WorldWideScience

Sample records for beam position

  1. Beam Position Monitoring at CLIC

    CERN Document Server

    Prochnow, J

    2003-01-01

    At the European Organisation for Nuclear Research CERN in Geneva, Switzerland the design of the Compact LInear Collider (CLIC) for high energy physics is studied. To achieve the envisaged high luminosity the quadrupole magnets and radio-frequency accelerating structures have to be actively aligned with micron precision and submicron resolution. This will be done using beam-based algorithms which rely on beam position information inside of quadrupoles and accelerating structures. After a general introduction to the CLIC study and the alignment algorithms, the concept of the interaction between beams and radio-frequency structures is given. In the next chapter beam measurements and simulations are described which were done to study the performance of cavity beam position monitors (BPM). A BPM design is presented which is compatible with the multi-bunch operation at CLIC and could be used to align the quadrupoles. The beam position inside the accelerating structures will be measured by using the structures thems...

  2. Libera Electron Beam Position Processor

    CERN Document Server

    Ursic, Rok

    2005-01-01

    Libera is a product family delivering unprecedented possibilities for either building powerful single station solutions or architecting complex feedback systems in the field of accelerator instrumentation and controls. This paper presents functionality and field performance of its first member, the electron beam position processor. It offers superior performance with multiple measurement channels delivering simultaneously position measurements in digital format with MHz kHz and Hz bandwidths. This all-in-one product, facilitating pulsed and CW measurements, is much more than simply a high performance beam position measuring device delivering micrometer level reproducibility with sub-micrometer resolution. Rich connectivity options and innate processing power make it a powerful feedback building block. By interconnecting multiple Libera electron beam position processors one can build a low-latency high throughput orbit feedback system without adding additional hardware. Libera electron beam position processor ...

  3. Electrostatic beam-position monitor

    CERN Multimedia

    CERN PhotoLab

    1969-01-01

    Electrostatic beam-position monitor installed in its final location (bake-out cover removed). The ISR will contain about 110 of these monitors. Their accuracy is better than 1 mm, their band width about 1 MHz.

  4. LEDA BEAM DIAGNOSTICS INSTRUMENTATION: BEAM POSITION MONITORS

    International Nuclear Information System (INIS)

    The Low Energy Demonstration Accelerator (LEDA) facility located at Los Alamos National Laboratory (LANL) accelerates protons to an energy of 6.7-MeV and current of 100-mA operating in either a pulsed or cw mode. Of key importance to the commissioning and operations effort is the Beam Position Monitor system (BPM). The LEDA BPM system uses five micro-stripline beam position monitors processed by log ratio processing electronics with data acquisition via a series of custom TMS32OC40 Digital Signal Processing (DSP) boards. Of special interest to this paper is the operation of the system, the log ratio processing, and the system calibration technique. This paper will also cover the DSP system operations and their interaction with the main accelerator control system

  5. Antiproton source beam position system

    International Nuclear Information System (INIS)

    The TeV I Beam Position Monitor (BPM) system is designed to provide a useful diagnostic tool during the commissioning and operational phases of the antiproton source. Simply stated the design goal is to provide single turn position information for intensities of > 1x109 particles, and multi-turn (clocked orbit) information for beam intensities of > 1x107 particles, both with sub-millimeter resolution. It is anticipated that the system will be used during commissioning for establishing the first turn through the Debuncher and Accumulator, for aligning injection orbits, for providing information necessary to correct closed orbits, and for measuring various machine parameters (e.g. tunes, dispersion, aperture, chromaticity). During normal antiproton operation the system will be used to monitor the beam position throughout the accumulation process

  6. Tevatron Beam Position Monitor Upgrade

    CERN Document Server

    Wolbers, Stephen; Barker, B; Bledsoe, S; Boes, T; Bowden, Mark; Cancelo, Gugstavo I; Dürling, G; Forster, B; Haynes, B; Hendricks, B; Kasza, T; Kutschke, Robert K; Mahlum, R; Martens, Michael A; Mengel, M; Olsen, M; Pavlicek, V; Pham, T; Piccoli, Luciano; Steimel, Jim; Treptow, K; Votava, Margaret; Webber, Robert C; West, B; Zhang, D

    2005-01-01

    The Tevatron Beam Position Monitor (BPM) readout electronics and software have been upgraded to improve measurement precision, functionality and reliability. The original system, designed and built in the early 1980s, became inadequate for current and future operations of the Tevatron. The upgraded system consists of 960 channels of new electronics to process analog signals from 240 BPMs, new front-end software, new online and controls software, and modified applications to take advantage of the improved measurements and support the new functionality. The new system reads signals from both ends of the existing directional stripline pickups to provide simultaneous proton and antiproton position measurements. Measurements using the new system are presented that demonstrate its improved resolution and overall performance.

  7. Calibration of waveguide beam position monitors

    CERN Document Server

    Kamps, T

    2000-01-01

    To ensure overlap between the photon beam and electron beam at the SASE-FEL at the TESLA Test Facility, several position-sensitive diagnostics components are installed along the beamline of the FEL. For the undulator part, a new type of waveguide beam position monitors (BPMs) is designed, tested, and installed inside the beam pipe of one undulator module. This paper proposes a method to calibrate these monitors with beam-based measurements

  8. Transverse Beam Size Effects in Beam Position Monitors

    Science.gov (United States)

    Kurennoy, Sergey

    2001-04-01

    The fields produced by a long beam with a given transverse charge distribution in a homogeneous vacuum chamber are studied. Signals induced by the displaced finite-size beam on electrodes of a beam position monitor (BPM) are calculated and compared to those from a pencil beam. The corrections to BPM signals due to a finite beam size are found analytically for a few particular transverse distributions of the beam current. The results for fields can also be directly applied for calculating the beam coupling impedances of small discontinuities.

  9. The Electro-Optic Beam Position Monitor

    CERN Document Server

    Doherty, James

    2013-01-01

    This reports outlines the development of a new ultra-wideband electro-optic beam position monitor (EO-BPM) for use in the Large Hadron Collider (LHC) which utilises birefringent crystals and the Pockels effect to monitor beam position. The physical principles behind the operation of the device and tested topology, which incorporates two Lithium Tantalate crystals, is discussed.

  10. Effects of Transverse Beam Size in Beam Position Monitors

    CERN Document Server

    Kurennoy, S S

    2001-01-01

    The fields produced by a long beam with a given transverse charge distribution in a homogeneous vacuum chamber are studied. Signals induced by a displaced finite-size beam on electrodes of a beam position monitor (BPM) are calculated and compared to those produced by a pencil beam. The non-linearities and corrections to BPM signals due to a finite transverse beam size are calculated for an arbitrary chamber cross section. Simple analytical expressions are given for a few particular transverse distributions of the beam current in a circular or rectangular chamber. Of particular interest is a general proof that in an arbitrary homogeneous chamber the beam-size corrections vanish for any axisymmetric beam current distribution.

  11. Effects of transverse beam size in beam position monitors.

    Energy Technology Data Exchange (ETDEWEB)

    Kurennoy, S. (Sergey)

    2001-01-01

    The fields produced by a long beam with a given transverse charge distribution in a homogeneous vacuum chamber are studied. Signals induced by the displaced finite-size beam on electrodes of a beam position monitor (BPM) are calculated and compared to those from a pencil beam. The non-linearities and corrections to BPM signals due to a finite transverse beam size are calculated for an arbitrary chamber cross section. Simple analytical expressions are given for a few particular transverse distributions of the beam current in a circular or rectangular chamber. Of particular interest is a general proof that in an arbitrary homogeneous chamber the beam-size corrections vanish for any axisymmetric beam current distribution.

  12. EFFECTS OF TRANSFERSE BEAM SIZE IN BEAM POSITIONS MONITORS

    Energy Technology Data Exchange (ETDEWEB)

    S.S. KURENNOY

    2001-06-01

    The fields produced by a long beam with a given transverse charge distribution in a homogeneous vacuum chamber are studied. Signals induced by the displaced finite-size beam on electrodes of a beam position monitor (BPM) are calculated and compared to those from a pencil beam. The non-linearities and corrections to BPM signals due to a finite transverse beam size are calculated for an arbitrary chamber cross section. Simple analytical expressions are given for a few particular transverse distributions of the beam current in a circular or rectangular chamber. Of particular interest is a general proof that in an arbitrary homogeneous chamber the beam-size corrections vanish for any axisymmetric beam current distribution.

  13. Resolving Two Beams in Beam Splitters with a Beam Position Monitor

    CERN Document Server

    Kurennoy, S S

    2002-01-01

    The beam transport system for the Advanced Hydrotest Facility (AHF) anticipates multiple beam splitters [1]. Monitoring two separated beams in a common beam pipe in the splitter sections imposes certain requirements on diagnostics for these sections. In this note we explore a two-beam system in a generic beam monitor and study the feasibility of resolving the positions of the two beams with a single diagnostic device.

  14. Resolving Two Beams in Beam Splitters with a Beam Position Monitor

    Science.gov (United States)

    Kurennoy, Sergey

    2002-04-01

    The beam transport system for the Advanced Hydrotest Facility (AHF) anticipates multiple beam splitters. Monitoring two transversely separated beams in a common beam pipe in the splitter sections imposes certain requirements on beam diagnostics for these sections. We explore a two-beam system in a generic beam monitor and study the feasibility of resolving the transverse positions of the two beams with one diagnostics device. Effects of unequal beam currents and of finite transverse sizes of the beams are explored analytically for both the ultra relativistic case and the long-wavelength limit.

  15. Laser Wire and Beam Position Monitor tests

    CERN Document Server

    Boogert, S T; Lyapin, A; Nevay, L; Snuverink, J

    2013-01-01

    This subtask involved two main activities; Firstly the development and subsequent usage of high resolution beam position monitors (BPM) for the International Linear Collider (ILC) and Compact Linear Collider projects (CLIC); and secondly the development of a laser-wire (LW) transverse beam size measurement systems. This report describes the technical progress achieved at a large-scale test ILC compatible BPM system installed at the Accelerator Test Facility 2 (ATF2). The ATF2 is an energy-scaled demonstration system for the final focus systems required to deliver the particle beams to collision at the ILC and CLIC. The ATF2 cavity beam position monitor system is one of the largest of its kind and rivals systems used at free electron lasers. The ATF2 cavity beam position system has achieved a position resolutionof 250 nm (with signal attuenation) and 27 nm (without attenuation). The BPM system has been used routinely for lattice diagnostics, beam based alignment and wakefield measurements. Extensive experience...

  16. Positive solutions for nonlinear elastic beam models

    OpenAIRE

    Bendong Lou

    2001-01-01

    We give a negative answer to a conjecture of Korman on nonlinear elastic beam models. Moreover, by modifying the main conditions in the conjecture (generalizing the original ones at some points), we get positive results, that is, we obtain the existence of positive solutions for the models.

  17. Beam position measurements of Indus-2 using X-Ray beam position monitor

    International Nuclear Information System (INIS)

    A staggered pair metal blade X-ray beam position monitor (XBPM) is designed, fabricated and commissioned on Indus-2 bending magnet front end. Calibration of XBPM is done by scanning the metal blades in the path of synchrotron radiation and by giving controlled electron asymmetric bump. The vertical beam position stability of the source measured during various injections and storages are reported.

  18. Signal processing for beam position measurement

    CERN Document Server

    Vos, L

    1997-01-01

    The spectrum of the signals generated by beam position monitors can be very large. It is the convolution product of the bunch spectrum and the transfer function of the monitor including the transmission cable. The rate of information flow is proportional to the bandwidth and the maximum amplitude rating of monitor complex. Technology is progressing at a good pace and modern acquisition capabilities are such that nearly all the information contained in the spectrum can be acquired with a reasonable resolution [1]. However, the cost of such a system is enormous and a major part of the information is superfluous. The objective of a beam position measurement system is generally restricted to trajectory measurements of a portion of the beam that is much larger than the finer details that can be observed with the bare signal generated by the position monitor. Closed orbit measurements are a simple derivation product of the trajectory and will not be considered further. The smallest beam portion that is of practical...

  19. Resolving two beams in beam splitters with a beam position monitor

    Energy Technology Data Exchange (ETDEWEB)

    Kurennoy, S. (Sergey)

    2002-01-01

    The beam transport system for the Advanced Hydrotest Facility (AHF) anticipates multiple beam splitters. Monitoring two separated beams in a common beam pipe in the splitter sections imposes certain requirements on diagnostics for these sections. In this note we explore a two-beam system in a generic beam monitor and study the feasibility of resolving the positions of the two beams with a single diagnostic device. In the Advanced Hydrotest Facility (AHF), 20-ns beam pulses (bunches) are extracted from the 50-GeV main proton synchrotron and then are transported to the target by an elaborated transport system. The beam transport system splits the beam bunches into equal parts in its splitting sections so that up to 12 synchronous beam pulses can be delivered to the target for the multi-axis proton radiography. Information about the transverse positions of the beams in the splitters, and possibly the bunch longitudinal profile, should be delivered by some diagnostic devices. Possible candidates are the circular wall current monitors in the circular pipes connecting the splitter elements, or the conventional stripline BPMs. In any case, we need some estimates on how well the transverse positions of the two beams can be resolved by these monitors.

  20. Report III on Switchyard beam position monitor

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Hengjie

    1994-09-01

    In this report, we will first discuss some basic beam position measurement schemes. Then, we will analyze the characteristics of several possible bpm designs to find out the optimum scheme for the switchyard application. Finally, the design of the second SY BPM prototype generated from our research will be introduced. As a by-product of developing the second prototype, a possible design of the bpm for handling fast spill with very short duty-cycle has also been found.

  1. APCAL1: Beam Position Monitor Program

    International Nuclear Information System (INIS)

    APCAL1 is an applications program operational on the PEP MODCOMP IV computer for the purpose of converting beam position monitor (BPM) button voltage readings to x,y coordinates. Calibration information and the BPM readings are read from the MODCOMP IV data base. Corresponding x,y coordinates are written in the data base for use by other programs. APCAL1 is normally activated by another program but can be activated by a touch panel for checkout purposes

  2. Signal Processing for Beam Position Monitors

    CERN Document Server

    Vismara, Giuseppe

    2000-01-01

    At the first sight the problem to determine the beam position from the ratio of the induced charges of the opposite electrodes of a beam monitor seems trivial, but up to now no unique solution has been found that fits the various demands of all particle accelerators. The purpose of this paper is to help "instrumentalists" to choose the best processing system for their particular application, depending on the machine size, the input dynamic range, the required resolution and the acquisition speed. After a general introduction and an analysis of the electrical signals to be treated (frequency and time domain), the definition of the electronic specifications will be reviewed. The tutorial will present the different families in which the processing systems can be grouped. A general description of the operating principles with relative advantages and disadvantages for the most employed processing systems is presented. Special emphasis will be put on recent technological developments based on telecommunication circ...

  3. Statistical Treatment of Beam Position Monitor Data

    CERN Document Server

    Reiter, Andreas; Chorniy, Oleksandr

    2016-01-01

    We review beam position monitors adopting the perspective of an analogue-to- digital converter in a sampling data acquisition system. From a statistical treatment of independent data samples we derive basic formulae of position uncertainty for beam position monitors. Uncertainty estimates only rely on a few simple model parameters and have been calculated for two "practical" signal shapes, a square pulse and a triangular pulse. The analysis has been carried out for three approaches: the established signal integration and root-sum-square ap- proaches, and a least-square fit for the models of direct proportion and straight-line. The latter approach has not been reported in the literature so far. The straight-line fit provides the most robust estimator since it does not require baseline restoration, it is immune to signal offsets, and its standard deviation is smallest. Consequently, of the analysed estimators it promises the highest fidelity of results. The fit approach represents a simple, natural way to analy...

  4. Position-And-Direction Sensor For Light Beams

    Science.gov (United States)

    Smith, Matthew A.

    1989-01-01

    Optoelectronic sensor measures both position and direction of incidence of laser beam or other narrow beam of light. New sensor part of robotic welding system in which laser beam reflected from pool of molten metal and monitored by lateral-position sensor. To provide unambiguous measurement of both lateral position and direction of incident beam, sensor includes two position-sensitive photodetectors or linear arrays of photodetectors.

  5. NSLS-II RF BEAM POSITION MONITOR

    Energy Technology Data Exchange (ETDEWEB)

    Vetter, K.; Della Penna, A. J.; DeLong, J.; Kosciuk, B.; Mead, J.; Pinayev, I.; Singh, O.; Tian, Y.; Ha, K.; Portmann, G.; Sebek J.

    2011-03-28

    An internal R&D program has been undertaken at BNL to develop a sub-micron RF Beam Position Monitor (BPM) for the NSLS-II 3rd generation light source that is currently under construction. The BPM R&D program started in August 2009. Successful beam tests were conducted 15 months from the start of the program. The NSLS-II RF BPM has been designed to meet all requirements for the NSLS-II Injection system and Storage Ring. Housing of the RF BPM's in +-0.1 C thermally controlled racks provide sub-micron stabilization without active correction. An active pilot-tone has been incorporated to aid long-term (8hr min) stabilization to 200nm RMS. The development of a sub-micron BPM for the NSLS-II has successfully demonstrated performance and stability. Pilot Tone calibration combiner and RF synthesizer has been implemented and algorithm development is underway. The program is currently on schedule to start production development of 60 Injection BPM's starting in the Fall of 2011. The production of {approx}250 Storage Ring BPM's will overlap the Injection schedule.

  6. ORNL positive ion neutral beam program

    International Nuclear Information System (INIS)

    The neutral beam group at Oak Ridge National Laboratory has constructed neutral beam generators for the ORMAK and PLT devices, is presently constructing neutral beam devices for the ISX and PDX devices, and is contemplating the construction of neutral beam systems for the advanced TNS device. These neutral beam devices stem from the pioneering work on ion sources of G. G. Kelley and O. B. Morgan. We describe the ion sources under development at this Laboratory, the beam optics exhibited by these sources, as well as some theoretical considerations, and finally the remainder of the beamline design

  7. The positioning device of beam probes for accelerator LUE-200

    International Nuclear Information System (INIS)

    The description of a device for the positioning of sliding beam probes which is the part of the beam diagnostic system for the LUE-200 electron linac of IREN installation is presented. The device provides remote control of input-output operation of beam probes of five diagnostic stations established in an accelerating tract and in the beam transportation channel of the accelerator

  8. Development of beam position monitor for test beam of BEPC II

    International Nuclear Information System (INIS)

    Three stripline beam position monitors and some feed-throughs were developed to measure the position of beam non-interceptively in test beam facility. After three stripline beam position monitors were produced, calibrations of the monitors were carried out on a workbench, which has high precision and is controlled by a computer. Then two monitor's were installed at the beam line and some experiments were carried out. Four 1 mm thickness stainless steel strips are main modules of the monitor, signals induced in these strips reflect the position of the beam bunch. Calibration coefficient, system characteristic impedance and port transmission coefficient of monitor are introduced in this paper. (authors)

  9. Hough Transform Based Corner Detection for Laser Beam Positioning

    International Nuclear Information System (INIS)

    In laser beam alignment in addition to detecting position, one must also determine the rotation of the beam. This is essential when a commissioning new laser beam for National Ignition Facility located at the Lawrence Livermore National Laboratory. When the beam is square, the positions of the corners with respect to one another provides an estimate of the rotation of the beam. This work demonstrates corner detection in the presence or absence of a second order non-uniform illumination caused by a spatial mask. The Hough transform coupled with illumination dependent pre-processing is used to determine the corner points. We show examples from simulated and real NIF images

  10. Hough Transform Based Corner Detection for Laser Beam Positioning

    Energy Technology Data Exchange (ETDEWEB)

    Awwal, A S

    2005-07-26

    In laser beam alignment in addition to detecting position, one must also determine the rotation of the beam. This is essential when a commissioning new laser beam for National Ignition Facility located at the Lawrence Livermore National Laboratory. When the beam is square, the positions of the corners with respect to one another provides an estimate of the rotation of the beam. This work demonstrates corner detection in the presence or absence of a second order non-uniform illumination caused by a spatial mask. The Hough transform coupled with illumination dependent pre-processing is used to determine the corner points. We show examples from simulated and real NIF images.

  11. Beam Position Monitor at the PLS BTL

    CERN Document Server

    Kim, Sung-Chul; Han, Yeung-Jin; Tae Kim, Do; Woo Lee, Wol; Yun Huang Jung

    2005-01-01

    Electron Linac at the Pohnag Accelerator Laboratory (PAL) has been operated continuously as the full energy injector for storage ring. Linac and storage ring energy has been 2.0 GeV since Dec. 1994, and 2.5 GeV since Oct. 2002. In Aug. 2004, thirteen BPMs are newly installed at BTL(Beam Transport Line) for beam trajectory measurement and feedback. These BPMs consist of 100mm strip-line electrodes in 150mm long chamber, and 500MHz log-ratio signal processing circuits. BPM data acquisition system is developed as EPICS IOC using NI S-series data acquisition board and NI LabView 7.1. BTL BPMs will be used for optic correction and beam energy feedback for PLS beam injection. This paper describes on design, test results, installation and data acquisition system of the PLS BTL BPM.

  12. Monitoring the beam position in the SLC interaction region

    International Nuclear Information System (INIS)

    The Stanford Linear Collider requires special Beam Position Monitors near the Interaction Point (IP) to bring the two beams (e+ and e-) into collision. These beams pass through two monitors on each side of the IP with a short time separation (about 20 and 50 ns). The mechanics of the monitors as well as the electronics will be described. In order to bring beams of several microns diameter into collision at the IP, these monitors measure beam deflection induced by the presence of the opposite beam

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

    International Nuclear Information System (INIS)

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

  14. A phase-space beam position monitor for synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Samadi, Nazanin, E-mail: nazanin.samadi@usask.ca [University of Saskatchewan, 107 Wiggins Road, Saskatoon, SK (Canada); Bassey, Bassey; Martinson, Mercedes [University of Saskatchewan, 116 Science Place, Saskatoon, SK (Canada); Belev, George; Dallin, Les; Jong, Mark de [Canadian Light Source, 44 Innovation Boulevard, Saskatoon, SK (Canada); Chapman, Dean [University of Saskatchewan, 107 Wiggins Road, Saskatoon, SK (Canada)

    2015-06-25

    A system has been developed to measure the vertical position and angle of the electron beam at a single location from a synchrotron source. The system uses a monochromator tuned to the absorption edge of a contrast material and has a sensitivity comparable with other beam position monitors. The stability of the photon beam position on synchrotron beamlines is critical for most if not all synchrotron radiation experiments. The position of the beam at the experiment or optical element location is set by the position and angle of the electron beam source as it traverses the magnetic field of the bend-magnet or insertion device. Thus an ideal photon beam monitor would be able to simultaneously measure the photon beam’s position and angle, and thus infer the electron beam’s position in phase space. X-ray diffraction is commonly used to prepare monochromatic beams on X-ray beamlines usually in the form of a double-crystal monochromator. Diffraction couples the photon wavelength or energy to the incident angle on the lattice planes within the crystal. The beam from such a monochromator will contain a spread of energies due to the vertical divergence of the photon beam from the source. This range of energies can easily cover the absorption edge of a filter element such as iodine at 33.17 keV. A vertical profile measurement of the photon beam footprint with and without the filter can be used to determine the vertical centroid position and angle of the photon beam. In the measurements described here an imaging detector is used to measure these vertical profiles with an iodine filter that horizontally covers part of the monochromatic beam. The goal was to investigate the use of a combined monochromator, filter and detector as a phase-space beam position monitor. The system was tested for sensitivity to position and angle under a number of synchrotron operating conditions, such as normal operations and special operating modes where the photon beam is intentionally altered

  15. Beam line error analysis, position correction, and graphic processing

    International Nuclear Information System (INIS)

    A beam transport line error analysis and beam position correction code called ''EAC'' has been developed in association with a graphics and data post-processing package for TRANSPORT. Based on the linear optics design using TRANSPORT or other general optics codes, EAC independently analyzes effects of magnet misalignments, and systematic and statistical errors of magnetic fields, as well as the effects of the initial beam positions on the central trajectory and on the transverse beam emittance dilution. EAC also provides an efficient way to develop beam line trajectory correcting schemes. The post-processing package generates various types of graphics including beam line geometrical layout, plots of the Twiss parameters, and beam envelopes. It also generates an EAC input file, thus connecting EAC with general optics codes. EAC and the post-processing package are small codes that are easy to access and use. They have become useful tools for the design of transport lines at the Superconducting Super Collider Laboratory

  16. Beam Position Monitor Electronics Upgrade for Fermilab Switchyard

    CERN Document Server

    Stabile, P; Fitzgerald, J A; Liu, N; Morris, D K; Prieto, P S; Seraphin, J P

    2015-01-01

    The beam position monitor (BPM) system for Fermilab Switchyard (SY) provides the position, intensity and integrated intensity of the 53.10348 MHz RF bunched resonant extracted beam from the Main Injector over 4 seconds of spill. The total beam intensity varies from 1x10^11 to 1x10^13 protons. The spill is measured by stripline beam postion monitors and resonant circuit. The BPMs have an external resonant circuit tuned to 53.10348 MHz. The corresponding voltage signal out of the BPM has been estimated to be between -110 dBm and -80 dBm.

  17. Beam Position and Phase Monitor - Wire Mapping System

    Energy Technology Data Exchange (ETDEWEB)

    Watkins, Heath A [Los Alamos National Laboratory; Shurter, Robert B. [Los Alamos National Laboratory; Gilpatrick, John D. [Los Alamos National Laboratory; Kutac, Vincent G. [Los Alamos National Laboratory; Martinez, Derwin [Los Alamos National Laboratory

    2012-04-10

    The Los Alamos Neutron Science Center (LANSCE) deploys many cylindrical beam position and phase monitors (BPPM) throughout the linac to measure the beam central position, phase and bunched-beam current. Each monitor is calibrated and qualified prior to installation to insure it meets LANSCE requirements. The BPPM wire mapping system is used to map the BPPM electrode offset, sensitivity and higher order coefficients. This system uses a three-axis motion table to position the wire antenna structure within the cavity, simulating the beam excitation of a BPPM at a fundamental frequency of 201.25 MHz. RF signal strength is measured and recorded for the four electrodes as the antenna position is updated. An effort is underway to extend the systems service to the LANSCE facility by replacing obsolete electronic hardware and taking advantage of software enhancements. This paper describes the upgraded wire positioning system's new hardware and software capabilities including its revised antenna structure, motion control interface, RF measurement equipment and Labview software upgrades. The main purpose of the wire mapping system at LANSCE is to characterize the amplitude response versus beam central position of BPPMs before they are installed in the beam line. The wire mapping system is able to simulate a beam using a thin wire and measure the signal response as the wire position is varied within the BPPM aperture.

  18. Determination of beam intensity and position in a particle accelerator

    CERN Document Server

    Kasprowicz, G

    2011-01-01

    A subject of the thesis is conception, design, implementation, tests and deployment of new position measurement system of particle bunch in the CERN PS circular accelerator. The system is based on novel algorithms of particle position determination. The Proton Synchrotron accelerator (PS), installed at CERN, although commissioned in 1959, still plays a central role in the production of beams for the Antiproton Decelerator, Super Proton Synchrotron, various experimental areas and for the Large Hadron Collider (LHC). The PS produces beams of different types of particles, mainly protons, but also various species of ions. Almost all these particle beams pass through the PS. The quality of the beams delivered to the LHC has a direct impact on the effective luminosity, and therefore the performance of the instrumentation of the PS is of great importance. The old trajectory and orbit measurement system of the PS is dated back to 1988 and no longer fulfilled present day requirements. It used 40 beam position monitors...

  19. Simulations of LEIR Injection Line Beam Position Monitors

    CERN Document Server

    Maltseva, Mariya

    2016-01-01

    In this paper sensitivity characteristics of a beam position monitor are described. Characteristics are obtained during the simulations in CST Studio, the results are compared with the calculated values. The results for a low-beta beam and with a wire are compared.

  20. Video-based beam position monitoring at CHESS

    Science.gov (United States)

    Revesz, Peter; Pauling, Alan; Krawczyk, Thomas; Kelly, Kevin J.

    2012-10-01

    CHESS has pioneered the development of X-ray Video Beam Position Monitors (VBPMs). Unlike traditional photoelectron beam position monitors that rely on photoelectrons generated by the fringe edges of the X-ray beam, with VBPMs we collect information from the whole cross-section of the X-ray beam. VBPMs can also give real-time shape/size information. We have developed three types of VBPMs: (1) VBPMs based on helium luminescence from the intense white X-ray beam. In this case the CCD camera is viewing the luminescence from the side. (2) VBPMs based on luminescence of a thin (~50 micron) CVD diamond sheet as the white beam passes through it. The CCD camera is placed outside the beam line vacuum and views the diamond fluorescence through a viewport. (3) Scatter-based VBPMs. In this case the white X-ray beam passes through a thin graphite filter or Be window. The scattered X-rays create an image of the beam's footprint on an X-ray sensitive fluorescent screen using a slit placed outside the beam line vacuum. For all VBPMs we use relatively inexpensive 1.3 Mega-pixel CCD cameras connected via USB to a Windows host for image acquisition and analysis. The VBPM host computers are networked and provide live images of the beam and streams of data about the beam position, profile and intensity to CHESS's signal logging system and to the CHESS operator. The operational use of VBPMs showed great advantage over the traditional BPMs by providing direct visual input for the CHESS operator. The VBPM precision in most cases is on the order of ~0.1 micron. On the down side, the data acquisition frequency (50-1000ms) is inferior to the photoelectron based BPMs. In the future with the use of more expensive fast cameras we will be able create VBPMs working in the few hundreds Hz scale.

  1. Calibration of INDUS-1 and booster beam position indicators

    International Nuclear Information System (INIS)

    The 0.45 GeV Indus-1 synchrotron radiation facility at Centre for Advanced Technology (C.A.T) Indore, has 6 beam position indicators in Booster and 4 beam position indicators in Indus-1 ring. The beam position indicators (BPI) play an important role in commissioning and operation of accelerators. The accurate determination of the offsets relative to magnetic axis and sensitivities of individual BPIs is thus needed. The bench calibration of Indus-1 and Booster beam position indicators was carried out. A fully automatic computer based calibration system has been developed for calibration of Indus-1 and Indus-2 BPIs. The calibration results of Indus-1 and Booster BPIs and calibration system used for calibration is presented in this paper. (author)

  2. Solution and Positive Solution to Nonlinear Cantilever Beam Equations

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Using the decomposition technique of equation and the fixed point theorem, the existence of solution and positive solution is studied for a nonlinear cantilever beam equation. The equation describes the deformation of the elastic beam with a fixed end and a free end. The main results show that the equation has at least one solution or positive solution, provided that the "height" of nonlinear term is appropriate on a bounded set.

  3. Determination of Beam Intensity and Position in a Particle Accelerator

    CERN Document Server

    Kasprowicz, Grzegorz; Raich, Uli

    2011-10-04

    A subject of the thesis is conception, design, implementation, tests and deployment of new position measurement system of particle bunch in the CERN PS circular accelerator. The system is based on novel algorithms of particle position determination. The Proton Synchrotron accelerator (PS), installed at CERN†, although commissioned in 1959, still plays a central role in the production of beams for the Antiproton Decelerator, Super Proton Synchrotron, various experimental areas and for the Large Hadron Collider (LHC)‡. The PS produces beams of different types of particles, mainly protons, but also various species of ions. Almost all these particle beams pass through the PS. The quality of the beams delivered to the LHC has a direct impact on the effective luminosity, and therefore the performance of the instrumentation of the PS is of great importance. The old trajectory and orbit measurement system of the PS is dated back to 1988 and no longer fulfilled present day requirements. It used 40 beam posi...

  4. Beam position and phase measurements of microampere beams at the Michigan State University REA3 facility

    CERN Document Server

    Crisp, J; Durickovic, B; Kiupel, G; Krause, S; Leitner, D; Nash, S; Rodriguez, J A; Russo, T; Webber, R; Wittmer, W; Eddy, N; Briegel, C; Fellenz, B; Slimmer, D; Wendt, M

    2013-01-01

    A high power CW, heavy ion linac will be the driver accelerator for the Facility for Rare Isotope Beams (FRIB) being designed at Michigan State University (MSU). The linac requires a Beam Position Monitoring (BPM) system with better than 100 micron resolution at 100 microamperes beam current. A low beam current test of the candidate technology, button pick-ups and direct digital down-conversion signal processing, was conducted in the ReA3 re-accelerated beam facility at Michigan State University. The test is described. Beam position and phase measurement results, demonstrating ~250 micron and ~1.5 degree resolution in a 45 kHz bandwidth for a 1.0 microampere beam current, are reported.

  5. Nonlinearities and effects of transverse beam size in beam position monitors

    Science.gov (United States)

    Kurennoy, Sergey S.

    2001-09-01

    The fields produced by a long beam with a given transverse charge distribution in a homogeneous vacuum chamber are studied. Signals induced by a displaced finite-size beam on electrodes of a beam position monitor (BPM) are calculated and compared to those produced by a pencil beam. The nonlinearities and corrections to BPM signals due to a finite transverse beam size are calculated for an arbitrary chamber cross section. Simple analytical expressions are given for a few particular transverse distributions of the beam current in a circular or rectangular chamber. Of particular interest is a general proof that in an arbitrary homogeneous chamber the beam-size corrections vanish for any axisymmetric beam current distribution.

  6. Development of digital beam position monitor based on software radio

    International Nuclear Information System (INIS)

    Digital beam position monitor processor is the key part of a beam position system. A BPM processor based on software radio is much better than traditional processors in terms of the resolution and flexibility. In this paper, we report technical specifications and design considerations of the digital beam position monitor developed at Shanghai Synchrotron Radiation Facility (SSRF). The turn-by-turn electronic resolution of the processor is better than 1.5 μm, when the input power is larger than -30 dBm, and the resolution is better than 2 μm in a test in the SSRF storage ring, with the beam current of over 150 mA. (authors)

  7. Performance of a High Resolution Cavity Beam Position Monitor System

    Energy Technology Data Exchange (ETDEWEB)

    Walston, S; Boogert, S; Chung, C; Fitsos, P; Frisch, J; Gronberg, J; Hayano, H; Honda, Y; Kolomensky, Y; Lyapin, A; Malton, S; May, J; McCormick, D; Meller, R; Miller, D; Orimoto, T; Ross, M; Slater, M; Smith, S; Smith, T; Terunuma, N; Thomson, M; Urakawa, J; Vogel, V; Ward, D; White, G

    2006-12-18

    It has been estimated that an RF cavity Beam Position Monitor (BPM) could provide a position measurement resolution of less than one nanometer. We have developed a high resolution cavity BPM and associated electronics. A triplet comprised of these BPMs was installed in the extraction line of the Accelerator Test Facility (ATF) at the High Energy Accelerator Research Organization (KEK) for testing with its ultra-low emittance beam. The three BPMs were each rigidly mounted inside an alignment frame on six variable-length struts which could be used to move the BPMs in position and angle. We have developed novel methods for extracting the position and tilt information from the BPM signals including a robust calibration algorithm which is immune to beam jitter. To date, we have demonstrated a position resolution of 15.6 nm and a tilt resolution of 2.1 {micro}rad over a dynamic range of approximately {+-} 20 {micro}m.

  8. Performance of a High Resolution Cavity Beam Position Monitor System

    Energy Technology Data Exchange (ETDEWEB)

    Walston, Sean; Boogert, Stewart; Chung, Carl; Fitsos, Joe; Frisch, Joe; Gronberg, Jeff; Hayano, Hitoshi; Honda, Yosuke; Kolomensky, Yury; Lyapin, Alexey; Malton, Stephen; May, Justin; McCormick, Douglas; Meller, Robert; Miller, David John; Orimoto, Toyoko; Ross, Marc; Slater, Mark; Smith, Steve; Smith, Tonee; Terunuma, Nobuhiro; /Fermilab /UC,

    2007-06-08

    It has been estimated that an RF cavity Beam Position Monitor (BPM) could provide a position measurement resolution of less than one nanometer. We have developed a high resolution cavity BPM and associated electronics. A triplet comprised of these BPMs was installed in the extraction line of the Accelerator Test Facility (ATF) at the High Energy Accelerator Research Organization (KEK) for testing with its ultra-low emittance beam. The three BPMs were each rigidly mounted inside an alignment frame on six variable-length struts which could be used to move the BPMs in position and angle. We have developed novel methods for extracting the position and tilt information from the BPM signals including a robust calibration algorithm which is immune to beam jitter. To date, we have demonstrated a position resolution of 15.6 nm and a tilt resolution of 2.1 {mu}rad over a dynamic range of approximately {+-} 20 {mu}m.

  9. EXPERIMENTAL RESULTS FROM A MICROWAVE CAVITY BEAM POSITION MONITOR.

    Energy Technology Data Exchange (ETDEWEB)

    BALAKIN,V.; BAZHAN,A.; LUNEV,P.; SOLYAK,N.; VOGEL,V.; ZHOGOLEV,P.; LISITSYN,A.; YAKIMENKO,V.

    1999-03-29

    Future Linear Colliders have hard requirements for the beam transverse position stability in the accelerator. A beam Position Monitor (BPM) with the resolution better than 0.1 micron in the single bunch regime is needed to control the stability of the beam position along the linac. Proposed BPM is based on the measurement of the asymmetrical mode excited by single bunch in the cavity. Four stages of signal processing (space-, time-, frequency- and phase-filtering providing the required signal-to-noise ratio) are used to obtain extremely high resolution. The measurement set-up was designed by BINP and installed at ATF/BNL to test experimentally this concept. The set-up includes three two-coordinates BPM's at the frequency of 13.566 GHz, and reference intensity/phase cavity. BPM's were mounted on support table. The two-coordinates movers allow to move and align BPM's along the straight line, using the signals from the beam. The position of each monitor is controlled by the sensors with the accuracy 0.03 micron. The information from three monitors allows to exclude angle and position jitter of the beam and measure BPM resolution. In the experiments the resolution of about 0.15 micron for 0.25 nC beam intensity was obtained, that is close to the value required.

  10. Bench calibration of INDUS-2 beam position indicators

    International Nuclear Information System (INIS)

    A third generation synchrotron radiation source of energy 2.5 GeV named INDUS-2 at Centre for Advanced Technology (C.A.T), Indore (M.P) is in the advanced stage of construction. Accurate determination and correction of beam closed orbit in INDUS-2 machine within 100 of microns is a very desirable goal. Bench based calibration of Beam Position Indicators (BPI) play a very important and useful role during initial commissioning of electron machines. To precisely measure transverse position of electron beam in the Indus-2 storage ring, 56 Beam Position Indicators (BPI) will be installed in INDUS-2 machine. Out of 56 Beam Position Indicators 40 are of individual type whereas 16 are integrated with dipole vacuum chamber. The Beam Position Indicators are required to be calibrated before they can be installed. The calibration is done to determine electrical offset with respect to defined mechanical centre, to determine displacement sensitivities as well as non linearity's of BPI. Ideally when beam passes through the geometrical center of BPI's, all electrodes should have same signal strength. However due to different capacitance of electrodes and offset and drift in electronics, the electrical centre (mechanical x, y where all electrodes shows same signal strength) differs from mechanical centre of BPI. A fully automatic calibration system has been developed to carry out the calibration of Beam Position Indicators. A calibration software has been developed which has necessary utilities to process and display calibration data and results. This paper describes the calibration results of Indus-2 BPM. (author)

  11. Beam Position-Phase Monitors for SNS Linac

    Science.gov (United States)

    Kurennoy, Sergey

    Electromagnetic modeling with MAFIA of the combined beam position-phase monitors (BPPMs) for the Spallation Neutron Source (SNS) linac has been performed. Time-domain 3-D simulations are used to compute the signal amplitudes and phases on the BPPM electrodes for a given processing frequency, 402.5 MHz or 805 MHz, as functions of the beam transverse position. Working with a summed signal from all the BPPM electrodes provides a good way to measure accurately the beam phase. While for an off-axis beam the signal phases on the individual electrodes can differ from those for a centered beam by a few degrees, the phase of the summed signal is found to be independent of the beam transverse position inside the device. Based on the analysis results, an optimal BPPM design with 4 one-end-shorted 60-degree electrodes has been chosen. It provides a good linearity and sufficient signal power for both position and phase measurements, while satisfying the linac geometrical constrains and mechanical requirements.

  12. Beam Position-Phase Monitors for SNS Linac

    CERN Document Server

    Kurennoy, S S

    2000-01-01

    Electromagnetic modeling with MAFIA of the combined beam position-phase monitors (BPPMs) for the Spallation Neutron Source (SNS) linac has been performed. Time-domain 3-D simulations are used to compute the signal amplitudes and phases on the BPPM electrodes for a given processing frequency, 402.5 MHz or 805 MHz, as functions of the beam transverse position. Working with a summed signal from all the BPPM electrodes provides a good way to measure accurately the beam phase. While for an off-axis beam the signal phases on the individual electrodes can differ from those for a centered beam by a few degrees, the phase of the summed signal is found to be independent of the beam transverse position inside the device. Based on the analysis results, an optimal BPPM design with 4 one-end-shorted 60-degree electrodes has been chosen. It provides a good linearity and sufficient signal power for both position and phase measurements, while satisfying the linac geometrical constrains and mechanical requirements.

  13. Study of CMOS image sensors for laser beam position detection

    International Nuclear Information System (INIS)

    We report on the study made on commercial CMOS image sensors in order to determine their feasibility for light beam position reconstruction. Measurements of the intrinsic position resolution, sensor photoresponse and uniformity were done. The effect of eventual background illumination was evaluated. The precision on the spatial point reconstruction was determined from linearity measurements. First results on gamma-ray radiation tolerance are presented

  14. Progress on the development of APS beam position monitoring system

    International Nuclear Information System (INIS)

    This paper describes the development status of the beam position monitoring system for the Advanced Photon Source (APS), a third-generation light source now under construction at Argonne National Laboratory. The accelerator complex will consist of an electron linac, a positron linac, a positron accumulator ring (PAR), an injector synchrotron and a storage ring. For beam position measurement, striplines will be used on the linacs, while button-type pickups will be used on the injector synchrotron and the storage ring. A test stand with a prototype injector synchrotron beam position monitor (BPM) unit has been built, and we present the results of position calibration measurements using a wire. Comparison of the results with theoretical calculations will be presented. The current effort on similar storage ring BPM system measurements will also be discussed. 4 refs., 5 figs., 2 tabs

  15. Prototyping of beam position monitor for medium energy beam transport section of RAON heavy ion accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Hyojae, E-mail: lkcom@ibs.re.kr; Jin, Hyunchang; Jang, Ji-Ho; Hong, In-Seok [Rare Isotope Science Project, Institute for Basic Science, Daejeon (Korea, Republic of)

    2016-02-15

    A heavy ion accelerator, RAON is going to be built by Rare Isotope Science Project in Korea. Its target is to accelerate various stable ions such as uranium, proton, and xenon from electron cyclotron resonance ion source and some rare isotopes from isotope separation on-line. The beam shaping, charge selection, and modulation should be applied to the ions from these ion sources because RAON adopts a superconducting linear accelerator structure for beam acceleration. For such treatment, low energy beam transport, radio frequency quadrupole, and medium energy beam transport (MEBT) will be installed in injector part of RAON accelerator. Recently, development of a prototype of stripline beam position monitor (BPM) to measure the position of ion beams in MEBT section is under way. In this presentation, design of stripline, electromagnetic (EM) simulation results, and RF measurement test results obtained from the prototyped BPM will be described.

  16. Prototyping of beam position monitor for medium energy beam transport section of RAON heavy ion accelerator

    Science.gov (United States)

    Jang, Hyojae; Jin, Hyunchang; Jang, Ji-Ho; Hong, In-Seok

    2016-02-01

    A heavy ion accelerator, RAON is going to be built by Rare Isotope Science Project in Korea. Its target is to accelerate various stable ions such as uranium, proton, and xenon from electron cyclotron resonance ion source and some rare isotopes from isotope separation on-line. The beam shaping, charge selection, and modulation should be applied to the ions from these ion sources because RAON adopts a superconducting linear accelerator structure for beam acceleration. For such treatment, low energy beam transport, radio frequency quadrupole, and medium energy beam transport (MEBT) will be installed in injector part of RAON accelerator. Recently, development of a prototype of stripline beam position monitor (BPM) to measure the position of ion beams in MEBT section is under way. In this presentation, design of stripline, electromagnetic (EM) simulation results, and RF measurement test results obtained from the prototyped BPM will be described.

  17. Beam positioning stability analysis on large laser facilities

    Institute of Scientific and Technical Information of China (English)

    Fang; Liu; Zhigang; Liu; Liunian; Zheng; Hongbiao; Huang; Jianqiang; Zhu

    2013-01-01

    Beam positioning stability in a laser-driven inertial confinement fusion(ICF) facility is a vital problem that needs to be fixed. Each laser beam in the facility is transmitted in lots of optics for hundreds of meters, and then targeted in a micro-sized pellet to realize controllable fusion. Any turbulence in the environment in such long-distance propagation would affect the displacement of optics and further result in beam focusing and positioning errors. This study concluded that the errors on each of the optics contributed to the target, and it presents an efficient method of enhancing the beam stability by eliminating errors on error-sensitive optics. Optimizations of the optical system and mechanical supporting structures are also presented.

  18. Position Sensitive Detector Used to Detect Beam Profile

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Non-destructive diagnostic methods are very important for beam adjustments and monitors,especially when the beam intensity is less than 10~8 pps during the heavy-ion treatment of cancer.Now the diagnostic devices of HIFRL can’t satisfy the requests,so we decide to construct a detecting system of the residual-gas beam profile~([1,2]).The system uses the Position Sensitive Detector(PSD)~([3,4])based on microchannel plate(MCP)to

  19. A new digital beam position monitor in SSRF

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The newly developed Digital Beam Position Monitor (DBPM) system is introduced. The DBPM system differs with the conventional beam position monitor system in the use of DSP chips and the digital signal processing technology. It can be programmed on-line to select operation modes through EPICS control panel, and to measure various parameters of the third generation synchrotron radiation facility. This DBPM system can be used in the pre-injector LINAC, the transfer lines, the booster synchrotron and the storage ring. The electronic parameters of the DBPM system itself have been measured also.

  20. PAL-XFEL cavity beam position monitor pick-up design and beam test

    Science.gov (United States)

    Lee, Sojeong; Park, Young Jung; Kim, Changbum; Kim, Seung Hwan; Shin, Dong Cheol; Han, Jang-Hui; Ko, In Soo

    2016-08-01

    As an X-ray Free Electron Laser, PAL-XFEL is about to start beam commissioning. X-band cavity beam position monitor (BPM) is used in the PAL-XFEL undulator beam line. Prototypes of cavity BPM pick-up were designed and fabricated to test the RF characteristics. Also, the beam test of a cavity BPM pick-up was done in the Injector Test Facility (ITF). In the beam test, the raw signal properties of the cavity BPM pick-up were measured at a 200 pC bunch charge. According to the RF test and beam test results, the prototype cavity BPM pick-up design was confirmed to meet the requirements of the PAL-XFEL cavity BPM system.

  1. LHC Beam Instrumentation: Beam Position and Intensity Measurements (1/3)

    CERN Document Server

    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.

  2. Improvement of thermo-mechanical position stability of the beam position monitor in PLS-II

    CERN Document Server

    Ha, Taekyun; Kwon, Hyuckchae; Han, Hongsik; Park, Chongdo

    2016-01-01

    In the storage ring of PLS-II, we reduced mechanical displacement of electron beam position monitors (e-BPMs) that is caused by heating during e-beam storage. The orbit feedback system intends that the electron beam pass through the center of the BPM, so to provide stable photon beam into beamlines the BPM pickup itself must be stable to sub-micrometer precision. Thermal deformation of the vacuum chambers on which the BPM pickups are mounted is inevitable when the electron beam current is changed by unintended beam abort. We reduced this deformation by improving the vacuum chamber support and by enhancing the water cooling. We report the thermo-mechanical analysis and displacement measurements of BPM pickups after the improvements.

  3. BEAM POSITION AND PHASE MONITORS FOR THE LANSCE LINAC

    Energy Technology Data Exchange (ETDEWEB)

    McCrady, Rodney C. [Los Alamos National Laboratory; Gilpatrick, John D. [Los Alamos National Laboratory; Watkins, Heath A. [Los Alamos National Laboratory

    2012-04-11

    New beam-position and phase monitors are under development for the linac at the Los Alamos Neutron Science Center (LANSCE.) Transducers have been designed and are being installed. We are considering many options for the electronic instrumentation to process the signals and provide position and phase data with the necessary precision and flexibility to serve the various required functions. We'll present the various options under consideration for instrumentation along with the advantages and shortcomings of these options.

  4. Status of the Stripline Beam Position Monitor developement for the CLIC Drive Beam

    CERN Document Server

    Benot-Morell, A; Wendt, M; Faus-Golfe, A; Nappa, J M; Vilalte, S; Smith, S

    2013-01-01

    In collaboration with SLAC, LAPP and IFIC, a first prototype of a stripline Beam Position Monitor (BPM) for the CLIC Drive Beam and its associated readout electronics has been successfully tested in the CLIC Test Facility linac (CTF3) at CERN. In addition, a modified prototype with downstream terminated striplines is under development to improve the suppression of unwanted RF signal interference. This paper presents the results of the beam tests, and the most relevant aspects for the modified stripline BPM design and its expected improvements.

  5. Parasitic mode losses versus signal sensitivity in beam position monitors

    Science.gov (United States)

    Denard, J. C.; Bane, K. L.; Bijleveld, J.; Hutton, A. M.; Pellegrin, J. I.; Rivkin, L.; Wang, P.; Weaver, J. N.

    1985-04-01

    A beam position monitor (BPM) for a storage or damping ring may be subject to heating problems due to the parasitic mode (PM) losses, beam interception and synchrotron radiation interception. In addition, high PM losses can cause beam instabilities under some conditions. Recessing and/or masking the BPM may increase the PM losses in the process of solving the latter two problems. Three complementary methods for estimating the PM losses and for improving the design of a stripline directional coupler type of BPM: bench measurements, computer modeling (TBCI), and an equivalent circuit representation are presented. These methods lead to a decrease in PM losses without significant reduction in output signal for the north Stanford Linear Collider (SLC) damping ring BPMs.

  6. Beam Tests of a Prototype Stripline Beam Position Monitoring System for the Drive Beam of the CLIC Two-beam Module at CTF3

    CERN Document Server

    Benot-Morell, Alfonso; Nappa, Jean-Marc; Vilalte, Sebastien; Wendt, Manfred

    2016-01-01

    In collaboration with LAPP and IFIC, two units of a prototype stripline Beam Position Monitor (BPM) for the CLIC Drive Beam (DB), and its associated readout electronics have been successfully installed and tested in the Two-Beam-Module (TBM) at the CLIC Test Facility 3 (CTF3) at CERN. This paper gives a short overview of the BPM system and presents the performance measured under different Drive Beam configurations.

  7. Determination of Beam Intensity and Position in a Particle Accelerator

    CERN Document Server

    Kasprowicz, Grzegorz

    2010-01-01

    The Proton Synchrotron accelerator (PS), installed at CERN, although commissioned in 1959, still plays a central role in the production of beams for the Antiproton Decelerator, Super Proton Synchrotron, various experimental areas and for the Large Hadron Collider (LHC). The PS produces beams of different types of particles, mainly protons, but also various species of ions. Almost all these particle beams pass through the PS. The quality of the beams delivered to the LHC has a direct impact on the effective luminosity, and therefore the performance of the instrumentation of the PS is of great importance. The old trajec- tory and orbit measurement system of the PS dated back to 1988 and no longer fulfilled present day requirements. It used 40 beam position monitors (BPMs) and an analogue signal processing chain to acquire the trajectory of one single particle bunch out of many, over two consecutive turns at a maximum rate of once every 5ms. The BPMs were in good condition, however the electronics was aging and ...

  8. Beam Loss Position Monitor Using Cerenkov Radiation in Optical Fibers

    CERN Document Server

    Körfer, M

    2005-01-01

    Single pass Free Electron Lasers SASE-FELs are developed for high brightness and short wavelength applications. The VUV-FEL at DESY will reach an average beam power of about 72 kW. To avoid particle losses in the radiation sensitive undulators a collimator system is installed. However, the proper operation of the collimator system needs to be measured with a beam loss monitor. Conventional radiation sensor systems are not suited for the VUV-FEL undulators, because the free space in the undulator gap is less than 1 mm. A Beam Loss Position Monitor (BLPM) based on Cerenkov light in optical fibers allows the monitoring of losses inside the undulator. Electrons with energies above 175 keV generate Cerenkov light during their penetration of the optical fiber. The fast response of the Cerenkov signal is detected with photomultipliers at the end of the irradiated fibers. The beam loss position along the section of interest can be determinate by exploiting the system trigger (bunch clock) of the accelerator system. T...

  9. Beam position monitors for the high brightness lattice

    International Nuclear Information System (INIS)

    Engineering developments associated with the high brightness lattice and the projected change in machine operating parameters will inherently affect the diagnostics systems and devices installed at present in the storage ring. This is particularly true of the beam position monitoring (BPI) system. The new sixteen unit cell lattice with its higher betatron tune values and the limited space available in the redesigned machine straights for fitting standard BPI vessels forces a fundamental re-evaluation of the beam position monitor system. The design aims for the new system are based on accepting the space limitations imposed while still providing the monitor points required to give good radial and vertical closed orbit plots. The locations of BPI's in the redesigned machine straights is illustrated. A description of the new BPI assemblies and their calibration is given. The BPI's use capacitance button type pick-ups; their response is described. (U.K.)

  10. Beam Position Monitoring in the CSU Accelerator Facility

    Science.gov (United States)

    Einstein, Joshua; Vankeuren, Max; Watras, Stephen

    2014-03-01

    A Beam Position Monitoring (BPM) system is an integral part of an accelerator beamline, and modern accelerators can take advantage of newer technologies and designs when creating a BPM system. The Colorado State University (CSU) Accelerator Facility will include four stripline detectors mounted around the beamline, a low-noise analog front-end, and digitization and interface circuitry. The design will support a sampling rate greater than 10 Hz and sub-100 μm accuracy.

  11. Single Pass Stripline Beam Position Monitor Design, Fabrication and Commissioning

    Directory of Open Access Journals (Sweden)

    McKinlay J.

    2012-10-01

    Full Text Available To monitor the position of the electron beam during transport from the Booster Synchrotron to the Storage Ring at the Australian Synchrotron, a stripline Beam Position Monitor (BPM has been designed, fabricated and installed in-house. The design was based on an existing stripline in the Booster and modified for the transfer line with a particular emphasis on ensuring the line impedance is properly matched to the detector system. The initial bench tests of a prototype stripline showed that the fabrication of the four individual striplines in the BPM was made precisely, each with a measured standing wave ratio (SWR of 1.8 at 500 MHz. Further optimization for impedance matching will be done for new stripline BPMs. The linearity and gain factor was measured with the detector system. The detector system that digitizes the signals is an Instrumentation Technologies Brilliance Single Pass [1]. The results show an error of 1 mm at an offset (from the electrical centre of 10 mm when a linear gain factor is assumed and an RMS noise of ~150 um that decreases to < 10 um with increasing signal intensity. The results were under our requirements for the transport line. The commissioning results of the stripline will also be presented showing a strong signal for an electron beam with an estimated integrated charge of ~50 nC with a position stability of 28 um (horizontal and 75 um (vertical.

  12. First Experiences of Beam Presence Detection Based on Dedicated Beam Position Monitors

    CERN Document Server

    Jalal, A; Gasior, M; Todd, B

    2011-01-01

    High intensity particle beam injection into the LHC is only permitted when a low intensity pilot beam is already circulating in the LHC. This requirement addresses some of the risks associated with high intensity injection, and is enforced by a so-called Beam Presence Flag (BPF) system which is part of the interlock chain between the LHC and its injector complex. For the 2010 LHC run, the detection of the presence of this pilot beam was implemented using the LHC Fast Beam Current Transformer (FBCT) system. However, the primary function of the FBCTs, that is reliable measurement of beam currents, did not allow the BPF system to satisfy all quality requirements of the LHC Machine Protection System (MPS). Safety requirements associated with high intensity injections triggered the development of a dedicated system, based on Beam Position Monitors (BPM). This system was meant to work first in parallel with the FBCT BPF system and eventually replace it. At the end of 2010 and in 2011, this new BP...

  13. Performance of a reentrant cavity beam position monitor

    Energy Technology Data Exchange (ETDEWEB)

    Simon, C.; Luong, M.; Chel, S.; Napoly, O.; Novo, J.; Roudier, D. [CEA Saclay, DSM, Irfu, SACM, F-91191 Gif Sur Yvette, (France); Rouviere, N. [CNRS, IN2P3-IPN, F-91406 Orsay, (France); Baboi, N.; Mildner, N.; Nolle, D. [DESY, D-22603 Hamburg, (Germany)

    2008-07-01

    The beam-based alignment and feedback systems, essential operations for the future colliders, require high resolution beam position monitors (BPMs). In the framework of the European CARE/SRF program, a reentrant cavity BPM with its associated electronics was developed by the CEA/DSM/Irfu in collaboration with DESY. The design, the fabrication, and the beam test of this monitor are detailed within this paper. This BPM is designed to be inserted in a cryo-module, work at cryogenic temperature in a clean environment. It has achieved a resolution better than 10 {mu}m and has the possibility to perform bunch to bunch measurements for the X-ray free electron laser (X-FEL) and the International Linear Collider (ILC). Its other features are a small size of the rf cavity, a large aperture (78 mm), and an excellent linearity. A first prototype of a reentrant cavity BPM was installed in the free electron laser in Hamburg (FLASH), at Deutsches Elektronen-Synchrotron (DESY) and demonstrated its operation at cryogenic temperature inside a cryo-module. The second, installed, also, in the FLASH linac to be tested with beam, measured a resolution of approximately 4 {mu}m over a dynamic range {+-} 5 mm in single bunch. (authors)

  14. Cavity Beam Position Monitor System for ATF2

    Energy Technology Data Exchange (ETDEWEB)

    Boogert, Stewart; /Oxford U., JAI; Boorman, Gary; /Oxford U., JAI; Swinson, Christina; /Oxford U., JAI; Ainsworth, Robert; /Royal Holloway, U. of London; Molloy, Stephen; /Royal Holloway, U. of London; Aryshev, Alexander; /KEK, Tsukuba; Honda, Yosuke; /KEK, Tsukuba; Tauchi, Toshiaki; /KEK, Tsukuba; Terunuma, Nobuhiro; /KEK, Tsukuba; Urakawa, Junji; /KEK, Tsukuba; Frisch, Josef; /SLAC; May, Justin; /SLAC; McCormick, Douglas; /SLAC; Nelson, Janice; /SLAC; Smith, Tonee; /SLAC; White, Glen; /SLAC; Woodley, Mark; /SLAC; Heo, Ae-young; /Kyungpook Natl. U.; Kim, Eun-San; /Kyungpook Natl. U.; Kim, Hyoung-Suk; /Kyungpook Natl. U.; Kim, Youngim; /Kyungpook Natl. U. /University Coll. London /Kyungpook Natl. U. /Fermilab /Pohang Accelerator Lab.

    2012-07-09

    The Accelerator Test Facility 2 (ATF2) in KEK, Japan, is a prototype scaled demonstrator system for the final focus required for a future high energy lepton linear collider. The ATF2 beam-line is instrumented with a total of 38 C and S band resonant cavity beam position monitors (CBPM) with associated mixer electronics and digitizers. The current status of the BPM system is described, with a focus on operational techniques and performance. The ATF2 C-band system is performing well, with individual CBPM resolution approaching or at the design resolution of 50 nm. The changes in the CBPM calibration observed over three weeks can probably be attributed to thermal effects on the mixer electronics systems. The CW calibration tone power will be upgraded to monitor changes in the electronics gain and phase. The four S-band CBPMs are still to be investigated, the main problem associated with these cavities is a large cross coupling between the x and y ports. This combined with the large design dispersion in that degion makes the digital signal processing difficult, although various techniques exist to determine the cavity parameters and use these coupled signals for beam position determination.

  15. Beam position monitor R&D for keV ion beams

    CERN Document Server

    Naveed, S; Nosych, A; Søby,L

    2013-01-01

    Beams of cooled antiprotons at keV energies shall be provided by the Ultra-low energy Storage Ring (USR) at the Facility for Low energy Antiproton and Ion Research (FLAIR) and the Extra Low ENergy Antiproton ring (ELENA) at CERN's Antiproton Decelerator (AD) facility. Both storage rings put challenging demands on the beam position monitoring (BPM) system as their capacitive pick-ups should be capable of determining the beam position of beams at low intensities and low velocities, close to the noise level of state-of-the-art electronics. In this contribution we describe the design and anticipated performance of BPMs for low-energy ion beams with a focus on the ELENA orbit measurement systems. We also present the particular challenges encountered in the numerical simulation of pickup response at very low beta values. Finally, we provide an outlook on how the implementation of faster algorithms for the simulation of BPM characteristics could potentially help speed up such studies considerably.

  16. Beam feasibility study of a collimator with in-jaw beam position monitors

    Science.gov (United States)

    Wollmann, Daniel; Nosych, Andriy A.; Valentino, Gianluca; Aberle, Oliver; Aßmann, Ralph W.; Bertarelli, Alessandro; Boccard, Christian; Bruce, Roderik; Burkart, Florian; Calvo, Eva; Cauchi, Marija; Dallocchio, Alessandro; Deboy, Daniel; Gasior, Marek; Jones, Rhodri; Kain, Verena; Lari, Luisella; Redaelli, Stefano; Rossi, Adriana

    2014-12-01

    At present, the beam-based alignment of the LHC collimators is performed by touching the beam halo with both jaws of each collimator. This method requires dedicated fills at low intensities that are done infrequently and makes this procedure time consuming. This limits the operational flexibility, in particular in the case of changes of optics and orbit configuration in the experimental regions. The performance of the LHC collimation system relies on the machine reproducibility and regular loss maps to validate the settings of the collimator jaws. To overcome these limitations and to allow a continuous monitoring of the beam position at the collimators, a design with jaw-integrated Beam Position Monitors (BPMs) was proposed and successfully tested with a prototype (mock-up) collimator in the CERN SPS. Extensive beam experiments allowed to determine the achievable accuracy of the jaw alignment for single and multi-turn operation. In this paper, the results of these experiments are discussed. The non-linear response of the BPMs is compared to the predictions from electromagnetic simulations. Finally, the measured alignment accuracy is compared to the one achieved with the present collimators in the LHC.

  17. Architecture of a silicon strip beam position monitor

    Energy Technology Data Exchange (ETDEWEB)

    Angstadt, R; Cooper, W; Demarteau, M; Green, J; Jakubowski, S; Prosser, A; Rivera, R; Turqueti, M; Utes, M [Fermilab, Wilson Rd. and Pine Street, Batavia, IL (United States); Cai, X, E-mail: utes@fnal.gov [Institute for High Energy Physics, 19 Yuquan Road, Shijingshan District, Beijing (China)

    2010-12-15

    A collaboration between Fermilab and the Institute for High Energy Physics (IHEP), Beijing, has developed a beam position monitor for the IHEP test beam facility. This telescope is based on 5 stations of silicon strip detectors having a pitch of 60 microns. The total active area of each layer of the detector is about 12x10 cm{sup 2}. Readout of the strips is provided through the use of VA1' ASICs mounted on custom hybrid printed circuit boards and interfaced to Adapter Cards via copper-over-kapton flexible circuits. The Adapter Cards amplify and level-shift the signal for input to the Fermilab CAPTAN data acquisition nodes for data readout and channel configuration. These nodes deliver readout of triggered events and temperature data to an analysis computer over gigabit Ethernet links.

  18. Architecture of a Silicon Strip Beam Position Monitor

    Energy Technology Data Exchange (ETDEWEB)

    Angstadt, R.; /Fermilab; Cooper, W.; /Fermilab; Demarteau, M.; /Fermilab; Green, J.; /Fermilab; Jakubowski, S.; /Fermilab; Prosser, A.; /Fermilab; Rivera, R.; /Fermilab; Turqueti, M.; /Fermilab; Utes, M.; /Fermilab; Cai, X.; /Beijing, Inst. High Energy Phys.

    2010-10-01

    A collaboration between Fermilab and the Institute for High Energy Physics (IHEP), Beijing, has developed a beam position monitor for the IHEP test beam facility. This telescope is based on 5 stations of silicon strip detectors having a pitch of 60 microns. The total active area of each layer of the detector is about 12 x 10 cm{sup 2}. Readout of the strips is provided through the use of VA1 ASICs mounted on custom hybrid printed circuit boards and interfaced to Adapter Cards via copper-over-kapton flexible circuits. The Adapter Cards amplify and level-shift the signal for input to the Fermilab CAPTAN data acquisition nodes for data readout and channel configuration. These nodes deliver readout and temperature data from triggered events to an analysis computer over gigabit Ethernet links.

  19. Architecture of a Silicon Strip Beam Position Monitor

    CERN Document Server

    Angstadt, R; Demarteau, M; Green, J; Jakubowski, S; Prosser, A; Rivera, R; Turqueti, M; Utes, M; Cai, Xiao

    2010-01-01

    A collaboration between Fermilab and the Institute for High Energy Physics (IHEP), Beijing, has developed a beam position monitor for the IHEP test beam facility. This telescope is based on 5 stations of silicon strip detectors having a pitch of 60 microns. The total active area of each layer of the detector is about 12x10 cm2. Readout of the strips is provided through the use of VA1` ASICs mounted on custom hybrid printed circuit boards and interfaced to Adapter Cards via copper-over-kapton flexible circuits. The Adapter Cards amplify and level-shift the signal for input to the Fermilab CAPTAN data acquisition nodes for data readout and channel configuration. These nodes deliver readout and temperature data from triggered events to an analysis computer over gigabit Ethernet links.

  20. Beam position pickup for antiprotons to the ISR

    CERN Multimedia

    CERN PhotoLab

    1981-01-01

    The Antiproton Project, launched for proton-antiproton collisions in the SPS (SPS collider), had a side-line for p-pbar collisions in the ISR. A new transfer line, TT6, was constructed to transport antiprotons from the 26 GeV PS to the injection line TT1 of ISR ring 2. Antiprotons were a scarce commodity. For setting up the lines, beam diagnostic devices in the antiproton path had to work reliably and precisely with just a few low-intensity pilot pules: single bunches of about 2x10**9 antiprotons every few hours. Electrostatic pickup electrodes were used to measure beam position. They could be mounted for measurement in the horizontal plane, as in this picture, or at 90 deg, for the vertical plane.

  1. Numerical simulation of the PEP-II beam position monitor

    Energy Technology Data Exchange (ETDEWEB)

    Kurita, N.; Martin, D.; Ng, C.-K.; Smith, S. [Stanford Linear Accelerator Center, Menlo Park, CA (United States); Weiland, T.

    1996-08-01

    We use MAFIA to analyze the PEP-II button-type beam position monitor (BPM). Employing proper termination of the BPM into a coaxial cable, the output signal at the BPM is determined. Thus the issues of signal sensitivity and power output can be addressed quantitatively, including all transient effects and wakefields. Besides this first quantitative analysis of a true BPM 3D structure, we find that internal resonant modes are a major source of high value narrow-band impedances. The effects of these resonances on coupled-bunch instabilities are discussed. An estimate of the power dissipation in the ceramic vacuum seal under high current operation is given. (author)

  2. Capacitive beam position monitors for the low-β beam of the Chinese ADS proton linac

    Science.gov (United States)

    Zhang, Yong; Wu, Jun-Xia; Zhu, Guang-Yu; Jia, Huan; Xue, Zong-Heng; Zheng, Hai; Xie, Hong-Ming; Kang, Xin-Cai; He, Yuan; Li, Lin; Denard, Jean Claude

    2016-02-01

    Beam Position Monitors (BPMs) for the low-β beam of the Chinese Accelerator Driven Subcritical system (CADS) Proton linac are of the capacitive pick-up type. They provide higher output signals than that of the inductive type. This paper will describe the design and tests of the capacitive BPM system for the low-β proton linac, including the pick-ups, the test bench and the read-out electronics. The tests done with an actual proton beam show a good agreement between the measurements and the simulations in the time domain. Supported by National Natural Science Foundation of China (11405240) and “Western Light” Talents Training Program of Chinese Academy of Sciences

  3. Analysis and control of the photon beam position at PLS-II

    Energy Technology Data Exchange (ETDEWEB)

    Ko, J.; Kim, I.-Y.; Kim, C.; Kim, D.-T.; Huang, J.-Y.; Shin, S., E-mail: tlssh@postech.ac.kr [POSTECH, Pohang, Kyungbuk 790-784 (Korea, Republic of)

    2016-02-18

    The variation of the photon beam position in a beamline, which is a critical issue for user experiments, is analyzed and corrected through the correlation link with the electron beam position in the storage ring. At third-generation light sources, the photon beam position stability is a critical issue for user experiments. In general, photon beam position monitors are developed to detect the real photon beam position, and the position is controlled by a feedback system in order to maintain the reference photon beam position. At Pohang Light Source II, a photon beam position stability of less than 1 µm r.m.s. was achieved for a user service period in the beamline, where the photon beam position monitor is installed. Nevertheless, a detailed analysis of the photon beam position data was necessary in order to ensure the performance of the photon beam position monitor, since it can suffer from various unknown types of noise, such as background contamination due to upstream or downstream dipole radiation, and undulator gap dependence. This paper reports the results of a start-to-end study of the photon beam position stability and a singular value decomposition analysis to confirm the reliability of the photon beam position data.

  4. The Beam Position System of the CERN Neutrino to Gran Sasso Proton Beam Line

    CERN Document Server

    Bogey, T

    2008-01-01

    The CERN Neutrino to Gran Sasso (CNGS) experiment uses 400GeV protons extracted from the SPS, which travel along 825 meters of beam line before reaching the CNGS target. This beam line is equipped with 23 BPMs capable of measuring both the horizontal and vertical position of the beam. The final BPM is linked to the target station and due to radiation constraints has been designed to work in air. This contribution will give an overview of the BPMs used in the transfer line. It will also provide a detailed explanation of their logarithmic amplifier based acquisition electronics, which consists of an autotriggered sequencer controlling an integrator, the A/D conversion and the Manchester encoded transmission of the digital data to the surface. At the surface the digital data is acquired using the Digital Acquisition Board (DAB) developed by TRIUMF (Canada) for the LHC BPM system. Results from both laboratory measurements and beam measurements during the 2006 CNGS run will also be presented.

  5. Digital Beam Position Monitor for the Happex Experiment

    International Nuclear Information System (INIS)

    The proposed HAPPEX experiment at CEBAF employs a three cavity monitor system for high-precision (1 mm), high-bandwidth (100 kHz) position measurements. This is performed using a cavity triplet consisting of two TM110-mode cavities (one each for X and Y planes) combined with a conventional TM-010-mode cavity for a phase and magnitude reference. Traditional systems have used the TM010 cavity output to directly down convert the BPM cavity signals to base band. The Multi-channel HAPPEX digital receiver simultaneously I/Q samples each cavity and extracts position using a CORDIC algorithm. The hardware design consists of a digital receiver daughter board and digital processor motherboard that resides in a VXI crate. The daughter board down converts 1.497 GHz signals from the TM010 cavity and X and Y signals from the TM110 cavities to 4 MHz, and extracts the quadrature digital signals. The motherboard processes this data and computes beam intensity and X-Y positions with a resolution of one mm, 100 kHz output bandwidth, and overall latency of ten microseconds. The results are available in both analog and digital format

  6. Digital beam position monitor for the HAPPEX experiment

    International Nuclear Information System (INIS)

    The proposed HAPPEX experiment at CEBAF employs a three cavity monitor system for high precision (1um), high bandwidth (100 kHz) position measurements. This is performed using a cavity triplet consisting of two TM110-mode cavities (one each for X and Y planes) combined with a conventional TM010-mode cavity for a phase and magnitude reference. Traditional systems have used the TM010 cavity output to directly down convert the BPM cavity signals to base band. The multi-channel HAPPEX digital receiver simultaneously I/Q samples each cavity and extracts position using a CORDIC algorithm. The hardware design consists of a RF receiver daughter board and a digital processor motherboard that resides in a VXI crate. The daughter board down converts 1.497 GHz signals from the TM010 cavity and X and Y signals from the TM110 cavities to 3 MHz and extracts the quadrature digital signals. The motherboard processes this data and computes beam intensity and X-Y positions with resolution of 1um, 100 kHz output bandwidth, and overall latency of 1us. The results are available in both the analog and digital format

  7. ROBUST POSITIONING OF LASER BEAMS USING PROPORTIONAL INTEGRAL DERIVATIVE AND BASED OBSERVER-FEEDBACK CONTROL

    OpenAIRE

    Kwabena A. Konadu; Sun Yi; Wonchang Choi; Taher Abu-Lebdeh

    2013-01-01

    High-precision positioning of laser beams has been a great challenge in industry due to inevitable existence of noise and disturbance. The work presented in this study addresses this problem by employing two different control strategies: Proportional Integral Derivative (PID) control and state feedback control with an observer. The control strategies are intended to stabilize the position of a laser beam on a Position Sensing Device (PSD) located on a Laser Beam Stabilization (or, laser beam ...

  8. Beam position stability in INDUS-2 storage ring

    International Nuclear Information System (INIS)

    To reach the high brightness objective of INDUS-2, one has to design a strong focusing optics where the beam emittance together with beam sizes at the insertion device must be very low. It is thus necessary to study the series noise sources-magnet-closed orbit distortion (COD) motion beam size and emittance variations

  9. Radiation-hard Beam Position Detector for Use in the Accelerator Dump Lines

    CERN Document Server

    Degtiarenko, Pavel; Popov, Vladimir

    2005-01-01

    Proper transport of the electron beam with over 0.5MW of power to the beam dump is a prerequisite for operations at Jefferson Lab. Operations has relied on imaging the beam on a beam viewer located at the entrance to the beam dump. The large beam size at the dump entrance, due to beam scattering in the experimental target, sometimes results in no observable image on the view-screen. Chemical vapor deposited silicon carbide (CVD) material with its large thermal conductivity and high melting point is well suited for surviving the thermal effects of beam exposure with this power density. We are exploring the CVD properties and how it can be used as a robust beam position monitor. Results of some beam tests with 0.5MW beams will be presented.

  10. Electromagnetic modeling of beam position and phase monitors for SNS linac

    Science.gov (United States)

    Kurennoy, Sergey S.

    2000-11-01

    Electromagnetic modeling of the beam position monitors (BPMs) for the Spallation Neutron Source (SNS) linac has been performed with MAFIA. The signal amplitudes and phases on the BPM electrodes are computed as functions of the beam transverse position using time-domain 3-D simulations with an ultra-relativistic beam. An analytical model is then applied to extrapolate the results to lower beam velocities. It is shown that while the signal phases on the individual electrodes for an off-axis beam can differ from those for a centered beam by a few degrees, the phase of the summed signal from all electrodes is insensitive to the beam transverse position inside the device. Based on the analysis results, an optimal BPM design with 4 one-end-shorted 60-degree electrodes has been chosen. It provides a very good linearity and sufficient signal power for both position and phase measurements, while satisfying the linac geometrical constrains and mechanical requirements.

  11. Power beams and their comparative positioning in advanced materials processing

    International Nuclear Information System (INIS)

    Power Beam Technology covering laser, electron and plasma beams belongs to a class of novel manufacturing techniques. Availability of high power density in localized area along with flexible-controllability of the process makes them attractive for material processing applications. The use of power beams in cutting, welding and melting has been known for over five decades. However, it is only recently that the use of power beams in non-thermal and non-equilibrium processing is emerging as an area of active interest. This paper addresses some of the issues related to the underlying principles of power beams, the comparative strengths and weaknesses of the different techniques and their implementation in processing environment. (author)

  12. Development of capacitive beam position, beam current and Schottky-signal monitors for the Cryogenic Storage Ring (CSR)

    International Nuclear Information System (INIS)

    In this thesis novel techniques based on capacitive pickups for the determination of the beam current, the beam position and the Schottky-signal in storage rings have been developed. Beam current measurements at the heavy ion storage ring TSR with a capacitive pickup have been found in very good agreement with the theory. Using this device the accurate measurement of beam currents at the TSR far below 1 μA is now possible. This method will also be used at the Cryogenic Storage Ring (CSR) at which beam currents in the range of 1 nA-1 μA are expected. For the first time, position measurements with a resonant amplifier system for capacitive pickups have been examined at the TSR for later use of this technique in the CSR. With this method an increased signal-to-noise ratio can be achieved using a parallel inductance. A comparison with measurements using the rest gas beam profile monitor has shown very good agreement even at very low intensities. Experiments with the cryo-capable electronics for the CSR beam position monitors have shown an achievable quality factor of Q=500, resulting in the prospect of precise position measurements at the CSR even at very low beam currents. The CSR Schottky-Pickup will also be equipped with a resonant amplifier system with a comparable quality factor. An estimation of the signal-to-noise ratio suggests a detection limit of a few protons. (orig.)

  13. Calibration of an Advanced Photon Source linac beam position monitor used for positron position measurement of a beam containing both positrons and electrons

    International Nuclear Information System (INIS)

    The Advanced Photon Source (APS) linac beam position monitors can be used to monitor the position of a positron beam also containing electrons. To accomplish this task, both the signal at the bunching frequency of 2856 MHz and the signal at 2 x 2856 MHz are acquired and processed for each stripline. The positron beam position is obtained by forming a linear combination of both 2856- and 5712-MHz signals for each stripline and then performing the standard difference over sum computation. The required linear combination of the 2856- and 5712-MHz signals depends on the electrical calibration of each stripline/cable combination. In this paper, the calibration constants for both 2856-MHz and 5712-MHz signals for each stripline are determined using a pure beam of electrons. The calibration constants are obtained by measuring the 2856- and 5712-MHz stripline signals at various electron beam currents and positions. Finally, the calibration constants measured using electrons are used to determine positron beam position for the mixed beam case

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

    Energy Technology Data Exchange (ETDEWEB)

    Gilpatrick, J.D.; Khan, S.; Kraemer, D. [BESSY II, Berlin (Germany)

    1996-11-01

    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 < 1- to > 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.

  15. Digital feed back control for radial beam position

    International Nuclear Information System (INIS)

    In the development of wide spread large scale distributed digital control systems, there is a requirement to automate small processes like radial beam control which will not only improve the beam quality but will also add local intelligence. Hence use is made here of digital control principles for such applications. The work concerned with the radial beam control discussed in this report has been developed for ISIS at RAL. The structure of the report is hence inclined more towards the local hardware system. The general feed back loop techniques can also be implemented for other control purpose. For instance, the author has successfully tested similar techniques to minimise the RF cavity tuning error, where the improvement in performance could not be matched by the analogue loop. A description of the RF cavity tuning programme and the associated experimental results will be published as a local paper for ISIS division. (author)

  16. High-Precision Resonant Cavity Beam Position, Emittance And Third-Moment Monitors

    Energy Technology Data Exchange (ETDEWEB)

    Barov, N.; Kim, J.S.; Weidemann, A.W.; /FARTECH, San Diego; Miller, R.H.; Nantista, C.D.; /SLAC

    2006-03-14

    Linear colliders and FEL facilities need fast, nondestructive beam position and profile monitors to facilitate machine tune-up, and for use with feedback control. FAR-TECH, Inc., in collaboration with SLAC, is developing a resonant cavity diagnostic to simultaneously measure the dipole, quadrupole and sextupole moments of the beam distribution. Measurements of dipole and quadrupole moments at multiple locations yield information about beam orbit and emittance. The sextupole moment can reveal information about beam asymmetry which is useful in diagnosing beam tail deflections caused by short-range dipole wakefields. In addition to the resonance enhancement of a single-cell cavity, use of a multi-cell standing-wave structure further enhances signal strength and improves the resolution of the device. An estimated resolution is better than 1 {micro}m in rms beam size and better than 1 nm in beam position.

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

    International Nuclear Information System (INIS)

    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

  18. LHC Collimators with Embedded Beam Position Monitors: a New Adbanced Mechanical Design

    CERN Document Server

    Dallocchio, A; Boccard, C; Carra, F; Gasior, M; Gentini, L; Timmins, M

    2011-01-01

    The LHC collimation system, ensuring both functions of beam cleaning and machine protection, is potentially submitted to high-energy beam impacts. Currently the collimators setup is performed by monitoring beam losses generated by the collimator jaws when approaching the particle beam. This procedure is applied to all LHC collimators (almost one hundred), taking several hours, and needs to be repeated if beam settings change significantly. Furthermore, during the beam-based alignment, the LHC tertiary collimators are potentially exposed to abnormal losses entailing possible damage to their tungsten jaws. To improve the efficiency of the machine operation and better control the particle beam a new advanced design embedding Beam Position Monitors (BPM) into the movable collimator jaws has been developed. This paper describes the mechanical design of various types of future collimators with embedded BPMs. Experimental measurements performed on a simplified functional prototype installed in the CERN SPS showed th...

  19. Long bunch trains measured using a prototype cavity beam position monitor for the Compact Linear Collider

    Science.gov (United States)

    Cullinan, F. J.; Boogert, S. T.; Farabolini, W.; Lefevre, T.; Lunin, A.; Lyapin, A.; Søby, L.; Towler, J.; Wendt, M.

    2015-11-01

    The Compact Linear Collider (CLIC) requires beam position monitors (BPMs) with 50 nm spatial resolution for alignment of the beam line elements in the main linac and beam delivery system. Furthermore, the BPMs must be able to make multiple independent measurements within a single 156 ns long bunch train. A prototype cavity BPM for CLIC has been manufactured and tested on the probe beam line at the 3rd CLIC Test Facility (CTF3) at CERN. The transverse beam position is determined from the electromagnetic resonant modes excited by the beam in the two cavities of the pickup, the position cavity and the reference cavity. The mode that is measured in each cavity resonates at 15 GHz and has a loaded quality factor that is below 200. Analytical expressions for the amplitude, phase and total energy of signals from long trains of bunches have been derived and the main conclusions are discussed. The results of the beam tests are presented. The variable gain of the receiver electronics has been characterized using beam excited signals and the form of the signals for different beam pulse lengths with the 2 /3 ns bunch spacing has been observed. The sensitivity of the reference cavity signal to charge and the horizontal position signal to beam offset have been measured and are compared with theoretical predictions based on laboratory measurements of the BPM pickup and the form of the resonant cavity modes as determined by numerical simulation. Finally, the BPM was calibrated so that the beam position jitter at the BPM location could be measured. It is expected that the beam jitter scales linearly with the beam size and so the results are compared to predicted values for the latter.

  20. A new measurement method of electrode gains for orthogonal symmetric type beam position monitor

    CERN Document Server

    Zou, J Y; Yang, Y L; Sun, B G; Zhou, Z R; Luo, Q; Lu, P; Xu, H L

    2014-01-01

    The new beam position monitor (BPM) system of the injector at the upgrade project of Hefei Light Source (HLS II) has 19 stripline beam position monitors. Most consist of four orthogonal symmetric stripline electrodes. The differences in electronic gain and mismachining tolerance can cause the change of the beam response of the BPM electrodes. This variation will couple the two measured horizontal positions in order to bring the measuring error. To alleviate this effect, a new technique to measure the relative response of the four electrodes has been developed. It is irrelevant to the beam charge and the related coefficient can be theoretical calculated. The effect of electrodes coupling on this technique is analyzed. The calibration data is used to fit the gain for all 19 injector beam position monitors. The results show the standard deviation of the distribution of measured gains is about 5%.

  1. SQUID-based beam position monitoring for proton EDM experiment

    Science.gov (United States)

    Haciomeroglu, Selcuk

    2014-09-01

    One of the major systematic errors in the proton EDM experiment is the radial B-field, since it couples the magnetic dipole moment and causes a vertical spin precession. For a proton with EDM at the level of 10-29 e.cm, 0.22 pG of B-field and 10.5 MV/m of E-field cause same vertical spin precession. On the other hand, the radial B-field splits the counter-rotating beams depending on the vertical focusing strength in the ring The magnetic field due to this split modulated at a few kHz can be measured by a SQUID-magnetometer. This measurement requires the B-field to be kept less than 1 nT everywhere around the ring using shields of mu-metal and aluminum layers. Then, the SQUID measurements involve noise from three sources: outside the shields, the shields themselves and the beam. We study these three sources of noise using an electric circuit (mimicking the beam) inside a magnetic shielding room which consists two-layers of mu-metal and an aluminum layer.

  2. Control of secondary electrons from ion beam impact using a positive potential electrode

    Science.gov (United States)

    Crowley, T. P.; Demers, D. R.; Fimognari, P. J.

    2016-11-01

    Secondary electrons emitted when an ion beam impacts a detector can amplify the ion beam signal, but also introduce errors if electrons from one detector propagate to another. A potassium ion beam and a detector comprised of ten impact wires, four split-plates, and a pair of biased electrodes were used to demonstrate that a low-voltage, positive electrode can be used to maintain the beneficial amplification effect while greatly reducing the error introduced from the electrons traveling between detector elements.

  3. A compact and portable X-ray beam position monitor using Medipix3

    OpenAIRE

    O. Rico-Alvarez, A. Kachatkou, J. Marchal, B. Willis, K. Sawhney, N. Tartoni and R.G. van Silfhout

    2014-01-01

    The present work reports on the design and implementation of a novel portable Xraybeam diagnostics (XBPM) device. The device is transparent to the X-ray beam and provides real-time measurements of beam position, intensity, and size. The measurement principle is based on a pinhole camera which records scattered radiation from a Kapton foil which is placed in the beam path. The use of hybrid detectors (Medipix3) that feature a virtually noiseless readout system with capability of single photon ...

  4. Micro-vibrating spatial filters-induced beam positioning stability in large laser system

    Institute of Scientific and Technical Information of China (English)

    Fang Liu; Jianqiang Zhu; Jia Xu; Quanyuan Shan; Kun Xiao; Xuejie Zhang

    2012-01-01

    A dynamic beam propagation model of micro-vibrating spatial filters in inertial confinement fusion (ICF) facilities is built based on the additional beam in SG-Ⅱ facility.The transfer matrix is then deduced,and the sensitivities of the beam positioning to the pellet in the target area to the vibrations of every spatial filter are analyzed,which indicates that the vibrations of spatial filters in the pre-amplify zone has less effects on beam positioning stability at the target.In addition,the vibrations of spatial filters in the main amplify zone dominates the beam positioning stability of the target,especially the vibration of the spatial filter SF7.

  5. Transport and Non-Invasive Position Detection of Electron Beams from Laser-Plasma Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Osterhoff, Jens; Sokollik, Thomas; Nakamura, Kei; Bakeman, Michael; Weingartner, R; Gonsalves, Anthony; Shiraishi, Satomi; Lin, Chen; vanTilborg, Jeroen; Geddes, Cameron; Schroeder, Carl; Esarey, Eric; Toth, Csaba; DeSantis, Stefano; Byrd, John; Gruner, F; Leemans, Wim

    2011-07-20

    The controlled imaging and transport of ultra-relativistic electrons from laser-plasma accelerators is of crucial importance to further use of these beams, e.g. in high peak-brightness light sources. We present our plans to realize beam transport with miniature permanent quadrupole magnets from the electron source through our THUNDER undulator. Simulation results demonstrate the importance of beam imaging by investigating the generated XUV-photon flux. In addition, first experimental findings of utilizing cavity-based monitors for non-invasive beam-position measurements in a noisy electromagnetic laser-plasma environment are discussed.

  6. Multipass beam position, profile, and polarization measurements using intense photon target

    Energy Technology Data Exchange (ETDEWEB)

    Karabekov, I.P.; Neil, G.R. [Continuous Electron Beam Accelerator Facility, Newport News, VA (United States); Karabekian, S.; Musakhanian, V. [Yerevan Physics Inst., Erevan (Armenia)

    1994-05-01

    The Compton scattering of a circularly polarized laser beam condensed by an optical resonator can be used for multipass measurement of beam profile, position, and polarization in CEBAF`s 250-m-long linac straight sections. The position and profile of the beam will be measured with an accuracy of {approximately}10 {mu}m in about 200 seconds and beam polarization with 10% accuracy in 100 seconds when the lowest beam energy is 500 MeV and the beam current is 100 {mu}A. For higher energies the times for measurement are much less. The photon target is within an optical resonator having a quality factor of 50. The Nd:Yag 5 W CW laser photon beam at wavelength {lambda} = 0.532 nm will have a waist {omega}{sub o} {approximately}30 {mu}m and a Rayleigh range of about 10 mm. Scanning the electron beams in the linac sections by this photon beam at a crossing angle of 0.1 rad will send to a proportional detector installed after the spreader magnet scattered photons with energies sharply correlated with the energy of the electrons.

  7. Monitoring the electron beam position at the TESLA test facility free electron laser

    Energy Technology Data Exchange (ETDEWEB)

    Kamps, T.

    2000-06-14

    The operation of a free electron laser working in the Self Amplified Spontaneous Emission mode (SASE FEL) requires the electron trajectory to be aligned with very high precision in overlap with the photon beam. In order to ensure this overlap, one module of the SASE FEL undulator at the TESLA Test Facility (TTF) is equipped with a new type of waveguide beam position monitor (BPM). Four waveguides are arranged symmetrically around the beam pipe, each channel couples through a small slot to the electromagnetic beam field. The induced signal depends on the beam intensity and on the transverse beam position in terms of beam-to-slot distance. With four slot--waveguide combinations a linear position sensitive signal can be achieved, which is independent of the beam intensity. The signals transduced by the slots are transferred by ridged waveguides through an impedance matching stage into a narrowband receiver tuned to 12 GHz. The present thesis describes design, tests, and implementation of this new type of BPM. (orig.)

  8. Monitoring the electron beam position at the TESLA test facility free electron laser

    International Nuclear Information System (INIS)

    The operation of a free electron laser working in the Self Amplified Spontaneous Emission mode (SASE FEL) requires the electron trajectory to be aligned with very high precision in overlap with the photon beam. In order to ensure this overlap, one module of the SASE FEL undulator at the TESLA Test Facility (TTF) is equipped with a new type of waveguide beam position monitor (BPM). Four waveguides are arranged symmetrically around the beam pipe, each channel couples through a small slot to the electromagnetic beam field. The induced signal depends on the beam intensity and on the transverse beam position in terms of beam-to-slot distance. With four slot--waveguide combinations a linear position sensitive signal can be achieved, which is independent of the beam intensity. The signals transduced by the slots are transferred by ridged waveguides through an impedance matching stage into a narrowband receiver tuned to 12 GHz. The present thesis describes design, tests, and implementation of this new type of BPM. (orig.)

  9. Evaluation of an optical beam-position-monitor system with closed-loop steering capabilities

    Science.gov (United States)

    Bissen, Mark; Rogers, Greg; Wood, William; Eisert, Dave; Kleman, K. J.; Winter, William; Höchst, Hartmut

    1994-08-01

    Imaging the synchrotron source profile onto the entrance slit of a monochromator provides a stable and reproducible energy calibration which is independent of the absolute position and drift of the electron beam. Potential electron-beam motions occurring during a fill result in a loss of flux through the beamline. We have implemented two independent beam position monitors which can be used as sensors to steer the vertical entrance mirror in order to maintain a maximum flux through a spherical grating varied line-spacing monochromator beamline. The system consists of a slotted plate photodiode which intercepts 2 mrad of synchrotron radiation next to the entrance mirror and a detector utilizing the photocurrents generated at the jaws of the entrance-slit assembly. Both monitors have a wide linear response range with a vertical position resolution of beam position monitors allows an easy check on the mechanical and thermal stability of the entrance optical system as well as on the reproducibility and long-term fluctuations of the electron-beam source during user shifts. We will discuss the performance of the optical beam-position-monitor system and its implementation as a sensor in a closed-loop feedback system to maintain maximum flux through the beamline.

  10. Beam Position Reconstruction for the g2p Experiment in Hall A at Jefferson Lab

    CERN Document Server

    Zhu, Pengjia; Allison, Trent; Badman, Toby; Camsonne, Alexandre; Chen, Jian-ping; Cummings, Melissa; Gu, Chao; Huang, Min; Liu, Jie; Musson, John; Slifer, Karl; Sulkosky, Vincent; Ye, Yunxiu; Zhang, Jixie; Zielinski, Ryan

    2015-01-01

    Beam-line equipment was upgraded for experiment E08-027 (g2p) in Hall A at Jefferson Lab. Two beam position monitors (BPMs) were necessary to measure the beam position and angle at the target. A new BPM receiver was designed and built to handle the low beam currents (50-100 nA) used for this experiment. Two new super-harps were installed for calibrating the BPMs. In addition to the existing fast raster system, a slow raster system was installed. Before and during the experiment, these new devices were tested and debugged, and their performance was also evaluated. In order to achieve the required accuracy (1-2 mm in position and 1-2 mrad in angle at the target location), the data of the BPMs and harps were carefully analyzed, as well as reconstructing the beam position and angle event by event at the target location. The calculated beam position will be used in the data analysis to accurately determine the kinematics for each event.

  11. Beam position reconstruction for the g2p experiment in Hall A at Jefferson lab

    Science.gov (United States)

    Zhu, Pengjia; Allada, Kalyan; Allison, Trent; Badman, Toby; Camsonne, Alexandre; Chen, Jian-ping; Cummings, Melissa; Gu, Chao; Huang, Min; Liu, Jie; Musson, John; Slifer, Karl; Sulkosky, Vincent; Ye, Yunxiu; Zhang, Jixie; Zielinski, Ryan

    2016-02-01

    Beam-line equipment was upgraded for experiment E08-027 (g2p) in Hall A at Jefferson Lab. Two beam position monitors (BPMs) were necessary to measure the beam position and angle at the target. A new BPM receiver was designed and built to handle the low beam currents (50-100 nA) used for this experiment. Two new super-harps were installed for calibrating the BPMs. In addition to the existing fast raster system, a slow raster system was installed. Before and during the experiment, these new devices were tested and debugged, and their performance was also evaluated. In order to achieve the required accuracy (1-2 mm in position and 1-2 mrad in angle at the target location), the data of the BPMs and harps were carefully analyzed, as well as reconstructing the beam position and angle event by event at the target location. The calculated beam position will be used in the data analysis to accurately determine the kinematics for each event.

  12. Development of digital down conversion based digital beam position monitor for Indus-1

    International Nuclear Information System (INIS)

    Indus-1 is a 450 MeV synchrotron radiation source (SRS) at RRCAT Indore. For beam position measurement, four button type beam position indicators (BPls) are installed in Indus-I. A digital down conversion (DDC) algorithm based digital beam position monitor (DBPM) has been developed. Xilinx make board having Virtex-t FPGA has been used for implementation of DBPM system. The RF frequency of Indus-1 is 31.613 MHz. This DBPM processes 31.613 MHz pickup signals of beam position indicator by sampling it with 14 bit ADC at 28 MHz clock. The DDC also works at same clock of 28 MHz and generates position output. The output data rate of 10 kSPS and bandwidth of ∼ 2 kHz has been achieved by this system. System has been tested successfully in lab on calibration bench with simulated beam signals. System has also been tested in field. The design details and implementation aspects are discussed in this paper. (author)

  13. Beam position diagnostics with higher order modes in third harmonic superconducting accelerating cavities

    CERN Document Server

    Zhang, P; Baboi, Nicoleta

    2012-01-01

    Higher order modes (HOM) are electromagnetic resonant fields. They can be excited by an electron beam entering an accelerating cavity, and constitute a component of the wakefield. This wakefield has the potential to dilute the beam quality and, in the worst case, result in a beam-break-up instability. It is therefore important to ensure that these fields are well suppressed by extracting energy through special couplers. In addition, the effect of the transverse wakefield can be reduced by aligning the beam on the cavity axis. This is due to their strength depending on the transverse offset of the excitation beam. For suitably small offsets the dominant components of the transverse wakefield are dipole modes, with a linear dependence on the transverse offset of the excitation bunch. This fact enables the transverse beam position inside the cavity to be determined by measuring the dipole modes extracted from the couplers, similar to a cavity beam position monitor (BPM), but requires no additional vacuum instrum...

  14. Experimental study of delayed positive feedback control for a flexible beam

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Recently, some researches indicate that positive feedback can benefit the control if appropriate time delay is intentionally introduced into control system. However, most work is theoretical one but few are experimental. This paper presents theoretical and experimental studies of delayed positive feedback control technique using a flexible beam as research object. The positive feedback weighting coefficient is designed by using the optimal control method. The available time delay is determined by analyzing ...

  15. The positive charging effect of dielectric films irradiated by a focused electron beam

    International Nuclear Information System (INIS)

    Space charge and surface potential profiles are investigated with numerical simulation for dielectric films of SiO2 positively charged by a focused electron beam. By combining the Monte Carlo method and the finite difference method, the simulation is preformed with a newly developed comprehensive two-dimensional model including electron scattering, charge transport and trapping. Results show that the space charge is distributed positively, like a semi-ellipsoid, within a high-density region of electrons and holes, but negatively outside the region due to electron diffusion along the radial and beam incident directions. Simultaneously, peak positions of the positive and negative space charge densities shift outwards or downwards with electron beam irradiation. The surface potential, along the radial direction, has a nearly flat-top around the center, abruptly decreases to negative values outside the high-density region and finally increases to zero gradually. Influences of electron beam and film parameters on the surface potential profile in the equilibrium state are also shown and analyzed. Furthermore, the variation of secondary electron signal of a large-scale integration sample positively charged in scanning electron microscopic observation is simulated and validated by experiment.

  16. Beam position diagnostics with higher order modes in third harmonic superconducting accelerating cavities

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Pei

    2013-02-15

    Higher order modes (HOM) are electromagnetic resonant fields. They can be excited by an electron beam entering an accelerating cavity, and constitute a component of the wakefield. This wakefield has the potential to dilute the beam quality and, in the worst case, result in a beam-break-up instability. It is therefore important to ensure that these fields are well suppressed by extracting energy through special couplers. In addition, the effect of the transverse wakefield can be reduced by aligning the beam on the cavity axis. This is due to their strength depending on the transverse offset of the excitation beam. For suitably small offsets the dominant components of the transverse wakefield are dipole modes, with a linear dependence on the transverse offset of the excitation bunch. This fact enables the transverse beam position inside the cavity to be determined by measuring the dipole modes extracted from the couplers, similar to a cavity beam position monitor (BPM), but requires no additional vacuum instrumentation. At the FLASH facility in DESY, 1.3 GHz (known as TESLA) and 3.9 GHz (third harmonic) cavities are installed. Wakefields in 3.9 GHz cavities are significantly larger than in the 1.3 GHz cavities. It is therefore important to mitigate the adverse effects of HOMs to the beam by aligning the beam on the electric axis of the cavities. This alignment requires an accurate beam position diagnostics inside the 3.9 GHz cavities. It is this aspect that is focused on in this thesis. Although the principle of beam diagnostics with HOM has been demonstrated on 1.3 GHz cavities, the realization in 3.9 GHz cavities is considerably more challenging. This is due to the dense HOM spectrum and the relatively strong coupling of most HOMs amongst the four cavities in the third harmonic cryo-module. A comprehensive series of simulations and HOM spectra measurements have been performed in order to study the modal band structure of the 3.9 GHz cavities. The dependencies of

  17. A bunch-by-bunch beam position monitor based on scope embedded IOC

    International Nuclear Information System (INIS)

    A bunch-by-bunch beam position monitor system, based on a broadband oscilloscope embedded EPICS IOC, has been developed at SSRF to study the beam instabilities driven by the wake-field effects. The horizontal and vertical beam positions of each bunch could be located independently in this system by using the original signals from the button-type pickups on the storage ring. In this article, we report the hardware and software architecture of this system. The bunch-by-bunch data of the storage ring are used to evaluate performance of the system. Dependency of the tune, and the betatron oscillation amplitude of different bunch on the corresponding bunch ID, is also detected. The system is an effective tool for machine-study of SSRF. (authors)

  18. Beam position monitoring system based on EPICS and MATLAB image processing technique

    International Nuclear Information System (INIS)

    An optical X-ray beam position monitoring system has been established on Shanghai Synchrotron Radiation Facility (SSRF). The software for control, data acquisition and data processing is based on EPICS. It can capture and process a real time image to give the center position and spatial distribution of synchrotron radiations. The system has been used on SSRF beamlines and the experimental results show that the design specifications have been achieved. (authors)

  19. AN EXISTENCE THEOREM OF POSITIVE SOLUTIONS FOR ELASTIC BEAM EQUATION WITH BOTH FIXED END-POINTS

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    By using the degree theory on cone an existence theorem of positive solution for a class of fourth-order two-point BVP's is obtained. This class of BVP's usually describes the deformation of the elastic beam with both fixed end-points.

  20. A novel electromagnetic design and a new manufacturing process for the cavity BPM (Beam Position Monitor)

    Science.gov (United States)

    Dal Forno, Massimo; Craievich, Paolo; Baruzzo, Roberto; De Monte, Raffaele; Ferianis, Mario; Lamanna, Giuseppe; Vescovo, Roberto

    2012-01-01

    The Cavity Beam Position Monitor (BPM) is a beam diagnostic instrument which, in a seeded Free Electron Laser (FEL), allows the measurement of the electron beam position in a non-destructive way and with sub-micron resolution. It is composed by two resonant cavities called reference and position cavity, respectively. The measurement exploits the dipole mode that arises when the electron bunch passes off axis. In this paper we describe the Cavity BPM that has been designed and realized in the context of the FERMI@Elettra project [1]. New strategies have been adopted for the microwave design, for both the reference and the position cavities. Both cavities have been simulated by means of Ansoft HFSS [2] and CST Particle Studio [3], and have been realized using high precision lathe and wire-EDM (Electro-Discharge) machine, with a new technique that avoids the use of the sinker-EDM machine. Tuners have been used to accurately adjust the working frequencies for both cavities. The RF parameters have been estimated, and the modifications of the resonant frequencies produced by brazing and tuning have been evaluated. Finally, the Cavity BPM has been installed and tested in the presence of the electron beam.

  1. A novel electromagnetic design and a new manufacturing process for the cavity BPM (Beam Position Monitor)

    Energy Technology Data Exchange (ETDEWEB)

    Dal Forno, Massimo, E-mail: massimo.dalforno@phd.units.it [Department of Industrial Engineering and Information Technology, University of Trieste (Italy); Craievich, Paolo, E-mail: paolo.craievich@elettra.trieste.it [Sicrotrone Trieste S.C.p.A., Basovizza, Trieste (Italy); Baruzzo, Roberto [Cinel Strumenti Scientifici s.r.l., Vigonza, Padova (Italy); De Monte, Raffaele; Ferianis, Mario [Sicrotrone Trieste S.C.p.A., Basovizza, Trieste (Italy); Lamanna, Giuseppe [Cinel Strumenti Scientifici s.r.l., Vigonza, Padova (Italy); Vescovo, Roberto [Department of Industrial Engineering and Information Technology, University of Trieste (Italy)

    2012-01-11

    The Cavity Beam Position Monitor (BPM) is a beam diagnostic instrument which, in a seeded Free Electron Laser (FEL), allows the measurement of the electron beam position in a non-destructive way and with sub-micron resolution. It is composed by two resonant cavities called reference and position cavity, respectively. The measurement exploits the dipole mode that arises when the electron bunch passes off axis. In this paper we describe the Cavity BPM that has been designed and realized in the context of the FERMI-Elettra project . New strategies have been adopted for the microwave design, for both the reference and the position cavities. Both cavities have been simulated by means of Ansoft HFSS and CST Particle Studio , and have been realized using high precision lathe and wire-EDM (Electro-Discharge) machine, with a new technique that avoids the use of the sinker-EDM machine. Tuners have been used to accurately adjust the working frequencies for both cavities. The RF parameters have been estimated, and the modifications of the resonant frequencies produced by brazing and tuning have been evaluated. Finally, the Cavity BPM has been installed and tested in the presence of the electron beam.

  2. Engineering design and study of the beam position accuracy in the "Riesenrad" ion gantry

    CERN Document Server

    Reimoser, S A

    2001-01-01

    Beams of carbon ions are particularly well suited for radiotherapy. Their physical properties allow the 3D-conformal tumour irradiation with a sub-millimetre precision, provided that the beam is delivered by a rotating gantry equipped with a pencil-beam scanning system. However, the expected size and weight of such a carbon-ion gantry together with the requirement to direct the beam to the patient with an extreme position accuracy has so far prevented its realisation and stimulated the search for alternative solutions. One of them, the "Riesenrad" ion gantry, is introduced in the present paper. In contrast to conventional isocentric gantries, the main bending magnet of the Riesenrad is placed on the axis of gantry rotation, hence minimising the moment of inertia of the mobile structure and maximising its rigidity. The treatment cabin is smoothly moved towards the desired treatment position by a system that is mechanically de-coupled from the gantry. The engineering design as well as some aspects of the beam t...

  3. Dual AC Dipole Excitation for the Measurement of Magnetic Multipole Strength from Beam Position Monitor Data

    Energy Technology Data Exchange (ETDEWEB)

    M. Spata, G.A. Krafft

    2011-09-01

    An experiment was conducted at Jefferson Lab's Continuous Electron Beam Accelerator Facility to develop a technique for characterizing the nonlinear fields of the beam transport system. Two air-core dipole magnets were simultaneously driven at two different frequencies to provide a time-dependent transverse modulation of the electron beam. Fourier decomposition of beam position monitor data was then used to measure the amplitude of these frequencies at different positions along the beamline. For a purely linear transport system one expects to find solely the frequencies that were applied to the dipoles with amplitudes that depend on the phase advance of the lattice. In the presence of nonlinear fields one expects to also find harmonics of the driving frequencies that depend on the order of the nonlinearity. The technique was calibrated using one of the sextupole magnets in a CEBAF beamline and then applied to a dipole to measure the sextupole and octupole strength of the magnet. A comparison is made between the beam-based measurements, results from TOSCA and data from our Magnet Measurement Facility.

  4. Beam Position and Phase Monitors Characterized and Installed in the LANSCE CCL

    Energy Technology Data Exchange (ETDEWEB)

    Gilpatrick, John D [Los Alamos National Laboratory; Kutac, Vincent G. [Los Alamos National Laboratory; Martinez, Derwin [Los Alamos National Laboratory; McCrady, Rodney C. [Los Alamos National Laboratory; O' Hara, James F. [Los Alamos National Laboratory; Olivas, Felix R. [Los Alamos National Laboratory; Shurter, Robert B. [Los Alamos National Laboratory; Watkins, Heath A. [Los Alamos National Laboratory

    2012-04-11

    The Los Alamos Neutron Science Center - Risk Mitigation Project is in the process of replacing older Coupled-Cavity-Linac (CCL) Beam-Position Monitors (BPMs) with newer Beam Position and Phase Monitors (BPPMs) and their associated electronics and cable plants. In many locations, these older BPMs include a separate Delta-T loop for measuring the beam's central phase and energy. Thirty-one BPPMs have been installed and many have monitored the charged particle beam. The installation of these newer BPPMs is the first step to installing complete BPPM measurement systems. Prior to the installation, a characterization of each BPPM took place. The characterization procedure includes a mechanical inspection, a vacuum testing, and associated electrical tests. The BPPM electrical tests for all four electrodes include contact resistance measurements, Time Domain Reflectometer (TDR) measurements, relative 201.25-MHz phase measurements, and finally a set of position-sensitive mapping measurements were performed which included associated fitting routines. This paper will show these data for a typical characterized BPPM.

  5. A Method to Calibrate Beam Position Monitor at HLS 200 MeV LINAC

    CERN Document Server

    Li, Ji-Hao; He, Duo-hui; Jin, Kai; Lu, Ping; Sun Bao Gen; Wang, Jianping; Wang, Yong; Zheng, P

    2005-01-01

    In order to improve injection efficiency of HLS 200Mev LINAC, we redesign a new strip line beam position monitor system, which is consisted of a strip line structure and a signal processing system. We decide on an online calibration method based on beam to find out the geometry centre displacement and relative gain offset. Before the BPM testing bench has been prepared, we make a simulation based on the model accounted for all factors influencing signal amplitudes and get the calibrating results. At last, we analyze the nonlinearity effect on the calibration results.

  6. A wire scanner system for characterizing the BNL energy recovery LINAC beam position monitor system

    Energy Technology Data Exchange (ETDEWEB)

    Michnoff R.; Biscardi, C.; Cerniglia, P.; Degen, C.; Gassner, D.; Hoff, L.; Hulsart, R.

    2012-04-15

    A stepper motor controlled wire scanner system has recently been modified to support testing of the Brookhaven National Laboratory (BNL) Collider-Accelerator department's Energy Recovery Linac (ERL) beam position monitor (BPM) system. The ERL BPM consists of four 9.33 mm diameter buttons mounted at 90 degree spacing in a cube with 1.875 inch inside diameter. The buttons were designed by BNL and fabricated by Times Microwave Systems. Libera brilliance single pass BPM electronic modules with 700 MHz bandpass filter, manufactured by Instrumentation Technologies, will be used to measure the transverse beam positions at 14 locations around the ERL. The wire scanner assembly provides the ability to measure the BPM button response to a pulsed wire, and evaluate and calibrate the Libera position measurement electronics. A description of the wire scanner system and test result data will be presented.

  7. Nanoscale Soldering of Positioned Carbon Nanotubes using Highly Conductive Electron Beam Induced Gold Deposition

    DEFF Research Database (Denmark)

    Madsen, Dorte Nørgaard; Mølhave, Kristian; Mateiu, Ramona Valentina;

    2003-01-01

    We have developed an in-situ method for controlled positioning of carbon nanotubes followed by highly conductive contacting of the nanotubes, using electron beam assisted deposition of gold. The positioning and soldering process takes place inside an Environmental Scanning Electron Microscope (E...... in a carbon matrix. Nanoscale soldering of multi-walled carbon nanotubes (MWNT) onto microelectrodes was achieved by deposition of a conducting gold line across a contact point between nanotube and electrode. The solderings were found to be mechanically stronger than the carbon nanotubes. We have positioned...

  8. Application of the Same Beam Interferometry Measurement in Relative Position Determination on Lunar Surface

    Directory of Open Access Journals (Sweden)

    HUANG Anyi

    2015-09-01

    Full Text Available Based on the principle and observation model of the same beam interferometry measurement, observation equations of differential time delay and time delay rate for targets on lunar surface are proposed. Restriction of appointed height and digital lunar height model is introduced and a Kalman filter with restriction to determine the relative position is put forward. By data simulation, the arithmetic is then validated and evaluated, which could fleetly and accurately determine the relative position between rover and lander. Low precision of the lander's position is required in the calculation.

  9. Measurement of the mean radial position of a lead ion beam in the CERN PS

    CERN Document Server

    Belleman, J; González, J; Johnston, S; Schulte, E C; Thivent, E

    1996-01-01

    The intensity of the lead ion beam in the PS, nominally 4×108 charges of Pb53+ per bunch, is too low for the closed orbit measurement system. However, for successful acceleration it is sufficient to know the mean radial position (MRP). A system was thus designed for simultaneous acquisition of revolution frequency and magnetic field. The frequency measurement uses a direct digital synthesiser (DDS), phase-locked to the beam signal from a special high-sensitivity pick-up. The magnetic field is obtained from the so-called B-train. From these two values, the MRP is calculated. The precision depends on the frequency measurement and on the accuracy of the value for the magnetic field. Furthermore, exact knowledge of the transition energy is essential. This paper describes the hardware and software developed for the MRP system, and discusses the issue of calibration, with a proton beam, of the B measurement.

  10. Developmental Status of Beam Position and Phase Monitor for PEFP Proton Linac

    Science.gov (United States)

    Park, Sungju; Park, Jangho; Yu, Inha; Kim, Dotae; Hwang, Jung-Yun; Nam, Sanghoon

    2004-11-01

    The PEFP (Proton Engineering Frontier Project) at the KAERI (Korea Atomic Energy Research Institute) is building a high-power proton linear accelerator aiming to generate 100-MeV proton beams with 20-mA peak current. (Pulse width and max. repetition rate of 1 ms and 120 Hz respectively.) We have developed the Beam Position and Phase Monitor (BPPM) for the machine that features the button-type PU, the full-analog processing electronics, and the EPICS-based control system. The beam responses of the button-type PU have been obtained using the MAGIC (Particle-In-Cell) code. The processing electronics has been developed in collaboration with Bergoz Instrumentation. In this article, we report the present status of the system developments except the control system.

  11. Two transparent optical sensors for the positioning of detectors using a reference laser beam

    International Nuclear Information System (INIS)

    We have developed two different optical systems in order to position detectors with respect to a reference laser beam. The first system, a telescope, permits the absolute positioning of an element with respect to a reference laser beam. The resolution is of the order of 10 μm in translation and 50 μrad in rotation. It is highly transparent (-90%) permitting several elements to be aligned. A calibration procedure has also been studied and is currently being tested in order to obtain an absolute alignment information. The second system is a highly transparent (95%) two dimensional position sensor which allows the accurate positioning (below 20 μm) of several (up to ten) elements to which each sensor is attached, transversally to a laser beam used as a reference straight line. The present useful area of the first sensor is 20 x 20 mm2 and is 15 x 15 mm2 for the second. In both case it can be further increased to meet the experiment's requirement. (authors)

  12. Sub-micron resolution rf cavity beam position monitor system at the SACLA XFEL facility

    Energy Technology Data Exchange (ETDEWEB)

    Maesaka, H., E-mail: maesaka@spring8.or.jp [RIKEN SPring-8 Center, Sayo, Hyogo (Japan); Ego, H. [RIKEN SPring-8 Center, Sayo, Hyogo (Japan); Inoue, S. [SPring-8 Service Co. Ltd., Tatsuno, Hyogo (Japan); Matsubara, S. [Japan Synchrotron Radiation Research Institute, Sayo, Hyogo (Japan); Ohshima, T.; Shintake, T.; Otake, Y. [RIKEN SPring-8 Center, Sayo, Hyogo (Japan)

    2012-12-22

    We have developed and constructed a C-band (4.760 GHz) rf cavity beam position monitor (RF-BPM) system for the XFEL facility at SPring-8, SACLA. The demanded position resolution of the RF-BPM is less than 1{mu}m, because an electron beam and x-rays must be overlapped within 4{mu}m precision in the undulator section for sufficient FEL interaction between the electrons and x-rays. In total, 57 RF-BPMs, including IQ demodulators and high-speed waveform digitizers for signal processing, were produced and installed into SACLA. We evaluated the position resolutions of 20 RF-BPMs in the undulator section by using a 7 GeV electron beam having a 0.1 nC bunch charge. The position resolution was measured to be less than 0.6{mu}m, which was sufficient for the XFEL lasing in the wavelength region of 0.1 nm, or shorter.

  13. Systematic comparison of position and time dependent macroparticle simulations in beam dynamics studies

    International Nuclear Information System (INIS)

    Macroparticle simulation plays an important role in modern accelerator design and operation. Most linear rf accelerators have been designed based on macroparticle simulations using longitudinal position as the independent variable. In this paper, we have done a systematic comparison between using longitudinal position as the independent variable and using time as the independent variable in macroparticle simulations. We have found that, for an rms-matched beam, the maximum relative moment difference for second, fourth moments and beam maximum amplitudes between these two types of simulations is 0.25 percent in a 10 m reference transport system with physical parameters similar to the Spallation Neutron Source linac design. The maximum z-to-t transform error in the space-charge force calculation of the position dependent simulation is about 0.1 percent in such a system. This might cause a several percent error in a complete simulation of a linac with a length of hundreds of meters. Furthermore, the error may be several times larger in simulations of mismatched beams. However, if such errors are acceptable to the linac designer, then one is justified in using position dependent macroparticle simulations in this type of linac design application

  14. Smart x-ray beam position monitor system for the Advanced Photon Source

    International Nuclear Information System (INIS)

    In third-generation synchrotron radiation sources, such as the Advanced Photon Source (APS), the sensitivity and reliability requirements for the x-ray beam position monitors (XBPMs) are much higher than for earlier systems. Noise and contamination signals caused by radiation emitted from the bending magnet become a major problem. The regular XBPM calibration process can only provide signal correction for one set of conditions for the insertion devices (ID). During normal operation, parameters affecting the ID-emitted beam, such as the gap of the ID magnets and the beam current, are the variables. A new smart x-ray beam position monitor system (SBPM) has been conceived and designed for the APS. It has a built in self-learning structure with EEPROM memory that is large enough to open-quote open-quote remember close-quote close-quote a complete set of calibration data covering all the possible operating conditions. During the self-learning mode, the monitor system initializes a series of automatic scan motions with information for different ID setups and records them into the database array. During normal operation, the SBPM corrects the normalized output according to the ID setup information and the calibration database. So that, with this novel system, the SBPM is always calibrating itself with the changing ID set up conditions. copyright 1996 American Institute of Physics

  15. Calibration of beam position indicators for insertion devices of Indus-2

    International Nuclear Information System (INIS)

    Two insertion devices (undulators named U-l and U-2) have been recently installed in Indus-2 synchrotron radiation source, a 2.5 GeV third generation electron storage ring at Raja Ramanna Centre for Advanced Technology, Indore. Four ultra-high vacuum compatible beam position indicators (IDBPIs) for insertion devices have been designed and developed. These IDBPIs have been installed in the long straight sections LS-2 and LS-3 of Indus-2 ring at the upstream side and downstream side of undulators for the precise monitoring of electron beam position. The IDBPIs have been calibrated on a calibration bench setup before their installation in Indus-2 ring. The calibration procedure along with the calibration results has been described in this paper

  16. Model-independent analysis of the Fermilab Tevatron turn-by-turn beam position monitor measurements

    Energy Technology Data Exchange (ETDEWEB)

    Petrenko, A.V.; /Novosibirsk, IYF; Valishev, A.A.; Lebedev, V.A.; /Fermilab

    2011-09-01

    Coherent transverse beam oscillations in the Tevatron were analyzed with the model-independent analysis (MIA) technique. This allowed one to obtain the model-independent values of coupled betatron amplitudes, phase advances, and dispersion function around the ring from a single dipole kick measurement. In order to solve the MIA mode mixing problem which limits the accuracy of determination of the optical functions, we have developed a new technique of rotational MIA mode untangling. The basic idea is to treat each beam position monitor (BPM) as two BPMs separated in a ring by exactly one turn. This leads to a simple criterion of MIA mode separation: the betatron phase advance between any BPM and its counterpart shifted by one turn should be equal to the betatron tune and therefore should not depend on the BPM position in the ring. Furthermore, we describe a MIA-based technique to locate vibrating magnets in a storage ring.

  17. RF measurements of a C-band cavity beam position monitor

    Institute of Scientific and Technical Information of China (English)

    CHU Jian-Hua; TONG De-Chun; ZHAO Zhen-Tang

    2008-01-01

    RF cold test of a novel C-band cavity beam position monitor (PBM) to be used in the SDUVFEL Test Facility is described.The test results are presented and some characteristics discussed.The main parameters obtained are in reasonable agreement with the analytical estimations.Effective suppression of the common mode has been demonstrated.The position sensitivity over the test region of±0.5 mm is about -21.58 dB/10 μm for the TM110 mode and is linear in the central region of the BPM cavity.

  18. The Study of New Signal Processing Technique in Photon Beam Position Monitors

    CERN Document Server

    Lin, Shunfu; Lu, Ping; Sun Bao Gen; Wang, Jigang

    2005-01-01

    A log-ratio signal processing technique in photon beam position monitors (PBPM) was presented in this paper. The main performances (e.g. sensitivity, position offset and linearity range) of split PBPM and a pair of wires PBPM were analyzed , and the result of the measurement fit well with the theory. An inexpensive logarithmic amplifier chip which can measure photon currents from 0.1nA to 3.5mA was used in electronic circuits. The logarithmic ratio of the signal amplitudes from the PBPM provides a real-time analog signal that has wider linearity range and higher bandwidth than signal processing technique.

  19. Beam deflector and position sensor using electrowetting and mechanical wetting of sandwiched droplets

    Science.gov (United States)

    Shahzad, Amir; Song, Jang-Kun

    2016-09-01

    Electrowetting (EW) offers a facile manipulation of a liquid droplet on a surface, and several different systems have been suggested to utilize EW on various applications. In this letter, the manipulation of an electrolyte droplet with a floating movable substrate was investigated on a solid substrate. Two types of approaches were made; firstly, we controlled the vertical position of a floating substrate using EW property of droplets. The tilting angle of a floating substrate can be precisely controlled along two orthogonal directions independently, which can be used to devise a beam deflector. In the other case, mechanical wetting of droplets via external pressure was used to detect the position of a floating substrate; this position sensor has at least four orders of magnitude higher sensitivity than the conventional position sensor based on capacitance.

  20. Novel probe for determining the size and position of a relativistic electron beam

    International Nuclear Information System (INIS)

    In order to determine the size and position of a relativistic electron beam inside the wiggler magnetic field of a Free Electron Laser (FEL), we have developed a new probe which intercepts the electron beam on a high Z target and monitors the resulting bremsstrahlung radiation. The probe is designed to move along the entire three meters of the wiggler. This FEL is designed to operate in the microwave region (2 to 8 mm) and the interaction region is an oversized waveguide with a cross section 3 cm x 9.8 cm. The axial probe moves inside this waveguide. The probe stops the electron beam on a Tantalum target and the resulting x-rays are scattered in the forward direction. A scintillator behind the beam stop reacts to the x-rays and emits visible light in the region where the x-rays strike. An array of fiber optics behind the scintillator transmits the visible light to a Reticon camera system which images the visible pattern from the scintillator. Processing the optical image is done by digitizing and storing the image and/or recording the image on video tape. Resolution and performance of this probe will be discussed

  1. Operational Experience with Beam Alignment and Monitoring Using Non-Destructive Beam Position Monitors in the Cyclotron Beamlines at iThemba LABS

    CERN Document Server

    Conradie, J L; Delsink, J L G; Fourie, D T; Kormany, Z; Mansfield, P T; Rohwer, P F; Sakildien, M

    2005-01-01

    At iThemba LABS proton beams, accelerated in a K=200 separated-sector cyclotron with a K=8 solid-pole injector cyclotron, are utilized for the production of radioisotopes and particle radiotherapy. Beams of heavy ions and polarized protons, pre-accelerated in a second injector cyclotron, are available for nuclear physics research. Beam position monitors have been developed for non-destructive alignment and continuous display of the beam position in the beam lines for the more intense beams used for therapy and the production of radioisotopes in cooperation* with Forschungszentrum Jülich. The monitors consist of four-section strip lines. Narrow-band super-heterodyne RF electronic equipment with automatic frequency and gain control measures the signals at the selected harmonic. A control module sequentially processes the signals and delivers calculated horizontal and vertical beam position data via a serial network to the computer control system. Eleven monitors have been installed in the transfer beam line be...

  2. New X-ray beam position monitors with submicron resolution utilizing imaging of scattered X-rays at CHESS

    Energy Technology Data Exchange (ETDEWEB)

    Revesz, Peter, E-mail: pr20@cornell.edu [Cornell University, Cornell High Energy Synchrotron Source, Ithaca 14850, NY (United States); Temnykh, Alexander B. [Cornell University, Laboratory for Elem-Particle Physics, Ithaca 14850, NY (United States); Pauling, Alan K. [Cornell University, Cornell High Energy Synchrotron Source, Ithaca 14850, NY (United States)

    2011-09-01

    At CHESS' A, F and G wiggler beam lines three new video beam position monitors (VBPMs) have been commissioned. These new VBPMs utilize X-rays scattered from the graphite filter (A and F line) or from a beryllium window (G-line) as the white wiggler beam passes through them. As the X-rays scatter in all directions from the scattering medium, a slit camera creates an image of the beam's footprint on a fluorescent screen. This image is then viewed by a CCD camera and analyzed using a computer program to calculate the intensity centroid, the beam profile and integrated intensity. These data are delivered to the CHESS signal archiving system for storage and display. The new systems employ digital cameras. These cameras are free of the noise inherent to the analog systems with long video signal connections. As a result, the beam position data delivered by the new systems are more reliable and accurate as shown by beam position traces using different beam position monitors on the same beam line.

  3. New X-ray beam position monitors with submicron resolution utilizing imaging of scattered X-rays at CHESS

    Science.gov (United States)

    Revesz, Peter; Temnykh, Alexander B.; Pauling, Alan K.

    2011-09-01

    At CHESS' A, F and G wiggler beam lines three new video beam position monitors (VBPMs) have been commissioned. These new VBPMs utilize X-rays scattered from the graphite filter (A and F line) or from a beryllium window (G-line) as the white wiggler beam passes through them. As the X-rays scatter in all directions from the scattering medium, a slit camera creates an image of the beam's footprint on a fluorescent screen. This image is then viewed by a CCD camera and analyzed using a computer program to calculate the intensity centroid, the beam profile and integrated intensity. These data are delivered to the CHESS signal archiving system for storage and display. The new systems employ digital cameras. These cameras are free of the noise inherent to the analog systems with long video signal connections. As a result, the beam position data delivered by the new systems are more reliable and accurate as shown by beam position traces using different beam position monitors on the same beam line.

  4. SWG-designed MMI waveguides for dual and multi-beam splitting, beam position-shifting, and focusing purposes

    Science.gov (United States)

    Abdolahi, Z.; Jiang, H.; Kaminska, B.

    2016-03-01

    In this research, subwavelength grating (SWG) nanostructures with different periodic configurations are designed on a slab dielectric waveguide and theoretically studied for creating beam splitting, position-shifting, and focusing effects, using Comsol Multiphysics as the simulation tool. Su8 with a refractive index (n) of 1.585 is considered as the core material for the dielectric waveguide, which has a lateral and longitudinal dimension of 3 and 6 um, respectively. Uniform and nonuniform rows and columns of nanoholes with diameters of 90 nm are considered as the diffractive design elements. We took advantage of the multimode interference (MMI) phenomenon caused by periodic arrays of nanoholes as SWG structures, which are engineered to induce the desired effects. The power transmission efficiencies of the SWG-designed MMI waveguides are calculated in the wavelength range of 500-1200 nm. The efficiencies are high for the major part of the studied spectrum and reach a maximum of ~97% at 1200 nm for some designs. Also, the refractive index contrasts between the effective index (neff) and the ideal parabolic model (npar) are shown for the conventional MMI SU8 waveguide within a wavelength range of 700-1000 nm. It can be clearly seen that the contrast is minimum for λ = 700nm, and increases with wavelength, showing the multimode interference effect is optimum at 700 nm and deteriorates as the wavelength increases. Modal phase error (MPE) estimated for m=5 and different wavelengths revealed that the MMI device can have a fairly high performance within the whole studied wavelength range for a maximum mode number of 3. Additionally, the field intensity distributions calculated for the design with the beam splitting effect for different wavelengths reflected that the effect has a broadband characteristic.

  5. Calibration of a Non-Linear Beam Position Monitor Electronics by Switching Electrode Signals

    CERN Document Server

    Gasior, M

    2013-01-01

    Button electrode signals from beam position monitors embedded into new LHC collimators will be individually processed with front-end electronics based on compensated diode detectors and digitized with 24-bit audio-range ADCs. This scheme allows sub-micrometre beam orbit resolution to be achieved with simple hardware and no external timing. As the diode detectors only operate in a linear regime with large amplitude signals, offset errors of the electronics cannot be calibrated in the classical way with no input. This paper describes the algorithms developed to calibrate the offset and gain asymmetry of these nonlinear electronic channels. Presented algorithm application examples are based on measurements performed with prototype diode orbit systems installed on the CERN SPS and LHC machines.

  6. Active Position Control of a Flexible Smart Beam Using Internal Model Control

    Science.gov (United States)

    LEE, Y.-S.; ELLIOTT, S. J.

    2001-05-01

    The problem of controlling the position at the tip of a flexible cantilever beam to follow a command signal is considered, by using a pair of piezoelectric actuators at the clamped end. The beam is lightly damped and so the natural transient response is rather long, and also since the sensor and actuator are not collocated, the plant response is non-minimum phase. Two control strategies were investigated. The first involved conventional PID control in which the feedback gains were adjusted to give the fastest closed-loop response to a step input. The second control strategy was based on an internal model control (IMC) architecture. The control filter in the IMC controller was a digital FIR device designed to minimize the expectation of the mean square tracking error. In practice, such smart beams could be exposed to temperature fluctuations and changes in geometry. The effect of these variations on the stability was studied and it is shown that the need for robustness to such variations leads to a limitation in the performance of an IMC controller. The improvement in the stability robustness by incorporating control effort weighting into the cost function being minimized was investigated, as was the incorporation of modelling delay in the design of the IMC control filter. The IMC controller designed for the beam was found to have much reduced settling times to a step input compared with those of the PID controller while maintaining good robustness to changes in temperature. However, the extremely low damping of the experimental beam made it difficult to implement an accurate plant model in practice.

  7. Simulation of the interaction of positively charged beams and electron clouds

    International Nuclear Information System (INIS)

    The incoherent (head-tail) effect on the bunch due to the interaction with electron clouds (e-clouds) leads to a blow up of the transverse beam size in storage rings operating with positively charged beams. Even more the e-cloud effects are considered to be the main limiting factor for high current, high-brightness or high-luminosity operation of future machines. Therefore the simulation of e-cloud phenomena is a highly active field of research. The main focus in this work was set to a development of a tool for simulation of the interaction of relativistic bunches with non-relativistic parasitic charged particles. The result is the Particle-In-Cell Program MOEVE PIC Tracking which can track a 3D bunch under the influence of its own and external electromagnetic fields but first and foremost it simulates the interaction of relativistic positively charged bunches and initially static electrons. In MOEVE PIC Tracking the conducting beam pipe can be modeled with an arbitrary elliptical cross-section to achieve more accurate space charge field computations for both the bunch and the e-cloud. The simulation of the interaction between positron bunches and electron clouds in this work gave a detailed insight of the behavior of both particle species during and after the interaction. Further and ultimate goal of this work was a fast estimation of the beam stability under the influence of e-clouds in the storage ring. The standard approach to simulate the stability of a single bunch is to track the bunch particles through the linear optics of the machine by multiplying the 6D vector of each particle with the transformation matrices describing the lattice. Thereby the action of the e-cloud on the bunch is approximated by a pre-computed wake kick which is applied on one or more points in the lattice. Following the idea of K.Ohmi the wake kick was pre-computed as a two variable function of the bunch part exiting the e-cloud and the subsequent parts of a bunch which receive a

  8. A configurable electronics system for the ESS-Bilbao beam position monitors

    Energy Technology Data Exchange (ETDEWEB)

    Muguira, L., E-mail: lmuguira@essbilbao.org [ESS-Bilbao, Edificio Rectorado, Vivero de Empresas, 48940 Leioa (Bizkaia) (Spain); Belver, D. [ESS-Bilbao, Edificio Rectorado, Vivero de Empresas, 48940 Leioa (Bizkaia) (Spain); Etxebarria, V. [University of Basque Country (UPV/EHU), Department of Electricity and Electronics, Science and Technology Faculty, 48940 Leioa (Bizkaia) (Spain); Varnasseri, S.; Arredondo, I.; Campo, M. del; Echevarria, P.; Garmendia, N.; Feuchtwanger, J. [ESS-Bilbao, Edificio Rectorado, Vivero de Empresas, 48940 Leioa (Bizkaia) (Spain); Jugo, J.; Portilla, J. [University of Basque Country (UPV/EHU), Department of Electricity and Electronics, Science and Technology Faculty, 48940 Leioa (Bizkaia) (Spain)

    2013-09-01

    A versatile and configurable system has been developed in order to monitorize the beam position and to meet all the requirements of the future ESS-Bilbao Linac. At the same time the design has been conceived to be open and configurable so that it could eventually be used in different kinds of accelerators, independent of the charged particle, with minimal change. The design of the Beam Position Monitors (BPMs) system includes a test bench both for button-type pick-ups (PU) and striplines (SL), the electronic units and the control system. The electronic units consist of two main parts. The first part is an Analog Front-End (AFE) unit where the RF signals are filtered, conditioned and converted to base-band. The second part is a Digital Front-End (DFE) unit which is based on an FPGA board where the base-band signals are sampled in order to calculate the beam position, the amplitude and the phase. To manage the system a Multipurpose Controller (MC) developed at ESSB has been used. It includes the FPGA management, the EPICS integration and Archiver Instances. A description of the system and a comparison between the performance of both PU and SL BPM designs measured with this electronics system are fully described and discussed. -- Author-Highlights: • A versatile and configurable BPM system for the ESS-Bilbao Linac has been designed. • The design works for PU and SL detectors, both in continuous and pulsed wave modes. • Several tests at simulated beamlines at 352 MHz and 175 MHz have been performed. • The BPM system has been integrated in EPICS and Archiver.

  9. A configurable electronics system for the ESS-Bilbao beam position monitors

    International Nuclear Information System (INIS)

    A versatile and configurable system has been developed in order to monitorize the beam position and to meet all the requirements of the future ESS-Bilbao Linac. At the same time the design has been conceived to be open and configurable so that it could eventually be used in different kinds of accelerators, independent of the charged particle, with minimal change. The design of the Beam Position Monitors (BPMs) system includes a test bench both for button-type pick-ups (PU) and striplines (SL), the electronic units and the control system. The electronic units consist of two main parts. The first part is an Analog Front-End (AFE) unit where the RF signals are filtered, conditioned and converted to base-band. The second part is a Digital Front-End (DFE) unit which is based on an FPGA board where the base-band signals are sampled in order to calculate the beam position, the amplitude and the phase. To manage the system a Multipurpose Controller (MC) developed at ESSB has been used. It includes the FPGA management, the EPICS integration and Archiver Instances. A description of the system and a comparison between the performance of both PU and SL BPM designs measured with this electronics system are fully described and discussed. -- Author-Highlights: • A versatile and configurable BPM system for the ESS-Bilbao Linac has been designed. • The design works for PU and SL detectors, both in continuous and pulsed wave modes. • Several tests at simulated beamlines at 352 MHz and 175 MHz have been performed. • The BPM system has been integrated in EPICS and Archiver

  10. Experimental demonstration of interaction region beam waist position knob for luminosity leveling

    International Nuclear Information System (INIS)

    In this paper, we report the experimental implementation of the model-dependent control of the interaction region beam waist position (s* knob) at Relativistic Heavy Ion Collider (RHIC). The s* adjustment provides an alternative way of controlling the luminosity and is only known method to control the luminosity and reduce the pinch effect of the future eRHIC. In this paper, we will first demonstrate the effectiveness of the s* knob in luminosity controlling and its application in the future electron ion collider, eRHIC, followed by the detail experimental demonstration of such knob in RHIC.

  11. Polarizabilities of an annular cut and coupling impedances of button type beam position monitors

    Science.gov (United States)

    Kurennoy, Sergei S.

    The longitudinal and transverse coupling impedances of a small discontinuity on the accelerator chamber wall can be expressed in terms of the electric and magnetic polarizabilities of the discontinuity. The polarizabilities are geometrical factors and can be found by solving a static (electric or magnetic) problem. However, they are known in the explicit analytical form only for a few simple-shaped discontinuities, for example, for an elliptic hole in a thin wall. In the present paper the polarizabilities of a ring-shaped cut in the wall are obtained. The results are applied to calculate the coupling impedances of button-type beam position monitors.

  12. Polarizabilities of an annular cut and coupling impedances of button-type beam position monitors

    CERN Document Server

    Kurennoy, S S

    1995-01-01

    The longitudinal and transverse coupling impedances of a small discontinuity on the accelerator chamber wall can be expressed in terms of the electric and magnetic polarizabilities of the discontinuity. The polarizabilities are geometrical factors and can be found by solving a static (electric or magnetic) problem. However, they are known in the explicit analytical form only for a few simple-shaped discontinuities, for example, for an elliptic hole in a thin wall. In the present paper the polarizabilities of a ring-shaped cut in the wall are obtained. The results are applied to calculate the coupling impedances of button-type beam position monitors.

  13. Generation of energetic He atom beams by a pulsed positive corona discharge

    OpenAIRE

    Lo, Shui-Yin; Lobo, Julio D.; Blumberg, Seth; Dibble, Theodore S.; Zhang, Xu; Tsao, Chun-Cheng; Okumura, Mitchio

    1997-01-01

    Time-of-flight measurements were made of neutral helium atom beams extracted from a repetitive, pulsed, positive-point corona discharge. Two strong neutral peaks, one fast and one slow, were observed, accompanied by a prompt photon peak and a fast ion peak. All peaks were correlated with the pulsing of the discharge. The two types of atoms appear to be formed by different mechanisms at different stages of the corona discharge. The fast atoms had energies of 190 eV and were formed at the onset...

  14. Experimental demonstration of interaction region beam waist position knob for luminosity leveling

    Energy Technology Data Exchange (ETDEWEB)

    Hao, Yue [Brookhaven National Lab. (BNL), Upton, NY (United States); Bai, Mei [Inst. fuer Kernphysik, Juelich (Germany). Inst. for Advanced Simulation; Duan, Zhe [Inst. of High Energy Physics, Beijing (China); Luo, Yun [Brookhaven National Lab. (BNL), Upton, NY (United States); Marusic, Aljosa [Brookhaven National Lab. (BNL), Upton, NY (United States); Robert-Demolaize, Guillaume [Brookhaven National Lab. (BNL), Upton, NY (United States); Shen, Xiaozhe [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-05-03

    In this paper, we report the experimental implementation of the model-dependent control of the interaction region beam waist position (s* knob) at Relativistic Heavy Ion Collider (RHIC). The s* adjustment provides an alternative way of controlling the luminosity and is only known method to control the luminosity and reduce the pinch effect of the future eRHIC. In this paper, we will first demonstrate the effectiveness of the s* knob in luminosity controlling and its application in the future electron ion collider, eRHIC, followed by the detail experimental demonstration of such knob in RHIC.

  15. Influence of positive ions on oscillatory processes in an electron beam with virtual cathode

    Science.gov (United States)

    Filatov, R. A.; Kalinin, Yu. A.; Khramov, A. E.; Trubetskov, D. I.

    2006-10-01

    We numerically simulate the influence of positive ions on characteristics of the microwave oscillations in a nonrelativistic electron beam with the virtual cathode formed in a decelerating field (low-voltage vircator). A numerical scheme allowing for ionization of a residual gas by an electron flow is proposed. It is shown that the residual-gas ionization in the operating chamber of a low-voltage vircator leads to a forcing of the virtual cathode out of the transit gap and to a cutoff of microwave oscillations. The obtained numerical data are confirmed by an experimental study using a low-voltage vircator model.

  16. Evaluation of positioning errors of the patient using cone beam CT megavoltage; Evaluacion de errores de posicionamiento del paciente mediante Cone Beam CT de megavoltaje

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Ruiz-Zorrilla, J.; Fernandez Leton, J. P.; Zucca Aparicio, D.; Perez Moreno, J. M.; Minambres Moro, A.

    2013-07-01

    Image-guided radiation therapy allows you to assess and fix the positioning of the patient in the treatment unit, thus reducing the uncertainties due to the positioning of the patient. This work assesses errors systematic and errors of randomness from the corrections made to a series of patients of different diseases through a protocol off line of cone beam CT (CBCT) megavoltage. (Author)

  17. Free Electron Laser For The Siberian Centre For Photochemical Reseach Software And Capabilities Of Beam Position Measurement System

    CERN Document Server

    Dementyev, E N; Medvedko, A S; Oreshkov, A D; Serednyakov, S I; Shubin, E N; Vinokurov, N A

    2004-01-01

    The system for electron beam position measurement in microtron-recuperator, using the electrostatic pick-up electrodes is described. Option of simultaneous detection of accelerated and decelerated electron beams is considered. The software and its capability of integration to the Epics control system using Epics Channel Access protocol are discussed.

  18. Output beam energy measurement of a 100-MeV KOMAC drift tube linac by using a stripline beam position monitor

    Science.gov (United States)

    Kim, Han-Sung

    2015-10-01

    The 100-MeV proton linac at the KOMAC (Korea Multi-purpose Accelerator Complex) is composed of a 50-keV proton injector, a 3-MeV RFQ (radio-frequency quadrupole) and a 100-MeV DTL (drift tube linac). The proton beam is accelerated from 3 MeV to 100 MeV through 11 DTL tanks. The precise measurement of the proton-beam's energy at the output of each DTL tank is important for the longitudinal beam dynamics and can be performed by using a time-of-flight method with a BPM (beam position monitor), which is installed between each DTL tank. The details of the output beam energy measurement of the KOMAC DTL with stripline-type BPM and BPM signal processing, along with a comparison with the simulation results, will be presented in this paper.

  19. Determination of wafer center position during the transfer process by using the beam-breaking method

    International Nuclear Information System (INIS)

    A wafer on a robot blade may slip due to inertia sliding during the acceleration or deceleration process. This study presents the implementation and experimental verification of a novel real-time wafer positioning system to be used during the transfer process. A system-integration computer program involving a human–machine interface (HMI) was also developed, exhibiting the following functions: (a) moving direction judgment; (b) notch-passing judgment; (c) indicating the sensor by which the notch passes; and (d) computing the wafer center in real time. The position of the wafer center is calculated based on the time-sequence of the beam-breaking signals from two optical sensors, and the geometric relations among the sensing points of the robot blade and wafer. When using eight-inch wafers, the experimental results indicated the capabilities of the proposed positioning system under various conditions, including distinct parameters regarding the moving direction, wafer displacement and notch-passing sensors. The accuracy and precision (repeatability) of the measurement in various conditions were calculated and discussed. Furthermore, the experimental results demonstrate that, after combining the novel wafer positioning system and HMI program, the proposed method can be used to compute the position of the wafer center in real time in various conditions. (paper)

  20. Determination of wafer center position during the transfer process by using the beam-breaking method

    Science.gov (United States)

    Chen, Yi-Cheng; Wang, Zhi-Gen; Huang, Bo-Kai

    2014-09-01

    A wafer on a robot blade may slip due to inertia sliding during the acceleration or deceleration process. This study presents the implementation and experimental verification of a novel real-time wafer positioning system to be used during the transfer process. A system-integration computer program involving a human-machine interface (HMI) was also developed, exhibiting the following functions: (a) moving direction judgment; (b) notch-passing judgment; (c) indicating the sensor by which the notch passes; and (d) computing the wafer center in real time. The position of the wafer center is calculated based on the time-sequence of the beam-breaking signals from two optical sensors, and the geometric relations among the sensing points of the robot blade and wafer. When using eight-inch wafers, the experimental results indicated the capabilities of the proposed positioning system under various conditions, including distinct parameters regarding the moving direction, wafer displacement and notch-passing sensors. The accuracy and precision (repeatability) of the measurement in various conditions were calculated and discussed. Furthermore, the experimental results demonstrate that, after combining the novel wafer positioning system and HMI program, the proposed method can be used to compute the position of the wafer center in real time in various conditions.

  1. Beam size and position measurement based on logarithm processing algorithm in HLS II

    CERN Document Server

    Cheng, Chaocai; Yang, Yongliang; Zhou, Zeran; Lu, Ping; Wu, Fangfang; Wang, Jigang; Tang, Kai; Luo, Qing; Li, Hao; Zheng, Jiajun; Duan, Qingming

    2015-01-01

    A logarithm processing algorithm to measure beam transverse size and position is proposed and preliminary experimental results in Hefei Light Source II (HLS II) are given. The algorithm is based on only 4 successive channels of 16 anode channels of multianode photomultiplier tube (MAPMT) R5900U-00-L16 which has typical rise time of 0.6 ns and effective area of 0.8x16 mm for a single anode channel. In the paper, we firstly elaborate the simulation results of the algorithm with and without channel inconsistency. Then we calibrate the channel inconsistency and verify the algorithm using general current signal processor Libera Photon in low-speed scheme. Finally we get turn-by-turn beam size and position and calculate the vertical tune in high-speed scheme. The experimental results show that measured values fit well with simulation results after channel differences are calibrated and the fractional part of the tune in vertical direction is 0.3628 which is very close to the nominal value 0.3621.

  2. Performance of the beam position monitor for the Advanced Photon Source

    International Nuclear Information System (INIS)

    Performance measurement and analysis of the Advanced Photon Source (APS) beam position monitor (BPM) electronics are reported. The results indicate a BPM resolution of 0.16 μm·mA/√Hz in terms of the single-bunch current and BPM bandwidth. For the miniature insertion device (ID) BPM, the result was 0.1 μm·mA/√Hz. The improvement is due to the 3.6 times higher position sensitivity (in the vertical plane), which is partially canceled by the lower button signal by a factor of 2.3. The minimum single-bunch current required was roughly 0.03 mA. The long-term drift of the BPM electronics independent of the actual beam motion was measured at 2 μm/hr, which settled after approximately 1.5 hours. This drift can be attributed mainly to the temperature effect. Implications of the BPM resolution limit on the global and local orbit feedback systems for the APS storage ring will also be discussed

  3. Radiation Resistance testing of commercial components for the new SPS Beam Position Measurement System

    CERN Document Server

    Deplano, C; Bogey, T; Gonzalez, J L; Savioz, J J

    2013-01-01

    A new Front-End (FE) electronics is under development for the SPS Multi Orbit POsition System (MOPOS). To cover the large dynamic range of beam intensities (70 dB) to be measured in the SPS, the beam position monitor signals are processed using logarithmic amplifiers. They are then digitized locally and transmitted via optical fibers over long distances (up to 1 km) to VME acquisition boards located in surface buildings. The FE board is designed to be located in the SPS tunnel, where it must withstand radiation doses of up to 100 Gy per year. Analogue components, such as Logarithmic Amplifiers (LA), ADC-Drivers (ADC-D) and Voltage Regulators (VR), have been tested at PSI (Paul Scherrer Institute) for radiation hardness, while several families of bidirectional SFP, both single-fiber and double-fiber, have been tested at both PSI and CNRAD. This paper gives a description of the overall system architecture and presents the results of the radiation hardness tests in detail.

  4. Stabilization and Fine Positioning to the Nanometre Level of the CLIC Main Beam Quadrupoles

    CERN Document Server

    Artoos, K; Fernandez Carmona, P; Guinchard, M; Hauviller, C; Janssens, S; Kuzmin, A; Lackner, F; Leuxe, R; Slaathaug, A

    2010-01-01

    The CLIC main beam quadrupoles need to be stabilized to 1.5 nm integrated R.M.S. displacement at 1 Hz. The choice was made to apply active stabilization with piezoelectric actuators in a rigid support with flexural guides. The advantages of this choice are the robustness against external forces and the possibility to make fast incremental nanometre positioning of the magnet with the same actuators. The study and feasibility demonstration is made in several steps from a single degree of freedom system (s.d.o.f.) with a small mass, a s.d.o.f. with a large mass, leading to the demonstration including the smallest (type 1) and largest (type 4) CLIC main beam quadrupoles. The paper discusses the choices of the position and orientation of the actuators and the tailored rigidities of the flexural hinges in the multi degree of freedom system, and the corresponding MIMO control system. The compatibility with the magnet support and micrometre alignment system is essential. The status of the study and performed tests wi...

  5. Positioning of self-assembled InAs quantum dots by focused ion beam implantation

    International Nuclear Information System (INIS)

    Self-assembled quantum dots (QDs) are envisioned as building blocks for realization of novel nanoelectronic devices, for which the site-selective growth is highly desirable. This thesis presents a successful route toward selective positioning of self-assembled InAs QDs on patterned GaAs surface by combination of in situ focused ion beam (FIB) implantation and molecular beam epitaxy (MBE) technology. First, a buffer layer of GaAs was grown by MBE before a square array of holes with a pitch of 1-2 μm was fabricated by FIB implantation of Ga and In, ions respectively. Later, an in-situ annealing step followed by InAs deposition was performed. The InAs QDs were preferentially formed in the holes generated by FIB. The influence of ion dose, annealing parameters and InAs amount was investigated in this work. With optimized parameters, more than 50 % single dot occupancy per hole is achieved. Furthermore, the photoluminescence spectra from positioned QDs confirm their good optical quality. (orig.)

  6. Control of stopping position of radioactive ion beam in superfluid helium for laser spectroscopy experiments

    Energy Technology Data Exchange (ETDEWEB)

    Yang, X.F., E-mail: yangxf@ribf.riken.jp [School of Physics, Peking University, Chengfu Road, Haidian District, Beijing 100871 (China); RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Furukawa, T. [Dept. of Physics, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji, Tokyo 192-0397 (Japan); Wakui, T. [Cyclotron and Radioisotope Center Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8578 (Japan); Imamura, K. [Dept. of Physics, Meiji University, 1-1-1 Higashi-Mita, Tama-ku, Kawasaki, Kanagawa 214-8571 (Japan); Tetsuka, H. [Dept. of Physics, Tokyo Gakugei University, 4-1-1 Nukuikitamachi, Koganei, Tokyo 184-8501 (Japan); Fujita, T. [Dept. of Physics, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043 (Japan); Yamaguchi, Y. [Dept. of Physics, Meiji University, 1-1-1 Higashi-Mita, Tama-ku, Kawasaki, Kanagawa 214-8571 (Japan); Tsutsui, Y. [Dept. of Physics, Tokyo Gakugei University, 4-1-1 Nukuikitamachi, Koganei, Tokyo 184-8501 (Japan); Mitsuya, Y. [Dept. of Physics, Meiji University, 1-1-1 Higashi-Mita, Tama-ku, Kawasaki, Kanagawa 214-8571 (Japan); Ichikawa, Y. [Dept. of Physics, Tokyo Institute of Technology, 2-12-1 O-Okayama, Meguro, Tokyo152-8551 (Japan); Ishibashi, Y. [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Dept. of Physics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8571 (Japan); Yoshida, N.; Shirai, H. [Dept. of Physics, Tokyo Institute of Technology, 2-12-1 O-Okayama, Meguro, Tokyo152-8551 (Japan); Ebara, Y.; Hayasaka, M. [Dept. of Physics, Tokyo Gakugei University, 4-1-1 Nukuikitamachi, Koganei, Tokyo 184-8501 (Japan); Arai, S.; Muramoto, S. [Dept. of Physics, Meiji University, 1-1-1 Higashi-Mita, Tama-ku, Kawasaki, Kanagawa 214-8571 (Japan); Hatakeyama, A. [Dept. of Applied Physics, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588 (Japan); Wada, M.; Sonoda, T. [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); and others

    2013-12-15

    In order to investigate the structure of exotic nuclei with extremely low yields by measuring nuclear spins and moments, a new laser spectroscopy technique – “OROCHI” (Optical Radioisotopes Observation in Condensed Helium as Ion-catcher) has been proposed in recent years. The feasibility of this technique has been demonstrated by means of a considerable amount of offline and online studies of various atoms in superfluid helium. For in-situ laser spectroscopy of atoms in He II, trapping atoms in the observation region of laser is a key step. Therefore, a method which enables us to trap accelerated atoms at a precise position in He II is highly needed for performing experiment. In this work, a technique making use of a degrader, two plastic scintillators and a photon detection system is established for checking the stopping position of beam based on the LISE++ calculation. The method has been tested and verified by on-line experiments with the {sup 84,85,87}Rb beam. Details of the experimental setup, working procedure and testing results of this method are presented.

  7. Summary of LHC MD 398: Verification of the dependence of the BCTF measurements on beam position and bunch length

    CERN Document Server

    Krupa, Michal; Gasior, Marek; Lefevre, Thibaut; Soby, Lars; CERN. Geneva. ATS Department

    2015-01-01

    The main aim of the MD was to study the dependency of bunch-by-bunch intensity measurements to beam position and bunch length variations. Large beam position offsets in IR4 and varying bunch length were introduced to compare the performance of the presently installed Fast Beam Current Transformers with the new Integrating Current Transformer and the new Wall Current Transformer. This note explains all the procedures of the LHC MD 398, which took place on 20/07/2015, and presents the obtained results.

  8. Optimization of Focal Position of Ultrasonic Beam in Measurement of Small Change in Arterial Wall Thickness

    Science.gov (United States)

    Watanabe, Masaru; Kanai, Hiroshi

    2001-05-01

    We have previously developed a method for measurement of a small change in thickness of the arterial wall during a single cardiac cycle [H. Kanai, M. Sato, Y. Koiwa and N. Chubachi: IEEE Trans. UFFC 43 (1996) 791]. The resultant change in thickness is shown to be useful for the in vivo assessment of the regional elasticity of the arterial wall. Although the accuracy of the measurement of the change in thickness is found to be within 1 μm, it is affected by the interference of ultrasonic pulses. In this study, we simulate the propagation of ultrasonic pulses transmitted and received by a linear probe. In the simulation experiments, the ultrasonic pulses generated by a computer are reflected by a tube, which has a small change in wall thickness of 10 μm. The optimum focal position of the ultrasonic beam is determined by evaluating the root-mean-square (rms) error in the measured change in thickness.

  9. Design and Fabrication of the Beam Position Monitor for the PEFP Linac

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Hyeokjung; Kim, Hansung; Seol, Kyungtae; Ryu, Jinyeong; Jang, Jiho; Cho, Yongsub [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-08-15

    The beam position monitor (BPM) is an essential component for the PEFP 100-MeV linac's commissioning. A prototype stripline-type linac BPM was designed for this purpose. The electrode aperture is 20 mm in diameter, and the electrode is 25 mm long, so it can be installed between Drift Tube Linac (DTL)101 and DTL102, which is the shortest distance. One end of the electrode is connected to the Sub Miniature Type A (SMA) feed through for signal measurement, and the other end is terminated as a short. The signal amplitude of the fundamental component was calculated and compared with that of the second harmonic component. The designed BPM was fabricated and a low-power RF test was conducted. In this paper, the design, fabrication and low power test of the BPM for the PEFP linac are presented.

  10. Study of the new CSAR62 positive tone electron-beam resist at 40 keV electron energy

    Science.gov (United States)

    Andok, R.; Bencurova, A.; Vutova, K.; Koleva, E.; Nemec, P.; Hrkut, P.; Kostic, I.; Mladenov, G.

    2016-03-01

    One of the few "top-down" methods for nano-device fabrication is the electron-beam lithography, which allows flexible patterning of various structures with a nanoscale resolution down to less than 10 nm. Thinner, more etching durable, and more sensitive e-beam resists are required for the better control, linearity, and uniformity of critical dimensions of structures for nano-device fabrication. Within the last decade, researchers have made significant efforts to improve the resolution of the nanoscale e-beam lithography. The resist material properties are an important factor governing the resolution. Only the e-beam resist ZEP 520 of the Japanese manufacturer ZEON is characterized by relatively good properties and thus meets most users' expectations. This paper deals with the investigation and simulation of the characteristics of the new less-expensive AR-P 6200 (CSAR 62) positive e-beam resist (available since May 2013, manufactured by Allresist GmbH company).

  11. Latest Performance Results from the FONT5 Intra-train Beam Position and Angle Feedback System at ATF2

    CERN Document Server

    Christian, G B; Bett, D R; Blaskovic Kraljevic, N; Burrows, P N; Davis, M R; Gerbershagen, A; Perry, C; Constance, B; Resta-Lopez, J

    2012-01-01

    A prototype Interaction Point beam-based feedback system for future electron-positron colliders, such as the International Linear Collider, has been designed and tested on the extraction line of the KEK Accelerator Test Facility (ATF). The FONT5 intra-train feedback system aims to stabilize the beam orbit by correcting both the position and angle jitter in the vertical plane on bunch-tobunch time scales, providing micron-level stability at the entrance to the ATF2 final-focus system. The system comprises three stripline beam position monitors (BPMs) and two stripline kickers, custom low-latency analogue front-end BPM processors, a custom FPGA-based digital processing board with fast ADCs, and custom kickerdrive amplifiers. The latest results from beam tests at ATF2 will be presented, including the system latency and correction performance.

  12. Real-time detection of focal position of workpiece surface during laser processing using diffractive beam samplers

    Science.gov (United States)

    Cao, Binh Xuan; Hoang, PhuongLe; Ahn, Sanghoon; Kim, Jeng-o.; Sohn, Hyonkee; Noh, Jiwhan

    2016-11-01

    The real-time fabrication of microgrooves on a curved surface using a laser beam, without preprogramming their shapes into the machining instructions, is a major challenge in laser processing owing to limitations associated with the real-time detection of the focal position. A new approach using a sampled fraction of the beam from a diffractive beam sampler (DBS) is therefore presented in order to overcome this limitation. By considering the sampled fraction of the beam an analysis of the results allows for precise positioning of the specimen for focal-point identification. This allows for the determination of the focus for a broad variety of laser types and laser powers, thereby providing stringent focusing conditions with high numerical apertures. This approach is easy to implement, inexpensive, independent of the roughness or granularity of the workpieces, and more importantly does not require auxiliary lasers and displacement sensors for real-time measurement during the fabrication process.

  13. Scanning wire beam position monitor for alignment of a high brightness inverse-Compton x-ray source

    CERN Document Server

    Hadmack, Michael R

    2013-01-01

    The Free-Electron Laser Laboratory at the University of Hawai`i has constructed and tested a scanning wire beam position monitor to aid the alignment and optimization of a high spectral brightness inverse-Compton scattering x-ray source. X-rays are produced by colliding the 40 MeV electron beam from a pulsed S-band linac with infrared laser pulses from a mode-locked free-electron laser driven by the same electron beam. The electron and laser beams are focused to 60 {\\mu}m diameters at the interaction point to achieve high scattering efficiency. This wire-scanner allows for high resolution measurements of the size and position of both the laser and electron beams at the interaction point to verify spatial coincidence. Time resolved measurements of secondary emission current allow us to monitor the transverse spatial evolution of the e-beam throughout the duration of a 4 {\\mu}s macro-pulse while the laser is simultaneously profiled by pyrometer measurement of the occulted infrared beam. Using this apparatus we ...

  14. A novel diamond-based beam position monitoring system for the High Radiation to Materials facility at CERN SPS

    CERN Document Server

    AUTHOR|(CDS)2092886; Höglund, Carina

    The High Radiation to Materials facility employs a high intensity pulsed beam imposing several challenges on the beam position monitors. Diamond has been shown to be a resilient material with its radiation hardness and mechanical strength, while it is also simple due to its wide bandgap removing the need for doping. A new type of diamond based beam position monitor has been constructed, which includes a hole in the center of the diamond where the majority of the beam is intended to pass through. This increases the longevity of the detectors as well as allowing them to be used for high intensity beams. The purpose of this thesis is to evaluate the performance of the detectors in the High Radiation to Materials facility for various beam parameters, involving differences in position, size, bunch intensity and bunch number. A prestudy consisting of calibration of the detectors using single incident particles is also presented. The detectors are shown to work as intended after a recalibration of the algorithm, alb...

  15. Beam test of a one-dimensional position sensitive chamber on synchrotron radiation

    CERN Document Server

    Mei, Liu; Hui-Rong, Qi; Bao-An, Zhuang; Jian, Zhang; Rong-Guang, Liu; Qi-Ming, Zhu; Qun, Ouyang; Yuan-Bo, Chen; Xiao-Shan, Jiang; Ya-Jie, Wang; Peng, Liu; Guang-Cai, Chang

    2013-01-01

    One-dimensional single-wire chamber was developed to provide high position resolution for powder diffraction experiments with synchrotron radiation. A diffraction test using the sample of SiO2 has been accomplished at 1W2B laboratory of Beijing Synchrotron Radiation Source. The data of beam test were analyzed and some diffraction angles were obtained. The experimental results were in good agreement with standard data from ICDD powder diffraction file. The precision of diffraction angles was 1% to 4.7%. Most of relative errors between measured values of diffraction angles and existing data were less than 1%. As for the detector, the best position resolution in the test was 138 um (sigma value) with an X-ray tube. Finally, discussions of the results were given. The major factor that affected the precision of measurement was deviation from the flat structure of detector. The effect was analyzed and it came to a conclusion that it would be the optimal measurement scheme when the distance between the powder sample...

  16. Implementation of electron beam position measurement algorithm and embedded web server using MCS-51 microcontroller for Booster Synchrotron

    International Nuclear Information System (INIS)

    The Booster Synchrotron at RRCAT caters as Injector Machine for Indus-1 and Indus-2 with the repetition rate of 1Hz. In Booster Synchrotron, energy of electron bunches are increased from 20 MeV to 450 MeV (in ∼ 280 ms) and 550 MeV (in ∼ 340 ms ) for Indus-1 and Indus-2 respectively. An algorithm for microcontroller based beam position measurement system has been developed for the Booster Synchrotron to measure the fast changes in the beam position of electron bunches during energy ramping. In this paper, software implementation in microcontroller and its optimization to achieve beam position update rate of 1 kHz is discussed. (author)

  17. Influence of standing positions and beam projections on effective dose and eye lens dose of anaesthetists in interventional procedures

    International Nuclear Information System (INIS)

    More and more anaesthetists are getting involved in interventional radiology procedures and so it is important to know the radiation dose and to optimise protection for anaesthetists. In this study, based on Monte Carlo simulations and field measurements, both the whole-body doses and eye lens dose of anaesthetists were studied. The results showed that the radiation exposure to anaesthetists not only depends on their workload, but also largely varies with their standing positions and beam projections during interventional procedures. The simulation results showed that the effective dose to anaesthetists may vary with their standing positions and beam projections to more than a factor of 10, and the eye lens dose may vary with the standing positions and beam projections to more than a factor of 200. In general, a close position to the bed and the left lateral (LLAT) beam projection will bring a high exposure to anaesthetists. Good correlations between the eye lens dose and the doses at the neck, chest and waist over the apron were observed from the field measurements. The results indicate that adequate arrangements of anaesthesia device or other monitoring equipment in the fluoroscopy rooms are useful measures to reduce the radiation exposure to anaesthetists, and anaesthetists should be aware that they will receive the highest doses under left lateral beam projection. (authors)

  18. Generation of energetic He atom beams by a pulsed positive corona discharge

    International Nuclear Information System (INIS)

    Time-of-flight measurements were made of neutral helium atom beams extracted from a repetitive, pulsed, positive-point corona discharge. Two strong neutral peaks, one fast and one slow, were observed, accompanied by a prompt photon peak and a fast ion peak. All peaks were correlated with the pulsing of the discharge. The two types of atoms appear to be formed by different mechanisms at different stages of the corona discharge. The fast atoms had energies of 190 eV and were formed at the onset of the pulsing, approximately 0.7 μs before the maximum of the photon peak. The slow peak, composed of electronically metastable He atoms, originated 30 50 μs after the photon pulse, and possessed a nearly thermal velocity distribution. The velocity distribution was typical of an undisturbed supersonic expansion with a stagnation temperature of 131 K and a speed ratio of 3.6. Peak intensities and velocities were measured as a function of source voltage, stagnation pressure, and skimmer voltage. copyright 1997 American Institute of Physics

  19. Formation of ultra slow position beam and upgrading of material evaluation using it

    Energy Technology Data Exchange (ETDEWEB)

    Mikado, Tomohisa; Suzuki, Ryoichi; Odaira, Toshiyuki; Ohgaki, Hideaki; Yamada, Kawakatsu; Yamazaki, Tetsuo; Kobayashi, Yoshinori; Hirata, Koichi [Electrotechnical Lab., Tsukuba, Ibaraki (Japan)

    2000-02-01

    The Electrotechnical Laboratory has carried out development on a technique to form and control high intensity and slow positron beam by using high energy electron beam of electron accelerator, success in generation of ultra short pulse beam of incident energy variable positron with the highest intensity in the world, development on testing techniques of positron life, spectroscopic flight time of positron annihilation excited Auger electron and so on, and their applications. The 1998 fiscal year was the last fiscal year of this researching project, and together with conducting reform of forming method of high intensity positron beam, energy analysis of ultra slow positron beam and upgrading of incident energy variable positron lifetime testing the testing technique of the positron annihilation excited Auger electron spectroscopy and positron lifetime developed by this study was applied to various samples and effectiveness of analysis and evaluation methods using the ultra slow positron beam was investigated. As a result, it was succeeded in to make high intensity of 1 eV plus/minus 0.5 eV in energy And, on the positron annihilation excited Auger electron spectroscopy, at lifetime measurement of about 40 eV short pulse beam and incident energy variable positron beam, 0.2 to 0.3 keV short pulse positron beam could be formed to realize a material evaluation method with high counting rate, low background and high resolution. (G.K.)

  20. Formation of ultra slow position beam and upgrading of material evaluation using it

    International Nuclear Information System (INIS)

    The Electrotechnical Laboratory has carried out development on a technique to form and control high intensity and slow positron beam by using high energy electron beam of electron accelerator, success in generation of ultra short pulse beam of incident energy variable positron with the highest intensity in the world, development on testing techniques of positron life, spectroscopic flight time of positron annihilation excited Auger electron and so on, and their applications. The 1998 fiscal year was the last fiscal year of this researching project, and together with conducting reform of forming method of high intensity positron beam, energy analysis of ultra slow positron beam and upgrading of incident energy variable positron lifetime testing the testing technique of the positron annihilation excited Auger electron spectroscopy and positron lifetime developed by this study was applied to various samples and effectiveness of analysis and evaluation methods using the ultra slow positron beam was investigated. As a result, it was succeeded in to make high intensity of 1 eV plus/minus 0.5 eV in energy And, on the positron annihilation excited Auger electron spectroscopy, at lifetime measurement of about 40 eV short pulse beam and incident energy variable positron beam, 0.2 to 0.3 keV short pulse positron beam could be formed to realize a material evaluation method with high counting rate, low background and high resolution. (G.K.)

  1. Error analysis of linear optics measurements via turn-by-turn beam position data in circular accelerators

    CERN Document Server

    Franchi, Andrea

    2016-01-01

    Many advanced techniques have been developed, tested and implemented in the last decades in almost all circular accelerators across the world to measure the linear optics. However, the greater availability and accuracy of beam diagnostics and the ever better correction of linear magnetic lattice imperfections (beta beating at 1% level and coupling at 0.1%) are reaching what seems to be the intrinsic accuracy and precision of different measurement techniques. This paper aims to highlight and quantify, when possible, the limitations of one standard method, the harmonic analysis of turn-by-turn beam position data. To this end, new analytic formulas for the evaluation of lattice parameters modified by focusing errors are derived. The unexpected conclusion of this study is that for the ESRF storage ring (and possibly for any third generation light source operating at ultra-low coupling and with similar diagnostics), measurement and correction of linear optics via orbit beam position data are to be preferred to the...

  2. Development of a High Dynamic Range Beam Position Measurement system using Logarithmic Amplifiers for the SPS at CERN

    CERN Document Server

    Gonzalez, J L; Deplano, C; Savioz, J J

    2013-01-01

    A new Front-End electronics, based on Logarithmic Amplifiers, is currently being developed for the CERN SPS Multi Orbit POsition System (MOPOS). The aim is to resolve the multi-batch structure of the beams and cope with their large intensity range (> 70 dB). Position and intensity signals are digitized in the Front-End electronics installed in the tunnel. The data are then transmitted over a serial fibre-optic link to a VME Digital Acquisition board located in surface buildings. A first prototype, equipped with a calibration system, has been successfully tested on the SPS under different beam conditions, including single bunch, 25 ns and 50 ns bunch trains. The system architecture and the first beam measurements are reported in this paper

  3. Prediction of position estimation errors for 3D target trajetories estimated from cone-beam CT projections

    DEFF Research Database (Denmark)

    Poulsen, Per Rugaard; Cho, Byungchul; Keall, Paul

    2010-01-01

    The three-dimensional (3D) trajectory of an implanted tumor marker can be estimated from its projected 2D trajectory in a set of cone-beam CT (CBCT) projections by a probability-based method[1]. The uncertainty in the position estimation depends on the trajectory and varies along a given trajectory...

  4. Energy resolution methods efficiency depending on beam source position of potassium clusters in time-of-flight mass spectrometer

    Indian Academy of Sciences (India)

    Ş Şentürk; F Demiray; O Özsoy

    2007-09-01

    Energy resolution of the time-of-flight mass spectrometer was considered. The estimations indicate that the time-lag energy focusing method provides better resolution for the parallel case while the turnaround time is more convenient for the perpendicular position. Hence the applicability of the methods used for the energy resolution depends on beam source arrangement.

  5. A Fast Non Intercepting Linac Electron Beam Position and Current Monitor

    DEFF Research Database (Denmark)

    Hansen, Jørgen-Walther; Wille, Mads

    1982-01-01

    A non-intercepting beam monitor consisting of four detecting loops is used to determine the spatial postion and current of a pulsed beam from an electron linear accelerator. The monitor detects the magnetic field radiated by the substructure of the electron bunches created by the accelerating...

  6. Evaluation of condylar positions in patients with temporomandibular disorders: A cone-beam computed tomographic study

    Science.gov (United States)

    Imanimoghaddam, Mahrokh; Madani, Azam Sadat; Mahdavi, Pirooze; Bagherpour, Ali; Darijani, Mansoreh

    2016-01-01

    Purpose This study was performed to compare the condylar position in patients with temporomandibular joint disorders (TMDs) and a normal group by using cone-beam computed tomography (CBCT). Materials and Methods In the TMD group, 25 patients (5 men and 20 women) were randomly selected among the ones suffering from TMD according to the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). The control group consisted of 25 patients (8 men and 17 women) with normal temporomandibular joints (TMJs) who were referred to the radiology department in order to undergo CBCT scanning for implant treatment in the posterior maxilla. Linear measurements from the superior, anterior, and posterior joint spaces between the condyle and glenoid fossa were made through defined landmarks in the sagittal view. The inclination of articular eminence was also determined. Results The mean anterior joint space was 2.3 mm in the normal group and 2.8 mm in the TMD group, respectively. The results showed that there was a significant correlation between the superior and posterior joint spaces in both the normal and TMD groups, but it was only in the TMD group that the correlation coefficient among the dimensions of anterior and superior spaces was significant. There was a significant correlation between the inclination of articular eminence and the size of the superior and posterior spaces in the normal group. Conclusion The average dimension of the anterior joint space was different between the two groups. CBCT could be considered a useful diagnostic imaging modality for TMD patients. PMID:27358820

  7. Relative Position Determination between Deep-space Probes Based on Same Beam Phase-referencing Imaging Technique

    Directory of Open Access Journals (Sweden)

    ZHOU Huan

    2015-06-01

    Full Text Available To meet the needs of high accuracy relative position determination in deep space explorations, a new method is proposed based on the same beam phase-referencing imaging technique that originates from the radio astronomy. Firstly, the same beam phase-referencing imaging measurement model for spacecraft positioning is built. The very long baseline interferometry (VLBI imaging principle and the phase difference between two spacecrafts are derived. Then, two precision affecting factors are analyzed, including the signal bandwidth and the UV coverage. The dirty beams formed by different station numbers and different observation lengths with the Chinese interferometry network are simulated. Finally, with the same beam observation data of the Chang'E-3 lander and rover from the Chinese VLBI network (CVN on December 15, 20 and 21, 2013,the Yutu rover lunar surface positions are determined with accuracy of about 1 meter. The results show the feasibility and high accuracy of this method, which is well-adapted to the spacecraft signals without special beacons.

  8. Determination of intensity and position of the extracted electron beam at ELSA by means of high-frequency resonators

    International Nuclear Information System (INIS)

    The electron stretcher facility ELSA provides an electron beam of a few hundred pA used for the generation of bremsstrahlung photons probing the nucleon structure in a detector setup. For the correct interpretation of the events registered, the persistence of the beam position over time is crucial. Its continuous monitoring has been enabled by setting up a measurement system based on resonant cavities. Position signals at a frequency of 1.5 GHz and below one aW of power can be abstracted from the beam without degrading its quality. After frequency down-conversion to a few kHz, a narrow bandwidth detection performed by lock-in amplifiers separates them from noise. A maximum sample rate of 9 Hz and a resolution of one tenth of a millimeter could be achieved. The position signals have to be normalized to the beam current which is monitored by another dedicated resonator. The measurement precision down to a few pA allows for the accelerator extraction mechanism to be controlled by a feedback loop in order to obtain the respective requested current. (orig.)

  9. Exploiting low-gap beam position monitors in orbit stabilization feedback and feed-forward systems at ELETTRA

    Energy Technology Data Exchange (ETDEWEB)

    Bulfone, D.; Forchi, V.; Gaio, G.; Lonza, M. [Sincrotrone Trieste, Trieste (Italy)

    2003-07-01

    Two low-gap electron Beam Position Monitors (BPMs) equipped with digital detector electronics have been installed either side of an Insertion Device (ID) long straight section at ELETTRA. The new BPMs have been integrated in a fast local orbit feedback system that stabilizes the electron beam orbit at the center of the ID. They also provide the basic measurements that are used by a feed-forward correction system compensating for the orbit distortion produced by an Electromagnetic Elliptical Wiggler (EEW) operated at high switching frequencies (up to 100 Hz) of the horizontal field. The main results achieved are presented. (author)

  10. Exploiting low-gap beam position monitors in orbit stabilization feedback and feed-forward systems at ELETTRA

    CERN Document Server

    Bulfone, D; Gaio, G; Lonza, M

    2003-01-01

    Two low-gap electron Beam Position Monitors (BPMs) equipped with digital detector electronics have been installed either side of an Insertion Device (ID) long straight section at ELETTRA. The new BPMs have been integrated in a fast local orbit feedback system that stabilizes the electron beam orbit at the center of the ID. They also provide the basic measurements that are used by a feed-forward correction system compensating for the orbit distortion produced by an Electromagnetic Elliptical Wiggler (EEW) operated at high switching frequencies (up to 100 Hz) of the horizontal field. The main results achieved are presented. (author)

  11. Electromagnetic Design and Optimization of Directivity of Stripline Beam Position Monitors for the High Luminosity Large Hadron Collider

    CERN Document Server

    Draskovic, Drasko; Jones, Owain Rhodri; Lefèvre, Thibaut; Wendt, Manfred

    2015-01-01

    This paper presents the preliminary electromagnetic design of a stripline Beam Position Monitor (BPM) for the High Luminosity program of the Large Hadron Collider (HL-LHC) at CERN. The design is fitted into a new octagonal shielded Beam Screen for the low-beta triplets and is optimized for high directivity. It also includes internal Tungsten absorbers, required to reduce the energy deposition in the superconducting magnets. The achieved broadband directivity in wakefield solver simulations presents significant improvement over the directivity of the current stripline BPMs installed in the LHC.

  12. Effect of horizontal fast electron beam position feedback on the performance of ESRF beamlines

    CERN Document Server

    Pascarelli, S

    2001-01-01

    ESRF is a state of the art third generation synchrotron light source optimized to produce very bright and collimated hard X-ray beams using insertion devices. Instabilities of the electron beam, resulting in source point transverse displacements, spoil these outstanding beam qualities. At the beginning of operation a fast active feedback system was installed to damp the transverse motion of the electron beam in the vertical plane. Recently it became evident that also the relatively smaller horizontal instabilities may have specific detrimental effects on the operation of particularly sensitive beamlines. The dispersive XAS beamline (ID24) was the first to benefit from the activation of a local horizontal feedback. Optimized to perform time-resolved studies and high-pressure experiments, its operation was strongly perturbed. This paper briefly describes the work carried out to identify and solve these problems, presenting the outcome of the implementation of a fast orbit feedback on this beamline.

  13. Ionization profilemeter of the beam position on the target of the fragment-separator COMBAS

    International Nuclear Information System (INIS)

    The work principle of new ionization profilemeter design and results of its testing at the 30 MeV/n ion 40Ar beam are described. The beam density distribution over its cross section obtained with using this equipment is showed. The space resolution of this profilemeter design is 1 x 1 mm. The beam image obtained with using the fluorescent screen is showed for the comparison. It is fixed that the minimum value of the current of the beam, for which its profile can be measured, is 3 nA. The profile distribution is measured at two pressures of the residual gas 2 · 10-3 and 7 · 10-3 Pa. (author)

  14. Energy Recovery from a Space-Charge Neutralized Positive Ion Beam by Means of Magnetic Electron Suppression

    Science.gov (United States)

    Ryan, Philip Michael

    The charge-exchange neutralization efficiency of positive ion based neutral beams used in plasma heating applications decreases as the beam energy increases. Direct energy recovery from the charged particles can be accomplished by electrostatically decelerating the positive ions; the problem is to effect this without accelerating the space -charge neutralizing electrons residing in the beam. Prior work with both electrostatic and magnetic electron suppression is reviewed. A finite difference ion optics code which solves the nonlinear Vlasov-Poisson equation is adapted to energy recovery application and used to analyze the transverse magnetic field electron suppression experiments carried out at Oak Ridge National Laboratory between 1980 and 1982. Three numerical models are discussed and evaluated. The double plasma model, which assumes an equilibrium Boltzmann distribution of electrons at both the neutralizer potential and the ion collector potential, most successfully duplicates the experimental results with beams in the 40 keV, 10 A range. It is used to analyze the effects of the magnetic field strength, the ion "boost" energy, and the ion beam current density on the ion collection efficiency. Conclusions of the study are: (1) the electron leakage current scales as B('-1), necessitating magnetic suppression fields in excess of 0.1 tesla; (2) the neutralizer geometry should provide an electrostatic field to counteract the magnetic force on the ions; (3) fractional energy beam ions should be confined to the neutralizer interior; (4) the neutral line density in the recovery region should be less than 3 x 10('-3) torr(.)cm. Recovery efficiency decreases with increasing beam current density; a net recovery efficiency of 30% (ion collection efficiency of 75%) at 5 mA/cm('2) falls to zero at 10 mA/cm('2) for a 40 keV beam. New designs are presented and analyzed: an ion collection efficiency of close to 90% is predicted for an 80 keV D ion beam with an ion current

  15. The impact of reorienting cone-beam computed tomographic images in varied head positions on the coordinates of anatomical landmarks

    Science.gov (United States)

    Kim, Jae Hun; Hwang, Jae Joon; Lee, Jung-Hee

    2016-01-01

    Purpose The aim of this study was to compare the coordinates of anatomical landmarks on cone-beam computed tomographic (CBCT) images in varied head positions before and after reorientation using image analysis software. Materials and Methods CBCT images were taken in a normal position and four varied head positions using a dry skull marked with 3 points where gutta percha was fixed. In each of the five radiographic images, reference points were set, 20 anatomical landmarks were identified, and each set of coordinates was calculated. Coordinates in the images from the normally positioned head were compared with those in the images obtained from varied head positions using statistical methods. Post-reorientation coordinates calculated using a three-dimensional image analysis program were also compared to the reference coordinates. Results In the original images, statistically significant differences were found between coordinates in the normal-position and varied-position images. However, post-reorientation, no statistically significant differences were found between coordinates in the normal-position and varied-position images. Conclusion The changes in head position impacted the coordinates of the anatomical landmarks in three-dimensional images. However, reorientation using image analysis software allowed accurate superimposition onto the reference positions. PMID:27358821

  16. Relative position determination of a lunar rover using high-accuracy multi-frequency same-beam VLBI

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Multi-frequency same-beam VLBI means that two explorers with a small separation angle are simultaneously observed with the main beam of receiving antennas. In the same-beam VLBI, the differential phase delay between two explorers and two receiving telescopes can be obtained with a small error of several picoseconds. The differential phase delay, as the observable of the same-beam VLBI, gives the separation angular information of the two explorers in the celestial sphere. The two-dimensional relative position on the plane-of-sky can thus be precisely determined with an error of less than 1 m for a distance of 3.8×105 km far away from the earth, by using the differential phase delay obtained with the four Chinese VLBI stations. The relative position of a lunar rover on the lunar surface can be determined with an error of 10 m by using the differential phase delay data and the range data for the lander when the lunar topography near the rover and the lander can be determined with an error of 10 m.

  17. Experimental Test of Data Analysis Methods from Staggered Pair X-ray Beam Position Monitors at Bending Magnet Beamlines

    International Nuclear Information System (INIS)

    Different methods have been proposed to calculate the vertical position of the photon beam centroid from the four blade currents of staggered pair X-ray beam position monitors (XBPMs) at bending magnet beamlines since they emerged about 15 years ago. The original difference-over-sum method introduced by Peatman and Holldack is still widely used, even though it has been proven to be rather inaccurate at large beam displacements. By systematically generating bumps in the electron orbit of the ANKA storage ring and comparing synchronized data from electron BPMs and XBPM blade currents, we have been able to show that the log-ratio method by S. F. Lin, B.G. Sun et al. is superior (meaning the characteristic being closer to linear) to the ratio method, which in turn is superior to the difference over sum method. These findings are supported by simulations of the XBPM response to changes of the beam centroid. The heuristic basis for each of the methods is investigated. The implications on using XBPM readings for orbit correction are discussed

  18. Development of a Turn-by-Turn Beam Position Monitoring System for Multiple Bunch Operation of the ATF Damping Ring

    CERN Document Server

    Burrows, P N; Kraljevic, N Blaskovic; Christian, G B; Davis, M R; Perry, C; Apsimon, R J; Constance, B; Gerbershagen, A; Resta-Lopez, J

    2012-01-01

    An FPGA-based monitoring system has been developed to study multi-bunch beam instabilities in the damping ring (DR) of the KEK Accelerator Test Facility (ATF). The system utilises a stripline beam position monitor (BPM) and single-stage down-mixing BPM processor. The system is designed to record the horizontal and/or vertical positions of up to three bunches in the DR with c. 150ns bunch spacing, or the head bunch of up to three trains in a multi-bunch mode with a bunch spacing of 5.6 ns. The FPGA firmware and data acquisition software allow the recording of turnby-turn data. An overview of the system and performance results will be presented.

  19. Development of a Millimeter-Wave Beam Position and Profile Monitor for Transmission Efficiency Improvement in an ECRH System

    Directory of Open Access Journals (Sweden)

    Shimozuma T.

    2015-01-01

    Full Text Available In a high power Electron Cyclotron Resonance Heating (ECRH system, a long-distance and low-loss transmission system is required to realize effective heating of nuclear fusion-relevant plasmas. A millimeter-wave beam position and profile monitor, which can be used in a high-power, evacuated, and cooled transmission line, is proposed, designed, manufactured, and tested. The beam monitor consists of a reflector, Peltier-device array and a heat-sink. It was tested using simulated electric heater power or gyrotron output power. The data obtained from the monitor were well agreed with the heat source position and profile. The methods of data analysis and mode-content analysis of a propagating millimeter-wave in the corrugated wave-guide are proposed.

  20. Development of a Millimeter-Wave Beam Position and Profile Monitor for Transmission Efficiency Improvement in an ECRH System

    Science.gov (United States)

    Shimozuma, T.; Kobayashi, S.; Ito, S.; Ito, Y.; Kubo, S.; Yoshimura, Y.; Nishiura, M.; Igami, H.; Takahashi, H.; Mizuno, Y.; Okada, K.; Mutoh, T.

    2015-03-01

    In a high power Electron Cyclotron Resonance Heating (ECRH) system, a long-distance and low-loss transmission system is required to realize effective heating of nuclear fusion-relevant plasmas. A millimeter-wave beam position and profile monitor, which can be used in a high-power, evacuated, and cooled transmission line, is proposed, designed, manufactured, and tested. The beam monitor consists of a reflector, Peltier-device array and a heat-sink. It was tested using simulated electric heater power or gyrotron output power. The data obtained from the monitor were well agreed with the heat source position and profile. The methods of data analysis and mode-content analysis of a propagating millimeter-wave in the corrugated wave-guide are proposed.

  1. Fast Beam Investigations of Two- and Three-Body Photodissociation by Time- and Position-Coincidence Imaging

    OpenAIRE

    Crider, Paul

    2010-01-01

    Fast beam photofragment translational spectroscopy has been used to elucidate the photodissociation dynamics of small radicals and closed-shell anions. Imaging of photofragments in time- and position-coincidence allows the determination of mass distributions, translational energy distributions [P(ET) distributions], and in the case of three-body fragmentation channels, ternary Dalitz plots depicting the momentum disposal among the fragments. These data yield information about the potential en...

  2. Positioning.

    Science.gov (United States)

    Conone, Ruth M.

    The key to positioning is the creation of a clear benefit image in the consumer's mind. One positioning strategy is creating in the prospect's mind a position that takes into consideration the company's or agency's strengths and weaknesses as well as those of its competitors. Another strategy is to gain entry into a position ladder owned by…

  3. Prototype Digital Beam Position and Phase Monitor for the 100-MeV Proton Linac of PEFP

    CERN Document Server

    Yu In Ha; Kim, Sung-Chul; Park, In-Soo; Park, Sung-Ju; Tae Kim, Do

    2005-01-01

    The PEFP (Proton Engineering Frontier Project) at the KAERI (Korea Atomic Energy Research Institute) is building a high-power proton linear accelerator aiming to generate 100-MeV proton beams with 20-mA peak current (pulse width and max. repetition rate of 1 ms and 120 Hz respectively). We are developing a prototype digital BPPM (Beam Position and Phase Monitor) for the PEFP linac utilizing the digital technology with field programmable gate array (FPGA). The RF input signals are down converted to 10 MHz and sampled at 40 MHz with 14-bit ADC to produce I and Q data streams. The system is designed to provide a position and phase resolution of 0.1% and 0.1? RMS respectively. The fast digital processing is networked to the EPICS-based control system with an embedded processor (Blackfin). In this paper, the detailed description of the prototype digital beam position and phase monitor will be described with the performance test results.

  4. Status of higher order mode beam position monitors in 3.9 GHz superconducting accelerating cavities at FLASH

    CERN Document Server

    Zhang, P; Jones, R M; Flisgen, T; Van Rienen, U; Shinton, I R R

    2013-01-01

    Higher order mode (HOM) beam position monitors (BPM) are being developed for the 3.9 GHz third harmonic superconducting accelerating cavities at FLASH. The transverse beam position in a cavity can be determined utilizing beam-excited HOMs based on dipole components. The existing couplers used for HOM suppression provide necessary signals. The diagnostics principle is similar to a cavity BPM, but requires no additional vacuum instruments on the linac. The challenges of HOM-BPM for 3.9 GHz cavities lie in the dense HOM spectrum arising from the coupling of the majority HOMs amongst the four cavities in the cryo-module ACC39. HOMs with particularly promising diagnostics features were evaluated using a spectrum analyzer and custom-built test electronics with various data analysis techniques, data reduction was focused on. After careful theoretical and experimental assessment of the HOM spectrum, multi-cavity modes in the region of 5 GHz were chosen to provide a global position over the complete module with superi...

  5. Status of Higher Order Mode Beam Position Monitors in 3.9 GHz Superconducting Accelerating Cavities at FLASH

    CERN Document Server

    Zhang, P; Flisgen, T; van Rienen, U; Jones, R M; Shinton, I R R

    2013-01-01

    Higher order mode (HOM) beam position monitors (BPM) are being developed for the 3.9 GHz third harmonic superconducting accelerating cavities at FLASH. The transverse beam position in a cavity can be determined utilizing beam-excited HOMs based on dipole components. The existing couplers used for HOM suppression provide necessary signals. The diagnostics principle is similar to a cavity BPM, but requires no additional vacuum instruments on the linac. The challenges of HOM-BPM for 3.9 GHz cavities lie in the dense HOM spectrum arising from the coupling of the majority HOMs amongst the four cavities in the cryo-module ACC39. HOMs with particularly promising diagnostics features were evaluated using a spectrum analyzer and custom-built test electronics with various data analysis techniques, data reduction was focused on. After careful theoretical and experimental assessment of the HOM spectrum, multi-cavity modes in the region of 5 GHz were chosen to provide a global position over the complete module with superi...

  6. Whole breast radiotherapy in prone and supine position: is there a place for multi-beam IMRT?

    OpenAIRE

    Mulliez, Thomas; Speleers, Bruno; Madani, Indira; De Gersem, Werner; Veldeman, Liv; De Neve, Wilfried

    2013-01-01

    Background: Early stage breast cancer patients are long-term survivors and finding techniques that may lower acute and late radiotherapy-induced toxicity is crucial. We compared dosimetry of wedged tangential fields (W-TF), tangential field intensity-modulated radiotherapy (TF-IMRT) and multi-beam IMRT (MB-IMRT) in prone and supine positions for whole-breast irradiation (WBI). Methods: MB-IMRT, TF-IMRT and W-TF treatment plans in prone and supine positions were generated for 18 unselected ...

  7. Aperture Restriction Localisation in the LHC Arcs using an RF Mole and the LHC Beam Position Measurement System

    CERN Document Server

    Albertone, J; Boccard, C; Bogey, T; Borowiec, P; Calvo, E; Caspers, Friedhelm; Gasior, M; González, J L; Jenninger, B; Jensen, L K; Jones, O R; Kroyer, T; Weisz, S

    2008-01-01

    Ensuring that the two 27km beam pipes of the LHC do not contain aperture restrictions is of utmost importance. Most of the ring is composed of continuous cryostats, so any intervention to remove aperture restrictions when the machine is at its operating temperature of 1.9K will require a substantial amount of time. On warming-up the first cooled sector, several of the sliding contacts which provide electrical continuity for the beam image current between successive sections of the vacuum chamber were found to have buckled into the beam pipe. This led to a search for a technique to verify the integrity of a complete LHC arc (~3km) before any subsequent cool-down. In this paper the successful results from using a polycarbonate ball fitted with a 40MHz RF transmitter are presented. Propulsion of the ball is achieved by sucking filtered air through the entire arc, while its progress is traced every 54m via the LHC beam position measurement system which is auto-triggered by the RF transmitter on passage of the bal...

  8. Cone-Beam Computed Tomographic Assessment of Mandibular Condylar Position in Patients with Temporomandibular Joint Dysfunction and in Healthy Subjects

    Directory of Open Access Journals (Sweden)

    Maryam Paknahad

    2015-01-01

    Full Text Available Statement of the Problem. The clinical significance of condyle-fossa relationships in the temporomandibular joint is a matter of controversy. Different studies have evaluated whether the position of the condyle is a predictor of the presence of temporomandibular disorder. Purpose. The purpose of the present study was to investigate the condylar position according to gender in patients with temporomandibular disorder (TMD and healthy controls using cone-beam computed tomography. Materials and Methods. CBCT of sixty temporomandibular joints in thirty patients with TMD and sixty joints of thirty subjects without TMJ disorder was evaluated in this study. The condylar position was assessed on the CBCT images. The data were analyzed using Pearson chi-square test. Results. No statistically significant differences were found regarding the condylar position between symptomatic and asymptomatic groups. Posterior condylar position was more frequently observed in women and anterior condylar position was more prevalent in men in the symptomatic group. However, no significant differences in condylar position were found in asymptomatic subjects according to gender. Conclusion. This study showed no apparent association between condylar positioning and clinical findings in TMD patients.

  9. Mechanical design, development, and installation of ultra high vacuum compatible beam position indicators for insertion devices in Indus-2

    International Nuclear Information System (INIS)

    Recently, two insertion devices (undulators) have been installed in long straight sections LS-2 and LS-3 of Indus-2. For precise monitoring of electron beam position at the entry and exit of these insertion devices, 17 mm vertical low gap type ultra high vacuum (UHV) compatible insertion device beam position indicators (IDBPls) have been designed, developed, and installed by Beam Diagnostics Section. The water cooled RF shielded bellows have also been designed, developed, and integrated in IDBPI assembly by Ultra High Vacuum Technology Section. The IDBPI has 17 mm (V) x 81 mm (H) internal race track profile aperture same as of vacuum chamber of insertion device. It incorporates four numbers of electrode subassemblies directly welded (by TIG) to its vacuum chamber. The button diameter is 9 mm. The horizontal separation between buttons is 12 mm. The IDBPI assemblies have been installed in Indus-2 ring and are in operation since Jan 2015. The mechanical design, development procedure and initial results have been described in this paper

  10. High energy electron radiography system design and simulation study of beam angle-position correlation and aperture effect on the images

    Science.gov (United States)

    Zhao, Quantang; Cao, S. C.; Liu, M.; Sheng, X. K.; Wang, Y. R.; Zong, Y.; Zhang, X. M.; Jing, Y.; Cheng, R.; Zhao, Y. T.; Zhang, Z. M.; Du, Y. C.; Gai, W.

    2016-10-01

    A beam line dedicated to high-energy electron radiography experimental research with linear achromat and imaging lens systems has been designed. The field of view requirement on the target and the beam angle-position correlation correction can be achieved by fine-tuning the fields of the quadrupoles used in the achromat in combination with already existing six quadrupoles before the achromat. The radiography system is designed by fully considering the space limitation of the laboratory and the beam diagnostics devices. Two kinds of imaging lens system, a quadruplet and an octuplet system are integrated into one beam line with the same object plane and image plane but with different magnification factor. The beam angle-position correlation on the target required by the imaging lens system and the aperture effect on the images are studied with particle tracking simulation. It is shown that the aperture position is also correlated to the beam angle-position on the target. With matched beam on the target, corresponding aperture position and suitable aperture radius, clear pictures can be imaged by both lens systems. The aperture is very important for the imaging. The details of the beam optical requirements, optimized parameters and the simulation results are presented.

  11. Influences of size and position of defects on the fatigue life of electron beam welded-aluminum alloy joints

    Institute of Scientific and Technical Information of China (English)

    LU Li; ZHAO Haiyan; CAI Zhipeng; CUI Xiaofang

    2007-01-01

    Defects such as pores influence the fatigue life of electron beam-welded aluminum alloy joints. In this paper,the influences of pore size and position on the fatigue life of aluminum overlap joint are studied. A finite element model (FEM), combined with experimental data, is established to evaluate the fatigue life of overlap joints. By employing this FE model, the effects of pore size and position on fatigue lives of overlap joints are investigated and discussed. From the present study, when pore position is closer to the weld bead tip or the faying surface, the fatigue life decreases. Also, there is a critical size for the pore; when the pore size is larger than the critical value, the fatigue strength decreases sharply.

  12. Resolution study of higher-order-mode-based beam position diagnostics using custom-built electronics in strongly coupled 3.9-GHz multi-cavity accelerating module

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, P.; Baboi, N.; Jones, R.M.; Eddy, N.

    2012-11-01

    Beam-excited higher order modes (HOMs) can provide remote diagnostics information of the beam position and cavity misalignment. In this paper we report on recent studies on the resolution with specially selected series of modes with custom-built electronics. This constitutes the first report of measurements of these cavities in which we obtained a resolution of 20 micron in beam offset. Details of the setup of the electronics and HOM measurements are provided.

  13. The LACARA Vacuum Laser Accelerator Experiment: Beam Positioning and Alignment in a Strong Magnetic Field

    International Nuclear Information System (INIS)

    LACARA (laser cyclotron auto-resonance accelerator) is a vacuum laser accelerator of electrons that is under construction at the Accelerator Test Facility (ATF), Brookhaven National Laboratory. It is expected that the experiment will be assembled by September 2006; this paper presents progress towards this goal. According to numerical studies, as an electron bunch moves along the LACARA solenoidal magnetic field (∼5.2 T, length ∼1 m), it will be accelerated from 50 to ∼75 MeV by interacting with a 0.8 TW Gaussian-mode circularly polarized optical pulse provided by the ATF CO2 10.6μm laser system. The LACARA laser transport optics must handle 10 J and be capable of forming a Gaussian beam inside the solenoid with a 1.4 mm waist and a Rayleigh range of 60 cm. The electron optics must transport a bunch having input emittance of 0.015 mm-mrad and 100 μm waist through the magnet. Precision alignment between the electron beam and the solenoid magnetic axis is required, and a method to achieve this is described in detail. Emittance- filtering may be necessary to yield an accelerated bunch having a narrow (∼1%) energy-spread

  14. Simultaneous linear optics and coupling correction for storage rings with turn-by-turn beam position monitor data

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Xi [Brookhaven National Lab. (BNL), Upton, NY (United States); Huang, Xiaobiao [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-11-10

    We propose a method to simultaneously correct linear optics errors and linear coupling for storage rings using turn-by-turn (TbT) beam position monitor (BPM) data. The independent component analysis (ICA) method is used to isolate the betatron normal modes from the measured TbT BPM data. The betatron amplitudes and phase advances of the projections of the normal modes on the horizontal and vertical planes are then extracted, which, combined with dispersion measurement, are used to fit the lattice model. Furthermore, the fitting results are used for lattice correction. Our method has been successfully demonstrated on the NSLS-II storage ring.

  15. Studies of the behavior of a reactor neutron beam at the sample position of a diffractometer using silicon monochromators

    Science.gov (United States)

    Ahmed, F. U.; Ahsan, M. H.; Khan, Aysha A.; Kamal, I.; Awal, M. A.; Ahmad, A. A. Z.

    1992-02-01

    A computer program TISTA has been developed for calculation of different aspects of designing a double axis neutron spectrometer at the TRIGA Mark II research reactor of the Atomic Energy Research Establishment, Dhaka, Bangladesh. The mathematical algorithms used in this program are based on the formalisms used by Fischer, Sabine and Bacon. Angle and energy resolutions and flux density as functions of neutron wave length, beam collimation, crystal asymmetry and deviation from zero-Bragg-angle position for different silicon crystal planes (111, 220, 311) have been calculated.

  16. Simultaneous linear optics and coupling correction for storage rings with turn-by-turn beam position monitor data

    CERN Document Server

    Yang, Xi

    2015-01-01

    We propose a method to simultaneously correct linear optics errors and linear coupling for storage rings using turn-by-turn (TbT) beam position monitor (BPM) data. The independent component analysis (ICA) method is used to isolate the betatron normal modes from the measured TbT BPM data. The betatron amplitudes and phase advances of the projections of the normal modes on the horizontal and vertical planes are then extracted, which, combined with dispersion measurement, are used to fit the lattice model. The fitting results are used for lattice correction. The method has been successfully demonstrated on the NSLS-II storage ring.

  17. A study of beam position diagnostics with beam-excited dipole higher order modes using a downconverter test electronics in third harmonic 3.9 GHz superconducting accelerating cavities at FLASH

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, P. [Manchester Univ. (United Kingdom); Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Baboi, N.; Lorbeer, B.; Wamsat, T. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Eddy, N.; Fellenz, B.; Wendt, M. [Fermi National Accelerator Lab., Batavia, IL (United States); Jones, R.M. [Manchester Univ. (United Kingdom); The Cockcroft Institute, Daresbury (United Kingdom)

    2012-08-15

    Beam-excited higher order modes (HOM) in accelerating cavities contain transverse beam position information. Previous studies have narrowed down three modal options for beam position diagnostics in the third harmonic 3.9 GHz cavities at FLASH. Localized modes in the beam pipes at approximately 4.1 GHz and in the fifth cavity dipole band at approximately 9 GHz were found, that can provide a local measurement of the beam position. In contrast, propagating modes in the first and second dipole bands between 4.2 and 5.5 GHz can reach a better resolution. All the options were assessed with a specially designed test electronics built by Fermilab. The aim is to de ne a mode or spectral region suitable for the HOM electronics. Two data analysis techniques are used and compared in extracting beam position information from the dipole HOMs: direct linear regression and singular value decomposition. Current experiments suggest a resolution of 50 m accuracy in predicting local beam position using modes in the fifth dipole band, and a global resolution of 20 m over the complete module. Based on these results we decided to build a HOM electronics for the second dipole band and the fifth dipole band, so that we will have both high resolution measurements for the whole module, and localized measurements for individual cavity. The prototype electronics is being built by Fermilab and planned to be tested in FLASH by the end of 2012.

  18. Correction of patient positioning errors based on in-line cone beam CTs: clinical implementation and first experiences

    Directory of Open Access Journals (Sweden)

    Häring Peter

    2006-05-01

    Full Text Available Abstract Background The purpose of the study was the clinical implementation of a kV cone beam CT (CBCT for setup correction in radiotherapy. Patients and methods For evaluation of the setup correction workflow, six tumor patients (lung cancer, sacral chordoma, head-and-neck and paraspinal tumor, and two prostate cancer patients were selected. All patients were treated with fractionated stereotactic radiotherapy, five of them with intensity modulated radiotherapy (IMRT. For patient fixation, a scotch cast body frame or a vacuum pillow, each in combination with a scotch cast head mask, were used. The imaging equipment, consisting of an x-ray tube and a flat panel imager (FPI, was attached to a Siemens linear accelerator according to the in-line approach, i.e. with the imaging beam mounted opposite to the treatment beam sharing the same isocenter. For dose delivery, the treatment beam has to traverse the FPI which is mounted in the accessory tray below the multi-leaf collimator. For each patient, a predefined number of imaging projections over a range of at least 200 degrees were acquired. The fast reconstruction of the 3D-CBCT dataset was done with an implementation of the Feldkamp-David-Kress (FDK algorithm. For the registration of the treatment planning CT with the acquired CBCT, an automatic mutual information matcher and manual matching was used. Results and discussion Bony landmarks were easily detected and the table shifts for correction of setup deviations could be automatically calculated in all cases. The image quality was sufficient for a visual comparison of the desired target point with the isocenter visible on the CBCT. Soft tissue contrast was problematic for the prostate of an obese patient, but good in the lung tumor case. The detected maximum setup deviation was 3 mm for patients fixated with the body frame, and 6 mm for patients positioned in the vacuum pillow. Using an action level of 2 mm translational error, a target point

  19. RF device for precision location of the beam-position detectors in the Energy Saver

    Energy Technology Data Exchange (ETDEWEB)

    Kerns, Q.A.; Biallas, G.H.; Turkot, F.; Webber, R.C.; Wehmann, A.

    1983-03-01

    The task is to measure the center line of the beam detector with respect to the magnetic centerline with a precision of +-0.2 mm; the measurement must be made on 250 magnets (they come in 6 lengths, from 25'' to 99'') by a technician. Optical, mechanical, and electrical techniques for carrying out this procedure were considered. An RF device operating at 53 MHZ was adopted for the following reasons: (a) it provides complete electrical checkout of the hardware at operating frequency, including the bidirectional operation of the pickup, (b) no mechanical contact with the strip lines is required, and (c) the demands of production measurements and maintenance of calibration are better matched to the skills of an average technician. We describe the conceptual design, fabrication, and performance of this device.

  20. Correlation between hyoid bone position and airway dimensions in Chinese adolescents by cone beam computed tomography analysis.

    Science.gov (United States)

    Jiang, Y-Y

    2016-07-01

    This study aimed to investigate the correlation between upper airway dimensions and hyoid bone position in Chinese adolescents based on cone beam computed tomography (CBCT) images. CBCT images from a total of 254 study subjects were included. The upper airway and hyoid bone parameters were measured by Materialism's interactive medical image control system (MIMICS) v.16.01 (Materialise, Leuven, Belgium). The airway dimensions were evaluated in terms of volume, cross-sectional area (CSA), mean CSA, length, anteroposterior dimension of the cross-section (AP), lateral dimension of the cross-section (LAT), and LAT/AP ratio. The hyoid bone position was evaluated using eight linear parameters and two angular parameters. Facial characteristics were evaluated using three linear parameters and three angular parameters. Most hyoid bone position parameters (especially the distance between the hyoid bone and hard palate) were significantly associated with most airway dimension parameters. Significant correlations were also observed between the different facial characteristic parameters and hyoid bone position parameters. Most airway dimension parameters showed significant correlations with linear facial parameters, but they displayed significant correlations with only a few angular facial parameters. These findings provide an understanding of the static relationship between the hyoid bone position and airway dimensions, which may serve as a reference for surgeons before orthodontic or orthognathic surgery.

  1. Correlation between hyoid bone position and airway dimensions in Chinese adolescents by cone beam computed tomography analysis.

    Science.gov (United States)

    Jiang, Y-Y

    2016-07-01

    This study aimed to investigate the correlation between upper airway dimensions and hyoid bone position in Chinese adolescents based on cone beam computed tomography (CBCT) images. CBCT images from a total of 254 study subjects were included. The upper airway and hyoid bone parameters were measured by Materialism's interactive medical image control system (MIMICS) v.16.01 (Materialise, Leuven, Belgium). The airway dimensions were evaluated in terms of volume, cross-sectional area (CSA), mean CSA, length, anteroposterior dimension of the cross-section (AP), lateral dimension of the cross-section (LAT), and LAT/AP ratio. The hyoid bone position was evaluated using eight linear parameters and two angular parameters. Facial characteristics were evaluated using three linear parameters and three angular parameters. Most hyoid bone position parameters (especially the distance between the hyoid bone and hard palate) were significantly associated with most airway dimension parameters. Significant correlations were also observed between the different facial characteristic parameters and hyoid bone position parameters. Most airway dimension parameters showed significant correlations with linear facial parameters, but they displayed significant correlations with only a few angular facial parameters. These findings provide an understanding of the static relationship between the hyoid bone position and airway dimensions, which may serve as a reference for surgeons before orthodontic or orthognathic surgery. PMID:26949129

  2. Large Size High Performance Transparent Amorphous Silicon Sensors for Laser Beam Position Detection and Monitoring

    International Nuclear Information System (INIS)

    We present the measured performance of a new generation of semitransparente amorphous silicon position detectors. They have a large sensitive area (30 x 30 mm2) and show good properties such as a high response (about 20 mA/W), an intinsic position resolution better than 3 m, a spatial point reconstruction precision better than 10 m, deflection angles smaller than 10 rad and a transmission power in the visible and NIR higher than 70%. In addition, multipoint alignment monitoring, using up to five sensors lined along a light path of about 5 meters, can be achieved with a resolution better than 20m. (Author)

  3. Large-size high-performance transparent amorphous silicon sensors for laser beam position detection

    Energy Technology Data Exchange (ETDEWEB)

    Calderon, A. [Instituto de Fisica de Cantabria. CSIC-University of Cantabria, Santander (Spain); Martinez-Rivero, C. [Instituto de Fisica de Cantabria. CSIC-University of Cantabria, Santander (Spain); Matorras, F. [Instituto de Fisica de Cantabria. CSIC-University of Cantabria, Santander (Spain); Rodrigo, T. [Instituto de Fisica de Cantabria. CSIC-University of Cantabria, Santander (Spain); Sobron, M. [Instituto de Fisica de Cantabria. CSIC-University of Cantabria, Santander (Spain); Vila, I. [Instituto de Fisica de Cantabria. CSIC-University of Cantabria, Santander (Spain); Virto, A.L. [Instituto de Fisica de Cantabria. CSIC-University of Cantabria, Santander (Spain); Alberdi, J. [CIEMAT, Madrid (Spain); Arce, P. [CIEMAT, Madrid (Spain); Barcala, J.M. [CIEMAT, Madrid (Spain); Calvo, E. [CIEMAT, Madrid (Spain); Ferrando, A. [CIEMAT, Madrid (Spain)]. E-mail: antonio.ferrando@ciemat.es; Josa, M.I. [CIEMAT, Madrid (Spain); Luque, J.M. [CIEMAT, Madrid (Spain); Molinero, A. [CIEMAT, Madrid (Spain); Navarrete, J. [CIEMAT, Madrid (Spain); Oller, J.C. [CIEMAT, Madrid (Spain); Yuste, C. [CIEMAT, Madrid (Spain); Koehler, C. [Steinbeis-Transferzentrum fuer Angewandte Photovoltaik und Duennschichttechnik, Stuttgart (Germany); Lutz, B. [Steinbeis-Transferzentrum fuer Angewandte Photovoltaik und Duennschichttechnik, Stuttgart (Germany); Schubert, M.B. [Steinbeis-Transferzentrum fuer Angewandte Photovoltaik und Duennschichttechnik, Stuttgart (Germany); Werner, J.H. [Steinbeis-Transferzentrum fuer Angewandte Photovoltaik und Duennschichttechnik, Stuttgart (Germany)

    2006-09-15

    We present the measured performance of a new generation of semitransparent amorphous silicon position detectors. They have a large sensitive area (30x30mm{sup 2}) and show good properties such as a high response (about 20mA/W), an intrinsic position resolution better than 3{mu}m, a spatial-point reconstruction precision better than 10{mu}m, deflection angles smaller than 10{mu}rad and a transmission power in the visible and NIR higher than 70%.

  4. Large Size High Performance Transparent Amorphous Silicon Sensors for Laser Beam Position Detection and Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Calderon, A.; Martinez Rivero, C.; Matorras, F.; Rodrigo, T.; Sobron, M.; Vila, I.; Virto; Alberdi, J.; Arce, P.; Barcala, J. M.; Calvo, E.; Ferrando, A.; Josa, M. I.; Luque, J. M.; Molinero, A.; Navarrete, J.; Oller, J. C.; Kohler, C.; Lutz, B.; Schubert, M. B.

    2006-09-04

    We present the measured performance of a new generation of semitransparente amorphous silicon position detectors. They have a large sensitive area (30 x 30 mm2) and show good properties such as a high response (about 20 mA/W), an intinsic position resolution better than 3 m, a spatial point reconstruction precision better than 10 m, deflection angles smaller than 10 rad and a transmission power in the visible and NIR higher than 70%. In addition, multipoint alignment monitoring, using up to five sensors lined along a light path of about 5 meters, can be achieved with a resolution better than 20m. (Author)

  5. Proposal for the award of a contract for the supply of vacuum button feedthroughs for the LHC beam position monitors

    CERN Document Server

    2000-01-01

    This document concerns the award of a contract for the supply of 4250 button feedthroughs for the LHC beam position monitors. Following a market survey carried out among 42 firms in fourteen Member States and two firms in the USA and a price enquiry for qualifying prototypes sent to five firms and a consortium comprising two firms in the Member States and to two firms in the USA (DO-17399/SL/LHC) a call for tenders (IT-2530/SL/LHC) was sent on 21 February 2000 to two firms in the USA. By the closing date, CERN had received two tenders. The Finance Committee is invited to agree to the negotiation of a contract with the firm CERAMASEAL (USA), the lowest bidder, for the supply of 4250 button feedthroughs for the LHC beam position monitors for a total amount of 897 524 USD (1 468 222 Swiss francs), not subject to revision, with an option for the supply of up to 500 additional button feedthroughs, for a total amount of 105 590 USD (172 730 Swiss francs), not subject to revision, bringing the total amount to a maxi...

  6. Simple technique to achieve a natural position of the head for cone beam computed tomography

    NARCIS (Netherlands)

    Damstra, Janalt; Fourie, Zacharias; Ren, Yijin

    2010-01-01

    We developed a modified laser level technique to record the natural position of the head in all three planes of space. This is a simple method for use with three-dimensional images and may be valuable in routine craniofacial assessment.

  7. Design, development, and performance of an adapter for simulation of ocular melanoma patients in supine position for proton beam therapy

    Science.gov (United States)

    Daftari, I.; Phillips, T. L.

    2003-06-01

    A patient assembly adapter system for ocular melanoma patient simulation was developed and its performance evaluated. The aim for the construction of the apparatus was to simulate the patients in supine position using a commercial x-ray simulator. The apparatus consists of a base plate, head immobilization holder, patient assembly system that includes fixation light and collimator system. The reproducibility of the repeated fixation was initially tested with a head phantom. Simulation and verification films were studied for seven consecutive patients treated with proton beam therapy. Patient's simulation was performed in a supine position using a dental fixation bite block and a thermoplastic head mask immobilization device with a patient adapter system. Two orthogonal x rays were used to obtain the x, y, and z coordinates of sutured tantalum rings for treatment planning with the EYEPLAN software. The verification films were obtained in treatment position with the fixation light along the central axis of the eye. The results indicate good agreement within 0.5 mm deviations. The results of this investigation showed that the same planning accuracy could be achieved by performing simulation using the adapter described above with a patient in the supine position as that obtained by performing simulation with the patient in the seated, treatment position. The adapter can also be attached to the head of the chair for simulating in the seated position using a fixed x-ray unit. This has three advantages: (1) this will save radiation therapists time; (2) it eliminates the need for arranging access to the treatment room, thus avoiding potential conflicts in treatment room usage; and (3) it allows the use of a commercial simulator.

  8. Development of EPICS based beam-line experimental control employing motor controller for precision positioning

    International Nuclear Information System (INIS)

    In a Synchrotron Radiation Source the beamline experiments are carried out in radiation prone environment, inside the hutch, which demands to conduct experiments remotely. These experiments involves instrument control and data acquisition from various devices. Another factor which attributes to system complexity is precise positioning of sample and placement of detectors. A large number of stepper motors are engaged for achieving the required precision positioning. This work is a result of development of Experimental Physics and Industrial Control System (EPICS) based control system to interface a stepper motor controller developed indigenously by Laser Electronics Support Division of RRCAT. EPICS is an internationally accepted open source software environment which follows toolkit approach and standard model paradigm. The operator interface for the control system software was implemented using CSS BOY. The system was successfully tested for Ethernet based remote access. The developed control software comprises of an OPI and alarm handler (EPICS ALH). Both OPI and ALH are linked with PV's defined in database files. The development process resulted into a set of EPICS based commands for controlling stepper motor. These commands are independent of operator interface, i.e. stepper motor can be controlled by using these set of commands directly on EPICS prompt. This command set is illustrated in the above table. EPICS Alarm Handler was also tested independently by running these commands on EPIC prompt. If not using ALH, operator can read the alarm status of a PV using 'SEVR' and 'STAT' attributes. (author)

  9. Positioning of a plane-parallel ionization chamber in clinical electron beams and the impact on perturbation factors.

    Science.gov (United States)

    Zink, K; Wulff, J

    2009-04-21

    Current dosimetry protocols recommend the use of plane-parallel ionization chambers for the dosimetry of clinical electron beams. The necessary perturbation corrections p(wall) and p(cav) are assumed to be unity, independent of the depth of measurement and the energy of the primary electrons. To verify these assumptions detailed Monte Carlo studies of a Roos chamber in clinical electron beams with energies in the range of 6-21 MeV are performed at different depths in water and analyzed in terms of Spencer-Attix cavity theory. Separate simulations for the perturbation corrections p(wall) and p(cav) indicate quite different properties of both correction factors with depth. Dose as well as fluence calculations show a nearly depth-independent wall correction factor for a shift of the Roos chamber Deltaz = -0.017 cm toward the focus. This value is in good agreement with the positioning recommendation given in all dosimetry protocols. Regarding the fluence perturbation p(cav) the simulation of the electron fluence inside the air cavity in comparison to water unambiguously reveals an in-scattering of low energy electrons, despite the fact, that the cavity is 'well guarded'. For depths beyond the reference depth z(ref) this effect is superimposed by an increased loss of primary electrons from the beam resulting in p(cav) > 1. This effect is largest for low electron energies but present for all electron energies involved in this study. Based on the different depth dependences of p(wall) and p(cav) it is possible to choose a chamber shift Deltaz in a way to minimize the depth dependence of the overall perturbation factor p. For the Roos chamber this shift is Deltaz = -0.04 cm independent of electron energy.

  10. Interfractional Position Variation of Pancreatic Tumors Quantified Using Intratumoral Fiducial Markers and Daily Cone Beam Computed Tomography

    Energy Technology Data Exchange (ETDEWEB)

    Horst, Astrid van der, E-mail: a.vanderhorst@amc.uva.nl [Department of Radiation Oncology, Academic Medical Center, University of Amsterdam, Amsterdam (Netherlands); Wognum, Silvia; Dávila Fajardo, Raquel; Jong, Rianne de [Department of Radiation Oncology, Academic Medical Center, University of Amsterdam, Amsterdam (Netherlands); Hooft, Jeanin E. van; Fockens, Paul [Department of Gastroenterology and Hepatology, Academic Medical Center, University of Amsterdam, Amsterdam (Netherlands); Tienhoven, Geertjan van; Bel, Arjan [Department of Radiation Oncology, Academic Medical Center, University of Amsterdam, Amsterdam (Netherlands)

    2013-09-01

    Purpose: The aim of this study was to quantify interfractional pancreatic position variation using fiducial markers visible on daily cone beam computed tomography (CBCT) scans. In addition, we analyzed possible migration of the markers to investigate their suitability for tumor localization. Methods and Materials: For 13 pancreatic cancer patients with implanted Visicoil markers, CBCT scans were obtained before 17 to 25 fractions (300 CBCTs in total). Image registration with the reference CT was used to determine the displacement of the 2 to 3 markers relative to bony anatomy and to each other. We analyzed the distance between marker pairs as a function of time to identify marker registration error (SD of linear fit residuals) and possible marker migration. For each patient, we determined the mean displacement of markers relative to the reference CT (systematic position error) and the spread in displacements (random position error). From this, we calculated the group systematic error, Σ, and group random error, σ. Results: Marker pair distances showed slight trends with time (range, −0.14 to 0.14 mm/day), possibly due to tissue deformation, but no shifts that would indicate marker migration. The mean SD of the fit residuals was 0.8 mm. We found large interfractional position variations, with for 116 of 300 (39%) fractions a 3-dimensional vector displacement of >10 mm. The spread in displacement varied significantly (P<.01) between patients, from a vector range of 9.1 mm to one of 24.6 mm. For the patient group, Σ was 3.8, 6.6, and 3.5 mm; and σ was 3.6, 4.7 and 2.5 mm, in left–right, superior–inferior, and anterior–posterior directions, respectively. Conclusions: We found large systematic displacements of the fiducial markers relative to bony anatomy, in addition to wide distributions of displacement. These results for interfractional position variation confirm the potential benefit of using fiducial markers rather than bony anatomy for daily online

  11. Simultaneous spatial and angular positioning of plane specular samples by a novel double beam triangulation probe with full auto-compensation

    Science.gov (United States)

    Makai, Janos P.

    2016-02-01

    The positioning of a plane specular sample to be measured or processed is an important requirement in many fields of research and industry. Where a sample is to be processed either by electromagnetic waves or a particle beam of higher numerical aperture the irradiance or the particle number over unit area is position and angle dependent. Where optical properties of a sample are to be measured, such as in spectrophotometry, these parameters can depend on the angle of incidence and on the value of the irradiance, i.e. on the angular and spatial position of the sample. In some cases parameters of many samples have to be compared among each other or to those of a standard, this also requires the highly accurate positioning of each sample to the same position. This paper describes a method that is suitable for high accuracy alignment of specular plane samples both angularly and spatially. It applies a double beam triangulation probe, where the second beam serves not only as a reference beam to compensate for any changes of the transmitting media and that of the laser but also doubles the sensitivity of the probe. The method does not compete with interferometric methods, it is required only in special applications, but provides an absolute uncertainty for spatial positioning in the sub-micrometer range and an angular one in the 0.0003° range. Furthermore, the accuracy is tunable by the parameters of the setup.

  12. "DIAGNOSTIC" PULSE FOR SINGLE-PARTICLE-LIKE BEAM POSITION MEASUREMENTS DURING ACCUMULATION/PRODUCTION MODE IN THE LOS ALAMOS PROTON STORAGE RING

    Energy Technology Data Exchange (ETDEWEB)

    Kolski, Jeffrey S. [Los Alamos National Laboratory; Baily, Scott A. [Los Alamos National Laboratory; Bjorklund, Eric A. [Los Alamos National Laboratory; Bolme, Gerald O. [Los Alamos National Laboratory; Hall, Michael J. [Los Alamos National Laboratory; Kwon, Sung I. [Los Alamos National Laboratory; Martinez, Martin P. [Los Alamos National Laboratory; Prokop, Mark S. [Los Alamos National Laboratory; Shelley, Fred E. Jr. [Los Alamos National Laboratory; Torrez, Phillip A. [Los Alamos National Laboratory

    2012-05-14

    Beam position monitors (BPMs) are the primary diagnostic in the Los Alamos Proton Storage Ring (PSR). When injecting one turn, the transversemotion is approximated as a single particle with initial betatron position and angle {rvec x}{sub 0} and {rvec x}'{sub 0}. With single-turn injection, we fit the betatron tune, closed orbit (CO), and injection offset ({rvec x}{sub 0} and {rvec x}'{sub 0} at the injection point) to the turn-by-turn beam position. In production mode, we accumulate multiple turns, the transverse phase space fills after 5 injections (horizontal and vertical fractional betatron tunes {approx}0.2) resulting in no coherent betatron motion, and only the CO may be measured. The injection offset, which determines the accumulated beam size and is very sensitive to steering upstream of the ring, is not measurable in production mode. We describe our approach and ongoing efforts to measure the injection offset during production mode by injecting a 'diagnostic' pulse {approx}50 {micro}s after the accumulated beam is extracted. We also study the effects of increasing the linac RF gate length to accommodate the diagnostic pulse on the production beam position, transverse size, and loss.

  13. An OpenMP Parallelisation of Real-time Processing of CERN LHC Beam Position Monitor Data

    CERN Document Server

    Renshall, H

    2012-01-01

    SUSSIX is a FORTRAN program for the post processing of turn-by-turn Beam Position Monitor (BPM) data, which computes the frequency, amplitude, and phase of tunes and resonant lines to a high degree of precision. For analysis of LHC BPM data a specific version run through a C steering code has been implemented in the CERN Control Centre to run on a server under the Linux operating system but became a real time computational bottleneck preventing truly online study of the BPM data. Timing studies showed that the independent processing of each BPMs data was a candidate for parallelization and the Open Multiprocessing (OpenMP) package with its simple insertion of compiler directives was tried. It proved to be easy to learn and use, problem free and efficient in this case reaching a factor of ten reductions in real-time over twelve cores on a dedicated server. This paper reviews the problem, shows the critical code fragments with their OpenMP directives and the results obtained.

  14. lon-beam analysis of plasma of HIV-Aids positive individual patients and comparison to CD4 counts

    Energy Technology Data Exchange (ETDEWEB)

    Mars, J.A.; Kunsevi-Kilola, C. [Department of Biomedical Sciences, Cape Peninsula University of Technology, PO Box 1906. Bellville, 7535 (South Africa); Maqutu, M.L.; Kunsevi-Kilola, C; Mohammed, A. [HIV-Aids Unit, Cape Peninsula Universily of Technology, PO Box 1906, Bellville, 7535, (South Africa); Tarr, S. [National Health Training College, Private Bag A18, Maseru, Lesotho (South Africa)

    2013-07-01

    Full text: HIV-Aids related diseases have claimed the lives of many individuals, especially those that are economically active. This economic burden has crippled many economies since many of the lives claimed are those of individuals with special skills. However, the pathogenesis of human immuno-deficiency virus (HIV) infection is until present not fully understood. Elements such as Ca, Mg, Fe, Cu, Zn and Se are incorporated into the structure of many enzymes and are therefore essential to the enzyme function. The focus of this study is the correlation of trace element concentrations, determined by IBA, and the CD4 count. Blood obtained from 100 HIV sero-positive males and females attending clinics at the National Health Training College in Maseru metropolis, Lesotho. The CD4 cells of the samples were determined by flow cytometry (Cytoflow SL - S using CD4/CD45 monoclonal antibody and SSC/F12 getting strategy). Afterwards the plasma specimens were freeze dried and then pulverized into palettes. The palettes were coated with carbon and then irradiated with a proton beam of 3 MeV energy. X-ray emission and backscattering data were obtained and then quantified with various computational software. (author)

  15. lon-beam analysis of plasma of HIV-Aids positive individual patients and comparison to CD4 counts

    International Nuclear Information System (INIS)

    Full text: HIV-Aids related diseases have claimed the lives of many individuals, especially those that are economically active. This economic burden has crippled many economies since many of the lives claimed are those of individuals with special skills. However, the pathogenesis of human immuno-deficiency virus (HIV) infection is until present not fully understood. Elements such as Ca, Mg, Fe, Cu, Zn and Se are incorporated into the structure of many enzymes and are therefore essential to the enzyme function. The focus of this study is the correlation of trace element concentrations, determined by IBA, and the CD4 count. Blood obtained from 100 HIV sero-positive males and females attending clinics at the National Health Training College in Maseru metropolis, Lesotho. The CD4 cells of the samples were determined by flow cytometry (Cytoflow SL - S using CD4/CD45 monoclonal antibody and SSC/F12 getting strategy). Afterwards the plasma specimens were freeze dried and then pulverized into palettes. The palettes were coated with carbon and then irradiated with a proton beam of 3 MeV energy. X-ray emission and backscattering data were obtained and then quantified with various computational software. (author)

  16. Design of a vacuum-compatible high-precision monochromatic beam-position monitor for use with synchrotron radiation from 5 to 25 keV.

    Science.gov (United States)

    Alkire, R W; Rosenbaum, G; Evans, G

    2000-03-01

    The Structural Biology Center beamline, 19ID, has been designed to take full advantage of the highly intense undulator radiation and very low source emittance available at the Advanced Photon Source. In order to keep the X-ray beam focused onto the pre-sample slits, a novel position-sensitive PIN diode array has been developed. The array consists of four PIN diodes positioned upstream of a 0.5 microm-thick metal foil placed in the X-ray beam. Using conventional difference-over-the-sum techniques, two-dimensional position information is obtained from the metal foil fluorescence. Because the full X-ray beam passes through the metal foil, the true beam center-of-mass is measured. The device is compact, inexpensive to construct, operates in a vacuum and has a working range of 8 mm x 10 mm that can be expanded with design modifications. Measured position sensitivity is 1-2 microm. Although optimized for use in the 5-25 keV energy range, the upper limit can be extended by changing metals or adjusting foil thickness. PMID:16609175

  17. Position of the impacted third molar in relation to the mandibular canal. Diagnostic accuracy of cone beam computed tomography compared with panoramic radiography.

    NARCIS (Netherlands)

    Ghaeminia, H.; Meijer, G.J.; Soehardi, A.; Borstlap, W.A.; Mulder, J.; Berge, S.J.

    2009-01-01

    This study investigated the diagnostic accuracy of cone beam computed tomography (CBCT) compared to panoramic radiography in determining the anatomical position of the impacted third molar in relation with the mandibular canal. The study sample comprised 53 third molars from 40 patients with an incr

  18. Assessment of the effective dose in supine, prone, and oblique positions in the maxillofacial region using a novel combined extremity and maxillofacial cone beam computed tomography scanner

    NARCIS (Netherlands)

    J. Koivisto; J. Wolff; J. Järnstedt; P. Dastidar; M. Kortesniemi

    2014-01-01

    Objective The objectives of this study were to assess the organ and effective doses (International Commission on Radiological Protection [ICRP] 103 standard) resulting from supine, prone, and oblique phantom positions in the maxillofacial region using a novel cone beam computed tomography (CBCT) dev

  19. Assessment of the Anatomical Position and Shape of Mental Foramen in the Cone Beam Computed Tomography Images

    Directory of Open Access Journals (Sweden)

    A. Eskandarlo

    2012-07-01

    Full Text Available Introduction & Objective: The mental foramen is a part of lower jaw which has neurovascular bundles and also is important in biology. 3D imaging of this area by cone beam computed tomography (CBCT before surgery can prevent some problems. This study aims to evaluate the anatomic position and geometrical shape of the mental foramen by CBCT imagesMaterials & Methods: In this research, the CBCT images (by NewTom and Planmeca promax 3D set of 85 patients referred to dentistry school clinic or other clinics in Hamadan city were studied. These patients did not have their first and second premolar teeth extracted in both right and left sides. The geometrical shape of mental foramen, the canal angle connecting to mental foramen compared to the buccal plate of lower jaw, distance from the lower border of mental foramen to the lower border of lower jaw, position of mental foramen relating to the root of adjacent tooth and the incidence of accessory mental foramen were studied.Results: The means of canal angle connecting to mental foramen in the right side in men and women were 123.3 and 130.1 and in the left side were 123.8 and 133.7, respectively. The mean distance from the lower border of mental foramen to the lower border of lower jaw in the right side in men and women were: 12.4 and 13.3 mm and in the left side were: 12.7 and 13.6 mm, respectively. Also, there is a meaningful statistical relation between gender and the angle of canal of mental foramen, regarding to the buccal plate in both sides.Conclusion: Regarding to the variations in the position and shape of mental foramen and the angle connecting to the mental foramen related to the buccal plate and accessory mental foramen, investigation of CBCT images before placement of implants is necessary.(Sci J Hamadan Univ Med Sci 2012;19(2:39-43

  20. Effect of laser beam position on mechanical properties of F82H/SUS316L butt-joint welded by fiber laser

    International Nuclear Information System (INIS)

    Highlights: • The micro hardness of weld metal in F82H/SUS316L joint partially decreases after PWHT by shifting beam position to SUS316L. • Charpy impact energy of F82H/SUS316L joint obviously increases after PWHT due to the release of residual stress. • The tensile strength of weld metal in F82H/SUS316L joint is higher than that of SUS316L. • The fiber laser welding seems to be one of the most candidate methods to join between F82H and SUS316L pipes practically. - Abstract: A dissimilar butt-joint between reduced activation ferritic/martensitic steel F82H and SUS316L austenitic stainless steel was made by 4 kW fiber laser and the influence of laser beam position on its mechanical properties before and after post-weld heat treatment (PWHT) was examined at room temperature. From the nano-indentation measurements and the microstructural observations, it is found that the micro hardness of weld metal partially decreases after PWHT by shifting beam position to SUS316L because its phase seems to move from only the martensitic phase to the mixture of austenitic and martensitic phases. In addition, Charpy impact test suggests that the impact energy slightly increases by shifting beam position before PWHT and obviously increases after PWHT due to the release of residual stress. Moreover, the tensile test indicates that the tensile strength of weld metal is higher than that of SUS316L and the fracture occurs at the base metal of SUS316L regardless of laser beam position

  1. Effect of laser beam position on mechanical properties of F82H/SUS316L butt-joint welded by fiber laser

    Energy Technology Data Exchange (ETDEWEB)

    Serizawa, Hisashi, E-mail: serizawa@jwri.osaka-u.ac.jp [Joining and Welding Research Institute, Osaka University, 11-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Mori, Daiki; Ogiwara, Hiroyuki; Mori, Hiroaki [Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)

    2014-10-15

    Highlights: • The micro hardness of weld metal in F82H/SUS316L joint partially decreases after PWHT by shifting beam position to SUS316L. • Charpy impact energy of F82H/SUS316L joint obviously increases after PWHT due to the release of residual stress. • The tensile strength of weld metal in F82H/SUS316L joint is higher than that of SUS316L. • The fiber laser welding seems to be one of the most candidate methods to join between F82H and SUS316L pipes practically. - Abstract: A dissimilar butt-joint between reduced activation ferritic/martensitic steel F82H and SUS316L austenitic stainless steel was made by 4 kW fiber laser and the influence of laser beam position on its mechanical properties before and after post-weld heat treatment (PWHT) was examined at room temperature. From the nano-indentation measurements and the microstructural observations, it is found that the micro hardness of weld metal partially decreases after PWHT by shifting beam position to SUS316L because its phase seems to move from only the martensitic phase to the mixture of austenitic and martensitic phases. In addition, Charpy impact test suggests that the impact energy slightly increases by shifting beam position before PWHT and obviously increases after PWHT due to the release of residual stress. Moreover, the tensile test indicates that the tensile strength of weld metal is higher than that of SUS316L and the fracture occurs at the base metal of SUS316L regardless of laser beam position.

  2. Determination of intensity and position of the extracted electron beam at ELSA by means of high-frequency resonators; Bestimmung von Intensitaet und Position des extrahierten Elektronenstrahls an ELSA mittels Hochfrequenzresonatoren

    Energy Technology Data Exchange (ETDEWEB)

    Pusch, Thorsten

    2012-06-15

    The electron stretcher facility ELSA provides an electron beam of a few hundred pA used for the generation of bremsstrahlung photons probing the nucleon structure in a detector setup. For the correct interpretation of the events registered, the persistence of the beam position over time is crucial. Its continuous monitoring has been enabled by setting up a measurement system based on resonant cavities. Position signals at a frequency of 1.5 GHz and below one aW of power can be abstracted from the beam without degrading its quality. After frequency down-conversion to a few kHz, a narrow bandwidth detection performed by lock-in amplifiers separates them from noise. A maximum sample rate of 9 Hz and a resolution of one tenth of a millimeter could be achieved. The position signals have to be normalized to the beam current which is monitored by another dedicated resonator. The measurement precision down to a few pA allows for the accelerator extraction mechanism to be controlled by a feedback loop in order to obtain the respective requested current. (orig.)

  3. Development of an S-band cavity-type beam position monitor for a high power THz free-electron laser

    Science.gov (United States)

    Noh, Seon Yeong; Kim, Eun-San; Hwang, Ji-Gwang; Heo, A.; won Jang, Si; Vinokurov, Nikolay A.; Jeong, Young UK; Hee Park, Seong; Jang, Kyu-Ha

    2015-01-01

    A cavity-type beam position monitor (BPM) has been developed for a compact terahertz (THz) free-electron laser (FEL) system and ultra-short pulsed electron Linac system at the Korea Atomic Energy Research Institute (KAERI). Compared with other types of BPMs, the cavity-type BPM has higher sensitivity and faster response time even at low charge levels. When electron beam passes through the cavity-type BPM, it excites the dipole mode of the cavity of which amplitude depends linearly on the beam offset from the center of the cavity. Signals from the BPM were measured as a function of the beam offset by using an oscilloscope. The microtron accelerator for the KAERI THz FEL produces the electron beam with an energy of 6.5 MeV and pulse length of 5 μs with a micropulse of 10-20 ps at the frequency of 2.801 GHz. The macropulse beam current is 40 mA. Because the microtron provides multi-bunch system, output signal would be the superposition of each single bunch. So high output signal can be obtained from superposition of each single bunch. The designed position resolution of the cavity-type BPM in multi-bunch is submicron. Our cavity-type BPM is made of aluminum and vacuum can be maintained by indium sealing without brazing process, resulting in easy modification and cost saving. The resonance frequency of the cavity-type BPM is 2.803 GHz and the cavity-type BPM dimensions are 200 × 220 mm (length × height) with a pipe diameter of 38 mm. The measured position sensitivity was 6.19 (mV/mm)/mA and the measured isolation between the X and Y axis was -39 dB. By measuring the thermal noise of system, position resolution of the cavity-type BPM was estimated to be less than 1 μm. In this article, we present the test results of the S-band cavity-type BPM and prove the feasibility of the beam position measurement with high resolution using this device.

  4. Development of an S-band cavity-type beam position monitor for a high power THz free-electron laser

    Energy Technology Data Exchange (ETDEWEB)

    Noh, Seon Yeong; Kim, Eun-San, E-mail: eskim1@knu.ac.kr; Hwang, Ji-Gwang; Heo, A.; Won, Jang Si [Department of Physics, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Vinokurov, Nikolay A.; Jeong, Young UK, E-mail: yujung@kaeri.re.kr; Hee Park, Seong; Jang, Kyu-Ha [WCI Center for Quantum-Beam-based Radiation Research, Korea Atomic Energy Research Institute, 989-111 Daedeok-Daero, Yuseong-gu, Daejeon (Korea, Republic of)

    2015-01-15

    A cavity-type beam position monitor (BPM) has been developed for a compact terahertz (THz) free-electron laser (FEL) system and ultra-short pulsed electron Linac system at the Korea Atomic Energy Research Institute (KAERI). Compared with other types of BPMs, the cavity-type BPM has higher sensitivity and faster response time even at low charge levels. When electron beam passes through the cavity-type BPM, it excites the dipole mode of the cavity of which amplitude depends linearly on the beam offset from the center of the cavity. Signals from the BPM were measured as a function of the beam offset by using an oscilloscope. The microtron accelerator for the KAERI THz FEL produces the electron beam with an energy of 6.5 MeV and pulse length of 5 μs with a micropulse of 10-20 ps at the frequency of 2.801 GHz. The macropulse beam current is 40 mA. Because the microtron provides multi-bunch system, output signal would be the superposition of each single bunch. So high output signal can be obtained from superposition of each single bunch. The designed position resolution of the cavity-type BPM in multi-bunch is submicron. Our cavity-type BPM is made of aluminum and vacuum can be maintained by indium sealing without brazing process, resulting in easy modification and cost saving. The resonance frequency of the cavity-type BPM is 2.803 GHz and the cavity-type BPM dimensions are 200 × 220 mm (length × height) with a pipe diameter of 38 mm. The measured position sensitivity was 6.19 (mV/mm)/mA and the measured isolation between the X and Y axis was −39 dB. By measuring the thermal noise of system, position resolution of the cavity-type BPM was estimated to be less than 1 μm. In this article, we present the test results of the S-band cavity-type BPM and prove the feasibility of the beam position measurement with high resolution using this device.

  5. Analysis of the positive or negative lateral shift of the reflected beam in Otto configuration under grazing incidence

    Institute of Scientific and Technical Information of China (English)

    Haichun Zhou; Chunfang Li; Xi Chen

    2008-01-01

    We investigate the lateral shift of a TM-polarized light beam reflected from Otto configuration under grazing incidence. It is found that the lateral shift is strongly dependent on the thickness of the air-gap layer. By employing the pole-null representation, we demonstrate that the lateral shift is closely related to the null of the reflection function. The numerical simulations for a Gaussian beam are performed to demonstrate the validity of our theoretical analysis.

  6. DESIGN AND INITIAL RESULTS OF A TURN-BY-TURN BEAM POSITION MONITORING SYSTEM FOR MULTIPLE BUNCH OPERATION OF THE ATF DAMPING RING

    CERN Document Server

    Christian, G B; Bett, D R; Burrows, P N; Davis, M R; Gerbershagen, A; Perry, C; Constance, B; Resta-Lopez, J

    2011-01-01

    An FPGA-based monitoring system has been developed to study multi-bunch beam instabilities in the damping ring (DR) of the KEK Accelerator Test Facility (ATF), utilising a stripline beam position monitor (BPM) and existing BPM processor hardware. The system is designed to record the horizontal and/or vertical positions of up to three bunches in the DR in single-bunch multi-train mode or the head bunch of up to three trains in multi-bunch mode, with a bunch spacing of 5.6 ns. The FPGA firmware and data acquisition software were modified to record turn-by-turn data for up to six channels and 1–3 bunches in the DR. An overview of the system and initial results will be presented.

  7. Development of a Propagating Millimeter-Wave Beam Position and Profile Monitor in the Oversize Corrugated Waveguide Used in an ECRH System

    Science.gov (United States)

    Shimozuma, Takashi; Kobayashi, Sakuji; Ito, Satoshi; Ito, Yasuhiko; Kubo, Shin; Yoshimura, Yasuo; Nishiura, Masaki; Igami, Hiroe; Takahashi, Hiromi; Mizuno, Yoshinori; Okada, Kohta; Mutoh, Takashi

    2016-01-01

    In a high-power electron cyclotron resonance heating (ECRH) system for plasma heating, a long-distance and low-loss transmission system of the millimeter wave is required. A real-time monitor of the millimeter-wave beam position and its intensity profile, which can be used in a high-power, evacuated, and cooled transmission line, is proposed, designed, manufactured, and tested. The beam-position and profile monitor (BPM) consists of a reflector, Peltier-device array, and a heat-sink, which is installed in the reflector-plate of a miterbend. The BPM was tested using both simulated electric heater power and high-power gyrotron output power. The profile obtained from the monitor using the gyrotron output was well agreed with the burn patter on a thermal sensitive paper. Methods of data analysis and mode-content analysis of a propagating millimeter-wave in the corrugated waveguide are proposed.

  8. Influence of laser beam's image-plane position on geometry of through-holes in percussion-drilled glass using excimer laser

    OpenAIRE

    Petkovšek, Rok; Babnik, Aleš; Možina, Janez

    2015-01-01

    We study the influence of a laser beam's image-plane position relative to the processed surface for the deep-hole, laser-microdrilling of soda-lime glass with an excimer 308-nm laser and mask-projection technique. It is demonstrated that the image-plane position has a significant influence on the holes tapering and final depth. Holes with exit diameters up to 10 times smaller than the mask-image diameter are produced in the case of perforation during the appropriate process phase determined b...

  9. Cone Beam Computed Tomographic Analyses of the Position and Course of the Mandibular Canal: Relevance to the Sagittal Split Ramus Osteotomy

    Directory of Open Access Journals (Sweden)

    Ahmet Ercan Sekerci

    2014-01-01

    Full Text Available Purpose. The aim of this study was to document the position and course of the mandibular canal through the region of the mandibular angle and body in dental patients, using cone beam computed tomographic imaging. Methods. The position and course of the mandibular canal from the region of the third molar to the first molar were measured at five specific locations in the same plane: at three different positions just between the first and second molars; between the second and third molars; and just distal to the third molar. Results. The study sample was composed of 500 hemimandibles from 250 dental patients with a mean age of 26.32. Significant differences were found between genders, distances, and positions. B decreased significantly from the anterior positions to the posterior positions in both females and males. The mean values of S and CB increased significantly from the posterior positions to the anterior positions in both females and males. Conclusion. Because the sagittal split ramus osteotomy is a technically difficult procedure, we hope that the findings of the present study will help the surgeon in choosing the safest surgical technique for the treatment of mandibular deformities.

  10. Linearity of patient positioning detection. A phantom study of skin markers, cone beam computed tomography, and 3D ultrasound

    Energy Technology Data Exchange (ETDEWEB)

    Ballhausen, Hendrik; Hieber, Sheila; Li, Minglun; Belka, Claus; Reiner, Michael [University Hospital of LMU, Department of Radiation Oncology, Munich (Germany); Parodi, Katia [Ludwig-Maximilian-University, Department of Experimental Physics - Medical Physics, Munich (Germany)

    2015-05-01

    Three-dimensional ultrasound (3D-US) is a modality complementary to kilovoltage cone beam computed tomography (kV-CBCT) and skin markers for patient positioning detection. This study compares the linearity of evaluations based on measurements using a modern 3D-US system (Elekta Clarity {sup registered}; Elekta, Stockholm, Sweden), a kV-CBCT system (Elekta iView {sup registered}), and skin markers. An investigator deliberately displaced a multimodal phantom by up to ± 30 mm along different axes. The following data points were acquired: 27 along the lateral axis, 29 along the longitudinal axis, 27 along the vertical axis, and 27 along the space diagonal. At each of these 110 positions, the displacements according to skin' markers were recorded and scans were performed using both 3D-US and kV-CBCT. Shifts were detected by matching bony anatomy or soft tissue density to a reference planning CT in the case of kV-CBCT and for 3D-US, by matching ultrasound volume data to a reference planning volume. A consensus value was calculated from the average of the four modalities. With respect to this consensus value, the linearity (offset and regression coefficient, i.e., slope), average offset, systematic error, and random error of all four modalities were calculated for each axis. Linearity was similar for all four modalities, with regression coefficients between 0.994 and 1.012, and all offsets below 1 mm. The systematic errors of skin markers and 3D-US were higher than for kV-CBCT, but random errors were similar. In particular, 3D-US demonstrated an average offset of 0.36 mm to the right, 0.08 mm inferiorly, and 0.15 mm anteriorly; the systematic error was 0.36 mm laterally, 0.35 mm longitudinally, and 0.22 mm vertically; the random error was 0.15 mm laterally, 0.30 mm longitudinally, and 0.12 mm vertically. A total of 109 out of 110 (99 %) 3D-US measurements were within 1 mm of the consensus value on either axis. The linearity of 3D-US was no worse than that of skin

  11. Determination of the Virtual Source Position for the Electron Beams of a Varian Clinac 18 Linear Accelerator: a comparison of experiment methods

    International Nuclear Information System (INIS)

    The dosimetric characteristics of clinical electron beams,generated by medical linear accelerators,depend on the multiple scattering and energy losses in the scattering foil,monitor ion chambers,monitor assembly, collimator jaws and electron applicators.For the majority of clinical situations, it's appropriate to suppose that the diverging broad beam of electrons originates from a virtual point source.The ICRU defines the virtual point source as a source which when placed in vacuum at some distance Svirt ,that lies away from the scattering foil,will produce electrons which obey the inverse square law,and a mean-square angular spread θ2virt. A precise knowledge of the virtual source position is important for radiation dosimetry and treatment planning with clinical electron beams.For example,when a different air-gap from the originally planned,between the applicator and the patient skin is required,or when body inhomogeneities are present.Although the virtual source positions for our Clinac 18 were first determined in 1989, it was necessary to review the subject,due to the recent replacement of the electron gun and the aging conditions of the accelerator and its electron applicators.In addition,we extended the measurements to the 18 MeV electron mode,that were not available at that time

  12. Effect of Object Position in Cone Beam Computed Tomography Field of View for Detection of Root Fractures in Teeth with Intra-Canal Posts

    Directory of Open Access Journals (Sweden)

    Valizadeh

    2015-10-01

    Full Text Available Background Vertical root fracture (VRF is a common problem in endodontically treated teeth. Due to its poor prognosis, a reliable technique must be used to make an accurate diagnosis. Cone beam computed tomography (CBCT has been recently introduced for maxillofacial imaging. Despite the high diagnostic value of this method, metal artifacts resulting from intra-canal posts still make the detection of VRFs challenging. Objectives This study aimed to assess the effect of object position in the field of view (FOV of CBCT on detection of VRFs in teeth with intra-canal posts. Materials and Methods The crowns of 60 extracted premolar teeth were cut at the level of cementoenamel junction (CEJ. Root canals were filled with gutta-percha and filling of the coronal 2/3 of the root canals was subsequently removed to fabricate intra-canal cast posts. The teeth were randomly divided into two groups of 30. Fracture was induced in group one using an Instron machine. Group two was considered as the control group with no fracture. All teeth were then randomly positioned and scanned in five different positions starting at the center of the FOV as well as right, left anterior and posterior relative to the center (3, 9, 12, and 6 O’clock via the New Tom VGI CBCT unit. Two observers evaluated images for VRFs. Sensitivity and specificity of fracture diagnosis in each position was calculated in comparison with the gold standard. Wilcoxon test was used for data analysis. Results Considering deterministic and probabilistic diagnostic parameters, probabilistic sensitivity was similar in all positions; but probabilistic specificity of the center position (65.1% was significantly higher than that of 6 and 12 O’clock positions. Considering the deterministic diagnostic parameters, the overall sensitivity and specificity values decreased in all positions in FOV, but sensitivity of the center position of FOV was significantly higher than that of other positions; specificity

  13. A method for simultaneous linear optics and coupling correction for storage rings with turn-by-turn beam position monitor data

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Xi [Brookhaven National Lab. (BNL), Upton, NY (United States); Huang, Xiaobiao [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2016-08-01

    We propose a method to simultaneously correct linear optics errors and linear coupling for storage rings using turn-by-turn (TbT) beam position monitor (BPM) data. The independent component analysis (ICA) method is used to isolate the betatron normal modes from the measured TbT BPM data. The betatron amplitudes and phase advances of the projections of the normal modes on the horizontal and vertical planes are then extracted, which, combined with dispersion measurement, are used to fit the lattice model. Furthermore, the fitting results are used for lattice correction. Our method has been successfully demonstrated on the NSLS-II storage ring.

  14. A method for simultaneous linear optics and coupling correction for storage rings with turn-by-turn beam position monitor data

    Science.gov (United States)

    Yang, Xi; Huang, Xiaobiao

    2016-08-01

    We propose a method to simultaneously correct linear optics errors and linear coupling for storage rings using turn-by-turn (TbT) beam position monitor (BPM) data. The independent component analysis (ICA) method is used to isolate the betatron normal modes from the measured TbT BPM data. The betatron amplitudes and phase advances of the projections of the normal modes on the horizontal and vertical planes are then extracted, which, combined with dispersion measurement, are used to fit the lattice model. The fitting results are used for lattice correction. The method has been successfully demonstrated on the NSLS-II storage ring.

  15. Beam collimator

    CERN Multimedia

    1977-01-01

    A four-block collimator installed on a control table for positioning the alignment reference marks. Designed for use with SPS secondary beams, the collimator operates under vacuum conditions. See Annual Report 1976 p. 121 and photo 7701014.

  16. GEANT4 simulation diagram showing the architecture of the ATLAS test line: the detectors are positioned to receive the beam from the SPS. A muon particle which enters the magnet and crosses all detectors is shown (blue line).

    CERN Multimedia

    2004-01-01

    GEANT4 simulation diagram showing the architecture of the ATLAS test line: the detectors are positioned to receive the beam from the SPS. A muon particle which enters the magnet and crosses all detectors is shown (blue line).

  17. Evaluation for Basic Image Qualities Dependence on the Position in XYZ Directions and Acquisition Parameters of the Cone Beam CT for Angiography System with Flat Panel Detector.

    Science.gov (United States)

    Tsuda, Norisato; Mitsui, Kota; Oda, Shinichiro

    2016-08-01

    The purpose of this study was to investigate the effect of the position in XYZ directions and acquisition parameters on the basic image qualities of for cone beam computed tomography (CBCT) in an angiography system with flat panel detector. The resolution property (modulation transfer function: MTF) and the noise property (Wiener spectrum: WS) of CBCT images in X-Y plane were measured with different acquisition parameters (scan matrix number and projection number) and the effect of the position in XYZ directions. The MTFs with 1024×1024 matrix were higher than those of 512×512 matrix and decreased in the peripheral areas due to the reduction of projection number. The highest and the lowest MTFs were measured at the X-ray tube side and on the detector side of the position in X-Y plane, respectively. The WS-doubled projection number showed about 50% lesser noise level. There were differences in the Wiener spectra (WS) at the position in XYZ directions. We conclude that the resolution and the noise property of CBCT image in X-Y plane showed dependences on the position in XYZ directions and acquisition parameters of the CBCT. PMID:27546079

  18. Smart x-ray beam position monitor system using artificial intelligence methods for the advanced photon source insertion-device beamlines

    International Nuclear Information System (INIS)

    At the Advanced Photon Source (APS), each insertion device (ID) beamline front-end has two XBPMs to monitor the X-ray beam position for both that vertical and horizontal directions. Performance challenges for a conventional photoemission type X-ray beam position monitor (XBPM) during operations are contamination of the signal from the neighboring bending magnet sources and the sensitivity of the XBPM to the insertion device (ID) gap variations. Problems are exacerbated because users change the ID gap during their operations, and hence the percentage level of the contamination in the front end XBPM signals varies. A smart XBPM system with a high speed digital signal processor has been built at the Advanced Photon Source for the ID beamline front ends. The new version of the software, which uses an artificial intelligence method, provides a self learning and self-calibration capability to the smart XBPM system. The structure of and recent test results with the system are presented in this paper

  19. Extraction of radioactive positive ions across the surface of superfluid helium : A new method to produce cold radioactive nuclear beams

    NARCIS (Netherlands)

    Huang, WX; Dendooven, P; Gloos, K; Takahashi, N; Pekola, JP; Aysto, J

    2003-01-01

    Alpha-decay recoils Rn-219 were stopped in superfluid helium and positive ions were extracted by electric field into the vapour phase. This first quantitative observation of extraction was successfully conducted using highly sensitive radioactivity detection. The efficiency for extraction across the

  20. Beam-Beam Effects

    CERN Document Server

    Herr, W

    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.

  1. Implication of spot position error on plan quality and patient safety in pencil-beam-scanning proton therapy

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Juan; Beltran, Chris J., E-mail: beltran.chris@mayo.edu; Herman, Michael G. [Division of Medical Physics, Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota 55905 (United States)

    2014-08-15

    Purpose: To quantitatively and systematically assess dosimetric effects induced by spot positioning error as a function of spot spacing (SS) on intensity-modulated proton therapy (IMPT) plan quality and to facilitate evaluation of safety tolerance limits on spot position. Methods: Spot position errors (PE) ranging from 1 to 2 mm were simulated. Simple plans were created on a water phantom, and IMPT plans were calculated on two pediatric patients with a brain tumor of 28 and 3 cc, respectively, using a commercial planning system. For the phantom, a uniform dose was delivered to targets located at different depths from 10 to 20 cm with various field sizes from 2{sup 2} to 15{sup 2} cm{sup 2}. Two nominal spot sizes, 4.0 and 6.6 mm of 1 σ in water at isocenter, were used for treatment planning. The SS ranged from 0.5 σ to 1.5 σ, which is 2–6 mm for the small spot size and 3.3–9.9 mm for the large spot size. Various perturbation scenarios of a single spot error and systematic and random multiple spot errors were studied. To quantify the dosimetric effects, percent dose error (PDE) depth profiles and the value of percent dose error at the maximum dose difference (PDE [ΔDmax]) were used for evaluation. Results: A pair of hot and cold spots was created per spot shift. PDE[ΔDmax] is found to be a complex function of PE, SS, spot size, depth, and global spot distribution that can be well defined in simple models. For volumetric targets, the PDE [ΔDmax] is not noticeably affected by the change of field size or target volume within the studied ranges. In general, reducing SS decreased the dose error. For the facility studied, given a single spot error with a PE of 1.2 mm and for both spot sizes, a SS of 1σ resulted in a 2% maximum dose error; a SS larger than 1.25 σ substantially increased the dose error and its sensitivity to PE. A similar trend was observed in multiple spot errors (both systematic and random errors). Systematic PE can lead to noticeable hot

  2. Direct patterning of high density sub-15 nm gold dot arrays using ultrahigh contrast electron beam lithography process on positive tone resist

    International Nuclear Information System (INIS)

    Ultrahigh density nanostructure arrays with controlled size and position have promised a variety of potential applications. However, their practical realization is often hindered by the amount of resources required for large-scale fabrication. Using an ultrahigh contrast electron beam lithography process, we show ultrahigh resolution and high aspect ratio patterning capability which can be done at an exposure dose lower than 100 μC cm−2. In particular, the high aspect ratio of dot arrays on 110 nm thick resist is confirmed by a standard lift-off process of 20 nm thick gold nanodots at sub-15 nm feature size and 40 nm pitch. The smallest gold nanodot size from our experiment is ∼11 nm. (paper)

  3. Prostate positioning using cone-beam computer tomography based on manual soft-tissue registration. Interobserver agreement between radiation oncologists and therapists

    Energy Technology Data Exchange (ETDEWEB)

    Jereczek-Fossa, B.A.; Pobbiati, C.; Fanti, P. [European Institute of Oncology, Department of Radiation Oncology, Milan (Italy); University of Milan, Milan (Italy); Santoro, L. [European Institute of Oncology, Department of Epidemiology and Biostatistics, Milan (Italy); Fodor, C.; Zerini, D. [European Institute of Oncology, Department of Radiation Oncology, Milan (Italy); Vigorito, S. [European Institute of Oncology, Department of Medical Physics, Milan (Italy); Baroni, G. [Politecnico di Milano, Department of Electronics Information and Bioengineering, Milan (Italy); De Cobelli, O. [European Institute of Oncology, Department of Urology, Milan (Italy); University of Milan, Milan (Italy); Orecchia, R. [European Institute of Oncology, Department of Radiation Oncology, Milan (Italy); National Center for Oncological Hadrontherapy (CNAO) Foundation, Pavia (Italy); University of Milan, Milan (Italy)

    2014-01-15

    To check the interobserver agreement between radiation oncologists and therapists (RTT) using an on- and off-line cone-beam computer tomography (CBCT) protocol for setup verification in the radiotherapy of prostate cancer. The CBCT data from six prostate cancer patients treated with hypofractionated intensity-modulated radiotherapy (IMRT) were independently reviewed off-line by four observers (one radiation oncologist, one junior and two senior RTTs) and benchmarked with on-line CBCT positioning performed by a radiation oncologist immediately prior to treatment. CBCT positioning was based on manual soft-tissue registration. Agreement between observers was evaluated using weighted Cohen's kappa statistics. In total, 152 CBCT-based prostate positioning procedures were reviewed by each observer. The mean (± standard deviation) of the differences between off- and on-line CBCT-simCT registration translations along the three directions (antero-posterior, latero-lateral and cranio-caudal) and rotation around the antero-posterior axis were - 0.7 (3.6) mm, 1.9 (2.7) mm, 0.9 (3.6) mm and - 1.8 (5.0) degrees, respectively. Satisfactory interobserver agreement was found, being substantial (weighted kappa > 0.6) in 10 of 16 comparisons and moderate (0.41-0.60) in the remaining six comparisons. CBCT interpretation performed by RTTs is comparable to that of radiation oncologists. Our study might be helpful in the quality assurance of radiotherapy and the optimization of competencies. Further investigation should include larger sample sizes, a greater number of observers and validated methodology in order to assess interobserver variability and its impact on high-precision prostate cancer IGRT. In the future, it should enable the wider implementation of complex and evolving radiotherapy technologies. (orig.)

  4. Experiments for possible hydroacoustic discrimination of free-swimming juvenile gadoid fish by analysis of broadband pulse spectra as well as 3D fish position form video images and split beam acoustics

    DEFF Research Database (Denmark)

    Lundgren, Bo; Nielsen, J. Rasmus

    2002-01-01

    Measurements were made of the broad-bandwidth (80–220 kHz) acoustic backscattering from free-swimming juvenile gadoids at various orientations and positions in an acoustic beam, under controlled conditions. The experimental apparatus consisted of a stereo-video camera system, a broad-bandwidth ec......Measurements were made of the broad-bandwidth (80–220 kHz) acoustic backscattering from free-swimming juvenile gadoids at various orientations and positions in an acoustic beam, under controlled conditions. The experimental apparatus consisted of a stereo-video camera system, a broad...

  5. Reconstruction of brachytherapy seed positions and orientations from cone-beam CT x-ray projections via a novel iterative forward projection matching method

    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)

    2011-01-15

    Purpose: To generalize and experimentally validate a novel algorithm for reconstructing the 3D pose (position and orientation) of implanted brachytherapy seeds from a set of a few measured 2D cone-beam CT (CBCT) x-ray projections. Methods: The iterative forward projection matching (IFPM) algorithm was generalized to reconstruct the 3D pose, as well as the centroid, of brachytherapy seeds from three to ten measured 2D projections. The gIFPM algorithm finds the set of seed poses that minimizes the sum-of-squared-difference of the pixel-by-pixel intensities between computed and measured autosegmented radiographic projections of the implant. Numerical simulations of clinically realistic brachytherapy seed configurations were performed to demonstrate the proof of principle. An in-house machined brachytherapy phantom, which supports precise specification of seed position and orientation at known values for simulated implant geometries, was used to experimentally validate this algorithm. The phantom was scanned on an ACUITY CBCT digital simulator over a full 660 sinogram projections. Three to ten x-ray images were selected from the full set of CBCT sinogram projections and postprocessed to create binary seed-only images. Results: In the numerical simulations, seed reconstruction position and orientation errors were approximately 0.6 mm and 5 deg., respectively. The physical phantom measurements demonstrated an absolute positional accuracy of (0.78{+-}0.57) mm or less. The {theta} and {phi} angle errors were found to be (5.7{+-}4.9) deg. and (6.0{+-}4.1) deg., respectively, or less when using three projections; with six projections, results were slightly better. The mean registration error was better than 1 mm/6 deg. compared to the measured seed projections. Each test trial converged in 10-20 iterations with computation time of 12-18 min/iteration on a 1 GHz processor. Conclusions: This work describes a novel, accurate, and completely automatic method for reconstructing

  6. Target motion variability and on-line positioning accuracy during external-beam radiation therapy of prostate cancer with an endorectal balloon device

    Energy Technology Data Exchange (ETDEWEB)

    El-Bassiouni, M. [Radiation Oncology, Zurich Univ. Hospital, Univ. of Zurich (Switzerland); Dept. of Clinical Oncology (NEMROCK), Cairo Univ. Hospitals, Cairo (Egypt); Davis, J.B.; Studer, G.M.; Luetolf, U.M.; Ciernik, I.F. [Radiation Oncology, Zurich Univ. Hospital, Univ. of Zurich (Switzerland); El-Attar, I. [Dept. of Epidemiology and Statistics, National Cancer Inst. (NCI), Univ. of Cairo (Egypt)

    2006-09-15

    Purpose: to prospectively define the setup error and the interfraction prostate localization accuracy of the planning target volume (PTV) in the presence of an endorectal balloon (ERB) device. Patients and methods: weekly portal images (PIs) of 15 patients undergoing external-beam radiotherapy were analyzed. Displacements of the isocenter and the center of the ERB were measured. The setup and target motion variability were assessed with regard to the position variability of the ERB. Results: the setup error was random and target motion variability was largest in the craniocaudal direction. The mean displacement of the isocenter was 2.1 mm ({+-} 1.2 mm SD [standard deviation]), 2.4 mm ({+-} 2.2 mm SD), and 3.8 mm ({+-} 4.0 mm SD) in the left-right, craniocaudal, and anteroposterior directions, respectively (p = 0.1). The mean displacement of the ERB was 2.0 mm ({+-} 1.4 mm SD), 4.1 mm ({+-} 2.0 mm SD), and 3.8 mm ({+-} 3.3 mm SD; p = 0.03). Setup margin and internal margin contributed equally to the PTV margin. Cumulative placement insecurity of the field and the ERB together was 4.0 mm ({+-} 2.1 mm SD) laterally, 6.4 mm ({+-} 2.5 mm SD) craniocaudally, and 7.7 mm ({+-} 7.0 mm SD) anteroposteriorly. The 95% CIs (confidence intervals) were 2.9-5.2 mm, 5.1-7.8 mm, and 3.8-11.5 mm. In 35% of cases, the estimation of the dorsal margin exceeded 1 cm. Conclusion: margin estimate dorsally may exceed 1 cm and on-line position verification with an ERB cannot be recommended for dose escalation > 70 Gy. (orig.)

  7. Feasibility of patient dose reduction based on various noise suppression filters for cone-beam computed tomography in an image-guided patient positioning system

    Science.gov (United States)

    Kamezawa, Hidemi; Arimura, Hidetaka; Shirieda, Katsutoshi; Kameda, Noboru; Ohki, Masafumi

    2016-05-01

    We investigated the feasibility of patient dose reduction based on six noise suppression filters for cone-beam computed tomography (CBCT) in an image-guided patient positioning (IGPP) system. A midpoint dose was employed as a patient dose index. First, a reference dose (RD) and low-dose (LD)-CBCT images were acquired with a reference dose and various low doses. Second, an automated rigid registration was performed for three axis translations to estimate patient setup errors between a planning CT image and the LD-CBCT images processed by six noise suppression filters (averaging filter, median filter, Gaussian filter, edge-preserving smoothing filter, bilateral filter, and adaptive partial median filter (AMF)). Third, residual errors representing the patient positioning accuracy were calculated as Euclidean distances between the setup error vectors estimated using the LD-CBCT and RD-CBCT images. Finally, the residual errors as a function of the patient dose index were estimated for LD-CBCT images processed by six noise suppression filters, and then the patient dose indices for the filtered LD-CBCT images were obtained at the same residual error as the RD-CBCT image. This approach was applied to an anthropomorphic phantom and four cancer patients. The patient dose for the LD-CBCT images was reduced to 19% of that for the RD-CBCT image for the phantom by using AMF, while keeping a same residual error of 0.47 mm as the RD-CBCT image by applying the noise suppression filters to the LD-CBCT images. The average patient dose was reduced to 31.1% for prostate cancer patients, and it was reduced to 82.5% for a lung cancer patient by applying the AMF. These preliminary results suggested that the proposed approach based on noise suppression filters could decrease the patient dose in IGPP systems.

  8. Positioning variation analysis using Cone Beam Computed Tomography volumetric images; Analise das variacoes de posicionamento utilizando imagens volumetricas de Tomografia Computadorizada de Feixe Conico

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Camila T.; Fontana, Thiago S.; Habitzreuter, Angela B.; Santos, Gabriela R.; Rodrigues, Laura N., E-mail: camila_fmedica@hotmail.com [Instituto do Cancer do Estado de Sao Paulo(ICESP), Sao Paulo, SP (Brazil). Servico de Radioterapia

    2013-12-15

    Radiotherapy is one of the main treatment modalities of malignancies, either associated with other techniques or not. The successful use of radiation depends on several factors, such as the choice of treatment technique, dosimetric accuracy and geometric precision. The movement of internal organs plays a role quite significant in the calculation of setup margins, but during treatment, the most important variation is the patient’s positioning error. This study evaluated the geometric accuracy in positioning patients with anal canal, prostate, and head and neck cancer, who were treated at ICESP. Cone Beam Computed Tomography (CBCT) images of 40 patients were used, totalizing 224 images. For every CBCT image, the displacement was calculated through the fusion between the images acquired before the treatment and CT images obtained in the simulation.The average deviation was 0.24±0.10 cm to the left-right direction, 0.21±0.12 cm in the anterior-posterior and 0.30±0.18 cm in the superior-inferior direction for cases of anal canal; 0.20±0.10 cm in the left-right, 0.20±0.10 cm in the anterior-posterior and 0.23±0.11 cm in superior-inferior direction for prostate treatments; and 0.11±0.07 cm in the left-right, 0.13±0.06 cm in the anterior-posterior and 0.15±0.10 cm in superior-inferior direction for the treatment of head and neck. The results found were within the predicted PTV margins used at the Institution. (author)

  9. Feasibility of patient dose reduction based on various noise suppression filters for cone-beam computed tomography in an image-guided patient positioning system.

    Science.gov (United States)

    Kamezawa, Hidemi; Arimura, Hidetaka; Shirieda, Katsutoshi; Kameda, Noboru; Ohki, Masafumi

    2016-05-01

    We investigated the feasibility of patient dose reduction based on six noise suppression filters for cone-beam computed tomography (CBCT) in an image-guided patient positioning (IGPP) system. A midpoint dose was employed as a patient dose index. First, a reference dose (RD) and low-dose (LD)-CBCT images were acquired with a reference dose and various low doses. Second, an automated rigid registration was performed for three axis translations to estimate patient setup errors between a planning CT image and the LD-CBCT images processed by six noise suppression filters (averaging filter, median filter, Gaussian filter, edge-preserving smoothing filter, bilateral filter, and adaptive partial median filter (AMF)). Third, residual errors representing the patient positioning accuracy were calculated as Euclidean distances between the setup error vectors estimated using the LD-CBCT and RD-CBCT images. Finally, the residual errors as a function of the patient dose index were estimated for LD-CBCT images processed by six noise suppression filters, and then the patient dose indices for the filtered LD-CBCT images were obtained at the same residual error as the RD-CBCT image. This approach was applied to an anthropomorphic phantom and four cancer patients. The patient dose for the LD-CBCT images was reduced to 19% of that for the RD-CBCT image for the phantom by using AMF, while keeping a same residual error of 0.47 mm as the RD-CBCT image by applying the noise suppression filters to the LD-CBCT images. The average patient dose was reduced to 31.1% for prostate cancer patients, and it was reduced to 82.5% for a lung cancer patient by applying the AMF. These preliminary results suggested that the proposed approach based on noise suppression filters could decrease the patient dose in IGPP systems. PMID:27065312

  10. Beam-beam effects

    Energy Technology Data Exchange (ETDEWEB)

    Zholents, A.

    1994-12-01

    The term beam-beam effects is usually used to designate different phenomena associated with interactions of counter-rotating beams in storage rings. Typically, the authors speak about beam-beam effects when such interactions lead to an increase of the beam core size or to a reduction of the beam lifetime or to a growth of particle`s population in the beam halo and a correspondent increase of the background. Although observations of beam-beam effects are very similar in most storage rings, it is very likely that every particular case is largely unique and machine-dependent. This constitutes one of the problems in studying the beam-beam effects, because the experimental results are often obtained without characterizing a machine at the time of the experiment. Such machine parameters as a dynamic aperture, tune dependencies on amplitude of particle oscillations and energy, betatron phase advance between the interaction points and some others are not well known, thus making later analysis uncertain. The authors begin their discussion with demonstrations that beam-beam effects are closely related to non linear resonances. Then, they will show that a non linearity of the space charge field is responsible for the excitation of these resonances. After that, they will consider how beam-beam effects could be intensified by machine imperfections. Then, they will discuss a leading mechanism for the formation of the beam halo and will describe a new technique for beam tails and lifetime simulations. They will finish with a brief discussion of the coherent beam-beam effects.

  11. Beam position monitor system design in 100MeV linac%100MeV直线加速器束流位置探测器系统设计

    Institute of Scientific and Technical Information of China (English)

    殷重先; 叶恺容; 周伟民

    2007-01-01

    100MeV直线加速器束流位置探测器系统包括BPM(Beam position monitor)、BPM前端电子学、基于束流的准直模块(Beam based calibration,BBC)、高频信号切换模块和AD模块.本文详细介绍了BPM前端电子学和数据采集系统设计.最后给出了在100MeV直线加速器中测试的BPM系统性能.

  12. PARTICLE BEAM TRACKING CIRCUIT

    Science.gov (United States)

    Anderson, O.A.

    1959-05-01

    >A particle-beam tracking and correcting circuit is described. Beam induction electrodes are placed on either side of the beam, and potentials induced by the beam are compared in a voltage comparator or discriminator. This comparison produces an error signal which modifies the fm curve at the voltage applied to the drift tube, thereby returning the orbit to the preferred position. The arrangement serves also to synchronize accelerating frequency and magnetic field growth. (T.R.H.)

  13. Literature in Focus Beta Beams: Neutrino Beams

    CERN Multimedia

    2009-01-01

    By Mats Lindroos (CERN) and Mauro Mezzetto (INFN Padova, Italy) Imperial Press, 2009 The beta-beam concept for the generation of electron neutrino beams was first proposed by Piero Zucchelli in 2002. The idea created quite a stir, challenging the idea that intense neutrino beams only could be produced from the decay of pions or muons in classical neutrino beams facilities or in future neutrino factories. The concept initially struggled to make an impact but the hard work by many machine physicists, phenomenologists and theoreticians over the last five years has won the beta-beam a well-earned position as one of the frontrunners for a possible future world laboratory for high intensity neutrino oscillation physics. This is the first complete monograph on the beta-beam concept. The book describes both technical aspects and experimental aspects of the beta-beam, providing students and scientists with an insight into the possibilities o...

  14. Multi-Beam Optical Tweezers

    DEFF Research Database (Denmark)

    2003-01-01

    A set of multi-beam electromagnetic tweezers is provided comprising a multi-beam generator for emission of a plurality of electromagnetic beams, at least some of the electromagnetic beams intersecting each other, or, having an individually controlled polarization whereby the position and/or angul...

  15. Measurement of defects on the wall by use of the inclination angle of laser slit beam and position tracking algorithm of camera

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young Hwan; Yoon, Ji Sup; Jung, Jae Hoo; Hong, Dong Hee; Park, Gee Yong

    2001-01-01

    In this paper, a method of measuring the size of defects on the wall and restructuring the defect image is proposed based on the estimation algorithm of a camera orientation which uses the declination angle of the line slit beam. To reconstruct the image, an algorithm of estimating the horizontally inclined angle of CCD camera is presented. This algorithm adopts a 3-dimensional coordinate transformation of the image plane where both the LASER beam and the original image of the defects exist. The estimation equation is obtained by using the information of the beam projected on the wall and the parameters of this equation are experimentally obtained. With this algorithm, the original image of the defect can be reconstructed into the image which is obtained by a camera normal to the wall. From the result of a series of experiment shows that the measuring accuracy of the defect is within 0.5% error bound of real defect size under 30 degree of the horizontally inclined angle. Also, the accuracy is deteriorates with the error rate of 1% for every 10 degree increase of the horizontally inclined angle. The estimation error increases in the range of 30{approx}50 degree due to the existence of dead zone of defect depth, and defect length can not be measured due to the disappearance of image data above 70 degree. In case of under water condition, the measuring accuracy is also influenced due to the changed field of view of both the camera and the laser slit beam caused by the refraction rate in the water. The proposed algorithm provides the method of reconstructing the image taken at any arbitrary camera orientation into the image which is obtained by a camera normal to the wall and thus it enables the accurate measurement of the defect lengths only by using a single camera and a laser slit beam.

  16. High-resolution, high-throughput, positive-tone patterning of poly(ethylene glycol by helium beam exposure through stencil masks.

    Directory of Open Access Journals (Sweden)

    Eliedonna E Cacao

    Full Text Available In this work, a collimated helium beam was used to activate a thiol-poly(ethylene glycol (SH-PEG monolayer on gold to selectively capture proteins in the exposed regions. Protein patterns were formed at high throughput by exposing a stencil mask placed in proximity to the PEG-coated surface to a broad beam of helium particles, followed by incubation in a protein solution. Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR spectra showed that SH-PEG molecules remain attached to gold after exposure to beam doses of 1.5-60 µC/cm(2 and incubation in PBS buffer for one hour, as evidenced by the presence of characteristic ether and methoxy peaks at 1120 cm(-1 and 2870 cm(-1, respectively. X-ray Photoelectron Spectroscopy (XPS spectra showed that increasing beam doses destroy ether (C-O bonds in PEG molecules as evidenced by the decrease in carbon C1s peak at 286.6 eV and increased alkyl (C-C signal at 284.6 eV. XPS spectra also demonstrated protein capture on beam-exposed PEG regions through the appearance of a nitrogen N1s peak at 400 eV and carbon C1s peak at 288 eV binding energies, while the unexposed PEG areas remained protein-free. The characteristic activities of avidin and horseradish peroxidase were preserved after attachment on beam-exposed regions. Protein patterns created using a 35 µm mesh mask were visualized by localized formation of insoluble diformazan precipitates by alkaline phosphatase conversion of its substrate bromochloroindoyl phosphate-nitroblue tetrazolium (BCIP-NBT and by avidin binding of biotinylated antibodies conjugated on 100 nm gold nanoparticles (AuNP. Patterns created using a mask with smaller 300 nm openings were detected by specific binding of 40 nm AuNP probes and by localized HRP-mediated deposition of silver nanoparticles. Corresponding BSA-passivated negative controls showed very few bound AuNP probes and little to no enzymatic formation of diformazan precipitates or silver

  17. WELD FORMATION CONTROL AT ELECTRON BEAM WELDING WITH BEAM OSCILLATIONS

    OpenAIRE

    Trushnikov, Dmitriy; Koleva, Elena; Mladenov, Georgy; Shcherbakov, A.

    2014-01-01

    Electron beam welding is used extensively to produce essential machine parts. The control of the basic beam parameters beam power or beam current at constant accelerating voltage, welding speed, current of focusing lens and distance between electron gun and welded sample surface is not enough to obtain at most of the regimes sound welds. Control of the focus position using analysis of the high frequency component of the current, collected by plasma, at periodic interactions on the beam (the o...

  18. Determination of the Waist Position of a Gaussian Beam by Bacteriorhodopsin Film%由细菌视紫红质测定高斯光束的束腰位置

    Institute of Scientific and Technical Information of China (English)

    陈桂英; 郭宗霞; 张春平; 田建国; Q.W.Song; Mingchien Huang

    2004-01-01

    Relation between transmitted intensity of bacteriorhodopsin(bR) film and the incident intensity was tested.A new method of determining waist position of a Gaussian beam passing an optical system was proposed by the nonlinear transmission of the bR film.The measured results are in agreement with the calculated results based on the parameters of the Guassian beam.%介绍并测量了细菌视紫红质(bR)的透过光强随入射光强的变化特性,并提出利用bR的非线性透过特性测定高斯光束的束腰位置,测量结果与利用已知的高斯光束参数所计算的结果相一致.

  19. KEKB beam instrumentation systems

    Science.gov (United States)

    Arinaga, M.; Flanagan, J.; Hiramatsu, S.; Ieiri, T.; Ikeda, H.; Ishii, H.; Kikutani, E.; Mimashi, T.; Mitsuhashi, T.; Mizuno, H.; Mori, K.; Tejima, M.; Tobiyama, M.

    2003-02-01

    For the stable high-luminosity operation and luminosity increase, the electron and positron storage rings of the KEK B-Factory (KEKB) is equipped with various beam instrumentations, which have been working well since the start of the commissioning in December, 1998. Details and performance of the beam-position monitor system based on the spectrum analysis using DSPs, the turn-by-turn BPM with four-dimensional function available for measurements of the individual bunch position, phase and intensity, the parametric beam-DCCTs designed so as to avoid the magnetic-core-selection problems for the parametric flux modulation, the bunch-by-bunch feedback system indispensable to suppress the strong multibunch instabilities in KEKB, the various optical beam diagnostic systems, such as synchrotron radiation interferometers for precise beam-size measurement, the tune meters, the bunch length monitors and the beam-loss monitors are described. Delicate machine tuning of KEKB is strongly supported by these instrumentations.

  20. 预制T梁钢筋定位安装与保护层控制技术%Prefabricated T beam reinforced positioning installation and control technology of protection layers

    Institute of Scientific and Technical Information of China (English)

    皮秦

    2012-01-01

    Combining with the reinforced construction examples of a section of prefabricated T beam of Yong-Ning highway,through the development of QC technology research activities,this paper researched the positioning installation technology of highway prefabricated T beam reinforced and control technology of protective layers,greatly improving the construction quality and efficiency of prefabricated T beam reinforcement,the experience and results obtained had very referential reference value for the future similar engineering construction.%结合永宁高速公路某标段预制T梁钢筋施工实例,通过开展QC技术攻关活动,研究改进了公路预制T梁钢筋定位安装工艺和保护层控制技术,大大提高了预制T梁钢筋施工质量和功效;所取得的经验和成果对今后类似工程施工非常有借鉴参考价值。

  1. Beam alignment system

    International Nuclear Information System (INIS)

    A patent is claimed for the invention of a beam alignment system. The aim of the invention is the obtention of an accurate monitoring of the beam position and direction. It is of great interest in the nuclear industry. The invention can be applied in an infrared laser beam for welding operations. An auxiliar radiation source is incorporated to the device. The system's configuration allows a simultaneous and separated utilisation of two beams. The description and the design of the proposed system are provided

  2. Measurements of aperture and beam lifetime using movable beam scrapers in Indus-2 electron storage ring

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Pradeep; Ghodke, A. D.; Karnewar, A. K.; Holikatti, A. C.; Yadav, S.; Puntambekar, T. A.; Singh, G. [Raja Ramanna Centre for Advanced Technology, Indore 452013 (India); Singh, P. [Bhabha Atomic Research Centre, Mumbai (India)

    2013-12-15

    In this paper, the measurements of vertical and horizontal aperture which are available for stable beam motion in Indus-2 at beam energy 2.5 GeV using movable beam scrapers are presented. These beam scrapers are installed in one of the long straight sections in the ring. With the movement of beam scrapers towards the beam centre, the beam lifetime is measured. The beam lifetime data obtained from the movement of vertical and horizontal beam scrapers are analyzed. The contribution of beam loss due to beam-gas scattering (vacuum lifetime) and electron-electron scattering within a beam bunch (Touschek lifetime) is separated from the measured beam lifetime at different positions of the beam scrapers. Vertical and horizontal beam sizes at scrapers location are estimated from the scraper movement towards the beam centre in quantum lifetime limit and their values closely agree with measured value obtained using X-ray diagnostic beamline.

  3. Measurements of aperture and beam lifetime using movable beam scrapers in Indus-2 electron storage ring.

    Science.gov (United States)

    Kumar, Pradeep; Ghodke, A D; Karnewar, A K; Holikatti, A C; Yadav, S; Puntambekar, T A; Singh, G; Singh, P

    2013-12-01

    In this paper, the measurements of vertical and horizontal aperture which are available for stable beam motion in Indus-2 at beam energy 2.5 GeV using movable beam scrapers are presented. These beam scrapers are installed in one of the long straight sections in the ring. With the movement of beam scrapers towards the beam centre, the beam lifetime is measured. The beam lifetime data obtained from the movement of vertical and horizontal beam scrapers are analyzed. The contribution of beam loss due to beam-gas scattering (vacuum lifetime) and electron-electron scattering within a beam bunch (Touschek lifetime) is separated from the measured beam lifetime at different positions of the beam scrapers. Vertical and horizontal beam sizes at scrapers location are estimated from the scraper movement towards the beam centre in quantum lifetime limit and their values closely agree with measured value obtained using X-ray diagnostic beamline.

  4. Assessing joint space and condylar position in the people with normal function of temporomandibular joint with cone-beam computed tomography

    Directory of Open Access Journals (Sweden)

    Zahra Dalili

    2012-01-01

    Conclusion: The assessment of joint spaces in right and left sides should be done independently. Overall, the measured joint spaces except Sjs are not different in two sexes. The data from this study could be a useful and comparable reference for the clinical assessment of condylar position in patients with normal functional joints.

  5. Bessel Beams

    OpenAIRE

    McDonald, Kirk T

    2000-01-01

    Scalar Bessel beams are derived both via the wave equation and via diffraction theory. While such beams have a group velocity that exceeds the speed of light, this is a manifestation of the "scissors paradox" of special relativty. The signal velocity of a modulated Bessel beam is less than the speed of light. Forms of Bessel beams that satisfy Maxwell's equations are also given.

  6. SU-E-P-54: Evaluation of the Accuracy and Precision of IGPS-O X-Ray Image-Guided Positioning System by Comparison with On-Board Imager Cone-Beam Computed Tomography

    International Nuclear Information System (INIS)

    Purpose: The purpose of this study is to assess the positioning accuracy and precision of IGPS-O system which is a novel radiographic kilo-voltage x-ray image-guided positioning system developed for clinical IGRT applications. Methods: IGPS-O x-ray image-guided positioning system consists of two oblique sets of radiographic kilo-voltage x-ray projecting and imaging devices which were equiped on the ground and ceiling of treatment room. This system can determine the positioning error in the form of three translations and three rotations according to the registration of two X-ray images acquired online and the planning CT image. An anthropomorphic head phantom and an anthropomorphic thorax phantom were used for this study. The phantom was set up on the treatment table with correct position and various “planned” setup errors. Both IGPS-O x-ray image-guided positioning system and the commercial On-board Imager Cone-beam Computed Tomography (OBI CBCT) were used to obtain the setup errors of the phantom. Difference of the Result between the two image-guided positioning systems were computed and analyzed. Results: The setup errors measured by IGPS-O x-ray image-guided positioning system and the OBI CBCT system showed a general agreement, the means and standard errors of the discrepancies between the two systems in the left-right, anterior-posterior, superior-inferior directions were −0.13±0.09mm, 0.03±0.25mm, 0.04±0.31mm, respectively. The maximum difference was only 0.51mm in all the directions and the angular discrepancy was 0.3±0.5° between the two systems. Conclusion: The spatial and angular discrepancies between IGPS-O system and OBI CBCT for setup error correction was minimal. There is a general agreement between the two positioning system. IGPS-O x-ray image-guided positioning system can achieve as good accuracy as CBCT and can be used in the clinical IGRT applications

  7. SU-E-P-54: Evaluation of the Accuracy and Precision of IGPS-O X-Ray Image-Guided Positioning System by Comparison with On-Board Imager Cone-Beam Computed Tomography

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, D; Wang, W; Jiang, B; Fu, D [Tianjin Medical University Cancer Institute and Hospital, Tianjin, Tianjin (China)

    2015-06-15

    Purpose: The purpose of this study is to assess the positioning accuracy and precision of IGPS-O system which is a novel radiographic kilo-voltage x-ray image-guided positioning system developed for clinical IGRT applications. Methods: IGPS-O x-ray image-guided positioning system consists of two oblique sets of radiographic kilo-voltage x-ray projecting and imaging devices which were equiped on the ground and ceiling of treatment room. This system can determine the positioning error in the form of three translations and three rotations according to the registration of two X-ray images acquired online and the planning CT image. An anthropomorphic head phantom and an anthropomorphic thorax phantom were used for this study. The phantom was set up on the treatment table with correct position and various “planned” setup errors. Both IGPS-O x-ray image-guided positioning system and the commercial On-board Imager Cone-beam Computed Tomography (OBI CBCT) were used to obtain the setup errors of the phantom. Difference of the Result between the two image-guided positioning systems were computed and analyzed. Results: The setup errors measured by IGPS-O x-ray image-guided positioning system and the OBI CBCT system showed a general agreement, the means and standard errors of the discrepancies between the two systems in the left-right, anterior-posterior, superior-inferior directions were −0.13±0.09mm, 0.03±0.25mm, 0.04±0.31mm, respectively. The maximum difference was only 0.51mm in all the directions and the angular discrepancy was 0.3±0.5° between the two systems. Conclusion: The spatial and angular discrepancies between IGPS-O system and OBI CBCT for setup error correction was minimal. There is a general agreement between the two positioning system. IGPS-O x-ray image-guided positioning system can achieve as good accuracy as CBCT and can be used in the clinical IGRT applications.

  8. Optimal beam focusing through turbulence.

    Science.gov (United States)

    Charnotskii, Mikhail

    2015-11-01

    Beam spread and beam wandering are the most perceptible effects of atmospheric turbulence on propagating laser beams. The width of the mean irradiance profile is typically used to characterize the beam spread. This so-called long-term (LT) statistic allows for a relatively simple theoretical description. However, the LT beam size is not a very practical measure of the beam spread because its measurements are sensitive to the movements of the source and detector, and to the large-scale variations of the refractive index that are not associated with turbulence. The short-term (ST) beam spread is measured relative to the instantaneous position of the beam center and is free of these drawbacks, but has not been studied as thoroughly as the LT spread. We present a theoretical model for the ST beam irradiance that is based on the parabolic equation for the beam wave propagation in random media, and the Markov approximation for calculation of the statistics of the optical field, and discuss an approximation that allows introduction of the isoplanatic ST point spread function (PSF). Unlike the LT PSF, the ST PSF depends on the overall beam geometry. This allows optimization of the initial beam field in terms of minimizing the ST beam size at the observation plane. Calculations supporting this conjecture are presented for the simple case of the coherent Gaussian beam, and Kolmogorov turbulence. PMID:26560908

  9. Optimal beam focusing through turbulence.

    Science.gov (United States)

    Charnotskii, Mikhail

    2015-11-01

    Beam spread and beam wandering are the most perceptible effects of atmospheric turbulence on propagating laser beams. The width of the mean irradiance profile is typically used to characterize the beam spread. This so-called long-term (LT) statistic allows for a relatively simple theoretical description. However, the LT beam size is not a very practical measure of the beam spread because its measurements are sensitive to the movements of the source and detector, and to the large-scale variations of the refractive index that are not associated with turbulence. The short-term (ST) beam spread is measured relative to the instantaneous position of the beam center and is free of these drawbacks, but has not been studied as thoroughly as the LT spread. We present a theoretical model for the ST beam irradiance that is based on the parabolic equation for the beam wave propagation in random media, and the Markov approximation for calculation of the statistics of the optical field, and discuss an approximation that allows introduction of the isoplanatic ST point spread function (PSF). Unlike the LT PSF, the ST PSF depends on the overall beam geometry. This allows optimization of the initial beam field in terms of minimizing the ST beam size at the observation plane. Calculations supporting this conjecture are presented for the simple case of the coherent Gaussian beam, and Kolmogorov turbulence.

  10. Diplexer for laser-beam heterodyne receiver

    Science.gov (United States)

    Koepf, G.

    1981-01-01

    Four prism interferometer superposes local oscillator beam on signal beam. Position of movable prism directs incident energy in both beams out one output port. Output port is spatially separated from input ports, and there is no limitation on size of frequency difference between laser beams.

  11. Relativistic electron beams above thunderclouds

    Directory of Open Access Journals (Sweden)

    M. Füllekrug

    2011-05-01

    Full Text Available Non-luminous relativistic electron beams above thunderclouds are detected by radio remote sensing with low frequency radio signals from 40–400 kHz. The electron beams occur 2–9 ms after positive cloud-to-ground lightning discharges at heights between 22–72 km above thunderclouds. The positive lightning discharges also cause sprites which occur either above or before the electron beam. One electron beam was detected without any luminous sprite occurrence which suggests that electron beams may also occur independently. Numerical simulations show that the beamed electrons partially discharge the lightning electric field above thunderclouds and thereby gain a mean energy of 7 MeV to transport a total charge of 10 mC upwards. The impulsive current associated with relativistic electron beams above thunderclouds is directed downwards and needs to be considered as a novel element of the global atmospheric electric circuit.

  12. Relativistic electron beams above thunderclouds

    DEFF Research Database (Denmark)

    Füellekrug, M.; Roussel-Dupre, R.; Symbalisty, E. M. D.;

    2011-01-01

    Non-luminous relativistic electron beams above thunderclouds have been detected by the radio signals of low frequency similar to 40-400 kHz which they radiate. The electron beams occur similar to 2-9 ms after positive cloud-to-ground lightning discharges at heights between similar to 22-72 km above...... thunderclouds. Intense positive lightning discharges can also cause sprites which occur either above or prior to the electron beam. One electron beam was detected without any luminous sprite which suggests that electron beams may also occur independently of sprites. Numerical simulations show that beams...... of electrons partially discharge the lightning electric field above thunderclouds and thereby gain a mean energy of similar to 7MeV to transport a total charge of similar to-10mC upwards. The impulsive current similar to 3 x 10(-3) Am-2 associated with relativistic electron beams above thunderclouds...

  13. Beam instrumentation performance overview

    CERN Document Server

    Sapinski, M

    2012-01-01

    The 2011 run has proven that LHC can operate safely and stably with higher bunch intensity and smaller transverse emittance than foreseen in the Technical Design Report. In this presentation the performance of the Beam Position Monitoring (BPM) system is discussed. The improvements to the system, those made during the last year and those expected to be done for 2012 run are presented. The status of the three types of devices measuring the transverse beam emittance, wire scanners (BWS), synchrotron radiation monitors (BSRT) and beam gas ionization monitors (BGI), are shown. The control room applications are reviewed and a set of improvements proposed by the operation team is presented.

  14. Isotropic beam bouquets for shaped beam linear accelerator radiosurgery

    Science.gov (United States)

    Wagner, Thomas H.; Meeks, Sanford L.; Bova, Frank J.; Friedman, William A.; Buatti, John M.; Bouchet, Lionel G.

    2001-10-01

    In stereotactic radiosurgery and radiotherapy treatment planning, the steepest dose gradient is obtained by using beam arrangements with maximal beam separation. We propose a treatment plan optimization method that optimizes beam directions from the starting point of a set of isotropically convergent beams, as suggested by Webb. The optimization process then individually steers each beam to the best position, based on beam's-eye-view (BEV) critical structure overlaps with the target projection and the target's projected cross sectional area at each beam position. This final optimized beam arrangement maintains a large angular separation between adjacent beams while conformally avoiding critical structures. As shown by a radiosurgery plan, this optimization method improves the critical structure sparing properties of an unoptimized isotropic beam bouquet, while maintaining the same degree of dose conformity and dose gradient. This method provides a simple means of designing static beam radiosurgery plans with conformality indices that are within established guidelines for radiosurgery planning, and with dose gradients that approach those achieved in conventional radiosurgery planning.

  15. 薄板激光焊机激光梁位置伺服系统%Position Servo System for Laser Beam of Laser Welding in Thin Strip Steel Plate

    Institute of Scientific and Technical Information of China (English)

    董砚; 杨洪; 王睿; 何林

    2012-01-01

    介绍了冷轧薄板生产线LW21L激光焊机激光梁位置伺服控制系统的相关工艺和控制方法.该位置伺服系统采用SIMODRIVE 611U变频、1FK7交流同步伺服电机和旋转编码器等电器.根据焊接工艺需要伺服系统的定位方式设置为手动控制和自动控制两种,定位系统设置为相对位置定位系统和绝对位置定位系统.采用PROFIBUS通信,保证了参数的快速、准确传递.该系统实现了切割光头和焊接光头的精确定位以及速度的闭环控制.%Technological process of servo system and control system for laser beam of LW21L type laser welder in cold rolled plate production line were introduced. Siemens SIMODR1VE 611U inverter, 1FK7 ac synchronous servo motor and revolving encoder were adopted in the control system. Manual localization way for the servo control system was set as manual control and automatic control, positioning system was set as relative positioning system and absolute positioning system according to the welding process. PROFIBUS was adopted to communicate,to ensure the parameters of the rapid and accurate transfer. This system realizes the cutting baldheaded and welding baldheaded of accurate location and speed closed-loop control.

  16. Fractal zone plate beam based optical tweezers

    Science.gov (United States)

    Cheng, Shubo; Zhang, Xinyu; Ma, Wenzhuo; Tao, Shaohua

    2016-01-01

    We demonstrate optical manipulation with an optical beam generated by a fractral zone plate (FZP). The experimental results show that the FZP beam can simultaneously trap multiple particles positioned in different focal planes of the FZP beam, owing to the multiple foci and self-reconstruction property of the FZP beam. The FZP beam can also be used to construct three-dimensional optical tweezers for potential applications. PMID:27678305

  17. Gaussian-Beam Laser-Resonator Program

    Science.gov (United States)

    Cross, Patricia L.; Bair, Clayton H.; Barnes, Norman

    1989-01-01

    Gaussian Beam Laser Resonator Program models laser resonators by use of Gaussian-beam-propagation techniques. Used to determine radii of beams as functions of position in laser resonators. Algorithm used in program has three major components. First, ray-transfer matrix for laser resonator must be calculated. Next, initial parameters of beam calculated. Finally, propagation of beam through optical elements computed. Written in Microsoft FORTRAN (Version 4.01).

  18. Beam - cavity interaction beam loading

    International Nuclear Information System (INIS)

    The interaction of a beam with a cavity and a generator in cyclic accelerators or storage rings is investigated. Application of Maxwell's equations together with the nonuniform boundary condition allows one to get an equivalent circuit for a beam-loaded cavity. The general equation for beam loading is obtained on the basis of the equivalent circuit, and the beam admittance is calculated. Formulas for power consumption by a beam-loaded cavity are derived, and the optimal tuning and coupling factor are analyzed. (author)

  19. 用PDCA循环减少电梯直梁孔位错的应用%The Application of PDCA Circulation Decreasing the Deviation of Hole Position in Straight Beam in Elevator

    Institute of Scientific and Technical Information of China (English)

    吕舒波; 周娟

    2012-01-01

    With the developing of market economy,competition between enterprises is becoming more and more fierce.Whether having a good product quality is a base of enterprises to adapt the market environment and to develop.Thus developing product quality is an essential method for enterprises to compete.This assay accords to A company as a reference.In order to improve the company's problem of the deviation of hole position in straight beam in elevator,we use PDCA circulation and CauseEffect/Fishbone Diagram to find out the cause of the problem and quality improvement's direction and method.%随着市场经济的不断增长,企业之间的竞争也日益激烈,能否拥有良好的产品质量是企业适应市场环境和发展的基础,所以提高产品质量的能力是企业竞争的必备手段。该文以A公司为研究对象,为了改进该公司的电梯直梁孔位的偏差问题,运用PDCA循环法及因果图,找出直梁孔位偏差的原因以及质量改进的方向和方法。

  20. Beam loading

    CERN Document Server

    Gamp, Alexander

    2013-01-01

    We begin by giving a description of the radio-frequency generator-cavity-beam coupled system in terms of basic quantities. Taking beam loading and cavity detuning into account, expressions for the cavity impedance as seen by the generator and as seen by the beam are derived. Subsequently methods of beam-loading compensation by cavity detuning, radio-frequency feedback and feedforward are described. Examples of digital radio-frequency phase and amplitude control for the special case of superconducting cavities are also given. Finally, a dedicated phase loop for damping synchrotron oscillations is discussed.

  1. Beam Instabilities

    CERN Document Server

    Rumolo, G

    2014-01-01

    When a beam propagates in an accelerator, it interacts with both the external fields and the self-generated electromagnetic fields. If the latter are strong enough, the interplay between them and a perturbation in the beam distribution function can lead to an enhancement of the initial perturbation, resulting in what we call a beam instability. This unstable motion can be controlled with a feedback system, if available, or it grows, causing beam degradation and loss. Beam instabilities in particle accelerators have been studied and analysed in detail since the late 1950s. The subject owes its relevance to the fact that the onset of instabilities usually determines the performance of an accelerator. Understanding and suppressing the underlying sources and mechanisms is therefore the key to overcoming intensity limitations, thereby pushing forward the performance reach of a machine.

  2. A computer algorithm for automatic beam steering

    Energy Technology Data Exchange (ETDEWEB)

    Drennan, E.

    1992-06-01

    Beam steering is done by modifying the current in a trim or bending magnet. If the current change is the right amount the beam can be made to bend in such a manner that it will hit a swic or BPM downstream from the magnet at a predetermined set point. Although both bending magnets and trim magnets can be used to modify beam angle, beam steering is usually done with trim magnets. This is so because, during beam steering the beam angle is usually modified only by a small amount which can be easily achieved with a trim magnet. Thus in this note, all steering magnets will be assumed to be trim magnets. There are two ways of monitoring beam position. One way is done using a BPM and the other is done using a swic. For simplicity, beam position monitoring in this paper will be referred to being done with a swic. Beam steering can be done manually by changing the current through a trim magnet and monitoring the position of the beam downstream from the magnet with a swic. Alternatively the beam can be positioned automatically using a computer which periodically updates the current through a specific number of trim magnets. The purpose of this note is to describe the steps involved in coming up with such a computer program. There are two main aspects to automatic beam steering. First a relationship between the beam position and the bending magnet is needed. Secondly a beamline setup of swics and trim magnets has to be chosen that will position the beam according to the desired specifications. A simple example will be looked at that will show that once a mathematical relationship between the needed change of the beam position on a swic and the change in trim currents is established, a computer could be programmed to calculate and update the trim currents.

  3. LHC Beam Instrumentation: Beam Profile Measurements (2/3)

    CERN Document Server

    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.

  4. Experimental Studies of Compensation of Beam-Beam Effects with Tevatron Electron Lenses

    Energy Technology Data Exchange (ETDEWEB)

    Shiltsev, V.; /Fermilab; Alexahin, Yu.; Bishofberger, Kip; Kamerdzhiev, V.; Parkhomchuk, V.; Reva, V.; Solyak, N.; Wildman, D.; Zhang, X.-L.; Zimmermann, F.; /Fermilab /Los Alamos /Novosibirsk, IYF /CERN

    2008-02-01

    Applying the space-charge forces of a low-energy electron beam can lead to a significant improvement of the beam-particle lifetime limit arising from the beam-beam interaction in a high-energy collider [1]. In this article we present the results of various beam experiments with 'electron lenses', novel instruments developed for the beam-beam compensation at the Tevatron, which collides 980-GeV proton and antiproton beams. We study the dependencies of the particle betatron tunes on the electron beam current, energy and position; we explore the effects of electron-beam imperfections and noises; and we quantify the improvements of the high-energy beam intensity and the collider luminosity lifetime obtained by the action of the Tevatron Electron Lenses.

  5. Dielectric barrier discharge source for supersonic beams

    Energy Technology Data Exchange (ETDEWEB)

    Luria, K.; Lavie, N.; Even, U. [Sackler School of Chemistry, Tel Aviv University, Tel Aviv 69978 (Israel)

    2009-10-15

    We present a new excitation source for pulsed supersonic beams. The excitation is based on dielectric barrier discharge in the beam. It produces cold beams of metastable atoms, dissociated neutral atoms from molecular precursors, and both positive and negative ions with high efficiency and reliability.

  6. The positioning accuracy study of the cone-beam computed tomography in combination with the sixdegree couch table%锥形束CT联合六自由度床的校位精度分析

    Institute of Scientific and Technical Information of China (English)

    胡彩容; 陆军; 张秀春; 吴君心; 潘建基

    2010-01-01

    目的 检测并分析我院引进的医科达图像引导放疗系统的锥形束CT(CBCT)的机械稳定性,及其联合六自由度床(HRTT)在放疗摆位时的校位精度.方法 测量X射线容积图像(XVI)系统的机械稳定性和重复性;研究可动部件(千伏级射线探测板和源方向球管支臂)的伸缩对XVI图像匹配结果的影响;同时比较骨配准和灰度值配准的精度;测量并分析HRTT在线性方向(x、y、z)和旋转方向(u、v、w)的校位精度.结果 XVI系统自身在线性和旋转方向上的重复性偏差分别≤0.4 mm和≤0.3°,说明该系统有较好的机械稳定性.HRTT联合XVI系统的总平均校位精度在线性方向和旋转方向分别≤0.6mm和≤0.4°.同时研究发现灰度值配准在精度上高于骨配准.结论 XVI系统的图像采集和配准过程具有较高的机械稳定性和较好的重复性;HRTT校正线性和旋转方向的摆位误差具有较高精度,其空间六自由度的校位功能结合CBCT技术的图像功能实现了图像引导放疗技术的临床应用.%Objective To scrutinize the positioning accuracy and reproducibility of the cone-beam computed tomography system in combination with the six-degree couch table (Hexapod Robot Treatment Table, HRTT). Methods The mechanical stability of the X-ray volume imaging (XVI) system was tested,in terms of the reproducibility. And the influence of the moveable parts, including the KV panel and the source arm, on the accuracy of the XVI image registration was analyzed. The accuracy between the bone and grey value registration was compared using a head-and-neck phantom. The accuracy of the HRTT for translational, rotational, and a combination of translational and rotational corrections was investigated in consecutive measurements. Results The performance of XVI system itself was stable with translational and rotational error of below 0. 4 mm and below 0. 3°, respectively. The mean position accuracy of the XVI system in

  7. LHC beam instrumentation detectors and acquisition systems

    International Nuclear Information System (INIS)

    An overview of some of the detectors and acquisition systems being developed for measuring and controlling beam parameters in the LHC. The two largest systems concern the measurement of beam position, with over 1000 monitors, and beam loss, with over 3000 monitors. For the beam position system a novel wide band time normaliser has been developed to allow bunch-by-bunch 40MHz acquisitions with a dynamic range greater than 30dB and an overall linearity of better than 1%. Also mentioned will be the acquisition system for the fast beam current transformers and the development of CdTe detectors for luminosity monitoring. [author

  8. Beam energy online measurement of BEPCII LINAC

    CERN Document Server

    Wang, Shao-Zhe; Chi, Yun-Long

    2015-01-01

    This paper describes beam energy online measurement of BEPCII linac, presents the calculation formula and some of the results. The method mentioned here measures the beam energy by acquiring beam positions in the horizontal direction with three beam position monitors (BPM) eliminating the effect of orbit fluctuation, which is much better than the one using the single BPM. The error analysis indicates that this online measurement has further potential usage such as a part of beam energy feedback system. The reliability of this method is also discussed and demonstrated in the end of this paper.

  9. Controlling Second Harmonic Efficiency of Laser Beam Interactions

    Science.gov (United States)

    Barnes, Norman P. (Inventor); Walsh, Brian M. (Inventor); Reichle, Donald J. (Inventor)

    2011-01-01

    A method is provided for controlling second harmonic efficiency of laser beam interactions. A laser system generates two laser beams (e.g., a laser beam with two polarizations) for incidence on a nonlinear crystal having a preferred direction of propagation. Prior to incidence on the crystal, the beams are optically processed based on the crystal's beam separation characteristics to thereby control a position in the crystal along the preferred direction of propagation at which the beams interact.

  10. Beam Time Accounting

    CERN Document Server

    Seitova, Diana

    2016-01-01

    ISOLDE is one of the leading research facilities in the field of nuclear physics. A proton beam with an energy 1.4 GeV coming from the Proton Synchrotron Booster (PSB) hits one of the targets at ISOLDE and produces Radioactive Ion Beams (RIBs). Then, the RIBs of interest is selected and delivered to the different experimental stations. In order to deliver the beam to the certain experimental station, the positions of the devices along the beamline should satisfy certain conditions. The purpose of this project is to define the conditions for the beam to pass through the different beamlines and to store the data about device’s status for later analysis and statistics, so it would be possible to know when the beam was used for different experiments. The data with the settings of the different devices is saved in the Timber database and the first steps for making virtual devices to compile the status of the beamlines were completed.

  11. Improvements on the accuracy of beam bugs

    International Nuclear Information System (INIS)

    At LLNL resistive wall monitors are used to measure the current and position used on ETA-II show a droop in signal due to a fast redistribution time constant of the signals. This paper presents the analysis and experimental test of the beam bugs used for beam current and position measurements in and after the fast kicker. It concludes with an outline of present and future changes that can be made to improve the accuracy of these beam bugs. of intense electron beams in electron induction linacs and beam transport lines. These, known locally as ''beam bugs'', have been used throughout linear induction accelerators as essential diagnostics of beam current and location. Recently, the development of a fast beam kicker has required improvement in the accuracy of measuring the position of beams. By picking off signals at more than the usual four positions around the monitor, beam position measurement error can be greatly reduced. A second significant source of error is the mechanical variation of the resistor around the bug

  12. Improvements on the accuracy of beam bugs

    International Nuclear Information System (INIS)

    At LLNL resistive wall monitors are used to measure the current and position used on ETA-II show a droop in signal due to a fast redistribution time constant of the signals. This paper presents the analysis and experimental test of the beam bugs used for beam current and position measurements in and after the fast kicker. It concludes with an outline of present and future changes that can be made to improve the accuracy of these beam bugs. of intense electron beams in electron induction linacs and beam transport lines. These, known locally as beam bugs, have been used throughout linear induction accelerators as essential diagnostics of beam current and location. Recently, the development of a fast beam kicker has required improvement in the accuracy of measuring the position of beams. By picking off signals at more than the usual four positions around the monitor, beam position measurement error can be greatly reduced. A second significant source of error is the mechanical variation of the resistor around the bug

  13. 俯卧位外照射治疗早期阴茎癌%External beam treatment of men with early stage carcinoma of the penis in prone position

    Institute of Scientific and Technical Information of China (English)

    杨波; 秦丽娟; 赵于天; 杨伟强; 张福正

    2011-01-01

    Objective To introduce a novel immobilization device for external beam treatment of men with early stage carcinoma of the penis in prone position and assess its clinical value for post - operation radiation therapy of early stage carcinoma of the penis. Methods Twenty - six patients diagnosed with early stage carcinoma of the penis were recruited in this study. All the patients were stage I according to Jackson's staging system and 23 cases were T1N0M 0 and 3 cases were T1N1M0 according to American Joint Committee on Cancer ( AJCC) staging system. Before radiotherapy , 15 patients received wedge shaped resection of the primary tumor and local excision was performed on the rest 11 patients. During 5-6.5 weeks of radiotherapy, the penis and/or the bilateral inguinal lymph node region were prescribed 55 ~ 66 Gy. To reproduce the target position between fractions, a special container filling with water was designed to immobilize the penis and the patients were treated in prone position. Results During a median follow - up of X years (8 months to 7 years), two patients failed to follow up after 3 and 4 years of survival. One patient died of distant metastasis after 4. 5 years of survival, one patient died of distant metastasis after 5. 5 years of survival, one patient died of cerebrovascular accident after 6 years of survival, and the remains were followed up until present. Local control rate and 5 - year survival rate were up to 100% and 85.71%. Radiation induced dermatitis and penis swelling were observed and relieved after symptomatic treatment for all patients. No severe reactions such as dysuria, urethral fistula, skin ulceration, lower extremity edema and urethral stenosis were observed. Conclusion For early stage carcinoma of the penis, the proposed water immobilization device ensures great reproduction of the penis position between fractions , providing a treatment option other than conventional treatment in supine position . The follow up shows improvement of

  14. Beta Beams Implementation at CERN

    CERN Document Server

    Hansen, Christian

    2011-01-01

    Beta Beam,the concept of generating a pure and intense (anti) neutrino beam by letting accelerated radioactive ions beta decay in a storage ring, called Decay Ring (DR), is the base of one of the proposed next generation neutrino oscillation facilities, necessary for a complete study of the neutrino oscillation parameter space. Sensitivities of the unknown neutrino oscillation parameters depend on the Decay Ring's ion intensity and of it's duty factor (the filled ratio of the ring). Therefore efficient ion production, stripping, bunching, acceleration and storing are crucial sub-projects under study and development within the Beta Beam collaboration. Specifically the feasibility of these tasks as parts of a Beta Beam implementation at CERN will be discussed in this report. The positive impact of the large {\\theta}13 indications from T2K on the Beta Beam performance will also be discussed.

  15. R&D of the Fluoroscopes of 100 MeV Cyclotron Beam Lines

    Institute of Scientific and Technical Information of China (English)

    YIN; Meng; GUAN; Feng-ping; XIE; Huai-dong; ZHENG; Xia; XING; Jian-sheng; LV; Yin-long

    2013-01-01

    Beijing Radioactive Ion-beam Facility(BRIF)consists of a 100 MeV H-cyclotron CYCIAE-100and nine beam lines.All the beam lines provide the channels of the proton beam or the neutron beam to the terminal of physics experiment.There are many beam diagnosis monitors distributing along the beam lines,including,Faraday cups,beam position monitors,fluoroscopes,collimators,emittance measurement

  16. Beam Diagnostics for the J-PARC Main Ring Synchrotron

    CERN Document Server

    Toyama, Takeshi; Hashimoto, Yoshinori; Hayashi, Naoki; Kishiro, Junichi; Lee, Seishu; Miura, Takako; Muto, Suguru; Toyokawa, Ryoji

    2005-01-01

    Beam diagnostics: beam intensity monitors (DCCT, SCT, FCT, WCM), beam position monitors (ESM), beam loss monitors (proportional chamber, air ion chamber), beam profile monitors (secondary electron emission, gas-sheet) have been designed, tested, and will be installed for the Main Ring synchrotron of J-PARC (Japan Proton Accelerator Research Complex). This paper describes the basic design principle and specification of each monitor, with a stress on how to cope with high power beam (average circulation current of ~12 A) and low beam loss operation (less than 1 W/m except a collimator region). Some results of preliminary performance test using present beams and a radiation source will be reported.

  17. Uncertainty of cesium-beam time standards due to beam asymmetry

    Science.gov (United States)

    Becker, G.

    1980-12-01

    As a consequence of the spatial phase distribution in the resonators of cesium-beam time and frequency standards, the generated frequency depends on the specific path of the atomic beam. A change of the position of the atomic beam source may result in a beam displacement normal to the beam direction. For a deflection system consisting of a combination of quadrupole and hexapole magnets for two-dimensional beam deflection, the displacement of the center of mass of the beam resulting from a misalignment of the beam source is computed. To this end, the distribution of the beam intensity on the collector is first determined. It is shown that for the cesium-beam time and frequency standard CS1 of the Physikalisch-Technische Bundesanstalt (PTB), the uncertainty of the position of the center of mass of the beam entails a contribution to the uncertainty of the standard of less than 1 x 10 to the -15th. The amount of the displacement of the center of mass of the beam can be determined from the decrease of the beam flux on the collector caused by an adjustment of the beam source.

  18. Relativistic electron beams above thunderclouds

    Directory of Open Access Journals (Sweden)

    M. Füllekrug

    2011-08-01

    Full Text Available Non-luminous relativistic electron beams above thunderclouds have been detected by the radio signals of low frequency ∼40–400 kHz which they radiate. The electron beams occur ∼2–9 ms after positive cloud-to-ground lightning discharges at heights between ∼22–72 km above thunderclouds. Intense positive lightning discharges can also cause sprites which occur either above or prior to the electron beam. One electron beam was detected without any luminous sprite which suggests that electron beams may also occur independently of sprites. Numerical simulations show that beams of electrons partially discharge the lightning electric field above thunderclouds and thereby gain a mean energy of ∼7 MeV to transport a total charge of ∼−10 mC upwards. The impulsive current ∼3 × 10−3 Am−2 associated with relativistic electron beams above thunderclouds is directed downwards and needs to be considered as a novel element of the global atmospheric electric circuit.

  19. Impact of Dynamic Magnetic fields on the CLIC Main Beam

    CERN Document Server

    Snuverink, J; Jach, C; Jeanneret, JB; Schulte, D; Stulle, F

    2010-01-01

    The Compact Linear Collider (CLIC) accelerator has strong precision requirements on the position of the beam. The beam position will be sensitive to external dynamic magnetic fields (stray fields) in the nanotesla regime. The impact of these fields on the CLIC main beam has been studied by performing simulations on the lattices and tolerances have been determined. Several mitigation techniques will be discussed.

  20. Nursing Positions

    Science.gov (United States)

    ... Story" 5 Things to Know About Zika & Pregnancy Nursing Positions KidsHealth > For Parents > Nursing Positions Print A ... and actually needs to feed. Getting Comfortable With Breastfeeding Nursing can be one of the most challenging ...

  1. Use of beam deflection to control an electron beam wire deposition process

    Science.gov (United States)

    Taminger, Karen M. (Inventor); Hofmeister, William H. (Inventor); Hafley, Robert A. (Inventor)

    2013-01-01

    A method for controlling an electron beam process wherein a wire is melted and deposited on a substrate as a molten pool comprises generating the electron beam with a complex raster pattern, and directing the beam onto an outer surface of the wire to thereby control a location of the wire with respect to the molten pool. Directing the beam selectively heats the outer surface of the wire and maintains the position of the wire with respect to the molten pool. An apparatus for controlling an electron beam process includes a beam gun adapted for generating the electron beam, and a controller adapted for providing the electron beam with a complex raster pattern and for directing the electron beam onto an outer surface of the wire to control a location of the wire with respect to the molten pool.

  2. Positioning consumption

    DEFF Research Database (Denmark)

    Halkier, Bente; Keller, Margit

    2014-01-01

    This article analyses the ways in which media discourses become a part of contested consumption activities. We apply a positioning perspective with practice theory to focus on how practitioners relate to media discourse as a symbolic resource in their everyday practices. A typology of performance...... positionings emerges based on empirical examples of research in parent–children consumption. Positionings are flexible discursive fixations of the relationship between the performances of the practitioner, other practitioners, media discourse and consumption activities. The basic positioning types...

  3. Positive Psychology

    Science.gov (United States)

    Peterson, Christopher

    2009-01-01

    Positive psychology is a deliberate correction to the focus of psychology on problems. Positive psychology does not deny the difficulties that people may experience but does suggest that sole attention to disorder leads to an incomplete view of the human condition. Positive psychologists concern themselves with four major topics: (1) positive…

  4. External Beam Therapy (EBT)

    Science.gov (United States)

    ... Physician Resources Professions Site Index A-Z External Beam Therapy (EBT) External beam therapy (EBT) is a ... follow-up should I expect? What is external beam therapy and how is it used? External beam ...

  5. Ubiquitous positioning

    CERN Document Server

    Mannings, Robin

    2008-01-01

    This groundbreaking resource offers a practical, in-depth understanding of Ubiquitous Positioning - positioning systems that identify the location and position of people, vehicles and objects in time and space in the digitized networked economy. The future and growth of ubiquitous positioning will be fueled by the convergence of many other areas of technology, from mobile telematics, Internet technology, and location systems, to sensing systems, geographic information systems, and the semantic web. This first-of-its-kind volume explores ubiquitous positioning from a convergence perspective, of

  6. Status of Beam Diagnostic Systems for the PEFP

    CERN Document Server

    Park Jang Ho; Choi Byung Ho; Ha Hwang Woon; Han, Sang-Hyo; Park, Sung-Ju; Woon Parc, Yong; Yun Huang Jung

    2005-01-01

    A proton linear accelerator is currently the construction at the KAERI (Korea Atomic Research Institute) to the PEFP (Proton Engineering Frontier Project) in Korea. We are accomplished the technique development of beam diagnostic system to be currently the construction. We treat beam diagnostics for the high power proton linear accelerator. Prototype beam position & phase monitor (BPPM) electronics was made and tested successfully in one of the beam diagnostic systems. The beam position monitor pickup electrode is a capacitive type (electrostatic type) which has a button form. Button form electrode, in common use around electron synchrotrons and storage rings, are a variant of the electrode with small button form (e.g., sub mm diameter). However, we are designed button form electrode to measure beam position of proton beam. The BCM (Beam Current Monitor) is developed Tuned CT (Current Transformer) for collaborate with Bergoz Instruments. This paper describes the status of beam diagnostic systems for the P...

  7. Monitoring the extracted proton beam at the SPS

    CERN Multimedia

    1977-01-01

    Fluorescent screens in front of the target positions allow a precise adjustement in front of them. A similar photo was recorded at the beam dump at the beam injection into the SPS, see Weekly Bulletin of April 1976.

  8. Laser beam steering device

    Science.gov (United States)

    Motamedi, M. E.; Andrews, A. P.; Gunning, W. J.

    1993-01-01

    Agile beam steering is a critical requirement for airborne and space based LIDAR and optical communication systems. Design and test results are presented for a compact beam steering device with low inertia which functions by dithering two complementary (positive and negative) binary optic microlens arrays relative to each other in directions orthogonal to the direction of light propagation. The miniaturized system has been demonstrated at scan frequencies as high as 300 Hz, generating a 13 x 13 spot array with a total field of view of 2.4 degrees. The design is readily extendable to a 9.5 degree field of view and a 52 x 52 scan pattern. The system is compact - less than 2 in. on a side. Further size reductions are anticipated.

  9. Slow light beam splitter.

    Science.gov (United States)

    Xiao, Yanhong; Klein, Mason; Hohensee, Michael; Jiang, Liang; Phillips, David F; Lukin, Mikhail D; Walsworth, Ronald L

    2008-07-25

    We demonstrate a slow light beam splitter using rapid coherence transport in a wall-coated atomic vapor cell. We show that particles undergoing random and undirected classical motion can mediate coherent interactions between two or more optical modes. Coherence, written into atoms via electromagnetically induced transparency using an input optical signal at one transverse position, spreads out via ballistic atomic motion, is preserved by an antirelaxation wall coating, and is then retrieved in outgoing slow light signals in both the input channel and a spatially-separated second channel. The splitting ratio between the two output channels can be tuned by adjusting the laser power. The slow light beam splitter may improve quantum repeater performance and be useful as an all-optical dynamically reconfigurable router.

  10. Satellite positioning

    Science.gov (United States)

    Colombo, Oscar L.; Watkins, Michael M.

    1991-01-01

    Developments in satellite positioning techniques and their applications are reviewed on the basis of the theoretical and practical work published by U.S. researchers in 1987-1990. Current techniques are classified into two main categories: satellite laser tracking and radio tracking. Particular attention is given to the Geoscience Laser Ranging System, the Lunar Laser Ranging concept; GPS ephemerides determination, fiducial networks, and reference frame; static GPS positioning; and kinematic GPS positioning.

  11. Beam quality measure for vector beams.

    Science.gov (United States)

    Ndagano, Bienvenu; Sroor, Hend; McLaren, Melanie; Rosales-Guzmán, Carmelo; Forbes, Andrew

    2016-08-01

    Vector beams have found a myriad of applications, from laser materials processing to microscopy, and are now easily produced in the laboratory. They are usually differentiated from scalar beams by qualitative measures, for example, visual inspection of beam profiles after a rotating polarizer. Here we introduce a quantitative beam quality measure for vector beams and demonstrate it on cylindrical vector vortex beams. We show how a single measure can be defined for the vector quality, from 0 (purely scalar) to 1 (purely vector). Our measure is derived from a quantum toolkit, which we show applies to classical vector beams. PMID:27472580

  12. Application of optical fiber beam loss monitor

    International Nuclear Information System (INIS)

    KEK is an accelerator complex consisting of an electron-positron injector linac and various types of circular accelerators. In order to protect instruments from radiation damage, discrete beam loss monitors have been installed inside the linac and rings. Although beam losses can be detected using the beam loss monitors (BLMs) or beam position monitors (BPMs), it is difficult to identify the exact position of the loss. The electrons, which strike the duct, lose a fraction of their beam energy, which produces a shower at the location and emits many electrons out of the duct. If an optical fiber is placed inside the beam duct, many of these electrons will pass through the optical fiber where the beam loss is generated. BLMs employing an optical fiber based on Cherenkov radiation are currently being developed and applied to our system. An optical fiber placed into the duct also can be used as a detector for a wire scanner system. Existing wire scanner detectors are set at a fixed position, and detect signals of different beam energies that correspond to the different injection modes. However, the fixed position is not always optimal. Conversely, owing to the optical fiber's distributing nature, optical fiber detector systems containing PMTs enables the effective detection of all signals from various beam modes. We can successfully obtain the clear wire scanner signal by employing this optical fiber system. The measurement of the beam loss at the incidence part of the circular accelerator is also described. The beam loss location as well as the turn-by-turn beam loss can be measured. (author)

  13. Laser beam riding artillery missiles guidance device is designed

    Science.gov (United States)

    Yan, Mingliang; Huo, Zhicheng; Chen, Wei

    2014-09-01

    Laser driving gun missile guidance type beam of laser information field formed by any link failure or reduced stability will directly lead to ballistic or miss out of control, and based on this, this paper designed the driving beam of laser guided missile guidance beam type forming device modulation and zoom mechanism, in order to make the missile can recognize its position in the laser beam, laser beam gun missile, by means of spatial encoding of the laser beam laser beam into information after forming device, a surface to achieve the purpose of precision guidance.

  14. Positive Psychotherapy

    Science.gov (United States)

    Seligman, Martin E. P.; Rashid, Tayyab; Parks, Acacia C.

    2006-01-01

    Positive psychotherapy (PPT) contrasts with standard interventions for depression by increasing positive emotion, engagement, and meaning rather than directly targeting depressive symptoms. The authors have tested the effects of these interventions in a variety of settings. In informal student and clinical settings, people not uncommonly reported…

  15. Positioning Agility

    Science.gov (United States)

    Oza, Nilay; Abrahamsson, Pekka; Conboy, Kieran

    Agile methods are increasingly adopted by European companies. Academics too are conducting numerous studies on different tenets of agile methods. Companies often feel proud in marketing themselves as ‘agile’. However, the true notion of ‘being agile’ seems to have been overlooked due to lack of positioning of oneself for agility. This raises a call for more research and interactions between academia and the industry. The proposed workshop refers to this call. It will be highly relevant to participants, interested in positioning their company’s agility from organizational, group or project perspectives. The positioning of agility will help companies to better align their agile practices with stakeholder values. Results of the workshop will be shared across participants and they will also have opportunity to continue their work on agile positioning in their companies. At broader level, the work done in this workshop will contribute towards developing Agile Positioning System.

  16. Stable beams

    CERN Multimedia

    2015-01-01

    Stable beams: two simple words that carry so much meaning at CERN. When LHC page one switched from "squeeze" to "stable beams" at 10.40 a.m. on Wednesday, 3 June, it triggered scenes of jubilation in control rooms around the CERN sites, as the LHC experiments started to record physics data for the first time in 27 months. This is what CERN is here for, and it’s great to be back in business after such a long period of preparation for the next stage in the LHC adventure.   I’ve said it before, but I’ll say it again. This was a great achievement, and testimony to the hard and dedicated work of so many people in the global CERN community. I could start to list the teams that have contributed, but that would be a mistake. Instead, I’d simply like to say that an achievement as impressive as running the LHC – a machine of superlatives in every respect – takes the combined effort and enthusiasm of everyone ...

  17. Beam propagation

    International Nuclear Information System (INIS)

    The main part of this thesis consists of 15 published papers, in which the numerical Beam Propagating Method (BPM) is investigated, verified and used in a number of applications. In the introduction a derivation of the nonlinear Schroedinger equation is presented to connect the beginning of the soliton papers with Maxwell's equations including a nonlinear polarization. This thesis focuses on the wide use of the BPM for numerical simulations of propagating light and particle beams through different types of structures such as waveguides, fibers, tapers, Y-junctions, laser arrays and crystalline solids. We verify the BPM in the above listed problems against other numerical methods for example the Finite-element Method, perturbation methods and Runge-Kutta integration. Further, the BPM is shown to be a simple and effective way to numerically set up the Green's function in matrix form for periodic structures. The Green's function matrix can then be diagonalized with matrix methods yielding the eigensolutions of the structure. The BPM inherent transverse periodicity can be untied, if desired, by for example including an absorptive refractive index at the computational window edges. The interaction of two first-order soliton pulses is strongly dependent on the phase relationship between the individual solitons. When optical phase shift keying is used in coherent one-carrier wavelength communication, the fiber attenuation will suppress or delay the nonlinear instability. (orig.)

  18. Beam structure and transverse emittance studies of high-energy ion beams

    International Nuclear Information System (INIS)

    A visual diagnostic technique has been developed to monitor and study ion-beam structure, shape, and size along a transport line. In this technique, a commercially available fluorescent screen is used in conjunction with a video camera. The visual representation of the beam structure is digitized enhanced through false-color coding, and displayed on a TV monitor for on-line viewing. The digitized information is stored for further off-line processing (e.g.,extraction of beam profiles). An optional wire grid placed upstream of the fluor screen adds the capability of measuring transverse emittance (or angular spread). This technique allows real-time observation of the beam response to parameter changes (e.g., evolution of the beam structure, shifts in the beam intensity at various spatial locations within the beam perimeter, and shifts in the beam center and position)

  19. 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.

  20. Dynamic acoustic tractor beams

    Energy Technology Data Exchange (ETDEWEB)

    Mitri, F. G., E-mail: F.G.Mitri@ieee.org [Chevron, Area 52 Technology – ETC, Santa Fe, New Mexico 87508 (United States)

    2015-03-07

    Pulling a sphere and vibrating it around an equilibrium position by amplitude-modulation in the near-field of a single finite circular piston transducer is theoretically demonstrated. Conditions are found where a fluid hexane sphere (with arbitrary radius) chosen as an example, centered on the axis of progressive propagating waves and submerged in non-viscous water, experiences an attractive (steady) force pulling it towards the transducer, as well as an oscillatory force forcing it to vibrate back-and-forth. Numerical predictions for the dynamic force illustrate the theory and suggest an innovative method in designing dynamic acoustical tractor beams.

  1. Dynamic acoustic tractor beams

    Science.gov (United States)

    Mitri, F. G.

    2015-03-01

    Pulling a sphere and vibrating it around an equilibrium position by amplitude-modulation in the near-field of a single finite circular piston transducer is theoretically demonstrated. Conditions are found where a fluid hexane sphere (with arbitrary radius) chosen as an example, centered on the axis of progressive propagating waves and submerged in non-viscous water, experiences an attractive (steady) force pulling it towards the transducer, as well as an oscillatory force forcing it to vibrate back-and-forth. Numerical predictions for the dynamic force illustrate the theory and suggest an innovative method in designing dynamic acoustical tractor beams.

  2. Continuous Reinforced Concrete Beams

    DEFF Research Database (Denmark)

    Hoang, Cao Linh; Nielsen, Mogens Peter

    1996-01-01

    This report deals with stress and stiffness estimates of continuous reinforced concrete beams with different stiffnesses for negative and positive moments e.g. corresponding to different reinforcement areas in top and bottom. Such conditions are often met in practice.The moment distribution...... at the limit state of serviceability is in some simple cases determined by setting up the statical and the compatibility conditions.With these moment distributions, the maximum deflection and the reinforcement stresses at the span middle and at a support are calculated.The results are compared with results...

  3. Researcher positioning

    DEFF Research Database (Denmark)

    Mørck, Line Lerche; Khawaja, Iram

    2009-01-01

    abstract  This article focuses on the complex and multi-layered process of researcher positioning, specifically in relation to the politically sensitive study of marginalised and ‘othered' groups such as Muslims living in Denmark. We discuss the impact of different ethnic, religious and racial...... political and personal involvement by the researcher, which challenges traditional perspectives on research and researcher positioning. A key point in this regard is the importance of constant awareness of and reflection on the multiple ways in which one's positioning as a researcher influences the research...... process. Studying the other calls for close reflections on one's own position, theoretically, personally, and politically, taking into account one's complicity in either overcoming or reproducing processes of othering and marginalisation. [i] We use the term (ethnic) minoritised, not as a distinction...

  4. Beam diagnostics instrumentation for the high energy beam transfer line of I.P.H.I

    Energy Technology Data Exchange (ETDEWEB)

    Ausset, P.; Berthelot, S.; Coacolo, J.L.; Lesrel, J.; Maymon, J.N.; Olivier, A.; Rouviere, N.; Solal, M.; Vatrinet, L.; Yaniche, J.F. [Institut de Physique Nucleaire, (IN2P3/CNRS) 91 - Orsay (France); Belyaev, G.; Roudskoy, I. [I.T.E.P. Moscow (Russian Federation)

    2005-07-01

    I.P.H.I. is a High Intensity Proton Injector under construction at Saclay. An E.C.R. source produces a 100 keV, 100 mA C.W. proton beam which will be accelerated at 3 MeV by a 4 vanes R.F.Q. operating at 352.2 MHz. Finally, a High Energy Beam Transport Line (H.E.B.T.) will deliver the beam to a beam stopper and will be equipped with appropriate beam diagnostics to carry intensity, centroid beam transverse position, transverse beam profiles, beam energy and energy spread measurements for the commissioning of I.P.H.I. These beam diagnostics will operate under both pulsed and C.W. operation. Transverse beam profile measurements will be acquired under low and high duty factor pulsed beam operation using a slow wire scanner and a C.C.D. camera to image the beam-induced fluorescence. The beam instrumentation of the H.E.B.T. is reviewed and preliminary obtained transverse profile measurements at 100 keV are described. (authors)

  5. Beam Diagnostics Instrumentation for the High Energy Beam Transport Line of I.P.H.I.

    CERN Document Server

    Ausset, P; Coacolo, J L; Lesrel, J; Maymon, J N; Olivier, A; Rouviere, N; Solal-Cohen, M; Vatrinet, L; Yaniche, J F

    2005-01-01

    I.P.H.I. is a High Intensity Proton Injector under construction at Saclay (C.N.R.S/ I.N.2P.3; C.E.A. / D.A.P.N.I.A and C.E.R.N. collaboration). An E.C.R. produces a 100 keV, 100 mA C.W. proton beam which will be accelerated at 3 MeV by a 4 vanes R.F.Q. operating at 352.2 MHz. Finally, a High Energy Beam Transport Line (H.E.B.T.) will deliver the beam to a beam stopper and will be equipped with appropriate beam diagnostics to carry intensity; centroïd beam transverse position, transverse beam profiles, beam energy and energy spread measurements for the commissioning of I.P.H.I. These beam diagnostics will operate under both pulsed and C.W. operation. Transverse beam profile measurements will be acquired under low and high duty factor pulsed beam operation using a slow wire scanner and a C.C.D. camera to image the beam-induced fluorescence. The beam instrumentation of the H.E.B.T. is reviewed and preliminary obtained transverse profile measurements at 100 keV are described.

  6. Gathering positive experience

    CERN Multimedia

    2009-01-01

    Last Monday, the new CERN Machine Advisory Committee (CMAC) met for the first time, and we had good news to tell its members. Over the weekend, injection tests for both LHC beams were successfully carried out. In other words, we’ve had beam in the LHC for the first time since September 2008. That’s a good feeling, but it’s no reason for complacency. There’s still a long way to go before first physics at the new energy frontier. As the Bulletin has reported over recent weeks, we’re gathering a lot of positive experience with the new quench detection and protection system (QPS), which is already allowing us to monitor the LHC far better than we were able to in the past. So far, the QPS for three of the LHC’s eight sectors has been put through its paces, and we’ve also power tested those sectors to 2000 amperes, the equivalent of around 1.2 TeV per beam. The next step is to slowly increase the current to 4000 amperes, and...

  7. Low energy beam transport system developments

    Science.gov (United States)

    Dudnikov, V.; Han, B.; Stockli, M.; Welton, R.; Dudnikova, G.

    2015-04-01

    For high brightness beam production it is important to preserve the brightness in the low energy beam transport system (LEBT) used to transport and match the ion beams to the next stage of acceleration, usually an RFQ. While electrostatic focusing can be problematic for high current beam transport, reliable electrostatic LEBT operation has been demonstrated with H- beams up to 60 mA. Now, however, it is commonly accepted that an optimal LEBT for high current accelerator applications consists of focusing solenoids with space charge compensation. Two-solenoid LEBTs are successfully used for high current (>100 mA) proton beam transport. Preservation of low emittances (~0.15 π mm-mrad) requires the addition of a heavy gas (Xe, Kr), which causes ~5% of proton loss in a 1 m long LEBT. Similar Xe densities would be required to preserve low emittances of H- beams, but such gas densities cause unacceptably high H- beam losses. A short LEBT with only one short solenoid, movable for RFQ matching, can be used for reduced negative ion stripping. A strong electrostatic-focusing LEBT has been successfully adopted for transport of high current H- beams in the SNS Front End. Some modifications of such electrostatic LEBTs are expected to improve the reliable transport of intense positive and negative ion beams without greatly degrading their low emittances. We concentrate on processes that determine the beam brightness degradation and on their prevention. Proposed improvements to the SNS electrostatic LEBT are discussed.

  8. Beam-beam effects in the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Shiltsev, V.; Alexahin, Y.; Lebedev, V.; Lebrun, P.; Moore, R.S.; Sen, T.; Tollestrup, A.; Valishev, A.; Zhang, X.L.; /Fermilab

    2005-01-01

    The Tevatron in Collider Run II (2001-present) is operating with 6 times more bunches, many times higher beam intensities and luminosities than in Run I (1992-1995). Electromagnetic long-range and head-on interactions of high intensity proton and antiproton beams have been significant sources of beam loss and lifetime limitations. We present observations of the beam-beam phenomena in the Tevatron and results of relevant beam studies. We analyze the data and various methods employed in operations, predict the performance for planned luminosity upgrades, and discuss ways to improve it.

  9. Formation of thin film of negative and positive ions

    Energy Technology Data Exchange (ETDEWEB)

    Horino, Yuji; Tsubouchi, Nobuteru [Osaka National Research Inst., AIST, Ikeda (Japan)

    1997-02-01

    Positive and negative ions deposition apparatus (PANDA) was developed by us as new synthesis method of materials. This apparatus is able to form simultaneously or independently the positive and negative ion beams to separate the mass and to control the energy from 10 eV to 3 KeV. It consists of positive beam line, negative beam line and a film formation room. Microwave discharge ion source and plasma sputtering source are used as the positive ion and the negative ion source, respectably. The beam generation test was carried out. The negative ion beams were generated from silicon wafer (target) and measured by MS. The mass spectrum of extracted negative silicon beams showed mass number 28, 29, and 30 of Si{sup -} and Si{sub 2}{sup -}. It proved that ions were separated in the isotope level. Therefore, film, it`s purity is isotope level, may be formed by such ion beams. (S.Y.)

  10. Explicit free‐floating beam element

    DEFF Research Database (Denmark)

    Nielsen, Martin Bjerre; Krenk, Steen

    2014-01-01

    A two‐node free‐floating beam element capable of undergoing arbitrary large displacements and finite rotations is presented in explicit form. The configuration of the beam in three‐dimensional space is represented by the global components of the position of the beam nodes and an associated set of...... interpolation of kinematic variables, resulting in a locking‐free formulation in terms of three explicit matrices. A set of classic benchmark examples illustrates excellent performance of the explicit beam element. Copyright © 2014 John Wiley & Sons, Ltd....

  11. AA, beam stopper with scintillator screen

    CERN Multimedia

    1980-01-01

    An insertable steel-plate beam stopper was located after nearly a full turn downstream of the injection point. It was fitted with a scintillator screen, a thin plate of Cr-doped alumina, imprinted with a grid and reference points. The screen was illuminated through a window and observed with a highly sensitive TV camera plus image intensifier. This allowed observation of beam position and size of a proton test beam and of the beam from the target, which consisted not only of antiprotons but contained as well electrons, pions and muons of the same momentum.

  12. Positional games

    CERN Document Server

    Hefetz, Dan; Stojaković, Miloš; Szabó, Tibor

    2014-01-01

    This text serves as a thorough introduction to the rapidly developing field of positional games. This area constitutes an important branch of combinatorics, whose aim it is to systematically develop an extensive mathematical basis for a variety of two-player perfect information games. These range from such popular games as Tic-Tac-Toe and Hex to purely abstract games played on graphs and hypergraphs. The subject of positional games is strongly related to several other branches of combinatorics such as Ramsey theory, extremal graph and set theory, and the probabilistic method. These notes cover a variety of topics in positional games, including both classical results and recent important developments. They are presented in an accessible way and are accompanied by exercises of varying difficulty, helping the reader to better understand the theory. The text will benefit both researchers and graduate students in combinatorics and adjacent fields.

  13. Beam halo in high-intensity beams

    International Nuclear Information System (INIS)

    In space-charge dominated beams the nonlinear space-charge forces produce a filamentation pattern, which in projection to the 2-D phase spaces results in a 2-component beam consisting of an inner core and a diffuse outer halo. The beam-halo is of concern for a next generation of cw, high-power proton linacs that could be applied to intense neutron generators for nuclear materials processing. The author describes what has been learned about beam halo and the evolution of space-charge dominated beams using numerical simulations of initial laminar beams in uniform linear focusing channels. Initial results are presented from a study of beam entropy for an intense space-charge dominated beam

  14. Beam imaging sensor

    Energy Technology Data Exchange (ETDEWEB)

    McAninch, Michael D.; Root, Jeffrey J.

    2016-07-05

    The present invention relates generally to the field of sensors for beam imaging and, in particular, to a new and useful beam imaging sensor for use in determining, for example, the power density distribution of a beam including, but not limited to, an electron beam or an ion beam. In one embodiment, the beam imaging sensor of the present invention comprises, among other items, a circumferential slit that is either circular, elliptical or polygonal in nature.

  15. Positive psychotherapy.

    Science.gov (United States)

    Seligman, Martin E P; Rashid, Tayyab; Parks, Acacia C

    2006-11-01

    Positive psychotherapy (PPT) contrasts with standard interventions for depression by increasing positive emotion, engagement, and meaning rather than directly targeting depressive symptoms. The authors have tested the effects of these interventions in a variety of settings. In informal student and clinical settings, people not uncommonly reported them to be "life-changing." Delivered on the Web, positive psychology exercises relieved depressive symptoms for at least 6 months compared with placebo interventions, the effects of which lasted less than a week. In severe depression, the effects of these Web exercises were particularly striking. This address reports two preliminary studies: In the first, PPT delivered to groups significantly decreased levels of mild-to-moderate depression through 1-year follow-up. In the second, PPT delivered to individuals produced higher remission rates than did treatment as usual and treatment as usual plus medication among outpatients with major depressive disorder. Together, these studies suggest that treatments for depression may usefully be supplemented by exercises that explicitly increase positive emotion, engagement, and meaning. ((c) 2006 APA, all rights reserved). PMID:17115810

  16. Positively Adolescent!

    Science.gov (United States)

    Williamson, Sue

    2000-01-01

    Believes that music teachers should reassess their views toward adolescent behavior in the music classroom by learning to see their behavior in a positive light. Describes teaching strategies that build on four adolescent behaviors: (1) desire for peer acceptance; (2) abundant energy; (3) love of fun; and (4) limited time-managing skills. (CMK)

  17. First years experience of LHC Beam Instrumentation

    CERN Document Server

    Jones, O R

    2011-01-01

    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. This paper will comment on all of these systems and on their contributions to the various stages of beam commissioning. It will include details on: the beam position system and its use for realtime global orbit feedback; the beam loss system and its role in machine protection; total and bunch by bunch intensity measurements; tune measurement and feedback; synchrotron light 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.

  18. A laser tube position regulator

    Energy Technology Data Exchange (ETDEWEB)

    Sinyitiro, A.; Norio, K.

    1984-03-26

    An improved design is patented for a mechanism and method of regulating, with a high degree of accuracy, the position of a laser tube in a gas laser inside the optical resonator formed by external mirrors. The laser tube is held in two holders. Each holder contains an L shaped bracket which supports a semitransparent plate. The plate is positioned so that its center is over the center of the end of the tube which is in the form of a Brewster window. A narrow parallel beam is directed along the tube axis from an external auxiliary laser. The beam passes through the semitransparent mirror of the optical resonator in the adjusted laser, through the first Brewster window, the tube itself, and the second Brewster window and is reflected back in the reverse direction from a fully reflecting mirror in the optical resonator. This provides partial reflection of the beam from the external Brewster mirror surface. The tube position in the holders is regulated continuously so that the luminous spots from the beams reflected off the Brewster windows fall on the semitransparent plates in the center of the latter which is designated as the point of intersection.

  19. Beam Instrumentation Global Network [BIGNET]: a common web portal for Beam instrumentalists

    CERN Document Server

    Gras, J-J

    2012-01-01

    This document will present an initiative launched during the International Particle Accelerator Conference (IPAC11) to define and produce a common web portal for Beam Instrumentation, with the aim of allowing any beam instrumentalist to easily and efficiently: - find the laboratories with machines using beams of similar characteristics (particle type, total beam intensity, bunch intensity, frequency, energy) - find the person who is working there on the beam observable concerned (i.e. beam position, loss, intensity, transverse or longitudinal profile, tune) and how to contact him/her - create discussion forums with the right audience on hot beam instrumentation topics or issues - advertise topical events and workshop - provide links towards documents describing system designs and performance assessments... This document will cover the status and prospects of the project with the aim to invite and welcome new laboratories to join the adventure.

  20. Composite vortex beams by coaxial superposition of Laguerre-Gaussian beams

    Science.gov (United States)

    Huang, Sujuan; Miao, Zhuang; He, Chao; Pang, Fufei; Li, Yingchun; Wang, Tingyun

    2016-03-01

    We propose the generation of novel composite vortex beams by coaxial superposition of Laguerre-Gaussian (LG) beams with common waist position and waist parameter. Computer-generated holography by conjugate-symmetric extension is applied to produce the holograms of several composite vortex beams. Utilizing the holograms, fantastic light modes including optical ring lattice, double dark-ring and double bright-ring composite vortex beams etc. are numerically reconstructed. The generated composite vortex beams show diffraction broadening with some of them showing dynamic rotation around beam centers while propagating. Optical experiments based on a computer-controlled spatial light modulator (SLM) verify the numerical results. These novel composite vortex beams possess more complicated distribution and more controllable parameters for their potential application in comparison to conventional optical ring lattice.

  1. Beam control and Dosimetry in Proton Therapy

    International Nuclear Information System (INIS)

    This thesis deals with beam control devices for scanned proton beams. The IBA society (Ion Beam Applications) has developed a new dynamic beam delivery system called Pencil Beam Scanning. IBA needed a monitor unit to equip its proton beam lines dedicated to the PBS system and called upon the medical applications group of the Laboratoire de Physique Corpusculaire de Caen. In 2008, this group realized, in collaboration with IBA, an ionization chamber monitor IC2/3 for the IBA dedicated PBS nozzle. This device verifies the agreement between planned and delivered particular fluence. The first part of this thesis focused on the characterization of this monitor unit. Proton beams of different clinical energies, positions and dose rates were used to check the specifications requested by IBA. After the introduction about the Proton Therapy, the validation step of IC2/3 is exposed. Information provided by IC2/3 makes it possible beam control in terms of fluence but does not ensure quality control in terms of spatial dose distribution. The second part of the work was devoted to the conception of a beam control device for scanned proton beams. Called Compass PT, it will allow a reconstruction of the spatial dose distribution delivered to the patient. The specifications definition and the conception studies are presented in this thesis. All this work has led to recommendations for the realization of this device and new research prospects. (author)

  2. Simple Low-Frequency Beam Pickup

    Energy Technology Data Exchange (ETDEWEB)

    Novokhatski, A.; Heifets, S.; /SLAC; Aleksandrov, A.; /Oak Ridge

    2011-10-12

    Detection of the field induced by a beam outside of the beam pipe can be used as a beam diagnostic. Wires placed in longitudinal slots in the outside wall of the beam pipe can be used as a beam pickup. This has a very small beam-coupling impedance and avoids complications of having a feedthrough. The signal can be reasonably high at low frequencies. We present a field waveform at the outer side of a beam pipe, obtained as a result of calculations and measurements. We calculate the beam-coupling impedance due to a long longitudinal slot in the resistive wall and the signal induced in a wire placed in such a slot and shielded by a thin screen from the beam. These results should be relevant for impedance calculations of the slot in an antechamber and for slots in the PEP-II distributed ion pump screens. The design of the low-frequency beam position monitor is very simple. It can be used in storage rings, synchrotron light sources, and free electron lasers, like LINAC coherent light source.

  3. Position sensor

    Science.gov (United States)

    Auer, Siegfried (Inventor)

    1988-01-01

    A radiant energy angle sensor is provided wherein the sensitive portion thereof comprises a pair of linear array detectors with each detector mounted normal to the other to provide X and Y channels and a pair of slits spaced from the pair of linear arrays with each of the slits positioned normal to its associated linear array. There is also provided electrical circuit means connected to the pair of linear array detectors and to separate X and Y axes outputs.

  4. A symplectic coherent beam-beam model

    International Nuclear Information System (INIS)

    We consider a simple one-dimensional model to study the effects of the beam-beam force on the coherent dynamics of colliding beams. The key ingredient is a linearized beam-beam kick. We study only the quadrupole modes, with the dynamical variables being the 2nd-order moments of the canonical variables q, p. Our model is self-consistent in the sense that no higher order moments are generated by the linearized beam-beam kicks, and that the only source of violation of symplecticity is the radiation. We discuss the round beam case only, in which vertical and horizontal quantities are assumed to be equal (though they may be different in the two beams). Depending on the values of the tune and beam intensity, we observe steady states in which otherwise identical bunches have sizes that are equal, or unequal, or periodic, or behave chaotically from turn to turn. Possible implications of luminosity saturation with increasing beam intensity are discussed. Finally, we present some preliminary applications to an asymmetric collider. 8 refs., 8 figs

  5. Initial alignment method for free space optics laser beam

    Science.gov (United States)

    Shimada, Yuta; Tashiro, Yuki; Izumi, Kiyotaka; Yoshida, Koichi; Tsujimura, Takeshi

    2016-08-01

    The authors have newly proposed and constructed an active free space optics transmission system. It is equipped with a motor driven laser emitting mechanism and positioning photodiodes, and it transmits a collimated thin laser beam and accurately steers the laser beam direction. It is necessary to introduce the laser beam within sensible range of the receiver in advance of laser beam tracking control. This paper studies an estimation method of laser reaching point for initial laser beam alignment. Distributed photodiodes detect laser luminescence at respective position, and the optical axis of laser beam is analytically presumed based on the Gaussian beam optics. Computer simulation evaluates the accuracy of the proposed estimation methods, and results disclose that the methods help us to guide the laser beam to a distant receiver.

  6. A test beam upgrade based on the BEPC-LINAC

    International Nuclear Information System (INIS)

    A total of three beam lines, E1, E2 and E3 have based on the LINAC of BEPC. The E1 beam is to be used for intense slow-positron facility. The E2 is a primary positron or electron beam with an energy of 1.3-1.5 GeV. The E3 is a secondary electron or pion test beam with a momentum can be adjustable continuously. The position accuracy of a detected particle is 0.2-0.4 mm with an event rate of 3 - 4 Hz. This beam has been successfully used for some detectors beam test. (author)

  7. Positive Psychologists on Positive Constructs

    Science.gov (United States)

    Lyubomirsky, Sonja

    2012-01-01

    Comments on the original article by McNulty and Fincham (see record 2011-15476-001). In their article, the authors offered compelling evidence that constructs such as forgiveness and optimism can have both beneficial and adverse consequences, depending on the context. Their caution about labeling particular psychological processes as "positive" is…

  8. Beam Measurements in Storage Rings

    Science.gov (United States)

    Hofmann, Albert

    1996-05-01

    Beam measurements in storage rings are made to diagnose performance limitations and to gain knowledge of the beam behavior in view of improvements and to the benefit for other machines. In beam optics the measurement of the orbit or the trajectory with beam position monitors distributed around the ring reveals deflection errors. The overall focusing is checked by measuring the betatron frequency (tune) using a pulse or continuous excitation of the oscillation. Observing this oscillation with all the beam position monitors around the ring the beta function and the betatron phase advance are obtained. This measurement done for different momenta, i.e. RF-frequencies, gives the local chromaticity and its correction. The tune dependence on quadrupole strength gives the value of the local beta function. Synchrotron radiation is a powerful diagnostics tool and can give the beam cross section. Beam instabilities are investigated with similar methods. The growth or damping rates and frequencies of betatron and synchrotron oscillations, observed as a function of intensity, give a convolution of the resistive and reactive part of the transverse and longitudinal impedance with the spectrum of the oscillation mode. Coupled bunch instabilities are caused by narrow band impedances at particular frequencies while single traversal effects, including energy loss and bunch lengthening, are due to a broad band impedance. A model of the impedance can be constructed from such measurements done with different bunch lengths, tunes and other parameters. In some cases the element causing an instability can be identified. The dependence of the orbit and phase advance around the ring on intensity can give the location of impedances. To probe the impedance at very high frequencies the effects on very short bunches or the energy loss of a continuous beam due to its Schottky noise are measured. The beam energy, usually known from magnetic measurements, can be obtained directly with high

  9. Telecommunication using muon beams

    Science.gov (United States)

    Arnold, Richard C.

    1976-01-01

    Telecommunication is effected by generating a beam of mu mesons or muons, varying a property of the beam at a modulating rate to generate a modulated beam of muons, and detecting the information in the modulated beam at a remote location.

  10. LHC beam dumping system Extraction channel layout and acceptance

    CERN Document Server

    Goddard, B; Uythoven, J; Veness, R; Weterings, W

    2003-01-01

    The LHC beam dumping system must safely abort the LHC beams under all conditions, including those resulting from abnormal behaviour of machine elements or subsystems of the beam dumping system itself. The extraction channels must provide sufficient aperture both for the circulating and extracted beams, over the whole energy range and under various beam parameters. These requirements impose tight constraints on the tolerances of various extraction channel components, and also on the allowed range of beam positions in the region of these components. Operation of the beam dumping system under various fault states has been considered, and the resulting apertures calculated. After describing briefly the beam dumping system and the extraction channel geometry, the various assumptions made in the analysis are presented, before deriving tolerance limits for the relevant equipment and beam parameters.

  11. Researcher Positioning

    DEFF Research Database (Denmark)

    Khawaja, Iram; Mørck, Line Lerche

    2009-01-01

    , of membership in a minoritised1 or majoritisedgroup, and the influence of different theoretical and methodological outlooks on ourcommon goal of trying to transcend existing othering and objectifying representationsof Muslims in Western societies. This process sometimes entails a direct political andpersonal...... involvement by the researcher, which challenges traditional perspectives onresearch and researcher positioning. A key point in this regard is the importance ofconstant awareness of and reflection on the multiple ways in which one's positioningas a researcher influences the research process. Studying the other...

  12. The beam dump tunnels

    CERN Multimedia

    Patrice Loïez

    2002-01-01

    In these images workers are digging the tunnels that will be used to dump the counter-circulating beams. Travelling just a fraction under the speed of light, the beams at the LHC will each carry the energy of an aircraft carrier travelling at 12 knots. In order to dispose of these beams safely, a beam dump is used to extract the beam and diffuse it before it collides with a radiation shielded graphite target.

  13. Parabolic scaling beams.

    Science.gov (United States)

    Gao, Nan; Xie, Changqing

    2014-06-15

    We generalize the concept of diffraction free beams to parabolic scaling beams (PSBs), whose normalized intensity scales parabolically during propagation. These beams are nondiffracting in the circular parabolic coordinate systems, and all the diffraction free beams of Durnin's type have counterparts as PSBs. Parabolic scaling Bessel beams with Gaussian apodization are investigated in detail, their nonparaxial extrapolations are derived, and experimental results agree well with theoretical predictions.

  14. Ion beam diagnosis

    International Nuclear Information System (INIS)

    This report is an introduction to ion beam diagnosis. After a short description of the most important ion beam parameters measurements of the beam current by means of Faraday cups, calorimetry, and beam current transformers and measurements of the beam profile by means of viewing screens, profile grids and scanning devices, and residual gas ionization monitors are described. Finally measurements in the transverse and longitudinal phase space are considered. (HSI)

  15. Beam induced heating

    CERN Document Server

    Salvant, B; Arduini, G; Assmann, R; Baglin, V; Barnes, M J; Baudrenghien, P; Bracco, C; Bruce, R; Bertarelli, A; Carra, F; Cattenoz, G; Caspers, F; Claudet, S; Day, H; Esteban Mueller, J; Gentini, L; Goddar, B; Grudiev, A; Henrist, B; Jones, R; Lanza, G; Lari, L; Mastoridis, T; Métral, E; Mounet, N; Nougaret, J L; Piguiet, A M; Redaelli, S; Roncarolo, F; Rumolo, G; Sapinski, M; Shaposhinkova, E; Tavian, L; Timmins, M; Uythoven, J; Vidal, A; Wollmann, D

    2012-01-01

    In 2011, the rapid increase of the luminosity performance of LHC came at the expense of increased temperature and pressure readings on several near-beam LHC equipments. In some cases, this beam induced heating was suspected to cause beam dumps and even degradation of the equipment. This contribution aims at gathering the observations of beam induced heating due to beam coupling impedance, their current level of understanding and possible actions that could be implemented during the winter stop 2011-2012.

  16. Ion-optically driven depth compensation for ion beam tracking

    International Nuclear Information System (INIS)

    The beam delivery system for scanned carbon ion beam radiotherapy at GSI has been extended in research mode to irradiate moving targets. For beam tracking, the ion beam is adapted laterally as well as in range corresponding to the target's three dimensional (3D) motion. A beam tracking system with a motorized double wedge system for fast and accurate range adaptation has been developed. In addition to the current range adaptation system a much faster method for online energy modulation is being investigated where a fine focused ion beam is dynamically positioned, controlled by fast dipole magnets, on a small static wedge shaped absorber within the beam line. Experiments were performed at the therapy beam line to study the beam shift from central axis by the first dipole magnet up to the maximum limit where the beam can be deflected back to central axis by the second dipole magnet. Beam profiles were measured at different locations of the beam delivery system. The particle transmission was measured as well at the target position. Experiments were supported by Monte Carlo simulations for energy variation studies and for assessing the influence on beam profiles using MOCADI code

  17. Influence of laser array performance on spectrally combined beam

    Science.gov (United States)

    Wu, Zhen; Yang, Lei; Zhong, Zheqiang; Zhang, Bin

    2016-10-01

    Incoherent spectral beam combining (SBC) of multiple laser beams is accomplished along the emitters' arraying direction. Considering that the output beams from a laser array (LA) usually have deflection angles, positional displacements and divergence angles even after being collimated, a propagation model of SBC systems based on multilayer dielectric gratings has been built up. On the basis, properties of the spectrally combined beam affected by parameters of the LA have been discussed in detail. Simulation results show that with the increase in the deflection angle, both the power and the beam quality of the combined beam degrade dramatically. The positional displacement has little impact on the intensity distribution and the beam quality of combined beam but change the wavelength composition of the combined beam. The divergence angle strongly affects the intensity distribution and the beam quality of the combined beam. Additionally, the effect of the deflection angle on the output beam quality is more obvious and may shift the beam spot when comparing with that of the divergence angle.

  18. Beam Parameter Measurement and Control at the SNS Target

    CERN Document Server

    Plum, Michael; McManamy, Tom

    2005-01-01

    The spallation neutron production target at the SNS facility is designed for 1.4 MW beam power. Both beam position and profile must be carefully controlled within narrow margins to avoid damage to the target. The position must be within 2 mm of the target center, and 90% of the beam must be within the nominal 70 mm x 200 mm spot size, without exceeding 0.18 A/m2

  19. ILC Beam Energy Measurement by means of Laser Compton Backscattering

    OpenAIRE

    Muchnoi, N.; Schreiber, H. J.; Viti, M

    2008-01-01

    A novel, non-invasive method of measuring the beam energy at the International Linear Collider is proposed. Laser light collides head-on with beam particles and either the energy of the Compton scattered electrons near the kinematic end-point is measured or the positions of the Compton backscattered $\\gamma$-rays, the edge electrons and the unscattered beam particles are recorded. A compact layout for the Compton spectrometer is suggested. It consists of a bending magnet and position sensitiv...

  20. wPosition of mandibular canal determined by Cone-beam computed tomography examination in 83 Chinese people%锥形束CT对83例中国人下颌神经管的位置测量研究

    Institute of Scientific and Technical Information of China (English)

    王朝; 徐淑兰; 周磊; 姚钟雄; 杨烁; 钟丹霞

    2014-01-01

    目的:探究下颌神经管与下颌骨的位置关系,为种植及植骨手术提供理论依据。方法:收集83名中国人下颌神经管的锥形束CT扫描数据,对其双侧下颌神经管的数据进行测量分析。结果:下颌神经管到下颌骨颊侧壁的距离为(5.32±1.29)~(7.24±1.29)mm,到下颌骨舌侧壁的平均距离为(3.43±0.99)~(3.93±1.17)mm,到下颌骨下缘的平均距离为(8.81±1.90)~(10.02±2.19)mm,内径的平均值为(2.27±0.44)~(2.61±0.40)mm。男性与女性在下颌管距下颌骨颊侧壁、下颌下缘以及下颌骨内径的平均值上差异有显著性(P<0.05)。前襻的出现率是70.9%,长度为(2.76±1.14)mm。下颌管分支的出现率为10.84%,长度为(10.72±5.29)mm。结论:中国人下颌管在下颌骨内的位置变异较大,前襻和下颌管分支在下颌骨中发生率较高,植骨及种植手术前应仔细检查,减小神经损伤的风险。%Objective To analyse the location of the mandibular canal,providing the theoretical basis for implanting and bone grafting. Methods Mandibular data of 83 Chinese people obtained by cone-beam computed tomography examination were collected. Results The distance from the mandibular canal to mandibular buccal wall was (5.32 ± 1.29)~(7.24 ± 1.29) mm. And the average distance from mandibular canal to mandibular lingual wall or inferior margin were respectively (3.43 ± .99) ~ (3.93 ± 1.17) mm and (8.81 ± 1.90) ~ (10.02 ± 2.19) mm. Significant differences between males and females were found in groups. The anterior loop was observed in 70.9%of all sides. The accessory mental foramen was observed in 10.84% of all sides. Conclusion For the remarkable mutation of the location of the mandibular canal in Chinese people, clinicians should be careful before implant or bone surgery procedures to minimize the risk of inferior alveolar

  1. Off-axis beam quality change in linear accelerator x-ray beams

    International Nuclear Information System (INIS)

    The effective energy of the x-ray beam from linear accelerators changes as a function of the position in the beam due to nonuniform filtration by the flattening filter. In this work, the transmittance through a water column was measured in good geometry and the beam quality characterized in units of HVL in water. Measurements were made on a variety of linear accelerators from 4 to 10 MV. The beam energy decreased with increasing distance from the central ray for all accelerators measured

  2. Wavefront dislocations of Gaussian beams nesting optical vortices in a turbulent atmosphere

    Institute of Scientific and Technical Information of China (English)

    Yixin Zhang(张逸新); Chunkan Tao(陶纯堪)

    2004-01-01

    A phase singularity of the light field created by interference of two Gaussian singular beams which propagate in a weak and near ground turbulent atmosphere is analyzed by the Rytov approximation and the short-term averaging method of the dislocation-position. We demonstrate that an edge or circular dislocation may be formed by both parallel and coaxial or noncoaxial collimated beams with different or equal beam-width interfere. The edge or circular short-term wavefront dislocations of super position field depend on the atmospheric turbulence strength, beam propagation distance, amplitude ratio, dislocation of nesting vortices, and beam-width or beam-width ratio of the individual beams.

  3. 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.

  4. Application of Beam Diagnostics for Intense Heavy Ion Beams at the GSI UNILAC

    CERN Document Server

    Barth, W; Glatz, J; Groening, L; Richter, S; Yaramishev, S

    2003-01-01

    With the new High Current Injector (HSI) of the GSI UNILAC the beam pulse intensity had been increased by approximately two orders of magnitudes. The HSI was mounted and commissioned in 1999; since this time the UNILAC serves as an injector for the synchrotron SIS, especially for high uranium intensities. Considering the high beam power of up to 1250 kW and the short stopping range for the UNILAC beam energies (≤12 MeV/u), accelerator components could be destroyed, even during a single beam pulse. All diagnostic elements had to be replaced preferably by non-destructive devices. The beam current is mainly measured by beam transformers instead of Faraday cups, beam positions are measured with segmented capacitive pick-ups and secondary beam monitors instead of profile harps. The 24 installed pick-ups are also used to measure intensities, widths and phase of the bunches, as well beam energies by evaluating pick-ups at different positions. The residual gas ionization monitors allow on-line measurements ...

  5. Omega spectrometer ready for SPS beams

    CERN Multimedia

    1977-01-01

    Two different beams arrive into the Omega magnet: - a tagged photon beam for a charm search - experiment WA4 by the Bonn-CERN-Daresbury-Ecole Polytechnique-Glasgow-Lancaster-Manchester-Orsay-Sheffield Collaboration; - a separated hadron beam, at first for a beam-dump experiment - WA12 by the Birmingham-CERN-Ecole Polytechnique-MPI, Munich-Neuchâtel Collaboration. Beams of either negative or positive pions or kaons, protons or antiprotons, all at an energy around 40 GeV were made to impinge on a copper target where a shower of hadrons was produced and, on occasion, two muons which before detection passed through an iron absorber (not visible here). WA12 was completed in February 1977. At the centre, on top of the superconducting magnet, the hut containing the TV cameras, These observe the particle events occurring in the spark chambers in the magnet below.

  6. Quality assurance for particle beam therapy

    International Nuclear Information System (INIS)

    In radiation therapy, it is essential that a prescribed target area is irradiated with the prescribed dose concentration to reduce the possibility cancer reoccurrence or to mitigate its side effects. Particle beam therapy is a high accuracy radiation therapy, which has superior characteristics. Specifically, a high dose region, namely, Bragg peak formed around the beam stopping point can be adjusted to the target volume. The routine of particle beam therapy should be performed with various verifications, called quality assurance(QA), at its each step, i.e., treatment planning, dosimetry, patient positioning and respiratory gating system. Each particle beam therapy facility should have and conduct its own QA program. Methods and materials for the QA should be developed according to the progress of techniques in particle beam therapy. (author)

  7. Electron Beam Lithography for nano-patterning

    DEFF Research Database (Denmark)

    Greibe, Tine; Anhøj, Thomas Aarøe; Khomtchenko, Elena;

    2014-01-01

    Electron beam lithography is a versatile tool for fabrication of nano-sized patterns. The patterns are generated by scanning a focused beam of high-energy electrons onto a substrate coated with a thin layer of electron-sensitive polymer (resist), i.e. by directly writing custom-made patterns...... in a polymer. Electron beam lithography is a suitable method for nano-sized production, research, or development of semiconductor components on a low-volume level. Here, we present electron beam lithography available at DTU Danchip. We expertize a JEOL 9500FZ with electrons accelerated to an energy of 100ke...... are mounted on a stage which is positionally controlled by laserinterferometry. This results in a resolution of 10 nm and stitching accuracy of 10 nm. The electron beam writer is located in a class 10 (ISO 4) cleanroom which is vibrationally and electromagnetically screened from the surroundings. Furthermore...

  8. Pyramid beam splitter

    Science.gov (United States)

    McKeown, Mark H.; Beason, Steven C.; Fairer, George

    1992-01-01

    The apparatus of the present invention provides means for obtaining accurate, dependable, measurement of bearings and directions for geologic mapping in subterranean shafts, such as, for example, nuclear waste storage investigations. In operation, a laser beam is projected along a reference bearing. A pyramid is mounted such that the laser beam is parallel to the pyramid axis and can impinge on the apex of the pyramid thus splitting the beam several ways into several beams at right angles to each other and at right angles to the reference beam. The pyramid is also translatable and rotatable in a plane perpendicular to the reference beam.

  9. Low current beam techniques

    Energy Technology Data Exchange (ETDEWEB)

    Saint, A.; Laird, J.S.; Bardos, R.A.; Legge, G.J.F. [Melbourne Univ., Parkville, VIC (Australia). School of Physics; Nishijima, T.; Sekiguchi, H. [Electrotechnical Laboratory, Tsukuba (Japan).

    1993-12-31

    Since the development of Scanning Transmission Microscopy (STIM) imaging in 1983 many low current beam techniques have been developed for the scanning (ion) microprobe. These include STIM tomography, Ion Beam Induced Current, Ion Beam Micromachining and Microlithography and Ionoluminense. Most of these techniques utilise beam currents of 10{sup -15} A down to single ions controlled by beam switching techniques This paper will discuss some of the low beam current techniques mentioned above, and indicate, some of their recent applications at MARC. A new STIM technique will be introduced that can be used to obtain Z-contrast with STIM resolution. 4 refs., 3 figs.

  10. Quantifying the Reproducibility of Heart Position During Treatment and Corresponding Delivered Heart Dose in Voluntary Deep Inhalation Breath Hold for Left Breast Cancer Patients Treated With External Beam Radiotherapy

    International Nuclear Information System (INIS)

    Purpose: Voluntary deep inhalation breath hold (VDIBH) reduces heart dose during left breast irradiation. We present results of the first study performed to quantify reproducibility of breath hold using bony anatomy, heart position, and heart dose for VDIBH patients at treatment table. Methods and Materials: Data from 10 left breast cancer patients undergoing VDIBH whole-breast irradiation were analyzed. Two computed tomography (CT) scans, free breathing (FB) and VDIBH, were acquired to compare dose to critical structures. Pretreatment weekly kV orthogonal images and tangential ports were acquired. The displacement difference from spinal cord to sternum across the isocenter between coregistered planning Digitally Reconstructed Radiographs (DRRs) and kV imaging of bony thorax is a measure of breath hold reproducibility. The difference between bony coregistration and heart coregistration was the measured heart shift if the patient is aligned to bony anatomy. Results: Percentage of dose reductions from FB to VDIBH: mean heart dose (48%, SD 19%, p = 0.002), mean LAD dose (43%, SD 19%, p = 0.008), and maximum left anterior descending (LAD) dose (60%, SD 22%, p = 0.008). Average breath hold reproducibility using bony anatomy across the isocenter along the anteroposterior (AP) plane from planning to treatment is 1 (range, 0–3; SD, 1) mm. Average heart shifts with respect to bony anatomy between different breath holds are 2 ± 3 mm inferior, 1 ± 2 mm right, and 1 ± 3 mm posterior. Percentage dose changes from planning to delivery: mean heart dose (7%, SD 6%); mean LAD dose, ((9%, SD 7%)S, and maximum LAD dose, (11%, SD 11%) SD 11%, p = 0.008). Conclusion: We observed excellent three-dimensional bony registration between planning and pretreatment imaging. Reduced delivered dose to heart and LAD is maintained throughout VDIBH treatment.

  11. Quantifying the Reproducibility of Heart Position During Treatment and Corresponding Delivered Heart Dose in Voluntary Deep Inhalation Breath Hold for Left Breast Cancer Patients Treated With External Beam Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    McIntosh, Alyson; Shoushtari, Asal N.; Benedict, Stanley H.; Read, Paul W. [Department of Radiation Oncology, University of Virginia, Charlottesville, Virginia (United States); Wijesooriya, Krishni, E-mail: kw5wx@virginia.edu [Department of Radiation Oncology, University of Virginia, Charlottesville, Virginia (United States)

    2011-11-15

    Purpose: Voluntary deep inhalation breath hold (VDIBH) reduces heart dose during left breast irradiation. We present results of the first study performed to quantify reproducibility of breath hold using bony anatomy, heart position, and heart dose for VDIBH patients at treatment table. Methods and Materials: Data from 10 left breast cancer patients undergoing VDIBH whole-breast irradiation were analyzed. Two computed tomography (CT) scans, free breathing (FB) and VDIBH, were acquired to compare dose to critical structures. Pretreatment weekly kV orthogonal images and tangential ports were acquired. The displacement difference from spinal cord to sternum across the isocenter between coregistered planning Digitally Reconstructed Radiographs (DRRs) and kV imaging of bony thorax is a measure of breath hold reproducibility. The difference between bony coregistration and heart coregistration was the measured heart shift if the patient is aligned to bony anatomy. Results: Percentage of dose reductions from FB to VDIBH: mean heart dose (48%, SD 19%, p = 0.002), mean LAD dose (43%, SD 19%, p = 0.008), and maximum left anterior descending (LAD) dose (60%, SD 22%, p = 0.008). Average breath hold reproducibility using bony anatomy across the isocenter along the anteroposterior (AP) plane from planning to treatment is 1 (range, 0-3; SD, 1) mm. Average heart shifts with respect to bony anatomy between different breath holds are 2 {+-} 3 mm inferior, 1 {+-} 2 mm right, and 1 {+-} 3 mm posterior. Percentage dose changes from planning to delivery: mean heart dose (7%, SD 6%); mean LAD dose, ((9%, SD 7%)S, and maximum LAD dose, (11%, SD 11%) SD 11%, p = 0.008). Conclusion: We observed excellent three-dimensional bony registration between planning and pretreatment imaging. Reduced delivered dose to heart and LAD is maintained throughout VDIBH treatment.

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

    CERN Document Server

    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.

  13. 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.

  14. Beam-beam issues in asymmetric colliders

    Energy Technology Data Exchange (ETDEWEB)

    Furman, M.A.

    1992-07-01

    We discuss generic beam-beam issues for proposed asymmetric e{sup +}- e{sup -} colliders. We illustrate the issues by choosing, as examples, the proposals by Cornell University (CESR-B), KEK, and SLAC/LBL/LLNL (PEP-II).

  15. Beam Test Results of High Q CBPM prototype for SXFEL

    CERN Document Server

    Chen, Jian; Yu, Luyang; Lai, Longwei; Yuan, Renxian

    2016-01-01

    Aiming at high precision beam position measurement of micron or sub-micron for Shanghai Soft X-ray free electron laser (SXFEL) facility which is being built in site of the Shanghai Synchrotron Radiation Facility (SSRF), Shanghai Institute of Applied Physics has developed a high Q cavity beam position monitor (CBPM) that the resonant frequency is 4.7 GHz and relevant BPM electronics include dedicated RF front-end and home-made digital BPM (DBPM) also has been done. The cavity design, cold test, system architecture and the beam test with three adjacent pickups has been performed in Shanghai Deep ultraviolet free electron laser(SDUV-FEL) facility are included. The beam experiment results show that the physical design of our CBPM is consistent with the expectations basically and the beam position resolution can fulfill the resolution requirements for the SXFEL project if we optimize the beam conditions.

  16. Beam-Forming Concentrating Solar Thermal Array Power Systems

    Science.gov (United States)

    Cwik, Thomas A. (Inventor); Dimotakis, Paul E. (Inventor); Hoppe, Daniel J. (Inventor)

    2016-01-01

    The present invention relates to concentrating solar-power systems and, more particularly, beam-forming concentrating solar thermal array power systems. A solar thermal array power system is provided, including a plurality of solar concentrators arranged in pods. Each solar concentrator includes a solar collector, one or more beam-forming elements, and one or more beam-steering elements. The solar collector is dimensioned to collect and divert incoming rays of sunlight. The beam-forming elements intercept the diverted rays of sunlight, and are shaped to concentrate the rays of sunlight into a beam. The steering elements are shaped, dimensioned, positioned, and/or oriented to deflect the beam toward a beam output path. The beams from the concentrators are converted to heat at a receiver, and the heat may be temporarily stored or directly used to generate electricity.

  17. Beam transport and space charge compensation strategies (invited)

    Energy Technology Data Exchange (ETDEWEB)

    Meusel, O., E-mail: o.meusel@iap.uni-frankfurt.de; Droba, M.; Noll, D.; Schulte, K.; Schneider, P. P.; Wiesner, C. [IAP, Goethe University Frankfurt, Frankfurt D-60438 (Germany)

    2016-02-15

    The transport of intense ion beams is affected by the collective behavior of this kind of multi-particle and multi-species system. The space charge expressed by the generalized perveance dominates the dynamical process of thermalisation, which leads to emittance growth. To prevent changes of intrinsic beam properties and to reduce the intensity dependent focusing forces, space charge compensation seems to be an adequate solution. In the case of positively charged ion beams, electrons produced by residual gas ionization and secondary electrons provide the space charge compensation. The influence of the compensation particles on the beam transport and the local degree of space charge compensation is given by different beam properties as well as the ion beam optics. Especially for highly charged ion beams, space charge compensation in combination with poor vacuum conditions leads to recombination processes and therefore increased beam losses. Strategies for providing a compensation-electron reservoir at very low residual gas pressures will be discussed.

  18. Laser-Beam Separator

    Science.gov (United States)

    Mcdermid, I. S.

    1984-01-01

    Train of prisms and optical stop separate fundamental beam of laser from second and higher order harmonics of beam produced in certain crystals and by stimulated Raman scattering in gases and liquids.

  19. 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.

  20. Space charge dominated beams

    International Nuclear Information System (INIS)

    After an introductory section on the relationship between emittance and beam Coulomb energy we discuss the properties of space charge dominated beams in progressive steps: from uniformly charged bunched beams to non-uniformly charged beams to correlation effects between particles (simulation beams or 'crystalline' beams). A practical application can be found in the beam dynamics of a high-current injector. The concept of correlation energy is of practical interest in computer simulation of high-brilliance beams, where one deals with an artificially enhanced two-particle Coulomb energy, if many real particles are combined into one simulation super-particle. This can be a source of non-physical emittance growth. (orig./HSI)

  1. High energy beam lines

    Science.gov (United States)

    Marchetto, M.; Laxdal, R. E.

    2014-01-01

    The ISAC post accelerator comprises an RFQ, DTL and SC-linac. The high energy beam lines connect the linear accelerators as well as deliver the accelerated beams to two different experimental areas. The medium energy beam transport (MEBT) line connects the RFQ to the DTL. The high energy beam transport (HEBT) line connects the DTL to the ISAC-I experimental stations (DRAGON, TUDA-I, GPS). The DTL to superconducting beam (DSB) transport line connects the ISAC-I and ISAC-II linacs. The superconducting energy beam transport (SEBT) line connects the SC linac to the ISAC-II experimental station (TUDA-II, HERACLES, TIGRESS, EMMA and GPS). All these lines have the function of transporting and matching the beams to the downstream sections by manipulating the transverse and longitudinal phase space. They also contain diagnostic devices to measure the beam properties.

  2. Slit disk for modified faraday cup diagnostic for determining power density of electron and ion beams

    Science.gov (United States)

    Teruya, Alan T.; Elmer; John W.; Palmer, Todd A.

    2011-03-08

    A diagnostic system for characterization of an electron beam or an ion beam includes an electrical conducting disk of refractory material having a circumference, a center, and a Faraday cup assembly positioned to receive the electron beam or ion beam. At least one slit in the disk provides diagnostic characterization of the electron beam or ion beam. The at least one slit is located between the circumference and the center of the disk and includes a radial portion that is in radial alignment with the center and a portion that deviates from radial alignment with the center. The electron beam or ion beam is directed onto the disk and translated to the at least one slit wherein the electron beam or ion beam enters the at least one slit for providing diagnostic characterization of the electron beam or ion beam.

  3. Proton beam writing

    OpenAIRE

    Frank Watt; Breese, Mark B H; Bettiol, Andrew A; Jeroen A. van Kan

    2007-01-01

    Proton beam (p-beam) writing is a new direct-writing process that uses a focused beam of MeV protons to pattern resist material at nanodimensions. The process, although similar in many ways to direct writing using electrons, nevertheless offers some interesting and unique advantages. Protons, being more massive, have deeper penetration in materials while maintaining a straight path, enabling p-beam writing to fabricate three-dimensional, high aspect ratio structures with vertical, smooth side...

  4. Welding by laser beam

    International Nuclear Information System (INIS)

    A laser which does not require a vacuum and the beam from which can be projected over a distance without loss of power is sited outside a welding zone and the beam projected through a replaceable laser transparent window. The window is designed and shaped to facilitate access of the beam of workpiece items to be welded in containment. Either the workpiece or the laser beam may be moved during welding. (author)

  5. Slow kaon beams

    International Nuclear Information System (INIS)

    A short description is given of considerations for the design of low-momentum kaon beam lines. Relevant data for the performance of seven existing and decommissioned slow kaon beams are presented. For single-stage separated beams the observed ratio all/K- is greater than 50 for momenta less than 500 MeV/c. We recommend a two-stage separated beam with perhaps an upstream cleanup section for maximal purity

  6. Beam Dynamics for ARIA

    CERN Document Server

    Ekdahl, Carl

    2015-01-01

    Beam dynamics issues are assessed for a new linear induction electron accelerator being designed for flash radiography of large explosively driven hydrodynamic experiments. Special attention is paid to equilibrium beam transport, possible emittance growth, and beam stability. It is concluded that a radiographic quality beam will be produced possible if engineering standards and construction details are equivalent to those on the present radiography accelerators at Los Alamos.

  7. Electron beam focusing system

    Energy Technology Data Exchange (ETDEWEB)

    Dikansky, N.; Nagaitsev, S.; Parkhomchuk, V.

    1997-09-01

    The high energy electron cooling requires a very cold electron beam. Thus, the electron beam focusing system is very important for the performance of electron cooling. A system with and without longitudinal magnetic field is presented for discussion. Interaction of electron beam with the vacuum chamber as well as with the background ions and stored antiprotons can cause the coherent electron beam instabilities. Focusing system requirements needed to suppress these instabilities are presented.

  8. Beam Dynamics for ARIA

    Energy Technology Data Exchange (ETDEWEB)

    Ekdahl, Carl August Jr. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-10-14

    Beam dynamics issues are assessed for a new linear induction electron accelerator being designed for flash radiography of large explosively driven hydrodynamic experiments. Special attention is paid to equilibrium beam transport, possible emittance growth, and beam stability. It is concluded that a radiographic quality beam will be produced possible if engineering standards and construction details are equivalent to those on the present radiography accelerators at Los Alamos.

  9. Low energy beam transport system developments

    Energy Technology Data Exchange (ETDEWEB)

    Dudnikov, V., E-mail: vadim@muonsinc.com [Muons, Inc., Batavia, IL 60510 (United States); Han, B.; Stockli, M.; Welton, R. [ORNL, Oak Ridge, TN 37831 (United States); Dudnikova, G. [University of Maryland, College Park, MD 3261 (United States); Institute of Computational Technologies SBRAS, Novosibirsk (Russian Federation)

    2015-04-08

    For high brightness beam production it is important to preserve the brightness in the low energy beam transport system (LEBT) used to transport and match the ion beams to the next stage of acceleration, usually an RFQ. While electrostatic focusing can be problematic for high current beam transport, reliable electrostatic LEBT operation has been demonstrated with H{sup −} beams up to 60 mA. Now, however, it is commonly accepted that an optimal LEBT for high current accelerator applications consists of focusing solenoids with space charge compensation. Two-solenoid LEBTs are successfully used for high current (>100 mA) proton beam transport. Preservation of low emittances (~0.15 π mm-mrad) requires the addition of a heavy gas (Xe, Kr), which causes ~5% of proton loss in a 1 m long LEBT. Similar Xe densities would be required to preserve low emittances of H{sup −} beams, but such gas densities cause unacceptably high H{sup −} beam losses. A short LEBT with only one short solenoid, movable for RFQ matching, can be used for reduced negative ion stripping. A strong electrostatic-focusing LEBT has been successfully adopted for transport of high current H{sup −} beams in the SNS Front End. Some modifications of such electrostatic LEBTs are expected to improve the reliable transport of intense positive and negative ion beams without greatly degrading their low emittances. We concentrate on processes that determine the beam brightness degradation and on their prevention. Proposed improvements to the SNS electrostatic LEBT are discussed.

  10. Total body irradiation with a sweeping beam

    Energy Technology Data Exchange (ETDEWEB)

    Pla, M.; Chenery, S.G.; Podgorsak, E.B.

    1983-01-01

    A technique for total body irradiation, in which the patient lies in the prone or supine position in the beam of a conventional column mounted 4 MV linear accelerator, is described. A sufficiently large radiation field is obtained by rotating the beam in a vertical plane about the source (i.e., sweeping beam) at a source-to-skin distance of 190 cm on the vertical axis. The variation of the midplane dose is less than +lt. slash-5% in parallel-opposed beams, when attenuators are placed over the region containing the lungs and bolus is employed around the head and legs. The percentage depth dose for the sweeping beam is identical to that of a stationary beam for the same collimator setting and source-to-skin distance. A method for monitoring the dose to the patient by means of a thimble ionization chamber located on the vertical beam axis is outlined. The average dose rates used are between 5 and 10 cGy/min. The design and placement of lung attenuators is simple. The treatment technique with the sweeping beam requires minimal modification of a treatment unit and can be applied on any unit which has a head swivel option.

  11. Electron beam damage in oxides: a review.

    Science.gov (United States)

    Jiang, Nan

    2016-01-01

    This review summarizes a variety of beam damage phenomena relating to oxides in (scanning) transmission electron microscopes, and underlines the shortcomings of currently popular mechanisms. These phenomena include mass loss, valence state reduction, phase decomposition, precipitation, gas bubble formation, phase transformation, amorphization and crystallization. Moreover, beam damage is also dependent on specimen thickness, specimen orientation, beam voltage, beam current density and beam size. This article incorporates all of these damage phenomena and experimental dependences into a general description, interpreted by a unified mechanism of damage by induced electric field. The induced electric field is produced by positive charges, which are generated from excitation and ionization. The distribution of the induced electric fields inside a specimen is beam-illumination- and specimen-shape- dependent, and associated with the experimental dependence of beam damage. Broadly speaking, the mechanism operates differently in two types of material. In type I, damage increases the resistivity of the irradiated materials, and is thus divergent, resulting in phase separation. In type II, damage reduces the resistivity of the irradiated materials, and is thus convergent, resulting in phase transformation. Damage by this mechanism is dependent on electron-beam current density. The two experimental thresholds are current density and irradiation time. The mechanism comes into effect when these thresholds are exceeded, below which the conventional mechanisms of knock-on and radiolysis still dominate.

  12. Microdosimetry of high LET therapeutic beams

    International Nuclear Information System (INIS)

    Experimental microdosimetry of high LET therapeutic beams were presented. The cyclotron produced fast neutron beams at IMS, TAMVEC and NRL, a reactor fast neutron at YAYOI, a proctor beam at Harvard and a pion beam at TRIUMF are included. Measurements were performed with a conventional tissue equivalent spherical proportional counter with a logarithmic amplifier which made the recording and analysis quite simple. All the energy deposition spectra were analysed in the conventional manner and anti y F, anti y D as well as anti y D* were calculated. The spectra and their mean lineal energies showed wide variations, depending on the particle type, energy, position in phantom. Fractional contribution of elemental particles ( electron, muon, pion, proton, alpha and so on) to the total dose were analysed. For fast neutron beams, the y spectra stayed almost constant at any depth along the central axis in the phantom. The y spectra of proton beam changed slightly along the depth. On the other side, the y spectra of pion beam change drastically in the phantom between plateau and dose peak region. A novel technique of time-of-flight microdosimetry was employed, which made it possible to separate the fractional contribution of contaminant electrons and muons out of pions. Finally, a map of the radiation quality for all the beams is presented and its significances are discussed. (author)

  13. Qualification of electron beam welding procedure

    International Nuclear Information System (INIS)

    In electron beam welding, the problem of the procedure qualification is quite special. The main results obtained are presented namely: the influence of the welding equipment used, the finding of significant testing to be taken into consideration for the process qualification. The experiments have been made using two different welding machines. Two materials have been selected (austenitic stainless steel and ferritic steel) and two welding positions (flat position and horizontal-vertical position) investigated

  14. Beams 92: Proceedings

    International Nuclear Information System (INIS)

    This report contains papers on the following topics: Ion beam papers; electron beam, bremsstrahlung, and diagnostics papers; radiating Z- pinch papers; microwave papers; electron laser papers; advanced accelerator papers; beam and pulsed power applications papers; pulsed power papers; and these papers have been indexed separately elsewhere

  15. Accelerating nondiffracting beams

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Shaohui; Li, Manman; Yao, Baoli, E-mail: yaobl@opt.ac.cn; Yu, Xianghua; Lei, Ming; Dan, Dan; Yang, Yanlong; Min, Junwei; Peng, Tong

    2015-06-05

    We present a set of beams which combine the properties of accelerating beams and (conventional) diffraction-free beams. These beams can travel along a desired trajectory while keeping an approximately invariant transverse profile, which may be (higher-order) Bessel-, Mathieu- or parabolic-nondiffracting-like beams, depending on the initial complex amplitude distribution. A possible application of these beams presented here may be found in optical trapping field. For example, a higher-order Bessel-like beam, which has a hollow (transverse) pattern, is suitable for guiding low-refractive-index or metal particles along a curve. - Highlights: • A set of beams having arbitrary trajectories of accelerating and nondiffracting behaviors are generalized and presented. • Bessel-like accelerating beams are generalized to the higher-order (hollow) version. • Mathieu-like accelerating beams and parabolic-nondiffracting-like accelerating beams are presented. • A possible application of these beams may be found in optical trapping and guiding of particles.

  16. An Electromagnetic Beam Converter

    DEFF Research Database (Denmark)

    2009-01-01

    The present invention relates to an electromagnetic beam converter and a method for conversion of an input beam of electromagnetic radiation having a bell shaped intensity profile a(x,y) into an output beam having a prescribed target intensity profile l(x',y') based on a further development...

  17. Klystron beam bunching

    International Nuclear Information System (INIS)

    A detailed description of electron-beam bunching phenomena in klystrons is presented. Beam harmonic current is defined, both space-charge and ballistic bunching are analyzed, Ramo's theorem is used to describe how a bunched beam drives a cavity, and a general cavity model including external coupling is provided. (author)

  18. Protection and Diagnostic Systems for High Intensity Beams

    CERN Document Server

    Jensen, L; Vismara, Giuseppe

    2000-01-01

    This paper presents a summary of the facilities for beam interlocks and diagnostics to protect the CERN SPS machine. An overview of the existing systems is given, which are based on beam loss and beam current monitors and large beam position excursion in the horizontal plane. The later system mainly protects the system against a failure of the transverse damping system. The design for a new large excursion interlock for both transverse planes is also presented in some detail. For this system a digital approach is being taken to allow post-mortem analysis of the behaviour of the beam prior to the activation of the interlock.

  19. Multiple-beam Propagation in an Anderson Localized Optical Fiber

    CERN Document Server

    Karbasi, Salman; Mafi, Arash

    2012-01-01

    We investigate the simultaneous propagation of multiple beams in a disordered Anderson localized optical fiber. The profiles of each beam fall off exponentially, enabling multiple channels at high-density. We examine the influence of fiber bends on the movement of the beam positions, which we refer to as drift. We investigate the extent of the drift of localized beams induced by macro-bending and show that it is possible to design Anderson localized optical fibers which can be used for practical beam-multiplexing applications.

  20. Energy compensation of slow extracted beams with RF acceleration

    Science.gov (United States)

    Fujimoto, Tetsuya; Souda, Hikaru; Torikoshi, Masami; Kanai, Tatsuaki; Yamada, Satoru; Noda, Koji

    2016-03-01

    In a conventional carbon-ion radiotherapy facility, a carbon-ion beam is typically accelerated up to an optimum energy, slowly extracted from a synchrotron ring by a resonant slow extraction method, and ultimately delivered to a patient through a beam-delivery system. At Japan's Gunma University, a method employing slow-beam extraction along with beam-acceleration has been adopted. This method slightly alters the extracted-beam's energy owing to the acceleration component of the process, which subsequently results in a residual-range variation of approximately 2 mm in water-equivalent length. However, this range variation does not disturb a distal dose distribution with broad-beam methods such as the single beam-wobbling method. With the pencil-beam 3D scanning method, however, such a range variation disturbs a distal dose distribution because the variation is comparable to slice thickness. Therefore, for pencil-beam 3D scanning, an energy compensation method for a slow extracted beam is proposed in this paper. This method can compensate for the aforementioned energy variances by controlling net energy losses through a rotatable energy absorber set fixed between the synchrotron exit channel and the isocenter. Experimental results demonstrate that beam energies can be maintained constant, as originally hypothesized. Moreover, energy-absorber positions were found to be significantly enhanced by optimizing beam optics for reducing beam-size growth by implementation of the multiple-scattering effect option.

  1. Pushing the limits - beam

    CERN Document Server

    Métral, E

    2011-01-01

    Many collective effects were observed in 2010, first when the intensity per bunch was increased and subsequently when the number of bunches was pushed up and the bunch spacing was reduced. After a review of the LHC performance during the 2010 run, with a particular emphasis on impedances and related single-beam coherent instabilities, but mentioning also beam-beam and electron cloud issues, the potential of the LHC for 2011 will be discussed. More specifically, the maximum bunch/beam intensity and the maximum beam brightness the LHC should be able to swallow will be compared to what the injectors can provide.

  2. Cluster ion beam evaporation

    International Nuclear Information System (INIS)

    Cluster ions can be made by the supercooling due to adiabatic expansion of substances to be vaporized which are ejected from a nozzle. This paper is described on the recent progress of studies concerning the cluster beam. The technique of cluster ion beam has been applied for the studies of thermonuclear plasma, the fabrication of thin films, crystal growth and electronic devices. The density of cluster ion beam is larger than that of atomic ion beam, and the formation of thin films can be easily done in high vacuum. This method is also useful for epitaxial growth. Metallic vapour cluster beam was made by the help of jetting rare gas beam. Various beam sources were developed. The characteristics of these sources were measured and analyzed. (Kato, T.)

  3. On the propagation of a low energy oxygen ion beam

    International Nuclear Information System (INIS)

    Positive ion beams, in the range from about tens eV to several hundred eV are frequently used in RIE and RIBE etching systems. The experimental limitations in this energy range are severe and there are still many unsolved problems. Optimal ion beam focusing and maximum current beam at the substrate target are assured by the adequate ion beam neutralization. The electrons from the target plasma and also the secondary ones resulted from the ion-grid and ion-neutral interactions form a negative space charge that is involved in the ion beam neutralization. After the extraction, both the angular divergence and damping of the beam are essential to settle the position of the substrate. The beam angular divergence is established by the ion trajectories in the extraction region and also is strongly influenced by the ion beam neutralization. The shape and thickness of the space charge near the grid, which in turn is determined by the beam intensity, grid characteristics and target plasma parameters is necessary to be investigated. Positive ion bombardment plays an important role in the plasma treatments of polymers. This was the reason that investigations about the surface modifications of polymers in a positive oxygen ion beam-low density plasma (IB-LDP) system were carried out by our group [2-6]. In such system the electrons of the low-density target plasma neutralize the positive space charge of the beam and also that brought by the beam onto the polymer (insulator) surface. Results concerning the investigations of the IB-LDP system, in oxygen, by Langmuir probe method, in different experimental conditions are given in the present paper. They are compared with those obtained by using Monte Carlo method for elementary processes (ion charge transfer, electronic ionisation) in 'particle in cell' numerical simulation. (authors)

  4. Measuring the electron beam energy in a magnetic bunch compressor

    International Nuclear Information System (INIS)

    Within this thesis, work was carried out in and around the first bunch compressor chicane of the FLASH (Free-electron LASer in Hamburg) linear accelerator in which two distinct systems were developed for the measurement of an electron beams' position with sub-5 μm precision over a 10 cm range. One of these two systems utilized RF techniques to measure the difference between the arrival-times of two broadband electrical pulses generated by the passage of the electron beam adjacent to a pickup antenna. The other system measured the arrival-times of the pulses from the pickup with an optical technique dependent on the delivery of laser pulses which are synchronized to the RF reference of the machine. The relative advantages and disadvantages of these two techniques are explored and compared to other available approaches to measure the same beam property, including a time-of-flight measurement with two beam arrival-time monitors and a synchrotron light monitor with two photomultiplier tubes. The electron beam position measurement is required as part of a measurement of the electron beam energy and could be used in an intra-bunch-train beam-based feedback system that would stabilize the amplitude of the accelerating field. By stabilizing the accelerating field amplitude, the arrival-time of the electron beam can be made more stable. By stabilizing the electron beam arrival-time relative to a stable reference, diagnostic, seeding, and beam-manipulation lasers can be synchronized to the beam. (orig.)

  5. The ATLAS Diamond Beam Monitor

    CERN Document Server

    Schaefer, Douglas; The ATLAS collaboration

    2015-01-01

    After the first three years of the LHC running the ATLAS experiment extracted it's pixel detector system to refurbish and re-position the optical readout drivers and install a new barrel layer of pixels. The experiment has also taken advantage of this access to also install a set of beam monitoring telescopes with pixel sensors, four each in the forward and backward regions. These telescopes were assembled based on chemical vapour deposited (CVD) diamond sensors to survive in this high radiation environment without needing extensive cooling. This talk will describe the lessons learned in construction and commissioning of the ATLAS x Diamond Beam Monitor (DBM). We will show results from the construction quality assurance tests, commissioning performance, including results from cosmic ray running in early 2015 and also expected first results from LHC run 2 collisions.

  6. Motion compensation with a scanned ion beam: a technical feasibility study

    OpenAIRE

    Kraft Gerhard; Haberer Thomas; Bert Christoph; Grözinger Sven; Rietzel Eike

    2008-01-01

    Abstract Background Intrafractional motion results in local over- and under-dosage in particle therapy with a scanned beam. Scanned beam delivery offers the possibility to compensate target motion by tracking with the treatment beam. Methods Lateral motion components were compensated directly with the beam scanning system by adapting nominal beam positions according to the target motion. Longitudinal motion compensation to mitigate motion induced range changes was performed with a dedicated w...

  7. Colliding Crystalline Beams

    International Nuclear Information System (INIS)

    The understanding of crystalline beams has advanced to the point where one can now, with reasonable confidence, undertake an analysis of the luminosity of colliding crystalline beams. Such a study is reported here. It is necessary to observe the criteria, previously stated, for the creation and stability of crystalline beams. This requires, firstly, the proper design of a lattice. Secondly, a crystal must be formed, and this can usually be done at various densities. Thirdly, the crystals in a colliding-beam machine are brought into collision. We study all of these processes using the molecular dynamics (MD) method. The work parallels what was done previously, but the new part is to study the crystal-crystal interaction in collision. We initially study the zero-temperature situation. If the beam-beam force (or equivalent tune shift) is too large then over-lapping crystals can not be created (rather two spatially separated crystals are formed). However, if the beam-beam force is less than but comparable to that of the space-charge forces between the particles, we find that overlapping crystals can be formed and the beam-beam tune shift can be of the order of unity. Operating at low but non-zero temperature can increase the luminosity by several orders of magnitude over that of a usual collider. The construction of an appropriate lattice, and the development of adequately strong coding, although theoretically achievable, is a challenge in practice

  8. Time-resolved measure technique for electron beam envelope basing on synchronous framing and streaking principle

    CERN Document Server

    Xiaoguo, Jiang; Zhiyong, Yang; Huang, Zhang; Yi, Wang; Tao, Wei

    2015-01-01

    The time-resolved electron beam envelope parameters including sectional distribution and position are important and necessary for the study of beam transmission characteristics in the magnetic field and verifying the magnetic field setup rationality. One kind of high time-resolved beam envelope measurement system has developed recently. It is mainly constituted of high framing camera and streak camera. It can obtain 3 panoramic images of the beam and the time continuous information of the given beam cross section at one time. The recently obtained data has proved that several fast vibration of beam envelope along the diameter direction occur during the rising edge and the falling edge of the electron beam. The vibration period is about several nanoseconds. The effect of magnetic field on the electron beam is also observed and verified. The beam debug experiments have proved that the existing beam transmission design is reasonable and viable. The beam envelope measurement system will establish a good foundatio...

  9. Dosimetric precision of an ion beam tracking system

    International Nuclear Information System (INIS)

    Scanned ion beam therapy of intra-fractionally moving tumors requires motion mitigation. GSI proposed beam tracking and performed several experimental studies to analyse the dosimetric precision of the system for scanned carbon beams. A beam tracking system has been developed and integrated in the scanned carbon ion beam therapy unit at GSI. The system adapts pencil beam positions and beam energy according to target motion. Motion compensation performance of the beam tracking system was assessed by measurements with radiographic films, a range telescope, a 3D array of 24 ionization chambers, and cell samples for biological dosimetry. Measurements were performed for stationary detectors and moving detectors using the beam tracking system. All detector systems showed comparable data for a moving setup when using beam tracking and the corresponding stationary setup. Within the target volume the mean relative differences of ionization chamber measurements were 0.3% (1.5% standard deviation, 3.7% maximum). Film responses demonstrated preserved lateral dose gradients. Measurements with the range telescope showed agreement of Bragg peak depth under motion induced range variations. Cell survival experiments showed a mean relative difference of -5% (-3%) between measurements and calculations within the target volume for beam tracking (stationary) measurements. The beam tracking system has been successfully integrated. Full functionality has been validated dosimetrically in experiments with several detector types including biological cell systems

  10. Dosimetric precision of an ion beam tracking system

    Directory of Open Access Journals (Sweden)

    Kraft Gerhard

    2010-06-01

    Full Text Available Abstract Background Scanned ion beam therapy of intra-fractionally moving tumors requires motion mitigation. GSI proposed beam tracking and performed several experimental studies to analyse the dosimetric precision of the system for scanned carbon beams. Methods A beam tracking system has been developed and integrated in the scanned carbon ion beam therapy unit at GSI. The system adapts pencil beam positions and beam energy according to target motion. Motion compensation performance of the beam tracking system was assessed by measurements with radiographic films, a range telescope, a 3D array of 24 ionization chambers, and cell samples for biological dosimetry. Measurements were performed for stationary detectors and moving detectors using the beam tracking system. Results All detector systems showed comparable data for a moving setup when using beam tracking and the corresponding stationary setup. Within the target volume the mean relative differences of ionization chamber measurements were 0.3% (1.5% standard deviation, 3.7% maximum. Film responses demonstrated preserved lateral dose gradients. Measurements with the range telescope showed agreement of Bragg peak depth under motion induced range variations. Cell survival experiments showed a mean relative difference of -5% (-3% between measurements and calculations within the target volume for beam tracking (stationary measurements. Conclusions The beam tracking system has been successfully integrated. Full functionality has been validated dosimetrically in experiments with several detector types including biological cell systems.

  11. Beam-beam effect seen through forced vibration

    International Nuclear Information System (INIS)

    In electron accelerator, tune is measured by giving beam transverse forced vibration caused by RF frequency. It is well known that beam-beam parameter can be measured if beam-beam interaction exists. Generally, small value is chosen as the amplitude of forced vibration, and many researches were done in this case. In this report, we discuss effect of resonance caused by beam-beam interaction in case of amplitude of forced vibration being big. (author)

  12. Low Energy High Brilliance Beam Characterization

    CERN Document Server

    Bähr, J

    2005-01-01

    Low energy high brilliance beam characterization plays an important role for electron sources and injectors of Free Electron Lasers (FELs) and electron linear accelerators as for example the future ILC project. The topic is discussed basing on solutions of the PITZ facility (PhotoInjector Test facility Zeuthen) which are compared with methods applied at other facilities. The properties of an electron beam produced at a laser-driven rf-gun is mainly influenced also by characteristics of the laser beam and the electron gun itself. Therefore aspects of diagnostics will be also discussed for the laser, laser beam line and gun as well. The main properties of the electron beam are transverse and longitudinal phase space and charge as well. The measurement of transverse beam size and position, transverse emittance, charge, beam current, and longitudinal phase space will be discussed in detail. The measurements of the transverse emittance at PITZ is based on a single slit method. The measurement of the longitudinal p...

  13. Performance of the ATLAS Beam Diagnostic Systems

    CERN Document Server

    Macek, B; The ATLAS collaboration

    2010-01-01

    The beam diagnostic system of the ATLAS detector comprises two diamond sensor based devices. The innovative Beam Conditions Monitor (BCM) is aimed at resolving background from collision particles by sub-ns time-of-flight measurement. The Beam Loss Monitor (BLM) is a clone of the LHC machine BLM system, replacing ionization chambers with diamond sensors. BCM uses 16 1x1 cm2 0.5 mm thick polycrystalline chemical vapor deposition (pCVD) diamond sensors arranged in 8 positions at a radius r ≈ 55 mm, ~1.9 m up- and down-stream the interaction point. Time measurements at 2.56 GHz sampling rate are performed to distinguish between collision and shower particles from beam incidents. A FPGA-based readout system performs real-time data analysis and interfaces the results to ATLAS and the LHC beam permit system. The diamond sensors, the detector modules and their readout system are described. Results of performance with LHC beams of increasing energy and intensity including timing separation of collisions from beam re...

  14. Laser beam propagation in atmospheric turbulence

    Science.gov (United States)

    Murty, S. S. R.

    1979-01-01

    The optical effects of atmospheric turbulence on the propagation of low power laser beams are reviewed in this paper. The optical effects are produced by the temperature fluctuations which result in fluctuations of the refractive index of air. The commonly-used models of index-of-refraction fluctuations are presented. Laser beams experience fluctuations of beam size, beam position, and intensity distribution within the beam due to refractive turbulence. Some of the observed effects are qualitatively explained by treating the turbulent atmosphere as a collection of moving gaseous lenses of various sizes. Analytical results and experimental verifications of the variance, covariance and probability distribution of intensity fluctuations in weak turbulence are presented. For stronger turbulence, a saturation of the optical scintillations is observed. The saturation of scintillations involves a progressive break-up of the beam into multiple patches; the beam loses some of its lateral coherence. Heterodyne systems operating in a turbulent atmosphere experience a loss of heterodyne signal due to the destruction of coherence.

  15. 锥形束CT测量山东地区6-19岁正常骨面型儿童青少年的舌骨位置%The normal measurements of the hyoid bone position in populations aged 6-19 years from Shandong using cone-beam CT

    Institute of Scientific and Technical Information of China (English)

    蒋英英; 胥欣; 胡温庭

    2015-01-01

    BACKGROUND:With the extensive application of cone-beam CT in oral and craniofacial surgery, a clear hyoid bone position indicator for normal population has important implications for the change of hyoid bone position before and after orthodontics. OBJECTIVE:To determine the cone-beam CT measurement range of hyoid bone position in populations aged 6-19 years from Shandong, so as to provide a reference marker for the change of hyoid bone position before and after orthodontics in local children and adolescents. METHODS:Totaly 254 healthy children (120 males and 134 females) aged 6-19 years from Shandong Province were subjected to cone-beam CT scan of the hyoid bone. Mimics10.01 was used to evaluate the linear and angular measurements of hyoid bone position, and then the normal value range was confirmed. Independent-samplet-test was used for analysis of gender difference and 95% confidence interval was calculated. RESULTS AND CONCLUSION: There were gender differences in a part of indicators of hyoid bone position among 14-15 years, 16-17 years, 18-19 years groups (P < 0.05). For children aged 12-13 years, the hyoid bone position vertical to the base of skul and upper jaw bone is lower in males than in females. For children aged 14-15 years and 18-19 years, the hyoid bone horizontal to the cervical spine is more forward in males than in females.%背景:锥形束 CT 在口腔颅颌面部的应用越来越广泛,明确正常人群的舌骨位置对于判断正畸治疗前后舌骨的位置变化和对上气道的影响有重要意义。目的:确定山东地区6-19岁正常骨面型的儿童青少年舌骨位置的锥形束CT测量值范围,为当地儿童青少年正畸治疗前后舌骨位置的改变程度提供参考依据。方法:对254例(男120例,女134例)山东地区正常骨面型的6-19岁人群的锥形束CT图像进行分析,应用Mimics 10.01软件在最大矢状面上对舌骨位置进行线性和角度测量,确定舌骨位

  16. Optimal Design of Laminated Composite Beams

    DEFF Research Database (Denmark)

    Blasques, José Pedro Albergaria Amaral

    This thesis presents an optimal design framework for the structural design of laminated composite beams. The possibility of improving the static and dynamic performance of laminated composite beam through the use of optimal design techniques motivates the investigation presented here. A structural...... is able to account for the effects of material anisotropy and inhomogeneity in the global response of the beam. Beam finite element models allow for a significant reduction in problem size and are therefore an efficient alternative in computationally intensive applications like optimization frameworks......, and the position of the cross section shear and mass center, are considered. The proposed optimal design framework can be applied to tailor the static and dynamic properties of laminated composite structures like wind turbine blades....

  17. Development of slowed down beams at GSI

    International Nuclear Information System (INIS)

    The NUSTAR/HISPEC slowed down beam project at GSI/FAIR is dedicated to rare isotopes with energies of upto 10 MeV/u. These radioactive beams will be used for spectroscopy and reactions studies. The setup for slowing down will utilize a thick degrader positioned after the FRS/Super-FRS separators at GSI/FAIR, followed by transmission detectors for energy and trajectory reconstruction. As a test, Coulomb excitation of a slowed down 64Ni beam on a gold target was performed in Sep-Oct 2008 at GSI. TPC and MCP detectors were used for the tracking of the beam before and after slowing it down. The gold target, placed after the tracking setup, was surrounded partially with two DSSSDs and NaI γ-detectors. The results from the test experiment and a comparison to simulations are presented.

  18. Beam coupling impedances of fast transmission-line kickers.

    Energy Technology Data Exchange (ETDEWEB)

    Kurennoy, S. (Sergey)

    2002-01-01

    Fast transmission-line kickers contain no ferrite and consist of two long metallic parallel plates supported by insulators inside a beam pipe. A beam is deflected by both the electric and magnetic fields of a TEM wave created by a pulse propagating along the strips in the direction opposite to the beam. Computations of the beam coupling impedances for such structures are difficult because of their length. In the paper, the beam coupling impedances of transmission-line kickers are calculated by combining analytical and numerical methods: the wake potentials computed in short models are extended analytically to obtain the wakes for the long kickers, and then the corresponding beam impedances are derived. At very low frequencies the results are compared with simple analytical expressions for the coupling impedances of striplines in beam position monitors.

  19. Array Pattern Synthesis Using a Digital Position Shift Method

    Directory of Open Access Journals (Sweden)

    C. Han

    2016-09-01

    Full Text Available Considering all possible steering directions for beam scanning, a digital position shift method (DPSM is presented to minimize the Peak Sidelobe Level (PSL by searching the best position solution for every sensor and calculating the pattern with position offset factor. For the truly minimum PSL, digital position shift with optimal amplitude (DPSOA is considered simultaneously for beam scanning. For searching the best solution to the two methods, constrained conditions for position shift range and amplitude range are described. The method of feedback particle swarm optimization (FPSO is presented to obtain a large searching space and fast convergence in local space with refined solution. Numerical examples show that the optimized results by DPSM and DPSOA in all steering directions can be used in beam scanning for its digital realization. When compared with the other techniques published in the literature, especially the steering direction close to endfire direction, this method has lower PSL when the main beam width is maintained.

  20. Process for servicing a jet pump hold down beam in a nuclear reactor

    International Nuclear Information System (INIS)

    This patent describes a process for remotely removing a jet pump hold down beam mounted between opposed members in a nuclear reactor, the hold down beam having a beam body, a pair of opposed beam tabs extending outwardly from the beam body, a pair of positioning trunnions, and a threaded beam bolt received within a correspondingly-threaded channel extending through the beam body, a lower end of the beam bolt extending through an aperture formed in a beam bolt retainer plate, the retainer plate being coupled by a connecting member to the jet pump, the beam bolt being rotatably adjusted within the beam channel so as to urge the beam tabs against the opposed reactor members. It comprises grasping the beam trunnions; depressing the beam tabs; rotating the beam approximately 90 about the beam bolt so as to remove the beam tabs from the opposed reactor members; removing the retainer plate connecting member in its entirety from the jet pump; and removing the entire hold down beam, retainer plate, and retainer plate connecting member from the jet pump

  1. Laser Beam Focus Analyser

    DEFF Research Database (Denmark)

    Nielsen, Peter Carøe; Hansen, Hans Nørgaard; Olsen, Flemming Ove;

    2007-01-01

    The quantitative and qualitative description of laser beam characteristics is important for process implementation and optimisation. In particular, a need for quantitative characterisation of beam diameter was identified when using fibre lasers for micro manufacturing. Here the beam diameter limits...... the obtainable features in direct laser machining as well as heat affected zones in welding processes. This paper describes the development of a measuring unit capable of analysing beam shape and diameter of lasers to be used in manufacturing processes. The analyser is based on the principle of a rotating...... mechanical wire being swept through the laser beam at varying Z-heights. The reflected signal is analysed and the resulting beam profile determined. The development comprised the design of a flexible fixture capable of providing both rotation and Z-axis movement, control software including data capture...

  2. ILC Beam Energy Measurement by means of Laser Compton Backscattering

    CERN Document Server

    Muchnoi, N; Viti, M

    2008-01-01

    A novel, non-invasive method of measuring the beam energy at the International Linear Collider is proposed. Laser light collides head-on with beam particles and either the energy of the Compton scattered electrons near the kinematic end-point is measured or the positions of the Compton backscattered $\\gamma$-rays, the edge electrons and the unscattered beam particles are recorded. A compact layout for the Compton spectrometer is suggested. It consists of a bending magnet and position sensitive detectors operating in a large radiation environment. Several options for high spatial resolution detectors are discussed. Simulation studies support the use of an infrared or green laser and quartz fiber detectors to monitor the backscattered photons and edge electrons. Employing a cavity monitor, the beam particle position downstream of the magnet can be recorded with submicrometer precision. Such a scheme provides a feasible and promising method to access the incident beam energy with precisions of $10^{-4}$ or bette...

  3. Proton Beam Energy Characterization

    OpenAIRE

    Marus, Lauren A.; Engle, J.W.; John, K. D.; Birnbaum, E. R.; Nortier, F. M.

    2015-01-01

    Introduction The Los Alamos Isotope Production Facility (IPF) is actively engaged in the development of isotope production technologies that can utilize its 100 MeV proton beam. Characterization of the proton beam energy and current is vital for optimizing isotope production and accurately conducting research at the IPF. Motivation In order to monitor beam intensity during research irradiations, aluminum foils are interspersed in experimental stacks. A theoretical yield of 22Na from...

  4. Hyperon beam physics

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, P.S.

    1996-03-01

    This report reviews the present status and recent results in hyperon physics concentrating on results from high energy hyperon beam experiments performed at Fermilab over the past several years. The report focuses on hyperon production polarization, precision hyperon magnetic moment measurements and radiative decay studies. Modern charged hyperon beam experiments are characterized by {approx}100m long apparatus and hyperon beams with {gamma}{sub Y}{approx}100 and hyperon fluxes in the 1-100 kHz range.

  5. Chilled beam application guidebook

    CERN Document Server

    Butler, David; Gräslund, Jonas; Hogeling, Jaap; Lund Kristiansen, Erik; Reinikanen, Mika; Svensson, Gunnar

    2007-01-01

    Chilled beam systems are primarily used for cooling and ventilation in spaces, which appreciate good indoor environmental quality and individual space control. Active chilled beams are connected to the ventilation ductwork, high temperature cold water, and when desired, low temperature hot water system. Primary air supply induces room air to be recirculated through the heat exchanger of the chilled beam. In order to cool or heat the room either cold or warm water is cycled through the heat exchanger.

  6. Semiconductor laser beam bending

    OpenAIRE

    YILDIRIM, REMZİ; ÇELEBİ, FATİH VEHBİ

    2015-01-01

    This study is about a single-component cylindrical structured lens with a gradient curve that was used for bending laser beams. It operates under atmospheric conditions and bends the laser beam independently of temperature, pressure, polarity, polarization, magnetic field, electric field, radioactivity, and gravity. A single-piece cylindrical lens that can bend laser beams was developed. Lenses are made of transparent, tinted, or colored glass and are used to undermine or absorb the energy of...

  7. Mechanical beam isolator

    International Nuclear Information System (INIS)

    Back-reflections from a target, lenses, etc. can gain energy passing backwards through a laser just like the main beam gains energy passing forwards. Unless something blocks these back-reflections early in their path, they can seriously damage the laser. A Mechanical Beam Isolator is a device that blocks back-reflections early, relatively inexpensively, and without introducing aberrations to the laser beam

  8. Beam cavity interaction

    CERN Document Server

    Gamp, A

    2011-01-01

    We begin by giving a description of the rf generator-cavity-beam coupled system in terms of basic quantities. Taking beam loading and cavity detuning into account, expressions for the cavity impedance as seen by the generator and as seen by the beam are derived. Subsequently methods of beam-loading compensation by cavity detuning, rf feedback, and feed-forward are described. Examples of digital rf phase and amplitude control for the special case of superconducting cavities are also given. Finally, a dedicated phase loop for damping synchrotron oscillations is discussed.

  9. Two-dimensional visualization of cluster beams by microchannel plates

    CERN Document Server

    Khoukaz, Alfons; Grieser, Silke; Hergemöller, Ann-Katrin; Köhler, Esperanza; Täschner, Alexander

    2013-01-01

    An advanced technique for a two-dimensional real time visualization of cluster beams in vacuum as well as of the overlap volume of cluster beams with particle accelerator beams is presented. The detection system consists of an array of microchannel plates (MCP) in combination with a phosphor screen which is read out by a CCD camera. This setup together with the ionization of a cluster beam by an electron or ion beam allows for spatial resolved investigations of the cluster beam position, size, and intensity. Moreover, since electrically uncharged clusters remain undetected, the operation in an internal beam experiment opens the way to monitor the overlap region and thus the position and size of an accelerator beam crossing an originally electrically neutral cluster jet. The observed intensity distribution of the recorded image is directly proportional to the convolution of the spatial ion beam and cluster beam intensities and is by this a direct measure of the two-dimensional luminosity distribution. This inf...

  10. Simulation of Beam-Beam Background at CLIC

    CERN Document Server

    Sailer, A

    2010-01-01

    The dense beams used at CLIC to achieve a high luminosity will cause a large amount of background particles through beam-beam interactions. Generator level studies with GUINEAPIG and full detector simulation studies with an ILD based CLIC detector have been performed to evaluate the amount of beam-beam back- ground hitting the vertex detector.

  11. Rf beam control for the AGS Booster

    Energy Technology Data Exchange (ETDEWEB)

    Brennan, J.M.

    1994-09-26

    RF beam control systems for hadron synchrotrons have evolved over the past three decades into an essentially standard design. The key difference between hadron and lepton machines is the absence of radiation damping and existence of significant frequency variation in the case of hadrons. Although the motion of the hadron in the potential well of the rf wave is inherently stable it is not strongly damped. Damping must be provided by electronic feedback through the accelerating system. This feedback is typically called the phase loop. The technology of the rf beam control system for the AGS Booster synchrotron is described. First, the overall philosophy of the design is explained in terms of a conventional servo system that regulates the beam horizontal position in the vacuum chamber. The concept of beam transfer functions is fundamental to the mathematics of the design process and is reviewed. The beam transfer functions required for this design are derived from first principles. An overview of the beam signal pick-ups and high level rf equipment is given. The major subsystems, the frequency program, the heterodyne system, and beam feedback loops, are described in detail. Beyond accelerating the beam, the rf system must also synchronize the bunches in the Booster to the buckets in the AGS before transfer. The technical challenge in this process is heightened by the need to accomplish synchronization while the frequency is still changing. Details of the synchronization system are given. This report is intended to serve two purposes. One is to document the hardware and performance of the systems that have been built. The other is to serve as a tutorial vehicle from which the non-expert can not only learn the details of this system but also learn the principles of beam control that have led to the particular design choices made.

  12. Fluorescent fluid interface position sensor

    Science.gov (United States)

    Weiss, Jonathan D.

    2004-02-17

    A new fluid interface position sensor has been developed, which is capable of optically determining the location of an interface between an upper fluid and a lower fluid, the upper fluid having a larger refractive index than a lower fluid. The sensor functions by measurement, of fluorescence excited by an optical pump beam which is confined within a fluorescent waveguide where that waveguide is in optical contact with the lower fluid, but escapes from the fluorescent waveguide where that waveguide is in optical contact with the upper fluid.

  13. Benign positional vertigo

    Science.gov (United States)

    Vertigo - positional; Benign paroxysmal positional vertigo; BPPV: dizziness- positional ... Benign positional vertigo is also called benign paroxysmal positional vertigo (BPPV). It is caused by a problem in the inner ear. ...

  14. Vibrating Beam With Spatially Periodic Stiffness

    Science.gov (United States)

    Townsend, John S.

    1989-01-01

    Report presents theoretical analysis of vibrations of simply supported beam, bending stiffness varying about steady value, sinusoidally with position along length. Problem of practical importance because related to vibrations of twisted-pair electric-power transmission lines. Twists promote nonuniform shedding of vortexes and prevents resonant accumulation of vibrational energy from wind.

  15. Reconstruction of negative hydrogen ion beam properties from beamline diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Ruf, Benjamin

    2014-09-25

    For the experimental fusion reactor ITER, which should show the feasibility of sustaining a fusion plasma with a positive power balance, some technology still has to be developed, amongst others also the plasma heating system. One heating technique is the neutral beam injection (NBI). A beam of fast deuterium atoms is injected into the fusion plasma. By heavy particle collisions the beam particles give their energy to the plasma. A NBI system consists of three major components. First, deuterium ions are generated in a low temperature, low pressure plasma of an ion source. At ITER, the requirements on the beam energy of 1 MeV cause the necessity of negative charged deuterium ions. Secondly, the ions are accelerated within an acceleration system with several grids, where the plasma grid is the first grid. The grids are on different descending high voltage potentials. The source itself is on the highest negative potential. Thirdly, the fast deuterium ions have to be neutralised. This thesis deals with the second step in the mentioned beam system, the ion acceleration and beam formation. The underlying experiments and measurements were carried out at the testbeds BATMAN (BAvarianTest MAchine for Negative ions) and ELISE (Extraction from a Large Ion Source Experiment) at the Max-Planck-Institut fuer Plasmaphysik Garching (IPP Garching). The main goal of this thesis is to provide a tool which allows the determination of the beam properties. These are beam divergence, stripping losses and beam inhomogeneity. For this purpose a particle trajectory code has been developed from scratch, namely BBC-NI (Bavarian Beam Code for Negative Ions). The code is able to simulate the whole beam and the outcome of several beam diagnostic tools. The data obtained from the code together with the measurements of the beam diagnostic tools should allow the reconstruction of the beam properties. The major beam diagnostic tool, which is used in this thesis, is the beam emission spectroscopy

  16. Damping of a vibrating beam

    NARCIS (Netherlands)

    Hietanen, Jarmo; Bomer, Johan; Jonsmann, Jacques; Olthuis, Wouter; Bergveld, Piet; Kaski, Kimmo

    2000-01-01

    This study examines the vibration in a beam with one fixed end. The set-up consisted of a beam with one end clamped and a rigid plate having the same thickness of the beam, located adjacent to the unfixed end of the beam. The gap between the beam and the plate varied from 4 to 128 μm depending on th

  17. Focused ion beams using a high-brightness plasma source

    Science.gov (United States)

    Guharay, Samar

    2002-10-01

    High-brightness ion beams, with low energy spread, have merits for many new applications in microelectronics, materials science, and biology. Negative ions are especially attractive for the applications that involve beam-solid interactions. When negative ions strike a surface, especially an electrically isolated surface, the surface charging voltage is limited to few volts [1]. This property can be effectively utilized to circumvent problems due to surface charging, such as device damage and beam defocusing. A compact plasma source, with the capability to deliver either positive or negative ion beams, has been developed. H- beams from this pulsed source showed brightness within an order of magnitude of the value for beams from liquid-metal ion sources. The beam angular intensity is > 40 mAsr-1 and the corresponding energy spread is 1 Acm-2 and a spot size of 100 nm. Such characteristics of focused beam parameters, using a dc source, will immediately open up a large area of new applications. [1] P. N. Guzdar, A. S. Sharma, S. K. Guharay, "Charging of substrates irradiated by particle beams" Appl. Phys. Lett. 71, 3302 (1997). [2] S. K. Guharay, E. Sokolovsky, J. Orloff, "Characteristics of ion beams from a Penning source for focused ion beam applications" J. Vac. Sci Technol. B17, 2779 (1999).

  18. Beam distribution reconstruction simulation for electron beam probe

    CERN Document Server

    Feng, Yongchun; Li, Peng; Kang, Xincai; Yin, Yan; Liu, Tong; You, Yaoyao; Chen, Yucong; Zhao, Tiecheng; Xu, Zhiguo; Wang, Yanyu; Yuan, Youjin

    2016-01-01

    Electron beam probe (EBP) is a new principle detector, which makes use of a low-intensity and low-energy electron beam to measure the transverse profile, bunch shape, beam neutralization and beam wake field of an intense beam with small dimensions. While can be applied to many aspects, we limit our analysis to beam distribution reconstruction. This kind of detector is almost non-interceptive for all of the beam and does not disturb the machine environment. In this paper, we present the theoretical aspects behind this technique for beam distribution measurement and some simulation results of the detector involved. First, a method to obtain parallel electron beam is introduced and a simulation code is developed. And then, EBP as a profile monitor for dense beam is simulated using fast scan method under various target beam profile, such as KV distribution, waterbag distribution, parabolic distribution, Gaussian distribution and halo distribution. Profile reconstruction from the deflected electron beam trajectory...

  19. Linearizing Intra-Train Beam-Beam Deflection Feedback

    International Nuclear Information System (INIS)

    Beam-beam deflection feedback acting within the crossing time of a single bunch train may be needed to keep linear collider beams colliding at high luminosity. In a short-pulse machine such as the Next Linear Collider (NLC) this feedback must converge quickly to be useful. The non-linear nature of beam-beam deflection vs. beam-beam offset in these machines precludes obtaining both rapid convergence and a stable steady-state lock to beam offsets with a linear feedback algorithm. We show that a simply realizable programmable non-linear amplifier in the feedback loop can linearize the feedback loop, approximately compensating the beam-beam deflection non-linearity. Performance of a prototype non-linear amplifier is shown. Improvement of convergence and stability of the beam-beam feedback loop is simulated

  20. Beaming teaching application

    DEFF Research Database (Denmark)

    Markovic, Milos; Madsen, Esben; Olesen, Søren Krarup;

    2012-01-01

    BEAMING is a telepresence research project aiming at providing a multimodal interaction between two or more participants located at distant locations. One of the BEAMING applications allows a distant teacher to give a xylophone playing lecture to the students. Therefore, rendering of the xylophon...

  1. Ionization beam scanner

    CERN Multimedia

    CERN PhotoLab

    1973-01-01

    Inner structure of an ionization beam scanner, a rather intricate piece of apparatus which permits one to measure the density distribution of the proton beam passing through it. On the outside of the tank wall there is the coil for the longitudinal magnetic field, on the inside, one can see the arrangement of electrodes creating a highly homogeneous transverse electric field.

  2. Positive maps, positive polynomials and entanglement witnesses

    CERN Document Server

    Skowronek, Lukasz

    2009-01-01

    We link the study of positive quantum maps, block positive operators, and entanglement witnesses with problems related to multivariate polynomials. For instance, we show how indecomposable block positive operators relate to biquadratic forms that are not sums of squares. Although the general problem of describing the set of positive maps remains open, in some particular cases we solve the corresponding polynomial inequalities and obtain explicit conditions for positivity.

  3. Positive maps, positive polynomials and entanglement witnesses

    Energy Technology Data Exchange (ETDEWEB)

    Skowronek, Lukasz; Zyczkowski, Karol [Institute of Physics, Jagiellonian University, Krakow (Poland)], E-mail: lukasz.skowronek@uj.edu.pl, E-mail: karol@tatry.if.uj.edu.pl

    2009-08-14

    We link the study of positive quantum maps, block positive operators and entanglement witnesses with problems related to multivariate polynomials. For instance, we show how indecomposable block positive operators relate to biquadratic forms that are not sums of squares. Although the general problem of describing the set of positive maps remains open, in some particular cases we solve the corresponding polynomial inequalities and obtain explicit conditions for positivity.

  4. Mechanically reinforced glass beams

    DEFF Research Database (Denmark)

    Nielsen, Jens Henrik; Olesen, John Forbes

    2007-01-01

    The use of glass as a load carrying material in structural elements is rarely seen even though glass is a popular material for many architects. This is owed to the unreliable and low tensile strength, which is due to surface flaws and high brittleness of the material. These properties lead...... to breakage without any warning or ductility, which can be catastrophic if no precautions are taken. One aspect of this issue is treated here by looking at the possibility of mechanically reinforcing glass beams in order to obtain ductile failure for such a structural component. A mechanically reinforced...... laminated float glass beam is constructed and tested in four-point bending. The beam consist of 4 layers of glass laminated together with a slack steel band glued onto the bottom face of the beam. The glass parts of the tested beams are \\SI{1700}{mm} long and \\SI{100}{mm} high, and the total width of one...

  5. Beam director design report

    Energy Technology Data Exchange (ETDEWEB)

    Younger, F.C.

    1986-08-01

    A design and fabrication effort for a beam director is documented. The conceptual design provides for the beam to pass first through a bending and focusing system (or ''achromat''), through a second achromat, through an air-to-vacuum interface (the ''beam window''), and finally through the vernier steering system. Following an initial concept study for a beam director, a prototype permanent magnet 30/sup 0/ beam-bending achromat and prototype vernier steering magnet were designed and built. In volume II, copies are included of the funding instruments, requests for quotations, purchase orders, a complete set of as-built drawings, magnetic measurement reports, the concept design report, and the final report on the design and fabrication project. (LEW)

  6. Beam director design report

    International Nuclear Information System (INIS)

    A design and fabrication effort for a beam director is documented. The conceptual design provides for the beam to pass first through a bending and focusing system (or ''achromat''), through a second achromat, through an air-to-vacuum interface (the ''beam window''), and finally through the vernier steering system. Following an initial concept study for a beam director, a prototype permanent magnet 300 beam-bending achromat and prototype vernier steering magnet were designed and built. In volume II, copies are included of the funding instruments, requests for quotations, purchase orders, a complete set of as-built drawings, magnetic measurement reports, the concept design report, and the final report on the design and fabrication project

  7. Muon Beam at the Fermilab Test Beam Area

    OpenAIRE

    Denisov, Dmitri; Evdokimov, Valery; Lukić, Strahinja; Ujić, Predrag

    2016-01-01

    The intensities and profiles of the muon beam behind the beam dump of the Fermilab test beam area when the facility is running in the "pion" beam mode are measured and summarized in this note. This muon beam with momenta in the range 10 - 50 GeV/c provides an opportunity to perform various measurements in parallel with other users of the test beam area.

  8. Electron Beam Lifetime in SPEAR3: Measurement and Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Corbett, J.; Huang, X.; Lee, M.; Lui, P.; /SLAC; Sayyar-Rodsari, B.; /Pavilon Tech., Austin

    2007-12-19

    In this paper we report on electron beam lifetime measurements as a function of scraper position, RF voltage and bunch fill pattern in SPEAR3. We then outline development of an empirical, macroscopic model using the beam-loss rate equation. By identifying the dependence of loss coefficients on accelerator and beam parameters, a numerically-integrating simulator can be constructed to compute beam decay with time. In a companion paper, the simulator is used to train a parametric, non-linear dynamics model for the system [1].

  9. Study on electron beam in a low energy plasma focus

    International Nuclear Information System (INIS)

    Electron beam emission was investigated in a low energy plasma focus device (2.2 kJ) using copper hollow anode. Faraday cup was used to estimate the energy of the electron beam. XR100CR X-ray spectrometer was used to explore the impact of the electron beam on the target observed from top-on and side-on position. Experiments were carried out at optimized pressure of argon gas. The impact of electron beam is exceptionally notable with two different approaches using lead target inside hollow anode in our plasma focus device

  10. Segmented ionization chambers for beam monitoring in hadrontherapy

    Science.gov (United States)

    Braccini, Saverio; Cirio, Roberto; Donetti, Marco; Marchetto, Flavio; Pittà, Giuseppe; Lavagno, Marco; La Rosa, Vanessa

    2015-05-01

    Segmented ionization chambers represent a good solution to monitor the position, the intensity and the shape of ion beams in hadrontherapy. Pixel and strip chambers have been developed for both passive scattering and active scanning dose delivery systems. In particular, strip chambers are optimal for pencil beam scanning, allowing for spatial and time resolutions below 0.1 mm and 1 ms, respectively. The MATRIX pixel and the Strip Accurate Monitor for Beam Applications (SAMBA) detectors are described in this paper together with the results of several beam tests and industrial developments based on these prototypes.

  11. Commissioning and First Performance of the LHC Beam Instrumentation

    CERN Document Server

    Jones, O R

    2010-01-01

    This paper will outline the progress with LHC commissioning to date, detailing the performance achieved with all the main LHC beam instrumentation systems. It will include an overview of the beam loss system and its role in machine protection, along with that of the beam position system and its use for automatic orbit control. Results will be shown from the highly sensitive base band tune system as well as the bunch-bybunch and DC beam current transformer systems, the synchrotron light monitoring systems, the wire scanner system and OTR screens.

  12. Interpolating sliding mode observer for a ball and beam system

    Science.gov (United States)

    Luai Hammadih, Mohammad; Hosani, Khalifa Al; Boiko, Igor

    2016-09-01

    A principle of interpolating sliding mode observer is introduced in this paper. The observer incorporates multiple linear observers through interpolation of multiple estimates, which is treated as a type of adaptation. The principle is then applied to the ball and beam system for observation of the slope of the beam from the measurement of the ball position. The linearised model of the ball and beam system using multiple linearisation points is developed. The observer dynamics implemented in Matlab/Simulink Real Time Workshop environment. Experiments conducted on the ball and beam experimental setup demonstrate excellent performance of the designed novel interpolating (adaptive) observer.

  13. Fatigue test of RC beams strengthened with prestressed CFLs

    Science.gov (United States)

    Guo, Xinyan; Huang, Peiyan; Liu, Guangwan; Xie, Jianhe

    2008-11-01

    Applying prestress to fiber reinforced polymer (FRP) can be used more efficiently since a greater portion energy of its tensile capacity is engaged. Based on carbon fiber laminate (CFL), fatigue tests are made to find out the fatigue behavior of reinforced concrete (RC) beams strengthened with prestressed CFL. The interfacial debonding is a main failure mode for RC beams strengthened with prestressed CFLs under the cyclic loading. Furthermore, it has been found that the stress value of CFLs decide whether the additional prestressing has a negative or positive effect on the fatigue behavior of the strengthened beam, and the excessive prestressing would reduce the fatigue life of the strengthened beam.

  14. Rivulet flow over a flexible beam

    CERN Document Server

    Howell, P D; Popova, M G; Stone, H A

    2016-01-01

    We study theoretically and experimentally how a thin layer of liquid flows along a flexible beam. The flow is modelled using lubrication theory and the substrate is modelled as an elastica which deforms according to the Euler-Bernoulli equation. A constant flux of liquid is supplied at one end of the beam, which is clamped horizontally, while the other end of the beam is free. As the liquid film spreads, its weight causes the beam deflection to increase, which in turn enhances the spreading rate of the liquid. This feedback mechanism causes the front position ${\\sigma}$(t) and the deflection angle at the front ${\\phi}$(t) to go through a number of different power-law behaviours. For early times, the liquid spreads like a horizontal gravity current, with ${\\sigma}$(t) = $t^{4/5}$ and ${\\phi}$(t) = $t^{13/5}$. For intermediate times, the deflection of the beam leads to rapid acceleration of the liquid layer, with ${\\sigma}$(t) = $t^4$ and ${\\phi}$(t) = $t^9$. Finally, when the beam has sagged to become almost v...

  15. Zenith Movie showing Phoenix's Lidar Beam (Animation)

    Science.gov (United States)

    2008-01-01

    [figure removed for brevity, see original site] Click on image for animation A laser beam from the Canadian-built lidar instrument on NASA's Phoenix Mars Lander can be seen in this contrast-enhanced sequence of 10 images taken by Phoenix's Surface Stereo Imager on July 26, 2008, during early Martian morning hours of the mission's 61st Martian day after landing. The view is almost straight up and includes about 1.5 kilometer (about 1 mile) of the length of the beam. The camera, from its position close to the lidar on the lander deck, took the images through a green filter centered on light with wavelength 532 nanometers, the same wavelength of the laser beam. The movie has been artificially colored to to approximately match the color that would be seen looking through this filter on Mars. Contrast is enhanced to make the beam more visible. The lidar beam can be seen extending from the lower right to the upper right, near the zenith, as it reflects off particles suspended in the atmosphere. Particles that scatter the beam directly into the camera can be seen to produce brief sparkles of light. In the background, dust can be seen drifting across the sky pushed by winds aloft. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  16. The STAR Vertex Position Detector

    CERN Document Server

    Llope, W J; Nussbaum, T; Hoffmann, G W; Asselta, K; Brandenburg, J D; Butterworth, J; Camarda, T; Christie, W; Crawford, H J; Dong, X; Engelage, J; Eppley, G; Geurts, F; Hammond, J; Judd, E; McDonald, D L; Perkins, C; Ruan, L; Scheblein, J; Schambach, J J; Soja, R; Xin, K; Yang, C

    2014-01-01

    The 2x3 channel pseudo Vertex Position Detector (pVPD) in the STAR experiment at RHIC has been upgraded to a 2x19 channel detector in the same acceptance, called the Vertex Position Detector (VPD). This detector is fully integrated into the STAR trigger system and provides the primary input to the minimum-bias trigger in Au+Au collisions. The information from the detector is used both in the STAR Level-0 trigger and offline to measure the location of the primary collision vertex along the beam pipe and the event "start time" needed by other fast-timing detectors in STAR. The offline timing resolution of single detector channels in full-energy Au+Au collisions is ~100 ps, resulting in a start time resolution of a few tens of picoseconds and a resolution on the primary vertex location of ~1 cm.

  17. Diffraction of a Laser Beam.

    Science.gov (United States)

    Jodoin, Ronald E.

    1979-01-01

    Investigates the effect of the nonuniform irradiance across a laser beam on diffraction of the beam, specifically the Fraunhofer diffraction of a laser beam with a Gaussian irradiance profile as it passes through a circular aperture. (GA)

  18. Electron Beam Lithography

    Science.gov (United States)

    Harriott, Lloyd R.

    1997-04-01

    Electron beams have played a significant role in semiconductor technology for more than twenty years. Early electron beam machines used a raster scanned beam spot to write patterns in electron-sensitive polymer resist materials. The main application of electron beam lithography has been in mask making. Despite the inherently high spatial resolution and wide process margins of electron beam lithography, the writing rate for semiconductor wafers has been too slow to be economically viable on a large scale. In the late 1970's, variable shape electron beam writing was developed, projecting a rectangular beam whose size can be varied for each "shot" exposure of a particular pattern, allowing some integrated circuits to be made economically where a variety of "customized" patterns are desired. In the cell or block projection electron beam exposure technique, a unit cell of a repetitive pattern is projected repeatedly to increase the level of parallelism. This can work well for highly repetitive patterns such as memory chips but is not well suited to complex varying patterns such as microprocessors. The rapid progress in the performance of integrated circuits has been largely driven by progress in optical lithography, through improvements in lens design and fabrication as well as the use of shorter wavelengths for the exposure radiation. Due to limitations from the opacity of lens and mask materials, it is unlikely that conventional optical printing methods can be used at wavelengths below 193 nm or feature sizes much below 180 nm. One candidate technology for a post-optical era is the Scattering with Angular Limitation Projection Electron-beam Lithography (SCALPEL) approach, which combines the high resolution and wide process latitude inherent in electron beam lithography with the throughput of a parallel projection system. A mask consisting of a low atomic number membrane and a high atomic number pattern layer is uniformly illuminated with high energy (100 ke

  19. Beam Imaging and Luminosity Calibration

    CERN Document Server

    Klute, Markus; Salfeld-Nebgen, Jakob

    2016-01-01

    We discuss a method to reconstruct two-dimensional proton bunch densities using vertex distributions accumulated during LHC beam-beam scans. The $x$-$y$ correlations in the beam shapes are studied and an alternative luminosity calibration technique is introduced. We demonstrate the method on simulated beam-beam scans and estimate the uncertainty on the luminosity calibration associated to the beam-shape reconstruction to be below 1\\%.

  20. Electron Beam Production by Pyroelectric Crystals

    CERN Document Server

    Brownridge, J D; Brownridge, James D.; Shafroth, Stephen M.

    2002-01-01

    Pyroelectric crystals are used to produce self-focused electron beams with energies greater than 170 keV. No high voltage power supply or electron gun is needed. The system works by simply changing the temperature of a crystal of LiNbO3 or LiTaO3 by about 100oC in dilute gas. Electron beam energy spectra as well as positive-ion-beam energy spectra and profiles are shown. A change in the crystal temperature of 100oC will cause a spontaneous change in polarization. The change in polarization will be manifested by a change in charge on the surface of the crystal. It is this uncompensated charge that produces the electric field, which accelerates the electrons, or the positive ions and gives rise to the plasma, which in turn focuses them. The source of the accelerated electrons or positive ions is gas molecules ionized near the crystal surface. When the crystal surface is negative electrons are accelerated away from it and positive ions are attracted to the surface. These positive ions reduce the net negative cha...

  1. Gabor lens focusing of a negative ion beam

    Energy Technology Data Exchange (ETDEWEB)

    Palkovic, J.A.; Mills, F.E.; Schmidt, C.; Young, D.E.

    1989-05-01

    Gabor or plasma lenses have previously been used to focus intense beams of positive ions at energies from 10 keV to 5 MeV. It is the large electrostatic field of the non-neutral plasma in the Gabor lens which is responsible for the focusing. Focusing an ion beam with a given sign of charge in a Gabor lens requires a non-neutral plasma with the opposite sign of charge as the beam. A Gabor lens constructed at Fermilab has been used to focus a 30 keV proton beam with good optical quality. We discuss studies of the action of a Gabor lens on a beam of negative ions. A Gabor lens has been considered for matching an H/sup /minus// beam into an RFQ in the redesign of the low energy section of the Fermilab linac. 9 refs., 3 figs., 1 tab.

  2. Gabor lens focusing of a negative ion beam

    International Nuclear Information System (INIS)

    Gabor or plasma lenses have previously been used to focus intense beams of positive ions at energies from 10 keV to 5 MeV. It is the large electrostatic field of the non-neutral plasma in the Gabor lens which is responsible for the focusing. Focusing an ion beam with a given sign of charge in a Gabor lens requires a non-neutral plasma with the opposite sign of charge as the beam. A Gabor lens constructed at Fermilab has been used to focus a 30 keV proton beam with good optical quality. We discuss studies of the action of a Gabor lens on a beam of negative ions. A Gabor lens has been considered for matching an H/sup /minus// beam into an RFQ in the redesign of the low energy section of the Fermilab linac. 9 refs., 3 figs., 1 tab

  3. Design of a Precision Positioning System for the Undulators of the Linac Coherent Light Source

    CERN Document Server

    Trakhtenberg, Emil; Den Hartog, Patric; White, Marion

    2005-01-01

    A precision positioning system has been designed for the Linac Coherent Light Source (LCLS) and a prototype system is being fabricated. The LCLS will use a beam based alignment technique to precisely align all of the segments of the 130-m long undulator line. The requirement for overlap between the electron beam and the x-ray beam, in order to develop and maintain lasing, demands that each of the quadrupoles be aligned within a tolerance of ± 2 μm and that the undulator axis be positioned within ± 10 μm vertically and horizontally. Five cam movers, each with an eccentricity of 1.5 mm, will allow adjustment of a cradle supporting the undulator, its vacuum chamber, a quadrupole, and a beam position monitor. An additional motion transverse to the beam axis allows removal of individual undulators from the beam path. Positioning feedback will be provided by a wire position monitor system and a hydrostatic leveling system.

  4. LHC beam stability and feedback control

    Energy Technology Data Exchange (ETDEWEB)

    Steinhagen, Ralph

    2007-07-20

    This report presents the stability and the control of the Large Hadron Collider's (LHC) two beam orbits and their particle momenta using beam-based feedback systems. The aim of this report is to contribute to a safe and reliable LHC commissioning and machine operation. The first part of the analysis gives an estimate of the expected sources of orbit and energy perturbations that can be grouped into environmental sources, machine-inherent sources and machine element failures: the slowest perturbation due to ground motion, tides, temperature fluctuations of the tunnel and other environmental influences are described in this report by a propagation model that is both qualitatively and quantitatively supported by geophone and beam motion measurements at LEP and other CERN accelerators. The second part of this analysis deals with the control of the two LHC beams' orbit and energy through automated feedback systems. Based on the reading of the more than 1056 beam position monitors (BPMs) that are distributed over the machine, a central global feedback controller calculates new deflection strengths for the more than 1060 orbit corrector magnets (CODs) that are suitable to correct the orbit and momentum around their references. this report provides an analysis of the BPMs and CODs involved in the orbit and energy feedback. The BPMs are based on a wide-band time normaliser circuit that converts the transverse beam position reading of each individual particle bunch into two laser pulses that are separated by a time delay and transmitted through optical fibres to an acquisition card that converts the delay signals into a digital position. A simple error model has been tested and compared to the measurement accuracy of LHC type BPMs, obtained through beam-based measurements in the SPS. The average beam position is controlled through 1060 superconducting and individually powered corrector dipole magnets. The proposed correction in 'time-domain' consists of a

  5. LHC beam stability and feedback control

    International Nuclear Information System (INIS)

    This report presents the stability and the control of the Large Hadron Collider's (LHC) two beam orbits and their particle momenta using beam-based feedback systems. The aim of this report is to contribute to a safe and reliable LHC commissioning and machine operation. The first part of the analysis gives an estimate of the expected sources of orbit and energy perturbations that can be grouped into environmental sources, machine-inherent sources and machine element failures: the slowest perturbation due to ground motion, tides, temperature fluctuations of the tunnel and other environmental influences are described in this report by a propagation model that is both qualitatively and quantitatively supported by geophone and beam motion measurements at LEP and other CERN accelerators. The second part of this analysis deals with the control of the two LHC beams' orbit and energy through automated feedback systems. Based on the reading of the more than 1056 beam position monitors (BPMs) that are distributed over the machine, a central global feedback controller calculates new deflection strengths for the more than 1060 orbit corrector magnets (CODs) that are suitable to correct the orbit and momentum around their references. this report provides an analysis of the BPMs and CODs involved in the orbit and energy feedback. The BPMs are based on a wide-band time normaliser circuit that converts the transverse beam position reading of each individual particle bunch into two laser pulses that are separated by a time delay and transmitted through optical fibres to an acquisition card that converts the delay signals into a digital position. A simple error model has been tested and compared to the measurement accuracy of LHC type BPMs, obtained through beam-based measurements in the SPS. The average beam position is controlled through 1060 superconducting and individually powered corrector dipole magnets. The proposed correction in 'time-domain' consists of a proportional

  6. Beam Stability at the Advanced Photon Source

    CERN Document Server

    Decker, Glenn

    2005-01-01

    The Advanced Photon Source has been in operation since 1996. Since that time, extensive incremental improvements to orbit stabilization systems have been made. This includes the addition of 80 channels of narrowband rf beam position monitors (bpm's), 40 channels of bending magnet photon bpm's, and most recently the inclusion of 36 insertion device photon bpm's into the orbit correction response matrix. In addition, considerable improvements have been made in the area of power supply regulation, both for the main multipole magnets and the steering corrector magnets. The present status of overall performance will be discussed, including long term pointing stability, reproducibility, and AC beam motion.

  7. Simulations of beam-beam and beam-wire interactions in RHIC

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyung J.; Sen, Tanaji; /Fermilab; Abreu, Natalia P.; Fischer, Wolfram; /Brookhaven

    2009-02-01

    The beam-beam interaction is one of the dominant sources of emittance growth and luminosity lifetime deterioration. A current carrying wire has been proposed to compensate long-range beam-beam effects in the LHC and strong localized long-range beam-beam effects are experimentally investigated in the RHIC collider. Tune shift, beam transfer function, and beam loss rate are measured in dedicated experiments. In this paper, they report on simulations to study the effect of beam-wire interactions based on diffusive apertures, beam loss rates, and beam transfer function using a parallelized weak-strong beam simulation code (BBSIMC). The simulation results are compared with measurements performed in RHIC during 2007 and 2008.

  8. Polarized atomic hydrogen beam

    Energy Technology Data Exchange (ETDEWEB)

    Chan, N.; Crowe, D.M.; Lubell, M.S.; Tang, F.C.; Vasilakis, A.; Mulligan, F.J.; Slevin, J.

    1988-12-01

    We describe the design and operating characteristics of a simple polarized atomic hydrogen beam particularly suitable for applications to crossed beams experiments. In addition to experimental measurements, we present the results of detailed computer models, using Monte-Carlo ray tracing techniques, optical analogs, and phase-space methods, that not only provide us with a confirmation of our measurement, but also allow us to characterize the density, polarization, and atomic fraction of the beam at all points along its path. As a subsidiary result, we also present measurements of the relative and absolute efficiencies of the V/G Supavac mass analyzer for masses 1 and 2.

  9. Laser beam quality metrics

    CERN Document Server

    Ross, T Sean

    2013-01-01

    This book is geared toward engineers and laser physicists involved in the development of laser-based systems, especially laser systems for directed energy applications. It begins with a review of basic laser properties and moves to definitions and implications of the various standard beam quality metrics such as [i]M[/i][sup]2[/sup], power in the bucket, brightness, beam parameter product, and Strehl ratio. The practical aspects of beam metrology, which have not been sufficiently addressed in the literature, are amply covered here.

  10. Electron Beam for LHC

    CERN Document Server

    Krasny, M W

    2005-01-01

    A method of delivering a monochromatic electron beam to the LHC interaction points is proposed. In this method, heavy ions are used as carriers of the projectile electrons. Acceleration, storage and collision-stability aspects of such a hybrid beam is discussed and a new beam-cooling method is presented. This discussion is followed by a proposal of the Parasitic Ion-Electron collider at LHC (PIE@LHC). The PIE@LHC provides an opportunity, for the present LHC detectors, to enlarge the scope of their research program by including the program of electron-proton and electron-nucleuscollisions with minor machine and detector investments.

  11. The beam diagnostic system, serving the Serpukhov fast ejection

    CERN Document Server

    Cupérus, J; Kamber, I; Nuttall, J

    1973-01-01

    A set of beam transformers measures the intensity of each bunch, circulating or ejected. Five electrostatic pick-ups measure the radial position of one selected bunch. Secondary emission grids and luminescent screens give the profile and position of the beam at relevant points. Gated radiation detectors monitor beam loss in the ejection area. All signals are digitalized and fed to a minicomputer on line. Readout is via nixies, CRT analogue displays, pen recorders and a teletype. Statistics can be made over a chosen number of acceleration cycles. (5 refs).

  12. Navicular bone position determined by positional MRI

    DEFF Research Database (Denmark)

    Hansen, Philip; Johannsen, Finn E; Hangaard, Stine;

    2016-01-01

    OBJECTIVE: To examine intraobserver, interobserver and between-day reproducibility of positional MRI for evaluation of navicular bone height (NVH) and medial navicular position (MNP). MATERIALS AND METHODS: Positional MRI (pMRI) of the foot was performed on ten healthy participants (0.25 T G-scan...

  13. Testing Long-Range Beam-Beam Compensation for the LHC Luminosity Upgrade

    CERN Document Server

    Rijoff, T L

    2012-01-01

    The performance of the Large Hadron Collider (LHC) at CERN and its minimum crossing angle are limited by the effect of long-range beam-beam collisions. A wire compensators can mitigate part of the long-range effects and may allow for smaller crossing angles, or higher beam intensity. A prototype long-range wire compensator could be installed in the LHC by 2014/15. Since the originally reserved position for such a wire compensator is not available for this first step, we explore other possible options. Our investigations consider various longitudinal and transverse locations, different wire shapes, different optics configurations and several crossing angles between the two colliding beams. Simulations are carried out with the weak-strong code BBtrack. New postprocessing tools are introduced to analyse tune footprints and particle stability. In particular, a new method for the Lyapunov coefficient calculation is implemented. Submitted as "Tesi di laurea" at the University of Milano, 2012.

  14. Beam induced vacuum measurement error in BEPC II

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    When the beam in BEPCII storage ring aborts suddenly, the measured pressure of cold cathode gauges and ion pumps will drop suddenly and decrease to the base pressure gradually. This shows that there is a beam induced positive error in the pressure measurement during beam operation. The error is the difference between measured and real pressures. Right after the beam aborts, the error will disappear immediately and the measured pressure will then be equal to real pressure. For one gauge, we can fit a non-linear pressure-time curve with its measured pressure data 20 seconds after a sudden beam abortion. From this negative exponential decay pumping-down curve, real pressure at the time when the beam starts aborting is extrapolated. With the data of several sudden beam abortions we have got the errors of that gauge in different beam currents and found that the error is directly proportional to the beam current, as expected. And a linear data-fitting gives the proportion coefficient of the equation, which we derived to evaluate the real pressure all the time when the beam with varied currents is on.

  15. Optical Device for Converting a Laser Beam into Two Co-aligned but Oppositely Directed Beams

    Science.gov (United States)

    Jennings, Donald

    2013-01-01

    Optical systems consisting of a series of optical elements require alignment from the input end to the output end. The optical elements can be mirrors, lenses, sources, detectors, or other devices. Complex optical systems are often difficult to align from end-to-end because the alignment beam must be inserted at one end in order for the beam to traverse the entire optical path to the other end. The ends of the optical train may not be easily accessible to the alignment beam. Typically, when a series of optical elements is to be aligned, an alignment laser beam is inserted into the optical path with a pick-off mirror at one end of the series of elements. But it may be impossible to insert the beam at an end-point. It can be difficult to locate the pick-off mirror at the desired position because there is not enough space, there is no mounting surface, or the location is occupied by a source, detector, or other component. Alternatively, the laser beam might be inserted at an intermediate location (not at an end-point) and sent, first in one direction and then the other, to the opposite ends of the optical system for alignment. However, in this case, alignment must be performed in two directions and extra effort is required to co-align the two beams to make them parallel and coincident, i.e., to follow the same path as an end-to-end beam. An optical device has been developed that accepts a laser beam as input and produces two co-aligned, but counter-propagating beams. In contrast to a conventional alignment laser placed at one end of the optical path, this invention can be placed at a convenient position within the optical train and aligned to send its two beams simultaneously along precisely opposite paths that, taken together, trace out exactly the same path as the conventional alignment laser. This invention allows the user the freedom to choose locations within the optical train for placement of the alignment beam. It is also self-aligned by design and requires

  16. Structural Damping with Friction Beams

    Directory of Open Access Journals (Sweden)

    L. Gaul

    2008-01-01

    Full Text Available In the last several years, there has been increasing interest in the use of friction joints for enhancing damping in structures. The joints themselves are responsible for the major part of the energy dissipation in assembled structures. The dissipated work in a joint depends on both the applied normal force and the excitation force. For the case of a constant amplitude excitation force, there is an optimal normal force which maximizes the damping. A ‘passive’ approach would be employed in this instance. In most cases however, the excitation force, as well as the interface parameters such as the friction coefficient, normal pressure distribution, etc., are not constant. In these cases, a ‘semi-active’ approach, which implements an active varying normal force, is necessary. For the ‘passive’ and ‘semi-active’ approaches, the normal force has to be measured. Interestingly, since the normal force in a friction joint influences the local stiffness, the natural frequencies of the assembled structure can be tuned by adjusting the normal force. Experiments and simulations are performed for a simple laboratory structure consisting of two superposed beams with friction in the interface. Numerical simulation of the friction interface requires non-linear models. The response of the double beam system is simulated using a numerical algorithm programmed in MATLAB which models point-to-point friction with the Masing friction model. Numerical predictions and measurements of the double beam free vibration response are compared. A practical application is then described, in which a friction beam is used to damp the vibrations of the work piece table on a milling machine. The increased damping of the table reduces vibration amplitudes, which in turn results in enhanced surface quality of the machined parts, reduction in machine tool wear, and potentially higher feed rates. Optimal positioning of the friction beams is based on knowledge of the mode

  17. Apparatus for servicing a jet pump hold down beam in a nuclear reactor

    International Nuclear Information System (INIS)

    This patent describes an apparatus for replacing the hold down beam of a fluid circulating jet pump mounted in a nuclear reactor, the hold down beam having a beam body, a pair of opposed beam tabs and a pair of opposed beam positioning trunnions extending outwardly from the beam body. It comprises a housing having a lower surface configured to be positionable over the body of the hold down beam; means coupled to the housing for engaging the beam trunnions and securing the beam body against the lower surface of the housing; means coupled to the housing for depressing the beam tabs while the beam body is secured against the lower surface of the housing; means coupled to the trunnion engaging means and the beam tab depressing means for selectively actuating the trunnion engaging means and the beam tab depressing means from a position remote from the nuclear reactor; and means connectable to the housing for selectively changing the directional orientation of the beam

  18. Bunched beam stochastic cooling

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Jie

    1992-09-01

    The scaling laws for bunched-beam stochastic cooling has been derived in terms of the optimum cooling rate and the mixing condition. In the case that particles occupy the entire sinusoidal rf bucket, the optimum cooling rate of the bunched beam is shown to be similar to that predicted from the coasting-beam theory using a beam of the same average density and mixing factor. However, in the case that particles occupy only the center of the bucket, the optimum rate decrease in proportion to the ratio of the bunch area to the bucket area. The cooling efficiency can be significantly improved if the synchrotron side-band spectrum is effectively broadened, e.g. by the transverse tune spread or by using a double rf system.

  19. Bunched beam stochastic cooling

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Jie.

    1992-01-01

    The scaling laws for bunched-beam stochastic cooling has been derived in terms of the optimum cooling rate and the mixing condition. In the case that particles occupy the entire sinusoidal rf bucket, the optimum cooling rate of the bunched beam is shown to be similar to that predicted from the coasting-beam theory using a beam of the same average density and mixing factor. However, in the case that particles occupy only the center of the bucket, the optimum rate decrease in proportion to the ratio of the bunch area to the bucket area. The cooling efficiency can be significantly improved if the synchrotron side-band spectrum is effectively broadened, e.g. by the transverse tune spread or by using a double rf system.

  20. Neutrino beams and experiments

    International Nuclear Information System (INIS)

    After a brief review of the early history of neutrino experiments, the principle of neutrino beams at proton accelerators is described and a survey of neutrino experiments since 1963 is given. ((orig.))