear Information System (INIS)

    Dattoli, Michael J.; Wasserman, Stuart G.; Koval, John M.; Sorace, Richard A.; Cash, Jennifer; Wallner, Kent E.

    1995-01-01

    Purpose: To evaluate the efficacy of using a Pd-103 implant as a boost in conjunction with external beam radiotherapy (EBRT) in patients having prostate cancer associated with adverse features. Materials and Methods: 114 consecutive high risk patients have been treated with combination EBRT and Pd-103 implant. 70 patients with follow-up range of 12-42 months (median 24 months) form the basis of this report. Each patient had at least one of the following risk factors for extra-capsular disease extension: Stage T2b or greater ((66(70))), Gleason score ≥ 7 ((38(70))), significantly elevated PSA (typically > 15 ng/ml)((30(70))) or elevated serum prostatic acid phosphatase (SPAP)((17(70))). Patients received median 4140 cGy EBRT to a limited pelvic field followed by a Pd-103 boost (median prescription dose: 8000 cGy). All patients have been followed in a prospective fashion with respect to PSA response, clinical evidence of disease progression and complications. Criteria for biochemical failure was relatively strict, and was analyzed using both, PSA > 2.0 and PSA > 1.0 as end points. Patients whose PSA was still decreasing at last follow-up were censored at that time. Freedom from failure rates were calculated by the method of Kaplan and Meier. Differences between groups were determined by the Log-rank method. Sexual potency was defined as the ability to attain and maintain an erection sufficient for intercourse. Results: Actuarial freedom from biochemical failure at 3 years after treatment was 90% and 78%, when PSA > 2 and PSA > 1 were used, respectively. There are no documented local relapses. 4 patients failed distantly, and all other failures are based solely on rising PSA values. Biochemical failure was higher in patients having Gleason score ≥ 7 (p=0.001), those with PSA >20 (p=0.014) and in those with elevated SPAP (p=0.007). The primary treatment related morbity was temporary, Grade 1-2 urinary symptoms. No patient developed rectal ulceration or prostatic

  4. Conformal Brachytherapy Boost To External Beam Irradiation For Clinically Localized High Risk Prostate Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Dattoli, Michael J; Wasserman, Stuart G; Koval, John M; Sorace, Richard A; Cash, Jennifer; Wallner, Kent E

    1995-07-01

    Purpose: To evaluate the efficacy of using a Pd-103 implant as a boost in conjunction with external beam radiotherapy (EBRT) in patients having prostate cancer associated with adverse features. Materials and Methods: 114 consecutive high risk patients have been treated with combination EBRT and Pd-103 implant. 70 patients with follow-up range of 12-42 months (median 24 months) form the basis of this report. Each patient had at least one of the following risk factors for extra-capsular disease extension: Stage T2b or greater ((66(70))), Gleason score {>=} 7 ((38(70))), significantly elevated PSA (typically > 15 ng/ml)((30(70))) or elevated serum prostatic acid phosphatase (SPAP)((17(70))). Patients received median 4140 cGy EBRT to a limited pelvic field followed by a Pd-103 boost (median prescription dose: 8000 cGy). All patients have been followed in a prospective fashion with respect to PSA response, clinical evidence of disease progression and complications. Criteria for biochemical failure was relatively strict, and was analyzed using both, PSA > 2.0 and PSA > 1.0 as end points. Patients whose PSA was still decreasing at last follow-up were censored at that time. Freedom from failure rates were calculated by the method of Kaplan and Meier. Differences between groups were determined by the Log-rank method. Sexual potency was defined as the ability to attain and maintain an erection sufficient for intercourse. Results: Actuarial freedom from biochemical failure at 3 years after treatment was 90% and 78%, when PSA > 2 and PSA > 1 were used, respectively. There are no documented local relapses. 4 patients failed distantly, and all other failures are based solely on rising PSA values. Biochemical failure was higher in patients having Gleason score {>=} 7 (p=0.001), those with PSA >20 (p=0.014) and in those with elevated SPAP (p=0.007). The primary treatment related morbity was temporary, Grade 1-2 urinary symptoms. No patient developed rectal ulceration or prostatic

  5. Organ localization in fractionated external beam radiotherapy for early stage prostatic adenocarcinoma

    International Nuclear Information System (INIS)

    Jaffray, D.A.; Horwitz, E.M.; Wong, J.W.; Martinez, A.A.; Brabbins, D.S.

    1996-01-01

    Purpose: Trends toward higher target doses and more conformal radiation field shaping place strict requirements on geometric localisation of the target and surrounding normal structures. Daily localization of these structures is not possible on a conventional treatment machine. For this reason, margins must be incorporated in the field shaping to accommodate any target or normal structure displacement. There are few studies which examine the magnitude of these displacements. We hypothesize that these uncertainties can be reduced by daily radiographic imaging of bony anatomy as an alternative to skin tattoos. This hypothesis is tested using multiple (15-19) CT scans on five patients receiving external beam radiotherapy of the prostate. Materials and Methods: Five patients were CT scanned in treatment position (with immobilization device) on every second day of their initial XRT course (non-boost). Radiopaque markers were placed on the skin tattoos to make them visible in the CT datasets. The scans were collected on a helical CT scanner (SR-7000, 3mm and 5mm slice thickness, 120kVp) and transferred to a workstation for analysis. The structures (prostate, rectum, bladder, and seminal vesicles) on all 80 CT datasets were contoured (manually) by two physicians. A reference dataset was chosen for each patient. The 3D transformations between the study datasets and the reference set were determined using an automated technique. A separate transformation was determined for the alignment of (i) bone (excluding femora) and (ii) skin marks. The contours from each dataset were then transformed back to the reference dataset. The resulting contours show the position of organ relative to either the skin marks (tattoos) or the bony anatomy. The displacement and distortion of the organs were parameterized by the displacement of the volume edge (AP, LAT, SUP-INF), volume, and center-of-mass (COM). Each calculation was performed for an individual patient. Population averages were also

  6. Localized excitons in quantum wells show spin relaxation without coherence loss

    DEFF Research Database (Denmark)

    Zimmermann, R.; Langbein, W.; Runge, E.

    2001-01-01

    The coherence in the secondary emission from quantum well excitons is studied using the speckle method. Analysing the different polarization channels allows to conclude that (i) no coherence loss occurs in the cross-polarized emission, favouring spin beating instead of spin dephasing, and that (i...

  7. Intracultural Differences in Local Botanical Knowledge and Knowledge Loss among the Mexican Isthmus Zapotecs.

    Directory of Open Access Journals (Sweden)

    Alfredo Saynes-Vásquez

    Full Text Available This study reports on the socio-demographic and locality factors that influence ethnobiological knowledge in three communities of Zapotec indigenous people of the Isthmus of Tehuantepec, Mexico. It uses local botanical nomenclature as a proxy for general ethnobiological knowledge. In each of these communities (one urban and two rural, 100 adult men were interviewed aided with a field herbarium. Fifty had a background in farming, and 50 worked in the secondary or tertiary sector as their main economic activity, totaling 300 interviews. Using a field herbarium with samples of 30 common and rare wild regional species, we documented visual recognition, knowledge of the local life form, generic and specific names and uses (five knowledge levels measuring knowledge depth. The relationship between sociodemographic variables and knowledge was analyzed with simple correlations. Differences between the three communities and the five knowledge levels were then evaluated with a discriminant analysis. A general linear analysis identified factors and covariables that influenced the observed differences. Differences between the groups with different economic activities were estimated with a t-test for independent samples. Most of the relationships found between sociodemographic variables and plant knowledge were expected: age and rurality were positively related with knowledge and years of formal schooling was negatively related. However, the somewhat less rural site had more traditional knowledge due to local circumstances. The general linear model explained 70-77% of the variation, a high value. It showed that economic activity was by far the most important factor influencing knowledge, by a factor of five. The interaction of locality and economic activity followed. The discriminant analysis assigned interviewees correctly to their localities in 94% of the cases, strengthening the evidence for intracultural variation. Both sociodemographic and historic

  8. The freely localized microwave discharge in air in the focused beam of the electromagnetic energy

    International Nuclear Information System (INIS)

    Alexandrov, A.F.; Kuzovnikov, A.A.; Shibkov, V.M.

    1995-01-01

    The successfull use of the microwave discharge in many applications make it necessary to research the physics of a new kind of discharge - the electrodeless microwave discharge in the focused beam, in the free space and to search for ways to optimize this discharge parameters. The breakdown was performed in a discharge chamber at approximately free space conditions: R/λ much-gt 1, where R = 1 m is the discharge chamber's dimension, λ = 2 divided-by 10 cm is the wavelength of the microwave radiation. The focused electromagnetic beam was formed by a trumped-lens antenna. The electric field E≤6 kV/cm, the density of energy flow S≤10 5 W/cm 2 , the wave is linearity polarized. The microwave pulse duration could be changed from 1 μs to 1 ms. The gas pressure (nitrogen, air) is varied from 1 to 760 torr

  9. A Real-Time FPGA based Algorithm for the combination of Beam Loss Acquisition Methods used for Measurement Dynamic Range expansion

    CERN Document Server

    Kwiatkowski, M; Alsdorf, M; Dehning, B; Vigano, W

    2012-01-01

    The aim of the Beam Loss Monitoring Dual Polarity (BLEDP) module under development at the European Organisation for Nuclear Research (CERN) is to measure and digitise with high precision the current produced by several types of beam loss detectors. The BLEDP module consists of eight analogue channels each with a fully differential integrator and an accompanying 16 bit ADC at the output of each analogue integrator. The on-board FPGA device controls the integral periods, instructs the ADC devices to perform measurements at the end of each period and collects the measurements. In the next stage it combines the number of charge and discharge cycles accounted in the last interval together with the cycle fractions observed using the ADC samples to produce a digitised high precision value of the charges collected. This paper describes briefly the principle of the fully differential integrator and focuses on the algorithm employed to process the digital data.

  10. Recovery effects due to the interaction between nuclear and electronic energy losses in SiC irradiated with a dual-ion beam

    Energy Technology Data Exchange (ETDEWEB)

    Thomé, Lionel, E-mail: thome@csnsm.in2p3.fr; Debelle, Aurélien; Garrido, Frédérico; Sattonnay, Gaël; Mylonas, Stamatis [Centre de Sciences Nucléaires et de Sciences de la Matière, CNRS-IN2P3-Université Paris-Sud, Bât. 108, F-91405 Orsay (France); Velisa, Gihan [CEA, DEN, Service de Recherches de Métallurgie Physique, Laboratoire JANNUS, F-91191 Gif-sur-Yvette (France); Horia Hulubei National Institute for Physics and Nuclear Engineering, P.O.B. MG-6, 077125 Magurele (Romania); Miro, Sandrine; Trocellier, Patrick; Serruys, Yves [CEA, DEN, Service de Recherches de Métallurgie Physique, Laboratoire JANNUS, F-91191 Gif-sur-Yvette (France)

    2015-03-14

    Single and dual-beam ion irradiations of silicon carbide (SiC) were performed to study possible Synergetic effects between Nuclear (S{sub n}) and Electronic (S{sub e}) Energy Losses. Results obtained combining Rutherford backscattering in channeling conditions, Raman spectroscopy, and transmission electron microscopy techniques show that dual-beam irradiation of SiC induces a dramatic change in the final sample microstructure with a substantial decrease of radiation damage as compared to single-beam irradiation. Actually, a defective layer containing dislocations is formed upon dual-beam irradiation (S{sub n} and S{sub e}), whereas single low-energy irradiation (S{sub n} alone) or even sequential (S{sub n} + S{sub e}) irradiations lead to full amorphization. The healing process is ascribed to the electronic excitation arising from the electronic energy loss of swift ions. These results shed new light on the long-standing puzzling problem of the existence of a possible synergy between S{sub n} and S{sub e} in ion-irradiation experiments. This work is interesting for both fundamental understanding of the ion-solid interactions and technological applications in the nuclear industry where recovery S{sub n}/S{sub e} effects may preserve the integrity of nuclear devices.

  11. Fluorescence detection of white-beam X-ray absorption anisotropy: towards element-sensitive projections of local atomic structure

    Science.gov (United States)

    Korecki, P.; Tolkiehn, M.; Dąbrowski, K. M.; Novikov, D. V.

    2011-01-01

    Projections of the atomic structure around Nb atoms in a LiNbO3 single crystal were obtained from a white-beam X-ray absorption anisotropy (XAA) pattern detected using Nb K fluorescence. This kind of anisotropy results from the interference of X-rays inside a sample and, owing to the short coherence length of a white beam, is visible only at small angles around interatomic directions. Consequently, the main features of the recorded XAA corresponded to distorted real-space projections of dense-packed atomic planes and atomic rows. A quantitative analysis of XAA was carried out using a wavelet transform and allowed well resolved projections of Nb atoms to be obtained up to distances of 10 Å. The signal of nearest O atoms was detected indirectly by a comparison with model calculations. The measurement of white-beam XAA using characteristic radiation indicates the possibility of obtaining element-sensitive projections of the local atomic structure in more complex samples. PMID:21997909

  12. Remote sensing of local structure of the quasi-perpendicular Earth's bow shock by using field-aligned beams

    Directory of Open Access Journals (Sweden)

    B. Miao

    2009-03-01

    Full Text Available Field-aligned ion beams (FABs originate at the quasi-perpendicular Earth's bow shock and constitute an important ion population in the foreshock region. The bulk velocity of these FABs depends significantly on the shock normal angle, which is the angle between shock normal and upstream interplanetary magnetic field (IMF. This dependency may therefore be taken as an indicator of the local structure of the shock. Applying the direct reflection model to Cluster measurements, we have developed a method that uses proton FABs in the foreshock region for remote sensing of the local shock structure. The comparison of the model results with the multi-spacecraft observations of FAB events shows very good agreement in terms of wave amplitude and frequency of surface waves at the shock front.

  13. Assessment of local variability by high-throughput e-beam metrology for prediction of patterning defect probabilities

    Science.gov (United States)

    Wang, Fuming; Hunsche, Stefan; Anunciado, Roy; Corradi, Antonio; Tien, Hung Yu; Tang, Peng; Wei, Junwei; Wang, Yongjun; Fang, Wei; Wong, Patrick; van Oosten, Anton; van Ingen Schenau, Koen; Slachter, Bram

    2018-03-01

    We present an experimental study of pattern variability and defectivity, based on a large data set with more than 112 million SEM measurements from an HMI high-throughput e-beam tool. The test case is a 10nm node SRAM via array patterned with a DUV immersion LELE process, where we see a variation in mean size and litho sensitivities between different unique via patterns that leads to a seemingly qualitative differences in defectivity. The large available data volume enables further analysis to reliably distinguish global and local CDU variations, including a breakdown into local systematics and stochastics. A closer inspection of the tail end of the distributions and estimation of defect probabilities concludes that there is a common defect mechanism and defect threshold despite the observed differences of specific pattern characteristics. We expect that the analysis methodology can be applied for defect probability modeling as well as general process qualification in the future.

  14. Beam loss caused by edge focusing of injection bump magnets and its mitigation in the 3-GeV rapid cycling synchrotron of the Japan Proton Accelerator Research Complex

    Directory of Open Access Journals (Sweden)

    H. Hotchi

    2016-01-01

    Full Text Available In the 3-GeV rapid cycling synchrotron of the Japan Proton Accelerator Research Complex, transverse injection painting is utilized not only to suppress space-charge induced beam loss in the low energy region but also to mitigate foil scattering beam loss during charge-exchange injection. The space-charge induced beam loss is well minimized by the combination of modest transverse painting and full longitudinal painting. But, for sufficiently mitigating the foil scattering part of beam loss, the transverse painting area has to be further expanded. However, such a wide-ranging transverse painting had not been realized until recently due to beta function beating caused by edge focusing of pulsed injection bump magnets during injection. This beta function beating additionally excites random betatron resonances through a distortion of the lattice superperiodicity, and its resultant deterioration of the betatron motion stability causes significant extra beam loss when expanding the transverse painting area. To solve this issue, we newly installed pulse-type quadrupole correctors to compensate the beta function beating. This paper presents recent experimental results on this correction scheme for suppressing the extra beam loss, while discussing the beam loss and its mitigation mechanisms with the corresponding numerical simulations.

  15. Localized surface grafting reactions on carbon nanofibers induced by gamma and e-beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Evora, M.C., E-mail: cecilia@ieav.cta.br [Institute for Advanced Studies-IEAV/DCTA, Av. Cel Jose Alberto Albano do Amarante, 1-Putim, 12228-001 São Jose dos Campos, SP (Brazil); Araujo, J.R., E-mail: jraraujo@inmetro.gov.br [Instituto Nacional de Metrologia, Qualidade e Tecnologia, Av. Nossa Sra. das Graças, 50, 25250-020 Duque de Caxias, RJ (Brazil); Ferreira, E.H.M. [Instituto Nacional de Metrologia, Qualidade e Tecnologia, Av. Nossa Sra. das Graças, 50, 25250-020 Duque de Caxias, RJ (Brazil); Strohmeier, B.R. [Thermo Fisher Scientific, 5225 Verona Road, Madison, WI 53711 (United States); Silva, L.G.A., E-mail: lgasilva@ipen.br [Institute for Nuclear and Energy Research- IPEN, Av. Prof lineu Prestes, 2242- Cidade Universitaria, 05508-000 SP (Brazil); Achete, C.A. [Instituto Nacional de Metrologia, Qualidade e Tecnologia, Av. Nossa Sra. das Graças, 50, 25250-020 Duque de Caxias, RJ (Brazil)

    2015-04-30

    Graphical abstract: - Highlights: • Methodology for the functionalization of carbon nanofibers was investigated. • Two radiation sources were used to promote grafting reactions: gamma and electron beam. • We report the optimum inhibitor concentration to achieve the functionalization. • Surface of carbon nanofibers showed an increase of oxygen content after irradiation. • The radiation-induced graphitization did not damage the overall sp{sup 2} structure. - Abstract: Electron beam and gamma-ray irradiation have potential application to modify the carbon fiber nanostructures in order to produce useful defects in the graphitic structure and create reactive sites. In this study, the methodology to functionalize carbon nanofiber (CNF), via a radiation process and using acrylic acid as a source of oxygen functional groups, was investigated. The samples were submitted to a direct grafting radiation process with electron beam and gamma-ray source. Several parameters were changed such as: acrylic acid concentration, radiation dose and percentage of inhibitor necessary to achieve functionalization, with higher percentage of oxygen functional groups on CNF surface, and better dispersion. The better results achieved were when mixing CNF in a solution of acrylic acid with 6% of inhibitor (FeSO{sub 4}·7H{sub 2}O) and irradiated at 100 kGy. The samples were characterized by X-ray photoelectron spectroscopy and the surface composition (atomic%) showed a significant increase of oxygen content for the samples after irradiation. Also, the dispersion of the functionalized CNF in water was stable during months which may be a good indication that the functionalization process of CNF via ionizing radiation was successful.

  16. Localized surface grafting reactions on carbon nanofibers induced by gamma and e-beam irradiation

    International Nuclear Information System (INIS)

    Evora, M.C.; Araujo, J.R.; Ferreira, E.H.M.; Strohmeier, B.R.; Silva, L.G.A.; Achete, C.A.

    2015-01-01

    Graphical abstract: - Highlights: • Methodology for the functionalization of carbon nanofibers was investigated. • Two radiation sources were used to promote grafting reactions: gamma and electron beam. • We report the optimum inhibitor concentration to achieve the functionalization. • Surface of carbon nanofibers showed an increase of oxygen content after irradiation. • The radiation-induced graphitization did not damage the overall sp 2 structure. - Abstract: Electron beam and gamma-ray irradiation have potential application to modify the carbon fiber nanostructures in order to produce useful defects in the graphitic structure and create reactive sites. In this study, the methodology to functionalize carbon nanofiber (CNF), via a radiation process and using acrylic acid as a source of oxygen functional groups, was investigated. The samples were submitted to a direct grafting radiation process with electron beam and gamma-ray source. Several parameters were changed such as: acrylic acid concentration, radiation dose and percentage of inhibitor necessary to achieve functionalization, with higher percentage of oxygen functional groups on CNF surface, and better dispersion. The better results achieved were when mixing CNF in a solution of acrylic acid with 6% of inhibitor (FeSO 4 ·7H 2 O) and irradiated at 100 kGy. The samples were characterized by X-ray photoelectron spectroscopy and the surface composition (atomic%) showed a significant increase of oxygen content for the samples after irradiation. Also, the dispersion of the functionalized CNF in water was stable during months which may be a good indication that the functionalization process of CNF via ionizing radiation was successful

  17. CoCrMo cellular structures made by Electron Beam Melting studied by local tomography and finite element modelling

    Energy Technology Data Exchange (ETDEWEB)

    Petit, Clémence [INSA de Lyon, MATEIS CNRS UMR5510, Université de Lyon, 69621 Villeurbanne (France); Maire, Eric, E-mail: eric.maire@insa-lyon.fr [INSA de Lyon, MATEIS CNRS UMR5510, Université de Lyon, 69621 Villeurbanne (France); Meille, Sylvain; Adrien, Jérôme [INSA de Lyon, MATEIS CNRS UMR5510, Université de Lyon, 69621 Villeurbanne (France); Kurosu, Shingo; Chiba, Akihiko [Institute for Materials Research, Tohoku University, Sendai 980-0812 (Japan)

    2016-06-15

    The work focuses on the structural and mechanical characterization of Co-Cr-Mo cellular samples with cubic pore structure made by Electron Beam Melting (EBM). X-ray tomography was used to characterize the architecture of the sample. High resolution images were also obtained thanks to local tomography in which the specimen is placed close to the X-ray source. These images enabled to observe some defects due to the fabrication process: small pores in the solid phase, partially melted particles attached to the surface. Then, in situ compression tests were performed in the tomograph. The images of the deformed sample show a progressive buckling of the vertical struts leading to final fracture. The deformation initiated where the defects were present in the strut i.e. in regions with reduced local thickness. The finite element modelling confirmed the high stress concentrations of these weak points leading to the fracture of the sample. - Highlights: • CoCrMo samples fabricated by Electron Beam Melting (EBM) process are considered. • X-ray Computed Tomography is used to observe the structure of the sample. • The mechanical properties are tested thanks to an in situ test in the tomograph. • A finite element model is developed to model the mechanical behaviour.

  18. Role of Local Infiltration of Tranexamic Acid in Reducing Blood Loss in Peritrochanteric Fracture Surgery in the Elderly Population

    Directory of Open Access Journals (Sweden)

    Virani SR

    2016-11-01

    Full Text Available Introduction: Peritrochanteric fractures are common injuries occurring in elderly patients. Surgeries for these fractures are associated with significant blood loss. Intravenous tranexamic acid has a proven track record in many orthopaedic surgeries including trauma, arthroplasty and spine surgeries. Objective: To study the effect of local subfascial and intramuscular infiltration of tranexamic acid in reducing blood loss and the requirement for blood transfusion in intertrochanteric fracture surgery. Study Design: Single centre prospective analytical study. Materials and Methods: One hundred and thirty seven patients above 65 years of age were included in the study, divided into two groups: the intervention group received subfascial and intramuscular infiltration of 2g tranexamic acid before wound closure and the control group of alternate patients did not receive any tranexamic acid infiltration. The postoperative drain output was recorded, as well as the haemoglobin level and the patients needing blood transfusion. Results and Conclusions: The preoperative and postoperative haemoglobin values were recorded. The mean preoperative haemoglobin was 10.9% and 10.8% (p=0.79 in the trial and control groups respectively. The mean postoperative haemoglobin was 9.5gm% and 9.2gm% (p=0.36 in the two groups. The total postoperative blood loss in the tranexamic acid group and the control group was 190.3ml and 204.3ml respectively (p=0.25. Ten patients (14.9% in the intervention group and 12 patients (17.1% in the control group required blood transfusion. We conclude that tranexamic acid does not play a significant role in reducing postoperative blood loss and blood transfusion when used locally in peritochanteric fracture surgery. However a larger double blinded study comparing various modalities of use of tranexamic acid is needed to conclusively establish its role.

  19. Influence of external beam technique and brachytherapy quality assurance on the side effects in the combined external beam- and brachytherapy treatment of local advanced prostate cancer

    International Nuclear Information System (INIS)

    Kovacs, G.; Galalae, R.; Wirth, B.; Bertermann, H.; Wilhelm, R.; Kohr, P.; Kimmig, B.

    1996-01-01

    Transrectal ultrasound(TRUS) guided HDR implantation of the prostate has been established at the Kiel University by Bertermann and Brix in 1986 and there are to date 179 (T1b-T3 No Mo) patients treated in a combined modality. The dose for the implant was 2x 15 Gy on the capsule of the prostate in 14-20 days. For local and regional lymph nodes 20 Gy external beam therapy (AP-PA pelvic portals), 20 Gy with an individual transmission block (100% for subclinical disease, 70% and 50% according to the implant dosimetry for the prostate) and 10 Gy small volume irradiation for the prostate was applied, conventional fractioned. Total dose after the therapy 70 Gy for the prostate and 50 Gy for the subclinical disease in 6-7 weeks. As a quality control method we use since 1991 in vivo dosimetry on the medial rectum wall as well as in the prostatic part of the urethra. Regular follow-up 3-118 months after therapy (median 55) with PSA, digital rectal examination, control TRUS with volumetry (after one year with biopsy) and bone scan. There were no major early side effects within the first three months. Proctitis till 1991 with a duration up to 12 months 49%, prolonging more than one year in 23 %, (total proctitis 72.6%). Dysuria in up to 12 months 30 %, long lasting 30% (total number of dysuria 60 %). Erectile dysfunction in 56 %. Because of the number of the side effects 1991 we changed the external beam technique: instead of the biaxial arch therapy the AP-PA portals, and reduced irradiated volume (from 6480 cm 3 to 5040 cm 3 ). We introduced instead of the small volume arch therapy for 10 Gy external boost the box-technique with shielding the back part of the rectum and the upper part of the bladder resulting additional volume reduction. Through the 15 Gy HDR brachytherapy dose on the prostate capsule there are up to 8 Gy on the medial rectal wall, measured by in vivo dosimetry. This dose could not be responsible for the high number of side effects (see gynecological

  20. Results of the studies on energy deposition in IR6 superconducting magnets from continuous beam loss on the TCDQ system

    CERN Document Server

    Bracco, C; Presland, A; Redaelli, S; Sarchiapone, L; Weiler, T

    2007-01-01

    A single sided mobile graphite diluter block TCDQ, in combination with a two-sided secondary collimator TCS and an iron shield TCDQM, will be installed in front of the superconducting quadrupole Q4 magnets in IR6, in order to protect it and other downstream LHC machine elements from destruction in the event of a beam dump that is not synchronised with the abort gap. The TCDQ will be positioned close to the beam, and will intercept the particles from the secondary halo during low beam lifetime. Previous studies (1-4) have shown that the energy deposited in the Q4 magnet coils can be close to or above the quench limit. In this note the results of the latest FLUKA energy deposition simulations for Beam 2 are described, including an upgrade possibility for the TCDQ system with an additional shielding device. The results are discussed in the context of the expected performance levels for the different phases of LHC operation.

  1. Far-field interaction of focused relativistic electron beams in electron energy loss spectroscopy of nanoscopic platelets

    OpenAIRE

    Itskovsky, M. A.; Cohen, H.; Maniv, T.

    2008-01-01

    A quantum mechanical scattering theory for relativistic, highly focused electron beams near nanoscopic platelets is presented, revealing a new excitation mechanism due to the electron wave scattering from the platelet edges. Radiative electromagnetic excitations within the light cone are shown to arise, allowed by the breakdown of momentum conservation along the beam axis in the inelastic scattering process. Calculated for metallic (silver and gold) and insulating (SiO2 and MgO) nanoplatelets...

  2. Production of radioactivity in local soil at AGS fast neutrino beam

    International Nuclear Information System (INIS)

    Gollon, P.J.; Hauptmann, M.G.; McIntyre, K.; Miltenberger, R.; Naidu, J.

    1984-01-01

    Brookhaven National Laboratory (BNL) has recently decided to construct a new neutrino production target station at the Alternating Gradient Synchrotron (AGS). To determine the environmental impact of this addition, a study is being conducted in the vicinity of the old target area to determine the radiological consequences of operating this experimental facility. Typical BNL soil samples were placed at two locations near an operating target: at right angles to the target and behind thick shielding close to the direction of the incident beam. These samples were used to determine radionuclide production and leaching information. A core was taken from beneath the concrete floor of the old target area and a monitoring well was installed down-gradient of the facility. Preliminary results from all areas of the study are presented along with estimates of the potential environmental impact of the old and new facilities. 9 figures

  3. Automatic prostate localization on cone-beam CT scans for high precision image-guided radiotherapy

    NARCIS (Netherlands)

    Smitsmans, Monique H. P.; de Bois, Josien; Sonke, Jan-Jakob; Betgen, Anja; Zijp, Lambert J.; Jaffray, David A.; Lebesque, Joos V.; van Herk, Marcel

    2005-01-01

    PURPOSE: Previously, we developed an automatic three-dimensional gray-value registration (GR) method for fast prostate localization that could be used during online or offline image-guided radiotherapy. The method was tested on conventional computed tomography (CT) scans. In this study, the

  4. Investigation of local losses as a function of material removal in a large-grain superconducting niobium cavity

    International Nuclear Information System (INIS)

    Gianluigi Ciovati; Peter Kneisel

    2006-01-01

    The performance of a superconducting radio-frequency (RF) cavity made of residual resistivity ratio (RRR) > 200 large-grain niobium has been investigated as a function of material removal, between 70 and 240 ?m, by buffered chemical polishing (BCP). Temperature maps of the cavity surface at 1.7 and 2.0 K were taken for each step of chemical etching and revealed localized losses (''hot-spots''), which contribute to the degradation of the cavity quality factor as a function of the RF surface field. It was found that the number of ''hot-spots'' decreased for larger material removal. Interestingly, the losses at the ''hot-spots'' at different locations evolved differently for successive material removal. The cavity achieved peak surface magnetic fields of about of 130 mT and was limited mostly by thermal quench. By measuring the temperature dependence of the surface resistance (Rs) at low field between 4.2 K and 1.7 K, the variation of material parameters such as the energy gap at 0 K, the residual resistance and the mean free path as a function of material removal could also be investigated. This contribution presents the results of the RF tests along with the temperature maps and the analysis of the losses caused by the ''hot-spots''

  5. Impact of the pedestal plasma density on dynamics of edge localized mode crashes and energy loss scaling

    Energy Technology Data Exchange (ETDEWEB)

    Xu, X. Q., E-mail: xxu@llnl.gov [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Ma, J. F. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Institute for Fusion Studies, University of Texas, Austin, Texas 78712 (United States); Li, G. Q. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Institute of Plasma Physics, Chinese Academy of Sciences, Hefei (China)

    2014-12-15

    The latest BOUT++ studies show an emerging understanding of dynamics of edge localized mode (ELM) crashes and the consistent collisionality scaling of ELM energy losses with the world multi-tokamak database. A series of BOUT++ simulations are conducted to investigate the scaling characteristics of the ELM energy losses vs collisionality via a density scan. Linear results demonstrate that as the pedestal collisionality decreases, the growth rate of the peeling-ballooning modes decreases for high n but increases for low n (1 < n < 5), therefore the width of the growth rate spectrum γ(n) becomes narrower and the peak growth shifts to lower n. Nonlinear BOUT++ simulations show a two-stage process of ELM crash evolution of (i) initial bursts of pressure blob and void creation and (ii) inward void propagation. The inward void propagation stirs the top of pedestal plasma and yields an increasing ELM size with decreasing collisionality after a series of micro-bursts. The pedestal plasma density plays a major role in determining the ELM energy loss through its effect on the edge bootstrap current and ion diamagnetic stabilization. The critical trend emerges as a transition (1) linearly from ballooning-dominated states at high collisionality to peeling-dominated states at low collisionality with decreasing density and (2) nonlinearly from turbulence spreading dynamics at high collisionality into avalanche-like dynamics at low collisionality.

  6. Can local application of Tranexamic acid reduce post-coronary bypass surgery blood loss? A randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Latter David

    2009-06-01

    Full Text Available Abstract Background Diffuse microvascular bleeding remains a common problem after cardiac procedures. Systemic use of antifibrinolytic reduces the postoperative blood loss. The purpose of this study was to examine the effectiveness of local application of tranexamic acid to reduce blood loss after coronary artery bypass grafting (CABG. Methods Thirty eight patients scheduled for primary isolated coronary artery bypass grafting were included in this double blind, prospective, randomized, placebo controlled study. Tranexamic acid (TA group (19 patients received 1 gram of TA diluted in 100 ml normal saline. Placebo group (19 patients received 100 ml of normal saline only. The solution was purred in the pericardial and mediastinal cavities. Results Both groups were comparable in their baseline demographic and surgical characteristics. During the first 24 hours post-operatively, cumulative blood loss was significantly less in TA group (median of 626 ml compared to Placebo group (median of 1040 ml (P = 0.04. There was no significant difference in the post-op Packed RBCs transfusion between both groups (median of one unit in each (P = 0.82. Significant less platelets transfusion required in TA group (median zero unit than in placebo group (median 2 units (P = 0.03. Apart from re-exploration for excessive surgical bleeding in one patient in TA group, no difference was found in morbidity or mortality between both groups. Conclusion Topical application of tranexamic acid in patients undergoing primary coronary artery bypass grafting led to a significant reduction in postoperative blood loss without adding extra risk to the patient.

  7. Localization of simulated damage on a steel beam from random vibrations

    Czech Academy of Sciences Publication Activity Database

    Bayer, Jan; Král, J.; Urushadze, Shota

    2018-01-01

    Roč. 62, č. 1 (2018), s. 112-116 ISSN 0553-6626 R&D Projects: GA ČR(CZ) GC17-26353J Institutional support: RVO:68378297 Keywords : damage localization * change of natural modes * flexibility matrix * flexibility curvatures * case study * damage detection * vibration monitoring Subject RIV: JM - Building Engineering OBOR OECD: Construction engineering, Municipal and structural engineering Impact factor: 0.313, year: 2016 https://pp.bme.hu/ci/ article /view/10625

  8. Correlation of beam electron and LED signal losses under irradiation and long-term recovery of lead tungstate crystals

    International Nuclear Information System (INIS)

    Batarin, V.A.; Butler, J.; Davidenko, A.M.; Derevschikov, A.A.; Goncharenko, Y.M.; Grishin, V.N.; Kachanov, V.A.; Konstantinov, A.S.; Kravtsov, V.I.; Kubota, Y.; Lukanin, V.S.; Matulenko, Y.A.; Melnick, Y.M.; Meschanin, A.P.; Mikhalin, N.E.; Minaev, N.G.; Mochalov, V.V.; Morozov, D.A.; Nogach, L.V.; Ryazantsev, A.V.; Semenov, P.A.; Semenov, V.K.; Shestermanov, K.E.; Soloviev, L.F.; Stone, S.; Uzunian, A.V.; Vasiliev, A.N.; Yakutin, A.E.; Yarba, J.

    2005-01-01

    Radiation damage in lead tungstate crystals reduces their transparency. The calibration that relates the amount of light detected in such crystals to incident energy of photons or electrons is of paramount importance to maintaining the energy resolution the detection system. We report on tests of lead tungstate crystals, read out by photomultiplier tubes, exposed to irradiation by monoenergetic electron or pion beams. The beam electrons themselves were used to measure the scintillation light output, and a blue light emitting diode (LED) was used to track variations of crystals transparency. We report on the correlation of the LED measurement with radiation damage by the beams and also show that it can accurately monitor the crystal recovery from such damage

  9. Updated results of high-dose rate brachytherapy and external beam radiotherapy for locally and locally advanced prostate cancer using the RTOG-ASTRO phoenix definition

    Directory of Open Access Journals (Sweden)

    Antonio C. Pellizzon

    2008-06-01

    Full Text Available PURPOSE: To evaluate the prognostic factors for patients with local or locally advanced prostate cancer treated with external beam radiotherapy (RT and high dose rate brachytherapy (HDR according to the RTOG-ASTRO Phoenix Consensus Conference. MATERIALS AND METHODS: The charts of 209 patients treated between 1997 and 2005 with localized RT and HDR as a boost at the Department of Radiation Oncology, AC Camargo Hospital, Sao Paulo, Brazil were reviewed. Clinical and treatment parameters i.e.: patient's age, Gleason score, clinical stage, initial PSA (iPSA, risk group (RG for biochemical failure, doses of RT and HDR were evaluated. Median age and median follow-up time were 68 and 5.3 years, respectively. Median RT and HDR doses were 45 Gy and 20 Gy. RESULTS: Disease specific survival (DSS at 3.3 year was 94.2%. Regarding RG, for the LR (low risk, IR (intermediate risk and HR (high risk, the DSS rates at 3.3 years were 91.5%, 90.2% and 88.5%, respectively. On univariate analysis prognostic factors related to DSS were RG (p = 0.040, Gleason score ≤ 6 ng/mL (p = 0.002, total dose of HDR ≥ 20 Gy (p < 0.001 On multivariate analysis the only statistical significant predictive factor for biochemical control (bNED was the RG, p < 0.001 (CI - 1.147-3.561. CONCLUSIONS: Although the radiation dose administered to the prostate is an important factor related to bNED, this could not be established with statistical significance in this group of patients. To date , in our own experience, HDR associated to RT could be considered a successful approach in the treatment of prostate cancer.

  10. Proton beam radiotherapy as part of comprehensive regional nodal irradiation for locally advanced breast cancer.

    Science.gov (United States)

    Verma, Vivek; Iftekaruddin, Zaid; Badar, Nida; Hartsell, William; Han-Chih Chang, John; Gondi, Vinai; Pankuch, Mark; Gao, Ming; Schmidt, Stacey; Kaplan, Darren; McGee, Lisa

    2017-05-01

    This study evaluates acute toxicity outcomes in breast cancer patients treated with adjuvant proton beam therapy (PBT). From 2011 to 2016, 91 patients (93 cancers) were treated with adjuvant PBT targeting the intact breast/chest wall and comprehensive regional nodes including the axilla, supraclavicular fossa, and internal mammary lymph nodes. Toxicity was recorded weekly during treatment, one month following treatment, and then every 6months according to the Common Terminology Criteria for Adverse Events (CTCAE) v4.0. Charts were retrospectively reviewed to verify toxicities, patient parameters, disease and treatment characteristics, and disease-related outcomes. Median follow-up was 15.5months. Median PBT dose was 50.4 Gray relative biological effectiveness (GyRBE), with subsequent boost as clinically indicated (N=61, median 10 GyRBE). Chemotherapy, when administered, was given adjuvantly (N=42) or neoadjuvantly (N=46). Grades 1, 2, and 3 dermatitis occurred in 23%, 72%, and 5%, respectively. Eight percent required treatment breaks owing to dermatitis. Median time to resolution of dermatitis was 32days. Grades 1, 2, and 3 esophagitis developed in 31%, 33%, and 0%, respectively. PBT displays acceptable toxicity in the setting of comprehensive regional nodal irradiation. Copyright © 2017. Published by Elsevier B.V.

  11. External beam radiotherapy of localized prostatic adenocarcinoma. Evaluation of conformal therapy, field number and target margins

    International Nuclear Information System (INIS)

    Lennernaes, B.; Rikner, G.; Letocha, H.; Nilsson, S.

    1995-01-01

    The purpose of the present study was to identify factors of importance in the planning of external beam radiotherapy of prostatic adenocarcinoma. Seven patients with urogenital cancers were planned for external radiotherapy of the prostate. Four different techniques were used, viz. a 4-field box technique and four-, five- or six-field conformal therapy set-ups combined with three different margins (1-3 cm). The evaluations were based on the doses delivered to the rectum and the urinary bladder. A normal tissue complication probability (NTCP) was calculated for each plan using Lyman's dose volume reduction method. The most important factors that resulted in a decrease of the dose delivered to the rectum and the bladder were the use of conformal therapy and smaller margins. Conformal therapy seemed more important for the dose distribution in the urinary bladder. Five- and six-field set-ups were not significantly better than those with four fields. NTCP calculations were in accordance with the evaluation of the dose volume histograms. To conclude, four-field conformal therapy utilizing reduced margins improves the dose distribution to the rectum and the urinary bladder in the radiotherapy of prostatic adenocarcinoma. (orig.)

  12. Three Different Approaches for Localization in a Corridor Environment by Means of an Ultrasonic Wide Beam

    Directory of Open Access Journals (Sweden)

    Luigi Spedicato

    2013-03-01

    Full Text Available In this paper the authors present three methods to detect the position and orientation of an observer, such as a mobile robot, with respect to a corridor wall. They use an inexpensive sensor to spread a wide ultrasonic beam. The sensor is rotated by means of an accurate servomotor in order to propagate ultrasonic waves towards a regular wall. Whatever the wall material may be the scanning surface appears to be an acoustic reflector as a consequence of low air impedance. The realized device is able to give distance information in each motor position and thus permits the derivation of a set of points as a ray trace-scanner. The dataset contains points lying on a circular arc and relating to strong returns. Three different approaches are herein considered to estimate both the slope of the wall and its minimum distance from the sensor. Slope and perpendicular distance are the parameters of a target plane, which may be calculated in each observer's position to predict its new location. Experimental tests and simulations are shown and discussed by scanning from different stationary locations. They allow the appreciation of the effectiveness of the proposed approaches.

  13. The local distribution of radiation quality of a collimated fast neutron beam from 15 MeV deuterons on beryllium

    International Nuclear Information System (INIS)

    Fidorra, J.; Booz, J.

    1978-01-01

    The local distribution of radiation quality (ysub(F), ysub(D)) of a collimated fast neutron beam from 14 MeV deuterons on Beryllium was studied with a spherical 1/2 inch EG and G proportional counter simulating a diameter of 2μm. The deuterons were accelerated by the compact cyclotron CV-28 of the Kernforschungsanlage Juelich. The collimator was constructed by the Cyclotron Corporation. The mean neutron energy was 6 MeV. The measurements were performed in air and in a water phantom at a target skin distance of 125 cm. The energy deposition spectra of fast neutrons obtained at various positions were separated into three components of different radiation quality: the gamma component, the recoil proton component, and the heavy ion component

  14. Tumor induction in mice after local irradiation with single doses of either carbon-ion beams or gamma rays.

    Science.gov (United States)

    Ando, Koichi; Koike, Sachiko; Ohmachi, Yasushi; Ando, Yutaka; Kobashi, Gen

    2014-12-01

    To determine the dose-dependent relative biological effectiveness (RBE) for tumor prevalence in mice receiving single localized doses to their right leg of either carbon ions (15, 45 or 75 keV/μm) or 137Cs gamma rays. A total of 1647 female C3H mice were irradiated to their hind legs with a localized dose of either reference gamma rays or 15, 45 or 75 keV/μm carbon-ion beams. Irradiated mice were evaluated for tumors twice a month during their three-year life span, and the dimensions of any tumors found were measured with a caliper. The tumor induction frequency was calculated by Kaplan-Meier analysis. The incidence of tumors from 50 Gy of 45 keV/μm carbon ions was marginally higher than those from 50 Gy of gamma rays. However, 60 Gy of 15 keV/μm carbon ions induced significantly fewer tumors than did gamma rays. RBE values of 0.87 + 0.12, 1.29 + 0.08 or 2.06 + 0.39 for lifetime tumorigenesis were calculated for 15, 45 or 75 keV/μm carbon-ion beams, respectively. Fibrosarcoma predominated, with no Linear Energy Transfer (LET)-dependent differences in the tumor histology. Experiments measuring the late effect of leg skin shrinkage suggested that the carcinogenic damage of 15 keV/μm carbon ions would be less than that of gamma rays. We conclude that patients receiving radiation doses to their normal tissues would face less risk of secondary tumor induction by carbon ions of intermediate LET values compared to equivalent doses of photons.

  15. Quality of Life and Toxicity From Passively Scattered and Spot-Scanning Proton Beam Therapy for Localized Prostate Cancer

    International Nuclear Information System (INIS)

    Pugh, Thomas J.; Munsell, Mark F.; Choi, Seungtaek; Nguyen, Quyhn Nhu; Mathai, Benson; Zhu, X. Ron; Sahoo, Narayan; Gillin, Michael; Johnson, Jennifer L.; Amos, Richard A.; Dong, Lei; Mahmood, Usama; Kuban, Deborah A.; Frank, Steven J.; Hoffman, Karen E.; McGuire, Sean E.; Lee, Andrew K.

    2013-01-01

    Purpose: To report quality of life (QOL)/toxicity in men treated with proton beam therapy for localized prostate cancer and to compare outcomes between passively scattered proton therapy (PSPT) and spot-scanning proton therapy (SSPT). Methods and Materials: Men with localized prostate cancer enrolled on a prospective QOL protocol with a minimum of 2 years' follow-up were reviewed. Comparative groups were defined by technique (PSPT vs SSPT). Patients completed Expanded Prostate Cancer Index Composite questionnaires at baseline and every 3-6 months after proton beam therapy. Clinically meaningful differences in QOL were defined as ≥0.5 × baseline standard deviation. The cumulative incidence of modified Radiation Therapy Oncology Group grade ≥2 gastrointestinal (GI) or genitourinary (GU) toxicity and argon plasma coagulation were determined by the Kaplan-Meier method. Results: A total of 226 men received PSPT, and 65 received SSPT. Both PSPT and SSPT resulted in statistically significant changes in sexual, urinary, and bowel Expanded Prostate Cancer Index Composite summary scores. Only bowel summary, function, and bother resulted in clinically meaningful decrements beyond treatment completion. The decrement in bowel QOL persisted through 24-month follow-up. Cumulative grade ≥2 GU and GI toxicity at 24 months were 13.4% and 9.6%, respectively. There was 1 grade 3 GI toxicity (PSPT group) and no other grade ≥3 GI or GU toxicity. Argon plasma coagulation application was infrequent (PSPT 4.4% vs SSPT 1.5%; P=.21). No statistically significant differences were appreciated between PSPT and SSPT regarding toxicity or QOL. Conclusion: Both PSPT and SSPT confer low rates of grade ≥2 GI or GU toxicity, with preservation of meaningful sexual and urinary QOL at 24 months. A modest, yet clinically meaningful, decrement in bowel QOL was seen throughout follow-up. No toxicity or QOL differences between PSPT and SSPT were identified. Long-term comparative results in a

  16. Circumferential bone loss around splinted and nonsplinted immediately loaded implants retaining mandibular overdentures: A randomized controlled clinical trial using cone beam computed tomography.

    Science.gov (United States)

    Elsyad, Moustafa Abdou; Khirallah, Ahmed Samir

    2016-11-01

    Circumferential marginal bone around 2 splinted and nonsplinted immediately loaded implants in the edentulous mandible has not been previously investigated. The purpose of this randomized controlled clinical trial was to assess circumferential bone loss around splinted and nonsplinted immediately loaded implants retaining mandibular overdentures, using cone beam computed tomography (CBCT). Thirty participants with complete edentulism were allocated to 2 groups and received 2 implants in the canine region of the mandible. Implants were either left nonsplinted (with ball attachment [BA]) or splinted (with bar attachment [RA]). Mandibular overdentures were connected to the implants 1 week later. CBCT was used to evaluate vertical bone loss (VBL) and horizontal bone loss (HBLo) bone loss at the distal (D), buccal (B), mesial (M), and lingual (L) sites of each implant upon overdenture insertion (baseline, T0), 1 year (T1) and 3 years (T3) after insertion. Repeated measures ANOVA was used for statistical analysis (α=.05). No significant difference in the survival rate (93.3% for BA and 100% for RA) was found between groups (P=.156). VBL and HBLo increased significantly at T3 compared with T1 for both groups (Poverdentures were associated with significantly higher vertical and horizontal circumferential bone loss than those associated with splinted implants after a follow-up of 3 years. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  17. Blanket Module Boil-Off Times during a Loss-of-Coolant Accident - Case 0: with Beam Shutdown only

    International Nuclear Information System (INIS)

    Hamm, L.L.

    1998-01-01

    This report is one of a series of reports that document LBLOCA analyses for the Accelerator Production of Tritium primary blanket Heat Removal system. This report documents the analysis results of a LBLOCA where the accelerator beam is shut off without primary pump trips and neither the RHR nor the cavity flood systems operation

  18. Survival After Conservative Management Versus External Beam Radiation Therapy in Elderly Patients With Localized Prostate Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Dell' Oglio, Paolo, E-mail: paolo.delloglio@gmail.com [Cancer Prognostics and Health Outcomes Unit, University of Montreal Health Center, Montreal, Québec (Canada); Department of Urology and Division of Experimental Oncology, Urological Research Institute, IRCCS San Raffaele Scientific Institute, Milan (Italy); Boehm, Katharina [Cancer Prognostics and Health Outcomes Unit, University of Montreal Health Center, Montreal, Québec (Canada); Martini-Clinic, Prostate Cancer Center Hamburg-Eppendorf, Hamburg (Germany); Trudeau, Vincent [Cancer Prognostics and Health Outcomes Unit, University of Montreal Health Center, Montreal, Québec (Canada); Department of Urology, University of Montreal Health Center, Montreal, Québec (Canada); Tian, Zhe [Cancer Prognostics and Health Outcomes Unit, University of Montreal Health Center, Montreal, Québec (Canada); Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, Québec (Canada); Larcher, Alessandro [Department of Urology and Division of Experimental Oncology, Urological Research Institute, IRCCS San Raffaele Scientific Institute, Milan (Italy); Leyh-Bannurah, Sami-Ramzi [Cancer Prognostics and Health Outcomes Unit, University of Montreal Health Center, Montreal, Québec (Canada); Martini-Clinic, Prostate Cancer Center Hamburg-Eppendorf, Hamburg (Germany); Moschini, Marco; Capitanio, Umberto [Department of Urology and Division of Experimental Oncology, Urological Research Institute, IRCCS San Raffaele Scientific Institute, Milan (Italy); Shariat, Shahrokh F. [Department of Urology, Medical University of Vienna and General Hospital, Vienna (Austria); and others

    2016-12-01

    Purpose: To compare survival in elderly men with clinically localized prostate cancer (PCa) according to treatment type, defined as radiation therapy (RT) with or without androgen deprivation therapy (ADT) versus conservative management (observation). Methods and Materials: In the Surveillance, Epidemiology, and End Results (SEER)–Medicare linked database, we identified 23,790 patients aged 80 years or more with clinically localized PCa treated with either RT or observation between 1991 and 2009. Competing risks analyses focused on cancer-specific mortality and other-cause mortality, after accounting for confounders. All analyses were repeated after stratification according to grade (well-differentiated vs moderately differentiated vs poorly differentiated disease), race, and United States region, in patients with no comorbidities and in patients with at least 1 comorbidity. Analyses were repeated within most contemporary patients, namely those treated between 2001 and 2009. Results: Radiation therapy was associated with more favorable cancer-specific mortality rates than observation in patients with moderately differentiated disease (hazard ratio [HR] 0.79; 95% confidence interval [CI] 0.66-0.94; P=.009) and in patients with poorly differentiated disease (HR 0.58; 95% CI 0.49-0.69; P<.001). Conversely, the benefit of RT was not observed in well-differentiated disease. The benefit of RT was confirmed in black men (HR 0.54; 95% CI 0.35-0.83; P=.004), across all United States regions (all P≤.004), in the subgroups of the healthiest patients (HR 0.67; 95% CI 0.57-0.78; P<.001), in patients with at least 1 comorbidity (HR 0.69; 95% CI 0.56-0.83; P<.001), and in most contemporary patients (HR 0.55; 95% CI 0.46-0.66; P<.001). Conclusions: Radiation therapy seems to be associated with a reduction in the risk of death from PCa relative to observation in elderly patients with clinically localized PCa, except for those with well-differentiated disease.

  19. Survival After Conservative Management Versus External Beam Radiation Therapy in Elderly Patients With Localized Prostate Cancer

    International Nuclear Information System (INIS)

    Dell'Oglio, Paolo; Boehm, Katharina; Trudeau, Vincent; Tian, Zhe; Larcher, Alessandro; Leyh-Bannurah, Sami-Ramzi; Moschini, Marco; Capitanio, Umberto; Shariat, Shahrokh F.

    2016-01-01

    Purpose: To compare survival in elderly men with clinically localized prostate cancer (PCa) according to treatment type, defined as radiation therapy (RT) with or without androgen deprivation therapy (ADT) versus conservative management (observation). Methods and Materials: In the Surveillance, Epidemiology, and End Results (SEER)–Medicare linked database, we identified 23,790 patients aged 80 years or more with clinically localized PCa treated with either RT or observation between 1991 and 2009. Competing risks analyses focused on cancer-specific mortality and other-cause mortality, after accounting for confounders. All analyses were repeated after stratification according to grade (well-differentiated vs moderately differentiated vs poorly differentiated disease), race, and United States region, in patients with no comorbidities and in patients with at least 1 comorbidity. Analyses were repeated within most contemporary patients, namely those treated between 2001 and 2009. Results: Radiation therapy was associated with more favorable cancer-specific mortality rates than observation in patients with moderately differentiated disease (hazard ratio [HR] 0.79; 95% confidence interval [CI] 0.66-0.94; P=.009) and in patients with poorly differentiated disease (HR 0.58; 95% CI 0.49-0.69; P<.001). Conversely, the benefit of RT was not observed in well-differentiated disease. The benefit of RT was confirmed in black men (HR 0.54; 95% CI 0.35-0.83; P=.004), across all United States regions (all P≤.004), in the subgroups of the healthiest patients (HR 0.67; 95% CI 0.57-0.78; P<.001), in patients with at least 1 comorbidity (HR 0.69; 95% CI 0.56-0.83; P<.001), and in most contemporary patients (HR 0.55; 95% CI 0.46-0.66; P<.001). Conclusions: Radiation therapy seems to be associated with a reduction in the risk of death from PCa relative to observation in elderly patients with clinically localized PCa, except for those with well-differentiated disease.

  20. Impact of Image Guidance on Outcomes After External Beam Radiotherapy for Localized Prostate Cancer

    International Nuclear Information System (INIS)

    Kupelian, Patrick A.; Willoughby, Twyla R.; Reddy, Chandana A.; Klein, Eric A.; Mahadevan, Arul

    2008-01-01

    Purpose: To verify whether rectal distention at the time of planning impacts outcomes in patients with localized prostate cancer treated with daily image guidance. Methods and Materials: Between 1998 and 2002, a total of 488 prostate cancer patients were treated with intensity-modulated radiotherapy. The radiation dose was 70 Gy delivered at 2.5 Gy per fraction in all cases. All cases were treated with a 4-mm margin posteriorly. In all cases the total rectal volume documented on the CT scan was used for treatment planning. No special bowel preparation instructions were given, either for the simulation or the daily treatments. Before each daily treatment, alignment of the prostate was performed with the B-mode acquisition and targeting (BAT) transabdominal ultrasound system. The median follow-up for all 488 patients was 60 months (range, 24-96 months). Results: For all patients the biochemical relapse-free survival (bRFS) rate at 5 years was 86%. The 5-year bRFS rate for the rectal distention 3 , 50 to 3 , and ≥100 cm 3 groups was 90%, 83%, and 85%, respectively (p = 0.18). To adjust for other potential variables affecting bRFS rates, a multivariate time-to-failure analysis using the Cox proportional hazards model was performed. Rectal distention was not an independent predictor of biochemical failure on multivariate analysis (p = 0.80). Rectal distention was not a predictor of rectal or urinary toxicity. Conclusion: The use of daily image guidance eliminates errors such as rectal distention at the initial planning stage that can affect outcomes after radiotherapy for localized prostate cancer

  1. High-Resolution, Long-Slit Spectroscopy of VY Canis Majoris: The Evidence for Localized High Mass Loss Events

    Science.gov (United States)

    Humphreys, Roberta M.; Davidson, Kris; Ruch, Gerald; Wallerstein, George

    2005-01-01

    High spatial and spectral resolution spectroscopy of the OH/IR supergiant VY CMa and its circumstellar ejecta reveals evidence for high mass loss events from localized regions on the star occurring over the past 1000 yr. The reflected absorption lines and the extremely strong K I emission lines show a complex pattern of velocities in the ejecta. We show that the large, dusty northwest arc, expanding at ~50 km s-1 with respect to the embedded star, is kinematically distinct from the surrounding nebulosity and was ejected about 400 yr ago. Other large, more filamentary loops were probably expelled as much as 800-1000 yr ago, whereas knots and small arcs close to the star resulted from more recent events 100-200 yr ago. The more diffuse, uniformly distributed gas and dust is surprisingly stationary, with little or no velocity relative to the star. This is not what we would expect for the circumstellar material from an evolved red supergiant with a long history of mass loss. We therefore suggest that the high mass loss rate for VY CMa is a measure of the mass carried out by these specific ejections accompanied by streams or flows of gas through low-density regions in the dust envelope. VY CMa may thus be our most extreme example of stellar activity, but our results also bring into question the evolutionary state of this famous star. In a separate appendix, we discuss the origin of the very strong K I and other rare emission lines in its spectrum.

  2. Comparison of the outcome and morbidity for localized or locally advanced prostate cancer treated by high-dose-rate brachytherapy plus external beam radiotherapy (EBRT) versus EBRT alone

    International Nuclear Information System (INIS)

    Fang Fumin; Wang Yuming; Wang Chongjong; Huang Hsuanying; Chiang Pohui

    2008-01-01

    The objective of this study was to compare the survival, gastrointestinal (GI) and genitourinary (GU) toxicity for localized or locally advanced prostate cancer treated by high-dose-rate-brachytherapy (HDR-BT) plus external beam radiotherapy (EBRT) versus EBRT alone at a single institute in Taiwan. Eighty-eight patients with T1c-T3b prostate cancer consecutively treated by EBRT alone (33 patients) or HDR-BT+EBRT (55 patients) were studied. The median dose of EBRT was 70.2 Gy in the EBRT group and 50.4 Gy in the HDR-BT group. HDR-BT was performed 2-3 weeks before EBRT, with 12.6 Gy in three fractions over 24 h. Five patients (15.2%) in the EBRT group and seven (12.7%) in the HDR-BT group developed a biochemical relapse. The 5-year actuarial biochemical relapse-free survival rates were 65.0% in the EBRT group and 66.7% in the HDR-BT group (P=0.76). The 5-year actuarial likelihood of late ≥Grade 2 and ≥Grade 3 GI toxicity in the EBRT versus HDR-BT group was 62.8 versus 7.7% (P<0.001) and 19.6 versus 0% (P=0.001), respectively. In a multivariate analysis, the only predictor for late GI toxicity was the mode of RT. The 5-year actuarial likelihood of late ≥Grade 2 and ≥Grade 3 GU toxicity in the EBRT versus HDR-BT group was 14.8 versus 15.9% (P=0.86) and 3.6 versus 8.5% (P=0.40), respectively. The addition of HDR-BT before EBRT with a reduced dose from the EBRT produces a comparable survival outcome and GU toxicity but a significantly less GI toxicity for prostate cancer patients. (author)

  3. Histological and elemental changes in the rat brain after local irradiation with carbon ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Sentaro; Sun, Xue-Zhi; Kubota, Yoshihisa; Takai, Nobuhiko; Nojima, Kumie [National Inst. of Radiological Sciences, Chiba (Japan)

    2002-06-01

    The left cerebral hemispheres of adult Sprague-Dawley rat brains were irradiated at doses of 30, 50, or 100 Gy with charged carbon particles (290 MeV/nucleon; 5 mm spread-out Bragg peak). The spread-out Bragg peak used here successfully and satisfactorily retained its high-dose localization in the defined region. A histological examination showed that necrotic tissue damage, hemorrhage in the thalamus, and vasodilatations around the necrotic region were induced at 8 weeks after 100 Gy irradiation. The regions with tissue damage correlated well with those expected from the radiation-dose distribution, indicating an advantage of charged carbon particles for irradiating restricted brain regions. An X-ray fluorescent analysis demonstrated a decrease in the concentrations of K and P, and an increase in the concentrations of Cl, Fe, Zn in the damaged region at 8 weeks post-irradiation, though no significant changes were observed before 4 weeks of post-irradiation. This may indicate that even the very high radiation doses used here did not induce acute and immediate neuronal cell death, in contrast with ischemic brain injury where acute neuronal cell death occurred and the elemental concentrations changed within a day after the induction of ischemia. (author)

  4. Higher order mode spectra and the dependence of localized dipole modes on the transverse beam position in third harmonic superconducting cavities at FLASH

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Pei [Manchester Univ. (United Kingdom); Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Baboi, Nicoleta [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Jones, Roger M. [The Cockcroft Institute, Daresbury (United Kingdom)

    2012-06-15

    An electron beam entering an accelerating cavity excites a wakefield. This wakefield can be decomposed into a series of multi-poles or modes. The dominant component of the transverse wakefield is dipole. This report summarizes the higher order mode (HOM) signals of the third harmonic cavities of FLASH measured at various stages: transmission measurements in the single cavity test stand at Fermilab, at CMTB (Cryo- Module Test Bench) and at FLASH, and beam-excited measurements at FLASH. Modes in the first two dipole bands and the fifth dipole band have been identified using a global Lorentzian fit technique. The beam-pipe modes at approximately 4 GHz and some modes in the fifth dipole band have been observed as localized modes, while the first two dipole bands, containing some strong coupling cavity modes, propagate. This report also presents the dependence of the localized dipole modes on the transverse beam position. Linear dependence for various modes has been observed. This makes them suitable for beam position diagnostics. These modes, together with some propagating, strong coupling modes, have been considered in the design of a dedicated electronics for beam diagnostics with HOMs for the third harmonic cavities.

  5. Tumor Localization Using Cone-Beam CT Reduces Setup Margins in Conventionally Fractionated Radiotherapy for Lung Tumors

    International Nuclear Information System (INIS)

    Yeung, Anamaria R.; Li, Jonathan G.; Shi Wenyin; Newlin, Heather E.; Chvetsov, Alexei; Liu, Chihray; Palta, Jatinder R.; Olivier, Kenneth

    2009-01-01

    Purpose: To determine whether setup margins can be reduced using cone-beam computed tomography (CBCT) to localize tumor in conventionally fractionated radiotherapy for lung tumors. Methods and Materials: A total of 22 lung cancer patients were treated with curative intent with conventionally fractionated radiotherapy using daily image guidance with CBCT. Of these, 13 lung cancer patients had sufficient CBCT scans for analysis (389 CBCT scans). The patients underwent treatment simulation in the BodyFix immobilization system using four-dimensional CT to account for respiratory motion. Daily alignment was first done according to skin tattoos, followed by CBCT. All 389 CBCT scans were retrospectively registered to the planning CT scans using automated soft-tissue and bony registration; the resulting couch shifts in three dimensions were recorded. Results: The daily alignment to skin tattoos with no image guidance resulted in systematic (Σ) and random (σ) errors of 3.2-5.6 mm and 2.0-3.5 mm, respectively. The margin required to account for the setup error introduced by aligning to skin tattoos with no image guidance was approximately 1-1.6 cm. The difference in the couch shifts obtained from the bone and soft-tissue registration resulted in systematic (Σ) and random (σ) errors of 1.5-4.1 mm and 1.8-5.3 mm, respectively. The margin required to account for the setup error introduced using bony anatomy as a surrogate for the target, instead of localizing the target itself, was 0.5-1.4 cm. Conclusion: Using daily CBCT soft-tissue registration to localize the tumor in conventionally fractionated radiotherapy reduced the required setup margin by up to approximately 1.5 cm compared with both no image guidance and image guidance using bony anatomy as a surrogate for the target.

  6. Long-Term Quality of Life Outcome After Proton Beam Monotherapy for Localized Prostate Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Coen, John J., E-mail: jcoen@partners.org [Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA (United States); Paly, Jonathan J.; Niemierko, Andrzej; Weyman, Elizabeth [Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA (United States); Rodrigues, Anita [Department of Medical Oncology, Massachusetts General Hospital, Boston, MA (United States); Shipley, William U.; Zietman, Anthony L. [Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA (United States); Talcott, James A. [Department of Medical Oncology, Massachusetts General Hospital, Boston, MA (United States)

    2012-02-01

    Objectives: High-dose external radiation for localized prostate cancer results in favorable clinical outcomes and low toxicity rates. Here, we report long-term quality of life (QOL) outcome for men treated with conformal protons. Methods: QOL questionnaires were sent at specified intervals to 95 men who received proton radiation. Of these, 87 men reported 3- and/or 12-month outcomes, whereas 73 also reported long-term outcomes (minimum 2 years). Symptom scores were calculated at baseline, 3 months, 12 months, and long-term follow-up. Generalized estimating equation models were constructed to assess longitudinal outcomes while accounting for correlation among repeated measures in an individual patient. Men were stratified into functional groups from their baseline questionnaires (normal, intermediate, or poor function) for each symptom domain. Long-term QOL changes were assessed overall and within functional groups using the Wilcoxon signed-rank test. Results: Statistically significant changes in all four symptom scores were observed in the longitudinal analysis. For the 73 men reporting long-term outcomes, there were significant change scores for incontinence (ID), bowel (BD) and sexual dysfunction (SD), but not obstructive/irritative voiding dysfunction (OID). When stratified by baseline functional category, only men with normal function had increased scores for ID and BD. For SD, there were significant changes in men with both normal and intermediate function, but not poor function. Conclusions: Patient reported outcomes are sensitive indicators of treatment-related morbidity. These results quantitate the long-term consequences of proton monotherapy for prostate cancer. Analysis by baseline functional category provides an individualized prediction of long-term QOL scores. High dose proton radiation was associated with small increases in bowel dysfunction and incontinence, with more pronounced changes in sexual dysfunction.

  7. Evaluation of tumor localization in respiration motion-corrected cone-beam CT: prospective study in lung.

    Science.gov (United States)

    Dzyubak, Oleksandr; Kincaid, Russell; Hertanto, Agung; Hu, Yu-Chi; Pham, Hai; Rimner, Andreas; Yorke, Ellen; Zhang, Qinghui; Mageras, Gig S

    2014-10-01

    Target localization accuracy of cone-beam CT (CBCT) images used in radiation treatment of respiratory disease sites is affected by motion artifacts (blurring and streaking). The authors have previously reported on a method of respiratory motion correction in thoracic CBCT at end expiration (EE). The previous retrospective study was limited to examination of reducing motion artifacts in a small number of patient cases. They report here on a prospective study in a larger group of lung cancer patients to evaluate respiratory motion-corrected (RMC)-CBCT ability to improve lung tumor localization accuracy and reduce motion artifacts in Linac-mounted CBCT images. A second study goal examines whether the motion correction derived from a respiration-correlated CT (RCCT) at simulation yields similar tumor localization accuracy at treatment. In an IRB-approved study, 19 lung cancer patients (22 tumors) received a RCCT at simulation, and on one treatment day received a RCCT, a respiratory-gated CBCT at end expiration, and a 1-min CBCT. A respiration monitor of abdominal displacement was used during all scans. In addition to a CBCT reconstruction without motion correction, the motion correction method was applied to the same 1-min scan. Projection images were sorted into ten bins based on abdominal displacement, and each bin was reconstructed to produce ten intermediate CBCT images. Each intermediate CBCT was deformed to the end expiration state using a motion model derived from RCCT. The deformed intermediate CBCT images were then added to produce a final RMC-CBCT. In order to evaluate the second study goal, the CBCT was corrected in two ways, one using a model derived from the RCCT at simulation [RMC-CBCT(sim)], the other from the RCCT at treatment [RMC-CBCT(tx)]. Image evaluation compared uncorrected CBCT, RMC-CBCT(sim), and RMC-CBCT(tx). The gated CBCT at end expiration served as the criterion standard for comparison. Using automatic rigid image registration, each CBCT was

  8. Evaluation of tumor localization in respiration motion-corrected cone-beam CT: Prospective study in lung

    Energy Technology Data Exchange (ETDEWEB)

    Dzyubak, Oleksandr; Kincaid, Russell; Hertanto, Agung; Hu, Yu-Chi; Pham, Hai; Yorke, Ellen; Zhang, Qinghui; Mageras, Gig S., E-mail: magerasg@mskcc.org [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York 10065 (United States); Rimner, Andreas [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York 10065 (United States)

    2014-10-15

    Purpose: Target localization accuracy of cone-beam CT (CBCT) images used in radiation treatment of respiratory disease sites is affected by motion artifacts (blurring and streaking). The authors have previously reported on a method of respiratory motion correction in thoracic CBCT at end expiration (EE). The previous retrospective study was limited to examination of reducing motion artifacts in a small number of patient cases. They report here on a prospective study in a larger group of lung cancer patients to evaluate respiratory motion-corrected (RMC)-CBCT ability to improve lung tumor localization accuracy and reduce motion artifacts in Linac-mounted CBCT images. A second study goal examines whether the motion correction derived from a respiration-correlated CT (RCCT) at simulation yields similar tumor localization accuracy at treatment. Methods: In an IRB-approved study, 19 lung cancer patients (22 tumors) received a RCCT at simulation, and on one treatment day received a RCCT, a respiratory-gated CBCT at end expiration, and a 1-min CBCT. A respiration monitor of abdominal displacement was used during all scans. In addition to a CBCT reconstruction without motion correction, the motion correction method was applied to the same 1-min scan. Projection images were sorted into ten bins based on abdominal displacement, and each bin was reconstructed to produce ten intermediate CBCT images. Each intermediate CBCT was deformed to the end expiration state using a motion model derived from RCCT. The deformed intermediate CBCT images were then added to produce a final RMC-CBCT. In order to evaluate the second study goal, the CBCT was corrected in two ways, one using a model derived from the RCCT at simulation [RMC-CBCT(sim)], the other from the RCCT at treatment [RMC-CBCT(tx)]. Image evaluation compared uncorrected CBCT, RMC-CBCT(sim), and RMC-CBCT(tx). The gated CBCT at end expiration served as the criterion standard for comparison. Using automatic rigid image

  9. SU-G-JeP1-01: A Combination of Real Time Electromagnetic Localization and Tracking with Cone Beam Computed Tomography in Stereotactic Radiosurgery for Brain Tumors

    International Nuclear Information System (INIS)

    Muralidhar, K Raja; Pangam, Suresh; Ponaganti, Srinivas; Krishna, Jayarama; Sujana, Kolla V; Komanduri, Priya K

    2016-01-01

    Purpose: 1. online verification of patient position during treatment using calypso electromagnetic localization and tracking system. 2. Verification and comparison of positional accuracy between cone beam computed tomography and calypso system. 3. Presenting the advantage of continuation localization in Stereotactic radiosurgery treatments. Methods: Ten brain tumor cases were taken for this study. Patients with head mask were under gone Computed Tomography (CT). Before scanning, mask was cut on the fore head area to keep surface beacons on the skin. Slice thickness of 0.65 mm were taken for this study. x, y, z coordinates of these beacons in TPS were entered into tracking station. Varian True Beam accelerator, equipped with On Board Imager was used to take Cone beam Computed Tomography (CBCT) to localize the patient. Simultaneously Surface beacons were used to localize and track the patient throughout the treatment. The localization values were compared in both systems. For localization CBCT considered as reference. Tracking was done throughout the treatment using Calypso tracking system using electromagnetic array. This array was in tracking position during imaging and treatment. Flattening Filter free beams of 6MV photons along with Volumetric Modulated Arc Therapy was used for the treatment. The patient movement was observed throughout the treatment ranging from 2 min to 4 min. Results: The average variation observed between calypso system and CBCT localization was less than 0.5 mm. These variations were due to manual errors while keeping beacon on the patient. Less than 0.05 cm intra-fraction motion was observed throughout the treatment with the help of continuous tracking. Conclusion: Calypso target localization system is one of the finest tools to perform radiosurgery in combination with CBCT. This non radiographic method of tracking is a real beneficial method to treat patients confidently while observing real-time motion information of the patient.

  10. SU-G-JeP1-01: A Combination of Real Time Electromagnetic Localization and Tracking with Cone Beam Computed Tomography in Stereotactic Radiosurgery for Brain Tumors

    Energy Technology Data Exchange (ETDEWEB)

    Muralidhar, K Raja; Pangam, Suresh; Ponaganti, Srinivas; Krishna, Jayarama; Sujana, Kolla V; Komanduri, Priya K [American Oncology Institute, Hyderabad, Telangana (India)

    2016-06-15

    Purpose: 1. online verification of patient position during treatment using calypso electromagnetic localization and tracking system. 2. Verification and comparison of positional accuracy between cone beam computed tomography and calypso system. 3. Presenting the advantage of continuation localization in Stereotactic radiosurgery treatments. Methods: Ten brain tumor cases were taken for this study. Patients with head mask were under gone Computed Tomography (CT). Before scanning, mask was cut on the fore head area to keep surface beacons on the skin. Slice thickness of 0.65 mm were taken for this study. x, y, z coordinates of these beacons in TPS were entered into tracking station. Varian True Beam accelerator, equipped with On Board Imager was used to take Cone beam Computed Tomography (CBCT) to localize the patient. Simultaneously Surface beacons were used to localize and track the patient throughout the treatment. The localization values were compared in both systems. For localization CBCT considered as reference. Tracking was done throughout the treatment using Calypso tracking system using electromagnetic array. This array was in tracking position during imaging and treatment. Flattening Filter free beams of 6MV photons along with Volumetric Modulated Arc Therapy was used for the treatment. The patient movement was observed throughout the treatment ranging from 2 min to 4 min. Results: The average variation observed between calypso system and CBCT localization was less than 0.5 mm. These variations were due to manual errors while keeping beacon on the patient. Less than 0.05 cm intra-fraction motion was observed throughout the treatment with the help of continuous tracking. Conclusion: Calypso target localization system is one of the finest tools to perform radiosurgery in combination with CBCT. This non radiographic method of tracking is a real beneficial method to treat patients confidently while observing real-time motion information of the patient.

  11. Feasibility of Pencil Beam Scanned Intensity Modulated Proton Therapy in Breath-hold for Locally Advanced Non-Small Cell Lung Cancer

    DEFF Research Database (Denmark)

    Gorgisyan, Jenny; Munck Af Rosenschold, Per; Perrin, Rosalind

    2017-01-01

    PURPOSE: We evaluated the feasibility of treating patients with locally advanced non-small cell lung cancer (NSCLC) with pencil beam scanned intensity modulated proton therapy (IMPT) in breath-hold. METHODS AND MATERIALS: Fifteen NSCLC patients who had previously received 66 Gy in 33 fractions wi...

  12. A Phase Space Monitoring of Injected Beam of J-PARC MR

    Science.gov (United States)

    Hatakeyama, Shuichiro; Toyama, Takeshi

    Beam power of J-PARC MR (30 GeV Proton Synchrotron Main Ring) has been improved since 2008 and now achieved over 200 kW for the user operation. A part of beam loss is localized at the beam injection phase so it is important to monitor the beam bunch behavior in the transverse direction. In this paper it is described the method how to measure the position and momentum for each injected beam bunch using Beam Position Monitors (BPMs). It is also mentioned some implementation of an operator's interface (OPI) to display the plots of injected and circulating beam bunches in phase space coordinate.

  13. Comparison of mega-voltage cone-beam computed tomography prostate localization with online ultrasound and fiducial markers methods.

    Science.gov (United States)

    Gayou, Olivier; Miften, Moyed

    2008-02-01

    The online image-guided localization data from 696 ultrasound (US), 598 mega-voltage cone-beam computed tomography (MV-CBCT), and 393 seed markers (SMs) couch alignments for patients undergoing intensity modulation radiotherapy of the prostate were analyzed. Daily US, MV-CBCT and SM images were acquired for 19, 17 and 12 patients, respectively, after each patient was immobilized in a vacuum cradle and setup to skin markers as the center of mass. The couch shifts applied in the lateral (left-right/LR), vertical (anterior-posterior/AP), and longitudinal (superior-inferior/SI) directions, along with the magnitude of the three-dimensional (3D) shift vector, were analyzed and compared for all three methods. The percentage of shifts larger than 5 mm in all directions was also compared. Clinical target volume-planning target volume (CTV-to-PTV) expansion margins were estimated based on the localization data with US, CB, and SM image guidance. Results show the US data have greater variability. Systematic and random shifts were -1.2 +/- 6.8 mm (LR), -2.8 +/- 5.1 mm (SI) and -1.0 +/- 5.9 mm (AP) for US, 1.0 +/- 3.9 mm (LR), -1.3 +/- 2.5 mm (SI) and -0.3 +/- 3.9 mm (AP) for CB, and -1.0 +/- 3.4 mm (LR), 0.0 +/- 3.4 mm (SI) and 0.5 +/- 4.1 mm (AP) for SM. The mean 3D shift distance was larger using US (8.8 +/- 6.2 mm) compared to CB and SM (5.3 +/- 3.4 mm and 5.2 +/- 3.7 mm, respectively). The percentage of US shifts larger than 5 mm were 34%, 31%, and 38% in the LR, SI, and AP directions, respectively, compared to 18%, 6%, and 16% for CB and 14%, 10%, and 20% for SM. MV-CBCT and SM localization data suggest a different distribution of prostate center-of-mass shifts with smaller variability, compared to US. The online MV-CBCT and SM image-guidance data show that for treatments that do not include daily prostate localization, one can use a CTV-to-PTV margin that is 4 mm smaller than the one suggested by US data, hence allowing more rectum and bladder sparing and potentially

  14. Radiolabeled anti-EGFR-antibody improves local tumor control after external beam radiotherapy and offers theragnostic potential

    International Nuclear Information System (INIS)

    Koi, Lydia; Bergmann, Ralf; Brüchner, Kerstin; Pietzsch, Jens; Pietzsch, Hans-Jürgen; Krause, Mechthild

    2014-01-01

    Purpose: The effect of radioimmunotherapy (RIT) using the therapeutic radionuclide Y-90 bound to the anti-EGFR antibody cetuximab combined with external beam irradiation (EBRT) (EBRIT) on permanent local tumor control in vivo was examined. Methods: Growth delay was evaluated in three human squamous cell carcinoma models after RIT with [ 90 Y]Y-(CHX-A′′-DTPA) 4 -cetuximab (Y-90-cetuximab). The EBRT dose required to cure 50% of the tumors (TCD 50 ) for EBRT alone or EBRIT was evaluated in one RIT-responder (FaDu) and one RIT-non-responder (UT-SCC-5). EGFR expression and microenvironmental parameters were evaluated in untreated tumors, bioavailability was visualized by PET using ([ 86 Y]Y-(CHX-A′′-DTPA) 4 -cetuximab (Y-86-cetuximab) and biodistribution using Y-90-cetuximab. Results: In UT-SCC-8 and FaDu but not in UT-SCC-5 radiolabeled cetuximab led to significant tumor growth delay. TCD 50 after EBRT was significantly decreased by EGFR-targeted RIT in FaDu but not in UT-SCC-5. In contrast to EGFR expression, parameters of the tumor micromilieu and in particular the Y-90-cetuximab biodistribution or Y-86-cetuximab visualization in PET correlated with the responsiveness to RIT or EBRIT. Conclusion: EGFR-targeted EBRIT can improve permanent local tumor control compared to EBRT alone. PET imaging of bioavailability of labeled cetuximab appears to be a suitable predictor for response to EBRIT. This theragnostic approach should be further explored for clinical translation

  15. Global and local characteristics of an autogenous single pass electron beam weld in thick gage UNS S41500 steel

    Energy Technology Data Exchange (ETDEWEB)

    Sarafan, S., E-mail: Sheida.Sarafan.1@ens.etsmtl.ca [École de Technologie Supérieure, Montréal, Québec, Canada H3C 1K3 (Canada); National Research Council Canada, Aerospace, Montréal, Québec, Canada H3T 2B2 (Canada); Wanjara, P., E-mail: priti.wanjara@nrc-cnrc.gc.ca [National Research Council Canada, Aerospace, Montréal, Québec, Canada H3T 2B2 (Canada); Gholipour, J., E-mail: Javad.gholipour@nrc-cnrc.gc.ca [National Research Council Canada, Aerospace, Montréal, Québec, Canada H3T 2B2 (Canada); Champliaud, H., E-mail: henri.champliaud@etsmtl.ca [École de Technologie Supérieure, Montréal, Québec, Canada H3C 1K3 (Canada)

    2016-06-01

    Electron beam welding of UNS S41500, a low carbon martensitic stainless steel utilized in hydroelectric turbine manufacturing, was investigated by applying a single pass autogenous process to penetrate a section thickness of 72 mm without preheating. In the as-welded and post-weld heat treated conditions, the evolution in microhardness and microstructure across the weldments, as well as the global and local tensile properties, were evaluated. In the as-welded condition, assessment of the microhardness and the associated microstructure across the welds led to the identification of six regions, including the fusion zone, four heat affected zones and the base metal; each of these regions consisted of different phase constituents, such as tempered martensite, untempered martensite, delta ferrite and retained austenite. Post-weld heat treatment, undertaken to temper the untempered martensite in the as-welded microstructure, was effective in homogenizing the hardness across the weldment. The mechanical response of the welds, determined through tensile testing at room temperature with an automated non-contact three-dimensional deformation measurement system, indicated that the global tensile properties in the as-welded and post-weld heat treated conditions met the acceptance criteria in the ASME Section IX standard. Also, evaluation of the local tensile properties in the fusion and heat affected zones of the as-welded samples allowed a more comprehensive understanding of the strength and ductility associated with the different microstructures in the “composite” nature of the weldment. Fractographic analysis demonstrated dimpled features on the tensile fracture surfaces and failure was associated with debonding between the martensitic matrix and the secondary phases (such as delta ferrite and retained austenite) that resulted in the formation, growth and coalescence of voids into a macroscale crack.

  16. Conventional and conformal technique of external beam radiotherapy in locally advanced cervical cancer: Dose distribution, tumor response, and side effects

    Science.gov (United States)

    Mutrikah, N.; Winarno, H.; Amalia, T.; Djakaria, M.

    2017-08-01

    The objective of this study was to compare conventional and conformal techniques of external beam radiotherapy (EBRT) in terms of the dose distribution, tumor response, and side effects in the treatment of locally advanced cervical cancer patients. A retrospective cohort study was conducted on cervical cancer patients who underwent EBRT before brachytherapy in the Radiotherapy Department of Cipto Mangunkusumo Hospital. The prescribed dose distribution, tumor response, and acute side effects of EBRT using conventional and conformal techniques were investigated. In total, 51 patients who underwent EBRT using conventional techniques (25 cases using Cobalt-60 and 26 cases using a linear accelerator (LINAC)) and 29 patients who underwent EBRT using conformal techniques were included in the study. The distribution of the prescribed dose in the target had an impact on the patient’s final response to EBRT. The complete response rate of patients to conformal techniques was significantly greater (58%) than that of patients to conventional techniques (42%). No severe acute local side effects were seen in any of the patients (Radiation Therapy Oncology Group (RTOG) grades 3-4). The distribution of the dose and volume to the gastrointestinal tract affected the proportion of mild acute side effects (RTOG grades 1-2). The urinary bladder was significantly greater using conventional techniques (Cobalt-60/LINAC) than using conformal techniques at 72% and 78% compared to 28% and 22%, respectively. The use of conformal techniques in pelvic radiation therapy is suggested in radiotherapy centers with CT simulators and 3D Radiotherapy Treatment Planning Systems (RTPSs) to decrease some uncertainties in radiotherapy planning. The use of AP/PA pelvic radiation techniques with Cobalt-60 should be limited in body thicknesses equal to or less than 18 cm. When using conformal techniques, delineation should be applied in the small bowel, as it is considered a critical organ according to RTOG

  17. Residual rotational set-up errors after daily cone-beam CT image guided radiotherapy of locally advanced cervical cancer

    International Nuclear Information System (INIS)

    Laursen, Louise Vagner; Elstrøm, Ulrik Vindelev; Vestergaard, Anne; Muren, Ludvig P.; Petersen, Jørgen Baltzer; Lindegaard, Jacob Christian; Grau, Cai; Tanderup, Kari

    2012-01-01

    Purpose: Due to the often quite extended treatment fields in cervical cancer radiotherapy, uncorrected rotational set-up errors result in a potential risk of target miss. This study reports on the residual rotational set-up error after using daily cone beam computed tomography (CBCT) to position cervical cancer patients for radiotherapy treatment. Methods and materials: Twenty-five patients with locally advanced cervical cancer had daily CBCT scans (650 CBCTs in total) prior to treatment delivery. We retrospectively analyzed the translational shifts made in the clinic prior to each treatment fraction as well as the residual rotational errors remaining after translational correction. Results: The CBCT-guided couch movement resulted in a mean translational 3D vector correction of 7.4 mm. Residual rotational error resulted in a target shift exceeding 5 mm in 57 of the 650 treatment fractions. Three patients alone accounted for 30 of these fractions. Nine patients had no shifts exceeding 5 mm and 13 patients had 5 or less treatment fractions with such shifts. Conclusion: Twenty-two of the 25 patients have none or few treatment fractions with target shifts larger than 5 mm due to residual rotational error. However, three patients display a significant number of shifts suggesting a more systematic set-up error.

  18. BNL alternating gradient synchrotron with four helical magnets to minimize the losses of the polarized proton beam

    Directory of Open Access Journals (Sweden)

    N. Tsoupas

    2013-04-01

    Full Text Available The principle of using multiple partial helical magnets to preserve the polarization of the proton beam during its acceleration was applied successfully to the alternating gradient synchrotron (AGS which currently operates with two partial helical magnets. In this paper we further explore this idea by using four partial helical magnets placed symmetrically in the AGS ring. This provides many advantages over the present setup of the AGS, which uses two partial helical magnets. First, the symmetric placement of the four helical magnets and their relatively lower field of operation allows for better control of the AGS optics with reduced values of the beta functions especially near beam injection and allows both the vertical and horizontal tunes to be placed within the “spin tune gap,” therefore eliminating the horizontal and vertical intrinsic spin resonances of the AGS during the acceleration cycle. Second, it provides a wider spin tune gap. Third, the vertical spin direction during beam injection and extraction is closer to vertical. Although the spin tune gap, which is created with four partial helices, can also be created with a single or two partial helices, the high field strength of a single helical magnet which is required to generate such a spin tune gap makes the use of the single helical magnet impractical, and that of the two helical magnets rather difficult. In this paper we will provide results on the spin tune and on the optics of the AGS with four partial helical magnets, and compare them with those from the present setup of the AGS that uses two partial helical magnets. Although in this paper we specifically discuss the effect of the four partial helices on the AGS, this method which can eliminate simultaneously the vertical and horizontal intrinsic spin resonances is a general method and can be applied to any medium energy synchrotron which operates in similar energy range like the AGS and provides the required space to

  19. Polarized proton beams

    International Nuclear Information System (INIS)

    Roser, T.

    1995-01-01

    The acceleration of polarized proton beams in circular accelerators is complicated by the presence of numerous depolarizing spin resonances. Careful and tedious minimization of polarization loss at each of these resonances allowed acceleration of polarized proton beams up to 22 GeV. It has been the hope that Siberian Snakes, which are local spin rotators inserted into ring accelerators, would eliminate these resonances and allow acceleration of polarized beams with the same ease and efficiency that is now routine for unpolarized beams. First tests at IUCF with a full Siberian Snake showed that the spin dynamics with a Snake can be understood in detail. The author now has results of the first tests of a partial Siberian Snake at the AGS, accelerating polarized protons to an energy of about 25 GeV. These successful tests of storage and acceleration of polarized proton beams open up new possibilities such as stored polarized beams for internal target experiments and high energy polarized proton colliders

  20. Simulation studies of macroparticles falling into the LHC Proton Beam

    CERN Document Server

    Fuster Martinez, N; Zimmermann, F; Baer, T; Giovannozzi, M; Holzer, E B; Nebot Del Busto, E; Nordt, A; Sapinski, M; Yang, Z

    2011-01-01

    We report updated simulations on the interaction of macroparticles falling from the top of the vacuum chamber into the circulating LHC proton beam. The path and charge state of micron size micro-particles are computed together with the resulting beam losses, which — if high enough — can lead to the local quench of superconducting (SC) magnets. The simulated time evolution of the beam loss is compared with observations in order to constrain some macroparticle parameters. We also discuss the possibility of a “multiple crossing” by the same macroparticle, the effect of a strong dipole field, and the dependence of peak loss rate and loss duration on beam current and on beam size.

  1. Studying substrate effects on localized surface plasmons in an individual silver nanoparticle using electron energy-loss spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Fujiyoshi, Yoshifumi; Nemoto, Takashi; Kurata, Hiroki, E-mail: kurata@eels.kuicr.kyoto-u.ac.jp

    2017-04-15

    In this study, electron energy-loss spectroscopy (EELS) in conjunction with scanning transmission electron microscopy (STEM) was used to investigate surface plasmons in a single silver nanoparticle (NP) on a magnesium oxide substrate, employing an incident electron trajectory parallel to the substrate surface. This parallel irradiation allowed a direct exploration of the substrate effects on localized surface plasmon (LSP) excitations as a function of the distance from the substrate. The presence of the substrate was found to lower the symmetry of the system, such that the resonance energies of LSPs were dependent on the polarization direction relative to the substrate surface. The resulting mode splitting could be detected by applying different electron trajectories, providing results similar to those previously obtained from optical studies using polarized light. However, the LSP maps obtained by STEM-EELS analysis show an asymmetric intensity distribution with the highest intensity at the top surface of the NP (that is, far from the substrate), a result that is not predicted by optical simulations. We show that modifications of the applied electric field by the substrate cause this asymmetric intensity distribution in the LSP maps.

  2. Dose distribution in the area of the operative cicatrice and the problem of local reccurences during postoperative external beam gamma therapy of breast cancer

    International Nuclear Information System (INIS)

    Todorov, Y.; Ivanova, K.; Penchev, V.

    1982-01-01

    Five-year experience is recorded with treatment of 503 patients with breast cancer, who received postoperative external beam gamma therapy, and the developement of local reccurences. Results are reported of dosimetric studies in the irradiated area, especially the thoracic wall, where total focal doses of 50 had been realized. The clinical results of treatment are discussed on this basis. Comparison is made with data available in the literature on the incidence, localization and time of development of local reccurences and the methods of treatment of the basic disease. The need of postoperative radiation treatment, particularly in the later stages of the disease, is pointed out. (authors)

  3. SU-F-P-30: Clinical Assessment of Auto Beam-Hold Triggered by Fiducial Localization During Prostate RapidArc Delivery

    Energy Technology Data Exchange (ETDEWEB)

    Atkinson, P; Chen, Q [Flower Hospital, Sylvania, OH (United States)

    2016-06-15

    Purpose: To assess the clinical efficacy of auto beam hold during prostate RapidArc delivery, triggered by fiducial localization on kV imaging with a Varian True Beam. Methods: Prostate patients with four gold fiducials were candidates in this study. Daily setup was accomplished by aligning to fiducials using orthogonal kV imaging. During RapidArc delivery, a kV image was automatically acquired with a momentary beam hold every 60 degrees of gantry rotation. The position of each fiducial was identified by a search algorithm and compared to a predetermined 1.4 cm diameter target area. Treatment continued if all the fiducials were within the target area. If any fiducial was outside the target area the beam hold was not released, and the operators determined if the patient needed re-alignment using the daily setup method. Results: Four patients were initially selected. For three patients, the auto beam hold performed seamlessly. In one instance, the system correctly identified misaligned fiducials, stopped treatment, and the patient was re-positioned. The fourth patient had a prosthetic hip which sometimes blocked the fiducials and caused the fiducial search algorithm to fail. The auto beam hold was disabled for this patient and the therapists manually monitored the fiducial positions during treatment. Average delivery time for a 2-arc fraction was increased by 59 seconds. Phantom studies indicated the dose discrepancy related to multiple beam holds is <0.1%. For a plan with 43 fractions, the additional imaging increased dose by an estimated 68 cGy. Conclusion: Automated intrafraction kV imaging can effectively perform auto beam holds due to patient movement, with the exception of prosthetic hip patients. The additional imaging dose and delivery time are clinically acceptable. It may be a cost-effective alternative to Calypso in RapidArc prostate patient delivery. Further study is warranted to explore its feasibility under various clinical conditions.

  4. SU-F-P-30: Clinical Assessment of Auto Beam-Hold Triggered by Fiducial Localization During Prostate RapidArc Delivery

    International Nuclear Information System (INIS)

    Atkinson, P; Chen, Q

    2016-01-01

    Purpose: To assess the clinical efficacy of auto beam hold during prostate RapidArc delivery, triggered by fiducial localization on kV imaging with a Varian True Beam. Methods: Prostate patients with four gold fiducials were candidates in this study. Daily setup was accomplished by aligning to fiducials using orthogonal kV imaging. During RapidArc delivery, a kV image was automatically acquired with a momentary beam hold every 60 degrees of gantry rotation. The position of each fiducial was identified by a search algorithm and compared to a predetermined 1.4 cm diameter target area. Treatment continued if all the fiducials were within the target area. If any fiducial was outside the target area the beam hold was not released, and the operators determined if the patient needed re-alignment using the daily setup method. Results: Four patients were initially selected. For three patients, the auto beam hold performed seamlessly. In one instance, the system correctly identified misaligned fiducials, stopped treatment, and the patient was re-positioned. The fourth patient had a prosthetic hip which sometimes blocked the fiducials and caused the fiducial search algorithm to fail. The auto beam hold was disabled for this patient and the therapists manually monitored the fiducial positions during treatment. Average delivery time for a 2-arc fraction was increased by 59 seconds. Phantom studies indicated the dose discrepancy related to multiple beam holds is <0.1%. For a plan with 43 fractions, the additional imaging increased dose by an estimated 68 cGy. Conclusion: Automated intrafraction kV imaging can effectively perform auto beam holds due to patient movement, with the exception of prosthetic hip patients. The additional imaging dose and delivery time are clinically acceptable. It may be a cost-effective alternative to Calypso in RapidArc prostate patient delivery. Further study is warranted to explore its feasibility under various clinical conditions.

  5. Contribution of monaural and binaural cues to sound localization in listeners with acquired unilateral conductive hearing loss: improved directional hearing with a bone-conduction device.

    Science.gov (United States)

    Agterberg, Martijn J H; Snik, Ad F M; Hol, Myrthe K S; Van Wanrooij, Marc M; Van Opstal, A John

    2012-04-01

    Sound localization in the horizontal (azimuth) plane relies mainly on interaural time differences (ITDs) and interaural level differences (ILDs). Both are distorted in listeners with acquired unilateral conductive hearing loss (UCHL), reducing their ability to localize sound. Several studies demonstrated that UCHL listeners had some ability to localize sound in azimuth. To test whether listeners with acquired UCHL use strongly perturbed binaural difference cues, we measured localization while they listened with a sound-attenuating earmuff over their impaired ear. We also tested the potential use of monaural pinna-induced spectral-shape cues for localization in azimuth and elevation, by filling the cavities of the pinna of their better-hearing ear with a mould. These conditions were tested while a bone-conduction device (BCD), fitted to all UCHL listeners in order to provide hearing from the impaired side, was turned off. We varied stimulus presentation levels to investigate whether UCHL listeners were using sound level as an azimuth cue. Furthermore, we examined whether horizontal sound-localization abilities improved when listeners used their BCD. Ten control listeners without hearing loss demonstrated a significant decrease in their localization abilities when they listened with a monaural plug and muff. In 4/13 UCHL listeners we observed good horizontal localization of 65 dB SPL broadband noises with their BCD turned off. Localization was strongly impaired when the impaired ear was covered with the muff. The mould in the good ear of listeners with UCHL deteriorated the localization of broadband sounds presented at 45 dB SPL. This demonstrates that they used pinna cues to localize sounds presented at low levels. Our data demonstrate that UCHL listeners have learned to adapt their localization strategies under a wide variety of hearing conditions and that sound-localization abilities improved with their BCD turned on.

  6. Numerical analysis of ac loss in bifilar stacks and coils of ion beam assisted deposition YBCO coated conductors

    International Nuclear Information System (INIS)

    Nguyen, Doan N.; Ashworth, Stephen P.; Willis, Jeffrey O.

    2009-01-01

    In this paper we present a finite element model using the commercial COMSOL software package for calculating the ac loss in bifilar stacks of high temperature superconducting tape. In the model, the current-voltage relationship characterizing the superconducting properties is assumed to follow a power law. The calculations were performed for infinite bifilar stacks with different values of layer-to-layer separation D. With appropriate settings for the boundary conditions, the numerical results agree well with the analytical data obtained from a recently proposed model [J. R. Clem, Phys. Rev. B 77, 134506 (2008)]. The numerical approach was also used to investigate the end effects in a bifilar stack to answer the following question: how many layers away from the end of a stack are required before the environment of a given layer is identical to that in an infinite stack? We find that the answer to this question depends strongly on the value of D. Based on this study, a model for calculating the ac loss in bifilar noninductively wound coils with a finite number of turns is proposed

  7. Barkas effect, shell correction, screening and correlation in collisional energy-loss straggling of an ion beam

    CERN Document Server

    Sigmund, P

    2003-01-01

    Collisional electronic energy-loss straggling has been treated theoretically on the basis of the binary theory of electronic stopping. In view of the absence of a Bloch correction in straggling the range of validity of the theory includes both the classical and the Born regime. The theory incorporates Barkas effect and projectile screening. Shell correction and electron bunching are added on. In the absence of shell corrections the Barkas effect has a dominating influence on straggling, but much of this is wiped out when the shell correction is included. Weak projectile screening tends to noticeably reduce collisional straggling. Sizable bunching effects are found in particular for heavy ions. Comparisons are made with selected results of the experimental and theoretical literature. (authors)

  8. Patient costs associated with external beam radiotherapy treatment for localized prostate cancer: the benefits of hypofractionated over conventionally fractionated radiotherapy.

    Science.gov (United States)

    Sethukavalan, Perakaa; Cheung, Patrick; Tang, Colin I; Quon, Harvey; Morton, Gerard; Nam, Robert; Loblaw, Andrew

    2012-04-01

    To estimate the out-of-pocket costs for patients undergoing external beam radiotherapy (EBRT) for prostate cancer and calculate the patient-related savings of being treated with a 5-fraction versus a standard 39-fraction approach. Seventy patients accrued to the pHART3 (n = 84) study were analyzed for out-of-pocket patient costs as a result of undergoing treatment. All costs are in Canadian dollars. Using the postal code of the patient's residence, the distance between the hospital and patient home was found using Google Maps. The Canada Revenue Agency automobile allowance rate was then applied to determine the cost per kilometer driven. The average cost of travel from the hospital and pHART3 patient's residence was $246 per person after five trips. In a standard fractionation regimen, pHART3 patients would have incurred an average cost of $1921 after 39 visits. The patients receiving hypofractionated radiotherapy would have paid an average of $38 in parking while those receiving conventional treatment would have paid $293. The difference in out-of-pocket costs for the patients receiving a standard versus hypofractionated treatment was $1930. Medium term prospective data shows that hypofractionated radiotherapy is an effective treatment method for localized prostate cancer. Compared to standard EBRT, hypofractionated radiotherapy requires significantly fewer visits. Due to the long distance patients may have to travel to the cancer center and the expense of parking, the short course treatment saves each patient an average of $1900. A randomized study of standard versus hypofractionated accelerated radiotherapy should be conducted to confirm a favorable efficacy and tolerability profile of the shorter fractionation scheme.

  9. Radical External Beam Radiotherapy for Clinically Localized Prostate Cancer in Japan: Changing Trends in the Patterns of Care Process Survey

    Energy Technology Data Exchange (ETDEWEB)

    Ogawa, Kazuhiko, E-mail: kogawa@med.u-ryukyu.ac.jp [Department of Radiology, University of the Ryukyus, Okinawa (Japan); Nakamura, Katsumasa [Department of Clinical Radiology, Kyushu University Hospital at Beppu, Oita (Japan); Sasaki, Tomonari [Department of Radiation Oncology, National Kyushu Center, Fukuoka (Japan); Onishi, Hiroshi [Department of Radiology, Yamanashi University, Yamanashi (Japan); Koizumi, Masahiko [Department of Radiation Oncology, Osaka University, Osaka (Japan); Araya, Masayuki [Department of Radiology, Yamanashi University, Yamanashi (Japan); Mukumoto, Nobutaka; Teshima, Teruki [Department of Medical Physics and Engineering, Osaka University, Osaka (Japan); Mitsumori, Michihide [Department of Radiation Oncology and Image-Applied Therapy, Kyoto University, Kyoto (Japan)

    2011-12-01

    Purpose: To delineate changing trends in radical external beam radiotherapy (EBRT) for prostate cancer in Japan. Methods and Materials: Data from 841 patients with clinically localized prostate cancer treated with EBRT in the Japanese Patterns of Care Study (PCS) from 1996 to 2005 were analyzed. Results: Significant increases in the proportions of patients with stage T1 to T2 disease and decrease in prostate-specific antigen values were observed. Also, there were significant increases in the percentages of patients treated with radiotherapy by their own choice. Median radiation doses were 65.0 Gy and 68.4 Gy from 1996 to 1998 and from 1999 to 2001, respectively, increasing to 70 Gy from 2003 to 2005. Moreover, conformal therapy was more frequently used from 2003 to 2005 (84.9%) than from 1996 to 1998 (49.1%) and from 1999 to 2001 (50.2%). On the other hand, the percentage of patients receiving hormone therapy from 2003 to 2005 (81.1%) was almost the same as that from 1996 to 1998 (86.3%) and from 1999 to 2001 (89.7%). Compared with the PCS in the United States, patient characteristics and patterns of treatments from 2003 to 2005 have become more similar to those in the United States than those from 1996 to 1998 and those from 1999 to 2001. Conclusions: This study indicates a trend toward increasing numbers of patients with early-stage disease and increasing proportions of patients treated with higher radiation doses with advanced equipment among Japanese prostate cancer patients treated with EBRT during 1996 to 2005 survey periods. Patterns of care for prostate cancer in Japan are becoming more similar to those in the United States.

  10. Energy-loss straggling study of proton and alpha-particle beams incident onto ZrO{sub 2} and Al{sub 2}O{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Behar, M.; Fadanelli, R.C. [Instituto de Fisica, Universidade Federal do Rio Grande do Sul, Porto Alegre, 91501-970 (Brazil); Abril, I. [Departamento de Fisica Aplicada, Universitat d' Alacant, 03080 Alacant (Spain); Garcia-Molina, R. [Departamento de Fisica, Centro de Investigacion en Optica y Nanofisica, Universidad de Murcia, 30100 Murcia (Spain); Nagamine, L.C.C. [Instituto de Fisica, Universidade de Sao Paulo, C.P.66318, 05315-970 Sao Paulo (Brazil)

    2011-10-15

    The energy-loss straggling of zirconia (ZrO{sub 2}) and alumina (Al{sub 2}O{sub 3}) has been experimentally determined for proton and alpha-particle beams mainly by means of the Rutherford backscattering technique and in some few cases using the transmission method. The incident energies of the projectiles covers a wide range, from 200 keV up to 2000 keV for H{sup +} and from 200 keV up to 4000 keV for He{sup +} in zirconia films. In the case of alumina films the studied energy range was 100 keV - 3000 keV for H{sup +} and 100 keV - 6000 keV for He{sup +}. Our experimental results compare very well with theoretical calculations based on the dielectric formalism and a suitable description of the electronic excitation spectrum of ZrO{sub 2} and Al{sub 2}O{sub 3} films through their energy-loss function. (authors)

  11. local

    Directory of Open Access Journals (Sweden)

    Abílio Amiguinho

    2005-01-01

    Full Text Available The process of socio-educational territorialisation in rural contexts is the topic of this text. The theme corresponds to a challenge to address it having as main axis of discussion either the problem of social exclusion or that of local development. The reasons to locate the discussion in this last field of analysis are discussed in the first part of the text. Theoretical and political reasons are there articulated because the question is about projects whose intentions and practices call for the political both in the theoretical debate and in the choices that anticipate intervention. From research conducted for several years, I use contributions that aim at discuss and enlighten how school can be a potential locus of local development. Its identification and recognition as local institution (either because of those that work and live in it or because of those that act in the surrounding context are crucial steps to progressively constitute school as a partner for development. The promotion of the local values and roots, the reconstruction of socio-personal and local identities, the production of sociabilities and the equation and solution of shared problems were the dimensions of a socio-educative intervention, markedly globalising. This scenario, as it is argued, was also, intentionally, one of transformation and of deliberate change of school and of the administration of the educative territoires.

  12. Chemical states of localized Fe atoms in ethylene matrices using in-beam Mössbauer spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Y., E-mail: kyoshio@pc.uec.ac.jp [University of Electro-Communications, Graduate School of Engineering Science (Japan); Yamada, Y. [Tokyo University of Science, Department of Chemistry (Japan); Tanigawa, S. [University of Electro-Communications, Graduate School of Engineering Science (Japan); Mihara, M. [Osaka University, Graduate School of Science (Japan); Kubo, M. K. [International Christian University, Division of Arts and Sciences (Japan); Sato, W. [Kanazawa University, Institute of Science and Engineering (Japan); Miyazaki, J. [Tokyo University of Agriculture and Technology, Department of Chemical Engineering (Japan); Nagatomo, T. [RIKEN, Nishina Center for Accelerator-Based Science (Japan); Sato, Y.; Natori, D.; Suzuki, M. [University of Electro-Communications, Graduate School of Engineering Science (Japan); Kobayashi, J. [International Christian University, Division of Arts and Sciences (Japan); Sato, S.; Kitagawa, A. [National Institute of Radiological Science (Japan)

    2016-12-15

    The reaction products of isolated single iron atoms in a low concentration matrix of ethylene were studied using in-beam Mössbauer spectroscopy with a short-lived {sup 57}Mn (T{sub 1/2}=1.45 m) beam. The in-beam Mössbauer spectrum of {sup 57}Fe arising from {sup 57}Mn in a matrix of ethylene and argon measured at 16 K was analyzed with four components. Density functional theory calculations were carried out to confirm the assignments. It was suggested that the reaction produced monoiron species of Fe(C {sub 2}H{sub 4}) with a spin state of S = 2.

  13. External Beam Radiotherapy for Clinically Localized Hormone-Refractory Prostate Cancer: Clinical Significance of Nadir Prostate-Specific Antigen Value Within 12 Months

    International Nuclear Information System (INIS)

    Ogawa, Kazuhiko; Nakamura, Katsumasa; Sasaki, Tomonari; Onishi, Hiroshi; Koizumi, Masahiko; Shioyama, Yoshiyuki; Araya, Masayuki; Mukumoto, Nobutaka M.S.; Mitsumori, Michihide; Teshima, Teruki

    2009-01-01

    Purpose: To analyze retrospectively the results of external beam radiotherapy for clinically localized hormone-refractory prostate cancer and investigate the clinical significance of nadir prostate-specific antigen (PSA) value within 12 months (nPSA12) as an early estimate of clinical outcomes after radiotherapy. Methods and Materials: Eighty-four patients with localized hormone-refractory prostate cancer treated with external beam radiotherapy were retrospectively reviewed. The total radiation doses ranged from 30 to 76 Gy (median, 66 Gy), and the median follow-up period for all 84 patients was 26.9 months (range, 2.7-77.3 months). Results: The 3-year actuarial overall survival, progression-free survival (PFS), and local control rates in all 84 patients after radiotherapy were 67%, 61%, and 93%, respectively. Although distant metastases and/or regional lymph node metastases developed in 34 patients (40%) after radiotherapy, local progression was observed in only 5 patients (6%). Of all 84 patients, the median nPSA12 in patients with clinical failure and in patients without clinical failure was 3.1 ng/mL and 0.5 ng/mL, respectively. When dividing patients according to low (<0.5 ng/mL) and high (≥0.5 ng/mL) nPSA12 levels, the 3-year PFS rate in patients with low nPSA12 and in those with high nPSA12 was 96% and 44%, respectively (p < 0.0001). In univariate analysis, nPSA12 and pretreatment PSA value had a significant impact on PFS, and in multivariate analysis nPSA12 alone was an independent prognostic factor for PFS after radiotherapy. Conclusions: External beam radiotherapy had an excellent local control rate for clinically localized hormone-refractory prostate cancer, and nPSA12 was predictive of clinical outcomes after radiotherapy.

  14. Recent progress in methods for non-invasive measurements of local strain in practical superconducting wires and conductors using quantum beam techniques

    International Nuclear Information System (INIS)

    Osamura, Kozo; Machiya, Shutaro; Tsuchiya, Yoshinori; Suzuki, Hiroshi; Awaji, Satoshi; Takahashi, Kohki; Oguro, Hidetoshi; Harjo, Stefanus; Hemmi, Tsutomu; Nakamoto, Tatsushi; Sugano, Michinaka; Jin, Xinzhe; Kajiwara, Kentaro

    2014-01-01

    Practical superconducting wires are designed with a composite structure to meet the desired engineering characteristics by expert selection of materials and design of the architecture. In practice, the local strain exerted on the superconducting component influences the electromagnetic properties. Here, recent progress in methods used to measure the local strain in practical superconducting wires and conductors using quantum beam techniques is introduced. Recent topics on the strain dependence of critical current are reviewed for three major practical wires: ITER-Nb 3 Sn strand, DI-BSCCO wires and REBCO tapes. (author)

  15. Impact of weight loss on survival after chemoradiation for locally advanced head and neck Cancer: secondary results of a randomized phase III trial (SAKK 10/94)

    International Nuclear Information System (INIS)

    Ghadjar, Pirus; Hayoz, Stefanie; Zimmermann, Frank; Bodis, Stephan; Kaul, David; Badakhshi, Harun; Bernier, Jacques; Studer, Gabriela; Plasswilm, Ludwig; Budach, Volker; Aebersold, Daniel M

    2015-01-01

    To analyze the impact of weight loss before and during chemoradiation on survival outcomes in patients with locally advanced head and neck cancer. From 07/1994-07/2000 a total of 224 patients with squamous cell carcinoma of the head and neck were randomized to either hyperfractionated radiation therapy alone or the same radiation therapy combined with two cycles of concomitant cisplatin. The primary endpoint was time to any treatment failure (TTF); secondary endpoints were locoregional recurrence-free survival (LRRFS), distant metastasis-free survival (DMFS) and overall survival (OS). Patient weight was measured 6 months before treatment, at treatment start and treatment end. The proportion of patients with >5% weight loss was 32% before, and 51% during treatment, and the proportion of patients with >10% weight loss was 12% before, and 17% during treatment. After a median follow-up of 9.5 years (range, 0.1 – 15.4 years) weight loss before treatment was associated with decreased TTF, LRRFS, DMFS, cancer specific survival and OS in a multivariable analysis. However, weight loss during treatment was not associated with survival outcomes. Weight loss before and during chemoradiation was commonly observed. Weight loss before but not during treatment was associated with worse survival

  16. Beam-Beam Effects

    International Nuclear Information System (INIS)

    Herr, W; Pieloni, T

    2014-01-01

    One of the most severe limitations in high-intensity particle colliders is the beam-beam interaction, i.e. the perturbation of the beams as they cross the opposing beams. This introduction to beam-beam effects concentrates on a description of the phenomena that are present in modern colliding beam facilities

  17. Adaptive-Predictive Organ Localization Using Cone-Beam Computed Tomography for Improved Accuracy in External Beam Radiotherapy for Bladder Cancer

    International Nuclear Information System (INIS)

    Lalondrelle, Susan; Huddart, Robert; Warren-Oseni, Karole; Hansen, Vibeke Nordmark; McNair, Helen; Thomas, Karen; Dearnaley, David; Horwich, Alan; Khoo, Vincent

    2011-01-01

    Purpose: To examine patterns of bladder wall motion during high-dose hypofractionated bladder radiotherapy and to validate a novel adaptive planning method, A-POLO, to prevent subsequent geographic miss. Methods and Materials: Patterns of individual bladder filling were obtained with repeat computed tomography planning scans at 0, 15, and 30 minutes after voiding. A series of patient-specific plans corresponding to these time-displacement points was created. Pretreatment cone-beam computed tomography was performed before each fraction and assessed retrospectively for adaptive intervention. In fractions that would have required intervention, the most appropriate plan was chosen from the patient's 'library,' and the resulting target coverage was reassessed with repeat cone-beam computed tomography. Results: A large variation in patterns of bladder filling and interfraction displacement was seen. During radiotherapy, predominant translations occurred cranially (maximum 2.5 cm) and anteriorly (maximum 1.75 cm). No apparent explanation was found for this variation using pretreatment patient factors. A need for adaptive planning was demonstrated by 51% of fractions, and 73% of fractions would have been delivered correctly using A-POLO. The adaptive strategy improved target coverage and was able to account for intrafraction motion also. Conclusions: Bladder volume variation will result in geographic miss in a high proportion of delivered bladder radiotherapy treatments. The A-POLO strategy can be used to correct for this and can be implemented from the first fraction of radiotherapy; thus, it is particularly suited to hypofractionated bladder radiotherapy regimens.

  18. Effect of beam expansion loss in a carbon nanotube-doped PVA film on passively mode-locked erbium-doped fiber lasers with different feedback ratios

    International Nuclear Information System (INIS)

    Cheng, Kuang-Nan; Chi, Yu-Chieh; Cheng, Chih-Hsien; Lin, Yung-Hsiang; Lo, Jui-Yung; Lin, Gong-Ru

    2014-01-01

    The effect of beam expansion induced divergent loss in a single-wall carbon nanotube (SWCNT) doped polyvinyl alcohol (PVA) based ultrafast saturable absorber (SA) film thickness on the passive mode-locking (PML) performances of erbium-doped fiber lasers are demonstrated. The variation on the PML pulsewidth of the EDFL is discussed by changing the SWCNT-PVA SA film thicknesses, together with adjusting the pumping power and the intra-cavity feedback ratio. An almost 6 dB increment of divergent loss when enlarging the SWCNT-PVA based SA film thickness from 30–130 µm is observed. When shrinking the SA thickness to 30 µm at the largest pumping power of 52.5 mW, the optical spectrum red-shifts to 1558.8 nm with its 3 dB spectral linewidth broadening up to 2.7 nm, while the pulse has already entered the soliton regime with multi-order Kelly sidebands aside the spectral shoulder. The soliton pulsewidth is as short as 790 fs, which is much shorter than those obtained with other thicker SWCNT doped PVA polymer film based SAs; therefore, the peak power from the output of the PML-EDFL is significantly enlarged accompanied by a completely suppressed residual continuous-wave level to achieve the largest on/off extinction ratio. The main mechanism of pulse shortening with reducing thickness of SWCNT doped PVA polymer film based SA is attributed to the limited beam expansion as well as the enlarged modulation depth, which results in shortened soliton pulsewidth with a clean dc background, and broadened spectrum with enriched Kelly sidebands. The increase of total SWCNT amount in the thicker SA inevitably causes a higher linear absorption; hence, the mode-locking threshold also rises accordingly. By enlarging pumping power from 38.5–52.5 mW, the highest ascent on pulse extinction of up to 32 dB is observed among all kinds of feedback conditions. Nevertheless, the enlargement on the extinction slightly decays with increasing the feedback ratio from 30–90

  19. 125I implants as an adjuvant to surgery and external beam radiotherapy in the management of locally advanced head and neck cancer

    International Nuclear Information System (INIS)

    Martinez, A.; Goffinet, D.R.; Fee, W.; Goode, R.; Cox, R.S.

    1983-01-01

    125 I seeds either individually placed or inserted into absorbable Vicryl suture carriers were utilized in conjunction with surgery and external beam radiotherapy in an attempt to increase local control rates in patients with advanced oropharyngeal and laryngopharyngeal cancers (T3-T4, N2-N3), massive cervical lymphadenopathy (N3) and an unknown primary site and locally recurrent head and neck cancers. Forty-eight patients were treated with 55 implants. The carotid artery was implanted in 15 patients, while seven patients had seeds inserted into the base of the skull region, and another three patients had implants near cranial nerves. Eighteen of the 48 patients were treated for cure. The actuarial survival at five years in this subgroup was 50%. The overall local control in the head and neck area was 58%. In this group no patients to date have had a local failure in the implanted volume. Seventeen patients with comparable stage of disease treated prior to 1974 with curative intent without 125 I implants were analyzed retrospectively for comparison with the implanted patients. The actuarial survival of these patients was 18% and the overall head and neck control was 21%. These differences are statistically significant at a P value of 0.01 and 0.007, respectively. Seventeen patients received implants for local recurrence. The local control in the head and neck area was 50%; however, the 2.5 year actuarial survival was only 17%. The complication rate was 11% (six of 55 implants). The improved survival, the high local control, and the minimal complication rates in this series makes the intraoperative implantation of 125 I seeds and effective adjunctive treatment to surgery and external beam irradiation

  20. Electron-beam-induced reduction of Fe3+ in iron phosphate dihydrate, ferrihydrite, haemosiderin and ferritin as revealed by electron energy-loss spectroscopy

    International Nuclear Information System (INIS)

    Pan, Ying-Hsi; Vaughan, Gareth; Brydson, Rik; Bleloch, Andrew; Gass, Mhairi; Sader, Kasim; Brown, Andy

    2010-01-01

    The effect of high-energy electron irradiation on ferritin/haemosiderin cores (in an iron-overloaded human liver biopsy), its mineral analogue; six-line ferrihydrite (6LFh), and iron phosphate dihydrate (which has similar octahedral ferric iron to oxygen coordination to that in ferrihydrite and ferritin/haemosiderin cores) has been investigated using electron energy-loss spectroscopy (EELS). Fe L 2,3 -ionisation edges were recorded on two types of electron microscope: a 200 keV transmission electron microscope (TEM) and a 100 keV scanning transmission electron microscope (STEM), in order to investigate the damage mechanisms in operation and to establish a methodology for minimum specimen alteration during analytical electron microscopic characterisation. A specimen damage mechanism dominated by radiolysis that results in the preferential loss of iron co-ordinating ligands (O, OH and H 2 O) is discussed. The net result of irradiation is structural re-organisation and reduction of iron within the iron hydroxides. At sufficiently low electron fluence and particularly in the lower incident energy, finer probe diameter STEM, the alteration is shown to be minimal. All the materials examined exhibit damage which as a function of cumulative fluence is best fitted by an inverse power-law, implying that several chemical and structural changes occur in response to the electron beam and we suggest that these are governed by secondary processes arising from the primary ionisation event. This work affirms that electron fluence and current density should be considered when measuring mixed valence ratios with EELS.

  1. RELAP5/MOD2. 5 analysis of the HFBR (High Flux Beam Reactor) for a loss of power and coolant accident

    Energy Technology Data Exchange (ETDEWEB)

    Slovik, G.C.; Rohatgi, U.S.; Jo, Jae.

    1990-05-01

    A set of postulated accidents were evaluated for the High Flux Beam Reactor (HFBR) at Brookhaven National Laboratory. A loss of power accident (LOPA) and a loss of coolant accident (LOCA) were analyzed. This work was performed in response to a DOE review that wanted to update the understanding of the thermal hydraulic behavior of the HFBR during these transients. These calculations were used to determine the margins to fuel damage at the 60 MW power level. The LOPA assumes all the backup power systems fail (although this event is highly unlikely). The reactor scrams, the depressurization valve opens, and the pumps coast down. The HFBR has down flow through the core during normal operation. To avoid fuel damage, the core normally goes through an extended period of forced down flow after a scram before natural circulation is allowed. During a LOPA, the core will go into flow reversal once the buoyancy forces are larger than the friction forces produced during the pump coast down. The flow will stagnate, reverse direction, and establish a buoyancy driven (natural circulation) flow around the core. Fuel damage would probably occur if the critical heat flux (CHF) limit is reached during the flow reversal event. The RELAP5/MOD2.5 code, with an option for heavy water, was used to model the HFBR and perform the LOPA calculation. The code was used to predict the time when the buoyancy forces overcome the friction forces and produce upward directed flow in the core. The Monde CHF correlation and experimental data taken for the HFBR during the design verification phase in 1963 were used to determine the fuel damage margin. 20 refs., 40 figs., 11 tabs.

  2. RELAP5/MOD2.5 analysis of the HFBR [High Flux Beam Reactor] for a loss of power and coolant accident

    International Nuclear Information System (INIS)

    Slovik, G.C.; Rohatgi, U.S.; Jo, Jae.

    1990-05-01

    A set of postulated accidents were evaluated for the High Flux Beam Reactor (HFBR) at Brookhaven National Laboratory. A loss of power accident (LOPA) and a loss of coolant accident (LOCA) were analyzed. This work was performed in response to a DOE review that wanted to update the understanding of the thermal hydraulic behavior of the HFBR during these transients. These calculations were used to determine the margins to fuel damage at the 60 MW power level. The LOPA assumes all the backup power systems fail (although this event is highly unlikely). The reactor scrams, the depressurization valve opens, and the pumps coast down. The HFBR has down flow through the core during normal operation. To avoid fuel damage, the core normally goes through an extended period of forced down flow after a scram before natural circulation is allowed. During a LOPA, the core will go into flow reversal once the buoyancy forces are larger than the friction forces produced during the pump coast down. The flow will stagnate, reverse direction, and establish a buoyancy driven (natural circulation) flow around the core. Fuel damage would probably occur if the critical heat flux (CHF) limit is reached during the flow reversal event. The RELAP5/MOD2.5 code, with an option for heavy water, was used to model the HFBR and perform the LOPA calculation. The code was used to predict the time when the buoyancy forces overcome the friction forces and produce upward directed flow in the core. The Monde CHF correlation and experimental data taken for the HFBR during the design verification phase in 1963 were used to determine the fuel damage margin. 20 refs., 40 figs., 11 tabs

  3. Electron-beam-induced reduction of Fe{sup 3+} in iron phosphate dihydrate, ferrihydrite, haemosiderin and ferritin as revealed by electron energy-loss spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Ying-Hsi; Vaughan, Gareth; Brydson, Rik [Institute for Materials Research, SPEME, University of Leeds, Leeds LS2 9JT (United Kingdom); Bleloch, Andrew; Gass, Mhairi [SuperSTEM, Daresbury Laboratories, Warrington WA4 4AD (United Kingdom); Sader, Kasim [Institute for Materials Research, SPEME, University of Leeds, Leeds LS2 9JT (United Kingdom); SuperSTEM, Daresbury Laboratories, Warrington WA4 4AD (United Kingdom); Brown, Andy, E-mail: a.p.brown@leeds.ac.uk [Institute for Materials Research, SPEME, University of Leeds, Leeds LS2 9JT (United Kingdom)

    2010-07-15

    The effect of high-energy electron irradiation on ferritin/haemosiderin cores (in an iron-overloaded human liver biopsy), its mineral analogue; six-line ferrihydrite (6LFh), and iron phosphate dihydrate (which has similar octahedral ferric iron to oxygen coordination to that in ferrihydrite and ferritin/haemosiderin cores) has been investigated using electron energy-loss spectroscopy (EELS). Fe L{sub 2,3}-ionisation edges were recorded on two types of electron microscope: a 200 keV transmission electron microscope (TEM) and a 100 keV scanning transmission electron microscope (STEM), in order to investigate the damage mechanisms in operation and to establish a methodology for minimum specimen alteration during analytical electron microscopic characterisation. A specimen damage mechanism dominated by radiolysis that results in the preferential loss of iron co-ordinating ligands (O, OH and H{sub 2}O) is discussed. The net result of irradiation is structural re-organisation and reduction of iron within the iron hydroxides. At sufficiently low electron fluence and particularly in the lower incident energy, finer probe diameter STEM, the alteration is shown to be minimal. All the materials examined exhibit damage which as a function of cumulative fluence is best fitted by an inverse power-law, implying that several chemical and structural changes occur in response to the electron beam and we suggest that these are governed by secondary processes arising from the primary ionisation event. This work affirms that electron fluence and current density should be considered when measuring mixed valence ratios with EELS.

  4. Mechanism of the nanoscale localization of Ge quantum dot nucleation on focused ion beam templated Si(001) surfaces

    International Nuclear Information System (INIS)

    Portavoce, A; Kammler, M; Hull, R; Reuter, M C; Ross, F M

    2006-01-01

    We investigate the fundamental mechanism by which self-assembled Ge islands can be nucleated at specific sites on Si(001) using ultra-low-dose focused ion beam (FIB) pre-patterning. Island nucleation is controlled by a nanotopography that forms after the implantation of Ga ions during subsequent thermal annealing of the substrate. This nanotopography evolves during the annealing stage, changing from a nanoscale annular depression associated with each focused ion beam spot to a nanoscale pit, and eventually disappearing (planarizing). The correspondence of Ge quantum dot nucleation sites to the focused ion beam features requires a growth surface upon which the nanotopography is preserved. A further key observation is that the Ge wetting layer thickness is reduced in patterned regions, allowing the formation of islands on the templated regions without nucleation elsewhere. These results provide routes to the greatly enhanced design and control of quantum dot distributions and dimensions

  5. Comparative sensitivities of functional MRI sequences in detection of local recurrence of prostate carcinoma after radical prostatectomy or external-beam radiotherapy.

    Science.gov (United States)

    Roy, Catherine; Foudi, Fatah; Charton, Jeanne; Jung, Michel; Lang, Hervé; Saussine, Christian; Jacqmin, Didier

    2013-04-01

    The aim of this retrospective study was to determine the respective accuracies of three types of functional MRI sequences-diffusion-weighted imaging (DWI), dynamic contrast-enhanced (DCE) MRI, and 3D (1)H-MR spectroscopy (MRS)-in the depiction of local prostate cancer recurrence after two different initial therapy options. From a cohort of 83 patients with suspicion of local recurrence based on prostate-specific antigen (PSA) kinetics who were imaged on a 3-T MRI unit using an identical protocol including the three functional sequences with an endorectal coil, we selected 60 patients (group A, 28 patients who underwent radical prostatectomy; group B, 32 patients who underwent external-beam radiation) who had local recurrence ascertained on the basis of a transrectal ultrasound-guided biopsy results and a reduction in PSA level after salvage therapy. All patients presented with a local relapse. Sensitivity with T2-weighted MRI and 3D (1)H-MRS sequences was 57% and 53%, respectively, for group A and 71% and 78%, respectively, for group B. DCE-MRI alone showed a sensitivity of 100% and 96%, respectively, for groups A and B. DWI alone had a higher sensitivity for group B (96%) than for group A (71%). The combination of T2-weighted imaging plus DWI plus DCE-MRI provided a sensitivity as high as 100% in group B. The performance of functional imaging sequences for detecting recurrence is different after radical prostatectomy and external-beam radiotherapy. DCE-MRI is a valid and efficient tool to detect prostate cancer recurrence in radical prostatectomy as well as in external-beam radiotherapy. The combination of DCE-MRI and DWI is highly efficient after radiation therapy. Three-dimensional (1)H-MRS needs to be improved. Even though it is not accurate enough, T2-weighted imaging remains essential for the morphologic analysis of the area.

  6. Evaluation of diagnostic accuracy of conventional and digital periapical radiography, panoramic radiography, and cone-beam computed tomography in the assessment of alveolar bone loss

    Science.gov (United States)

    Takeshita, Wilton Mitsunari; Vessoni Iwaki, Lilian Cristina; Da Silva, Mariliani Chicarelli; Tonin, Renata Hernandes

    2014-01-01

    Background: To evaluate the diagnostic accuracy of different radiographic methods in the assessment of proximal alveolar bone loss (ABL). Materials and Methods: ABL, the distance between cement-enamel junction and alveolar bone crest, was measured in 70 mandibular human teeth – directly on the mandibles (control), using conventional periapical radiography with film holders (Rinn XCP and Han-Shin), digital periapical radiography with complementary metal-oxide semiconductor sensor, conventional panoramic, and cone-beam computed tomography (CBCT). Three programs were used to measure ABL on the images: Image tool 3.0 (University of Texas Health Sciences Center, San Antonio, Texas, USA), Kodak Imaging 6.1 (Kodak Dental Imaging 6.1, Carestream Health®, Rochester, NY, USA), and i-CAT vision 1.6.20. Statistical analysis used ANOVA and Tukey's test at 5% significance level. Results: The tomographic images showed the highest means, whereas the lowest were found for periapical with Han-Shin. Controls differed from periapical with Han-Shin (P digital periapical (P = 0.0027). Conventional periapicals with film holders differed from each other (P = 0.0007). Digital periapical differed from conventional periapical with Han-Shin (P = 0.0004). Conclusions: Conventional periapical with Han-Shin film holder was the only method that differed from the controls. CBCT had the closest means to the controls. PMID:25191066

  7. Local deposition of high-purity Pt nanostructures by combining electron beam induced deposition and atomic layer deposition

    NARCIS (Netherlands)

    Mackus, A.J.M.; Mulders, J.J.L.; Sanden, van de M.C.M.; Kessels, W.M.M.

    2010-01-01

    An approach for direct-write fabrication of high-purity platinum nanostructures has been developed by combining nanoscale lateral patterning by electron beam induced deposition (EBID) with area-selective deposition of high quality material by atomic layer deposition (ALD). Because virtually pure,

  8. ACR Appropriateness Criteria for external beam radiation therapy treatment planning for clinically localized prostate cancer, part II of II

    Directory of Open Access Journals (Sweden)

    Nicholas G. Zaorsky, MD

    2017-07-01

    Conclusions: External beam radiation is a key component of the curative management of T1 and T2 prostate cancer. By combining the most recent medical literature, these Appropriateness Criteria can aid clinicians in determining the appropriate treatment delivery and personalized approaches for individual patients.

  9. Safe LHC beam commissioning

    International Nuclear Information System (INIS)

    Uythoven, J.; Schmidt, R.

    2007-01-01

    Due to the large amount of energy stored in magnets and beams, safety operation of the LHC is essential. The commissioning of the LHC machine protection system will be an integral part of the general LHC commissioning program. A brief overview of the LHC Machine Protection System will be given, identifying the main components: the Beam Interlock System, the Beam Dumping System, the Collimation System, the Beam Loss Monitoring System and the Quench Protection System. An outline is given of the commissioning strategy of these systems during the different commissioning phases of the LHC: without beam, injection and the different phases with stored beam depending on beam intensity and energy. (author)

  10. Beam-loss induced pressure rise of Large Hadron Collider collimator materials irradiated with 158  GeV/u In^{49+} ions at the CERN Super Proton Synchrotron

    Directory of Open Access Journals (Sweden)

    E. Mahner

    2004-10-01

    Full Text Available During heavy ion operation, large pressure rises, up to a few orders of magnitude, were observed at CERN, GSI, and BNL. The dynamic pressure rises were triggered by lost beam ions that impacted onto the vacuum chamber walls and desorbed about 10^{4} to 10^{7} molecules per ion. The deterioration of the dynamic vacuum conditions can enhance charge-exchange beam losses and can lead to beam instabilities or even to beam abortion triggered by vacuum interlocks. Consequently, a dedicated measurement of heavy-ion induced molecular desorption in the GeV/u energy range is important for Large Hadron Collider (LHC ion operation. In 2003, a desorption experiment was installed at the Super Proton Synchrotron to measure the beam-loss induced pressure rise of potential LHC collimator materials. Samples of bare graphite, sputter coated (Cu, TiZrV graphite, and 316 LN (low carbon with nitrogen stainless steel were irradiated under grazing angle with 158  GeV/u indium ions. After a description of the new experimental setup, the results of the pressure rise measurements are presented, and the derived desorption yields are compared with data from other experiments.

  11. Hearing loss due to concurrent daily low-dose cisplatin chemoradiation for locally advanced head and neck cancer

    International Nuclear Information System (INIS)

    Zuur, Charlotte L.; Simis, Yvonne J.W.; Verkaik, Roxanna S.; Schornagel, Jan H.; Balm, Alfons J.M.; Dreschler, Wouter A.; Rasch, Coen R.N.

    2008-01-01

    Background and purpose: Cisplatin-based chemo-irradiation (CRT) is increasingly used for head and neck squamous cell carcinoma (HNSCC). We aimed to assess hearing deterioration due to low-dose cisplatin chemoradiation and to compare the observed hearing loss with hearing loss in our previously described high-dose cisplatin CRT cohort. Materials and methods: A prospective analysis of hearing thresholds at low and (ultra)-high frequencies obtained before and after treatment in 60 patients. Patients received low-dose cisplatin (6 mg/m 2 , daily infusions, 20-25 days) with concomitant accelerated radiotherapy (70 Gy). Results: Audiometry up to 16 kHz was performed before therapy and 31 days (median) post-treatment. The total incidence of ototoxicity in CTCAEv3.0 was 31% in audiograms up to 8 kHz, and 5% of ears tested qualified for HAs due to treatment. The mean hearing loss at speech frequencies was 2.6 dB (SD 5.7) and 2.3 dB (SD 9.2) at PTA 1-2-4 kHz air-conduction and bone-conduction, respectively. The mean hearing loss at ultra-high frequencies (PTA AC 8-10-12.5 kHz) was 9.0 dB (SD 8.1). Low-dose cisplatin CRT caused less acute hearing loss (CTCAE 31%), compared to high-dose cisplatin CRT (CTCAE 78%). Conclusions: Low-dose cisplatin chemo-irradiation for HNSCC is a relatively safe treatment protocol with respect to ototoxicity

  12. Dynamic change of global and local information processing in propofol-induced loss and recovery of consciousness.

    Directory of Open Access Journals (Sweden)

    Martin M Monti

    Full Text Available Whether unique to humans or not, consciousness is a central aspect of our experience of the world. The neural fingerprint of this experience, however, remains one of the least understood aspects of the human brain. In this paper we employ graph-theoretic measures and support vector machine classification to assess, in 12 healthy volunteers, the dynamic reconfiguration of functional connectivity during wakefulness, propofol-induced sedation and loss of consciousness, and the recovery of wakefulness. Our main findings, based on resting-state fMRI, are three-fold. First, we find that propofol-induced anesthesia does not bear differently on long-range versus short-range connections. Second, our multi-stage design dissociated an initial phase of thalamo-cortical and cortico-cortical hyperconnectivity, present during sedation, from a phase of cortico-cortical hypoconnectivity, apparent during loss of consciousness. Finally, we show that while clustering is increased during loss of consciousness, as recently suggested, it also remains significantly elevated during wakefulness recovery. Conversely, the characteristic path length of brain networks (i.e., the average functional distance between any two regions of the brain appears significantly increased only during loss of consciousness, marking a decrease of global information-processing efficiency uniquely associated with unconsciousness. These findings suggest that propofol-induced loss of consciousness is mainly tied to cortico-cortical and not thalamo-cortical mechanisms, and that decreased efficiency of information flow is the main feature differentiating the conscious from the unconscious brain.

  13. Clinicohistopathological correlations in juvenile localized scleroderma: studies on a subset of children with hypopigmented juvenile localized scleroderma due to loss of epidermal melanocytes.

    Science.gov (United States)

    Sung, Joanne J; Chen, Tina S; Gilliam, Anita C; McCalmont, Timothy H; Gilliam, Amy E

    2011-08-01

    Localized scleroderma or morphea is a connective tissue disorder characterized by fibrosis of the skin and subcutaneous tissue. Excessive accumulation of collagen underlies the fibrosis, yet the pathogenesis is unknown. A subset of localized scleroderma/morphea, juvenile localized scleroderma (JLS), affects children and adolescents. The clinical and microscopic features of JLS have not been fully characterized. The goal is to better characterize the microscopic features of JLS. We collected a distinctive data set of 35 children with JLS, 19 (54%) of whom presented with hypopigmented lesions, and performed a retrospective chart and pathology review. We had adequate tissue for immunostaining studies on 8 of these individuals. We found that: (1) CD34 and factor XIIIa immunostaining, reported previously in adult morphea and scleroderma, when used with clinical information, is valuable for confirming a diagnosis of JLS; and (2) presence of hypopigmented lesions in JLS correlates with immunostaining studies. Decreased numbers of MelanA(+) melanocytes were present at the dermoepidermal junction in lesional skin in two of 3 children with hypopigmented JLS and in two of 4 children with nonhypopigmented JLS. The number of cases is small, a function of the small number of children who have biopsy specimens with material sufficient for multiple immunostaining procedures. These results provide a useful immunostaining method for confirmation of the diagnosis of JLS. They suggest a complex autoimmune phenotype in some children with JLS. Copyright © 2010 American Academy of Dermatology, Inc. Published by Mosby, Inc. All rights reserved.

  14. Localization of a Portion of an Endorectal Balloon for Prostate Image-Guided Radiation Therapy Using Cone-Beam Tomosynthesis: A Feasibility Study

    Energy Technology Data Exchange (ETDEWEB)

    Ng, Sook Kien, E-mail: Sook_Ng@dfci.harvard.edu [Department of Radiation Oncology, Brigham and Women' s Hospital and Harvard Medical School, Boston, MA (United States); Department of Radiation Oncology, Mannheim Medical Centre, University of Heidelberg, Mannheim (Germany); Zygmanski, Piotr; Lyatskaya, Yulia; D' Amico, Anthony V.; Cormack, Robert A. [Department of Radiation Oncology, Brigham and Women' s Hospital and Harvard Medical School, Boston, MA (United States)

    2012-06-01

    Purpose: To assess the feasibility of using cone-beam tomosynthesis (CBTS) to localize the air-tissue interface for the application of prostate image-guided radiation therapy using an endorectal balloon for immobilization and localization. Methods and Materials: A Feldkamp-David-Kress-based CBTS reconstruction was applied to selected sets of cone-beam computed tomography (CBCT) projection data to simulate volumetric imaging achievable from tomosynthesis for a limited range of scan angles. Projection data were calculated from planning CT images of 10 prostate cancer patients treated with an endorectal balloon, as were experimental CBCT projections for a pelvic phantom in two patients. More than 50 points at the air-tissue interface were objectively identified by an intensity-based interface-finding algorithm. Using three-dimensional point sets extracted from CBTS images compared with points extracted from corresponding CBCT images, the relative shift resulting from a reduced scan angle was determined. Because the CBCT and CBTS images were generated from the same projection data set, shift identified was presumed to be due to distortions introduced by the tomosynthesis technique. Results: Scans of {>=}60 Degree-Sign were shown to be able to localize an air-tissue interface near the isocenter with accuracy on the order of a millimeter. The accuracy was quantified in terms of the mean discrepancy as a function of reconstruction angle. Conclusion: This work provides an understanding of the effect of scan angle used in localization of a portion of an endorectal balloon by means of CBTS. CBTS with relatively small scan angles is capable of accurately localizing an extended interface near the isocenter and may provide clinically relevant measurements to guide IGRT treatments while reducing imaging radiation to the patient.

  15. Localization of a Portion of an Endorectal Balloon for Prostate Image-Guided Radiation Therapy Using Cone-Beam Tomosynthesis: A Feasibility Study

    International Nuclear Information System (INIS)

    Ng, Sook Kien; Zygmanski, Piotr; Lyatskaya, Yulia; D’Amico, Anthony V.; Cormack, Robert A.

    2012-01-01

    Purpose: To assess the feasibility of using cone-beam tomosynthesis (CBTS) to localize the air–tissue interface for the application of prostate image-guided radiation therapy using an endorectal balloon for immobilization and localization. Methods and Materials: A Feldkamp-David-Kress-based CBTS reconstruction was applied to selected sets of cone-beam computed tomography (CBCT) projection data to simulate volumetric imaging achievable from tomosynthesis for a limited range of scan angles. Projection data were calculated from planning CT images of 10 prostate cancer patients treated with an endorectal balloon, as were experimental CBCT projections for a pelvic phantom in two patients. More than 50 points at the air–tissue interface were objectively identified by an intensity-based interface-finding algorithm. Using three-dimensional point sets extracted from CBTS images compared with points extracted from corresponding CBCT images, the relative shift resulting from a reduced scan angle was determined. Because the CBCT and CBTS images were generated from the same projection data set, shift identified was presumed to be due to distortions introduced by the tomosynthesis technique. Results: Scans of ≥60° were shown to be able to localize an air–tissue interface near the isocenter with accuracy on the order of a millimeter. The accuracy was quantified in terms of the mean discrepancy as a function of reconstruction angle. Conclusion: This work provides an understanding of the effect of scan angle used in localization of a portion of an endorectal balloon by means of CBTS. CBTS with relatively small scan angles is capable of accurately localizing an extended interface near the isocenter and may provide clinically relevant measurements to guide IGRT treatments while reducing imaging radiation to the patient.

  16. Beam cleaning of the incoming beam in experimental IRs in HL-LHC

    CERN Document Server

    Garcia Morales, Hector; Redaelli, Stefano; De Maria, Riccardo; CERN. Geneva. ATS Department

    2017-01-01

    The HL-LHC will store 675 MJ of energy per beam, about 300 MJ more than the nominal LHC. Due to the increase in stored energy and a different interaction region (IR) layout and optics design, the collimation system for the incoming beam must be revisited in order to avoid dangerous losses that could cause quenches and machine damage. This paper studies the effectiveness of the current LHC collimation system in intercepting cleaning losses close to the experiments in the HL-LHC. The study reveals that in addition to the triplet also the Q4 needs local protection, which could be provided by an additional pair of TCTs.

  17. Local secondary-electron emission spectra of graphite and gold surfaces obtained using the Scanning Probe Energy Loss Spectrometer (SPELS)

    International Nuclear Information System (INIS)

    Lawton, J J; Pulisciano, A; Palmer, R E

    2009-01-01

    Secondary-electron emission (SEE) spectra have been obtained with the Scanning Probe Energy Loss Spectrometer at a tip-sample distance of only 50 nm. Such short working distances are required for the best theoretical spatial resolution (<10 nm). The SEE spectra of graphite, obtained as a function of tip bias voltage, are shown to correspond to unoccupied states in the electronic band structure. The SEE spectra of thin gold films demonstrate the capability of identifying (carbonaceous) surface contamination with this technique.

  18. Local secondary-electron emission spectra of graphite and gold surfaces obtained using the Scanning Probe Energy Loss Spectrometer (SPELS)

    Energy Technology Data Exchange (ETDEWEB)

    Lawton, J J; Pulisciano, A; Palmer, R E, E-mail: R.E.Palmer@bham.ac.u [Nanoscale Physics Research Laboratory, School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT (United Kingdom)

    2009-11-25

    Secondary-electron emission (SEE) spectra have been obtained with the Scanning Probe Energy Loss Spectrometer at a tip-sample distance of only 50 nm. Such short working distances are required for the best theoretical spatial resolution (<10 nm). The SEE spectra of graphite, obtained as a function of tip bias voltage, are shown to correspond to unoccupied states in the electronic band structure. The SEE spectra of thin gold films demonstrate the capability of identifying (carbonaceous) surface contamination with this technique.

  19. Investigation of some locally water-soluble natural polymers as circulation loss control agents during oil fields drilling

    Directory of Open Access Journals (Sweden)

    A.M. Alsabagh

    2014-03-01

    Full Text Available Eliminating or controlling lost circulation during drilling process is costly and time-consuming. Polymers play an important role in mud loss control for their viscosity due to their high molecular weight. In this paper, three natural cellulosic polymers (carboxymethyl cellulose, guar gum and potato starch were investigated as lost circulation control material by measuring different filtration parameters such as; spurt loss, fluid loss and permeability plugging tester value according to the American Petroleum Institute (API standard. The experiments were conducted in a permeability plugging apparatus (PPA at a differential pressure of 100 and 300 psi, using 10, 60 and 90 ceramic discs. From the obtained data, it was found that the 0.1% from the carboxymethyl cellulose exhibited the best results in the filtration parameters among 0.3% guar gum and 0.6% potato starch. At the same time the carboxymethyl cellulose (CMC enhanced the rheological properties of the drilling mud better than the two other used natural polymers in the term of gel strength, thixotropy, plastic and apparent viscosity. These results were discussed in the light of the adsorption and micellar formation.

  20. Evaluation of diagnostic accuracy of conventional and digital periapical radiography, panoramic radiography, and cone-beam computed tomography in the assessment of alveolar bone loss

    Directory of Open Access Journals (Sweden)

    Wilton Mitsunari Takeshita

    2014-01-01

    Full Text Available Background: To evaluate the diagnostic accuracy of different radiographic methods in the assessment of proximal alveolar bone loss (ABL. Materials and Methods: ABL, the distance between cement-enamel junction and alveolar bone crest, was measured in 70 mandibular human teeth - directly on the mandibles (control, using conventional periapical radiography with film holders (Rinn XCP and Han-Shin, digital periapical radiography with complementary metal-oxide semiconductor sensor, conventional panoramic, and cone-beam computed tomography (CBCT. Three programs were used to measure ABL on the images: Image tool 3.0 (University of Texas Health Sciences Center, San Antonio, Texas, USA, Kodak Imaging 6.1 (Kodak Dental Imaging 6.1, Carestream Health ® , Rochester, NY, USA, and i-CAT vision 1.6.20. Statistical analysis used ANOVA and Tukey′s test at 5% significance level. Results: The tomographic images showed the highest means, whereas the lowest were found for periapical with Han-Shin. Controls differed from periapical with Han-Shin (P < 0.0001. CBCT differed from panoramic (P = 0.0130, periapical with Rinn XCP (P = 0.0066, periapical with Han-Shin (P < 0.0001, and digital periapical (P = 0.0027. Conventional periapicals with film holders differed from each other (P = 0.0007. Digital periapical differed from conventional periapical with Han-Shin (P = 0.0004. Conclusions: Conventional periapical with Han-Shin film holder was the only method that differed from the controls. CBCT had the closest means to the controls.

  1. Remote sensing of local structure of the quasi-perpendicular Earth's bow shock by using field-aligned beams

    Directory of Open Access Journals (Sweden)

    B. Miao

    2009-03-01

    Full Text Available Field-aligned ion beams (FABs originate at the quasi-perpendicular Earth's bow shock and constitute an important ion population in the foreshock region. The bulk velocity of these FABs depends significantly on the shock normal angle, which is the angle between shock normal and upstream interplanetary magnetic field (IMF. This dependency may therefore be taken as an indicator of the local structure of the shock. Applying the direct reflection model to Cluster measurements, we have developed a method that uses proton FABs in the foreshock region for remote sensing of the local shock structure. The comparison of the model results with the multi-spacecraft observations of FAB events shows very good agreement in terms of wave amplitude and frequency of surface waves at the shock front.

  2. Analysis of an accident of local zone control system of 'pressure loss in the compartment water supply reservoir'

    International Nuclear Information System (INIS)

    Catana, A.

    2001-01-01

    This work presents the aftermath of a failure in the Zonal Control System caused by an accident of 'pressure loss in the compartment water supply reservoir' leading to an operational function fault of the liquid zonal control system. Causes for pressure drop may be several, as for instance: simultaneous mechanical fault of the three pumps, class IV total loss of power, a crack of reservoir, etc. Should this accident happens the reactor is shut down automatically by the digital control computer, on the 'ZONE CONTROL SYSTEM FAILURE' setback condition. The analyses were done hypothesizing that the covering gas system is functioning at design parameters and that the only possible accident is the one of pressure loss in supply reservoir. By making use of the software system developed at INR Pitesti, we could make the analysis of the phenomena which take place and thus we could obtain the evolution of the main parameters, namely, neutron and thermohydraulic parameters, as well as the actuating mode of the control and safety systems. Thus, by assuming a pressure drop under 8. 27 bar the 'SETBACK' system is triggered with a final value of the neutron power of 2% FP which can be reached with a power variation rate of 0.00086 decade/sec (- 0.1%/sec). In conclusion, the main parameters evolve as follows: 1. the water level in compartments is 'frozen' at a level at which the pressure in the supply reservoir is 7.3 bar; 2. the mechanical rods are gradually inserted, one bank first and a second one if necessary; 3. the shim rods are fully inserted; 4. the systems of SDS1 and SDS2 scram systems remain unactuated; 5. after 10 minutes from the 'SETBACK' triggering, the neutron power is reduced under 4%; 6. the thermohydraulic parameters of the primary circuit are maintained at normal values; 7. the thermohydraulic parameters of the secondary circuit are maintained at normal values

  3. Refinement of Treatment Setup and Target Localization Accuracy Using Three-Dimensional Cone-Beam Computed Tomography for Stereotactic Body Radiotherapy

    International Nuclear Information System (INIS)

    Wang Zhiheng; Nelson, John W.; Yoo, Sua; Wu, Q. Jackie; Kirkpatrick, John P.; Marks, Lawrence B.; Yin Fangfang

    2009-01-01

    Purposes: To quantitatively compare two-dimensional (2D) orthogonal kV with three-dimensional (3D) cone-beam CT (CBCT) for target localization; and to assess intrafraction motion with kV images in patients undergoing stereotactic body radiotherapy (SBRT). Methods and Materials: A total of 50 patients with 58 lesions received 178 fractions of SBRT. After clinical setup using in-room lasers and skin/cradle marks placed at simulation, patients were imaged and repositioned according to orthogonal kV/MV registration of bony landmarks to digitally reconstructed radiographs from the planning CT. A subsequent CBCT was registered to the planning CT using soft tissue information, and the resultant 'residual error' was measured and corrected before treatment. Posttreatment 2D kV and/or 3D CBCT images were compared with pretreatment images to determine any intrafractional position changes. Absolute averages, statistical means, standard deviations, and root mean square (RMS) values of observed setup error were calculated. Results: After initial setup to external marks with laser guidance, 2D kV images revealed vector mean setup deviations of 0.67 cm (RMS). Cone-beam CT detected residual setup deviations of 0.41 cm (RMS). Posttreatment imaging demonstrated intrafractional variations of 0.15 cm (RMS). The individual shifts in three standard orthogonal planes showed no obvious directional biases. Conclusions: After localization based on superficial markings in patients undergoing SBRT, orthogonal kV imaging detects setup variations of approximately 3 to 4 mm in each direction. Cone-beam CT detects residual setup variations of approximately 2 to 3 mm

  4. Loss of p53 promotes anaplasia and local invasion in ret/PTC1-induced thyroid carcinomas.

    Science.gov (United States)

    La Perle, K M; Jhiang, S M; Capen, C C

    2000-08-01

    Papillary thyroid carcinomas in humans are associated with the ret/PTC oncogene and, following loss of p53 function, may progress to anaplastic carcinomas. Mice with thyroid-targeted expression of ret/PTC1 developed papillary thyroid carcinomas that were minimally invasive and did not metastasize. These mice were crossed with p53-/- mice to investigate whether loss of p53 would promote anaplasia and metastasis of ret/PTC1-induced thyroid tumors. The majority of p53-/- mice died or were euthanized by 17 weeks of age due to the development of thymic lymphomas, soft tissue sarcomas, and testicular teratomas. All ret/PTC1 mice developed thyroid carcinomas, but tumors in p53-/- mice were more anaplastic, larger in diameter, more invasive, and had a higher mitotic index than tumors in p53+/+ and p53+/- mice. Thyroid tumors did not metastasize in any of the experimental p53+/+ and p53+/- mice anaplasia and invasiveness of thyroid carcinomas.

  5. Thalamocortical neuron loss and localized astrocytosis in the Cln3Deltaex7/8 knock-in mouse model of Batten disease.

    Science.gov (United States)

    Pontikis, Charlie C; Cotman, Susan L; MacDonald, Marcy E; Cooper, Jonathan D

    2005-12-01

    Juvenile neuronal ceroid lipofuscinosis (JNCL) is the result of mutations in the Cln3 gene. The Cln3 knock-in mouse (Cln3Deltaex7/8) reproduces the most common Cln3 mutation and we have now characterized the CNS of these mice at 12 months of age. With the exception of the thalamus, Cln3Deltaex7/8 homozygotes displayed no significant regional atrophy, but a range of changes in individual laminar thickness that resulted in variable cortical thinning across subfields. Stereological analysis revealed a pronounced loss of neurons within individual laminae of somatosensory cortex of affected mice and the novel finding of a loss of sensory relay thalamic neurons. These affected mice also exhibited profound astrocytic reactions that were most pronounced in the neocortex and thalamus, but diminished in other brain regions. These data provide the first direct evidence for neurodegenerative and reactive changes in the thalamocortical system in JNCL and emphasize the localized nature of these events.

  6. Electron-beam induced amorphization of stishovite: Silicon-coordination change observed using Si K-edge extended electron energy-loss fine structure

    International Nuclear Information System (INIS)

    Aken, P.A. van; Sharp, T.G.; Seifert, F.

    1998-01-01

    The analysis of the extended energy-loss fine structure (EXELFS) of the Si K-edge for sixfold-coordinated Si in synthetic stishovite and fourfold-coordinated Si in natural α-quartz is reported by using electron energy-loss spectroscopy (EELS) in combination with transmission electron microscopy (TEM). The stishovite Si K-edge EXELFS spectra were measured as a time-dependent series to document irradiation-induced amorphization. The amorphization was also investigated through the change in Si K- and O K-edge energy-loss near edge structure (ELNES). For α-quartz, in contrast to stishovite, electron irradiation-induced vitrification, produced no detectable changes of the EXELFS. The Si K-edge EXELFS were analysed with the classical extended X-ray absorption fine structure (EXAFS) treatment and compared to ab initio curve-waved multiple-scattering (MS) calculations of EXAFS spectra for stishovite and α-quartz. Highly accurate information on the local atomic environment of the silicon atoms during the irradiation-induced amorphization of stishovite is obtained from the EXELFS structure parameters The mean Si-O bond distance R and mean Si coordination number N changes from R=0.1775 nm and N=6 for stishovite through a disordered intermediate state (R∼0.172 nm and N∼5) to R∼0.167 nm and N∼4.5 for a nearly amorphous state similar to α-quartz (R=0.1609 nm and N=4). During the amorphization process, the Debye-Waller factor (DWF) passes through a maximum value of σ N 2 ∼83.8pm 2 as it changes from σ st 2 =51.8pm 2 for sixfold to σ qu 2 =18.4pm 2 for fourfold coordination of Si. This increase in Debye-Waller factor indicates an increase in mean-square relative displacement (MSRD) between the central silicon atom and its oxygen neighbours. Using the EXELFS data for amorphization, a new method is developed to derive the relative amounts of Si coordinations in high-pressure minerals with mixed coordination. For the radiation-induced amorphization process of

  7. Electron-beam induced amorphization of stishovite: Silicon-coordination change observed using Si K-edge extended electron energy-loss fine structure

    Science.gov (United States)

    van Aken, P. A.; Sharp, T. G.; Seifert, F.

    The analysis of the extended energy-loss fine structure (EXELFS) of the Si K-edge for sixfold-coordinated Si in synthetic stishovite and fourfold-coordinated Si in natural α-quartz is reported by using electron energy-loss spectroscopy (EELS) in combination with transmission electron microscopy (TEM). The stishovite Si K-edge EXELFS spectra were measured as a time-dependent series to document irradiation-induced amorphization. The amorphization was also investigated through the change in Si K- and O K-edge energy-loss near edge structure (ELNES). For α-quartz, in contrast to stishovite, electron irradiation-induced vitrification, verified by selected area electron diffraction (SAED), produced no detectable changes of the EXELFS. The Si K-edge EXELFS were analysed with the classical extended X-ray absorption fine structure (EXAFS) treatment and compared to ab initio curve-waved multiple-scattering (MS) calculations of EXAFS spectra for stishovite and α-quartz. Highly accurate information on the local atomic environment of the silicon atoms during the irradiation-induced amorphization of stishovite is obtained from the EXELFS structure parameters (Si-O bond distances, coordination numbers and Debye-Waller factors). The mean Si-O bond distance R and mean Si coordination number N changes from R=0.1775 nm and N=6 for stishovite through a disordered intermediate state (R 0.172 nm and N 5) to R 0.167 nm and N 4.5 for a nearly amorphous state similar to α-quartz (R=0.1609 nm and N=4). During the amorphization process, the Debye-Waller factor (DWF) passes through a maximum value of as it changes from for sixfold to for fourfold coordination of Si. This increase in Debye-Waller factor indicates an increase in mean-square relative displacement (MSRD) between the central silicon atom and its oxygen neighbours that is consistent with the presence of an intermediate structural state with fivefold coordination of Si. The distribution of coordination states can be estimated by

  8. Correlation between local glaucomatous visual field defects and loss of nerve fiber layer thickness measured with polarimetry and spectral domain OCT.

    Science.gov (United States)

    Horn, Folkert K; Mardin, Christian Y; Laemmer, Robert; Baleanu, Delia; Juenemann, Anselm M; Kruse, Friedrich E; Tornow, Ralf P

    2009-05-01

    To study the correlation between local perimetric field defects and glaucoma-induced thickness reduction of the nerve layer measured in the peripapillary area with scanning laser polarimetry (SLP) and spectral domain optical coherence tomography (SOCT) and to compare the results with those of a theoretical model. The thickness of the retinal nerve fiber layer was determined in 32 sectors (11.25 degrees each) by using SLP with variable cornea compensation (GDxVCC; Laser Diagnostics, San Diego, CA) and the newly introduced high-resolution SOCT (Spectralis; Heidelberg Engineering, Heidelberg, Germany). Eighty-eight healthy subjects served as control subjects, to determine the thickness deviation in patients with glaucoma. The relationship between glaucomatous nerve fiber reduction and visual field losses was calculated in six nerve fiber bundle-related areas. Sixty-four patients at different stages of open-angle glaucoma and 26 patients with ocular hypertension underwent perimetry (Octopus G1; Haag-Streit, Köniz, Switzerland) and measurements with the two morphometric techniques. Sector-shaped analyses between local perimetric losses and reduction of the retinal nerve fiber layer thickness showed a significant association for corresponding areas except for the central visual field in SLP. Correlation coefficients were highest in the area of the nasal inferior visual field (SOCT, -0.81; SLP, -0.57). A linear model describes the association between structural and functional damage. Localized perimetric defects can be explained by reduced nerve fiber layer thickness. The data indicate that the present SOCT is useful for determining the functional-structural relationship in peripapillary areas and that association between perimetric defects and corresponding nerve fiber losses is stronger for SOCT than for the present SLP. (ClinicalTrials.gov number, NCT00494923.).

  9. Active control of annular flow-induced vibration of axisymmetric elastic beam by the local gap width control

    International Nuclear Information System (INIS)

    Takada, Shoji; Shintani, Atsuhiko; Ito, Tomohiro; Fujita, Katsuhisa

    2011-01-01

    Flow-induced vibration may occur in the structures such as elastic beams subjected to annular flow in the narrow passage. Once the flow-induced vibration occurs, vibration amplitude becomes larger, consequently it causes a lot of troubles such as fatigue or failure in mechanical structures. In this paper, for the purpose to avoid these troubles, the active control of vibration of an axisymmetric elastic beam subjected to annular flow is investigated. An air-pressured actuator is attached on the surface of the circular cylinder for the vibrational control. As the shape of the actuator changes by control, the gap width in narrow passage changes, which causes the change of the fluid pressure. Therefore, the vibration of the fluid-structure coupled system can be suppressed. The fluid-structure coupled equation based on the Euler-Bernoulli type of partial differential equation and the Navier-Stokes equations is analytically derived including control terms. By applying the optimal control law to the coupled system, the unstable behavior is stabilized. The stability of the coupled system is investigated by eigenvalue analyses of controlled coupled equations. Numerical simulations are performed to investigate the efficiency of the proposed control method. (author)

  10. Observations of beam-beam effects in the LHC 2011

    International Nuclear Information System (INIS)

    Herr, W.; Alemany, R.; Buffat, X.; Calaga, R.; Giachino, R.; Papotti, G.; Pieloni, T.; Trad, G.; Schaumann, M.

    2012-01-01

    We have reported on the first studies of beam-beam effects in the LHC with high intensity, high brightness beams and can summarize the results as follows. The effect of the beam-beam interaction on the beam dynamics is clearly established. The LHC allows very large head-on tune shifts above nominal. The effect of long range interactions on the beam lifetime and losses (dynamic aperture) is clearly visible. The number of head-on and/or long range interactions important for losses and all predicted PACMAN effects have been observed. All observations are in good agreement with the expectations

  11. Processamento temporal, localização e fechamento auditivo em portadores de perda auditiva unilateral Temporal processing, localization and auditory closure in individuals with unilateral hearing loss

    Directory of Open Access Journals (Sweden)

    Regiane Nishihata

    2012-01-01

    , sound localization, and auditory closure, and to investigate possible associations with complaints of learning, communication and language difficulties in individuals with unilateral hearing loss. METHODS: Participants were 26 individuals with ages between 8 and 15 years, divided into two groups: Unilateral hearing loss group; and Normal hearing group. Each group was composed of 13 individuals, matched by gender, age and educational level. All subjects were submitted to anamnesis, peripheral hearing evaluation, and auditory processing evaluation through behavioral tests of sound localization, sequential memory, Random Detection Gap test, and speech-in-noise test. Nonparametric statistical tests were used to compare the groups, considering the presence or absence of hearing loss and the ear with hearing loss. RESULTS: Unilateral hearing loss started during preschool, and had unknown or identified etiologies, such as meningitis, traumas or mumps. Most individuals reported delays in speech, language and learning developments, especially those with hearing loss in the right ear. The group with hearing loss had worse responses in the abilities of temporal ordering and resolution, sound localization and auditory closure. Individuals with hearing loss in the left ear showed worse results than those with hearing loss in the right ear in all abilities, except in sound localization. CONCLUSION: The presence of unilateral hearing loss causes sound localization, auditory closure, temporal ordering and temporal resolution difficulties. Individuals with unilateral hearing loss in the right ear have more complaints than those with unilateral hearing loss in the left ear. Individuals with hearing loss in the left ear have more difficulties in auditory closure, temporal resolution, and temporal ordering.

  12. IMPACT simulation and the SNS linac beam

    International Nuclear Information System (INIS)

    Zhang, Y.; Qiang, J.

    2008-01-01

    Multi-particle tracking simulations for the SNS linac beam dynamics studies are performed with the IMPACT code. Beam measurement results are compared with the computer simulations, including beam longitudinal halo and beam losses in the superconducting linac, transverse beam Courant-Snyder parameters and the longitudinal beam emittance in the linac. In most cases, the simulations show good agreement with the measured results

  13. Loss of Local Astrocyte Support Disrupts Action Potential Propagation and Glutamate Release Synchrony from Unmyelinated Hippocampal Axon Terminals In Vitro.

    Science.gov (United States)

    Sobieski, Courtney; Jiang, Xiaoping; Crawford, Devon C; Mennerick, Steven

    2015-08-05

    Neuron-astrocyte interactions are critical for proper CNS development and function. Astrocytes secrete factors that are pivotal for synaptic development and function, neuronal metabolism, and neuronal survival. Our understanding of this relationship, however, remains incomplete due to technical hurdles that have prevented the removal of astrocytes from neuronal circuits without changing other important conditions. Here we overcame this obstacle by growing solitary rat hippocampal neurons on microcultures that were comprised of either an astrocyte bed (+astrocyte) or a collagen bed (-astrocyte) within the same culture dish. -Astrocyte autaptic evoked EPSCs, but not IPSCs, displayed an altered temporal profile, which included increased synaptic delay, increased time to peak, and severe glutamate release asynchrony, distinct from previously described quantal asynchrony. Although we observed minimal alteration of the somatically recorded action potential waveform, action potential propagation was altered. We observed a longer latency between somatic initiation and arrival at distal locations, which likely explains asynchronous EPSC peaks, and we observed broadening of the axonal spike, which likely underlies changes to evoked EPSC onset. No apparent changes in axon structure were observed, suggesting altered axonal excitability. In conclusion, we propose that local astrocyte support has an unappreciated role in maintaining glutamate release synchrony by disturbing axonal signal propagation. Certain glial cell types (oligodendrocytes, Schwann cells) facilitate the propagation of neuronal electrical signals, but a role for astrocytes has not been identified despite many other functions of astrocytes in supporting and modulating neuronal signaling. Under identical global conditions, we cultured neurons with or without local astrocyte support. Without local astrocytes, glutamate transmission was desynchronized by an alteration of the waveform and arrival time of axonal

  14. Quantitative strain analysis for advanced CMOS technology by Nano Beam Diffraction

    KAUST Repository

    Wang, Qingxiao; Zhu, Jinmin; Du, Anyan; Liu, Jinping; Hua, YouNan

    2010-01-01

    Nano Beam Diffraction has been used to analyze the local strain distribution in MOS transistors. The influence of wafer process on the channel strain has been systematically analyzed in this paper. The source/drain implantation can cause a little strain loss but the silicidation step is the key process in which dramatic strain loss has been found. © 2010 IEEE.

  15. Quantitative strain analysis for advanced CMOS technology by Nano Beam Diffraction

    KAUST Repository

    Wang, Qingxiao

    2010-07-01

    Nano Beam Diffraction has been used to analyze the local strain distribution in MOS transistors. The influence of wafer process on the channel strain has been systematically analyzed in this paper. The source/drain implantation can cause a little strain loss but the silicidation step is the key process in which dramatic strain loss has been found. © 2010 IEEE.

  16. Using cone beam computed tomography to detect the relationship between the periodontal bone loss and mucosal thickening of the maxillary sinus

    Directory of Open Access Journals (Sweden)

    Mahnaz Sheikhi

    2014-01-01

    Full Text Available Background: Maxillary sinuses are covered by a 1 mm thick mucous membrane that when this membrane becomes inflamed, the thickness may increase 10-15 times. The common causes of odontogenic sinusitis are dental abscesses and periodontal disease. Computed tomography (CT is considered the gold standard for sinus diagnosis. Recently, cone beam computed tomography (CBCT has been introduced for dental and maxillofacial imaging, which has several advantages over traditional CT, including lower radiation dose and chairside process. This study aims to find the association between mucosal thickening (MT of the sinus and periodontal bone loss (PBL and pulpoperiapical condition. Materials and Methods: A total of 180 CBCT images were reviewed. PBL was assessed in six points under each sinus at the mesial and distal sides of the upper second premolar and first and second molars by measuring the distance from the alveolar crest to the point 2 mm under the cemento-enamel junction (CEJ. The MT was assessed at six points in the floor of the sinus precisely over the mentioned points. To assess the possible role of pulpoperiapical condition on the sinus MT, the existing teeth were classified into five groups due to the probable effect of each condition on the pulp and peri-apex. The statistical association between MT of sinus and PBL and pulpoperiapical condition was assessed using SPSS software (SPSS Inc., version 16.0, Chicago, IL, USA and bivariate correlation and binary linear regression statistical tests (P < 0.05. Results: MT was observed in 39.4% of patients (mean = 4.68 ± 5.25 mm. PBL was seen in 33% of the patients (mean = 1.87 ± 1.63 mm. Linear regression test showed that there is an association between both PBL and pulpoperiapical condition and MT, but the effect of PBL was about 4 times stronger. Conclusion: This study showed that MT of the maxillary sinus was common among patients with PBL and MT of the maxillary sinus was significantly associated

  17. T1/T2 glottic cancer managed by external beam radiotherapy - the influence of pretreatment hemoglobin on local control

    International Nuclear Information System (INIS)

    Warde, P.R.; O'Sullivan, B.; Panzarella, T.; Keane, T.J.; Gullane, P.; Payne, D.; Liu, F.-F.; McLean, M.; Waldron, J.; Cummings, B.

    1996-01-01

    Purpose: Pretreatment hemoglobin (Hb) level has been reported to be an important prognostic factor for local control and survival in various malignancies. However in many settings, the adverse effect of a low Hb may be related to more advanced disease and the purpose of this analysis was to assess the influence of pretreatment Hb on local control in a large series of patients with a localised cancer (T1/T2 glottic cancer, AJCC 1992) treated in a standard fashion. Materials and Methods: Between Jan 1981 and Dec 1989, 735 patients (median age 63, 657 males 78 females) with T1/T2 glottic cancer were treated with RT. The standard RT prescription was 50Gy in 20 fractions over 4 weeks (97% patients). Factors studied for prognostic importance for local failure included pretreatment Hb (assessed as a continuous variable) age, sex, T category, anterior commissure involvement, subglottic extension, tumour bulk (presence of visible tumour vs subclinical disease), treatment time and RT technique (Cobalt vs 6 MV). Results: With a median follow-up of 6.8 years (range 0.2 - 14.3), 131 patients have relapsed for an actuarial 5-year relapse free rate of 81.7%. The 5-year actuarial survival was 75.8%, cause specific survival - 92.4%. The median pretreatment hemoglobin level was 14.8 g/dl and was the same in all T categories. On multivariate analysis, using the Cox proportional hazards model, pretreatment Hb (p=0.001) predicted for local failure after RT. The relative risk (RR) for relapse was calculated for various Hb levels eg the RR for a Hb of 12 g/dl vs a Hb of 15 g/dl was 1.8, (95% C.I. 1.3 - 2.7). Previously noted factors including gender (p=0.0038), T category (p=0.007)) as well as tumour bulk (p=0.02) were also prognostically important for local control. Conclusions: This analysis, in a large number of similarly treated patients, indicates that pretreatment Hb is an independent prognostic factor for local control in patients with T1/T2 carcinoma of the glottis treated with

  18. Sensitivity analysis of local uncertainties in large break loss-of-coolant accident (LB-LOCA) thermo-mechanical simulations

    Energy Technology Data Exchange (ETDEWEB)

    Arkoma, Asko, E-mail: asko.arkoma@vtt.fi; Ikonen, Timo

    2016-08-15

    Highlights: • A sensitivity analysis using the data from EPR LB-LOCA simulations is done. • A procedure to analyze such complex data is outlined. • Both visual and quantitative methods are used. • Input factors related to core design are identified as most significant. - Abstract: In this paper, a sensitivity analysis for the data originating from a large break loss-of-coolant accident (LB-LOCA) analysis of an EPR-type nuclear power plant is presented. In the preceding LOCA analysis, the number of failing fuel rods in the accident was established (Arkoma et al., 2015). However, the underlying causes for rod failures were not addressed. It is essential to bring out which input parameters and boundary conditions have significance to the outcome of the analysis, i.e. the ballooning and burst of the rods. Due to complexity of the existing data, the first part of the analysis consists of defining the relevant input parameters for the sensitivity analysis. Then, selected sensitivity measures are calculated between the chosen input and output parameters. The ultimate goal is to develop a systematic procedure for the sensitivity analysis of statistical LOCA simulation that takes into account the various sources of uncertainties in the calculation chain. In the current analysis, the most relevant parameters with respect to the cladding integrity are the decay heat power during the transient, the thermal hydraulic conditions in the rod’s location in reactor, and the steady-state irradiation history of the rod. Meanwhile, the tolerances in fuel manufacturing parameters were found to have negligible effect on cladding deformation.

  19. Stereotactic Ablative Radiosurgery for Locally-Advanced or Recurrent Skull Base Malignancies with Prior External Beam Radiation Therapy

    Directory of Open Access Journals (Sweden)

    Karen Mann Xu

    2015-03-01

    Full Text Available Purpose: Stereotactic ablative radiotherapy (SABR is an attractive modality to treat malignancies invading the skull base as it can deliver a highly conformal dose with minimal toxicity. However, variation exists in the prescribed dose and fractionation. The purpose of our study is to examine the local control, survival and toxicities in SABR for the treatment of malignant skull base tumors. Methods and Materials: A total of 31 patients and 40 locally-advanced or recurrent head and neck malignancies involving the skull base treated with a common SABR regimen which delivers a radiation dose of 44 Gy in 5 fractions from January 1st, 2004 to December 31st, 2013 were retrospectively reviewed. The local control rate (LC, progression-free survival rate (PFS, overall survival rate (OS and toxicities were reported.Results: The median follow-up time of all patients was 11.4 months (range: 0.6-67.2 months. The median tumor volume was 27 cm3 (range: 2.4-205 cm3. All patients received prior EBRT with a median radiation dose of 64 Gy (range: 24-75.6 Gy delivered in 12 to 42 fractions. 20 patients had surgeries prior to SABR. 19 patients received chemotherapy. Specifically, 8 patients received concurrent cetuximab (ErbituxTM with SABR. The median time-to-progression (TTP was 3.3 months (range: 0-16.9 months. For the 29 patients (93.5% who died, the median time from the end of first SABR to death was 10.3 months (range: 0.5-41.4 months. The estimated 1-year overall survival (OS rate was 35%. The estimated 2-year OS rate was 12%. Treatment was well-tolerated without grade 4 or 5 treatment-related toxicities.Conclusions: SABR has been shown to achieve low toxicities in locally-advanced or recurrent, previously irradiated head and neck malignancies invading the skull base.

  20. A comparison of CT- and ultrasound-based imaging to localize the prostate for external beam radiotherapy

    International Nuclear Information System (INIS)

    McNair, Helen A.; Mangar, Stephen A.; Coffey, Jerome; Shoulders, Beverley; Hansen, Vibeke N.; Norman, Andrew; Staffurth, John; Sohaib, S. Aslam; Warrington, Alan P.; Dearnaley, David P.

    2006-01-01

    Purpose: This study assesses the accuracy of NOMOS B-mode acquisition and targeting system (BAT) compared with computed tomography (CT) in localizing the prostate. Methods and Materials: Twenty-six patients were CT scanned, and the prostate was localized by 3 observers using the BAT system. The BAT couch shift measurements were compared with the CT localization. Six of the patients had gold markers present in the prostate, and the prostate movement determined by BAT was compared with the movement determined by the gold markers. Results: Using the BAT system, the 3 observers determined the prostate position to be a mean of 1-5 mm over all directions with respect to the CT. The proportion of readings with a difference >3 mm between the observers was in the range of 25% to 44%. The prostate movement based on gold markers was an average of 3-5 mm different from that measured by BAT. The literature assessing the accuracy and reproducibility on BAT is summarized and compared with our findings. Conclusions: We have found that there are systematic differences between the BAT-defined prostate position compared with that estimated on CT using gold grain marker seeds

  1. Thermally induced diffraction losses for a Gaussian pump beam and optimization of the mode-to-pump ratio in an end-pumped Nd:GdVO4 laser

    International Nuclear Information System (INIS)

    Wang, Y T; Li, W J; Pan, L L; Yu, J T; Zhang, R H

    2013-01-01

    The analytical model of thermally induced diffraction losses for a Gaussian pump beam are derived as functions of the mode-to-pump ratio and pump power in end-pumped Nd-doped lasers considering the energy transfer upconversion effects. The mode-to-pump ratio is optimized based on it. The results show that the optimum mode-to-pump ratio with the thermally induced diffraction losses is less than 0.65, and it is less than the results in which the thermally induced diffraction losses are neglected. The theoretical model is applied to a diode-end-pumped Nd:GdVO 4 laser operating at 1342 nm, and the theoretical calculations are in good agreement with the experimental results. (paper)

  2. Vanishing Clams on an Iberian Beach: Local Consequences and Global Implications of Accelerating Loss of Shells to Tourism

    Science.gov (United States)

    Kowalewski, Michał; Domènech, Rosa; Martinell, Jordi

    2014-01-01

    Multi-decadal increase in shell removal by tourists, a process that may accelerate degradation of natural habitats, was quantified via two series of monthly surveys, conducted thirty years apart (1978–1981 and 2008–2010) in one small embayment on the Mediterranean coast of the Iberian Peninsula. Over the last three decades, the local tourist arrivals have increased almost three-fold (2.74), while the area has remained unaffected by urban encroachment and commercial fisheries. During the same time interval the abundance of mollusk shells along the shoreline decreased by a comparable factor (2.62) and was significantly and negatively correlated with tourist arrivals (r = −0.52). The strength of the correlation increased when data were restricted to months with high tourist arrivals (r = −0.72). In contrast, the maximum monthly wave energy (an indirect proxy for changes in rate of onshore shell transport) was not significantly correlated with shell abundance (r = 0.10). Similarly, rank dominance of common species, drilling predation intensity, and body size-frequency distribution patterns have all remained stable over recent decades. A four-fold increase in global tourist arrivals over the last 30 years may have induced a comparable worldwide acceleration in shell removal from marine shorelines, resulting in multiple, currently unquantifiable, habitat changes such as increased beach erosion, changes in calcium carbonate recycling, and declines in diversity and abundance of organisms, which are dependent on shell availability. PMID:24421895

  3. Vanishing clams on an Iberian beach: local consequences and global implications of accelerating loss of shells to tourism.

    Science.gov (United States)

    Kowalewski, Michał; Domènech, Rosa; Martinell, Jordi

    2014-01-01

    Multi-decadal increase in shell removal by tourists, a process that may accelerate degradation of natural habitats, was quantified via two series of monthly surveys, conducted thirty years apart (1978-1981 and 2008-2010) in one small embayment on the Mediterranean coast of the Iberian Peninsula. Over the last three decades, the local tourist arrivals have increased almost three-fold (2.74), while the area has remained unaffected by urban encroachment and commercial fisheries. During the same time interval the abundance of mollusk shells along the shoreline decreased by a comparable factor (2.62) and was significantly and negatively correlated with tourist arrivals (r = -0.52). The strength of the correlation increased when data were restricted to months with high tourist arrivals (r = -0.72). In contrast, the maximum monthly wave energy (an indirect proxy for changes in rate of onshore shell transport) was not significantly correlated with shell abundance (r = 0.10). Similarly, rank dominance of common species, drilling predation intensity, and body size-frequency distribution patterns have all remained stable over recent decades. A four-fold increase in global tourist arrivals over the last 30 years may have induced a comparable worldwide acceleration in shell removal from marine shorelines, resulting in multiple, currently unquantifiable, habitat changes such as increased beach erosion, changes in calcium carbonate recycling, and declines in diversity and abundance of organisms, which are dependent on shell availability.

  4. Exact solutions for the static bending of Euler-Bernoulli beams using Eringen’s two-phase local/nonlocal model

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Y. B. [Department of Mathematics, ShaoXing University, No.900, ChengNan Avenue 312000, ShaoXing, Zhejiang (China); Zhu, X. W., E-mail: xiaowuzhu1026@znufe.edu.cn [School of Statistics and Mathematics, Zhongnan University of Economics and Law, Wuhan 430073 (China); Dai, H. H. [Department of Mathematics, City University of HongKong, 83 Tat Chee Avenue, Kowloon Tong, Hong Kong (China)

    2016-08-15

    Though widely used in modelling nano- and micro- structures, Eringen’s differential model shows some inconsistencies and recent study has demonstrated its differences between the integral model, which then implies the necessity of using the latter model. In this paper, an analytical study is taken to analyze static bending of nonlocal Euler-Bernoulli beams using Eringen’s two-phase local/nonlocal model. Firstly, a reduction method is proved rigorously, with which the integral equation in consideration can be reduced to a differential equation with mixed boundary value conditions. Then, the static bending problem is formulated and four types of boundary conditions with various loadings are considered. By solving the corresponding differential equations, exact solutions are obtained explicitly in all of the cases, especially for the paradoxical cantilever beam problem. Finally, asymptotic analysis of the exact solutions reveals clearly that, unlike the differential model, the integral model adopted herein has a consistent softening effect. Comparisons are also made with existing analytical and numerical results, which further shows the advantages of the analytical results obtained. Additionally, it seems that the once controversial nonlocal bar problem in the literature is well resolved by the reduction method.

  5. Exact solutions for the static bending of Euler-Bernoulli beams using Eringen’s two-phase local/nonlocal model

    International Nuclear Information System (INIS)

    Wang, Y. B.; Zhu, X. W.; Dai, H. H.

    2016-01-01

    Though widely used in modelling nano- and micro- structures, Eringen’s differential model shows some inconsistencies and recent study has demonstrated its differences between the integral model, which then implies the necessity of using the latter model. In this paper, an analytical study is taken to analyze static bending of nonlocal Euler-Bernoulli beams using Eringen’s two-phase local/nonlocal model. Firstly, a reduction method is proved rigorously, with which the integral equation in consideration can be reduced to a differential equation with mixed boundary value conditions. Then, the static bending problem is formulated and four types of boundary conditions with various loadings are considered. By solving the corresponding differential equations, exact solutions are obtained explicitly in all of the cases, especially for the paradoxical cantilever beam problem. Finally, asymptotic analysis of the exact solutions reveals clearly that, unlike the differential model, the integral model adopted herein has a consistent softening effect. Comparisons are also made with existing analytical and numerical results, which further shows the advantages of the analytical results obtained. Additionally, it seems that the once controversial nonlocal bar problem in the literature is well resolved by the reduction method.

  6. Prostate specific antigen levels during and after external beam radiotherapy for localized carcinoma of the prostate: Predictor of therapeutic efficancy

    International Nuclear Information System (INIS)

    Rodrigus, P.; Landeghem, A.A.J. van

    1992-01-01

    For 105 patients with locoregional carcinoma of the prostate, prostate specific antigen (PSA) levels were evaluated before, during and after external beam radiotherapy. The median follow-up is 17 months. In 51 patients (48.5%) initial PSA levels exceeded the maximum normal value of 20 ng/ml. Nine patients kept non-declining high levels just after radiotherapy. Only one of these is free of disease. Assuming PSA levels decrease exponentially during radiotherapy, a mean half-life of 62 days (median 54, SD 26 days) was calculated. Three out of five patients with a PSA half-life of more than 88 days relapsed as compared to a 8% (3/37) relapse rate in patients with a 'normal' half-life. Prolonged PSA half-life suggests residual disease. PSA levels are expected to further decrease after radiation. Six months after irradiation persistent high PSA levels were found in 14/51 (27.5%) patients. Only four of them had no evidence of manifest disease. Important negative prognostic factors for disease control in our series were non-declining high levels of PSA, a PSA serum half-life exceeding 88 days and persistence of elevated PSA values longer than six months after treatment. In our opinion, PSA is a valuable marker in the follow-up of prostate cancer patients during and after radiotherapy. (orig.) [de

  7. Treatment of localized prostate cancer using a combination of high dose rate lridium-192 brachytherapy and external beam irradiation: Initial Australian experience

    International Nuclear Information System (INIS)

    Stevens, M.J.; Stricker, P.D.; Brenner, P.C.; Kooner, R.; O'Neil, G.F.A.; Duval, P.J.; Jagavkar, R.S.; Cross, P.; Saalfeld, J.; Martland, J.

    2003-01-01

    Combination high dose rate brachytherapy (HDRB) and external beam radiation therapy is technically and clinically feasible as definitive treatment for localized prostate cancer. We report the first large Australian experience using this technique of radiation dose escalation in 82 patients with intermediate- and high-risk disease. With a median follow up of 3 years (156 weeks), complications were low and overall prostate-specific antigen progression-free survival was 91% using the American Society for Therapeutic Radiology and Oncology consensus definition. The delivery of hypofractionated radiation through the HDRB component shortens overall treatment time and is both biologically and logistically advantageous. As a radiation boost strategy, HDRB is easy to learn and could be introduced into most facilities with brachytherapy capability. Copyright (2003) Blackwell Science Pty Ltd

  8. Long-term data from a small mammal community reveal loss of diversity and potential effects of local climate change.

    Science.gov (United States)

    Santoro, Simone; Sanchez-Suarez, Cristina; Rouco, Carlos; Palomo, L Javier; Fernández, M Carmen; Kufner, Maura B; Moreno, Sacramento

    2017-10-01

    Climate change affects distribution and persistence of species. However, forecasting species' responses to these changes requires long-term data series that are often lacking in ecological studies. We used 15 years of small mammal trapping data collected between 1978 and 2015 in 3 areas at Doñana National Park (southwest Spain) to (i) describe changes in species composition and (ii) test the association between local climate conditions and size of small mammal populations. Overall, 5 species were captured: wood mouse Apodemus sylvaticus , algerian mouse Mus spretus , greater white-toothed shrew Crocidura russula , garden dormouse Eliomys quercinus , and black rat Rattus rattus . The temporal pattern in the proportion of captures of each species suggests that the small mammal diversity declined with time. Although the larger species (e.g., E. quercinus ), better adapted to colder climate, have disappeared from our trapping records, M. spretus , a small species inhabiting southwest Europe and the Mediterranean coast of Africa, currently is almost the only trapped species. We used 2-level hierarchical models to separate changes in abundance from changes in probability of capture using records of A. sylvaticus in all 3 areas and of M. spretus in 1. We found that heavy rainfall and low temperatures were positively related to abundance of A. sylvaticus , and that the number of extremely hot days was negatively related to abundance of M. spretus . Despite other mechanisms are likely to be involved, our findings support the importance of climate for the distribution and persistence of these species and raise conservation concerns about potential cascading effects in the Doñana ecosystem.

  9. Three-year experience with the Sophono in children with congenital conductive unilateral hearing loss: tolerability, audiometry, and sound localization compared to a bone-anchored hearing aid.

    Science.gov (United States)

    Nelissen, Rik C; Agterberg, Martijn J H; Hol, Myrthe K S; Snik, Ad F M

    2016-10-01

    Bone conduction devices (BCDs) are advocated as an amplification option for patients with congenital conductive unilateral hearing loss (UHL), while other treatment options could also be considered. The current study compared a transcutaneous BCD (Sophono) with a percutaneous BCD (bone-anchored hearing aid, BAHA) in 12 children with congenital conductive UHL. Tolerability, audiometry, and sound localization abilities with both types of BCD were studied retrospectively. The mean follow-up was 3.6 years for the Sophono users (n = 6) and 4.7 years for the BAHA users (n = 6). In each group, two patients had stopped using their BCD. Tolerability was favorable for the Sophono. Aided thresholds with the Sophono were unsatisfactory, as they did not reach under a mean pure tone average of 30 dB HL. Sound localization generally improved with both the Sophono and the BAHA, although localization abilities did not reach the level of normal hearing children. These findings, together with previously reported outcomes, are important to take into account when counseling patients and their caretakers. The selection of a suitable amplification option should always be made deliberately and on individual basis for each patient in this diverse group of children with congenital conductive UHL.

  10. External beam radiation therapy for clinically localized prostate cancer: when and how we optimize with concurrent hormonal deprivation.

    Science.gov (United States)

    Koontz, Bridget F; Lee, W Robert

    2011-10-01

    Androgen deprivation plays a major role in the treatment of prostate cancer.Preclinical studies have shown that androgen deprivation provides both an independent cytotoxic effect and radiosensitization on prostate tumors. For men with non-metastatic prostate cancer, the addition of androgen deprivation to radiotherapy has been shown to improve survival for intermediate and high risk disease compared to radiation alone.This review discusses the clinical trial data regarding combination of androgen deprivation and radiation and provides recommendations for its use in men undergoing radiotherapy for localized prostate cancer.

  11. Prognostic Value of External Beam Radiation Therapy in Patients Treated With Surgical Resection and Intraoperative Electron Beam Radiation Therapy for Locally Recurrent Soft Tissue Sarcoma: A Multicentric Long-Term Outcome Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Calvo, Felipe A. [Department of Oncology, Hospital General Universitario Gregorio Marañón, Madrid (Spain); School of Medicine, Complutense University, Madrid (Spain); Sole, Claudio V., E-mail: cvsole@uc.cl [Department of Oncology, Hospital General Universitario Gregorio Marañón, Madrid (Spain); School of Medicine, Complutense University, Madrid (Spain); Service of Radiation Oncology, Instituto de Radiomedicina, Santiago (Chile); Cambeiro, Mauricio [Service of Radiation Oncology, Clínica Universitaria, Universidad de Navarra, Pamplona (Spain); Montero, Angel; Polo, Alfredo [Service of Radiation Oncology, Hospital Universitario Ramón y Cajal, Universidad de Alcala, Madrid (Spain); Gonzalez, Carmen [School of Medicine, Complutense University, Madrid (Spain); Service of Radiation Oncology, Instituto de Radiomedicina, Santiago (Chile); Service of Radiation Oncology, Clínica Universitaria, Universidad de Navarra, Pamplona (Spain); Service of Radiation Oncology, Hospital Universitario Ramón y Cajal, Universidad de Alcala, Madrid (Spain); Service of Radiation Oncology, Hospital General Universitario Gregorio Marañón, Madrid (Spain); Cuervo, Miguel [Service of Orthopedics and Traumatology, Hospital General Universitario Gregorio Marañón, Madrid (Spain); San Julian, Mikel [Service of Orthopedics and Traumatology, Clínica Universitaria, Universidad de Navarra, Pamplona (Spain); and others

    2014-01-01

    Background: A joint analysis of data from centers involved in the Spanish Cooperative Initiative for Intraoperative Electron Radiotherapy was performed to investigate long-term outcomes of locally recurrent soft tissue sarcoma (LR-STS) patients treated with a multidisciplinary approach. Methods and Materials: Patients with a histologic diagnosis of LR-STS (extremity, 43%; trunk wall, 24%; retroperitoneum, 33%) and no distant metastases who underwent radical surgery and intraoperative electron radiation therapy (IOERT; median dose, 12.5 Gy) were considered eligible for participation in this study. In addition, 62% received external beam radiation therapy (EBRT; median dose, 50 Gy). Results: From 1986 to 2012, a total of 103 patients from 3 Spanish expert IOERT institutions were analyzed. With a median follow-up of 57 months (range, 2-311 months), 5-year local control (LC) was 60%. The 5-year IORT in-field control, disease-free survival (DFS), and overall survival were 73%, 43%, and 52%, respectively. In the multivariate analysis, no EBRT to treat the LR-STS (P=.02) and microscopically involved margin resection status (P=.04) retained significance in relation to LC. With regard to IORT in-field control, only not delivering EBRT to the LR-STS retained significance in the multivariate analysis (P=.03). Conclusion: This joint analysis revealed that surgical margin and EBRT affect LC but that, given the high risk of distant metastases, DFS remains modest. Intensified local treatment needs to be further tested in the context of more efficient concurrent, neoadjuvant, and adjuvant systemic therapy.

  12. Prognostic Value of External Beam Radiation Therapy in Patients Treated With Surgical Resection and Intraoperative Electron Beam Radiation Therapy for Locally Recurrent Soft Tissue Sarcoma: A Multicentric Long-Term Outcome Analysis

    International Nuclear Information System (INIS)

    Calvo, Felipe A.; Sole, Claudio V.; Cambeiro, Mauricio; Montero, Angel; Polo, Alfredo; Gonzalez, Carmen; Cuervo, Miguel; San Julian, Mikel

    2014-01-01

    Background: A joint analysis of data from centers involved in the Spanish Cooperative Initiative for Intraoperative Electron Radiotherapy was performed to investigate long-term outcomes of locally recurrent soft tissue sarcoma (LR-STS) patients treated with a multidisciplinary approach. Methods and Materials: Patients with a histologic diagnosis of LR-STS (extremity, 43%; trunk wall, 24%; retroperitoneum, 33%) and no distant metastases who underwent radical surgery and intraoperative electron radiation therapy (IOERT; median dose, 12.5 Gy) were considered eligible for participation in this study. In addition, 62% received external beam radiation therapy (EBRT; median dose, 50 Gy). Results: From 1986 to 2012, a total of 103 patients from 3 Spanish expert IOERT institutions were analyzed. With a median follow-up of 57 months (range, 2-311 months), 5-year local control (LC) was 60%. The 5-year IORT in-field control, disease-free survival (DFS), and overall survival were 73%, 43%, and 52%, respectively. In the multivariate analysis, no EBRT to treat the LR-STS (P=.02) and microscopically involved margin resection status (P=.04) retained significance in relation to LC. With regard to IORT in-field control, only not delivering EBRT to the LR-STS retained significance in the multivariate analysis (P=.03). Conclusion: This joint analysis revealed that surgical margin and EBRT affect LC but that, given the high risk of distant metastases, DFS remains modest. Intensified local treatment needs to be further tested in the context of more efficient concurrent, neoadjuvant, and adjuvant systemic therapy

  13. Health impact assessment and monetary valuation of IQ loss in pre-school children due to lead exposure through locally produced food.

    Science.gov (United States)

    Bierkens, J; Buekers, J; Van Holderbeke, M; Torfs, R

    2012-01-01

    A case study has been performed which involved the full chain assessment from policy drivers to health effect quantification of lead exposure through locally produced food on loss of IQ in pre-school children at the population level across the EU-27, including monetary valuation of the estimated health impact. Main policy scenarios cover the period from 2000 to 2020 and include the most important Community policy developments expected to affect the environmental release of lead (Pb) and corresponding human exposure patterns. Three distinct scenarios were explored: the emission situation based on 2000 data, a business-as-usual scenario (BAU) up to 2010 and 2020 and a scenario incorporating the most likely technological change expected (Most Feasible Technical Reductions, MFTR) in response to current and future legislation. Consecutive model calculations (MSCE-HM, WATSON, XtraFOOD, IEUBK) were performed by different partners on the project as part of the full chain approach to derive estimates of blood lead (B-Pb) levels in children as a consequence of the consumption of local produce. The estimated B-Pb levels were translated into an average loss of IQ points/child using an empirical relationship based on a meta-analysis performed by Schwartz (1994). The calculated losses in IQ points were subsequently further translated into the average cost/child using a cost estimate of €10.000 per loss of IQ point based on data from a literature review. The estimated average reduction of cost/child (%) for all countries considered in 2010 under BAU and MFTR are 12.16 and 18.08% as compared to base line conditions, respectively. In 2020 the percentages amount to 20.19 and 23.39%. The case study provides an example of the full-chain impact pathway approach taking into account all foreseeable pathways both for assessing the environmental fate and the associated human exposure and the mode of toxic action to arrive at quantitative estimates of health impacts at the individual and

  14. External Beam Radiation Therapy and Abiraterone in Men With Localized Prostate Cancer: Safety and Effect on Tissue Androgens

    International Nuclear Information System (INIS)

    Cho, Eunpi; Mostaghel, Elahe A.; Russell, Kenneth J.; Liao, Jay J.; Konodi, Mark A.; Kurland, Brenda F.; Marck, Brett T.; Matsumoto, Alvin M.; Dalkin, Bruce L.; Montgomery, R. Bruce

    2015-01-01

    Purpose: Optimizing androgen suppression may provide better control of localized prostate cancer (PCa). Numerous trials have supported the benefit of combining androgen deprivation therapy with definitive radiation therapy in men with locally advanced or high-grade disease. Addition of abiraterone to luteinizing hormone-releasing hormone agonist (LHRHa) with radiation has not been reported. We examined the safety of this combination as well as its impact on androgen suppression. Methods and Materials: A prospective, phase 2 study was conducted in men with localized PCa treated with 6 months of neoadjuvant and concurrent abiraterone with LHRHa and radiation. Duration of adjuvant LHRHa was at the discretion of the treating clinician. Prostate biopsy assays were obtained prior to the start of therapy and prior to radiation. Sera and tissue androgen levels were measured by liquid chromatography-tandem mass spectrometry. Results: A total of 22 men with intermediate- (n=3) and high-risk PCa (n=19) received study therapy. Sixteen men completed the intended course of abiraterone, and 19 men completed planned radiation to 77.4 to 81 Gy. Radiation to pelvic nodes was administered in 20 men. The following grade 3 toxicities were reported: lymphopenia (14 patients), fatigue (1 patient), transaminitis (2 patients), hypertension (2 patients), and hypokalemia (1 patient). There were no grade 4 toxicities. All 21 men who complied with at least 3 months of abiraterone therapy had a preradiation prostate-specific antigen (PSA) concentration nadir of <0.3 ng/mL. Median levels of tissue androgen downstream of CYP17A were significantly suppressed after treatment with abiraterone, and upstream steroids were increased. At median follow-up of 21 months (range: 3-37 months), only 1 patient (who had discontinued abiraterone at 3 months) had biochemical relapse. Conclusions: Addition of abiraterone to LHRHa with radiation is safe and achieves effective prostatic androgen suppression

  15. External Beam Radiation Therapy and Abiraterone in Men With Localized Prostate Cancer: Safety and Effect on Tissue Androgens

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Eunpi [University of Washington School of Medicine, Seattle, Washington (United States); Fred Hutchinson Cancer Research Center, Seattle, Washington (United States); Mostaghel, Elahe A. [Fred Hutchinson Cancer Research Center, Seattle, Washington (United States); Russell, Kenneth J.; Liao, Jay J.; Konodi, Mark A. [University of Washington School of Medicine, Seattle, Washington (United States); Kurland, Brenda F. [University of Pittsburgh, Pittsburgh, Pennsylvania (United States); Marck, Brett T. [Veterans Affairs Puget Sound Health Care System, Seattle, Washington (United States); Matsumoto, Alvin M. [University of Washington School of Medicine, Seattle, Washington (United States); Veterans Affairs Puget Sound Health Care System, Seattle, Washington (United States); Dalkin, Bruce L. [University of Washington School of Medicine, Seattle, Washington (United States); Montgomery, R. Bruce, E-mail: rbmontgo@uw.edu [University of Washington School of Medicine, Seattle, Washington (United States)

    2015-06-01

    Purpose: Optimizing androgen suppression may provide better control of localized prostate cancer (PCa). Numerous trials have supported the benefit of combining androgen deprivation therapy with definitive radiation therapy in men with locally advanced or high-grade disease. Addition of abiraterone to luteinizing hormone-releasing hormone agonist (LHRHa) with radiation has not been reported. We examined the safety of this combination as well as its impact on androgen suppression. Methods and Materials: A prospective, phase 2 study was conducted in men with localized PCa treated with 6 months of neoadjuvant and concurrent abiraterone with LHRHa and radiation. Duration of adjuvant LHRHa was at the discretion of the treating clinician. Prostate biopsy assays were obtained prior to the start of therapy and prior to radiation. Sera and tissue androgen levels were measured by liquid chromatography-tandem mass spectrometry. Results: A total of 22 men with intermediate- (n=3) and high-risk PCa (n=19) received study therapy. Sixteen men completed the intended course of abiraterone, and 19 men completed planned radiation to 77.4 to 81 Gy. Radiation to pelvic nodes was administered in 20 men. The following grade 3 toxicities were reported: lymphopenia (14 patients), fatigue (1 patient), transaminitis (2 patients), hypertension (2 patients), and hypokalemia (1 patient). There were no grade 4 toxicities. All 21 men who complied with at least 3 months of abiraterone therapy had a preradiation prostate-specific antigen (PSA) concentration nadir of <0.3 ng/mL. Median levels of tissue androgen downstream of CYP17A were significantly suppressed after treatment with abiraterone, and upstream steroids were increased. At median follow-up of 21 months (range: 3-37 months), only 1 patient (who had discontinued abiraterone at 3 months) had biochemical relapse. Conclusions: Addition of abiraterone to LHRHa with radiation is safe and achieves effective prostatic androgen suppression

  16. Multivariate normal tissue complication probability modeling of gastrointestinal toxicity after external beam radiotherapy for localized prostate cancer

    International Nuclear Information System (INIS)

    Cella, Laura; D’Avino, Vittoria; Liuzzi, Raffaele; Conson, Manuel; Doria, Francesca; Faiella, Adriana; Loffredo, Filomena; Salvatore, Marco; Pacelli, Roberto

    2013-01-01

    The risk of radio-induced gastrointestinal (GI) complications is affected by several factors other than the dose to the rectum such as patient characteristics, hormonal or antihypertensive therapy, and acute rectal toxicity. Purpose of this work is to study clinical and dosimetric parameters impacting on late GI toxicity after prostate external beam radiotherapy (RT) and to establish multivariate normal tissue complication probability (NTCP) model for radiation-induced GI complications. A total of 57 men who had undergone definitive RT for prostate cancer were evaluated for GI events classified using the RTOG/EORTC scoring system. Their median age was 73 years (range 53–85). The patients were assessed for GI toxicity before, during, and periodically after RT completion. Several clinical variables along with rectum dose-volume parameters (Vx) were collected and their correlation to GI toxicity was analyzed by Spearman’s rank correlation coefficient (Rs). Multivariate logistic regression method using resampling techniques was applied to select model order and parameters for NTCP modeling. Model performance was evaluated through the area under the receiver operating characteristic curve (AUC). At a median follow-up of 30 months, 37% (21/57) patients developed G1-2 acute GI events while 33% (19/57) were diagnosed with G1-2 late GI events. An NTCP model for late mild/moderate GI toxicity based on three variables including V65 (OR = 1.03), antihypertensive and/or anticoagulant (AH/AC) drugs (OR = 0.24), and acute GI toxicity (OR = 4.3) was selected as the most predictive model (Rs = 0.47, p < 0.001; AUC = 0.79). This three-variable model outperforms the logistic model based on V65 only (Rs = 0.28, p < 0.001; AUC = 0.69). We propose a logistic NTCP model for late GI toxicity considering not only rectal irradiation dose but also clinical patient-specific factors. Accordingly, the risk of G1-2 late GI increases as V65 increases, it is higher for patients experiencing

  17. Surface potential, charging and local current transport of individual Ge quantum dots grown by molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Singha, R.K. [Department of Physics, Visva-Bharati, Santiniketan 731235 (India); Manna, S.; Bar, R.; Das, S. [Department of Physics, Indian Institute of Technology-Kharagpur, Kharagpur 721302 (India); Ray, S.K., E-mail: physkr@phy.iitkgp.ernet.in [Department of Physics, Indian Institute of Technology-Kharagpur, Kharagpur 721302 (India)

    2017-06-15

    Highlights: We have elaborately explained the individual Ge QD charging phenomena and current transport, which is very important to understand the Ge/Si nano devices. This paper will give a flavor to properly understand these phenomena linked together along with the photocurrent mechanism which is related to the Ge/Si valence band offset. • Both the CAFM and KPFM techniques point out the functionality of doping nature of the underneath Si substrate on the aforementioned characteristics of Ge QDs. • Analysis of the surface potential mapping using KPFM technique yields an approximate valence band offset measurement which is required to understand the intra-valence transition of holes for the realization of long wavelength infrared photodetector. • KPFM and CAFM can be utilized to explore the charging/discharging phenomena of dots and their composition variations. • Current-voltage (I–V) characteristics of the individual Ge QD strongly depends on the individual QD size. • Energy band diagrams for diamond tip and Ge QD shows the higher barrier for electrons and lower barrier for holes allowing the easy tunneling for holes to dominate the transport. - Abstract: It is fundamentally important to understand the nanoscale electronic properties of a single quantum dot (QD) contrary to an ensemble of QDs. Kelvin probe force microscopy (KPFM) and conductive atomic force microscopy (CAFM) are two important tools, which could be employed to probe surface potential, charging phenomena, and current transport mechanism of individual QD. We demonstrate the aforementioned characteristics of self-assembled Ge QDs, which was grown on Si substrates by solid source molecular beam epitaxy driven by the Stranski-Krastanov method. Study reveals that each Ge QD acts as charge storage node even at zero applied bias. The shape, size and density of QDs could be well probed by CAFM and KPFM, whereas QD facets could be better resolved by the conductive tip. The CAFM investigation

  18. Chest Reirradiation With External Beam Radiotherapy for Locally Recurrent Non-Small-Cell Lung Cancer: A Review

    International Nuclear Information System (INIS)

    Jeremic, Branislav; Videtic, Gregory M.M.

    2011-01-01

    Lung cancer remains one of the most prevalent and deadliest malignancies worldwide. For 2008, the International Agency for the Research of Cancer (IARC) estimated 1.6 million new cancer cases of lung cancer (1.095 million in men and 0.514 million in women), with an associated 1.38 million deaths (0.95 million in men and 0.43 million in women). In the United States, lung cancer remained the number one cancer killer for both sexes in 2009, with 219,440 new cases diagnosed overall and an estimated 159,390 deaths. Recent biological and technological advances in lung cancer management notwithstanding, disease recurrence is still the dominant cause of death after initial treatment of lung cancer. This is irrespective of histology (NSCLC vs. small cell cancer), stage (early vs. locally advanced vs. metastatic), or initial treatment (surgery, RT, chemotherapy [CHT] or combinations thereof). Time to recurrence of lung cancer is not predictable, with some failures appearing early and others manifesting years later. Patterns of failure are also not easily anticipated as local (e.g., lung parenchyma, bronchial stump, or chest wall), regional (e.g., mediastinal lymph nodes), or distant (e.g., brain, liver, or bone) recurrences can appear alone or in combination. Whatever the presentation, recurrent lung cancer has historically been judged almost universally fatal as only rarely did efforts at treatment lead to control, let alone cure. More importantly, recurrence is often associated with significant distress requiring substantial supportive treatment. Recurrence leads ultimately to a significant decrease in patient quality of life, making further interventions even more limited. Because of the bleak outcome associated with recurrence, palliative retreatment has nonetheless often been attempted precisely as a means of preventing this decline in quality of life and/or reversing symptoms. However, complicating these attempts at retreatment has been the forms of initial therapy

  19. Localized Beampipe Heating due to $e^{-}$ Capture and Nuclear Excitation in Heavy Ion Colliders

    CERN Document Server

    Klein, S R

    2001-01-01

    At heavy ion colliders, two major sources of beam loss are expected to be $e^+e^-$ production, where the $e^-$ is bound to one of the nuclei, and photonuclear excitation and decay via neutron emission. Both processes alter the ions charged to mass ratio by well defined amounts, creating beams of particles with altered magnetic rigidity. These beams will deposit their energy in a localized region of the accelerator, causing localized heating, The size of the target region depends on the collider optics. For medium and heavy ions, at design luminosity at the Large Hadron Collider, local heating may be more than an order of magnitude higher than expected. This could cause magnet quenches if the local cooling is inadequate. The altered-rigidity beams will also produce localized radiation damage. The beams could also be extracted and used for fixed target experiments.

  20. Localized melt-scan strategy for site specific control of grain size and primary dendrite arm spacing in electron beam additive manufacturing

    International Nuclear Information System (INIS)

    Raghavan, Narendran; Simunovic, Srdjan; Dehoff, Ryan; Plotkowski, Alex; Turner, John; Kirka, Michael; Babu, Suresh

    2017-01-01

    In addition to design geometry, surface roughness, and solid-state phase transformation, solidification microstructure plays a crucial role in controlling the performance of additively manufactured components. Crystallographic texture, primary dendrite arm spacing (PDAS), and grain size are directly correlated to local solidification conditions. We have developed a new melt-scan strategy for inducing site specific, on-demand control of solidification microstructure. We were able to induce variations in grain size (30 μm–150 μm) and PDAS (4 μm - 10 μm) in Inconel 718 parts produced by the electron beam additive manufacturing system (Arcam ® ). A conventional raster melt-scan resulted in a grain size of about 600 μm. The observed variations in grain size with different melt-scan strategies are rationalized using a numerical thermal and solidification model which accounts for the transient curvature of the melt pool and associated thermal gradients and liquid-solid interface velocities. The refinement in grain size at high cooling rates (>10 4  K/s) is also attributed to the potential heterogeneous nucleation of grains ahead of the epitaxially growing solidification front. The variation in PDAS is rationalized using a coupled numerical-theoretical model as a function of local solidification conditions (thermal gradient and liquid-solid interface velocity) of the melt pool.

  1. The influence of local glucose oxidase activity on the potential/current distribution on stainless steel: A study by the wire beam electrode method

    Energy Technology Data Exchange (ETDEWEB)

    Wang Wei [Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, College of Chemistry and Chemical Engineering, Qingdao, 266100 (China)], E-mail: wwei@ouc.edu.cn; Zhang Xia [Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, College of Chemistry and Chemical Engineering, Qingdao, 266100 (China); Wang Jia [Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, College of Chemistry and Chemical Engineering, Qingdao, 266100 (China); State Key Laboratory for Corrosion and Protection, Shenyang, 110016 (China)

    2009-09-30

    The wire beam electrode (WBE) method was first used to study the activity of local glucose oxidase (GOD) on stainless steel surface in seawater. Glucose oxidase was immobilized in calcium alginate gel capsules, which were embedded in a layer of artificial biofilm (calcium alginate gel) on the WBE surface. The potential/current distributions on the WBE surface were mapped using a newly developed device for the WBE method in our lab. The results demonstrated that the catalysis of H{sub 2}O{sub 2} formation by GOD can produce local noble potential peaks and cathodic current zones on the stainless steel surface. An interesting fluctuant current distribution around cathodic zones was observed the first time. The potential and current maps showed that the enzyme heterogeneity of the artificial biofilm caused a corresponding electrochemical heterogeneity at the biofilm/metal interface. The application of the WBE method to ennoblement study enables us to observe the heterogeneous electrochemistry at biofilm/stainless steel interface directly, providing us with a powerful tool to investigate other biofilm-related processes such as microbially influenced corrosion (MIC)

  2. The influence of local glucose oxidase activity on the potential/current distribution on stainless steel: A study by the wire beam electrode method

    International Nuclear Information System (INIS)

    Wang Wei; Zhang Xia; Wang Jia

    2009-01-01

    The wire beam electrode (WBE) method was first used to study the activity of local glucose oxidase (GOD) on stainless steel surface in seawater. Glucose oxidase was immobilized in calcium alginate gel capsules, which were embedded in a layer of artificial biofilm (calcium alginate gel) on the WBE surface. The potential/current distributions on the WBE surface were mapped using a newly developed device for the WBE method in our lab. The results demonstrated that the catalysis of H 2 O 2 formation by GOD can produce local noble potential peaks and cathodic current zones on the stainless steel surface. An interesting fluctuant current distribution around cathodic zones was observed the first time. The potential and current maps showed that the enzyme heterogeneity of the artificial biofilm caused a corresponding electrochemical heterogeneity at the biofilm/metal interface. The application of the WBE method to ennoblement study enables us to observe the heterogeneous electrochemistry at biofilm/stainless steel interface directly, providing us with a powerful tool to investigate other biofilm-related processes such as microbially influenced corrosion (MIC).

  3. Assessing electron beam sensitivity for SrTiO{sub 3} and La{sub 0.7}Sr{sub 0.3}MnO{sub 3} using electron energy loss spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Nord, Magnus, E-mail: magnunor@gmail.com [Department of Physics, NTNU, Trondheim (Norway); Vullum, Per Erik [Department of Physics, NTNU, Trondheim (Norway); Materials and Chemistry, SINTEF, Trondheim (Norway); Hallsteinsen, Ingrid; Tybell, Thomas [Department of Electronics and Telecommunications, NTNU, Trondheim (Norway); Holmestad, Randi [Department of Physics, NTNU, Trondheim (Norway)

    2016-10-15

    Thresholds for beam damage have been assessed for La{sub 0.7}Sr{sub 0.3}MnO{sub 3} and SrTiO{sub 3} as a function of electron probe current and exposure time at 80 and 200 kV acceleration voltage. The materials were exposed to an intense electron probe by aberration corrected scanning transmission electron microscopy (STEM) with simultaneous acquisition of electron energy loss spectroscopy (EELS) data. Electron beam damage was identified by changes of the core loss fine structure after quantification by a refined and improved model based approach. At 200 kV acceleration voltage, damage in SrTiO{sub 3} was identified by changes both in the EEL fine structure and by contrast changes in the STEM images. However, the changes in the STEM image contrast as introduced by minor damage can be difficult to detect under several common experimental conditions. No damage was observed in SrTiO{sub 3} at 80 kV acceleration voltage, independent of probe current and exposure time. In La{sub 0.7}Sr{sub 0.3}MnO{sub 3}, beam damage was observed at both 80 and 200 kV acceleration voltages. This damage was observed by large changes in the EEL fine structure, but not by any detectable changes in the STEM images. The typical method to validate if damage has been introduced during acquisitions is to compare STEM images prior to and after spectroscopy. Quantifications in this work show that this method possibly can result in misinterpretation of beam damage as changes of material properties. - Highlights: • We studied the effects of a TEM electron beam on a perovskite heterostructure. • Using an improved ELNES quantification method, subtle changes could be observed. • On LSMO changes were observed in the ELNES, but none in the STEM-HAADF. • For STO changes were observed in both ELNES and STEM-HAADF. • This shows beam damage can be misinterpreted as material properties.

  4. A phase I study on combined therapy with proton-beam radiotherapy and in situ tumor vaccination for locally advanced recurrent hepatocellular carcinoma

    International Nuclear Information System (INIS)

    Abei, Masato; Mizumoto, Masashi; Sakae, Takeji; Sakurai, Hideyuki; Zenkoh, Junko; Ariungerel, Gerelchuluun; Sogo, Yu; Ito, Atsuo; Ohno, Tadao; Tsuboi, Koji; Okumura, Toshiyuki; Fukuda, Kuniaki; Hashimoto, Takayuki; Araki, Masahiro; Ishige, Kazunori; Hyodo, Ichinosuke; Kanemoto, Ayae; Numajiri, Haruko

    2013-01-01

    Proton-beam radiotherapy (PBT) has been shown to be effective to hepatocellular carcinoma (HCC) as a nonsurgical local treatment option. However, HCC still remains as one of the most difficult cancers to be cured because of frequent recurrences. Thus, methods to inhibit the recurrence need to be explored. To prevent the HCC recurrence, we here report on a prospective phase I study of ‘in situ’ tumor vaccination using CalTUMP, a newly developed immunoadjuvant consisting of BCG extract bound to hydroxyapatite and microparticulated tuberculin, following local PBT for HCC. Patients with locally advanced recurrent HCC, which had been heavily pretreated with various treatments, were enrolled. PBT was performed with the conventional method to the target HCC. Subsequently, CalTUMP was injected into the same irradiated-tumor three times at one-week intervals. Three dose-levels of CalTUMP (1/10, 1/3, and 1/1) were administered to 3 patients each. Vital signs, blood samples, ultrasound, and computed tomographic scans were monitored to evaluate the safety. Three intratumoral injections of CalTUMP following PBT (median dose: 72.6 GyE) were accomplished in 9 patients. Transient low-grade fever and minor laboratory changes were observed in 7 patients after CalTUMP injections. No other treatment-related adverse events were observed. Median progression-free survival was 6.0 months (range: 2.1-14.2) and 4 patients were progression-free for more than 1 year. Intratumoral injection of CalTUMP following PBT was feasible and safe in patients with heavily pre-treated HCC. Further clinical studies to evaluate the efficacy of this in situ tumor vaccination are warranted

  5. Localization of calcium in the cyanobiont and gonidial zone of Cycas revoluta Thunb. by microelectrodes, chlorotetracycline, electron spectroscopic imaging and electron energy loss spectroscopy

    International Nuclear Information System (INIS)

    Caiola, M.G.; Canini, A.; Brandizzi, F.

    1994-01-01

    Ionic calcium concentration was measured in the gonidial zone of fresh coralloid roots by means of calcium microelectrodes. It was 10 -6 M in the apical segments of coralloid roots and increased to 10 -5 M in the gonidial zones of median and basal segments. Loosely membrane-bound calcium was evidenced by using chloro-tetracycline (CTC) or ethylene glycol-bis-(β-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) and CTC, in cell walls of columnar cells of Cycas and in the cytoplasm of cyanobiont. Sub-cellular localization of calcium was obtained by electron spectroscopic imaging (ESI) and electron energy loss spectroscopy (EELS) analyses applied at transmission electron microscopy on thin, unstained sections of gonidial zone of coralloid roots. By means of these techniques, bound-calcium was detected inside the mucilage of apical and median segments whereas, in the basal segments, it was completely absent. In the heterocysts of apical segments of coralloid, calcium was localized on the envelope, cell walls, thylakoids and cyanophycin granules. In the gonidial zone of the basal segments, dead or degenerating heterocysts completely lacked calcium. Therefore, the high ionic calcium amounts detected in the gonidial zone of median and basal segments could represent a minor calcium uptake by the cells or release by lysed ones. The decreases in nitrogenase activity recorded in the median and basal segments of the coralloid roots paralleled the decrease in calcium amount in heterocyst envelope. (authors)

  6. Results of a phase II trial of external beam radiation with etanidazole (SR 2508) for the treatment of locally advanced prostate cancer (RTOG protocol 90-20)

    International Nuclear Information System (INIS)

    Lawton, Colleen A.; Coleman, C. Norman; Buzydlowski, Jan W.; Forman, Jeffrey D.; Marcial, Victor A.; DelRowe, John D.; Rotman, Marvin

    1996-01-01

    Purpose: RTOG Protocol 90-20 was designed to evaluate the effect of the hypoxic cell sensitizer Etanidazole (SR-2508) on locally advanced adenocarcinoma of the prostate treated with concurrent external beam irradiation. Methods and Materials: Patients with biopsy-proven adenocarcinoma of the prostate with locally advanced T 2b , T 3 , and T 4 tumors were eligible for this study. No patients with disease beyond the pelvis were eligible. Serum prostate specific antigen (PSA) was mandatory. All patients received definitive external beam irradiation using standard four-field whole pelvis treatment to 45-50 Gy, followed by a cone down with a minimum total dose to the prostate of 66 Gy at 1.8-2.0 Gy/fraction over 6.5-7.5 weeks. Etanidazole was delivered 1.8 g/m 2 given 3 times a week to a total of 34.2 g/m 2 or 19 doses. Results: Thirty-nine patients were entered onto the study. Three patients refused treatment; therefore, 36 patients were eligible for further evaluation. Median follow-up was 36.9 months from treatment end. All patients had elevated initial PSA levels, and 18 patients had PSAs of > 20 ng/ml. Tumor classification was T 2 , 12 patients (33.3%); T 3 , 22 patients (61.1%); and T 4 , 2 patients (5.6%). Complete clinical response, defined as PSA < 4 ng/ml and complete clinical disappearance, was attained in 17.9% of ((5(28)) pts) with information at 90 days and 56% of patients by 12 months following treatment. Relapse-free survival was 13% at 3 years with PSA < 4 ng/ml. There were no Grade 4 or 5 toxicities, either acute (during treatment) or in follow-up. Conclusions: Results of this trial regarding PSA response and clinical disappearance of disease are similar to historical controls and do not warrant further investigation of etanidazole as was done in this trial. Drug toxicity that, in the past, has been unacceptably high with other hypoxic cell sensitizers does not appear to be a significant problem with this drug

  7. Examination of the suitability of an implementation of the Jette localized heterogeneities fluence term L(1)(x,y,z) in an electron beam treatment planning algorithm

    Science.gov (United States)

    Rodebaugh, Raymond Francis, Jr.

    2000-11-01

    In this project we applied modifications of the Fermi- Eyges multiple scattering theory to attempt to achieve the goals of a fast, accurate electron dose calculation algorithm. The dose was first calculated for an ``average configuration'' based on the patient's anatomy using a modification of the Hogstrom algorithm. It was split into a measured central axis depth dose component based on the material between the source and the dose calculation point, and an off-axis component based on the physics of multiple coulomb scattering for the average configuration. The former provided the general depth dose characteristics along the beam fan lines, while the latter provided the effects of collimation. The Gaussian localized heterogeneities theory of Jette provided the lateral redistribution of the electron fluence by heterogeneities. Here we terminated Jette's infinite series of fluence redistribution terms after the second term. Experimental comparison data were collected for 1 cm thick x 1 cm diameter air and aluminum pillboxes using the Varian 2100C linear accelerator at Rush-Presbyterian- St. Luke's Medical Center. For an air pillbox, the algorithm results were in reasonable agreement with measured data at both 9 and 20 MeV. For the Aluminum pill box, there were significant discrepancies between the results of this algorithm and experiment. This was particularly apparent for the 9 MeV beam. Of course a one cm thick Aluminum heterogeneity is unlikely to be encountered in a clinical situation; the thickness, linear stopping power, and linear scattering power of Aluminum are all well above what would normally be encountered. We found that the algorithm is highly sensitive to the choice of the average configuration. This is an indication that the series of fluence redistribution terms does not converge fast enough to terminate after the second term. It also makes it difficult to apply the algorithm to cases where there are no a priori means of choosing the best average

  8. Muscle-invasive bladder cancer treated with external beam radiation: influence of total dose, overall treatment time, and treatment interruption on local control

    International Nuclear Information System (INIS)

    Moonen, L.; Voet, H. van der; Nijs, R. de; Horenblas, S.; Hart, A.A.M.; Bartelink, H.

    1998-01-01

    Purpose: To evaluate and eventually quantify a possible influence of tumor proliferation during the external radiation course on local control in muscle invasive bladder cancer. Methods and Materials: The influence of total dose, overall treatment time, and treatment interruption has retrospectively been analyzed in a series of 379 patients with nonmetastasized, muscle-invasive transitional cell carcinoma of the urinary bladder. All patients received external beam radiotherapy at the Netherlands Cancer Institute between 1977 and 1990. Total dose varied between 50 and 75 Gy with a mean of 60.5 Gy and a median of 60.4 Gy. Overall treatment time varied between 20 and 270 days with a mean of 49 days and a median of 41 days. Number of fractions varied between 17 and 36 with a mean of 27 and a median of 26. Two hundred and forty-four patients had a continuous radiation course, whereas 135 had an intended split course or an unintended treatment interruption. Median follow-up was 22 months for all patients and 82 months for the 30 patients still alive at last follow-up. A stepwise procedure using proportional hazard regression has been used to identify prognostic treatment factors with respect to local recurrence as sole first recurrence. Results: One hundred and thirty-six patients experienced a local recurrence and 120 of these occurred before regional or distant metastases. The actuarial local control rate was 40.3% at 5 years and 32.3% at 10 years. In a multivariate analysis total dose showed a significant association with local control (p 0.0039), however in a markedly nonlinear way. In fact only those patients treated with a dose below 57.5 Gy had a significant higher bladder relapse rate, whereas no difference in relapse rate was found among patients treated with doses above 57.5 Gy. This remained the case even after adjustment for overall treatment time and all significant tumor and patient characteristics. The Normalized Tumor Dose (NTD) (α/β = 10) and NTD (

  9. Combined modality therapy for localized prostate carcinoma using Iridium-192 brachytherapy and external beam radiotherapy: results, morbidity, and the lack of value of surgical lymph node staging

    International Nuclear Information System (INIS)

    Baird, Michael; Ordorica, Edward; Dawson, Anne

    1997-01-01

    Purpose/Objective: (1) To quantitate the morbidity and 5 and 10 year bNED survival of Ir-192 temporary implant combined with external beam radiotherapy in the treatment of clinically localized Prostate Carcinoma. (2) To determine the need for nodal staging prior to implant. Materials and Methods: 335 consecutively treated patients seen between 8/17/84 and 8/13/93 were analyzed. All patents had retropertoneal nodal dissection and were implanted with Ir-192 using the Syed-Neblett template. Thirteen percent who completed treatment per protocol were found to have microscopically involved nodes on permanent section. 277 patients had completed the entire treatment protocol and had at least 2 years follow-up with DRE and serial serum PSAs. All patients were evaluated for morbidity using the standard RTOG morbidity scales. The bNED survival was determined using Kaplan-Meier methods with a non-rising PSA value of < 1.0 used as an indicator of disease control. All patients received 30 Gy in 50 hrs. to the implant volume, followed in two weeks by 34.2 Gy external beam (19 fx/ 25 days). The median follow up for the group is 55 months. Results: Morbidity: 69.2% of the patients experienced no reportable morbidity. Urinary morbidity was usually transient and mild (Grade 1 or 2 in 9.7%). 4.9 % experienced grade 3 urinary complaints (6.6% stress incontinence) and the incidence of grade 4 urinary complaints was 0.6%. Urinary complications were 2.5 times more common in patients who had previously undergone a TURP. Rectal complications were mild or moderate in 10.5% and usually consisted of asymptomatic rectal bleeding (6.9%). Severe rectal ulcer requiring temporary colostomy occurred in 1.4% and always healed after colostomy. Other morbidity consisted of mild, self-limited edema (2.1%). One patient had persistent edema post treatment, and there was one death from a CVA perioperatively (0.3%). 75% of patients who were potent prior to treatment maintained useful sexual function post

  10. Comparison of panoramic radiography and cone-beam computed tomography for qualitative and quantitative measurements regarding localization of permanent impacted maxillary canines

    Directory of Open Access Journals (Sweden)

    Çiğdem Sarıkır

    2017-01-01

    Full Text Available Objective: The purpose of this retrospective study was to compare the correlation between digital panoramic radiography (DPR and cone-beam computed tomography (CBCT evaluations for localization of impacted permanent maxillary canines (IPMCs and for other qualitative and quantitative parameters. Materials and Method: DPR and CBCT images of 60 patients (17 men and 43 women were examined independently by two observers. Correlations between DPR and CBCT images were evaluated regarding qualitative (bucco-palatal positioning of IPMCs, morphology and presence of root resorption of adjacent permanent lateral incisors, and contact relationship between IPMCs and adjacent permanent lateral incisors and quantitative (angle measurements variables. All evaluations were repeated 1 month later by each observer. Chi-square and t-tests were used for statistical analysis. Kappa statistics were used to assess intra- and interobserver agreement (Cohen’s κ. Results: No correlation was observed for determination of bucco-palatal positioning of IPMCs between DPR and CBCT images (p>0.05. Correlations were observed for other qualitative variables (p<0.05. Differences between DPR and CBCT images were seen for all examined quantitative variables (p<0.01. Intra- and interobserver agreements were substantial to almost-perfect. Conclusion: No significant correlation was found between DPR and CBCT images for determination of bucco-palatal positioning of IPMCs. All quantitative measurements performed on DPR and CBCT images significantly differed from each other.

  11. Electron-beam-induced current measurements with applied bias provide insight to locally resolved acceptor concentrations at p-n junctions

    Directory of Open Access Journals (Sweden)

    D. Abou-Ras

    2015-07-01

    Full Text Available Electron-beam-induced current (EBIC measurements have been employed for the investigation of the local electrical properties existing at various types of electrical junctions during the past decades. In the standard configuration, the device under investigation is analyzed under short-circuit conditions. Further insight into the function of the electrical junction can be obtained when applying a bias voltage. The present work gives insight into how EBIC measurements at applied bias can be conducted at the submicrometer level, at the example of CuInSe2 solar cells. From the EBIC profiles acquired across ZnO/CdS/CuInSe2/Mo stacks exhibiting p-n junctions with different net doping densities in the CuInSe2 layers, values for the width of the space-charge region, w, were extracted. For all net doping densities, these values decreased with increasing applied voltage. Assuming a linear relationship between w2 and the applied voltage, the resulting net doping densities agreed well with the ones obtained by means of capacitance-voltage measurements.

  12. Hemoglobin levels do not predict biochemical outcome for localized prostate cancer treated with neoadjuvant androgen-suppression therapy and external-beam radiotherapy

    International Nuclear Information System (INIS)

    Pai, Howard Huaihan; Ludgate, Charles; Pickles, Tom; Paltiel, Chuck M.Sc.; Agranovich, Alex; Berthelet, Eric; Duncan, Graeme; Kim-Sing, Charmaine; Kwan, Winkle; Lim, Jan; Liu, Mitchell; Tyldesley, Scott

    2006-01-01

    Purpose: To investigate whether hemoglobin (Hb) levels affect outcome in men with localized prostate adenocarcinoma (LPA) treated with neoadjuvant androgen-suppression therapy (NAST) and external-beam radiotherapy (EBRT). Methods and Materials: A total of 563 men with LPA treated with NAST (median: 5.3 months) and EBRT who had Hb levels during treatment were retrospectively reviewed. Patient, tumor, and treatment variables, including the following Hb variables, were subjected to univariate and multivariable analyses to identify factors that predict biochemical control (bNED) and overall survival (OS): pre-EBRT Hb, Hb nadir during EBRT, and change in Hb from pre-EBRT to nadir during EBRT. Results: Median PSA follow-up was 4.25 years. Forty-nine percent of men were anemic during EBRT, with a median Hb of 13.4 g/dL, and 68% experienced a decline in Hb from pre-EBRT to during EBRT of median 0.6 g/dL. Five-year Nadir + 2 bNED and OS rates were similar for anemic and nonanemic patients during EBRT. High percent-positive biopsies, PSA and Gleason score, and use of AA monotherapy predicted worse bNED. High stage and age predicted worse OS. Hb variables were not predictive of bNED or OS. Conclusions: Anemia is a common side effect of NAST and is usually mild. Hb levels, however, do not predict biochemical control or survival

  13. Observability of localized magnetoplasmons in quantum dots: Scrutinizing the eligibility of far-infrared, Raman, and electron-energy-loss spectroscopies

    Directory of Open Access Journals (Sweden)

    Manvir S. Kushwaha

    2016-03-01

    Full Text Available We investigate a one-component, quasi-zero dimensional, quantum plasma exposed to a parabolic potential and an applied magnetic field in the symmetric gauge. If the size of such a system as can be realized in the semiconducting quantum dots is on the order of the de-Broglie wavelength, the electronic and optical properties become highly tunable. Then the quantum size effects challenge the observation of many-particle phenomena such as the magneto-optical absorption, Raman intensity, and electron energy-loss spectrum. An exact analytical solution of the problem leads us to infer that these many-particle phenomena are, in fact, dictated by the generalized Kohn’s theorem (GKT in the long-wavelength limit. Maneuvering the confinement and/or the magnetic field furnishes the resonance energies capable of being explored with the FIR, Raman, and/or electron-energy-loss spectroscopy. This implies that either of these probes is competent in observing the localized magnetoplasmons in the system. As an application of the rigorous analytical diagnosis of the system, we have presented various pertinent single-particle, such as Fock-Darwin spectrum, Fermi energy, zigzag excitation spectrum, and magneto-optical transitions, and the many-particle phenomena, such as magneto-optical absorption, Raman intensity, and electron energy-loss probability. In the latter, the energy position of the resonance peaks is observed to be independent of the electron-electron interactions and hence of the number of electrons in the quantum dot in compliance with the GKT. It is found that both confinement potential and magnetic field play a decisive role in influencing the aforementioned many-particle phenomena. Specifically, increasing (decreasing the strength of the confining potential is found to be analogous to shrinking (expanding the size of the quantum dots and results into a blue (red shift in the respective spectra. Intensifying the magnetic field has two-fold effects in

  14. Loss of Nuclear Localized and Tyrosine Phosphorylated Stat5 in Breast Cancer Predicts Poor Clinical Outcome and Increased Risk of Antiestrogen Therapy Failure

    Science.gov (United States)

    Peck, Amy R.; Witkiewicz, Agnieszka K.; Liu, Chengbao; Stringer, Ginger A.; Klimowicz, Alexander C.; Pequignot, Edward; Freydin, Boris; Tran, Thai H.; Yang, Ning; Rosenberg, Anne L.; Hooke, Jeffrey A.; Kovatich, Albert J.; Nevalainen, Marja T.; Shriver, Craig D.; Hyslop, Terry; Sauter, Guido; Rimm, David L.; Magliocco, Anthony M.; Rui, Hallgeir

    2011-01-01

    Purpose To investigate nuclear localized and tyrosine phosphorylated Stat5 (Nuc-pYStat5) as a marker of prognosis in node-negative breast cancer and as a predictor of response to antiestrogen therapy. Patients and Methods Levels of Nuc-pYStat5 were analyzed in five archival cohorts of breast cancer by traditional diaminobenzidine-chromogen immunostaining and pathologist scoring of whole tissue sections or by immunofluorescence and automated quantitative analysis (AQUA) of tissue microarrays. Results Nuc-pYStat5 was an independent prognostic marker as measured by cancer-specific survival (CSS) in patients with node-negative breast cancer who did not receive systemic adjuvant therapy, when adjusted for common pathology parameters in multivariate analyses both by standard chromogen detection with pathologist scoring of whole tissue sections (cohort I; n = 233) and quantitative immunofluorescence of a tissue microarray (cohort II; n = 291). Two distinct monoclonal antibodies gave concordant results. A progression array (cohort III; n = 180) revealed frequent loss of Nuc-pYStat5 in invasive carcinoma compared to normal breast epithelia or ductal carcinoma in situ, and general loss of Nuc-pYStat5 in lymph node metastases. In cohort IV (n = 221), loss of Nuc-pYStat5 was associated with increased risk of antiestrogen therapy failure as measured by univariate CSS and time to recurrence (TTR). More sensitive AQUA quantification of Nuc-pYStat5 in antiestrogen-treated patients (cohort V; n = 97) identified by multivariate analysis patients with low Nuc-pYStat5 at elevated risk for therapy failure (CSS hazard ratio [HR], 21.55; 95% CI, 5.61 to 82.77; P < .001; TTR HR, 7.30; 95% CI, 2.34 to 22.78; P = .001). Conclusion Nuc-pYStat5 is an independent prognostic marker in node-negative breast cancer. If confirmed in prospective studies, Nuc-pYStat5 may become a useful predictive marker of response to adjuvant hormone therapy. PMID:21576635

  15. Observability of localized magnetoplasmons in quantum dots: Scrutinizing the eligibility of far-infrared, Raman, and electron-energy-loss spectroscopies

    Energy Technology Data Exchange (ETDEWEB)

    Kushwaha, Manvir S. [Department of Physics and Astronomy, Rice University, P.O. Box 1892, Houston, Texas 77251 (United States)

    2016-03-15

    We investigate a one-component, quasi-zero dimensional, quantum plasma exposed to a parabolic potential and an applied magnetic field in the symmetric gauge. If the size of such a system as can be realized in the semiconducting quantum dots is on the order of the de-Broglie wavelength, the electronic and optical properties become highly tunable. Then the quantum size effects challenge the observation of many-particle phenomena such as the magneto-optical absorption, Raman intensity, and electron energy-loss spectrum. An exact analytical solution of the problem leads us to infer that these many-particle phenomena are, in fact, dictated by the generalized Kohn’s theorem (GKT) in the long-wavelength limit. Maneuvering the confinement and/or the magnetic field furnishes the resonance energies capable of being explored with the FIR, Raman, and/or electron-energy-loss spectroscopy. This implies that either of these probes is competent in observing the localized magnetoplasmons in the system. As an application of the rigorous analytical diagnosis of the system, we have presented various pertinent single-particle, such as Fock-Darwin spectrum, Fermi energy, zigzag excitation spectrum, and magneto-optical transitions, and the many-particle phenomena, such as magneto-optical absorption, Raman intensity, and electron energy-loss probability. In the latter, the energy position of the resonance peaks is observed to be independent of the electron-electron interactions and hence of the number of electrons in the quantum dot in compliance with the GKT. It is found that both confinement potential and magnetic field play a decisive role in influencing the aforementioned many-particle phenomena. Specifically, increasing (decreasing) the strength of the confining potential is found to be analogous to shrinking (expanding) the size of the quantum dots and results into a blue (red) shift in the respective spectra. Intensifying the magnetic field has two-fold effects in the resonance

  16. Robust sampling-sourced numerical retrieval algorithm for optical energy loss function based on log–log mesh optimization and local monotonicity preserving Steffen spline

    Energy Technology Data Exchange (ETDEWEB)

    Maglevanny, I.I., E-mail: sianko@list.ru [Volgograd State Social Pedagogical University, 27 Lenin Avenue, Volgograd 400131 (Russian Federation); Smolar, V.A. [Volgograd State Technical University, 28 Lenin Avenue, Volgograd 400131 (Russian Federation)

    2016-01-15

    We introduce a new technique of interpolation of the energy-loss function (ELF) in solids sampled by empirical optical spectra. Finding appropriate interpolation methods for ELFs poses several challenges. The sampled ELFs are usually very heterogeneous, can originate from various sources thus so called “data gaps” can appear, and significant discontinuities and multiple high outliers can be present. As a result an interpolation based on those data may not perform well at predicting reasonable physical results. Reliable interpolation tools, suitable for ELF applications, should therefore satisfy several important demands: accuracy and predictive power, robustness and computational efficiency, and ease of use. We examined the effect on the fitting quality due to different interpolation schemes with emphasis on ELF mesh optimization procedures and we argue that the optimal fitting should be based on preliminary log–log scaling data transforms by which the non-uniformity of sampled data distribution may be considerably reduced. The transformed data are then interpolated by local monotonicity preserving Steffen spline. The result is a piece-wise smooth fitting curve with continuous first-order derivatives that passes through all data points without spurious oscillations. Local extrema can occur only at grid points where they are given by the data, but not in between two adjacent grid points. It is found that proposed technique gives the most accurate results and also that its computational time is short. Thus, it is feasible using this simple method to address practical problems associated with interaction between a bulk material and a moving electron. A compact C++ implementation of our algorithm is also presented.

  17. Robust sampling-sourced numerical retrieval algorithm for optical energy loss function based on log–log mesh optimization and local monotonicity preserving Steffen spline

    International Nuclear Information System (INIS)

    Maglevanny, I.I.; Smolar, V.A.

    2016-01-01

    We introduce a new technique of interpolation of the energy-loss function (ELF) in solids sampled by empirical optical spectra. Finding appropriate interpolation methods for ELFs poses several challenges. The sampled ELFs are usually very heterogeneous, can originate from various sources thus so called “data gaps” can appear, and significant discontinuities and multiple high outliers can be present. As a result an interpolation based on those data may not perform well at predicting reasonable physical results. Reliable interpolation tools, suitable for ELF applications, should therefore satisfy several important demands: accuracy and predictive power, robustness and computational efficiency, and ease of use. We examined the effect on the fitting quality due to different interpolation schemes with emphasis on ELF mesh optimization procedures and we argue that the optimal fitting should be based on preliminary log–log scaling data transforms by which the non-uniformity of sampled data distribution may be considerably reduced. The transformed data are then interpolated by local monotonicity preserving Steffen spline. The result is a piece-wise smooth fitting curve with continuous first-order derivatives that passes through all data points without spurious oscillations. Local extrema can occur only at grid points where they are given by the data, but not in between two adjacent grid points. It is found that proposed technique gives the most accurate results and also that its computational time is short. Thus, it is feasible using this simple method to address practical problems associated with interaction between a bulk material and a moving electron. A compact C++ implementation of our algorithm is also presented.

  18. A multi-component evaporation model for beam melting processes

    Science.gov (United States)

    Klassen, Alexander; Forster, Vera E.; Körner, Carolin

    2017-02-01

    In additive manufacturing using laser or electron beam melting technologies, evaporation losses and changes in chemical composition are known issues when processing alloys with volatile elements. In this paper, a recently described numerical model based on a two-dimensional free surface lattice Boltzmann method is further developed to incorporate the effects of multi-component evaporation. The model takes into account the local melt pool composition during heating and fusion of metal powder. For validation, the titanium alloy Ti-6Al-4V is melted by selective electron beam melting and analysed using mass loss measurements and high-resolution microprobe imaging. Numerically determined evaporation losses and spatial distributions of aluminium compare well with experimental data. Predictions of the melt pool formation in bulk samples provide insight into the competition between the loss of volatile alloying elements from the irradiated surface and their advective redistribution within the molten region.

  19. Beam diagnostics for low energy beams

    Directory of Open Access Journals (Sweden)

    J. Harasimowicz

    2012-12-01

    Full Text Available Low-energetic ion and antimatter beams are very attractive for a number of fundamental studies. The diagnostics of such beams, however, is a challenge due to low currents down to only a few thousands of particles per second and significant fraction of energy loss in matter at keV beam energies. A modular set of particle detectors has been developed to suit the particular beam diagnostic needs of the ultralow-energy storage ring (USR at the future facility for low-energy antiproton and ion research, accommodating very low beam intensities at energies down to 20 keV. The detectors include beam-profile monitors based on scintillating screens and secondary electron emission, sensitive Faraday cups for absolute intensity measurements, and capacitive pickups for beam position monitoring. In this paper, the design of all detectors is presented in detail and results from beam measurements are shown. The resolution limits of all detectors are described and options for further improvement summarized. Whilst initially developed for the USR, the instrumentation described in this paper is also well suited for use in other low-intensity, low-energy accelerators, storage rings, and beam lines.

  20. Localizing intracavitary brachytherapy applicators from cone-beam CT x-ray projections via a novel iterative forward projection matching algorithm

    International Nuclear Information System (INIS)

    Pokhrel, Damodar; Murphy, Martin J.; Todor, Dorin A.; Weiss, Elisabeth; Williamson, Jeffrey F.

    2011-01-01

    Purpose: To present a novel method for reconstructing the 3D pose (position and orientation) of radio-opaque applicators of known but arbitrary shape from a small set of 2D x-ray projections in support of intraoperative brachytherapy planning. Methods: The generalized iterative forward projection matching (gIFPM) algorithm finds the six degree-of-freedom pose of an arbitrary rigid object by minimizing the sum-of-squared-intensity differences (SSQD) between the computed and experimentally acquired autosegmented projection of the objects. Starting with an initial estimate of the object's pose, gIFPM iteratively refines the pose parameters (3D position and three Euler angles) until the SSQD converges. The object, here specialized to a Fletcher-Weeks intracavitary brachytherapy (ICB) applicator, is represented by a fine mesh of discrete points derived from complex combinatorial geometric models of the actual applicators. Three pairs of computed and measured projection images with known imaging geometry are used. Projection images of an intrauterine tandem and colpostats were acquired from an ACUITY cone-beam CT digital simulator. An image postprocessing step was performed to create blurred binary applicators only images. To quantify gIFPM accuracy, the reconstructed 3D pose of the applicator model was forward projected and overlaid with the measured images and empirically calculated the nearest-neighbor applicator positional difference for each image pair. Results: In the numerical simulations, the tandem and colpostats positions (x,y,z) and orientations (α,β,γ) were estimated with accuracies of 0.6 mm and 2 deg., respectively. For experimentally acquired images of actual applicators, the residual 2D registration error was less than 1.8 mm for each image pair, corresponding to about 1 mm positioning accuracy at isocenter, with a total computation time of less than 1.5 min on a 1 GHz processor. Conclusions: This work describes a novel, accurate, fast, and completely

  1. Prospective Phase II Study of Brachytherapy Boost as a Component of Neo-Adjuvant Chemotherapy and External Beam Radiation Therapy in Locally Advanced Rectal Cancer

    International Nuclear Information System (INIS)

    EL-SAYED, M.E.; EL-TAHER, Z.H.

    2008-01-01

    The aim of the current study is to assess the response rate and toxicity profile in patients with locally advanced rectal cancer using brachytherapy (BT) boost following external beam radiotherapy (EBRT), concomitant with chemotherapy as a component of the neoadjuvant treatment. Patients and Methods: This is a prospective phase II study of neoadjuvant chemo-radiation therapy for patients with locally advanced rectal cancer who presented to the department of radiation oncology, King Abdul-Aziz University Hospital, Jeddah, Kingdom of Saudi Arabia. Seventeen patients had been included in the study. Radiation therapy was given as: phase I,45 Gy/25 fractions/5 weeks of EBRT, followed by brachytherapy boost (within one week after the end of EBRT) using high dose rate iridium 192 (Ir 192 ) aiming at 800 c Gy given in 2 fractions (each 400 c Gy) separated by 1 week. All patients received the same concomitant chemotherapy in the form of Capecitabine and Oxaliplatin. The clinical and pathological response rates, together with the toxicity profile were assessed. Results: Seventeen patients had been studied; the majority (14; 82%) were males, while 3 only (18%) were females, their mean age was 57.4 years. All patients had low anterior resection (LAR). The clinical response rate, assessed by digital rectal examination ± endoscopy examination 4 weeks after the end of EBRT and BT, revealed that complete clinical response (cCR) was noted in 3 patients (18%), clinical partial response (cPR) in 14 patients (82%); while the pathological response rate was: complete pathological response (pCR) in 8 patients (47%), pathological partial response (pPR) in 9 patients (53%). The toxicity profile showed that grade III radiation proctitis was seen in one patient (6%), grade III dermatitis in 2 (12%), while no patients developed grade III cystitis. For chemotherapy toxicities, three patients (18%) developed grade III nausea and/or vomiting, 2 (12%) developed grade III diarrhea. Conclusion

  2. Localizing intracavitary brachytherapy applicators from cone-beam CT x-ray projections via a novel iterative forward projection matching algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Pokhrel, Damodar; Murphy, Martin J.; Todor, Dorin A.; Weiss, Elisabeth; Williamson, Jeffrey F. [Department of Radiation Oncology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia 23298 (United States)

    2011-02-15

    Purpose: To present a novel method for reconstructing the 3D pose (position and orientation) of radio-opaque applicators of known but arbitrary shape from a small set of 2D x-ray projections in support of intraoperative brachytherapy planning. Methods: The generalized iterative forward projection matching (gIFPM) algorithm finds the six degree-of-freedom pose of an arbitrary rigid object by minimizing the sum-of-squared-intensity differences (SSQD) between the computed and experimentally acquired autosegmented projection of the objects. Starting with an initial estimate of the object's pose, gIFPM iteratively refines the pose parameters (3D position and three Euler angles) until the SSQD converges. The object, here specialized to a Fletcher-Weeks intracavitary brachytherapy (ICB) applicator, is represented by a fine mesh of discrete points derived from complex combinatorial geometric models of the actual applicators. Three pairs of computed and measured projection images with known imaging geometry are used. Projection images of an intrauterine tandem and colpostats were acquired from an ACUITY cone-beam CT digital simulator. An image postprocessing step was performed to create blurred binary applicators only images. To quantify gIFPM accuracy, the reconstructed 3D pose of the applicator model was forward projected and overlaid with the measured images and empirically calculated the nearest-neighbor applicator positional difference for each image pair. Results: In the numerical simulations, the tandem and colpostats positions (x,y,z) and orientations ({alpha},{beta},{gamma}) were estimated with accuracies of 0.6 mm and 2 deg., respectively. For experimentally acquired images of actual applicators, the residual 2D registration error was less than 1.8 mm for each image pair, corresponding to about 1 mm positioning accuracy at isocenter, with a total computation time of less than 1.5 min on a 1 GHz processor. Conclusions: This work describes a novel, accurate

  3. Localizing intracavitary brachytherapy applicators from cone-beam CT x-ray projections via a novel iterative forward projection matching algorithm.

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